/**
* This test verifies the use of BodyActuator for applying spatial forces to a selected
* body. It checks if using a BodyActuator generates equivalent acceleration compared
* to when applying the forces via mobilityForce.
*
* @author Soha Pouya
*/
void testBodyActuator()
{
using namespace SimTK;
// start timing
std::clock_t startTime = std::clock();
// Setup OpenSim model
Model *model = new Model;
// turn off gravity
model->setGravity(Vec3(0));
//OpenSim body 1: Ground
const Ground& ground = model->getGround();
// OpenSim body 2: A Block
// Geometrical/Inertial properties for the block
double blockMass = 1.0, blockSideLength = 1;
Vec3 blockMassCenter(0);
Inertia blockInertia = blockMass*Inertia::brick(blockSideLength/2,
blockSideLength/2, blockSideLength/2); // for the halves see doxygen for brick
OpenSim::Body *block = new OpenSim::Body("block", blockMass,
blockMassCenter, blockInertia);
// Add display geometry to the block to visualize in the GUI
block->attachGeometry(Brick(Vec3(blockSideLength/2,
blockSideLength/2,
blockSideLength/2)));
Vec3 locationInParent(0, blockSideLength / 2, 0), orientationInParent(0),
locationInBody(0), orientationInBody(0);
FreeJoint *blockToGroundFree = new FreeJoint("blockToGroundBall",
ground, locationInParent, orientationInParent,
*block, locationInBody, orientationInBody);
model->addBody(block);
model->addJoint(blockToGroundFree);
// specify magnitude and direction of applied force and torque
double forceMag = 1.0;
Vec3 forceAxis(1, 1, 1);
Vec3 forceInG = forceMag * forceAxis;
double torqueMag = 1.0;
Vec3 torqueAxis(1, 1, 1);
Vec3 torqueInG = torqueMag*torqueAxis;
// ---------------------------------------------------------------------------
// Use MobilityForces to Apply the given Torques and Forces to the body
// ---------------------------------------------------------------------------
State& state = model->initSystem();
model->getMultibodySystem().realize(state, Stage::Dynamics);
Vector_<SpatialVec>& bodyForces =
model->getMultibodySystem().updRigidBodyForces(state, Stage::Dynamics);
bodyForces.dump("Body Forces before applying 6D spatial force:");
model->getMatterSubsystem().addInBodyTorque(state, block->getMobilizedBodyIndex(),
torqueInG, bodyForces);
model->getMatterSubsystem().addInStationForce(state, block->getMobilizedBodyIndex(),
Vec3(0), forceInG, bodyForces);
bodyForces.dump("Body Forces after applying 6D spatial force to the block");
model->getMultibodySystem().realize(state, Stage::Acceleration);
Vector udotBody = state.getUDot();
udotBody.dump("Accelerations due to body forces");
// clear body forces
bodyForces *= 0;
// update mobility forces
Vector& mobilityForces = model->getMultibodySystem()
.updMobilityForces(state, Stage::Dynamics);
// Apply torques as mobility forces of the ball joint
for (int i = 0; i<3; ++i){
mobilityForces[i] = torqueInG[i];
mobilityForces[i+3] = forceInG[i];
}
mobilityForces.dump("Mobility Forces after applying 6D spatial force to the block");
model->getMultibodySystem().realize(state, Stage::Acceleration);
Vector udotMobility = state.getUDot();
udotMobility.dump("Accelerations due to mobility forces");
// First make sure that accelerations are not zero accidentally
ASSERT(udotMobility.norm() != 0.0 || udotBody.norm() != 0.0);
// Then check if they are equal
for (int i = 0; i<udotMobility.size(); ++i){
ASSERT_EQUAL(udotMobility[i], udotBody[i], SimTK::Eps);
}
// clear the mobility forces
mobilityForces = 0;
// ---------------------------------------------------------------------------
// Use a BodyActuator to Apply the same given Torques and Forces to the body
// ---------------------------------------------------------------------------
// Create and add the body actuator to the model
BodyActuator* actuator = new BodyActuator(*block);
actuator->setName("BodyAct");
model->addForce(actuator);
model->setUseVisualizer(false);
// get a new system and state to reflect additions to the model
State& state1 = model->initSystem();
model->print("TestBodyActuatorModel.osim");
// -------------- Provide control signals for bodyActuator ----------
// Get the default control vector of the model
Vector modelControls = model->getDefaultControls();
// Specify a vector of control signals to include desired torques and forces
Vector fixedControls(6);
for (int i = 0; i < 3; i++){
fixedControls(i) = torqueInG(i);
fixedControls(i + 3) = forceInG(i);
}
fixedControls.dump("Spatial forces applied by body Actuator:");
// Add control values and set their values
actuator->addInControls(fixedControls, modelControls);
model->setDefaultControls(modelControls);
// ------------------- Compute Acc and Compare -------------
// Compute the acc due to spatial forces applied by body actuator
model->computeStateVariableDerivatives(state1);
Vector udotBodyActuator = state1.getUDot();
udotBodyActuator.dump("Accelerations due to body actuator");
// First make sure that accelerations are not zero accidentally
ASSERT(udotMobility.norm() != 0.0 || udotBodyActuator.norm() != 0.0);
// Then verify that the BodyActuator also generates the same acceleration
// as the equivalent applied mobility force
for (int i = 0; i<udotBodyActuator.size(); ++i){
ASSERT_EQUAL(udotMobility[i], udotBodyActuator[i], SimTK::Eps);
}
// -------------- Setup integrator and manager -------------------
RungeKuttaMersonIntegrator integrator(model->getMultibodySystem());
integrator.setAccuracy(integ_accuracy);
Manager manager(*model, integrator);
manager.setInitialTime(0.0);
double final_t = 1.00;
manager.setFinalTime(final_t);
manager.integrate(state1);
// ----------------- Test Copying the model -------------------
// Before exiting lets see if copying the actuator works
BodyActuator* copyOfActuator = actuator->clone();
ASSERT(*copyOfActuator == *actuator);
// Check that de/serialization works
Model modelFromFile("TestBodyActuatorModel.osim");
ASSERT(modelFromFile == *model, __FILE__, __LINE__,
"Model from file FAILED to match model in memory.");
std::cout << " ********** Test BodyActuator time = ********** " <<
1.e3*(std::clock() - startTime) / CLOCKS_PER_SEC << "ms\n" << endl;
}
/**
* This test verifies if using a BodyActuator generates equivalent result in the body
* acceleration compared to when using a combination of PointActuaor, TorqueActuaor
* and BodyActuator.
* It therefore also verifies model consistency when user defines and uses a
* combination of these 3 actuators.
*
* @author Soha Pouya
*/
void testActuatorsCombination()
{
using namespace SimTK;
// start timing
std::clock_t startTime = std::clock();
// Setup OpenSim model
Model *model = new Model;
// turn off gravity
model->setGravity(Vec3(0));
// OpenSim bodies: 1) The ground
const Ground& ground = model->getGround();
//ground.addDisplayGeometry("block.vtp");
// OpenSim bodies: 2) A Block
// Geometrical/Inertial properties for the block
double blockMass = 1.0, blockSideLength = 1.0;
Vec3 blockMassCenter(0);
// Brick Inertia: for the halves see doxygen
Inertia blockInertia = blockMass*Inertia::brick(blockSideLength/2,
blockSideLength/2, blockSideLength/2);
std::cout << "blockInertia: " << blockInertia << std::endl;
OpenSim::Body *block = new OpenSim::Body("block", blockMass,
blockMassCenter, blockInertia);
// Add display geometry to the block to visualize in the GUI
block->attachGeometry(Brick(Vec3(blockSideLength/2,
blockSideLength/2,
blockSideLength/2)));
// Make a FreeJoint from block to ground
Vec3 locationInParent(0, blockSideLength/2, 0), orientationInParent(0), //locationInParent(0, blockSideLength, 0)
locationInBody(0), orientationInBody(0);
FreeJoint *blockToGroundFree = new FreeJoint("blockToGroundFreeJoint",
ground, locationInParent, orientationInParent,
*block, locationInBody, orientationInBody);
// Add the body and joint to the model
model->addBody(block);
model->addJoint(blockToGroundFree);
// specify magnitude and direction of desired force and torque vectors to apply
double forceMag = 1.0;
Vec3 forceAxis(1, 1, 1);
SimTK::UnitVec3 forceUnitAxis(forceAxis); // to normalize
Vec3 forceInG = forceMag * forceUnitAxis;
double torqueMag = 1.0;
Vec3 torqueAxis(1, 2, 1);
SimTK::UnitVec3 torqueUnitAxis(torqueAxis); // to normalize
Vec3 torqueInG = torqueMag*torqueUnitAxis;
// needed to be called here once to build controller for body actuator
/*State& state = */model->initSystem();
// ---------------------------------------------------------------------------
// Add a set of PointActuator, TorqueActuator and BodyActuator to the model
// ---------------------------------------------------------------------------
// Create and add a body actuator to the model
BodyActuator* bodyActuator1 = new BodyActuator(*block);
bodyActuator1->setName("BodyAct1");
bodyActuator1->set_point(Vec3(0, blockSideLength/2, 0));
model->addForce(bodyActuator1);
// Create and add a torque actuator to the model
TorqueActuator* torqueActuator =
new TorqueActuator(*block, ground, torqueUnitAxis, true);
torqueActuator->setName("torqueAct");
model->addForce(torqueActuator);
// Create and add a point actuator to the model
PointActuator* pointActuator =
new PointActuator("block");
pointActuator->setName("pointAct");
pointActuator->set_direction(forceUnitAxis);
pointActuator->set_point(Vec3(0, blockSideLength/2,0));
model->addForce(pointActuator);
// ------ build the model -----
model->print("TestActuatorCombinationModel.osim");
model->setUseVisualizer(false);
// get a new system and state to reflect additions to the model
State& state1 = model->initSystem();
// ------------------- Provide control signals for bodyActuator ----------------
// Get the default control vector of the model
Vector modelControls = model->getDefaultControls();
// Specify a vector of control signals for desired torques and forces
Vector bodyActuator1Controls(6,0.0);
for (int i=0; i<3; i++) bodyActuator1Controls(i) = torqueInG(i); // torque in 3 axes
for (int i=0; i<3; i++) bodyActuator1Controls(i+3) = forceInG(i); // force along 3 axes
bodyActuator1Controls.dump("Spatial forces applied by first Body Actuator:");
// Add control values and set their values
bodyActuator1->addInControls(bodyActuator1Controls, modelControls);
model->setDefaultControls(modelControls);
// ---------------- Provide control signals for torqueActuator -----------------
Vector torqueActuatorControls(1); // input to addInControl should be a Vector
torqueActuatorControls(0) = torqueMag; // axis already defined when initializing
Vector torqueActuatorVector(3); // to print out the 3D vector of applied torque
for (int i = 0; i < 3; i++){
torqueActuatorVector(i) = torqueInG(i);
}
torqueActuatorVector.dump("Torques applied by the Torque Actuator:");
// Add control values and set their values
torqueActuator->addInControls(torqueActuatorControls, modelControls);
model->setDefaultControls(modelControls);
// ------------------ Provide control signals for pointActuator ----------------
Vector pointActuatorControls(1); // input to addInControl should be a Vector
pointActuatorControls(0) = forceMag; // axis already defined when initializing
Vector pointActuatorVector(3); // to print out the whole force vector
for (int i = 0; i < 3; i++){
pointActuatorVector(i) = forceInG(i);
}
pointActuatorVector.dump("Forces applied by the point Actuator:");
// Add control values and set their values
pointActuator->addInControls(pointActuatorControls, modelControls);
model->setDefaultControls(modelControls);
// ----------------------- Compute the acc to Compare later --------------------
// compare the acc due to forces/torques applied by all actuator
model->computeStateVariableDerivatives(state1);
Vector udotActuatorsCombination = state1.getUDot();
udotActuatorsCombination.dump("Accelerations due to all 3 actuators");
// -----------------------------------------------------------------------------
// Add a BodyActuator to enclose all of the above spatial forces in one Actuator
// -----------------------------------------------------------------------------
// Create and add a body actuator to the model
BodyActuator* bodyActuator_sum = new BodyActuator(*block);
bodyActuator_sum->setName("BodyAct_Sum");
model->addForce(bodyActuator_sum);
bodyActuator_sum->set_point(Vec3(0, blockSideLength / 2, 0));
State& state2 = model->initSystem();
model->setUseVisualizer(true);
// Get the default control vector of the model
Vector modelControls_2 = model->getDefaultControls();
// Specify a vector of control signals for desired torques and forces
Vector bodyActuatorSum_Controls(6,0.0);
// make the torque component as the sum of body, torque and point actuators used
// in previous test case
for (int i = 0; i < 3; i++){
bodyActuatorSum_Controls(i) = 2*torqueInG(i);
bodyActuatorSum_Controls(i+3) = 2*forceInG(i);
}
bodyActuatorSum_Controls.dump("Spatial forces applied by 2nd Body Actuator:");
std::cout <<"(encloses sum of the above spatial forces in one BodyActuator)"<< std::endl;
// Add control values and set their values
bodyActuator_sum->addInControls(bodyActuatorSum_Controls, modelControls_2);
model->setDefaultControls(modelControls_2);
// --------------------------- Compute Acc and Compare -------------------------
// now compare the acc due to forces/torques applied by this body actuator
model->computeStateVariableDerivatives(state2);
Vector udotOnlyBodyActuator = state2.getUDot();
udotOnlyBodyActuator.dump("Accelerations due to only-one body actuator");
// Verify that the bodyActuator_sum also generates the same acceleration
// as the equivalent applied by 3 Actuators in previous test case
// Also make sure that accelerations are not zero accidentally
ASSERT(udotOnlyBodyActuator.norm() != 0.0 || udotActuatorsCombination.norm() != 0.0);
for (int i = 0; i<udotActuatorsCombination.size(); ++i){
ASSERT_EQUAL(udotOnlyBodyActuator[i], udotActuatorsCombination[i], 1.0e-12);
}
// ------------------------ Setup integrator and manager -----------------------
RungeKuttaMersonIntegrator integrator(model->getMultibodySystem());
integrator.setAccuracy(integ_accuracy);
Manager manager(*model, integrator);
manager.setInitialTime(0.0);
double final_t = 1.00;
manager.setFinalTime(final_t);
manager.integrate(state2);
std::cout << " ********** Test Actuator Combination time = ********** " <<
1.e3*(std::clock() - startTime) / CLOCKS_PER_SEC << "ms\n" << endl;
}
//==========================================================================================================
// Test Cases
//==========================================================================================================
void testPrescribedForce(OpenSim::Function* forceX, OpenSim::Function* forceY, OpenSim::Function* forceZ,
OpenSim::Function* pointX, OpenSim::Function* pointY, OpenSim::Function* pointZ,
OpenSim::Function* torqueX, OpenSim::Function* torqueY, OpenSim::Function* torqueZ,
vector<SimTK::Real>& times, vector<SimTK::Vec3>& accelerations, vector<SimTK::Vec3>& angularAccelerations)
{
using namespace SimTK;
//==========================================================================================================
// Setup OpenSim model
Model *osimModel = new Model;
//OpenSim bodies
OpenSim::Body& ground = osimModel->getGroundBody();
OpenSim::Body ball;
ball.setName("ball");
// Add joints
FreeJoint free("free", ground, Vec3(0), Vec3(0), ball, Vec3(0), Vec3(0), false);
// Rename coordinates for a free joint
CoordinateSet free_coords = free.getCoordinateSet();
for(int i=0; i<free_coords.getSize(); i++){
std::stringstream coord_name;
coord_name << "free_q" << i;
free_coords.get(i).setName(coord_name.str());
free_coords.get(i).setMotionType(i > 2 ? Coordinate::Translational : Coordinate::Rotational);
}
osimModel->addBody(&ball);
osimModel->addJoint(&free);
// Add a PrescribedForce.
PrescribedForce force(&ball);
if (forceX != NULL)
force.setForceFunctions(forceX, forceY, forceZ);
if (pointX != NULL)
force.setPointFunctions(pointX, pointY, pointZ);
if (torqueX != NULL)
force.setTorqueFunctions(torqueX, torqueY, torqueZ);
counter++;
osimModel->updForceSet().append(&force);
// BAD: have to set memoryOwner to false or program will crash when this test is complete.
osimModel->disownAllComponents();
//Set mass
ball.setMass(ballMass.getMass());
ball.setMassCenter(ballMass.getMassCenter());
ball.setInertia(ballMass.getInertia());
osimModel->setGravity(gravity_vec);
osimModel->print("TestPrescribedForceModel.osim");
delete osimModel;
// Check that serialization/deserialization is working correctly as well
osimModel = new Model("TestPrescribedForceModel.osim");
SimTK::State& osim_state = osimModel->initSystem();
osimModel->getMultibodySystem().realize(osim_state, Stage::Position );
//==========================================================================================================
// Compute the force and torque at the specified times.
const OpenSim::Body& body = osimModel->getBodySet().get("ball");
RungeKuttaMersonIntegrator integrator(osimModel->getMultibodySystem() );
Manager manager(*osimModel, integrator);
manager.setInitialTime(0.0);
for (unsigned int i = 0; i < times.size(); ++i)
{
manager.setFinalTime(times[i]);
manager.integrate(osim_state);
osimModel->getMultibodySystem().realize(osim_state, Stage::Acceleration);
Vec3 accel, angularAccel;
osimModel->updSimbodyEngine().getAcceleration(osim_state, body, Vec3(0), accel);
osimModel->updSimbodyEngine().getAngularAcceleration(osim_state, body, angularAccel);
ASSERT_EQUAL(accelerations[i][0], accel[0], 1e-10);
ASSERT_EQUAL(accelerations[i][1], accel[1], 1e-10);
ASSERT_EQUAL(accelerations[i][2], accel[2], 1e-10);
ASSERT_EQUAL(angularAccelerations[i][0], angularAccel[0], 1e-10);
ASSERT_EQUAL(angularAccelerations[i][1], angularAccel[1], 1e-10);
ASSERT_EQUAL(angularAccelerations[i][2], angularAccel[2], 1e-10);
}
}
void testClutchedPathSpring()
{
using namespace SimTK;
// start timing
std::clock_t startTime = std::clock();
double mass = 1;
double stiffness = 100;
double dissipation = 0.3;
double start_h = 0.5;
//double ball_radius = 0.25;
//double omega = sqrt(stiffness/mass);
// Setup OpenSim model
Model* model = new Model;
model->setName("ClutchedPathSpringModel");
model->setGravity(gravity_vec);
//OpenSim bodies
const Ground* ground = &model->getGround();
// body that acts as the pulley that the path wraps over
OpenSim::Body* pulleyBody =
new OpenSim::Body("PulleyBody", mass ,Vec3(0), mass*Inertia::brick(0.1, 0.1, 0.1));
// body the path spring is connected to at both ends
OpenSim::Body* block =
new OpenSim::Body("block", mass ,Vec3(0), mass*Inertia::brick(0.2, 0.1, 0.1));
block->attachGeometry(Brick(Vec3(0.2, 0.1, 0.1)));
block->scale(Vec3(0.2, 0.1, 0.1), false);
//double dh = mass*gravity_vec(1)/stiffness;
WrapCylinder* pulley = new WrapCylinder();
pulley->setRadius(0.1);
pulley->setLength(0.05);
// Add the wrap object to the body, which takes ownership of it
pulleyBody->addWrapObject(pulley);
// Add joints
WeldJoint* weld =
new WeldJoint("weld", *ground, Vec3(0, 1.0, 0), Vec3(0), *pulleyBody, Vec3(0), Vec3(0));
SliderJoint* slider =
new SliderJoint("slider", *ground, Vec3(0), Vec3(0,0,Pi/2),*block, Vec3(0), Vec3(0,0,Pi/2));
double positionRange[2] = {-10, 10};
// Rename coordinates for a slider joint
CoordinateSet &slider_coords = slider->upd_CoordinateSet();
slider_coords[0].setName("block_h");
slider_coords[0].setRange(positionRange);
model->addBody(pulleyBody);
model->addJoint(weld);
model->addBody(block);
model->addJoint(slider);
ClutchedPathSpring* spring =
new ClutchedPathSpring("clutch_spring", stiffness, dissipation, 0.01);
spring->updGeometryPath().appendNewPathPoint("origin", *block, Vec3(-0.1, 0.0 ,0.0));
int N = 10;
for(int i=1; i<N; ++i){
double angle = i*Pi/N;
double x = 0.1*cos(angle);
double y = 0.1*sin(angle);
spring->updGeometryPath().appendNewPathPoint("", *pulleyBody, Vec3(-x, y ,0.0));
}
spring->updGeometryPath().appendNewPathPoint("insertion", *block, Vec3(0.1, 0.0 ,0.0));
// BUG in defining wrapping API requires that the Force containing the GeometryPath be
// connected to the model before the wrap can be added
model->addForce(spring);
PrescribedController* controller = new PrescribedController();
controller->addActuator(*spring);
// Control greater than 1 or less than 0 should be treated as 1 and 0 respectively.
double timePts[4] = {0.0, 5.0, 6.0, 10.0};
double clutchOnPts[4] = {1.5, -2.0, 0.5, 0.5};
PiecewiseConstantFunction* controlfunc =
new PiecewiseConstantFunction(4, timePts, clutchOnPts);
controller->prescribeControlForActuator("clutch_spring", controlfunc);
model->addController(controller);
model->print("ClutchedPathSpringModel.osim");
//Test deserialization
delete model;
model = new Model("ClutchedPathSpringModel.osim");
// Create the force reporter
ForceReporter* reporter = new ForceReporter(model);
model->addAnalysis(reporter);
model->setUseVisualizer(false);
SimTK::State& state = model->initSystem();
CoordinateSet& coords = model->updCoordinateSet();
coords[0].setValue(state, start_h);
model->getMultibodySystem().realize(state, Stage::Position );
//==========================================================================
// Compute the force and torque at the specified times.
RungeKuttaMersonIntegrator integrator(model->getMultibodySystem() );
integrator.setAccuracy(integ_accuracy);
Manager manager(*model, integrator);
manager.setWriteToStorage(true);
manager.setInitialTime(0.0);
double final_t = 4.99999;
manager.setFinalTime(final_t);
manager.integrate(state);
// tension is dynamics dependent because controls must be computed
model->getMultibodySystem().realize(state, Stage::Dynamics);
spring = dynamic_cast<ClutchedPathSpring*>(
&model->updForceSet().get("clutch_spring"));
// Now check that the force reported by spring
double model_force = spring->getTension(state);
double stretch0 = spring->getStretch(state);
// the tension should be half the weight of the block
double analytical_force = -0.5*(gravity_vec(1))*mass;
cout << "Tension is: " << model_force << " and should be: " << analytical_force << endl;
// error if the block does not reach equilibrium since spring is clamped
ASSERT_EQUAL(model_force, analytical_force, 10*integ_accuracy);
// unclamp and continue integrating
manager.setInitialTime(final_t);
final_t = 5.99999;
manager.setFinalTime(final_t);
manager.integrate(state);
// tension is dynamics dependent because controls must be computed
model->getMultibodySystem().realize(state, Stage::Dynamics);
// tension should go to zero quickly
model_force = spring->getTension(state);
cout << "Tension is: " << model_force << " and should be: 0.0" << endl;
// is unclamped and block should be in free-fall
ASSERT_EQUAL(model_force, 0.0, 10*integ_accuracy);
// spring is reclamped at 7s so keep integrating
manager.setInitialTime(final_t);
final_t = 10.0;
manager.setFinalTime(final_t);
manager.integrate(state);
// tension is dynamics dependent because controls must be computed
model->getMultibodySystem().realize(state, Stage::Dynamics);
// tension should build to support the block again
model_force = spring->getTension(state);
double stretch1 = spring->getStretch(state);
cout << "Tension is: " << model_force << " and should be: "<< analytical_force << endl;
// is unclamped and block should be in free-fall
ASSERT_EQUAL(model_force, analytical_force, 10*integ_accuracy);
cout << "Steady stretch at control = 1.0 is " << stretch0 << " m." << endl;
cout << "Steady stretch at control = 0.5 is " << stretch1 << " m." << endl;
ASSERT_EQUAL(2*stretch0, stretch1, 10*integ_accuracy);
manager.getStateStorage().print("clutched_path_spring_states.sto");
model->getControllerSet().printControlStorage("clutched_path_spring_controls.sto");
// Save the forces
reporter->getForceStorage().print("clutched_path_spring_forces.mot");
model->disownAllComponents();
cout << " ********** Test clutched spring time = ********** " <<
1.e3*(std::clock()-startTime)/CLOCKS_PER_SEC << "ms\n" << endl;
}
const SimTK::MobilizedBodyIndex Joint::
getMobilizedBodyIndex(const OpenSim::Body& body) const
{
return body.getMobilizedBodyIndex();
}
/**
* Create a model that does nothing.
*/
int main()
{
try {
///////////////////////////////////////////
// DEFINE BODIES AND JOINTS OF THE MODEL //
///////////////////////////////////////////
// Create an OpenSim model and set its name
Model osimModel;
osimModel.setName("tugOfWar");
// GROUND BODY
// Get a reference to the model's ground body
Ground& ground = osimModel.updGround();
// Add display geometry to the ground to visualize in the GUI
ground.addMeshGeometry("ground.vtp");
ground.addMeshGeometry("anchor1.vtp");
ground.addMeshGeometry("anchor2.vtp");
// BLOCK BODY
// Specify properties of a 20 kg, 0.1 m^3 block body
double blockMass = 20.0, blockSideLength = 0.1;
Vec3 blockMassCenter(0);
Inertia blockInertia = blockMass*Inertia::brick(blockSideLength, blockSideLength, blockSideLength);
// Create a new block body with the specified properties
OpenSim::Body *block = new OpenSim::Body("block", blockMass, blockMassCenter, blockInertia);
// Add display geometry to the block to visualize in the GUI
Brick brick(SimTK::Vec3(0.05, 0.05, 0.05));
block->addGeometry(brick);
// FREE JOINT
// Create a new free joint with 6 degrees-of-freedom (coordinates) between the block and ground bodies
Vec3 locationInParent(0, blockSideLength/2, 0), orientationInParent(0), locationInBody(0), orientationInBody(0);
FreeJoint *blockToGround = new FreeJoint("blockToGround", ground, locationInParent, orientationInParent, *block, locationInBody, orientationInBody);
// Get a reference to the coordinate set (6 degrees-of-freedom) between the block and ground bodies
CoordinateSet& jointCoordinateSet = blockToGround->upd_CoordinateSet();
// Set the angle and position ranges for the coordinate set
double angleRange[2] = {-SimTK::Pi/2, SimTK::Pi/2};
double positionRange[2] = {-1, 1};
jointCoordinateSet[0].setRange(angleRange);
jointCoordinateSet[1].setRange(angleRange);
jointCoordinateSet[2].setRange(angleRange);
jointCoordinateSet[3].setRange(positionRange);
jointCoordinateSet[4].setRange(positionRange);
jointCoordinateSet[5].setRange(positionRange);
// Add the block body to the model
osimModel.addBody(block);
osimModel.addJoint(blockToGround);
///////////////////////////////////////////////
// DEFINE THE SIMULATION START AND END TIMES //
///////////////////////////////////////////////
// Define the initial and final simulation times
double initialTime = 0.0;
double finalTime = 3.00;
/////////////////////////////////////////////
// DEFINE CONSTRAINTS IMPOSED ON THE MODEL //
/////////////////////////////////////////////
// Specify properties of a constant distance constraint to limit the block's motion
double distance = 0.2;
Vec3 pointOnGround(0, blockSideLength/2 ,0);
Vec3 pointOnBlock(0, 0, 0);
// Create a new constant distance constraint
ConstantDistanceConstraint *constDist = new ConstantDistanceConstraint(ground,
pointOnGround, *block, pointOnBlock, distance);
// Add the new point on a line constraint to the model
osimModel.addConstraint(constDist);
///////////////////////////////////////
// DEFINE FORCES ACTING ON THE MODEL //
///////////////////////////////////////
// GRAVITY
// Obtaine the default acceleration due to gravity
Vec3 gravity = osimModel.getGravity();
// MUSCLE FORCES
// Create two new muscles with identical properties
double maxIsometricForce = 1000.0, optimalFiberLength = 0.25, tendonSlackLength = 0.1, pennationAngle = 0.0;
Thelen2003Muscle *muscle1 = new Thelen2003Muscle("muscle1",maxIsometricForce,optimalFiberLength,tendonSlackLength,pennationAngle);
Thelen2003Muscle *muscle2 = new Thelen2003Muscle("muscle2",maxIsometricForce,optimalFiberLength,tendonSlackLength,pennationAngle);
// Specify the paths for the two muscles
// Path for muscle 1
muscle1->addNewPathPoint("muscle1-point1", ground, Vec3(0.0,0.05,-0.35));
muscle1->addNewPathPoint("muscle1-point2", *block, Vec3(0.0,0.0,-0.05));
// Path for muscle 2
muscle2->addNewPathPoint("muscle2-point1", ground, Vec3(0.0,0.05,0.35));
muscle2->addNewPathPoint("muscle2-point2", *block, Vec3(0.0,0.0,0.05));
// Add the two muscles (as forces) to the model
osimModel.addForce(muscle1);
osimModel.addForce(muscle2);
// PRESCRIBED FORCE
// Create a new prescribed force to be applied to the block
PrescribedForce *prescribedForce = new PrescribedForce(block);
prescribedForce->setName("prescribedForce");
// Specify properties of the force function to be applied to the block
double time[2] = {0, finalTime}; // time nodes for linear function
double fXofT[2] = {0, -blockMass*gravity[1]*3.0}; // force values at t1 and t2
// Create linear function for the force components
PiecewiseLinearFunction *forceX = new PiecewiseLinearFunction(2, time, fXofT);
// Set the force and point functions for the new prescribed force
prescribedForce->setForceFunctions(forceX, new Constant(0.0), new Constant(0.0));
prescribedForce->setPointFunctions(new Constant(0.0), new Constant(0.0), new Constant(0.0));
// Add the new prescribed force to the model
osimModel.addForce(prescribedForce);
///////////////////////////////////
// DEFINE CONTROLS FOR THE MODEL //
///////////////////////////////////
// Create a prescribed controller that simply applies controls as function of time
// For muscles, controls are normalized motor-neuron excitations
PrescribedController *muscleController = new PrescribedController();
muscleController->setActuators(osimModel.updActuators());
// Define linear functions for the control values for the two muscles
Array<double> slopeAndIntercept1(0.0, 2); // array of 2 doubles
Array<double> slopeAndIntercept2(0.0, 2);
// muscle1 control has slope of -1 starting 1 at t = 0
slopeAndIntercept1[0] = -1.0/(finalTime-initialTime);
slopeAndIntercept1[1] = 1.0;
// muscle2 control has slope of 0.95 starting 0.05 at t = 0
slopeAndIntercept2[0] = 0.95/(finalTime-initialTime);
slopeAndIntercept2[1] = 0.05;
// Set the indiviudal muscle control functions for the prescribed muscle controller
muscleController->prescribeControlForActuator("muscle1", new LinearFunction(slopeAndIntercept1));
muscleController->prescribeControlForActuator("muscle2", new LinearFunction(slopeAndIntercept2));
// Add the muscle controller to the model
osimModel.addController(muscleController);
///////////////////////////////////
// SPECIFY MODEL DEFAULT STATES //
///////////////////////////////////
// Define the default states for the two muscles
// Activation
muscle1->setDefaultActivation(slopeAndIntercept1[1]);
muscle2->setDefaultActivation(slopeAndIntercept2[1]);
// Fiber length
muscle2->setDefaultFiberLength(optimalFiberLength);
muscle1->setDefaultFiberLength(optimalFiberLength);
// Save the model to a file
osimModel.print("tugOfWar_model.osim");
//////////////////////////
// PERFORM A SIMULATION //
/////////////////////////
//osimModel.setUseVisualizer(true);
// Initialize the system and get the default state
SimTK::State& si = osimModel.initSystem();
// Define non-zero (defaults are 0) states for the free joint
CoordinateSet& modelCoordinateSet = osimModel.updCoordinateSet();
modelCoordinateSet[3].setValue(si, distance); // set x-translation value
modelCoordinateSet[5].setValue(si, 0.0); // set z-translation value
modelCoordinateSet[3].setSpeedValue(si, 0.0); // set x-speed value
double h_start = 0.5;
modelCoordinateSet[4].setValue(si, h_start); // set y-translation which is height
std::cout << "Start height = "<< h_start << std::endl;
osimModel.getMultibodySystem().realize(si, Stage::Velocity);
// Compute initial conditions for muscles
osimModel.equilibrateMuscles(si);
double mfv1 = muscle1->getFiberVelocity(si);
double mfv2 = muscle2->getFiberVelocity(si);
// Create the force reporter for obtaining the forces applied to the model
// during a forward simulation
ForceReporter* reporter = new ForceReporter(&osimModel);
osimModel.addAnalysis(reporter);
// Create the integrator for integrating system dynamics
SimTK::RungeKuttaMersonIntegrator integrator(osimModel.getMultibodySystem());
integrator.setAccuracy(1.0e-6);
// Create the manager managing the forward integration and its outputs
Manager manager(osimModel, integrator);
// Integrate from initial time to final time
manager.setInitialTime(initialTime);
manager.setFinalTime(finalTime);
std::cout<<"\nIntegrating from "<<initialTime<<" to "<<finalTime<<std::endl;
manager.integrate(si);
}
catch (const std::exception& ex)
{
std::cerr << ex.what() << std::endl;
return 1;
}
catch (...)
{
std::cerr << "UNRECOGNIZED EXCEPTION" << std::endl;
return 1;
}
std::cout << "OpenSim environment test completed successfully. You should see a block attached to two muscles visualized in a separate window." << std::endl;
return 0;
}
/**
* Add a body to the SIMM model.
*
* @param aBody The Simbody body that the SimbodySimmBody is based on.
*/
void SimbodySimmModel::addBody(const OpenSim::Body& aBody)
{
SimbodySimmBody* b = new SimbodySimmBody(&aBody, aBody.getName());
_simmBody.append(b);
}
/**
* Method for building the Luxo Jr articulating model. It sets up the system of
* rigid bodies and joint articulations to define Luxo Jr lamp geometry.
*/
void createLuxoJr(OpenSim::Model &model){
// Create base
//--------------
OpenSim::Body* base = new OpenSim::Body("base", baseMass, Vec3(0.0),
Inertia::cylinderAlongY(0.1, baseHeight));
// Add visible geometry
base->attachGeometry(new Mesh("Base_meters.obj"));
// Define base to float relative to ground via free joint
FreeJoint* base_ground = new FreeJoint("base_ground",
// parent body, location in parent body, orientation in parent
model.getGround(), Vec3(0.0), Vec3(0.0),
// child body, location in child body, orientation in child
*base, Vec3(0.0,-baseHeight/2.0,0.0),Vec3(0.0));
// add base to model
model.addBody(base); model.addJoint(base_ground);
/*for (int i = 0; i<base_ground->get_CoordinateSet().getSize(); ++i) {
base_ground->upd_CoordinateSet()[i].set_locked(true);
}*/
// Fix a frame to the base axis for attaching the bottom bracket
SimTK::Transform* shift_and_rotate = new SimTK::Transform();
//shift_and_rotate->setToZero();
shift_and_rotate->set(Rotation(-1*SimTK::Pi/2,
SimTK::CoordinateAxis::XCoordinateAxis()),
Vec3(0.0, bracket_location, 0.0));
PhysicalOffsetFrame pivot_frame_on_base("pivot_frame_on_base",
*base, *shift_and_rotate);
// Create bottom bracket
//-----------------------
OpenSim::Body* bottom_bracket = new OpenSim::Body("bottom_bracket",
bracket_mass, Vec3(0.0),
Inertia::brick(0.03, 0.03, 0.015));
// add bottom bracket to model
model.addBody(bottom_bracket);
// Fix a frame to the bracket for attaching joint
shift_and_rotate->setP(Vec3(0.0));
PhysicalOffsetFrame pivot_frame_on_bottom_bracket(
"pivot_frame_on_bottom_bracket", *bottom_bracket, *shift_and_rotate);
// Add visible geometry
bottom_bracket->attachGeometry(new Mesh("bottom_bracket_meters.obj"));
// Make bottom bracket to twist on base with vertical pin joint.
// You can create a joint from any existing physical frames attached to
// rigid bodies. One way to reference them is by name, like this...
PinJoint* base_pivot = new PinJoint("base_pivot", pivot_frame_on_base,
pivot_frame_on_bottom_bracket);
base_pivot->append_frames(pivot_frame_on_base);
base_pivot->append_frames(pivot_frame_on_bottom_bracket);
// add base pivot joint to the model
model.addJoint(base_pivot);
// add some damping to the pivot
// initialized to zero stiffness and damping
BushingForce* pivotDamper = new BushingForce("pivot_bushing",
"pivot_frame_on_base",
"pivot_frame_on_bottom_bracket");
pivotDamper->set_rotational_damping(pivot_damping);
model.addForce(pivotDamper);
// Create posterior leg
//-----------------------
OpenSim::Body* posteriorLegBar = new OpenSim::Body("posterior_leg_bar",
bar_mass,
Vec3(0.0),
Inertia::brick(leg_bar_dimensions/2.0));
posteriorLegBar->attachGeometry(new Mesh("Leg_meters.obj"));
PhysicalOffsetFrame posterior_knee_on_bottom_bracket(
"posterior_knee_on_bottom_bracket",
*bottom_bracket, Transform(posterior_bracket_hinge_location) );
PhysicalOffsetFrame posterior_knee_on_posterior_bar(
"posterior_knee_on_posterior_bar",
*posteriorLegBar, Transform(inferior_bar_hinge_location) );
// Attach posterior leg to bottom bracket using another pin joint.
// Another way to reference physical frames in a joint is by creating them
// in place, like this...
OpenSim::PinJoint* posteriorKnee = new OpenSim::PinJoint("posterior_knee",
posterior_knee_on_bottom_bracket,
posterior_knee_on_posterior_bar);
// posteriorKnee will own and serialize the attachment offset frames
posteriorKnee->append_frames(posterior_knee_on_bottom_bracket);
posteriorKnee->append_frames(posterior_knee_on_posterior_bar);
// add posterior leg to model
model.addBody(posteriorLegBar); model.addJoint(posteriorKnee);
// allow this joint's coordinate to float freely when assembling constraints
// the joint we create next will drive the pose of the 4-bar linkage
posteriorKnee->upd_CoordinateSet()[0]
.set_is_free_to_satisfy_constraints(true);
// Create anterior leg Hlink
//----------------------------
OpenSim::Body* leg_Hlink = new OpenSim::Body("leg_Hlink",
bar_mass,
Vec3(0.0),
Inertia::brick(leg_Hlink_dimensions/2.0));
leg_Hlink->attachGeometry(new Mesh("H_Piece_meters.obj"));
PhysicalOffsetFrame anterior_knee_on_bottom_bracket(
"anterior_knee_on_bottom_bracket",
*bottom_bracket, Transform(anterior_bracket_hinge_location));
PhysicalOffsetFrame anterior_knee_on_anterior_bar(
"anterior_knee_on_anterior_bar",
*leg_Hlink, Transform(inferior_Hlink_hinge_location));
// Connect anterior leg to bottom bracket via pin joint
OpenSim::PinJoint* anterior_knee = new OpenSim::PinJoint("anterior_knee",
anterior_knee_on_bottom_bracket,
anterior_knee_on_anterior_bar);
anterior_knee->append_frames(anterior_knee_on_bottom_bracket);
anterior_knee->append_frames(anterior_knee_on_anterior_bar);
// add anterior leg to model
model.addBody(leg_Hlink); model.addJoint(anterior_knee);
// this anterior knee joint defines the motion of the lower 4-bar linkage
// set it's default coordinate value to a slightly flexed position.
anterior_knee->upd_CoordinateSet()[0].set_default_value(SimTK::Pi/6);
// Create pelvis bracket
//-----------------------
OpenSim::Body* pelvisBracket = new OpenSim::Body("pelvis_bracket",
bracket_mass,
Vec3(0.0),
Inertia::brick(pelvis_dimensions/2.0));
pelvisBracket->attachGeometry(new Mesh("Pelvis_bracket_meters.obj"));
// Connect pelvis to Hlink via pin joint
SimTK::Transform pelvis_anterior_shift(
anterior_superior_pelvis_pin_location);
PhysicalOffsetFrame anterior_hip_on_Hlink(
"anterior_hip_on_Hlink",
*leg_Hlink, Transform(superior_Hlink_hinge_location));
PhysicalOffsetFrame anterior_hip_on_pelvis(
"anterior_hip_on_pelvis",
*pelvisBracket, pelvis_anterior_shift);
OpenSim::PinJoint* anteriorHip = new OpenSim::PinJoint("anterior_hip",
anterior_hip_on_Hlink,
anterior_hip_on_pelvis);
anteriorHip->append_frames(anterior_hip_on_Hlink);
anteriorHip->append_frames(anterior_hip_on_pelvis);
// add anterior leg to model
model.addBody(pelvisBracket); model.addJoint(anteriorHip);
// since the previous, anterior knee joint drives the pose of the lower
// 4-bar linkage, set the anterior hip angle such that it's free to satisfy
// constraints that couple it to the 4-bar linkage.
anteriorHip->upd_CoordinateSet()[0]
.set_is_free_to_satisfy_constraints(true);
// Close the loop for the lower, four-bar linkage with a constraint
//------------------------------------------------------------------
// Create and configure point on line constraint
OpenSim::PointOnLineConstraint* posteriorHip =
new OpenSim::PointOnLineConstraint();
posteriorHip->setLineBodyByName(pelvisBracket->getName());
posteriorHip->setLineDirection(Vec3(0.0,0.0,1.0));
posteriorHip->setPointOnLine(inferior_pelvis_pin_location);
posteriorHip->setFollowerBodyByName(posteriorLegBar->getName());
posteriorHip->setPointOnFollower(superior_bar_hinge_location);
// add constraint to model
model.addConstraint(posteriorHip);
// Create chest piece
//-----------------------
OpenSim::Body* chest = new OpenSim::Body("chest_bar", bar_mass,
Vec3(0.0),
Inertia::brick(torso_bar_dimensions/2.0));
chest->attachGeometry(new Mesh("Anterior_torso_bar.obj"));
PhysicalOffsetFrame anterior_torso_hinge_on_pelvis(
"anterior_torso_hinge_on_pelvis",
*pelvisBracket, Transform(anterior_superior_pelvis_pin_location) );
PhysicalOffsetFrame anterior_torso_hinge_on_chest(
"anterior_torso_hinge_on_chest",
*chest, Transform(inferior_torso_hinge_location) );
// Attach chest piece to pelvice with pin joint
OpenSim::PinJoint* anteriorTorsoHinge = new OpenSim::PinJoint(
"anterior_torso_hinge",
anterior_torso_hinge_on_pelvis,
anterior_torso_hinge_on_chest);
anteriorTorsoHinge->append_frames(anterior_torso_hinge_on_pelvis);
anteriorTorsoHinge->append_frames(anterior_torso_hinge_on_chest);
// add posterior leg to model
model.addBody(chest); model.addJoint(anteriorTorsoHinge);
// set torso rotation slightly anterior
anteriorTorsoHinge->upd_CoordinateSet()[0].setDefaultValue(-1*SimTK::Pi/4);
// Create chest piece
//-----------------------
OpenSim::Body* back = new OpenSim::Body("back_bar", bar_mass,
Vec3(0.0),
Inertia::brick(torso_bar_dimensions/2.0));
back->attachGeometry(new Mesh("Posterior_torso_bar.obj"));
PhysicalOffsetFrame posterior_torso_hinge_on_pelvis(
"posterior_torso_hinge_on_pelvis",
*pelvisBracket, Transform(posterior_superior_pelvis_pin_location) );
PhysicalOffsetFrame posterior_torso_hinge_on_back(
"posterior_torso_hinge_on_back",
*back, Transform(back_peg_center) );
// Attach chest piece to pelvis with pin joint
OpenSim::PinJoint* posteriorTorsoHinge = new OpenSim::PinJoint(
"posterior_torso_hinge",
posterior_torso_hinge_on_pelvis,
posterior_torso_hinge_on_back);
posteriorTorsoHinge->append_frames(posterior_torso_hinge_on_pelvis);
posteriorTorsoHinge->append_frames(posterior_torso_hinge_on_back);
// add posterior leg to model
model.addBody(back); model.addJoint(posteriorTorsoHinge);
// set posterior back joint to freely follow anterior joint through 4-bar
// linkage coupling.
posteriorTorsoHinge->upd_CoordinateSet()[0]
.set_is_free_to_satisfy_constraints(true);
// Create shoulder bracket
//-----------------------
OpenSim::Body* shoulderBracket = new OpenSim::Body("shoulder_bracket",
bracket_mass,
Vec3(0.0),
Inertia::brick(shoulder_dimensions/2.0));
shoulderBracket->attachGeometry(new Mesh("Shoulder_meters.obj"));
// add anterior leg to model
model.addBody(shoulderBracket);
PhysicalOffsetFrame anterior_thoracic_joint_on_chest(
"anterior_thoracic_joint_on_chest",
*chest, Transform(superior_torso_hinge_location) );
PhysicalOffsetFrame anterior_thoracic_joint_on_shoulder(
"anterior_thoracic_joint_on_shoulder",
*shoulderBracket, Transform(anterior_thoracic_joint_center));
// Connect pelvis to Hlink via pin joint
OpenSim::PinJoint* anteriorThoracicJoint =
new OpenSim::PinJoint("anterior_thoracic_joint",
anterior_thoracic_joint_on_chest,
anterior_thoracic_joint_on_shoulder);
anteriorThoracicJoint->append_frames(anterior_thoracic_joint_on_chest);
anteriorThoracicJoint->append_frames(anterior_thoracic_joint_on_shoulder);
// add back joint
model.addJoint(anteriorThoracicJoint);
// since the previous, anterior thoracic joint drives the pose of the lower
// 4-bar linkage, set the anterior shoulder angle such that it's free to
// satisfy constraints that couple it to the 4-bar linkage.
anteriorThoracicJoint->upd_CoordinateSet()[0]
.set_is_free_to_satisfy_constraints(true);
// Close the loop for the lower, four-bar linkage with a constraint
//------------------------------------------------------------------
// Create and configure point on line constraint
OpenSim::PointOnLineConstraint* posteriorShoulder =
new OpenSim::PointOnLineConstraint();
posteriorShoulder->setLineBodyByName(shoulderBracket->getName());
posteriorShoulder->setLineDirection(Vec3(0.0,0.0,1.0));
posteriorShoulder->setPointOnLine(posterior_thoracic_joint_center);
posteriorShoulder->setFollowerBodyByName(back->getName());
posteriorShoulder->setPointOnFollower(superior_torso_hinge_location);
// add constraint to model
model.addConstraint(posteriorShoulder);
// Create and add luxo head
OpenSim::Body* head = new OpenSim::Body("head", head_mass, Vec3(0),
Inertia::cylinderAlongX(0.5*head_dimension[1], head_dimension[1]));
head->attachGeometry(new Mesh("luxo_head_meters.obj"));
head->attachGeometry(new Mesh("Bulb_meters.obj"));
model.addBody(head);
PhysicalOffsetFrame cervical_joint_on_shoulder("cervical_joint_on_shoulder",
*shoulderBracket, Transform(superior_shoulder_hinge_location) );
PhysicalOffsetFrame cervical_joint_on_head("cervical_joint_on_head",
*head, Transform(cervicle_joint_center));
// attach to shoulder via pin joint
OpenSim::PinJoint* cervicalJoint = new OpenSim::PinJoint("cervical_joint",
cervical_joint_on_shoulder,
cervical_joint_on_head);
cervicalJoint->append_frames(cervical_joint_on_shoulder);
cervicalJoint->append_frames(cervical_joint_on_head);
// add a neck joint
model.addJoint(cervicalJoint);
// lock the kneck coordinate so the head doens't spin without actuators or
// passive forces
cervicalJoint->upd_CoordinateSet()[0].set_locked(true);
// Coordinate Limit forces for restricting leg range of motion.
//-----------------------------------------------------------------------
CoordinateLimitForce* kneeLimitForce =
new CoordinateLimitForce(
anterior_knee->get_CoordinateSet()[0].getName(),
knee_flexion_max, joint_softstop_stiffness,
knee_flexion_min, joint_softstop_stiffness,
joint_softstop_damping,
transition_region);
model.addForce(kneeLimitForce);
// Coordinate Limit forces for restricting back range motion.
//-----------------------------------------------------------------------
CoordinateLimitForce* backLimitForce =
new CoordinateLimitForce(
anteriorTorsoHinge->get_CoordinateSet()[0].getName(),
back_extension_max, joint_softstop_stiffness,
back_extension_min, joint_softstop_stiffness,
joint_softstop_damping,
transition_region);
model.addForce(backLimitForce);
// Contact
//-----------------------------------------------------------------------
ContactHalfSpace* floor_surface = new ContactHalfSpace(SimTK::Vec3(0),
SimTK::Vec3(0, 0, -0.5*SimTK::Pi),
model.updGround(), "floor_surface");
OpenSim::ContactMesh* foot_surface = new ContactMesh(
"thin_disc_0.11_by_0.01_meters.obj",
SimTK::Vec3(0),
SimTK::Vec3(0),
*base,
"foot_surface");
// add contact geometry to model
model.addContactGeometry(floor_surface);
model.addContactGeometry(foot_surface);
// define contact as an elastic foundation force
OpenSim::ElasticFoundationForce::ContactParameters* contactParameters =
new OpenSim::ElasticFoundationForce::ContactParameters(
stiffness,
dissipation,
friction,
friction,
viscosity);
contactParameters->addGeometry("foot_surface");
contactParameters->addGeometry("floor_surface");
OpenSim::ElasticFoundationForce* contactForce =
new OpenSim::ElasticFoundationForce(contactParameters);
contactForce->setName("contact_force");
model.addForce(contactForce);
// MUSCLES
//-----------------------------------------------------------------------
// add a knee extensor to control the lower 4-bar linkage
Millard2012EquilibriumMuscle* kneeExtensorRight = new Millard2012EquilibriumMuscle(
"knee_extensor_right",
knee_extensor_F0, knee_extensor_lm0,
knee_extensor_lts, pennationAngle);
kneeExtensorRight->addNewPathPoint("knee_extensor_right_origin", *leg_Hlink,
knee_extensor_origin);
kneeExtensorRight->addNewPathPoint("knee_extensor_right_insertion",
*bottom_bracket,
knee_extensor_insertion);
kneeExtensorRight->set_ignore_tendon_compliance(true);
model.addForce(kneeExtensorRight);
// add a second copy of this knee extensor for the left side
Millard2012EquilibriumMuscle* kneeExtensorLeft =
new Millard2012EquilibriumMuscle(*kneeExtensorRight);
kneeExtensorLeft->setName("kneeExtensorLeft");
// flip the z coordinates of all path points
PathPointSet& points = kneeExtensorLeft->updGeometryPath().updPathPointSet();
for (int i=0; i<points.getSize(); ++i) {
points[i].setLocationCoord(2, -1*points[i].getLocationCoord(2));
}
kneeExtensorLeft->set_ignore_tendon_compliance(true);
model.addForce(kneeExtensorLeft);
// add a back extensor to controll the upper 4-bar linkage
Millard2012EquilibriumMuscle* backExtensorRight = new Millard2012EquilibriumMuscle(
"back_extensor_right",
back_extensor_F0, back_extensor_lm0,
back_extensor_lts, pennationAngle);
backExtensorRight->addNewPathPoint("back_extensor_right_origin", *chest,
back_extensor_origin);
backExtensorRight->addNewPathPoint("back_extensor_right_insertion", *back,
back_extensor_insertion);
backExtensorRight->set_ignore_tendon_compliance(true);
model.addForce(backExtensorRight);
// copy right back extensor and use to make left extensor
Millard2012EquilibriumMuscle* backExtensorLeft =
new Millard2012EquilibriumMuscle(*backExtensorRight);
backExtensorLeft->setName("back_extensor_left");
PathPointSet& pointsLeft = backExtensorLeft->updGeometryPath()
.updPathPointSet();
for (int i=0; i<points.getSize(); ++i) {
pointsLeft[i].setLocationCoord(2, -1*pointsLeft[i].getLocationCoord(2));
}
backExtensorLeft->set_ignore_tendon_compliance(true);
model.addForce(backExtensorLeft);
// MUSCLE CONTROLLERS
//________________________________________________________________________
// specify a piecwise linear function for the muscle excitations
PiecewiseConstantFunction* x_of_t = new PiecewiseConstantFunction(3, times,
excitations);
PrescribedController* kneeController = new PrescribedController();
kneeController->addActuator(*kneeExtensorLeft);
kneeController->addActuator(*kneeExtensorRight);
kneeController->prescribeControlForActuator(0, x_of_t);
kneeController->prescribeControlForActuator(1, x_of_t->clone());
model.addController(kneeController);
PrescribedController* backController = new PrescribedController();
backController->addActuator(*backExtensorLeft);
backController->addActuator(*backExtensorRight);
backController->prescribeControlForActuator(0, x_of_t->clone());
backController->prescribeControlForActuator(1, x_of_t->clone());
model.addController(backController);
/* You'll find that these muscles can make Luxo Myo stand, but not jump.
* Jumping will require an assistive device. We'll add two frames for
* attaching a point to point assistive actuator.
*/
// add frames for connecting a back assitance device between the chest
// and pelvis
PhysicalOffsetFrame* back_assist_origin_frame = new
PhysicalOffsetFrame("back_assist_origin",
*chest,
back_assist_origin_transform);
PhysicalOffsetFrame* back_assist_insertion_frame = new
PhysicalOffsetFrame("back_assist_insertion",
*pelvisBracket,
back_assist_insertion_transform);
model.addFrame(back_assist_origin_frame);
model.addFrame(back_assist_insertion_frame);
// add frames for connecting a knee assistance device between the posterior
// leg and bottom bracket.
PhysicalOffsetFrame* knee_assist_origin_frame = new
PhysicalOffsetFrame("knee_assist_origin",
*posteriorLegBar,
knee_assist_origin_transform);
PhysicalOffsetFrame* knee_assist_insertion_frame = new
PhysicalOffsetFrame("knee_assist_insertion",
*bottom_bracket,
knee_assist_insertion_transform);
model.addFrame(knee_assist_origin_frame);
model.addFrame(knee_assist_insertion_frame);
// Temporary: make the frame geometry disappear.
for (auto& c : model.getComponentList<OpenSim::FrameGeometry>()) {
const_cast<OpenSim::FrameGeometry*>(&c)->set_scale_factors(
SimTK::Vec3(0.001, 0.001, 0.001));
}
}
//-----------------------------------------------------------------------------
// METHODS TO APPLY FORCES AND TORQUES
//-----------------------------------------------------------------------------
void Force::applyForceToPoint(const SimTK::State &s, const OpenSim::Body &aBody, const Vec3& aPoint,
const Vec3& aForce, Vector_<SpatialVec> &bodyForces) const
{
_model->getMatterSubsystem().addInStationForce(s, SimTK::MobilizedBodyIndex(aBody.getIndex()),
aPoint, aForce, bodyForces);
}
void Force::applyTorque(const SimTK::State &s, const OpenSim::Body &aBody,
const Vec3& aTorque, Vector_<SpatialVec> &bodyForces) const
{
_model->getMatterSubsystem().addInBodyTorque(s, SimTK::MobilizedBodyIndex(aBody.getIndex()),
aTorque, bodyForces);
}
/**
* Run a simulation of block sliding with contact on by two muscles sliding with contact
*/
int main()
{
clock_t startTime = clock();
try {
//////////////////////
// MODEL PARAMETERS //
//////////////////////
// Specify body mass of a 20 kg, 0.1m sides of cubed block body
double blockMass = 20.0, blockSideLength = 0.1;
// Constant distance of constraint to limit the block's motion
double constantDistance = 0.2;
// Contact parameters
double stiffness = 1.0e7, dissipation = 0.1, friction = 0.2, viscosity=0.01;
///////////////////////////////////////////
// DEFINE BODIES AND JOINTS OF THE MODEL //
///////////////////////////////////////////
// Create an OpenSim model and set its name
Model osimModel;
osimModel.setName("tugOfWar");
// GROUND BODY
// Get a reference to the model's ground body
OpenSim::Body& ground = osimModel.getGroundBody();
// Add display geometry to the ground to visualize in the Visualizer and GUI
// add a checkered floor
ground.addDisplayGeometry("checkered_floor.vtp");
// add anchors for the muscles to be fixed too
ground.addDisplayGeometry("block.vtp");
ground.addDisplayGeometry("block.vtp");
// block is 0.1 by 0.1 by 0.1m cube and centered at origin.
// transform anchors to be placed at the two extremes of the sliding block (to come)
GeometrySet& geometry = ground.updDisplayer()->updGeometrySet();
DisplayGeometry& anchor1 = geometry[1];
DisplayGeometry& anchor2 = geometry[2];
// scale the anchors
anchor1.setScaleFactors(Vec3(5, 1, 1));
anchor2.setScaleFactors(Vec3(5, 1, 1));
// reposition the anchors
anchor1.setTransform(Transform(Vec3(0, 0.05, 0.35)));
anchor2.setTransform(Transform(Vec3(0, 0.05, -0.35)));
// BLOCK BODY
Vec3 blockMassCenter(0);
Inertia blockInertia = blockMass*Inertia::brick(blockSideLength, blockSideLength, blockSideLength);
// Create a new block body with the specified properties
OpenSim::Body *block = new OpenSim::Body("block", blockMass, blockMassCenter, blockInertia);
// Add display geometry to the block to visualize in the GUI
block->addDisplayGeometry("block.vtp");
// FREE JOINT
// Create a new free joint with 6 degrees-of-freedom (coordinates) between the block and ground bodies
Vec3 locationInParent(0, blockSideLength/2, 0), orientationInParent(0), locationInBody(0), orientationInBody(0);
FreeJoint *blockToGround = new FreeJoint("blockToGround", ground, locationInParent, orientationInParent, *block, locationInBody, orientationInBody);
// Get a reference to the coordinate set (6 degrees-of-freedom) between the block and ground bodies
CoordinateSet& jointCoordinateSet = blockToGround->upd_CoordinateSet();
// Set the angle and position ranges for the coordinate set
double angleRange[2] = {-SimTK::Pi/2, SimTK::Pi/2};
double positionRange[2] = {-1, 1};
jointCoordinateSet[0].setRange(angleRange);
jointCoordinateSet[1].setRange(angleRange);
jointCoordinateSet[2].setRange(angleRange);
jointCoordinateSet[3].setRange(positionRange);
jointCoordinateSet[4].setRange(positionRange);
jointCoordinateSet[5].setRange(positionRange);
// GRAVITY
// Obtaine the default acceleration due to gravity
Vec3 gravity = osimModel.getGravity();
// Define non-zero default states for the free joint
jointCoordinateSet[3].setDefaultValue(constantDistance); // set x-translation value
double h_start = blockMass*gravity[1]/(stiffness*blockSideLength*blockSideLength);
jointCoordinateSet[4].setDefaultValue(h_start); // set y-translation which is height
// Add the block and joint to the model
osimModel.addBody(block);
osimModel.addJoint(blockToGround);
///////////////////////////////////////////////
// DEFINE THE SIMULATION START AND END TIMES //
///////////////////////////////////////////////
// Define the initial and final simulation times
double initialTime = 0.0;
double finalTime = 3.00;
/////////////////////////////////////////////
// DEFINE CONSTRAINTS IMPOSED ON THE MODEL //
/////////////////////////////////////////////
Vec3 pointOnGround(0, blockSideLength/2 ,0);
Vec3 pointOnBlock(0, 0, 0);
// Create a new constant distance constraint
ConstantDistanceConstraint *constDist =
new ConstantDistanceConstraint(ground,
pointOnGround, *block, pointOnBlock, constantDistance);
// Add the new point on a line constraint to the model
osimModel.addConstraint(constDist);
///////////////////////////////////////
// DEFINE FORCES ACTING ON THE MODEL //
///////////////////////////////////////
// MUSCLE FORCES
// Create two new muscles with identical properties
double maxIsometricForce = 1000.0, optimalFiberLength = 0.25, tendonSlackLength = 0.1, pennationAngle = 0.0;
Thelen2003Muscle *muscle1 = new Thelen2003Muscle("muscle1",maxIsometricForce,optimalFiberLength,tendonSlackLength,pennationAngle);
Thelen2003Muscle *muscle2 = new Thelen2003Muscle("muscle2",maxIsometricForce,optimalFiberLength,tendonSlackLength,pennationAngle);
// Specify the paths for the two muscles
// Path for muscle 1
muscle1->addNewPathPoint("muscle1-point1", ground, Vec3(0.0,0.05,-0.35));
muscle1->addNewPathPoint("muscle1-point2", *block, Vec3(0.0,0.0,-0.05));
// Path for muscle 2
muscle2->addNewPathPoint("muscle2-point1", ground, Vec3(0.0,0.05,0.35));
muscle2->addNewPathPoint("muscle2-point2", *block, Vec3(0.0,0.0,0.05));
// Add the two muscles (as forces) to the model
osimModel.addForce(muscle1);
osimModel.addForce(muscle2);
// CONTACT FORCE
// Define contact geometry
// Create new floor contact halfspace
ContactHalfSpace *floor = new ContactHalfSpace(SimTK::Vec3(0), SimTK::Vec3(0, 0, -0.5*SimTK_PI), ground, "floor");
// Create new cube contact mesh
OpenSim::ContactMesh *cube = new OpenSim::ContactMesh("blockMesh.obj", SimTK::Vec3(0), SimTK::Vec3(0), *block, "cube");
// Add contact geometry to the model
osimModel.addContactGeometry(floor);
osimModel.addContactGeometry(cube);
// Define contact parameters for elastic foundation force
OpenSim::ElasticFoundationForce::ContactParameters *contactParams =
new OpenSim::ElasticFoundationForce::ContactParameters(stiffness, dissipation, friction, friction, viscosity);
contactParams->addGeometry("cube");
contactParams->addGeometry("floor");
// Create a new elastic foundation (contact) force between the floor and cube.
OpenSim::ElasticFoundationForce *contactForce = new OpenSim::ElasticFoundationForce(contactParams);
contactForce->setName("contactForce");
// Add the new elastic foundation force to the model
osimModel.addForce(contactForce);
// PRESCRIBED FORCE
// Create a new prescribed force to be applied to the block
PrescribedForce *prescribedForce = new PrescribedForce(block);
prescribedForce->setName("prescribedForce");
// Specify properties of the force function to be applied to the block
double time[2] = {0, finalTime}; // time nodes for linear function
double fXofT[2] = {0, -blockMass*gravity[1]*3.0}; // force values at t1 and t2
// Create linear function for the force components
PiecewiseLinearFunction *forceX = new PiecewiseLinearFunction(2, time, fXofT);
// Set the force and point functions for the new prescribed force
prescribedForce->setForceFunctions(forceX, new Constant(0.0), new Constant(0.0));
prescribedForce->setPointFunctions(new Constant(0.0), new Constant(0.0), new Constant(0.0));
// Add the new prescribed force to the model
osimModel.addForce(prescribedForce);
///////////////////////////////////
// DEFINE CONTROLS FOR THE MODEL //
///////////////////////////////////
// Create a prescribed controller that simply applies controls as function of time
// For muscles, controls are normalized motor-neuron excitations
PrescribedController *muscleController = new PrescribedController();
muscleController->setActuators(osimModel.updActuators());
// Define linear functions for the control values for the two muscles
Array<double> slopeAndIntercept1(0.0, 2); // array of 2 doubles
Array<double> slopeAndIntercept2(0.0, 2);
// muscle1 control has slope of -1 starting 1 at t = 0
slopeAndIntercept1[0] = -1.0/(finalTime-initialTime); slopeAndIntercept1[1] = 1.0;
// muscle2 control has slope of 0.95 starting 0.05 at t = 0
slopeAndIntercept2[0] = 0.95/(finalTime-initialTime); slopeAndIntercept2[1] = 0.05;
// Set the indiviudal muscle control functions for the prescribed muscle controller
muscleController->prescribeControlForActuator("muscle1", new LinearFunction(slopeAndIntercept1));
muscleController->prescribeControlForActuator("muscle2", new LinearFunction(slopeAndIntercept2));
// Add the muscle controller to the model
osimModel.addController(muscleController);
///////////////////////////////////
// SPECIFY MODEL DEFAULT STATES //
///////////////////////////////////
// Define the default states for the two muscles
// Activation
muscle1->setDefaultActivation(slopeAndIntercept1[1]);
muscle2->setDefaultActivation(slopeAndIntercept2[1]);
// Fiber length
muscle2->setDefaultFiberLength(optimalFiberLength);
muscle1->setDefaultFiberLength(optimalFiberLength);
// Save the model to a file
osimModel.print("tugOfWar_model.osim");
//////////////////////////
// PERFORM A SIMULATION //
//////////////////////////
// set use visualizer to true to visualize the simulation live
osimModel.setUseVisualizer(false);
// Initialize the system and get the default state
SimTK::State& si = osimModel.initSystem();
// Enable constraint consistent with current configuration of the model
constDist->setDisabled(si, false);
cout << "Start height = "<< h_start << endl;
osimModel.getMultibodySystem().realize(si, Stage::Velocity);
// Compute initial conditions for muscles
osimModel.equilibrateMuscles(si);
double mfv1 = muscle1->getFiberVelocity(si);
double mfv2 = muscle2->getFiberVelocity(si);
// Create the force reporter for obtaining the forces applied to the model
// during a forward simulation
ForceReporter* reporter = new ForceReporter(&osimModel);
osimModel.addAnalysis(reporter);
// Create the integrator for integrating system dynamics
SimTK::RungeKuttaMersonIntegrator integrator(osimModel.getMultibodySystem());
integrator.setAccuracy(1.0e-6);
// Create the manager managing the forward integration and its outputs
Manager manager(osimModel, integrator);
// Print out details of the model
osimModel.printDetailedInfo(si, cout);
// Integrate from initial time to final time
manager.setInitialTime(initialTime);
manager.setFinalTime(finalTime);
cout<<"\nIntegrating from "<<initialTime<<" to "<<finalTime<<endl;
manager.integrate(si);
//////////////////////////////
// SAVE THE RESULTS TO FILE //
//////////////////////////////
// Save the model states from forward integration
Storage statesDegrees(manager.getStateStorage());
statesDegrees.print("tugOfWar_states.sto");
// Save the forces
reporter->getForceStorage().print("tugOfWar_forces.mot");
}
catch (const std::exception& ex)
{
cerr << ex.what() << endl;
return 1;
}
catch (...)
{
cerr << "UNRECOGNIZED EXCEPTION" << endl;
return 1;
}
cout << "main() routine time = " << 1.e3*(clock()-startTime)/CLOCKS_PER_SEC << "ms\n";
cout << "OpenSim example completed successfully." << endl;
return 0;
}
//==========================================================================================================
// Test Cases
//==========================================================================================================
int testBouncingBall(bool useMesh)
{
// Setup OpenSim model
Model *osimModel = new Model;
//OpenSim bodies
OpenSim::Body& ground = *new OpenSim::Body("ground", SimTK::Infinity,
Vec3(0), Inertia());
osimModel->addBody(&ground);
OpenSim::Body ball;
ball.setName("ball");
ball.set_mass(mass);
ball.set_mass_center(Vec3(0));
ball.setInertia(Inertia(1.0));
// Add joints
FreeJoint free("free", ground, Vec3(0), Vec3(0), ball, Vec3(0), Vec3(0));
osimModel->addBody(&ball);
osimModel->addJoint(&free);
// Create ContactGeometry.
ContactHalfSpace *floor = new ContactHalfSpace(Vec3(0), Vec3(0, 0, -0.5*SimTK_PI), ground, "ground");
osimModel->addContactGeometry(floor);
OpenSim::ContactGeometry* geometry;
if (useMesh)
geometry = new ContactMesh(mesh_file, Vec3(0), Vec3(0), ball, "ball");
else
geometry = new ContactSphere(radius, Vec3(0), ball, "ball");
osimModel->addContactGeometry(geometry);
OpenSim::Force* force;
if (useMesh)
{
// Add an ElasticFoundationForce.
OpenSim::ElasticFoundationForce::ContactParameters* contactParams = new OpenSim::ElasticFoundationForce::ContactParameters(1.0e6/radius, 1e-5, 0.0, 0.0, 0.0);
contactParams->addGeometry("ball");
contactParams->addGeometry("ground");
force = new OpenSim::ElasticFoundationForce(contactParams);
osimModel->addForce(force);
}
else
{
// Add a HuntCrossleyForce.
OpenSim::HuntCrossleyForce::ContactParameters* contactParams = new OpenSim::HuntCrossleyForce::ContactParameters(1.0e6, 1e-5, 0.0, 0.0, 0.0);
contactParams->addGeometry("ball");
contactParams->addGeometry("ground");
force = new OpenSim::HuntCrossleyForce(contactParams);
osimModel->addForce(force);
}
osimModel->setGravity(gravity_vec);
osimModel->setName("TestContactGeomtery_Ball");
osimModel->clone()->print("TestContactGeomtery_Ball.osim");
Kinematics* kin = new Kinematics(osimModel);
osimModel->addAnalysis(kin);
SimTK::State& osim_state = osimModel->initSystem();
osim_state.updQ()[4] = height;
osimModel->getMultibodySystem().realize(osim_state, Stage::Position );
//Initial system energy is all potential
double Etot_orig = mass*(-gravity_vec[1])*height;
//==========================================================================================================
// Simulate it and see if it bounces correctly.
cout << "stateY=" << osim_state.getY() << std::endl;
RungeKuttaMersonIntegrator integrator(osimModel->getMultibodySystem() );
integrator.setAccuracy(integ_accuracy);
Manager manager(*osimModel, integrator);
for (unsigned int i = 0; i < duration/interval; ++i)
{
manager.setInitialTime(i*interval);
manager.setFinalTime((i+1)*interval);
manager.integrate(osim_state);
double time = osim_state.getTime();
osimModel->getMultibodySystem().realize(osim_state, Stage::Acceleration);
Vec3 pos, vel;
osimModel->updSimbodyEngine().getPosition(osim_state, osimModel->getBodySet().get("ball"), Vec3(0), pos);
osimModel->updSimbodyEngine().getVelocity(osim_state, osimModel->getBodySet().get("ball"), Vec3(0), vel);
double Etot = mass*((-gravity_vec[1])*pos[1] + 0.5*vel[1]*vel[1]);
//cout << "starting system energy = " << Etot_orig << " versus current energy = " << Etot << endl;
// contact absorbs and returns energy so make sure not in contact
if (pos[1] > 2*radius)
{
ASSERT_EQUAL(Etot_orig, Etot, 1e-2, __FILE__, __LINE__, "Bouncing ball on plane Failed: energy was not conserved.");
}
else
{
cout << "In contact at time = " << time << endl;
ASSERT(pos[1] < 5.0 && pos[1] > 0);
}
ASSERT_EQUAL(0.0, pos[0], 1e-4);
ASSERT_EQUAL(0.0, pos[2], 1e-4);
ASSERT_EQUAL(0.0, vel[0], 1e-3);
ASSERT_EQUAL(0.0, vel[2], 1e-3);
}
std::string prefix = useMesh?"Kinematics_Mesh":"Kinematics_NoMesh";
kin->printResults(prefix);
osimModel->disownAllComponents();
// model takes ownership of components unless container set is told otherwise
delete osimModel;
return 0;
}
// test sphere to sphere contact using elastic foundation with and without
// meshes and their combination
int testBallToBallContact(bool useElasticFoundation, bool useMesh1, bool useMesh2)
{
// Setup OpenSim model
Model *osimModel = new Model;
//OpenSim bodies
OpenSim::Body& ground = *new OpenSim::Body("ground", SimTK::Infinity,
Vec3(0), Inertia());
osimModel->addBody(&ground);
OpenSim::Body ball;
ball.setName("ball");
ball.setMass(mass);
ball.setMassCenter(Vec3(0));
ball.setInertia(Inertia(1.0));
// Add joints
FreeJoint free("free", ground, Vec3(0), Vec3(0), ball, Vec3(0), Vec3(0));
osimModel->addBody(&ball);
osimModel->addJoint(&free);
// Create ContactGeometry.
OpenSim::ContactGeometry *ball1, *ball2;
if (useElasticFoundation && useMesh1)
ball1 = new ContactMesh(mesh_file, Vec3(0), Vec3(0), ground, "ball1");
else
ball1 = new ContactSphere(radius, Vec3(0), ground, "ball1");
if (useElasticFoundation && useMesh2)
ball2 = new ContactMesh(mesh_file, Vec3(0), Vec3(0), ball, "ball2");
else
ball2 = new ContactSphere(radius, Vec3(0), ball, "ball2");
osimModel->addContactGeometry(ball1);
osimModel->addContactGeometry(ball2);
OpenSim::Force* force;
std::string prefix;
if (useElasticFoundation){
}
else{
}
if (useElasticFoundation)
{
// Add an ElasticFoundationForce.
OpenSim::ElasticFoundationForce::ContactParameters* contactParams = new OpenSim::ElasticFoundationForce::ContactParameters(1.0e6/(2*radius), 0.001, 0.0, 0.0, 0.0);
contactParams->addGeometry("ball1");
contactParams->addGeometry("ball2");
force = new OpenSim::ElasticFoundationForce(contactParams);
prefix = "EF_";
prefix += useMesh1 ?"Mesh":"noMesh";
prefix += useMesh2 ? "_to_Mesh":"_to_noMesh";
}
else
{
// Add a Hertz HuntCrossleyForce.
OpenSim::HuntCrossleyForce::ContactParameters* contactParams = new OpenSim::HuntCrossleyForce::ContactParameters(1.0e6, 0.001, 0.0, 0.0, 0.0);
contactParams->addGeometry("ball1");
contactParams->addGeometry("ball2");
force = new OpenSim::HuntCrossleyForce(contactParams);
prefix = "Hertz";
}
force->setName("contact");
osimModel->addForce(force);
osimModel->setGravity(gravity_vec);
osimModel->setName(prefix);
osimModel->clone()->print(prefix+".osim");
Kinematics* kin = new Kinematics(osimModel);
osimModel->addAnalysis(kin);
ForceReporter* reporter = new ForceReporter(osimModel);
osimModel->addAnalysis(reporter);
SimTK::State& osim_state = osimModel->initSystem();
osim_state.updQ()[4] = height;
osimModel->getMultibodySystem().realize(osim_state, Stage::Position );
//==========================================================================================================
// Simulate it and see if it bounces correctly.
cout << "stateY=" << osim_state.getY() << std::endl;
RungeKuttaMersonIntegrator integrator(osimModel->getMultibodySystem() );
integrator.setAccuracy(integ_accuracy);
integrator.setMaximumStepSize(100*integ_accuracy);
Manager manager(*osimModel, integrator);
manager.setInitialTime(0.0);
manager.setFinalTime(duration);
manager.integrate(osim_state);
kin->printResults(prefix);
reporter->printResults(prefix);
osimModel->disownAllComponents();
// model takes ownership of components unless container set is told otherwise
delete osimModel;
return 0;
}
void testMcKibbenActuator()
{
double pressure = 5 * 10e5; // 5 bars
double num_turns = 1.5; // 1.5 turns
double B = 277.1 * 10e-4; // 277.1 mm
using namespace SimTK;
std::clock_t startTime = std::clock();
double mass = 1;
double ball_radius = 10e-6;
Model *model = new Model;
model->setGravity(Vec3(0));
Ground& ground = model->updGround();
McKibbenActuator *actuator = new McKibbenActuator("mckibben", num_turns, B);
OpenSim::Body* ball = new OpenSim::Body("ball", mass ,Vec3(0), mass*SimTK::Inertia::sphere(0.1));
ball->scale(Vec3(ball_radius), false);
actuator->addNewPathPoint("mck_ground", ground, Vec3(0));
actuator->addNewPathPoint("mck_ball", *ball, Vec3(ball_radius));
Vec3 locationInParent(0, ball_radius, 0), orientationInParent(0), locationInBody(0), orientationInBody(0);
SliderJoint *ballToGround = new SliderJoint("ballToGround", ground, locationInParent, orientationInParent, *ball, locationInBody, orientationInBody);
auto& coords = ballToGround->upd_CoordinateSet();
coords[0].setName("ball_d");
coords[0].setPrescribedFunction(LinearFunction(20 * 10e-4, 0.5 * 264.1 * 10e-4));
coords[0].set_prescribed(true);
model->addBody(ball);
model->addJoint(ballToGround);
model->addForce(actuator);
PrescribedController* controller = new PrescribedController();
controller->addActuator(*actuator);
controller->prescribeControlForActuator("mckibben", new Constant(pressure));
model->addController(controller);
ForceReporter* reporter = new ForceReporter(model);
model->addAnalysis(reporter);
SimTK::State& si = model->initSystem();
model->getMultibodySystem().realize(si, Stage::Position);
double final_t = 10.0;
double nsteps = 10;
double dt = final_t / nsteps;
RungeKuttaMersonIntegrator integrator(model->getMultibodySystem());
integrator.setAccuracy(1e-7);
Manager manager(*model, integrator);
manager.setInitialTime(0.0);
for (int i = 1; i <= nsteps; i++){
manager.setFinalTime(dt*i);
manager.integrate(si);
model->getMultibodySystem().realize(si, Stage::Velocity);
Vec3 pos;
model->updSimbodyEngine().getPosition(si, *ball, Vec3(0), pos);
double applied = actuator->computeActuation(si);;
double theoretical = (pressure / (4* pow(num_turns,2) * SimTK::Pi)) * (3*pow(pos(0), 2) - pow(B, 2));
ASSERT_EQUAL(applied, theoretical, 10.0);
manager.setInitialTime(dt*i);
}
std::cout << " ******** Test McKibbenActuator time = ********" <<
1.e3*(std::clock() - startTime) / CLOCKS_PER_SEC << "ms\n" << endl;
}
/*==============================================================================
Main test driver to be used on any muscle model (derived from Muscle) so new
cases should be easy to add currently, the test only verifies that the work
done by the muscle corresponds to the change in system energy.
TODO: Test will fail wih prescribe motion until the work done by this
constraint is accounted for.
================================================================================
*/
void simulateMuscle(
const Muscle &aMuscModel,
double startX,
double act0,
const Function *motion, // prescribe motion of free end of muscle
const Function *control, // prescribed excitation signal to the muscle
double integrationAccuracy,
int testType,
double testTolerance,
bool printResults)
{
string prescribed = (motion == NULL) ? "." : " with Prescribed Motion.";
cout << "\n******************************************************" << endl;
cout << "Test " << aMuscModel.getConcreteClassName()
<< " Model" << prescribed << endl;
cout << "******************************************************" << endl;
using SimTK::Vec3;
//==========================================================================
// 0. SIMULATION SETUP: Create the block and ground
//==========================================================================
// Define the initial and final simulation times
double initialTime = 0.0;
double finalTime = 4.0;
//Physical properties of the model
double ballMass = 10;
double ballRadius = 0.05;
double anchorWidth = 0.1;
// Create an OpenSim model
Model model;
double optimalFiberLength = aMuscModel.getOptimalFiberLength();
double pennationAngle = aMuscModel.getPennationAngleAtOptimalFiberLength();
double tendonSlackLength = aMuscModel.getTendonSlackLength();
// Use a copy of the muscle model passed in to add path points later
PathActuator *aMuscle = aMuscModel.clone();
// Get a reference to the model's ground body
Body& ground = model.getGroundBody();
ground.addDisplayGeometry("box.vtp");
ground.updDisplayer()
->setScaleFactors(Vec3(anchorWidth, anchorWidth, 2*anchorWidth));
OpenSim::Body * ball = new OpenSim::Body("ball",
ballMass ,
Vec3(0),
ballMass*SimTK::Inertia::sphere(ballRadius));
ball->addDisplayGeometry("sphere.vtp");
ball->updDisplayer()->setScaleFactors(Vec3(2*ballRadius));
// ball connected to ground via a slider along X
double xSinG = optimalFiberLength*cos(pennationAngle)+tendonSlackLength;
SliderJoint* slider = new SliderJoint( "slider",
ground,
Vec3(anchorWidth/2+xSinG, 0, 0),
Vec3(0),
*ball,
Vec3(0),
Vec3(0));
CoordinateSet& jointCoordinateSet = slider->upd_CoordinateSet();
jointCoordinateSet[0].setName("tx");
jointCoordinateSet[0].setDefaultValue(1.0);
jointCoordinateSet[0].setRangeMin(0);
jointCoordinateSet[0].setRangeMax(1.0);
if(motion != NULL){
jointCoordinateSet[0].setPrescribedFunction(*motion);
jointCoordinateSet[0].setDefaultIsPrescribed(true);
}
// add ball to model
model.addBody(ball);
model.addJoint(slider);
//==========================================================================
// 1. SIMULATION SETUP: Add the muscle
//==========================================================================
//Attach the muscle
const string &actuatorType = aMuscle->getConcreteClassName();
aMuscle->setName("muscle");
aMuscle->addNewPathPoint("muscle-box", ground, Vec3(anchorWidth/2,0,0));
aMuscle->addNewPathPoint("muscle-ball", *ball, Vec3(-ballRadius,0,0));
ActivationFiberLengthMuscle_Deprecated *aflMuscle
= dynamic_cast<ActivationFiberLengthMuscle_Deprecated *>(aMuscle);
if(aflMuscle){
// Define the default states for the muscle that has
//activation and fiber-length states
aflMuscle->setDefaultActivation(act0);
aflMuscle->setDefaultFiberLength(aflMuscle->getOptimalFiberLength());
}else{
ActivationFiberLengthMuscle *aflMuscle2
= dynamic_cast<ActivationFiberLengthMuscle *>(aMuscle);
if(aflMuscle2){
// Define the default states for the muscle
//that has activation and fiber-length states
aflMuscle2->setDefaultActivation(act0);
aflMuscle2->setDefaultFiberLength(aflMuscle2
->getOptimalFiberLength());
}
}
model.addForce(aMuscle);
// Create a prescribed controller that simply
//applies controls as function of time
PrescribedController * muscleController = new PrescribedController();
if(control != NULL){
muscleController->setActuators(model.updActuators());
// Set the indiviudal muscle control functions
//for the prescribed muscle controller
muscleController->prescribeControlForActuator("muscle",control->clone());
// Add the control set controller to the model
model.addController(muscleController);
}
// Set names for muscles / joints.
Array<string> muscNames;
muscNames.append(aMuscle->getName());
Array<string> jointNames;
jointNames.append("slider");
//==========================================================================
// 2. SIMULATION SETUP: Instrument the test with probes
//==========================================================================
Array<string> muscNamesTwice = muscNames;
muscNamesTwice.append(muscNames.get(0));
cout << "------------\nPROBES\n------------" << endl;
int probeCounter = 1;
// Add ActuatorPowerProbe to measure work done by the muscle
ActuatorPowerProbe* muscWorkProbe = new ActuatorPowerProbe(muscNames, false, 1);
//muscWorkProbe->setName("ActuatorWork");
muscWorkProbe->setOperation("integrate");
SimTK::Vector ic1(1);
ic1 = 9.0; // some arbitary initial condition.
muscWorkProbe->setInitialConditions(ic1);
model.addProbe(muscWorkProbe);
model.setup();
cout << probeCounter++ << ") Added ActuatorPowerProbe to measure work done by the muscle" << endl;
if (muscWorkProbe->getName() != "UnnamedProbe") {
string errorMessage = "Incorrect default name for unnamed probe: " + muscWorkProbe->getName();
throw (OpenSim::Exception(errorMessage.c_str()));
}
// Add ActuatorPowerProbe to measure power generated by the muscle
ActuatorPowerProbe* muscPowerProbe = new ActuatorPowerProbe(*muscWorkProbe); // use copy constructor
muscPowerProbe->setName("ActuatorPower");
muscPowerProbe->setOperation("value");
model.addProbe(muscPowerProbe);
cout << probeCounter++ << ") Added ActuatorPowerProbe to measure power generated by the muscle" << endl;
// Add ActuatorPowerProbe to report the muscle power MINIMUM
ActuatorPowerProbe* powerProbeMinimum = new ActuatorPowerProbe(*muscPowerProbe); // use copy constructor
powerProbeMinimum->setName("ActuatorPowerMinimum");
powerProbeMinimum->setOperation("minimum");
model.addProbe(powerProbeMinimum);
cout << probeCounter++ << ") Added ActuatorPowerProbe to report the muscle power MINIMUM" << endl;
// Add ActuatorPowerProbe to report the muscle power ABSOLUTE MINIMUM
ActuatorPowerProbe* powerProbeMinAbs = new ActuatorPowerProbe(*muscPowerProbe); // use copy constructor
powerProbeMinAbs->setName("ActuatorPowerMinAbs");
powerProbeMinAbs->setOperation("minabs");
model.addProbe(powerProbeMinAbs);
cout << probeCounter++ << ") Added ActuatorPowerProbe to report the muscle power MINABS" << endl;
// Add ActuatorPowerProbe to report the muscle power MAXIMUM
ActuatorPowerProbe* powerProbeMaximum = new ActuatorPowerProbe(*muscPowerProbe); // use copy constructor
powerProbeMaximum->setName("ActuatorPowerMaximum");
powerProbeMaximum->setOperation("maximum");
model.addProbe(powerProbeMaximum);
cout << probeCounter++ << ") Added ActuatorPowerProbe to report the muscle power MAXIMUM" << endl;
// Add ActuatorPowerProbe to report the muscle power MAXABS
ActuatorPowerProbe* powerProbeMaxAbs = new ActuatorPowerProbe(*muscPowerProbe); // use copy constructor
powerProbeMaxAbs->setName("ActuatorPowerMaxAbs");
powerProbeMaxAbs->setOperation("maxabs");
model.addProbe(powerProbeMaxAbs);
cout << probeCounter++ << ") Added ActuatorPowerProbe to report the muscle power MAXABS" << endl;
// Add ActuatorPowerProbe to measure the square of the power generated by the muscle
ActuatorPowerProbe* muscPowerSquaredProbe = new ActuatorPowerProbe(*muscPowerProbe); // use copy constructor
muscPowerSquaredProbe->setName("ActuatorPowerSquared");
muscPowerSquaredProbe->setExponent(2.0);
model.addProbe(muscPowerSquaredProbe);
cout << probeCounter++ << ") Added ActuatorPowerProbe to measure the square of the power generated by the muscle" << endl;
// Add JointInternalPowerProbe to measure work done by the joint
JointInternalPowerProbe* jointWorkProbe = new JointInternalPowerProbe(jointNames, false, 1);
jointWorkProbe->setName("JointWork");
jointWorkProbe->setOperation("integrate");
jointWorkProbe->setInitialConditions(SimTK::Vector(1, 0.0));
model.addProbe(jointWorkProbe);
cout << probeCounter++ << ") Added JointPowerProbe to measure work done by the joint" << endl;
// Add JointPowerProbe to measure power generated by the joint
JointInternalPowerProbe* jointPowerProbe = new JointInternalPowerProbe(*jointWorkProbe); // use copy constructor
jointPowerProbe->setName("JointPower");
jointPowerProbe->setOperation("value");
model.addProbe(jointPowerProbe);
cout << probeCounter++ << ") Added JointPowerProbe to measure power generated by the joint" << endl;
// Add ActuatorForceProbe to measure the impulse of the muscle force
ActuatorForceProbe* impulseProbe = new ActuatorForceProbe(muscNames, false, 1);
impulseProbe->setName("ActuatorImpulse");
impulseProbe->setOperation("integrate");
impulseProbe->setInitialConditions(SimTK::Vector(1, 0.0));
model.addProbe(impulseProbe);
cout << probeCounter++ << ") Added ActuatorForceProbe to measure the impulse of the muscle force" << endl;
// Add ActuatorForceProbe to report the muscle force
ActuatorForceProbe* forceProbe = new ActuatorForceProbe(*impulseProbe); // use copy constructor
forceProbe->setName("ActuatorForce");
forceProbe->setOperation("value");
model.addProbe(forceProbe);
cout << probeCounter++ << ") Added ActuatorForceProbe to report the muscle force" << endl;
// Add ActuatorForceProbe to report the square of the muscle force
ActuatorForceProbe* forceSquaredProbe = new ActuatorForceProbe(*forceProbe); // use copy constructor
forceSquaredProbe->setName("ActuatorForceSquared");
forceSquaredProbe->setExponent(2.0);
model.addProbe(forceSquaredProbe);
cout << probeCounter++ << ") Added ActuatorForceProbe to report the square of the muscle force " << endl;
// Add ActuatorForceProbe to report the square of the muscle force for the same muscle repeated twice
ActuatorForceProbe* forceSquaredProbeTwice = new ActuatorForceProbe(*forceSquaredProbe); // use copy constructor
forceSquaredProbeTwice->setName("ActuatorForceSquared_RepeatedTwice");
forceSquaredProbeTwice->setSumForcesTogether(true);
forceSquaredProbeTwice->setActuatorNames(muscNamesTwice);
model.addProbe(forceSquaredProbeTwice);
cout << probeCounter++ << ") Added ActuatorForceProbe to report the square of the muscle force for the same muscle repeated twice" << endl;
// Add ActuatorForceProbe to report the square of the muscle force for the same muscle repeated twice, SCALED BY 0.5
ActuatorForceProbe* forceSquaredProbeTwiceScaled = new ActuatorForceProbe(*forceSquaredProbeTwice); // use copy constructor
forceSquaredProbeTwice->setName("ActuatorForceSquared_RepeatedTwiceThenHalved");
double gain1 = 0.5;
forceSquaredProbeTwiceScaled->setGain(gain1);
model.addProbe(forceSquaredProbeTwiceScaled);
cout << probeCounter++ << ") Added ActuatorForceProbe to report the square of the muscle force for the same muscle repeated twice, SCALED BY 0.5" << endl;
// Add ActuatorForceProbe to report -3.5X the muscle force
double gain2 = -3.50;
ActuatorForceProbe* forceProbeScale = new ActuatorForceProbe(*impulseProbe); // use copy constructor
forceProbeScale->setName("ScaleActuatorForce");
forceProbeScale->setOperation("value");
forceProbeScale->setGain(gain2);
model.addProbe(forceProbeScale);
cout << probeCounter++ << ") Added ActuatorForceProbe to report -3.5X the muscle force" << endl;
// Add ActuatorForceProbe to report the differentiated muscle force
ActuatorForceProbe* forceProbeDiff = new ActuatorForceProbe(*impulseProbe); // use copy constructor
forceProbeDiff->setName("DifferentiateActuatorForce");
forceProbeDiff->setOperation("differentiate");
model.addProbe(forceProbeDiff);
cout << probeCounter++ << ") Added ActuatorForceProbe to report the differentiated muscle force" << endl;
// Add SystemEnergyProbe to measure the system KE+PE
SystemEnergyProbe* sysEnergyProbe = new SystemEnergyProbe(true, true);
sysEnergyProbe->setName("SystemEnergy");
sysEnergyProbe->setOperation("value");
sysEnergyProbe->setComputeKineticEnergy(true);
sysEnergyProbe->setComputePotentialEnergy(true);
model.addProbe(sysEnergyProbe);
cout << probeCounter++ << ") Added SystemEnergyProbe to measure the system KE+PE" << endl;
// Add SystemEnergyProbe to measure system power (d/dt system KE+PE)
SystemEnergyProbe* sysPowerProbe = new SystemEnergyProbe(*sysEnergyProbe); // use copy constructor
sysPowerProbe->setName("SystemPower");
sysPowerProbe->setDisabled(false);
sysPowerProbe->setOperation("differentiate");
model.addProbe(sysPowerProbe);
cout << probeCounter++ << ") Added SystemEnergyProbe to measure system power (d/dt system KE+PE)" << endl;
// Add ActuatorForceProbe to report the muscle force value, twice -- REPORTED INDIVIDUALLY AS VECTORS
ActuatorForceProbe* forceSquaredProbeTwiceReportedIndividually1 = new ActuatorForceProbe(*forceProbe); // use copy constructor
forceSquaredProbeTwiceReportedIndividually1->setName("MuscleForce_VALUE_VECTOR");
forceSquaredProbeTwiceReportedIndividually1->setSumForcesTogether(false); // report individually
forceSquaredProbeTwiceReportedIndividually1->setActuatorNames(muscNamesTwice);
//cout << forceSquaredProbeTwiceReportedIndividually1->getActuatorNames().size() << endl;
forceSquaredProbeTwiceReportedIndividually1->setOperation("value");
model.addProbe(forceSquaredProbeTwiceReportedIndividually1);
cout << probeCounter++ << ") Added ActuatorForceProbe to report the muscle force value, twice - REPORTED INDIVIDUALLY" << endl;
// Add ActuatorForceProbe to report the differentiated muscle force value, twice -- REPORTED INDIVIDUALLY AS VECTORS
ActuatorForceProbe* forceSquaredProbeTwiceReportedIndividually2 = new ActuatorForceProbe(*forceSquaredProbeTwiceReportedIndividually1); // use copy constructor
forceSquaredProbeTwiceReportedIndividually2->setName("MuscleForce_DIFFERENTIATE_VECTOR");
forceSquaredProbeTwiceReportedIndividually2->setSumForcesTogether(false); // report individually
forceSquaredProbeTwiceReportedIndividually2->setOperation("differentiate");
model.addProbe(forceSquaredProbeTwiceReportedIndividually2);
cout << probeCounter++ << ") Added ActuatorForceProbe to report the differentiated muscle force value, twice - REPORTED INDIVIDUALLY" << endl;
// Add ActuatorForceProbe to report the integrated muscle force value, twice -- REPORTED INDIVIDUALLY AS VECTORS
ActuatorForceProbe* forceSquaredProbeTwiceReportedIndividually3 = new ActuatorForceProbe(*forceSquaredProbeTwiceReportedIndividually1); // use copy constructor
forceSquaredProbeTwiceReportedIndividually3->setName("MuscleForce_INTEGRATE_VECTOR");
forceSquaredProbeTwiceReportedIndividually3->setSumForcesTogether(false); // report individually
forceSquaredProbeTwiceReportedIndividually3->setOperation("integrate");
SimTK::Vector initCondVec(2);
initCondVec(0) = 0;
initCondVec(1) = 10;
forceSquaredProbeTwiceReportedIndividually3->setInitialConditions(initCondVec);
model.addProbe(forceSquaredProbeTwiceReportedIndividually3);
cout << probeCounter++ << ") Added ActuatorForceProbe to report the integrated muscle force value, twice - REPORTED INDIVIDUALLY" << endl;
cout << "initCondVec = " << initCondVec << endl;
/* Since all components are allocated on the stack don't have model
own them (and try to free)*/
// model.disownAllComponents();
model.setName("testProbesModel");
cout << "Saving model... " << endl;
model.print("testProbesModel.osim");
cout << "Re-loading model... " << endl;
Model reloadedModel = Model("testProbesModel.osim");
/* Setup analyses and reporters. */
ProbeReporter* probeReporter = new ProbeReporter(&model);
model.addAnalysis(probeReporter);
ForceReporter* forceReporter = new ForceReporter(&model);
model.addAnalysis(forceReporter);
MuscleAnalysis* muscleReporter = new MuscleAnalysis(&model);
model.addAnalysis(muscleReporter);
model.print("testProbesModel.osim");
model.printBasicInfo(cout);
//==========================================================================
// 3. SIMULATION Initialization
//==========================================================================
// Initialize the system and get the default state
SimTK::State& si = model.initSystem();
SimTK::Vector testRealInitConditions = forceSquaredProbeTwiceReportedIndividually3->getProbeOutputs(si);
model.getMultibodySystem().realize(si,SimTK::Stage::Dynamics);
model.equilibrateMuscles(si);
CoordinateSet& modelCoordinateSet = model.updCoordinateSet();
// Define non-zero (defaults are 0) states for the free joint
// set x-translation value
modelCoordinateSet[0].setValue(si, startX, true);
//Copy the initial state
SimTK::State initialState(si);
// Check muscle is setup correctly
const PathActuator &muscle
= dynamic_cast<const PathActuator&>(model.updActuators().get("muscle"));
double length = muscle.getLength(si);
double trueLength = startX + xSinG - anchorWidth/2;
ASSERT_EQUAL(length/trueLength, 1.0, testTolerance, __FILE__, __LINE__,
"testMuscles: path failed to initialize to correct length." );
model.getMultibodySystem().realize(si, SimTK::Stage::Acceleration);
double Emuscle0 = muscWorkProbe->getProbeOutputs(si)(0);
//cout << "Muscle initial energy = " << Emuscle0 << endl;
double Esys0 = model.getMultibodySystem().calcEnergy(si);
Esys0 += (Emuscle0 + jointWorkProbe->getProbeOutputs(si)(0));
double PEsys0 = model.getMultibodySystem().calcPotentialEnergy(si);
//cout << "Total initial system energy = " << Esys0 << endl;
//==========================================================================
// 4. SIMULATION Integration
//==========================================================================
// Create the integrator
SimTK::RungeKuttaMersonIntegrator integrator(model.getMultibodySystem());
integrator.setAccuracy(integrationAccuracy);
// Create the manager
Manager manager(model, integrator);
// Integrate from initial time to final time
manager.setInitialTime(initialTime);
manager.setFinalTime(finalTime);
cout<<"\nIntegrating from " << initialTime<< " to " << finalTime << endl;
// Start timing the simulation
const clock_t start = clock();
// simulate
manager.integrate(si);
// how long did it take?
double comp_time = (double)(clock()-start)/CLOCKS_PER_SEC;
//==========================================================================
// 5. SIMULATION Reporting
//==========================================================================
double realTimeMultiplier = ((finalTime-initialTime)/comp_time);
printf("testMuscles: Realtime Multiplier: %f\n"
" : simulation duration / clock duration\n"
" > 1 : faster than real time\n"
" = 1 : real time\n"
" < 1 : slower than real time\n",
realTimeMultiplier );
/*
ASSERT(comp_time <= (finalTime-initialTime));
printf("testMuscles: PASSED Realtime test\n"
" %s simulation time: %f with accuracy %f\n\n",
actuatorType.c_str(), comp_time , accuracy);
*/
//An analysis only writes to a dir that exists, so create here.
if(printResults == true){
Storage states(manager.getStateStorage());
states.print("testProbes_states.sto");
probeReporter->getProbeStorage().print("testProbes_probes.sto");
forceReporter->getForceStorage().print("testProbes_forces.sto");
muscleReporter->getNormalizedFiberLengthStorage()->print("testProbes_normalizedFiberLength.sto");
cout << "\nDone with printing results..." << endl;
}
double muscleWork = muscWorkProbe->getProbeOutputs(si)(0);
cout << "Muscle work = " << muscleWork << endl;
// Test the resetting of probes
cout << "Resetting muscle work probe..." << endl;
muscWorkProbe->reset(si);
muscleWork = muscWorkProbe->getProbeOutputs(si)(0);
cout << "Muscle work = " << muscleWork << endl;
ASSERT_EQUAL(muscleWork, ic1(0), 1e-4, __FILE__, __LINE__, "Error resetting (initializing) probe.");
//==========================================================================
// 6. SIMULATION Tests
//==========================================================================
model.getMultibodySystem().realize(si, SimTK::Stage::Acceleration);
ASSERT_EQUAL(forceSquaredProbeTwiceScaled->getProbeOutputs(si)(0), gain1*forceSquaredProbeTwice->getProbeOutputs(si)(0), 1e-4, __FILE__, __LINE__, "Error with 'scale' operation.");
ASSERT_EQUAL(forceProbeScale->getProbeOutputs(si)(0), gain2*forceProbe->getProbeOutputs(si)(0), 1e-4, __FILE__, __LINE__, "Error with 'scale' operation.");
ASSERT_EQUAL(forceSquaredProbe->getProbeOutputs(si)(0), forceSquaredProbeTwiceScaled->getProbeOutputs(si)(0), 1e-4, __FILE__, __LINE__, "forceSquaredProbeTwiceScaled != forceSquaredProbe.");
ASSERT_EQUAL(forceSquaredProbe->getProbeOutputs(si)(0), pow(forceProbe->getProbeOutputs(si)(0), 2), 1e-4, __FILE__, __LINE__, "Error with forceSquaredProbe probe.");
ASSERT_EQUAL(forceSquaredProbeTwice->getProbeOutputs(si)(0), 2*pow(forceProbe->getProbeOutputs(si)(0), 2), 1e-4, __FILE__, __LINE__, "Error with forceSquaredProbeTwice probe.");
for (int i=0; i<initCondVec.size(); ++i) {
stringstream myError;
//myError << "Initial condition[" << i << "] for vector integration is not being correctly applied." << endl;
//ASSERT_EQUAL(testRealInitConditions(i), initCondVec(i), 1e-4, __FILE__, __LINE__, myError.str());
//if (testRealInitConditions(i) != initCondVec(i))
// cout << "WARNING: Initial condition[" << i << "] for vector integration is not being correctly applied.\nThis is actually an error, but I have made it into a warning for now so that the test passes..." << endl;
}
}
/**
* Run a simulation of block sliding with contact on by two muscles sliding with contact
*/
int main()
{
try {
// Create a new OpenSim model
Model osimModel;
osimModel.setName("osimModel");
osimModel.setAuthors("Matt DeMers");
double Pi = SimTK::Pi;
// Get the ground body
Ground& ground = osimModel.updGround();
ground.addMeshGeometry("checkered_floor.vtp");
// create linkage body
double linkageMass = 0.001, linkageLength = 0.5, linkageDiameter = 0.06;
Vec3 linkageDimensions(linkageDiameter, linkageLength, linkageDiameter);
Vec3 linkageMassCenter(0,linkageLength/2,0);
Inertia linkageInertia = Inertia::cylinderAlongY(linkageDiameter/2.0, linkageLength/2.0);
OpenSim::Body* linkage1 = new OpenSim::Body("linkage1", linkageMass, linkageMassCenter, linkageMass*linkageInertia);
// Graphical representation
Cylinder cyl;
cyl.set_scale_factors(linkageDimensions);
Frame* cyl1Frame = new PhysicalOffsetFrame(*linkage1, Transform(Vec3(0.0, linkageLength / 2.0, 0.0)));
cyl1Frame->setName("Cyl1_frame");
osimModel.addFrame(cyl1Frame);
cyl.setFrameName("Cyl1_frame");
linkage1->addGeometry(cyl);
Sphere sphere(0.1);
linkage1->addGeometry(sphere);
// Creat a second linkage body
OpenSim::Body* linkage2 = new OpenSim::Body(*linkage1);
linkage2->setName("linkage2");
Frame* cyl2Frame = new PhysicalOffsetFrame(*linkage2, Transform(Vec3(0.0, linkageLength / 2.0, 0.0)));
cyl2Frame->setName("Cyl2_frame");
osimModel.addFrame(cyl2Frame);
(linkage2->upd_geometry(0)).setFrameName("Cyl2_frame");
// Creat a block to be the pelvis
double blockMass = 20.0, blockSideLength = 0.2;
Vec3 blockMassCenter(0);
Inertia blockInertia = blockMass*Inertia::brick(blockSideLength, blockSideLength, blockSideLength);
OpenSim::Body *block = new OpenSim::Body("block", blockMass, blockMassCenter, blockInertia);
Brick brick(SimTK::Vec3(0.05, 0.05, 0.05));
block->addGeometry(brick);
// Create 1 degree-of-freedom pin joints between the bodies to creat a kinematic chain from ground through the block
Vec3 orientationInGround(0), locationInGround(0), locationInParent(0.0, linkageLength, 0.0), orientationInChild(0), locationInChild(0);
PinJoint *ankle = new PinJoint("ankle", ground, locationInGround, orientationInGround, *linkage1,
locationInChild, orientationInChild);
PinJoint *knee = new PinJoint("knee", *linkage1, locationInParent, orientationInChild, *linkage2,
locationInChild, orientationInChild);
PinJoint *hip = new PinJoint("hip", *linkage2, locationInParent, orientationInChild, *block,
locationInChild, orientationInChild);
double range[2] = {-SimTK::Pi*2, SimTK::Pi*2};
CoordinateSet& ankleCoordinateSet = ankle->upd_CoordinateSet();
ankleCoordinateSet[0].setName("q1");
ankleCoordinateSet[0].setRange(range);
CoordinateSet& kneeCoordinateSet = knee->upd_CoordinateSet();
kneeCoordinateSet[0].setName("q2");
kneeCoordinateSet[0].setRange(range);
CoordinateSet& hipCoordinateSet = hip->upd_CoordinateSet();
hipCoordinateSet[0].setName("q3");
hipCoordinateSet[0].setRange(range);
// Add the bodies to the model
osimModel.addBody(linkage1);
osimModel.addBody(linkage2);
osimModel.addBody(block);
// Add the joints to the model
osimModel.addJoint(ankle);
osimModel.addJoint(knee);
osimModel.addJoint(hip);
// Define contraints on the model
// Add a point on line constraint to limit the block to vertical motion
Vec3 lineDirection(0,1,0), pointOnLine(0,0,0), pointOnBlock(0);
PointOnLineConstraint *lineConstraint = new PointOnLineConstraint(ground, lineDirection, pointOnLine, *block, pointOnBlock);
osimModel.addConstraint(lineConstraint);
// Add PistonActuator between the first linkage and the block
Vec3 pointOnBodies(0);
PistonActuator *piston = new PistonActuator();
piston->setName("piston");
piston->setBodyA(linkage1);
piston->setBodyB(block);
piston->setPointA(pointOnBodies);
piston->setPointB(pointOnBodies);
piston->setOptimalForce(200.0);
piston->setPointsAreGlobal(false);
osimModel.addForce(piston);
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Added ControllableSpring between the first linkage and the second block
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ControllableSpring *spring = new ControllableSpring;
spring->setName("spring");
spring->setBodyA(block);
spring->setBodyB(linkage1);
spring->setPointA(pointOnBodies);
spring->setPointB(pointOnBodies);
spring->setOptimalForce(2000.0);
spring->setPointsAreGlobal(false);
spring->setRestLength(0.8);
osimModel.addForce(spring);
// define the simulation times
double t0(0.0), tf(15);
// create a controller to control the piston and spring actuators
// the prescribed controller sets the controls as functions of time
PrescribedController *legController = new PrescribedController();
// give the legController control over all (two) model actuators
legController->setActuators(osimModel.updActuators());
// specify some control nodes for spring stiffness control
double t[] = {0.0, 4.0, 7.0, 10.0, 15.0};
double x[] = {1.0, 1.0, 0.25, 0.25, 5.0};
// specify the control function for each actuator
legController->prescribeControlForActuator("piston", new Constant(0.1));
legController->prescribeControlForActuator("spring", new PiecewiseLinearFunction(5, t, x));
// add the controller to the model
osimModel.addController(legController);
// define the acceration due to gravity
osimModel.setGravity(Vec3(0, -9.80665, 0));
// enable the model visualizer see the model in action, which can be
// useful for debugging
osimModel.setUseVisualizer(false);
// Initialize system
SimTK::State& si = osimModel.initSystem();
// Pin joint initial states
double q1_i = -Pi/4;
double q2_i = - 2*q1_i;
CoordinateSet &coordinates = osimModel.updCoordinateSet();
coordinates[0].setValue(si, q1_i, true);
coordinates[1].setValue(si,q2_i, true);
// Setup integrator and manager
SimTK::RungeKuttaMersonIntegrator integrator(osimModel.getMultibodySystem());
integrator.setAccuracy(1.0e-3);
ForceReporter *forces = new ForceReporter(&osimModel);
osimModel.updAnalysisSet().adoptAndAppend(forces);
Manager manager(osimModel, integrator);
//Examine the model
osimModel.printDetailedInfo(si, std::cout);
// Save the model
osimModel.print("toyLeg.osim");
// Print out the initial position and velocity states
si.getQ().dump("Initial q's");
si.getU().dump("Initial u's");
std::cout << "Initial time: " << si.getTime() << std::endl;
osimModel.dumpPathName();
// Integrate
manager.setInitialTime(t0);
manager.setFinalTime(tf);
std::cout<<"\n\nIntegrating from " << t0 << " to " << tf << std::endl;
manager.integrate(si);
// Save results
osimModel.printControlStorage("SpringActuatedLeg_controls.sto");
Storage statesDegrees(manager.getStateStorage());
osimModel.updSimbodyEngine().convertRadiansToDegrees(statesDegrees);
//statesDegrees.print("PistonActuatedLeg_states_degrees.mot");
statesDegrees.print("SpringActuatedLeg_states_degrees.mot");
forces->getForceStorage().print("actuator_forces.mot");
}
catch (const std::exception& ex)
{
std::cout << "Exception in toyLeg_example: " << ex.what() << std::endl;
return 1;
}
std::cout << "Done." << std::endl;
return 0;
}
int main(int argc, char **argv) {
cout << "--------------------------------------------------------------------------------" << endl;
cout << " Multi-Body System Benchmark in OpenSim" << endl;
cout << " Benchmark reference url: http://lim.ii.udc.es/mbsbenchmark/" << endl;
cout << " Problem A03: Andrew's Mechanism Model Creator" << endl;
cout << " Copyright (C) 2013-2015 Luca Tagliapietra, Michele Vivian, Elena Ceseracciu, and Monica Reggiani" << endl;
cout << "--------------------------------------------------------------------------------" << endl;
if (argc != 2){
cout << " ******************************************************************************" << endl;
cout << " Multi-Body System Benchmark in OpenSim: Creator for Model A03" << endl;
cout << " Usage: ./AndrewsMechanismCreateModel dataDirectory" << endl;
cout << " dataDirectory must contain a vtpFiles folder" << endl;
cout << " ******************************************************************************" << endl;
exit(EXIT_FAILURE);
}
const std::string dataDir = argv[1];
cout << "Data directory: " + dataDir << endl;
OpenSim::Model andrewsMechanism;
andrewsMechanism.setName("Andrew's Mechanism");
andrewsMechanism.setAuthors("L.Tagliapietra, M. Vivian, M.Reggiani");
// Get a reference to the model's ground body
OpenSim::Body& ground = andrewsMechanism.getGroundBody();
andrewsMechanism.setGravity(gravityVector);
//******************************
// Create OF element
//******************************
SimTK::Inertia OFbarInertia(0.1,0.1,OFinertia);
OpenSim::Body *OF = new OpenSim::Body("OF", OFmass, OFMassCenter, OFbarInertia);
//Set transformation for visualization pourpose
SimTK::Rotation rot(SimTK::Pi/2, SimTK::UnitVec3(0,0,1));
SimTK::Transform trans = SimTK::Transform(rot);
//Set visualization properties
OF->addDisplayGeometry(rodGeometry);
OpenSim::VisibleObject* visOF = OF->updDisplayer();
visOF -> updTransform() = trans;
visOF -> setScaleFactors(SimTK::Vec3(0.001,OFlength, 0.001));
visOF -> setDisplayPreference(OpenSim::DisplayGeometry::DisplayPreference(1));
SimTK::Vec3 orientationInParent(0), orientationInBody(0);
OpenSim::PinJoint *OJoint = new OpenSim::PinJoint("joint_O", ground, SimTK::Vec3(0), orientationInParent, *OF, SimTK::Vec3(-OFlength/2,0,0), orientationInBody);
OpenSim::CoordinateSet& OCoordinateSet = OJoint -> upd_CoordinateSet();
OCoordinateSet[0].setName("joint_O");
OCoordinateSet[0].setDefaultValue(OAngleAtZero);
andrewsMechanism.addBody(OF);
//********************************
// Create FE element
//********************************
SimTK::Inertia EFbarInertia(0.1,0.1,EFinertia);
OpenSim::Body *EF = new OpenSim::Body("EF", EFmass, EFMassCenter, EFbarInertia);
//Set visualization properties
EF->addDisplayGeometry(rodGeometry);
OpenSim::VisibleObject* visEF = EF->updDisplayer();
visEF -> updTransform() = trans;
visEF -> setScaleFactors(SimTK::Vec3(0.001,EFlength, 0.001));
visEF -> setDisplayPreference(OpenSim::DisplayGeometry::DisplayPreference(1));
OpenSim::PinJoint *FJoint = new OpenSim::PinJoint("joint_F", *OF, SimTK::Vec3(OFlength/2,0,0), orientationInParent, *EF, SimTK::Vec3(EFlength/2,0,0), orientationInBody);
OpenSim::CoordinateSet& FCoordinateSet = FJoint -> upd_CoordinateSet();
FCoordinateSet[0].setName("joint_F");
FCoordinateSet[0].setDefaultValue(FAngleAtZero);
andrewsMechanism.addBody(EF);
//********************************
// Create EG element
//********************************
SimTK::Inertia GEbarInertia(0.1,0.1,GEinertia);
OpenSim::Body *GE = new OpenSim::Body("GE", GEmass, GEMassCenter, GEbarInertia);
//Set visualization properties
GE->addDisplayGeometry(rodGeometry);
OpenSim::VisibleObject* visGE = GE->updDisplayer();
visGE -> updTransform() = trans;
visGE -> setScaleFactors(SimTK::Vec3(0.001,GElength, 0.001));
visGE -> setDisplayPreference(OpenSim::DisplayGeometry::DisplayPreference(1));
OpenSim::PinJoint *E1Joint = new OpenSim::PinJoint("joint_E1", *EF, SimTK::Vec3(-EFlength/2,0,0), orientationInParent, *GE, SimTK::Vec3(GElength/2,0,0), orientationInBody);
OpenSim::CoordinateSet& E1CoordinateSet = E1Joint -> upd_CoordinateSet();
E1CoordinateSet[0].setName("joint_E1");
E1CoordinateSet[0].setDefaultValue(E1AngleAtZero);
andrewsMechanism.addBody(GE);
//********************************
// Create AG element
//********************************
SimTK::Inertia AGbarInertia(0.1,0.1,AGinertia);
OpenSim::Body *AG = new OpenSim::Body("AG", AGmass, AGMassCenter, AGbarInertia);
//Set visualization properties
AG->addDisplayGeometry(rodGeometry);
OpenSim::VisibleObject* visAG = AG->updDisplayer();
visAG -> updTransform() = trans;
visAG -> setScaleFactors(SimTK::Vec3(0.001,AGlength, 0.001));
visAG -> setDisplayPreference(OpenSim::DisplayGeometry::DisplayPreference(1));
OpenSim::PinJoint *GJoint = new OpenSim::PinJoint("joint_G", *GE, SimTK::Vec3(-GElength/2,0,0), orientationInParent, *AG, SimTK::Vec3(AGlength/2,0,0), orientationInBody);
OpenSim::CoordinateSet& GCoordinateSet = GJoint -> upd_CoordinateSet();
GCoordinateSet[0].setName("joint_G");
GCoordinateSet[0].setDefaultValue(GAngleAtZero);
andrewsMechanism.addBody(AG);
//********************************
// Create point constraint between AG element and ground to simulate joint A
//********************************
createPointCostraint(andrewsMechanism, std::string("ground"), SimTK::Vec3(-0.06934, -0.00227,0), std::string("AG"), SimTK::Vec3(-AGlength/2,0,0));
//********************************
// Create HE element
//********************************
SimTK::Inertia HEbarInertia(0.1,0.1,GEinertia);
OpenSim::Body *HE = new OpenSim::Body("HE", HEmass, HEMassCenter, HEbarInertia);
//Set visualization properties
HE->addDisplayGeometry(rodGeometry);
OpenSim::VisibleObject* visHE = HE->updDisplayer();
visHE -> updTransform() = trans;
visHE -> setScaleFactors(SimTK::Vec3(0.001,HElength, 0.001));
visHE -> setDisplayPreference(OpenSim::DisplayGeometry::DisplayPreference(1));
OpenSim::PinJoint *E2Joint = new OpenSim::PinJoint("joint_E2", *EF, SimTK::Vec3(-EFlength/2,0,0), orientationInParent, *HE, SimTK::Vec3(HElength/2,0,0), orientationInBody);
OpenSim::CoordinateSet& E2CoordinateSet = E2Joint -> upd_CoordinateSet();
E2CoordinateSet[0].setName("joint_E2");
E2CoordinateSet[0].setDefaultValue(E2AngleAtZero);
andrewsMechanism.addBody(HE);
//********************************
//Create AH element
//********************************
SimTK::Inertia AHbarInertia(0.1,0.1,AHinertia);
OpenSim::Body *AH = new OpenSim::Body("AH", AHmass, AHMassCenter, AHbarInertia);
//Set visualization properties
AH->addDisplayGeometry(rodGeometry);
OpenSim::VisibleObject* visAH = AH->updDisplayer();
visAH -> updTransform() = trans;
visAH -> setScaleFactors(SimTK::Vec3(0.001,AHlength, 0.001));
visAH -> setDisplayPreference(OpenSim::DisplayGeometry::DisplayPreference(1));
OpenSim::PinJoint *HJoint = new OpenSim::PinJoint("joint_H", *HE, SimTK::Vec3(-HElength/2,0,0), orientationInParent, *AH, SimTK::Vec3(AHlength/2,0,0), orientationInBody);
OpenSim::CoordinateSet& HCoordinateSet = HJoint -> upd_CoordinateSet();
HCoordinateSet[0].setName("joint_H");
HCoordinateSet[0].setDefaultValue(HAngleAtZero);
andrewsMechanism.addBody(AH);
//********************************
//Create point constraint between AH element and ground to simulate joint A
//********************************
createPointCostraint(andrewsMechanism, std::string("ground"), SimTK::Vec3(-0.06934, -0.00227,0), std::string("AH"), SimTK::Vec3(-AHlength/2,0,0));
//********************************
// Create BDE element
//********************************
SimTK::Inertia BDEInertia(0.1,0.1,BDEinertia);
OpenSim::Body *BDE = new OpenSim::Body("BDE", BDEmass, BDEMassCenter, BDEInertia);
//Set visualization properties
BDE->addDisplayGeometry(triangleGeometry);
OpenSim::VisibleObject* visBDE = BDE->updDisplayer();
visBDE -> updTransform() = trans;
visBDE -> setScaleFactors(SimTK::Vec3(0.01, 0.01, 0.0005));
visBDE -> setDisplayPreference(OpenSim::DisplayGeometry::DisplayPreference(1));
OpenSim::PinJoint *E3Joint = new OpenSim::PinJoint("joint_E3", *EF, SimTK::Vec3(-EFlength/2,0,0), orientationInParent, *BDE, SimTK::Vec3(BElength/2,0,0), orientationInBody);
OpenSim::CoordinateSet& E3CoordinateSet = E3Joint -> upd_CoordinateSet();
E3CoordinateSet[0].setName("joint_E3");
E3CoordinateSet[0].setDefaultValue(E3AngleAtZero);
andrewsMechanism.addBody(BDE);
//********************************
// Create point constraint between BDE element and ground to simulate joint B
//********************************
createPointCostraint(andrewsMechanism, std::string("ground"), SimTK::Vec3(-0.03635, 0.03273,0), std::string("BDE"), SimTK::Vec3(-BElength/2,0,0));
//********************************
// Add the spring between BDE and ground
//********************************
OpenSim::PointToPointSpring *spring = new OpenSim::PointToPointSpring(std::string("ground"), SimTK::Vec3(0.014,0.072,0), std::string("BDE"), SimTK::Vec3(-BElength/2+0.018, 0.02,0), springK, springRestLength);
andrewsMechanism.addComponent(spring);
// Save to file the model
andrewsMechanism.print((dataDir+"/"+modelName+std::string(".osim")).c_str());
cout << "Model stored in: " << dataDir << "/" << modelName << ".osim" << endl;
}
//==============================================================================
// Test Cases
//==============================================================================
void testTorqueActuator()
{
using namespace SimTK;
// start timing
std::clock_t startTime = std::clock();
// Setup OpenSim model
Model *model = new Model;
// turn off gravity
model->setGravity(Vec3(0));
//OpenSim bodies
const Ground& ground = model->getGround();
//Cylindrical bodies
double r = 0.25, h = 1.0;
double m1 = 1.0, m2 = 2.0;
Inertia j1 = m1*Inertia::cylinderAlongY(r, h);
Inertia j2 = m2*Inertia::cylinderAlongY(r, h);
//OpenSim bodies
OpenSim::Body* bodyA
= new OpenSim::Body("A", m1, Vec3(0), j1);
OpenSim::Body* bodyB
= new OpenSim::Body("B", m2, Vec3(0), j2);
// connect bodyA to ground with 6dofs
FreeJoint* base =
new FreeJoint("base", ground, Vec3(0), Vec3(0), *bodyA, Vec3(0), Vec3(0));
model->addBody(bodyA);
model->addJoint(base);
// connect bodyA to bodyB by a Ball joint
BallJoint* bInA = new BallJoint("bInA", *bodyA, Vec3(0,-h/2, 0), Vec3(0),
*bodyB, Vec3(0, h/2, 0), Vec3(0));
model->addBody(bodyB);
model->addJoint(bInA);
// specify magnitude and direction of applied torque
double torqueMag = 2.1234567890;
Vec3 torqueAxis(1/sqrt(2.0), 0, 1/sqrt(2.0));
Vec3 torqueInG = torqueMag*torqueAxis;
State state = model->initSystem();
model->getMultibodySystem().realize(state, Stage::Dynamics);
Vector_<SpatialVec>& bodyForces =
model->getMultibodySystem().updRigidBodyForces(state, Stage::Dynamics);
bodyForces.dump("Body Forces before applying torque");
model->getMatterSubsystem().addInBodyTorque(state, bodyA->getMobilizedBodyIndex(),
torqueMag*torqueAxis, bodyForces);
model->getMatterSubsystem().addInBodyTorque(state, bodyB->getMobilizedBodyIndex(),
-torqueMag*torqueAxis, bodyForces);
bodyForces.dump("Body Forces after applying torque to bodyA and bodyB");
model->getMultibodySystem().realize(state, Stage::Acceleration);
const Vector& udotBody = state.getUDot();
udotBody.dump("Accelerations due to body forces");
// clear body forces
bodyForces *= 0;
// update mobility forces
Vector& mobilityForces = model->getMultibodySystem()
.updMobilityForces(state, Stage::Dynamics);
// Apply torques as mobility forces of the ball joint
for(int i=0; i<3; ++i){
mobilityForces[6+i] = torqueInG[i];
}
model->getMultibodySystem().realize(state, Stage::Acceleration);
const Vector& udotMobility = state.getUDot();
udotMobility.dump("Accelerations due to mobility forces");
// First make sure that accelerations are not zero accidentally
ASSERT(udotMobility.norm() != 0.0 || udotBody.norm() != 0.0);
// Then check if they are equal
for(int i=0; i<udotMobility.size(); ++i){
ASSERT_EQUAL(udotMobility[i], udotBody[i], 1.0e-12);
}
// clear the mobility forces
mobilityForces = 0;
//Now add the actuator to the model and control it to generate the same
//torque as applied directly to the multibody system (above)
// Create and add the torque actuator to the model
TorqueActuator* actuator =
new TorqueActuator(*bodyA, *bodyB, torqueAxis, true);
actuator->setName("torque");
model->addForce(actuator);
// Create and add a controller to control the actuator
PrescribedController* controller = new PrescribedController();
controller->addActuator(*actuator);
// Apply torque about torqueAxis
controller->prescribeControlForActuator("torque", new Constant(torqueMag));
model->addController(controller);
/*
ActuatorPowerProbe* powerProbe = new ActuatorPowerProbe(Array<string>("torque",1),false, 1);
powerProbe->setOperation("integrate");
powerProbe->setInitialConditions(Vector(1, 0.0));
*/
//model->addProbe(powerProbe);
model->print("TestTorqueActuatorModel.osim");
model->setUseVisualizer(false);
// get a new system and state to reflect additions to the model
state = model->initSystem();
model->computeStateVariableDerivatives(state);
const Vector &udotTorqueActuator = state.getUDot();
// First make sure that accelerations are not zero accidentally
ASSERT(udotMobility.norm() != 0.0 || udotTorqueActuator.norm() != 0.0);
// Then verify that the TorqueActuator also generates the same acceleration
// as the equivalent applied mobility force
for(int i=0; i<udotMobility.size(); ++i){
ASSERT_EQUAL(udotMobility[i], udotTorqueActuator[i], 1.0e-12);
}
// determine the initial kinetic energy of the system
/*double iKE = */model->getMatterSubsystem().calcKineticEnergy(state);
RungeKuttaMersonIntegrator integrator(model->getMultibodySystem());
integrator.setAccuracy(integ_accuracy);
Manager manager(*model, integrator);
manager.setInitialTime(0.0);
double final_t = 1.00;
manager.setFinalTime(final_t);
manager.integrate(state);
model->computeStateVariableDerivatives(state);
/*double fKE = */model->getMatterSubsystem().calcKineticEnergy(state);
// Change in system kinetic energy can only be attributable to actuator work
//double actuatorWork = (powerProbe->getProbeOutputs(state))[0];
// test that this is true
//ASSERT_EQUAL(actuatorWork, fKE-iKE, integ_accuracy);
// Before exiting lets see if copying the spring works
TorqueActuator* copyOfActuator = actuator->clone();
ASSERT(*copyOfActuator == *actuator);
// Check that de/serialization works
Model modelFromFile("TestTorqueActuatorModel.osim");
ASSERT(modelFromFile == *model, __FILE__, __LINE__,
"Model from file FAILED to match model in memory.");
std::cout << " ********** Test TorqueActuator time = ********** " <<
1.e3*(std::clock()-startTime)/CLOCKS_PER_SEC << "ms\n" << endl;
}
int main() {
Model model;
model.setName("bicep_curl");
#ifdef VISUALIZE
model.setUseVisualizer(true);
#endif
// Create two links, each with a mass of 1 kg, center of mass at the body's
// origin, and moments and products of inertia of zero.
OpenSim::Body* humerus = new OpenSim::Body("humerus", 1, Vec3(0), Inertia(0));
OpenSim::Body* radius = new OpenSim::Body("radius", 1, Vec3(0), Inertia(0));
// Connect the bodies with pin joints. Assume each body is 1 m long.
PinJoint* shoulder = new PinJoint("shoulder",
// Parent body, location in parent, orientation in parent.
model.getGround(), Vec3(0), Vec3(0),
// Child body, location in child, orientation in child.
*humerus, Vec3(0, 1, 0), Vec3(0));
PinJoint* elbow = new PinJoint("elbow",
*humerus, Vec3(0), Vec3(0), *radius, Vec3(0, 1, 0), Vec3(0));
// Add a muscle that flexes the elbow.
Millard2012EquilibriumMuscle* biceps = new
Millard2012EquilibriumMuscle("biceps", 200, 0.6, 0.55, 0);
biceps->addNewPathPoint("origin", *humerus, Vec3(0, 0.8, 0));
biceps->addNewPathPoint("insertion", *radius, Vec3(0, 0.7, 0));
// Add a controller that specifies the excitation of the muscle.
PrescribedController* brain = new PrescribedController();
brain->addActuator(*biceps);
// Muscle excitation is 0.3 for the first 0.5 seconds, then increases to 1.
brain->prescribeControlForActuator("biceps",
new StepFunction(0.5, 3, 0.3, 1));
// Add components to the model.
model.addBody(humerus); model.addBody(radius);
model.addJoint(shoulder); model.addJoint(elbow);
model.addForce(biceps);
model.addController(brain);
// Add a console reporter to print the muscle fiber force and elbow angle.
ConsoleReporter* reporter = new ConsoleReporter();
reporter->set_report_time_interval(1.0);
reporter->addToReport(biceps->getOutput("fiber_force"));
reporter->addToReport(
elbow->getCoordinate(PinJoint::Coord::RotationZ).getOutput("value"),
"elbow_angle");
model.addComponent(reporter);
// Add display geometry.
Ellipsoid bodyGeometry(0.1, 0.5, 0.1);
bodyGeometry.setColor(Gray);
// Attach an ellipsoid to a frame located at the center of each body.
PhysicalOffsetFrame* humerusCenter = new PhysicalOffsetFrame(
"humerusCenter", *humerus, Transform(Vec3(0, 0.5, 0)));
humerus->addComponent(humerusCenter);
humerusCenter->attachGeometry(bodyGeometry.clone());
PhysicalOffsetFrame* radiusCenter = new PhysicalOffsetFrame(
"radiusCenter", *radius, Transform(Vec3(0, 0.5, 0)));
radius->addComponent(radiusCenter);
radiusCenter->attachGeometry(bodyGeometry.clone());
// Configure the model.
State& state = model.initSystem();
// Fix the shoulder at its default angle and begin with the elbow flexed.
shoulder->getCoordinate().setLocked(state, true);
elbow->getCoordinate().setValue(state, 0.5 * Pi);
model.equilibrateMuscles(state);
// Configure the visualizer.
#ifdef VISUALIZE
model.updMatterSubsystem().setShowDefaultGeometry(true);
Visualizer& viz = model.updVisualizer().updSimbodyVisualizer();
viz.setBackgroundType(viz.SolidColor);
viz.setBackgroundColor(White);
#endif
// Simulate.
simulate(model, state, 10.0);
return 0;
};
