/**
* Compute the initial states for a simulation.
*
* The caller should send in an initial guess. The Qs and Us are set
* based on the desired trajectories. The actuator states are set by
* solving for a desired set of actuator forces, and then letting the states
* come to equilibrium for those forces.
*
* @param rTI Initial time in normalized time. Note this is changed to
* the time corresponding to the new initial states on return.
* @param s Initial states.
*/
void CMC::
computeInitialStates(SimTK::State& s, double &rTI)
{
int i,j;
int N = _predictor->getNX();
SimTK::State initialState = s;
Array<double> xmin(0.01,N),forces(0.0,N);
double tiReal = rTI;
if( _verbose ) {
cout<<"\n\n=============================================\n";
cout<<"enter CMC.computeInitialStates: ti="<< rTI << " q's=" << s.getQ() <<endl;
cout<<"\nenter CMC.computeInitialStates: ti="<< rTI << " u's=" << s.getU() <<endl;
cout<<"\nenter CMC.computeInitialStates: ti="<< rTI << " z's=" << s.getZ() <<endl;
cout<<"=============================================\n";
}
// TURN ANALYSES OFF
_model->updAnalysisSet().setOn(false);
// CONSTRUCT CONTROL SET
ControlSet xiSet;
for(i=0;i< getNumControls();i++) {
ControlConstant *x = new ControlConstant();
x->setName(_controlSet.get(i).getName());
x->setIsModelControl(true);
// This is not a very good way to set the bounds on the controls because ConrtolConstant only supports constant
// min/max bounds but we may have time-dependent min/max curves specified in the controls constraints file
//
Control& xPredictor = _controlSet.get(i);
x->setDefaultParameterMin(xPredictor.getDefaultParameterMin());
x->setDefaultParameterMax(xPredictor.getDefaultParameterMax());
double xmin = xPredictor.getControlValueMin(tiReal);
if(!SimTK::isNaN(xmin)) x->setControlValueMin(tiReal,xmin);
double xmax = xPredictor.getControlValueMax(tiReal);
if(!SimTK::isNaN(xmax)) x->setControlValueMax(tiReal,xmax);
xiSet.adoptAndAppend(x);
}
// ACTUATOR EQUILIBRIUM
// 1
//
// perform integration but reset the coords and speeds so only actuator
// states at changed
obtainActuatorEquilibrium(s,tiReal,0.200,xmin,true);
if( _verbose ) {
cout<<"\n\n=============================================\n";
cout<<"#1 act Equ. CMC.computeInitialStates: ti="<< rTI << " q's=" << s.getQ() <<endl;
cout<<"\n#1 act Equ. CMC.computeInitialStates: ti="<< rTI << " u's=" << s.getU() <<endl;
cout<<"\n#1 act Equ. CMC.computeInitialStates: ti="<< rTI << " z's=" << s.getZ() <<endl;
cout<<"=============================================\n";
}
restoreConfiguration( s, initialState ); // set internal coord,speeds to initial vals.
// 2
obtainActuatorEquilibrium(s,tiReal,0.200,xmin,true);
if( _verbose ) {
cout<<"\n\n=============================================\n";
cout<<"#2 act Equ. CMC.computeInitialStates: ti="<< rTI << " q's=" << s.getQ() <<endl;
cout<<"\n#2 act Equ. CMC.computeInitialStates: ti="<< rTI << " u's=" << s.getU() <<endl;
cout<<"\n#2 act Equ. CMC.computeInitialStates: ti="<< rTI << " z's=" << s.getZ() <<endl;
cout<<"=============================================\n";
}
restoreConfiguration( s, initialState );
// CHANGE THE TARGET DT ON THE CONTROLLER TEMPORARILY
double oldTargetDT = getTargetDT();
double newTargetDT = 0.030;
setTargetDT(newTargetDT);
// REPEATEDLY CONTROL OVER THE FIRST TIME STEP
Array<double> xi(0.0, getNumControls());
for(i=0;i<2;i++) {
// CLEAR ANY PREVIOUS CONTROL NODES
for(j=0;j<_controlSet.getSize();j++) {
ControlLinear& control = (ControlLinear&)_controlSet.get(j);
control.clearControlNodes();
}
// COMPUTE CONTROLS
s.updTime() = rTI;
computeControls( s, xiSet);
_model->updAnalysisSet().setOn(false);
// GET CONTROLS
xiSet.getControlValues(rTI,xi);
// OBTAIN EQUILIBRIUM
if(i<1) {
obtainActuatorEquilibrium(s,tiReal,0.200,xi,true);
restoreConfiguration(s, initialState );
}
}
// GET NEW STATES
_predictor->evaluate(s, &xi[0], &forces[0]);
rTI += newTargetDT;
// CLEANUP
setTargetDT(oldTargetDT);
_model->updAnalysisSet().setOn(true);
if( _verbose ) {
cout<<"\n\n=============================================\n";
cout<<"finish CMC.computeInitialStates: ti="<< rTI << " q's=" << s.getQ() <<endl;
cout<<"\nfinish CMC.computeInitialStates: ti="<< rTI << " u's=" << s.getU() <<endl;
cout<<"\nfinish CMC.computeInitialStates: ti="<< rTI << " z's=" << s.getZ() <<endl;
cout<<"=============================================\n";
}
}
//==========================================================================================================
void testControlSetControllerOnBlock()
{
using namespace SimTK;
// Create a new OpenSim model
Model osimModel;
osimModel.setName("osimModel");
// Get the ground body
OpenSim::Body& ground = osimModel.getGroundBody();
// Create a 20 kg, 0.1 m^3 block body
double blockMass = 20.0, blockSideLength = 0.1;
Vec3 blockMassCenter(0), groundOrigin(0), blockInGround(0, blockSideLength/2, 0);
Inertia blockIntertia = Inertia::brick(blockSideLength, blockSideLength, blockSideLength);
OpenSim::Body block("block", blockMass, blockMassCenter, blockMass*blockIntertia);
//Create a free joint with 6 degrees-of-freedom
SimTK::Vec3 noRotation(0);
SliderJoint blockToGround("",ground, blockInGround, noRotation, block, blockMassCenter, noRotation);
// Create 6 coordinates (degrees-of-freedom) between the ground and block
CoordinateSet& jointCoordinateSet = blockToGround.upd_CoordinateSet();
double posRange[2] = {-1, 1};
jointCoordinateSet[0].setName("xTranslation");
jointCoordinateSet[0].setMotionType(Coordinate::Translational);
jointCoordinateSet[0].setRange(posRange);
// Add the block body to the model
osimModel.addBody(&block);
// Define a single coordinate actuator.
CoordinateActuator actuator(jointCoordinateSet[0].getName());
actuator.setName("actuator");
// Add the actuator to the model
osimModel.addForce(&actuator);
double initialTime = 0;
double finalTime = 1.0;
// Define the initial and final control values
double controlForce[1] = {100};
// Create two control signals
ControlLinear control;
control.setName("actuator");
// Create a control set and add the controls to the set
ControlSet actuatorControls;
actuatorControls.adoptAndAppend(&control);
actuatorControls.setMemoryOwner(false);
actuatorControls.setControlValues(initialTime, controlForce);
actuatorControls.setControlValues(finalTime, controlForce);
// Create a control set controller that simply applies controls from a ControlSet
ControlSetController actuatorController;
// Make a copy and set it on the ControlSetController as it takes ownership of the
// ControlSet passed in
actuatorController.setControlSet((ControlSet*)Object::SafeCopy(&actuatorControls));
// add the controller to the model
osimModel.addController(&actuatorController);
// Initialize the system and get the state representing the state system
SimTK::State& si = osimModel.initSystem();
// Specify zero slider joint kinematic states
CoordinateSet &coordinates = osimModel.updCoordinateSet();
coordinates[0].setValue(si, 0.0); // x translation
coordinates[0].setSpeedValue(si, 0.0); // x speed
// Create the integrator and manager for the simulation.
double accuracy = 1.0e-3;
SimTK::RungeKuttaMersonIntegrator integrator(osimModel.getMultibodySystem());
integrator.setAccuracy(accuracy);
Manager manager(osimModel, integrator);
// Integrate from initial time to final time
manager.setInitialTime(initialTime);
manager.setFinalTime(finalTime);
std::cout<<"\n\nIntegrating from "<<initialTime<<" to "<<finalTime<<std::endl;
manager.integrate(si);
si.getQ().dump("Final position:");
double x_err = fabs(coordinates[0].getValue(si) - 0.5*(controlForce[0]/blockMass)*finalTime*finalTime);
ASSERT(x_err <= accuracy, __FILE__, __LINE__, "ControlSetControllerOnBlock failed to produce the expected motion.");
// Save the simulation results
Storage states(manager.getStateStorage());
states.print("block_push.sto");
osimModel.disownAllComponents();
}// end of testControlSetControllerOnBlock()