void perturb_initial_conditions()
{
const double LV_PERTURB = 0.1;
const double AV_PERTURB = 0.05;
const double ELLIPSE_RADIUS_PERTURB = 0.1;
VectorNd gc, gv;
Point3d dummy1, dummy2;
// perturb the initial position
ellipse->get_generalized_coordinates_euler(gc);
gc[0] += normal_gen();
gc[1] += normal_gen();
// perturb the initial rotation
Quatd quat = Matrix3d::rot_Z(randu() * M_PI * 2.0);
gc[3] = quat.x;
gc[4] = quat.y;
gc[5] = quat.z;
gc[6] = quat.w;
// perturb the ellipse radius
std::ostringstream x_rad, y_rad;
// x_rad << (randu() * ELLIPSE_RADIUS_PERTURB * 2.0 - ELLIPSE_RADIUS_PERTURB);
// y_rad << (randu() * ELLIPSE_RADIUS_PERTURB * 2.0 - ELLIPSE_RADIUS_PERTURB);
x_rad << "1.0";
y_rad << "2.0";
setenv("ELLIPSE_X_RAD", x_rad.str().c_str(), 1);
setenv("ELLIPSE_Y_RAD", y_rad.str().c_str(), 1);
// ensure that the initial configuration is not in contact with the ground
VectorNd newgc = gc;
ellipse->set_generalized_coordinates_euler(newgc);
// get the collision detector
shared_ptr<CollisionDetection> coldet = sim->get_collision_detection();
// get the collision geometries for the ellipse and the ground
shared_ptr<CollisionGeometry> ground_cg = ground->geometries.front();
shared_ptr<CollisionGeometry> ellipse_cg = ellipse->geometries.front();
// check for contact between ground and ellipse
if (coldet->calc_signed_dist(ground_cg, ellipse_cg, dummy1, dummy2) <= 0.0)
{
// reset the generalized coords
ellipse->set_generalized_coordinates_euler(gc);
// try again
perturb_initial_conditions();
return;
}
// perturb the initial velocity
ellipse->get_generalized_velocity(DynamicBodyd::eSpatial, gv);
for (unsigned i=0; i< 3; i++)
gv[i+3] += normal_gen()*LV_PERTURB;
gv[5] += normal_gen()*AV_PERTURB;
ellipse->set_generalized_velocity(DynamicBodyd::eSpatial, gv);
}
// setup simulator callback
void post_step_callback(Simulator* sim)
{
// output the sliding velocity at the contact
std::ofstream out("ke.dat", std::ostream::app);
out << sim->current_time << " " << box->calc_kinetic_energy() << std::endl;
out.close();
}
// setup simulator callback
void post_step_callback(Simulator* s)
{
const unsigned X = 0, Y = 1, Z = 2;
// setup the sphere radius
const double R = 1.0;
// get the bottom of the sphere
Transform3d wTs = Pose3d::calc_relative_pose(sphere->get_pose(), GLOBAL);
shared_ptr<Pose3d> Pbot(new Pose3d);
Pbot->rpose = GLOBAL;
Pbot->x = wTs.x;
Pbot->x[Z] -= R;
// get the velocity of the sphere at the contact point
SVelocityd v = sphere->get_velocity();
Transform3d botTv = Pose3d::calc_relative_pose(v.pose, Pbot);
SVelocityd xd = botTv.transform(v);
Vector3d linear = xd.get_linear();
/*
SVelocityd v = sphere->get_velocity();
Origin3d xd(v.get_linear());
Origin3d omega(v.get_angular());
Origin3d s(1.0, 0.0, 0.0);
Origin3d t(0.0, 1.0, 0.0);
Origin3d crosss = Origin3d::cross(-wTs.x, s);
Origin3d crosst = Origin3d::cross(-wTs.x, t);
*/
// output the sliding velocity at the contact
std::ofstream out("contactv.dat", std::ostream::app);
out << sim->current_time << " " << linear[X] << " " << linear[Y] << " " << linear[Z] << std::endl;
// out << sim->current_time << " " << (s.dot(xd) + crosss.dot(omega)) << " " << (t.dot(xd) + crosst.dot(omega)) << std::endl;
// out << sim->current_time << " " << v[3] << " " << v[4] << " " << v[5] << " " << v[0] << " " << v[1] << " " << v[2] << std::endl;
out.close();
out.open("velocity.dat", std::ostream::app);
out << sim->current_time << " " << v[3] << " " << v[4] << " " << v[5] << " " << v[0] << " " << v[1] << " " << v[2] << std::endl;
out.close();
out.open("ke.dat", std::ostream::app);
out << sim->current_time << " " << sphere->calc_kinetic_energy() << std::endl;
out.close();
}
// simulator callback
void post_step_callback(Simulator* sim)
{
// output the sliding velocity at the contact
std::ofstream out("rke.dat", std::ostream::app);
out << sim->current_time << " " << box->calc_kinetic_energy() << std::endl;
out.close();
// save the generalized coordinates of the box
out.open("telemetry.box", std::ostream::app);
VectorNd q;
box->get_generalized_coordinates_euler(q);
out << sim->current_time;
for (unsigned i=0; i< q.size(); i++)
out << " " << q[i];
out << std::endl;
out.close();
}
// setup simulator mini-callback
void post_ministep_callback(ConstraintSimulator* sim)
{
const unsigned Y = 1;
// see whether there is significant undesired rotation
AAngled aa = Pose3d::calc_relative_pose(wheel->get_pose(), GLOBAL).q;
if ((std::fabs(aa.x) > 1e-4 || std::fabs(aa.z) > 1e-4) && std::fabs(aa.angle) > 1e-6)
{
std::cerr << "excessive angular rotation out of the plane: " << std::max(std::fabs(aa.x), std::fabs(aa.z)) << std::endl;
}
// output the velocity
std::ofstream out("velocity.dat", std::ostream::app);
out << sim->current_time << " " << wheel->get_velocity().get_angular()[Y] << std::endl;
out.close();
}
void init(void* separator, const std::map<std::string, Moby::BasePtr>& read_map, double time)
{
// wipe out existing files
std::ofstream out("rke.dat");
out.close();
out.open("telemetry.box");
out.close();
out.open("manifold.change");
out.close();
// get a reference to the TimeSteppingSimulator instance
for (std::map<std::string, Moby::BasePtr>::const_iterator i = read_map.begin();
i !=read_map.end(); i++)
{
// Find the simulator reference
if (!sim)
sim = boost::dynamic_pointer_cast<TimeSteppingSimulator>(i->second);
if (i->first == "box")
box = boost::dynamic_pointer_cast<RigidBody>(i->second);
if (!grav)
grav = boost::dynamic_pointer_cast<GravityForce>(i->second);
}
sim->post_step_callback_fn = &post_step_callback;
sim->constraint_callback_fn = &post_contact_callback;
srand(0);
// set the position, orientation, and velocities to some random values
Pose3d x = *box->get_pose();
rand_pose(x);
// add 2.0 to the initial pose for the box
x.x[1] += 2.0;
box->set_pose(x);
// set random velocity for the box
shared_ptr<const Pose3d> P = box->get_velocity().pose;
box->set_velocity(rand_velocity(P));
}
// setup simulator callback
void post_step_callback(Simulator* sim)
{
const unsigned X = 0, Y = 1, Z = 2;
// setup the box height
const double H = 1.0;
// get the bottoms of the box
Transform3d wTs = Pose3d::calc_relative_pose(box->get_pose(), GLOBAL);
Vector3d p1 = wTs.transform_point(Vector3d(-.5, -.5, -.5, box->get_pose()));
Vector3d p2 = wTs.transform_point(Vector3d(-.5, -.5, .5, box->get_pose()));
Vector3d p3 = wTs.transform_point(Vector3d(.5, -.5, -.5, box->get_pose()));
Vector3d p4 = wTs.transform_point(Vector3d(.5, -.5, .5, box->get_pose()));
// get the bottoms of the box in the global frame
shared_ptr<Pose3d> P1(new Pose3d), P2(new Pose3d), P3(new Pose3d), P4(new Pose3d);
P1->x = Origin3d(p1);
P2->x = Origin3d(p2);
P3->x = Origin3d(p3);
P4->x = Origin3d(p4);
// get the velocity of the box at the contact points
SVelocityd v = box->get_velocity();
Vector3d xd1 = Pose3d::calc_relative_pose(v.pose, P1).transform(v).get_linear();
Vector3d xd2 = Pose3d::calc_relative_pose(v.pose, P2).transform(v).get_linear();
Vector3d xd3 = Pose3d::calc_relative_pose(v.pose, P3).transform(v).get_linear();
Vector3d xd4 = Pose3d::calc_relative_pose(v.pose, P4).transform(v).get_linear();
/*
SVelocityd v = box->get_velocity();
Origin3d xd(v.get_linear());
Origin3d omega(v.get_angular());
Origin3d s(1.0, 0.0, 0.0);
Origin3d t(0.0, 1.0, 0.0);
Origin3d crosss = Origin3d::cross(-wTs.x, s);
Origin3d crosst = Origin3d::cross(-wTs.x, t);
*/
// output the sliding velocity at the contact
std::ofstream out("contactv.dat", std::ostream::app);
out << sim->current_time << " " << xd1[X] << " " << xd1[Y] << " " << xd2[X] << " " << xd2[Y] << " " << xd3[X] << " " << xd3[Y] << " " << xd4[X] << " " << xd4[Y] << std::endl;
// out << sim->current_time << " " << (s.dot(xd) + crosss.dot(omega)) << " " << (t.dot(xd) + crosst.dot(omega)) << std::endl;
// out << sim->current_time << " " << v[3] << " " << v[4] << " " << v[5] << " " << v[0] << " " << v[1] << " " << v[2] << std::endl;
out.close();
out.open("ke.dat", std::ostream::app);
out << sim->current_time << " " << box->calc_kinetic_energy() << std::endl;
out.close();
}
// setup simulator callback
void post_step_callback(Simulator* sim)
{
const unsigned Z = 2;
std::ofstream out("energy.dat", std::ostream::app);
double KE = wheel->calc_kinetic_energy();
Transform3d gTw = Pose3d::calc_relative_pose(wheel->get_pose(), GLOBAL);
double PE = wheel->get_inertia().m*gTw.x[Z]*-grav->gravity[Z];
out << sim->current_time << " " << KE << " " << PE << " " << (KE+PE) << std::endl;
out.close();
// see whether there is significant undesired rotation
AAngled aa = Pose3d::calc_relative_pose(wheel->get_pose(), GLOBAL).q;
out.open("angular.dat", std::ostream::app);
out << sim->current_time << " " << std::fabs(aa.x) << " " << std::fabs(aa.z) << " " << " " << std::fabs(aa.angle) << std::endl;
out.close();
// see whether we are in a ballistic flight phase
TimeSteppingSimulator* esim = (TimeSteppingSimulator*) sim;
boost::shared_ptr<CollisionDetection> coldet = esim->get_collision_detection();
CollisionGeometryPtr cgw = wheel->geometries.front();
CollisionGeometryPtr cgg = ground->geometries.front();
Point3d cpw, cpg;
double dist = coldet->calc_signed_dist(cgw, cgg, cpw, cpg);
if (dist > 1e-4)
std::cerr << "-- in a ballistic flight phase at time " << sim->current_time << std::endl;
// fast exit conditions
if (FIND_MAP)
{
if (KE < NEAR_ZERO)
{
std::cerr << "kinetic energy too small!" << std::endl;
out.open("system.state", std::ostream::app);
out << "0.0" << std::endl;
exit(0);
}
if (sim->current_time > 100.0)
{
std::cerr << "simulation ran too long!" << std::endl;
out.open("system.state", std::ostream::app);
out << "DnF" << std::endl;
exit(0);
}
}
// if we're finding the return map, see whether the next step has been
// encountered
if (FIND_MAP)
{
// look to see whether the last processed contact was a new spoke
std::ifstream in("IPC.token");
if (in.fail())
return;
in.close();
// it was, output the state of the system
std::ofstream out("system.state", std::ostream::app);
out << " " << wheel->get_velocity().get_angular()[1] << std::endl;
out.close();
exit(0);
}
}
void init(void* separator, const std::map<std::string, Moby::BasePtr>& read_map, double time)
{
const unsigned Z = 2;
// overwrite the energy and velocity files
std::ofstream out("energy.dat");
out.close();
out.open("velocity.dat");
out.close();
out.open("cvio.dat");
out.close();
// If use robot is active also init dynamixel controllers
// get a reference to the TimeSteppingSimulator instance
for (std::map<std::string, Moby::BasePtr>::const_iterator i = read_map.begin();
i !=read_map.end(); i++)
{
// Find the simulator reference
if (!sim)
sim = boost::dynamic_pointer_cast<TimeSteppingSimulator>(i->second);
if (i->first == "WHEEL")
wheel = boost::dynamic_pointer_cast<RigidBody>(i->second);
if (i->first == "GROUND")
ground = boost::dynamic_pointer_cast<RigidBody>(i->second);
if (!grav)
grav = boost::dynamic_pointer_cast<GravityForce>(i->second);
}
sim->post_step_callback_fn = &post_step_callback;
sim->post_mini_step_callback_fn = &post_ministep_callback;
// initialize the system to the fixed point
// double theta = M_PI/N_SPOKES;
double theta = 0.0;
const double ALPHA = 0.2;
const double LAMBDA_SQ = 2.0/3;
const double MU = 1.0 + LAMBDA_SQ * (std::cos(2*M_PI/N_SPOKES) - 1.0);
assert(MU > 0.0 && MU < 1.0);
// double theta_dot = std::sqrt((4.0*MU*MU*LAMBDA_SQ*std::sin(M_PI/N_SPOKES)*std::sin(ALPHA))/(1.0 - MU*MU));
// get theta dot
char* theta_dot_str = getenv("RIMLESS_WHEEL_THETAD");
if (!theta_dot_str)
{
std::cerr << "RIMLESS_WHEEL_THETAD not defined!" << std::endl;
exit(-1);
}
double theta_dot = std::atof(theta_dot_str);
out.open("system.state", std::ostream::app);
out << theta_dot << " ";
out.close();
// get the distance per revolution
const double DIST_PER_REV = 2*M_PI*R;
const double REV_PER_SEC = theta_dot / (M_PI*2.0);
const double DIST_PER_SEC = DIST_PER_REV * REV_PER_SEC;
// set the rotation about y
Quatd q_wheel = Matrix3d::rot_Y(theta);
Vector3d lvel(DIST_PER_SEC, 0.0, 0.0, wheel->get_velocity().pose);
Vector3d avel(0, theta_dot, 0, wheel->get_velocity().pose);
Pose3d P;
P.x.set_zero();
P.x[Z] = 0.866025403784439;
P.q = q_wheel;
wheel->set_pose(P);
SVelocityd v;
v.set_angular(avel);
v.set_linear(lvel);
wheel->set_velocity(v);
/*
// Set initial conditions from ruina paper
Ravelin::VectorNd x,xd;
part->get_generalized_coordinates( Moby::DynamicBody::eEuler,x);
part->get_generalized_velocity( Moby::DynamicBody::eSpatial,xd);
x[1] = 0; // x
x[2] = 0; // y
x[3] = 0.1236; // z
// 9.866765986740000e-002
// -9.248610676160000e-003
// -1.601658349552200e-001
// 3.435833890385830e+000
// -1.322096551035500e-001
// -1.990961987794000e-002
// 4.712423746697700e-001
// -3.925591686648300e-001
double PHI = 9.866765986740000e-002, // yaw
THE = -1.601658349552200e-001, // pitch + alpha
PSI = -9.248610676160000e-003; // roll
Ravelin::Matrix3d Rz = Ravelin::Matrix3d::rot_Z(PHI),
Ry = Ravelin::Matrix3d::rot_Y(THE),
Rx = Ravelin::Matrix3d::rot_X(PSI),
Rzxy = Ry.mult(Rx).mult(Rz);
Quatd q = Quatd(Rzxy);
x[4] = q[0];
x[5] = q[1];
x[6] = q[2];
x[7] = q[3];
x[0] = 3.435833890385830e+000 + THETA_SW_OFFSET; // Theta_sw
// Convert Time derivative of RPY to angular velocity (w)
double dPHI = -1.322096551035500e-001, // d yaw / dt
dTHE = 4.712423746697700e-001, // d pitch / dt
dPSI = -1.990961987794000e-002; // d roll / dt
// a_dot is time derivative of RPY
// Numerically derive skew symmetric
// angular velocity tensor matrix W
double h = 1e-6;
Matrix3d
Rz2 = Ravelin::Matrix3d::rot_Z(PHI + h*dPHI),
Rx2 = Ravelin::Matrix3d::rot_X(PSI + h*dPSI),
Ry2 = Ravelin::Matrix3d::rot_Y(THE + h*dTHE);
Matrix3d
Rzxy2 = Ry2.mult(Rx2).mult(Rz2);
Matrix3d
W = ((Rzxy2-Rzxy)/h).mult_transpose(Rzxy);
// w is angular velocity
Vector3d w((W(2,1)-W(1,2))/2,(W(0,2)-W(2,0))/2,(W(1,0)-W(0,1))/2);
xd.set_zero();
xd.set_sub_vec(4,w);
xd[0] = -3.925591686648300e-001; // Theta_sw
part->set_generalized_coordinates( Moby::DynamicBody::eEuler,x);
part->set_generalized_velocity( Moby::DynamicBody::eSpatial,xd);
*/
}
