This is a simple example of using a marker tracking goal.
#include <OpenSim/Simulation/SimbodyEngine/PinJoint.h>
#include <OpenSim/Simulation/MarkersReference.h>
#include <OpenSim/Actuators/CoordinateActuator.h>
#include <Moco/osimMoco.h>
std::unique_ptr<Model> createDoublePendulumModel() {
auto model = make_unique<Model>();
model->setName("double_pendulum");
using SimTK::Vec3;
using SimTK::Inertia;
auto* b0 = new OpenSim::Body("b0", 1, Vec3(0), Inertia(1));
model->addBody(b0);
auto* b1 = new OpenSim::Body("b1", 1, Vec3(0), Inertia(1));
model->addBody(b1);
auto* m0 = new Marker("m0", *b0, Vec3(0));
auto* m1 = new Marker("m1", *b1, Vec3(0));
model->addMarker(m0);
model->addMarker(m1);
auto* j0 = new PinJoint("j0", model->getGround(), Vec3(0), Vec3(0),
*b0, Vec3(-1, 0, 0), Vec3(0));
auto& q0 = j0->updCoordinate();
q0.setRangeMin(-10);
q0.setRangeMax(10);
q0.setName("q0");
auto* j1 = new PinJoint("j1",
*b0, Vec3(0), Vec3(0), *b1, Vec3(-1, 0, 0), Vec3(0));
auto& q1 = j1->updCoordinate();
q1.setRangeMin(-10);
q1.setRangeMax(10);
q1.setName("q1");
model->addJoint(j0);
model->addJoint(j1);
auto* tau0 = new CoordinateActuator();
tau0->setCoordinate(&j0->updCoordinate());
tau0->setName("tau0");
tau0->setOptimalForce(1);
tau0->setMinControl(-40);
tau0->setMaxControl(40);
model->addComponent(tau0);
auto* tau1 = new CoordinateActuator();
tau1->setCoordinate(&j1->updCoordinate());
tau1->setName("tau1");
tau1->setOptimalForce(1);
tau1->setMinControl(-40);
tau1->setMaxControl(40);
model->addComponent(tau1);
Ellipsoid bodyGeometry(0.5, 0.1, 0.1);
SimTK::Transform transform(SimTK::Vec3(-0.5, 0, 0));
auto* b0Center = new PhysicalOffsetFrame("b0_center", *b0, transform);
b0->addComponent(b0Center);
b0Center->attachGeometry(bodyGeometry.clone());
auto* b1Center = new PhysicalOffsetFrame("b1_center", *b1, transform);
b1->addComponent(b1Center);
b1Center->attachGeometry(bodyGeometry.clone());
model->finalizeConnections();
return model;
}
int main() {
study.setName("double_pendulum_marker_tracking");
problem.
setModel(createDoublePendulumModel());
double finalTime = 1.0;
TimeSeriesTableVec3 markerTrajectories;
markerTrajectories.setColumnLabels({"/markerset/m0", "/markerset/m1"});
for (double time = 0; time < finalTime; time += 0.01) {
SimTK::Real q0 = (time / 1.0) * 0.5 * SimTK::Pi;
SimTK::Real q1 = (time / 1.0) * 0.25 * SimTK::Pi;
SimTK::Vec3 m0(cos(q0), sin(q0), 0);
SimTK::Vec3 m1 = m0 + SimTK::Vec3(cos(q0 + q1), sin(q0 + q1), 0);
markerTrajectories.appendRow(time, {m0, m1});
}
Set<MarkerWeight> markerWeights;
markerWeights.cloneAndAppend({"/markerset/m0", 100});
markerWeights.cloneAndAppend({"/markerset/m1", 10});
MarkersReference ref(markerTrajectories, markerWeights);
solver.set_num_mesh_intervals(50);
solver.set_verbosity(2);
solver.set_optim_hessian_approximation("exact");
solution.
write(
"exampleMarkerTracking_solution.sto");
return EXIT_SUCCESS;
}