RigidBodyPlanningWithODESolverAndControls.cpp

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/* Author: Ryan Luna */
 
#include <ompl/control/SpaceInformation.h>
#include <ompl/base/spaces/SE2StateSpace.h>
#include <ompl/control/ODESolver.h>
#include <ompl/control/spaces/RealVectorControlSpace.h>
#include <ompl/control/SimpleSetup.h>
#include <ompl/config.h>
#include <iostream>
#include <valarray>
#include <limits>
 
namespace ob = ompl::base;
namespace oc = ompl::control;
 
// Kinematic car model object definition.  This class does NOT use ODESolver to propagate the system.
class KinematicCarModel : public oc::StatePropagator
{
public:
    KinematicCarModel(const oc::SpaceInformationPtr &si) : oc::StatePropagator(si)
    {
        space_ = si->getStateSpace();
        carLength_ = 0.2;
        timeStep_ = 0.01;
    }
 
    void propagate(const ob::State *state, const oc::Control *control, const double duration,
                   ob::State *result) const override
    {
        EulerIntegration(state, control, duration, result);
    }
 
protected:
    // Explicit Euler Method for numerical integration.
    void EulerIntegration(const ob::State *start, const oc::Control *control, const double duration,
                          ob::State *result) const
    {
        double t = timeStep_;
        std::valarray<double> dstate;
        space_->copyState(result, start);
        while (t < duration + std::numeric_limits<double>::epsilon())
        {
            ode(result, control, dstate);
            update(result, timeStep_ * dstate);
            t += timeStep_;
        }
        if (t + std::numeric_limits<double>::epsilon() > duration)
        {
            ode(result, control, dstate);
            update(result, (t - duration) * dstate);
        }
    }

    void ode(const ob::State *state, const oc::Control *control, std::valarray<double> &dstate) const
    {
        const double *u = control->as<oc::RealVectorControlSpace::ControlType>()->values;
        const double theta = state->as<ob::SE2StateSpace::StateType>()->getYaw();
 
        dstate.resize(3);
        dstate[0] = u[0] * cos(theta);
        dstate[1] = u[0] * sin(theta);
        dstate[2] = u[0] * tan(u[1]) / carLength_;
    }

    void update(ob::State *state, const std::valarray<double> &dstate) const
    {
        ob::SE2StateSpace::StateType &s = *state->as<ob::SE2StateSpace::StateType>();
        s.setX(s.getX() + dstate[0]);
        s.setY(s.getY() + dstate[1]);
        s.setYaw(s.getYaw() + dstate[2]);
        space_->enforceBounds(state);
    }
 
    ob::StateSpacePtr space_;
    double carLength_;
    double timeStep_;
};
 
// Definition of the ODE for the kinematic car.
// This method is analogous to the above KinematicCarModel::ode function.
void KinematicCarODE(const oc::ODESolver::StateType &q, const oc::Control *control, oc::ODESolver::StateType &qdot)
{
    const double *u = control->as<oc::RealVectorControlSpace::ControlType>()->values;
    const double theta = q[2];
    double carLength = 0.2;
 
    // Zero out qdot
    qdot.resize(q.size(), 0);
 
    qdot[0] = u[0] * cos(theta);
    qdot[1] = u[0] * sin(theta);
    qdot[2] = u[0] * tan(u[1]) / carLength;
}
 
// This is a callback method invoked after numerical integration.
void KinematicCarPostIntegration(const ob::State * /*state*/, const oc::Control * /*control*/,
                                 const double /*duration*/, ob::State *result)
{
    // Normalize orientation between 0 and 2*pi
    ob::SO2StateSpace SO2;
    SO2.enforceBounds(result->as<ob::SE2StateSpace::StateType>()->as<ob::SO2StateSpace::StateType>(1));
}
 
bool isStateValid(const oc::SpaceInformation *si, const ob::State *state)
{
    //    ob::ScopedState<ob::SE2StateSpace>
    const auto *se2state = state->as<ob::SE2StateSpace::StateType>();

    const auto *pos = se2state->as<ob::RealVectorStateSpace::StateType>(0);

    const auto *rot = se2state->as<ob::SO2StateSpace::StateType>(1);

 
    // return a value that is always true but uses the two variables we define, so we avoid compiler warnings
    return si->satisfiesBounds(state) && (const void *)rot != (const void *)pos;
}

class DemoControlSpace : public oc::RealVectorControlSpace
{
public:
    DemoControlSpace(const ob::StateSpacePtr &stateSpace) : oc::RealVectorControlSpace(stateSpace, 2)
    {
    }
};
 
void planWithSimpleSetup()
{
    auto space(std::make_shared<ob::SE2StateSpace>());

    ob::RealVectorBounds bounds(2);
    bounds.setLow(-1);
    bounds.setHigh(1);
 
    space->setBounds(bounds);
 
    // create a control space
    auto cspace(std::make_shared<DemoControlSpace>(space));
 
    // set the bounds for the control space
    ob::RealVectorBounds cbounds(2);
    cbounds.setLow(-0.3);
    cbounds.setHigh(0.3);
 
    cspace->setBounds(cbounds);
 
    // define a simple setup class
    oc::SimpleSetup ss(cspace);
 
    // set state validity checking for this space
    oc::SpaceInformation *si = ss.getSpaceInformation().get();
    ss.setStateValidityChecker([si](const ob::State *state) { return isStateValid(si, state); });
 
    // Setting the propagation routine for this space:
    // KinematicCarModel does NOT use ODESolver
    // ss.setStatePropagator(std::make_shared<KinematicCarModel>(ss.getSpaceInformation()));
 
    // Use the ODESolver to propagate the system.  Call KinematicCarPostIntegration
    // when integration has finished to normalize the orientation values.
    auto odeSolver(std::make_shared<oc::ODEBasicSolver<>>(ss.getSpaceInformation(), &KinematicCarODE));
    ss.setStatePropagator(oc::ODESolver::getStatePropagator(odeSolver, &KinematicCarPostIntegration));

    ob::ScopedState<ob::SE2StateSpace> start(space);
    start->setX(-0.5);
    start->setY(0.0);
    start->setYaw(0.0);

    ob::ScopedState<ob::SE2StateSpace> goal(space);
    goal->setX(0.0);
    goal->setY(0.5);
    goal->setYaw(0.0);

    ss.setStartAndGoalStates(start, goal, 0.05);

    ss.setup();

    ob::PlannerStatus solved = ss.solve(10.0);
 
    if (solved)
    {
        std::cout << "Found solution:" << std::endl;
 
        ss.getSolutionPath().asGeometric().printAsMatrix(std::cout);
    }
    else
        std::cout << "No solution found" << std::endl;
}
 
int main(int /*argc*/, char ** /*argv*/)
{
    std::cout << "OMPL version: " << OMPL_VERSION << std::endl;
 
    planWithSimpleSetup();
 
    return 0;
}