PinballPlanning.cpp

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/* Author: Beverly Xu */
 
#include "ompl/control/planners/rrt/HyRRT.h"
#include "ompl/base/StateSpace.h"
#include "ompl/control/spaces/RealVectorControlSpace.h"
#include "ompl/base/spaces/HybridStateSpace.h"
#include "ompl/control/ODESolver.h"
 
struct PinballSetup
{
    double paddleLength = 1;
    double paddleWidth = 0.25;
    std::vector<std::vector<double>> paddleCoords = {{1, -1}, {2.5, -4}, {1.5, -5}, {3, -7}, {1, -8}};
};

double distanceFunc(ompl::base::State *state1, ompl::base::State *state2)
{
    double dist = 0;
    dist = hypot(state1->as<ompl::base::HybridStateSpace::StateType>()
                         ->as<ompl::base::RealVectorStateSpace::StateType>(0)
                         ->values[0] -
                     state2->as<ompl::base::HybridStateSpace::StateType>()
                         ->as<ompl::base::RealVectorStateSpace::StateType>(0)
                         ->values[0],
                 state1->as<ompl::base::HybridStateSpace::StateType>()
                         ->as<ompl::base::RealVectorStateSpace::StateType>(0)
                         ->values[1] -
                     state2->as<ompl::base::HybridStateSpace::StateType>()
                         ->as<ompl::base::RealVectorStateSpace::StateType>(0)
                         ->values[1]);
    return fabs(dist);
}

bool inPaddle(ompl::control::HyRRT::Motion *motion, std::vector<double> paddleCoord)
{
    PinballSetup pinballSetup;
 
    auto *motion_state =
        motion->state->as<ompl::base::CompoundState>()->as<ompl::base::RealVectorStateSpace::StateType>(0);
    double paddleX = paddleCoord[0];
    double paddleY = paddleCoord[1];
    double x1 = motion_state->values[0];
    double x2 = motion_state->values[1];
    double v1 = motion_state->values[2];
    double v2 = motion_state->values[3];
 
    bool inPaddle = false;
 
    if ((x1 >= paddleX && x1 <= paddleX + pinballSetup.paddleLength) &&
        (x2 >= paddleY && x2 <= paddleY + pinballSetup.paddleWidth / 2) && v2 < 0)
        inPaddle = true;  // In jump set if both velocity and position vectors are directed toward top of paddle
    else if ((x1 >= paddleX && x1 <= paddleX + pinballSetup.paddleLength) &&
             (x2 >= paddleY + pinballSetup.paddleWidth / 2 && x2 <= paddleY + pinballSetup.paddleWidth) && v2 > 0)
        inPaddle = true;  // In jump set if both velocity and position vectors are directed toward bottom of paddle
    else if ((x1 >= paddleX && x1 <= paddleX + pinballSetup.paddleLength / 4) &&
             (x2 >= paddleY && x2 <= paddleY + pinballSetup.paddleWidth) && v1 > 0)
        inPaddle = true;  // In jump set if both velocity and position vectors are directed toward left side of paddle
    else if ((x1 >= paddleX + (3 / 4) * pinballSetup.paddleLength && x1 <= paddleX + pinballSetup.paddleLength) &&
             (x2 >= paddleY && x2 <= paddleY + pinballSetup.paddleWidth) && v1 < 0)
        inPaddle = true;  // In jump set if both velocity and position vectors are directed toward left side of paddle
 
    return inPaddle;
}

bool jumpSet(ompl::control::HyRRT::Motion *motion)
{
    PinballSetup pinballSetup;
 
    auto *motion_state =
        motion->state->as<ompl::base::CompoundState>()->as<ompl::base::RealVectorStateSpace::StateType>(0);
    double x1 = motion_state->values[0];
    double v1 = motion_state->values[2];
 
    for (std::vector<double> paddleCoord : pinballSetup.paddleCoords)  // If ball is in any of the paddles
    {
        if (inPaddle(motion, paddleCoord))
            return true;
    }
 
    if ((x1 <= 0 && v1 < 0) || (x1 >= 5 && v1 > 0))  // If ball is in either side wall
        return true;
 
    return false;
}

bool flowSet(ompl::control::HyRRT::Motion *motion)
{
    return !jumpSet(motion);
}

bool unsafeSet(ompl::control::HyRRT::Motion *motion)
{
    auto *motion_state =
        motion->state->as<ompl::base::CompoundState>()->as<ompl::base::RealVectorStateSpace::StateType>(0);
    double x1 = motion_state->values[0];
    double x2 = motion_state->values[1];
 
    if (((x1 >= 0 && x1 < 1) || (x1 > 4 && x1 <= 5)) && x2 <= -10)
        return true;
    return false;
}

void flowODE(const ompl::control::ODESolver::StateType &x_cur, const ompl::control::Control *u,
             ompl::control::ODESolver::StateType &x_new)
{
    (void)u;  // No control is applied when a state is in the flow set
 
    // Retrieve the current orientation of the pinball.
    const double v_1 = x_cur[2];
    const double v_2 = x_cur[3];
    const double a_1 = x_cur[4];
    const double a_2 = x_cur[5];
 
    // Ensure qdot is the same size as q.  Zero out all values.
    x_new.resize(x_cur.size(), 0);
 
    x_new[0] = v_1;
    x_new[1] = v_2;
    x_new[2] = a_1;
    x_new[3] = a_2;
    x_new[4] = 0;  // No change to acceleration
    x_new[5] = 0;  // No change to acceleration
}

ompl::base::State *discreteSimulator(ompl::base::State *x_cur, const ompl::control::Control *u,
                                     ompl::base::State *new_state)
{
    // Retrieve control values.
    const double *control = u->as<ompl::control::RealVectorControlSpace::ControlType>()->values;
    const double u_x = control[0];
 
    auto *state_values = x_cur->as<ompl::base::HybridStateSpace::StateType>()
                             ->as<ompl::base::RealVectorStateSpace::StateType>(0)
                             ->values;
    double x1 = state_values[0];
    double x2 = state_values[1];
    double v1 = state_values[2];
    double v2 = state_values[3];
    double a1 = state_values[4];
    double a2 = state_values[5];
 
    if ((x1 <= 0 && v1 < 0) || (x1 >= 5 && v1 > 0))  // If state is colliding with the wall
    {
        new_state->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[2] = -v1 * 0.8;
        new_state->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[3] = v2;
    }
    else if (v2 < 0)  // If state is colliding with the top of the paddle
    {
        new_state->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[2] = v1 + u_x;
        new_state->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[3] = -v2 * 0.6;
    }
    else if (v2 > 0)  // If state is colliding with the bottom of the paddle
    {
        new_state->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[2] = v1;
        new_state->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[3] = -v2 * 0.6;
    }
    else  // If state is colliding with the side of the paddle
    {
        new_state->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[2] = -(v1 * 0.6 + std::copysign(u_x, v1));  // Input is in the same direction as rebound
        new_state->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[3] = v2;
    }
 
    // The position and acceleration doesn't change
    new_state->as<ompl::base::HybridStateSpace::StateType>()
        ->as<ompl::base::RealVectorStateSpace::StateType>(0)
        ->values[0] = x1;
    new_state->as<ompl::base::HybridStateSpace::StateType>()
        ->as<ompl::base::RealVectorStateSpace::StateType>(0)
        ->values[1] = x2;
    new_state->as<ompl::base::HybridStateSpace::StateType>()
        ->as<ompl::base::RealVectorStateSpace::StateType>(0)
        ->values[4] = a1;
    new_state->as<ompl::base::HybridStateSpace::StateType>()
        ->as<ompl::base::RealVectorStateSpace::StateType>(0)
        ->values[5] = a2;
    return new_state;
}
 
// Define goal region [1, 4] x (-inf, -10] x ℝ⁴
class EuclideanGoalRegion : public ompl::base::Goal
{
public:
    EuclideanGoalRegion(const ompl::base::SpaceInformationPtr &si) : ompl::base::Goal(si)
    {
    }
 
    virtual bool isSatisfied(const ompl::base::State *st, double *distance) const
    {
        // perform any operations and return a truth value
        std::vector<double> goalRegion = {1, 4, -10};  // x-min, x-max, y
        auto *values = st->as<ompl::base::CompoundState>()->as<ompl::base::RealVectorStateSpace::StateType>(0)->values;
 
        if (values[0] > goalRegion[1])
            *distance = hypot(values[1] + 10, values[0] - goalRegion[1]);
        else if (values[0] < goalRegion[0])
            *distance = hypot(values[1] + 10, values[0] - goalRegion[0]);
        else
            *distance = values[1] + 10;
 
        return values[0] >= goalRegion[0] && values[0] <= goalRegion[1] && values[1] <= goalRegion[2];
    }
 
    virtual bool isSatisfied(const ompl::base::State *st) const
    {
        double distance = -1.0;
        return isSatisfied(st, &distance);
    }
};
 
int main()
{
    // Set the bounds of space
    ompl::base::RealVectorStateSpace *statespace = new ompl::base::RealVectorStateSpace(0);
    statespace->addDimension(0, 5);
    statespace->addDimension(-10, 0);
    statespace->addDimension(-10, 10);
    statespace->addDimension(-10, 10);
    statespace->addDimension(-10, 10);
    statespace->addDimension(-10, 10);
    ompl::base::StateSpacePtr stateSpacePtr(statespace);
 
    ompl::base::HybridStateSpace *hybridSpace = new ompl::base::HybridStateSpace(stateSpacePtr);
    ompl::base::StateSpacePtr hybridSpacePtr(hybridSpace);
 
    // Define control space
    ompl::control::RealVectorControlSpace *flowControlSpace =
        new ompl::control::RealVectorControlSpace(hybridSpacePtr, 1);
    ompl::control::RealVectorControlSpace *jumpControlSpace =
        new ompl::control::RealVectorControlSpace(hybridSpacePtr, 1);
 
    ompl::base::RealVectorBounds flowBounds(1);
    flowBounds.setLow(0, 0);
    flowBounds.setHigh(0, 0);
    flowControlSpace->setBounds(flowBounds);
 
    ompl::base::RealVectorBounds jumpBounds(1);
    jumpBounds.setLow(0, -4);
    jumpBounds.setHigh(0, 4);
    jumpControlSpace->setBounds(jumpBounds);
 
    ompl::control::RealVectorControlUniformSampler flowControlSampler(flowControlSpace);
    flowControlSpace->setControlSamplerAllocator(
        [](const ompl::control::ControlSpace *space) -> ompl::control::ControlSamplerPtr
        { return std::make_shared<ompl::control::RealVectorControlUniformSampler>(space); });
 
    ompl::control::RealVectorControlUniformSampler jumpControlSampler(
        jumpControlSpace);  // Doesn't do anything because the bounds for jump input are just [0, 0], but here for
                            // demonstration
    jumpControlSpace->setControlSamplerAllocator(
        [](const ompl::control::ControlSpace *space) -> ompl::control::ControlSamplerPtr
        { return std::make_shared<ompl::control::RealVectorControlUniformSampler>(space); });
 
    ompl::control::ControlSpacePtr flowControlSpacePtr(flowControlSpace);
    ompl::control::ControlSpacePtr jumpControlSpacePtr(jumpControlSpace);
 
    ompl::control::CompoundControlSpace *controlSpace = new ompl::control::CompoundControlSpace(hybridSpacePtr);
    controlSpace->addSubspace(flowControlSpacePtr);
    controlSpace->addSubspace(jumpControlSpacePtr);
 
    ompl::control::ControlSpacePtr controlSpacePtr(controlSpace);
 
    // Construct a space information instance for this state space
    ompl::control::SpaceInformationPtr si(new ompl::control::SpaceInformation(hybridSpacePtr, controlSpacePtr));
    ompl::control::ODESolverPtr odeSolver(new ompl::control::ODEBasicSolver<>(si, &flowODE));
 
    si->setStatePropagator(ompl::control::ODESolver::getStatePropagator(odeSolver));
    si->setPropagationStepSize(0.01);
    si->setup();
 
    // Create a problem instance
    ompl::base::ProblemDefinitionPtr pdef(new ompl::base::ProblemDefinition(si));
 
    std::vector<ompl::base::ScopedState<>> startStates;
    std::vector<double> startXs = {0.5, 1, 2, 3.5, 4, 4.5};
 
    for (std::size_t i = 0; i < startXs.size(); i++)
    {
        startStates.push_back(ompl::base::ScopedState<>(hybridSpacePtr));
        startStates.back()
            ->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[0] = startXs[i];
        startStates.back()
            ->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[1] = 0;
        startStates.back()
            ->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[2] = 0;
        startStates.back()
            ->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[3] = 0;
        startStates.back()
            ->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[4] = 0;
        startStates.back()
            ->as<ompl::base::HybridStateSpace::StateType>()
            ->as<ompl::base::RealVectorStateSpace::StateType>(0)
            ->values[5] = -9.81;
        pdef->addStartState(startStates.back());
    }
 
    // Set goal state to be on floor with a zero velocity, and tolerance of 0.1
    std::shared_ptr<EuclideanGoalRegion> goal = std::make_shared<EuclideanGoalRegion>(si);
 
    // Set the goal region
    pdef->setGoal(goal);
 
    ompl::control::HyRRT cHyRRT(si);
 
    // Set the problem instance for our planner to solve
    cHyRRT.setProblemDefinition(pdef);
    cHyRRT.setup();
 
    // Set parameters
    cHyRRT.setDiscreteSimulator(discreteSimulator);
    cHyRRT.setDistanceFunction(distanceFunc);
    cHyRRT.setFlowSet(flowSet);
    cHyRRT.setJumpSet(jumpSet);
    cHyRRT.setTm(0.5);
    cHyRRT.setFlowStepDuration(0.01);
    cHyRRT.setUnsafeSet(unsafeSet);
 
    // attempt to solve the planning problem within 15 seconds
    ompl::time::point t0 = ompl::time::now();
    ompl::base::PlannerStatus solved = cHyRRT.solve(ompl::base::timedPlannerTerminationCondition(15));
    double planTime = ompl::time::seconds(ompl::time::now() - t0);
 
    if (solved)  // If either approximate or exact solution has beenf ound
        OMPL_INFORM("Solution found in %f seconds", planTime);
    OMPL_INFORM("Solution status: %s", solved.asString().c_str());
 
    // print path
    pdef->getSolutionPath()->as<ompl::control::PathControl>()->printAsMatrix(std::cout);
}