OMForceTorque.cpp

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#include "OMForceTorque.h"

#include <Rcs_typedef.h>
#include <Rcs_math.h>
#include <Rcs_MatNd.h>

#include <limits>
#include <vector>
#include <stdexcept>


namespace Rcs
{

OMForceTorque::OMForceTorque(
    RcsGraph* graph, const char* sensorName, double max_force, bool transformToWorldFrame
) : max_force(max_force), transformToWorldFrame(transformToWorldFrame)
{
    sensor = RcsGraph_getSensorByName(graph, sensorName);
    if (!sensor) {
        throw std::invalid_argument("Sensor not found: " + std::string(sensorName));
    }
    max_torque = std::numeric_limits<double>::infinity(); // [Nm]
}

OMForceTorque::~OMForceTorque() = default;

unsigned int OMForceTorque::getStateDim() const
{
    return 6;  // 3 forces, 3 torques
}

unsigned int OMForceTorque::getVelocityDim() const
{
    // no derivative
    return 0;
}

void OMForceTorque::computeObservation(double* state, double* velocity, const MatNd* currentAction, double dt) const
{
    if (transformToWorldFrame)
    {
        // Sensor frame: A_SI = A_SB * A_BI
        const HTr* A_SB = sensor->offset; // body -> sensor
        HTr A_SI;
        HTr_transform(&A_SI, sensor->body->A_BI, A_SB);
        
        // Force / torque in world frame: I_f = (A_SI)^T*S_f
        double* S_force = &sensor->rawData->ele[0];
        double* S_torque = &sensor->rawData->ele[getStateDim()/2];
        double I_force[getStateDim()/2], I_torque[getStateDim()/2];
        Vec3d_transRotate(I_force, A_SI.rot, S_force);  Vec3d_transRotate(I_torque, A_SI.rot, S_torque);
        
        VecNd_copy(state, I_force, getStateDim()/2);
        VecNd_copy(state + getStateDim()/2, I_torque, getStateDim()/2);
    }
    
    else {
        VecNd_copy(state, sensor->rawData->ele, getStateDim());
    }
}

void OMForceTorque::getLimits(double* minState, double* maxState, double* maxVelocity) const
{
    // Forces
    for (size_t i = 0; i < getStateDim()/2; ++i) {
        minState[i] = -max_force;
        maxState[i] = max_force;
    }
    // Torques
    for (size_t i = getStateDim()/2; i < getStateDim(); ++i) {
        minState[i] = -max_torque;
        maxState[i] = max_torque;
    }
}

std::vector<std::string> OMForceTorque::getStateNames() const
{
    std::string sn = sensor->name;
    return {sn + "_Fx", sn + "_Fy", sn + "_Fz", sn + "_Tx", sn + "_Ty", sn + "_Tz",};
}

} /* namespace Rcs */