TaskspaceImpedanceController.cpp

Go to the documentation of this file.

#include "TaskspaceImpedanceController.h"
 
#include <SimoxUtility/math/convert/mat4f_to_quat.h>
#include <VirtualRobot/MathTools.h>
 
#include <RobotAPI/components/units/RobotUnit/util/ControlThreadOutputBuffer.h>
 
#include <armarx/control/common/device.h>
 
#include "../utils.h"
 
namespace armarx::control::common::control_law
{
 
    void
    TaskspaceImpedanceController::initialize(const VirtualRobot::RobotNodeSetPtr& rns,
                                             const VirtualRobot::RobotNodeSetPtr& rtRns)
    {
        ARMARX_CHECK_NOT_NULL(rns);
        tcp = rns->getTCP();
        rtTCP = rtRns->getTCP();
        ARMARX_CHECK_NOT_NULL(tcp);
        ik.reset(new VirtualRobot::DifferentialIK(
            rtRns, rtRns->getRobot()->getRootNode(), VirtualRobot::JacobiProvider::eSVDDamped));
 
        numOfJoints = rns->getSize();
        I = Eigen::MatrixXf::Identity(numOfJoints, numOfJoints);
    }
 
    void
    TaskspaceImpedanceController::preactivateInit(const VirtualRobot::RobotNodeSetPtr& rns)
    {
    }
 
    void
    TaskspaceImpedanceController::firstRun()
    {
        ftsensor.reset();
    }
 
    // void
    // TaskspaceImpedanceController::updateFT(const FTConfig& c, RtStatus& rtStatus)
    // {
    //     /// run in rt thread
    //     ftsensor.updateStatus();
    //     if (c.reCalibrate)
    //     {
    //         ftsensor.calibrated.store(false);
    //         /// TODO how to toggle recalibration?
    //     }
    //     ftsensor.compensateTCPGravity(c);
    //     if (!ftsensor.calibrated.load())
    //     {
    //         if (ftsensor.calibrate(c, rtStatus.deltaT))
    //         {
    //             ftsensor.calibrated.store(true);
    //         }
    //     }
    //     else
    //     {
    //         rtStatus.currentForceTorque = ftsensor.getFilteredForceTorque(c);
    //     }
    // }
 
    void
    TaskspaceImpedanceController::run(Config& c, RtStatus& rtStatus)
    {
        /// run in rt thread
        rtStatus.currentPose = rtTCP->getPoseInRootFrame();
 
        /// ---------------------------- safety guard by FT and target pose ------------------------
        rtStatus.poseDiffMatImp =
            c.desiredPose.block<3, 3>(0, 0) * rtStatus.currentPose.block<3, 3>(0, 0).transpose();
        rtStatus.oriDiffAngleAxis.fromRotationMatrix(rtStatus.poseDiffMatImp);
 
        /// this should not be moved to non rt, just in case non rt thread dies, rt still functions as safely
        if (not ftsensor.isSafe(c.ftConfig))
        {
            ARMARX_INFO << "FTGuard indicates RT not safe";
            c.desiredPose = rtStatus.desiredPose;
            rtStatus.rtSafe = false;
            rtStatus.rtTargetSafe = true;
        }
        else if ((c.desiredPose.block<3, 1>(0, 3) - rtStatus.currentPose.block<3, 1>(0, 3)).norm() >
                     c.safeDistanceMMToGoal or
                 std::fminf(rtStatus.oriDiffAngleAxis.angle(),
                            2 * M_PI - rtStatus.oriDiffAngleAxis.angle()) >
                     VirtualRobot::MathTools::deg2rad(c.safeRotAngleDegreeToGoal))
        {
            c.desiredPose = rtStatus.desiredPose;
            rtStatus.rtSafe = false;
            rtStatus.rtTargetSafe = false;
        }
        else
        {
            rtStatus.desiredPose = c.desiredPose;
            rtStatus.rtSafe = true;
            rtStatus.rtTargetSafe = true;
        }
 
        /// ------------------------------ compute jacobi ------------------------------------------
        rtStatus.jacobi =
            ik->getJacobianMatrix(rtTCP, VirtualRobot::IKSolver::CartesianSelection::All);
        rtStatus.jacobi.block(0, 0, 3, rtStatus.numJoints) =
            0.001 * rtStatus.jacobi.block(0, 0, 3, rtStatus.numJoints);
        ARMARX_CHECK_EQUAL(rtStatus.numJoints, rtStatus.jacobi.cols());
        ARMARX_CHECK_EQUAL(6, rtStatus.jacobi.rows());
 
        rtStatus.jtpinv =
            ik->computePseudoInverseJacobianMatrix(rtStatus.jacobi.transpose(), lambda);
        ARMARX_CHECK_EQUAL(rtStatus.numJoints, rtStatus.jtpinv.cols());
        ARMARX_CHECK_EQUAL(6, rtStatus.jtpinv.rows());
 
        /// ------------------------------ update velocity/twist -----------------------------------
        ARMARX_CHECK_EQUAL(rtStatus.numJoints, rtStatus.jointPos.rows());
        ARMARX_CHECK_EQUAL(rtStatus.numJoints, rtStatus.jointVel.rows());
        ARMARX_CHECK_EQUAL(rtStatus.numJoints, rtStatus.qvelFiltered.rows());
 
        rtStatus.qvelFiltered =
            (1 - c.qvelFilter) * rtStatus.qvelFiltered + c.qvelFilter * rtStatus.jointVel;
        rtStatus.currentTwist = rtStatus.jacobi * rtStatus.qvelFiltered;
 
        /// ------------------------------------- Impedance control --------------------------------
        /// calculate pose error between target pose and current pose
        /// !!! This is very important: you have to keep postion and orientation both
        ///     with UI unit (meter, radian) to calculate impedance force.
 
        rtStatus.poseDiffMatImp = rtStatus.desiredPose.block<3, 3>(0, 0) *
                                  rtStatus.currentPose.block<3, 3>(0, 0).transpose();
        rtStatus.poseErrorImp.head(3) = 0.001 * (rtStatus.desiredPose.block<3, 1>(0, 3) -
                                                 rtStatus.currentPose.block<3, 1>(0, 3));
        rtStatus.poseErrorImp.tail(3) =
            VirtualRobot::MathTools::eigen3f2rpy(rtStatus.poseDiffMatImp);
 
        rtStatus.forceImpedance = c.kpImpedance.cwiseProduct(rtStatus.poseErrorImp) -
                                  c.kdImpedance.cwiseProduct(rtStatus.currentTwist);
 
        /// ----------------------------- Nullspace PD Control -------------------------------------
        ARMARX_CHECK_EQUAL(rtStatus.numJoints, c.kpNullspace.rows());
        ARMARX_CHECK_EQUAL(rtStatus.numJoints, rtStatus.nullspaceTorque.rows());
        ARMARX_CHECK_EQUAL(rtStatus.numJoints, c.desiredNullspaceJointAngles.value().size());
        rtStatus.nullspaceTorque =
            c.kpNullspace.cwiseProduct(c.desiredNullspaceJointAngles.value() - rtStatus.jointPos) -
            c.kdNullspace.cwiseProduct(rtStatus.qvelFiltered);
 
        /// ----------------------------- Map TS target force to JS --------------------------------
        ARMARX_CHECK_EQUAL(rtStatus.numJoints, rtStatus.desiredJointTorques.rows());
        rtStatus.desiredJointTorques =
            rtStatus.jacobi.transpose() * rtStatus.forceImpedance +
            (I - rtStatus.jacobi.transpose() * rtStatus.jtpinv) * rtStatus.nullspaceTorque;
 
        /// ----------------------------- write torque target  -------------------------------------
        for (int i = 0; i < rtStatus.desiredJointTorques.rows(); ++i)
        {
            rtStatus.desiredJointTorques(i) =
                std::clamp(rtStatus.desiredJointTorques(i), -c.torqueLimit, c.torqueLimit);
        }
    }
 
    void
    TaskspaceImpedanceController::RtStatus::reset(const unsigned int nDoF)
    {
        /// This function can be called before the RT thread.
        /// base
        jointPosition.resize(nDoF, 0.);
        jointVelocity.resize(nDoF, 0.);
        jointTorque.resize(nDoF, 0.);
        jointPos.setZero(nDoF);
        jointVel.setZero(nDoF);
        jointTor.setZero(nDoF);
        deltaT = 0.0;
        numJoints = nDoF;
 
        /// targets
        desiredJointTorques.setZero(nDoF);
        nullspaceTorque.setZero(nDoF);
 
        /// force torque
        currentForceTorque.setZero();
 
        /// task space variables
        forceImpedance.setZero();
 
        /// current status
        qvelFiltered.setZero(nDoF);
        currentPose.setZero();
        currentTwist.setZero();
        desiredPose.setZero();
 
        /// intermediate results
        poseDiffMatImp.setZero();
        poseErrorImp.setZero();
        oriDiffAngleAxis = Eigen::AngleAxisf::Identity();
 
        /// others
        jacobi.setZero(6, nDoF);
        jtpinv.setZero(6, nDoF);
        rtSafe = false;
        rtTargetSafe = true;
    }
 
    void
    TaskspaceImpedanceController::RtStatus::rtPreActivate(const Eigen::Matrix4f& currentTCPPose)
    {
        /// !!!! TO BE UPDATED IN PREACTIVATE !!!!
        /// only then the up-to-date robot joint information is available
        currentPose = currentTCPPose;
        desiredPose = currentTCPPose;
    }
 
} // namespace armarx::control::common::control_law