mirror of
https://github.com/bulletphysics/bullet3
synced 2024-12-15 22:20:12 +00:00
224 lines
7.2 KiB
C++
224 lines
7.2 KiB
C++
#include "IKTrajectoryHelper.h"
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#include "BussIK/Node.h"
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#include "BussIK/Tree.h"
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#include "BussIK/Jacobian.h"
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#include "BussIK/VectorRn.h"
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#include "BussIK/MatrixRmn.h"
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#include "Bullet3Common/b3AlignedObjectArray.h"
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#include "BulletDynamics/Featherstone/btMultiBody.h"
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#define RADIAN(X) ((X)*RadiansToDegrees)
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//use BussIK and Reflexxes to convert from Cartesian endeffector future target to
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//joint space positions at each real-time (simulation) step
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struct IKTrajectoryHelperInternalData
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{
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VectorR3 m_endEffectorTargetPosition;
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VectorRn m_nullSpaceVelocity;
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VectorRn m_dampingCoeff;
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b3AlignedObjectArray<Node*> m_ikNodes;
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IKTrajectoryHelperInternalData()
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{
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m_endEffectorTargetPosition.SetZero();
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m_nullSpaceVelocity.SetZero();
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m_dampingCoeff.SetZero();
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}
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};
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IKTrajectoryHelper::IKTrajectoryHelper()
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{
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m_data = new IKTrajectoryHelperInternalData;
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}
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IKTrajectoryHelper::~IKTrajectoryHelper()
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{
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delete m_data;
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}
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bool IKTrajectoryHelper::computeIK(const double endEffectorTargetPosition[3],
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const double endEffectorTargetOrientation[4],
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const double endEffectorWorldPosition[3],
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const double endEffectorWorldOrientation[4],
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const double* q_current, int numQ,int endEffectorIndex,
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double* q_new, int ikMethod, const double* linear_jacobian, const double* angular_jacobian, int jacobian_size, const double dampIk[6])
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{
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bool useAngularPart = (ikMethod==IK2_VEL_DLS_WITH_ORIENTATION || ikMethod==IK2_VEL_DLS_WITH_ORIENTATION_NULLSPACE
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|| ikMethod==IK2_VEL_SDLS_WITH_ORIENTATION) ? true : false;
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Jacobian ikJacobian(useAngularPart,numQ);
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ikJacobian.Reset();
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bool UseJacobianTargets1 = false;
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if ( UseJacobianTargets1 ) {
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ikJacobian.SetJtargetActive();
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}
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else {
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ikJacobian.SetJendActive();
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}
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VectorR3 targets;
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targets.Set(endEffectorTargetPosition[0],endEffectorTargetPosition[1],endEffectorTargetPosition[2]);
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ikJacobian.ComputeJacobian(&targets); // Set up Jacobian and deltaS vectors
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// Set one end effector world position from Bullet
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VectorRn deltaS(3);
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for (int i = 0; i < 3; ++i)
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{
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deltaS.Set(i,dampIk[i]*(endEffectorTargetPosition[i]-endEffectorWorldPosition[i]));
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}
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// Set one end effector world orientation from Bullet
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VectorRn deltaR(3);
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if (useAngularPart)
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{
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btQuaternion startQ(endEffectorWorldOrientation[0],endEffectorWorldOrientation[1],endEffectorWorldOrientation[2],endEffectorWorldOrientation[3]);
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btQuaternion endQ(endEffectorTargetOrientation[0],endEffectorTargetOrientation[1],endEffectorTargetOrientation[2],endEffectorTargetOrientation[3]);
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btQuaternion deltaQ = endQ*startQ.inverse();
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float angle = deltaQ.getAngle();
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btVector3 axis = deltaQ.getAxis();
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if (angle > PI) {
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angle -= 2.0*PI;
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}
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else if (angle < -PI) {
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angle += 2.0*PI;
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}
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float angleDot = angle;
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btVector3 angularVel = angleDot*axis.normalize();
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for (int i = 0; i < 3; ++i)
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{
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deltaR.Set(i,dampIk[i+3]*angularVel[i]);
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}
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}
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{
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if (useAngularPart)
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{
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VectorRn deltaC(6);
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MatrixRmn completeJacobian(6,numQ);
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for (int i = 0; i < 3; ++i)
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{
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deltaC.Set(i,deltaS[i]);
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deltaC.Set(i+3,deltaR[i]);
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for (int j = 0; j < numQ; ++j)
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{
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completeJacobian.Set(i,j,linear_jacobian[i*numQ+j]);
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completeJacobian.Set(i+3,j,angular_jacobian[i*numQ+j]);
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}
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}
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ikJacobian.SetDeltaS(deltaC);
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ikJacobian.SetJendTrans(completeJacobian);
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} else
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{
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VectorRn deltaC(3);
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MatrixRmn completeJacobian(3,numQ);
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for (int i = 0; i < 3; ++i)
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{
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deltaC.Set(i,deltaS[i]);
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for (int j = 0; j < numQ; ++j)
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{
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completeJacobian.Set(i,j,linear_jacobian[i*numQ+j]);
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}
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}
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ikJacobian.SetDeltaS(deltaC);
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ikJacobian.SetJendTrans(completeJacobian);
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}
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}
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// Calculate the change in theta values
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switch (ikMethod) {
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case IK2_JACOB_TRANS:
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ikJacobian.CalcDeltaThetasTranspose(); // Jacobian transpose method
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break;
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case IK2_DLS:
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case IK2_VEL_DLS_WITH_ORIENTATION:
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case IK2_VEL_DLS:
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//ikJacobian.CalcDeltaThetasDLS(); // Damped least squares method
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assert(m_data->m_dampingCoeff.GetLength()==numQ);
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ikJacobian.CalcDeltaThetasDLS2(m_data->m_dampingCoeff);
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break;
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case IK2_VEL_DLS_WITH_NULLSPACE:
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case IK2_VEL_DLS_WITH_ORIENTATION_NULLSPACE:
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assert(m_data->m_nullSpaceVelocity.GetLength()==numQ);
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ikJacobian.CalcDeltaThetasDLSwithNullspace(m_data->m_nullSpaceVelocity);
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break;
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case IK2_DLS_SVD:
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ikJacobian.CalcDeltaThetasDLSwithSVD();
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break;
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case IK2_PURE_PSEUDO:
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ikJacobian.CalcDeltaThetasPseudoinverse(); // Pure pseudoinverse method
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break;
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case IK2_SDLS:
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case IK2_VEL_SDLS:
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case IK2_VEL_SDLS_WITH_ORIENTATION:
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ikJacobian.CalcDeltaThetasSDLS(); // Selectively damped least squares method
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break;
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default:
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ikJacobian.ZeroDeltaThetas();
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break;
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}
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// Use for velocity IK, update theta dot
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//ikJacobian.UpdateThetaDot();
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// Use for position IK, incrementally update theta
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//ikJacobian.UpdateThetas();
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// Apply the change in the theta values
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//ikJacobian.UpdatedSClampValue(&targets);
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for (int i=0;i<numQ;i++)
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{
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// Use for velocity IK
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q_new[i] = ikJacobian.dTheta[i] + q_current[i];
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// Use for position IK
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//q_new[i] = m_data->m_ikNodes[i]->GetTheta();
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}
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return true;
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}
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bool IKTrajectoryHelper::computeNullspaceVel(int numQ, const double* q_current, const double* lower_limit, const double* upper_limit, const double* joint_range, const double* rest_pose)
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{
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m_data->m_nullSpaceVelocity.SetLength(numQ);
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m_data->m_nullSpaceVelocity.SetZero();
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// TODO: Expose the coefficents of the null space term so that the user can choose to balance the null space task and the IK target task.
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// Can also adaptively adjust the coefficients based on the residual of the null space velocity in the IK target task space.
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double stayCloseToZeroGain = 0.001;
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double stayAwayFromLimitsGain = 10.0;
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// Stay close to zero
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for (int i = 0; i < numQ; ++i)
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{
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m_data->m_nullSpaceVelocity[i] = stayCloseToZeroGain * (rest_pose[i]-q_current[i]);
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}
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// Stay away from joint limits
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for (int i = 0; i < numQ; ++i) {
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if (q_current[i] > upper_limit[i]) {
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m_data->m_nullSpaceVelocity[i] += stayAwayFromLimitsGain * (upper_limit[i] - q_current[i]) / joint_range[i];
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}
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if (q_current[i] < lower_limit[i]) {
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m_data->m_nullSpaceVelocity[i] += stayAwayFromLimitsGain * (lower_limit[i] - q_current[i]) / joint_range[i];
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}
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}
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return true;
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}
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bool IKTrajectoryHelper::setDampingCoeff(int numQ, const double* coeff)
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{
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m_data->m_dampingCoeff.SetLength(numQ);
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m_data->m_dampingCoeff.SetZero();
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for (int i = 0; i < numQ; ++i)
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{
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m_data->m_dampingCoeff[i] = coeff[i];
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}
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return true;
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}
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