323 lines
8.9 KiB
C++
323 lines
8.9 KiB
C++
/* SPDX-FileCopyrightText: 2009 Ruben Smits
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*
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* SPDX-License-Identifier: LGPL-2.1-or-later */
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/** \file
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* \ingroup intern_itasc
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*/
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#include "Distance.hpp"
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#include "kdl/kinfam_io.hpp"
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#include <math.h>
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#include <string.h>
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namespace iTaSC
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{
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// a distance constraint is characterized by 5 values: alpha, tolerance, K, yd, yddot
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static const unsigned int distanceCacheSize = sizeof(double)*5 + sizeof(e_scalar)*6;
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Distance::Distance(double armlength, double accuracy, unsigned int maximum_iterations):
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ConstraintSet(1,accuracy,maximum_iterations),
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m_chiKdl(6),m_jac(6),m_cache(NULL),
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m_distCCh(-1),m_distCTs(0)
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{
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m_chain.addSegment(Segment(Joint(Joint::RotZ)));
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m_chain.addSegment(Segment(Joint(Joint::RotX)));
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m_chain.addSegment(Segment(Joint(Joint::TransY)));
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m_chain.addSegment(Segment(Joint(Joint::RotZ)));
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m_chain.addSegment(Segment(Joint(Joint::RotY)));
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m_chain.addSegment(Segment(Joint(Joint::RotX)));
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m_fksolver = new KDL::ChainFkSolverPos_recursive(m_chain);
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m_jacsolver = new KDL::ChainJntToJacSolver(m_chain);
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m_Cf(0,2)=1.0;
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m_alpha = 1.0;
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m_tolerance = 0.05;
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m_maxerror = armlength/2.0;
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m_K = 20.0;
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m_Wy(0) = m_alpha/*/(m_tolerance*m_K)*/;
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m_yddot = m_nextyddot = 0.0;
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m_yd = m_nextyd = KDL::epsilon;
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memset(&m_data, 0, sizeof(m_data));
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// initialize the data with normally fixed values
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m_data.id = ID_DISTANCE;
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m_values.id = ID_DISTANCE;
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m_values.number = 1;
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m_values.alpha = m_alpha;
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m_values.feedback = m_K;
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m_values.tolerance = m_tolerance;
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m_values.values = &m_data;
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}
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Distance::~Distance()
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{
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delete m_fksolver;
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delete m_jacsolver;
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}
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bool Distance::computeChi(Frame& pose)
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{
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double dist, alpha, beta, gamma;
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dist = pose.p.Norm();
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Rotation basis;
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if (dist < KDL::epsilon) {
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// distance is almost 0, no need for initial rotation
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m_chi(0) = 0.0;
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m_chi(1) = 0.0;
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} else {
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// find the XZ angles that bring the Y axis to point to init_pose.p
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Vector axis(pose.p/dist);
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beta = 0.0;
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if (fabs(axis(2)) > 1-KDL::epsilon) {
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// direction is aligned on Z axis, just rotation on X
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alpha = 0.0;
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gamma = KDL::sign(axis(2))*KDL::PI/2;
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} else {
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alpha = -KDL::atan2(axis(0), axis(1));
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gamma = KDL::atan2(axis(2), KDL::sqrt(KDL::sqr(axis(0))+KDL::sqr(axis(1))));
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}
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// rotation after first 2 joints
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basis = Rotation::EulerZYX(alpha, beta, gamma);
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m_chi(0) = alpha;
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m_chi(1) = gamma;
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}
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m_chi(2) = dist;
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basis = basis.Inverse()*pose.M;
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basis.GetEulerZYX(alpha, beta, gamma);
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// alpha = rotation on Z
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// beta = rotation on Y
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// gamma = rotation on X in that order
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// it corresponds to the joint order, so just assign
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m_chi(3) = alpha;
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m_chi(4) = beta;
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m_chi(5) = gamma;
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return true;
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}
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bool Distance::initialise(Frame& init_pose)
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{
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// we will initialize m_chi to values that match the pose
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m_externalPose=init_pose;
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computeChi(m_externalPose);
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// get current Jf and update internal pose
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updateJacobian();
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return true;
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}
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bool Distance::closeLoop()
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{
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if (!Equal(m_internalPose.Inverse()*m_externalPose,F_identity,m_threshold)){
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computeChi(m_externalPose);
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updateJacobian();
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}
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return true;
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}
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void Distance::initCache(Cache *_cache)
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{
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m_cache = _cache;
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m_distCCh = -1;
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if (m_cache) {
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// create one channel for the coordinates
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m_distCCh = m_cache->addChannel(this, "Xf", distanceCacheSize);
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// save initial constraint in cache position 0
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pushDist(0);
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}
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}
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void Distance::pushDist(CacheTS timestamp)
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{
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if (m_distCCh >= 0) {
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double *item = (double*)m_cache->addCacheItem(this, m_distCCh, timestamp, NULL, distanceCacheSize);
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if (item) {
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*item++ = m_K;
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*item++ = m_tolerance;
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*item++ = m_yd;
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*item++ = m_yddot;
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*item++ = m_alpha;
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memcpy(item, &m_chi[0], 6*sizeof(e_scalar));
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}
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m_distCTs = timestamp;
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}
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}
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bool Distance::popDist(CacheTS timestamp)
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{
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if (m_distCCh >= 0) {
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double *item = (double*)m_cache->getPreviousCacheItem(this, m_distCCh, ×tamp);
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if (item && timestamp != m_distCTs) {
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m_values.feedback = m_K = *item++;
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m_values.tolerance = m_tolerance = *item++;
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m_yd = *item++;
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m_yddot = *item++;
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m_values.alpha = m_alpha = *item++;
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memcpy(&m_chi[0], item, 6*sizeof(e_scalar));
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m_distCTs = timestamp;
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m_Wy(0) = m_alpha/*/(m_tolerance*m_K)*/;
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updateJacobian();
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}
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return (item) ? true : false;
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}
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return true;
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}
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void Distance::pushCache(const Timestamp& timestamp)
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{
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if (!timestamp.substep && timestamp.cache)
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pushDist(timestamp.cacheTimestamp);
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}
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void Distance::updateKinematics(const Timestamp& timestamp)
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{
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if (timestamp.interpolate) {
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//the internal pose and Jf is already up to date (see model_update)
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//update the desired output based on yddot
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if (timestamp.substep) {
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m_yd += m_yddot*timestamp.realTimestep;
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if (m_yd < KDL::epsilon)
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m_yd = KDL::epsilon;
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} else {
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m_yd = m_nextyd;
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m_yddot = m_nextyddot;
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}
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}
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pushCache(timestamp);
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}
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void Distance::updateJacobian()
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{
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for(unsigned int i=0;i<6;i++)
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m_chiKdl[i]=m_chi[i];
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m_fksolver->JntToCart(m_chiKdl,m_internalPose);
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m_jacsolver->JntToJac(m_chiKdl,m_jac);
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changeRefPoint(m_jac,-m_internalPose.p,m_jac);
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for(unsigned int i=0;i<6;i++)
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for(unsigned int j=0;j<6;j++)
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m_Jf(i,j)=m_jac(i,j);
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}
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bool Distance::setControlParameters(struct ConstraintValues* _values, unsigned int _nvalues, double timestep)
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{
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int action = 0;
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int i;
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ConstraintSingleValue* _data;
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while (_nvalues > 0) {
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if (_values->id == ID_DISTANCE) {
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if ((_values->action & ACT_ALPHA) && _values->alpha >= 0.0) {
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m_alpha = _values->alpha;
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action |= ACT_ALPHA;
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}
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if ((_values->action & ACT_TOLERANCE) && _values->tolerance > KDL::epsilon) {
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m_tolerance = _values->tolerance;
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action |= ACT_TOLERANCE;
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}
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if ((_values->action & ACT_FEEDBACK) && _values->feedback > KDL::epsilon) {
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m_K = _values->feedback;
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action |= ACT_FEEDBACK;
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}
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for (_data = _values->values, i=0; i<_values->number; i++, _data++) {
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if (_data->id == ID_DISTANCE) {
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switch (_data->action & (ACT_VALUE|ACT_VELOCITY)) {
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case 0:
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// no indication, keep current values
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break;
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case ACT_VELOCITY:
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// only the velocity is given estimate the new value by integration
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_data->yd = m_yd+_data->yddot*timestep;
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// walkthrough for negative value correction
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case ACT_VALUE:
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// only the value is given, estimate the velocity from previous value
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if (_data->yd < KDL::epsilon)
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_data->yd = KDL::epsilon;
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m_nextyd = _data->yd;
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// if the user sets the value, we assume future velocity is zero
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// (until the user changes the value again)
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m_nextyddot = (_data->action & ACT_VALUE) ? 0.0 : _data->yddot;
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if (timestep>0.0) {
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m_yddot = (_data->yd-m_yd)/timestep;
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} else {
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// allow the user to change target instantenously when this function
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// if called from setControlParameter with timestep = 0
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m_yddot = m_nextyddot;
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m_yd = m_nextyd;
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}
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break;
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case (ACT_VALUE|ACT_VELOCITY):
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// the user should not set the value and velocity at the same time.
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// In this case, we will assume that he want to set the future value
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// and we compute the current value to match the velocity
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if (_data->yd < KDL::epsilon)
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_data->yd = KDL::epsilon;
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m_yd = _data->yd - _data->yddot*timestep;
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if (m_yd < KDL::epsilon)
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m_yd = KDL::epsilon;
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m_nextyd = _data->yd;
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m_nextyddot = _data->yddot;
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if (timestep>0.0) {
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m_yddot = (_data->yd-m_yd)/timestep;
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} else {
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m_yd = m_nextyd;
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m_yddot = m_nextyddot;
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}
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break;
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}
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}
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}
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}
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_nvalues--;
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_values++;
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}
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if (action & (ACT_TOLERANCE|ACT_FEEDBACK|ACT_ALPHA)) {
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// recompute the weight
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m_Wy(0) = m_alpha/*/(m_tolerance*m_K)*/;
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}
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return true;
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}
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const ConstraintValues* Distance::getControlParameters(unsigned int* _nvalues)
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{
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*(double*)&m_data.y = m_chi(2);
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*(double*)&m_data.ydot = m_ydot(0);
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m_data.yd = m_yd;
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m_data.yddot = m_yddot;
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m_data.action = 0;
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m_values.action = 0;
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if (_nvalues)
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*_nvalues=1;
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return &m_values;
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}
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void Distance::updateControlOutput(const Timestamp& timestamp)
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{
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bool cacheAvail = true;
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if (!timestamp.substep) {
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if (!timestamp.reiterate)
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cacheAvail = popDist(timestamp.cacheTimestamp);
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}
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if (m_constraintCallback && (m_substep || (!timestamp.reiterate && !timestamp.substep))) {
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// initialize first callback the application to get the current values
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*(double*)&m_data.y = m_chi(2);
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*(double*)&m_data.ydot = m_ydot(0);
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m_data.yd = m_yd;
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m_data.yddot = m_yddot;
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m_data.action = 0;
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m_values.action = 0;
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if ((*m_constraintCallback)(timestamp, &m_values, 1, m_constraintParam)) {
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setControlParameters(&m_values, 1, timestamp.realTimestep);
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}
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}
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if (!cacheAvail || !timestamp.interpolate) {
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// first position in cache: set the desired output immediately as we cannot interpolate
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m_yd = m_nextyd;
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m_yddot = m_nextyddot;
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}
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double error = m_yd-m_chi(2);
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if (KDL::Norm(error) > m_maxerror)
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error = KDL::sign(error)*m_maxerror;
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m_ydot(0)=m_yddot+m_K*error;
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}
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}
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