blender/intern/itasc/Distance.cpp

325 lines
8.9 KiB
C++

/** \file itasc/Distance.cpp
* \ingroup itasc
*/
/*
* Distance.cpp
*
* Created on: Jan 30, 2009
* Author: rsmits
*/
#include "Distance.hpp"
#include "kdl/kinfam_io.hpp"
#include <math.h>
#include <string.h>
namespace iTaSC
{
// a distance constraint is characterized by 5 values: alpha, tolerance, K, yd, yddot
static const unsigned int distanceCacheSize = sizeof(double)*5 + sizeof(e_scalar)*6;
Distance::Distance(double armlength, double accuracy, unsigned int maximum_iterations):
ConstraintSet(1,accuracy,maximum_iterations),
m_chiKdl(6),m_jac(6),m_cache(NULL),
m_distCCh(-1),m_distCTs(0)
{
m_chain.addSegment(Segment(Joint(Joint::RotZ)));
m_chain.addSegment(Segment(Joint(Joint::RotX)));
m_chain.addSegment(Segment(Joint(Joint::TransY)));
m_chain.addSegment(Segment(Joint(Joint::RotZ)));
m_chain.addSegment(Segment(Joint(Joint::RotY)));
m_chain.addSegment(Segment(Joint(Joint::RotX)));
m_fksolver = new KDL::ChainFkSolverPos_recursive(m_chain);
m_jacsolver = new KDL::ChainJntToJacSolver(m_chain);
m_Cf(0,2)=1.0;
m_alpha = 1.0;
m_tolerance = 0.05;
m_maxerror = armlength/2.0;
m_K = 20.0;
m_Wy(0) = m_alpha/*/(m_tolerance*m_K)*/;
m_yddot = m_nextyddot = 0.0;
m_yd = m_nextyd = KDL::epsilon;
memset(&m_data, 0, sizeof(m_data));
// initialize the data with normally fixed values
m_data.id = ID_DISTANCE;
m_values.id = ID_DISTANCE;
m_values.number = 1;
m_values.alpha = m_alpha;
m_values.feedback = m_K;
m_values.tolerance = m_tolerance;
m_values.values = &m_data;
}
Distance::~Distance()
{
delete m_fksolver;
delete m_jacsolver;
}
bool Distance::computeChi(Frame& pose)
{
double dist, alpha, beta, gamma;
dist = pose.p.Norm();
Rotation basis;
if (dist < KDL::epsilon) {
// distance is almost 0, no need for initial rotation
m_chi(0) = 0.0;
m_chi(1) = 0.0;
} else {
// find the XZ angles that bring the Y axis to point to init_pose.p
Vector axis(pose.p/dist);
beta = 0.0;
if (fabs(axis(2)) > 1-KDL::epsilon) {
// direction is aligned on Z axis, just rotation on X
alpha = 0.0;
gamma = KDL::sign(axis(2))*KDL::PI/2;
} else {
alpha = -KDL::atan2(axis(0), axis(1));
gamma = KDL::atan2(axis(2), KDL::sqrt(KDL::sqr(axis(0))+KDL::sqr(axis(1))));
}
// rotation after first 2 joints
basis = Rotation::EulerZYX(alpha, beta, gamma);
m_chi(0) = alpha;
m_chi(1) = gamma;
}
m_chi(2) = dist;
basis = basis.Inverse()*pose.M;
basis.GetEulerZYX(alpha, beta, gamma);
// alpha = rotation on Z
// beta = rotation on Y
// gamma = rotation on X in that order
// it corresponds to the joint order, so just assign
m_chi(3) = alpha;
m_chi(4) = beta;
m_chi(5) = gamma;
return true;
}
bool Distance::initialise(Frame& init_pose)
{
// we will initialize m_chi to values that match the pose
m_externalPose=init_pose;
computeChi(m_externalPose);
// get current Jf and update internal pose
updateJacobian();
return true;
}
bool Distance::closeLoop()
{
if (!Equal(m_internalPose.Inverse()*m_externalPose,F_identity,m_threshold)){
computeChi(m_externalPose);
updateJacobian();
}
return true;
}
void Distance::initCache(Cache *_cache)
{
m_cache = _cache;
m_distCCh = -1;
if (m_cache) {
// create one channel for the coordinates
m_distCCh = m_cache->addChannel(this, "Xf", distanceCacheSize);
// save initial constraint in cache position 0
pushDist(0);
}
}
void Distance::pushDist(CacheTS timestamp)
{
if (m_distCCh >= 0) {
double *item = (double*)m_cache->addCacheItem(this, m_distCCh, timestamp, NULL, distanceCacheSize);
if (item) {
*item++ = m_K;
*item++ = m_tolerance;
*item++ = m_yd;
*item++ = m_yddot;
*item++ = m_alpha;
memcpy(item, &m_chi[0], 6*sizeof(e_scalar));
}
m_distCTs = timestamp;
}
}
bool Distance::popDist(CacheTS timestamp)
{
if (m_distCCh >= 0) {
double *item = (double*)m_cache->getPreviousCacheItem(this, m_distCCh, &timestamp);
if (item && timestamp != m_distCTs) {
m_values.feedback = m_K = *item++;
m_values.tolerance = m_tolerance = *item++;
m_yd = *item++;
m_yddot = *item++;
m_values.alpha = m_alpha = *item++;
memcpy(&m_chi[0], item, 6*sizeof(e_scalar));
m_distCTs = timestamp;
m_Wy(0) = m_alpha/*/(m_tolerance*m_K)*/;
updateJacobian();
}
return (item) ? true : false;
}
return true;
}
void Distance::pushCache(const Timestamp& timestamp)
{
if (!timestamp.substep && timestamp.cache)
pushDist(timestamp.cacheTimestamp);
}
void Distance::updateKinematics(const Timestamp& timestamp)
{
if (timestamp.interpolate) {
//the internal pose and Jf is already up to date (see model_update)
//update the desired output based on yddot
if (timestamp.substep) {
m_yd += m_yddot*timestamp.realTimestep;
if (m_yd < KDL::epsilon)
m_yd = KDL::epsilon;
} else {
m_yd = m_nextyd;
m_yddot = m_nextyddot;
}
}
pushCache(timestamp);
}
void Distance::updateJacobian()
{
for(unsigned int i=0;i<6;i++)
m_chiKdl(i)=m_chi(i);
m_fksolver->JntToCart(m_chiKdl,m_internalPose);
m_jacsolver->JntToJac(m_chiKdl,m_jac);
changeRefPoint(m_jac,-m_internalPose.p,m_jac);
for(unsigned int i=0;i<6;i++)
for(unsigned int j=0;j<6;j++)
m_Jf(i,j)=m_jac(i,j);
}
bool Distance::setControlParameters(struct ConstraintValues* _values, unsigned int _nvalues, double timestep)
{
int action = 0;
int i;
ConstraintSingleValue* _data;
while (_nvalues > 0) {
if (_values->id == ID_DISTANCE) {
if ((_values->action & ACT_ALPHA) && _values->alpha >= 0.0) {
m_alpha = _values->alpha;
action |= ACT_ALPHA;
}
if ((_values->action & ACT_TOLERANCE) && _values->tolerance > KDL::epsilon) {
m_tolerance = _values->tolerance;
action |= ACT_TOLERANCE;
}
if ((_values->action & ACT_FEEDBACK) && _values->feedback > KDL::epsilon) {
m_K = _values->feedback;
action |= ACT_FEEDBACK;
}
for (_data = _values->values, i=0; i<_values->number; i++, _data++) {
if (_data->id == ID_DISTANCE) {
switch (_data->action & (ACT_VALUE|ACT_VELOCITY)) {
case 0:
// no indication, keep current values
break;
case ACT_VELOCITY:
// only the velocity is given estimate the new value by integration
_data->yd = m_yd+_data->yddot*timestep;
// walkthrough for negative value correction
case ACT_VALUE:
// only the value is given, estimate the velocity from previous value
if (_data->yd < KDL::epsilon)
_data->yd = KDL::epsilon;
m_nextyd = _data->yd;
// if the user sets the value, we assume future velocity is zero
// (until the user changes the value again)
m_nextyddot = (_data->action & ACT_VALUE) ? 0.0 : _data->yddot;
if (timestep>0.0) {
m_yddot = (_data->yd-m_yd)/timestep;
} else {
// allow the user to change target instantenously when this function
// if called from setControlParameter with timestep = 0
m_yddot = m_nextyddot;
m_yd = m_nextyd;
}
break;
case (ACT_VALUE|ACT_VELOCITY):
// the user should not set the value and velocity at the same time.
// In this case, we will assume that he want to set the future value
// and we compute the current value to match the velocity
if (_data->yd < KDL::epsilon)
_data->yd = KDL::epsilon;
m_yd = _data->yd - _data->yddot*timestep;
if (m_yd < KDL::epsilon)
m_yd = KDL::epsilon;
m_nextyd = _data->yd;
m_nextyddot = _data->yddot;
if (timestep>0.0) {
m_yddot = (_data->yd-m_yd)/timestep;
} else {
m_yd = m_nextyd;
m_yddot = m_nextyddot;
}
break;
}
}
}
}
_nvalues--;
_values++;
}
if (action & (ACT_TOLERANCE|ACT_FEEDBACK|ACT_ALPHA)) {
// recompute the weight
m_Wy(0) = m_alpha/*/(m_tolerance*m_K)*/;
}
return true;
}
const ConstraintValues* Distance::getControlParameters(unsigned int* _nvalues)
{
*(double*)&m_data.y = m_chi(2);
*(double*)&m_data.ydot = m_ydot(0);
m_data.yd = m_yd;
m_data.yddot = m_yddot;
m_data.action = 0;
m_values.action = 0;
if (_nvalues)
*_nvalues=1;
return &m_values;
}
void Distance::updateControlOutput(const Timestamp& timestamp)
{
bool cacheAvail = true;
if (!timestamp.substep) {
if (!timestamp.reiterate)
cacheAvail = popDist(timestamp.cacheTimestamp);
}
if (m_constraintCallback && (m_substep || (!timestamp.reiterate && !timestamp.substep))) {
// initialize first callback the application to get the current values
*(double*)&m_data.y = m_chi(2);
*(double*)&m_data.ydot = m_ydot(0);
m_data.yd = m_yd;
m_data.yddot = m_yddot;
m_data.action = 0;
m_values.action = 0;
if ((*m_constraintCallback)(timestamp, &m_values, 1, m_constraintParam)) {
setControlParameters(&m_values, 1, timestamp.realTimestep);
}
}
if (!cacheAvail || !timestamp.interpolate) {
// first position in cache: set the desired output immediately as we cannot interpolate
m_yd = m_nextyd;
m_yddot = m_nextyddot;
}
double error = m_yd-m_chi(2);
if (KDL::Norm(error) > m_maxerror)
error = KDL::sign(error)*m_maxerror;
m_ydot(0)=m_yddot+m_K*error;
}
}