MovingFrame.cpp

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/*
 * MovingFrame.cpp
 *
 *  Created on: Feb 10, 2009
 *      Author: benoitbolsee
 */
 
#include "MovingFrame.hpp"
#include <string.h>
namespace iTaSC{
 
static const unsigned int frameCacheSize = (sizeof(((Frame*)0)->p.data)+sizeof(((Frame*)0)->M.data))/sizeof(double);
 
MovingFrame::MovingFrame(const Frame& frame):UncontrolledObject(),
    m_function(NULL), m_param(NULL), m_velocity(), m_poseCCh(-1), m_poseCTs(0)
{
    m_internalPose = m_nextPose = frame;
    initialize(6, 1);
    e_matrix& Ju = m_JuArray[0];
    Ju = e_identity_matrix(6,6);
}
 
MovingFrame::~MovingFrame()
{
}
 
bool MovingFrame::finalize()
{
    updateJacobian();
    return true;
}
 
void MovingFrame::initCache(Cache *_cache)
{
    m_cache = _cache;
    m_poseCCh = -1;
    if (m_cache) {
        m_poseCCh = m_cache->addChannel(this,"pose",frameCacheSize*sizeof(double));
        // don't store the initial pose, it's causing unnecessary large velocity on the first step
        //pushInternalFrame(0);
    }
}
 
void MovingFrame::pushInternalFrame(CacheTS timestamp)
{
    if (m_poseCCh >= 0) {
        double buf[frameCacheSize];
        memcpy(buf, m_internalPose.p.data, sizeof(m_internalPose.p.data));
        memcpy(&buf[sizeof(m_internalPose.p.data)/sizeof(double)], m_internalPose.M.data, sizeof(m_internalPose.M.data));
 
        m_cache->addCacheVectorIfDifferent(this, m_poseCCh, timestamp, buf, frameCacheSize, KDL::epsilon);
        m_poseCTs = timestamp;
    }
}
 
// load pose just preceding timestamp
// return false if no cache position was found
bool MovingFrame::popInternalFrame(CacheTS timestamp)
{
    if (m_poseCCh >= 0) {
        char *item;
        item = (char *)m_cache->getPreviousCacheItem(this, m_poseCCh, &timestamp);
        if (item && m_poseCTs != timestamp) {
            memcpy(m_internalPose.p.data, item, sizeof(m_internalPose.p.data));
            item += sizeof(m_internalPose.p.data);
            memcpy(m_internalPose.M.data, item, sizeof(m_internalPose.M.data));
            m_poseCTs = timestamp;
            // changing the starting pose, recompute the jacobian
            updateJacobian();
        }
        return (item) ? true : false;
    }
    // in case of no cache, there is always a previous position
    return true;
}
 
bool MovingFrame::setFrame(const Frame& frame)
{
    m_internalPose = m_nextPose = frame;
    return true;
}
 
bool MovingFrame::setCallback(MovingFrameCallback _function, void* _param)
{
    m_function = _function;
    m_param = _param;
    return true;
}
 
void MovingFrame::updateCoordinates(const Timestamp& timestamp)
{
    // don't compute the velocity during substepping, it is assumed constant.
    if (!timestamp.substep) {
        bool cacheAvail = true;
        if (!timestamp.reiterate) {
            cacheAvail = popInternalFrame(timestamp.cacheTimestamp);
            if (m_function)
                (*m_function)(timestamp, m_internalPose, m_nextPose, m_param);
        }
        // only compute velocity if we have a previous pose
        if (cacheAvail && timestamp.interpolate) {
            unsigned int iXu;
            m_velocity = diff(m_internalPose, m_nextPose, timestamp.realTimestep);
            for (iXu=0; iXu<6; iXu++)
                m_xudot(iXu) = m_velocity(iXu);
        } else if (!timestamp.reiterate) {
            // new position is forced, no velocity as we cannot interpolate
            m_internalPose = m_nextPose;
            m_velocity = Twist::Zero();
            m_xudot = e_zero_vector(6);
            // recompute the jacobian
            updateJacobian();
        }
    }
}
 
void MovingFrame::pushCache(const Timestamp& timestamp)
{
    if (!timestamp.substep && timestamp.cache)
        pushInternalFrame(timestamp.cacheTimestamp);
}
 
void MovingFrame::updateKinematics(const Timestamp& timestamp)
{
    if (timestamp.interpolate) {
        if (timestamp.substep) {
            // during substepping, update the internal pose from velocity information
            Twist localvel = m_internalPose.M.Inverse(m_velocity);
            m_internalPose.Integrate(localvel, 1.0/timestamp.realTimestep);
        } else {
            m_internalPose = m_nextPose;
        }
        // m_internalPose is updated, recompute the jacobian
        updateJacobian();
    }
    pushCache(timestamp);
}
 
void MovingFrame::updateJacobian()
{
    Twist m_jac;
    e_matrix& Ju = m_JuArray[0];
 
    //Jacobian is always identity at position on the object, 
    //we ust change the reference to the world.
    //instead of going through complicated jacobian operation, implemented direct formula
    Ju(1,3) = m_internalPose.p.z();
    Ju(2,3) = -m_internalPose.p.y();
    Ju(0,4) = -m_internalPose.p.z();
    Ju(2,4) = m_internalPose.p.x();
    Ju(0,5) = m_internalPose.p.y();
    Ju(1,5) = -m_internalPose.p.x();
    // remember that this object has moved
    m_updated = true;
}
 
}