servoViper850Point2DArtVelocity-jointAvoidance-basic.cpp

Joint limits avoidance by stopping the motion on axis near the joint limits.

Implemented from section III.B in [4].

/****************************************************************************
 *
 * This file is part of the ViSP software.
 * Copyright (C) 2005 - 2017 by Inria. All rights reserved.
 *
 * This software is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * ("GPL") version 2 as published by the Free Software Foundation.
 * See the file LICENSE.txt at the root directory of this source
 * distribution for additional information about the GNU GPL.
 *
 * For using ViSP with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * See http://visp.inria.fr for more information.
 *
 * This software was developed at:
 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 *
 * If you have questions regarding the use of this file, please contact
 * Inria at visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 *   tests the control law
 *   eye-in-hand control
 *   velocity computed in articular
 *
 * Authors:
 * Eric Marchand
 * Fabien Spindler
 *
 *****************************************************************************/

#include <visp3/core/vpConfig.h>
#include <visp3/core/vpDebug.h> // Debug trace

#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <fstream>
#include <sstream>
#include <cmath>    // std::fabs
#include <limits>   // numeric_limits

#if (defined (VISP_HAVE_VIPER850) && defined (VISP_HAVE_DC1394) && defined(VISP_HAVE_DISPLAY))

#include <visp3/sensor/vp1394TwoGrabber.h>
#include <visp3/core/vpImage.h>
#include <visp3/core/vpDisplay.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/gui/vpDisplayOpenCV.h>
#include <visp3/gui/vpDisplayGTK.h>
#include <visp3/core/vpMath.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/visual_features/vpFeaturePoint.h>
#include <visp3/core/vpPoint.h>
#include <visp3/vs/vpServo.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/robot/vpRobotViper850.h>
#include <visp3/core/vpIoTools.h>
#include <visp3/core/vpException.h>
#include <visp3/vs/vpServoDisplay.h>
#include <visp3/blob/vpDot2.h>
#include <visp3/gui/vpPlot.h>


int
main()
{
  try {
    vpRobotViper850 robot ;

    vpServo task ;

    vpImage<unsigned char> I ;

    bool reset = false;
    vp1394TwoGrabber g(reset);
    g.setVideoMode(vp1394TwoGrabber::vpVIDEO_MODE_640x480_MONO8);
    g.setFramerate(vp1394TwoGrabber::vpFRAMERATE_60);
    g.open(I) ;

    g.acquire(I) ;

    double Tloop = 1./60.f;

    vp1394TwoGrabber::vp1394TwoFramerateType fps;
    g.getFramerate(fps);
    switch(fps) {
    case vp1394TwoGrabber::vpFRAMERATE_15 : Tloop = 1.f/15.f; break;
    case vp1394TwoGrabber::vpFRAMERATE_30 : Tloop = 1.f/30.f; break;
    case vp1394TwoGrabber::vpFRAMERATE_60 : Tloop = 1.f/60.f; break;
    case vp1394TwoGrabber::vpFRAMERATE_120: Tloop = 1.f/120.f; break;
    default: break;
    }
    std::cout << "Tloop: " << Tloop << std::endl; 

#ifdef VISP_HAVE_X11
    vpDisplayX display(I,800,100,"Current image") ;
#elif defined(VISP_HAVE_OPENCV)
    vpDisplayOpenCV display(I,800,100,"Current image") ;
#elif defined(VISP_HAVE_GTK)
    vpDisplayGTK display(I,800,100,"Current image") ;
#endif

    vpDisplay::display(I) ;
    vpDisplay::flush(I) ;

    vpColVector jointMin(6), jointMax(6) ;
    jointMin = robot.getJointMin();
    jointMax = robot.getJointMax();

    vpColVector Qmin(6), tQmin(6) ;
    vpColVector Qmax(6), tQmax(6) ;
    vpColVector Qmiddle(6);
    vpColVector data(10) ;

    double rho = 0.25 ;
    for (unsigned int i=0 ; i < 6 ; i++)
    {
      Qmin[i] = jointMin[i] + 0.5*rho*(jointMax[i]-jointMin[i]) ;
      Qmax[i] = jointMax[i] - 0.5*rho*(jointMax[i]-jointMin[i]) ;
    }
    Qmiddle = (Qmin + Qmax) /2.;
    double rho1 = 0.1 ;
    
    for (unsigned int i=0 ; i < 6 ; i++) {
      tQmin[i]=Qmin[i]+ 0.5*(rho1)*(Qmax[i]-Qmin[i]) ;
      tQmax[i]=Qmax[i]- 0.5*(rho1)*(Qmax[i]-Qmin[i]) ;
    }

    vpColVector q(6) ;

    // Create a window with two graphics
    // - first graphic to plot q(t), Qmin, Qmax, tQmin and tQmax
    // - second graphic to plot the cost function h_s
    vpPlot plot(2);

    // The first graphic contains 10 data to plot: q(t), Qmin, Qmax, tQmin and
    // tQmax
    plot.initGraph(0, 10);
    plot.initGraph(1, 6);

    // For the first graphic :
    // - along the x axis the expected values are between 0 and 200 and 
    //   the step is 1 
    // - along the y axis the expected values are between -1.2 and 1.2 and the
    //   step is 0.1
    plot.initRange(0,0,200,1,-1.2,1.2,0.1);
    plot.setTitle(0, "Joint behavior");
    plot.initRange(1,0,200,1,-0.01,0.01,0.05);
    plot.setTitle(1, "Joint velocity");

    // For the first graphic, set the curves legend
    char legend[10];
    for (unsigned int i=0; i < 6; i++) {
      sprintf(legend, "q%u", i+1);
      plot.setLegend(0, i, legend); 
      sprintf(legend, "q%u", i+1);
      plot.setLegend(1, i, legend);
    }
    plot.setLegend(0, 6, "tQmin");
    plot.setLegend(0, 7, "tQmax");
    plot.setLegend(0, 8, "Qmin");
    plot.setLegend(0, 9, "Qmax");

    // Set the curves color
    plot.setColor(0, 0, vpColor::red); 
    plot.setColor(0, 1, vpColor::green); 
    plot.setColor(0, 2, vpColor::blue); 
    plot.setColor(0, 3, vpColor::orange); 
    plot.setColor(0, 4, vpColor(0, 128, 0)); 
    plot.setColor(0, 5, vpColor::cyan); 
    for (unsigned int i= 6; i < 10; i++)
      plot.setColor(0, i, vpColor::black); // for Q and tQ [min,max]
    // Set the curves color

    plot.setColor(1, 0, vpColor::red); 
    plot.setColor(1, 1, vpColor::green); 
    plot.setColor(1, 2, vpColor::blue); 
    plot.setColor(1, 3, vpColor::orange); 
    plot.setColor(1, 4, vpColor(0, 128, 0)); 
    plot.setColor(1, 5, vpColor::cyan); 
    vpDot2 dot ;
    

    std::cout << "Click on a dot..." << std::endl;
    dot.initTracking(I) ;
    vpImagePoint cog = dot.getCog();
    vpDisplay::displayCross(I, cog, 10, vpColor::blue) ;
    vpDisplay::flush(I);

    vpCameraParameters cam ;
    // Update camera parameters
    robot.getCameraParameters (cam, I);

    // sets the current position of the visual feature
    vpFeaturePoint p ;
    vpFeatureBuilder::create(p,cam, dot)  ;  //retrieve x,y and Z of the vpPoint structure

    p.set_Z(1) ;
    // sets the desired position of the visual feature
    vpFeaturePoint pd ;
    pd.buildFrom(0,0,1) ;

    // Define the task
    // - we want an eye-in-hand control law
    // - articular velocity are computed
    task.setServo(vpServo::EYEINHAND_L_cVe_eJe) ;
    task.setInteractionMatrixType(vpServo::DESIRED, vpServo::PSEUDO_INVERSE) ;

    vpVelocityTwistMatrix cVe ;
    robot.get_cVe(cVe) ;
    std::cout << cVe <<std::endl ;
    task.set_cVe(cVe) ;

    // - Set the Jacobian (expressed in the end-effector frame)") ;
    vpMatrix eJe ;
    robot.get_eJe(eJe) ;
    task.set_eJe(eJe) ;

    // - we want to see a point on a point..") ;
    std::cout << std::endl ;
    task.addFeature(p,pd) ;

    // - set the gain
    double lambda = 0.8;
    // set to -1 to suppress the lambda used in the vpServo::computeControlLaw()
    task.setLambda(-1) ; 

    // Display task information " ) ;
    task.print() ;

    robot.setRobotState(vpRobot::STATE_VELOCITY_CONTROL) ;

    int iter = 0;
    double t_1 = vpTime::measureTimeMs();

    std::cout << "\nHit CTRL-C to stop the loop...\n" << std::flush;
    for ( ; ; ) {
      iter ++;
      
      double t_0 = vpTime::measureTimeMs(); // t_0: current time

      // Update loop time in second
      double Tv = (double)(t_0 - t_1) / 1000.0;
      std::cout << "Tv: " << Tv << std::endl;
      
      // Update time for next iteration
      t_1 = t_0;
      
      // Acquire a new image from the camera
      dc1394video_frame_t *frame = g.dequeue(I);

      // Display this image
      vpDisplay::display(I) ;

      // Achieve the tracking of the dot in the image
      dot.track(I) ;
      cog = dot.getCog();

      // Display a green cross at the center of gravity position in the image
      vpDisplay::displayCross(I, cog, 10, vpColor::green) ;

      // Get the measured joint positions of the robot
      robot.getPosition(vpRobot::ARTICULAR_FRAME, q);

      // Update the point feature from the dot location
      vpFeatureBuilder::create(p, cam, dot);

      // Get the jacobian of the robot
      robot.get_eJe(eJe) ;
      // Update this jacobian in the task structure. It will be used to compute
      // the velocity skew (as an articular velocity)
      // qdot = -lambda * L^+ * cVe * eJe * (s-s*)
      task.set_eJe(eJe) ;

      vpColVector prim_task ;
      vpColVector e2(6) ;
      // Compute the visual servoing skew vector
      prim_task = task.computeControlLaw() ;

      vpColVector qpre(6);

      qpre = q ;
      qpre += -lambda*prim_task*(4*Tloop)  ;

      // Identify the joints near the limits
      vpColVector pb(6) ; pb = 0 ;
      unsigned int npb =0 ;
      for (unsigned int i=0 ; i < 6 ;i++) {
        if (q[i] < tQmin[i])
          if (fabs(Qmin[i]-q[i]) > fabs(Qmin[i]-qpre[i])) {
            pb[i] = 1 ; npb++ ;
            std::cout << "Joint " << i << " near limit " << std::endl ;
          }
        if (q[i]>tQmax[i]) {
          if (fabs(Qmax[i]-q[i]) > fabs(Qmax[i]-qpre[i])) {
            pb[i] = 1 ; npb++ ;
            std::cout << "Joint " << i << " near limit " << std::endl ;
          }
        }
      }

      vpColVector a0 ;
      vpMatrix J1 = task.getTaskJacobian();
      vpMatrix kernelJ1;
      J1.kernel(kernelJ1);

      unsigned int dimKernelL = kernelJ1.getCols() ;
      if (npb != 0) {
        // Build linear system a0*E = S
        vpMatrix E(npb, dimKernelL) ;
        vpColVector S(npb) ;

        unsigned int k=0 ;

        for (unsigned int j=0 ; j < 6 ; j++) // j is the joint
          //if (pb[j]==1)   {
          if (std::fabs(pb[j]-1) <= std::numeric_limits<double>::epsilon()) {
            for (unsigned int i=0 ; i < dimKernelL ; i++)
              E[k][i] = kernelJ1[j][i] ;

            S[k] = -prim_task[j]  ;
            k++ ;
          }
        vpMatrix Ep ;
        //vpTRACE("nbp %d", npb);
        Ep = E.t()*(E*E.t()).pseudoInverse() ;
        a0 = Ep*S ;

        e2 = (kernelJ1*a0) ;
        //cout << "e2 " << e2.t() ;
      }
      else {
        e2 = 0;
      }
      //  std::cout << "e2: " << e2.t() << std::endl; 

      vpColVector v ;
      v = -lambda * (prim_task + e2);

      // Display the current and desired feature points in the image display
      vpServoDisplay::display(task, cam, I) ;

      // Apply the computed joint velocities to the robot
      robot.setVelocity(vpRobot::ARTICULAR_FRAME, v) ;

      {
        // Add the material to plot curves

        // q normalized between (entre -1 et 1)
        for (unsigned int i=0 ; i < 6 ; i++) {
          data[i] = (q[i] - Qmiddle[i]) ;
          data[i] /= (Qmax[i] - Qmin[i]) ;
          data[i]*=2 ;
        }
        unsigned int joint = 2;
        data[6] = 2*(tQmin[joint]-Qmiddle[joint])/(Qmax[joint] - Qmin[joint]) ;
        data[7] = 2*(tQmax[joint]-Qmiddle[joint])/(Qmax[joint] - Qmin[joint]) ;
        data[8] = -1 ; data[9] = 1 ;

        plot.plot(0, iter, data); // plot q, Qmin, Qmax, tQmin, tQmax
        plot.plot(1, iter, v); // plot joint velocities applied to the robot
      }

      vpDisplay::flush(I) ;

      // Synchronize the loop with the image frame rate
      vpTime::wait(t_0, 1000.*Tloop);
      // Release the ring buffer used for the last image to start a new acq
      g.enqueue(frame);
    }

    // Display task information
    task.print() ;
    task.kill();
    return 0;
  }
  catch (...)
  {
    vpERROR_TRACE(" Test failed") ;
    return 0;
  }
}


#else
int
main()
{
  vpERROR_TRACE("You do not have an afma6 robot or a firewire framegrabber connected to your computer...");
}
#endif