manServoMomentsSimple.cpp

Minimalist example of moment-based visual servoing with polygon and a simple robot

/****************************************************************************
 *
 * This file is part of the ViSP software.
 * Copyright (C) 2005 - 2015 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:
 * Example of visual servoing with moments using a polygon as object container
 *
 * Authors:
 * Filip Novotny
 *
 *****************************************************************************/

#include <visp3/core/vpPoint.h> //the basic tracker

#include <vector> //store the polygon
#include <visp3/core/vpMomentObject.h> //transmit the polygon to the object
#include <visp3/core/vpMomentCommon.h> //update the common database with the object
#include <visp3/visual_features/vpFeatureMomentCommon.h> //init the feature database using the information about moment dependencies
#include <visp3/vs/vpServo.h> //visual servoing task
#include <visp3/robot/vpSimulatorCamera.h>
#include <visp3/core/vpPlane.h>
#include <visp3/core/vpException.h>
#include <limits>
#include <iostream> //some console output
//this function converts the plane defined by the cMo to 1/Z=Ax+By+C plane form

void cMoToABC(vpHomogeneousMatrix& cMo, double& A,double& B, double& C);

void cMoToABC(vpHomogeneousMatrix& cMo, double& A,double& B, double& C)
{
    vpPlane pl;
    pl.setABCD(0,0,1.0,0);
  pl.changeFrame(cMo);

    if(fabs(pl.getD())<std::numeric_limits<double>::epsilon()){
        std::cout << "Invalid position:" << std::endl;
        std::cout << cMo << std::endl;
        std::cout << "Cannot put plane in the form 1/Z=Ax+By+C." << std::endl;
        throw vpException(vpException::divideByZeroError,"invalid position!");
    }
  A=-pl.getA()/pl.getD();
  B=-pl.getB()/pl.getD();
  C=-pl.getC()/pl.getD();
}

int main()
{
  try {
    double x[8] = { 1,3, 4,-1 ,-3,-2,-1,1};
    double y[8] = { 0,1, 4, 4, -2,-2, 1,0};
    double A,B,C,Ad,Bd,Cd;

    int nbpoints = 8;
    std::vector<vpPoint> vec_p,vec_p_d; // vectors that contain the vertices of the contour polygon

    vpHomogeneousMatrix cMo(0.1,0.0,1.0,vpMath::rad(0),vpMath::rad(0),vpMath::rad(0));
    vpHomogeneousMatrix cdMo(vpHomogeneousMatrix(0.0,0.0,1.0,vpMath::rad(0),vpMath::rad(0),-vpMath::rad(0)));
    vpHomogeneousMatrix wMo; // Set to identity
    vpHomogeneousMatrix wMc; // Camera position in the world frame

    cMoToABC(cMo,A,B,C);
    cMoToABC(cdMo,Ad,Bd,Cd);
    // Define source and destination polygons
    for (int i = 0 ; i < nbpoints ; i++){
      vpPoint p(x[i],y[i],0.0);
      p.track(cMo);
      vec_p.push_back(p);
      p.track(cdMo) ;
      vec_p_d.push_back(p);
    }

    vpMomentObject cur(6); // Create a source moment object with 6 as maximum order
    cur.setType(vpMomentObject::DENSE_POLYGON); // The object is defined by a countour polygon
    cur.fromVector(vec_p); // Init the dense object with the source polygon

    vpMomentObject dst(6); // Create a destination moment object with 6 as maximum order
    dst.setType(vpMomentObject::DENSE_POLYGON); // The object is defined by a countour polygon
    dst.fromVector(vec_p_d); // Init the dense object with the destination polygon

    //init classic moment primitives (for source)
    vpMomentCommon mdb_cur(vpMomentCommon::getSurface(dst),vpMomentCommon::getMu3(dst),vpMomentCommon::getAlpha(dst)); //Init classic features
    vpFeatureMomentCommon fmdb_cur(mdb_cur);

    vpMomentCommon mdb_dst(vpMomentCommon::getSurface(dst),vpMomentCommon::getMu3(dst),vpMomentCommon::getAlpha(dst)); //Init classic features
    vpFeatureMomentCommon fmdb_dst(mdb_dst);

    //update+compute moment primitives from object (for destination)
    mdb_dst.updateAll(dst);
    //update+compute features (+interaction matrixes) from plane
    fmdb_dst.updateAll(Ad,Bd,Cd);

    //define visual servoing task
    vpServo task;
    task.setServo(vpServo::EYEINHAND_CAMERA);
    task.setInteractionMatrixType(vpServo::CURRENT);
    task.setLambda(1) ;

    task.addFeature(fmdb_cur.getFeatureGravityNormalized(),fmdb_dst.getFeatureGravityNormalized());
    task.addFeature(fmdb_cur.getFeatureAn(),fmdb_dst.getFeatureAn());
    //the object is NOT symmetric
    //select C4 and C6
    task.addFeature(fmdb_cur.getFeatureCInvariant(),fmdb_dst.getFeatureCInvariant(),
                    vpFeatureMomentCInvariant::selectC4() | vpFeatureMomentCInvariant::selectC6());
    task.addFeature(fmdb_cur.getFeatureAlpha(),fmdb_dst.getFeatureAlpha());

    vpBasicFeature *al = new vpFeatureMomentAlpha(mdb_dst,0,0,1.);
    al->init();
    al->error(*al);
    //param robot
    vpSimulatorCamera robot ;
    float sampling_time = 0.010f; // Sampling period in seconds
    robot.setSamplingTime(sampling_time);
    wMc = wMo * cMo.inverse();
    robot.setPosition(wMc);

    do{
      wMc = robot.getPosition();
      cMo = wMc.inverse() * wMo;
      vec_p.clear();

      for (int i = 0 ; i < nbpoints ; i++){
        vpPoint p(x[i],y[i],0.0);
        p.track(cMo) ;
        vec_p.push_back(p);
      }
      cMoToABC(cMo,A,B,C);

      cur.fromVector(vec_p);
      //update+compute moment primitives from object (for source)
      mdb_cur.updateAll(cur);
      //update+compute features (+interaction matrixes) from plane
      fmdb_cur.updateAll(A,B,C);

      vpColVector v = task.computeControlLaw();
      task.print();
      robot.setVelocity(vpRobot::CAMERA_FRAME, v) ;
      double t = vpTime::measureTimeMs();
      vpTime::wait(t, sampling_time * 1000); // Wait 10 ms
    } while(( task.getError() ).sumSquare()>0.005);
    std::cout << "final error=" << ( task.getError() ).sumSquare() << std::endl;
    return 0;
  }
  catch(vpException e) {
    std::cout << "Catch an exception: " << e << std::endl;
    return 1;
  }
}