Visual Servoing Platform  version 3.5.1 under development (2022-07-07)

Example of a eye-to-hand control law. We control here a real robot, the Afma6 robot (cartesian robot, with 6 degrees of freedom). The robot is controlled in the camera frame.

* ViSP, open source Visual Servoing Platform software.
* Copyright (C) 2005 - 2019 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 as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* See the file LICENSE.txt at the root directory of this source
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* Edition License.
* See 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
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* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* Description:
* tests the control law
* eye-to-hand control
* velocity computed in the camera frame
* Authors:
* Eric Marchand
#include <cmath> // std::fabs
#include <limits> // numeric_limits
#include <list>
#include <stdlib.h>
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpDebug.h> // Debug trace
#if (defined(VISP_HAVE_AFMA6) && defined(VISP_HAVE_DC1394))
#define SAVE 0
#include <visp3/blob/vpDot.h>
#include <visp3/core/vpDisplay.h>
#include <visp3/core/vpException.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpImage.h>
#include <visp3/core/vpImagePoint.h>
#include <visp3/core/vpMath.h>
#include <visp3/core/vpPoint.h>
#include <visp3/gui/vpDisplayGTK.h>
#include <visp3/gui/vpDisplayOpenCV.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/io/vpImageIo.h>
#include <visp3/robot/vpRobotAfma6.h>
#include <visp3/sensor/vp1394TwoGrabber.h>
#include <visp3/vision/vpPose.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/visual_features/vpFeaturePoint.h>
#include <visp3/vs/vpServo.h>
#include <visp3/vs/vpServoDisplay.h>
#define L 0.006
#define D 0
int main()
try {
vpServo task;
int i;;
#ifdef VISP_HAVE_X11
vpDisplayX display(I, 100, 100, "Current image");
#elif defined(VISP_HAVE_OPENCV)
vpDisplayOpenCV display(I, 100, 100, "Current image");
#elif defined(VISP_HAVE_GTK)
vpDisplayGTK display(I, 100, 100, "Current image");
std::cout << std::endl;
std::cout << "-------------------------------------------------------" << std::endl;
std::cout << " Test program for vpServo " << std::endl;
std::cout << " Eye-to-hand task control" << std::endl;
std::cout << " Simulation " << std::endl;
std::cout << " task : servo a point " << std::endl;
std::cout << "-------------------------------------------------------" << std::endl;
std::cout << std::endl;
int nbPoint = 7;
vpDot dot[nbPoint];
for (i = 0; i < nbPoint; i++) {
// Compute the pose 3D model
vpPoint point[nbPoint];
point[0].setWorldCoordinates(-2 * L, D, -3 * L);
point[1].setWorldCoordinates(0, D, -3 * L);
point[2].setWorldCoordinates(2 * L, D, -3 * L);
point[3].setWorldCoordinates(-L, D, -L);
point[4].setWorldCoordinates(L, D, -L);
point[5].setWorldCoordinates(L, D, L);
point[6].setWorldCoordinates(-L, D, L);
vpRobotAfma6 robot;
// Update camera parameters
robot.getCameraParameters(cam, I);
vpPose pose;
for (i = 0; i < nbPoint; i++) {
cog = dot[i].getCog();
double x = 0, y = 0;
// compute the initial pose using Dementhon method followed by a non
// linear minimisation method
std::cout << cMo << std::endl;
-- Learning the desired position
-- or reading the desired position
std::cout << " Learning 0/1 " << std::endl;
char name[FILENAME_MAX];
sprintf(name, "cdMo.dat");
int learning;
std::cin >> learning;
if (learning == 1) {
// save the object position
vpTRACE("Save the location of the object in a file cdMo.dat");
std::ofstream f(name);;
vpTRACE("Loading desired location from cdMo.dat");
std::ifstream f("cdMo.dat");
vpFeaturePoint p[nbPoint], pd[nbPoint];
// set the desired position of the point by forward projection using
// the pose cdMo
for (i = 0; i < nbPoint; i++) {
vpColVector cP, p;
point[i].changeFrame(cdMo, cP);
point[i].projection(cP, p);
vpTRACE("define the task");
vpTRACE("\t we want an eye-in-hand control law");
vpTRACE("\t robot is controlled in the camera frame");
for (i = 0; i < nbPoint; i++) {
task.addFeature(p[i], pd[i]);
vpTRACE("Display task information ");
double convergence_threshold = 0.00; // 025 ;
double error = 1;
unsigned int iter = 0;
vpTRACE("\t loop");
vpColVector v; // computed robot velocity
// position of the object in the effector frame
vpHomogeneousMatrix oMcamrobot;
oMcamrobot[0][3] = -0.05;
int it = 0;
double lambda_av = 0.1;
double alpha = 1; // 1 ;
double beta = 3; // 3 ;
std::cout << "alpha 0.7" << std::endl;
std::cin >> alpha;
std::cout << "beta 5" << std::endl;
std::cin >> beta;
std::list<vpImagePoint> Lcog;
while (error > convergence_threshold) {
std::cout << "---------------------------------------------" << iter++ << std::endl;
vpDisplay::displayText(I, ip, "Eye-To-Hand Visual Servoing", vpColor::green);
vpDisplay::displayText(I, ip, "IRISA-INRIA Rennes, Lagadic project", vpColor::green);
try {
for (i = 0; i < nbPoint; i++) {
} catch (...) {
vpTRACE("Error detected while tracking visual features");
// compute the initial pose using a non linear minimisation method
for (i = 0; i < nbPoint; i++) {
double x = 0, y = 0;
cog = dot[i].getCog();
point[i].changeFrame(cdMo, cP);
point[i].display(I, cMo, cam, vpColor::green);
point[i].display(I, cdMo, cam, vpColor::blue);
vpHomogeneousMatrix cMe, camrobotMe;
cMe = cMo * oMcamrobot * camrobotMe;
vpMatrix eJe;
// Compute the adaptative gain (speed up the convergence)
double gain;
if (iter > 2) {
if (std::fabs(alpha) <= std::numeric_limits<double>::epsilon())
gain = lambda_av;
else {
gain = alpha * exp(-beta * (task.getError()).sumSquare()) + lambda_av;
} else
gain = lambda_av;
if (SAVE == 1)
gain = gain / 5;
vpTRACE("%f %f %f %f %f", alpha, beta, lambda_av, (task.getError()).sumSquare(), gain);
v = task.computeControlLaw();
// display points trajectory
for (std::list<vpImagePoint>::const_iterator it_cog = Lcog.begin(); it_cog != Lcog.end(); ++it_cog) {
vpServoDisplay::display(task, cam, I);
error = (task.getError()).sumSquare();
std::cout << "|| s - s* || = " << error << std::endl;
if (error > 7) {
vpTRACE("Error detected while tracking visual features");
// display the pose
// pose.display(I,cMo,cam, 0.04, vpColor::red) ;
// display the pose
// pose.display(I,cdMo,cam, 0.04, vpColor::blue) ;
if ((SAVE == 1) && (iter % 3 == 0)) {
sprintf(name, "/tmp/marchand/image.%04d.ppm", it++);
vpImageIo::write(Ic, name);
v = 0;
} catch (const vpException &e) {
std::cout << "Test failed with exception: " << e << std::endl;
int main()
std::cout << "You do not have an afma6 robot connected to your computer..." << std::endl;
Class for firewire ieee1394 video devices using libdc1394-2.x api.
void acquire(vpImage< unsigned char > &I)
void setVideoMode(vp1394TwoVideoModeType videomode)
void setFramerate(vp1394TwoFramerateType fps)
void open(vpImage< unsigned char > &I)
Generic class defining intrinsic camera parameters.
Implementation of column vector and the associated operations.
Definition: vpColVector.h:131
static const vpColor red
Definition: vpColor.h:217
static const vpColor blue
Definition: vpColor.h:223
static const vpColor green
Definition: vpColor.h:220
The vpDisplayGTK allows to display image using the GTK 3rd party library. Thus to enable this class G...
Definition: vpDisplayGTK.h:135
The vpDisplayOpenCV allows to display image using the OpenCV library. Thus to enable this class OpenC...
Use the X11 console to display images on unix-like OS. Thus to enable this class X11 should be instal...
Definition: vpDisplayX.h:135
static bool getClick(const vpImage< unsigned char > &I, bool blocking=true)
static void display(const vpImage< unsigned char > &I)
static void getImage(const vpImage< unsigned char > &Is, vpImage< vpRGBa > &Id)
Definition: vpDisplay.cpp:144
static void flush(const vpImage< unsigned char > &I)
static void displayPoint(const vpImage< unsigned char > &I, const vpImagePoint &ip, const vpColor &color, unsigned int thickness=1)
static void displayText(const vpImage< unsigned char > &I, const vpImagePoint &ip, const std::string &s, const vpColor &color)
This tracker is meant to track a dot (connected pixels with same gray level) on a vpImage.
Definition: vpDot.h:116
void initTracking(const vpImage< unsigned char > &I)
Definition: vpDot.cpp:635
void setGraphics(bool activate)
Definition: vpDot.h:361
vpImagePoint getCog() const
Definition: vpDot.h:247
void track(const vpImage< unsigned char > &I)
Definition: vpDot.cpp:770
error that can be emited by ViSP classes.
Definition: vpException.h:72
Class that defines a 2D point visual feature which is composed by two parameters that are the cartes...
void set_y(double y)
void set_x(double x)
void set_Z(double Z)
Implementation of an homogeneous matrix and operations on such kind of matrices.
void load(std::ifstream &f)
void print() const
Print the matrix as a pose vector .
void save(std::ofstream &f) const
static void write(const vpImage< unsigned char > &I, const std::string &filename, int backend=IO_DEFAULT_BACKEND)
Definition: vpImageIo.cpp:292
Class that defines a 2D point in an image. This class is useful for image processing and stores only ...
Definition: vpImagePoint.h:89
void set_j(double jj)
Definition: vpImagePoint.h:309
void set_i(double ii)
Definition: vpImagePoint.h:298
Implementation of a matrix and operations on matrices.
Definition: vpMatrix.h:154
static void convertPoint(const vpCameraParameters &cam, const double &u, const double &v, double &x, double &y)
Class that defines a 3D point in the object frame and allows forward projection of a 3D point in the ...
Definition: vpPoint.h:82
void set_x(double x)
Set the point x coordinate in the image plane.
Definition: vpPoint.cpp:511
void projection(const vpColVector &_cP, vpColVector &_p) const
Definition: vpPoint.cpp:222
void display(const vpImage< unsigned char > &I, const vpCameraParameters &cam, const vpColor &color=vpColor::green, unsigned int thickness=1)
Definition: vpPoint.cpp:430
void changeFrame(const vpHomogeneousMatrix &cMo, vpColVector &cP) const
Definition: vpPoint.cpp:239
void setWorldCoordinates(double oX, double oY, double oZ)
Definition: vpPoint.cpp:113
void set_y(double y)
Set the point y coordinate in the image plane.
Definition: vpPoint.cpp:513
Class used for pose computation from N points (pose from point only). Some of the algorithms implemen...
Definition: vpPose.h:90
void addPoint(const vpPoint &P)
Definition: vpPose.cpp:148
Definition: vpPose.h:102
Definition: vpPose.h:96
void clearPoint()
Definition: vpPose.cpp:133
bool computePose(vpPoseMethodType method, vpHomogeneousMatrix &cMo, bool(*func)(const vpHomogeneousMatrix &)=NULL)
Definition: vpPose.cpp:373
Control of Irisa's gantry robot named Afma6.
Definition: vpRobotAfma6.h:212
void setVelocity(const vpRobot::vpControlFrameType frame, const vpColVector &vel)
void get_eJe(vpMatrix &eJe)
Definition: vpRobot.h:79
Definition: vpRobot.h:83
Initialize the velocity controller.
Definition: vpRobot.h:67
virtual vpRobotStateType setRobotState(const vpRobot::vpRobotStateType newState)
Definition: vpRobot.cpp:201
static void display(const vpServo &s, const vpCameraParameters &cam, const vpImage< unsigned char > &I, vpColor currentColor=vpColor::green, vpColor desiredColor=vpColor::red, unsigned int thickness=1)
void setInteractionMatrixType(const vpServoIteractionMatrixType &interactionMatrixType, const vpServoInversionType &interactionMatrixInversion=PSEUDO_INVERSE)
Definition: vpServo.cpp:564
Definition: vpServo.h:164
void set_cVe(const vpVelocityTwistMatrix &cVe_)
Definition: vpServo.h:448
void print(const vpServo::vpServoPrintType display_level=ALL, std::ostream &os=std::cout)
Definition: vpServo.cpp:303
void setLambda(double c)
Definition: vpServo.h:404
void set_eJe(const vpMatrix &eJe_)
Definition: vpServo.h:506
void setServo(const vpServoType &servo_type)
Definition: vpServo.cpp:215
vpColVector getError() const
Definition: vpServo.h:278
vpColVector computeControlLaw()
Definition: vpServo.cpp:926
Definition: vpServo.h:182
void addFeature(vpBasicFeature &s, vpBasicFeature &s_star, unsigned int select=vpBasicFeature::FEATURE_ALL)
Definition: vpServo.cpp:487
vpHomogeneousMatrix get_cMe() const
Definition: vpUnicycle.h:74
#define vpTRACE
Definition: vpDebug.h:416