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

Example of eye-in-hand control law. We control here a real robot, the Afma6 robot (cartesian robot, with 6 degrees of freedom). The velocity is computed in the camera frame. Visual features are the two lines corresponding to the edges of a cylinder.

* 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
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* Campus Universitaire de Beaulieu
* 35042 Rennes Cedex
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* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* Description:
* tests the control law
* eye-in-hand control
* velocity computed in the camera frame
* Authors:
* Nicolas Melchior
#include <cmath> // std::fabs
#include <limits> // numeric_limits
#include <stdlib.h>
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpDebug.h> // Debug trace
#if (defined(VISP_HAVE_AFMA6) && defined(VISP_HAVE_DC1394))
#include <visp3/core/vpDisplay.h>
#include <visp3/core/vpImage.h>
#include <visp3/gui/vpDisplayGTK.h>
#include <visp3/gui/vpDisplayOpenCV.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/io/vpImageIo.h>
#include <visp3/sensor/vp1394TwoGrabber.h>
#include <visp3/core/vpCylinder.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpMath.h>
#include <visp3/me/vpMeLine.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/visual_features/vpFeatureLine.h>
#include <visp3/vs/vpServo.h>
#include <visp3/robot/vpRobotAfma6.h>
// Exception
#include <visp3/core/vpException.h>
#include <visp3/vs/vpServoDisplay.h>
int main()
try {;
#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");
vpServo task;
std::cout << std::endl;
std::cout << "-------------------------------------------------------" << std::endl;
std::cout << " Test program for vpServo " << std::endl;
std::cout << " Eye-in-hand task control, velocity computed in the camera frame" << std::endl;
std::cout << " Simulation " << std::endl;
std::cout << " task : servo a point " << std::endl;
std::cout << "-------------------------------------------------------" << std::endl;
std::cout << std::endl;
int i;
int nbline = 2;
vpMeLine line[nbline];
vpMe me;
// Initialize the tracking of the two edges of the cylinder
for (i = 0; i < nbline; i++) {
vpRobotAfma6 robot;
// robot.move("zero.pos") ;
// Update camera parameters
robot.getCameraParameters(cam, I);
vpTRACE("sets the current position of the visual feature ");
vpFeatureLine p[nbline];
for (i = 0; i < nbline; i++)
vpFeatureBuilder::create(p[i], cam, line[i]);
vpTRACE("sets the desired position of the visual feature ");
vpCylinder cyld(0, 1, 0, 0, 0, 0, 0.04);
vpHomogeneousMatrix cMo(0, 0, 0.4, 0, 0, vpMath::rad(0));
vpFeatureLine pd[nbline];
// Those lines are needed to keep the conventions define in vpMeLine
// (Those in vpLine are less restrictive) Another way to have the
// coordinates of the desired features is to learn them before executing
// the program.
pd[0].setRhoTheta(-fabs(pd[0].getRho()), 0);
pd[1].setRhoTheta(-fabs(pd[1].getRho()), M_PI);
vpTRACE("define the task");
vpTRACE("\t we want an eye-in-hand control law");
vpTRACE("\t robot is controlled in the camera frame");
vpTRACE("\t we want to see a two lines on two lines..");
std::cout << std::endl;
for (i = 0; i < nbline; i++)
task.addFeature(p[i], pd[i]);
vpTRACE("\t set the gain");
vpTRACE("Display task information ");
unsigned int iter = 0;
vpTRACE("\t loop");
double lambda_av = 0.05;
double alpha = 0.2;
double beta = 3;
for (;;) {
std::cout << "---------------------------------------------" << iter << std::endl;
try {
// Track the two edges and update the features
for (i = 0; i < nbline; i++) {
line[i].display(I, vpColor::red);
vpFeatureBuilder::create(p[i], cam, line[i]);
vpTRACE("%f %f ", line[i].getRho(), line[i].getTheta());
p[i].display(cam, I, vpColor::red);
pd[i].display(cam, I, vpColor::green);
// Adaptative gain
double gain;
if (std::fabs(alpha) <= std::numeric_limits<double>::epsilon())
gain = lambda_av;
else {
gain = alpha * exp(-beta * (task.getError()).sumSquare()) + lambda_av;
v = task.computeControlLaw();
if (iter == 0)
} catch (...) {
v = 0;
vpTRACE("\t\t || s - s* || = %f ", (task.getError()).sumSquare());
vpTRACE("Display task information ");
} 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 green
Definition: vpColor.h:220
Class that defines a 3D cylinder in the object frame and allows forward projection of a 3D cylinder i...
Definition: vpCylinder.h:103
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 flush(const vpImage< unsigned char > &I)
error that can be emited by ViSP classes.
Definition: vpException.h:72
static void create(vpFeaturePoint &s, const vpCameraParameters &cam, const vpDot &d)
Class that defines a 2D line visual feature which is composed by two parameters that are and ,...
void setRhoTheta(double rho, double theta)
void display(const vpCameraParameters &cam, const vpImage< unsigned char > &I, const vpColor &color=vpColor::green, unsigned int thickness=1) const
Implementation of an homogeneous matrix and operations on such kind of matrices.
static double rad(double deg)
Definition: vpMath.h:117
Class that tracks in an image a line moving edges.
Definition: vpMeLine.h:152
void display(const vpImage< unsigned char > &I, vpColor col)
Definition: vpMeLine.cpp:224
void track(const vpImage< unsigned char > &Im)
Definition: vpMeLine.cpp:746
void initTracking(const vpImage< unsigned char > &I)
Definition: vpMeLine.cpp:236
Definition: vpMeSite.h:74
void setDisplay(vpMeSite::vpMeSiteDisplayType select)
Definition: vpMeTracker.h:152
void setMe(vpMe *p_me)
Definition: vpMeTracker.h:173
Definition: vpMe.h:61
void setSampleStep(const double &s)
Definition: vpMe.h:278
void setRange(const unsigned int &r)
Definition: vpMe.h:271
void setPointsToTrack(const int &n)
Definition: vpMe.h:264
void setThreshold(const double &t)
Definition: vpMe.h:300
Control of Irisa's gantry robot named Afma6.
Definition: vpRobotAfma6.h:212
void setVelocity(const vpRobot::vpControlFrameType frame, const vpColVector &vel)
Definition: vpRobot.h:83
Initialize the velocity controller.
Definition: vpRobot.h:67
virtual vpRobotStateType setRobotState(const vpRobot::vpRobotStateType newState)
Definition: vpRobot.cpp:201
void setInteractionMatrixType(const vpServoIteractionMatrixType &interactionMatrixType, const vpServoInversionType &interactionMatrixInversion=PSEUDO_INVERSE)
Definition: vpServo.cpp:564
Definition: vpServo.h:155
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 setServo(const vpServoType &servo_type)
Definition: vpServo.cpp:215
vpColVector getError() const
Definition: vpServo.h:278
Definition: vpServo.h:202
vpColVector computeControlLaw()
Definition: vpServo.cpp:926
Definition: vpServo.h:186
void addFeature(vpBasicFeature &s, vpBasicFeature &s_star, unsigned int select=vpBasicFeature::FEATURE_ALL)
Definition: vpServo.cpp:487
#define vpTRACE
Definition: vpDebug.h:416