Visual Servoing Platform  version 3.6.1 under development (2024-07-15)

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.

* ViSP, open source Visual Servoing Platform software.
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* Description:
* tests the control law
* eye-in-hand control
* velocity computed in the camera frame
#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/vpRealSense2.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpLine.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()
using namespace VISP_NAMESPACE_NAME;
try {
rs2::config config;
config.enable_stream(RS2_STREAM_COLOR, 640, 480, RS2_FORMAT_RGBA8, 30);
config.enable_stream(RS2_STREAM_DEPTH, 640, 480, RS2_FORMAT_Z16, 30);
config.enable_stream(RS2_STREAM_INFRARED, 640, 480, RS2_FORMAT_Y8, 30);;
// Warm up camera
for (size_t i = 0; i < 10; ++i) {
#ifdef VISP_HAVE_X11
vpDisplayX display(I, 100, 100, "Current image");
#elif defined(HAVE_OPENCV_HIGHGUI)
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. Define the two lines to track
vpTRACE("The two lines to track must be parallels ");
// vpTRACE("The two lines to track must be perpendicular ") ;
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 ");
vpLine lined[2];
lined[0].setWorldCoordinates(1, 0, 0, -0.05, 0, 0, 1, 0);
lined[1].setWorldCoordinates(1, 0, 0, 0.05, 0, 0, 1, 0);
vpHomogeneousMatrix cMo(0, 0, 0.5, 0, 0, vpMath::rad(0));
// 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.
vpFeatureLine pd[nbline];
vpFeatureBuilder::create(pd[0], lined[0]);
vpFeatureBuilder::create(pd[1], lined[1]);
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 point on a point..");
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;
bool quit = false;
while (!quit) {
std::cout << "---------------------------------------------" << iter << std::endl;
try {
// Track the lines and update the features
for (i = 0; i < nbline; i++) {
line[i].display(I, vpColor::red);
vpFeatureBuilder::create(p[i], cam, line[i]);
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) {
vpDisplay::displayText(I, 20, 20, "Click to quit...", vpColor::red);
if (vpDisplay::getClick(I, false)) {
quit = true;
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;
Definition: vpAfma6.h:131
Generic class defining intrinsic camera parameters.
@ perspectiveProjWithoutDistortion
Perspective projection without distortion model.
Implementation of column vector and the associated operations.
Definition: vpColVector.h:191
static const vpColor red
Definition: vpColor.h:217
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:133
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)
static void displayText(const vpImage< unsigned char > &I, const vpImagePoint &ip, const std::string &s, const vpColor &color)
error that can be emitted by ViSP classes.
Definition: vpException.h:60
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 display(const vpCameraParameters &cam, const vpImage< unsigned char > &I, const vpColor &color=vpColor::green, unsigned int thickness=1) const VP_OVERRIDE
Implementation of an homogeneous matrix and operations on such kind of matrices.
Class that defines a 3D line in the object frame and allows forward projection of the line in the cam...
Definition: vpLine.h:103
void setRho(double rho)
Definition: vpLine.h:153
void setTheta(double theta)
Definition: vpLine.h:163
void setWorldCoordinates(const double &oA1, const double &oB1, const double &oC1, const double &oD1, const double &oA2, const double &oB2, const double &oC2, const double &oD2)
Definition: vpLine.cpp:83
static double rad(double deg)
Definition: vpMath.h:129
Class that tracks in an image a line moving edges.
Definition: vpMeLine.h:152
void display(const vpImage< unsigned char > &I, const vpColor &color, unsigned int thickness=1)
Definition: vpMeLine.cpp:194
void track(const vpImage< unsigned char > &I)
Definition: vpMeLine.cpp:664
void initTracking(const vpImage< unsigned char > &I)
Definition: vpMeLine.cpp:199
Definition: vpMeSite.h:78
void setDisplay(vpMeSite::vpMeSiteDisplayType select)
Definition: vpMeTracker.h:232
void setMe(vpMe *me)
Definition: vpMeTracker.h:260
Definition: vpMe.h:134
void setPointsToTrack(const int &points_to_track)
Definition: vpMe.h:408
void setRange(const unsigned int &range)
Definition: vpMe.h:415
void setLikelihoodThresholdType(const vpLikelihoodThresholdType likelihood_threshold_type)
Definition: vpMe.h:505
void setThreshold(const double &threshold)
Definition: vpMe.h:466
void setSampleStep(const double &sample_step)
Definition: vpMe.h:422
Definition: vpMe.h:145
void acquire(vpImage< unsigned char > &grey, double *ts=nullptr)
bool open(const rs2::config &cfg=rs2::config())
Control of Irisa's gantry robot named Afma6.
Definition: vpRobotAfma6.h:212
void setVelocity(const vpRobot::vpControlFrameType frame, const vpColVector &vel) VP_OVERRIDE
Definition: vpRobot.h:84
Initialize the velocity controller.
Definition: vpRobot.h:67
virtual vpRobotStateType setRobotState(const vpRobot::vpRobotStateType newState)
Definition: vpRobot.cpp:202
Definition: vpServo.h:161
void addFeature(vpBasicFeature &s_cur, vpBasicFeature &s_star, unsigned int select=vpBasicFeature::FEATURE_ALL)
Definition: vpServo.cpp:331
void print(const vpServo::vpServoPrintType display_level=ALL, std::ostream &os=std::cout)
Definition: vpServo.cpp:171
void setLambda(double c)
Definition: vpServo.h:986
void setServo(const vpServoType &servo_type)
Definition: vpServo.cpp:134
vpColVector getError() const
Definition: vpServo.h:510
vpColVector computeControlLaw()
Definition: vpServo.cpp:705
#define vpTRACE
Definition: vpDebug.h:436