Visual Servoing Platform  version 3.6.1 under development (2024-05-21)

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. The used visual feature is a circle.

* 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/sensor/vpRealSense2.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpMath.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/visual_features/vpFeatureEllipse.h>
#include <visp3/vs/vpServo.h>
#include <visp3/robot/vpRobotAfma6.h>
// Exception
#include <visp3/core/vpException.h>
#include <visp3/vs/vpServoDisplay.h>
#include <visp3/blob/vpDot.h>
int main()
try {
vpServo task;
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");
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;
vpDot dot;
dot.setMaxDotSize(0.30); // Max dot size is 30 % of the image size
// dot.setGraphics(true) ;
std::cout << "Click on an ellipse..." << std::endl;
vpImagePoint cog = dot.getCog();
vpRobotAfma6 robot;
// Update camera parameters
robot.getCameraParameters(cam, I);
vpTRACE("sets the current position of the visual feature ");
std::cout << " Learning 0/1 " << std::endl;
int learning;
std::cin >> learning;
std::string name = "dat/ellipse.dat";
if (learning == 1) {
// save the object position
vpTRACE("Save the location of the object in a file dat/ellipse.dat");
std::ofstream f(name.c_str());
f << c.get_s().t();
vpTRACE("sets the desired position of the visual feature ");
std::ifstream f("dat/ellipse.dat");
double x, y, n20, n11, n02;
f >> x;
f >> y;
f >> n20;
f >> n11;
f >> n02;
cd.buildFrom(x, y, n20, n11, n02);
cd.setABC(0, 0, 10);
task.addFeature(c, cd);
unsigned int iter = 0;
double lambda_av = 0.01;
double alpha = 0.1; // 1 ;
double beta = 3; // 3 ;
std::cout << "alpha 0.7" << std::endl;
std::cin >> alpha;
std::cout << "beta 5" << std::endl;
std::cin >> beta;
bool quit = false;
while (!quit) {
std::cout << "---------------------------------------------" << iter++ << std::endl;
// Get the dot cog
cog = dot.getCog();
// 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;
gain = lambda_av;
vpTRACE("%f %f", (task.getError()).sumSquare(), gain);
v = task.computeControlLaw();
std::cout << "rank " << task.getTaskRank() << std::endl;
vpServoDisplay::display(task, cam, I);
std::cout << v.t();
vpDisplay::displayText(I, 20, 20, "Click to quit...", vpColor::red);
if (vpDisplay::getClick(I, false)) {
quit = true;
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:128
vpColVector get_s(unsigned int select=FEATURE_ALL) const
Get the feature vector .
Generic class defining intrinsic camera parameters.
@ perspectiveProjWithoutDistortion
Perspective projection without distortion model.
Implementation of column vector and the associated operations.
Definition: vpColVector.h:163
vpRowVector t() const
static const vpColor red
Definition: vpColor.h:211
static const vpColor blue
Definition: vpColor.h:217
static const vpColor green
Definition: vpColor.h:214
The vpDisplayGTK allows to display image using the GTK 3rd party library. Thus to enable this class G...
Definition: vpDisplayGTK.h:128
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:128
static bool getClick(const vpImage< unsigned char > &I, bool blocking=true)
static void display(const vpImage< unsigned char > &I)
static void displayCross(const vpImage< unsigned char > &I, const vpImagePoint &ip, unsigned int size, const vpColor &color, unsigned int thickness=1)
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)
This tracker is meant to track a dot (connected pixels with same gray level) on a vpImage.
Definition: vpDot.h:112
void setMaxDotSize(double percentage)
Definition: vpDot.cpp:633
void initTracking(const vpImage< unsigned char > &I)
Definition: vpDot.cpp:668
void setComputeMoments(bool activate)
Definition: vpDot.h:324
vpImagePoint getCog() const
Definition: vpDot.h:242
void track(const vpImage< unsigned char > &I)
Definition: vpDot.cpp:798
error that can be emitted by ViSP classes.
Definition: vpException.h:59
static void create(vpFeaturePoint &s, const vpCameraParameters &cam, const vpDot &d)
Class that defines 2D ellipse visual feature.
void setABC(double A, double B, double C)
void buildFrom(double x, double y, double n20, double n11, double n02)
Class that defines a 2D point in an image. This class is useful for image processing and stores only ...
Definition: vpImagePoint.h:82
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:209
void setVelocity(const vpRobot::vpControlFrameType frame, const vpColVector &vel) vp_override
Definition: vpRobot.h:82
Initialize the velocity controller.
Definition: vpRobot.h:65
virtual vpRobotStateType setRobotState(const vpRobot::vpRobotStateType newState)
Definition: vpRobot.cpp:198
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:378
Definition: vpServo.h:155
void addFeature(vpBasicFeature &s_cur, vpBasicFeature &s_star, unsigned int select=vpBasicFeature::FEATURE_ALL)
Definition: vpServo.cpp:329
unsigned int getTaskRank() const
Definition: vpServo.h:600
void print(const vpServo::vpServoPrintType display_level=ALL, std::ostream &os=std::cout)
Definition: vpServo.cpp:169
void setLambda(double c)
Definition: vpServo.h:976
void setServo(const vpServoType &servo_type)
Definition: vpServo.cpp:132
vpColVector getError() const
Definition: vpServo.h:504
Definition: vpServo.h:229
vpColVector computeControlLaw()
Definition: vpServo.cpp:703
Definition: vpServo.h:196
#define vpTRACE
Definition: vpDebug.h:407
void display(vpImage< unsigned char > &I, const std::string &title)
Display a gray-scale image.