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

Servo a point:

wrt. servoSimuPoint2DCamVelocity1.cpp only the type of control law is modified. This illustrates the need for Jacobian update and Twist transformation matrix initialization, only the X coordinate is selected.

Only the X coordinate is selected (test the selection process).

* 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
* distribution for additional information about the GNU GPL.
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* Edition License.
* See for more information.
* This software was developed at:
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* 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:
* Simulation of a 2D visual servoing on a point.
* Authors:
* Eric Marchand
* Fabien Spindler
#include <stdio.h>
#include <stdlib.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpMath.h>
#include <visp3/io/vpParseArgv.h>
#include <visp3/robot/vpSimulatorCamera.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/visual_features/vpFeaturePoint.h>
#include <visp3/vs/vpServo.h>
// List of allowed command line options
#define GETOPTARGS "h"
void usage(const char *name, const char *badparam);
bool getOptions(int argc, const char **argv);
void usage(const char *name, const char *badparam)
fprintf(stdout, "\n\
Simulation of a 2D visual servoing on a point:\n\
- eye-in-hand control law,\n\
- articular velocity are computed,\n\
- without display,\n\
- only the X coordinate of the point is selected.\n\
%s [-h]\n",
fprintf(stdout, "\n\
OPTIONS: Default\n\
Print the help.\n");
if (badparam)
fprintf(stdout, "\nERROR: Bad parameter [%s]\n", badparam);
bool getOptions(int argc, const char **argv)
const char *optarg_;
int c;
while ((c = vpParseArgv::parse(argc, argv, GETOPTARGS, &optarg_)) > 1) {
switch (c) {
case 'h':
usage(argv[0], NULL);
return false;
usage(argv[0], optarg_);
return false;
if ((c == 1) || (c == -1)) {
// standalone param or error
usage(argv[0], NULL);
std::cerr << "ERROR: " << std::endl;
std::cerr << " Bad argument " << optarg_ << std::endl << std::endl;
return false;
return true;
int main(int argc, const char **argv)
#if (defined(VISP_HAVE_LAPACK) || defined(VISP_HAVE_EIGEN3) || defined(VISP_HAVE_OPENCV))
try {
// Read the command line options
if (getOptions(argc, argv) == false) {
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, articular velocity are computed" << std::endl;
std::cout << " Simulation " << std::endl;
std::cout << " task : servo a point " << std::endl;
std::cout << "-------------------------------------------------------" << std::endl;
std::cout << std::endl;
// sets the initial camera location
cMo[0][3] = 0.1;
cMo[1][3] = 0.2;
cMo[2][3] = 2;
// Compute the position of the object in the world frame
wMo = wMc * cMo;
// sets the point coordinates in the world frame
vpPoint point(0, 0, 0);
// computes the point coordinates in the camera frame and its 2D
// coordinates
// sets the current position of the visual feature
vpFeatureBuilder::create(p, point); // retrieve x,y and Z of the vpPoint structure
// sets the desired position of the visual feature
pd.buildFrom(0, 0, 1); // buildFrom(x,y,Z) ;
// define the task
// - we want an eye-in-hand control law
// - articular velocity are computed
// Set the position of the end-effector frame in the camera frame as identity
// Set the Jacobian (expressed in the end-effector frame)
vpMatrix eJe;
// we want to see a point on a point
// set the gain
// Display task information
unsigned int iter = 0;
// loop
while (iter++ < 100) {
std::cout << "---------------------------------------------" << iter << std::endl;
// Set the Jacobian (expressed in the end-effector frame)
// since q is modified eJe is modified
// get the robot position
// Compute the position of the object frame in the camera frame
cMo = wMc.inverse() * wMo;
// new point position
vpFeatureBuilder::create(p, point); // retrieve x,y and Z of the vpPoint structure
// compute the control law
v = task.computeControlLaw();
// send the camera velocity to the controller
std::cout << "|| s - s* || = " << (task.getError()).sumSquare() << std::endl;
// Display task information
} catch (const vpException &e) {
std::cout << "Catch a ViSP exception: " << e << std::endl;
std::cout << "Cannot run this example: install Lapack, Eigen3 or OpenCV" << std::endl;
Implementation of column vector and the associated operations.
Definition: vpColVector.h:131
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 point visual feature which is composed by two parameters that are the cartes...
void buildFrom(double x, double y, double Z)
static unsigned int selectX()
Implementation of an homogeneous matrix and operations on such kind of matrices.
vpHomogeneousMatrix inverse() const
Implementation of a matrix and operations on matrices.
Definition: vpMatrix.h:154
static bool parse(int *argcPtr, const char **argv, vpArgvInfo *argTable, int flags)
Definition: vpParseArgv.cpp:69
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 setVelocity(const vpRobot::vpControlFrameType frame, const vpColVector &vel)
void get_eJe(vpMatrix &eJe)
Definition: vpRobot.h:83
Definition: vpServo.h:159
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
void addFeature(vpBasicFeature &s, vpBasicFeature &s_star, unsigned int select=vpBasicFeature::FEATURE_ALL)
Definition: vpServo.cpp:487
Class that defines the simplest robot: a free flying camera.