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 Afma4 robot (cylindrical robot, with 4 degrees of freedom). The velocity is computed in articular. The visual feature is the center of gravity of a point.

* 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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* This software was developed at:
* Inria Rennes - Bretagne Atlantique
* Campus Universitaire de Beaulieu
* 35042 Rennes Cedex
* France
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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 articular
* Authors:
* Eric Marchand
* Fabien Spindler
#include <fstream>
#include <iostream>
#include <sstream>
#include <stdio.h>
#include <stdlib.h>
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpDebug.h> // Debug trace
#if (defined(VISP_HAVE_AFMA4) && defined(VISP_HAVE_DC1394))
#include <visp3/core/vpDisplay.h>
#include <visp3/core/vpImage.h>
#include <visp3/core/vpImagePoint.h>
#include <visp3/gui/vpDisplayGTK.h>
#include <visp3/gui/vpDisplayOpenCV.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/sensor/vp1394TwoGrabber.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpIoTools.h>
#include <visp3/core/vpMath.h>
#include <visp3/core/vpPoint.h>
#include <visp3/robot/vpRobotAfma4.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/visual_features/vpFeaturePoint.h>
#include <visp3/vs/vpServo.h>
// Exception
#include <visp3/core/vpException.h>
#include <visp3/vs/vpServoDisplay.h>
#include <visp3/blob/vpDot.h>
int main()
try {
// Log file creation in /tmp/$USERNAME/log.dat
// This file contains by line:
// - the 6 computed joint velocities (m/s, rad/s) to achieve the task
// - the 6 mesured joint velocities (m/s, rad/s)
// - the 6 mesured joint positions (m, rad)
// - the 2 values of s - s*
std::string username;
// Get the user login name
// Create a log filename to save velocities...
std::string logdirname;
logdirname = "/tmp/" + username;
// Test if the output path exist. If no try to create it
if (vpIoTools::checkDirectory(logdirname) == false) {
try {
// Create the dirname
} catch (...) {
std::cerr << std::endl << "ERROR:" << std::endl;
std::cerr << " Cannot create " << logdirname << std::endl;
std::string logfilename;
logfilename = logdirname + "/log.dat";
// Open the log file name
std::ofstream flog(logfilename.c_str());
// vpRobotAfma4 robot ;
vpRobotAfma4 robot;
vpServo task;;
#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");
// exit(1) ;
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 joint space" << std::endl;
std::cout << " Use of the Afma4 robot " << std::endl;
std::cout << " task : servo a point " << std::endl;
std::cout << "-------------------------------------------------------" << std::endl;
std::cout << std::endl;
vpDot dot;
std::cout << "Click on a dot..." << std::endl;
vpImagePoint cog = dot.getCog();
// Update camera parameters
// robot.getCameraParameters (cam, I);
vpTRACE("sets the current position of the visual feature ");
vpFeatureBuilder::create(p, cam, dot); // retrieve x,y and Z of the vpPoint structure
vpTRACE("sets the desired position of the visual feature ");
pd.buildFrom(0, 0, 1);
vpTRACE("define the task");
vpTRACE("\t we want an eye-in-hand control law");
vpTRACE("\t articular velocity are computed");
vpTRACE("Set the position of the end-effector frame in the camera frame");
// robot.get_cMe(cMe) ;
std::cout << cVe << std::endl;
// vpDisplay::getClick(I) ;
vpTRACE("Set the Jacobian (expressed in the end-effector frame)");
vpMatrix eJe;
vpTRACE("\t we want to see a point on a point..");
std::cout << std::endl;
task.addFeature(p, pd);
vpTRACE("\t set the gain");
vpTRACE("Display task information ");
std::cout << "\nHit CTRL-C to stop the loop...\n" << std::flush;
for (;;) {
// Acquire a new image from the camera
// Display this image
// Achieve the tracking of the dot in the image
// Get the cog of the dot
cog = dot.getCog();
// Display a green cross at the center of gravity position in the image
// Update the point feature from the dot location
// Get the jacobian of the robot
// Update this jacobian in the task structure. It will be used to
// compute the velocity skew (as an articular velocity) qdot = -lambda *
// L^+ * cVe * eJe * (s-s*)
// std::cout << (vpMatrix)cVe*eJe << std::endl ;
// Compute the visual servoing skew vector
v = task.computeControlLaw();
// Display the current and desired feature points in the image display
vpServoDisplay::display(task, cam, I);
// Apply the computed joint velocities to the robot
// Save velocities applied to the robot in the log file
// v[0], v[1], v[2] correspond to joint translation velocities in m/s
// v[3], v[4], v[5] correspond to joint rotation velocities in rad/s
flog << v[0] << " " << v[1] << " " << v[2] << " " << v[3] << " " << v[4] << " " << v[5] << " ";
// Get the measured joint velocities of the robot
// Save measured joint velocities of the robot in the log file:
// - qvel[0], qvel[1], qvel[2] correspond to measured joint translation
// velocities in m/s
// - qvel[3], qvel[4], qvel[5] correspond to measured joint rotation
// velocities in rad/s
flog << qvel[0] << " " << qvel[1] << " " << qvel[2] << " " << qvel[3] << " " << qvel[4] << " " << qvel[5] << " ";
// Get the measured joint positions of the robot
robot.getPosition(vpRobot::ARTICULAR_FRAME, q);
// Save measured joint positions of the robot in the log file
// - q[0], q[1], q[2] correspond to measured joint translation
// positions in m
// - q[3], q[4], q[5] correspond to measured joint rotation
// positions in rad
flog << q[0] << " " << q[1] << " " << q[2] << " " << q[3] << " " << q[4] << " " << q[5] << " ";
// Save feature error (s-s*) for the feature point. For this feature
// point, we have 2 errors (along x and y axis). This error is
// expressed in meters in the camera frame
flog << task.getError() << std::endl;
// vpTRACE("\t\t || s - s* || = %f ", ( task.getError()
// ).sumSquare()) ;
flog.close(); // Close the log file
vpTRACE("Display task information ");
} catch (const vpException &e) {
std::cout << "Catch a ViSP exception: " << e << std::endl;
int main()
std::cout << "You do not have an afma4 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 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 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)
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
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
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)
void set_Z(double Z)
Implementation of an homogeneous matrix and operations on such kind of matrices.
Class that defines a 2D point in an image. This class is useful for image processing and stores only ...
Definition: vpImagePoint.h:89
static bool checkDirectory(const std::string &dirname)
Definition: vpIoTools.cpp:418
static std::string getUserName()
Definition: vpIoTools.cpp:314
static void makeDirectory(const std::string &dirname)
Definition: vpIoTools.cpp:568
Implementation of a matrix and operations on matrices.
Definition: vpMatrix.h:154
Control of Irisa's cylindrical robot named Afma4.
Definition: vpRobotAfma4.h:179
void setVelocity(const vpRobot::vpControlFrameType frame, const vpColVector &vel)
void getVelocity(const vpRobot::vpControlFrameType frame, vpColVector &velocity)
void get_eJe(vpMatrix &eJe)
Definition: vpRobot.h:79
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: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
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
vpVelocityTwistMatrix get_cVe() const
Definition: vpUnicycle.h:82
#define vpTRACE
Definition: vpDebug.h:416