Visual Servoing Platform  version 3.5.1 under development (2022-10-02)
servoAfma6AprilTagIBVS.cpp

Example of eye-in-hand image-based control law. We control here the Afma6 robot at Inria. The velocity is computed in the camera frame. Visual features are the image coordinates of 4 points corresponding to the corners of an AprilTag.

The device used to acquire images is a Realsense D435 device.

Camera intrinsic parameters are retrieved from the Realsense SDK.

The target is an AprilTag that is by default 12cm large. To print your own tag, see https://visp-doc.inria.fr/doxygen/visp-daily/tutorial-detection-apriltag.html You can specify the size of your tag using –tag_size command line option.

/****************************************************************************
*
* ViSP, open source Visual Servoing Platform software.
* Copyright (C) 2005 - 2022 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.
*
* For using ViSP with software that can not be combined with the GNU
* GPL, please contact Inria about acquiring a ViSP Professional
* Edition License.
*
* See http://visp.inria.fr for more information.
*
* This software was developed at:
* Inria Rennes - Bretagne Atlantique
* Campus Universitaire de Beaulieu
* 35042 Rennes Cedex
* France
*
* If you have questions regarding the use of this file, please contact
* Inria at visp@inria.fr
*
* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Description:
* tests the control law
* eye-in-hand control
* velocity computed in the camera frame
*
* Authors:
* Fabien Spindler
*
*****************************************************************************/
#include <iostream>
#include <visp3/core/vpCameraParameters.h>
#include <visp3/detection/vpDetectorAprilTag.h>
#include <visp3/gui/vpDisplayGDI.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/gui/vpPlot.h>
#include <visp3/io/vpImageIo.h>
#include <visp3/robot/vpRobotAfma6.h>
#include <visp3/sensor/vpRealSense2.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/visual_features/vpFeaturePoint.h>
#include <visp3/vs/vpServo.h>
#include <visp3/vs/vpServoDisplay.h>
#if defined(VISP_HAVE_REALSENSE2) && (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11) && \
(defined(VISP_HAVE_X11) || defined(VISP_HAVE_GDI)) && defined(VISP_HAVE_AFMA6)
void display_point_trajectory(const vpImage<unsigned char> &I, const std::vector<vpImagePoint> &vip,
std::vector<vpImagePoint> *traj_vip)
{
for (size_t i = 0; i < vip.size(); i++) {
if (traj_vip[i].size()) {
// Add the point only if distance with the previous > 1 pixel
if (vpImagePoint::distance(vip[i], traj_vip[i].back()) > 1.) {
traj_vip[i].push_back(vip[i]);
}
} else {
traj_vip[i].push_back(vip[i]);
}
}
for (size_t i = 0; i < vip.size(); i++) {
for (size_t j = 1; j < traj_vip[i].size(); j++) {
vpDisplay::displayLine(I, traj_vip[i][j - 1], traj_vip[i][j], vpColor::green, 2);
}
}
}
int main(int argc, char **argv)
{
double opt_tagSize = 0.120;
bool display_tag = true;
int opt_quad_decimate = 2;
bool opt_verbose = false;
bool opt_plot = false;
bool opt_adaptive_gain = false;
bool opt_task_sequencing = false;
double convergence_threshold = 0.00005;
for (int i = 1; i < argc; i++) {
if (std::string(argv[i]) == "--tag_size" && i + 1 < argc) {
opt_tagSize = std::stod(argv[i + 1]);
} else if (std::string(argv[i]) == "--verbose") {
opt_verbose = true;
} else if (std::string(argv[i]) == "--plot") {
opt_plot = true;
} else if (std::string(argv[i]) == "--adaptive_gain") {
opt_adaptive_gain = true;
} else if (std::string(argv[i]) == "--task_sequencing") {
opt_task_sequencing = true;
} else if (std::string(argv[i]) == "--quad_decimate" && i + 1 < argc) {
opt_quad_decimate = std::stoi(argv[i + 1]);
} else if (std::string(argv[i]) == "--no-convergence-threshold") {
convergence_threshold = 0.;
} else if (std::string(argv[i]) == "--help" || std::string(argv[i]) == "-h") {
std::cout
<< argv[0] << " --tag_size <marker size in meter; default " << opt_tagSize << ">] "
<< "[--quad_decimate <decimation; default " << opt_quad_decimate
<< ">] [--adaptive_gain] [--plot] [--task_sequencing] [--no-convergence-threshold] [--verbose] [--help] [-h]"
<< "\n";
return EXIT_SUCCESS;
}
}
vpRobotAfma6 robot;
try {
std::cout << "WARNING: This example will move the robot! "
<< "Please make sure to have the user stop button at hand!" << std::endl
<< "Press Enter to continue..." << std::endl;
std::cin.ignore();
/*
* Move to a safe position
*/
vpColVector q(6, 0);
q[0] = 0.;
q[1] = 0.;
q[2] = 0.;
q[3] = vpMath::rad(0.);
q[4] = vpMath::rad(0.);
q[5] = vpMath::rad(0.);
std::cout << "Move to joint position: " << q.t() << std::endl;
robot.setPosition(vpRobot::JOINT_STATE, q);
rs2::config config;
unsigned int width = 640, height = 480;
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);
rs.open(config);
// Get camera intrinsics
std::cout << "cam:\n" << cam << "\n";
vpImage<unsigned char> I(height, width);
#if defined(VISP_HAVE_X11)
vpDisplayX dc(I, 10, 10, "Color image");
#elif defined(VISP_HAVE_GDI)
vpDisplayGDI dc(I, 10, 10, "Color image");
#endif
// vpDetectorAprilTag::vpPoseEstimationMethod poseEstimationMethod = vpDetectorAprilTag::BEST_RESIDUAL_VIRTUAL_VS;
vpDetectorAprilTag detector(tagFamily);
detector.setAprilTagPoseEstimationMethod(poseEstimationMethod);
detector.setDisplayTag(display_tag);
detector.setAprilTagQuadDecimate(opt_quad_decimate);
// Servo
vpHomogeneousMatrix cdMc, cMo, oMo;
// Desired pose used to compute the desired features
vpHomogeneousMatrix cdMo(vpTranslationVector(0, 0, opt_tagSize * 3), // 3 times tag with along camera z axis
vpRotationMatrix({1, 0, 0, 0, -1, 0, 0, 0, -1}));
// Create visual features
std::vector<vpFeaturePoint> p(4), pd(4); // We use 4 points
// Define 4 3D points corresponding to the CAD model of the Apriltag
std::vector<vpPoint> point(4);
point[0].setWorldCoordinates(-opt_tagSize / 2., -opt_tagSize / 2., 0);
point[1].setWorldCoordinates(opt_tagSize / 2., -opt_tagSize / 2., 0);
point[2].setWorldCoordinates(opt_tagSize / 2., opt_tagSize / 2., 0);
point[3].setWorldCoordinates(-opt_tagSize / 2., opt_tagSize / 2., 0);
vpServo task;
// Add the 4 visual feature points
for (size_t i = 0; i < p.size(); i++) {
task.addFeature(p[i], pd[i]);
}
if (opt_adaptive_gain) {
vpAdaptiveGain lambda(1.5, 0.4, 30); // lambda(0)=4, lambda(oo)=0.4 and lambda'(0)=30
task.setLambda(lambda);
} else {
task.setLambda(0.5);
}
vpPlot *plotter = nullptr;
int iter_plot = 0;
if (opt_plot) {
plotter = new vpPlot(2, static_cast<int>(250 * 2), 500, static_cast<int>(I.getWidth()) + 80, 10,
"Real time curves plotter");
plotter->setTitle(0, "Visual features error");
plotter->setTitle(1, "Camera velocities");
plotter->initGraph(0, 8);
plotter->initGraph(1, 6);
plotter->setLegend(0, 0, "error_feat_p1_x");
plotter->setLegend(0, 1, "error_feat_p1_y");
plotter->setLegend(0, 2, "error_feat_p2_x");
plotter->setLegend(0, 3, "error_feat_p2_y");
plotter->setLegend(0, 4, "error_feat_p3_x");
plotter->setLegend(0, 5, "error_feat_p3_y");
plotter->setLegend(0, 6, "error_feat_p4_x");
plotter->setLegend(0, 7, "error_feat_p4_y");
plotter->setLegend(1, 0, "vc_x");
plotter->setLegend(1, 1, "vc_y");
plotter->setLegend(1, 2, "vc_z");
plotter->setLegend(1, 3, "wc_x");
plotter->setLegend(1, 4, "wc_y");
plotter->setLegend(1, 5, "wc_z");
}
bool final_quit = false;
bool has_converged = false;
bool send_velocities = false;
bool servo_started = false;
std::vector<vpImagePoint> *traj_corners = nullptr; // To memorize point trajectory
static double t_init_servo = vpTime::measureTimeMs();
while (!has_converged && !final_quit) {
double t_start = vpTime::measureTimeMs();
rs.acquire(I);
std::vector<vpHomogeneousMatrix> cMo_vec;
detector.detect(I, opt_tagSize, cam, cMo_vec);
{
std::stringstream ss;
ss << "Left click to " << (send_velocities ? "stop the robot" : "servo the robot") << ", right click to quit.";
vpDisplay::displayText(I, 20, 20, ss.str(), vpColor::red);
}
vpColVector v_c(6);
// Only one tag is detected
if (cMo_vec.size() == 1) {
cMo = cMo_vec[0];
static bool first_time = true;
if (first_time) {
// Introduce security wrt tag positionning in order to avoid PI rotation
std::vector<vpHomogeneousMatrix> v_oMo(2), v_cdMc(2);
v_oMo[1].buildFrom(0, 0, 0, 0, 0, M_PI);
for (size_t i = 0; i < 2; i++) {
v_cdMc[i] = cdMo * v_oMo[i] * cMo.inverse();
}
if (std::fabs(v_cdMc[0].getThetaUVector().getTheta()) < std::fabs(v_cdMc[1].getThetaUVector().getTheta())) {
oMo = v_oMo[0];
} else {
std::cout << "Desired frame modified to avoid PI rotation of the camera" << std::endl;
oMo = v_oMo[1]; // Introduce PI rotation
}
// Compute the desired position of the features from the desired pose
for (size_t i = 0; i < point.size(); i++) {
vpColVector cP, p_;
point[i].changeFrame(cdMo * oMo, cP);
point[i].projection(cP, p_);
pd[i].set_x(p_[0]);
pd[i].set_y(p_[1]);
pd[i].set_Z(cP[2]);
}
}
// Get tag corners
std::vector<vpImagePoint> corners = detector.getPolygon(0);
// Update visual features
for (size_t i = 0; i < corners.size(); i++) {
// Update the point feature from the tag corners location
vpFeatureBuilder::create(p[i], cam, corners[i]);
// Set the feature Z coordinate from the pose
point[i].changeFrame(cMo, cP);
p[i].set_Z(cP[2]);
}
if (opt_task_sequencing) {
if (!servo_started) {
if (send_velocities) {
servo_started = true;
}
t_init_servo = vpTime::measureTimeMs();
}
v_c = task.computeControlLaw((vpTime::measureTimeMs() - t_init_servo) / 1000.);
} else {
v_c = task.computeControlLaw();
}
// Display the current and desired feature points in the image display
vpServoDisplay::display(task, cam, I);
for (size_t i = 0; i < corners.size(); i++) {
std::stringstream ss;
ss << i;
// Display current point indexes
vpDisplay::displayText(I, corners[i] + vpImagePoint(15, 15), ss.str(), vpColor::red);
// Display desired point indexes
vpMeterPixelConversion::convertPoint(cam, pd[i].get_x(), pd[i].get_y(), ip);
vpDisplay::displayText(I, ip + vpImagePoint(15, 15), ss.str(), vpColor::red);
}
if (first_time) {
traj_corners = new std::vector<vpImagePoint>[corners.size()];
}
// Display the trajectory of the points used as features
display_point_trajectory(I, corners, traj_corners);
if (opt_plot) {
plotter->plot(0, iter_plot, task.getError());
plotter->plot(1, iter_plot, v_c);
iter_plot++;
}
if (opt_verbose) {
std::cout << "v_c: " << v_c.t() << std::endl;
}
double error = task.getError().sumSquare();
std::stringstream ss;
ss << "error: " << error;
vpDisplay::displayText(I, 20, static_cast<int>(I.getWidth()) - 150, ss.str(), vpColor::red);
if (opt_verbose)
std::cout << "error: " << error << std::endl;
if (error < convergence_threshold) {
has_converged = true;
std::cout << "Servo task has converged"
<< "\n";
vpDisplay::displayText(I, 100, 20, "Servo task has converged", vpColor::red);
}
if (first_time) {
first_time = false;
}
} // end if (cMo_vec.size() == 1)
else {
v_c = 0;
}
if (!send_velocities) {
v_c = 0;
}
// Send to the robot
{
std::stringstream ss;
ss << "Loop time: " << vpTime::measureTimeMs() - t_start << " ms";
vpDisplay::displayText(I, 40, 20, ss.str(), vpColor::red);
}
if (vpDisplay::getClick(I, button, false)) {
switch (button) {
send_velocities = !send_velocities;
break;
final_quit = true;
v_c = 0;
break;
default:
break;
}
}
}
std::cout << "Stop the robot " << std::endl;
if (opt_plot && plotter != nullptr) {
delete plotter;
plotter = nullptr;
}
if (!final_quit) {
while (!final_quit) {
rs.acquire(I);
vpDisplay::displayText(I, 20, 20, "Click to quit the program.", vpColor::red);
vpDisplay::displayText(I, 40, 20, "Visual servo converged.", vpColor::red);
if (vpDisplay::getClick(I, false)) {
final_quit = true;
}
}
}
if (traj_corners) {
delete[] traj_corners;
}
} catch (const vpException &e) {
std::cout << "ViSP exception: " << e.what() << std::endl;
std::cout << "Stop the robot " << std::endl;
return EXIT_FAILURE;
} catch (const std::exception &e) {
std::cout << "ur_rtde exception: " << e.what() << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
#else
int main()
{
#if !defined(VISP_HAVE_REALSENSE2)
std::cout << "Install librealsense-2.x" << std::endl;
#endif
#if (VISP_CXX_STANDARD < VISP_CXX_STANDARD_11)
std::cout << "Build ViSP with c++11 or higher compiler flag (cmake -DUSE_CXX_STANDARD=11)." << std::endl;
#endif
#if !defined(VISP_HAVE_AFMA6)
std::cout << "ViSP is not build with Afma6 robot support..." << std::endl;
#endif
return EXIT_SUCCESS;
}
#endif
Adaptive gain computation.
Generic class defining intrinsic camera parameters.
Implementation of column vector and the associated operations.
Definition: vpColVector.h:131
double sumSquare() const
static const vpColor red
Definition: vpColor.h:217
static const vpColor green
Definition: vpColor.h:220
@ TAG_36h11
AprilTag 36h11 pattern (recommended)
Display for windows using GDI (available on any windows 32 platform).
Definition: vpDisplayGDI.h:129
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 displayLine(const vpImage< unsigned char > &I, const vpImagePoint &ip1, const vpImagePoint &ip2, const vpColor &color, unsigned int thickness=1, bool segment=true)
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 emited by ViSP classes.
Definition: vpException.h:72
const char * what() const
Definition: vpException.cpp:99
static void create(vpFeaturePoint &s, const vpCameraParameters &cam, const vpDot &d)
Implementation of an homogeneous matrix and operations on such kind of matrices.
vpHomogeneousMatrix inverse() const
Class that defines a 2D point in an image. This class is useful for image processing and stores only ...
Definition: vpImagePoint.h:89
static double distance(const vpImagePoint &iP1, const vpImagePoint &iP2)
unsigned int getWidth() const
Definition: vpImage.h:246
static double rad(double deg)
Definition: vpMath.h:117
static void convertPoint(const vpCameraParameters &cam, const double &x, const double &y, double &u, double &v)
This class enables real time drawing of 2D or 3D graphics. An instance of the class open a window whi...
Definition: vpPlot.h:116
void initGraph(unsigned int graphNum, unsigned int curveNbr)
Definition: vpPlot.cpp:205
void setLegend(unsigned int graphNum, unsigned int curveNum, const std::string &legend)
Definition: vpPlot.cpp:534
void plot(unsigned int graphNum, unsigned int curveNum, double x, double y)
Definition: vpPlot.cpp:285
void setTitle(unsigned int graphNum, const std::string &title)
Definition: vpPlot.cpp:497
void acquire(vpImage< unsigned char > &grey, double *ts=NULL)
vpCameraParameters getCameraParameters(const rs2_stream &stream, vpCameraParameters::vpCameraParametersProjType type=vpCameraParameters::perspectiveProjWithDistortion, int index=-1) const
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)
@ JOINT_STATE
Definition: vpRobot.h:81
@ CAMERA_FRAME
Definition: vpRobot.h:83
@ STATE_POSITION_CONTROL
Initialize the position controller.
Definition: vpRobot.h:68
@ STATE_VELOCITY_CONTROL
Initialize the velocity controller.
Definition: vpRobot.h:67
@ STATE_STOP
Stops robot motion especially in velocity and acceleration control.
Definition: vpRobot.h:66
virtual vpRobotStateType setRobotState(const vpRobot::vpRobotStateType newState)
Definition: vpRobot.cpp:201
Implementation of a rotation matrix and operations on such kind of matrices.
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
@ EYEINHAND_CAMERA
Definition: vpServo.h:155
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
vpColVector computeControlLaw()
Definition: vpServo.cpp:926
@ CURRENT
Definition: vpServo.h:182
void addFeature(vpBasicFeature &s, vpBasicFeature &s_star, unsigned int select=vpBasicFeature::FEATURE_ALL)
Definition: vpServo.cpp:487
Class that consider the case of a translation vector.
VISP_EXPORT double measureTimeMs()