Visual Servoing Platform  version 3.2.1 under development (2019-11-19)
servoFrankaIBVS.cpp

Example of eye-in-hand image-based control law. We control here a real robot, the Franka Emika Panda robot (arm with 7 degrees of freedom). The velocity is computed in the camera frame. The inverse jacobian that converts cartesian velocities in joint velocities is implemented in the robot low level controller. Visual features are the image coordinates of 4 points corresponding too the corners of an AprilTag.

The device used to acquire images is a Realsense SR300 device.

Camera extrinsic (eMc) parameters are set by default to a value that will not match Your configuration. Use –eMc command line option to read the values from a file. This file could be obtained following extrinsic camera calibration tutorial: https://visp-doc.inria.fr/doxygen/visp-daily/tutorial-calibration-extrinsic.html

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 - 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.
*
* 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/gui/vpDisplayGDI.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/io/vpImageIo.h>
#include <visp3/sensor/vpRealSense2.h>
#include <visp3/robot/vpRobotFranka.h>
#include <visp3/detection/vpDetectorAprilTag.h>
#include <visp3/visual_features/vpFeatureBuilder.h>
#include <visp3/visual_features/vpFeaturePoint.h>
#include <visp3/vs/vpServo.h>
#include <visp3/vs/vpServoDisplay.h>
#include <visp3/gui/vpPlot.h>
#if defined(VISP_HAVE_REALSENSE2) && (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11) && \
(defined(VISP_HAVE_X11) || defined(VISP_HAVE_GDI)) && defined(VISP_HAVE_FRANKA)
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;
std::string opt_robot_ip = "192.168.1.1";
std::string opt_eMc_filename = "";
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]) == "--ip" && i + 1 < argc) {
opt_robot_ip = std::string(argv[i + 1]);
}
else if (std::string(argv[i]) == "--eMc" && i + 1 < argc) {
opt_eMc_filename = std::string(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] << " [--ip <default " << opt_robot_ip << ">] [--tag_size <marker size in meter; default " << opt_tagSize << ">] [--eMc <eMc extrinsic file>] "
<< "[--quad_decimate <decimation; default " << opt_quad_decimate << ">] [--adaptive_gain] [--plot] [--task_sequencing] [--no-convergence-threshold] [--verbose] [--help] [-h]"
<< "\n";
return EXIT_SUCCESS;
}
}
try {
robot.connect(opt_robot_ip);
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 extrinsics
// Set camera extrinsics default values
ePc[0] = 0.0337731; ePc[1] = -0.00535012; ePc[2] = -0.0523339;
ePc[3] = -0.247294; ePc[4] = -0.306729; ePc[5] = 1.53055;
// If provided, read camera extrinsics from --eMc <file>
if (!opt_eMc_filename.empty()) {
ePc.loadYAML(opt_eMc_filename, ePc);
}
else {
std::cout << "Warning, opt_eMc_filename is empty! Use hard coded values." << "\n";
}
std::cout << "eMc:\n" << eMc << "\n";
// 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();
robot.set_eMc(eMc); // Set location of the camera wrt end-effector frame
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);
}
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();
ss.str("");
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
ss.str("");
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;
}
task.kill();
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 franka::NetworkException &e) {
std::cout << "Franka network exception: " << e.what() << std::endl;
std::cout << "Check if you are connected to the Franka robot"
<< " or if you specified the right IP using --ip command line option set by default to 192.168.1.1. " << std::endl;
return EXIT_FAILURE;
}
catch(const std::exception &e) {
std::cout << "Franka exception: " << e.what() << std::endl;
return EXIT_FAILURE;
}
return 0;
}
#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_FRANKA)
std::cout << "Install libfranka." << std::endl;
#endif
return 0;
}
#endif