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 correspond to the 3D pose of the target (an AprilTag) in the camera frame.
The device used to acquire images is a Realsense D435 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.
#include <iostream>
#include <visp3/core/vpCameraParameters.h>
#include <visp3/core/vpConfig.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/vpRobotFranka.h>
#include <visp3/sensor/vpRealSense2.h>
#include <visp3/visual_features/vpFeatureThetaU.h>
#include <visp3/visual_features/vpFeatureTranslation.h>
#include <visp3/vs/vpServo.h>
#include <visp3/vs/vpServoDisplay.h>
#if defined(VISP_HAVE_REALSENSE2) && (defined(VISP_HAVE_X11) || defined(VISP_HAVE_GDI)) && defined(VISP_HAVE_FRANKA)
#ifdef ENABLE_VISP_NAMESPACE
#endif
std::vector<vpImagePoint> *traj_vip)
{
for (size_t i = 0; i < vip.size(); i++) {
if (traj_vip[i].size()) {
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++) {
}
}
}
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_t = 0.0005;
double convergence_threshold_tu = 0.5;
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_t = 0.;
convergence_threshold_tu = 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);
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 (!opt_eMc_filename.empty()) {
}
else {
std::cout << "Warning, opt_eMc_filename is empty! Use hard coded values."
<< "\n";
}
std::cout << "eMc:\n" << eMc << "\n";
std::cout << "cam:\n" << cam << "\n";
#if defined(VISP_HAVE_X11)
vpDisplayX dc(I, 10, 10, "Color image");
#elif defined(VISP_HAVE_GDI)
#endif
detector.setAprilTagPoseEstimationMethod(poseEstimationMethod);
detector.setDisplayTag(display_tag);
detector.setAprilTagQuadDecimate(opt_quad_decimate);
t.buildFrom(cdMc);
tu.buildFrom(cdMc);
if (opt_adaptive_gain) {
}
else {
}
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->
setLegend(0, 3,
"error_feat_theta_ux");
plotter->
setLegend(0, 4,
"error_feat_theta_uy");
plotter->
setLegend(0, 5,
"error_feat_theta_uz");
}
bool final_quit = false;
bool has_converged = false;
bool send_velocities = false;
bool servo_started = false;
std::vector<vpImagePoint> *traj_vip = nullptr;
robot.set_eMc(eMc);
while (!has_converged && !final_quit) {
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.";
if (cMo_vec.size() == 1) {
cMo = cMo_vec[0];
static bool first_time = true;
if (first_time) {
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];
}
}
if (opt_task_sequencing) {
if (!servo_started) {
if (send_velocities) {
servo_started = true;
}
}
}
else {
}
std::vector<vpImagePoint> vip = detector.getPolygon(0);
vip.push_back(detector.getCog(0));
if (first_time) {
traj_vip = new std::vector<vpImagePoint>[vip.size()];
}
display_point_trajectory(I, vip, traj_vip);
if (opt_plot) {
plotter->
plot(1, iter_plot, v_c);
iter_plot++;
}
if (opt_verbose) {
std::cout << "v_c: " << v_c.t() << std::endl;
}
ss.str("");
ss << "error_t: " << error_tr;
ss.str("");
ss << "error_tu: " << error_tu;
if (opt_verbose)
std::cout << "error translation: " << error_tr << " ; error rotation: " << error_tu << std::endl;
if (error_tr < convergence_threshold_t && error_tu < convergence_threshold_tu) {
has_converged = true;
std::cout << "Servo task has converged" << std::endl;
;
}
if (first_time) {
first_time = false;
}
}
else {
v_c = 0;
}
if (!send_velocities) {
v_c = 0;
}
ss.str("");
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) {
final_quit = true;
}
}
}
if (traj_vip) {
delete[] traj_vip;
}
}
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 EXIT_SUCCESS;
}
#else
int main()
{
#if !defined(VISP_HAVE_REALSENSE2)
std::cout << "Install librealsense-2.x" << std::endl;
#endif
#if !defined(VISP_HAVE_FRANKA)
std::cout << "Install libfranka." << std::endl;
#endif
return EXIT_SUCCESS;
}
#endif
Adaptive gain computation.
static bool loadYAML(const std::string &filename, vpArray2D< Type > &A, char *header=nullptr)
Generic class defining intrinsic camera parameters.
@ perspectiveProjWithDistortion
Perspective projection with distortion model.
Implementation of column vector and the associated operations.
static const vpColor none
static const vpColor yellow
static const vpColor green
@ TAG_36h11
AprilTag 36h11 pattern (recommended)
Display for windows using GDI (available on any windows 32 platform).
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 displayFrame(const vpImage< unsigned char > &I, const vpHomogeneousMatrix &cMo, const vpCameraParameters &cam, double size, const vpColor &color=vpColor::none, unsigned int thickness=1, const vpImagePoint &offset=vpImagePoint(0, 0), const std::string &frameName="", const vpColor &textColor=vpColor::black, const vpImagePoint &textOffset=vpImagePoint(15, 15))
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 emitted by ViSP classes.
const char * what() const
Class that defines a 3D visual feature from a axis/angle parametrization that represent the rotatio...
Class that defines the translation visual feature .
Implementation of an homogeneous matrix and operations on such kind of matrices.
vpThetaUVector getThetaUVector() const
vpHomogeneousMatrix & buildFrom(const vpTranslationVector &t, const vpRotationMatrix &R)
vpHomogeneousMatrix inverse() const
vpTranslationVector getTranslationVector() const
static double distance(const vpImagePoint &iP1, const vpImagePoint &iP2)
unsigned int getWidth() const
static double deg(double rad)
This class enables real time drawing of 2D or 3D graphics. An instance of the class open a window whi...
void initGraph(unsigned int graphNum, unsigned int curveNbr)
void setLegend(unsigned int graphNum, unsigned int curveNum, const std::string &legend)
void plot(unsigned int graphNum, unsigned int curveNum, double x, double y)
void setTitle(unsigned int graphNum, const std::string &title)
Implementation of a pose vector and operations on poses.
vpCameraParameters getCameraParameters(const rs2_stream &stream, vpCameraParameters::vpCameraParametersProjType type=vpCameraParameters::perspectiveProjWithDistortion, int index=-1) const
void acquire(vpImage< unsigned char > &grey, double *ts=nullptr)
bool open(const rs2::config &cfg=rs2::config())
void setVelocity(const vpRobot::vpControlFrameType frame, const vpColVector &vel) VP_OVERRIDE
@ STATE_VELOCITY_CONTROL
Initialize the velocity controller.
@ STATE_STOP
Stops robot motion especially in velocity and acceleration control.
virtual vpRobotStateType setRobotState(const vpRobot::vpRobotStateType newState)
Implementation of a rotation matrix and operations on such kind of matrices.
void setInteractionMatrixType(const vpServoIteractionMatrixType &interactionMatrixType, const vpServoInversionType &interactionMatrixInversion=PSEUDO_INVERSE)
void addFeature(vpBasicFeature &s_cur, vpBasicFeature &s_star, unsigned int select=vpBasicFeature::FEATURE_ALL)
void setServo(const vpServoType &servo_type)
vpColVector getError() const
vpColVector computeControlLaw()
Implementation of a rotation vector as axis-angle minimal representation.
Class that consider the case of a translation vector.
VISP_EXPORT double measureTimeMs()