orocos / orocos_kinematics_dynamics

Orocos Kinematics and Dynamics C++ library
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Problem with path_line trajectory, C code, bad quaternions in trajectory #453

Open ketchup007 opened 1 year ago

ketchup007 commented 1 year ago

I have problem with easy path line trajectory. Only move i z axis, both orientations are the same. But in trajectory I see changes in quaternions.

I rewrite Yours example to show issue:

#include <kdl/frames.hpp>
#include <kdl/frames_io.hpp>
#include <kdl/trajectory.hpp>
#include <kdl/trajectory_segment.hpp>
#include <kdl/trajectory_stationary.hpp>
#include <kdl/trajectory_composite.hpp>
#include <kdl/trajectory_composite.hpp>
#include <kdl/velocityprofile_trap.hpp>
#include <kdl/path_line.hpp>
#include <kdl/rotational_interpolation_sa.hpp>
#include <kdl/utilities/error.h>
#include <kdl/trajectory_composite.hpp>

int main(int argc,char* argv[]) {
    using namespace KDL;
    try {
        KDL::Frame start_frame(KDL::Rotation::Quaternion(0.70711, 0.70711, 0, 0), KDL::Vector(0.8, 0.5, 0.3));
        KDL::Frame end_frame  (KDL::Rotation::Quaternion(0.70711, 0.70711, 0, 0), KDL::Vector(0.8, 0.5, 0.3));
        KDL::Path_Line* path = new KDL::Path_Line(start_frame, end_frame, new KDL::RotationalInterpolation_SingleAxis(), 0.0, true);

        VelocityProfile* velpref = new VelocityProfile_Trap(0.5,0.1);
        velpref->SetProfile(0, path->PathLength());  

        Trajectory* traject = new Trajectory_Segment(path, velpref);

        // use the trajectory
        double dt=0.1;
        std::ofstream of("./trajectory.dat");
        for (double t=0.0; t <= traject->Duration(); t+= dt) {
            Frame current_pose;
            current_pose = traject->Pos(t);

                        // Pobranie pozycji x, y, z
                        double x = current_pose.p.x();
                        double y = current_pose.p.y();
                        double z = current_pose.p.z();

                        // Pobranie orientacji jako kwaternion
                        double qx, qy, qz, qw;
                        current_pose.M.GetQuaternion(qx, qy, qz, qw);

                        // Zapisanie pozycji i orientacji do pliku
                        of << x << "\t" << y << "\t" << z << "\t" << qx << "\t" << qy << "\t" << qz << "\t" << qw << "\n";

        }
        of.close();

        std::cout << " trajectory written to the ./trajectory.dat file " << std::endl;

        delete traject;
    } catch(Error& error) {
        std::cout <<"I encountered this error : " << error.Description() << std::endl;
        std::cout << "with the following type " << error.GetType() << std::endl;
    }

}

and the output is:

0.8 0.5 0   0.707112    0.707108    0   0
0.8 0.5 0.0005  0.708957    0.705258    0   0
0.8 0.5 0.002   0.714474    0.699668    0   0
0.8 0.5 0.0045  0.723572    0.690256    0   0
0.8 0.5 0.008   0.736099    0.67688 0   0
0.8 0.5 0.0125  0.751842    0.65935 0   0
0.8 0.5 0.018   0.770516    0.637428    0   0
0.8 0.5 0.0245  0.791759    0.61084 0   0
0.8 0.5 0.032   0.815131    0.579284    0   0
0.8 0.5 0.0405  0.840097    0.542444    0   0
0.8 0.5 0.05    0.866029    0.500003    0   0
0.8 0.5 0.0605  0.892196    0.451658    0   0
0.8 0.5 0.072   0.917759    0.39715 0   0
0.8 0.5 0.0845  0.941769    0.336275    0   0
0.8 0.5 0.098   0.963167    0.268921    0   0
0.8 0.5 0.1125  0.98079 0.195091    0   0
0.8 0.5 0.128   0.993378    0.114938    0   0
0.8 0.5 0.1445  0.999591    0.0287941   0   0
0.8 0.5 0.161538    0.998181    -0.0603778  0   -0
0.8 0.5 0.177679    0.989522    -0.144422   0   -0
0.8 0.5 0.19282 0.974977    -0.222334   0   -0
0.8 0.5 0.206961    0.955859    -0.293848   0   -0
0.8 0.5 0.220102    0.933394    -0.358869   0   -0
0.8 0.5 0.232243    0.908711    -0.41744    0   -0
0.8 0.5 0.243384    0.882828    -0.469709   0   -0
0.8 0.5 0.253525    0.856655    -0.515901   0   -0
0.8 0.5 0.262666    0.830991    -0.556296   0   -0
0.8 0.5 0.270807    0.80653 -0.591202   0   -0
0.8 0.5 0.277948    0.783866    -0.620938   0   -0
0.8 0.5 0.284089    0.763499    -0.645817   0   -0
0.8 0.5 0.28923 0.74584 -0.666132   0   -0
0.8 0.5 0.293372    0.731222    -0.682146   0   -0
0.8 0.5 0.296513    0.719905    -0.694079   0   -0
0.8 0.5 0.298654    0.712079    -0.702106   0   -0
0.8 0.5 0.299795    0.707872    -0.706347   0   -0