Hi, thanks for your work.

I was trying to use the IKFast IK for the UR3e, but I noticed that for axis-aligned orientations, the solver does not return a joint configuration, although there clearly are joint configurations available.

Have you also encountered this? And have you by any chance found a solution? I've found that adding some noise on the quaternion (which results in non-zero values for all components) seems to overcome this, but that's quite an ugly hack imo.

you can recreate this yourself using following snippet:

if __name__ == "__main__":
    ur3e_arm = ur_kinematics.URKinematics('ur3e')

    """
    IKFast seems to struggle with quaternions along axis?
    also note that the order for the wrapper is w,x,y,z!
    """
    pose_quat =  [-0.2,-0.2,0.2,  0.0,1.0,0.0,0] # top-down EEF
    print("inverse() one from quat", ur3e_arm.inverse(pose_quat, False, q_guess=joint_angles))

    pose_quat[4:] += np.random.randn(3) * 0.01
    print("inverse() one from noisy quat", ur3e_arm.inverse(pose_quat, False, q_guess=joint_angles))

Hi, thank you for this practical and so-far-nice-working repo :)
Today I was trying to build this module on my brand new ubuntu (22.04) OS and got the error below. I thought it might be related to gcc version because it is 9.4.0 on other pc that I built the module flawlessly and now I am trying to build it on new pc which has 11.4.0. After installing gxx=9.4.0 on a mamba environment nothing changed.
What should I check, what do you say?

ur3e/ur3e_ikfast61.cpp:107156:8: warning: unused variable ‘gconst69’ [-Wunused-variable]
107156 | IkReal gconst69=((3.14159265358979)+(((-1.0)*x15683)));
       |        ^~~~~~~~
ur3e/ur3e_ikfast61.cpp:107123:8: warning: unused variable ‘gconst69’ [-Wunused-variable]
107123 | IkReal gconst69=((3.14159265358979)+(((-1.0)*x15679)));
       |        ^~~~~~~~
ur3e/ur3e_ikfast61.cpp:107086:8: warning: unused variable ‘gconst69’ [-Wunused-variable]
107086 | IkReal gconst69=((3.14159265358979)+(((-1.0)*(x15675.value))));
       |        ^~~~~~~~
ur3e/ikfast_wrapper.cpp: In member function ‘std::vector<float> robots::Kinematics::forward(std::vector<float>)’:
ur3e/ikfast_wrapper.cpp:114:33: warning: comparison of integer expressions of different signedness: ‘std::vector<float>::size_type’ {aka ‘long unsigned int’} and ‘int’ [-Wsign-compare]
  114 |         if( joint_config.size() != num_of_joints ) {
      |             ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
ur3e/ikfast_wrapper.cpp:121:33: warning: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Wsign-compare]
  121 |         for (unsigned int i=0; i<num_of_joints; i++)
      |                                ~^~~~~~~~~~~~~~
cc1plus: fatal error: ur3e_ikfast_wrapper.cpp: No such file or directory
compilation terminated.
error: command '/usr/bin/gcc' failed with exit code 1
[end of output]

note: This error originates from a subprocess, and is likely not a problem with

What is the name of the link or the joint which is used as end effector for the UR5 arm and is the frame of the "base_link" still used as reference frame?

Is there a way to use this library to find the joint angles for the closest end effector pose in the workspace compared to a target end effector pose?

hello！I use this package but i can not find the package named ur_control

The links provided for .cpp file generation (using universal robot ur_description urdf) is generating error. Can u share the urdf file ? In your ur5 folder the urdf or dae is not shared.

I skipped the moveit_ikfast round off to 5 decimal place.

Did you also use ur5.xml format (from https://github.com/andyzeng/ikfastpy) to generate ikfast61.cpp file ?

Hi @cambel,

I noticed today that the FK of the zero-joint configuration does not seem to match the frame of the base on the ur controller.

On the ur controller, the pose of the zero-configuration for the joints has a negative X and Y value when expressed in the base frame (Y along the power cable, z up).

However, the following script

    zero_joint_pose = URKinematics("ur3").forward(np.zeros(6))
    print(zero_joint_pose)

returns [ 0.4569 0.19425 0.06655 0.70710678 0.70710678 -0. -0. ]

Am I doing something wrong or is a transform required to use the IK on a real robot?

Thank you for your work.
we want to use your code to creat the solutions for ur5. But we get different solutions when we calculate the rotation matrixs between from ROS and your code.
for examp,we get the rotation matrixs from quaternion in ros:
[ 9.44e-05 1 9.762e-05 -1.0915e-01
-1.56e-04 9.76e-05 -9.999e-01 6.04687e-01
-1 9.440e-05 1.5637e-04 4.318e-01 ]

but your code from jiont angle is :
rotation matrixs:
[ 1 9.746e-05 -9.446e-5 -1.0915e-01
9.76e-05 -9.999e-01 1.56e-04 6.04687e-01

• 9.440e-05 -1.56e-04 -1 4.318e-01]

We can see the two rotation matrixs have same position information，but the rotation part seem to be in other coordinate system