Unable to get the joint pos limits in python

GiulioRomualdi commented 1 month ago

I wrote the following code to get the joint position limits in python

def get_joint_limits(kindyn: idyn.KinDynComputations, joint_list: List[str]):
    if not kindyn.isValid():
        raise RuntimeError("The KinDynComputations object is not valid")

    lower_limits = np.array([-np.pi] * len(joint_list))
    upper_limits = np.array([np.pi] * len(joint_list))

    for i in range(kindyn.model().getNrOfJoints()):
        joint = kindyn.model().getJoint(i)

        if not joint.hasPosLimits():
            continue

        for dof in range(joint.getNrOfDOFs()):
            upper_lim = 0.0
            lower_lim = 0.0

            if not joint.getPosLimits(dof, lower_lim, upper_lim):
                continue

            upper_limits[joint.getDOFsOffset() + dof] = upper_lim
            lower_limits[joint.getDOFsOffset() + dof] = lower_lim

    return lower_limits, upper_limits

however when I called I got the following error

File "/home/gromualdi/robot-code/element_rl-for-locomotion/code/ergocub_amp_walking/config/robots/ergoCubGazeboV1_1/../../../script/amp_walking.py", line 125, in get_joint_limits
    if not joint.getPosLimits(dof, lower_lim, upper_lim):
  File "/home/gromualdi/robot-code/robotology-superbuild/build/install/lib/python3/dist-packages/idyntree/swig.py", line 3625, in getPosLimits
    return _iDynTree.IJoint_getPosLimits(self, _index, min, max)
TypeError: in method 'IJoint_getPosLimits', argument 3 of type 'double &'

cc @traversaro @Giulero

traversaro commented 1 month ago

getPosLimits and other methods that uses primitive types passed via reference as outputs can't be easily wrapped in Python or MATLAB, probably we should suppress them to avoid that they appear in SWIG bindings at all. As an alternative, you can use getMinPosLimit() and getMaxPosLimit methods.

traversaro commented 1 month ago

See for example:

GiulioRomualdi commented 1 month ago

Thank you, @traversaro! The methods you suggested work fine!

GiulioRomualdi commented 1 week ago

I think we can close this issue

robotology / idyntree

Unable to get the joint pos limits in python #1187