Wrong joint state from Urdf Joint Revolute

[HainingLuo]

HI,

I have been using Unity Robotics Hub for my own robot. With the getPosition() function in for revolute joints, I realised the joint states I got were always close to zero. After checking the code in UrdfJointRevolute.cs, I found the following definition.

    public override float GetPosition()
    {
        #if UNITY_2020_1_OR_NEWER
            return ((ArticulationBody)unityJoint).jointPosition[xAxis] * Mathf.Deg2Rad;
        #else
            return -((HingeJoint)unityJoint).angle * Mathf.Deg2Rad;
        #endif
    }

The states are tranformed from degree to radian. Although I am not sure if this is the case for all versions, as least in version 2020.2.0b9, the position from (ArticulationBody)unityJoint).jointPosition[xAxis] is already in radian, so they are transformed twice and therefore always close to zero.

It would be greatly appreciated if any members can verify if this is indeed a bug! Thanks in advance.

[at669]

Hi @HenningLuo, thanks for catching this bug! We'll put in a fix for this issue.