From the mujoco_py generated wrapper: https://github.com/openai/mujoco-py/blob/master/mujoco_py/generated/wrappers.pxi We have these four functions: https://pastebin.com/ZvnVLnRM 1. What does the p suffix mean? 2. What does the r suffix mean? 3. What does the quantity xvelp represent?
jacp is 3-by-nv position jacobian. jacr is 3-by-nv rotation jacobian. xvelp = jacp * qvel is translation velocity in 3D Cartesian coordinates. Note that mujoco_py is developed by OpenAI and I am not supporting it because I know very little about it. So I can only tell you what the underlying mj_XXX() functions do.