closed loop kinematic chain Problem

Discussion in 'Modeling' started by HazemAzldin, Jul 1, 2020.

  1. I am trying to convert a URDF file to an MJCF file but the problem when I use the MuJoCo ./compile program I get the error:
    XML Error: URDF body has multiple parents:
    Element 'joint', line 199, column 3

    The robot uses a prismatic and revolute joint. So it has to be attached to multiple parents. there is a thread answering a similar problem but I didn't understand what is the meaning of equality constraints and how can I add them manually. can anyone please clarify more about the equality constraints and I would be thankful if there any examples of solving the closed-loop kinematic chain problem.