how to change the equality constraint during simulation

[yinzikang]

Hi, I am trying to simulate the robot without a gripper opening a door with python-version Mujoco in the following fig.

As you can see, the robot does not contact the door now. So first I need to move the robot and make it contact the door handle.
Then I can add a 'connect' type equality constraint to make the robot and door move together.

So the question is: is it possible to change the constraint during the simulation? Or I must make the robot contact the door when loading the XML file, which is troublesome to calculate and adjust the init qpos of the robot.

Any advice is welcomed

[yuvaltassa]

See #229

[yinzikang]

Your solution is wonderful and works well in my model.
Thanks a lot.