My understanding is that you want to do it according to the method of the paper, right? The general process is as follows:

1, step module, establishment step 1, step 2 and step 3;

2. Interactive module, establishing contact under STEP 1. Specific types and parameters can be tried by yourself. (Suppose you have finished the MPC constraint, the MPC master node of two gears is located in the center of two gears, and only the master node is constrained below)

3. In the loading module, under the initial conditions, BC 1 fixed gear master node is established, and the rest keeps propagating.

In the initial state, BC2 is established to fix the main node of the pinion (6 degrees of freedom are 0).

STEP 1 no operation, the system establishes contact by itself;

Under STEP2, click the cell corresponding to BC2 and enter the rotation angle of the pinion (for example, enter 1 after UR3, and forget that it is an angle value with appropriate radian, so you can determine it yourself);

Under Step 3, click the cell corresponding to BC2 and uncheck UR3. (This step is too sure. Is it the release mentioned in that paper? You can try it yourself. )