Why the Disk Friction Clutch of Simdriveline always generate a mutational torque while synchronize?

simulink/simdriveline is very skilled to build the model of vehicle transmission, however, I encounter a troublesome problem the "Disk Friction Clutch". The clutch will always generates a mutational torque that I can not understand when driving disc synchronize with driven disc, my simulation result is as follows:

I also submit my model that is shown in annex.

I am so appreciate and longing for that a friend can help me with this problem or give me some advises.

Answer 1

[Fred]

This may be related to the internal modelling of the "disk friction clutch" block. In other words, it's of some "simulation error", and should not be interpreted as accurate theoretical results.