How to decide SimDriveline Dryclutch parameters values?

Hi! I am modelling a five speed manual transmission with dry clutch to simulate an AMT and test the control/shift logic. When I bring the blocks together by adding double-sided synchronizers, inertias, disk friction clutch ( to simulate main dry clutch), and a full vehicle body. I have engine speed and corresponding acceleration pedal position. I am rotating the shaft with rotational velocity source.

The problem is, I could not get the point about the parameters of disk friction clutch. If I use default values it gives incorrect output graph. When I delete one zero from piston area and velocity tolerance parameters, it seems to work correct. But what are the actual meaning of those parameters? I have already red the help file. Additionally, how to decide how much pressure to be applied to the clutch? When I increase the pressure value, clutch follower shaft velocity decreases. How should I decide those parameters and pressure values? How will I know if clutch is locked or unlocked? To determine clutch state, I just took the difference of base and follower shafts speed and compared with the velocity tolerance value whether it is greater or smaller than that difference. Is it right or wrong?

Regards,

Answer 1

[Swarooph]

Hello Arden,

AFAIK the clutch state is not determined as simple as that. Refer to the section 'Clutch States' in the fundamental friction block documentation here which explains the conditions:

http://www.mathworks.com/help/physmod/sdl/ref/fundamentalfrictionclutch.html

The Disk Friction block uses the Fundamental Friction block underneath so the states are the same. Also, consider enabling filtering for the input to the clutch. If you are using an S-->PS block, you can do this as explained in 'Input Handling' section in the documentation here:

http://www.mathworks.com/help/physmod/simscape/ref/simulinkpsconverter.html

Otherwise insert a transfer function of a low pass filter.

[Arden Kuyumcu]

Hi, thanks for your reply. As I explained above, I compare the slip velocity with the velocity tolerance. And I am already using a filter to to smooth the pressure application.

The main problem is what value should I use for the piston area, velocity tolerance and pressure threshold. When I increase piston are from 0.001 to 0.01 it works but it don't when it is 0.001. Additionally, I set the pressure threshold to 1 Pa and I am applying 10 bar to the clutch to engage and lock it. if I set 100 or 1 Bar it does not work as intended.

Thanks,