Hey guys, I am simulating a dynami

[GMC11]

Hey guys,
I am simulating a dynamic robot movement on ADAMS 2020 and I want to record normal forces between driving wheels and the ground but I am encountering very high oscillations (shown in attached screenshot) in certain times of the simulation when I enter the post-processor. I tried increasing/decreasing damping coefficient of the contact force and I also checked that the wheel is not bouncing on the ground (y-displacement shown in attached screenshot) but still the high oscillations remained.
Any idea why and how to fix that?
Thanks in advance.

 

[GregLocock]

If the force is going to zero then the wheel is coming off the ground. So your y plot is misleading you, or your wheel has an unladen radius of 79.2.

Run the first second only so we can see what is happening.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[GregLocock]

Just thinking about it, if the wheel moves 1mm vertically in response to a force of 7000N there is no compliance there to damp.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[GMC11]

First of all thanks Greg for the quick reply.
Attached is the post-processor results for 1 second time. And can you please elaborate more on the idea of "no compliance there to damp"?

 

[GregLocock]

So, you are dropping the robot from 80 mm, the wheel makes contact, and compresses by 0.8 mm, with a force of 7000 N. Therefore its compliance is of the order of that of a steel disc not a tire. Damping that compliance won't work, the velocities will be too small.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?