Clamping coordinates during forward dynamic simulations

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Peter Bishop
Posts: 21
Joined: Thu Aug 28, 2014 10:47 pm

Clamping coordinates during forward dynamic simulations

Post by Peter Bishop » Mon Jul 02, 2018 12:03 pm

Hello,
I've been trying to run forward dynamic simulations (both from the GUI and the API via MATLAB) and find that some of my model's coordinates go beyond their specified range of motion during the simulations. To stop this I've tried clamping the coordinates, but this does not seem to work - the simulations ignore the clamped bounds and the coordinates go outside of their specified ranges anyway. (I don't have this problem if I lock the coordinates, however; locked coordinates stay immobilised during the simulations.)

Any thoughts on what I might be missing would be greatly appreciated. Thanks!

Peter Bishop.

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jimmy d
Posts: 1375
Joined: Thu Oct 04, 2007 11:51 pm

Re: Clamping coordinates during forward dynamic simulations

Post by jimmy d » Mon Jul 02, 2018 12:14 pm

The range of motion and clamping are only for kinematic analyses (IK). In a Forward simulation, you need to define forces, and there would have to be some way of determining the forces that these 'hard-stops' (joint limits or clamps) would generate.

Instead, you will have to add something like a CoordinateLimitForce() of maybe a constraint to your model.

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