InverseDynamics error

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Evgeniya Tomskaya
Posts: 9
Joined: Mon Sep 26, 2016 5:02 am

InverseDynamics error

Post by Evgeniya Tomskaya » Tue Nov 15, 2016 5:14 am

Hi!
I have a problem - Opensim takes off without explanation most often after I`ve done Forward Dynamics, but sometimes even during a session. What problems may be here and how to correct them?

And another question is about RRA. I am trying to use this tool for my model, but OpenSim show me this error: "InverseDynamics: ERROR- overconstrained system -- need at least as many forces as there are degrees of freedom." I don`t understand where and what I must correct to bypass this error, help me please with your advice!

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Dimitar Stanev
Posts: 1096
Joined: Fri Jan 31, 2014 5:14 am

Re: InverseDynamics error

Post by Dimitar Stanev » Wed Nov 16, 2016 6:43 am

I have a problem - Opensim takes off without explanation most often after I`ve done Forward Dynamics, but sometimes even during a session. What problems may be here and how to correct them?
If you run the model in FD manner, you need to supply the external forces and the muscle controls. If you don't supply them the model will fall due to gravity.
And another question is about RRA. I am trying to use this tool for my model, but OpenSim show me this error: "InverseDynamics: ERROR- overconstrained system -- need at least as many forces as there are degrees of freedom." I don`t understand where and what I must correct to bypass this error, help me please with your advice!
The error means that you have less actuators than degrees of freedom, thus some joints are not actuated. I suppose in your reserve actuator file, you have forgotten to add an actuator for some coordinate.

Best

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