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Passive Devices (Spring Parameters)

Posted: Mon Jan 14, 2019 5:06 am
by danieliordanov
Hello,

I am trying to add a passive aid walking device to a model to simulate the influence of the ankle device on gait and muscles involved in it (mainly gastrocnemius).
I am performing several trials with different parameters of stiffness, damping and transition but I do not understand the values of TRANSITION at all.

In a previous walkthrough I found the following explanation for TRANSITION: This term indicates the transition from zero to constant stifness as the coordinate exceeds its limit, in degrees.

Does it mean that transition * limit(degrees) = stiffness? I do not understand why in this case the value of TRANSITION is 2.0 meanwhile the values of the other parameteres are:
upper siffness: 30.0
upper limit: 5.0 degrees
damping: 0.01

Can anyone explain me the values for TRANSITION and the effect on passive device simulation?
Thank you in advance

Re: Passive Devices (Spring Parameters)

Posted: Wed Jan 16, 2019 2:04 am
by mitkof6
In this case, you can have a look at the implementation to understand how the model works:

https://github.com/opensim-org/opensim- ... e.cpp#L259