Using CMC to track pedal forces

[Colin Smith]

I am hoping to use CMC to track both kinematics and pedal forces for a pedaling simulation. I know the method was originally capable of tracking pedal forces (i.e. the example in Generating Dynamic Simulations of Movement Using Computed Muscle Control, Thelen 2003), but it appears to only track kinematics in Open Sim. Is it possible to use the CMC in Open Sim to track the pedal forces as well?

Thanks,
Colin

[Ajay Seth]

The implementation in OpenSim more closely supports the application of CMC for gait (Thelen and Anderson, J Biomech. 2006;39(6):1107-15) where experimentally measured external forces are applied directly to the model. Is there additional information you need from tracking that you could not acquire from the model by applying the forces you measured? Subsequently, you could constrain the foot to the pedal, via a WeldConstraint and compare the constraint reaction forces to the experiment after applying the controls computed from CMC (which was unconstrained but with the experimental forces applied). This would at least test if you could generate a forward model that does not rely on experimental forces but generates similar forces.

[Colin Smith]

Thanks Ajay, I hadn't thought of double checking the results in that manner.