If the GRFs and CoP data are with respect to the treadmill's forceplate reference frame (angled) then you need only define a PhysicalFrame (either a treadmill Body or PhysicalOffsetFrame affixed to ground). In specifying the ExternalLoads editor change the "Force Expressed in" and "Point Expressed i...

Your approach sounds reasonable and you can apply any force (either a profile you create or the experimental GRF) to any body in the model. Once you've created the model you can apply the force using External Loads tab in the GUI and associate forces (with force vector and point locations as columns...

> Why are the extensor forces so high? Perhaps because generating flexion moments at the elbow requires: 1) bi-articular biceps which flex both shoulder and elbow and 2) even uni-articular elbow flexors will induce shoulder flexion acceleration. In reality, there are numerous other muscles that cros...

The reaction reported is the total reaction force and moment on the calcaneous body as applied to its body frame. You can use it to compute the center of pressure and free-moment.

Sorry for the confusion. OpenSim, before its full integration of Simbody (before 2.0), used to solve for the generalized forces that generated the user-supplied acceleration, iteratively. Since then, all multibody dynamics are performed with Simbody. The InverseDynamicsSolver provides a simpler inte...

I am not sure this is the issue in your case, but be aware that you cannot realizedDynamics within computeControls of a Controller. That will cause an infinite recursion because realizeDynamics invokes the Controller::computeControls on all Model controllers. Actuators then access the computed contr...

Adam, Remember that the constraint reaction forces are presented in the body frames (e.g. calcaneous and/or ground) and are not resolved at the point of contact. If your resolve the moments to the effective center-of-pressure (CoP) on the floor plane that will enable you to verify the CoP and valida...

If you haven't already, try previewing your ground reaction forces in the GUI and double check the units for the GRF data. If, for example, your center-of-pressure (COP) is in mm vs. m, or force-plate moments are reported in N*mm your computed moments will be enormous (like what you are seeing). If ...

Either the inertia, constraints, or applied forces are different if you are using the same input kinematics. The distal joint moments would be similar if the distal inertia (outboard from the joint) are similar. The large proximal moments likely means ID has to account for large forces that are assi...

It should not be necessary to run the exoskeleton and human models separately. You can pose your model with the exoskeleton on and perform short forward dynamic simulations with the ForceReporter (Analysis) attached. Do the forces from the device look reasonable? CMC will fail if it cannot generate ...