Hi, I have already done the Inverse Dynamics simulation without the external force using the following command. tau = InverseDynamicsSolver.solve(ID_state, u_dot). Here I set u_dot as desired joint accelerations and state consisting of desired current joint position and velocity. I iterated the abov...

I think, I have understood what is required to be done for my problem.

If the muscle excitations are set using any prescibedController, Metabolic probe works correctly and give right numbers for metabolic cost and the obtained plot is very similar to that obtained from GUI.

Hello, I want to know how OpenSim applies the ground reaction forces for doing its inverse dynamics. For example in the following box, Capture.JPG . It is shown that force is applied to body 'calcn_r', and the point and force magnitude is expressed in the ground reference frame. So, is it point-to-p...

Hi Axel, My main objective was to see metabolic cost, so muscle activation being 0 or 0.01 was not going to have much effect on my results (in the range of 3-5 units may be). I can suggest you to check Millard2012AccelerationMuscle, as in its description I found that "it is possible to simulate 0 ac...

Thanks Thomas Uchida,

This paper is exactly what I wanted.
But it seems activations has to be taken, not excitation, along with the electromechanical delay, to compare with EMG data, as in paper. I'll go through it.

Ratna

Hello, Is there a way I can understand the similarity between EMG and muscle excitation? Muscle excitations, as explained in OpenSim, is a combination of motor recruitment and firing frequency, and through EMG also, I think, we record almost the same thing. So, can we assume both to be exactly same?...

Hi Dimitar, Okay, I'll try to calculate passive muscle force separately. I think using PassiveForceMultiplier * MaxIsometricForce in the API, passive muscle force of each muscle can be calculated. I added the extra load in the GUI, by defining a body of 1kg and negligible inertia (so that it can act...

Hi, Are passive muscle forces taken into consideration while doing inverse dynamics in OpenSim GUI? Here is the process I followed when I found a problem: 1. In the Arm26 model and using the given trajectory (of elbow flexion), I did inverse dynamics in OpenSim GUI and calculated the amount of torqu...

Thankyou Mike for your kind attention. Yeah I have realized the stage to the dynamics and I am able to obtain the metabolic cost, but the metabolic cost I am getting seems to be containing only two components of it. I mean, out of the Mechanical work rate, Shortening heat rate, Activation and mainte...

Hi, I imported an arm model MoBL Upper Extremity Dynamic Model in matlab which was successful and I was able to access all of its components. But when try to simulate it by applying force to its elbow joint with PathActuator using manager.integrate(), I start getting a constant error: "Error detecte...