# The meaning of AnyGeneralMuscle output value

Hi

I used AnyGeneralMuscle to connect human and Exo. Among the six values output by AnyGeneralMuscle, I found that the curve trends of moment_x_sum and moment_y_sum are the same. Could you tell me how the x, y, and z-axis moments in AnyGeneralMuscle are calculated? Thank you in advance.

Best regards
BBJ

Hi BBJ,

Sorry for the slow reply this post was accidentally overlooked.

Please be a little more specific, which model and which variable are you referring to?

The AnyGeneralMuscle is like any other muscles except for one difference which is that it can be allowed to create a pushing force. This is controlled by the ForceDirection property which by default is -1 (pull) and 1 (push).

The muscles are part of the muscle recruitment problem like any muscle in the model, it is not uncommon to see many muscles follow the same trends, but this naturally depends on the model.

Best regards
Søren

Hi Søren

Thank you very much for replying to my question. My model is a normal walking process of a human wearing the exoskeleton. I used AnyGeneralMuscle to connect human and Exo. The reference of AnyGeneralMuscle and the interaction force at the thigh are as follows. 2.5 is the initial heel contact.

I don’t know if the calculated interaction force is normal. I found that the three moment curves calculated by AnyGeneralMuscle are very similar. What is the reason? Could you tell how these moments are calculated? Thanks again.

Best regards
BBJ

Hi BBJ,

If the three curves for the moment are rather similar it means that the direction of the resultant torque lies not dominantly along either x y or z but in a direction which "points equally" in all directions.... On your graphs the x and y are rather similar meaning that the direction moment projected into the xy plane is in 45 deg. (hope it makes sense, it is a little difficult to describe in words.)

Concerning how it has been calculated please see e.g. this paper:

2006 Damsgaard M, Rasmussen J, Christensen ST, Surma E, de Zee M (2006), " Analysis of musculoskeletal systems in the AnyBody Modeling System ", Simulation Modelling Practice and Theory, vol. 14, pp. 1100-1111. [DOI, WWW]

The general muscles are part of the muscle recruitment algorithm described in this paper.

Best regards
Søren

Hi Søren

Thank you for your reply. I want to know whether the value of these moments is related to the value of the force? Are the moments in the x, y, and z directions calculated from the forces in the x, y, and z directions? Thank you very much.

Best regards
BBJ

Hi BBJ,

No the moments are calculate separately from the forces, there is a separate muscle actuator of each of the DOF's .

Best regards
Søren

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