Getting started with arm26

[Aaron Suberbiola]

Hello everyone.

I have been trying to understand how the arm26 model works, but I am having some troubles and I would like to ask you about them.

I have loaded the model and a motion file found in the documentation. I would like to know the muscle activation values so I can recreate that movement in the arm. I have tried with both CMC and Inverse Dynamics, but I can not do it. I have noticed that, when I load the motion file found, the muscles stay in red, like they were not activated, but when I use the motion file I get after working inverse dynamics, muscles stay in blue buyt they do not recreate the same movement.

Thank you very much.

[jimmy d]

Hi Aaron,

The motion files only store information on coordinate values (generally degrees or radians). If you load a .mot file you will only see the motion of the coordinates. This is not muscle driven. You will not get muscles changing color during Inverse Kinematics or Inverse Dynamics because neither are muscle driven and therefor the muscles have no activation.

Try using the CMC setup file found in the Arm26 output references folder. You will be able to complete a CMC simulation with the IK mot file being an input. The states file output from the the CMC simulation will contain the muscle activations used to generate the motion. Loading this states file into the GUI, you will see the muscle color change (as the muscle states are contained in the file).

Hope that helps,
-james

[Jan Thomas]

Hi all,
Is it possible to generate muscle driven motion using forward simulation
I am trying to run forward dynamics for leg69 (swing). I have used the ik_swing.mot file. What are the controls and the input I need to specify in terms of the file for example .sto or .xml file. Also, can I see the color change
in the case (i. e change in the activation level) where I use the edited muscle excitation? Thanks!

[jimmy d]

Run through the Tug-of-War example. It deals with setting controls: