Hi all!
I want to simulate the effect of a passive, upper arm exoskeleton. At the end my, goal would be to compare the physical device with the simulated one, right now I want to help the current building process.
For that I would like to move my OpenSim model based on recorded data and somehow examine the effect of the exoskeleton. I would like to have an active interaction with the exoskeleton (so I would like to change properties of it, add pull/loosen force during runtime).
I already recorded and processed motion data, and also built my exoskeleton model from ClutchedPathSpring-s in OpenSim API (Matlab) and I tested them during simulations too.
These simulations are a modified version of the Hopper Device. To have an interactive part in the simulation as well, I created a for cycle with small time steps and I run the simulation with the Manager() class, every time modifying the actual values of the actuators, when needed (in other cases the simulation takes the previous state and just goes on). These parts are kinda working (I was able to move the upper arm model - containing only bones and the actuators - with the actuators). My problem is, that I'm not able to move the model based on the recorded data, using the muscles. I tried to use controllers (as in the case of the actuators, when I change the controlfunction value between 0-1) and I also tried out some functions of the muscles (like setActivation, setActuation), but none of them seems to be causing movement during the simulation. (The only thing, what I experience, is a damping movement - wherever I move the arm, it starts to move down and up, with a slow damping. I set the gravitation to zero, and I also examined really long this movement. It is not stopping at a "down" state, but somewhere in the middle - and I can't figure it out, what it is. Near to that movement, any trial, where I wanted to change the movement of the arm, was unsuccessful.)
Where could be the problem, what could be the solution? I'm really opened to any suggestion!