I have acquired motion-capture data at the head, arms, and torso of an individual seated and exposed to random vibration. I also have the vibration of the seat. I’m trying to determine how to implement this in the seated model. Any insights will be welcomed.
Also, I’m trying to understand the following post. What exactly does it mean to “In AnyBody, the model will respond to each little vibration no matter how fast it is.”
I think I wrote that remark several years ago. Let me explain a little better. Muscles can respond to external forces. Imagine you are sitting in a seat that slowly rocks from one side to the other, such that the seat changes direction wrt. the vector of gravity. In this case, the muscles must slowly change their actions to maintain the posture against the changing direction of gravity.
If we make the rocking faster, then the reconfiguration of muscle forces also becomes faster, until the changes become faster than the electro-chemical force production processes in the muscles can follow. The typical body reaction is to replace the constant adjustment of muscle forces with a static co-contraction. The system now changes from being actively regulated to being a passive mass-spring-damper system. AnyBody does not predict this transition, and it cannot perform the forward dynamics analysis necessary to predict how the mass-spring-damper system will move.
I hope that clarifies the point.
Best regards,
John