Stance postural control of a musculoskeletal model able to compensate neurological time delay

Neurological time delay is one of the important elements threatening human postural stability. Previous studies mainly focused on the neural controller to stabilize a human size inverted pendulum model. What kind of postural control mechanism is necessary for compensating neurological time delay by controlling muscles still remains a question. This research proposed to investigate whether a stance control model with constant feed-forward control input to muscles will enable the musculoskeletal model to stand when neurological time delay exists. A musculoskeletal model with 70 muscular-tendon actuators was used to represent the human body. We hypothesized that stance postural control model consists of both feedback and feed-forward control. And the latter one is a pre-added constant control input, necessary to keep musculoskeletal model standing when there is no neurological time delay, to the muscles for compensating neurological time delay. We calculated feed-forward controls and found the longest neurological time delay it could compensate. As a result, we succeeded in keeping a musculoskeletal model standing when neurological time delay was 65ms at most, where transmission time delay was 45ms and activation dynamics time delay was 20ms.