Multiple-Input-Multiple-Output closed-loop balance control system. The body mechanics represent the dynamics of a double-inverted pendulum with the corrective ankle and hip torques as inputs and the joint angles as outputs. The stabilizing mechanisms represent the dynamics of the combination of active and passive feedback pathways of the concerned body(part) and generates a torque to correct for the deviation of upright stance. The balance control model can be perturbed with support surface movements (Sx), perturbation forces at the hip (Fp1) or at the shoulder (Fp2). Positive torques and positive angles are defined as counterclockwise.
Boonstra et al. Journal of NeuroEngineering and Rehabilitation 2013 10:23 doi:10.1186/1743-0003-10-23