Postural Control of Standing Posture With Robust Nonlinear Compensator in the Presence of Delayed Feedback

Postural regulation and stability is a complex neuromuscular task and it requires coordination among different limbs and body parts for successful execution. The central nervous system (CNS) successfully controls this task. The proprioceptors provide feedback of fascicle length and fascicle velocity from joints to CNS which then regulates the motion. The muscle feedback by proprioceptors i.e. Muscle-Spindle (MS) and Golgi-Tendon-Organs (GTO) have neural transmission latencies that make control of CNS activity and computations an intricate issue to handle. This article discusses a robust nonlinear compensator design relying on vector filed method (feedback-linearization) in the presence of physiological delays for postural stability of a single link biomechanical model. We included small and medium delays in MS sensory feedback. We designed and implemented H∞ dynamic controller with feedback linearization to measure the joint torque or output to maintain postural stability. The joint torque makes up for the latencies and settles the movement profiles inside anatomical imperatives and demonstrates the applicability of feedback linearization with H∞ compensator in the presence of physiological latencies.