The Affect of Multi-source Time Delay to the Human Balance Based on Robust Control Model

Time-delay is a prevalent phenomenon in human body during standing and locomotion, and it is one of the main factors to affect human balance ability. The purpose of this study is to design a human balance control model, and to analyze the human possible posture control mechanism with multi-source delay considered. Based on an inverted pendulum with the ankle joint model, we derived and proved that the human body existed multi-source time delay, and then designed a robust state feedback controller with an observer for the generalized system, which is with delay state and delay control inputs in continuous time. This controller can be considered as the central nervous system (CNS) for the human balance controller mathematical model. Finally, applying simulation software, we obtained the balance regulation kinematics responses to anterior and posterior (A/P) surface translations, and discussed the effect on the dynamic response of the human body to different kinds of the time-delay. The robust controller can stable the human system within larger interference and larger time-delay. This paper provides a useful method for analyzing the impact of the multi-source time delay on the human balance system.