Dynamic control of bipeds using ankle and hip strategies

In this paper, we propose a new way to solve the dynamic control under unknown perturbations which takes into account the postural movement notion. For that, a multi-chain mechanical model of a human body and a general control architecture are proposed. The main originality lies in the use of ankle and hip strategies postural movement notion (physiological notion) to ensure the biped dynamic equilibrium. The principle is based on behavioral rules using limiting conditions and "equilibrium classes". This notion is introduced at the "coordinator level" of our architecture and called the AHS (Ankle and Hip Strategy). It contributes to maintain the equilibrium even in the presence of a rough perturbation acting on the minimization of the roll and pitch angles in function of the task constraints and choosing in real time the strategy to adopt. Finally, we illustrate the whole strategy through an hip strategy example related to the standing posture under perturbations.