Controlling the Walking Period of a Pneumatic Muscle Walker

In this paper, we investigate the limit cycle of a biped walker driven by pairs of pneumatic artificial muscles. We show, experimentally, that the period of the limit cycle changes when different control parameters are applied and estimate the relationship between the period and the parameters through trials. A step-by-step feedback controller is proposed to stabilize walking based on the estimated relation. The stability of the feedback controller is demonstrated by showing that the biped can walk down a stair. KEY WORDS—biped walking, pneumatic actuator, artificial muscle, limit cycle