Study of Self-synchronizing Biped Robot

Abstract

Low energy biped walking style is proposed, where self synchronized mechanical motion is continuously stabilized by some actuations triggered by sensing signal. Self synchronizing sideways motion is based on a two point support inverse pendulum, where stepping cycle time is controlled by a small variation of actuation. Contrarily, self synchronizing forward leg swing is based on a pendulum, where maximum forward angle is produced in a half cycle time of natural swing frequency. Two experimental robots of air-cylinder plus DD motor model and 7-servo motor model are developed. The former one makes kicking motion to make a sideways undulation triggered by a signal of gyroscope, and makes leg swing actuated by a direct-drive motor on a center of hip joint. The latter makes posture change triggered by gyroscope to get gravity energy to keep sideways undulation, and simultaneously, makes leg swing actuated by low gain position control of hip joints. The performance of these robots are demonstrated by experiments.