Parallel Link-based Light-Weight Leg Design for Bipedal Robots

Abstract

A new leg design for bipedal walking robots that utilizes 6-dof parallel link mechanism is proposed. Reducing leg inertia is a crucial requirement for realizing agile walking and fall avoidance involving multiple stepping. The proposed parallel link design enables embedding all leg actuators in the torso and thereby significantly reducing the leg inertia. Some fundamental kinematic characteristics of the proposed leg mechanism including movable range and maximum static load is shown. A real small-sized humanoid robot equipped with the proposed leg mechanism is developed. Experimental results show that the proposed leg mechanism achieves high position tracking performance even at high frequencies, and that the robot is able to perform basic walking maneuvers with different strides and step durations.