Pinbot: A Walking Robot with Locking Pin Arrays for Passive Adaptability to Rough Terrains

Abstract

To date, many control strategies for legged robots have been proposed for stable locomotion over rough and unstructured terrains. However, these approaches require sensing information throughout locomotion, which may be noisy or unavailable at times. An alternative solution to rough terrain locomotion is a legged robot design that can passively adapt to the variations in the terrain without requiring knowledge of them. This paper presents one such solution in the design of a walking robot that employs pin array mechanisms to passively adapt to rough terrains. The pins are passively dropped over the terrain to conform to its variations and then locked to provide a statically stable stance. Locomotion is achieved with parallel four-bar linkages that swing forward the platforms in an alternating manner. Experimental evaluation of the robot demonstrates that the pin arrays enable legged locomotion over rough terrains under open-loop control.