The Single-Track Three Legged Mobile Robot

Abstract

The Single-Track Three Legged Mobile Robot achieves the form and function of a motorcycle but with the added benefit of legs and partial or fully automatic stability of balance. The robot comprises a body and three articulated legs arranged one behind the other in a narrow profile to walk and maneuver along narrow trails and paths, by placing successive footfalls in a generally single-track or in-line fashion. It achieves stability of balance without motion by positioning the three legs in a tripod stance. It maintains (or regains) stability of balance during locomotion through controlled foot placement and repeating intervals of a bipedal or tripod stance. It executes a single-track turn by leaning the body into the turn, using gravitational forces to counteract the outward centripetal force. The proposed gait strategy keeps two legs on the ground at all times, simplifying balance control to the roll direction. The control system comprises feedback sensors, digital computer, and software for foot position planning. This paper presents the robot design, various three-legged gaits, control method and architecture, experimental results from a digital simulation, and a proof-of-concept prototype.