Ringbot Quad: A Monocycle Robot with Four Legs for Versatile Wheel-Leg Transformable Locomotion

Abstract

Integrating multiple locomotion modes on a single platform has become an active focus in pursuit of versatile and efficient movement. This paper introduces a novel monocycle robot with four legs, named Ringbot Quad, combining the wheeled and legged mechanisms. The Ringbot Quad is developed as a unique monocycle mechanism that replaces the traditional monocycle drivetrain with four individually actuated driving modules, each topped with an articulated leg. The four legs can be used for balance and steering in driving mode and for quadruped walking that fully supports the body with the legs. By switching between two distinct locomotion modes, it can navigate various terrains and overcome obstacles typically challenging for either mechanism alone. In this work, we present a compact-scale Ringbot Quad prototype as a proof of concept for the proposed mechanism, demonstrating the feasibility of a new type of mobile robot.