Model-based development of a compliant locomotion system for a small scout rover

Abstract

All currently active planetary exploration robots employ wheels for locomotion. In this work an alternative robotic locomotion concept is examined: the rimless wheel, also known as whegs. It has been proven to be successful in traversing rough terrain on earth and inhibits an appealing simplicity in its mechanics and controls. These aspects along with its inherent redundancy make the rimless wheel particularly suited for planetary exploration. The rimless wheel’s kinematics and compliant spokes are analytically examined using mechanical models. The dynamics of these models are explored in a computational multi-body simulation which confirms the conclusions drawn from the analytical models about running, climbing and movement on rough terrain. A parameter variation then yields a set of suitable parameters for a future scout rover. The application in sand is considered separately both analytically and computationally. Based on these results a single wheel is build and tested on the conclusions drawn from modelling and simulation. These experiments provide strong support that the two-sided goal of efficient movement on hard and flat surfaces as well as reliable negotiation of rough terrain can be achieved with the developed locomotion system.