Title: Application of a dynamic pressure-sinkage relationship for lightweight mobile robots

Authors: Rishad A. Irani; Robert J. Bauer; Andrew Warkentin

Addresses: Department of Mechanical Engineering, Dalhousie University, Halifax, Nova Scotia B3J 1Z1, Canada ' Department of Mechanical Engineering, Dalhousie University, Halifax, Nova Scotia B3J 1Z1, Canada ' Department of Mechanical Engineering, Dalhousie University, Halifax, Nova Scotia B3J 1Z1, Canada

Abstract: This paper investigates a dynamic pressure-sinkage relationship which can be used in a wheel-soil model to better capture periodic variations observed in sinkage, drawbar pull and normal force as a rigid wheel interacts with loose sandy soil. The dynamic wheel-soil model can be used for wheels with or without grousers. Several case studies are presented to demonstrate the usefulness and applicability of this dynamic pressure-sinkage relationship. Hill climbing experiments were carried out using a smooth-wheel micro rover with a fixed suspension to confirm operational regions of the dynamic pressure-sinkage relationship. Single wheel testbed experiments were carried out to determine how well the model can predict changes in the number and length of the grousers on the wheel. It was concluded that dynamic pressure-sinkage relationship can predict the observed oscillations in the sinkage, drawbar pull and normal force with a single tuning case as the slip ratio and the configuration of the wheel changes.

Keywords: terramechanics; sandy soil modelling; grousers; pressure-sinkage relationship; rigid wheel; mobile robots; autonomous vehicle systems; lightweight robots; wheel-soil models; dynamic modelling; hill climbing; smooth-wheel micro rovers; sinkage; drawbar pull; normal force; slip ratio; wheel configuration.

DOI: 10.1504/IJVAS.2014.057838

International Journal of Vehicle Autonomous Systems, 2014 Vol.12 No.1, pp.1 - 23

Received: 19 Nov 2011
Accepted: 19 May 2012

Published online: 27 Oct 2014 *

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