Theoretical Analysis and Experimental Research on Wheel Lug Effect of Lunar Rover

Abstract

Wheel-soil interaction terramechanics is of great significance for the research of planetary rovers,yet the current research on wheel lug effect is insufficient.Based on the Rankine passive soil pressure theory,the two work modes of lugs are analyzed,formula for calculating the lug height and number to form continuous shearing soil loop,as well as that for determining inclination angle are deduced.Experiments were performed using wheel-soil interaction system and two wheels with height of 165mm,radius of 157.35mm and 135mm,respectively.The lug heigh,lug number and inclination angle were changed.Experimental data verified the theoretical results and some useful conclusions were obtained:increasing lug height can improve the traction performance,for example,the wheel with lugs of 15mm in height increased the drawbar pull by 60%;increasing the number of lugs can be helpful for forming continuous shearing loop;the inclination of lugs can decrease the vibration amplitude of wheel;the drawbar pull increases with the slip ratio,but it is better to control it under 0.4.The researching results of this paper provide theory for lug design and force prediction,which can also be used for the similar Mars rover and terrestrial vehicle.