Research On Wheel Soil Interaction Mechanics For Planetary Exploration Rovers Under Cornering And Slip Conditions

With the gradual development of the deep space exploration,planetary exploration rovers move autonomously on the surface of planet carrying various scientific instruments.Running on rugged planet surface is a big challenge for the planetary exploration rover beacause the characteristics of the planet surface may lead to the movement failure of the wheel,such as longitudinal slip,longitudinal skid and lateral skid.The lateral skid of the wheel will bring great difficulties to the movement and navigation control of the rover,which may lead to the failure of the planetary exploration mission,but few relatively studies have been done.Therefore,the study of the lateral skid terramechanics is essential and urgently needed.Experiment is the most direct and effective means to study terramechanics.After analyzing the state of the wheel-soil interaction,it is divided into three types: pure longitudinal slip condition,pure longitudinal skid condition,pure cornering condition,combined cornering and slip condition and combined cornering and skid condition,and the relationship between each other is clarified.A series of experiments were carried out to study the influence of wheel running state parameters on the wheel-soil interaction terramechanics,which is the basis of theoretical analysis,model derivation and soil parameters identification.The wheel-soil interaction model is the foundation of the application of terramechanics.Based on experiments,the analysis of the traditional wheel-soil interaction model,and the redefined wheel slip and skid characterization,wheel sinkage and wheel-lug effect are analyzed.According to the above results,the wheel-soil interaction model under combined cornering and slip condition is established and its prediction performance is evaluated.After analyzing the coupled degree of the integral wheel-soil interaction model,a soil parameter identification method is presented.The integral models are simplified and the closed-form analytical decoupled models are deduced by means of the method of stress distribution linearization.Based on the closed-form analytical decoupled models,a method for real-time soil parameter identification is developed.In summary,according to the experiment results,the integral wheel-soil interaction model and the closed-form analytical decoupled model are established,which can be used in pure longitudinal slip condition,pure cornering condition and combined cornering and slip condition.Two soil parameter identification methods are developed for the integral and closed-form analytical decoupled model.