The sinkage characteristics and prediction of a planetary rover based on a similarity model experiment

摘要

The environment on an extraterrestrial planet is complex, with soft surfaces and low gravity, which make it easy for rovers to sink and skid. Excessive sinkage may occur under large slip conditions of probe rovers and could influence the survey mission. Predicting the sinkage performance of wheels under slip conditions is important for the development and performance evaluation of exploration rovers. This paper presents a dimensional analysis on the main parameters of the wheel-soil interaction system; the analysis was performed based on the similarity law, for which corresponding similar scale values were obtained. Referring to the lunar surface gravity environment, we have produced a 1/2 scaling model rover. To investigate the sinkage characteristics of the model rover, tests were performed with different wheel loads (5 N, 7 N, and 9 N) and soil states (loose, natural, and compact). The characteristic parameters of a rear wheel rut were also analyzed, including rut depth (hereinafter referred to as apparent sinkage) and slip ratio (hereinafter referred to as apparent slip ratio). Experimental results were analyzed to evaluate the sinkage characteristics and to draw conclusions. Sinkage models for the rover under different soil states were proposed, and verification and error analyses for the sinkage models were conducted using indices such as the mean relative error and root mean squared error. The experimental results and conclusions are useful for optimal rover design and improvement/verification of wheel-soil interaction mechanics models.