基于地面力学的月球车爬坡轮—地相互作用模型

Lunar Rover Wheel-Terrain Interaction Model for Climbing-up-Slope Based on Terramechanics

  • 摘要: 月球车爬坡地面力学模型在月球车的设计、越障性能评价、控制和仿真等方面具有极其重要作用.利用月球车轮地相互作用测试系统进行车轮爬坡性能实验,结合实验数据在传统车轮—土壤相互作用应力分布模型之上推导出爬坡轮—地相互作用模型,同时考虑爬坡角度对浅层月壤应力分布的影响,提出了随滑转率变化的沉陷因数经验公式,来反映月壤压实、刮带、侧向流动等引起的滑转沉陷.通过对应力分布公式进行积分转化得到集中力/力矩计算模型,利用ADAMS二次开发的柔性爬坡仿真环境并结合实验数据进行模型验证.在斜坡角度为16°,载荷为100N,当滑转率从0增加到0.6时,将模型的车轮斜坡法向载荷、挂钩牵引力和驱动力矩的计算值与实验数据相对比,结果相对误差不超过10%,因而该爬坡模型可以有效地用于月球车轮地相互作用的力学计算.

     

    Abstract: The lunar rover terramechanics model for climbing-up-slope plays important roles in mechanical design,obstacle-overcoming performance evaluation,control,simulation,etc.Experiments are performed to test the wheel per-formances of climbing slopes using the wheel-terrain interaction testing system developed for lunar rover.A climbing-up-slope model for wheel-terrain interaction is derived according to the conventional wheel-terrain stress distribution models and experimental data.The influence on stress distribution of shallow layer soil caused by slope angle is also considered.An empirical formula for calculating the sinkage exponent as a function of the slip ratio is proposed,in order to reflect the sinkage caused by the soil compaction,scrape,lateral flow,and so on.The model for calculating concentrated force/torque is obtained by integrating the stress distribution formula,which is then verified by experimental data and flexible slope-climbing simulation platform developed secondarily with ADAMS.If the slope is 16º,load is 100 N,and slip ratio increases from 0 to 0.6,the relative errors of predicting normal force,drawbar pull and driving torque between calculation values and experimen-tal data are less than 10%.The model can predict wheel-terrain interaction mechanics effectively for a rover while climbing up slopes.

     

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