鼓形驱动轮与松散沙土相互作用力学分析

为给月球车结构设计、运动控制和模拟仿真等提供必要的轮-地相互作用理论模型,基于车轮与松散沙土间的承压、剪切特性理论,建立了鼓形驱动轮与松散沙土相互作用力学模型.通过分析轮-地接触法向应力与切向应力分布,考虑最大法向应力向车轮前方偏移的现象,引入最大法向应力角随滑转率变化的理论公式,分析鼓形轮运动特性指标与松散沙土力学参数及车轮参数间的定量关系.依据松散沙土力学参数测量,指出剪切变形模量与接地比压的定量表达式,通过分析鼓形轮的接地面积,确定对应于载荷的剪切变形模量值.利用月球车车轮运动性能综合测试系统进行了鼓形轮在松散沙土上的滚动力学实验,结果验证了利用该理论模型预测鼓形轮运动性能的可行性.

Mechanical analysis of a drum type wheel rolling on loose sandy soil

Based on pressure sinkage laws and shear stress-displacement relationships in terramechanics, a mathematical model was developed to describe the motion performance of a drum type wheel. This should improve design, motion control, and vehicle simulation for the lunar rover. After establishing quantitative relationships between motion performance, soil properties and wheel dimensions, the drum wheel was divided into many slim cylindrical wheels. When analyzing radial and tangential stress distributions under the wheel-soil interface, it was found that maximum radial stress occurs in front of bottom-dead-centre and shifts forward when increasing slip is taken into account. On the basis of parameter measurements of loose sandy soil, the relationship between shear modulus and contact pressure was introduced. For theoretical analysis, the value of shear modulus which corresponds to load exerted on the experiment wheel was obtained by defining the area of drum wheel-soil contact. Experimental results from a single-wheel testbed operated in loose sandy soil shows that this model for predicting drum wheel performance is reliable.