Exploring Tractive Performance of Planetary Rover's Rigid Wheels on Mixed Terrain

星球车刚性车轮在混合地形上牵引性能研究

School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China

Received: 3 March 2020

Abstract

Based on insufficient studies of the tractive performance of a planetary rover's rigid wheels in soft soil and hard mixed soil terrains, a method for studying the tractive performance is presented. The Wong-Reece' interaction model was used as the dynamic model for wheel-soil contact. The sinkage model and the drawbar pull force model were modified and then verified with experimental results. Based on the Hertz contact theory, a nonlinear friction spring damping model was adopted as the wheel-bedrock contact model. An additional terrain hardness array was introduced for setting and recognizing the mixed terrain with ground mechanics parameters. With the platform for co-simulating the navigation and dynamics of a planetary rover, the simulation program was developed to dynamically simulate the whole planetary rover with two wheel-ground contact models. Taking the Mars rover as an example, its whole model was established with the MSC.Adams software. The dynamic simulation of the Mars rover on the soft terrain and mixed terrain was carried out respectively. The simulation results show that the Mars rover's velocity fluctuates greatly on the mixed terrain, and that the Mars rover gains greater drawbar pull force when traveling on the mixed terrain than on the only soil terrain.

摘要

针对星球车刚性车轮在混合地形中牵引性能研究的不足，提出了一种对刚性车轮在混合地形中牵引性能的研究方法。对Wong-Reece模型的沉陷量和挂钩牵引力进行修正，建立刚轮-软土接触模型并实验验证；刚轮-硬石接触模型采用基于Hertz接触理论的含摩擦非线性弹簧阻尼模型。地面力学参数中新添加地形刚度以实现混合地形的设置和识别。基于星球车导航与动力学联合仿真平台扩展开发，编制相应仿真程序，形成含有2种轮地接触模型的整车动力学仿真能力。以火星车为例，通过MSC.Adams软件和自编程序建立火星车整车模型，分别在软土地形和混合地形中对其进行动力学仿真，给出牵引动力学特性。结果表明，在混合地形上火星车的车体速度波动较大，某些混合地形条件下火星车可获得更大的挂钩牵引力。