为实现月面巡视器GNC系统的闭环测试,研究了六轮摇臂式巡视器在月表崎岖地形、松软土壤和低重力环境下的动力学建模与控制问题。基于弹塑性轮-土力学和粘弹性运动副约束分析,建立了巡视器的牛顿-欧拉动力学模型。以跟踪期望速度、角速度为目标,采用速度协调控制和车轮滑移控制,完成了巡视器闭环牵引控制。在实时操作系统下实现了巡视器动力学模型和牵引控制系统,并建立了三维可视化平台,对该动力学模型和牵引控制方法进行验证。测试结果证实了建立的动力学模型准确、稳定,可以真实地模拟巡视器在月球表面的运动行为和轮-土作用关系,且满足运动副的约束;所设计的牵引控制方法可以较准确地实现巡视器跟踪期望的运动。
To finish the closed-loop test of the lunar rover GNC test system, the dynamics modeling and control problem of a six-wheel rocker-bogie lunar rover is studied under the condition of rough terrain, soft soil and low-gravity. A Newton-Euler dynamics model of the rover is established based on elastoplastic wheel-terrain mechanics and viscoelastic joints. Velocity cooperative control considering the slip of wheels is used for the closed-loop traction control, with the goal to track desired velocity and angular velocity of the rover. Both dynamics model and traction control system are finished on a real-time syetem to evaluate the model and the control method, and a 3D visualization simulation platform is developed. Experimental results show that the model is accurate and steady, the rover motion and wheel-terrain interaction can be truly simulated, the joint constraints are satisfied, and the desired motion can be accurately tracked.