分布式驱动—转向多级铰接移动机器人构形设计及控制方法

Configuration Design and Control Methods of Distributed Driving-Steering Multi-body Articulated Mobile Robot

  • 摘要: 铰接移动机器人平台具有运载量大、模块组合灵活等优点,但存在通过性差、内稳定性差等突出问题,极大限制了运载场景和效率。本文设计了一种搭载分布式驱动与转向机构的多级铰接移动机器人平台及其控制方法。首先,基于多级铰接平台的递推运动学和动力学特征分析并提出了前轴驱动、后轮转向的全挂型挂车分布式转向和驱动部署方案。而后,针对多级铰接平台转弯扫掠面积大导致的通过性差问题,设计了基于运动学推演和坐标系变换的挂车后轮转向模块化反馈控制算法,实现铰接平台的同一路径行驶;针对多级铰接平台内稳定性差的问题,设计了基于前馈与反馈融合的分布式驱动控制方法,实现了铰接平台在高速转向、制动等易失稳工况下的协同稳定行驶。最后,以4节铰接移动机器人平台为例进行仿真与实物实验。实验表明分布式后轮转向法使挂车相对于牵引车的最大轨迹偏差下降约93%;协同驱动控制法使平台在0.1 rad转向角下最大稳定行驶速度从8 m/s提升至14 m/s,直线制动减速度从-1 m/s2提升至-4 m/s2

     

    Abstract: The articulated mobile robot platform has the advantages of large carrying capacity and flexible module combinations, but it faces prominent issues such as poor trafficability and internal stability, which limit the transport scenarios and efficiency. A multi-body articulated mobile robot platform equipped with distributed driving and steering devices and its control methods are designed. Firstly, a distributed steering and driving deployment scheme for full-trailer with front axle driving and rear axle steering is proposed based on the recursive kinematic and dynamic characteristics of the multi-body articulated platform. Secondly, a modular feedback control algorithm based on kinematic deduction and coordinate transformation for trailer rear-wheel steering is designed to address the poor trafficability resulting from the large turning swept area of the multi-body articulated platform, which achieves the same path following of articulated platform. For the poor internal stability in the multi-body articulated platform, a distributed drive control method based on the fusion of feedforward and feedback is designed, which achieves the coordinated stable operation of the articulated platform in high-speed steering,braking, and other potentially unstable conditions. Finally, simulations and physical experiments on a four-body articulated mobile robot platform are carried out. The experiments show that the distributed rear-wheel steering reduces the maximum trajectory deviation of the trailer from the towing vehicle by approximately 93%. Coordinated drive control increases the maximum stable driving speed of the platform from 8 m/s to 14 m/s at a steering angle of 0.1 rad, and improves the linear braking deceleration from -1 m/s2 to -4 m/s2.

     

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