Keymasi Khalaji Ali, Jalalnezhad Mostafa
Department of Mechanical Engineering, Faculty of Engineering, Kharazmi University, Tehran, 15719-14911, Iran.
Department of Mechanical Engineering, Faculty of Engineering, Kharazmi University, Tehran, 15719-14911, Iran.
ISA Trans. 2021 Sep;115:32-45. doi: 10.1016/j.isatra.2021.01.016. Epub 2021 Jan 9.
Obtaining a control algorithm capable of navigating the system both in forward and backward motions is one of the control objectives for tractor-trailer wheeled robots (TTWRs). In this paper, a relatively general structure is presented for both forward and backward control of an n-trailer wheeled mobile robot (NTWMR) in the presence of wheel slip effects. To keep better overall performance and track the reference trajectories in forward and backward motions, the NTWMR is intended to be controlled in the presence of slip effects. A control algorithm accompanied by a slip compensation procedure is proposed for the system simultaneously. First, the mathematical model of the system in the presence of slip effects is obtained. A novel physically motivated algorithm is proposed for the tracking control in the presence of unknown uncertainties (longitudinal and lateral slips) for both forward and backward motions. By estimating the slip effects at any instant, the control inputs are produced to compensate for their destructive effects on tracking control of the NTWMR. Then the stability of the closed-loop system is evaluated using the Lyapunov theory. The potential of the proposed controller was verified through several case studies, including comparative results and experimental validation in various motion control manoeuvers for a vehicle with trailers. The proposed method is the first algorithm that can cover a broad range of TTWR motion tasks (forward and backward trajectory tracking, slip attenuation, and global stability), which are required to be developed in NTWMRs.
获得一种能够使系统在向前和向后运动中都能导航的控制算法，是拖挂式轮式机器人（TTWRs）的控制目标之一。本文针对存在车轮打滑效应的n拖挂式轮式移动机器人（NTWMR）的向前和向后控制，提出了一种相对通用的结构。为了在向前和向后运动中保持更好的整体性能并跟踪参考轨迹，NTWMR旨在在存在打滑效应的情况下进行控制。同时为该系统提出了一种伴有打滑补偿程序的控制算法。首先，获得了存在打滑效应时系统的数学模型。针对向前和向后运动中存在未知不确定性（纵向和横向打滑）的跟踪控制，提出了一种新颖的基于物理原理的算法。通过估计任意时刻的打滑效应，产生控制输入以补偿其对NTWMR跟踪控制的破坏作用。然后利用李雅普诺夫理论评估闭环系统的稳定性。通过几个案例研究验证了所提出控制器的潜力，包括在带有拖车的车辆的各种运动控制操作中的比较结果和实验验证。所提出的方法是第一种能够涵盖NTWMR所需的广泛的TTWR运动任务（向前和向后轨迹跟踪、打滑衰减和全局稳定性）的算法。
