汽车防抱死制动系统的自抗扰控制研究

汽车防抱死制动系统（Anti-lock Braking System，ABS）的作用是确保汽车制动时行驶方向的稳定性、可靠性，但是目前仍存在非线性、时变性以及参数不确定性等问题。为保证汽车制动行驶过程中的操纵稳定性和安全性，进一步实现各工况下防抱死制动系统的优化控制，以影响整车稳定的变量滑移率为研究对象，分析所设计策略的控制效果。搭建汽车动力学模型、制动系统模型、轮胎模型和滑移率模型等主要模型，设计基于滑移率的ABS二阶非线性自抗扰控制器。运用MATLAB/Simulink软件对基于自抗扰控制（Active Disturbance Rejection Control，ADRC）的ABS制动过程和基于模糊PID控制的ABS制动过程进行仿真，对比研究最佳滑移率、载荷、水泥-冰对接路面、扰动等对制动过程中的轮速、车速以及滑移率等动态性征反映的稳定性和抗扰能力的影响，同时研究其对最终制动距离和最终制动时间反映的制动性能的影响。最后，将自抗扰控制器和模糊PID控制器装配于试验车辆的ABS，进行水泥路面和冰-水泥对接路面制动过程的实车试验。研究结果表明：基于二阶非线性自抗扰控制算法的ABS制动的最终制动距离和最终制动时间更短、制动效果更优，制动过程中的轮速、车速和滑移率在响应速度、稳定性和抗扰能力等方面均更佳；试验结果与仿真结果吻合，证明了仿真模型及其仿真结果的可行性和正确性。

Active Disturbance Rejection Control for Automotive Anti-lock Braking System

Anti-lock braking systems (ABSs) are utilized in automobiles to ensure the directional stability of the vehicle during braking. However, these systems can be negatively affected by nonlinearity, time variability, and parameter uncertainty. Therefore, to ensure vehicle stability and safety during braking, and to realize the optimal control for an anti-lock braking system under various working conditions, the control effect of a design strategy based on the variable slip rate that affects vehicle stability is analyzed in this paper. For this purpose, an automobile dynamics model, a braking system model, a tire model, and a slip rate model were constructed, and an ABS second-order nonlinear active disturbance rejection controller based on the slip rate was designed. MATLAB/SIMULINK software was used to simulate the ABS braking process based on active disturbance rejection control (ADRC) and fuzzy proportional-integral-derivative (PID) control. The effects of the optimal slip rate, load, cement-ice docking road, and disturbance on the stability of dynamic characteristics such as wheel speed, vehicle speed, and slip rate during the braking process were compared, and their effects on the final braking distance and final braking time were also studied. The simulation results show that the final braking distance and final braking time of ABS braking based on the second-order nonlinear ADRC algorithm are shorter, and that the braking effect is superior. Further, the wheel speed, vehicle speed, and slip ratio during the braking process possess superior response speeds, stabilities, and immunities. Finally, an active disturbance rejection controller and fuzzy PID controller were assembled in the ABS of an experimental vehicle, and l vehicle experiments were conducted to investigate the braking process on cement pavement and icy cement pavement. The experimental results are consistent with the simulation results, which demonstrates the feasibility and accuracy of the simulation model.