Authors

Abstract

A sliding mode active disturbance rejection tracking control scheme based on the Smith predictive control structure is pro-posed for the front steering wheel of tractors, aiming to address the challenges of time delay and unknown disturbances in the angle tracking process. In the control system design, the effects of time delay and disturbances on the angle tracking performance are thoroughly considered, based on the established steering system model. A time delay processing struc-ture is designed based on the Smith predictive control principle, and linear extended state observer is designed to realize synchronous estimation for the un-delayed angle output and the controller output. A simple Sliding Mode Controller (SMC) is introduced to replace the linear feedback controller in active disturbance rejection control (ADRC) to improve the accu-racy and disturbance rejection performance. Simulation charts and performance evaluating indexes show that the pro-posed control method has obvious advantages in tracking accuracy, robustness and disturbance rejection in comparison with other methods. The angle tracking error is no more than 0.055rad even under the interference of white noise signal. The proposed method effectively mitigates the impact of time delay and disturbance, it can significantly enhance the dy-namic response performance of the steering system.

Abstract in Chinese

针对拖拉机前轮转角控制系统存在滞后、易受未知干扰等不确定因素影响问题，提出一种基于史密斯预估控制结构的滑模自抗扰转角跟踪控制方案。根据确定的转向系统模型，考虑延迟环节、内外部干扰对转角跟踪效果的影响，基于史密斯控制预估思想，设计时滞处理结构，通过线性扩展状态观测器实现对无滞后角度输出和控制器输出的同步估计。设计简单的滑模控制器替代自抗扰控制中的线性反馈控制，进一步提高转向角跟踪控制的精度和扰动抑制能力。仿真曲线及性能评价指数显示，与其它控制方法相比，本文提出的控制方法在跟踪精度、鲁棒性和抗扰动性等各方面都具有明显的优越性，即使在白噪声信号干扰下，对设定角度的跟踪误差也不超过0.055rad。结果表明，提出的方法能够有效应对系统中存在的时滞及扰动对转角跟踪效果造成的影响，可进一步提高转向系统的动态响应性能。