自主行驶调平系统建模及自适应反步滑模控制  

Modeling and adaptive backstepping sliding mode control of autonomous driving leveling system

作　　者：向洋 蒙艳玫[1] 韦锦[1] XIANG Yang;MENG Yanmei;WEI Jin(School of Mechanical Engineering,Guangxi University,Nanning 530004,China)

机构地区：[1]广西大学机械工程学院,广西南宁530004

出　　处：《广西大学学报（自然科学版）》2024年第1期78-87,共10页Journal of Guangxi University（Natural Science Edition）

基　　金：国家自然科学基金项目(52365001);广西创新驱动发展专项基金项目(桂科AA19254019)。

摘　　要：为了解决车载式绿篱修剪机在自主行驶作业时车身无法根据地形起伏自适应平衡,提高作业安全性和绿篱修剪的尺寸精度,设计了一种自主行驶车身电液调平系统,该系统采用倾角传感器实时监测车身倾斜角度,根据车身调平机构动力学理论建立了调平系统的数学模型。针对电液调平系统参数的不确定性、非线性特性和外界环境的干扰等问题,通过结合滑模控制和自适应反步法设计了自适应反步滑模控制器,根据反步法的思想,将系统分解为多个子系统,并为每个子系统选择适当的Lyapunov函数。通过逐层递推的方法,最终可以得到控制系统的控制律和不确定参数的自适应律,并且证明了系统跟踪误差的收敛性。针对滑模控制带来的抖振问题,使用饱和函数代替传统符号函数,使得系统抖振得以削弱。仿真研究结果表明,在车身倾斜20°的情况下,实际输出角度能准确、快速地跟踪参考角度,响应时间短,对参数变化具有较强自适应性和鲁棒性,能实现车身快速、准确调平。与比例积分微分控制器相比,调平时间缩短了1/5,系统调平误差小于1°,调平过程更加稳定。To solve the problem that the vehicle-mounted hedge trimmer cannot adaptively balance itself according to the topographic relief during autonomous driving operations,and improve the operational safety and the dimensional accuracy of hedge trimming,an autonomous driving vehicle body electro-hydraulic leveling system was designed.The system used a tilt sensor to monitor the vehicle body tilt angle in real time,and established a mathematical model of the leveling system based on the dynamics theory of the vehicle body leveling mechanism.In view of the uncertainty,nonlinear characteristics,and external environmental interference of the electro-hydraulic leveling system parameters,an adaptive backstepping sliding mode controller was designed by combining sliding mode control and adaptive backstepping method.According to the idea of backstepping method,the system was decomposed into multiple subsystems,and appropriate Lyapunov functions were selected for each subsystem.Through the recursive method,the control law of the control system and the adaptive law of the uncertain parameters was obtained,and the convergence of the system tracking error was proved.In view of the chattering problem caused by sliding mode control,a saturation function was used instead of the traditional sign function,which weakened the chattering of the system.The simulation results show that under the condition of a vehicle body tilt of 20°,the actual output angle can accurately and rapidly track the reference angle,with a short response time,strong adaptability and robustness to parameter changes,and can achieve rapid and accurate vehicle body leveling.Compared with the PID controller,the leveling time is reduced by 5 times,and the system leveling error is less than 1°,making the leveling process more stable.

关 键 词：电液调平系统 自适应反步控制 滑模控制 

分 类 号：TP273[自动化与计算机技术—检测技术与自动化装置]