基于LESO的改进滑模磁悬浮控制算法

Improved sliding mode magnetic levitation control algorithm based on LESO

针对磁悬浮系统具有的非线性、时滞性、强扰动等特性,提出一种基于线性扩张状态观测器的改进滑模控制方法。首先,建立电磁悬浮系统的数学模型,通过分析模型的动力学特性,将数学模型线性化;其次,为了改善一般滑模变结构控制的抖振问题,采用改进的滑模控制方法,通过引入边界可变幂fal函数代替Sign符号函数且关联滑模增益和超平面函数,抑制系统抖振引起的不稳定性;最后,引进LESO观测器主要将系统总扰动量反馈补偿给滑模控制器,既可以缓解滑模控制器对模型的依赖程度,又能进一步提高系统抗干扰性和鲁棒性。仿真结果表明:相比于传统算法,基于LESO的改进滑模控制减小超调、较快响应速度、大幅度增强系统抗干扰性能和鲁棒性,对于克服中低速电磁悬浮列车在不同工况和复杂环境下运行的工程实现难题具有理论指导意义。

As the magnetic levitation system has nonlinearity,time delay,strong disturbance characteristics,an improved sliding mode control method based on linear expansion state observer is proposed in this paper.Firstly,the mathematical model of the electromagnetic levitation system was established,and the mathematical model was linearized by analyzing the dynamic characteristics of the model.Secondly,an improved sliding mode control method is used to improve the jitter problem of general sliding mode variable structure control.By introducing the boundary variable power function fal instead of the symbolic function Sign and associating the sliding mode gain and hyperplane functions,the instabilities caused by system jitterare suppressed.At last,the LESO observer is introduced to compensate the total disturbance of the system to the sliding mode controller,which could reduce the dependence of the sliding mode controller on the model and further improve the anti-interference and robustness of the system.Simulation results show that,compared to traditional algorithms,improved sliding mode control based on LESO provides faster response times,reduces overshoot,greatly enhances the anti-interference and robustness performance of the system.It has theoretical guiding significance for overcoming the engineering realization puzzle of medium and low speed electromagnetic levitation trains running under different working conditions and complex environments.