基于改进ESO的磁悬浮系统模型参考滑模控制

为了提高磁悬浮输送带的稳定性，减小未建模动态和未知外界干扰对磁悬浮系统控制性能的影响，基于改进的扩张状态观测器（extend state observer， ESO）技术，提出了一种模型参考滑模控制与基于改进趋近律的滑模控制相结合的控制策略。首先，对参考模型进行滑模设计，在此基础上根据磁悬浮系统的快速响应和鲁棒性要求，结合幂次趋近律和指数趋近律对传统趋近律进行改进，设计了一种基于新型趋近律的滑模控制；其次，设计了一种新的非线性函数对ESO进行改进，基于改进的ESO对系统的扰动和状态进行观测和估计，将观测结果加入新型滑模控制器以对外界干扰进行补偿，来提高新型滑模控制器的控制性能。仿真结果表明：所设计的控制策略与传统基于指数趋近律的滑模控制相比，磁悬浮系统气隙输出的超调量减小了15.15%，系统具有更高的鲁棒性；与基于改进趋近律的滑模控制方法相比，所提出的控制器可以使系统无抖振，有更好的跟踪性能。在基于改进ESO的模型参考滑模控制下，磁悬浮系统能够稳定运行，具有较好的控制性能。研究结果对磁悬浮输送机输送带的悬浮控制具有一定的参考价值。

Model reference sliding mode control of magnetic levitation system based on improved ESO

In order to improve the stability of magnetic levitation conveyor belt and reduce the influence of unmodeled dynamics and unknown external interference on the control performance of magnetic levitation system,a control strategy combining model reference sliding mode control and sliding mode control based on improved reaching law was proposed based on the improved ESO(extended state observer)technology.Firstly,the sliding mode design of the reference model was carried out.On this basis,according to the requirements of fast response and robustness of the magnetic levitation system,the traditional reaching law was improved by combining the power reaching law and exponential reaching law,and then a sliding mode control based on the new reaching law was designed;secondly,a new nonlinear function was designed to improve ESO.Based on the improved ESO,the disturbance and state of the system were observed and estimated,and the observation results were added to the new sliding mode controller to compensate the external interference,so as to improve the control performance of the new sliding mode controller.The simulation results showed that compared with the traditional sliding mode control based on exponential reaching law,the overshoot of air gap output of magnetic levitation system was reduced by 15.15%,and the system had higher robustness;compared with the sliding mode control method based on the improved reaching law,the proposed controller could make the system free of chattering and have better tracking performance.Under the model reference sliding mode control based on the improved ESO,the magnetic levitation system can operate stably and has good control performance.The research results have certain reference value for the levitation control of magnetic levitation conveyor belt.