改进模糊PID控制在八磁极径向电磁轴承中的应用

Application of Radial Active Magnetic Bearing Based on Improved Fuzzy PID Controller

以具有解耦作用的八磁极径向AMB为研究对象,基于对象的离散模型设计了常规数字PID控制器使系统稳定。考虑到实际AMB系统具有一定的不确定性,且常规PID对于非线性、结构参数不确定、被控对象受外部影响较大的系统,其控制性能往往不够理想,设计了具有参数在线调整功能的模糊PID控制器。由于模糊PID的变量基本论域在实际的控制过程保持不变,一定程度上降低了控制的精度,为此进一步设计了基于比例缩放思想的改进模糊PID控制器。仿真结果表明:改进模糊PID控制相较于其他控制方法具有更好的控制性能。

This paper establishes a discrete mathematical model of the radial magnetic bearing with eight magnetic poles which can decouple the effect of cross coupling. First of all,a conventional digital PID controller is designed based on the discrete model to make the system stable. Considering the actual AMB is a kind of uncertain system,and the poor control performance of the conventional PID controller used in the system which is nonlinear or include uncertain structural parameters and controlled objects influenced by external factors greatly. In this paper,the fuzzy PID controller is designed which achieves the online adjusting function for PID parameters. In view of basic variable sets of the fuzzy PID stay the same which conduct the lower control precision in the practical control process of AMB,this paper designs an improved fuzzy PID controller based on the thought of variable universe of proportion scaling. The simulation results show that the improved fuzzy PID control has better control performance compared with the other control methods.