改进型模糊内模控制在不稳定时滞系统中的应用

Application of Improved Fuzzy IMC in Unstable Systems

开环不稳定时滞系统是工业现场中常见的一类被控过程,这类系统控制难度高,控制精度难以保证。因此提出一种包含三个控制器的改进型内模控制结构,实现设定值跟踪和抗扰性的独立设计,并且根据对系统跟踪性能与鲁棒性能的分析给出了控制器参数的整定方法。对于时变系统,把模糊控制方法引入到改进型内模控制结构中,建立了滤波器时间常数的模糊自整定规则,通过在线实时调整滤波器时间常数来增强系统的鲁棒性。仿真结果表明该结构具有较好的跟踪性能和鲁棒性,参数调节容易,易于工程实施。

Open-loop unstable system with time delay is difficult to control using routine control methods. To solve this problem, an improved internal model control scheme was proposed, which consists of three controllers. Set point tracking and disturbance restraint performance can be designed independently. The tuning formulas of the controllers were confirmed by analysis of tracking performance and robustness. Fuzzy self-tuning rules of the filter time constant were built for the time-varying system, so the filter time constant can be modified real-timely in order to improve the closedloop response performance. Simulations show that the improved IMC method is not only effective for the dynamics and the stability of control system but also for the process robustness. In addition, the proposed method is easy to regulate, and it is fit for engineering application.