基于改进Smith预估器的二阶时滞系统

A 2^(th) Order Time Delay System Based on Improved Fuzzy Smith Predictor

在关于工业过程控制的研究中,针对常规Smith预估器是基于时滞对象精确数学模型,而在实际应用中,当被控系统的参数不稳定或受到扰动时,就会造成Smith预估模型的失控,使得控制效果变差甚至振荡。尽管模糊Smith预估控制对系统参数的变化不敏感,但并没有从本质上克服预估模型失控给系统带来的不稳定性影响。为解决时滞引起失控的问题,提出了一种改进的模糊Smith预估控制方法,并对方法进行了仿真。仿真结果表明,能够增强系统的稳定性、鲁棒性,并且具有较好的控制精度,为实际工程设计提供了参考。

As traditional Smith predictor is based on precise time delay system model, when system parameters are unstable or disturbed, the Smith predictor model and system model will not match, this will lead to bad control effect or even make system oscillatory. Although fuzzy control is not sensitive to the variety of system parameters, it dose not overcomes the bad influence in essence. This paper analyzed the three factors leading to model mismatch, and introduced an improved Fuzzy Smith controller. The results of simulation show that this method makes system re- markably stable and robust, has well control precision, and provides reference for practical engineering application.