针对缺乏精确模型的生物发酵过程中温度的大滞后过程,传统的PID难以达到满意的控制效果.基于专家系统的模糊控制能对一些非线性、模型不是很精确的系统进行控制,在一定程度上能够克服大滞后给系统带来的不利影响,然而模糊控制对延迟时间较大的系统进行控制时容易产生振荡.针对生物发酵过程大滞后系统,本文采用非线性划分的模糊语言变量的模糊免疫自适应Smith控制方案,该方案中自适应Smith预估器能很大程度改善系统的控制品质,增强系统的鲁棒性和抗扰性.非线性划分的模糊语言变量的模糊免疫控制能提高系统的响应时间及其控制精度.两种方法结合,较好利用了非线性划分的模糊语言变量的模糊免疫PID与自适应Smith预估控制的优点.仿真结果表明,基于模糊免疫PID的Smith预估器控制的有效性.%For lack of an accurate model for temperature with large time delay in fermentation processes, the traditional PID control is difficult to acquire satisfying result. As for some nonlinear systems which don't possess accurate models,the fuzzy control based on expert system can overcome the adverse effects caused by large time delay to some extent, but it easily cause oscillation to the long time delay system. Aiming at large delay system in fermentation process, an adaptive smith control method with nonliner division of fuzzy linguistic variable based on fuzzy immune control is proposed in this paper. In this method, the adaptive Smith predictor can improve the control performance and enhance the system robustness and immunity, and the fuzzy immune control can improve system response time and control precision, thus the combination of them can bring their advantages into full play. The simulation results show the effectiveness of this approach.
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