【作者】 王璐；

【导师】 陈娟；

【作者基本信息】 北京化工大学 ， 控制理论与控制工程， 2008， 硕士

【摘要】 时滞系统的控制是工业上经常遇到的问题。针对工业控制过程中的时滞系统,本文基于内模控制原理,设计了滤波器时间常数自调整内模控制。在建立滤波器时间常数λ模糊自整定方法的基础上,研究了采用伸缩因子变论域的滤波器时间常数λ自调整模糊内模控制,提出了滤波器时间常数的变论域模糊控制改进方法,并推导出了指数型伸缩因子、研究了幂函数型伸缩因子的性质。主要从以下几个方面开展了研究工作:1.基于内模控制原理设计方法,将内模控制方法引入到Smith预估控制中,建立了滤波器时间常数λ的在线自整定方法。利用模糊控制理论确立了滤波器时间常数λ的模糊整定规则,通过在线调整滤波器时间常数改善了内模控制系统闭环特性。2.研究了模糊控制过程中输入输出论域的伸缩变化对控制性能的影响以及如何利用论域的变化提高控制性能。提出了基于量化因子的变论域模糊控制方法。分析并总结控制参数(量化因子(quantitative factors))在控制中的变论域作用,指出参数与变论域伸缩因子的关系。3.根据变论域理论,以及伸缩因子的数学特性及工程特性,推导出了幂函数型伸缩因子,论证了幂函数型伸缩因子的数学特性及工程特性。4.针对工业过程中常见的一阶时滞过程、二阶时滞过程,并分别在模型匹配、模型失配以及模型不确定和干扰的情况下,分别采用传统模糊控制、改进变论域模糊控制及采用幂函数型伸缩因子的变论域模糊控制进行了Matlab仿真实验研究。结果证明,与传统的模糊控制方法相比,文中提出的改进变论域模糊控制方法不仅能够获得更高的控制精度,也提高了系统的响应速度;同时,幂函数型伸缩因子亦利于硬件实现,对慢响应的化工系统和快速响应的机电系统的在线控制提供了有效途径。更多还原

【Abstract】 The control for processes with time-delay is always encountered in industry. Aim at this problem, this paper presents a filter time constant A self-adjusting internal model control (IMC) based on variable domain fuzzy control. A modified variable domain fuzzy control method is proposed on the basis of quantitative factor and the nature of power function contraction-expansion factor has been researched.Mainly from the following aspects the research work was carried out:1. Based on the principle of internal model control (IMC), the IMC design method was be introduced to Smith predictive control. Firstly, the filter time constant on-line self-tuning method was proposed; then, the filter time constant fuzzy rules was established according to fuzzy control theory. The closed-loop characteristics can be improved by adjusting the filter time online.2. The domain contracting (expanding) of input and output will affect the control performance. Therefore, the paper has researched on this aspect, and how to improve the performance by using it has also been studied. According to the research, the paper proposed a modified variable domain fuzzy control based on quantitative factors. Then the analysis about the relationship between control parameter (quantifiable factor) and the contraction-expansion factor was presented.3. The paper has studied the mathematical and engineering characteristics of the general contraction-expansion factor. Based on the study and variable domain fuzzy control theory, the power function contraction-expansion factor is derived. 4. For illustration, aiming at first-order and second-order time-delay processes, the simulation experiments are taken respectively, when model is accurate and inaccurate or uncertain process and disturbance exits by using different contraction-expansion factors.The simulations show that, the method proposed has better performance than the traditional fuzzy control. Not only the problems of high accuracy request for model in Smith controller、model mismatch and uncertain model have been solved, but also can obtain the better compromise control effect between and system response and robustness. Furthermore, according to the modified method, only one fuzzy control rules look-up table needs to be established in application; and the power function contraction-expansion factors are available for hardware implementation both of which are available for slow-response chemical system and rapid-response mechanical system.更多还原