储联罐液位切换控制方法研究
发布时间：2018-12-09 21:00
【摘要】：液位控制作为过程控制的一个重要组成部分,在石油、化工、冶金等工业流程自动化领域占有重要地位。液位控制系统有非线性、不确定性的特点,研究和设计使液位系统具有良好性能的先进控制方案和控制算法一直是学者和机构关注的焦点。本文基于储联罐液位系统的数学模型,设计了液位系统的PID、模糊和线性二次型调节器(linear quadratic regulator—LQR)控制算法,并在此基础上,设计了液位系统的切换控制算法。首先,建立液位系统的数学模型。根据液位系统的文献资料、研究报告,建立基于实验平台的液位系统数学模型。为方便液位系统中控制器的设计,采用泰勒公式将非线性模型展开,给出液位系统的线性模型。然后,围绕建立的系统的线性模型,提出了PID控制算法,模糊控制算法和LQR控制算法。根据各控制算法的原理,分别设计PID控制器的比例、积分、微分控制参数,模糊控制器的模糊控制规则、隶属度函数和解模糊方法以及LQR控制器的状态加权矩阵和控制加权矩阵,给出液位系统的各控制算法的控制器结构,仿真结果表明所述的三种控制方法均能使液位系统取得令人较为满意的控制效果,但LQR控制算法对液位系统具有最佳的稳定性。最后,在对比分析所提出的三种控制算法的基础上,针对液位系统在液位初始上升阶段模型不确定问题并使系统具有良好的稳定性,提出了液位系统的模糊和LQR切换控制方案。利用“分解—合成”的多模型建模策略,将液位系统的工作范围划分为多个工作小区间,建立系统的多模型集合,基于系统的模型集合设计系统的控制器集合,并根据系统液位反馈值设计模糊、LQR控制切换准则。为保证系统在液位稳定的情况下实现控制器之间的平稳切换,避免出现液位大幅度波动现象,设计了模糊和LQR的加权控制。仿真结果说明提出的控制方案对液位系统具有良好稳定性。
[Abstract]:As an important part of process control, liquid level control plays an important role in petroleum, chemical, metallurgical and other industrial process automation fields. Liquid level control system has the characteristics of nonlinearity and uncertainty. The research and design of advanced control schemes and control algorithms that make the liquid level control system have good performance has been the focus of attention of scholars and institutions. Based on the mathematical model of the liquid level system of the storage tank, this paper designs the PID, fuzzy and linear quadratic regulator (linear quadratic regulator-LQR control algorithm of the liquid level system, and on this basis, designs the switching control algorithm of the liquid level system. Firstly, the mathematical model of liquid level system is established. According to the literature and report of the liquid level system, the mathematical model of the liquid level system based on the experimental platform is established. In order to facilitate the design of controller in liquid level system, the nonlinear model is expanded by Taylor formula, and the linear model of liquid level system is given. Then, the PID control algorithm, fuzzy control algorithm and LQR control algorithm are proposed around the linear model of the system. According to the principle of each control algorithm, the proportion, integral and differential control parameters of PID controller and the fuzzy control rules of fuzzy controller are designed respectively. The membership function and fuzzy method, the state weighting matrix and control weighting matrix of LQR controller are given, and the controller structure of each control algorithm of liquid level system is given. The simulation results show that the three control methods mentioned above can make the liquid level system achieve a satisfactory control effect, but the LQR control algorithm has the best stability to the liquid level system. Finally, on the basis of comparing and analyzing the three control algorithms proposed, a fuzzy and LQR switching control scheme for the liquid level system is proposed in view of the uncertainty of the model of the liquid level system in the initial rising stage of the liquid level and the good stability of the system. By using the multi-model modeling strategy of "decomposition-synthesis", the working range of the liquid level system is divided into several working intervals, and the multi-model set of the system is established, and the controller set of the system is designed based on the model set of the system. Fuzzy and LQR control switching criterion are designed according to the feedback value of system liquid level. In order to ensure the smooth switching between controllers and avoid the phenomenon of large fluctuation of liquid level, fuzzy and LQR weighted control are designed. The simulation results show that the proposed control scheme has good stability to the liquid level system.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP273
本文编号：2370026
[Abstract]:As an important part of process control, liquid level control plays an important role in petroleum, chemical, metallurgical and other industrial process automation fields. Liquid level control system has the characteristics of nonlinearity and uncertainty. The research and design of advanced control schemes and control algorithms that make the liquid level control system have good performance has been the focus of attention of scholars and institutions. Based on the mathematical model of the liquid level system of the storage tank, this paper designs the PID, fuzzy and linear quadratic regulator (linear quadratic regulator-LQR control algorithm of the liquid level system, and on this basis, designs the switching control algorithm of the liquid level system. Firstly, the mathematical model of liquid level system is established. According to the literature and report of the liquid level system, the mathematical model of the liquid level system based on the experimental platform is established. In order to facilitate the design of controller in liquid level system, the nonlinear model is expanded by Taylor formula, and the linear model of liquid level system is given. Then, the PID control algorithm, fuzzy control algorithm and LQR control algorithm are proposed around the linear model of the system. According to the principle of each control algorithm, the proportion, integral and differential control parameters of PID controller and the fuzzy control rules of fuzzy controller are designed respectively. The membership function and fuzzy method, the state weighting matrix and control weighting matrix of LQR controller are given, and the controller structure of each control algorithm of liquid level system is given. The simulation results show that the three control methods mentioned above can make the liquid level system achieve a satisfactory control effect, but the LQR control algorithm has the best stability to the liquid level system. Finally, on the basis of comparing and analyzing the three control algorithms proposed, a fuzzy and LQR switching control scheme for the liquid level system is proposed in view of the uncertainty of the model of the liquid level system in the initial rising stage of the liquid level and the good stability of the system. By using the multi-model modeling strategy of "decomposition-synthesis", the working range of the liquid level system is divided into several working intervals, and the multi-model set of the system is established, and the controller set of the system is designed based on the model set of the system. Fuzzy and LQR control switching criterion are designed according to the feedback value of system liquid level. In order to ensure the smooth switching between controllers and avoid the phenomenon of large fluctuation of liquid level, fuzzy and LQR weighted control are designed. The simulation results show that the proposed control scheme has good stability to the liquid level system.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP273
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