多变量分子蒸馏蒸发过程解耦控制方法研究

发布时间：2018-06-07 02:54

本文选题：分子蒸馏 + 系统辨识　；参考：《长春工业大学》2015年硕士论文

【摘要】：分子蒸馏蒸发过程具有多变量、强耦合、大时滞的特点,其自动控制系统的多个控制回路同时工作时,所有回路间具有强烈的耦合特性,互相作用。这种耦合作用直接影响到分子蒸馏蒸发过程的控制品质和稳定性。本文通过建立被控对象的数学模型和设计解耦控制系统的方法以减小多个控制回路之间的相互作用,提高分子蒸馏蒸发过程的控制性能和稳定性。为有效分析分子蒸馏系统中的蒸发环节,本文提出了一种带有延迟环节的多变量系统参数辨识方法。采取将多变量系统辨识问题转化为多个单变量系统辨识问题的思想,对辨识问题进行简化,并给出了该思想的依据。依据阶跃激励信号下被辨识过程的响应数据建立关系式组,并应用辛普森(Simpson)积分公式得到了关系式组中未知系数,通过对该关系式组的求解最终获得蒸发系统的传递函数矩阵。仿真及实际过程中的应用表明,采用的辨识方法具有较强的可实践性,及良好的辨识效果。本文采用对角阵解耦法对两输入、两输出分子蒸馏蒸发过程进行解耦,并得出了分子蒸馏蒸发过程解耦补偿器的传递函数矩阵,通过该解耦补偿器可使得本文研究的分子蒸馏蒸发过程的传递函数矩阵转变为一对角矩阵,从而解除两个控制回路之间的耦合,使分子蒸馏蒸发过程实现完全解耦。针对解耦后等效过程设计内模控制器,将解耦器中的时滞项做了近似处理,再对近似后的解耦环节利用Maclaurin公式展开,得到了PID控制器的三个参数,形成一套完整的多变量系统的解耦控制方案。利用该方法对本文第三章解耦后分子蒸馏系统进行了验证,试验结果表明通过该方法得到的控制器具有良好的抗干扰性能和良好的鲁棒性。且本文提供的控制器的设计步骤简洁明了,方便于工程应用软件实现。用C++语言在ADS1.2平台上编写了可在基于X86架构CPU的PC上运行的解耦控制软件,该软件实现了对一个两输入两输出过程的解耦环节及控制器参数的全自动计算的功能。
[Abstract]:The evaporation process of molecular distillation has the characteristics of multivariable, strong coupling and large time delay. When the multiple control loops of the automatic control system work simultaneously, all the circuits have strong coupling characteristics and interact with each other. This coupling directly affects the control quality and stability of the molecular distillation evaporation process. In this paper, the mathematical model of the controlled object and the design of decoupling control system are established to reduce the interaction between multiple control loops and to improve the control performance and stability of the molecular distillation evaporation process. In order to effectively analyze the evaporation process in molecular distillation system, a multivariable system parameter identification method with delay link is presented in this paper. The idea of converting multivariable system identification problem into multiple single variable system identification problem is adopted to simplify the identification problem and the basis of this idea is given. Based on the response data of the identified process under the step excitation signal, the relational group is established, and the unknown coefficients in the relational group are obtained by applying Simpson Simpson's integral formula. Finally, the transfer function matrix of the evaporation system is obtained by solving the relation group. The simulation and practical application show that the proposed identification method has strong practicability and good identification effect. In this paper, two input and two output molecular distillation processes are decoupled by diagonal array decoupling method, and the transfer function matrix of decoupling compensator for molecular distillation evaporation process is obtained. By using the decoupling compensator, the transfer function matrix of the molecular distillation evaporation process studied in this paper can be transformed into a pair of angular matrices, so that the coupling between the two control loops can be uncoupled and the molecular distillation evaporation process can be completely decoupled. For the decoupled equivalent process, the internal model controller is designed. The delay-term in the decoupling is treated approximately, and then the decoupling link is expanded by Maclaurin formula, and the three parameters of the PID controller are obtained. A complete decoupling control scheme for multivariable systems is formed. The method is used to verify the decoupled molecular distillation system in chapter 3 of this paper. The experimental results show that the controller obtained by this method has good anti-interference performance and good robustness. The design steps of the controller provided in this paper are simple and clear, which is convenient for engineering application software. The decoupling control software which can be run on PC based on X86 CPU is written on ADS1.2 platform with C language. The software realizes the function of decoupling link of a two-input and two-output process and the automatic calculation of controller parameters.
【学位授予单位】：长春工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ028.61;TP273

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