【作者】 刘媛媛；

【导师】 张卫东；

【作者基本信息】 上海交通大学 ， 控制理论与控制工程， 2008， 博士

【摘要】 先进过程控制系统的研究一直受到国内外学者的广泛关注,而解耦控制系统则是先进过程控制系统的重要分支。虽然在解耦控制系统设计方面已经取得了许多成果,但是有关多变量时滞过程解耦控制系统设计问题的研究还很不完善。多变量时滞过程继承了无时滞多变量过程的复杂性,且包含的时滞因子使得这种复杂性变得更加难以控制。已有多变量控制方法和单变量时滞过程控制方法大都无法对这类对象实现有效控制。如何针对多变量时滞过程设计先进的解耦控制系统,使其既具有优越的解耦控制性能,又便于被实施应用是一个具有重大理论价值和实际意义的课题。本文在已有的频域解耦技术基础上,利用多变量控制理论和鲁棒控制理论研究了多变量时滞过程解耦控制系统的定量设计问题。通过对已知被控过程模型和控制结构信息进行分析,定量展示出了被控过程包含的耦合和时滞因子对系统性能的不利影响,并进一步解析设计了几类先进的解耦控制系统。这类方法的优点是设计过程简单,控制器参数整定方便。为使系统能够被有效实施,本文还分别为获的的系统推导了稳定性判定条件,发展了控制器参数整定的具体方法。本文的主要创新和贡献如下:1.针对多变量时滞单位反馈控制系统,利用耦合矩阵概念清晰的展示出系统内部耦合特征及过程包含的时滞因子对系统输出性能的影响,并基于该结论发展了一种解耦PID控制器解析设计方法。此外,推导了解耦系统保持稳定性的直观判定条件,根据系统解析设计的特点为获得的解耦PID控制器发展了参数定量整定策略。2.针对多变量时滞单位反馈控制系统,利用有效相对互联分析方法所定量描述的过程内部耦合对过程主对角系统的影响信息,建立了一般多变量时滞过程的有效等价对角传递函数矩阵模型,并在此基础上根据PID控制的频率依赖特性推导了分散PID控制器的解析设计公式。此外,推导了系统保持稳定性的判定条件,发展了控制器参数的整定策略。3.针对多变量时滞过程,通过在典型解耦内模结构中引入一个分散型扰动控制器,建立了一种简单的双自由度解耦内模控制结构,实现了系统设定点跟踪响应和扰动抑制输出响应间的解耦。提出的扰动控制器解析设计新方法,在保证系统输出解耦的前提下,能够明显改善系统的扰动抑制性能。此外,分析并推导了控制系统保持稳定性的判定条件。4.针对积分双输入双输出时滞过程,提出了一种双自由度解耦控制结构。首先提出了一种解析设计解耦器的新方法,实现了对积分双输入双输出时滞过程的完全解耦;其次针对解耦后的积分过程,给出了设定点跟踪控制器和扰动控制器解析设计方法,分析了系统保持稳定性的条件。提出的控制系统有效克服了过程包含的积分项给系统输出带来的不利影响,不但实现了系统设定点跟踪响应和扰动抑制输出响应间的有效解耦,而且能够有效抑制斜坡类型过程输入和输出扰动。5.针对一般非自衡多变量时滞过程,提出一种多自由度解耦控制结构。首先利用多变量时滞过程稳定控制器参数化公式,分别为系统中的多个控制器建立了一般表达式;然后从系统性能优化角度出发推导了各个控制器的具体设计公式。提出的控制系统不但实现了系统设定点跟踪响应和扰动抑制输出响应间的完全解耦,而且实现了对扰动抑制输出响应动态特性的有效调节。更多还原

【Abstract】 The research on advanced process control system continuously receives the domestic and foreign scholars’widespread attention, and decoupling control system is an important branch of advanced process control system. Although a lot of achievements in the development of decoupling control system have been achieved, the research on the decoupling control system design for multivariable processes with multiple time delays is still not perfect. Multivariable processes with multiple time delays inherit the complexities of delay-free multivariable processes, and furthermore, the time delays in processes made these complexities more challenging. The decoupling control methods developed for delay-free multivariable processes and the control methods developed for delayed single-input single-output (SISO) processes can not obtain satisfactory system performance when they are applied directly to multivariable processes with multiple time delays. It has significant theory value and practical significance to develop decoupling control schemes for multivariable processes with multiple time delays, which not only can provide excellent decoupling performance but also can be conveniently applied to practical application.Based on frequency-domain decoupling technology, and using multivariable control theory and robust control theory, this dissertation studied the problem of quantitatively designing the decoupling control systems for multivariable processes with multiple time delays. By analyzing the known information about controlled process and control structure, the negative effects of process interaction and time delays on the system performance are quantitatively depicted, and subsequently, several advanced decoupling control schemes are developed. The dominant merits of the proposed methods are that the design procedure is simple and the tuning of the controller is convenient. In order to achieve the effective implementation of the proposed control schemes, this dissertation also developed the conditions for evaluating the proposed systems’stabilities and the rules for tuning the adjustable parameters of the proposed controllers.The main contributions of this dissertation are as follows:1. For the unity feedback control system of multivariable processes with multiple time delays, the effects of the process’s interaction and time delays on the system outputs are clearly depicted by using the concept of coupling matrix, then a new analytical decoupling PID controller design method is proposed. Besides, the intuitive conditions for evaluating the nominal system stability and the system robust stability are developed, and the rules for tuning the controller’s adjustable parameters are proposed based on the analytical controller design procedure.2. For the unity feedback control system of multivariable processes with multiple time delays, the effective equivalent diagonal transfer matrices are developed for the controlled process by using the quantitative depiction of the interaction effects on the dominant diagonal subsystem of the controlled process that is formed based on the effective relative interaction analysis method, then the analytical design procedure of the decentralized PID controller are given, in which the frequency-dependent property of the interaction are utilized. Besides, this dissertation developed the conditions for evaluating the system stability and the rules for tuning the controller’s adjustable parameters.3. Through adding an additional decentralized disturbance controller into conventional decoupling internal model control structure, a new two-degree-of-freedom decoupling internal model control structure is developed for multivariable processes with multiple time delays. The new structure realized the decoupling between the nominal system set-point tracking responses and the system disturbance rejection responses. The proposed novel disturbance controller design method can achieve remarkable improvement on the performance of disturbance rejection other than the decoupling system outputs. Besides, this dissertation analyzed and developed the conditions for evaluating the system stability.4. A new two-degree-of-freedom decoupling control scheme is proposed for integrating two-by-two systems with multiple time delays. Firstly, a novel inverse-model based decoupler is proposed. This decoupler can realize the effective decoupling between the set-point tracking responses of the nominal system and the system disturbance rejection responses. Subsequently, the analytical design procedures of the set-point tracking controller and the disturbance controller are provided based on the decoupled process. Moreover, the nominal system stability and the robust system stability are analyzed. The new structure can effectively overcome the negative effects of the integrating terms on system outputs, can realize the effective decoupling between the nominal system set-point tracking responses and the system disturbance rejection responses and can effective reject ramp-type disturbances.5. A new multi-degree-of-freedom decoupling control scheme is proposed for general non-self-regulating multivariable processes with multiple time delays. Firstly, the general design formulas of the controllers in this control structure are developed based on the parameterized formulas of the controller that can stabilize general multivariable processes with multiple time delays. Secondly, the detailed analytical design formulas of these controllers are derived from the point of view of optimizing the system performance. This control structure not only can realize the complete decoupling between the nominal system set-point tracking responses and the system disturbance rejection responses but also can tuning the dynamic performance of the disturbance rejection responses.更多还原