双输入双输出时滞过程解耦Smith 控制

针对实际工业过程控制中常见的双输入双输出时滞过程,提出基于Smith预估补偿控制的反向解耦控制器设计方法。通过对系统解耦后的对象采用内模控制思想设计Smith预估控制器,并讨论控制系统对象为一阶加纯滞后（FOPDT）模型下其控制器的实现方法和系统鲁棒稳定性分析。结合实际过程中的模型实例,该解耦控制方案使得系统各路输出响应完全解耦并具有较好的标称性能和鲁棒性。仿真实例验证了该方案的有效性和优越性。     

基于继电辨识的大时滞对象的内模控制

采用改进的饱和继电反馈实验辨识高精度的过程模型，将内模控制与Smith预估控制器相结合，提出了一种适用于大时滞对象的内模控制结构，并按内模控制结构设计控制器。仿真实验表明该控制结构可获得比Smith预估控制更好的动态性能、鲁棒性和抗干扰性能，为大时滞对象的控制提供了一种新的实用方法。     

多变量时滞非方系统的分数阶Smith预估控制

针对多变量时滞非方系统,提出一种基于反向解耦的分数阶Smith预估控制方法.首先,将反向解耦方法推广应用于$m\times n$非方系统中,给出非方解耦矩阵的设计方法,同时为了保证解耦矩阵的稳定正则,给出其实现的必要条件以及条件不满足时的补偿方法;然后,针对解耦后的各个单回路系统设计分数阶Smith预估控制器,根据内模控制与Smith预估控制结构上的等价关系简化控制器的设计,克服时滞环节对系统性能的影响,并且基于最大灵敏度推导出一种控制器参数解析整定方法;最后,通过典型的Shell标准控制问题对所提出方法进行验证.仿真结果表明,反向解耦方法设计简单易于实现,能达到系统完全解耦,控制器参数较少,整定方便,并且具有良好的跟踪能力、抗干扰性和鲁棒性.     

基于TC-ESO的多变量时滞过程控制

工业过程多变量系统大多数具有耦合时滞特性,对此类系统使用常规的解耦方法往往较难控制。使用TC控制器与扩张状态观测器相结合的新型控制策略,降低耦合作用,不加解耦器,简化了系统,有利于工程上实现。将该控制策略与Smith预估器进行比较,仿真研究表明当被控对象时滞参数变化±30%时,系统输出仍然具有较好的特性,证明了该方法对于多变量时滞系统的有效性和可行性。     

多变量时滞系统鲁棒稳定性

基于Smith预估技术和多变量线性系统解耦鲁棒理论,研究了多变量时滞系统鲁棒 稳定性,得到在Smith预估严格匹配时闭环系统稳定,且摄动系统为鲁棒对角优势,则摄动系 统为鲁棒稳定的一般性结论.     

磨煤机制粉系统解耦内模控制器的设计及仿真

本文针对工业过程中常见的多变量时滞耦合输入输出系统,基于内模控制结构提出了一种多变量解耦内模控制设计的方法,该方法设计的内模控制器同时具有解耦器和控制器的作用。其优点是能够实现标称系统输出响应之间的近似或完全解耦,并且改善了系统的大迟延的特性。并与PID对角矩阵解耦设计方法相对比,结果表明：解耦内模控制器设计方法有更好的鲁棒性。     

多变量时滞过程二自由度Smith预估控制方法

针对工业系统中普遍存在的多变量时滞过程,提出了一种二自由度Smith预估控制的方法。通过在被控过程前串联反向解耦矩阵,实现标称系统的完全解耦。在此基础上,运用Dahlin控制算法和内模控制方法,对解耦后的过程分别设计了设定值跟随控制器和干扰抑制控制器,并基于最大灵敏度实现了干扰抑制控制器参数的鲁棒整定。仿真结果表明:该方法设计简单、整定方便,而且具有良好的跟踪特性、抗干扰特性和鲁棒性。     

水厂混凝投药大滞后过程的数据驱动直接控制方法

以自来水厂混凝投药大时滞过程为研究对象,在迭代反馈整定(IFT)方法的基础上,结合Smith预估控制结构,提出了一种混凝投药过程数据驱动直接控制算法.着重针对过程大时滞的特点,在性能指标中加入了预估误差惩罚因子.提出了一种新的步长设置方法,使得步长的下降速率可调.设计了3个闭环实验来求取性能指标梯度向量的无偏估计,完全...     

电厂锅炉燃烧过程控制改进方案及实现

针对锅炉燃烧系统多变量、强耦合、大时滞的复杂特性,提出一种多变量时滞对象的控制方法,以动态风煤比的形式对燃烧过程实施先进控制。所实现的改进的多变量Smith预估算法有效地克服了模型失配对控制的不利影响;多模型智能控制解决了在负荷变化时对象模型的参数不确定性。对某热电厂锅炉燃烧过程的控制结果表明,该方法易于工程实现,适应性强,控制效果优于原DCS系统的PID控制。     

多变量逆解耦自抗扰控制及其在精馏塔过程中的应用

化工生产是一类典型的多变量过程对象,该类对象具有时变性、耦合性、时滞性等特点,传统的单变量控制方法很难在此类系统中取得良好的控制效果.针对时变性,本文在假设对象模型未知的前提下,利用阶跃响应数据,研究了基于最小二乘的一阶、二阶时滞系统辨识方法.针对多变量系统存在耦合性的特点,采用逆解耦方法实现对象的解耦.再对解耦后的时滞子系统设计了自抗扰控制器.仿真实验中,以精馏塔的Wood-Berry模型和Ogunnaike-Ray模型为例,验证了算法的有效性.     

大时延过程的控制方法

有很多工业过程控制系统包含纯时延,克服纯时延是改善时延过程控制质量的一个关键性问题。本文综述自Smith提出的预估控制器以来,近30年内关于解决大时延系统的一系列控制方法。并着重介绍最近几年的研究成果,例如改进型Smith预估控制法;最优控制法;自适应控制法;以及有限谱配置设计方法。借助微计算机实现各种控制算法,可以有效地控制时延系统,论文最后对大时延系统的研究提出了小结和展望。     

System identification in a networked environment using second order statistical properties

System identification for networked control is considered. Due to the time-delays in the network, it can be difficult to work with a discrete-time model and a continuous-time model is therefore chosen. A covariance function based method that relies on the second order statistical properties of the output signal, where it is assumed that the input signal samples are from a discrete-time white noise sequence, is proposed for estimating the parameters. The method is easy to use since the actual time instants when new input signal levels are applied at the actuator do not have to be known. An analysis of the networked system and the effects of the time-delays is made, and the results of the analysis motivate and support the chosen approach. Numerical studies indicate that the method is robust to randomly distributed time-delays, packet drop-outs, and additive measurement noise.     

A note on control of a class of discrete-time stochastic systems with distributed delays and nonlinear disturbances

This paper is concerned with the state feedback control problem for a class of discrete-time stochastic systems involving sector nonlinearities and mixed time-delays. The mixed time-delays comprise both discrete and distributed delays, and the sector nonlinearities appear in the system states and all delayed states. The distributed time-delays in the discrete-time domain are first defined and then a special matrix inequality is developed to handle the distributed time-delays within an algebraic framework. An effective linear matrix inequality (LMI) approach is proposed to design the state feedback controllers such that, for all admissible nonlinearities and time-delays, the overall closed-loop system is asymptotically stable in the mean square sense. Sufficient conditions are established for the nonlinear stochastic time-delay systems to be asymptotically stable in the mean square sense, and then the explicit expression of the desired controller gains is derived. A numerical example is provided to show the usefulness and effectiveness of the proposed design method.     

Delay-dependent guaranteed cost control for T-S fuzzy systems with time delays

This study introduces a guaranteed cost control method for nonlinear systems with time-delays which can be represented by Takagi-Sugeno (T-S) fuzzy models with time-delays. The state feedback and generalized dynamic output feedback approaches are considered. The generalized dynamic output feedback controller is presented by a new fuzzy controller architecture which is of dual indexed rule base. It considers both the dynamic part and the output part of T-S fuzzy model which guarantees that the controller without any delay information can stabilize time-delay T-S fuzzy systems. Based on delay-dependent Lyapunov functional approach, some sufficient conditions for the existence of state feedback controller are provided via parallel distributed compensation (PDC) first. Second, the corresponding conditions are extended into the generalized dynamic output feedback closed-loop system via so-called generalized PDC technique. The upper bound of time-delay can be obtained using convex optimization such that the system can be stabilized for all time-delays whose sizes are not larger than the bound. The minimizing method is also proposed to search the suboptimal upper bound of guaranteed cost function. The effectiveness of the proposed method can be shown by the simulation examples.     

A Novel non-Lyapunov way for detecting uncertain parameters of chaos system with random noises

The paper is concerned with the uncertain parameters and time-delays of chaos system with random noises. A scheme based on differential evolution algorithm (DE) is newly introduced to solve the problem via a nonnegative multi-modal nonlinear optimization, which finds a best combination of parameters and time-delays such that an objective function is minimized. The illustrative examples, in both systems free of time-delays and time-delays systems with random noises, are given to demonstrate the validity of the proposed method.     

不确定时滞Lur''''e型控制系统与时滞相关的绝对稳定性(英文)

研究了一类参数不确定的具有多个时滞的Lur'e型控制系统与时滞相关绝对稳定性问题.通过将原系统变换为等价的奇异系统,利用Moon不等式放大向量积,构造出一个新的Lya-punov-Krasovskii泛函.并由此基于线性矩阵不等式,得到了系统与时滞相关绝对稳定的充分条件.这些充分条件无须预调任何参数矩阵,可以直接运用Matlab软件中LMI工具箱求解.数值例子表明,与现有结果相比,本文结果较大地改进了保证不确定时滞Lur'e型控制系统绝对稳定的时滞界.     

A self-tuning Smith predictor applied to the control of blood pressure: simulation studies

Significant time-delays occur in the response of blood pressure to drug therapy. The classical Smith predictor algorithm used to eliminate such delays is extended here to the principle of self-tuning under mis-match conditions. Two delay-free controller algorithms are investigated, being a self-tuning pole-placement and a self-tuning PID structure. Extensive simulation studies using the well-known Slate model have demonstrated the good transient performance obtained with this self-tuning Smith principle in various combinations, and under realistic variability of patient dynamics.     

不确定时滞Lurie型控制系统与时滞相关的绝对稳定性

研究了一类参数不确定的具有多个时滞的Lur′e型控制系统与时滞相关绝对稳定性问题.通过将原系统变换为等价的奇异系统,利用Moon不等式放大向量积,构造出一个新的Lyapunov-Krasovskii泛函.并由此基于线性矩阵不等式,得到了系统与时滞相关绝对稳定的充分条件.这些充分条件无须预调任何参数矩阵,可以直接运用Matlab软件中LMI工具箱求解.数值例子表明,与现有结果相比,本文结果较大地改进了保证不确定时滞Lur′e型控制系统绝对稳定的时滞界.