大滞后系统的Smith在线辨识预估控制的研究

工业过程中普遍存在大时滞对象,为解决大滞后复杂系统因无法建立精确数学模型而难于控制的问题,将史密斯(Smith)预估控制原理和在线辨识方法结合起来,在Smith预估控制系统中,用系统辨识的模型代替传统预估补偿模型,根据最小二乘辨识算法辨识模型的各个参数,提出了Smith在线辨识预估控制算法;针对二阶加纯滞后对象在滞后时间有/无建模误差进行了仿真研究。研究结果表明,Smith在线辨识预估控制的性能指标和鲁棒性有很大的改善。     

Research on large time-delay system based on online identification of Smith predictive control

工业过程中普遍存在大时滞对象,为解决大滞后复杂系统因无法建立精确数学模型而难于控制的问题,将史密斯(Smith)预估控制原理和在线辨识方法结合起来,在Smith预估控制系统中,用系统辨识的模型代替传统预估补偿模型,根据最小二乘辨识算法辨识模型的各个参数,提出了Smith在线辨识预估控制算法;针对二阶加纯滞后对象在滞后时间有/无建模误差进行了仿真研究.研究结果表明,Smith在线辨识预估控制的性能指标和鲁棒性有很大的改善.     

Fuzzy-Smith控制器在pH值控制中的应用

针对油田污水pH处理系统具有的大惯性、纯滞后、非线性等特点,文章采用模糊控制和Smith预估控制相结合的控制方法.仿真结果表明此种控制方法动态性能良好,且具有较强的鲁棒性和抗干扰能力.     

一种新的控制方法在主汽温控制中的应用研究

针对电厂中主汽温控制系统具有大滞后，非线性的特点,提出了一种基于Smith预估器的单神经元PSD自适应控制算法．即由Smith预估器和单神经元PSD自适应控制器组合的复合控制。仿真结果表明,这种控制方式具有较好的自适应性和鲁棒性。     

纯滞后系统的Smith预估器算法

大滞后大惯性对象的控制一直是理论上得到重视但又没有得到充分解决的问题。Smith预估器是用于大滞后犬惯性对象的有效设计方法．但是在传统的控制方式中要得到应用的限制很多。本文在对系统的稳定性和动态性能分析的基础上．提出了一种简单实用的Smith预估器的控制算法。理论分析和仿真计算表明．该方法能使闭环系统具有较好的动态性能和稳定性。     

Smith预估器与观测器结合的补偿控制在时滞系统中的应用

在工业过程中,控制的对象通常具有滞后环节。对于大滞后的被控对象而言,Smith预估补偿控制可以提供很好的控制品质,但前提是必须提供精确的数学模型。为了解决模型失配时Smith预估控制效果不理想这一问题,文章提出了Smith预估器与状态观测器结合的补偿控制策略,通过Smith预估器抵消闭环特征方程中出现的时滞项,利用状态观测器提高了系统的响应速度和系统的稳定性,仿真结果表明该方法的有效性。     

基于Smith预估器的温控系统设计与仿真

本文针对温控系统的大时滞特性,提出了基于Smith预估控制的设计方法。对Simulink仿真和常规PID控制方法进行比较,分析了Smith预估控制在模型参数发生变化时的系统性能。仿真结果表明,Smith预估控制具有很好的鲁棒性,可以改善系统的动态性能,提高控制品质。     

基于Smith模糊PID控制算法的炉温控制系统

针对电加热炉温度控制系统,研究了Smith模糊PID复合控制方法.该控制方法利用Smith预估算法克服纯滞后,利用模糊控制来提高系统的鲁棒性,利用PID控制来提高稳态精度.在模型匹配和失配情况下进行了仿真研究,结果表明复合式控制器具有良好的稳定性和鲁棒性.实际运行结果也表明,对于大时间滞后的电加热炉温控系统是一种实用而简便的控制方法.     

纯滞后系统的动态矩阵预测控制算法研究

介绍了动态矩阵预测控制算法,结合具有纯滞后环节的单容水箱系统进行仿真,并与传统PID控制、Smith预估补偿控制以及Dalin算法进行比较,研究表明,针对纯滞后系统的DMC预测控制具有更好的控制品质,值得进一步推广研究。     

大纯滞后系统的模糊-Smith控制及参数优化

分析了采用常规Smith预估器的大纯滞后系统控制性能不佳的原因以及常规模糊控制的不足，研究一种适合大纯滞后系统的改进的模糊-Smith控制器，并用遗传算法对其参数进行寻优。仿真实验表明，改进的模糊-Smith控制器具有很好的品质特性和良好的鲁棒性。     

Improving performance using cascade control and a Smith predictor

Many investigations have been done on tuning proportional-integral-derivative (PID) controllers in single-input single-output (SISO) systems. However, only a few investigations have been carried out on tuning PID controllers in cascade control systems. In this paper, a new approach, namely the use of a Smith predictor in the outer loop of a cascade control system, is investigated. The method can be used in temperature control problems where the secondary part of the process (the inner loop) may have a negligible delay while the primary loop (the outer loop) has a time-delay. Two different approaches, including an autotuning method, to find the controller parameters are proposed. It is shown by some examples that the proposed structure as expected can provide better performance than conventional cascade control, a Smith predictor scheme or single feedback control system.     

基于结构改进Smith预估单神经元PSD的长时延NCS研究

针对长时延网络控制系统（NCS）中存在时延和被控对象等问题,提出了一种新型结构改进Smith预估单神经元PSD控制器.新型控制器由结构改进Smith预估器和单神经元PSD控制器组成,结构改进Smith预估器通过对传统Smith预估器模型结构上的改进,避免了建立网络时延的预估模型,无需对网络时延进行在线测量、估计或辨识,补偿了网络时延对系统的性能带来的影响;单神经元PSD控制器解决了结构改进Smith预估器的模型失配问题,通过Matlab环境下的TrueTime工具箱对NCS进行仿真实验,并对传统PID控制方法、结构改进Smith预估PID控制方法和结构改进Smith预估单神经元PSD控制方法进行了仿真比较.研究结果表明,该新型控制器有效地补偿了网络时延对NCS的性能带来的影响,在模型失配情况下具有良好的鲁棒性和适应性,是对长时延NCS-种可行且有效的控制方法.     

Sensitivity analysis of systems with a cascade compensator embedded in a Smith predictor to dead-time variation

This paper considers the use of a cascade compensator embedded in a Smith predictor in the forward path of a system being designed, which is an effective way to solve two problems: providing the desired process performance in the system and placing the dead-time element outside the closed loop so that it only increases the transient time by the value of the time delay and does not affect the overshoot value. It is shown that the Smith predictor should be used with caution because, being based on an additive signal compensation scheme, it may be not robust and may require accurate knowledge of the time-delay value for robust implementation. The problem of sensitivity analysis of the system to dead-time variation is stated and solved.     

Enhancing the performance of parallel cascade control using Smith predictor

Parallel cascade controllers are used in chemical processing industries to improve the dynamic performance of a control system in the presence of disturbances. In the present work, a delay compensator has been incorporated in the primary loop of the parallel cascade control system. The secondary controller is designed using the internal model control (IMC) method. The primary controller is designed based on a direct synthesis method for the delay-free system. Design of controllers for slow (when the secondary loop dynamics is slow i.e. process contains poles sufficiently slower than the desired closed loop response) as well as fast dynamics (when the inner loop dynamics is fast i.e. process contains poles sufficiently faster than the desired closed loop response) of the secondary process is considered. The method provides robust control performances. Significant improvement in the closed loop performances are obtained with the delay compensator over that of a conventional parallel cascade control system. Several case studies are considered to show the advantage of the proposed method when compared to other recently reported methods.     

阳极焙烧排烟架的模糊PID复合控制

阳极焙烧系统是一个具有耦合、大时滞、非线性的控制系统,其中排烟架是阳极焙烧系统的重要组成部分。针对系统存在的滞后及时变问题,该文采用稳态、动态性能较好的复合模糊控制器对其进行控制。通过仿真及运行的结果可以表明,复合模糊控制效果明显优于传统的PID控制,提高了控制系统的稳定性和鲁棒性。     

带积分的模糊Smith预估器在电加热温度控制中的应用

传统的smith预估器是解决大纯滞后系统控制的有效方法,但它依赖于被控对象精确的数学模型,使应用受到了限制。带积分的模糊smith预估器兼有前者的特性,又不依赖于对象精确的数学模型,且有较强的鲁棒性。论文给出了设计方法及在电加热炉中的应用结果。     

Digital redesign of analog smith predictor for systems with input time delays

This paper presents a new methodology for digitally redesigning an existing analog Smith predictor control system, such that the cascaded analog controller with input delay can be implemented with a digital controller. A traditional analog Smith predictor system is reformulated into an augmented system, which is then digitally redesigned using the predicted intersampling states. The paper extends the prediction-based digital redesign method from a delay free feedback system to an input time-delay cascaded system. A tuning parameter v is optimally determined online such that in any sampling period, the output response error between the original analogously controlled time-delay system and the digitally controlled sampled-data time-delay system is significantly reduced. The proposed method gives very good performance in dealing with systems with delays in excess of several integer sampling periods and shows good robustness to sampling period selection.     

基于负载观测器的PMSM分数阶滑模位置控制

针对永磁同步电机位置控制系统,设计分数阶滑模变结构控制器,以代替传统PID三闭环串级控制结构的转速环和位置环控制器。针对电机运行时负载转矩会受到外界干扰的问题,设计负载转矩观测器。仿真结果表明分数阶滑模控制器有良好的动态和稳态性能以及良好的鲁棒性。     

大时间热响应常数投影物镜超高精度温度控制

为满足高分辨率光刻机控制大时间热响应常数投影物镜温度时响应速度和超高精度的要求,设计了前馈—串级水冷投影物镜温控系统。该系统以物镜为主控对象、冷却循环水为副控对象。针对物镜的慢动态温度变化特征,采用模型预测控制作为外环主控制算法;针对冷却水远传回路的纯时滞特性,采用带Smith预估器的PID控制作为内环副控制算法;为解决光刻机在不同工况下激光光路对物镜温度的严重扰动,引入前馈补偿控制激光热扰动。最后,在不同控制结构和热干扰条件下,进行了模拟物镜温度控制实验。结果显示,物镜温度稳态误差曲线在±0.01 ℃内波动。实验证明该系统极大地提高了物镜的温度收敛速度,具有较强的抗干扰能力,能满足物镜的超高精度温度控制要求。