基于解耦的球磨机系统动态矩阵控制

针对制粉系统球磨机的多变量强耦合特性,提出基于逆向解耦的动态矩阵控制设计方法,先将球磨机系统分解为三个单输入单输出系统,然后利用基于对象阶跃响应的动态矩阵控制算法,对解耦后的广义系统进行了仿真研究.结果表明,逆向解耦能有效地解除变量间的强耦合和大时延问题,并且动态矩阵预测控制算法控制效果明显,优于传统的PID控制,具有实时性强、计算速度快和抗干扰能力好等优点.     

基于改进的PSO算法的球磨机PID神经网络控制系统

球磨机制粉系统是一个复杂的多变量系统,具有强耦合、非线性、大迟延、慢时变等特点,很难建立精确的数学模型,采用常规的控制策略难以获得满意的控制效果。针对上述问题,在对球磨机制粉系统动态特性进行分析的基础上,提出了一种不依赖于被控对象数学模型的多变量PID神经网络解耦控制策略;为进一步提高控制器性能,利用一种改进的PSO算法对PID神经网络的权值初值进行离线优化训练,然后采用BP算法对权值进行在线调整,避免网络陷入局部极小值,保证了系统不会出现大的超调和震荡。仿真结果表明,该策略可以保证球磨机控制系统有大范围的鲁棒性和适应性,能较好地解决球磨机制粉系统的耦合性、时变性等问题,具有优良的解耦机制和控制品质。     

球磨机制粉系统参数自整定PID解耦控制器

针对球团厂钢球磨煤制粉系统具有多变量强耦合、时滞、非线性以及生产工况变化大的复杂性,已有的控制方法难以满足其控制要求的现状,以磨煤机的数学模型为依据,提出了一种新型的多变量PID解耦控制策略.该控制系统由比例因子模糊自整定单元、PID控制器和基于对角矩阵法的解耦补偿器组成;PID控制器参数由粒子群算法进行优化.仿真结果表明,所建模型和所提控制方法的有效性.该方法可在大范围内解决系统的非线性和强耦合问题,具有较强的鲁棒性和运行工况适应性.     

钢球磨中储式制粉系统的建模与控制

钢球磨煤机中间储仓式制粉系统具有多变量强耦合、强非线性、工况变化大的特性，长期以来难以投入自动控制，因此成为电力行业自动控制研究的热点问题。详细研究和分析了球磨机制粉系统的工作原理及工作特点，对钢球磨中储式制粉系统的数学模型和实现自动控制的技术方案进行了比较全面的综述，对各控制方法的优缺点、适用性、控制效果等等进行了详细地分析和比较，并指出多变量智能解耦控制技术是解决该系统自动控制的有效手段。     

多变量解耦控制系统设计与仿真

工业生产过程中,被控系统越来越复杂,需要控制的变量通常不止一对,而且相互耦合,较成熟的线性多变量控制理论与设计方法已难以满足实际的多变量生产过程控制。本文针对多变量强耦合带有延迟环节的被控系统,研究了一种简化的串联前馈补偿解耦控制器设计方法。根据被控对象的辨识模型,设计串联前馈补偿解耦器,使系统解耦成单输入单输出模型,进而分别对解耦后输入输出模型设计PID控制器,整定PID控制器参数。仿真结果表明该方法具有较好的解耦能力和鲁棒性,算法简单,易于实现。     

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。     

多变量解耦控制系统设计与仿真北大核心CSCD

工业生产过程中,被控系统越来越复杂,需要控制的变量通常不止一对,而且相互耦合,较成熟的线性多变量控制理论与设计方法已难以满足实际的多变量生产过程控制。本文针对多变量强耦合带有延迟环节的被控系统,研究了一种简化的串联前馈补偿解耦控制器设计方法。根据被控对象的辨识模型,设计串联前馈补偿解耦器,使系统解耦成单输入单输出模型,进而分别对解耦后输入输出模型设计PID控制器,整定PID控制器参数。仿真结果表明该方法具有较好的解耦能力和鲁棒性,算法简单,易于实现。     

基于SVM逆方法的球磨机制粉系统预测控制

根据球磨机制粉过程的特点及相应的动态数学模型,证明了系统的可逆性.进一步利用支持向量机(SVM)对非线性系统具有良好逼近能力的特性,通过其来辩识球磨机制粉过程的逆系统,可以很好解决球磨机制粉系统逆系统建模难的问题,将该逆模型与原系统串联可构成解耦后的伪线性复合系统.同时为了克服逆系统的建模误差,通过设计预测控制器对该复...     

循环流化床锅炉双模糊解耦控制的研究

针对循环流化床锅炉多参数、非线性、时变、强耦合的特点,引入了一种新型的模糊解耦算法,依据解耦补偿原理和模糊控制思想,提出了以模糊控制器作为解耦补偿器,以模糊PID作为系统控制器的双模糊解耦控制方法。以耦合最严重的燃烧系统为研究对象,通过相对增益确定多变量的耦合程度,并配对合适的输入输出变量。利用模糊控制器不要求被控对象精确的数学模型,适合于强耦合、大滞后等优点,有效地减少了系统动态响应时间,提高了实时性和控制精度。仿真结果表明,本文提出的控制策略简单可行、效果良好。     

单元机组协调控制系统控制策略研究

针对单元机组协调控制系统多变量、强耦合、时变、滞后大的特点,提出一种采用串联后补偿单向解耦后加入PID控制器自整定的控制策略.该控制策略首先对系统进行串联后补偿实现完全解耦,并通过单向解耦对解耦系统进行简化,然后把多变量的控制问题转化为多个单变量,再对各个单变量加入PID控制器进行自整定.通过对125 MW单元机组协调控制系统的仿真分析可知,这种方法有效消除了输入与输出之间的强耦合带来的不利影响,使系统输出稳定,控制效果好.     

混合关系中的函数依赖及其相关规则

在实际应用中有这样一类关系数据库,其中数据项在某个属性上的取值本身又是一个关系。讨论这种混合关系中的函数依赖及其相应的相关规则具有一定的理论意义和实际应用价值。给出这种混合关系的形式定义、混合关系中4种类型的函数依赖关系以及相应的4种类型的相关规则;并给出混合关系到一般关系的转换,通过这个转换说明了混合关系与普通关系的联系及其差别。给出一个实际应用中的例子,来说明混合关系中的函数依赖和相关规则的形式多样性。     

Fault tolerant control for joint structure in PEMS high speed maglev train

The PEMS high speed maglev train, which features a permanent magnet inside an electromagnet, is a new kind of maglev train for long distance intercity transportation. The joint structure, which consists of two single levitation sub‐systems, is the fundamental levitation unit. Two kinds of faults are considered and corresponding fault tolerant control strategies are proposed. The first fault condition is when a gap sensor that is part of a single levitation system is faulty. For this kind of fault, a fault tolerant control strategy based on signal reconfiguration is proposed. The second fault condition is when the whole of a single levitation sub‐system is faulty. Under this condition, a faulty model is firstly established, then a fault tolerant control strategy is designed. When this kind of fault is detected, a switch from the normal controller to the fault tolerant controller can make the faulty system stable.     

Using genetic algorithm for lot sizing and scheduling problem with arbitrary job volumes and distinct job due date considerations

This paper considers an integrated lot sizing and scheduling problem for a production–distribution environment with arbitrary job volumes and distinct due dates considerations. In the problem, jobs are firstly batch processed on a batching machine at production stage and then delivered to a pre-specified customer at the subsequent delivery stage by a capacitated vehicle. Each job is associated with a distinct due date and a distinct volume, and has to be delivered to the customer before its due date, i.e. delay is not allowed. The processing time of a batch is a constant independent of the jobs it contains. In production, a constant set-up time as well as a constant set-up cost is required before the first job of this batch is processed. In delivery, a constant delivery time as well as a constant delivery cost is needed for each round-trip delivery between the factory and the customer. Moreover, it is supposed that a job that arrives at the customer before its due date will incur a customer inventory cost. The objective is to find a coordinated lot sizing and scheduling scheme such that the total cost is minimised while guaranteeing a certain customer service level. A mixed integer formulation is proposed for this problem, and then a genetic algorithm is developed to solve it. To evaluate the performance of the proposed genetic algorithm, a lower bound on the objective value is established. Computational experiments show that the proposed genetic algorithm performs well on randomly generated problem instances.     

Generalized theory of uncertainty (GTU)—principal concepts and ideas

Uncertainty is an attribute of information. The path-breaking work of Shannon has led to a universal acceptance of the thesis that information is statistical in nature. Concomitantly, existing theories of uncertainty are based on probability theory. The generalized theory of uncertainty (GTU) departs from existing theories in essential ways. First, the thesis that information is statistical in nature is replaced by a much more general thesis that information is a generalized constraint, with statistical uncertainty being a special, albeit important case. Equating information to a generalized constraint is the fundamental thesis of GTU. Second, bivalence is abandoned throughout GTU, and the foundation of GTU is shifted from bivalent logic to fuzzy logic. As a consequence, in GTU everything is or is allowed to be a matter of degree or, equivalently, fuzzy. Concomitantly, all variables are, or are allowed to be granular, with a granule being a clump of values drawn together by a generalized constraint. And third, one of the principal objectives of GTU is achievement of NL-capability, that is, the capability to operate on information described in natural language. NL-capability has high importance because much of human knowledge, including knowledge about probabilities, is described in natural language. NL-capability is the focus of attention in the present paper. The centerpiece of GTU is the concept of a generalized constraint. The concept of a generalized constraint is motivated by the fact that most real-world constraints are elastic rather than rigid, and have a complex structure even when simple in appearance. The paper concludes with examples of computation with uncertain information described in natural language.     

Distributed self-healing control in SONET

This paper proposes a distributed self-healing architecture which contains two self-healing techniques. In this proposal, a path restoration by Self-Healing Ring (SHR) and a path restoration by Dynamic Self-Healing (DSH) algorithm are jointly applied in a network. In the architecture, SHR is applied for a part of a path which is terminated by an Add-Drop Multiplexer (ADM), and DSH is applied for another part of a path which is terminated by two Digital Cross-Connect Systems (DCSs). Based on the architecture, DSH can be applied for a part of a path which is terminated by an ADM. Next, a network design algorithm is described in order to optimize the amount of spare capacity. As a result, spare capacity reduction is realized by using the algorithm for a network where the proposed architecture is applied.     

基于通用比较模型的t-可诊断系统的特征化及并行诊断算法

文中介绍了一种系统级故障诊断模型－－通用比较模型,该模型处理器作为自身的比较器,综合经典的ＰＭＣ模型和Ｍａｅｎｇ／Ｍａｌｅｋ模型的优点,基于该报多处理器系统的ｔ＿可诊断性问题,给出了ｔ＿可诊断系统的特征化,证明了一个系统成为ｔ－可诊断系统的新的充分必要条件,其次,证明在通用比较模型中,确定故障顺集的问题等价于求解一个超图的最小横切集（Ｍｉｎｉｍｕｍ ｔｒａｖｅｒｓａｌ）,该超图是根据多处理器的通信     

辨识非线性曲线的非线性极大似然—优化法

工程上经常碰到非线性曲线辨识问题。本文探讨一种非线性极大似然-优化法并结合三次样条函数拟配法,形成统一的逐次逼近的直接辨识非线性曲线的非线性辨识方法。该法兼有极大似然法的唯一性、很好的收敛性和优化法直接处理非线性系统的能力,辨识出的样条函数曲线能无限地光滑地逼近非线性曲线。     

基于角色和范围的通用管理系统的设计与实现

用户管理系统是Web应用系统及大型软件系统的重要组成部分。在目前已有的用户管理系统中,角色只是权限的集合,不涉及管辖范围,是一个一维空间上的概念。该文提出一种二维角色的概念,是由权限和范围组成的二元对集合,是一个二维空间上的概念。构建一个基于二维角色的通用用户管理模型,设计一个通用用户管理系统,能满足现代Web应用系统和大型软件系统对用户授权的多层次和多空间的要求。     

Towards the optimal control of Markov chains with constraints

An optimal control problem with constraints is considered on a finite interval for a non-stationary Markov chain with a finite state space. The constraints are given as a set of inequalities. The optimal solution existence is proved under a natural assumption that the set of admissible controls is non-empty. The stochastic control problem is reduced to a deterministic one and it is shown that the optimal solution satisfies the maximum principle, moreover it can be chosen within a class of Markov controls. On the basis of this result an approach to the numerical solution is proposed and its implementation is illustrated by examples.     

Vague集的模糊逼近与模糊熵

给出了vague集转换为模糊集的一种新的方法,定义了vague集的模糊逼近。利用vague集的模糊逼近研究了vague集的模糊熵及其相关性质。