非线性动态系统神经模糊建模与内模/PID双重控制系统设计

非线性动态系统的内模控制要求建立精确的对象正模型和逆模型,这对于大多数实际对象是难以做到.提出了基于一类神经模糊模型的非线性动态系统建模方法,并在此基础上研究了基于神经模糊模型的非线性系统的内模控制设计.基于输入输出数据辨识的对象正模型和逆模型存在着模型失配问题,导致神经模糊内模控制范围变窄和控制鲁棒性降低,为了改善系统的性能,提出了神经模糊内模控制与PID控制结合的双重控制策略.对CSTR的反应物浓度控制研究表明,双重控制策略能有效地拓宽系统可控范围,改善系统性能.仿真结果证明该控制策略简单而有效.     

内模PID控制器在电阻加热炉温控系统中的应用

本文介绍了内模控制(IMC)的基本原理及内模PID控制器的设计方法,进而将这种控制方法应用到电阻加热炉温控系统中.内模PID控制器只有一个可调参数,整定方法简单,克服了常规PID参数整定复杂的缺点,易为工程技术人员掌握.MATLAB仿真结果表明内模PID控制系统具有较好的动态性能和较强的鲁棒性,有效提高了系统的控制品质...     

基于小波网络的非线性内模控制

针对非线性内模控制结构,给出了小波网络逼近系统正、逆模型的充分条件的实现方法。在内模控制结构中引入PID补偿控制,改进了内模控制器的性质。仿真结果表明,小波网络用于非线性内模控制是有效的,内模＋PID控制较单一内模控制具有更快速和平稳的跟踪性能。     

液位控制的模糊内模PID控制器设计

本文介绍了液位过程模糊内模PID控制器的设计.利用机理分析和实验辨识相结合的方法建立了被控过程的数学模型,并依据内模控制原理设计了一种PID控制器,该控制器结构简单,只有一个可调参数.为了克服了内模控制器参数整定要在系统标称性能和鲁棒性之间进行折衷选择的局限性,利用模糊逻辑实现了控制器参数的在线自动整定.实验结果表明,模糊内模PID控制器能有效地改善系统的性能.     

二阶时滞工业系统的自调整模糊内模PID控制

基于内模控制理论,针对二阶时滞工业系统,设计了模糊内模PID控制方案.该方案实现简单,且对工况的变化具有优良的适应性.对某典型的时滞工业过程的三种不同工况进行二阶建模与仿真,结果表明,该控制方案,超调小,过渡时间短,动态性能好,控制效果优于内模控制及PID控制.     

内模控制在温度控制传感器系统中的应用

为了适应现实状况对于提高控制效果的要求,对温度控制传感器系统采用了内模控制方法,完成基于内模控制的温度控制系统设计.针对具有大时滞的温度控制对象完成基于内模控制的温度控制系统设计;对相同的大时滞温度控制对象,完成基于PID控制的温度控制系统设计,并在Matlab/Simulink仿真平台上对所设计的温度控制系统进行仿真分析.仿真结果表明了内模控制滤波器的时间常数对系统控制效果的影响规律,其控制效果优越于PID控制.     

锅炉过热蒸汽压力控制系统设计与实现

针对工业过程中具有大惯性、大滞后和模型参数时变等特性的蒸汽出口压力系统,采用常规PID控制方法,往往无法得到满意的控制效果.为此,提出采用三自由度内模控制-模糊自适应PID算法,通过最小二乘原理辨识主蒸汽压力对象的内部模型,实现对蒸汽出口压力系统的串级控制.该控制系统融合了模糊控制、内模控制、PID控制3种方法的特点,程序设计简单,便于工业应用.通过仿真和PCS7实验表明,该方案增强了系统抗干扰能力和鲁棒性能,改善了系统的控制品质.     

基于分数阶内模控制的风力机叶片颤振研究

针对风力机叶片颤振系统,提出了一种结合分数阶(Fractional Order)控制与内模控制(Internal Model Control,IMC)的新型颤振控制方法.利用分数阶滤波器设计了分数阶内模控制器,基于闭环动态特性指标,如相位裕量和截止频率,实现对控制器参数的自整定.通过仿真实验对比证明,针对风力机叶片颤振控制,所设计的控制方法优于传统PID、内模PID控制方法,不仅减少了控制参数,而且提高了动态特性和鲁棒性.     

内模控制在过程控制系统中的应用研究

内模控制是一种简单、实用的先进控制算法,是研究其它基于模型的控制策略的理论基础.本文介绍了内模控制的基本原理及内模控制器的设计方法,基于过程控制实验系统,采用内模控制策略对其进行控制,并在相同状况下,采用常规PID和内模PID算法对其进行控制比较.结果表明,采用内模控制策略的控制系统在超调量、上升时间和调节时间等方面均有所减小和缩短,体现了内模控制的实用性和控制效果的优越性,对于内模控制在其它领域的应用具有一定的参考价值.     

基于IMC原理的电子节气门控制策略

发动机系统中的电子节气门是一种典型的非线性控制对象,特别是节气门运动过程中的弹簧扭矩和摩擦阻力十分复杂,其数学模型很难精确建立,参数不易获取.针对电子节气门的非线性因素,提出一种内模控制器的设计方法.首先分析电子节气门系统的数学模型,在Matlab/Simulink仿真平台上对模型的有效性进行验证,进而以内模控制结构为基础,建立电子节气门复域模型,分析系统的非线性干扰,设计针对时变参数的内模控制器.仿真结果显示,在模型较精确的情况下,内模控制器具有优于传统PID和一般滑模控制的控制性能,而在模型失配的情况下,内模控制器的鲁棒性能够保证它的控制性能仍然优于传统PID.在所提出的内模控制器设计方法中,前馈滤波器的设计并未用到任何系统参数,但仍然能够保证理想的稳态响应和扰动响应,因此所提出方法相比于很多针对具体模型的控制策略,具有更好的实用价值.     

Experimenting with dynamic linking with ADA

An approach to achieving dynamic reconfiguration within the framework of Ada¹ is described. A technique for introducing a kernel facility for dynamic reconfiguration in Ada is illustrated, and its implementation using the Verdix VADS 5.5 Ada compiling system on a Sun3–120 running the 4.3 BSD Unix operating system is discussed. This experimental kernel allows an Ada program to change its own configuration dynamically, linking new pieces of code at run-time. It is shown how this dynamic facility can be integrated consistently at the Ada language level, without introducing severe inconsistencies with respect to the Standard semantics.     

Model-checking timed automata with deadlines with Uppaal

Timed automata with deadlines (TAD) are a form of timed automata that admit a more natural representation of urgent actions, with the additional advantage of avoiding the most common form of timelocks. We offer a compositional translation of a practically useful subset of TAD to timed safety automata (the well-known variant of timed automata where time progress conditions are expressed by invariants). More precisely, we translate networks of TAD to the modeling language of Uppaal, a state-of-the-art verification tool for timed automata. We also describe an implementation of this translation, which allows Uppaal to aid the design and analysis of TAD models.     

Computing with words and its relationships with fuzzistics

Words mean different things to different people, and so are uncertain. We, therefore, need a fuzzy set model for a word that has the potential to capture their uncertainties. In this paper I propose that an interval type-2 fuzzy set (IT2 FS) be used as a FS model of a word, because it is characterized by its footprint of uncertainty (FOU), and therefore has the potential to capture word uncertainties. Two approaches are presented for collecting data about a word from a group of subjects and then mapping that data into a FOU for that word. The person MF approach, in which each person provides their FOU for a word, is limited to fuzzy set experts because it requires the subject to be knowledgeable about fuzzy sets. The interval end-points approach, in which each person provides the end-points for an interval that they associate with a word on a prescribed scale is not limited to fuzzy set experts. Both approaches map data collected from subjects into a parsimonious parametric model of a FOU, and illustrate the combining of fuzzy sets and statistics—type-2 fuzzistics.     

基于UML MARTE处理AADL的端到端流延迟

AADL和MARTE都支持对实时嵌入式系统形式化建模的分析。利用MARTE的时间模型设备,研究MARTE是如何对实时嵌入式系统的建模和分析的,能够比较准确的通过事件或者数据端口的端到端流延迟分析,表达AADL周期性或非周期性任务。     

Image steganalysis with entropy hybridized with chaotic grasshopper optimizer

We propose a hybrid grasshopper optimizer to reduce the size of the feature set in the steganalysis process using information theory and other stochastic optimization techniques. This paper results from the stagnancy of local minima and slow convergence rate by the grasshopper algorithm in optimization problems. Therefore, we enhance the grasshopper optimization (GOA) performance with chaotic maps to make it Chaotic GOA (CGOA). Then, we combine the CGOA with adaptive particle swarm optimization (APSO) to make it Chaotic Particle-Swarm Grasshopper Optimization Algorithm (CPGOA). Next, we use the proposed optimizer with entropy to find the best feature subset of the original Subtractive Pixel Adjacency Model (SPAM) and Spatial Rich Model (SRM) feature set. Finally, the proposed technique is experimented with to detect the spatial domain steganography with different embedding rates on the BOSSbase 1.01 grayscale image database. The results show the improved results from the proposed hybrid optimizer compared to the original GOA and other state-of-the-art feature selection methods in steganalysis.

     

Uncertainty management with imprecise knowledge with application to design

Uncertainty management is critical to the effective use of knowledge-based systems in a wide variety of domains. Design is typical of these domains in that the implementation of a design in an artifact, the future environment for the artifact, and the component characteristics of the artifact are all uncertain. Existing probabilistic schemes to address the inherent uncertainty in areas like design assume precise knowledge of the probabilities of relevant events. This paper defines a probabilistic method for uncertainty management with imprecise inputs. The approach combines Bayesian inference networks and information theoretic inference procedures. The resulting scheme manages both imprecision and uncertainty in the problem domain. An application of the approach to materiel design is described.     

使用双缓存来解决GDI下的闪烁问题

在图形图像处理过程中，当显示绘制的图像时，有时会出现闪烁的情况。本丈从窗口、视口、坐标系统的基本概念和关系出发，主要讲解了如何使用双缓存来解决GDI下的闪烁问题。此方法已经应用于项目地质资料解释系统中对井曲线的修改和显示部分，实践证明，这种方法是可行的。     

Games with forbidden situations. Models with soft constraints

The methods of modeling conflict situations are systematized and illustrated, in which the possibilities of each of the sides can depend on the actions of partners. Conflicts are considered in which the disturbance of constraints is possible, but undesirable for one or a few players.     

Modelling Calculi with Name Mobility using Graphs with Equivalences

In the theory of graph rewriting, the use of coalescing rules, i.e., of rules which besides deleting and generating graph items, can coalesce some parts of the graph, turns out to be quite useful for modelling purposes, but, at the same time, problematic for the development of a satisfactory partial order concurrent semantics for rewrites. Rewriting over graphs with equivalences, i.e., (typed hyper)-graphs equipped with an equivalence over nodes provides a technically convenient replacement of graph rewriting with coalescing rules, for which a truly concurrent semantics can be easily defined. The expressivity of such a formalism is tested in a setting where coalescing rules typically play a basic role: the encoding of calculi with name passing as graph rewriting systems. Specifically, we show how the (monadic fragment) of the solo calculus, one of the dialect of those calculi whose distinctive feature is name fusion, can be encoded as a rewriting system over graph with equivalences.