On the hyperstability of a class of hybrid systems

Sufficient conditions of the hyperstability of a class of single-input single-output hybrid systems, composed of interconnected continuous and discrete subsystems, are given. Hyperstability is guaranteed by that of a discrete extended system which is built by incorporating samples of the continuous substrate. Asymptotic hyperstability is guaranteed by that of one discrete system, together with that of a continuous one. Both systems are related to an augmented state representation of the linear part of the overall system for all the nonlinear output-feedback time-varying actuators that satisfy generalized Popov-type inequalities.     

Hyperstability of linear time-varying discrete systems

The hyperstability of a class of linear time-varying discrete systems is studied. Sufficient conditions for hyperstability and for stability in the sense of Lyapunov are obtained.     

一种神经元控制模型参考自适应伺服系统

针对存在于摩擦非线性和负载转动惯量时变的伺服系统,提出一种神经元模型参考自适应控制设计方法。导出了控制对象离散数学模型,介绍了伺服系统结构和控制器设计,并用波波夫超稳定性理论证明该系统是渐近超稳定的。仿真结果表明系统具有良好的动态性能、稳态精度和鲁棒性。     

线性混合系统的可观性分析

线性混合系统的控制输入(包括离散控制和连续控制)会影响混合系统的状态可观性．混合系统的可观性包括初始的离散状态和连续状态，以及离散状态的切换时间．对此．分析了系统的控制输入对线性混合系统状态(主要是离散状态)的影响，并论述这将有助于改善某些线性混合系统状态的可观性．通过分析给出了在这种情形下比较宽松的线性混合系统状态可观性条件及其秩检验条件，并给出说明性示例．     

Discrete reachability of hybrid systems

This paper concerns hybrid systems subject to discrete-event supervisory control. It investigates the discrete reachability, where the hybrid system should be moved from a discrete initial state z init into a given discrete goal state z goal by a sequence of discrete inputs. The reachability analysis is carried out in three steps. First, a discrete-event model of the hybrid system is set up. Stochastic automata are used to describe all state sequences which may be generated by the hybrid system. Such a model is called complete. Second, methods for the reachability analysis of stochastic automata are elaborated which concern a weak and a strong condition for reachability. Third, these methods are applied to the hybrid system. It is shown that the reachability of the automaton implies the discrete reachability of the hybrid system, because the model is complete. Therefore, the weak and the strong condition for reachability of the stochastic automaton yield a necessary and a sufficient condition for discrete reachability of the hybrid system.     

Global output feedback sampled‐data stabilization for upper‐triangular nonlinear systems with improved maximum allowable transmission delay

This paper addresses the problem of output feedback sampled‐data stabilization for upper‐triangular nonlinear systems with improved maximum allowable transmission delay. A class of hybrid systems are firstly introduced. The transmission delay may be larger than the sampling period. Then, sufficient conditions are proposed to guarantee global exponential stability of the hybrid systems. Based on these sufficient conditions and a linear continuous‐discrete observer, an output feedback control law is presented to globally exponentially stabilize the feedforward nonlinear system. The improved maximum allowable transmission delay is also given. The results are also extended to output feedback sampled‐data stabilization for lower‐triangular nonlinear systems. Finally, illustrative examples are used to verify the effectiveness of the proposed design methods. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis of discrete model reference adaptive systems

The synthesis of discrete model reference adaptive systems is discussed from the hyperstability point of view. The results included here are an extension of previous results obtained by the author for the continuous case [1].     

Hyperstability and average hyperstability conditions for a broad class of gaussian stochastic systems

The author investigates the hyperstability problem for a broad class of single-control stochastic systems which may be considered as disturbed models of given deterministic systems. The stochasticity comes from the control, which is disturbed by an additive Gaussian noise with its own gain. Hyperstability conditions are given when the noise has a time-independent variance. When this variance depends explicitly upon the time, we define the time-average hyperstability, and conditions for average hyperstability are given. Similar problems are solved for multicontrol Gaussian systems. Illustrative examples show how one can derive from these results a broad class of absolute stability conditions.     

Markov切换系统的随机稳定性分析

根据混合系统离散状态的动态行为和Markov链的状态也是离散的特点,提出了一类离散状态的动态行为是Markov链的混合系统。与传统的混合系统相比,这类系统能够刻画出混合系统离散动态行为的随机性,可以用来描述系统受到外界环境因素制约和内部突发事件等随机因素影响而发生变化的动态行为。根据动态系统的稳定性定义以及随机过程理论,给出了Markov线性切换系统的随机稳定性定义,并且分析了Markov线性切换系统的随机稳定性问题,给出了判定随机稳定性的充分必要条件。     

Design of linear observers for a class of linear hybrid systems

This paper deals with the design of linear observers for a class of linear hybrid systems. Such systems are composed of continuous-time and digital substates and possess, in general, coupling dynamics between both substates. Two observer prototypes based on the prediction error are proposed. The first is based on the observation of an extended discrete system at sampling instants. The discrete extended state is composed of the sampled values of the continuous substate at sampling instants and the digital substate. The estimation of the continuous substate in between sampling instants is made by using the plant parametrization and the sampled prediction error at the preceding sampling instant. The continuous-time state estimates are reinitialized at each new sampling instant by taking values from the corresponding components of the discretized substate of the observer of the auxiliary discrete extended system. The second observer prototype estimates the continuous-time substate for all time from initial conditions which are taken only when the estimation algorithm starts. The observer involves feedback information of the current observation error, that of the preceding sampling instant and that associated with the estimation of the discrete system. As a result, the discontinuities of the estimated substate at sampling instants, which typically occur with the use of the first prototype, are not present in this observation scheme. The exponential convergence to zero of both prediction and observation errors may be ensured under observability and detectability assumptions Furthermore, prescribed pole placement of the state estimation error is achieved under observability of the discrete extended plant. Also, prescribed pole placement of the combined dynamics of the extended plant and observation error can be obtained. For that purpose, the extended hybrid plant is assumed to be controllable when the linear control input is generated from measurements of the state observation. in both observation prototypes.     

混合系统剖析,描述与建模

混合系统是一种离散和连续构件交织的系统。通常以微分方程为连续模型，以离散事件系统或自动机为离散模型。通过分析混合系统的微观结构，文中提出了面向系统设计的描述语言ＤＤＬ。它能直观、精确刻画混合现象，方便设计决策描述，而且通过控制器符号与系统指称约束的延迟，为系统设计带来很大的灵活性。由ＤＤＬ描述的混合系统，经内部通信隐藏和系统单步协调积，可转换为混合变迁系统。     

A generalization of the hyperstability conditions for model reference adaptive systems

A generalization of the hyperstability criterion given in the literature is discussed. The new hyperstability conditions were obtained by utilizing the properties of the positive definite kernels. The results presented here are directly applicable for the synthesis of hyperstable adaptation algorithms for various applications.     

基于混合随机Petri网的一类混合系统的模型及稳定性

混合动态系统是包含离散事件系统（ＤＥＳ）和连续变量系统（ＣＶＳ）的复杂系统。讨论了一类每个离散状态包含一个连续动态系统,且离散事件具有Ｍａｒｋｏｖ链性质的随机混合系统,在提出利用混合随机Ｐｅｔｒｉ网的建模方法的基础上,给出混合均方稳定的概念、稳定性和可镇定条件,最后以一个简单的例子做子说明和仿真。     

基于Popov超稳定性理论的模糊自适应控制器设计方法

对一类常见的非线性系统,利用Popov超稳定性理论得到一种模糊自适应控制方 案,该方案在模型匹配的条件下能保证闭环系统的(渐近)稳定性.当模型匹配条件不满足时, 通过引入一个辅助控制量使系统仍保持稳定.因此,文中提出的方法普遍适用于一类非线性 离散或连续控制系统的设计.     

基于协方差配置的采样估计

在工程应用中,状态估计的指标要求常常表现为误差协方差的形式.在充分考虑系 统内采样特性的基础上,提出了采样估计协方差的定义和一种新的采样估计方法,目的在于 设计离散估计器使采样估计协方差达到指定值,从而获得满意的稳定状态估计性能.将此采 样估计问题等价地转化为一个虚拟离散系统的估计器设计问题,给出了期望估计器的存在条 件及显式表示.数值例子说明了方法的有效性.     

Probabilistic-constrained optimal control of a class of stochastic hybrid systems

Stochastic hybrid systems have several applications such as biological systems and communication networks, but it is difficult to consider control of general stochastic hybrid systems. In this paper, a class of discrete-time stochastic hybrid systems, in which only discrete dynamics are stochastic, is considered. For this system, a solution method for the optimal control problem with probabilistic constraints is proposed. Probabilistic constraints guarantee that the probability that the continuous state reaches a given unsafe region is less than a given constant. In the propose method, first, continuous state regions, from which the state reaches a given unsafe region, are computed by a backward-reachability graph. Next, mixed integer quadratic programming problems with constraints derived from the backward-reachability graph are solved. The proposed method can be applied to model predictive control.     

混合系统建模理论与混合系统模型

在现代工程仿真中,大部分仿真对象表现出同时具有连续和离散对象的特征,利用现有的离散或者连续建模理论不能全面的反应出对象特性,需要对混合系统的建模进行相应的理论研究.从系统理论出发,围绕着系统的连续属性和离散属性,以及他们对系统信息的响应,还有他们之间的相互作用为中心,建立混合系统模型的形式化表达和系统理论基础,并在此基础上建立了混合系统模型.以此模型为基础,在实践中为某大型仿真项目中的工程对象建立了混合模型,在仿真中得到有效的应用.     

冷连轧混合系统中离散事件仿真的建模及关键技术

本文以冷连轧过程仿真为例，分析了混合系统中离散事件的特点以及与连续部分的关 系，对系统进行了层次化分解，讨论了在混合系统仿真过程中对于离散事件部分的建模需要 注意的问题，同时给出了用有限状态机方法实现仿真建模的过程，以及实际应用中的关键技 术．     

基于表面颜色属性的三维模型检索

对基于表面属性的三维模型检索进行研究,提出了基于面积颜色分布、基于球面颜色分布、基于颜色球面调和的三维模型检索方法以及基于表面属性的融合方法.通过对模型表面进行按面积均匀采样来获取其颜色分布信息后形成基于面积颜色分布的特征.通过对模型进行均匀球面采样获取颜色分布信息形成基于球面颜色分布的特征.通过首先将模型表面颜色信息按等经纬度球面采样映射为球面函数,然后对其进行球面调和变换形成颜色球面调和特征.融合特征通过对以上特征的两组或3组依一定权值组合而得到.为验证基于表面属性的三维模型检索方法的效果,建立了一个包含有1171个颜色模型的测试库.实验结果表明以上方法均对基于表面属性的三维模型检索具有较好的检索效果且融合特征可以得到优于任何单一特征的检索效果.