双线性系统可控性综述

双线性系统是一类特殊的非线性系统,广泛存在于现实世界中,如工程、经济、生物、生态等领域,被认为是最接近于线性系统的非线性系统．对双线性系统的研究已历经了近半个世纪. 作为系统最基本的属性,双线性系统可控性的研究一直以来是热点和难点.本文分别对连续双线性系统可控性和离散双线性系统可控性进行讨论, 综述了双线性系统可控性的研究.特别地,报告了近来对离散双线性系统可控性研究的新成果.最后,例举了一些可控的双线性系统例子.     

Reliability and Mean Time to Failure of Unrepairable Systems With Fuzzy Random Lifetimes

In practice, the lifetimes of unrepairable systems contain both randomness and fuzziness. So it is appropriate to assume the lifetimes of systems to be fuzzy random variables. In this paper, the definitions of reliability and mean time to failure (MTTF) of unrepairable systems with fuzzy random lifetimes are given, respectively. Then basic mathematical models of unrepairable systems with fuzzy random lifetimes are established. Furthermore, the reliability and MTTF of series systems, parallel systems, series-parallel systems, parallel-series systems, and cold standby systems are discussed, respectively. Finally, some numerical examples are presented to illustrate how to calculate the reliability and MTTF of unrepairable systems with fuzzy random lifetimes.     

Consensus recovery of multi-agent systems subjected to failures

Consensus recovery is one of the most important topics of multi-agent systems subjected to failures, but there are few literatures considering this theme. In this article, two disastrous failures are introduced and corresponding recovery programs are proposed to investigate the consensus recovery of multi-agent systems. The failures of multi-agent systems mainly refer to the failures to the agents and links. The cut-agent and cut-link are presented to better understand the disastrous failures of multi-agent systems, and they are the most important components of multi-agent systems. When the cut-agent and cut-link are removed from the systems, the multi-agent systems will become disconnected, and the neighbour agents of cut-agent are used to recover the consensus of multi-agent systems in this article. For different failures, the different measures are taken to restore the connectivity of multi-agent systems, so as to recover the consensus of multi-agent systems. Under the proposed recovery strategies, the convergence speed of achieving consensus of the resulting networks is considered as the main target. Moreover, there is a trade-off between the convergence speed and robustness of the resulting networks.     

闭环系统故障诊断技术综述

本文着眼于闭环环境下动态系统中的故障诊断问题.介绍了目前闭环系统故障诊断的研究意义, 特别关注了开闭环故障诊断的不同,并概述了现有的闭环系统故障诊断方法. 通过仿真实验比较了典型开环系统和闭环系统中故障诊断的不同性能.最后探讨了闭环系统故障诊断研究中 亟待解决的问题以及未来可能的研究方向.     

On computational stochastic structural dynamics applying finite elements

Summary This article presents a review of the state of the art of techniques on computational stochastic structural dynamics applying the finite elements. Linear systems under random excitations, quasi-linear systems, nonlinear systems excited by stochastic disturbances, and spatially stochastic nonlinear systems are included. For spatially stochastic linear and nonlinear systems under stochastic and deterministic excitations, alternative approaches, proposed by the author, to the so-called stochastic finite element method are introduced. The introduced approaches are free from the limitations of the: (a) normal mode analysis for linear and quasi-linear systems, (b) normal mode with statistical linearization for nonlinear systems, and (c) perturbation approximation techniques for spatially stochastic systems. The introduced approaches for nonlinear systems are applicable to systems undergoing large deformations of finite strains and finite rotations. Selected computed results are included to demonstrate their simplicity and efficiency.     

仿射非线性奇异系统的受控分布

研究非线性奇异系统的受控不变分布问题.讨论了非线性奇异系统的受控不变分布算法与该系统经过状态反馈转化为正常非线性系统的受控不变分布算法的关系.得到了在一定条件下,正则非线性奇异系统的受控不变分布算法与该系统经过状态反馈转化为正常非线性系统的受控不变分布算法的一致性.并给出一个例子说明本文的结果.     

A survey on Markovian jump systems: Modeling and design

Markovian jump systems are a special class of hybrid and stochastic systems which can be used to describe many real world applications, such as manufacturing systems, power systems, chemical systems, economic systems, communication and control, etc. In this paper, a survey on recent developments of modeling, analysis and design of Markovian jump systems is presented. First, stability issues on Markovian jump systems are addressed. Then a variety of control and filter design methods are systematically recalled. Furthermore, the new trends of Markovian jump systems with uncertain transition rates as well as semi-Markovian jump systems are also discussed.     

Crisis IT design implications for high risk systems: systems,control and information propositions

The systems view is presented as a complement to the more traditional scientific approach to help reduce and mitigate risk in high risk systems. Implications for this systemic approach are described, principally in the areas of control and information. Most generally, we investigate how high risk systems use information to maintain control, and how IT systems should be designed to support this activity. Two variations in the systems view – the objective and constructive – are distilled and compared, and for each, the implications for crisis IT systems design are discussed. The limitations of the two variations of the systems view are presented, as is a brief annotated bibliography for further reading about the systems view.     

Complexly Organised Dynamical Systems

Both natural and engineered systems are fundamentally dynamical in nature: their defining properties are causal, and their organisational and functional capacities are causally grounded. Among dynamical systems, an interesting and important sub-class are those that are autonomous, anticipative and adaptive (AAA). Living systems, intelligent systems, sophisticated robots and social systems belong to this class, and the use of these terms has recently spread rapidly through the scientific literature. Central to understanding these dynamical systems is their complicated organisation and their consequent capacities for re- and self-organisation. But there is at present no general analysis of these capacities or of the requisite organisation involved. We define what distinguishes AAA systems from other kinds of systems by characterising their central properties in a dynamically interpreted information theory.     

Linear periodically time-varying discrete-time systems: Aliasing and LTI approximations

Linear periodically time-varying (LPTV) systems are abundant in control and signal processing; examples include multirate sampled-data control systems and multirate filter-bank systems. In this paper, several ways are proposed to quantify aliasing effect in discrete-time LPTV systems; these are associated with optimal time-invariant approximations of LPTV systems using operator norms.     

广义信息系统及其决策规则

提出一类更广泛的信息系统,称其为广义信息系统．它包含了完备信息系统、不完备信息系统和多值信息系统．给出了广义信息系统集合近似的概念、方法和相关性质．讨论了广义信息决策系统的决策描述形式．这种决策描述形式易于转化为Skolem标准型，可以直接应用于人工智能的归结推理．     

On controllability,near-controllability,controllable subspaces,and nearly-controllable subspaces of a class of discrete-time multi-input bilinear systems

This paper considers a class of discrete-time multi-input inhomogeneous bilinear systems. The structure of such systems is most close to linear time-invariant systems’ but they own a strong property. That is, if the systems are uncontrollable, they can still be nearly controllable. Necessary and sufficient conditions for controllability and near-controllability of the systems are established by using a classical decomposition. Furthermore, a geometric characterization is given for the systems such that controllable subspaces and nearly-controllable subspaces are derived and characterized. Similar results on controllability are also obtained for the continuous-time counterparts of the systems. Finally, examples are provided to demonstrate the conceptions and results of this paper.     

Control of nonholonomic systems with extended base space dynamics

This paper extends certain results in Reference 1 to a more general class of nonholonomic systems with extended base space dynamics. This extension is important in applications for which control actuator dynamics are significant. These nonlinear control systems are referred to as nonholonomic control systems owing to certain nonintegrability assumptions which are made. The class of systems considered in this paper are characterized by general nonlinear base space dynamics that are input-output decouplable. Controllability results for this class of nonholonomic control systems are presented.     

Reachability analysis of complex planar hybrid systems

Hybrid systems are systems that exhibit both discrete and continuous behavior. Reachability, the question of whether a system in one state can reach some other state, is undecidable for hybrid systems in general. In this paper we are concerned with GSPDIs, 2-dimensional systems generalizing SPDIs (planar hybrid systems based on “simple polygonal differential inclusions”), for which reachability have been shown to be decidable. GSPDIs are useful to approximate 2-dimensional control systems, allowing the verification of safety properties of such systems.     

Modeling and Identification of Multirate Systems

Multirate systems are abundant in industry; for example, many soft-sensor design problems are related to modeling, parameter identification, or state estimation involving multirate systems. The study of multirate systems goes back to the early 1950s, and has become an active research area in systems and control. This paper briefly surveys the history of development in the area of multirate systems, and introduces some basic concepts and latest results on multirate systems, including a polynomial transformation technique and the lifting technique as tools for handling multirate systems, lifted state space models, parameter identification of dual-rate systems, how to determine fast single-rate models from dual-rate models and directly from dual-rate data, and a hierarchical identification method for general multirate systems. Finally, some further research topics for multirate systems are given.     

A Survey of Output Feedback Robust MPC for Linear Parameter Varying Systems

For constrained linear parameter varying (LPV) systems, this survey comprehensively reviews the literatures on output feedback robust model predictive control (OFRMPC) over the past two decades from the aspects on motivations, main contributions, and the related techniques. According to the types of state observer systems and scheduling parameters of LPV systems, different kinds of OFRMPC approaches are summarized and compared. The extensions of OFRMPC for LPV systems to other related uncertain systems are also investigated. The methods of dealing with system uncertainties and constraints in different kinds of OFRMPC optimizations are given. Key issues on OFRMPC optimizations for LPV systems are discussed. Furthermore, the future research directions on OFRMPC for LPV systems are suggested.      

线性时变广义系统的能控性与能观性问题

讨论了线性时变系统和线性时变广义系统的两个基本问题, 得到了两种判定时变系统能控性与能观性的必要条件, 该判定条件只依赖于系统矩阵A(t)和输入矩阵B(t), 不必计算系统的系统状态转移矩阵, 使得判别时变系统能控性与能观性易于实现. 说明了本文结论是线性定常系统相应结论的自然扩展. 对进一步深入研究时变系统和时变广义系统具有实际启发作用.     

Normal forms and the multiple-times expansion method for finite-dimensional integrable Hamiltonian systems

The authors apply the method of multiple-times expansion to finite-dimensional integrable Hamiltonian systems of polynomial type in order to determine integrable Hamiltonian systems and to derive new integrable systems from previously known ones. Recursion operators for the derived integrable systems are obtained. Normal forms for finite-dimensional integrable Hamiltonian systems are also constructed. It is demonstrated that the Hamiltonians found by the multiple-times expansion method are indeed the normal form expansions.     

分布参数切换系统的稳定性分析

将切换系统的概念引入到分布参数系统中，提出分布参数切换系统的概念．结合切换系统和分布参数系统的建模方法，建立了两类分布参数切换系统的模型．运用切换系统的稳定性分析方法，对两类分布参数切换系统的稳定性进行分析，得出了指数稳定的充分条件．仿真示例验证了定理的正确性．     

Dynamics and control of a class of underactuated mechanical systems

This paper presents a theoretical framework for the dynamics and control of underactuated mechanical systems, defined as systems with fewer inputs than degrees of freedom. Control system formulation of underactuated mechanical systems is addressed and a class of underactuated systems characterized by nonintegrable dynamics relations is identified. Controllability and stabilizability results are derived for this class of underactuated systems. Examples are included to illustrate the results; these examples are of underactuated mechanical systems that are not linearly controllable or smoothly stabilizable