Hybrid Feedback Control and Robust Stabilization of Nonlinear Systems

In this paper, we show, for any nonlinear system that is asymptotically controllable to a compact set, that a logic-based, hybrid feedback can achieve asymptotic stabilization that is robust to small measurement noise, actuator error, and external disturbance. The construction of such a feedback hinges upon recasting a stabilizing patchy feedback in a hybrid framework by making it dynamic with a discrete state, while insisting on semicontinuity and closedness properties of the hybrid feedback and of the resulting closed-loop hybrid system. The robustness of stability is then shown as a generic property of hybrid systems having the said regularity properties. Auxiliary results give uniformity of convergence and of overshoots for hybrid systems, and give a characterization of asymptotic stability of compact sets.     

加权有限自动机在灰度图像中的应用

将WFA(加权有限自动机)作为灰度图像的描述工具,概括了如何从输入的图像计算相应的WFA(编码)以及如何从WFA出发画出其所定义的图像(解码).编码算法的新颖之处在于它从数学角度出发,利用的原理是状态图像的子块图像可以被自动机中状态的线性组合来表示.基于线性代数的算法更加高效简洁.     

Synthesis of Stabilization Systems with Unilateral Control Constraints

Automation and Remote Control - In practical applications of automatic control theory, one often deals with situations where the controls must range in some domain, in particular, take only...     

不确定控制系统的输出反馈镇定

本文研究具有匹配和非匹配不确定性系统的输出反馈镇定。在对不确定性的增长性作适当限制的条件下，利用本文引入输出反馈严格正实系统的概念，构造了保证团环系统在开球Ｂ上或在Ｒ＾ｎ上指数式稳定的光滑或解析输出反馈控制律。     

Inferring Finite Automata with Stochastic Output Functions and an Application to Map Learning

It is often useful for a robot to construct a spatial representation of its environment from experiments and observations, in other words, to learn a map of its environment by exploration. In addition, robots, like people, make occasional errors in perceiving the spatial features of their environments. We formulate map learning as the problem of inferring from noisy observations the structure of a reduced deterministic finite automaton. We assume that the automaton to be learned has a distinguishing sequence. Observation noise is modeled by treating the observed output at each state as a random variable, where each visit to the state is an independent trial and the correct output is observed with probability exceeding 1/2. We assume no errors in the state transition function.Using this framework, we provide an exploration algorithm to learn the correct structure of such an automaton with probability 1 – , given as inputs , an upper bound m on the number of states, a distinguishing sequence s, and a lower bound > 1/2 on the probability of observing the correct output at any state. The running time and the number of basic actions executed by the learning algorithm are bounded by a polynomial in ^–l, m, |s|, and (1/2-)^–1.We discuss the assumption that a distinguishing sequence is given, and present a method of using a weaker assumption. We also present and discuss simulation results for the algorithm learning several automata derived from office environments.     

基于Mealy机的汉字输入有穷自动机及其应用

从自动机理论的角度对汉字输入模型的建立进行了一定的研究,并相应地建立了一个基于Mealy有穷自动机的汉字输入有穷自动机模型,在这种模型中对自动机的输入进行了刻画,同时也对自动机的输出进行了相应地刻画,较之以前的汉字输入模型更全面。根据这种模型的特点还介绍了它在汉字GB码与BIG5码转换中的应用。     

短时滞网络控制系统鲁棒稳定性分析

本文主要研究了网络控制系统时延小于一个采样周期的稳定性,以及系统在扰动下控制器设计的问题,利用线性矩阵不等式方法得出离散时滞网络控制系统Lyapunov稳定性判据,同时给出了具有不确定性系统的鲁棒控制器。     

混合控制系统建模

混合控制系统起源于制造中连续流程的计算机辅助控制、广域通信网络、交通控制以及工业过程控制。     

Stabilization of the Networked Hybrid Systems with Communication Constraints and Its Applications

International Journal of Control, Automation and Systems - In this paper, a stabilization problem is investigated for a class of networked control systems with some communication constraints. A...     

基于能量的受迫哈密顿系统的镇定及在电力系统中的应用

有两个目的,第一目的是考虑电力系统的励磁镇定。将该系统表示为具有耗散的受迫哈密顿系统的形式,随后基于能量构造了李雅普诺夫函数来考察受迫系统的稳定性。第二个目的是提出广义哈密顿系统的模型,广义哈密顿系统具有外部能量供给、内部能量供给及能量消耗,状态空间被描述成具有二次张量场的流形,得到了广义哈密顿系统与坐标无关的全局模型。     

Parametric Stabilization of Quantized Interconnected Systems with Application to Coupled Inverted Pendulums

This paper studies the analysis of parametric stability and decentralized state feedback control of a kind of quantized interconnected systems. The output of each controller is quantized logarithmically before it is input to the subsystem, and the quantized density would affect the stability of the systems. First, a decentralized state feedback controller is designed for interconnected systems without quantization and the corresponding stable region is obtained. Second, for a given controller, the lower bound of the quantization density is evaluated from parameters of local controllers. Finally, the proposed method is applied to coupled inverted pendulums systems which can be viewed as quantized interconnected systems. The simulation results show that by using the proposed quantized controllers, the interconnected inverted pendulum systems are parametrically stabilized.     

基于脉冲切换控制的网络控制系统的镇定性

在网络控制系统的优化中,研究了离散时间域内带随机时延的网络控制系统的镇定性优化问题.首先将随机时延建模为一个马尔可夫链,然后在网络控制系统中引入模态依赖的脉冲切换控制器,建立了采用脉冲切换控制的网络控制系统模型.利用系统模型随机稳定性理论推导,得到使网络控制系统稳定的充分必要条件,并用迭代线性矩阵不等式方法求解了控制器,最后利用小车倒立摆做被控对象进行了数值仿真,仿真结果说明了控制方法的有效性.     

Stabilization of Sampled-Data Control Systems With Control Inputs Missing

This note is concerned with the stabilization problem for sampled-data control systems with control inputs missing. A sufficient condition is derived for the existence of exponentially stabilizing state feedback controllers via the switched system approach. The obtained condition establishes several quantitative relations among some system parameters (such as the sampling period and the exponential decay rate), the actual data missing rate, and the admissible data missing rate bound. Two illustrative examples are given to show the effectiveness of the proposed results.      

Prescribed-time Stabilization for a Class of Nonlinear Systems with Control Singularities

International Journal of Control, Automation and Systems - This paper studies the prescribed-time stabilization of a class of nonlinear systems with control singularities. The settling time is...     

Robust Stabilization of Uncertain Networked Control Systems with Data Packet Dropouts

The data packet dropouts phenomenon is usually inevitable when information transmit- ted among communication networks.In this paper,the robust stabilization problem for uncertain networked control systems with data packet dropouts is studied.First,an uncertain discrete-time switching system model is presented to describe these networked control systems.The stability equiv- alence is then proved between this switching system and an uncertain impulsive difference system. Moreover,a sufficient condition is obtained for the asymptotical stability of the nonlinear impulsive difference system.From this condition the robust stabilization problem is dealt with for the uncertain impulsive system.Main results are given in linear matrix inequalities.Finally a numerical example is given to illustrate the theoretical results.     

Compositional Abstractions of Hybrid Control Systems

Abstraction is a natural way to hierarchically decompose the analysis and design of hybrid systems. Given a hybrid control system and some desired properties, one extracts an abstracted system while preserving the properties of interest. Abstractions of purely discrete systems is a mature area, whereas abstractions of continuous systems is a recent activity. In this paper we present a framework for abstraction that applies to discrete, continuous, and hybrid systems. We introduce a composition operator that allows to build complex hybrid systems from simpler ones and show compatibility between abstractions and this compositional operator. Besides unifying the existing methodologies we also propose constructions to obtain abstractions of hybrid control systems.     

Stabilization of Discrete Time-Varying Systems by Output Control

Stabilization of a discrete linear time-varying system with uniformly bounded parameters and one output by output control is studied by synthesizing an asymptotically stable observer with a given observation error attenuation rate and solving the problem of stabilization by state control through special similarity transformations.     

Unstable Oscillating Systems with Hysteresis: Problems of Stabilization and Control

Journal of Computer and Systems Sciences International - The work is devoted to studying the dynamics of unstable oscillating systems (in the form of an inverted pendulum) controlled by the action...     

Controllability for Discrete Systems with a Finite Control Set

In this paper we consider the problem of controllability for a discrete linear control system x _k+1=Ax _k+Bu _k, u _k∈U, where (A,B) is controllable and U is a finite set. We prove the existence of a finite set U ensuring density for the reachable set from the origin under the necessary assumptions that the pair (A,B) is controllable and A has eigenvalues with modulus greater than or equal to 1. In the case of A only invertible we obtain density on compact sets. We also provide uniformity results with respect to the matrix A and the initial condition. In the one-dimensional case the matrix A reduces to a scalar λ and for λ>1 the reachable set R(0,U) from the origin is?