非线性脉冲混合系统的指数ISS

利用输入－状态稳定性（ISS）李雅普诺夫函数法,研究了非线性脉冲混合系统无外部输入时的指数稳定性,导出了具有外部输入时系统满足ISS的充分条件,从而给出了非线性脉冲混合系统的指数ISS的判据,并通过数值仿真验证了判据的有效性。     

Stability of feedback systems with periodic parameters†

This paper deals with a frequency domain technique for stability analysis of linear feedback systems with periodically time-varying parameters. The approximate method of signal balance used by Clark et al. (1064) is generalized to yield better results in the case of a wide variety of systems including some TVP-coupled systems. For systems with TVP coupling, a novel and simple method of ‘pivotal points’ is suggested for quickly sketching the stability boundaries making use of the known stability of subsystems. The results of perturbation analysis (Rao 1969) are found to support the pivotal paint method.     

基于观测器的输出反馈电子节气门控制器设计

针对电子节气门系统的状态变量不完全可测量, 设计了一个基于观测器的输出反馈电子节气门控制系统. 该系统由一个估计不可测量状态的降阶观测器和一个非线性状态反馈控制器组成. 同时在控制器中引入了跟踪误差的积分项以抑制跟踪静差. 将建模误差和观测器误差等不确定性看作外部扰动, 在输入到状态稳定性(Input to state stability, ISS)理论框架下分析了跟踪误差系统的鲁棒性, 并据此给出了选择控制器参数的指导性原则.仿真及实验结果表明, 基于观测器的输出反馈控制器能够很好地实现电子节气门的跟踪控制.     

Guidance Laws With Input Constraints and Actuator Failures

A novel three‐dimensional fault‐tolerant control guidance law is proposed for interception of maneuvering targets in the presence of external disturbances, actuator failures, and control input constraints. The input‐to‐state stability (ISS) method is introduced to design the fault‐tolerant control guidance law to guarantee robust tracking of a maneuvering target. Then, a saturated fault‐tolerant control guidance law is constructed using a modified saturation function to ensure the resulting control signal will never incur input constraints, and the convergence to a small neighborhood of origin is ensured in theory. Simulation results show that the presented approach is effective in achieving a successful interception against target maneuvers, external disturbances, actuator failures, and control input constraints.     

具有状态和控制约束的受扰离散线性切换系统的反馈控制

本文的主要贡献是针对一类具有重置函数及由外部不能控事件决定动态的离散时间线性切换系统,给出一些稳定性综合结论. 当系统受到外部有界扰动, 及状态和控制量约束时, 在输入到状态稳定性理论框架下, 研究使得系统镇定的线性状态反馈控制器设计方法. 针对这类混杂系统, 本文引入了受控D不变性的概念, 并给出检测某一混杂区域具有受控D不变性的充要条件. 进而, 提出一种能够使得受扰的线性切换系统镇定, 同时保证状态和控制量满足其约束的反馈矩阵的计算方法. 最后, 通过一个由两个子系统构成的数值例子来说明本文技术的应用性.     

Input‐to‐state‐stability‐type comparison principles and input‐to‐state stability for discrete‐time dynamical networks with time delays

This paper investigates the input‐to‐state stability (ISS) issue for discrete‐time dynamical networks (DDNs) with time delays. Firstly, a general comparison principle for solutions of DDNs is proposed. Then, based on this general comparison principle, three kinds of ISS‐type comparison principles for DDNs are established, including the comparison principle for input‐to‐state ‐stability, ISS, and exponential ISS. The ISS‐type comparison principles are then used to investigate stability properties related to ISS for three kinds (linear, affine, and nonlinear) of DDNs. It shows that the ISS property of a DDN can be derived by comparing it with a linear or lower‐dimension DDN with known ISS property. By using methods such as variation of parameters, uniform M‐matrix, and the ISS‐type comparison principle, conditions of global exponential ISS for time‐varying linear DDNs with time delays are derived. Moreover, the obtained ISS results for DDNs are extended to the hybrid DDNs with time delays. As one application, the synchronization within an error bound in the sense of ISS is achieved for DDNs with coupling time delays and external disturbances. Finally, two examples are given to illustrate the results. Copyright © 2011 John Wiley & Sons, Ltd.     

MAN ETs中基于TCP的网络拥塞识别控制算法

针对现有TCP协议无法区分MANETs网络性能下降原因的问题,分析移动自组织网络的网络拥塞、MAC层及路由中断等现象出现的可能原因,提出基于短期网络吞吐量（short time throughput ,STT）的拥塞识别策略,改进基于带宽估计的慢启动改进算法（improved slow start ,ISS）,在此基础上提出一种适用于移动Ad Hoc网络的拥塞识别控制算法TCP‐AHN （TCP for Ad Hoc networks）。仿真结果表明, TCP‐AHN算法在平均窗口拥塞值、网络吞吐量及分组平均重传次数方面优于传统拥塞控制算法,验证了TCP‐AHN算法的有效性。     

入侵检测技术

入侵检测（Intrusion Detection）,顾名思义,即是对入侵行为的发觉。它在计算机网络或计算机系统中的若干关键点收集信息,通过对这些信息的分析来发现网络或系统中是否有违反安全策略的行为和被攻击的迹象。进行入侵检测的软件与硬件的组合便是入侵检测系（Intrusion Detection System,简称IDS）。与其他安全产品不同的是,入侵检测系统需要更多的智能,它必须能将得到的数据进行分析,并得出有用的结果。     

入侵检测技术

入侵检测(Intrusion Detection),顾名思义,即是对入侵行为的发觉。它在计算机网络或计算机系统中的若干关键点收集信息,通过对这些信息的分析来发现网络或系统中是否有违反安全策略的行为和被攻击的迹象。进行入侵检测的软件与硬件的组合便是入侵检测系统(Intrusion Detection System,简称IDS)。与其他安全产品不同的是,入侵检测系统需要更多的智能,它必须能将得到的数据进行分析,并得出有用的结果。     

Input-to-State Stabilization of Nonlinear Impulsive Delayed Systems: An Observer-Based Control Approach

This paper addresses the problems of input-to-state stabilization and integral input-to-state stabilization for a class of nonlinear impulsive delayed systems subject to exogenous dis- turbances. Since the information of plant’s states, time delays, and exogenous disturbances is often hard to be obtained, the key design challenge, which we resolve, is the construction of a state observer-based controller. For this purpose, we firstly propose a corresponding observer which is independent of time delays and exogenous disturbances to reconstruct (or estimate) the plant’s states. And then based on the observations, we establish an observer-based control design for the plant to achieve the input-to-state stability (ISS) and integral-ISS (iISS) properties. With the help of the comparison principle and average impulse interval approach, some sufficient conditions are presented, and moreover, two different linear matrix inequalities (LMIs) based criteria are proposed to design the gain matrices. Finally, two numerical examples and their simulations are given to show the effectiveness of our theoretical results.