Impulse observability and impulse controllability of regular degenerate evolution systems

Impulse observability and impulse controllability of regular degenerate evolution systems are discussed by using functional analysis and operator theory in Banach space. Necessary and sufficient conditions for the impulse observability and impulse controllability of the system are obtained. This research is theoretically important for studying the design of the degenerate evolution system.     

Recent progress on controllability/observability for systems governed by partial differential equations

<正> The main purpose of this paper is to overview some recent methods and results on controllability/observability problems for systems governed by partial differential equations.First,the authorsreview the theory for linear partial differential equations,including the iteration method for the nullcontrollability of the time-invariant heat equation and the Rellich-type multiplier method for the exactcontrollability of the time-invariant wave equation,and especially a unified controllability/observabilitytheory for parabolic and hyperbolic equations based on a global Carleman estimate.Then,the authorspresent sharp global controllability results for both semi-linear parabolic and hyperbolic equations,based on linearization approach,sharp observability estimates for the corresponding linearized systemsand the fixed point argument.Finally,the authors survey the local null controllability resultfor a class of quasilinear parabolic equations based on the global Carleman estimate,and the localexact controllability result for general hyperbolic equations based on a new unbounded perturbationtechnique.     

Uniform decay rate for the transmission wave equations with variable coefficients

This paper considers the stabilization of the transmission problem of wave equations with variable coefficients. By introducing both boundary feedback control and distribute feedback control near the transmission boundary, the author establishes the uniform energy decay rate for the problem.     

Reachability/controllability of high order mix-valued logical networks

This paper addresses the reachability/controllability of high order mix-valued logical control networks by using the semi-tensor product method, and presents some necessary and sufficient conditions for the reachability/controllability. The high order mix-valued logical network is converted into an algebraic form first, based on which the reachability/controllability of the system is then investigated, and several necessary and sufficient conditions are established. The study of several illustrative examples shows that our new method is very effective in dealing with the reachability/controllability of high order mix-valued logical control networks.     

Polarization characteristics and controllability mechanism of passive scattering elements

Polarization feature is one of the important features of radar targets, which has been used in many fields. In this paper,the grid models of some typical foreign moving targets are constructed on the simulation platform, such as glider, cruiser, fixed wing aircraft, and rotorcraft. The electromagnetic scattering characteristics of the moving platforms under the incidence of circular polarization waves are calculated. The typical polarization characteristics which the orthogonal and in-phase comp...     

High accuracy analysis of the finite element method for nonlinear viscoelastic wave equations with nonlinear boundary conditions

The standard finite elements of degree p over the rectangular meshes are applied to solve a kind of nonlinear viscoelastic wave equations with nonlinear boundary conditions, and the superclose property of the continuous Galerkin approximation is derived without using the nonclassical elliptic projection of the exact solution of the model problem. The global superconvergence of one order higher than the traditional error estimate is also obtained through the postprocessing technique.     

Asymptotic controllability of a class of discrete-time systems with disturbances

This article deals with the uniformly globally asymptotic controllability of discrete nonlinear systems with disturbances. It is shown that the system is uniformly globally asymptotic controllability with respect to a closed set if and only if there exists a smooth control Lyapunov function. Further, it is obtained that the control Lyapunov function may be used to construct a feedback law to stabilize the closed-loop system. In addition, it is proved that for periodic discrete systems, the resulted control Lyapunov functions are also time periodic.     

线性时变周期系统的能控性与能稳定性问题

线性时变周期系统是一类普遍存在的重要而又研究较少的系统。介绍了线性时变周期系统的几种应用实例,给出了两种判定时变周期系统能控性与能观性的必要条件,该判别条件的优点是不必计算系统的状态转移矩阵,使判别时变周期系统能控性与能观性简单、高效、易于实现。讨论了时变周期系统在状态反馈下的能稳定性问题,得到了类似于线性定常系统能控性与能稳定性关系的时变周期系统相应结论。说明了结论是线性定常系统相应结论的自然拓展。给出了数值算例的MATLAB仿真求解过程。仿真结果验证了结论的有效性。     

Leader selection for strong structural controllability of single-integrator multi-agent systems

This paper addresses the leader selection problem for strong structural controllability (SSC) of multi-agent systems (MASs). For a path-bud graph, it is proved that only one leader is required to guarantee the SSC of MASs. For a special type of topologies, based on the partition of the topology into disjoint pathes and path-buds, it is proved that the MASs is strongly structurally controllable if the root nodes of the pathes are selected as leaders. For general topologies, an algorithm is provided to determine the agents that can behave as leaders. For some special topologies, the minimum number of leaders guaranteeing the robust strong structural controllability (RSSC) of MASs is also obtained. Two examples are given to verify the effectiveness of the results.     

零模型及其在复杂网络研究中的应用

从假设检验这一源头出发,描述零模型方法产生的理论和实践背景,在生态学零模型启发中总结零模型的本质作用,并重点叙述在复杂网络拓扑结构研究中零模型的构建及其应用研究所取得的成果,讨论了复杂网络零模型研究的发展方向。     

Research on controllability for a class of fractional-orderlinear control systems

1.INTRODUCTION Therealobjectsaregenerallyfractional[1],however,thecontrolsystemsusedsofarareallconsideredas integer ordersystems.Thereasonisthecomplexity andtheabsenceofadequatemathematicaltoolsfor fractional ordersystems.Fractionalcalculusisanatu ralextensionoftheclassicalmathematics.Thefrac tionalcalculustheorywasdevelopedbyalotofmath ematicians[2,3]andtheapplicationdomainsoffrac tionalcalculushaveincreasedsignificantly.Lasttwo decadestheknowledgewasappliedincontroltheory,whichconcerned…     

二维广义系统Roesser模型局部能达和局部能控性

研究了二维广义系统Roesser模型的性质,推导出了该系统的状态响应公式.给出了其在矩形区域上局部能达和局部能控的充分必要条件.同时,利用二维Z变换理论,给出了二维广义系统Roesser模型局部能达和局部能控的等价定义,并得出该模型相应的局部能达和局部能控的新的充分必要条件.     

考虑惯性积时多旋翼的可控性分析与度量方法

旋翼飞行器每个旋翼只能提供单一方向的力,其可控性分析与度量问题有其特殊性。在已有研究的基础上,研究了多旋翼飞行器在惯性积不可忽略时的可控性分析方法。进一步地,提出了一种新的多旋翼飞行器可控性度量指标。与文献中已有指标相比,本文所提的指标不仅具有已有指标的功能,而且还能够反应飞行器惯性积的改变对其可控度的影响。最后,仿真结果表明了所给出的可控性分析方法以及可控性度量指标的有效性。     

Perturbation and robust controllability of singular distributed parameter control systems in Hilbert space

Perturbation and robust controllability of the singular distributed parameter control system are discussed via functional analysis and the theory of GE-semigroup in Hilbert space.The perturbation principle of GE-semigroup and the sufficient condition concerning the robust controllability of the singular distributed parameter control system are obtained,in which the controllability for singular distributed parameter control system is not destroyed,if we perturb the equation by small bounded linear operator.     

具有单框架控制力矩陀螺航天器的建模及可控性分析

针对具有单框架控制力矩陀螺的航天器姿态控制问题,将航天器与控制力矩陀螺看作整体系统,应用Lagrangian方程与Hamiltonian方程建立系统在重力场中的数学模型。在考虑航天器短时间内大角度机动前提下,将系统在Lagrangian形式下的状态方程简化成仿射非线性形式,以控制力矩陀螺框架角速度为输入变量,回避控制力矩陀螺在奇异情况下对系统的影响。随后应用系统Hamiltonian形式的保体积性与非线性系统可控性定理证明该系统可控,且系统可控性不受单框架控制力矩陀螺群个数、构型、奇异问题的影响。系统在重力场中的数学模型与可控性结论为以后进一步研究航天器姿态控制方法,航天器系统稳定性问题提供了理论依据。     

机载海洋波谱仪的浅海波浪参数反演

基于机载海洋波谱仪挂飞试验获得的实测数据,研究了波谱仪的信号处理和波浪参数反演算法。首先,采用海浪谱反演算法对挂飞试验获得的波谱仪数据进行处理,成功得到了海洋波浪方向谱,并反演出了波浪相关参数;然后,利用浅海波浪模型Kadomtsev-Petviashivilli(KP)方程模拟了该海域的波浪传播,研究该海域波浪的传播特性。将波谱仪测量结果与模拟结果进行对比,结果基本一致,证明了波谱仪信号处理和波浪参数反演算法的有效性,同时也验证了波谱仪能较精确地测量海浪,为星载海洋波谱仪的研制奠定了良好的基础。     

修复后性能下降的可修件的备件可用概率仿真算法

采用事件调度法的策略对装备使用与维修过程进行仿真,给出了修复后性能下降的可修件在先换新件和先换旧件两种策略下备件可用概率的仿真算法。该算法能精确计算安装在不同装备上、具有不同故障间隔时间分布、不同修复时间分布、可修次数受限的可修复部件的备件可用概率。仿真算例验证了算法的正确性。     

局域波分解算法

局域波分析是一种新的时频分析方法,该方法的关键是局域波分解算法,它的好坏直接影响到基本模式分量的精度,进而影响到它的实际应用。综述了各种局域波分解算法,讨论了各种算法的性能和特点,指出了改善局域波分解性能的具体措施和应用局域波分解算法应注意的有关问题,展望了局域波分解算法的可能发展。对局域波分解算法的改进和局域波分析的应用具有参考价值。     

毫米波探测器的超宽带耦合特性

探测器是近程探测系统的目标敏感装置, 容易受到电磁脉冲干扰。针对某型毫米波探测器超宽带(ultra-wideband, UWB)电磁脉冲抗扰度不清的实际情况, 围绕UWB辐照环境展开该型探测器的电磁脉冲耦合特性研究。将时域有限积分算法(finite integration technology, FIT)应用于探测器腔体耦合特性研究, 并结合UWB试验系统对探测器开展了辐照试验, 验证了FIT算法的有效性。仿真和试验结果表明, 探测器在竖直状态下的腔体屏蔽效能最差, 仿真试验中其屏蔽效能为20.40 dB; 试验得出探测器的效应场强阈值约为150 kV/m, 在辐照下会出现死机、虚警和硬损伤3种现象, 其中死机现象可通过电源复位恢复, 虚警和硬损伤为不可逆效应现象。