EXACT CONTROLLABILITY OF A CLASS OF DISTRIBUTED PARAMETER SYSTEMS

The exact controllability of a class of distributed parameter systems governedby Petrowsky equations is considered.On the basis of the Hilbert Uniqueness Methodproposed by J.L.Lions,it is found that the Petrowsky systems with Dirichlet boundarycontrol are exactly controllable.     

Tracking control for air-breathing hypersonic cruise vehicle based on tangent linearization approach

This paper is focused on developing a tracking controller for a hypersonic cruise vehicle using tangent linearization approach. The design of flight control systems for air-breathing hypersonic vehicles is a highly challenging task due to the unique characteristics of the vehicle dynamics. Motivated by recent results on tangent linearization control, the tracking control problem for the hypersonic cruise vehicle is reduced to that of a feedback stabilizing controller design for a linear time-varying system which can be accomplished by a standard design method of frozen-time control. Through a proper model transformation, it can be proven that the tracking error of the designed closed-loop system decays exponentially. Simulation studies are conducted for trimmed cruise conditions of 110 000 ft and Mach 15 where the responses of the vehicle to step changes in altitude and velocity are evaluated. The effectiveness of the controller is demonstrated by simulation results.     

二能级开放量子系统相干保持的最优控制策略

二能级量子系统在开放环境下的相干保持是量子器件实用化的关键.针对二能级开放量子系统的相干保持问题,首先将系统的主方程模型转化为实向量空间上的状态空间模型.然后借助经典最优控制的思想,提出了一种既保证系统控制能量最小,同时又最大程度的减小消相干的最优控制策略.最后就一个典型的二能级开放量子系统仿真实现其相干保持,仿真结果显示了该方案的优越性.     

DENOISING AND HARMONIC DETECTION USING NONORTHOGONAL WAVELET PACKETS IN INDUSTRIAL APPLICATIONS

New industrial applications call for new methods and new ideas in signal analysis. Wavelet packets are new tools in industrial applications and they have just recently appeared in projects and patents. In training neural networks, for the sake of dimensionality and of ratio of time, compact information is needed. This paper deals with simultaneous noise suppression and signal compression of quasi-harmonic signals. A quasi-harmonic signal is a signal with one dominant harmonic and some more sub harmonics in superposition. Such signals often occur in rail vehicle systems, in which noisy signals are present. Typically, they are signals which come from rail overhead power lines and are generated by intermodulation phenomena and radio interferences. An important task is to monitor and recognize them. This paper proposes an algorithm to differentiate discrete signals from their noisy observations using a library of nonorthonormal bases. The algorithm combines the shrinkage technique and techniques in regression analysis using Shannon Entropy function and Cross Entropy function to select the best discernable bases. Cosine and sine wavelet bases in wavelet packets are used. The algorithm is totally general and can be used in many industrial applications. The effectiveness of the proposed method consists of using as few as possible samples of the measured signal and in the meantime highlighting the difference between the noise and the desired signal. The problem is a difficult one, but well posed. In fact, compression reduces the level of the measured noise and undesired signals but introduces the well known compression noise. The goal is to extract a coherent signal from the measured signal which will be “well represented” by suitable waveforms and a noisy signal or incoherent signal which cannot be “compressed well” by the waveforms. Recursive residual iterations with cosine and sine bases allow the extraction of elements of the required signal and the noise. The algorithm that has been developed is utilized as a filter to extract features for training neural networks. It is currently integrated in the inferential modelling platform of the unit for Advanced Control and Simulation Solutions within ABB’s industry division. An application using real measured data from an electrical railway line is presented to illustrate and analyze the effectiveness of the proposed method. Another industrial application in fault detection, in which coherent and incoherent signals are univocally visible, is also shown.     

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.     

基于FRFT的SNCK信号非相干解调

在采用相干解调方法进行接收时,正弦型非线性切普键控（sine non linear chirp keying, SNCK）信号受相位误差和多普勒频移影响较大,针对此问题提出一种将其近似为分段线性调频（linear frequency modulation, LFM）信号,采用分数阶傅里叶变换（fractional fourier transform, FRFT）进行解调的非相干解调方法。将FRFT解调方法与经典相干解调方法进行对比,通过理论推导和仿真分析发现,在严格同步条件下,SNCK信号相干解调性能优于FRFT解调方法,并且信号码元长度对FRFT解调性能有微弱的影响。但FRFT解调不受相位误差的影响,且具有相对较高的抗多普勒频移能力。     

非线性系统的模糊滑动模态控制

针对未建模的动态非线性系统,根据滑动模态控制原理,导出了基于Ｌｙａｐｕｎｏｖ稳定性的一种模糊控制器设计方法;避免了以往非线性滑模控制中控制信号的不连续造成系统“颤动”问题;显示出模糊推理的作用。     

Establishing formal state space models via quantization forquantum control systems

1.INTRODUCTION Quantumtheoryisoneofthemostimportantachieve mentsinthe20thcentury,anditdisclosesthestruc tures,characteristicsandmotionlawsofmatterinthe microcosmicfieldandleadsusfromthemacroscopical worldintomicrosystems.Aseriesofnewphenomena whicharedifferentfromclassicalsystemshavebeen discovered,suchasquantumentanglement,quantum coherenceanduncertainty.Meanwhile,quantum theoryandquantummethodsarealsowidelyusedin differentfieldssuchaschemicalreaction,geneticen gineering,atomicphysicsandi…     

Controllability and observability of networked control systems with time-varying delays

The controllability and observability of networked control systems are studied. Aiming at the networked control system with time-varying delay, the sufficient and necessary conditions for complete controllability and complete observability of the system are presented, respectively. Because of Markov characteristic of the network-induced delay, in terms of stochastic theory, a sufficient and necessary condition for completely mean value controllability of networked control systems is obtained. Further, the conditions that the controllability and observability of networked control systems are equivalent to the initial time-invariant system are given. Controllability and observability realization indexes are also discussed, respectively. The numerical example demonstrates the effectiveness of the proposed theory.     

基于非线性跟踪的混沌反控制

针对连续仿射非线性系统，提出一种基于非线性跟踪的混沌反控制统一方法。设计了非线性跟踪控制规律，使非线性非混沌系统跟踪混沌输入信号，从而使非混沌系统产生与混沌输入信号拓扑共轭的混沌现象。仿真结果表明，该方法能够在线性可控和相对阶大于3的仿射非线性系统中产生混沌现象。     

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…     

Design of control sequence of pulses for the population transfer of high dimensional spin 1/2 quantum systems

On the basis of the relationship between the Hamiltonian of spin 1/2 quantum system under control and the energy level structure and transitions, a radio frequency pulse sequence is designed using intuitive and half counter-intuitive sequences of pulse to transfer the population of the 3-qubit system coherently. The effectiveness of the designed control sequence is verified through the system simulation experiment of the evolution of state. In principle, the design method of the control pulse sequence proposed can be generalized to use in the quantum systems of higher dimension.     

基于模糊滑模的移动机械臂控制研究

针对移动机械臂的输出跟踪问题,采用PD 前馈控制结构,结合滑模控制和模糊控制的设计思想为其设计了模糊滑模控制器.滑模控制的优点是滑动模态对系统摄动、不确定性以及干扰的完全自适应性,但同时也带来了抖振,运用模糊切换的方法解决了滑动模态的抖振问题.仿真实验表明,所设计的控制器不仅很好地跟踪给定轨迹,而且能有效地削弱系统的抖振.     

Decentralized adaptive fuzzy control of time-delayed interconnected systems with unknown backlash-like hysteresis

The problem of decentralized adaptive fuzzy control for a class of time-delayed interconnected nonlinear systems with unknown backlash-like hystersis is discussed. On the basis of the principle of variable structure control （VSC） and by using the fuzzy systems with linear adjustable parameters that are used to approximate plant unknown functions, a novel decentralized adaptive fuzzy control strategy with a supervisory controller is developed. A general method, which is modeled the backlash-like hysteresis, is proposed and removes the assumption that the boundedness of disturbance, and the slope of the backlash-like hystersis are known constants. Furthermore, the interconnection term is supposed to be pth-order polynomial in time-delayed states. In addition, the plant dynamic uncertainty and modeling errors are adaptively compensated by adjusting the parameters and gains on-line for each subsystems. By theoretical analysis, it is shown that the closed-loop fuzzy control systems are globally stable, with tracking error converging to zero. Simulation results demonstrate the effectiveness of the approach.     

具有控制约束的不确定离散系统最优保性能控制

对一类具有范数有界时变参数不确定性和控制输入约束的离散时间线性系统,采用线性矩阵不等式处理方法,导出了保性能控制律存在的条件,证明了该条件等价于一组线性矩阵不等式的可行性问题,并用这组线性矩阵不等式的可行解给出了保性能控制律的一个参数化表示。进而,通过建立并求解一个凸优化问题,给出了具有控制约束的不确定离散系统最优保性能控制律设计方法。     

集成知识系统的权责控制

集成知识系统由各类知识系统主体组成, 用于整合企业不同研发部门产生的不同领域的知识. 在整合各领域知识过程中, 需要通过权责控制实现主体活动范围的界定与分析, 以维持主体自治与系统管制之间的平衡, 适应领域知识之间复杂多变的依赖关系. 为了满足这一需求, 提出了权责模型, 在假定主体进程与系统进程间存在共同约定的基础上, 构造了功用空间和上下文代数等结构, 又以此为基础构造了权责空间, 并完成了权责运算及权责关系等形式化工作. 权责模型为集成知识系统实现权责控制提供了一个可行而又有效的方案, 通过权责和权责关系可以完成描述主体活动、界定主体自律范围以及分析权责关系冲突等工作.     

神经网络控制、无模型控制PID控制仿真比较

在同一条件下，对三种仅用受控系统I／O数据来设计控制器的方法进行了控制性能仿真比较，三个受控系统分别取自文[1]和[5]。三种不同的控制方法各有其优缺点，仿真结果表明：无模型自适应控制具有其他两种方法所不具备的优点，适合处理结构时变、参数时变、阶教时变非线性离散时间系统的控制问题。     

一种自适应鲁棒跟踪模糊控制新算法

针对一类非线性不确定系统 ,在用T S模糊系统对未知聚拢不确定函数进行逼近的基础上 ,利用系统的耗散理论 ,系统地提出了一种自适应鲁棒跟踪模糊控制新算法。该算法基于一个新的Lyapunov函数 ,不仅可以使控制算法避免其它自适应控制算法中时常存在的奇异问题 ,而且还可以使自适应学习参数的数目减至最少 ,便于工程实现 ,并可确保闭环系统渐近稳定 ,系统的跟踪误差为零。经仿真研究表明 ,所提出的算法是有效的     

Controlling the probability density of quantum systems

A new method to design a quantum controller which directly controls the probability density function(PDF) of quantum systems is proposed.Based on the quantum model from the PDF perspective,two specific control algorithms are proposed with uniform and non-uniform fields,respectively.Then a detailed control algorithm with convergence analysis is given for the small error case.By appropriately estimating the selected Lyapunov function,more accurate control effect is achieved.The proposed scheme provides a constructive method to find appropriate parameters for controller design.     

一类非线性级联系统的鲁棒不变切换控制

研究了一类具有结构不确定性的单输入非线性级联系统的鲁棒不变切换控制问题。通过基于鲁棒严格无源技术和线性子系统状态反馈的切换控制来镇定线性子系统,同时保证了指定区域的正不变性,从而得到了该类系统鲁棒不变切换控制的充分条件。在适当的假设下,得到了系统的半全局渐近稳定。设计中无需ISS假设或非线性项的线性增长条件假设。在MATLAB环境下的仿真结果表明了设计的有效性。