光反馈激光器非线性仿真研究

一些传统计算方法对非线性系统的分析存在着一些困难。针对光反馈半导体激光器收发系统微分方程组的特点,对非线性性质做出了数学上的分析,考虑到在光反馈半导体激光器收发系统中,其微分方程含有延迟因子,无法直接利用多节点上的值的加权和来近似计算斜率。基于龙格-库塔法提出了一种有效的数值仿真算法,并在matlab平台上对给定参数条件下的发射端与接收端的归一化光场以及同步误差进行了仿真,证明了接收端光场信号可以很快与发射端光场信号一致,仿真结果表明仿真算法能有效对系统进行仿真分析。     

Observer design for systems with multivariable monotone nonlinearities

Globally convergent observers are designed for a class of systems with multivariable nonlinearities. The approach is to represent the observer error system as the feedback interconnection of a linear system and a state-dependent multivariable nonlinearity. We first extend an earlier design (Automatica 37 (12) (2001) 1923) to multivariable nonlinearities, satisfying an analog of the scalar nondecreasing property. Next, we exploit the structure of the nonlinearity to relax the positive real restriction on the linear part of the observer error system. This relaxed design renders the feasibility conditions less restrictive, and widens the applicability of the observer, as illustrated with examples. Finally, output nonlinearities are studied and the design is extended to be adaptive in the presence of unknown parameters.     

A Multiobjective Optimization Model for Dynamic Reconfiguration of Ring Topologies with Stochastic Load

In this paper we describe a heuristic procedure to generate solutions to a multiobjective stochastic, optimization problem for a dynamic telecommunications network. Generating Pareto optimal solutions can be difficult since the optimization problem is computationally challenging and moreover the network must be reconfigured in near real time, for example, to recover connectivity after a severe weather event. There are two main contributions of this paper. First, we show mathematically how a certain deterministic equivalent optimization problem can be solved instead of the stochastic one, thus facilitating computations. Second, we test our heuristic under a wide set of simulated conditions (e.g., atmospheric obscuration due to differing levels of cloud cover, different demand patterns) and show that it achieves near Pareto optimality in a short amount of time.     

All stability multipliers for repeated MIMO nonlinearities

For block structured monotone or incrementally positive n-dimensional nonlinearities, the largest class of convolution operators (stability multipliers) that preserve positivity is derived. These multipliers can be used in conjunction with positivity and IQC stability criteria to evaluate stability and robustness of MIMO feedback systems.     

增益衰减对预失真算法的性能优化

在放大器功率增益对预失真线性化性能的影响问题的研究中,线性化技术需要更大的线性工作区域和更高的线性化性能.为提高变压器的性能,提出一种新的预失真算法优化方法,调整预失真器的应用模式,通过衰减输出功率增益扩展线性工作区域,并能实现较好的线性化性能.实验验证了上述优化方法的有效性.合理选择实际输出功率增益,利用增益衰减优化预失真算法,可以增大预失真放大器的线性工作区域,提升变压器的线性化性能.改进的优化方法为预失真技术的研究和应用提供了科学依据.     

Robust nonlinear predictor for dead-time systems with input nonlinearities

Since the seminal work of Smith, predictor structures have been used to control processes with dead-time. Predictors allow the control of this type of process with a delay-free nominal model, which simplifies the control design. In this paper, a nonlinear filtered Smith predictor (NLFSP) structure is proposed for systems with input nonlinearities. It is shown that the NLFSP maintains the characteristics of the linear filtered Smith predictor and that with appropriate tuning, it can increase the robustness of the closed-loop system or improve the disturbance rejection response. The NLFSP is applied to a simulated CSTR process to demonstrate these characteristics.     

功放非线性特性及预失真模型研究

针对功率放大器的非线性特性问题进行研究,分别根据无记忆和有记忆两种类型的功放特性曲线用最小二乘法拟合出功放模型,根据线性化原则以及输出幅度限制和功率最大化约束,建立预失真模型.以误差函数和工程可实现性为评价指标,从不同模型中分别选出无记忆和有记忆最优模型.仿真测试表明被选取的多项式预失真模型能够有效的改善功率放大器的非线性具有较好的抗噪性,对工程实践中预失真器的设计具有一定的指导意义.     

安全能量效率优化的传感器网络传输研究

研究了射频无线充能传感器网络通信系统的安全传输及能量效率问题,针对传感器网络能量受限而无线通信容易被窃听的问题,利用物理层安全技术,提出了一种两阶段的安全传输协议。通过联合优化发送功率、射频能量协方差矩阵、敏感信息波束成型以及协作干扰协方差矩阵,使得传感器网络的安全能量效率达到最大。针对所提出的非凸问题,利用Dinkelbach方法将包含分式形式的目标函数简化,利用连续参数凸近似方法将非凸问题转化为可解形式,进而使用收敛迭代算法得到原问题的近似最优解。仿真结果表明,与对比方案相比,提出的传输方案可以在保证安全通信的基础上有效提高安全能量效率。     

能力风暴智能机器人无线通信系统的研究

提出了实现能力风暴智能机器人之间无线通信的一种方法,介绍了能力风暴智能机器人平台及无线收发模块的功能,分析了用无线收发模块实现机器人之间无线通信的原理和设计要点.该无线通信系统脱离了计算机的控制,机器人可自行收发数据,实验结果表明:在有效范围内机器人之间能进行快速有效的通信.     

无线光通信调制方式性能分析

无线光通信有多种调制方式,但缺少综合的分析.误码率(BER)是衡量无线光通信系统不同调制方式优劣的重要性能指标,如何正确统计误码性能显得尤为重要.介绍了无线光通信系统以及不同调制方式的基本原理,利用计算机仿真软件,研究在理想信道下实现无线光通信系统误码性能分析的方法,在对四种典型的无线光通信调制方式一OOK、PPM、DPPM和DPIM调制方式的符号结构分析的基础上,分析比较了上述四种调制方式的功率利用率、带宽利用率、传输容量以及抗码间干扰等性能.理论分析及仿真结果表明:DPPM和DPIM调制方式更加适合于未来无线光通信系统.为无线光通信调制方式的选取提供一定的参考依据,并指出其发展趋势.     

Gain scheduled controllers for dynamic systems using sector nonlinearities

In this work we explore the use of gain scheduling for the control of nonlinear systems. The nonlinear system is represented locally by uncertain linear models using sector nonlinearities representation. The uncertain linear models are then used to design a family of robust controllers. We propose a gain scheduling procedure for the problem of guaranteed transition from an actual operating condition to a desired one by constructing a pre-specified path in the state space for the system operating points. As far as we know this problem has not been addressed before. The gain scheduling control procedure given is illustrated in the context of the regulator problem with state feedback.     

Observer design for discrete-time systems subject to time-delay nonlinearities

In this paper, we address the problem of designing nonlinear observers for dynamical discrete-time systems with both constant and time-varying delay nonlinearities. The nonlinear system is assumed to verify the usual Lipschitz condition that permits us to transform the nonlinear system into a linear time-delay system with structured uncertainties. The existence of the observer-gain is ensured by the solution of a one linear matrix inequality. An illustrative example is included to demonstrate the advantage of the proposed observation technique.     

Application of quadratic differential forms to designing linear controllers for nonlinearities

We consider the following problem: given a nonlinear system (possibly with memory), parametrize a class of linear systems that can be interconnected (through fairly general interconnection constraints) with the nonlinear system to yield a stable autonomous system. We address this problem in a behavioral theoretic setting by constructing Quadratic Differential Forms (QDFs) called storage functions associated with the linear system. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

某电子装备的机内测试系统设计

为了提高某航空电子装备的测试速度和测试的可靠性,设计了一种针对该电子装备的机内测试（BIT）系统。在系统中采用了上位机和下位机的多控制器形式,提出了基于无线通讯的数据传递方法,提出了机内测试与分布式测试的结合。该系统提高了电子装备的测试水平和测试诊断速度．也可用于大型工厂的生产监测。     

基于Internet网络的视频传输失真分析

基于Internet网络的视频通信必须进行差错控制,而差错控制需要准确估计视频流在Internet网络传输中产生的信道失真。对基于Internet网络的视频传输过程进行了失真分析,结合帧间差错扩散的特点和差错帧之间的相关性,提出一种估计包损失失真的通用模型,通过接收端提供的丢包反馈信息,可以准确估计传输中引入的失真。使用JVT/H.264编码的标准视频测试序列进行验证,该模型对信道失真的估计精度比在此之前所提出的其它模型有明显提高。     

Observers for systems with nonlinearities satisfying incremental quadratic constraints

We consider the problem of designing observers to asymptotically estimate the state of a system whose nonlinear time-varying terms satisfy an incremental quadratic inequality that is parameterized by a set of multiplier matrices. Observer design is reduced to solving linear matrix inequalities for the observer gain matrices. The proposed observers guarantee exponential convergence of the state estimation error to zero. In addition to considering a larger class of nonlinearities than previously considered, this paper unifies earlier related results in the literature. The results are illustrated by application to several examples.     

Optimal compensation of nonlinearities in the presence of noise

The problem of feedback linearization for control systems containing sign-type (jump) nonlinearities is considered. Sometimes it is theoretically possible to cancel such nonlinearities by feedback. But, even in that case, such cancellation involves the use of discontinuous feedback laws, which can behave poorly in the presence of noise. We formulate and solve a problem that allows us to obtain optimal feedback compensation of nonlinearities, assuming additive noise in the measurements. Some simple examples are included to illustrate the advantages of our approach.     

无线激光通信的发展前景探讨

文章根据无线激光通信和无线射频通信各自的工作频率（工作波长）特点,对比分析了由于工作频率（工作波长）的量变引起的性能的质变及无线激光通信在应用领域的优势和劣势,最后探讨了无线激光通信的应用领域,并根据其在国内外的技术现状,提出了无线激光通信在某些应用领域的改进方案。