Adaptive robust control of nonholonomic systems with stochastic disturbances

Based on the Brockett’s necessary condition for feedback asymptotic stabilization[1], nonholonomic systems fail to be stabilized at the origin by any static continuous state feedback though they are open loop controllable. There are two novel approaches …     

卷绕传输系统偏心张力干扰的自适应消除法

提出一种自适应算法可用于补偿工业卷绕传输系统中因卷绕轴轮的偏心所造成的影响.轴轮的偏心导致卷绕物张力干扰,干扰信号的频率随轴轮转速而缓慢变化.提出的自适应算法基于锁相回路结构,可在线估测出干扰信号的相位及幅值大小并消除其影响.还给出了这种算法的频域分析及参数设计方法,并通过仿真结果验证该算法消除轴轮偏心所造成的张力干扰的能力.     

新型单相正弦车载电源

介绍了一种新型的单相正弦车载电源，该电源由单芯片产生正弦脉宽调制信号，以实现由直流12v到交流220V／50Hz的转换。给出了电源的系统结构图，详细分析了其主要部分的功能，并给出了实验结果。     

微弱正弦信号幅值混沌检测的一种改进方案

本文根据混沌系统在特定状态下对参数的敏感性,提出了一种检测微弱正弦信号幅值的改进方案.该方案采用线性最小二乘方法找到了待测微弱信号幅值与混沌动力系统特征指数之间的关系,给出了弱信号幅值的估计式.理论与数值仿真实验表明该方案的估计精度较高,计算量小,易于工程实现.     

Robust control strategies for multi-inventory systems with average flow constraints

In this paper, we consider multi-inventory systems in the presence of uncertain demand. We assume that (i) demand is unknown but bounded in an assigned compact set and (ii) the control inputs (controlled flows) are subject to assigned constraints. Given a long-term average demand, we select a nominal flow that feeds such a demand. In this context, we are interested in a control strategy that meets at each time all possible current demands and achieves the nominal flow in the average. We provide necessary and sufficient conditions for such a strategy to exist and we characterize the set of achievable flows. Such conditions are based on linear programming and thus they are constructive. In the special case of a static flow (i.e. a system with 0-capacity buffers) we show that the strategy must be affine. The dynamic problem can be solved by a linear-saturated control strategy (inspired by the previous one). We provide numerical analysis and illustrative examples.     

正交波导纵/横向耦合裂缝的散射特性

用正弦伽略金法分析了纵/横向耦合裂缝的散射特性，导出了计及波导壁厚度的积分方程。进一步分析了正交耦合的主模散射特性，分析了S参数之间的关系，计算了标准X波段矩形波导的S参数随缝隙长度、偏置的变化关系。给出了不同偏置、波导尺寸情况下谐振长度和散射特性的数值结果。这些结果已成功地应用于波导馈电裂缝阵列设计中。     

分布式虚拟环境中的三维音频支持

提出一种适用于分布式虚拟环境的三维音频生成方案，并介绍了其中的具体算法和实现，该方案利用音频信号的正弦变换中分析和合成是两个完全独立过程这一重要特性，在重新合成音频信号之前很自然地加入HRTF滤波处理，以得到特定方位的三维合成效果，受步进图形／图像传输及可扩展视频等技术的启发，进一步提出基于MPEG心理声学模型1进行匹配对的重排序，从而实现三维声步进合成的算法，基于以上算法，最后给出了分布式实现的一种可能途径并分析了该方案的优点，如可扩展性，声源方向的灵活性及HRTF可选性等。     

监测记录电源干扰的触发装置

本文介绍一种用于监测多路电源实时干扰的故障触发器。在电力系统中，将这个触发器和数字示波器配合可快速、准确测出电压波形的变化，在其它需要检测波形偏差的地方也可采用这个触发装置。     

Derivation of equivalents for dynamic security assessment

A method is described by which the order of interconnected power systems is reduced. When the system under study is composed of a main system and several subsystems connected to the main system, the method gives an equivalent model to each subsystem with far fewer generators, even when each subsystem is connected to the main system at more than one point. The paper also discusses the data that needs to be sent from each subsystem when it is expressed by a reduced-order equivalent model. A numerical example of a 250-bus and 61-machine system shows that the method is effective and causes no loss of accuracy. Although the proposed method provides an accurate reduced-order model, it is rather time-consuming, because it is based on the linearized dynamic equations of the system, and their eigenvectors are needed. This problem must be solved before practical use of the method can proceed.     

Estimation of model quality

This paper provides an introduction to recent work on the problem of quantifying errors in the estimation of models for dynamic systems. This is a very large field. We therefore concentrate on approaches that have been motivated by the need for reliable models for control system design. This will involve a discussion of efforts that go under the titles of ‘estimation in ’, ‘worst-case estimation’, ‘estimation in ℓ₁’ and ‘stochastic embedding of undermodelling’. A central theme of this survey is to examine these new methods with reference to the classic bias/variance tradeoff in model structure selection.