基于异步切换多胞系统的网络化飞行器故障检测

本文研究了存在时变短时延和随机丢包的大包线网络化飞行器故障检测问题.首先,采用切换多胞系统描述飞行动态,并提出了一种局部重叠多胞划分方式以较低设计保守性.然后,借助泰勒级数展开和伯努利分布将时延和丢包转化为多胞系统参数,并构建了切换参数依赖故障检测滤波器.同时,考虑滤波器切换指令及多胞加权参数更新滞后引起的异步切换问题,基于切换参数依赖Lyapunov函数和平均驻留时间方法分析了系统的稳定性和l2性能,并以LMI形式给出了滤波器存在的充分条件.最后,以HiMAT(highly maneuverable technology)飞行器为例验证了所提方法的有效性.     

低压配电系统中CAN通信适配器设计

针对异构网络不能互联互通及CAN总线传输数据量小,高速传输分包数据丢包等问题,提出一种基于透明传输和分包重组规则且适用于低压配电系统的CAN通信适配器。通过采用分包重组规则使CAN可发送数据达378 B,采用透明传输理论实现遵从Modbus协议的智能低压电器通过CAN总线简单、实时集中监控;通过研究不同波特率下适配器发送数据的延时时间,采用软件实时修正的方法避免高速发送分包数据时数据丢包。利用该适配器组建小型智能系统进行测试,结果表明,测控数据传输准确无误,实时性高,满足智能低压配电的需要。     

基于80 C196KC单片机的Smith伺服控制器

讨论全数字伺服系统中的时间滞后，通过Smith预估控制器补偿系统中的时间滞后，提出一种应用80C196KC单片机的宽范围、高精度调速的控制方案及算法。对于非滞后系统采用Smith伺服控制器，可以简化系统、提高性能指标。     

具有时延和丢包的NCS鲁棒H∞控制

针对一类含有不确定参数的网络控制系统(NCS),研究网络中存在时延与丢包情况下的鲁棒?∞控制问题.构造一个新的Lyapunov-Krasovskii泛函,并基于改进的Wirtinger不等式推导出闭环NCS渐近稳定且满足?∞性能的充分条件,该条件能得到比已有文献保守性更小的结果.给出线性锥补算法以实现次优鲁棒?∞控制器增益的求解.最后通过多个数值实例验证了所提出方法的有效性.     

一种基于过零点的时延测量方法

信号传输时间（时延）的测量,是雷达、声纳系统的关键技术之一。本文研究了一种基于过零点的时延测量方法,在建立过零点搜索模型的基础上推导得出时延测量的测量结果表达式;定量分析了高斯白噪声条件下过零点时延测量的测量精度,得到测量误差的理论表达式。仿真与实验表明,过零点时延测量精度与信号频率、过零点数目、信噪比密切相关,当信噪比较高时,其测量精度与经典FFT法相当,而优势在于过零点时延测量的算法简单、计算量小,适用于对实时性要求较高的测量场合。     

基于神经网络的常压塔柴油凝点软测量的研究与应用

研究某炼油厂常压塔三线柴油凝点的软测量建模问题,分析过程变量对柴油凝点的影响。基于在线分析仪6min采样数据,利用前向网络和时延前向网络(TDNN)分别建立了三线柴油凝点的静态软测量模型和动态软测量模型,并结合在线分析仪对模型实现了在线修正。通过两种模型的仿真和在线实施效果,表明基于神经网络的软测量模型取得了较好的应用效果,而且动态模型的实施效果优于静态模型。     

Multirate control with incomplete information over Profibus-DP network

When a process field bus-decentralized peripherals (Profibus-DP) network is used in an industrial environment, a deterministic behaviour is usually claimed. However, due to some concerns such as bandwidth limitations, lack of synchronisation among different clocks and existence of time-varying delays, a more complex problem must be faced. This problem implies the transmission of irregular and, even, random sequences of incomplete information. The main consequence of this issue is the appearance of different sampling periods at different network devices. In this paper, this aspect is checked by means of a detailed Profibus-DP timescale study. In addition, in order to deal with the different periods, a delay-dependent dual-rate proportional-integral-derivative control is introduced. Stability for the proposed control system is analysed in terms of linear matrix inequalities.     

Stability analysis and controller design of interval type-2 fuzzy systems with time delay

The type-2 fuzzy models can handle the system uncertainties directly based on the type-2 fuzzy sets. In this paper, the Takagi–Sugeno fuzzy model approach is extended to the stability analysis and controller design for interval type-2 (IT2) fuzzy systems with time-varying delay. Delay-dependent robust stability criteria are developed in terms of linear matrix inequalities by using the improvement technique of free-weighting matrices. Less conservative results are obtained by considering the information contained in the footprint of uncertainty. Finally, two simulation examples are presented to illustrate the effectiveness of the theoretical results. One is provided to show the merits of the proposed method, the other based on the continuous stirred tank reactor model is given to illustrate the design processes of IT2 fuzzy controller for a nonlinear system with parameter uncertainties.     

Three stage trade credit policy in a three-layer supply chain–a production-inventory model

The main purpose of this paper is to investigate the optimal replenishment lot size of supplier and optimal production rate of manufacturer under three levels of trade credit policy for supplier–manufacturer–retailer supply chain. The supplier provides a fixed credit period to settle the accounts to the manufacturer, while the manufacturer gives a fixed credit period to settle the account to the retailer and the retailer, in turn, also offers a credit period to each of its customers to settle the accounts. We assume that the supplier supplies the raw material to the manufacturer and sends back the defective raw materials to the outside supplier after completion of inspection at one lot with a sales price. The system always produces good items in the model. Also, we consider the idle times of supplier and manufacturer. Finally, numerical examples are provided to illustrate the behaviour and application of the model with graphical simulation.     

Allowable delay bound for consensus of linear multi-agent systems with communication delay

This paper studies the consensus of a group of linear dynamic agents with a uniform communication delay and focuses on searching an allowable delay bound. As long as the delay is less than this bound, there exist linear feedback consensus protocols driving the multi-agent system to achieve consensus. Both fixed and switching topology cases are investigated. In both cases, the consensus problem is converted to the robust stability problem of corresponding uncertain state-delayed systems. By using Lyapunov–Krasovskii functional analysis, consensus conditions which contain the feedback gain conditions and delay conditions are proposed for systems over fixed and switching topologies, respectively. Furthermore, allowable delay bounds are obtained for both systems by solving the optimal robust stabilisation problems. Numerical examples are given to illustrate the results.