Nonlinear aircraft sensor fault reconstruction in the presence of disturbances validated by real flight data

This paper proposes an approach for Inertial Measurement Unit sensor fault reconstruction by exploiting a ground speed-based kinematic model of the aircraft flying in a rotating earth reference system. Two strategies for the validation of sensor fault reconstruction are presented: closed-loop validation and open-loop validation. Both strategies use the same kinematic model and a newly-developed Adaptive Two-Stage Extended Kalman Filter to estimate the states and faults of the aircraft. Simulation results demonstrate the effectiveness of the proposed approach compared to an approach using an airspeed-based kinematic model. Furthermore, the major contribution is that the proposed approach is validated using real flight test data including the presence of external disturbances such as turbulence. Three flight scenarios are selected to test the performance of the proposed approach. It is shown that the proposed approach is robust to model uncertainties, unmodeled dynamics and disturbances such as time-varying wind and turbulence. Therefore, the proposed approach can be incorporated into aircraft Fault Detection and Isolation systems to enhance the performance of the aircraft.     

Multi-objective voltage and frequency regulation in autonomous microgrids using Pareto-based Big Bang-Big Crunch algorithm

Voltage and frequency regulation is one of the most vital issues in autonomous microgrids to ensure an acceptable electric power quality supply to customers. In this paper, a real-time control structure including power, voltage, and current control loops is proposed for microgrid inverters to restore voltage and frequency of the system after the initiation and load changes. The Proportional-Integral (PI) gains of the voltage controller are optimized in a real-time basis after a perturbation in the microgrid to have a fast and smooth response and a more stable system. The current controller produces Space Vector Pulse Width Modulation command signals to be fed into the three-leg inverter. The multi-objective optimization problem has objective functions of voltage overshoot/undershoot, rise time, settling time, and Integral Time Absolute Error (ITAE). The modified Multi-Objective Hybrid Big Bang-Bing Crunch (MOHBB-BC) algorithm is employed as one of efficient evolutionary algorithms in order to solve the optimization problem. The MOHBB-BC method obtains a set of Pareto optimal solutions; a fuzzy decision maker is used to pick up the most preferred Pareto solution as the final solution of the problem. Results from testing the control strategy on a case study are discussed and compared with previous works; according to them, the proposed method is able to obtain dynamic PI regulator gains to have a more appropriate response.     

求解圆盘图中最小连通支配集的近似算法

针对无线传感器网络常用的拓扑模型单位圆盘图,提出了基于分布式贪心策略的近似算法DDT,在算法执行的每一轮中,根据一跳邻域范围内的权值和邻居的状态信息,选举出节点并和已确定的节点连接,逐步构造出网络图中的一个支配树。用概率方法研究了支配树中的节点度的性质,通过对极大独立集和最小连通支配集之间关系的分析,得到单位圆盘图中最小连通支配集问题一个新的近似比。计算结果表明,和相关的分布式算法相比,DDT产生的连通支配集在规模上更优。     

基于通用分组无线业务短信控制的LED点阵屏设计

为满足中小商家的使用需求,给出了一种低成本、内容更新便捷的远程控制点阵LED文字显示屏的方案。该系统采用单片机(MCU)作为系统处理核心,采用 GPRS/GSM通信标准,通过显示屏上通用分组无线业务(GPRS)模块接收手机发送的控制命令及显示数据,经处理后控制LED显示屏的扫描显示,实现点阵屏远程更新显示内容。经一段时间的使用,系统运行稳定可靠,基本达到设计要求。     

两种工作电源的设计与实现

给出了直流稳压电源和逆变电源的设计方案。直流稳压电源具有两路±1 5 V,两路±1 2 V,两路±5 V和一路1.25～37V连续可调七路输出,每路输出电流最大可达1.5A;逆变电源输出功率可达250VA。经测试,这两种电源输出精确,稳定性好,是一种理想的实验室或家用电源。     

基于PLC变频控制系统在反渗透海水淡化装置中的应用

介绍了以西门子S72400为核心的变频控制系统在反渗透海水淡化装置中的应用,给出了控制系统的工作原理、硬件集成和软件设计方法。     

SPARC体系结构的操作系统仿真器实现方法研究

在CPU的研制阶段通常也要同时进行操作系统的开发,为在新型CPU问世之前运行和调试目标操作系统,就必须开发支持操作系统功能的CPU仿真器。文章针对一种正在研制的基于SPARC体系结构的CPU,提出了操作系统仿真器的两种实现方案,然后对其中一种相对可行的方案进行了深入研究,并总结了开发过程中解决的一些实际问题。     

基于ATM和Internet的视频点播系统的设计与实现

本文探讨了基于ATM和Internet传输视频点播业务系统的基本原理和实验实现。该系统由业务代理器和交互工作单元组成,业务代理器控制系统内的资源分配及业务指南,交互工作单元在代理器的控制下实现各种功能转换,包括：数据传输协议转换、比特率控制、业务网关转换、业务量监测。     

基于VSAT的移动指挥系统

通过一个实例介绍基于VSAT的移动指挥系统的设计,阐述了系统的基本结构单元与数据接口,最后,指出系统建设的注意要点。     

基于模拟对象Mock Object的单元测试研究

在软件测试中,单元测试不仅能够优化软件系统设计,还大大简化了功能测试的测试量。但是在一些情况下进行单元测试比较困难,本文引入了模拟对象Mock Object的概念,利用Mock Object进行单位测试,解决了传统单元测试中存在的一些问题。