A combined technique of Kalman filter,artificial neural network and fuzzy logic for gas turbines and signal fault isolation

The target of this paper is the performance-based diagnostics of a gas turbine for the automated early detection of components malfunctions. The paper proposes a new combination of multiple methodologies for the performance-based diagnostics of single and multiple failures on a two-spool engine. The aim of this technique is to combine the strength of each methodology and provide a high success rate for single and multiple failures with the presence of measurement malfunctions. A combination of KF (Kalman Filter), ANN (Artificial Neural Network) and FL (Fuzzy Logic) is used in this research in order to improve the success rate, to increase the flexibility and the number of failures detected and to combine the strength of multiple methods to have a more robust solution. The Kalman filter has in his strength the measurement noise treatment, the artificial neural network the simulation and prediction of reference and deteriorated performance profile and the fuzzy logic the categorization flexibility, which is used to quantify and classify the failures. In the area of GT (Gas Turbine) diagnostics, the multiple failures in combination with measurement issues and the utilization of multiple methods for a 2-spool industrial gas turbine engine has not been investigated extensively.This paper reports the key contribution of each component of the methodology and brief the results in the quantification and classification success rate. The methodology is tested for constant deterioration and increasing noise and for random deterioration. For the random deterioration and nominal noise of 0.4%, in particular, the quantification success rate is above 92.0%, while the classification success rate is above 95.1%. Moreover, the speed of the data processing (1.7 s/sample) proves the suitability of this methodology for online diagnostics.     

面向功放-整流一体化设计的逆F类功率放大器

针对微波无线功率传输对于高功率处理能力的高效整流器需求,提出一种基于高效率功率放大器的功放-整流一体化设计思路。文章首先使用型号为CG2H40010F的氮化镓高电子迁移率晶体管(GaN HEMT),通过谐波控制、负载牵引等方法,设计出一款工作在2.45GHz逆F类高效率功率放大器。在高效率功率放大器的基础上基于时间反转对偶理论,通过改变逆F类功率放大器电流方向,同时结合耦合器和移相器实现了高功率容量整流电路的设计。仿真结果表明,在245GHz工作频率下,功率放大器的输入功率为28dBm时,功率附加效率达到76%,输出功率40dBm;整流电路的输入功率为41dBm时,RF-DC转换效率可达到79%,整流最佳效率大于80%,显示了整流器的高功率处理能力。引入了两个单刀双掷开关实现功率放大器和整流器的功能切换,文章对核心电路功率放大器进行了实物测试,测试结果与仿真重合较好,验证了功放-整流一体化设计的可行性。     

Solar X-ray Monitor (XSM) on-board Chandrayaan-2 orbiter

The remote X-ray fluorescence spectroscopy is a powerful technique to investigate the elemental abundances in the atmosphere-less planetary bodies. The experiment involves measuring spectra of fluorescent X-rays from lunar surface using a low energy X-ray detector onboard an orbiting satellite. Since the flux of fluorescent X-ray lines critically depend on the flux and spectrum of the incident solar X-rays, it is essential to have simultaneous and accurate measurement of X-ray from both Moon and Sun. In the context of Moon, this technique has been employed since early days of space exploration to determine elemental composition of lunar surface. However, so far it has not been possible to exploit it to its full potential due to various reasons. Therefore it is planned to continue the remote X-ray fluorescence spectroscopy experiment on-board Chandrayaan-2 which includes both lunar X-ray observations and solar X-ray observations as two separate payloads. The lunar X-ray observations will be carried out by Chandra Large Area Soft x-ray Spectrometer (CLASS) experiment; whereas the solar X-ray observations will be carried out by a separate payload, Solar X-ray Monitor (XSM). Here we present the overall design of the XSM instrument, the present development status as well as preliminary results of the laboratory model testing. XSM instrument will have two packages namely – XSM sensor package and XSM electronics package. XSM will accurately measure spectrum of Solar X-rays in the energy range of 1–15 keV with energy resolution ∼200 eV @ 5.9 keV. This will be achieved by using state-of-the-art Silicon Drift Detector (SDD), which has a unique capability of maintaining high energy resolution at very high incident count rate expected from Solar X-rays. XSM onboard Chandrayaan-2 will be the first experiment to use such detector for Solar X-ray monitoring.     

基于多路数据采集系统的继电器开关矩阵检测研究

继电器开关矩阵能在不改变硬件的情况下,通过软件灵活设置,实现多路分时等不同方式的数据采集而被广泛应用于各型号的自动测试系统中。继电器开关矩阵功能的好坏将直接影响测试的结果。针对目前人工手动无法进行继电器矩阵开关状态检测的问题,介绍了继电器开关矩阵功能的检测方法,搭建了继电器开关矩阵功能检测系统,采用计算机软件控制自动进行分析判断,完成了继电器短路故障、继电器开路故障和继电器焊点的自动检测,实现了测试的覆盖性和可靠性要求,大大提高了测试效率。     

基于串口通讯的离心机动态半径采集系统的设计

介绍了精密离心机动态半径实时数据采集与处理系统的设计。该系统通过串口接收下位机采集的实时数据,经过处理在PC机界面以实时曲线的方式显示。此动态半径采集系统在VC环境下设计实现,可实现离心机动态半径的在线检测,具有良好的直观性和实用性。     

VFC在捷联惯导数据采集系统中的应用

介绍一种以压频转换来实现捷联惯性制导系统惯性器件信号采集的方法。在本系统中以TI公司的TMS320C6711 DSP器件为核心,采用VFC型ADC转换器件AD652,利用可编程的定时器/计数器芯片8253对AD652的输出脉冲串进行计数。对系统硬件平台的方案设计和软件设计进行了分析。分析结果表明,本系统充分利用了压频转换芯片抗干扰能力强、应用灵活的优点,满足了导弹捷联惯性制导数据采集系统可靠性高的要求。     

宽带雷达中频直接采样信号数字去线性调频方法

为了改善模拟Dechirp方法的接收信号质量,降低中频直接采样匹配滤波处理的运算量,结合这两种方法的优点提出了数字Dechirp实时处理方法。通过理论分析与推导得出数学模型,再从实现的角度详细分析了数据抽取、滤波器设计等问题,同时介绍了适用于数字Dechirp的系统失真补偿方法。仿真与实测数据证明该方法是一种可行、高效的实时脉冲压缩方法。     

一种针对液体火箭发动机可靠性的双线评估方法

针对液体火箭发动机可靠性评估过程中试验数据利用不充分、主观性强、与设计改进关联不足等现状,给出了一种可靠性双线评估方法,在有限试车条件下提升可靠性评估结果的准确性,并从风险控制角度识别出发动机的薄弱环节.该方法采用两条主线开展可靠性评估,第一条线以发动机部组件试验数据为输入,以发动机工作时序为线索,识别发动机故障模式,...     

无线电高度表近地测高异常分析及改进

对于轮式起降无人机而言,起降阶段相对高度的准确性对无人机的飞行安全至关重要。针对高速无人机无线电高度表近地测高出现高度拾升和饱和现象,从无线电高度表测高机理出发,深入分析高度跳变的原因,针对问题现象,在不改变安装高度的前提下,提出一种低高度变增益的方法,降低高度饱和噪声的优化措施,有效提高了无线电高度表近地测高的稳定性。通过吊高试验及地面滑行试验表明,优化措施能合理有效解决高度表近地高度测量异常的问题。     

设计模式在可复用数据处理软件中的应用

针对航天测控任务数据处理软件需求易变化、可靠性要求高的特点,采用面向对象的思想,利用典型的设计模式设计并实现了一种可复用的通用数据处理软件。从软件结构上看,应用设计模式,高层组件和低层组件有机、高效地结合,形成松耦合高内聚的架构,使软件具备很好的可读性和可维护性,达到了可复用的要求。