Detecting the position of non-linear component in periodic structures from the system responses to dual sinusoidal excitations

Based on the non-linear output frequency response functions (NOFRFs), a novel method is developed to detect the position of non-linear components in periodic structures. The detection procedure requires exciting the non-linear systems twice using two sinusoidal inputs separately. The frequencies of the two inputs are different; one frequency is twice as high as the other one. The validity of this method is demonstrated by numerical studies. Since the position of a non-linear component often corresponds to the location of defect in periodic structures, this new method is of great practical significance in fault diagnosis for mechanical and structural systems.     

Bifurcation criterion of faults in complex nonlinear systems

In this paper, we introduce bifurcation theory into complex nonlinear systems. We adopt a novel approach to identify faults in electric circuit systems. After accidents occur without warning, with large numbers of complicated and high-precision calculations, we use bifurcation results of corresponding amplitude and frequency (period) to analyze their universal characteristics. Based on super attractive parameters, we have got the universal constant 4.6692… . The results from the present investigation imply that each fault in an electric circuit system must correspond to one or more bifurcation locations, which will provide a bifurcation criterion of faults in complex nonlinear systems. This research will have a significant theoretical value and engineering practical significance.     

Actuator fault detection and estimation for the Lur’e differential inclusion system

This paper deals with actuator fault detection and estimation for the Lur’e differential inclusion system. An adaptive full-order observer is used to detect the occurrence of the actuator fault. Then, based on a reduced-order observer, an approach to estimate the actuator fault is presented. A simulation of rotor system is given to illustrate the effectiveness of the proposed method.     

模糊技术在可靠性工程中的应用

本文主要介绍模糊集合理论和技术在可靠性工程中的应用现状及其发展趋势，尤其是在系统故障诊断，故障树分析（ＦＴＡ）系统可靠性分配，人的可靠性，软件可靠性，结构可靠性以及系统安全性工程中的应用和技术关键，并从工程应用的需要出发针对存在问题预测和提出各种解决途径。     

Fault Detection of DC Electric Motors Using the Bispectral Analysis

The two major advantages of bispectral analysis are: resistance to noise and the ability to detect nonlinearities, like quadratic phase coupling. The first aim was to study some of the theoretical aspects of bispectral estimation. A lot of attention was paid to the influence of noise, the number of segments, the influence of one or several harmonic deterministic components and aliasing. These aspects are typical of rotating machinery. An example of successful fault identification in DC electric motors is presented. The identification proved to be capable to identify quadratically coupled mechanical system when the power-spectra analysis failed. Further it proved to be quite resistant to noise.     

On-line soft error correction in matrix–matrix multiplication

Soft errors are one-time events that corrupt the state of a computing system but not its overall functionality. Soft errors normally do not interrupt the execution of the affected program, but the affected computation results cannot be trusted any more. A well known technique to correct soft errors in matrix–matrix multiplication is algorithm-based fault tolerance (ABFT). While ABFT achieves much better efficiency than triple modular redundancy (TMR) – a traditional general technique to correct soft errors, both ABFT and TMR detect errors off-line after the computation is finished. This paper extends the traditional ABFT technique from off-line to on-line so that soft errors in matrix–matrix multiplication can be detected in the middle of the computation during the program execution and higher efficiency can be achieved by correcting the corrupted computations in a timely manner. Experimental results demonstrate that the proposed technique can correct one error every ten seconds with negligible (i.e. less than 1%) performance penalty over the ATLAS dgemm().     

基于PSCAD/EMTDC的高温超导电缆模型

在PSCAD/EMTDC中对国内首条110kV冷绝缘高温超导电缆建立了模型,该模型能够反映出电流在导体层和铜骨架之间的分流情况;将MATLAB与PSCAD/EMTDC通过接口程序连接,在MATLAB中编写了导体层阻值的计算程序,该程序考虑到了温度和电流的影响,能够反映出每一个采样时间段内阻值的变化情况;设置了单相接地故障,对故障电流下超导电缆的失超过程进行了仿真,得到并分析了失超过程中电流波形图以及导体层的温度曲线。