scholarly journals Stochastic change detection based on an active fault diagnosis approach

Author(s):  
Niels Kjolstad Poulsen ◽  
Henrik Niemann
Author(s):  
Niels Poulsen ◽  
Henrik Niemann

Active Fault Diagnosis Based on Stochastic TestsThe focus of this paper is on stochastic change detection applied in connection with active fault diagnosis (AFD). An auxiliary input signal is applied in AFD. This signal injection in the system will in general allow us to obtain a fast change detection/isolation by considering the output or an error output from the system. The classical cumulative sum (CUSUM) test will be modified with respect to the AFD approach applied. The CUSUM method will be altered such that it will be able to detect a change in the signature from the auxiliary input signal in an (error) output signal. It will be shown how it is possible to apply both the gain and the phase change of the output signal in CUSUM tests. The method is demonstrated using an example.


2006 ◽  
Vol 39 (1) ◽  
pp. 493-498
Author(s):  
Niels Kjølstad Poulsen ◽  
Henrik Niemann

Author(s):  
Jianfeng Jiang

Objective: In order to diagnose the analog circuit fault correctly, an analog circuit fault diagnosis approach on basis of wavelet-based fractal analysis and multiple kernel support vector machine (MKSVM) is presented in the paper. Methods: Time responses of the circuit under different faults are measured, and then wavelet-based fractal analysis is used to process the collected time responses for the purpose of generating features for the signals. Kernel principal component analysis (KPCA) is applied to reduce the features’ dimensionality. Afterwards, features are divided into training data and testing data. MKSVM with its multiple parameters optimized by chaos particle swarm optimization (CPSO) algorithm is utilized to construct an analog circuit fault diagnosis model based on the testing data. Results: The proposed analog diagnosis approach is revealed by a four opamp biquad high-pass filter fault diagnosis simulation. Conclusion: The approach outperforms other commonly used methods in the comparisons.


2021 ◽  
Vol 245 ◽  
pp. 114603
Author(s):  
Yongjie Liu ◽  
Kun Ding ◽  
Jingwei Zhang ◽  
Yuanliang Li ◽  
Zenan Yang ◽  
...  

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