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Lu C.,Science and Technology on Reliability and Environment Engineering Laboratory
Proceedings of the World Congress on Intelligent Control and Automation (WCICA) | Year: 2016

This paper presents a rolling bearing fault diagnosis approach based on the combination of Ensemble Empirical Mode Decomposition (EEMD), Information Entropy (IE) and Support Vector Machine (SVM). The horizontal and vertical vibration signals of the bearings are utilized as the input of the method. First, the signals, after preprocess, are decomposed into certain number of intrinsic mode functions (IMF) using EEMD. Second, the IEs of the IMFs are calculated as the features for further fault diagnosis. Third, the selected features are adopted to train the SVM model using 10-fold cross validation. Fourth, the trained SVM model is used to conduct bearing fault diagnosis. To verify the effectiveness of the proposed approach, three types of faults including inner-ring fault, outer-ring fault and rolling element fault are injected and data from three individual experiments are used. The results demonstrate that the approach has desirable diagnostic performance both for cylindrical roller bearing and deep groove ball bearing. © 2016 IEEE.


Guo J.-B.,Beihang University | Guo J.-B.,Science and Technology on Reliability and Environment Engineering Laboratory | Du S.-H.,Beihang University | Wang X.,Beijing Institute of Environment Features | And 2 more authors.
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2015

The failure propagation in dynamic systems is driven by discrete component fault events, continuous processes as well as their interactions. This hybrid feature of the fault propagation brings about the difficulty in fault cognition and modeling. Existing researches regard faults just as discrete events. Thus they only focus on analyzing how the discrete system failures are caused by random component failures. However, the continuous processes in fault propagation have always been ignored for the sake of simplifications in engineering, which leads to the inaccuracy of the description of dynamic system failures. This paper defines the hybrid failure propagation within two dimensions for the dynamic system, and analyzes its hybrid factors and propagation features. For accurate description of these hybrid features, a hybrid failure propagation modeling method is proposed based on the hybrid theory which is used to model the interaction of discrete events and continuous processes. The proposed method is applied to a temperature control system. The simulation results show the hybrid feature of the failure propagation, as well as the feasibility of the presented modeling method. ©, 2015, Chinese Institute of Electronics. All right reserved.


Zhao J.,Beihang University | Sun G.,Beihang University | Zeng S.,Beihang University | Zeng S.,Science and Technology on Reliability and Environment Engineering Laboratory | And 3 more authors.
Journal of Mechanical Science and Technology | Year: 2016

The accidents of many share-control engineering application, including the aircraft carrier-landing process, are directly related to human error. In order to identify human error and assess the reliability of Human system interaction (HSI) in carrier landing, a control theoretic based simulation method is proposed. The simulator combines the pilot control with the cognition model that exploits the human error mechanism to describe the dynamic characteristics of carrier-landing. And the Performance shaping factors (PSFs) are also taken into consideration to represent the likelihood of human error. Moreover, the mission reliability is proposed as an appropriate metric of HSI. By quantitative simulation, the human error produced in HSI could be presented and demonstrated dynamically. The performance of the proposed method is tested through a case study. © 2016, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.


Liu H.,Beihang University | Li D.,Beihang University | Lu C.,Science and Technology on Reliability and Environment Engineering Laboratory | Liu D.,China Aeronautical Radio Electronics Research Institute
Proceedings of the World Congress on Intelligent Control and Automation (WCICA) | Year: 2016

Hydraulic servo system is widely used in the project, and it's crucial for the reliability of hydraulic system. Due to the nonlinear, time-varying and noise in the hydraulic system, the traditional fault diagnosis methods have been unable to meet the requirements. To decrease false alarm rate of hydraulic servo system, an adaptive fault detection method based on RBF observer and an adaptive threshold is presented. First, an RBF observer is established to obtain the residual by subtracting actual output from the estimated output by observer. Second, input command signal and output displacement signal of hydraulic servo system were decomposed into different wavelet frequency band which was input RBF neural network to get time-frequency adaptive threshold. Third, fault is detected by comparing the residual with adaptive threshold. Lastly, experimental results demonstrated that the proposed method is effective in detecting fault of hydraulic servo system. © 2016 IEEE.


Du X.,Science and Technology on Reliability and Environment Engineering Laboratory | Zeng S.,Science and Technology on Reliability and Environment Engineering Laboratory | Zeng S.,Beihang University | Guo J.,Science and Technology on Reliability and Environment Engineering Laboratory | Guo J.,Beihang University
Proceedings of 2014 Prognostics and System Health Management Conference, PHM 2014 | Year: 2014

Traditional system reliability model has almost neglected the coupling between different states (normal, failures, etc) and the continuous variation process of performance. This paper presents a method of system reliability modeling based on hybrid Petri nets (HPN), which combines the discrete state and continuous performance together during the system to describe the coupling relationship. Firstly, the system normal running mode and fault mode were established using HPN to describe the logical relationship between the discrete states; Secondly, on account of each discrete state, the corresponding continuous performance models were established and uncertain external influencing factors were introduced. Besides, The degradation process can be described by transitions among discrete states and physical modeling by (physical) equations that govern the degradation process. And the time-dependent transition rates associated with model parameters were introduced to describe the switch as a bridge between discrete states and continuous performance characteristics; Finally, the running mechanism were considered and a hydraulic case was modeled by this method. © 2014 IEEE.


Liu Z.,Science and Technology on Reliability and Environment Engineering Laboratory | Zeng S.,Science and Technology on Reliability and Environment Engineering Laboratory | Zeng S.,Beihang University | Guo J.,Science and Technology on Reliability and Environment Engineering Laboratory | Guo J.,Beihang University
Proceedings of 2014 Prognostics and System Health Management Conference, PHM 2014 | Year: 2014

The reliability analysis of systems may be very time-consuming by traditional sampling algorithms such as Monte Carlo especially for dynamic systems, because the states of dynamic systems are time-dependent. We address this main problem of dynamic systems with a new reliability analysis method based on stochastic reachability which has been studied in the field of control theory and control engineering. Randomness in dynamic systems will be described by this approach. It is involved from the following two aspects. One is to use jumps involving probability distributions when settling the time automata model. This adds the possibility to represent component failures. Another aspect is to put stochastic differential equation components inside the dynamic system models. By doing that, the impact of external disturbances such as environmental temperature can be taken into consideration. © 2014 IEEE.


Qin W.-L.,Beihang University | Zhang W.-J.,Beihang University | Lu C.,Science and Technology on Reliability and Environment Engineering Laboratory
Vibroengineering Procedia | Year: 2015

This paper presents a rolling bearing fault diagnosis approach based on the combination of Ensemble Empirical Mode Decomposition (EEMD), Information Entropy (IE) and Random Forests (RF). The horizontal and vertical vibration signals of the bearings are utilized as the input of the method. First, the signals, after preprocess, are decomposed into certain number of intrinsic mode functions (IMF) using EEMD. Second, the IEs of the IMFs are calculated as the features for further fault diagnosis. Third, the selected features are adopted to train the random forests model using 10-fold cross validation. Fourth, the trained RF model is used to conduct bearing fault diagnosis. To verify the effectiveness of the proposed approach, three types of faults including inner-ring fault, outer-ring fault and rolling element fault are considered and data from two individual experiments are used. The results demonstrate that the approach has desirable diagnostic performance both for cylindrical roller bearing and deep groove ball bearing. © JVE International Ltd.


Wang P.,Science and Technology on Reliability and Environment Engineering Laboratory | Zhang J.,Science and Technology on Reliability and Environment Engineering Laboratory | Lu Y.,Science and Technology on Reliability and Environment Engineering Laboratory | Liu Y.,Institute of Spacecraft System Engineering
RQD 2014 - Proceedings - 20th ISSAT International Conference Reliability and Quality in Design | Year: 2014

Aiming at the hybrid uncertainty in complex mechanism system, this paper presents a new hybrid reliability model which contains randomness, fuzziness and non-probabilistic uncertainty based on the hybrid Bayesian network. By solving the hybrid uncertainty quantification and propagation problems in complex mechanism system in a hierarchical way from simple components to subsystems, the hybrid reliability can be obtained. For illustration and validation the purpose, an example of two a xis position mechanism is demonstrated in details. The results show that the presented hybrid model, which may ensure mechanism security, is effective and practical.


Li M.,Science and Technology on Reliability and Environment Engineering Laboratory | Zhang J.,Science and Technology on Reliability and Environment Engineering Laboratory | Si J.,Science and Technology on Reliability and Environment Engineering Laboratory | Wang P.,Science and Technology on Reliability and Environment Engineering Laboratory | Yan J.,Science and Technology on Reliability and Environment Engineering Laboratory
RQD 2014 - Proceedings - 20th ISSAT International Conference Reliability and Quality in Design | Year: 2014

The space mechanism system is a typical complex mechanism system with problems of cascade-coupling reliability. Traditional probability design theories of reliability cannot meet the need of the cascade-coupling reliability design for complex space mechanism system. To solve this problem, this paper provides a new thought by combining the theories of axiomatic design and reliability design, using zigzag mapping to make cascade decomposition for each layer of sub-systems in complex space mechanism system, analyzing the internal coupling design parameters related to reliability design in complex space mechanism system by combining independence axiom, reducing the coupling degree, and the iterations, defining system reliability from a function delivery perspective that lays the foundation for reliability improvement in the concept design stage. To provide method for the safety and reliability of the complex space mechanism system, the theoretical value and engineering significance of proposed method is demonstrated by an illustrative example showing cascade-coupling reliability design of a typical mechanism.


Huang J.,Beijing Institute of Spacecraft Environment Engineering | Huang J.,Science and Technology on Reliability and Environment Engineering Laboratory | Liu G.,Beijing Institute of Spacecraft Environment Engineering | Liu G.,Science and Technology on Reliability and Environment Engineering Laboratory | And 2 more authors.
Journal of Geophysical Research A: Space Physics | Year: 2015

For disturbed geosynchronous plasma, the onset of spacecraft charging and its evolution become more complex than quiet environment. A sudden jump of spacecraft potential can occur in specific environment conditions which can be detrimental to onboard electronics. In this paper, the potential jump for geosynchronous spacecraft charging is theoretically modeled and comprehensively characterized. Two types of potential jump in opposite directions are elucidated, and the threshold conditions for both types of jump are determined. At both thresholds, the spacecraft potentials are semisteady, but in opposite directions, with the possibility of a jump to a stable potential. The polarity of movement across the thresholds from different plasma will cause a spacecraft to experience irreversible charging histories which result in significant hysteresis. Generally, the jump to negative potential occurs with greater magnitude as compared to a potential jump in positive direction. Ion distribution has negligible influence to the threshold condition for jump to negative potential. However, ion distribution significantly affects the threshold for jump to positive potential and subsequently modifies the parametric domains of spacecraft charging. ©2015. American Geophysical Union. All Rights Reserved.

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