Reliability Analysis of Main-axis Control System of the Antarctic Equatorial Astronomical Telescope Based on Fault Tree

2018 ◽  
Vol 42 (3) ◽  
pp. 448-461
Author(s):  
L.I. Yun ◽  
Yang Shi-hai
2014 ◽  
Vol 556-562 ◽  
pp. 2333-2336
Author(s):  
Shang Guan Wei ◽  
Jie Xiao ◽  
Bai Gen Cai ◽  
Jian Wang

This paper mainly studies the reliability of trackside subsystem of the CTCS-3 train control system. Dynamic fault tree method is used for reliability analysis. The fault tree is decomposed into static and dynamic sub-trees. Based on Markov method, precise quantitative analysis is performed on the dynamic sub-tree. The failure probability of the trackside subsystem is calculated. Through analyzing the structural importance degree and pivotal importance degree of the bottom events, suggestions for improving the reliability of the system are concluded.


2020 ◽  
Vol 16 (11) ◽  
pp. 1826
Author(s):  
Li Zheng ◽  
Yang Jianwei ◽  
Yao Dechen ◽  
Wang Jinhai ◽  
Pang Qicheng

Author(s):  
Fang Wang ◽  
Yong Bai ◽  
Feng Xu

Deepwater oil and gas explorations bring more safety and reliability problems for the dynamically positioned vessels. With the demands for the safety of vessel crew and onboard device increasing, the single control architecture of dynamic positioning (DP) system can not guarantee the long-time faultless operation for deeper waters, which calls for much more reliable control architectures, such as the Class 2 and Class 3 system, which can tolerate a single failure of system according to International Maritime Organization’s (IMO) DP classification. The reliability analysis of the main control station of DP Class 3 system is proposed from a general technical prospective. The fault transitions of the triple-redundant DP control system are modeled by Markov process. The effects of variation in component failure rates on the system reliability are investigated. Considering the DP operation involved a human-machine system, the DP operator factors are taken into account, and the human operation error failures together with technical failures are incorporated to the Markov process to predict the reliability of the DP control system.


2021 ◽  
Vol 11 (22) ◽  
pp. 10616
Author(s):  
Jingtian Xu ◽  
Man Yang ◽  
Shugang Li

The hardware reliability of a gas monitoring system was investigated using the fuzzy fault tree analysis method. A fault tree was developed considering the hardware failure of the gas monitoring system as a top event. Two minimum path sets were achieved through qualitative analysis using the ascending method. The concept of fuzzy number of the fuzzy set theory was applied to describe the probability of basic event occurrence in the fault tree, and the fuzzy failure probabilities of the middle and top events were calculated using fuzzy AND and OR operators. The results show that the proposed fuzzy fault tree is an effective method of reliability analysis for gas monitoring systems. Results of calculations using this method are more reasonable than those obtained with the conventional fault tree method.


2021 ◽  
Author(s):  
Shin-Ichiro Higashino ◽  
Masahiko Hayashi ◽  
Takuya Okada ◽  
Shuji Nagasaki ◽  
Koichi Shiraishi ◽  
...  

Abstract. The authors have developed a system for the Antarctic stratospheric aerosol observation and sample-return using the combination of a rubber balloon, a parachute, and a gliding fixed-wing unmanned aerial vehicle (UAV). A rubber balloon can usually reach 20 km to 30 km in altitude, but it becomes difficult for the UAV designed as a low-subsonic UAV to directly glide back from the stratospheric altitudes because the quantitative aerodynamic characteristics necessary for the control system design at such altitudes are difficult to obtain. In order to make the observation and sample-return possible at such higher altitudes while avoiding the problem with the control system of the UAV, the method using the two-stage separation was developed and attempted in Antarctica. In two-stage separation method, the UAV first descends by a parachute after separating from the balloon at stratospheric altitude to a certain altitude wherein the flight control system of the UAV works properly. Then it secondly separates the parachute for autonomous gliding back to the released point on the ground. The UAV in which an optical particle counter and an airborne aerosol sampler were installed was launched on January 24, 2015 from S17 (69.028S, 40.093E, 607 m MSL) near Syowa Station in Antarctica. The system reached 23 km in altitude and the UAV successfully returned aerosol samples. In this paper, the details of the UAV system using the two-stage separation method including the observation flight results, and the preliminary results of the observation and analyses of the samples are shown.


Author(s):  
Ahmad Khayyati ◽  
Mohammad Pourgol-Mohammad

Abstract Unmanned Aerial Vehicles (UAV) are increasingly get popularity in many applications. Their operation requires high level of safety and reliability to accomplish successful missions. In this study, the reliability was comparatively analyzed by different available approaches to select the efficient method. First, failure model of the system is developed. Then, three different scenarios are considered to study the effect of redundancies on the system reliability results. In the first scenario, there is no redundancy where in the second scenario there is only one redundant component and in the third scenario, there are three redundant components. Static reliability analysis such as Fault Tree Analysis (FTA), Reliability Block Diagram (RBD), Markov Chain (MC), and Bayesian Networks (BN) are applied on proposed scenarios and results are obtained. Regarding to time dependencies between redundant components, a dynamic-based methodology is also developed in this study through applying Dynamic Fault Tree (DFT) analysis. Proposed static and dynamic approaches are applied on an UAV as a case study and results are discussed. Finally, characteristics of each methodology and related conditions are clarified for selecting the efficient reliability analysis approach.


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