In consideration of the uncertainty of basic events failure rate and lack of probability statistical information in fault tree analysis( FTA) of excavator variable-frequency speed control system, the interval theory w...In consideration of the uncertainty of basic events failure rate and lack of probability statistical information in fault tree analysis( FTA) of excavator variable-frequency speed control system, the interval theory was employed and combined with conventional FTA method. The basic events failure probabilities were described by interval numbers,and the interval operators of logical gates in FTA were deduced based on interval theory. Finally,the reliability assessment of excavator variable-frequency speed control system was done by interval FTA method. The result shows that the interval FTA method is suitable for the complex system with insufficient failure data.展开更多
CNC machine tool is a large complex system which contains both mechanical and electrical components.As one of these components,the spindle is crucial for the performance of CNC machine tool.To improve the quality of C...CNC machine tool is a large complex system which contains both mechanical and electrical components.As one of these components,the spindle is crucial for the performance of CNC machine tool.To improve the quality of CNC machine,the reliability of spindle was evaluated in this paper using a fault tree analysis(FTA)method.The FTA method is a set of calculation methods based on Boolean algebra.However,it is difficult to analyze a large and complex fault tree with inaccurate results and low efficiency as well as the complexity of time and space.Both of them will result in the so-called "combinatorial explosion".To overcome this problem,the analysis method based on binary decision diagram(BDD)was introduced in our works,and a sorting method about bottom events was also recommended which can reduce the size of the BDD effectively.展开更多
Smart grid was proposed as a practical form of future power distribution system. Evaluating the reliability of smart grids was of great importance and significance. A revised fault tree model was proposed to distingui...Smart grid was proposed as a practical form of future power distribution system. Evaluating the reliability of smart grids was of great importance and significance. A revised fault tree model was proposed to distinguish and separate grid-connected operation mode and islanded operation mode of smart grids,focusing on the perspective of the consumers. A hierarchical Monte Carlo simulation method for reliability evaluation was also proposed based on the proposed fault tree model. A case of reliability evaluation for the future renewable electric energy delivery and management( FREEDM) system was carried out and analyzed. The proposed methods can be applicable to other forms of smart grids.展开更多
大众迈腾发动机不能起动的影响因素错综复杂,需要寻求一种新的方法来提高诊断的有效性。故障树分析法(Fault Tree Analysis,FTA)为科学诊断电控发动机这种复杂的动力机械提供了新思路。以起动控制逻辑作为构建故障树的基础,分析了迈腾B8...大众迈腾发动机不能起动的影响因素错综复杂,需要寻求一种新的方法来提高诊断的有效性。故障树分析法(Fault Tree Analysis,FTA)为科学诊断电控发动机这种复杂的动力机械提供了新思路。以起动控制逻辑作为构建故障树的基础,分析了迈腾B8L2.0T发动机从按下E378到起动机驱动齿轮带动飞轮旋转的整个过程,建立了“起动机不能运转”和“起动机运转但发动机不能起动”故障树,依据各个事件内在的控制规律设计了故障诊断流程。实验结果表明:故障树模型符合大众迈腾发动机的工作机理,根据故障诊断流程能够准确锁定迈腾发动机不能起动的故障部位。展开更多
基金National High-Tech Research and Development Program(863 Program),China(No.2012AA062001)
文摘In consideration of the uncertainty of basic events failure rate and lack of probability statistical information in fault tree analysis( FTA) of excavator variable-frequency speed control system, the interval theory was employed and combined with conventional FTA method. The basic events failure probabilities were described by interval numbers,and the interval operators of logical gates in FTA were deduced based on interval theory. Finally,the reliability assessment of excavator variable-frequency speed control system was done by interval FTA method. The result shows that the interval FTA method is suitable for the complex system with insufficient failure data.
基金National Science and Technology Major Project of China(No.2013ZX04013-011)
文摘CNC machine tool is a large complex system which contains both mechanical and electrical components.As one of these components,the spindle is crucial for the performance of CNC machine tool.To improve the quality of CNC machine,the reliability of spindle was evaluated in this paper using a fault tree analysis(FTA)method.The FTA method is a set of calculation methods based on Boolean algebra.However,it is difficult to analyze a large and complex fault tree with inaccurate results and low efficiency as well as the complexity of time and space.Both of them will result in the so-called "combinatorial explosion".To overcome this problem,the analysis method based on binary decision diagram(BDD)was introduced in our works,and a sorting method about bottom events was also recommended which can reduce the size of the BDD effectively.
文摘Smart grid was proposed as a practical form of future power distribution system. Evaluating the reliability of smart grids was of great importance and significance. A revised fault tree model was proposed to distinguish and separate grid-connected operation mode and islanded operation mode of smart grids,focusing on the perspective of the consumers. A hierarchical Monte Carlo simulation method for reliability evaluation was also proposed based on the proposed fault tree model. A case of reliability evaluation for the future renewable electric energy delivery and management( FREEDM) system was carried out and analyzed. The proposed methods can be applicable to other forms of smart grids.
文摘大众迈腾发动机不能起动的影响因素错综复杂,需要寻求一种新的方法来提高诊断的有效性。故障树分析法(Fault Tree Analysis,FTA)为科学诊断电控发动机这种复杂的动力机械提供了新思路。以起动控制逻辑作为构建故障树的基础,分析了迈腾B8L2.0T发动机从按下E378到起动机驱动齿轮带动飞轮旋转的整个过程,建立了“起动机不能运转”和“起动机运转但发动机不能起动”故障树,依据各个事件内在的控制规律设计了故障诊断流程。实验结果表明:故障树模型符合大众迈腾发动机的工作机理,根据故障诊断流程能够准确锁定迈腾发动机不能起动的故障部位。
