Study Of Human Reliability In Gearbox Assembly Process

With the improvement and development of scientific and technology, the degree of automation in production systems is higher and higher, the equipment reliability is better and better, operating environment is being improved largely, and every technical means is being optimized. The proportion of the accidents caused directly by hardwares has been dropped to very low levels. However,the operation of the entire production depends on the human in some way so that the people's effects on the systems are not only weaken but more protrusion and important, and the human relative error rate becomes higher and higher. So the human errors are the main reason of quality accidents and the question of human reliability is also becoming the most important factors in the system reliability. Human reliability analysis (HRA) has being developing decades, the researchers are more and more and the applications are wider and wider(For example, Nuclear power plant system, Aerospace, Transport, Chemical and so on). More and more researchers are applying it to many fields(such as Nuclear power plant systems, Aerospace, Traffic and Transportation Safety, Chemicals and so on)during the several decades in human reliability analysis. However, few scholars has paid attention to the human reliability in the manufacturing industry so far.The background of this paper is the gearbox assembly industry, and the focus of this paper is the gearbox assembly process, and the object of this paper is operator in the gearbox assembly plant, and target of this paper is to model human reliability model of the discrete manufacturing systems, this paper is in these foundation to research the Performance Shaping Factors (PSF) which affect the assembly quality of the gearbox and quantitative it. The study of this paper is to improve and apply the model of THERP+HCR.In today, the science and technology developing rapidly, the issue of human reliability has been more and more prominent in these field such as Nuclear Power Plant, Aerospace, Chemical industry, Machine instrumentation, Traffic safe and so on. After reading a lot of literature at home and abroad, we found that there were a large number of scholars, who committed to human reliability, had made plenty of research in this filed. China is a big manufacturing country, with the improving of the level of the manufacturing automation, the human reliability in manufacturing industry increasingly prominent and in the current time there are few scholars at home to concern about the issue of human reliability in manufacturing industry. In this paper we attempt to change the human reliability model and make it to suitable for the study of human reliability in the manufacturing industry, and find out the factors which impact the human reliability in the manufacturing industry.Chapterâ…¡introduced the basic concept of human error, and proposed the concept of human error in this paper after comparing the predecessors'concept about human error and combing the study practice of this paper. And this chapter also introduced the concept of human reliability and comparing human reliability with machine reliability. This chapter also including the development course of the HRA from the 20th century and some classic HRA models. There is a summary about the applications and development prospects of the HRA at the end of this chapter.In chapterâ…¢, the human error of the processes of"assembling the intermediate shaft"in the process of gearbox assembly was analyzed by model of THERP+HCR, and we got the human error probability of the processes by the predication process of the model. Before the application of model, we introduced basic theory of the model, including the origin of model, development process, features of model, and the specific application process of the model. In the application process of the model, we selected the PSF which affect the action of the operator of the processes of"assembling the intermediate shaft", and quantified the PSF by the method of Principal Component Analysis.In chapterâ…£, we analyzed and predicted the eight human errors in the process of gearbox assembly by the model of AHP-FLIM. The model of AHP-FLIM was improved from the model of SLIM, and replaced the direct judgment of the experts by the indirect judgment by the AHP. And we can keep the consistence of experts'judgment by using the technology of AHP, which is an important improvement of the SLIM.To sum up, this paper established the human reliability model in the gearbox assembly: the model of THERP+HCR and AHP-FLIM, and we studied the human errors and human reliability of the gearbox assembly process by the models. First, we improved the model of THERP+HCR, and determined the PSF suitable for gearbox assembly line. We analyzed and quantified the PSF by the method of Principal Component Analysis. The processes of"assembling the intermediate shaft"was an example of the detailed application process of the model, and we got the human error probability of this processes by the model. Second, we also improved the model of SLIM in this paper. We kept the accuracy and assistance of experts'judgment by using AHP. In the application process of the AHP-FLIM, we selected eight typical human errors in the gearbox assembly process as the study objects and six PSF according to the situation and expert advices. In the end, by analysis and predication of AHP-FLIM, we got human error probability of the eight human errors.We can apply the HRA technology to all manufacturing by the study of human reliability in the gearbox assembly. By the HRA technology, we can analyze the human error in the manufacturing, and predicate the human error probability and human reliability. According to the HRA results, we know the human errors whose occurrence probability are high, and the PSF which affect operators'reliability, and which can provide the basis to relevant departments.