Analysis System Development Based On FMECA And FTA For Welding Robots

With the development of industrial technology, welding robots have been widely applied. Because of its complex structure and increasingly powerful function, it becomes more and more difficult to analyse the system reliability of welding robots. In order to overcome such defects, it is necessary to develop a set of corresponding reliability analysis system and realize the automation of system reliability analysis for welding robots. Failure Mode Effects and Criticality Analysis(FMECA) and Fault Tree Analysis(FTA) are two important methods in system reliability analysis. FMECA analyses the failure situation of the key parts which affect system function and takes measures to improve design. FTA analyses various combinations of factors and probability, including hardware, software, environmental and artificial factors, which may cause system failure and takes measures to improve system reliability.The structure and function for bulk system of welding robots is analysed and the model of FMECA and FTA for welding robot system is established in this paper. FMECA table is established and qualitative and quantitative analysis is implemented by using FTA method. In order to realize the corresponding function in computer, semanderes algorithm is combined with prime method for qualitative analysis and minimal cut sets are disjointed by using admissible and repelling law for quantitative analysis in fault tree analysis. The FMECA and FTA analysis system is designed and developed for welding robots based on Visual Basic6.0, Access2003, object-oriented programming, data structures and algorithms, database design and so on. From the implementation of FMECA to the report output, from the establishment of fault tree to qualitative analysis, quantitative analysis and the output of analysis results, the software system is able to analyse series system, parallel system and2/3redundancy system. The software system also integrates FMECA and FTA and sets passwords for the database and the fault tree file to meet the requirements of information security and confidentiality.The software system has a friendly interface, complete function and simple operation. The software analysis results and artificial results are consistent and the function of saving information resources and improving the analysis efficiency is achieved.