APPLICATION OF FUZZY LOGIC TO DFA TIME MEASUREMEN

摘要

Boothroyd and Dewhurst have developed a Design ForrnAssembly (DFA) method to successfully help designersrnredesign their products. A major barrier to DFA is usuallyrnassembly time measurement. In order to reduce evaluationrnprocess and time, the DFA method must be developed anrneffective and efficient method to measure the partrnassemblability. For the assembly of any two parts, thernanalysis is broken down into two categories, insertion timernand handling time. However, these DFA time tables can notrnfit all the industrial assembly situations and assemblyrnconditions. In this paper, a fuzzy logic method is proposedrnfor manipulating the characteristic fuzziness of insertion andrnhandling difficulty problems. A knowledge based DFArnsystem is also presented to analyze manual assembly forrndifferent assembly situations and conditions. The systemsrninclude the measurement modules for shape symmetry,rndimensions, features, insertion difficulties, and handlingrndifficulties. From the experimental example, we may realizernthat fuzzy logic is a suitable methodology for modeling DFArntime measurement.