Functional healthy state evaluation approach based on phased state task network for intelligent multistation manufacturing systems

The core function of the intelligent multistation manufacturing system is to continuously and stably output a specified number of qualified products which can meet the requirements of production tasks through the machine at each station. Consequently, only the analyzing and modeling of the physical failure of the machine cannot realize the functional healthy state evaluation of the manufacturing system oriented to product quality, nor can it describe the phased degradation characteristics during the task execution. Therefore, a novel evaluation approach of the functional healthy state based on phased state task network (PSTN) theory for the intelligent multistation manufacturing systems is proposed in this study. First, the connotation of a functional healthy state of the intelligent multistation manufacturing system is expounded in combination with the performance state of each component in the system from the perspective of system engineering. Second, the PSTN of the intelligent multistation manufacturing system is established, and an integrated mission reliability model of the system is built on it. Third, a functional healthy state evaluation approach is proposed on the basis of the integrated mission reliability model and fuzzy evidence theory. Finally, a cylinder head manufacturing system is taken as an example to verify the proposed method, and sensitivity and comparative analyses are carried out to illustrate its effectiveness and advantages.