The method for risk evaluation in assembly process based on the discrete-time SIRS epidemic model and information entropy

In the past decade years, much attention has been attached on assembly process reliability in manufacturing system, because the quality and cost of product are highly determined by assembly process. However, existing research on reliability in assembly are mainly focused on study of size deviation propagation. In this paper, the method for risk evaluation in assembly process based on the discrete-time SIRS epidemic model and information entropy was proposed. Firstly, aiming at the issue of assembly process optimization, innovative solutions are proposed from the perspectives of reliability and cost by decomposing the assembly into general path and rework path. Secondly, the propagation mechanism of defects in optimal assembly approach were studied through combining the infectious disease model and information entropy. According to the bifurcation phenomenon in the SIRS model, the entropy increment of assembly process ΔH_base when defect emergence occurs is calculated. Thirdly, the information entropy increment of optimal assembly approach DH is used to evaluate the assembly risk by comparing with the ΔH_base. Finally, a case study of assembly risk evaluation for the oil pump was presented to verify the advantage of this method.