Availability modeling and optimization of reconfigurable manufacturing systems

摘要

Reconfiguration mechanisms lead to the design of robust manufacturing systems which have the capability to allow the service continuity,in the presence of a failure,on the basis of a minimal degradation of performances.In this paper,a stochastic model is proposed to assess and to analyze the availability of reconfigurable systems whose equipments are subject to random failures.To distinguish between the normal behavior and the desraded one,the production rate is used as a performance measure.An availability model that takes into account the performance degradation is developed.Close form solutions of the steady-state availability and the production rate of a reconfigurable system are calculated.Two optimization problems dealing with reconfigurable systems are also addressed.The paper considers a series system consisting of N stochastically independent components.Different technologies are assumed to be available for each component.The following design problems are studied:find the configuration,which allows maximizing the production rate of the system under resource constraints;and find the configuration that allows to reach some predetermined level of production rate at minimal cost.The design model of the first problem leads to mixed linear programming,while the design model of the second problem leads to integer linear programming.A numerical procedure is developed to solve both problems.