Availability and cost–benefit analysis of a fault tolerant series–parallel system with human-robotic operators

Abstract

Abstract Without excellent system uptime and profit margins, many manufacturing systems will not be able to continue operating. Strong business performance of manufacturing companies is facilitated by system availability and profit generation. Most manufacturing systems are set up in series–parallel, parallel-series, or hybrid configurations. In this present study, we analyze a series–parallel system composed of two subsystems with the following specifications: subsystem A consists of two similar units/components that are operated by Human, whereas subsystem B is made up of two similar units/components that are operated by Robot. We have also introduced fault tolerance factor in this work, so that the failure of each unit in each subsystem, common cause failure as well as failure due to human error and robot, will be accompanied by this fault tolerance factor. Our key goals are to examine how fault tolerance will increase the model’s availability and profitability and to identify optimum maintenance plan. In order to meet these key goals, certain expressions for reliability metrics have been developed and validated through numerical examples. Tables and graphs are used to illustrate the results and form conclusions from them.

Keywords

• Availability
• Fault tolerance factor
• Common cause failure
• Expected profit