Balanceable assembly lines with dynamic tool sharing and best matching decisions—a collaborative assembly framework

Abstract

A Collaborative Assembly Framework (CAF), inspired by the design principles of the Collaborative Control Theory, is developed in this article to enhance the extent of balancing of assembly lines. The notion of the CAF lies in the dynamic utilization of idle resources to eliminate bottlenecks. The CAF is composed of two modules: the first one, the Tool Sharing Protocol (TShP), makes dynamic tool-sharing decisions among fully loaded (i.e., bottleneck) and partially loaded Work Stations (WSs), and the second one, the Best Matching Protocol (BMP), dynamically matches tasks and WSs (BMP-1) and partially and fully loaded WSs for tool sharing (BMP-2). A Multi-Objective Mixed-Integer Programming model is developed for mathematical representation and a Fuzzy Goal Programming approach is applied for optimization purposes. The objectives are to minimize (i) the number of WSs, (ii) cycle time, and (iii) the total collaboration cost. The developed CAF is proven to guarantee the relative extent of balancing of assembly lines, depending on pairwise tool compatibility and tool-sharing performance. Numerical experiments on a set of small-sized case studies repeated and expanded from previous research show the superiority of the CAF over the existing non-collaborative approaches in terms of line efficiency, utilization, and balancing.