A fuzzy assembly line balancing problem with physical workload constraints

Although assembly lines are designed to be highly efficient and very cost effective, they have been criticised for their effects on workers. Assembly workers usually perform repetitive tasks and sit or stand for long periods of time, therefore they are at high risk of work-related injuries such as musculoskeletal disorders. In this study, we present a new assembly line balancing problem that incorporates not only task precedence and processing times but also physical workloads in order to reduce work-related injuries. We consider the physical workload of a task as a fuzzy concept and propose a fuzzy linear programming model. The proposed model is applied to an assembly line balancing problem in a textile company and to some of the benchmark problems in order to illustrate the effects of physical workloads. © 2012 Taylor & Francis