ASSEMBLY LINE BALANCING PROBLEM WITH HIERARCHICAL WORKER ASSIGNMENT, POSITIONAL CONSTRAINTS, TASK ASSIGNMENT RESTRICTIONS AND PARALLEL WORKSTATIONS

In this paper, we consider the assembly line balancing problem with hierarchical worker assignment, positional constraints, workstation paralleling options and task assignment restrictions. The objective of this problem is to decide on the number of parallel stations to be opened in each work stage and to assign tasks and workers to stations such that the sum of workstation opening costs and worker costs is minimized To solve this problem, we initially propose an integer programming model and then develop a simulated annealing algorithm hybridized with a local search procedure. A set of test problems are solved using the proposed IP model, original simulated annealing and hybrid simulated annealing algorithms. The computational results show the effectiveness and efficiency of the proposed hybrid simulated annealing algorithm.