Iterative beam search for simple assembly line balancing with a fixed number of work stations

Abstract

The simple assembly line balancing problem (SALBP) concern s the assignment of tasks with pre-defined processing times to work stations that are arran ged in a line. Hereby, precedence constraints between the tasks must be respected. The optimi zation goal of the SALBP-2 variant of the problem concerns the minimization of the so-called cy cle time, that is, the time in which the tasks of each work station must be completed. In this work we p ropose to tackle this problem with an iterative search method based on beam search. The propose d algorithm is able to generate optimal solutions, respectively the best upper bounds, for 283 out of 302 test cases. Moreover, for 9 further test cases the algorithm is able to improve the c urrently best upper bounds. These numbers indicate that the proposed iterative beam search al gorithm is currently a state-of-the-art method for the SALBP-2