A new diversity induction mechanism for a multi-objective ant colony algorithm to solve a real-world time and space assembly line balancing problem

Time and space assembly line balancing considers realistic multi-objective versions of the classical assembly line balancing industrial problems. It involves the joint optimisation of conflicting criteria such as the cycle time, the number of stations, and/or the area of these stations. The different problems included in this area also inherit the precedence constraints and the cycle time limitations from assembly line balancing problems. The presence of these hard constraints and their multi-criteria nature make these problems very hard to solve. Multi-objective constructive metaheuristics (in particular, multi-objective ant colony optimisation) have demonstrated to be suitable approaches to solve time and space assembly line balancing problems. The aim of this contribution is to present a new mechanism to induce diversity in an existing multi-objective ant colony optimisation algorithm for the 1/3 variant of the time and space assembly line balancing problem. This variant is quite realistic in the automative industry as it involves the joint minimisation of the number and the area of the stations given a fixed cycle time limit. The performance of our proposal is validated considering ten real-like problem instances. Moreover, the diversity induction mechanism is also tested on a real-world instance from the Nissan plant in Barcelona (Spain). This work is supported by the UPC Nissan Chair and the Spanish Ministerio de Educación y Ciencia under project DPI2007-63026 and by the Spanish Ministerio de Ciencia e Innovación under project TIN2009-07727, both including EDRF fundings. Manuel Chica, Oscar Cordón and Sergio Damas European Centre for Soft Computing 33600 Mieres, Spain E-mail: {manuel.chica,oscar.cordon,sergio.damas}@softcomputing.es Joaquı́n Bautista Nissan Chair Universitat Politècnica de Catalunya Barcelona, Spain E-mail: [email protected]