Optimization Research On Workplace Facility Layout Problem Based On Human Factors

This research is focused on the workplace facility layout problem (FLP) involving manual material handling. By combining the human factors and material flow in workplace, a set of systematic methodology for analyzing, designing and evaluating workplace FLP was developed, in which both human factors and material flow were integratively optimized.First of all, the index system based on human factors for evaluating workplace layout was proposed, including three aspects of performance measurements, physiological measurements and subjective measurements, which systematically reflects the working performance and the physical and mental stress imposed on the workers. The proposed index system comprehensively assesses both the human factors and material flow in workplace. It gets rid of unilateralism existed in former studies, which emphasizes only efficiency and cost of material flow in workplace. Secondly, as the shortcomings in former studies for assessing manual material handling, the concept and quantitative model of physical workload index were proposed. From the aspects of posture, exertion, difficulty and psychological stress imposed on workers, the index comprehensively assesses the risk of physical and mental disorders on workers. The experimental results reveal that physical workload index can comprehensively reflect the risk of injuries and disorders imposed on workers by manual material handling in workplace.Thirdly, the theoretical and mathematical model of workplace FLP were developed. The theoretical model gives the technical route of analyzing and designing workplace facility layout. The new mathematical model and related restrictions provide a novel quantitative tool for solving workplace FLP. A typical workplace FLP was simulated by using the ERGO software. The results confirm the validity of proposed model.At last, present genetic algorithms cannot effectively model the workplace FLP. An improved genetic algorithm was developed based on a new encoding method and mutation operator. The algorithm provides better representation of the facility layout, enhances the efficiency of the calculation and dramatically reduces the number of illegal offsprings generated during the evolutionary process. In addition, the algorithm dynamically decides the number of rows for the workplace facilities, which removes the restriction of one-dimensional optimization in old algorithms. The algorithm optimizes workplace layouts in two dimensions. The effectiveness of the proposed algorithm was evaluated with a typical layout problem. The results show that the algorithm has good global searching ability and rapid convergence.This research is focused on the optimization of workplace facility layout, in which quantitative human factors are incorporated. This research advances the field of workplace FLP and has the guiding effect for the future study in this area. In short, this research will have significant influence on the future research direction in the field of workplace FLP.