关键词: 约束理论, 瓶颈能力释放率, 瓶颈能力释放区, 作业车间调度问题, 鲁棒性, 随机扰动

Abstract: Owing to the 100% utilization of bottleneck machine, job shop scheduling solution could not bear any disturbance which might lead to its failure in practice. To improve the situation, two innovative concepts named Bottleneck Capacity Release Ratio (BCRR) and Bottleneck Capacity Release Interval (BCRI) were proposed, and the influence of bottleneck utilization on job shop scheduling under disturbance was studied. Firstly, on the basis of bottleneck identification, series of BCRR were determined by rank. Secondly, bottleneck capacity was used orderly according to the serial BCRR. By using Genetic Algorithm (GA) and plant-simulation platform, initial optimal scheduling solutions were obtained under different BCRR conditions. Thirdly, simulation environment was modified to simulate real production process in which random disturbances including equipment failure, buffer adjustment, process route change and demand time shift were added. The obtained optimal scheduling solution of each BCRR was inputted to simulate again and then each BCRRs optimal solution was obtained. Finally, influence of bottleneck utilization on job shop scheduling under disturbance environment was compared and analyzed. Simulation results demonstrated that robustness and execution performance of job shop scheduling at 100% BCRR were worse than that of non 100% BCRR. When bottleneck was not exploited fully, there existed optimal BCRR and BCRI. However, if BCRR was outside the range of this optimal BCRI, there existed more or less protective capacity of bottleneck resulting in a certain negative impact on the scheduling.

Key words: theory of constraints, bottleneck capacity release ratio, bottleneck capacity release interval, job shop scheduling problem, robustness, random disturbance