Research On Scheduling Strategy And Method In Automated Material Handling Systems

With the coming of information age, display industry got rapid development, especially in TFT-LCD region (Thin film transistor-liquid crystal display), but compare with the great investment for a new plant, how to improve the volume of the present line become a hot research direction. TFT-LCD manufacturing is a full automatic system, as the bridge of process to process, AMHS (Automated Material Handling Systems) affects the performance and efficiency of the manufacturing system directly, and among the impact factors of AMHS, scheduling strategy is the most important, so the study of this problem mean more promotion of the production capacity. But since TFT-LCD AMHS is a very big and complex system, we just take AGV for example.This thesis use MOP (Multiple Objectives Programming) and simulation method to study the AGV scheduling strategy, in the hope of finding a way to make the AMHS more benefit to the manufacturing system. The research had been done as follows:(1) Analyzes the performance of AMHS in TFT-LCD area, and molding an AGV bay to study the scheduling strategy and method of AMHS in TFT-LCD industry.(2) Established an electronic map and apply the Dijkstra strategy to search the shortest AGV path.(3) Taking the minimum of process equipment idle time and the shortest transfer time as the optimization goal, molding the multi-objective scheduling system.4) Simulated the multi-objective scheduling strategy (MOSS) model with Flexsim, and compared with the traditional FEFS method, to verify the effectiveness of MOSS.This thesis focus on the AMHS scheduling strategy and scheduling method in TFT-LCD industry, put forward to take the minimum equipment idle time and shortest transfer time as the optimization goal, established MOSS model and verified the MOSS is effective.