The Shortest Path Planning Using A-star Algorithm in RGV Based OHT Dispatching System

Abstract

Overhead hoist transport (OHT) has been widely applied in industry, especially in semiconductor manufacturing processes. The most important issue in the OHT control system is how to determine the shortest path for each transportation task. This paper presents an optimal path planning based on minimization of travelling distance of arbitrary starting location and destination in a specific layout for a workhouse. The A-star algorithm is utilized to solve the problem in the paper, and an example of two rail guided vehicles of OHT system with a routing layout of plural encircle loops under specific operation conditions are examined.