Multi-Car Elevator Group Control: Schedule Completion Time Optimization Algorithm with Synchronized Schedule Direction and Service Zone Coverage Oriented Parking Strategies

Multi-car elevator systems consist of shafts with two or more independent cars operating in them. Due to their special characteristics, such as the need to avoid the interference among cars in the same shaft, conventional control methods cannot be implemented on them. Therefore it is necessary to develop group control methods for multi-car elevator systems able to perform an optimal floor call allocation while considering their special characteristics. In this paper we propose a group control method for multi-car elevator systems consisting of a schedule completion time optimization algorithm, an interference risk prevention strategy using the idea of synchronized schedule direction, and parking strategies to assure the coverage of service zones according to the identified passenger traffic pattern. In order to test its performance the proposed algorithm was compared with a sample zoning algorithm in the presence of different passenger traffic patterns. According to the simulation results the performance of our algorithm excels the performance of the sample zoning algorithm in the inter-floor and down-peak traffic patterns. In the case of the up-peak traffic pattern, for which the sample zoning algorithm presents its best performance, the proposed algorithm shows a better result under the arrival rate of 90 passengers/min.