Abstract:To alleviate the problems of parking difficulty in rush hours, long waiting time in queue and low efficiency of stereo vehicles, a stereo garage with efficient parallel storage is designed. First, we make full use of the three-dimensional garage bottom space to design sub-mother vehicle buffer pool storage scheme, and improve the efficiency of vehicle storage and extraction through the buffer pool’s continuous handling work. A mother car is arranged in each layer of the garage, and the multi-layer circular parking space allocation strategy is adopted to realize the parallel storage function of the multi-layer mother car in the garage, and the parallel storage efficiency of the stereo garage is calculated by analyzing the working sequence characteristics of the stereo garage in the case of multiple storage requests. Second, the M/M/n queuing model for vehicle storage is established based on the customer’s vehicle storage process, and the queuing theory is used to analyze the average utilization rate of elevators under different customer arrival rates, and the average queuing time, queue length and the waiting probability for customers under different number of elevators. Finally, a reasonable capacity of the vehicle storage buffer pool is designed based on the actual vehicle parameters, garage structure size, the movement parameters of the sub-mother vehicle handling system, and the occupied area of stereo garage. In addition, the customer vehicle storage indexes before and after the buffer pool are compared to verify the significant reduction in customer waiting time of vehicle storage by the buffer pool. The results show that the stereo garage system increases the storage efficiency by 39% compared with the traditional stacker stereo garage under parallel storage condition of five vehicles. The average queuing time of customers is reduced by 47.8% when the customer vehicle arrival rate is 75 vehicle/h and the capacity of the sub-car buffer pool is set to 4. Therefore, the parallel car storage scheme of the stereo garage with buffer pool can significantly improve the efficiency of car storage and reduce customer waiting time, which can further meet the requirements of customer’s car storage.