Research On Dynamic Parking Allocation Strategy Of Automated Garages Based On Clustering Analysis Of Time Characteristics

With the continuous development of our social economy,the number of vehicles in the city is growing rapidly,and the difficulty of parking in the city is becoming more and more serious.Automatic stereoscopic garages can effectively improve the efficiency of access vehicle and urban land utilization,alleviate urban traffic problems.Plane mobile stereoscopic garage has been widely used for its high degree of automation and large capacity.The research on the parking allocation strategy of the stereoscopic garage is helpful to improve the overall operation efficiency of the stereoscopic garage.The parking allocation process is carried out after the completion of the garage layout,access equipment,storage strategy and parking number.In the process of vehicle access,the parking allocation strategy mainly affects the service time of equipment storage in the stereoscopic garage and the customer waiting time in the process of access the vehicle.The design of reasonable parking allocation strategy can shorten the service time and customer waiting time.Based on the analysis of domestic and foreign scholars’ research on parking allocation strategies,this thesis mainly conduct a study from the following aspects:(1)According to the plane mobile stereoscopic garages entity,and establishes the operating model of stereoscopic garage based on topological grid method.Through the process analysis of stereoscopic garage access vehicle,determine the operation state conversion of stereoscopic garage access vehicle equipment,according to the target location of the access vehicle,storage station(I/O)position and Rail Guide Vehicle(RGV)initial position relationship determine 6 kinds of the vehicle storage tasks and 4 kinds of the vehicle retrieval tasks.according to the average customer waiting time,the operation mathematical model of the stereoscopic garage was established as the evaluation index of equipment operation energy consumption and operation service time.(2)Based on the data of a commercial stereoscopic garage in Xi ’an,the distribution characteristics of the arrival and parking time of customers’ vehicles were studied.The discrete distribution model was used to fit the arrival time of customers’ access vehicles in the stereoscopic garage,the continuous distribution model was used to fit the parking time in the garage,and the non-parametric test analysis method was used to verify and analyze the multi-period data,so as to accurately describe the distribution characteristics of the arrival time of customers’ access vehicles and parking time in the garage at different periods.The verification results show that the arrival time of the customer access vehicle obeys the poisson distribution and the parking time in the garage obeys the gamma distribution.By comparing the simulated arrival process with the actual operation arrival process,it is proved that the arrival process of the customer access vehicle in the stereoscopic garage is poisson process.(3)According to the arrival time characteristics of customers’ access vehicles in the stereoscopic garage and the parking time characteristics in the garage,the influence of the arrival time and parking time of customers’ access vehicles in the stereoscopic garage on the scheduling strategy design was determined.k-means clustering method was used to division the vehicles according to the arrival frequency of access vehicles in different periods.Based on the inference results of vehicle arrival-parking time division and the relationship between I/O to the total service time of the equipment to be stored and the length of parking time,a mathematical model of parking space partition allocation was established to simulate and compare the efficiency indexes of nearby allocation with that designed in this thesis based on the clustering reasoning of vehicle arrival-parking time.The simulation results show that the partition allocation strategy designed in this thesis can effectively shorten the waiting time of customers and reduce the energy consumption of equipment operation.(4)Based on the partitioning of parking space,the influence of RGV path conflict on parking space allocation during dynamic access vehicle operation was analyzed.The random forest prediction algorithm was used to predict the parking time of vehicles in the stereoscopic garage,determine the arrival time of access vehicles,analyze the RGV running time nodes of the access process in each period,and design a dynamic parking allocation strategy to avoid path conflicts by constantly adjusting the RGV running path from the I/O port to the target parking space.The results show that the efficiency index of dynamic parking allocation designed in this thesis is better than that of nearby allocation based on vehicle arrival-parking time clustering reasoning,which proves the effectiveness of the dynamic parking allocation strategy designed in this thesis.The research results provide decision support for the parking allocation process of this kind of stereoscopic garage.