Research On The Storage-retrieval Strategies Optimization And Vehicle Scheduling For Non-independent Stereo Garage

In recent years,the automotive industry has a fast development.Owing to the continuous improvement of social economy,the per capita car ownership rises rapidly.At the same time,it brings "parking difficulties" to the cities that have a high cost of land.In order to alleviate the pressure of parking and meet the needs of fast-paced development of modern cities,a great number of stereo garages are built.Especially,the laneway-stow-typed stereo garage is highly favored by people due to its high automation level and large storage capacity.In the thesis,the laneway-stow-typed stereo garage is taken as research objects,and its layout of parking space is required to be non-independent,which is referred to as non-independent stereo garage for short.This kind of garage has a good market prospect due to its advantages of smaller floor area and larger capacity.However,it still suffers from the problem of weak service capability,e.g.,long time consumption and high energy consumption in the process of taking in/out cars.In order to achieve the low energy consumption and high efficiency of a non-independent stereo garage,its storage-retrieval strategies and vehicle scheduling should be optimized.The main researches and innovations of the thesis are as follows:(1)The location model of buffer parking space is built.For a non-independent stereo garage,its stacker sometimes conducts the operation of garage shift in the process of taking in/out cars.The related studies directly replace the entrance and exit of the garage as a buffer location,where a car is temporarily taken out from the garage and then returned to the original parking space.Considering the turnover factors of parking spaces and no increase in the garage cost,a mathematical modeling method is provided to locate the reasonable buffer parking space,based on the single facility location approach that minimizes the distance sum of weighted coefficients.By this means,the time and energy consumption of a stacker is reduced in the garage shift process.(2)The time/energy-consuming model is simulated and analyzed.According to the characteristics of traffic flows in a garage during rush hours and peak hours,the storage-retrieval strategies with buffer parking are discussed based on the simplified model of the non-independent stereo garage.Afterwards,the average time/energy-consuming models of a stacker are proposed under different storage-retrieval strategies.Furthermore,an experimental system of taking in/out cars is developed based on VB program language.By this experimental system,some simulation results are analyzed to explore the impact of three kinds of storage-retrieval strategies on the time and energy consumption of a stacker in the process of taking in/out cars.Moreover,the suitable storage-retrieval strategy is put forward to meet the different requirements of reducing the consumption of energy and time of a stacker at different times.The experimental results show that the garage with buffer parking spaces takes less time and consumes less energy than that without the buffer parking spaces,which further prove the rationality of the location model of the buffer parking space.(3)The vehicle scheduling optimization is proposed based on an improved genetic algorithm.In order to minimize the total access time and obtain the lowest energy consumption,an improved genetic algorithm is put forward to optimize the vehicle scheduling under three storage-retrieval strategies.The experimental results show that the optimal access sequence and path are obtained,and also prove that the algorithm has a good convergence.