Research Of The Vehicle Routing Problem For Coal Mine's Materials Distribution With Service Priorities

With the developing of technology, by reducing material consumption to win profits (the first source of profit), and by reducing labor cost and increasing labor productivity to increase profits (the second source of profit), the potential has been getting smaller and smaller, the lower logistics cost have been widely regarded as the third source of profit for enterprises. Among the total logistics costs, the transportation cost accounts for a quite large proportion. Distribution which is a kind branch transport and the last link in the supply chain, has responsible for deliverying goods to the users with kinds of demands. Whether the design of delivery routes is rational or not, it can directly refluences whether the enterprises delivers goods to customer sites with minimum cost, in time, right quantity and high quality.The topic of this article is from the project with the title "the supply logistics systems engineering research for Zheng Coal Company" Which is cooperated by schools and enterprises. Under this specific application background, the distribution of different kinds of materials in coal mine analyzed has some characteristics:the material demands for different customers exists the different urgency, and vehicles are allowed to run more than one times; dangerous materials are allowed to adopt the joint distribution, that means a customer' needs can be met by a car running more times, or by different vehicles visiting it; the joint distribution of common goods is not allowed, a vehicle is allowed to visit only one customer point per trip, which must be loaded. On the basis of reading lots of literatures, we find that this research has some similarities to three types of problems the vehicle routing problem with time windows, the vehicle routing problem with fuzzy time windows, and the vehicle routing problem with the split demands. By the comparison. the time window in the first two issues can not describe the urgency of needs in this paper's study, because clients receiving services does not specify the time interval segment, and also no one clear expected time window limit, we suggest that "priority of service" characterized the natural number is used to describe the to urgency of the customers' material needs. The characteristic that dangerous materials may be distributed more times makes the optimization can be carried out through learning from the research methods the vehicle routing problem with spilit demands.After determining the boundary of the problem, respectively establish the corresponding mathematical models according to different distribution characteristics of dangerous materials and common materials, and design the improved sweeping algorithm and the improved genetic algorithm to solve the joint distribution model characterized multiple times of dangerous materials. Take an example for the distribution of dangerous materials for Zhengzhou Coal and Electricity materials supplying and marketing limited company, by solving the optimal distribution path results, through some indicators such as the distribution costs, delivery mileage, the number of vehicles used, vehicles's loading rate, the average computing time and the degree of ensuring service priorities analyzes the optimal performance of two above algorithms, and that indicates that under the case of the same number of vehicles used and vehicles'loading rate, the improved genetic algorithm is superior to the improved scanning algorithm, yet sacrifices a longer average time, and also destroy the priority of service to a certain extent, but the improved sweeping algorithm can ensure the priority of service at a greater degree. And compared with the actual distribution situation of the company, further verify the validity of optimization algorithms in the paper. A simple algorithm is designed to optimize the distribution of common materials characterized multiple times and single point. By comparing and analyzing the optimal results with the actual distribution, it shows that the optimization algorithm greatly reduces the cost of delivery and shorten the delivery time.Finally, realize the visualization of the algorithm based on the GUI platform in MATLAB. The user inputs parameters related to requirements and vehicles in the input interface, and can see the optimal results of algorithms in the output interface, to aid decision-making.