A mathematical programming model for multi-product vehicle routing problem with fuzzy time window and fuzzy demand (Case study: ghofliran company)

In this research, a real and practical problem of the distribution system of a car parts manufacturer is modeled. Qafliran Company, which is one of the leading manufacturers in the field of parts manufacturing for automakers and retail market, has produced various products and tries to get the highest customer satisfaction in timely delivery at the lowest cost in its distribution system. In this research, a model of vehicle routing is presented in which the time window and the multi-product demand of customers are considered in fuzzy mode. Each customer has a trapezoidal time window to receive orders in which customer satisfaction is at best 1 and decreases before and after of expected time of the customer. The objective function is to minimize the distance traveled by vehicles and maximize customer satisfaction. The proposed model was solved by GAMS software and the results showed a very good improvement compared to the current company performance.