SRBFOs for Solving the Heterogeneous Fixed Fleet Vehicle Routing Problem.

The purpose of this paper is to present a new method to solve the heterogeneous fixed fleet vehicle routing problem (HFFVRP) based on structure-redesign-based bacterial foraging optimization (SRBFO). The HFFVRP is a special case of the heterogeneous vehicle routing problem (HVRP), in which the number of each type of vehicles is fixed. To deal with this combinatorial optimization problem, two improved SRBFOs (SRBFOLDC and SRBFONDC) are presented by integrating the same time decreasing chemotaxis step size mechanism of BFOLDC and BFONDC into the optimization process of SRBFO. SRBFOLDC and SRBFONDC are successfully applied though encoding the position of bacteria by 2N dimensions. The first N dimensional vectors indicate the corresponding vehicle, and the next N dimensional vectors present the execution order of the corresponding vehicle routing. In the simulation experiments, it is demonstrated that SRBFONDC and SRBFOLDC are efficient to solve the heterogeneous fixed fleet vehicle routing problem with lower transportation cost and get better vehicle routing. Besides, SRBFONDC performs best compared with other five bacterial foraging optimization algorithms.