Preliminary Studies on a Variant of TSP for Servicing Printers and Copiers

We analyze a case study and we model it as a variant of the Traveling Salesman Problem. It is characterized by multiple time windows, variable service duration, priority constraints, and appointments with customers. The definition of the feasible region differs from the classical one: a maximum duration is imposed to the tour, and some customers may be neglected. The number of customers to visit is fixed as the maximum number given all constraints: it is found by solving a further optimization problem. The objective function to minimize is the sum of the time required to serve this number of customers. We propose a mathematical formulation for this problem and we solve it on two real instances. We compare the solutions obtained with the ones implemented by the firm.