Prescriptive Maintenance and Routing for a Fleet of Degrading Vehicles

The digitalization of the economy in the past decades has made data availability grow and become more important. Consequently, in the field of maintenance, in recent years, different jargons appeared, among which prescriptive maintenance has gained remarkable popularity. In this prescriptive maintenance study, we introduce the notion of degradation management to one of the most important combinatorial optimization problems, the vehicle routing problem. A fleet of vehicles has a set of points to visit each day. Each of those points has known deadlines. Additionally, vehicles are subjected to degradation and a stochastic state of health evolves with the distance traveled. Finding the best order of points to visit requires the solution method to account for the long-term degradation, since solving for each day independently in the way that most logistic operations are currently done, can lead to suboptimal solutions and increases the risk of downtime. Here, this optimization problem is stated using a Multi-Integer Linear Programming (MILP) formalism.We also provide numerical experiments, solving it and discussing the implications of considering degradation while optimizing the exploitation of vehicles. In conclusion, our solution proposal can reduce breakdown and maintenance costs.

Keywords: Vehicle routing problem, Maintenance, Decision-making, Numerical optimization, Degradation and reliability models.