Matheuristics for a VRPTW with competence constraints

International audienceThis paper considers a variant of the multiple depot Vehicle Routing Problem with Time Windows where skill constraints define the places that vehicles can visit. A difficulty faced here is that the special set of instances are highly constrained, due to tight skill and time window constraints. This induced a matheuristic approach, combining advantages of MIP exact approaches with constructive and local search heuristics. A first work furnishes matheuristics based on compact MIP formulation works. Then, a column generation scheme is developed, using previous work to solve subproblems generating aggressively multiple columns. The resulting column generation heuristic outperforms significantly the previous matheuristics