The Aquaculture Service Vessel Routing Problem with Time Dependent Travel Times and Synchronization Constraints

Abstract

This paper studies the Aquaculture Service Vessel Routing Problem (ASVRP), which is an important planning problem arising in sea-based fish farming. In the ASVRP, there is a set of fish farms located in the sea, where each fish farm has one or more service tasks to be performed by a given heterogeneous fleet of service vessels with different capabilities. Some service tasks require simultaneous operation of more than one vessel and might also have time windows and precedence requirements. Furthermore, varying weather conditions make the sailing times and the service times of the tasks time dependent. The objective of the ASVRP is to maximize the value of the service tasks performed within a given planning horizon. We propose a time discrete optimization model for the ASVRP, formulated as a time dependent, prize collecting vehicle routing problem with synchronization constraints and time windows. Furthermore, we present an Adaptive Large Neighborhood Search (ALNS) heuristic for solving the problem. Results on a number of test instances based on real world data show that both the ALNS heuristic and a commercial solver are able to find high quality solutions for small problem instances, while the ALNS heuristic is superior when the problem size increases.