A constraint-programming based decomposition method for the Generalised Workforce Scheduling and Routing Problem (GWSRP)

Abstract

Recent studies prove that industry is confronted with workforce issues which are, the majority of the time, determining factors in its evolution over the long-term. The aims of workforce management are to balance numerous objectives including relations between jobs/workers (workers' skills), operational costs, customers' quality of service and workers' quality of service. In their workforce management, many manufacturers include the routing of workers between customers. Another challenging and important difficulty is the coordination between workers to perform a job or a service. This paper deals with the Generalised Workforce Scheduling and Routing Problem (GWSRP) where 9 temporal constraints ensuring visit dependencies are all together taken into account and where customers and workers' quality of service are taken into consideration. A Constraint-Programming based Decomposition Method (CPDM) is proposed, firstly based on a relaxation of coordination constraints, and secondly with a constraint programming approach taking coordination constraints into account. Numerical experiments are achieved on instances derived from WSRP benchmark instances with up to 177 customers and 59 vehicles.