Multi-period and multi-workday workforce scheduling for manufacturing workstations with multiple workers

This paper discusses the complex workforce scheduling problem where a workday is divided into multiple periods and the planning horizon is extended to cover several workdays, or MPMW-WSP. Additionally, there can be multiple workers at individual manufacturing workstations. The MPMW-WSP focuses on the safe exposure of workers to a given ergonomic hazard that is dominantly present in the workplace. Dominant ergonomic hazard can be either a single-limit hazard or variable-limit hazard. A hybrid solution procedure is employed to solve the problem. It consists of a heuristic method to estimate an initial workforce size and an integer linear programming (ILP) model to determine a minimum number of workers to be rotated among different tasks so that their daily hazard exposures are within the permissible or recommended limit. Numerical examples and computation experiment are also presented.