A genetic algorithm for designing job rotation schedules considering ergonomic constraints

Job rotation is one method that is sometimes used to reduce exposure to strenuous material handling, however, developing effective rotation schedules can be complex in even moderate size facilities. The purpose of this research is to develop methods of incorporating safety criteria into scheduling algorithms to produce job rotation schedules that reduce the potential for injury. Integer programming and a genetic algorithm were used to construct job rotation schedules. Schedules were comprised of lifting tasks whose potential for causing injury was assessed with the Job Severity Index. Each method was used to design four job rotation schedules that met specified safety criteria in a working environment where the object weight, horizontal distance, and repetition rate varied over time. Each rotation was assigned to a specific gender/lifting capacity group. The advantages and limitations of these approaches in developing administrative controls for the prevention of back injury are discussed.