Balancing high operator's workload through a new job rotation approach: Application to an automotive assembly line

Reducing musculoskeletal disorder (MSD) risk factors and work monotony are the main reasons that persuade a manufacturing industry to apply job rotation in the workforce planning. This research aims to smooth the daily workload by designing an optimal sequence of job rotation using a mathematical model. The study consists of two main steps. The first is an ergonomic analysis of the workstations to evaluate the physical workload of different jobs. An in-house risk assessment method was used to identify physical workloads of each job. In the second step, a mathematical model was developed to schedule job rotation and optimize/balance the cumulative workload. Mixed integer programming is proposed to implement a platform for the ergonomic job rotation. The objective of the job rotation programming in this research was to determine the optimal sequence of jobs for each worker such that the global daily workload of the workers would be balanced. The proposed job rotation strategy reduced the dispersion and the deviation of the daily cumulative workload among the workers considering that the rotation only occurred inside the specific groups and not between the groups.