Minimising workers’ workload in partially automated assembly lines with human-robot collaboration

The benefits of automation in human-operated assembly lines are well known. Despite the rapid progress made in the field, complete automation is not always possible. Often robots cannot replace workers' flexibility, and sometimes there is no economically viable option for automation. A combined production system with both manual and automated parts could be the best configuration in such circumstances. Even with partial automation the number of workers in the line could be decreased, and workers' safety and health conditions could be dramatically improved. In this paper, MILP models are suggested to compare the total workload of workers when different numbers of robots are applied in an assembly line with partial automation and the minimum possible number of workers. The proposed MILP model is implemented in the AIMMS modelling environment and solved using CPLEX. The presented models can help evaluate the impact of adding robots to the line on total workers' workload and may assist decision makers in finding the best possible line configuration.