From Manual Operation to Collaborative Robot Assembly: An Integrated Model of Productivity and Ergonomic Performance

Manufacturing systems involve machines and people. Both productivity and ergonomic performance are of significant importance in manufacturing. However, there is no integrated model to analyze them simultaneously. To bridge this gap, a unified model is introduced to evaluate the productivity and ergonomic performance of both manual operations and collaborative robot assembly systems. Specifically, flow time is used to represent productivity measurement and strain index characterizes ergonomic performance. Models and solutions of both performance measures in manual operations and collaborative assembly processes are introduced. Then a unified model to integrate both metrics, throughput rate per unit of work effort time, is proposed. Finally, a cylinder head assembly example is introduced to illustrate the applicability of the model.