Simulation Modeling and Ergonomic Assessment of Complex Multiworker Physical Processes

Discrete simulation of complex multiworker physical processes, for ergonomic and/or performance analysis, is still relatively undeveloped. Existing approaches typically have taken either a classical simulation view of the problem (focus on activities, resources, and queues: workers treated as machines) or an analytical ergonomics perspective (detailed human modeling and ergonomic assessment for well-defined limited tasks). This paper presents a new way to tackle such problems, based upon elements of both of these approaches. Novel methods are described for modeling complex multiworker physical processes within a traditional discrete-event simulation environment. These methods result in a high-level language for generating activity-based process models quickly and easily, based upon simplified activity representations. Laboratory experiments are used to derive equations that can then be used to generate ergonomic assessments (i.e., relative injury risks) for the most influential activities. By implementing these equations using data generated from a simulation run, estimates of ergonomic consequences can be obtained. To illustrate the approach, it is applied to the panelized residential housing construction process, where multiple workers build houses by moving and installing large heavy prefabricated wall panels. The example illustrates the steps presented and feasibility of the approach.