How to provide work instructions to reduce the workers’ physical and mental workload

The transition to Industry 5.0 emphasizes the human-centric perspective and pushes for ergonomic risks prevention and mitigation. The diffusion of the production paradigms of mass customization and mass personalization also increases the need for methods and tools to support workers in manufacturing activities. The growing number of product variants requires a higher cognitive load and increases the likelihood of human errors. Work instructions become fundamental, as well as their digitalization. The technologies enabling industry 4.0 have opened up new scenarios for the use of this information, from extended reality to digital assistance systems. This work deals with the human-centered redesign of a workstation for the wire harness assembly with the aim of mitigating the ergonomic risks for operators, both physical and cognitive. Four different scenarios for using the work instructions were implemented and tested: paper-based instructions, workstation display, mixed reality application usable with a head-mounted display, and augmented reality application that only requires a projection system. The experimentation involved user experience evaluation, performance assessment, and objective postural analysis through inertial sensors.