Usability of back support, shoulder support and sit-stand passive occupational exoskeletons: A heuristic evaluation of the designs

Occupational exoskeletons promise to alleviate musculoskeletal injuries among industrial workers. Knowledge of the usability of the exoskeleton designs with respect to the user device interaction points, and the problems in design features, functions and parts, evaluated and rated using design principles is still limited. Further, the usability of exoskeletons when assembling, donning, doffing and disassembling them, tasks that can be considered pre and post use tasks are also critical to evaluate, especially from a device design standpoint. We conducted a heuristic evaluation of the usability of three popular exoskeletons, a back support device, a shoulder support device, and a sit stand exoskeleton when assembling, donning, doffing and disassembling them. Seven evaluators used Nielsen and Shneiderman usability heuristics to evaluate the devices. Results indicate that none of the three exoskeletons had any catastrophic usability problems, but all three had major usability problems including accommodating diverse users, the assembly, donning and doffing being a two person operation, poor documentation, a lack of sequence indicators during assembly of the devices, presence of safety hazards while donning and doffing the devices, and manual strength requirements. Further, the assembly task is the most difficult task resulting in the most violations of usability heuristics. The exoskeleton human factors research community should include diverse users in their evaluations and conduct usability, accessibility, and safety evaluations of these devices to provide design feedback to device designers.