Analysis of Human-Exoskeleton System Interaction for Ergonomic Design

Objective Lower-limb exoskeleton systems are defined as gait training or walking-assisting devices for spinal cord injury or hemiplegic patients. Crutches, straps, and baffles are designed to protect subjects from falling. However, skin abrasions occur when the interaction forces are too large. In this study, the interaction forces between the human body and an exoskeleton system named the AIDER were measured to confirm whether the design was ergonomic. Background The AIDER system is a wearable lower-limb exoskeleton. It secures a subject by binding on the waist, thighs, shanks, and feet. Method Eight healthy subjects participated in the study. The interaction forces of the waist strap, thigh baffles, shank baffles, and crutch handles were measured by pressure sensors. Ten repetitions were completed in this study. After one repetition, custom comfort questionnaires were completed by the subjects. Results Although a few of the peak values of the maximum intensities of pressure between the hands and crutch handles reached the minimum value of the pain-pressure threshold (PPT), the average pressure intensities were much smaller than the PPT value. Conclusions The results indicated that the mechanical structure and control strategy of the AIDER must be improved to be more ergonomic in the future.