CONTROLLED AND IN-SITU EVALUATION OF INDUSTRIAL EXOSKELETONS: PRELIMINARY RESULTS.

INTRODUCTION: Despite the revolution towards industry 4.0, workers are still exposed to factors that increase their risk of injury and, more specifically, musculoskeletal disorders. Exoskeletons aim to support the worker and reduce musculoskeletal stress. While multiple industrial exoskeletons reached the market and multiple exoskeletons have been tested in laboratory conditions, no in-situ comparison between exoskeletons has yet been published. In this study we aimed to evaluate two industrial exoskeletons, the Laevo and the BackX exoskeletons, supporting the lower back and hip in both a controlled and in-situ environment. METHODS: Twelve industrial workers completed a test in which the physical work was evaluated without exoskeleton. Subsequently, the test was repeated with two different exoskeleton devices. Each test consisted of two parts; part 1 in which isolated movements (e.g. squat) were performed, and part 2 in which the normal working routine was executed. During each trial heart rate was recorded, as well as electro-myographic (EMG) data of the right lumbar erector spinae, quadriceps vastus medialis, biceps femoris and trapezius pars descendens muscle. Session rate of perceived exertion (sRPE) scores were gathered after each set of isolated movements and after the insitu testing. Furthermore, questionnaires regarding the devices usability, workload and heat were gathered. The non-parametric Friedman test was used to compare between different testing trials. RESULTS: Seven subjects who work in an industrial environment (Age: 34.8 years (SD 5.1), 82.4 kg (SD = 14.2)) particpated in this study. Heart rates during isolated movements did not change when using an exoskeleton and no differences were found between both types of exoskeleton (p > 0.417). No differences in erector spinae muscle activity were found between all three testing trials (p > 0.882). Session rate of perceived exertion data revealed a trend to a reduced perceived exertion during squatting with one exoskeleton in comparison to other the testing conditions (p = 0.073). During movements in which the hip joint was more stationary, e. g. overhead lifting, sRPE scores were higher during the exoskeleton trials compared to the non exoskeleton testing condition (p = 0.007). CONCLUSION: Exoskeletons reduce the perceived exertion while performing the specific movements it was designed for, i. e. movements which involve hip flexion. A higher effort was perceived while wearing the exoskeletons during overhead working. Muscle activity and heart rate were not influenced by the industrial exoskeletons. These preliminary results only suggest improvements in perceived exertion during moves in which hip flexion is involved. The reverse effect has been shown when performing a overhead lifting task. When the data of the remaining subjects is processed, and more powerful statistical analysis can be performed, we expect to provide a more refined exoskeleton evaluation.