Assessment of an active industrial exoskeleton to aid dynamic lifting and lowering manual handling tasks

Abstract

The aim of this study was to evaluate the effect of an industrial exoskeleton on muscle activity, perceived musculoskeletal effort, measured and perceived contact pressure at the trunk, thighs and shoulders, and subjective usability for simple sagittal plane lifting and lowering conditions. Twelve male participants lifted and lowered a box of 7.5 kg and 15 kg, respectively, from mid-shin height to waist height, five times, both with and without the exoskeleton. The device significantly reduced muscle activity of the Erector Spinae (12%-15%) and Biceps Femoris (5%). Ratings of perceived musculoskeletal effort in the trunk region were significantly less with the device (9.5%-11.4%). The measured contact pressure was highest on the trunk (91.7 kPa-93.8 kPa) and least on shoulders (47.6 kPa-51.7 kPa), whereas pressure was perceived highest on the thighs (35-44% of Max LPP). Six of the users rated the device usability as acceptable. The exoskeleton reduced musculoskeletal loading on the lower back and assisted with hip extensor torque during lifting and lowering. Contact pressures fell below the Pain Pressure Threshold. Perceived pressure was not exceptionally high, but sufficiently high to cause discomfort if used for long durations.

Rationale, Implementation and Evaluation of Assistive Strategies for an Active Back-Support Exoskeleton

“…Also, this study was not designed to observe the effect of the exoskeleton on joints other than the lower back that may be affected, such as the knee. Evidence excluding extra loading on the knee using this device was presented in Huysamen et al (2018).…”

Towards Design Guidelines for Physical Interfaces on Industrial Exoskeletons: Overview on Evaluation Metrics

“…Static (donning and doffing) and dynamic tests are run. In [4] and [5] wearing comfort is assessed through pressure acquisition at the interfaces with the body. To record pressures, in [4], a custom sensing system is used at every attachment point.…”

“…To record pressures, in [4], a custom sensing system is used at every attachment point. In [5], an external commercial pressure mat is used. [6] presents a viable methodology to acquire crucial information on mutual influence of kinematic constraints, reaction forces, attachment pressure and subjective exoskeleton performances.…”

“…Usability index quantifies how the system is natural and easy to use. Perceived ease to don and doff the attachments can be evaluated with the System Usability Scale [5]. Since industrial exoskeletons should improve ergonomics of different working tasks, it is central that these devices do not hinder workers in their routine.…”

Design, Produce and Control of a 2-Dof Upper Limb Exoskeletal Robot

“…Ghobj et al [6] designed 4-DOF pneumatically actuated upper limb exoskeleton suit which is able to carry 8 kgs. Huysamen et al [7] designed an exoskeleton to provide mechanical assistance to the body during lifting and lowering tasks to reduce body loading, back muscle activity and contact pressure. The system includes servo mechanisms and haptic devices.…”