Muscle Strength Assistance of a Shape Memory Alloy Exoskeleton During Lifting and Lowering Tasks

This study developed a wearable exoskeleton using shape memory alloy (SMA) to prevent musculoskeletal disorders and enhance work efficiency. The exoskeleton leverages the shape recovery properties of SMA, activated by temperature changes, to reduce muscle exertion. Thirty healthy male participants were recruited to perform lifting and lowering tasks using weights of 0, 15, and 30 kg in three different postures: stoop, semi-squat, and squat. Electromyography was used to quantify the activity of the thoracic erector spinae (TES) and lumbar erector spinae (LES) muscles, analyzing the muscle support provided by the exoskeleton. Results showed significant reductions in TES and LES muscle activities across all conditions when the exoskeleton was used. Muscle activity increased when larger weights were used, but the exoskeleton's support was more pronounced at larger weights. The SMA-based exoskeleton is energy-efficient, lightweight, and does not restrict movement. This study concludes that the exoskeleton effectively reduces worker fatigue and helps prevent musculoskeletal disorders. However, additional research is needed to assess its applicability in industrial settings, as the experiments were conducted in controlled environments. Future studies will explore the long-term durability of SMA and develop customized designs for various work environments.