Like Ripley’s power loader in the 1986 film Aliens, Korean scientists have unveiled a manual labor exoskeleton they call WeaRo, paving the way for safer robot assisted work.
The 11.5 lb wearable device reportedly reduces stress on human muscles by between 18.2% and 29.0% while in use. The scientists behind the development believe the WeaRo exoskeleton could soon come to hold an essential place in worker safety, citing the high frequency of back injuries among workers today.
Aiding Human Effort
In 1986, Aliens envisioned exoskeletons as an essential future tool for multiplying human effort in manual labor, in contrast to the predominately military use for such technologies presented in other science fiction. This is industrial perspective is shared by the Yonsei University scientists behind the development of WeaRo.
Currently, human augmentation devices are designed to support a single range of movement, limiting their application to specific tasks. Yonsei University scientists aimed to overcome this limitation by developing a system capable of supporting multiple degrees of movement, enabling users to perform varied and complex tasks. Their efforts led to the creation of WeaRo—a soft, wearable robot.
WeaRo assists users in lifting, lowering, and carrying objects, significantly reducing strain on key muscle groups. Tests revealed that the device decreases lumbar strain by 18.2%, biceps strain by 29.1%, and triceps strain by 27.0%. These results are particularly notable given that back injuries, which account for 31.9% of work-related injuries, are the leading cause of workplace injuries.
Moreover, recent research suggests that traditional lifting techniques, such as squatting instead of stooping, offer trade-offs rather than clear benefits. Reducing overall bodily stress is proving to be the most effective strategy for minimizing injury risks.
Designing and Testing the Exoskeleton
After evaluating previous attempts to create wearable robots, the Yonsei team chose Twisted Spring Actuators (TSAs) as the motion-driving mechanism for WeaRo. TSAs struck a balance between active pneumatic systems—often too heavy for comfortable wear—and passive elastic systems, which restricted the user’s range of motion.
The team’s design incorporated a back brace and armbands that worked in tandem, transferring motion through a two-stage sequence: first using the lumbar region and then engaging the arms. This approach relieved bodily stress through active pressure while leveraging gravity as a counterforce. The device’s lifting sequence could also be adjusted for specific use cases, providing flexibility for various tasks.
To test WeaRo, the researchers recruited eight adult males with no history of back pain. The participants were equipped with electromyography (EMG) sensors to measure muscle activity. During initial trials, the team compared a TSA-based system that allowed simultaneous movement against their Adjustable Twisted Spring Actuator (ATSA) system, which supported two-stage motion. The two-stage design proved far more efficient, reducing the required range of motion and overall muscle stress.
Subsequent tests evaluated repetitive stooping and squatting motions, both unassisted and with WeaRo’s support. Participants using WeaRo experienced a significant reduction in muscle stress—ranging from 18.2% to 29.1%. A final set of tests on lighter, continuous tasks showed a stress reduction of 8-17.1%, further demonstrating the device’s versatility.
Looking Ahead: The Future of Exoskeletons
The Yonsei team’s next goal is to integrate artificial intelligence (AI) into WeaRo’s system. Their vision involves AI detecting a wearer’s intended movement through subtle posture cues and providing precise, real-time assistance. Additionally, the team is working on developing robust maintenance procedures to ensure safe and effective long-term use of the device.
With advancements like WeaRo, the potential for wearable robotics to improve workplace safety and productivity continues to grow, paving the way for a future where human augmentation devices are as versatile as the tasks they aim to support.
“The significance of this study lies in developing a comprehensive methodology that encompasses movement analysis, wearable robot design, and effectiveness validation to reduce work-related injuries,” said co-author Dongjun Shin, PhD, of Yonsei University, in the Republic of Korea.
The team has detailed their work in a recent paper, “A Soft Wearable Robot with an Adjustable Twisted String Actuator and a Two-Stage Transmission Mechanism for Manual Handling Tasks,” which appeared on January 08, 2025 in Advanced Intelligent Systems.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.