A Wearable Scissored-Pair Control Moment Gyroscopes Utilized for Reactionless Support in Human Locomotion

Wearable assistive devices (WADs) show potential for future applications in industrial and medical fields. However, wearing discomfort, caused by factors such as additional weight penalties, inappropriate straps, and joint misalignment, may disrupt the natural balance of human motion, leading to increased metabolic expenditure, muscle fatigue, and even physical injury. These challenges severely restrict the practical application of WADs. To address these challenges, we have developed a reactionless, lightweight WAD that utilizes a single device attached to the shoe, eliminating the need for additional rigid links or straps on the shank or thigh. This design provides assistive torque directly to the target limbs during human locomotion. The proposed device weighs 0.67 kg and can provide an assistive torque of 12 N·m and mechanical power of 10 W. Furthermore, we introduced a human-in-the-loop multiobjective optimization approach considering the assistance effectiveness, power consumption, system size, service safety, and actuator constraints to achieve relative optimality in performance of the proposed device. Cardiopulmonary exercise test and surface electromyography test results from seven participants indicated that the device can reduce the average gross metabolic rate by 12.62%, and the muscle activation of the rectus femoris and soleus by 35.12% and 4.10%, respectively.