Smart Flexible Wrist Exoskeleton with Twisted String Actuators and IMU Feedback

As technology advances, there is a growing demand for lightweight and cost-effective rehabilitation and wearable devices. Traditional metal and pneumatic actuators are increasingly unable to meet modern requirements due to their bulk and high cost. In contrast, twisted string actuators (TSAs) present an ideal solution, offering high efficiency, low cost, and ease of fabrication. In this study, a smart, flexible wrist exoskeleton powered by TSAs was designed and fabricated. By analyzing the relationship between TSA output force, motor rotations, and motor voltage, we achieved precise control of the wrist’s three degrees of freedom. The exoskeleton supports a range of motion including wrist flexion and extension (122°), adduction and abduction (61°), and pronation or supination (86°). Additionally, two nine-axis Inertial Measurement Units (IMUs) were employed to acquire real-time wrist orientation data, which was visualized using UPBGE software, enhancing the device's interactivity. Experimental results demonstrate that the TSA-driven smart flexible wrist exoskeleton excels in portability, cost-effectiveness, and adaptability, making it suitable for a wide range of applications.