# A Smart Rehabilitation Glove Based on Shape-Memory Alloys for Stroke Recovery
## 4 Results and Discussion
### Periodic Rehabilitation Training  
To assess the feasibility of the amplifier structure, we sequentially used wires of different lengths on the structure for experimentation, as shown in Figure 7. The total length of the structure was 16 cm, corresponding to a single-fold wire length of 16 cm. By changing the number of winding turns, we achieved N-fold amplification, namely wires of 32 cm, 48 cm, 64 cm, 80 cm, and 96 cm. The displacement of the SMA wires at different amplification factors was measured using a scale, and it was found that the displacement was approximately proportional to the length, with a strain of around 5%. These results confirm the feasibility of the amplifier structure. The wearing effect is shown in Figure 8a. To make the rehabilitation glove more portable, we use a small power-supply module (as shown in Figure 8b). The module has dimensions of 6 cm \(\times\) 8 cm \(\times\) 5 cm and consists of a switch button, a voltage adjustment button, a battery, and other components. By simply switching the voltage-adjustment button or using the mobile application, different voltage levels (0-12 V) can be supplied, enabling rehabilitation training modes of different intensities. For the authenticity and effectiveness of the experiment, we used a silicone prosthetic hand model instead of a human hand for the rehabilitation training test. As shown in Figure 8c, the silicone prosthetic hand model was sequentially fitted with the rehabilitation glove, connected to the power-supply module, and paired with the mobile app via wireless transmission. First, we selected the low-intensity mode and pressed the start button. Then, the SMA wires embedded in the glove were heated up and began to contract. As the temperature increased, the contraction increased, and the fingers gradually extended. After 8 s, the middle finger reached the fully extended position. At this point, the current was cut off, and the SMA wires began to cool naturally through the ventilation openings. After 13 s, the glove returned to room temperature, and the fingers returned to their natural state. Similarly, we subsequently conducted rehabilitation training in the medium- and high-intensity modes. The results showed that with increasing intensity, the time required for rehabilitation training was significantly reduced. In the high-intensity mode, it took only 3 s to fully extend the fingers, achieving a finger bending angle change of approximately 34\({}^{\circ}\), which can improve rehabilitation frequency, especially for patients with severe hand-function impairments. Figure 6: (**a**) Switch between different intensity modes. (**b**) Wireless interconnection of rehabilitation glove and mobile terminal. To verify the technological advantages, we quantitatively compared our rehabilitation gloves with traditional electric and pneumatic gloves. Compared with [PERSON] et al. 's motor-driven glove (350 g weight, 40 cm\({}^{3}\) volume) [16], our SMA-based prototype achieves a 50% weight reduction (180 g) and 40% volume shrinkage, primarily due to the amplifier structure that compresses the SMA wires from 680 mm to 160 mm. In contrast to [PERSON] et al. 's pneumatic glove, which requires 10 s for finger flexion and has a power density of 9 W/kg [17], our design demonstrates a 30% improvement in response time (7 s for 50 mm contraction) and 33% higher power density (12 W/kg). The mobile-app-integrated system further enables dynamic mode-switching, a feature absent in traditional fixed-training devices (e.g., [PERSON] et al.) [6]. The development of more targeted and flexible training modes tailored to diverse patient needs remains at an early research stage. Future work will focus on creating freely adjustable modes (beyond existing preset options) to enable personalized therapy based on individual conditions and medical supervision.