SMA-TENG Actuator with Tactile Sensing Capability

Shape memory alloy (SMA) is widely employed in developing actuators. However, the lack of sensing capabilities limits its application. This study presents a sensing-actuation integrated device based on SMA and triboelectric nanogenerator (TENG), achieving tactile sensing while maintaining the actuation performance. The proposed core-shell structure not only repurposes the SMA spring as a key component of actuation and sensing, but also effectively isolates the actuation current to prevent interference with the sensing signal. The aerogel-modified silicone composite layer is applied to the SMA to reduce temperature rise by 30.56%, ensuring the sensing performance. With a rapid response time of less than 31 ms and stable sensing performance exceeding 2000 cycles, the SMA-TENG actuator reliably detects dynamically varying forces and bending. Additionally, it generates a maximum actuation force of 3.21 N, which represents a 12.2% increase compared to a standard SMA spring, due to the pre-stress introduced by the composite layer. Moreover, it can actuate a displacement of 7.7 cm and exhibiting a power density of 7.15 × 10³ W/m³ (at 0.84 V, 6 A). Finally, we validate its haptic sensing capability during actuation, demonstrating its potential towards interactive robotic systems.