Ionic Wind Cooling Enables High-Frequency Shape Memory Alloy Actuators for Origami-Inspired Soft Robotics

Shape memory alloys (SMAs) are attractive for soft robotic actuation because of their compactness and high power density, yet their widespread application is limited by slow thermal recovery. Here, we introduce ionic wind cooling as a compact thermal-management strategy to overcome this bottleneck and improve the cyclic actuation performance of SMA-driven soft robotic systems. Two ionic wind configurations were designed and comparatively evaluated for localized cooling of SMA springs. Both significantly accelerated SMA recovery with only minimal additional power input, and the needle-ring configuration was selected for subsequent integration because of its favorable stability and compact geometry. By coupling SMA springs with an origami-based compression-twisting mechanism, an actuator-level soft twisting module capable of reversible bidirectional rotation exceeding 80° was developed. The cooling strategy was further extended to multiple SMA-driven modules and a reconfigurable soft robotic arm capable of coordinated twisting, bending, and multimodal grasping. The results show that ionic wind cooling not only enhances the recovery of individual SMA actuators but also enables faster motion switching and improved cyclic response at the system level. This work demonstrates ionic wind cooling as a compact and effective strategy for enhancing the dynamic performance of SMA-driven soft robotic systems.