Bioinspired Ultrafast Underwater Grippers

Waterwheel plant Aldrovanda vesiculosa is found to achieve trap closure in 20–100 ms underwater, which is ten times faster than that of the terrestrial plant Venus flytrap. Although a lot of bioinspired underwater grippers have been developed for rapid actuation, these devices are still limited by their closure responses (typically > 180 ms), which is considerably slower than that of the aquatic plant. Herein we proposed and demonstrated a new mechanism for Aldrovanda’s rapid closure through morphological observation, theoretical modeling, and numerical simulation. Inspired by this mechanism, we presented a centimeter-scale biomimetic underwater gripper, which achieves fast underwater closure in 70 ms—approaching the plant’s natural speed. A buckling dynamics model was additionally proposed for the high-precision prediction and control of the gripper’s core actuation. This new design principle would contribute to developing high-performance rapid underwater actuation systems.