Submersible Soft-Robotic Platform For Noise-Free Hovering Utilizing Liquid-Vapor Phase Transition

Hovering at any depth, is one of the most important requirements for underwater robotics, which calls for large-range buoyancy control ability. Although various underwater robotics have been proposed and developed, the requirements of noise-free, environmental tolerance, and low energy consumption in hovering manipulation, are still attracting a lot of attention for underwater tasks. Herein, a submersible soft-robotic platform driven by the self-contained liquid-vapor phase transition is developed. The proposed soft-robotic platform precisely modulates its buoyancy, showing an excellent positioning ability underwater. The proposed soft-robotic platform performs reversible rise-and-sink motions underwater, and generate a buoyancy force of 0.93N (131% of its weight) with an accuracy of +/- 2.5mN, at a heating temperature of 63 degrees C. It shows that more than 40% of the total buoyancy change is achieved within 55s, and the platform hovers in any depth in a range of 450mm (limited by the adopted water container) in 18s, with positioning fluctuation of 17.42mm. This soft-robotic platform demonstrates active vertical motions in water and suggests a feasible approach to develop noisy-free and high-reliability underwater robots, which guide the further design of autonomous underwater vehicles (AUVs).