A soft robotics lab's Professor Wei Wang, the mechanical engineering department recently developed a new buoyancy control device using soft material. The new soft swim bladder consists of an elastic cover layer, lightweight flexible heating elements, and a polymer-based elastic cover.

Various marine life underwater controls the buoyancy to control its depth. To mimic this function, former buoyancy control devices had to use pistons, motors, and other complex parts. It made the whole system's volume and mass go up and also entailed problems such as vibration and noises. Professor Wei Wang made a new buoyancy control device using volume change in a liquid-vapor phase transition, without any mechanical devices. The soft robotics team made a robot fish using a soft swim bladder, and accomplished more than 10 movements, using electric signals underwater. It can mimic all the movements of real-life fish.

Professor Wei wang also said he believes that the new device can substitute the former soft actuator system, and also be used for underwater exploration devices. The research was funded by the NRF, the National Research Foundation. The research was published in a journal 'Material Horizons' in the name of 'Robotic soft swim bladder using liquid-gas phase transition'.