Abstract
The goal of this study is to develop a new buoyancy control device for underwater robot utilizing phase transition of material. Conventional underwater robots and submarines adjust buoyancy by discarding a set of iron balls or seawater in other place, which is harmful to the environment. We previously measured the device's buoyancy by strain gages on a beam. But the device has to be hanged by a wire connected to a beam in this method. If a buoyancy measuring system is in the inside of the device, we can obtain information of device's buoyancy in an operation of the device. We manufactured a buoyancy control device and installed two distance sensors in it; a potentiometer and a hall sensor. The volume change mechanism of the device consists of a piston and a syringe. The two sensors measure the moving distance of the piston, and buoyancy can be calculated from the information. Then, we conducted an experiment on controlling the moving distance of piston and confirmed that the device can control its own buoyancy.
