Low Energy Buoyancy Actuator for Vertical Underwater Motion
Abstract
This thesis presents the physical and technical premise for implementing and designing anunderwater vehicle capable of moving vertically using the unit s own buoyancy force, andhow this principle benefit in energy efficiency. The goal is to create a prototype unit thatmakes experimental testing and documentation of this principle possible.
An electrical linear actuator with a piston was used to manipulate the unit s volume. Depthcontrol was achieved using a PID controller combined with a pressure sensor, and the controlparameters tuned by implementing simulations of the unit s dynamical behavior. Bycombining two power saving methods, it was estimated (using simulations) to reduce thepower consumption to 12.6% of maximum power consumption. A 3D model of the unitwas made to determine the vertical stability, mass properties, and to create drawings of aprototype.
A functional prototype was successfully implemented, and two physical experiments werecarried out. The physical experiments were not sufficient to determine the unit s energyefficiency using buoyancy as a principle of vertical movement underwater. But the workhere suggest there is a promising potential for the unit being energy efficient.