Low-Cost Hybrid Underwater Glider Utilizes Buoyancy and Thruster Actuation: Design and Control

This paper presents the design and control method of the hybrid underwater glider (HUG) for hands-on investigative engineering. The HUG is a lightweight, small, modular, and low-cost underwater vehicle. The HUG uses a piston buoyancy system to control buoyancy and pitch angle and two thrusters to control yaw angle. A hybrid control method utilizing both a piston buoyancy system and a pair of horizontal thrusters is proposed. The novelty of this study is: 1) a two-hull design to facilitate modularity and ease of assembly, 2) an effective piston buoyancy and thrusters’ mechanism to reduce the weight and size of the vehicle, and 3) a pitch control method based on equilibrium identification to enables a fixable and convenient parameters selection and reduces model dependence. Experimental results show that the HUG design reduces the thrusters’ disturbance to pitch angle control, and pitch angle control with the hybrid control method has less overshoot compared to the PID controller.