Attitude Control of Underwater Vehicles using Control Moment Gyros

Abstract

This research illustrates the application of angular momentum of gyros in attitude control of underwater robots in consideration of underwater drag. Unlikely those commonly being used as sensors, the gyros show how their capabilities that generate torques as underwater actuators. Recently, actuators using the principle of angular momentum conservation have widely been utilized in attitude control of satellites and spacecrafts. CMGs as an internal torque actuator overcomes several drawbacks other external underwater actuators have. Control Moment Gyros(CMGs) creates large amount of torque compared to other internal actuators due to its mechanical structure. Here we demonstrate the attitude of underwater robot in accordance with Coriolis acceleration and angular momentum conservation. Instead of conventional methods which did not consider hydrodynamic effects into CMG dynamics, this study takes the factors of water drag, hardware saturation and viscosity into account and thus simulated the most feasible motion in fluid. It further analyzes of the controller which is designed to respond stably even with water drag corresponding to numerous underwater parameters and is finally simulated in time response.