A Sphere Region Tracking Control Scheme for Underwater Vehicles

The concept of region tracking control has advantages for underwater vehicles for some special missions, such as pipeline tracking. This article develops a sphere region tracking control scheme based on barrier Lyapunov functions, where an observer is used to estimate the effects of external disturbances and modeling uncertainty. It is shown that the distance between the vehicle's position and the corresponding point on the desired trajectory is always kept within the prescribed boundaries. Simultaneously, the absolute value of each attitude-tracking error is less than another defined boundary. Finally, the new control scheme is applied to a fully actuated underwater vehicle, and the advantages of this strategy are validated compared to other region-tracking control schemes.