Study of 3 dimension trajectory tracking of underactuated autonomous underwater vehicle

• Tracking problem is divided into a guidance problem and a control problem.
• The dynamic model is utilized as a matrix form rather than decoupled equations.
• We come up with the desired velocity using an error vector.
• Nonlinear parameters of AUVs׳ dynamic model are considered in controller design.

This paper addresses the problem of trajectory tracking control for underactuated autonomous underwater vehicles (AUVs) in 3 dimensions space. Given a smooth, inertial, 3D reference trajectory, in order to make the position error to stay in the neighborhood of zero, the control algorithm uses vehicle׳s kinematic equation and linear system stability theory to compute the desired body-fixed velocities. Using these methods, the velocity error dynamics are obtained. Backstepping techniques are used, forcing the tracking error to an arbitrarily small neighborhood of zero. Simulation of a spiral trajectory is performed. The result shows that the controller can realize 3 dimensions trajectory tracking effectively.