Abstract
This paper deals with an experimental comparison be‐ tween the proportional integral derivative (PID) control law and the adaptive nonlinear state feedback control, both applied on the AC-ROV underwater vehicle. The experi‐ mental results evaluate the closed-loop behaviour of the system under each controller in various operating condi‐ tions in order to compare how robust they are towards parameters' change and how they can reject external disturbances. It was concluded that the adaptive controller ensures a faster convergence and can adapt to a change of parameters as well as compensate for external disturban‐ ces. The PID needs to be retuned for every parameter change and is more sensitive to external disturbances.