This paper investigates the benefits of applying simple PID+nonlinear controller to subsea robot. This control structure has the advantage of only adding a supplementary nonlinear feedback loop to the existing linear PID-regulator and at the same time improving both the transient and stability margins. Several simulations and experiments have been performed on the experimental subsea robot (VORTEX) and have demonstrated the improvements of the PID+nonlinear controller over the simple PID. >
['Michel Perrier', 'Vincent Rigaud', 'C.C. de Wit', 'Ralf Bachmayer']
Performance oriented robust nonlinear control for subsea robots: experimental validation