Nonlinear H/sub /spl infin// optimal PID control of autonomous underwater vehicles

Design of a PID control based on the nonlinear H/sub /spl infin// optimal control technique for autonomous underwater robots (AUVs) is presented. First of all, by reparameterizing the conventional PID control in terms of the reference error feedback (REF), the PID control is tuned using the single parameter called the REF gain on account of the nonlinear L/sub 2/-gain analysis. One of the biggest differences arising in the control of such an AUV lies in the slow control and measurement frequency with significant measurement corruption and severe thruster saturation and it is quite difficult to tune the PID control gains. The numerical simulations employing the AUV, called the ODIN, will verify that the proposed control is also effective in such a situation.