Optimal Control of CP Propeller based on real-time measurements

The aim of this paper is to present the working principle of an automatic speed and pitch controller for CPP. The advantage of this kind of propellers becomes relevant when the ship operates in speed and loading conditions quite different from the designed ones; generally the master acts on fixed pairs of propeller pitch and revolution speed, defined in the design stage. In previous works, the authors considered a rpm and pitch control based on direct torque measurements and an offline optimization process, that generated a surface of optimum working points with respect of Kt/J2 and other parameters. A critique to this method may be that, in this way, the uncertainties on model data affects the optimum working point estimate. In this paper the optimization problem is solved by applying an extremum seeking technique, based on realtime torque shaft (as in the previous work), speed and consumption measurements. Moreover, in order to improve the wake data for the simulated test cases, a series of self-propulsion towing tank tests in different model load condition are carried out.