Submarine H∞ depth control wave disturbances

A procedure for designing H^∞ depth submarine controllers is proposed. The design has been obtained by combining polynomial and state space H^∞ methods. The polynomial approach allows the low and high wave frequency disturbances to be included in the design setting as design ´parameters´. Reformulating the polynomial control design structure in the state space scheme enables the use of standard design software. The numerical problem caused by the ill conditioning of the standard interconnection system, was solved by expressing the system in a ´block observable´ realization. The criterion for selecting the cost weighting functions is defined in terms of the dynamical system structure of the submarine. The success of the design procedure has been evaluated through nonlinear simulations.