Nonlinear H-infinity inverse optimal output feedback control for ship course

To attenuate the perturbation of the model parameters and the uncertain observer error introduced by the state observer in the nonlinear optimal control of ship course, we propose a nonlinear inverse H-infinity optimal control algorithm. To achieve the objective of wave filtering, we design the observer based on the passive theory, in which the variance of the wave disturbance is not required, thus reducing the number of parameters. Considering the effect of model parameter perturbation to the observer error, we develop a local (global) H-infinity optimal performance index. Because the local optimization is based on solving the generalized algebra Riccati equation (GARE), the global optimization is transformed to finding the Lyapunov function of the close-loop system by inverse optimal method. Thus, the optimal controller satisfying the two performance indexes is obtained, and the stability is proved. The simulation results show the effectiveness of the proposed algorithm.