Abstract: Aiming at the strong nonlinearities of hydrodynamics, and the influences of wind, wave and current on USVs (Unmanned Surface Vehicles), an H_∞ robust yaw keeping controller based on LPV (Linear Parameter Varying) model is proposed. The LPV model uses the Froude number as the varying parameter, reflects the USV’s nonlinear hydrodynamics along with the Froude number, and simplifies the parameters identification and controller design. By using the Froude number as the scheduled parameter, an H_∞ robust yaw keeping controller is designed on the basis of bounded real lemmas to attenuate the disturbances. Simulations on a 3-DOF underactuated USV simulation platform verify the effectiveness and robustness of the proposed controller.

Key words: unmanned surface vehicle, hydrodynamic modeling, linear parameter varying system, disturbances attenuation, yaw keeping control