An improved bounded real lemma for H∞ robust heading control of unmanned surface vehicle

Abstract

Aiming at a mass variation of unmanned surface vehicle and the poor or even unmeasurable signal of yaw rate signal, the dynamic output feedback [Formula: see text] control method is proposed for heading regulation based on improved bounded real lemma to reduce the conservativeness and guarantee the robustness. First, a linear-varying-parameter heading error model with external disturbances is established by the consideration of mass as a variable parameter. Second, the dynamic output feedback controller with [Formula: see text] performance is presented for the linear-varying-parameter heading error model, and its nonlinear matrix inequality conditions for the stability of the closed-loop system are deduced from improved bounded real lemma by parameter-dependent Lyapunov to maintain the system robustness. Furthermore, the solution of nonlinear matrix inequality conditions relies on the variable substitution method, and improved bounded real lemma reduces the conservativeness of the controller design by introducing auxiliary relaxation variables to derive the equivalent linear matrix inequality condition. Finally, the heading control simulations for unmanned surface vehicle indicate that the dynamic output feedback [Formula: see text] method based on improved bounded real lemma (IDOF) is robust to system parameter variations and external disturbances, and can effectively reduce the conservativeness of the controller design. Moreover, dynamic output feedback H∞ method based on improved bounded real lemma has faster transient processes and smaller steady-state errors.