Aiming　at　the　nonlinear　characteristics　of　unmanned　surface　vehicle　(USV)　yaw　caused　by　the　impact　of　water　flow,　a　nonlinear　parameter-varying　(NPV)　USV　model　is　established　based　on　yaw　motion,　and　the　NPV　H∞　robust　heading　control　method　is　proposed　to　improve　the　rapidity　and　robustness　of　heading　regulation.　Firstly,　a　nonlinear　Fossen　model　is　established　based　on　the　hydrodynamic　damping　by　the　low　aspect-ratio　wing　theory,　which　can　better　describe　the　characteristics　of　ship　hull　impacted　by　the　flow.　The　dynamics　model　is　simplified　into　a　maneuvering　model　by　ignoring　the　roll　velocity　and　cross-flow　drag,　then　an　NPV　heading　model　is　established　by　introducing　the　heading.　Secondly,　a　Lyapunov　function　related　to　the　state　of　the　heading　control　system　and　parameter-varying　of　the　surge　velocity　is　constructed　to　derive　the　solving　conditions　of　the　nonlinear　controller,　which　satisfies　the　H∞robust　stability　of　the　heading　closed-loop　control　system.　This　condition　is　a　nonlinear　matrix　inequality　(NLMI).　Moreover,　since　the　NLMI　is　difficult　to　solve,　the　nonlinear　matrix　in　the　NLMI　is　replaced　with　the　polynomial　matrix　based　on　the　sums　of　squares　(SOS)　theory　to　transform　into　polynomial　linear　matrix　inequalities,　which　can　be　solved　by　SOSTOOLS.　Finally,　the　results　of　the　simulation　indicate　that　the　NPV　H∞　controller　has　fast　system　response　and　higher　accuracy　for　heading　regulation.　©　2024　Northeast　University.　All　rights　reserved.