Global uniform asymptotic stabilization and k-exponential trajectory   tracking of underactuated surface ships with non-diagonal inertia/damping   matrices
  In this work, we investigate the state stabilization and trajectory tracking problems of underactuated surface ships with full state model of having non-diagonal inertia and damping matrices. By combining the novel state transformations, the direct Lyapunov approach, and the nonlinear time-varying tools, the stabilization and the trajectory tracking controllers are developed respectively guaranteeing global uniform asymptotic convergence of the state to the desired set point and global exponential convergence to the desired reference trajectory via mild persistent exciting conditions. Simulation examples are given to illustrate the effectiveness of the proposed control schemes. 
Ma Bao-Li
math.OC