Robust adaptive finite-time trajectory tracking of underactuated ship

A finite-time trajectory tracking controller is developed to overcome the impact of dynamic uncertainties and external disturbance charactering underactuated surface ships. The design transforms the system dynamic uncertainty and external disturbance into a compound vector in single parameter linear form and devises an adaptive control law to approximate the upper bound of the vector, which effectively simplifies the calculation. The virtual control variables and control law are designed in the form of finite-time function for better convergence rate and noise immunity. The stability of the system is examined with Lyapunov stability theory. The effectiveness of the controller is verified through simulation.