Robust missile autopilots with finite-time convergence

This paper presents a new longitudinal autopilot to address the finite-time tracking problem for uncertain agile missiles. The proposed autopilot is essentially a composite control scheme, which is obtained through the finite-time control methodology and the nonlinear disturbance observer (NDOB) approach. The key idea in this scheme is that the NDOB is adopted to estimate the aerodynamic uncertainties and external disturbances in an integrated manner. With the aid of the finite-time bounded function and the Lyapunov function method, the finite-time stability of the closed-loop system is established, which shows that the angle-of-attack response will converge to the external command signal in finite time. Numerical simulation results are presented to demonstrate the superiority of the proposed scheme.