Enhanced Sliding Mode Control for Missile Autopilot Based on Nonlinear Disturbance Observer

For the longitudinal dynamics of a highly maneuvarable missile, an enhanced sliding mode controller (SMC) based on nonlinear disturbance observer (NDO) is proposed. This scheme allows a continuous control robust to external disturbance and uncertain aerodynamic coefficients without the use of high control gain or extensive computational power. When the structure of whole control system is fixed, genetic algorithm (GA) is used to optimize the parameters. Simulation results show that the proposed scheme can track the maneuver command with better performance and robustness than conventional sliding mode controller.