Multi-stages robust autopilot for nonlinear command line of sight guided system

The performance of guided flight missile systems is measured through the minimum miss-distance and its capability to overcome target maneuver in presence of different sources of disturbances and noises. To achieve this objective, mathematical model for different dynamical behavior phases of command to the line of sight (CLOS) system is introduced using system identification technique. However, these mathematical models cannot precisely represent a real physical system without uncertainties. To improve system performance, a multi-stages robust autopilot is designed (each stage applied with corresponding missile flight phase) and compared with single stage robust autopilot. By using the H_∞ approach, both controllers are obtained to adequate the nonlinear dynamical behavior and overcome different kind of uncertainties of the intended Command Line of Sight Guidance System (CLOS). Finally, the system performance and robustness are verified with flight path analysis by 6-DOF simulation model.