| As the key technology of modern carrier/carrier-based airplane system,the Automatic Carrier Landing System(ACLS) has been widely researched and cared. ACLS is used to guide and control carrier-based aircraft to safe land on the moving deck of carrier under all weather conditions and sea states.The design of ACLS is really a complicated process,which include the knowledge of flight mechanics, aerodynamics,ship dynamics,navigation and control,etc.In this paper,normal ACLS is designed;the control effect of ACLS is analyzed and researched.An improved method for longitudinal control laws is also developed.Firstly,the motion and mechanics of carrier-based airplane during approach and landing period is analyzed according to flight mechanics knowledge to build the airplane state space equations with perturbation.With the responses of the airplane, the approach and landing airframe characteristics are analyzed.Since carrier motion has the characteristics of stationary random process,power spectral density model is built to reflect the real motion of carrier at sea.The characteristics and causes of carrier airwake are analyzed and the model of airwake is simulated by an industrial method according to US Navy criteria.With the brief structure,ACLS is designed from inner loop to outer loop. Automatic flight control system,approach power compensator system,guide control law and deck motion compensator are researched designed respectively.They are integrated in Matlab/Simulink and verified by simulation.According to the characteristics of ACLS,the longitudinal guide control law is improved by using fuzzy PID controller.Fuzzy control system is designed to regulate the parameters of controller online.With the simulation in Matlab,this method is proved to increase the airplane's landing quality. |
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