Nonlinear Feedback Linearization Method In The Flight Control System

The problems of stability and reliability are the most urgent problems to be solved in the field of Aircraft Control. As the complexity of flight tasks increases, the linearized equation based on the small disturbance theory is no longer adequate for the design of control systems, and the necessity of exploring a nonlinear approach seems increasingly obvious. Firstly, the method of feedback linearization is adopted to design the automatic landing system. The original nonlinear system is linearized to one one-order system and one two-order system. Then design methods for linear systems are adopted to design each system separately. Secondly, classical control method is used to design control laws. Parameters are determined in order to obtain satisfactory system performance. The method of forward feed control is used to reduce the tracing errors during glide slope phase. Different control laws are designed to fit the two phases of flare control and glide slope control separately. Finally, the air disturbances including horizontal wind, vertical wind and gust are considered in the landing process.The simulation results show that the designed landing system possesses not only satisfactory performances but also strong robustness.