Pid Neural Networks In Civil Aircraft Automatic Landing System

Flight control system has appeared even since the invention of aircraft. The aim offlight control system is to improve the stability and manoeuvrability of the aircraft andreduce pilot workload, so as to enhance the ability and efficiency of carry outassignment, and guarantee the safety of flights. The development of flight controlsystem has experienced the periods of stability augmentation systems (SAS), controlaugmentation systems (CAS), fly by wire control systems (FBW), and synthesizedcontrol systems. Auto landing system is an important part of modern flight controlsystem. With the development of redundance FBW flight control system usingmodern computer technology, the reliability of auto landing system has beenimproved greatly. It's easier and more flexible to realize the function of auto landingsystem than usual. In the future, the flight control system will be highly intelligentized,and auto landing system will be the remarkable label of independent flight controlsystem.The design of auto landing system is a challenging task. From the perspective ofcontrol theory, the core of auto landing system is to design an auto landing control lawwhich can make sure that the aircraft will track the landing contrail accurately, andland on the expected point safely.This dissertation includes in-depth studies on auto landing control system of civilaircraft. The flight law during landing period is studied, and PID neural network(PIDNN) is applied in this law.Firstly, the mathematic model of a civil aircraft is built. The nonlinear differentialequations are lined according the feature of flight and demand of simulation, and thelinear pitching equations and lateral equations are got, which predigest furthersimulation.Secondly, the structures and control methods of pitching channel and lateral channelare analyzed, according to the operation principle and using experience of flightcontrol system and instrument landing system (ILS).Then, according to the mathematic model and feature of aircraft landing, PIDNN isused in the design of auto landing control law of the civil aircraft, and the controller issimulated in MATLAB.Simulation results show that it improves the performance of the system effectively.