Aircraft Attitude Control Method During Distraction Magnetic Compensation Learning Flight

Geomagnetic navigation system has been widely used as auxiliary system in aviation,aerospace and marine engineering field,because of its particular advantages,such as no error accumulation,good concealment,low cost and so on.It has been combined with inertial navigation system to finish the navigation tasks all around the world.However,there exists distraction magnetic field,which influence the measurement accuracy of magnetic field,and it will decrease navigation accuracy and the effect of task.Aircraft distraction magnetic compensation learning flight is a kind of aeromagnetic compensation method,which asks aircraft do standard attitude motion,and it is very important.Therefore,it is significative to study the aircraft attitude control method during distraction magnetic compensation learning flight.Traditional aeromagnetic compensation method based on Leliak model can establish distraction magnetic field model basically accurately,which uses equation set including sixteen parameters to calculate model,and this method is the standard method to aeromagnetic compensation in engineering by far.However,this method does not take coupling phenomenon among three axises into consideration,and cannot use magnetic data sufficiently,and ignore the possibility of strange phenomenon.Therefore,this paper aims at the disadvantages above,and proposes a new aeromagnetic compensation method,which is based on fuzzy adaptive kalman filter.Furthermore,due to sliding mode control(SMC)based on reaching law theory can resist interference,and has robustness on parameters' variation,this paper improves the traditional reaching law,and proposes double power reaching law of SMC and mixed reaching law of SMC.Theory proves that these two reaching laws have existence and reaching condition,and aircraft attitude control system has stabilization under both of them.There is a detailed analyses about reaching rate.Aircraft attitude control system is considered as discrete-time system in this paper,and the two proposed reaching laws are applied in aircraft attitude control system,simulation results show that this method's effectiveness and advantages.The main researches in this paper are as follows:1.Distraction magnetic field and its constituent parts have been studied,and the mathematical model of every constituent part has been established,and aircraft attitude model has been proposed.Furthermore,the mathematical model of distraction magnetic field caused by aircraft attitude motion has been proposed.2.Traditional aeromagnetic compensation method based on Leliak model has been analysis,and for its disadvantages,a new aeromagnetic compensation method,which is based on kalman filter has been proposed.Then,the kalman filter has been improved into fuzzy adaptive kalman filter in order to make the estimation more exactly.3.Sliding mode control of discrete-time system and its reaching law method have been studied,and the advantages and disadvantages of traditional reaching law of SMC have been discussed.Then,double power reaching law of SMC and mixed reaching law of SMC have been proposed in this paper.Simulation results show that this method's effectiveness and advantages.4.The discrete-time form of aircraft attitude model has been deduced,and aircraft attitude model has been decomposed into pitch channel,yaw channel and roll channel.Furthermore,the two proposed reaching laws have been applied in aircraft attitude control system.Simulation results show that this method's effectiveness and advantages.