The Performance Optimization And The Model Of Permanent Magnet Moving-coil Linear Motor Of Electromagnetic Launcher For Unmanned Aerial Vehicles

As a new type of Unmanned Aerial Vehicle(UAV)launching mode,electromagnetic launching has broad application prospects.It is a suitable choice to apply it to the launching of fixed-wing UAV.For land-based fixed-wing UAV electromagnetic catapults,good maneuverability is required because they are usually carried or towed by vehicles.As the main influence part of maneuverability,linear motor for launching needs to improve the performance of UAV launching system on the premise of the good maneuverability.In view of the problems existing in the actual launching process of the existing moving-magnet linear motor,such as lack of maneuverability,large thrust fluctuation and large normal force,a moving-coil type of permanent magnet linear DC motor is designed.In this paper,the performance optimization of this linear motor for ejection is studied.The main research contents are as follows:Aiming at reducing the influence of thrust fluctuation and normal force,the thrust of moving coil linear motor is analyzed by Maxwell tensor method.It is pointed out that the air gap magnetic field is the main factor affecting the thrust and thrust fluctuation.Finite element simulation and parameter regression analysis are used to find out the parameters that significantly affect the air gap magnetic field and then optimize them,so that the thrust of linear motor increases and the thrust fluctuation decreases significantly.For the normal force,the Fourier expansion method is chose to optimize the reduce the influence of normal force.Pointing the problem that the parameters back EMF,resistance and inductance in the linear motor model may change and make the accuracy of the control of the linear motor worse,the back EMF is identified offline,the resistance and inductance are identified offline by least square method,and the resistance and inductance are identified online by Kalman filter method,which provides the necessary parameters for the control of moving coil linear motor.The simulation results show that the resistance and inductance parameters are insensitive to the position of the rotor and can be regarded as constants.In order to verify the effect of optimization,a 1.5m double-sided moving coil permanent magnet DC linear motor model is made.Combining a speed and position control strategy,the thrust performance of the moving coil motor model prototype is verified experimentally,and the thrust is reduced by compensating the current with the back EMF coefficient.The results show that the designed movable coil linear motor has smaller thrust fluctuation and better performance than the original moving magnet linear motor,which lies the foundation of the following study.