Research On The Total Energy Control System Of Composite VTOL UAV Based On Px4

With the in-depth research and extensive use of UAV,the functions of UAV are becoming more and more diverse.Vertical take-off and landing(VTOL)UAV is a new type of aircraft with rapid development in recent years.The compound vertical take-off and landing UAV is also one of them.The system directly integrates the fixed-wing system and the four quadrotorsystem into the whole system,which not only retains the flight characteristics of the two systems,but also effectively avoids the complex mechanical transmission and tedious control procedures required by other UAVs.It is a kind of UAV with great development potential.With more and more flight practices of composite VTOL UAV,a result has been found that UAV's flight height can be changed by it's speed as the flight in fixed wing mode,or flihgt speed will be changed when operators only want to change flight height through pitching operation.For the reason,the controller can't control UAV's flight speed and height separatly as coupling characteristics of response from elevator and throttle lever in low dynamic pressure.Therefore,how to decouple is the key to improve flight quality of composite VTOL UAV.The total energy control is to use the method of energy control and distribution to decouple speed and height control,and adopt the way of throttle to manage total energy,elevator(pitch angle)for the purpose of controling dynamic and potential energy exchange.At last,flight quality of VTOL UAV can be improved sucessfully.Based on Px4 flight control system,this paper studies how to introduce total energy control into VTOL UAV control system.First of all,the background and significance of the research on compound VTOL UAV are introduced as well as the development status and main research contents at home and abroad.Secondly,the paper describes system composition of compound VTOL UAV and detailed process of building the UAV.The flight state of compound VTOL UAV is described in detail by two independent processes: four rotor state and fixed wing state.The preparation process and processing method for UAV flight are described,and flight test is carried out.After that,the framework of Px4 flight control system is analyzed and introduced.Then,a simulink modeling method is introduced in detail,which aims at composition characteristics of compound VTOL UAV system.Then,the origin of total energy control formula is deduced,and how to embed compound VTOL UAV control system is designed and simulated.Finally,total energy control is coded and design process is explained in detail,and simulation results are verified in the environment of gazebo.