Research On Power System Modeling And Propeller Failure Performance Evaluation Of Multi-rotor Electric UAV

With the development of UAV technology,multi-rotor UAV,as a unique branch in the field of aircraft products,has rapidly become a new research hotspot in the world for its novel structure layout,unique flight mode and wide range of applications.Multi-rotor aircraft is to use the lift force generated by rotor rotation for energy conversion and transmission.Its power system performance directly affects the flight quality.At present,the problems existing in the research on the performance of multi-rotor aircraft power system are that the establishment of rotor aerodynamic model is limited by the experimental equipment and system.Most of the studies are based on theoretical analysis or numerical simulation conclusions,and the modeling assumptions are many,the interaction between rotor and air is uncertain,and the model accuracy is difficult to meet the actual flight requirements.In order to improving the aerodynamic characteristics of the rotor,enhance the performance of the power system of the multi-rotor UAV and enhance the flight quality,this paper takes the micro-quadrotor electric UAV as the research object,conducts the following research:Firstly,the flight principle of the multi-rotor UAV is briefly described,and the basic method of attitude control is described.The basic parameters such as airfoil parameters and working state parameters of the propeller are introduced,and the aerodynamic parameters of the propeller are calculated based on the blade element theory.The force of rotor blades during air flow is systematically analyzed to reveal the influence of different rotor blade parameters on the aerodynamic performance of the aircraft.Based on the aerodynamics calculation method of multi-rotor electric UAV,combining theory with practice,a special experimental device for performance test of UAV power system is designed and developed.The working principle of the experimental device and the matching data acquisition and data processing software are introduced.Secondly,the experimental design of UAV power system performance was completed.Based on the determination of the motor,electric control and battery of the power system,the propeller power system parameters were tested,and the experimental data were preliminarily analyzed.The voltage and current measurement module of the experimental platform and the UAV battery balance charger were used to test the discharge curve data of the selected battery.A matching method of UAV propeller and power system is proposed,and a suitable type of propeller is selected for UAV.Thirdly,the APC10070 propeller selected above is used to build the UAV power system model,including propeller model,motor model,electronic governor model and battery model,based on the obtained power system performance data.Based on the established propeller model,the least square method was used to fit the experimental data above with Matlab software,and the model parameters a _T and a _M of different propellers were obtained.Finally,14 APC10070 propellers of 5 different failure forms and different failure degrees are chosen for aerodynamic performance test.Artificial neural network was used to fit the experimental data of different types and degrees of failed propellers,and the mathematical models of thrust and torque of failed propellers were obtained.Aiming at the rotor propeller,a key component of the power system,the internal relationship between its failure mode and dynamic performance was studied.According to the mathematical model of the powertrain and the failure model of the failed propeller,combined with the failure law of other powertrain components such as motor,electric regulator and battery,the powertrain health assessment strategy was established.