Software Design Of The Navigation System For Quadrotors

Small scale quadrotors is a novel VTOL unmanned aerial vehicle with small volume,simple structure and convenient control.Nowadays it is widely used in performing complex tasks including surveillance,rescue and mapping.However,unmanned aerial vehicle(UAV)is a nonlinear,strongly coupled and under-actuated system,which involves Aerodynamics,Electromechanics and Automatic Control,etc,make it a difficult spot and has high research value.So it attractes many scientific research workers all over the world on account of the application value and unique research value.According to the actual needs of four rotor aircraft autonomous navigation system,the research designs the hardware structure,single-chip microcomputer software and PC software.Then realized the function of autonomous navigation,mainly finished the following work:(1)The overall structure was designed before the subject research.The main CPU and other sensors were selected after considering the navigation precision and processing speed of main control chip.The type of main controller is ATMEGA2560;the sensors here contains MPU6050(micro inertial sensors),HMC5883L(electronic compass),ATK-NEO-6m(GPS),MS5611(barometer).(2)After overall structure designing,the article introduced the principle of quadrotors and divided the quadrotors into two parts that containing the mechanical model and dynamic model.Mechanics modeling contains rotor modeling,motor modeling and body modeling.Dynamic modeling contains angular motion modeling and position movement modeling.Through analyzing the system model,nonlinear and strong coupling feature are noticed.(3)Linear model was built through LPV method after small Angle assumption and slow motion assumption were confirmed.PID-PID method is used for position controller and classic PID method is used for hovering controller based on simplified model.In view of the slow response of system to hop signal,differential tracker replaces classical PID method on hovering controller.Finally,Matlab/Simlink simulation was used to prove the advantage of arithmetic.(4)Attitude detection system was designed.Attitude updating through differential equation and attitude correction through multi-sensor fusion technology.MPU6050 module can provide the original triaxial acceleration and angular velocity data,HMC5883 L module can provide the original magnetic heading angle data.The Mahony complementary filter method was used to fuse the pitching data and rolling data,then the course angle was fixed.(5)Waypoint fighting function is implemented.GPS module provided the longitude and latitude data,Target location information was provided by the ground control station.Aircraft adjusted attitude to the destination through position error calculation.(6)PC software was written using the c # language,which contains Posture display,waveform acquisition,digital map loading and waypoint writing function.Destinations are written to main controller through a serial port before the test.(7)Ground control station test and aircraft flighting test were completed,then the results was analyzed.Ground station functions are implemented,attitude displaying instrument can display gesture accurately,waveform acquisition instrument can get attitude data and waypoint writing instrument can set the navigation path for Quadrotors.The hover stability and waypoint flighting stability were verified through flighting experiment.