Research On Attitude Control System Of Four Rotorcraft

The quad-rotor aircraft is a complex nonlinear system,which is widely used in military and civilian fields by its characteristic of small structure、unmanned flight、varied control methods、low cost and autonomous flight,etc.However, due to interference and uncertainty factors,it is difficult to achieve a smooth flight.In order to solve this problem,it has a very important research value for the problem of attitude stabilization.Therefore,this thesis takes attitude control as research topic,and the main research work is summarized in following aspects:(1)Considering the project background,development history of the quad-rotor aircraft was introduced and the current main control methods are set forth.Meanwhile the flight principle、Kalman filter algorithm and quaternion are analyzed.(2)Taking the control requirements and required functions into account,we design the hardware and software of quad-rotor aircraft based on the STM32F103VCT6micro-controller.( 3) Based on the dynamic model,six state channels of the quad-rotor aircraft are controlled by cascade PID control.In the case of a channel,simulating this model by the classical PID algorithm, fuzzy algorithm, fuzzy PID algorithm in MATLAB.Then the improved discrete sliding-mode controller is designed and the simulation comparison by the traditional and the improved discrete sliding-mode control are given.Finally,in order to improve the control effect,the optimized neural network sliding-mode controller is designed aiming at the inconvenience choice of the reaching law constant,that is,use the output of BP neural network instead of the conventional reaching law constant ε、δ.(4)The flight control algorithm is tested and hardware and software are debugged on the testing platform of F450.In a word,based on the dynamic model of the quad-rotor aircraft, fuzzy PID controller、improved discrete sliding-mode controller 、 the optimized neural network sliding-mode controller are designed.These improved methods have better control effect than traditional control methods,which provide the theoretical basis for the future study.Then the hardwareand the software of the quad-rotor aircraft is designed and the quad-rotor aircraft achieve a smooth flight by cascade PID algorithm,which provide the test platform in order to achieve multi-functional research.