Design Of Quadrotor Aircraft Control Systems

Four-rotor aircraft has broad prospects for both civilian and military,in recent years has attracted the attention from researchers.Quadrotor air vehicle is a four input output of the six under-actuated,strong-coupling,and nonlinear systems,which has brought great difficulties to the controller design.Quadrotor air vehicle's attitude control and hover control problems are studied in this thesis.A four-rotor aircraft prototype is built and the proposed algorithms are verified by simulation and experiment.The main work this thesis is as follows:(1)Starting from the principle analysis of the four-rotor aircraft,the dynamics model is established.We set up an experimental platform for four-rotor aircraft,including four-rotor aircraft mechanical structure design and material selection,hardware circuit and software system design.Hardware includes four-rotor flight control hardware and remote control hardware.Both of master chips choose STM32F103VET6,communicate with each other using Bluetooth 4.0 module HM-10.Software systems include remote control system and four-rotor aircraft monitoring control system.(2)This thesis is concerned with the problem of the attitude determination and control for a four-rotor aircraft plant.A third-order approximated Peano-Baker Quaternion algorithm is used to solve the attitude determination problem for the aircraft.The proposed algorithm combined with Kalman filter are introduced to avoid accumulated errors of gyroscope and to eliminate the sensor measurement errors induced by the four-rotor aircraft airframe vibration.Based on the obtained attitude solution,the integral separating PID and cascaded PID controllers are designed for the attitude control.Finally,a four-rotor aircraft platform is developed,and the effectiveness of designed attitude determination and control algorithms is illustrated by this platform.(3)A cascade active disturbance rejection controller is designed for the hover control of a quadrotor air vehicle in this thesis.First,a dynamic model of a quadrotor air vehicle is presented by applying the Euler and Newton theorem,where the model is further decoupled as a double loops and multi-subsystems structure.Then,a cascade active disturbance rejection controller is designed by taking the structural features of quadrotor air vehicle systems into consideration.A linear ADRC controller is designed for the external-loop to obtain a better loop input signal and a nonlinear ARDC controller is designed for the inner-loop to obtain better tracking performance.For the parameter perturbations within the system and the influence of the existing uncertainties of external disturbances,an extended state observer is designed for estimating the state and the sum of internal and external disturbance of the system,the nonlinear state error feedback control law is used upon this to compensate the disturbance and attenuate the influence of internal and external disturbance on the system.Finally,simulations are presented to verify the effectiveness and superiority of the proposed control method.