The Research On Attitude Control Of Coaxial Dual Rotorcraft In Hovering State

The coaxial double rotor aircraft has been widely used in military and civilian because of its compact structure,high hover efficiency and good maneuverability.In order to make the coaxial double rotor aircraft has a good effect of flight and maneuvering performance in a relatively narrow space,the higher requirements about its control performance have been put forward.This paper studies on the flight attitude control of the coaxial double rotor aircraft.Based on the performance requirement of the coaxial double rotor aircraft,this paper selects brushless dc motor with hall sensor as the actuating device of the coaxial double rotor aircraft.After a detailed discussion on the basic structure and working principle of coaxial double rotor aircraft,the mathematical model has been established.Using Matlab7.10.0/Simulink to build the system control model,the simulation results show that the proposed control strategy has good performance.Based on the flight control requirement of the coaxial double rotor aircraft,and the sufficient grasp of the basic structure,the working principle and the law of motion about the coaxial double rotor aircraft,this paper introduces the method of simplified model to establish nonlinear dynamic model of the coaxial double rotor aircraft according to the theory of mechanics and kinematics of rigid body mechanics of rigid body and kinematics,which provides the related basis for the design of flight control system.Based on the nonlinear dynamic model of the coaxial double rotor aircraft,in order to improve the attitude control's accuracy and stability of the coaxial double rotor aircraft,a flight attitude control method of the coaxial double rotor aircraft based on Incremental control algorithm with an automatic correction factor is presented,which refers to the three channel of the coaxial double rotor aircraft including pitching,yawing,rolling.The experimental results show that the proposed method can reduce the attitude angle deviation rapidly,improve the dynamic response of the system,and enhance the control precision and stability performance of the vehicle effectively.The whole structure block diagram of the system is built based on STM32 microprocessor.Altium Designer software is used to design the hardware circuit in the hardware part,main control chip and peripheral circuit,etc.The software part is developed by an approach of modular structure,including the main program,interrupt program,I2 Cand PWM program,etc.Programming of software program with Codeblock emIDE development tool.Perform the system test after completing the above work.The test result on the experimental has fully verified the feasibility and reliability of the proposed control strategy.Theoretical research and experimental results show that based on the actuating device of the coaxial double rotor aircraft has good static and dynamic performance,PID control algorithm with a automatic correction factor on the basis of the nonlinear dynamic system model can control flight attitude of the coaxial double rotor aircraft effectively.