Variable Collective-Pitch And Rotor RPM Quadrotor Aircraft Design Of Flight Control Based On QFT

Quad-rotor aircraft with its symmetry and simple body structure, superior hover and low speed performance and flexible manipulation becomes a new research hot-spot in the field of unmanned aerial vehicles(UAV).Small quad-rotor is always limited by its load and enduration time. However, the variable-pitch and variable-rotational-speed quad-rotor aircraft has higher pay load and longer enduration time. This article's focus on establishing its flight dynamics model,designing the flight control law, and conduct simulation in the MATLAB/Flightgear platform.First of all, the nonlinear flight dynamics model is developed, and the trim calculation, aircraft control input and coupling are analysised based on the assumption of small disturbance of the nonlinear model. Furthermore, the motion mode and main principle of the variable pitch variable rotational speed of quadrotor aircraft are known well.Secondly, based on the variable pitch and variable rotational speed quadrotor aircraft flight dynamics model and quantitative feedback theory(QFT), the attitude angle rate loop controller and filter is designed as the inner close loop which has good decoupling and tracking performance; outer control control loop(attitude loop, three axis translational velocity loop and position loop) using classical PID control theory is designed. MTALAB/Simulink simulation results show that QFT design of inner loop has strong anti-disturbance and decoupling performance, classical PID control of the outer loop has good control precision.Thirdly, a 3D real time visual joint simulation platform of MATLAB with the flightgear is established by using UDP communication protocol. 3D visual simulation experiment results further verify the performance of the control law.Finally, the hardware system of variable collective-pitch and rotor RPM quadrotor aircraft were introduced, and the flight experiment is conducted.