Flight Control Of Micro-quadrotor Unmanned Aerial Vehicles

A micro-quadrotor unmanned aerial vehicle(UAV)is a kind of aircraft with simple mechanical structure in six degree of freedom motion.It can accomplish many complex tasks and flight in complex scenarios so that it is widely applied in various fields.In addition,the micro-quadrotor UAV has the nonlinear and underactuated features with strong coupling which leads to great challenges in modeling and the design of the controller of the flight control system.In this paper,a nonlinear dynamic model of a micro-quadrotor UAV is established based on its structure and flight principle based on which a simplified model is derived.The classical PID controller is first designed and simulated via the MATLAB/SIMULINK.The results show that the classical PID control can effectively control the micro-quadrotor UAV,but the convergence speed is slow,and the robustness and the tracking effect are poor.To cope with the problem occurred in the classic PID control,a sliding mode controller is then proposed.The simulation results demonstrate that compared with the classical PID controller.Nevertheless,the sliding mode control yields serious chattering and tracking error of the attitude angles,which is not applicantable in practice.Finally,an integral sliding mode controller based on double power reaching law is presented.Simulation results show that the integral sliding mode controller of double power reaching law achieves excellent performances,i.e.,the control curve is smooth without steady-state error.