Modeling And Design Of Quadroter Helicopters Based On Variable Pitch Actuators

Compared with the fix-pitch quadrotor helicopter,variable-pitch quadrotor helicopter get control by changing each blade’s pitch angle.In this way,the speed of control response will be more quick and precise.It also proves a practica ble design that uses internal-combustion engine to drive the quadrotor which will significantly improve the endurance as well as payload.But it also makes the whole system more complex.In this this thesis,the research on quadrotor key techniques is made by the following aspects.(1)The development of rotor helicopter and the key techniques which related to variable-pitch quadrotor is described and summarized.The motivation of the research is introduced.(2)The model of variable-pitch quadrotor is established,including six degrees of freedom motion equation as well as motor-propellers.Through decoupling and linearization,the liner model is obtained.Designed experiment is conducted to get the moment and force coefficient of variable-pitch propellers.It is proved by simulation that the response of control is quick and precise.(3)Carry out the synthetic design of variable-pitch quadrotor helicopter,Taking the takeoff weight as the starting design point.Get other key parameter by formula derivation,including hovering power,radius of propeller,motor power as well as physical dimension.Different transmission structures like single shaft gear and toothed belt are compared.variable-pitch quadrotor helicopter is built according to the design result.(4)The PID controller is designed,Take attitude loop as inner loop,position loop as outer loop.Inspect design result by simulation of non-liner model.The result shows that PID controller could achieve the attitude and position’s stable control.(5)Design and develop the autopilot on the basis of open source autopilot,Achieving the variable-pitch quadrotor stable control by design and replace its former control apportion model.