Modelling Based On Experiment And Control Technology Of An Oblique Cross Quadrotor

Quadrotor is a kind of excellent,novel vertical take-off and landing Unmanned Aerial Vehicle forboth military and civilian usages. Oblique Cross quadrotor is a variant of quadrotor, with larger viewof angle, which is more suitable for taking photos than the conventional cross-shaped quadrotor.After summarized the development prospect and the research status of quadrotor, the flightcontrol mode is analysed according to the structure of the oblique cross quadrotor. The kinetic modelis established. The model of the motor, which drives its flight, is also established. Then, a set ofexperiment is designed to identificate the parameters.In order to obtain the more accurate model, design the system identifacation experimentarrording to the Least-Squares identification algorithm. The linear model of the angle rate near thehovering state is identified. The results show that the model estabilshed can reflect the characteristicsof system validly. Compared with simulation result of the model made up by theroy derivation andparameters measurement, the model established by system identification is more accurate.Accordding to the classical PID algorithm, a flight control system is designed. The systemcontains three loops: the augmentation loop with angle rate feedback, the attitude control loop and theposition control loop. The simulation results show that with the PID control strategy, the quadrotorcan reach the target positon accurately and keep its stabilization when hovering.Finally, a control strategy is designed based on the backstepping method to cope with thequadrotor’s nonlinear and sub-actuate dynamic model. The structure of this system is different fromthe PID control system, which is just consisted of the attitude control loop and the position controlloop. The simulation results indicate that the backstepping controller has better control effect insystem response overshoot, rise time and settle time, than the PID controller.