Tilt-quadrotor:Modeling And Simulation Research

In recent years,with the rapid development of MEMS technology,navigation system with only a few grams weight has been developed.With the gradual maturity of the control algorithm,as well as the emergence of relatively faster microcontroller,the research and use of quadrotor are greatly welcomed in both military and civilian area.However,there are still many deficiencies in the quadrotor.The standard quadrotor takes on an underactuated feature,that is,six outputs are controlled by four inputs,which leads to the interconnection between the attitude control and position control of the aircraft.The maneuverability and movement mode of the quadrotor are greatly restricted,which seriously hinders the development of the aircraft application.In this paper,the dynamic model of the ordinary quadrotor is established,with the method of mechanism modeling,based on the detailed analysis of the force and moment.The controller is designed using the classical PID algorithm.Then,the structural issues of the strong coupling between the position and attitude of the quadrotor and the underactuation of the whole system are explored.This paper proposes two solutions for the issues above.One solution is to tilt a pair of rotor,and the other is to tilt two pairs of rotors.The mathematical models are also established for the two types of quadrotors by the method of mechanism modeling,meanwhile,the PID controllers are designed for them.In this paper,the model and the controller are verified by simulation under the environment of MATLAB/SimuLink package.The simulation results are shown to be consistent with the theoretical analysis.In the case with a pair of tilting-rotor,the linear motion of the quadrotor can achieve the decoupling with the roll angle.The aircraft can still achieve hovering or movement in any direction in the y_m o z_m plane,even if the roll angle is not zero.However,the linear motion of the aircraft will still be affected while the pitch angle changes.In the case with two pairs of tilting-rotors,the linear motion of the quadrotor can completely achieve the decoupling with the attitude angle,that is,the aircraft can move in any direction in the space while both the roll and pitch angles are not zero.