Flip Control For Multirotor In Aggressive Maneuvering

Multirotor UAVs(Unmanned Aerial Vehicle)are widely popular because of their compact and reliable mechanical structure,simple and stable control principle.Although multirotor UAVs(especially quadrotor)are becoming more and more powerful in the market,such as smart,clustered,professional,etc.,few studies have been made on the flight attitude of large aircraft maneuvers.The reason is the current market demand is not very high,but its potential demand is great,and can greatly reduce the owner’s property losses and ensure the safety of the operator and the surrounding personnel.Four-rotor UAV,for example,the study is active flip control of the aircraft,the main work is done as follows:Firstly,the development of multi-rotorcraft is introduced,including the trend of development for multi-rotor UAVs.Then the origin of the project is described,the basic knowledge about the composition of the multi-rotor aircraft system,the coordinate system used and the rotation matrix are briefly introduced.Secondly,based on the Newton-Euler formula,the dynamics model of hovercraft is established for the quadrotor.In the world coordinate system,the position loop differential equation is established according to the Newton’s second law.In the body coordinate system,the differential equation of the attitude loop is established according to the rotational dynamics knowledge.According to characteristics of hovercraft,the double closed-loop control method of PID controller for outer loop and PD controller for inner loop is selected,MATLAB’s simulink toolkit is used to simulate hover,and then this method is applied to the actual quadrotor.The simulation results and the actual control effect of double-loop control strategy are very good,and this method can achieve the hover control requirements.Finally,the flip control model is established,the three-phase control strategy is designed and the corresponding simulation and result analysis are made.When two motors rotate at the same speed on the same axis,the model can be simplified into a two-dimensional model.Then the flip process is divided into three parts,the first 90°,the last 90° and the intermediate 180°.To ensure body’s rotation speed is zero in final,the rotating torque is required equal in size and opposite in direction during the first and the last phase.The final position of the aircraft in horizontal and vertical directions can be controlled by adjusting the size of the lift.The simulation results show that the optimized three-stage method can achieve the requirements of flip control.