Design And Experimental Research Of Coaxial Vehicle With Controllable Rotor Axis Angle

Existing configuration UAVs mainly include single rotor helicopter and multi-rotor UAV.The configuration and control principle of the coaxial aircraft with controllable rotor axis angle is different from the existing UAVs.The stability of this aircraft is better than that of the existing UAVs,the size of the aircraft is smaller than the existing UAV,and the continuous navigation ability and carrying load ability are better than the existing UAVs.Therefore,it is of great significance to study the coaxial aircraft with controllable rotor axis angle.At present,most of the new UAVs adopt the control mechanism which can use the main rotor lift to control the flight direction and attitude of the aircraft,such as changing the lift direction of the main rotor,changing the flow direction of the downwash air generated by the rotor,etc.,and a few UAVs use the interaction force between the fuselage and the air flow to generate lift and control force when the flight speed is fast.However,these new UAVs have some shortcomings,such as weak control moment,poor structural reliability and so on.In view of the shortcomings of the existing new configuration UAV,a coaxial aircraft with controllable rotor axis angle is proposed in this paper.By changing the angle of the rotor motor axis relative to the fuselage,the horizontal force component of the lift force of the aircraft is controlled,and then the flight attitude of the aircraft is controlled.Compared with the existing research,this control structure has the advantages of strong control moment,good reliability,compact fuselage,strong load capacity and long flight time.First of all,a compact control mechanism with small mass is designed for the proposed coaxial aircraft.The aircraft structure and the installation of electronic control elements are designed in detail,including power system,control system,fuselage,and sensor vibration isolation design.In the design to ensure the symmetry of the fuselage,so that its mass distribution balance is conducive to control.Secondly,the structure of the aircraft is simulated and analyzed and the lift test is carried out,and the structural strength analysis is carried out for the fragile part of the aircraft.By analyzing the aerodynamics of the fuselage,the force of the fuselage in the air flow can be obtained.The lift test of aircraft power system is carried out,and the lift test data obtained from the test can be used to control the aircraft better in the control algorithm.Thirdly,the hardware architecture of the control system of the aircraft is designed,its system function is analyzed,and the overall scheme design is carried out.And the overall control block diagram and aircraft control algorithm block diagram are designed.The position and attitude control algorithm in aircraft control algorithm is studied.The stability of the aircraft is proved,and then the coordinate system of the aircraft is established,and the horizontal acceleration analysis is carried out.And the position and attitude control algorithm is designed and expressed by the system block diagram.Finally,an aircraft test platform is set up to carry out the flight test of the aircraft,including the load-free experiment and the load experiment,to prove the rationality,feasibility and the effectiveness of the control algorithm of the aircraft.