An Electromagnetic Attitude Control Method And Experimental Study On Rotorcraft

With the successful take-off of the U.S.Rotor UAV on the surface of Mars in 2021,it marks the first time that mankind has achieved a controlled flight outside the ground,demonstrating the great potential of the UAV for extraterrestrial exploration.Rotor-wing UAVs mostly adopt an automatic swashplate attitude adjustment configuration with a complex linkage mechanism,which is not conducive to miniaturization and lightweight design,and there is a problem of high risk of mechanical failure.This paper proposes a new attitude adjustment method that replaces the automatic swashplate attitude configuration.The method uses the magnetic control of the rotor generated by the electromagnetic coil to simulate the automatic swashplate periodic pitch adjustment to realize the attitude adjustment of the rotary wing UAV,and the electromagnetic variable pitch rotor system is designed.And the feasibility of the attitude adjustment of the electromagnetic variable-pitch rotor system is verified through experiments.Based on the principle of cyclic variable pitch motion of the rotor to realize the attitude adjustment of the UAV,an electromagnetic variable pitch rotor attitude adjustment method that can replace the automatic swash plate variable pitch function is proposed.The mathematical model of the rotor hinge torque considering the elastic deformation of the blade is established by using Hamiltonian principle,and the variation law of the blade hinge torque,the blade pitch angle and the rotor speed under the action of periodic variable pitch is analyzed,and it is established based on the equivalent magnetic charge theory.The mathematical model of the moment of the magnetic steel deflected by the electromagnetic coil is substituted into the initial structural parameters of the rotor and the electromagnetic unit,and the magnitude of the magnetic steel deflection moment and the peak value of the blade hinge moment is compared,and the feasibility of the magnetic control of the pitch change of the blade is verified.Based on the principle of electromagnetic variable-pitch attitude adjustment and preliminary structural parameters,the design requirements and overall plan of the rotor system are formulated,and each functional unit of the electromagnetic variable-pitch rotor system is designed in detail.In the rotor unit,through the structural design of an integrated blade and hub,the movement function of the rotor unit rotating around the main shaft and deflecting around the pitch axis is realized.In the electromagnetic unit,the electromagnetic simulation software Maxwell is used to optimize the structural parameters of the electromagnetic coil and the magnetic steel.Experiments have verified the feasibility of the designed electromagnetic coil and the magnetic steel to manipulate the pitch of the blade,and the electromagnetic coil drive and control design is completed.It realizes the function of simulating periodic pitch change of electromagnetic coil.In the attitude control unit,through hardware and program design,the attitude perception,calculation and control functions of the rotor system’s roll angle and roll azimuth angle are realized.An experimental test platform for the electromagnetic variable-pitch rotor system is built.The platform detects the six-dimensional force and attitude motion angle of the rotor system in real time.The platform is used to carry out experimental research on the mechanical characteristics and attitude control characteristics of the electromagnetic variable-pitch rotor system.It is verified that the rotor system can generate a roll control moment with stable amplitude and phase angle,and the change law of the amplitude and direction of the rotor roll moment under the action of different electromagnetic coil input voltage,rotor speed and attitude adjustment azimuth angle is analyzed.Based on the attitude control algorithm,the active hovering and azimuth roll of the rotor system are realized,which verifies that the electromagnetic variable-pitch rotor system has the feasibility of attitude adjustment.Based on the test platform,the rotor can be hovered and specified in any initial attitude.Stable side inclination of the angle.