Structural Design And Magnetic Field Characteristics Of A Novel Magnetic Suspension Rotor

The magnetic levitation rotor is a new application of the magnetic levitation principle on the rotor of an aircraft.The China Helicopter Research Institute first proposed to use the principle of magnetic levitation support to the rotor blade support,and jointly conducted a preliminary study on the magnetic levitation rotor by the magnetic levitation research group of Wuhan University of Technology in 2018.When the rotor of the aircraft is supported by the outer edge of the magnetic levitation,the tip vortex of the rotor blade can be greatly reduced,the problem of the tip waving during high-speed rotation is eliminated,and the utilization of the tip is improved,thereby achieving greater lift at the same propeller radial dimension.At the same time,due to the frictionless,rigid and adjustable damping characteristics of the magnetic suspension support,the vibration noise of the magnetic suspension rotor is reduced and the concealment is improved.In this paper,firstly,with reference to the previous two kinds of magnetic levitation proposed technology used in the outer edge of the support rotorcraft embodiment,the magnetic suspension support of the rotor is designed in detail for the performance requirements of the actual rotor.Then the dynamics modeling of the magnetic levitation support of the magnetic levitation rotor is carried out,and the two problems raised in the previous research are addressed: 1.The driving magnetic field of the disk motor in the magnetic levitation rotor affects the supporting magnetic field of the magnetic levitation supporting system and leads to the magnetic levitation support fail;2.The disc motor that provides the driving torque will produce the influence of the unilateral force on the magnetic levitation support system;theoretical,simulation and experimental research are carried out,and several criteria for the design of the magnetic levitation rotor are proposed based on the research results.Finally,the prototype experiment is carried out to verify the improvement of the utilization of the lift of the rotor tip by the magnetic suspension support,which indicates that the application of the magnetic levitation technology to the rotor is relatively successful.The main research contents of this paper are as follows:(1)Design the electromagnetic support structure of the magnetic suspension rotor according to the principle of magnetic suspension bearing.Three sets of magnetic suspension support schemes are proposed: pure EMS electromagnetic support,EDS/EMS hybrid support,and pure EDS electric support.With reference to the design process of the magnetic suspension bearing and the related principles of the rotorcraft design,the parameters of the axial and radial support of the magnetic suspension rotor were designed.Then the dynamic model of the EMS axial electromagnetic support was established and the dynamic stiffness of the mechanical structure was analyzed.The drive parts of the magnetic suspension rotor(including the disc motor and the rotor blade)were analyzed and selected.Finally,the relationship between the change of electromagnetic force and the total mass of magnetic suspension support is analyzed.(2)For the magnetic levitation support scheme designed in Chapter 2 and the selected disc motor model,the magnetic field characteristics of the two main parts of the magnetic levitation rotor are analyzed theoretically,including the respective magnetic path and magnetic density distribution.Using the finite element analysis software,combined with the specific parameters designed in the second chapter,the magnetic field numerical simulation analysis of the magnetic suspension support part and the disc motor was carried out to verify the correctness of the theoretical part.Then combined with the above theoretical analysis of the magnetic field of the two,the influence of the driving magnetic field of the disc motor on the EMS electromagnetic support and the EDS electric bearing is studied.The key structural parameters of the influence of the driving magnetic field on the magnetic suspension supporting magnetic field are obtained,and the finite element is passed.The variation of the influence of the driving magnetic field of the disc motor on the magnetic field of the magnetic suspension is simulated and analyzed.Finally,the binomial fitting is applied to the curve of the mutual influence of MATLAB,and the critical value of the key structural parameters is obtained.(3)According to the axial EMS support and radial EMS support structure of the magnetic suspension rotor designed in Chapter 2,the principle experimental platform of electromagnetic suspension characteristics of magnetic suspension rotor EMS is built.The axial EMS differential suspension experiment and the radial EMS equivalent suspension experiment are carried out.The critical dimensions obtained by theoretical analysis and simulation analysis in Chapter 3 are verified by experiments.Combined with the two major factors affecting the magnetic suspension support of the disc motor: the single-sided force of the disc motor and the peak magnetic field of the disc motor,corresponding design criteria are proposed for the magnetic suspension support part.(4)Through the prototype of the magnetic suspension rotor,the rotor lift using the magnetic suspension support and without the magnetic suspension support was initially tested.The results show that when the magnetic suspension support is adopted,the lift of the rotor will be increased which verifies the feasibility of the application of the magnetic suspension support on the rotor.