Design And Experimental Analysis Of A New Magnetically Suspended Gyroscope Flywheel

The new magnetically suspended gyroscope flywheel(MSGFW)has the dual functions of control torque output and attitude sensitivity of gyroscope,which can meet the functional requirements of new generation of satellite platforms to achieve fast maneuverability,very stable and super static.In order to improve the control accuracy and reduce the power consumption,the new magnetically suspended gyroscope flywheel adopts the hybrid support methods of magnetic resistance and Lorenz magnetic bearing.The magnetic resistance is used for load-bearing,and the Lorenz force is used for deflection control.In this paper,the new magnetically suspended gyroscope flywheels are studied in the following aspects:(1)In order to overcome the negative torque generated by magnetic bearing system under deflecting condition,the advantages of different schemes are compared and analyzed before a new MSGFW based on spherical rotor is chosen,and its structure and working principle are introduced.On this basis,the material characteristics of the MSGFW system are analyzed,and the three axis translational decoupling spherical magnetic bearings and the Lorenz magnetic bearing for twist suspension are designed.The main interference factors of the gyroscope are analyzed,and the minimum precision requirements are given respectively.According to the design results,the spherical center coincide degree is corrected by three-coordinate measuring machine.(2)There is coupling between different control channels which is due to the fact that the centroid of spherical rotor does not coincides with the geometrical symmetrical center of spherical rotor and testing center of spherical rotor,and as a result,an optimal design method of three hearts coincidence is proposed.The spherical rotor is introduced in detail,and the control model of the rotor system is analyzed.It is concluded that when the centroid of spherical rotor coincides with the geometrical symmetrical center of spherical rotor and testing center of spherical rotor,the suspension control channel of the spherical magnetic bearing can be made to be completely decoupled,and the controller design is simplied.In consideration of the maximum equivalent stress of the spherical rotor system,the ratio of polar moment of inertia to equinoctial inertial moment,the first-order resonance frequency,and the polar moment of inertia.The maximum deformation and the deviation of the centroid of the spherical rotor and the sphere center of the spherical rotor are increased as constraint variables.The high sensitivity parameter is selected as the optimization design variable and the optimization objective is to minimize the mass.The multi-disciplinary optimization design of the spherical rotor is carried out.(3)The structure and working principle of Lorenz magnetic bearing are analyzed in detail,and the best scheme is selected through comparative analysis.The magnetic circuit of the best scheme is analyzed by the equivalent magnetic circuit method,and its mathematical model is established.It is concluded that the deflection current stiffness of Lorenz magnetic bearing is proportional to the magnetization length.Through comparison and analysis,it can be seen that the edge angle of permanent magnet and the thickness of paramagnetic sleeve are the important factors in affecting the magnetic density uniformity of Lorenz magnetic bearing.On this basis,the magnetization length,paramagnetic thickness and permanent magnet corners are optimized by using the ANSYS18.0.Based on the principle prototype,the air gap magnetic density of Lorenz magnetic bearing is tested.(4)Aiming at the radial vibration amplitude of the rotor system of the flywheel caused by the imbalance is larger in the state of high speed rotation,a feedforward suppression method is proposed to control the system.The model of magnetic bearing rotor system is established.Based on D’Alembert’s principle,disturbing forces generated from unbalance mass moments and centrifugal forces caused by misalignment between geometric axis and inertia axis are obtained.The simulation of the rotor system is carried out based on the theoretical analysis results.On this basis,the experimental verification of the magnetic bearing flywheel and the new MSGFW system are carried out,and the experimental results are in accordance with the simulation results.