Multidisciplinary Optimization Design And Experiment Of Magnetic Suspended Flywheel Rotor

As the increase demand for high-altitude reconnaissance technology and Earth observation technology,the requirements for torque precision and the vibration control precision are higher than before.Traditional mechanical flywheels with the limitation of zero-cross friction,viscous moment,friction and wear,need for lubrication and relatively low life are supported by mechanical bearings,which limit the further improvement of flywheel performance.The magnetic suspended flywheels with the advantages of no friction and wear,no lubrication,no viscous torque and long relative life are supported by magnetic bearings.They can meet the requirements of the new generation spacecraft for attitude controlling,and they are considered as ideal inertial actuators.The content of this article are as follows:(1)Design of optimal flywheel suspension scheme.In order to ensure that the magnetic suspended flywheel can output high-precision torque and meet the spacecraft’s attitude control requirements,a structure scheme of magnetic suspended flywheel that axially controls the rotor deflection was selected by comparing the magnetic suspended flywheel solutions of different structures.Based on the scheme of magnetic suspended flywheel above and the characteristics of the flywheel body,appropriate materials were selected to applying different flywheel body parts,and the main structural parameters of the flywheel system were given based on actual engineering experience.As for the technical problems of vacuum sealing for magnetic suspended flywheel,a general design method of magnetic suspended flywheel sealing system was summarized.As for the working characteristics of the magnetic suspended flywheel,a co-location design of detecting and controlling for magnetic bearings and sensors was proposed,and a spherical protective bearing was designed for the spherical flywheel rotor.In order to make the magnetic bearing fast stabilize and suppress the vibration of the flywheel system,a structural design of Lorentz force magnetic bearing with deflection axial damper is proposed.As for the problem of insufficient rigidity of the existing implicit Lorentz force magnetic bearing,a high-stiffness implicit Lorentz force deflection magnetic bearing was proposed.Finally,a general Lorentz force deflection magnetic bearing design method is summarized,which provides a good reference for the design of Lorentz force magnetic bearings.(2)To make the magnetic density of the air gap large,the structure design of the magnetic levitation motor was optimized.In order to maximize the magnetic flux density in the air gap of the magnetic suspended flywheel and reduce the flywheel systems power consumption,the structural size of the magnetic suspended flywheel motor is optimized based on the existing engineering technology requirements.Through the derivation of the gyro dynamic equation,the ratio of the polar inertia moment to the equatorial inertia moment of was calculated and analyzed so that the precession and nutation have little effect on the rotor when the flywheel rotor runs stably.The dimensions of the permanent magnet and the inner and outer magnetic conduct rings were set as design variables,and the air gap magnetic density was used as the objective function.The optimization software Isight was integrated with the finite element software ANSYS,and the motor structure is optimized by using the Sequential Quadratic Programming method.Optimal magnetic density was obtained eventually.(3)To minimize the mass of the rotor system,the structure of magnetic suspended flywheel rotor was optimized.Most of the optimization of magnetic suspension flywheel rotor focuses on the optimization of the magnetic circuit topology and control system.In order to improve the overall performance of the flywheel,based on the actual needs of the existing magnetic suspension flywheel engineering,the condition of the rotor’s radial translational channel decoupling was derived by the gyro mechanics control theory,and the magnetic bearing controller was simplified.The relevant dimensions such as the flange and spokes of the flywheel rotor assembly were used as design variables,and the constraint variables are set based on actual engineering requirements.The conditions for decoupling the rotor’s radial translational channel and the ratio of the polar inertia moment to the equatorial inertia moment were also set as constraint variables,and the minimum rotor mass was set as the objective function.The optimization model of the flywheel was established,and the optimum rotor structure was obtained eventually.(4)Based on the above optimization results,a prototype of a magnetic suspended flywheel was manufactured and a prototype test platform was built.The first-order resonance frequency of the rotor was measured by an oscilloscope and compared with the simulation results of the rotor modal to verify the accuracy of the optimization method and results.The effectiveness of the optimization was verified again by unbalanced vibration simulation experiments and the rotor radial translational channel decoupling experiments.The off-line dynamic balance experiment of the rotor was used to reduce the unbalance of the rotor,and the steady-state power consumption and the maximum transient power consumption of the flywheel were measured to verify that the power consumption of the flywheel meets the requirements of the magnetic suspended flywheel.