Study On Vibration Analysis And Vibration Suppression Control Of Magnetic Suspended Flywheel System

Magnetic suspended flywheel (MSF) as a novel actuator for spacecraft attitude control has advantages of extremely low friction, high precision and long operational life, etc., and thus is an important research direction on space technology. However, pointing accuracy of spacecraft will be decreased by vibration and jitter occurred during MSF operation. The vibration of MSF is issued in the dissertation, MSF's dynamic model, nonlinear vibration response, coupled vibration with mounting platform, and methods of vibration suppression control are studied systematically.A method using 3D finite element analysis on electromagnetic field is proposed to obtain the nonlinear electromagnetic force of MSF, and the nonlinear dynamic model is developed finally.Vibration response of translational and tilted movement with damping is deduced based on multiscale method, and the formula of axial vibration response is developed using averaging method. The relationship between nonlinear vibration response and parameters of structure and controller of MSF is analyzed, and design considerations are suggested for the purpose of vibration suppression.Dynamic model developed using Lagrange equation is proposed. For ground and space application, coupled model of MSF with ground mounting platform and coupled model of MSFs with spacecraft are developed. The relationship between coupled vibration response and parameters of coupled structure and controller of MSF is analyzed, mutual disturbances between MSF and spacecraft are presented also. A notch filter with lead-lag correction is proposed for unbalance vibration suppression. Two neural network controllers are presented based on adaptive linear neuron and back propagation network, weights updating checking is proposed to ensure learning stability for adaptive linear neural network, and weights updating algorithm is proposed based on dynamic model of magnetic bearing-rotor system, online training and vibration suppression is verified. A simple dynamic model of MSF supported by flexible base is deduced, and a H∞controller is proposed based on mixed sensitive functions and linear matrix inequality (LMI) method, vibration suppression and platform adaptation is validated by numerical simulation.Two experimental systems are presented based on control platform using DSP and dSPACE. Vibration responses during flywheel acceleration and deceleration are presented to validate the study on nonlinear vibration response, online dynamic balance of MSF is performed based on dSPACE platform, and unbalance suppression is tested to validate the effectiveness of notch filter with lead-lag correction.In this dissertation, vibration mechanism is studied and methods for vibration suppression control are proposed. The findings partly verified by experiment have certain theoretical value and a high application value in MSF project.