In magnetic bearing-rotor systems,the bending mode vibration may be excited by the interface contact formed by bolt joints during rotor levitation,and the vibration frequency varies with rotation speed.To actively control bending mode vibration at any speed,the design method of a robust H∞ controller considering frequency uncertainty was proposed.Firstly,the dynamic model considering interface contact was established for numerical simulation,and the vibration frequency variation was obtained.Then,the rotor transfer function was reconstructed by frequency response fitting,and the variation range of vibration frequency obtained by simulation was introduced into the reconstructed transfer function by means of additive uncertainty.As a result,a controlled object model considering mode frequency uncertainty was obtained.Finally,based on the model,the robust H∞controller was designed by taking the robustness to parameter perturbations and external disturbance,closed-loop system stability,control voltage saturation,and other functions into account.The numerical simulation results show that the controller has the frequency response characteristic of wide band resistance at the mode frequency,which is able to suppress the bending mode vibration of the magnetic bearing-rotor system.After the robust H∞controller designed by this method is used,the bending mode vibration amplitude of the rotor is reduced by more than 90％.
关键词
主动磁悬浮轴承/界面接触/模态振动/鲁棒控制
Key words
active magnetic bearing/interface contact/mode vibration/robust control
维普
万方数据