| Active magnetic bearing(AMB)has advantages of contactless,long life span,frictionless,the supporting characteristic is adjustable,etc.,which make AMB has broad application prospects in rotating machinery.As a typical multi-input/multioutput(MIMO)and strong coupling system,the design of controller will affect the performance of the system.This thesis studies the decoupling control and displacement vibration control of magnetic suspension rotor system.The dynamic model of magnetic suspension rigid-rotor system is established.Compared with the modal analysis results acquired by FEM software,the relationship between control parameters and equivalent supporting stiffness & damping is verified.The dynamic model of magnetic suspension flexible-rotor system is established based on finite element theory.The differences between natural frequencies solved by magnetic suspension rigid-rotor and flexible-rotor models under different equivalent supporting stiffness are compared and the reasons lead to this phenomenon are analyzed.The vibration transfer characteristics of magnetic bearing under different supporting stiffness and damping are studied by using FEM simulation.The decoupling controllers of magnetic suspension rigid/flexible rotor system are designed based on inverse system theory.The differences between decoupling control system and the original system are compared and analyzed from the perspective of frequency domain.The simulation model of the decoupling control system and the original system are built in SIMULINK.For original and decoupling control system of magnetic suspension rigid rotor/flexible rotor model,the characteristics of the response under different excitations are discussed and the causes are analyzed through frequency domain analysis,the correctness of decoupling is verified.Based on the decoupling magnetic suspension rigid-rotor system,unbalance compensation is realized by applying adaptive iterative search algorithm.The vibration amplitude calculation module is designed and the correctness of the module is verified.The basic method of obtaining compensation current through adaptive iterative search is introduced.The simulation model is built in SIMULINK and the effectiveness of the algorithm is verified.White noise signal is applied to each control channel to prove the anti-interference ability of the algorithm.The compensation effect under singlechannel disturbance is compared when decoupling control and decentralized PID control are used.Based on the magnetic suspension rotor experiment platform,the decoupling control experiment of the magnetic suspension rigid-rotor system is carried out.The linear state feedback decoupling control and decentralized PID control are applied to the system separately,the effect of decoupling control is verified through comparing the displacement response of rotor under the circumstances that rotor is stably levitated and impulse excitation is applied. |
