Research On Control Strategy Of Single Dof Support System Of Magnetic-liquid Double Suspension Bearing

Magnetic-Liquid Double Suspension Bearing(MLDSB)includes liquid hydrostatic and magnetic Suspension supporting systems,and its bearing capacity and stiffness can be improved sharply.Meanwhile,the two supporting systems are all nonlinear systems,and are coupled with each other,and interfere with each other,which further aggravates the nonlinear characteristics of the MLDSB that seriously affects its operational reliability and stability.However the operating stability is the basis and premise of design and performance analysis of MLDSB.Therefore,the operation stability of MLDSB is analyzed,and controller design is studied in this paper.The main research work in this paper is as follows:(1)According to the mathematical modeling theory of Maxwell and static bearing,the mathematical model of MLDSB is established,it can provide the theoretical foundation for studying the operation stability and controller design of MLDSB.(2)The transfer function of the single-degree-of-freedom support system of MLDSB is established by the linearization process and Laplace transformation.And it is found that the system is inherently unstable.Therefore,the controller design is designed by root trajectory and frequency method and state feedback method.And the control precision and anti-interference ability of the designed controller are verified by the Matlab/Simulink software simulation.(3)Due to the MLDSB has strong characteristic of nonlinearity,so the controller design should be based on the nonlinear model of the system,and the specific control algorithm includes the PID,the simple nonlinear robustness controller is made by the precise feedback linearization method and closed-loop gain forming algorithm,and the adaptive sliding mode control algorithm.The control precision and anti-interference ability of the designed controller are verified by the Matlab/Simulink software simulation.(4)Aiming at the uncertainties such as the unmodeled dynamics and so on in the system of MLDSB,so the H_∞controller is designed by H_∞mixed sensitivity method.In the design process,some internal relations between the weighting function and the controller are proposed,and the good signal tracking and anti-interference ability of the H_∞controller is theoretically verified by Matlab/Simulink software simulation.Finally,considering the economics and control quality,the MLDSB system controller design is completed by Matlab/Simulink simulation and partial experiments,which provides a theoretical reference for the structural design and performance analysis of the MLDSB system.