Influence of Design Parameters on Static Bifurcation Behavior of Magnetic Liquid Double Suspension Bearing

Zhao, Jianhua; Wu, Xiaochen; Han, Fang; Ma, Xuchao; Yan, Weidong; Liang, Yingna; Gao, Dianrong; Du, Gonghuan

doi:10.1155/2021/6646235

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…The radial unit of MLDSB is composed a of step shaft, a magnetic guide sleeve, a supporting cavity, a magnetic pole, an inlet pipe, a shell, a coil, and an outlet, as shown in Figure 2. The regulation principle of MLDSB is shown as Figure 3 [2]. Due to its strong nonlinear characteristics and complicated damping characteristics, it features mutual coupling between its two supporting systems, and Hopf bifurcation phenomenon occurs easily; consequently, the reliability and operational stability of MLDSB are reduced.…”

Section: Introductionmentioning

confidence: 99%

Influence of Coil Current and Oil Film Thickness on Hopf Bifurcation of MLDSB

et al. 2022

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Magnetic-liquid double-suspension bearing (MLDSB) is composed of an electromagnetic supporting system and a hydrostatic supporting system. Due to its greater supporting capacity and stiffness, it is appropriate for middle-speed applications, overloading, and frequent starting. However, because it contains two sets of systems, its structure and rotor support system are more complex. It contains strong nonlinear links. When the parameters of the system change, the bearing rotor may feature Hopf bifurcation, resulting in system flutter and reducing the operational stability of the magnetic fluid double-suspension bearing rotor, which has become one of the key problems restricting its development and application. As key parameters of MLDSB, the coil current and oil film thickness exert a major impact on Hopf bifurcation. Therefore, the mathematical model of MLDSB is established in this paper, and the border and direction of Hopf bifurcation, period, and amplitude of limit cycle are analyzed. The calculation, simulation, and experimental results show that when the coil current and oil film thickness of the bearing system are greater than the boundary value of the Hopf bifurcation, Hopf bifurcation will occur, resulting in the vibration of the bearing rotor and affecting the stability of the system. In addition, when analyzing the combined effects of coil current and oil film thickness on the Hopf bifurcation of the system, it was found that the boundary value of Hopf bifurcation in the system is reduced compared with when it is are affected solely due to the coupling of the two parameters. The period, amplitude and vibration speed of limit cycle increase with increases in the coil current and oil film thickness. Hopf bifurcation experiment was conducted on MLDSB testing system. The results show that Hopf bifurcation does not occur when i0 < 0.5 A, the bearing rotor operates stably in the balanced position, i0 > 1.0 A, Hopf bifurcation occurs in the system, and the bearing rotor vibrates with equal amplitude, which reduces the stability of operation. The research in this paper can provide a theoretical reference for the Hopf bifurcation analysis of MLDSB.

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Section: Introductionmentioning

confidence: 99%

Influence of Coil Current and Oil Film Thickness on Hopf Bifurcation of MLDSB

et al. 2022

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Investigation of end effect in integrated permanent magnetic damper for cylinder block–valve plate pair in axial piston pump

Boran

Jiang

2022

AIP Advances

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The present work develops an integrated permanent magnetic damper (IPMD) to apply magnetic torque on a cylinder block, which makes it possible to suppress eccentric wear of the cylinder block–valve plate pair in an axial piston pump. Then, the structure and working principle of the IPMD are described. According to the relationship between the axial and the radial magnetic pole gap, the corresponding end flux tube models are established. Based on the principle of micro-displacement, the axial magnetic force and torque output by IPMD are derived. After separating from the relevant structures inside the pump, to ensure the effectiveness of the results, the test method of IPMD independent of the axial piston pump is provided. To make a more comprehensive analysis of the magnetic bearing characteristics, the prototype of IPMD is manufactured and tested. The influence of the end effect of IPMD on the residual hydraulic torque under different discharge pressures is studied. The results verified the correctness of the theoretical analysis, which have important guiding significance to improve the reliability of the cylinder block–valve plate pair in the axial piston pump.

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Decoupling control of radial 4 degree of freedom system of magnetic-liquid double suspension bearing based on generalized extended state observer

Chai

Shi

Chen

et al. 2023

Review of Scientific Instruments

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As the novel suspension bearing, Magnetic-Liquid Double Suspension Bearing (MLDSB) is mainly supported by magnetic suspension and supplemented by a liquid hydrostatic bearing. Due to its great bearing capacity and stiffness, rapid response, great active control, and so on, MLDSB is suitable for medium speed heavy loads and has a large carrying capacity and high operating stability. In addition, the radial inertia coupling and gyroscopic coupling between radial 4-DOF control channels can reduce control precision, operation stability, and reliability of MLDSB. Therefore, a mathematical model of radial 4-DOF rotor-dynamics of MLDSB is established in this paper, and the inherent coupling mechanism is explored. Taking inertial coupling, gyroscopic coupling, and external disturbance loads as lumped disturbances, a decoupled controller based on Generalized Extended State Observer (GESO) is established. The influence of the GESO controller on the decoupling and control performance of radial 4-DOF control channels is simulated. The results indicate that the decoupling effect of the GESO controller is great. Under the action of step signal, the steady displacement, maximum displacement, adjustment time, and peak time of the rotor after decoupling are all reduced, among which the steady displacement and maximum displacement are the most obvious. Under the sinusoidal signal, the steady displacement and maximum displacement are reduced by 90%, which can effectively avoid the “gap-impact” fault. Under the pulse signal, the steady displacement, maximum displacement, adjustment time, and peak time are all reduced, among which the maximum displacement is the most obvious. The research in this paper can provide a theoretical reference for the stable support and decoupling control of MLDSB.

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Influence of Design Parameters on Static Bifurcation Behavior of Magnetic Liquid Double Suspension Bearing

Cited by 3 publications

References 8 publications

Influence of Coil Current and Oil Film Thickness on Hopf Bifurcation of MLDSB

Influence of Coil Current and Oil Film Thickness on Hopf Bifurcation of MLDSB

Investigation of end effect in integrated permanent magnetic damper for cylinder block–valve plate pair in axial piston pump

Decoupling control of radial 4 degree of freedom system of magnetic-liquid double suspension bearing based on generalized extended state observer

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