scholarly journals Nonlinear Dynamics and Motion Bifurcations of the Rotor Active Magnetic Bearings System with a New Control Scheme and Rub-Impact Force

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1502
Author(s):  
Nasser Abul-Fadeel Saeed ◽  
Emad Mahrous ◽  
Emad Abouel Nasr ◽  
Jan Awrejcewicz
Keyword(s):  
Control Method ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Rotating Disc ◽  
Nonlinear Dynamical ◽  
Dynamic Friction Coefficient ◽  
Impact Forces ◽  
Control Scheme ◽  
The Impact ◽  
First Time

This article is dedicated to investigating the nonlinear dynamical behaviors of the 8-pole rotor active magnetic bearing system. The rub and impact forces between the rotating disc and the pole-legs are included in the studied model for the first time. A new control scheme based on modifying the 8-pole positions has been introduced. The proposed control methodology is designed such that four poles only are located in the horizontal and vertical directions (i.e., in +X,+Y,−X,−Y directions), while the other four poles are inserted in a way such that each pole makes 45° with two of the axes +X,+Y,−X,−Y. The control currents in the horizontal and vertical poles are suggested to be proportional to both the velocity and displacement of the rotor in the horizontal and vertical directions, respectively, while the control currents in the inclined poles are proposed to be dependent on the combination of both the displacement and velocity of the rotor in the horizontal and vertical directions. Accordingly, the whole-system mathematical model is derived. The derived discontinuous dynamical system is analyzed employing perturbation methods, Poincare maps, bifurcation diagrams, whirling orbits, and frequency spectrum. The obtained results demonstrated that the controller proportional control gain can play a significant role in changing the vibratory behaviors of the system, where the proposed control method can behave either as a cartesian control strategy or as a radial control one depending on the magnitude of the proportional gain. In addition, it is found that the rotor system can vibrate with periodic, periodic-n, quasiperiodic, or chaotic motion when the rub and/or impact forces occur. Moreover, it is reported for the first time that the rotor-AMB can oscillate symmetrically in X and Y directions either in full annular rub mode or quasiperiodic partial rub mode depending on the impact stiffness coefficient and the dynamic friction coefficient.

Isotropic Optimal Control of Active Magnetic Bearing System

1996 ◽  
Vol 118 (4) ◽  
pp. 721-726 ◽  
Author(s):  
Cheol-Soon Kim ◽  
Chong-Won Lee
Keyword(s):  
Optimal Control ◽  
System Analysis ◽  
Control Method ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Control Effort ◽  
Response Component ◽  
Unbalance Response ◽  
Control Scheme ◽  
Bearing System

As a new rotor control scheme, isotropic control of weakly anisotropic rotor bearing system in complex state space is proposed, which utilizes the concepts on the eigenstructure of the isotropic rotor system. Advantages of the scheme are that the controlled system always retains isotropic eigenstructure, leading to circular whirling due to unbalance and that it is efficient for control of unbalance response. And the system analysis and controller design becomes simple and yet comprehensive since the order of the matrices treated in the complex domain approach is half of that in the real approach. The control scheme is applied to a rigid rotor-active magnetic bearing system which is digitally controlled and the control performance is investigated experimentally in relation to unbalance response and control energy. It is found that the isotropic optimal control method, which essentially eliminates the backward unbalance response component, is more efficient than the conventional optimal control in that it gives smaller major whirl radius and yet it often requires less control effort.

scholarly journals The Impact Analysis of Beating Vibration for Active Magnetic Bearing

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 134104-134112 ◽  
Author(s):  
Hui Gao ◽  
Xianhai Meng ◽  
Kejun Qian
Keyword(s):  
Impact Analysis ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
The Impact

A Field Balancing Technique Based on Virtual Trial-Weights Method for a Magnetically Levitated Flexible Rotor

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Yingguang Wang ◽  
Jiancheng Fang ◽  
Shiqiang Zheng
Keyword(s):  
High Efficiency ◽  
Notch Filter ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
New Method ◽  
Mode Shapes ◽  
Flexible Rotor ◽  
Magnetically Levitated ◽  
Balancing Efficiency ◽  
The Impact

For a magnetically levitated flexible rotor (MLFR), the amount of residual imbalance not only generates undesired vibrations, but also results in excessive bending, which may cause it hit to the auxiliary bearings. Thus, balancing below the critical speed is essential for the MLFR to prevent the impact. This paper proposes a balancing method of high precision and high efficiency, basing on virtual trial-weights. First, to reduce the computed error of rotor's mode shapes, a synchronous notch filter is inserted into the active magnetic bearing (AMB) controller, achieving a free support status. Then, AMBs provide the rotor with the synchronous electromagnetic forces (SEFs) to simulate the trial-weights. The SEFs with the initial angles varying from 0 deg to 360 deg in the rotational frame system result in continuous changes in the MLFR's deflection. Last, correction masses are calculated according to the changes. Compared to the trail-weights method, the new method needs not test-runs, which improves the balancing efficiency. Compared to the no trail-weights method, the new method does not require a precise model of the rotor-bearing system, which is difficult to acquire in the real system. Experiment results show that the novel method can reduce the residual imbalance effectively and accurately.

scholarly journals Active Control for Multinode Unbalanced Vibration of Flexible Spindle Rotor System with Active Magnetic Bearing

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaoli Qiao ◽  
Guojun Hu
Keyword(s):  
High Speed ◽  
Control Method ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Active Magnetic Bearing ◽  
Influence Coefficient ◽  
Control Effect ◽  
High Speed Cutting ◽  
Influence Coefficient Method ◽  
Cutting Processes

The unbalanced vibration of the spindle rotor system in high-speed cutting processes not only seriously affects the surface quality of the machined products, but also greatly reduces the service life of the electric spindle. However, since the unbalanced vibration is often distributed on different node positions, the multinode unbalanced vibration greatly exacerbates the difficulty of vibration control. Based on the traditional influence coefficient method for controlling the vibration of a flexible rotor, the optimal influence coefficient control method with weights for multinode unbalanced vibration of flexible electric spindle rotors is proposed. The unbalanced vibration of all nodes on the whole spindle rotor is used as the control objective function to achieve optimal control. The simulation results show that the method has an obvious control effect on multinode unbalanced vibration.

Dynamic Analysis of Active Magnetic Bearing Rotor Dropping on Auto-eliminating Clearance Auxiliary Bearing Devices

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Chengtao Yu ◽  
Chaowu Jin ◽  
Xudong Yu ◽  
Longxiang Xu
Keyword(s):  
Dynamic Models ◽  
Ball Bearing ◽  
Experimental Studies ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Grease Lubrication ◽  
Successful Operation ◽  
Convex Shape ◽  
Auxiliary Bearing ◽  
The Impact

Auto-eliminating clearance auxiliary bearing devices (ACABD) can automatically eliminate the protective clearance between the ball bearing's outer race and the ACABD's supports, thus recenter the rotor when active magnetic bearing (AMB) system fails. This paper introduces the mechanical structure and working principles of the ACABD. When the rotor drops, numerical and experimental studies on the transient responses of the rotor and the ACABD's supports are also conducted as follows. First, we propose an equivalent clearance circle method to establish dynamic models of rotor dropping on the ACABD. Based on these models, the rotor dropping simulations are carried out to investigate the modes of lubrication and the ACABD's support shape's influences on the performance and execution time of clearance elimination. Second, various AMB rotor dropping tests are performed on our experimental setup with different ACABD supporting conditions. Indicated from the basically consistent simulation and experimental results, the correctness of the theoretical analysis and the successful operation of ACABD have been verified. Moreover, with the grease lubrication in the ball bearing and convex shape supports, the ACABD can eliminate the protective clearance within approximately 0.5 s upon the rotor drops and then sustain the rotor to operate stably around its original rotation center. Because of clearance elimination, the dramatic impact between the ball bearing and the supports is avoided and the impact forces among each part are effectively reduced. Meanwhile, the possibility of incurring full-clearance backward whirling motion is eliminated.

scholarly journals Study on Unbalanced Magnetic Pulling Analysis and Its Control Method for Primary Helium Circulator of High-Temperature Gas-Cooled Reactor

2019 ◽  
Author(s):  
Yangbo Zheng ◽  
Ni Mo ◽  
Zhe Sun ◽  
Yan Zhou ◽  
Zhengang Shi
Keyword(s):  
High Temperature ◽  
Control Method ◽  
Effective Means ◽  
Electromagnetic Levitation ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Control Effect ◽  
Significant Control ◽  
Double Frequency ◽  
High Temperature Gas

In addition to provide an extremely clean environment for primary loop of high-temperature gas-cooled reactor (HTR), the primary helium circulator (PHC) using electromagnetic levitation technology also provides an effective means for vibration control. Besides synchronous vibration produced by mass imbalance and sensor runout, double-frequency vibration produced by unbalanced magnetic pull (UMP) is serious in PHC engineering prototype (PHC-EP). In this paper, we firstly analyzed the mechanism of UMP and the multi-frequency vibration characteristics in combination with the PHC-EP. Then we put forward a distributed iterative learning control (ILC) algorithm and a parallel control scheme to suppress the periodic vibrations. Finally, we verified the methods by carrying out experimental researches on the active magnetic bearing (AMB) bench of PHC-EP. The results show that the methods put forward in this paper have significant control effect on the double-frequency vibration generated by UMP of the PHC-EP, and provide theoretical and practical references for the PHC safe operation in HTR.

scholarly journals Fixed-time sliding mode attitude control of a flexible spacecraft with rotating appendages connected by magnetic bearing

2022 ◽  
Vol 19 (3) ◽  
pp. 2286-2309
Author(s):  
Gaowang Zhang ◽  
◽  
Feng Wang ◽  
Jian Chen ◽  
Huayi Li
Keyword(s):  
Attitude Control ◽  
Control Method ◽  
Sliding Mode ◽  
Fixed Time ◽  
Magnetic Bearing ◽  
Flexible Spacecraft ◽  
Active Magnetic Bearing ◽  
Connected Components ◽  
Solar Panels ◽  
Satellite Platform

<abstract> <p>This study focuses on the attitude control of a flexible spacecraft comprising rotating appendages, magnetic bearings, and a satellite platform capable of carrying flexible solar panels. The kinematic and dynamic models of the spacecraft were established using Lagrange methods to describe the translation and rotation of the spacecraft system and its connected components. A simplified model of the dynamics of a five-degrees-of-freedom (DOF) active magnetic bearing was developed using the equivalent stiffness and damping methods based on the magnetic gap variations in the magnetic bearing. Next, a fixed-time sliding mode control method was proposed for each component of the spacecraft to adjust the magnetic gap of the active magnetic bearing, realize a stable rotation of the flexible solar panels, obtain a high inertia for the appendage of the spacecraft, and accurately control the attitude. Finally, the numerical simulation results of the proposed fixed-time control method were compared with those of the proportional-derivative control method to demonstrate the superiority and effectiveness of the proposed control law.</p> </abstract>

Aseismic Vibration Control of Flexible Rotors Using Active Magnetic Bearing

2001 ◽  
Vol 124 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Osami Matsushita ◽  
Toshio Imashima ◽  
Yoshitaka Hisanaga ◽  
Hiroki Okubo
Keyword(s):  
Seismic Waves ◽  
Control Method ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Flexible Rotor ◽  
Feed Forward Control ◽  
Kobe Earthquake ◽  
Flexible Rotors ◽  
Additional Control ◽  
Modal Model

The wide application of active magnetic bearing (AMB) requires an aseismic evaluation with respect to AMB rotor vibrations caused by actual earthquakes. A flexible rotor supported by AMB is selected for this purpose. A shaking simulation obtained using the quasi-modal model and the actual Kobe earthquake was completed. A corresponding test rotor was excited by seismic waves and the resulting vibration was measured for the vibration evaluation. In order to reduce the response severity against earthquakes, we propose an additional feed forward control method which is proportional to the signal detected by the accelerometers attached to the bearing housings. Since this additional control can cancel rotor vibration generated by the earthquakes, AMB rotor vibrations are successfully suppressed at a low level.

scholarly journals A novel iterative learning control method and control system design for active magnetic bearing rotor imbalance of primary helium circulator in high-temperature gas-cooled reactor

2020 ◽  
Vol 53 (3-4) ◽  
pp. 474-484
Author(s):  
Yangbo Zheng ◽  
Xingnan Liu ◽  
Jingjing Zhao ◽  
Ni Mo ◽  
Zhengang Shi
Keyword(s):  
Control System ◽  
High Temperature ◽  
Iterative Learning Control ◽  
Control Method ◽  
Learning Control ◽  
Magnetic Bearing ◽  
Iterative Learning ◽  
Active Magnetic Bearing ◽  
Rotor Imbalance ◽  
High Temperature Gas

As one of the key technologies of high-temperature gas-cooled reactor, primary helium circulator–equipped active magnetic bearing provides driving force for primary helium cooling system. However, repetitive periodic vibration produced by rotor imbalance may introduce risks to primary helium circulator (even for high-temperature gas-cooled reactors). First, this article analyzes a periodic component extraction algorithm which is widely used in active magnetic bearing rotor unbalance control methods and points out the problem that the periodic component extraction algorithm occupies numerous computing resources which cannot satisfy the real-time request of active magnetic bearing control system. Then, a novel iterative learning control algorithm based on the iteration before last iteration of system information (iterative learning control-2) and a plug-in parallel control mechanism based on the existing control system are put forward, meanwhile, an integrated independent distributed active magnetic bearing control system is designed to solve the problem. Finally, both the simulation and experiment are carried out, respectively. The corresponding results show that the control method and control system proposed in this article have significant suppression effect on the repetitive periodic vibration of the active magnetic bearing system without degrading the real-time requirement and can provide important technical support for the safe and stable operation of the primary helium circulator in high-temperature gas-cooled reactor.

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