Engineering › Control and Systems Engineering

Magnetic Bearings and Levitation Dynamics

Works Count: 40466

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Description

This cluster of papers focuses on the dynamics, control, and applications of magnetic levitation systems, including maglev trains, bearingless motors, active magnetic bearings, spacecraft attitude control using control moment gyros, vibration analysis of rotor systems, and fault diagnosis in rotating machinery.

Keywords

Magnetic Levitation; Control Systems; Active Magnetic Bearings; Rotor Dynamics; Nonlinear Control; Maglev Transportation; Vibration Analysis; Bearingless Motors; Spacecraft Attitude Control; Fault Diagnosis

Linear Synchronous Motors

1999-09-29

Jacek F. Gieras , Zbigniew J. Piech

Considered to be the first book devoted to the subject, Linear Synchronous Motors: Transportation and Automation Systems, Second Edition evaluates the state of the art, demonstrating the technological innovations that … Considered to be the first book devoted to the subject, Linear Synchronous Motors: Transportation and Automation Systems, Second Edition evaluates the state of the art, demonstrating the technological innovations that are improving the design, construction, and performance of modern control systems. This new edition not only illustrates the development of linear synchronous motor drives, but it also discusses useful techniques for selecting a motor that will meet the specific requirements of linear electrical drives. New Features for the Second Edition: Several updated and expanded sections, as well as two new chapters on FEM Even more numerical examples, calculations, and mathematical models Broadened target audience that includes researchers, scientists, students, and more Evaluating trends and practical techniques for achieving optimal system performance, the authors showcase ready-to-implement solutions for common roadblocks in this process. The book presents fundamental equations and calculations used to determine and evaluate system operation, efficiency, and reliability, with an exploration of modern computer-aided design of linear synchronous motors, including the finite element approach. It covers topics such as linear sensors and stepping motors, magnetic levitation systems, elevators, and factory automation systems. It also features case studies on flat PM, tubular PM, air-cored, and hybrid linear synchronous motors, as well as 3D finite element method analysis of tubular linear reluctance motors, and linear oscillatory actuators. With such an exceptional presentation of practical tools and conceptual illustrations, this volume is an especially powerful resource. It will benefit readers from all walks by providing numerical examples, models, guidelines, and diagrams to help develop a clear understanding of linear synchronous motor operations, characteristics, and much more.

Analytical Mechanics Of Space Systems

2003-01-01

Hanspeter Schaub , John L. Junkins

Analytical Mechanics of Space Systems, Third Edition provides a comprehensive treatment of dynamics of space systems, starting with the fundamentals and covering topics from basic kinematics and dynamics to more … Analytical Mechanics of Space Systems, Third Edition provides a comprehensive treatment of dynamics of space systems, starting with the fundamentals and covering topics from basic kinematics and dynamics to more advanced celestial mechanics. The reader is guided through the various derivations and proofs in a tutorial way and is led to understand the principles underlying the equations at issue, and shown how to apply them to various dynamical systems. Part I covers analytical treatment of topics such as basic dynamic principles up to advanced energy concepts. Special attention is paid to the use of rotating reference frames that often occur in aerospace systems. Part II covers basic celestial mechanics, treating the two-body problem, restricted three-body problem, gravity field modeling, perturbation methods, spacecraft formation flying, and orbit transfers. MATLAB[registered], Mathematica[registered], Python and C-Code toolboxes are provided for the rigid body kinematics routines discussed in chapter 3, and the basic orbital 2-body orbital mechanics routines discussed in chapter 9. The third edition streamlines the presentation of material by adding additional examples, homework problems, and illustrations. It includes expanded discussion on: Numerically integrating MRPs and using heading measurements and evaluating a three-dimensional orientation; Numerically integrating the complex VSCMG differential equations of motion; The Lyapunov function and stability definitions; implementing a rate-based attitude servo control solution, and integrating an integral feedback component with a reaction wheel based attitude control, featuring new examples; developing acceleration-based VSCMG steering laws for three-axis attitude control developments; and, new Appendix I describes how to implement Kalman-Filter estimating MRP coordinates in a non-singular fashion.

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Magnetic Bearings and Bearingless Drives

2005-01-01

Akira Chibá , Tadashi Fukao , Osamu Ichikawa +3 more

The S-rotor and its applications

1931-01-01

S. J. Savonius

Rotordynamics prediction in engineering

1991-06-01

A. G. Parkinson

Vibration: fundamentals and practice

2000-06-01

Clarence W. de Silva

VIBRATION ENGINEERING Introduction Study of Vibration Application Areas History of Vibration Organization of the Book Problems TIME RESPONSE Introduction Undamped Oscillator Heavy Springs Oscillations in Fluid Systems Damped Simple Oscillator … VIBRATION ENGINEERING Introduction Study of Vibration Application Areas History of Vibration Organization of the Book Problems TIME RESPONSE Introduction Undamped Oscillator Heavy Springs Oscillations in Fluid Systems Damped Simple Oscillator Forced Response Problems FREQUENCY RESPONSE Introduction Response to Harmonic Excitations Transform Techniques Mechanical Impedance Approach Transmissibility Functions Receptance Method Problems VIBRATION SIGNAL ANALYSIS Introduction Frequency Spectrum Signal Types Fourier Analysis Random Vibration Analysis Other Topics of Signal Analysis Order Analysis Machine Monitoring and Fault Diagnosis Problems MODAL ANALYSIS Introduction Degrees of Freedom and Independent Coordinates System Representation Modal Vibrations Orthogonality of Natural Modes Static Modes and Rigid Body Modes Other Modal Formulations Forced Vibration Damped Systems State-Space Approach Problems DISTRIBUTED-PARAMETER SYSTEMS Introduction Transverse Vibration of Cables Longitudinal Vibrations of Rods Torsional Vibration of Shafts Flexural Vibration of Beams Damped Continuous Systems Vibration of Membranes and Plates Problems VIBRATION DAMPING Introduction Types of Damping Representation of Damping in Vibration Analysis Measurement of Damping Interface Damping Problems VIBRATION INSTRUMENTATION Introduction Vibration Exciters Control System Performance Specification Motion Sensors and Transducers Torque, Force, and Other Sensors Problems SIGNAL CONDITIONING AND MODIFICATION Introduction Amplifiers Analog Filters Modulators and Demodulators Analog-Digital Conversion Bridge Circuits Linearizing Devices Miscellaneous Signal Modification Circuitry Signal Analyzers and Display Devices Problems VIBRATION TESTING AND HUMAN RESPONSE Introduction Representation of a Vibration Environment Pre-Test Procedures Testing Procedures Some Practical Information Vibration Excitations on Humans Human Response to Vibration Regulation of Human Vibration Problems EXPERIMENTAL MODAL ANALYSIS Introduction Frequency Domain Formulation Experimental Model Development Curve Fitting of Transfer Functions Laboratory Experiments Commercial EMA Systems Problems VIBRATION DESIGN AND CONTROL Introduction Specification of Vibration Limits Vibration Isolation Balancing of Rotating Machinery Balancing of Reciprocating Machines Whirling of Shafts Design through Modal Testing Passive Control of Vibration Active Control of Vibration Control of Beam Vibrations Problems APPENDIX A: DYNAMIC MODELS AND ANALOGIES Model Development Analogies Mechanical Elements Electrical Elements Thermal Elements Fluid Elements State-Space Models Response Analysis and Simulation APPENDIX B: NEWTONIAN AND LAGRANGIAN MECHANICS Vector Kinematics Newtonian (Vector) Mechanics Lagrangian Mechanics APPENDIX C: REVIEW OF LINEAR ALGEBRA Vectors and Matrices Vector-Matrix Algebra Matrix Inverse Vector Spaces Determinants System of Linear Equations Quadratic Forms Matrix Eigenvalue Problem Matrix Transformations Matrix Exponential APPENDIX D: LAPLACE TRANSFORM Introduction Laplace Transform Response Analysis Transfer Function APPENDIX E: DIGITAL FOURIER ANALYSIS AND FFT Unification of the Three Fourier Transform Types Fast Fourier Transform (FFT) Discrete Correlation and Convolution Digital Fourier Analysis Procedures APPENDIX F: SOFTWARE TOOLS SIMULINK MATLAB Control Systems Toolbox LabVIEW APPENDIX G: RELIABILITY CONSIDERATIONS FOR MULTI-COMPONENT UNITS Failure Analysis Bayes' Theorem INDEX

Tribology and Mechanics of Magnetic Storage Devices

1996-01-01

Bharat Bhushan

Analysis of the Response of a Multi-Rotor-Bearing System Containing a Transverse Crack in a Rotor

1984-01-01

I. W. Mayes , Will Davies

The paper describes work that has been carried out into the flexural vibrational behavior of a rotor mounted on several bearings and containing a transverse crack. A method of solving … The paper describes work that has been carried out into the flexural vibrational behavior of a rotor mounted on several bearings and containing a transverse crack. A method of solving the equations of motion of a general system is presented. This method utilizes standard rotor dynamics computer programs and enables calculations on large systems to be made on a routine basis. An approximate method of estimating the reduction of a section diameter required to model a crack for use in beam theory based on finite elements is given which is simple to use and gives acceptable results in practice. The application of the methods to some large turbogenerators is described.

Speed-Sensorless Vector Control of a Bearingless Induction Motor With Artificial Neural Network Inverse Speed Observer

2012-06-12

Xiaodong Sun , Long Chen , Zebin Yang +1 more

To effectively reject the influence of speed detection on system stability and precision for a bearingless induction motor, this paper proposes a novel speed observation scheme using artificial neural network … To effectively reject the influence of speed detection on system stability and precision for a bearingless induction motor, this paper proposes a novel speed observation scheme using artificial neural network (ANN) inverse method. The inherent subsystem consisting of speed and torque winding currents is modeled, and then its inversion is implemented by the ANN. The speed is successfully observed via cascading the original subsystem with its inversion. The observed speed is fed back in the speed control loop, and thus, the speed-sensorless vector drive is realized. The effectiveness of this proposed strategy has been demonstrated by experimental results.

A Finite Rotating Shaft Element Using Timoshenko Beam Theory

1980-10-01

H. D. Nelson

The use of finite elements for simulation of rotor systems has received considerable attention within the last few years. The published works have included the study of the effects of … The use of finite elements for simulation of rotor systems has received considerable attention within the last few years. The published works have included the study of the effects of rotatory inertia, gyroscopic moments, axial load, and internal damping; but have not included shear deformation or axial torque effects. This paper generalizes the previous works by utilizing Timoshenko beam theory for establishing the shape functions and, thereby including transverse shear effects. Internal damping is not included but the extension is straight forward. Comparison is made of the finite element analysis with classical dosed form Timoshenko beam theory analysis for nonrotating and rotating shafts.

ANALYSIS OF COMPUTED ORDER TRACKING

1997-03-01

K.R. Fyfe , E.D.S. Munck

The first man-loading high temperature superconducting Maglev test vehicle in the world

2002-10-01

Jiasu Wang , Suyu Wang , Youwen Zeng +7 more

A Survey Of The Dynamic Behaviour Of A Simple Rotating Shaft With A Transverse Crack

1993-01-01

Robert Gasch

Dynamics of Rotating Systems

2005-01-01

Giancarlo Genta

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THE HARMONIC BALANCE METHOD WITH ARC-LENGTH CONTINUATION IN ROTOR/STATOR CONTACT PROBLEMS

2001-03-01

G. VON GROLL , D. J. Ewins

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Third‐generation Blood Pumps With Mechanical Noncontact Magnetic Bearings

2006-05-01

Hideo Hoshi , Tadahiko Shinshi , Setsuo Takatani

Abstract: This article reviews third‐generation blood pumps, focusing on the magnetic‐levitation (maglev) system. The maglev system can be categorized into three types: (i) external motor‐driven system, (ii) direct‐drive motor‐driven system, … Abstract: This article reviews third‐generation blood pumps, focusing on the magnetic‐levitation (maglev) system. The maglev system can be categorized into three types: (i) external motor‐driven system, (ii) direct‐drive motor‐driven system, and (iii) self‐bearing or bearingless motor system. In the external motor‐driven system, Terumo (Ann Arbor, MI, U.S.A.) DuraHeart is an example where the impeller is levitated in the axial or z ‐direction. The disadvantage of this system is the mechanical wear in the mechanical bearings of the external motor. In the second system, the impeller is made into the rotor of the motor, and the magnetic flux, through the external stator, rotates the impeller, while the impeller levitation is maintained through another electromagnetic system. The Berlin Heart (Berlin, Germany) INCOR is the best example of this principle where one‐axis control combination with hydrodynamic force achieves high performance. In the third system, the stator core is shared by the levitation and drive coil to make it as if the bearing does not exist. Levitronix CentriMag (Zürich, Switzerland), which appeared recently, employs this concept to achieve stable and safe operation of the extracorporeal system that can last for a duration of 14 days. Experimental systems including HeartMate III (Thoratec, Woburn, MA, U.S.A.), HeartQuest (WorldHeart, Ottawa, ON, Canada), MagneVAD (Gold Medical Technologies, Valhalla, NY, U.S.A.), MiTiHeart (MiTi Heart, Albany, NY, U.S.A.), Ibaraki University’s Heart (Hitachi, Japan) and Tokyo Medical and Dental University/Tokyo Institute of Technology’s disposable and implantable maglev blood pumps are also reviewed. In reference to second‐generation blood pumps, such as the Jarvik 2000 (Jarvik Heart, New York, NY, U.S.A.), which is showing remarkable achievement, a question is raised whether a complicated system such as the maglev system is really needed. We should pay careful attention to future clinical outcomes of the ongoing clinical trials of the second‐generation devices before making any further remarks. What is best for patients is the best for everyone. We should not waste any efforts unless they are actually needed to improve the quality of life of heart‐failure patients.

An Element Independent Corotational Procedure for the Treatment of Large Rotations

1986-05-01

C. Rankin , F. A. Brogan

A new corotational procedure is developed which enables existing finite element formulations to be used in problems that contain arbitrarily large rotations. Through the use of a nonsingular large rotation … A new corotational procedure is developed which enables existing finite element formulations to be used in problems that contain arbitrarily large rotations. Through the use of a nonsingular large rotation vector, the contribution of the rigid body motion of the element to the total displacement field is removed before element computations are performed, with the result that almost any element can be easily upgraded to handle large rotations. This paper contains a derivation of the theory, an outline of the implementation into the STAGS code, and a demonstration of performance for problems involving large rotations and moderate strains.

Sliding mode and classical controllers in magnetic levitation systems

1993-02-01

Dong‐il Cho , Yoshihito Kato , Darin R. Spilman

An experimental comparison is made between a sliding-mode controller and a classical controller for stabilizing and commanding a magnetic levitation system. The sliding-mode method can be applied to a nonlinear … An experimental comparison is made between a sliding-mode controller and a classical controller for stabilizing and commanding a magnetic levitation system. The sliding-mode method can be applied to a nonlinear system in the global sense, and the issues of performance and robustness to modeling uncertainties and disturbances can be directly incorporated in the design as tradeoff parameters.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Vibration Analysis Of A Motor-Flexible Coupling-Rotor System Subject To Misalignment And Unbalance, Part I: Theoretical Model And Analysis

1994-10-01

Ming‐Xing Xu , R. D. Marangoni

Real-Time PID Control Strategy for Maglev Transportation System via Particle Swarm Optimization

2010-03-24

Rong‐Jong Wai , Jeng-Dao Lee , Kun-Lun Chuang

This paper focuses on the design of a real-time particle-swarm-optimization-based proportional-integral-differential (PSO-PID) control scheme for the levitated balancing and propulsive positioning of a magnetic-levitation (maglev) transportation system. The dynamic model … This paper focuses on the design of a real-time particle-swarm-optimization-based proportional-integral-differential (PSO-PID) control scheme for the levitated balancing and propulsive positioning of a magnetic-levitation (maglev) transportation system. The dynamic model of a maglev transportation system, including levitated electromagnets and a propulsive linear induction motor based on the concepts of mechanical geometry and motion dynamics, is first constructed. The control objective is to design a real-time PID control methodology via PSO gain selections and to directly ensure the stability of the controlled system without the requirement of strict constraints, detailed system information, and auxiliary compensated controllers despite the existence of uncertainties. The effectiveness of the proposed PSO-PID control scheme for the maglev transportation system is verified by numerical simulations and experimental results, and its superiority is indicated in comparison with PSO-PID in previous literature and conventional sliding-mode (SM) control strategies. With the proposed PSO-PID control scheme, the controlled maglev transportation system possesses the advantages of favorable control performance without chattering phenomena in SM control and robustness to uncertainties superior to fixed-gain PSO-PID control.

NUMERICAL CALCULATION OF THE FORMULA OF REDUCTION TO THE MAGNETIC POLE

1964-02-01

В. Л. Баранов , Henri Naudy

Some important aspects of the principle of the reduction to the pole are examined first. Secondly, a numerical calculation method is presented, followed by two examples, one theoretical, the other … Some important aspects of the principle of the reduction to the pole are examined first. Secondly, a numerical calculation method is presented, followed by two examples, one theoretical, the other practical.

Singularity Robust Steering Logic for Redundant Single-Gimbal Control Moment Gyros

2001-09-01

Bong Wie , D. Bailey , Christopher Heiberg

In this paper we investigate a problem inherent in a system of redundant single-gimbal control moment gyros (CMGs). In particular, we present a simple yet effective way of passing through, … In this paper we investigate a problem inherent in a system of redundant single-gimbal control moment gyros (CMGs). In particular, we present a simple yet effective way of passing through, and also escaping from, any internal singularities. The proposed approach is based on the so-called singularity robust inverse, but it utilizes a nondiagonal weighting matrix in the mixed, two-norm and weighted least-squares minimization problem. The proposed steering logic effectively generates deterministic dither signals when the CMG system becomes near singular. Because the proposed CMG steering logic is based on the simple minimum two-norm, pseudoinverse solution, it does not explicitly avoid encounters but it rather approaches and rapidly transits unavoidable singularities whenever needed. However, the proposed steering logic is not intended for special missions in which prescribed attitude trajectories are to be exactly tracked in the presence of internal singularities.

Robust Nonsingular Terminal Sliding-Mode Control for Nonlinear Magnetic Bearing System

2010-06-16

Syuan‐Yi Chen , Faa‐Jeng Lin

This study presents a robust nonsingular terminal sliding-mode control (RNTSMC) system to achieve finite time tracking control (FTTC) for the rotor position in the axial direction of a nonlinear thrust … This study presents a robust nonsingular terminal sliding-mode control (RNTSMC) system to achieve finite time tracking control (FTTC) for the rotor position in the axial direction of a nonlinear thrust active magnetic bearing (TAMB) system. Compared with conventional sliding-mode control (SMC) with linear sliding surface, terminal sliding-mode control (TSMC) with nonlinear terminal sliding surface provides faster, finite time convergence, and higher control precision. In this study, first, the operating principles and dynamic model of the TAMB system using a linearized electromagnetic force model are introduced. Then, the TSMC system is designed for the TAMB to achieve FTTC. Moreover, in order to overcome the singularity problem of the TSMC, a nonsingular terminal sliding-mode control (NTSMC) system is proposed. Furthermore, since the control characteristics of the TAMB are highly nonlinear and time-varying, the RNTSMC system with a recurrent Hermite neural network (RHNN) uncertainty estimator is proposed to improve the control performance and increase the robustness of the TAMB control system. Using the proposed RNTSMC system, the bound of the lumped uncertainty of the TAMB is not required to be known in advance. Finally, some experimental results for the tracking of various reference trajectories demonstrate the validity of the proposed RNTSMC for practical TAMB applications.

Handbook of rotordynamics

1992-05-01

Fredric F. Ehrich

Keywords: rotor ; vibration ; rotation ; dynamique Reference Record created on 2005-11-18, modified on 2016-08-08 Keywords: rotor ; vibration ; rotation ; dynamique Reference Record created on 2005-11-18, modified on 2016-08-08

Active Electromagnetic Suspension System for Improved Vehicle Dynamics

2009-12-21

B. L. J. Gysen , Johannes Paulides , J.L.G. Janssen +1 more

This paper offers motivations for an electromagnetic active suspension system that provides both additional stability and maneuverability by performing active roll and pitch control during cornering and braking, as well … This paper offers motivations for an electromagnetic active suspension system that provides both additional stability and maneuverability by performing active roll and pitch control during cornering and braking, as well as eliminating road irregularities, hence increasing both vehicle and passenger safety and drive comfort.Various technologies are compared with the proposed electromagnetic suspension system that uses a tubular permanent-magnet actuator (TPMA) with a passive spring.Based on on-road measurements and results from the literature, several specifications for the design of an electromagnetic suspension system are derived.The measured on-road movement of the passive suspension system is reproduced by electromagnetic actuation on a quarter car setup, proving the dynamic capabilities of an electromagnetic suspension system.

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Efficient numerical treatment of periodic systems with application to stability problems

1977-01-01

Peretz P. Friedmann , C. E. Hammond , Tze‐Hsin Woo

Abstract Two efficient numerical methods for dealing with the stability of linear periodic systems are presented. Both methods combine the use of multivariable Floquet–Liapunov theory with an efficient numerical scheme … Abstract Two efficient numerical methods for dealing with the stability of linear periodic systems are presented. Both methods combine the use of multivariable Floquet–Liapunov theory with an efficient numerical scheme for computing the transition matrix at the end of one period. The numerical properties of these methods are illustrated by applying them to the simple parametric excitation problem of a fixed end column. The practical value of these methods is shown by applying them to some helicopter rotor blade aeroelastic and structural dynamics problems. It is concluded that these methods are numerically efficient, general and practical for dealing with the stability of large periodic systems.

Georg Duffing, Ingenieur: Erzwungene Schwingungen bei veränderlicher Eigenfrequenz und ihre technische Bedeutung. Sammlung Vieweg. Heft 41/42, Braunschweig 1918. VI+134 S

1921-01-01

Hamel

Es bestclit im wcscntliclten ails einrr P i I o t schen Rijhre: dereu Anzeigr clckti-iscli nnch dCni Scliiffsinnern iibcrtrngeii jvird Es bestclit im wcscntliclten ails einrr P i I o t schen Rijhre: dereu Anzeigr clckti-iscli nnch dCni Scliiffsinnern iibcrtrngeii jvird

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Posicast Control of Damped Oscillatory Systems

1957-01-01

Otto M. Smith

A novel method is presented for producing dead-bea response in a lightly-damped oscillatory feedback system. Complete transient response times of the order of a fraction of the natural oscillatory period … A novel method is presented for producing dead-bea response in a lightly-damped oscillatory feedback system. Complete transient response times of the order of a fraction of the natural oscillatory period can be obtained. Excellent waveshape reproduction is achieved through a linear phase lag with frequency. The method consists of exciting several transient oscillations, at closely spaced times, with magnitudes and phases so adjusted that the resultant sum of the transient oscillation phasors is zero. The steady-state output is the arithmetic sum of the excitation magnitudes. When a step input transient is divided into two spaced excitations, one-half cycle response is obtainable. When the input transient is divided into three excitations, one-fourth period or faster transient times are realizable, depending upon the available dynamic range or signal-to-noise ratio. The principle of design is to adjust a system to the maximum possible resonant frequency, independent of the damping factor, but stable, and then to apply the Posicast control to completely remove the oscillatory component in the output. In an electrical feedback control system, the additional hardware consists of one or two artificial transmission lines.

Admittance space stability analysis of power electronic systems

2000-01-01

Scott D. Sudhoff , Steven F. Glover , Peter Lamm +2 more

Power electronics based power distribution systems (PEDSs) are becoming increasingly common, particularly in marine and aerospace applications. Stability analysis of this class of systems is crucial due to the potential … Power electronics based power distribution systems (PEDSs) are becoming increasingly common, particularly in marine and aerospace applications. Stability analysis of this class of systems is crucial due to the potential for negative impedance instability. Existing techniques of stability analysis introduce artificial conservativeness, are sensitive to component grouping, and at the same time do not explicitly address uncertainties and variations in operating point. A new stability criterion, which reduces artificial conservativeness and is also insensitive to component grouping is described. In addition, a means of readily establishing design specifications from an arbitrary stability criterion which specifically includes a provision to incorporate uncertainty, parameter variation, and nonlinearities is set forth. The method is presented in the context of a hardware test system and is experimentally validated.

Modeling and nonlinear control of magnetic levitation systems

2001-01-01

Ahmed El Hajjaji , Mustapha Ouladsine

In this paper, the authors propose a nonlinear model for magnetic levitation systems which is validated with experimental measurements. Using this model, a nonlinear control law based on differential geometry … In this paper, the authors propose a nonlinear model for magnetic levitation systems which is validated with experimental measurements. Using this model, a nonlinear control law based on differential geometry is firstly synthesized. Then, its real-time implementation is developed. In order to highlight the performance of the proposed control law, experimental results are given.

Review of maglev train technologies

2006-06-28

Hyung-Woo Lee , Ki‐Chan Kim , Ju Lee

This paper reviews and summarizes Maglev train technologies from an electrical engineering point of view and assimilates the results of works over the past three decades carried out all over … This paper reviews and summarizes Maglev train technologies from an electrical engineering point of view and assimilates the results of works over the past three decades carried out all over the world. Many researches and developments concerning the Maglev train have been accomplished; however, they are not always easy to understand. The purpose of this paper is to make the Maglev train technologies clear at a glance. Included are general understandings, technologies, and worldwide practical projects. Further research needs are also addressed.

Unbalance compensation using generalized notch filters in the multivariable feedback of magnetic bearings

1996-01-01

R. Herzog , Ph. Bühler , Conrad Gähler +1 more

Unbalance of magnetically levitated rotors causes undesirable synchronous vibrations which may lead to saturation of the magnetic actuator. To avoid this problem we propose a generalized narrow-band notch filter which … Unbalance of magnetically levitated rotors causes undesirable synchronous vibrations which may lead to saturation of the magnetic actuator. To avoid this problem we propose a generalized narrow-band notch filter which is inserted into the multivariable feedback without destabilizing the closed loop. The parameters of the generalized notch filter strongly depend on the inverse sensitivity matrix evaluated at rotational speed. This matrix is easily measured a priori and stored in a look-up table. It is shown that a decentralized notch is feasible for weakly gyroscopic rotors. The proposed notch filter approach has advantages in terms of run-time complexity and analytical verification of closed-loop stability. Results from the implementation of the proposed unbalance compensation in industrial magnetic bearing systems are included.

High-precision magnetic levitation stage for photolithography

1998-04-01

Won-jong Kim , David L. Trumper

Vector analysis and control of advanced static VAR compensators

1993-01-01

C. Schauder , Hrishikesh Mehta

The advanced static VAR compensator (now widely known as the static condenser or STATCON) uses a high power self-commutating inverter to draw reactive current from a transmission line. Two fundamentally … The advanced static VAR compensator (now widely known as the static condenser or STATCON) uses a high power self-commutating inverter to draw reactive current from a transmission line. Two fundamentally different types of invertor can be used for this purpose; one providing control of output voltage magnitude and phase angle, and the other having only phase angle control. For each of these types, the governing equations are derived, and frequency domain analysis is used to obtain the relevant transfer functions for control system synthesis. Further analysis is provided to determine the response of the STATCON to negative sequence and harmonic voltage components on the transmission line. The results are illustrated with measured wave forms obtained from a scaled analogue model of an 80 MVAR STATCON.

Control Algorithms of Magnetic Suspension Systems Based on the Improved Double Exponential Reaching Law of Sliding Mode Control

2018-11-21

Jian Pan , Wei Li , Haipeng Zhang

High permeability and low loss bioinspired soft magnetic composites with nacre-like structure for high frequency applications

2019-01-27

Wangchang Li , Haowen Cai , Yue Kang +6 more

Vibration analysis for electronic equipment

1990-03-01

W. Redman-White

Magnetic Bearings

2009-01-01

Gerhard Schweitzer , Eric H. Maslen

Theory and Use of the EM Algorithm

2010-01-01

Maya R. Gupta

Tribology and Mechanics of Magnetic Storage Devices

1990-01-01

Bharat Bhushan

Linear Electric Actuators and Generators

1997-03-28

Ion Boldea , Syed A. Nasar

Linear electric actuators (LEAs) and linear electric generators (LEGs) are widely used electromagnetic devices. This book deals with LEAs that convert electric energy into controlled mechanical motion of limited travel … Linear electric actuators (LEAs) and linear electric generators (LEGs) are widely used electromagnetic devices. This book deals with LEAs that convert electric energy into controlled mechanical motion of limited travel and LEGs that transform mechanical energy into electric energy. Examples range from loudspeakers and microphones to magnetically levitated material transfer in ultraclean rooms. Much of the literature on linear actuators and generators covers the principles of operation and performance calculations of these devices. Little has been published on their control or on detailed design methodologies. This book presents the first unified treatment of the subject, including the construction, operation, control and design of LEAs and LEGs. Chapters describe linear induction, permanent-magnet, linear reluctance, switched reluctance, and linear stepper actuators, as well as various types of linear electric generators. The text is amply illustrated with numerous design examples.

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Dynamics of Rotors and Foundations

1993-01-01

Erwin Krämer

On the dynamics of the vibration-driven multipole magnetoactive bristlebot

2025-06-25

Marius Reiche , Lena Zentner , Tatiana I. Becker | Archive of Applied Mechanics

Stability and optimal control of a fully-actuated tilt-rotor with delayed feedback

2025-06-24

Juan López‐Hernández , César‐Fernando Méndez‐Barrios , Adrián-Josué Guel-Cortez | Optimization and Engineering

Effect of geometrically nonlinear damping on systems controlled by negative derivative feedback under harmonic excitation

2025-06-24

A. T. EL-Sayed , Asma Alanazy , Y. A. Amer +1 more | Journal of low frequency noise, vibration and active control

This study investigates the effectiveness of a Negative Derivative Feedback (NDF) controller in suppressing vibrations in a two-degree-of-freedom nonlinear system subjected to harmonic excitation. The system incorporates geometrically nonlinear damping, … This study investigates the effectiveness of a Negative Derivative Feedback (NDF) controller in suppressing vibrations in a two-degree-of-freedom nonlinear system subjected to harmonic excitation. The system incorporates geometrically nonlinear damping, which introduces complex dynamic behavior. To analyze the system’s response, the averaging method is employed to derive approximate analytical solutions, while the fourth-order Runge–Kutta method is used for numerical integration. Particular attention is given to the case of simultaneous resonance <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>(</mml:mo> <mml:mrow> <mml:mi>Ω</mml:mi> <mml:mo>=</mml:mo> <mml:msub> <mml:mi>ω</mml:mi> <mml:mn>1</mml:mn> </mml:msub> <mml:mo>,</mml:mo> <mml:msub> <mml:mi>ω</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:mo>=</mml:mo> <mml:msub> <mml:mi>ω</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:mrow> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> , a critical condition in nonlinear dynamics. Comparative analysis between the numerical simulations and the perturbation-based solutions confirms the high accuracy and reliability of the proposed control strategy. Furthermore, the impact of key system parameters on vibration attenuation is examined. The results highlight the NDF controller’s potential in enhancing the performance of nonlinear vibration mitigation devices, with direct applications to systems such as Centrifugal Pendulum Vibration Absorbers.

Modeling and numerical analysis of a complex partially liquid-filled rotor under multi-frequency whirl: theoretical development and experimental validation

2025-06-24

Bowen Yang , Qihang Li , Xing Shao +4 more | Mechanical Systems and Signal Processing

Novel adaptive extended state observer method of active disturbance rejection control for sensorless IPMSMs based on high-frequency square wave injection

2025-06-24

Liwei Wang , Hong Miao | Journal of Power Electronics

Finite-time position tracking control for magnetic levitation systems with suspension air-gap constraints

2025-06-23

Qixun Lan , Pik Kong Yue , Na Liu +2 more | Applied Mathematical Modelling

Study on Dynamic Characteristics of an Aeroengine Dual-Rotor System with Inter-Shaft Rub-Impact Based on Finite Element Model

2025-06-23

Shuaiping Guo , Jing Wang , Guo Yi Zhou +3 more | Journal of Vibration Engineering & Technologies

A Study on the Performance of a New Type of Eddy Current Damper with Inserted Magnetic Iron Rods

2025-06-20

Lin Lü , Yihang Wang , Guoqing Di | Journal of Vibration Engineering & Technologies

A Mechanism-Data Hybrid-Driven Modeling Method for Vibration Response Prediction of the Magnetically Suspended Rotor System

2025-06-20

Mengting Zhu , Xiaoyue Liu , Cong Peng +3 more | Guidance Navigation and Control

High-precision stable control method for the rotor axis trajectory of flywheel energy storage in maglev trains

2025-06-20

Dongyuan Lv , Qichao Lv , Wen Ji +2 more | Journal of Vibration and Control

To address the suspension airgap fluctuations and vertical instability caused by rotor vibration in magnetically suspended flywheel energy storage systems (MS-FESS) under high-speed operating conditions of maglev trains, this paper … To address the suspension airgap fluctuations and vertical instability caused by rotor vibration in magnetically suspended flywheel energy storage systems (MS-FESS) under high-speed operating conditions of maglev trains, this paper proposes a high-precision stable control method for rotor axis trajectory. In complex operational scenarios (e.g., high-speed cruising, emergency braking), unbalanced disturbances and sensor harmonic noise in the magnetically suspended flywheel rotor dynamically couple through the mechanical base and suspension system, degrading airgap control accuracy. Existing methods exhibit limitations in coupling modeling, dynamic adaptability, and collaborative suppression of multi-source disturbances, failing to meet high-speed operational demands. To resolve these issues, this study first establishes a multi-degree-of-freedom coupled dynamic model of the flywheel-maglev system, quantifying the vibration energy transfer mechanism from the base to suspension electromagnets and revealing the nonlinear correlation between airgap fluctuations and compensation currents. Subsequently, an adaptive tracking filter with dynamic parameter adjustment is designed to synchronously suppress synchronous and harmonic disturbances through real-time speed tracking and phase correction, addressing the phase lag issue of traditional notch filters across wide speed ranges. Finally, experimental validation is conducted on a high-speed maglev flywheel prototype and a simulated train platform. Results demonstrate that the proposed method reduces base vibration intensity by 8–10 times, decreases suspension airgap fluctuation amplitude by 40%, stabilizes rotor axis trajectory amplitude within 10 μm, and limits vibration acceleration below 0.05 m/s 2 , significantly enhancing system stability and energy efficiency. This research dynamically adjusts the filter parameters through real-time rotational speed tracking and phase correction, overcoming the phase lag problem of traditional notch filters. It provides theoretical and practical guidance for vibration suppression and trajectory control in the flywheel energy storage system of maglev trains.

Investigation of Gravity Compensation Control Strategy for a Hybrid Active–Passive Following System

2025-06-20

Qingxia Wang , Yong Jiu Shi , Shunzhou Huang +2 more | Arabian Journal for Science and Engineering

Crack propagation in an energy storage flywheel rotor using finite element method

2025-06-20

Ailene Nuñez , Aristotle T. Ubando , Jeremias A. Gonzaga +3 more | Results in Engineering

Theoretical Contribution to multiphysical modeling of flywheel energy storage systems with a focus on thermal effects in magnetic bearings

2025-06-19

Bruno Rende , Ilmar F. Santos | Journal of Energy Storage

Review on Research and Development of Magnetic Bearings

2025-06-19

Yuanhao Du , Gan Zhang , Wei Hua | Energies

This paper reviews the research advancements and development in magnetic bearings. Firstly, from the technical principle, the design differences and application areas of active magnetic bearings, permanent magnetic bearings and … This paper reviews the research advancements and development in magnetic bearings. Firstly, from the technical principle, the design differences and application areas of active magnetic bearings, permanent magnetic bearings and hybrid structures are clarified. At the key technology level, focusing on electromagnetic design optimization, control strategy innovation and power-driven energy management, the breakthrough points of multi-physics coupling modeling, vibration suppression and energy efficiency improvement are revealed. Through the analysis of its engineering cases in the fields of high-speed motors, flywheel energy storage, aerospace and so on, the feasibility and economy of the technical scheme are verified. Further, the technical bottlenecks that need to be broken through are pointed out. For the future trend, this paper suggests that integration of interdisciplinary high-precision modeling, intelligent control algorithm and miniaturized integrated design should be deeply integrated to promote the large-scale application of magnetic bearing in frontier fields. This paper provides theoretical reference and engineering practice guidance for the technology iteration and cross-field integration of magnetic bearings.

Design and Optimization of a Large-Air-Gap Voice Coil Motor with Enhanced Thermal Management for Magnetic Levitation Vibration Isolation in a Vacuum

2025-06-19

Junren Mu , He Zhang | Actuators

This study presents the design, optimization, and experimental validation of a large-air-gap voice coil motor (LAG-VCM) for high-precision magnetic levitation vibration isolation in vacuum environments. Key challenges arising from a … This study presents the design, optimization, and experimental validation of a large-air-gap voice coil motor (LAG-VCM) for high-precision magnetic levitation vibration isolation in vacuum environments. Key challenges arising from a large air gap, including pronounced leakage flux and a reduced flux density, were addressed by employing the equivalent magnetic charge method and the image method for the modeling of permanent magnets. Finite element analysis was applied to refine the motor geometry and obtain high thrust, low ripple, and strong linearity. To mitigate the severe thermal conditions of a vacuum, a heat pipe-based cooling strategy was introduced to efficiently dissipate heat from the coil windings. The experimental results demonstrate that the optimized LAG-VCM delivers a thrust of 277 N with low ripple while effectively maintaining coil temperatures below critical limits for prolonged operation. These findings confirm the suitability of the proposed LAG-VCM for vacuum applications with stringent requirements for both a large travel range and stable, high-force output.

I-f Control Method of IPMSM to Reduce Oscillation Speed with High Torque

2025-06-19

Shi Jin , Jong-Won Choi | The Transactions of the Korean Institute of Power Electronics

The bio-inspired spider web dynamic vibration absorber applied to the transverse-torsional-axial vibration in rotor systems

2025-06-18

Feifan He , Jingtao Du , Yang Liu | Mechanical Systems and Signal Processing

Analytical Optimization of a Rotary Electromagnetic Shunt Damper for Freely Rotating Two-DoF Torsional Vibration System

2025-06-18

Tetsushi Shiono , Kentaro Takagi , Toru Ikegame +4 more | Journal of vibration and acoustics

Abstract This study explores for the first time the analytical optimization of a rotary electromagnetic shunt damper. Most previous studies on electromagnetic shunt dampers focus on linear DC motors or … Abstract This study explores for the first time the analytical optimization of a rotary electromagnetic shunt damper. Most previous studies on electromagnetic shunt dampers focus on linear DC motors or voice coil motors, with limited exploration of freely rotating torsional vibration systems. Moreover, traditional outcomes from the established fixed point method for mechanical dynamic vibration absorbers are not directly applicable. This is because the configuration of a spring and a dashpot in the electrical-mechanical analogy of the electromagnetic shunt damper differs from that of an ordinary mechanical dynamic vibration absorber. This paper presents an optimization of the resistance and capacitance (or PI gain of current control) of the electromagnetic shunt damper for a freely rotating two-DoF vibration system with an electromagnetic motor. This paper analytically derives a solution that minimizes the peak of the frequency response using the fixed-point method. As a result, we found that there are cases where there are three fixed points of the transfer function or where the gains of two fixed points cannot be aligned. The analytical optimal solution obtained is not one, but is divided into two or three cases, depending on the magnitude of the electromechanical coupling. Through numerical examples, this paper discusses how the optimal solutions depend on the magnitude of the electromechanical coupling. In the experiment, an electromagnetic shunt damper was realized using a commercially available inverter and electromagnetic motors attached to a two-DoF torsional vibration system, and a damping effect of more than 27 dB was obtained.

A study on logarithmic convergence law smooth mode control of magnetic levitation train levitation system

2025-06-16

Lingwei Fei , Chunjun Chen | International Conference on Frontiers of Traffic and Transportation Engineering (FTTE 2022)

Experimental identification of residual unbalances in run-up high-speed rotor system integrated with active magnetic bearing by synchronized virtual trial unbalances

2025-06-16

Gyan Ranjan , Rajiv Tiwari , Harshal B. Nemade | Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science

An identification procedure is described to obtain the residual unbalances in high-speed rotor systems integrated with Active Magnetic Bearing (AMB) using Synchronized Virtual Trial Unbalances (SVTU) as magnetic forces. The … An identification procedure is described to obtain the residual unbalances in high-speed rotor systems integrated with Active Magnetic Bearing (AMB) using Synchronized Virtual Trial Unbalances (SVTU) as magnetic forces. The practical difficulty in identification of residual unbalances utilizing manual trial unbalances, and a large number of rotor runs is reduced with the implementation of Modified Influence Coefficient Method (MICM). The half-spectrum displacement responses of the accelerated system are utilized along with the magnitude and phase of SVTU to estimate the influence coefficients related to operating frequencies of the system. Moreover, the crossing of critical speed with minimal power consumption in the rotor-bearing system is achieved using Switching Mode Control (SMC) of the bias current and PID controller. The bias current is switched between low and high values to incorporate the adequate requirement of the control current from the controller, thereby reducing the overall power consumption of the AMB system. Also, the practical complications encountered in generating the SVTU in the experimental test rig during the run-up are addressed in the present work. The excitation frequencies of SVTU is essential to be matched with the operating frequencies of rotor-AMB system in real-time to imitate the characteristics of the manual added unbalances. To verify the effectiveness of proposed method, the estimation procedure is carried out for both the conventional influence coefficient method using manual trial unbalances and the MICM using SVTU. The magnitude and phases of residual unbalances identified using MICM are consistent with that obtained using the conventional influence coefficient method with AMB control. The balancing of the rotor-AMB system is performed using the estimated unbalances with a 53%–62% reduction in the time-domain vibrational amplitudes and currents generated by controller at high speeds. The present work aims to solve the problems associated with fault identification in the rotor system supported on conventional bearing by the effective application of magnetic excitation through AMB and influence coefficients.

Flutter Analysis of a 2.5D C/SiC Composite Blade Considering Wake Excitation

2025-06-14

Qian Xu , Lei Hou , Shuangxing Ren +3 more | Journal of Vibration Engineering & Technologies

The Influence of Axial-Bearing Position of Active Magnetic Suspension Flywheel Energy Storage System on Vibration Characteristics of Flywheel Rotor

2025-06-13

Lei Wang , Tielei Li , Zhengyi Ren | Actuators

This study introduces a flywheel rotor support structure for an active magnetic suspension flywheel energy storage system. In this structure, there is an axial offset between the axial-bearing position and … This study introduces a flywheel rotor support structure for an active magnetic suspension flywheel energy storage system. In this structure, there is an axial offset between the axial-bearing position and the mass-center of the flywheel rotor, which affects the tilting rotation of the flywheel rotor and which causes the coupling between its tilting rotation and radial motion. Therefore, the influence of the bearing position on the vibration characteristics of the flywheel rotor is explored in this paper. The tilting rotation constraint of the flywheel rotor by axial active magnetic bearing (AAMB) is analyzed, and the radial active magnetic bearing (RAMB) is equivalently treated with dynamic stiffness and dynamic damping. Based on this, a dynamic model of the active magnetic suspension rigid flywheel rotor, considering the position parameter of the axial bearing, is established. To quantify the axial offset between the position of the AAMB and the mass-center of the flywheel rotor, the axial-bearing position offset ratio γ is defined. The variation trend of the vibration characteristics of flywheel rotor with γ is discussed, and its correctness is validated through experiments. It is indicated that, with the increase of γ, the second-order positive precession frequency of the flywheel rotor decreases obviously, and the influence of the gyroscope torque gradually weakens. Meanwhile, its second-order critical speed ω2c decreases significantly (when γ is 0.5, ω2c decreases by about 62%); ω2c corresponds to the inclined mode, revealing that the offset ratio γ has a prominent influence on the critical speed under this mode. In addition, as γ increases, the mass unbalance response amplitude of the flywheel rotor under the speed of ω2c decreases significantly. The reasonable design of the axial-bearing position parameter can effectively improve the operational stability of the active magnetic suspension flywheel energy storage system.

Real-Time Adaptive Artificial Neural Network Control of a Magnetic Levitation System

2025-06-13

Sunghwan Shin , Hyeong-Joon Ahn | Transactions of the Korean Society of Mechanical Engineers A

Research on stability control of flexible rotor system under complex fluid excitation

2025-06-13

Weimin Wang , Xiaolin Zheng , Kan Chen +3 more | Mechanical Systems and Signal Processing

Research on the Dynamic Characteristics of a Typical Medium–Low-Speed Maglev Train–Bridge System Influenced by the Transverse Stiffness of Pier Tops

2025-06-12

Yang Cui , Guo Xiang-rong , Hongwei Mao +1 more | Applied Sciences

With the continuous development of maglev transportation technology, medium–low-speed maglev trains have been widely implemented in many countries. However, due to the limitations of existing specifications, the stiffness limit values … With the continuous development of maglev transportation technology, medium–low-speed maglev trains have been widely implemented in many countries. However, due to the limitations of existing specifications, the stiffness limit values of the large-span main girders used in medium–low-speed maglev trains have not been unified. To address this issue, this study takes a specific bridge on a dedicated maglev line as an example and uses self-developed software to model the vehicle–bridge dynamic system. The natural vibration characteristics and vehicle–bridge coupling vibration response of the bridge are calculated and analyzed. Based on this, the influence of pier top stiffness on the dynamic characteristics of a typical medium–low-speed maglev train–bridge system under different working conditions is investigated, with a focus on the lateral line stiffness at the pier top. The results show that vehicle speed has no significant effect on the lateral displacement of the main girder, the lateral displacement of the pier top, the lateral acceleration of the pier top, and the transverse and longitudinal angles of the beam end, and no obvious regularity is observed. However, in the double-track operating condition, the vertical deflection of the main girder is significantly higher than that in the single-track operating condition. As the lateral linear stiffness at the pier top increases, the fundamental frequency of the bridge’s lateral bending vibration gradually increases, while the fundamental frequency of longitudinal floating gradually decreases. The lateral displacements, including those of the main girder, pier top, and beam ends, all decrease, whereas the lateral and vertical vibration accelerations of the main girder and the train are less affected by the lateral stiffness at the pier top.

Determination of the inductiveness of a physical model of track coils for high-speed transport

2025-06-07

Oleksandr Holota , D. V. Ustymenko , А. М. Mukha +2 more | Technology audit and production reserves

The object of research is the parameters and characteristics of track coils with different design parameters for a physical model of high-speed maglev transport. The problem that arises in such … The object of research is the parameters and characteristics of track coils with different design parameters for a physical model of high-speed maglev transport. The problem that arises in such a system is the untimely switching on of the track coils, which leads to a malfunction due to a short-term disappearance of the traction force. Solving this problem will allow the vehicle to improve the conditions of movement of the high-speed maglev transport. This will make it possible to make a reasonable choice of the parameters of the track coil of a physical model of high-speed transport, which would have the required inductance value at different switching modes. The required switching frequency will depend on the desired speed of movement of the vehicle and the parameters of the track coils. An important task within the framework of research on maglev transport is the development and creation of a fundamentally new control system. Such a system would have a track structure with traction coils of a rational shape and parameters that would implement certain control processes of the experimental unit. The task of the research is to create a physical model of track coils of high-speed transport and to conduct an experimental determination of the dependence of electrical parameters (inductance) on the frequency of a sinusoidal signal for different winding parameters of track coils. To implement the technical solution, a physical model of the track coil was created, which takes into account the necessary requirements for the study. The search for more favorable technological solutions requires conducting research on electrical processes in the track structure circuit of the physical model of the track coil. This will allow to substantiate the prerequisites for the creation, accumulation and transfer of the necessary energy to the track coils in physical models that will simulate the principles of movement and control of magnetic levitation transport. During the research, the results were obtained by applying mathematical statistics methods and the development of a track coil with optimal parameters for a physical model of a high-speed transport experimental unit was carried out. The results obtained with the correct selection of the track coil parameters can create prerequisites for the further development of an experimental switching system for physical model of high-speed transport. In this case, the operating reserve can be determined by the required reserve of effective operation of the track coils to implement the necessary laws of rolling stock control.

ANALYSIS OF DYNAMIC BEHAVIOUR OF MAGNETIC-LIQUID DOUBLE SUSPENSION BEARING CRACKED ROTOR SYSTEM

2025-06-05

Theoretical analysis of different feedback concepts for active vibration control of rotating machines with current‐controlled electrodynamic actuators between machine feet and steel frame foundation

2025-06-01

Ulrich Werner | ZAMM ‐ Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik

Abstract The paper presents a theoretical analysis of different feedback concepts for active vibration control of rotating machines with current‐controlled electrodynamic actuators between the machine feet and the steel frame … Abstract The paper presents a theoretical analysis of different feedback concepts for active vibration control of rotating machines with current‐controlled electrodynamic actuators between the machine feet and the steel frame foundation. A generalized mathematical formulation—based on a detailed formulation and on simplified formulations—has been derived, which can be used for different vibration models with different degrees of discretization. In the simplified mathematical formulations, the control parameters are implemented directly in the stiffness and damping matrix of the vibration system or, under special conditions, even directly in the stiffness and damping coefficients of the actuators. For these limit conditions, the controlled system can be replaced by a substituted mechanical system, which allows rapid predictions and optimizations regarding active vibration control of rotating machines without too much effort. Based on the generalized mathematical formulations, a very simplified model of an induction motor is analyzed with typical excitations such as mechanical unbalance, electromagnetic forces in the air gap, and vibrations of the base. The paper shows how the vibration system is affected by different feedback concepts and demonstrates the effectiveness of these concepts.

Near-zero-vibration non-contact transportation by single-body decoupled 2-DOF magnetic levitator for multi-size targets with unknown mass

2025-06-01

Jae Woo Jung , Eun Kyu Kim , Hyeong Min Yoon +1 more | Precision Engineering

Elimination of the vibration center shift in the nonlinear oscillations of a MAGLEV vehicle subjected to steady and unsteady aerodynamic forces: Second‐order multiple scales analysis

2025-06-01

Mohamed M. M. Ibrahim , Ali Kandil , Waheed K. Zahra +1 more | ZAMM ‐ Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik

Abstract This study explores the dynamical behavior and stability of a magnetic levitation (MAGLEV) vehicle system controlled by a proportional‐derivative (PD) controller under steady and unsteady aerodynamic forces. The governing … Abstract This study explores the dynamical behavior and stability of a magnetic levitation (MAGLEV) vehicle system controlled by a proportional‐derivative (PD) controller under steady and unsteady aerodynamic forces. The governing equation for the model is derived, showing that the displacement control gain affects the vehicle's linear stiffness, identifying conditions for positive, quasi‐zero, and negative stiffnesses. From previous studies, the model showed a shift in its vibration center, which might risk the safe operation of the vehicle as the suspension gap became smaller. In addition, this shift can generate deviations between the approximate‐analytical and numerical results. The main idea of this paper is to suggest an effective treatment for this shift, in the positive stiffness case, by implementing a convenient slight reduction in the value of the nominal current during its dynamical state under aerodynamic lift force. This could enhance the safety level during the vehicle's operation. Moreover, in the positive stiffness case, the multiple scales (MS) method is used to provide an approximate second‐order analytical solution to the model. The analysis includes the vehicle's motion stability utilizing the first method of Lyapunov. The effects of changing the vehicle mass, unsteady aerodynamic force amplitude, vehicle speed, the displacement, and speed control gains on vibration level and stability are examined. For the quasi‐zero stiffness case, the vibration characteristics of the MAGLEV vehicle are numerically simulated and investigated using the fourth‐order Runge–Kutta (RK4) method. The speed control gain should be properly chosen as it may delay reaching steady‐state conditions despite its effectiveness in mitigating large vibrations caused by low‐frequency external lift forces. Eventually, the negative stiffness case operation should not be allowed as the system exhibits dangerously high vibration amplitudes.

Reliability study of absolute position sensors for highspeed maglev trains

2025-06-01

Hang Sun , Yan Quan Sun , Zhou Tian | Journal of Physics Conference Series

Abstract To achieve closed-loop control of the traction and operation control systems in high-speed maglev trains, a positioning and speed measurement system is indispensable, and its reliability is equally critical. … Abstract To achieve closed-loop control of the traction and operation control systems in high-speed maglev trains, a positioning and speed measurement system is indispensable, and its reliability is equally critical. This paper designs a novel absolute position sensor with a new structural configuration. The Code Reader section primarily consists of two photoelectric switches and four coils on the same plane, making the structure simpler compared to the traditional U-slot design. The study focuses on the reliability of the designed sensor, analyzing both the reliability of the absolute position sensor itself and its impact on the overall positioning and speed measurement system. Furthermore, through simulations of fault diagnosis techniques for the sensor’s hardware circuit, the study verifies that the applied fault diagnosis method can accurately locate most fault positions, effectively improving the reliability of the designed absolute position sensor.

Design and initial experimental verification of a high-speed electrodynamic levitation measurement system utilizing modular magnetic field sources and aluminium rails

2025-06-01

K. Öztürk , Hakkı Mollahasanoğlu , Murat Abdioğlu +2 more | Measurement

Dynamic Effects of Micro-Vibration Isolation of Control-moment Gyros on Spacecraft

2025-06-01

Qing Luo , Dongxu Li , Zhanji Wei +1 more | Advances in Space Research