Electromagnetic Suspension Research Articles

Design and Analysis of Electromagnetic Linear Actuation-Energy-Reclaiming Device Applied to a New-Type Energy-Reclaiming Suspension

In order to meet the increasing demand for high-performance and high-efficiency vehicles, this paper proposes a novel electromagnetic linear energy-reclaiming suspension technology based on the McPherson independent suspension, and analyzes its core component—ELA-ERD (Electromagnetic Linear Actuation Energy-Reclaiming Device). ELA-ERD, taking a shock absorber piston rod as the inner yoke, has a compact structure and reasonable layout by integrating the structural features of the suspension. In this paper, the design process of ELA-ERD is elaborated in detail. Aiming at the problem of over-saturation of the inner yoke magnetic density, this paper proposes a method to optimize the magnetic circuit by increasing the size of the inner yoke within the effective working area of the moving coil, thus effectively improving the electromagnetic characteristics of ELA-ERD. Moreover, the effect and potential of energy reclaiming on ELA-ERD were studied by using finite element software. The study on the energy-reclaiming law of ELA-ERD was carried out from the perspective of the changes in vibration frequency and amplitude. In addition, the internal relationship between the energy-reclaiming voltage and the vibration velocity was revealed in this work, and the energy-reclaiming voltage coefficient Ke was defined. Through calculation of a large amount of model data, the Ke value applicable to the designed ELA-ERD in this paper was approximately set to 4.5. This study lays an important theoretical foundation for the follow-up studies.

Control Methods for Levitation System of EMS-Type Maglev Vehicles: An Overview

As new advanced vehicles, electromagnetic suspension (EMS)-type maglev trains have received wide attention because of their advantages such as high speed, no mechanical friction, low noise, low cost and energy consumption, strong climbing ability, and green environmental protection. The open-loop instability is one of the key points and difficulties for the levitation control systems of maglev trains. The closed-loop feedback control method must be applied to realize stable levitation. However, there are currently many levitation control methods just in theory. Considering their advantages and disadvantages, it is a major demand for maglev trains to select efficient, stable, applicable, and cost-saving methods to improve their dynamic performance and safety, which motivated this review. First, the current status of research on maglev trains is introduced in this paper, including types, system components, and research modes in various countries, followed by an analysis of the levitation control methods for EMS-type maglev trains. Then, the technical characteristics of the levitation control systems are described according to the basic principles of levitation systems, model building, mathematical derivation, and control objectives. Next, three kinds of typical levitation control methods are reviewed, namely, linear state feedback methods, nonlinear control methods, and intelligent control methods, according to their improvements and applications. Lastly, we summarize and evaluate the advantages and disadvantages of the three methods, and future developments of levitation control are suggested.

Robust Control of an Electromagnetic Suspension System

The electromagnetic suspension system is a motivating and inspiring project for students to investigate the primary principles of electrical engineering, such as control theory, including robust performance and modeling uncertainty. This paper studies robust control methods for an electromagnetic suspension system with H_2, H_infinity and mu-synthesis control approaches to provide robust system performance in the presence of uncertainties and disturbances. System uncertainties are critical parts of the interconnected system modeling, affecting its performance. The control methods tackle the system uncertainties, including unmodeled dynamics, parametric uncertainty, and linearization error. Robust performance analysis for all proposed control methods is provided, and closed-loop system performance is illustrated. The performance robustness is validated using illustrative simulation results.

Fuzzy Linear Active Disturbance Rejection Control Method for Permanent Magnet Electromagnetic Hybrid Suspension Platform

The permanent magnetic suspension (PMS) train has distinct advantages in reducing energy consumption and increasing the suspension air gap. Aiming at the problems of uncontrollable magnetic field and underdamping of the PMS system, the electromagnetic damping structure is introduced, and a fuzzy linear active disturbance rejection control (Fuzzy-LADRC) method with an air gap deviation integrator is proposed. Firstly, the permanent magnet electromagnetic hybrid suspension (PEMS) system is constructed, and the model analysis is carried out to prove that the system is controllable and observable, and the hardware experimental platform is built. Secondly, a LADRC method is designed based on the model of the platform suspension control unit, and fuzzy control is introduced into the LADRC state error feedback control theory for parameter self-tuning to improve the adaptability and robustness of the platform. At the same time, an air gap deviation integrator is introduced to further improve the control accuracy. Finally, the comparison experiments with LADRC and PID control methods are carried out in terms of stability, anti-interference, robustness and adaptability. The experimental results show that the proposed Fuzzy-LADRC method has the best control effect. It provides practical reference for improving the stability of the PMS train.

Design and Hybrid Control of a New Self-Powered Electromagnetic Suspension Actuator Matched with Non-Pneumatic Tire

Design and Hybrid Control of a New Self-Powered Electromagnetic Suspension Actuator Matched with Non-Pneumatic Tire

Tuning of PID controller using genetic algorithm for an electromagnetic semi-active suspension system

Electromagnetic suspension of vehicles has advantage of improved ride comfort and drivability. Electromagnetic levitation has been in use in Maglev trains for smoother transportation. However, application of electromagnetic suspension system was limited by its cost and weight. This paper focuses study on use of an electromagnet and permanent magnet hybrid magnet setup and compares the control method to stabilize the suspension system by genetic algorithm optimization, auto tuning technique and fuzzy logic controller for tuning the Proportional-Integral-Derivative (PID) controller for making the system stable. MATLAB-Simulinkanalysis of hybrid magnetic suspension system show stabilization by reduction of the errors in the closed loop control system. Realization in a real time setup may be possible by varying the magnetic field developed in the electromagnet to control the force of repulsion between the electromagnet and permanent magnet.

Non-contact Gripping of Thin Steel Plates by Electro Magnetic Suspension

Non-contact Gripping of Thin Steel Plates by Electro Magnetic Suspension

A Review of Electromagnetic Energy Regenerative Suspension System & Key Technologies

The active suspension has undoubtedly improved the performance of the vehicle, however, the trend of “lowcarbonization, intelligence, and informationization” in the automotive industry has put forward higher and more urgent requirements for the suspension system. The automotive industry and researchers favor active energy regeneration suspension technology with safety, comfort, and high energy regenerative efficiency. In this paper, we review the research progress of the structure form, optimization method, and control strategy of electromagnetic energy regenerative suspension. Specifically, comparing the pros and cons of the existing technology in solving the contradiction between dynamic performance and energy regeneration. In addition, the development trend of electromagnetic energy regenerative suspension in the field of structure form, optimization method, and control technology prospects.

MATHEMATICAL MODEL OF ELECTRO-MECHANICAL VIBRATION TRANSDUCERS BASED ON THE LEVITATION EFFECT

At present, one of the urgent problems in the energy and industry is to improve the reliability of the operation of various equipment. An effective method for increasing the reliability of equipment is diagnosing the state of machines and predicting their performance. Vibration control methods are widely used to diagnose rotary rotating machines. By the nature of the vibration process of the machine, it is possible to determine the degree of wear and, accordingly, the technical condition of the machines. In measuring technology for diagnostics of low-speed equipment with rotation frequencies of a unit of Hz, for example, hydroelectric generators of hydroelectric power plants, inertial electromechanical converters are used. The latest developments of such converters use an electromagnetic suspension with parametric feedback, which allows you to control the rigidity of the oscillatory system. However, for centering the moving part in electromechanical converters, flexible guides are used, which are sources of dry friction, which complicates the simulation of measurement processes and limits the sensitivity threshold to a minimum. In addition, flexible guides limit the frequency range of the converters. Currently, the most promising direction for solving this problem is the levitation effect, which allows you to completely exclude mechanical contact and, accordingly, reduce the sensitivity threshold of the transducer. From the analysis of literary sources, it follows that there are relatively few publications in this area. This article provides an analysis of existing vibration transducers and proposes a mathematical model of the magnetic levitation system, taking into account the influence of the electromagnetic force nonlinearity, as well as a method for selecting the feedback control unit parameters to stabilize the mass position of the vibration sensor.

AN AUTOMATED SYSTEM FOR DESIGNING THE ELECTROMAGNETIC SUSPENSION OF THE TRAIN “MAGLEV”

The design features of the electromagnetic suspension of the Maglev train are discussed. A software tool has been developed, allowing to automate the process of designing the electro-magnetic suspension by setting the values of the input parameters and determining the values of the characteristic quantities of the suspension. In the developed automated system, the direct and reverse tasks of designing an electromagnetic suspension are solved, the parameters of the control winding are determined, the values of the characteristic quantities are optimized. Block diagrams schemes and system classes are presented.

Analysis of the Speed Limit of Transrapid Maglev Train Explored From the Perspective of Its Suspension and Guidance Systems

In recent years, research on high-speed or ultra-high-speed maglev systems has become increasingly popular, and different countries or teams have been committing to several different suspension technologies. Among them, due to the profound accumulation of research on the normal-conducting electromagnetic suspension technology, China is actively adopting this suspension technology to develop a new high-speed maglev train faster than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$600~km/h$ </tex-math></inline-formula> , and this work is mainly on the basis of Transrapid (TR) trains and Shanghai Maglev Line (SHML). To evaluate the feasibility of this project, the speed limit of the TR maglev system was explored from the perspective of its suspension and guidance systems. The analysis process was carried out from two aspects of aerodynamic interference and track irregularity. As for aerodynamic interference, the aerodynamic and electromagnetic simulation models were established based on the actual maglev train. The anti-interference abilities of the suspension and guidance systems were analyzed from two aspects of steady-state and transient-state respectively. The results verified that the train could operate safely when its speed below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$800~km/h$ </tex-math></inline-formula> and the cross-wind speed below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$26~m/s$ </tex-math></inline-formula> . As for track irregularity, based on the actual track construction indicators of the SHML, the relationship between suspension gap fluctuation and the train speed was studied through a dynamic calculation model of the suspension control system. The results showed that the suspension system had a risk of track collision when the train speed was greater than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$717~km/h$ </tex-math></inline-formula> . In summary, from the perspective of its suspension and guidance systems, the current TR maglev system on the SHML has an upper speed limit. The conclusion would be valuable for the development of ultra-high-speed maglev systems in the future.

Numerical Simulation of The Magnetic Levitation System in State-Space Form

The maglev system is a technology that uses the repulsive force between magnets to float or levitate an object or vehicle. Maglev trains use electromagnets to counter the gravitational force of an object, so that the object can float in the air. With this technology, the resulting loss between the workpiece and the base can be eliminated. The technology used in this train is Electromagnetic Suspension (EMS). The research began by modeling the maglev system in the form of state space. Furthermore, the stability system model that has been built is analyzed. Finally, it is analyzed how the numerical simulation of an open loop without control is analyzed. The result of this research is that the floating system (maglev) is an unstable system if it is run in an open loop, so the maglev system requires sensors and controls in its operation.

Random vibration analysis of the maglev vehicle-guideway system using a probability density evolution method with uncertain parameters

Random dynamic analyses of maglev vehicle-guideway coupled systems are of significant interest but have yet been comprehensively performed. This paper presents a time-dependent coupled random model of a maglev vehicle-controller-guideway-pier to investigate random vibration characteristics of the dynamic system. In the study, a 12-degree-of-freedom vehicle model is considered, a three-dimensional detailed guideway model is established using the finite element method, and the electromagnetic levitation force is controlled with a current feedback controller. Then, the generalized F-discrepancy representative point set selection strategy and probability density evolution method, which can consider multiple random parameters, are combined to analyze the dynamic system. Random vehicle parameters and irregularity are introduced and the mean value, standard deviation, limits satisfying different probability guarantee rates, and probabilistic information are calculated. The model was validated with field measurement data from an electromagnetic suspension (EMS) maglev line. In addition, the Monte Carlo method was used to assess the accuracy and efficiency of the proposed method. The results demonstrate that the proposed method has good accuracy and efficiency. The effects of vehicle running speed, random irregularity, and random vehicle loads on the dynamic vibration of the system are discussed.

Numerical Simulation of The Magnetic Levitation System in State-Space Form

The maglev system is a technology that uses the repulsive force between magnets to float or levitate an object or vehicle. Maglev trains use electromagnets to counter the gravitational force of an object, so that the object can float in the air. With this technology, the resulting loss between the workpiece and the base can be eliminated. The technology used in this train is Electromagnetic Suspension (EMS). The research began by modeling the maglev system in the form of state space. Furthermore, the stability system model that has been built is analyzed. Finally, it is analyzed how the numerical simulation of an open loop without control is analyzed. The result of this research is that the floating system (maglev) is an unstable system if it is run in an open loop, so the maglev system requires sensors and controls in its operation.

Vehicle Stability Analysis under Extreme Operating Conditions Based on LQR Control.

Under extreme working conditions such as high-speed driving on roads with a large road surface unevenness coefficient, turning on a road with a low road surface adhesion coefficient, and emergency acceleration and braking, a vehicle's stability deteriorates sharply and reduces ride comfort. There is extensive existing research on vehicle active suspension control, trajectory tracking, and control methods. However, most of these studies focus on conventional operating conditions, while vehicle stability analysis under extreme operating conditions is much less studied. In order to improve the stability of the whole vehicle under extreme operating conditions, this paper investigates the stability of a vehicle under extreme operating conditions based on linear quadratic regulator (LQR) control. First, a seven degrees of freedom (7-DOF) dynamics model of the whole vehicle is established based on the use of electromagnetic active suspension, and then an LQR controller of the electromagnetic active suspension is designed. A joint simulation platform incorporating MATLAB and CarSim was built, and the CarSim model is verified by real vehicle tests. Finally, the stability of the vehicle under four different ultimate operating conditions was analyzed. The simulation results show that the root mean square (RMS) values of body droop acceleration and pitch angle acceleration are improved by 57.48% and 28.81%, respectively, under high-speed driving conditions on Class C roads. Under the double-shift condition with a low adhesion coefficient, the RMS values of body droop acceleration, pitch acceleration, and roll angle acceleration are improved by 58.25%, 55.41%, and 31.39%, respectively. These results indicate that electromagnetic active suspension can significantly improve vehicle stability and reduce driving risk under extreme working conditions when combined with an LQR controller.

Active Disturbance Rejection Control of Voice Coil Motor Active Suspension Based on Displacement Feedback

Electromagnetic active suspension is an important technique used in vehicles to improve ride comfort and handling stability. To achieve satisfactory suspension performance, the active suspension control requires strong robustness against the vehicle uncertainties and external disturbances. The voice coil motor (VCM) is applied to the active suspension. A suspension model considering the actuator is established. An active suspension controller based on the active disturbance rejection control (ADRC) method is proposed. Through the test platform built, it is demonstrated that the ADRC of VCM active suspension has better performance than the PID. The results indicate that the overshoot and adjustment time of ADRC controller is reduced by 80% and 50%, respectively. The body vertical displacement of the ADRC is 50% smaller than PID.

Electrical network optimization for electrically interconnected suspension system

The electrically interconnected suspension (EIS) can control vehicles' multiple-degree of freedom dynamics by designing a proper electrical network that connects independent electromagnetic suspensions. However, developing an electrical network (EN) for passive EIS to deal with complicated vibration is challenging. This paper proposes an EN optimization methodology for the EIS and experimentally validates the effectiveness of the optimized ENs with a hardware-in-the-loop (HIL) platform. First, a half-car model with a passive EIS is built and analysed for the EN design. The candidate EN structures are identified with an innovative method, which can cover all possible layouts with pre-determined complexity. Then, the optimization procedure of the EIS EN structures is determined to achieve a satisfactory level of ride comfort and handling stability. Finally, the optimized parameters of ENs are obtained with the genetic algorithm. In the HIL tests, the optimised ENs are validated with typical road vibration inputs and steering inputs. Experimental results demonstrate that a vehicle with optimized ENs can achieve better ride comfort and handling stability than vehicles with traditional passive suspension and unoptimized EIS electrical networks.

Nonlinear Robust Composite Levitation Control for High-Speed EMS Trains With Input Saturation and Track Irregularities

Unavoidable track irregularities continuously excite a traveling high-speed electromagnetic suspension (EMS) train. This issue deteriorates the levitation performances such as stability and comfortability. A robust levitation controller is critical for the EMS unit to suppress irregularities. In this work, a novel composite control scheme is proposed for high-speed maglev trains. It combines a fixed-time disturbance observer (FTDO) and a global finite-time controller (FTC). The FTDO is designed to estimate irregularities precisely within desired bandwidth, while the FTC is to address the fast dynamics of the levitation system of a high-speed maglev train. In addition, the command filter is integrated to increase the practicability of the composite control scheme. Theoretical analysis establishes the stability of the whole system. With ideal irregularity models and the field data measured from a commercial line, numerical simulations under various operation scenarios, including high speed, time-varying speed, gust and slope, verify that the proposed control scheme improves the air gap response while maintaining the stationarity of primary levitation and the ride comfortability for passengers. The simulations on a full bogie with load also demonstrate effectiveness of the proposed scheme.

Research on Electromagnetic Suspension Characteristics of 12-slot 6-Pole Single-winding BL-BLDCM

Background: The independent suspension winding in the dual-winding bearingless motor reduces the power density of the motor, and the amplitude of radial magnetic suspension force is affected by the limited slot space. As for the single-winding bearingless brushless direct current motor (BL-BLDCM), although preliminary researches have been carried out, a detailed analysis of its electromagnetic suspension characteristics is lacking. Objective: The magnetic suspension force mathematical model and electromagnetic suspension characteristics are analyzed through a single winding BL-BLDCM with a 12-slot/tooth stator and a 6-pole permanent magnet (PM) rotor. Method: First, the structure and working principle of the motor are introduced, and the mathematical model of the magnetic suspension is derived. Then, through Maxwell software, a twodimensional finite element model of the single-winding BL-BLDCM is established. Finally, the variation of the controllable magnetic suspension force and the coupling radial force along the vertical axis with the key structural parameters such as the air gap length, the PM pole arc coefficient, and the PM thickness are studied. Results: The law of radial controllable magnetic suspension force and the coupling radial force along the vertical axis changing with related parameters is given, and the analytical model of radial magnetic suspension force is verified. Conclusion: The proposed radial suspension force mathematical model is effective; the analysis results of electromagnetic suspension characteristics can provide a reference for the optimal design of single winding BL-BLDCM.

Study of an Energy-Harvesting Damper Based on Magnetic Interaction.

The saving and re-use of energy has acquired great relevance in recent years, being of great importance in the automotive sector. In the literature, it is possible to find different proposals for energy-harvesting damper systems (EHSA)—the electromagnetic damper being a highly recurrent but still poorly defined proposal. This article specifically focuses on studying the concept and feasibility of an electromagnetic suspension system that is capable of recovering energy, using a damper formed by permanent magnets and a system of coils that collect the electromotive force generated by the variation of the magnetic field. To study the feasibility of the system, it is necessary to know the maximum energy that can be recovered through the winding system; however, the difficulties in obtaining the derivative of the magnetic flux and its derivative for each position make the analytical method very tedious. This paper presents an experimental method with which to maximize energy recovery by defining the optimum relative position between magnet and coil.