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In a stability analysis of a levitation-melting system fed by a series resonant converter, it was found that a response delay of the current envelope signal in the coil to changes in the position of a levitating specimen has an impact on the system stability. Simulation results validate the developed analytical model. Experimental results from a 1-kW converter are presented to validate the analysis and the simulation results.

Magnetic levitation system has developed into a significant consideration in designing systems which require low losses due to friction and low energy consumption. In this paper the levitation inflexibility for suspending a steel ball and its distinctive application to wipe out friction and build machining accuracy is talked about. The procedures of feedback linearization and sliding mode control are proposed in this paper to accomplish relentless levitation. The procedure of feedback linearization is utilized as a part of this paper to change a nonlinear electromagnetic levitation framework into a linear framework. The proposed controller of sliding mode control is received for enhancing the power and robustness of the electromagnetic levitation system in the vicinity of commotions. Simulation results of sliding mode control demonstrate that the system has more prevailing and powerful bent of stifling disturbance and high inflexibility as equated with that utilizing traditional PID control strategy.

In this paper, the coupling of finite element and boundary element, known as FEM-BEM coupling, is used to numerically treat electromagnetic levitation problem based on eddy current. Main aim is to determine the dynamic characteristic of the levitating body in presence of magnetic field. A novel 3D formulation has been adapted that combines Lagrangian description and BEM-FEM coupling method for this purpose. Transient behaviour of the levitating body is described by Maxwell's equations and other constitutive equations. The coupling method is formulated using the boundary conditions on the common boundaries between FEM and BEM subdomains. Subsequent coding has been developed to simulate the problem in Matlab environment. An example similar to TEAM (Testing Electromagnetic Analysis Methods) workshop problem 28 has been used to examine the dynamic behaviour and efficiency of code.

Electromagnetic levitation system (EMLS) is inherently unstable and strongly non-linear in nature. In majority cases the closed loop system has been stabilized by classical controller utilizing linearlized model of EMLS. The linear classical controller has a restricted zone of operation. But it is essential to design a control scheme so that EMLS can operate for a large air-gap stably and at the same time the performance of controller will be satisfactory irrespective of any change in operating air-gap. This paper reports design, implementation and testing of piecewise linear control schemes to extend the range of operating air-gap for a voltage controlled (EMLS) in real time environment through dSPACE.

This paper proposes a unified approach for robust controller (RC) design for Electro-magnetic Levitation System (EMLS) in delta domain. Dynamic systems modelling with delta operator provides a unified framework in rapprochement between discrete-time dynamic models and its continuous counterpart at fast sampling. This property is utilised to design different classical control schemes such as PI, PD and PID in delta domain for EMLS. Generally, the behaviour of the EMLS is nonlinear and it is unstable in nature. Due to the above properties it is first linearised. The controllers are designed in delta domain such that both the physical systems of EMLS (voltage and current controlled systems) become robust subject to all parameter variations and uncertainties. The simulation results exhibit the usefulness of the proposed controller design methodology.

In this paper, sensorless magnetic levitation for large air gap translational motion is investigated. Most of the research in this field has been for magnetic bearings whose system characteristics and control requirements are different from a translational moving vehicle. An obvious difference is the range of operational air gap. Furthermore, the quality of magnetic materials, in terms of laminations, saturation, etc. used is also different. Therefore, well developed sensorless methods for magnetic bearings cannot be directly applied to large air gap applications. Thus, a novel method is proposed for detecting air gap by injecting high frequency signal into the magnetic coil and measuring either rising or falling current-ripple slope (single slope detection) using high speed sampler. Resistance is simultaneously estimated as well. Finally, stable levitation using the detected air gap signal as control feedback is demonstrated experimentally.

The gravimeter is highly demanded to improve the accuracy of a navigation system. So we designed and fabricated a relative gravimeter featuring a superconducting planar spring and the electromagnetic levitation. The advantages of a superconductor enable the device to be with exceptional stability and have the extremely low noise. The coupling spring with the electromagnetic levitation can also offer a low resonant frequency for the high sensitivity. It consists of a Niobium vibrometer with a single planar spring, a levitation coil, and a SQUID (Superconducting Quantum Interference Device) sensor. We optimized the design parameters through mathematical analysis and mechanical-electromagnetic FEM simulations. EDM and a high vacuum-thermal process are applied to fabricate superconducting structures. Some experiments storing and discharging a persistent current are carried out at 4.2K cryogenic condition, confirming the numerical predictions.

In this paper a practical demonstration for simultaneous levitation and rotation for a ferromagnetic object is presented. A hollow steel cylinder of 59 gm mass is arranged to remain suspended stably under I-core electromagnet utilizing DC electromagnetic levitation principle and then arranged to rotate the levitated cylinder around 1000 rpm speed based on eddy current based energy meter principle. Since the object is to be rotating during levitated condition the device will be frictionless, energy-efficient and robust. This technology may be applied to frictionless energy meter, wind turbine, machine tool applications, precision instruments and many other devices where easy energy-efficient stable rotation will be required. The cascade lead compensation control scheme has been applied for stabilization of unstable levitation system.

In this paper the analysis, design and fabrication of 3-coil based DC attraction type levitation scheme has been presented. In vehicle applications majority works have been reported based on four actuators based electromagnetic levitation system (EMLS). But in this prototype three electromagnets have been used at the three sides of the platform. The use of one magnet-coil, power amplifier and associated gate driver, controller circuit, position and current sensor is dispensed with the prototype. So there is considerable reduction of cost and weight of the proposed system and the hardware circuit is also simpler than four-coil structure. The objective is to levitate a platform under ferromagnetic guide-way normally used in electromagnetically levitated vehicle structure. The prototype (total mass 7.528kg) consists of three identical electromagnets placed at the three sides of a platform and the structure is made to remain suspended at different air-gap positions under a ferromagnetic guide-way - the arrangement that is normally used for EMLS. The structure of the levitated system has been constructed in-house. The three actuators have been controlled simultaneously by three similar single input single output (SISO) controllers utilizing the cascade Lead compensation control scheme. The design and implementation of the controller for such an unstable and non-linear system is the main aim of this study. The stable levitation has been demonstrated of the platform around an operating point.

A novel second-order sliding model controller aiming at the inherent chattering of classical sliding mode control for high-precision air gap control of Electromagnetic Levitation Grip used in CNC(Computerized Numerical Control) was proposed, and the control strategies based on super-twisting algorithm was designed. Electromagnetic Levitation Grip is a very complex system with real parameter uncertainties and external disturbances in the process of air gap control. This method can eliminate the chattering which may excite high frequency chattering, keep the robustness of system, and effectively improve the dynamic response of system. Simulation results demonstrate that the design of Second-order sliding mode controller can achieve the better stability of suspension, strong immunity and high stiffness.

This paper describes the three-dimensional motion control of a magnetic levitated object in an active electromagnetic levitation conveyance system. Generally, the magnetic levitation conveyance system is useful when we convey products without qualitative degradation due to contact. However it is necessary to control the three-dimensional motion of the levitated object and it is difficult to measure the position. Therefore we propose how to estimate three-dimensional position without a position sensor. Four Hall elements are installed on the bottom of the electromagnet instead of the position sensor. A state observer estimates the three-dimensional position of the levitated object from the four Hall voltages and the current and the input voltage to the electromagnet. The three-dimensional motion controller uses a state-feedback control based on the estimated position. This controller has a large stability margin in order to compensate the modelization error. The validity of the proposed method is confirmed by experiment results.

An electromagnetic levitation platform for use in a light emitting diode (LED) arena based virtual reality environment was developed for wireless recording of neural and neuromuscular signals from the flight related muscle groups in Manduca sexta. The platform incorporates the use of Early Metamorphosis Insertion Technology to implant recording electrodes into the flight muscles of late stage pupal moths. Analysis of the insects' response to changes in the LED arena rotation direction indicate that this setup could be used to perform a variety of flight behavior studies during yaw maneuvers.

This paper presents a linear model for self-sensing electromagnetic levitation system. We consider one degree of freedom magnetic levitation system composed of a suspended object and an electromagnet driven by a pulse-width-modulation amplifier. The proposed model makes use of the airgap information contained in the derivative of the coil current. We design a controller based on the proposed model, and show that the system performs well by using computer simulation.

In this paper the optimized parameters of Lag-Lead and Proportional Integral Derivative (PID) controller for two-actuator based electromagnetic levitation system (EMLS) are determined using Evolutionary computation algorithms such as Particle Swarm Optimization (PSO) and a novel Gravitational Search algorithm (GSA). A comparative position response of EMLS (Electro Magnetic Levitation System) with classical, GSA and PSO based nominal controllers while operating at nominal and off-nominal (low and high) air-gaps have been studied. It is seen that GSA based optimized nominal PID controller shows excellent performance (both in transient and steady-state) over a large operating air-gap. The experimental results with the classical controller are also presented.

In this paper an overview of power amplifier for multi-magnet based DC electromagnetic levitation system has been presented. The general requirement of power amplifier for levitation system has been described. The proposed multi-magnet based single axis levitation scheme has been described in brief. Different possible switched mode power circuits for the multi-magnet based electromagnetic levitation system have been discussed and a comparative study has been made of the different topologies of power amplifiers based on their structure and practical results that derived from the proposed experimental set-up. In the actual work design, fabrication and testing of multi- magnet based electromagnetic levitation scheme has been made as a complete project. But in this paper the emphasis is given on the power amplifier portion due to limitation of space.

Systems which involve electromagnetic interactions are very difficult to model. Often, when developing controllers for such systems the model which is used is affected by uncertainties or is linearized. Even if these models can be used for the controller design process, they are not well suited for accurate simulations. In this paper, an electromagnetic levitation system is modeled. Based on the observed behavior of the system, a neural network is used to approximate a non-linear parameter in the model of the plant, which otherwise would have been very difficult to model.

The levitation rigidity for the levitated crossbeam of the gantry numerical control machine tool which can eliminate friction and increase machining precision is discussed. The feedback linearization and sliding mode control methods are presented in this paper in order to achieve steady levitation. The nonlinear electromagnetic levitation system is transformed into linear system by using feedback linearization method. The sliding mode control method is adopted for improving the robustness of the levitation system. Simulation results show that the system has more powerful ability of suppressing disturbance and high rigidity compared with that using conventional PI control method.

Electromagnetic levitation system (EMLS) is inherently unstable and strongly nonlinear in nature. A cascade lead compensation control scheme utilizing inner current loop and outer position loop has been designed and implemented for stabilization of a single magnet based single axis levitation system. The prototype has been successfully tested and stable levitation has been demonstrated at the desired operating gap. The dynamic performance of the controller has been studied experimentally by applying different disturbance inputs (square wave, sinusoidal etc.) with increasing magnitudes and frequencies. The effect of different basic parameters of the levitation system on the performance of the designed controller has also been observed.

This article builds a mathematical model of electromagnetic suspension system in the large air gap, and analyses the features of suspension system precisely through finite element analysis, calculates the electromagnetic force size which the suspended matter in the system received. Finally gave the experimental data a Curve fitting by the method of least squares, result in a fitting expression in the large air gap.

In this paper an attempt has made for stable suspension of a cylindrical rod under two electromagnets controlling different degrees of freedom movement. The two actuators are controlled independently through two identical controllers and the stable levitation of the rod is achieved through single input and single output (SISO) control of each air-gap corner. The focus is on to design and development of controller unit for two actuators. The proposed single switch based power circuit simplifies the overall hardware and it can be extended to any number of magnet-coil. A cascade lead-lag compensation control scheme utilizing inner current loop and outer position loop has been designed and implemented for stabilization of such highly unstable and strongly non-linear system. The prototype has been successfully tested and stable levitation was demonstrated at the desired operating gap.

For the mobile beam suspension height of gantry CNC machining center. In order to eliminate influence of friction, improve machine precision, this paper adopt maglev technology to suspension beam. In this paper, mathematical model of gantry beam suspension system is established, and then a self-tuning quantization scale factor fuzzy controller is designed. The fuzzy controller can real-time adjust quantification factors and scaling factor, and improve suspension precision, then flexible control to the whole system is achieved. At the same time, disturbance observer is designed to observe the external disturbance and model uncertainties. Then the equivalent output which was observed is sent to the control input, to achieve interference suppression. The simulation results show: this control scheme is applied to control the suspension beam, the system has good performance of anti-interference and high stiffness. The Beam can be stable suspension without friction.

We have proposed a magnetic levitation control system for flexible steel plates and confirmed its feasibility through a digital control experiment. However, there is a risk that side slipping or the dropping of the plate may occur owing to inertial force, because the levitation control system does not provide any restraints for the direction of travel. Therefore, we have proposed the addition of electromagnetic actuators to control the horizontal motion of a levitated steel plate. In addition, we have reported that it is possible to suppress the elastic vibration of the steel plate in the vertical direction by using the electromagnetic actuators for horizontal positioning. In this paper, the effect of the magnetic field applied from the horizontal direction on the transport performance of a magnetically levitated flexible steel plate is reported.

This paper describes an electromagnetic levitation experience developed at UFRJ using the real-time control toolbox available with MATLAB. This work shows the model used in the position control of a steel ball, the control design procedure and the prototype. The main application of this experience was focused in the vertical position control of a Maglev train system, also researched at LIFRJ.

Filter is a part to degrade the noise during designing electric circuit, it is seldom considered during controlling system design. But it will greatly influence the stability of system. In this paper, the stability of PD controller without filter is analyzed. The oscillation condition and oscillation frequency are given. Simulation validates the results. Subsequently the velocity filter is involved and the relationship between the filter parameter and velocity feedback gain is brought up. The result is given by graph after digital calculation and corrects the region of PID controller, which stabilizes the levitation system.