Electromagnetic Levitation System Research Articles

Constrained control for electromagnetic levitation system with matched and mismatched uncertainties via robust optimal design

Constrained control for electromagnetic levitation system with matched and mismatched uncertainties via robust optimal design

Robust-optimal control design for current-controlled electromagnetic levitation system with unmatched input uncertainty

Robust-optimal control design for current-controlled electromagnetic levitation system with unmatched input uncertainty

Performance Optimization of Maglev Train’s Electromagnetic Levitation System: Control Structure and Algorithm

This article investigates the performance optimization structure and algorithm of the electromagnetic levitation (EML) system. Firstly, a functionalized control structure is proposed by the incremental attachment of a controller gain system. Under this control structure, the predesigned controller is designed for nominal performance while the controller gain system handles performance optimization. This is of great help because the system trajectory of the highly dynamic and open-loop unstable EML system can be contained in the admissible region during the optimization of the controller gain system. Secondly, it is demonstrated that optimizing the incrementally attached controller gain system (under the proposed control structure) for performance optimization is equivalent to optimizing the predesigned controller. The advantage of the equivalence is that the predesigned control system needs not to be modified and the incremental attachment can be performed even when the EML system is running. Furthermore, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> -learning algorithm is presented for the real-time implementation of the proposed structure and the incrementally attached controller gain system. Finally, the effectiveness of the structure and algorithm is validated on the EML system. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —The EML system is key to maglev transportation. It is open-loop unstable, highly dynamic, and its accurate model is generally unavailable. On the other hand, the levitation performance may not be optimal given the predesigned controller. Moreover, during the long-term operation, it is desired in practice that the controller of EML system can be upgraded in a friendly fashion. This article presents a control structure that optimizes the levitation performance in an incremental style, such that the predesigned controller does not need to be modified. The incremental attachment can be realized via the onboard CAN network or UDP channel. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> -learning algorithm optimizes the incrementally attached controller gain system without distabilizing the levitation stability of the EML system under the proposed control structure. In such a way, the open-loop and highly dynamic characteristics can be handled and the friendly implementation style can be achieved.

A study on attraction type electromagnetic levitation systems for four different shaped objects

A study on attraction type electromagnetic levitation systems for four different shaped objects

A study on attraction type electromagnetic levitation systems for four different shaped objects

A study on attraction type electromagnetic levitation systems for four different shaped objects

Adaptive dynamic programming discrete‐time LQR control on electromagnetic levitation system

AbstractIn this paper, an adaptive dynamic programming discrete‐time linear quadratic Riccati (ADP‐DTLQR) control is designed for an electromagnetic levitation system (EMS) to track the reference trajectories and preserve stability in severe situations efficiently. The EMS system has a strongly nonlinear and unstable dynamic in nature. The ADP‐DTLQR approach is a novel method based on the Q‐learning algorithm for unknown discrete‐time systems in a causal manner. The ADP‐DTLQR can determine the online gains of the controller in different conditions as a model‐free structure, which can minimize the combination of state errors and control efforts of the systems. Moreover, the DTLQR controller and linear matrix inequality controller on the EMS system are designed and compared with the present strategy in different scenarios in the simulation section to verify the robustness and strongness of the proposed method. The evaluation of simulation results demonstrates that the proposed control scheme is suitable not only for preserving the levitated object stability but also for compensating the disturbances and uncertainties in the EMS structure.

Adaptive dynamic programming discrete-time LQR optimal control on electromagnetic levitation system with a $$H_\infty $$ Kalman filter

Adaptive dynamic programming discrete-time LQR optimal control on electromagnetic levitation system with a $$H_\infty $$ Kalman filter

Performance optimization of electromagnetic levitation system based on gradient estimator

Aiming at the problem of optimal design of the controller of electromagnetic levitation system, this paper proposes a gradient estimator-based controller design and optimization structure suitable for electromagnetic levitation system. The structure consists of a nominal controller, a residual generator, and a dynamic compensator. The controller structure can further improve the anti-disturbance and robustness of the electromagnetic levitation system on the premise of ensuring the stability and reliability. Considering the generality of electromagnetic levitation system, the proportional–integral–derivative (PID) controller is selected as the nominal controller, and the robustness of the system is improved by the dynamic compensator based on the residual generator. The parameter design and update strategy of dynamic compensator based on gradient estimator are proposed, and the expression of gradient estimator is designed and deduced. Taking the single-degree-freedom electromagnetic levitation experimental platform as an example, the simulation and experimental results show that the structure has strong robustness to shock disturbances. Compared with the PID controller, the range of the gap fluctuation is smaller after the instantaneous impact interference, and the anti-interference capability of the electromagnetic levitation system is improved.

Adaptive Fixed-Time Antilock Control of Levitation System of High-Speed Maglev Train

Due to electromagnet uncertainties, rail irregularities and other external disturbances, an excessively small levitation gap of electromagnetic levitation system (EMLS) may lead to serious deadlock, which would severely endanger the operational safety of high-speed maglev trains. A highly reliable levitation controller must be designed with the inherent antilock capability to prevent such fatal deadlock. In this work, an adaptive fixed-time levitation control scheme is established by directly introducing antilock limits of EMLS into an output-constrained controller, by which not only the desired levitation distance is achieved with a fixed-time convergence rate, but also the EMLS never exceeds the predefined levitation boundaries. Therefore, the antilock levitation operation is naturally ensured. Both theoretical analysis and numerical simulations verify the effectiveness of the proposed control method.

Development of Electromagnetic Levitation System for Thin Steel Plates with Electromagnets and Permanent Magnets for Levitation Support (Experimental Consideration of Vibration Characteristics of Levitated Steel Plates)

Development of Electromagnetic Levitation System for Thin Steel Plates with Electromagnets and Permanent Magnets for Levitation Support (Experimental Consideration of Vibration Characteristics of Levitated Steel Plates)

Design, testing and implementation of a linear state variable feedback controller for providing tracking/regulation of a large platform of a Maglev vehicle

The basic parameters of an electromagnetic levitation systems are resistance of the coil, inductance of the coil, air-gap between magnet and the object, coil current, mass of the object, controller parameters and so on. The levitation systems are highly unstable and strongly non-linear. In real-life applications, these parameters are supposed to vary. A proportional–integral controller for the inner current control loop and a lead compensator for the position control loop have been designed and tested. The performance study under various parametric effects has been investigated broadly. Finally, both the stability for the proposed levitation system has been achieved with a better operating zone using linear state variable feedback controllers. The system dynamic performances have been recorded for variations of physical system parameters. The sensitivity/robustness of the set-up has been studied. This study will give an insight for designing any corrective measures and an overall idea to develop a levitation system.

Real-Time Performance Optimization of Electromagnetic Levitation Systems and the Experimental Validation

The electromagnetic levitation (EML) system serves as a key subsystem in maglev trains for the purpose of levitation. It is highly dynamic, open-loop unstable, and safety-critical. The expense of establishing an accurate model out of the Maglev train, in addition to the varying operating conditions, results in an imperfectly known model in engineering practice. Thus high-performance levitation control, w.r.t. an imperfectly known model, is of considerable practical interest. Motivated by such an observation, this article investigates real-time levitation performance optimization of the EML system, with an imperfectly known model. The EML system is first modeled and an equivalent demonstration benchmark is developed. Then, the structure for levitation performance optimization is presented on top of the coprime factorization technique. Furthermore, the real-time levitation performance optimization algorithm is developed, utilizing only the input and output data. In the end, the proposed methods are validated on the benchmark.

Measurement of the Normal Spectral Emissivity of Molten Oxide Using an Electromagnetically Levitated Complex Droplet of Molten Oxide and Liquid Fe

We proposed the determination method of the normal spectral emissivity of molten oxides using a combination of immiscible molten oxides and liquid metals. We can determine the normal spectral emissivity of molten oxide from the ratio of the normal spectral radiance of molten oxides andliquid metals, using a commercially available pyrometer combined with an electromagnetic levitation system. In the present study, we measured the normal spectral emissivity of a molten oxide sample from SiO2-CaOFeO (SCF) ternary system and FeO using liquid Fe as the reference liquid metal. The normal spectral emissivity of the molten SCF sample with the composition of SiO2:CaO:FeO = 20:20:60 mass % was determined to be 0.78±0.01 and that of molten FeO to be 0.68 ± 0.03. Based on these results, we have discussed the relationship between the normal spectral emissivity and the electrical conductivity of molten oxides.

Comprehensive review and analysis of the electromagnetic levitation systems (modeling, controllers, nonlinearity sources)

Magnetic Levitation Systems (MLS) is a higher advanced technology without any mechanical contact that results in zero friction losses. Such technology offers a low cost of maintenance, precise operation, very clean working, not noisy and quiet, remotely controlled, and small size. These features make it utilize with various important applications in different fields and different industries sectors, it can be applied in the vibration absorber, Biomedical applications or devices, very fast transport technology, etc. It is very well known that the (MLS) are non-linear and unstable open-loop, hence, numerous approaches are considered for non-linear control techniques to present a variety of results. The aim of our analysis in this article is to introduce the system's nature and behavior and to learn about the system's components as well as to cover most of the applied controlling approaches that were suggested by researchers to acquire the best performance.

Design and Analysis of Guidance Function of Permanent Magnet Electrodynamic Suspension

Inspired by the guidance principle in the electromagnetic levitation system, a new permanent magnet electrodynamic suspension (PM EDS) structure with ferromagnetic guidance track is proposed and analyzed in this paper. Considering the lack of effective guidance ability for the PM EDS system, we adopted the ferromagnetic guidance track as being mounted under the conductor plate. The guidance principle is studied and the implementation of the guidance function is also introduced, and the finite element method (FEM) is employed and its accuracy is confirmed via the PM EDS high-speed rotating experimental platform fabricated in our laboratory. The influence of longitudinal speed on the guidance force is taken into account, which shows that the guidance performance is enhanced more obviously at low speeds. Moreover, the influence of the guidance track parameters on the guidance performance is also analyzed, including the geometric parameters, section shape, installation position and material. The equivalent small-scale PM EDS system experimental prototype is carried out to validate the effectiveness of the ferromagnetic guidance. The proposed ferromagnetic guidance structure is demonstrated to improve the guidance performance of the PM EDS system effectively, which will offer a technical reference for the practical engineering application of the PM EDS system.

Vibration Characteristics of Flexible Steel Plate on Proposed Magnetic Levitation System Using Gravity

Flexible steel plates are generally transported by rollers; however, the contact between the rollers and the steel plate degrades the surface quality of the plate. To solve this problem, noncontact transportation of steel plates using electromagnetic force has been proposed. However, ultrathin flexible steel plates can easily fall owing to deflection. A magnetic levitation system using electromagnets installed in the horizontal direction has also been proposed to improve the levitation performance of a conventional system. However, it is difficult to control vibrations with such a system because flexible steel plates are elastically deformed into complex shapes by gravity. Therefore, an electromagnetic levitation system was proposed, wherein electromagnets were installed near the edge of the steel plate such that it could be controlled with noncontact grip, such as by allowing one side of the steel plate to hang. This system is expected to improve levitation stability because the moment of inertia increases with vertical levitation and simplifies the control system. In addition, this system actively uses gravity acting on a steel plate to decrease its deflection. The use of gravity to suppress deflection is novel. In this study, the feasibility of magnetic levitation using the proposed system was investigated using magnetic field analysis. Its usefulness was investigated experimentally using a constructed magnetic levitation system. In addition, it was found that a magnetic levitation system that maintains the standing position generates a peculiar vibration.

Experimental Consideration on Suppression Effect of Elastic Vibration in Electromagnetic Levitation System for Flexible Thin Steel Plate with Curvature

Recently, research on non-contact conveyance systems using electromagnetic levitation technology has accelerated. We have constructed an electromagnetic levitation control system that keeps the relative distance between the electromagnet and steel plate constant. To investigate the levitation stability of thin steel plates, we performed magnetic levitation experiments on a thin steel plate with curvature. A physical disturbance was applied to the electromagnet units by vibrators. The electromagnet units were vibrated up and down by a vibrator. We investigated whether the bending magnetic levitation improved the levitation performance even if the magnetic levitation system was in a vibrating environment. We determined that it was possible to realize stable levitation for a steel plate under external disturbances during levitation at the optimal bending angle.

Control techniques for electromagnetic levitation system: a literature review

Control techniques for electromagnetic levitation system: a literature review

Adaptive control of nonlinear plant with unmatched parametric uncertainties and input saturation

The problem of adaptive control of a parametrically uncertain nonlinear plant presented in a state-feedback form with unmatched uncertainties and input constraint is considered. The solution is based on adaptive backstepping procedure, in which the virtual controls includes the high-order time derivatives of adjustable parameters calculated with the use of an adaptation algorithm with improved parametric convergence. Analytical design of control with compensation for the influence of input constraints is performed using of a special filter. The approach presented in this paper allows one to design an adaptive controller that ensures the boundedness for all signals in the closed-loop system and provides tracking of the reference signal. Simulation results presented in the MATLAB/Simulink environment illustrate the performance of the presented approach and the acceleration of parametric convergence with an increase of the adaptation coefficient. The plant considered in this work describes a wide class of systems, such as various manipulation robots, technological processes, electromagnetic levitation systems, chemical processes, etc. The proposed control algorithm considers natural for practical applications input constraints and significantly reduces the influence of the regulator parameters tuning speed on the control system transient processes.

Design of a coil for electromagnetic levitation: comparison of numerical models and coil realization

Electromagnetic levitation is a unique environment allowing for making non-contact measurements over samples of liquid metals at different temperatures. The electromagnetic coil is the core of the electromagnetic levitation system, and its design defines the amount of energy introduced into the sample as well as the shape and stability of the latter during levitation. In the present work, analytical and numerical modelling for a real electromagnetic inductor is performed and compared with experimental observations. The shape of the experimental electromagnetic coil is assured due to 3D printing of a template which is used for the coil winding. Tables 3, Figs 5, Refs 14.