Air Gap Control Research Articles

Modeling of novel cross-type hybrid 4-pole carrier system and experimental air gap control

PurposeThe purpose of this paper is to introduce a novel cross (+) type yoke with hybrid electromagnets and new reluctance modeling to precisely calculate attraction force is given.Design/methodology/approachThe comparison of attraction force and torque analyses between the proposed formulation and the existing formulation in the literature is comparatively presented. For the correctness of the force and torque values calculated in the model created, the system was created in ANSYS Maxwell and its accuracy was proved by making analyses. The maglev carrier system is inherently unstable from the point of view of control engineering. For that, it needs an active controller to eliminate this instability. For the levitation of the carrier system, it is necessary to design a controller in three axes (z, α and β). I-PD controller was designed for the air gap control of the carrier system in three axes and the controller parameters were determined by the canonical method.FindingsWhile the new formulation proposed in the modeling of the carrier system has a maximum error of 1.03%, the existing formula in the literature has an error of 16.83% in the levitation distance point.Originality/valueA novel cross-type hybrid carrier system has been proposed in the literature. With the double integral used in modeling the system, it takes a long time to solve symbolically, and it is difficult to simulate dynamic behavior in control validation. To solve this problem, attraction force and inclination torque values are easily characterized by new formulation and besides the simulations are conducted easily. The experimental setup was manufactured and assembled, and the carrier system was successfully levitated, and reference tracking was performed without overshoot.

PID controller enhanced with artificial bee colony algorithm for active magnetic bearing

To reduce the effect of non-linearity in air gap control in active magnetic bearings (AMB). The PID controller for the AMB is proposed in this study, which is optimized with a reformative artificial bee colony (RABC) algorithm. The RABC algorithm balances the exploitation and exploration capabilities of the ABC algorithm by introducing globally optimal solutions and improved food source probabilities. Simulation with six benchmark functions validates the proposed algorithm, and the results reveal that the RABC algorithm has higher search accuracy and faster search speed than previous ABC algorithm versions. The experimental results show that RABC-PID outperforms the other four approaches and has greater robustness when compared to traditional PID, PSO-PID, DE-PID, and GA-PID. Meanwhile, the RABC-PID controller makes the AMB system more stable.

Performance of Urban Water-Pipeline Energy Harvester System Considering Electromagnetic-Mechanical Design

This paper proposesthe design process and performance of an Urban Water-pipeline Energy Harvester (UWEH) System. The UWEH system design is broadly divided into two parts, namely, the electromagnetic and mechanical subsections modeling. The electromagnetic modeling includes the selection, design, prototyping and performance testing of a 65-kW permanent magnet synchronous generator (PMSG) which runs at the rated speed of 500 rpm. The mechanical modeling includes the installation, bearing selection, propeller system integration and waterproof sealing mechanism of the whole UWEH system for the field test. Detailed information on practical implementation is highlighted. Finally, based on the lessons learned from the problem associated with the mechanical subsection, a bearing-less buoyant rotor mechanism is proposed explaining its airgap control mechanism.

Influence of Adaptive Gap Control Mechanism and Tool Electrodes on Machining Titanium (Ti-6Al-4V) Alloy in EDM Process.

Titanium alloy is widely used for orthodontic technology and easily machined using the EDM process. In the EDM process, the workpiece and tool electrode must be separated by a continuous air gap during the machining operation to generate discharge energy in this method. In the present study, an endeavor was made to analyze the effects of a servo feed air gap control and tool electrode in the EDM process. The developed mechanical setup consists of a linear action movement with zero backlash along the X-axis, which can be controlled up to 0.03 mm. It was observed that the suggested air gap control scheme can enhance the servo feed mechanism on a machining titanium alloy. A tungsten carbide electrode can enhance the surface measures owing to its ability to produce tiny craters with uniform distribution. Since it produces a little crater and has a higher melting point, a tungsten carbide electrode can create lesser surface roughness than a copper tool and brass tool electrode.

Control of Time Delay in Magnetic Levitation Systems

The high-performance control of magnetic levitation (maglev) vehicles has encountered challenges in the form of time delays. In this letter, we model a reliable control method based on a Takagi-Sugeno fuzzy model aimed at solving the problem of air gap control of a magnetic levitation system for a maglev vehicle under time-delay conditions. The key idea is based on the global fuzzy model derived through sector nonlinearity to design a global controller utilizing the parallel distributed compensation method and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${H_\infty }$</tex-math></inline-formula> method. As a result, the stability of the system is guaranteed under conditions of mass parameter uncertainty, disturbance, and time delay. The theoretical analysis, numerical simulations, and experimental results consistently show the effectiveness of the control method.

Control and Operation of a Hybrid Actuator for Maglev Applications

Abstract The hybrid actuator presented in this article is meant to enable stationary and slow dynamic levitation in Maglev applications. The term ‘hybrid’ refers to the design of the actuator, which is a combination of permanent magnets (PM) and electromagnets. This paper presents an analytically computable control algorithm for the said hybrid actuator. The theory of magnetic circuits is summarized shortly and used to derive a cascaded control loop consisting of an inner current controller and an outer air gap controller. Since the uncontrolled hybrid actuator is inherently unstable, the system has to be stabilized. By introducing a PID-controller into the air gap control loop, the unstable behaviour of the uncontrolled system is changed into the system behaviour of a damped harmonic oscillator. The advantage of this approach is that the computed controller parameters of the PID-controller can easily be adjusted, so the system behaviour of damping and eigenfrequency can be selected within a certain range. For the execution of the control algorithm, a microcontroller (MCU) is used and for precise air gap measurement, an eddy current sensor is installed. Finally, the behaviour of the current- and air gap controller is discussed for different measurement results and the adjustable system behaviour of the damped harmonic oscillator is presented.

A homogeneous extended state estimator-based super-twisting sliding mode compensator for matched and unmatched uncertainties

In this research work, an output tracking problem of a kind of nonlinear motion control systems influenced by exogenous uncertainties using second-order super-twisting sliding mode control is studied. It is shown that when second-order super-twisting sliding mode control is implemented with finite-time convergent homogeneous extended state observer, the second-order sliding mode is achieved on the selected sliding manifold with efficient disturbance attenuation from the output. The presented control structure is tested on the air-gap control of an electromagnetic levitation suspension system using MATLAB platform. The observations prove the efficacy of the proposed algorithm providing excellent robust control efficiency along with precise attenuation of various disturbances.

Model predictive control of a magnetic levitation system using two-level state feedback

The magnetic levitation system is a critical part to guarantee safe and reliable operations of a maglev train. In this paper, the control strategy is proposed for the magnetic levitation system based on the model predictive control incorporating two-level state feedback. Taking advantage of the measurable state variables, that is, air gap, electromagnet acceleration, and control current through high-resolution sensor measurement, the first-level nonlinear state feedback is to linearize the unstable nonlinear magnetic levitation system, and the second-level linear state feedback is to further stabilize the system and improve the dynamic performances, which together provide a stable prediction model. The simulation results demonstrate that the proposed control strategy can ensure high-precision air gap control and favorable disturbance resistance ability.

Analysis of Quasi-Zero Power Characteristic for a Permanent Magnetic Levitation System with a Variable Flux Path Control Mechanism

This article focuses on the analysis of the quasi-zero power characteristic for a permanent magnetic levitation system with a variable flux path control mechanism. The system mainly consists of a disk permanent magnet, a pair of yokes, and a rotary actuator. The permanent magnet magnetized diametrically is rotated by the actuator, which can achieve the control of the levitation force by changing the flux. Unlike the electromagnetic system, the input to the actuator is used to maintain the rotation angle corresponding to the equilibrium position, not to directly produce a magnetic force. Therefore, the proposed system possesses a lower power consumption. Analysis of mechanism, current model, and different levitation control strategies are presented in this article. With the variable air gap length control and the constant air gap length control, the permanent magnetic levitation system performs well in levitation with quasi-zero power in loading experiments. The constant air gap control is demonstrated to possess higher safety when the levitation mass is changed, which has the potential for magnetic levitation transportation.

МОДЕЛИРОВАНИЕ ГИБРИДНОГО ЭЛЕКТРОМАГНИТНОГО ПОДВЕСА ДЛЯ ВЫСОКОСКОРОСТНОГО ВАКУУМНОГО ТРАНСПОРТА

A hybrid electromagnetic hanger is presented for high-speed vacuum transport means where a main force of levitation is created at the expense of constant magnets and an electromagnet performs air gap control. There is developed a computer model in MATLAB/Simulink program complex which allows carrying out the dynamic mode simulation of a system work. The simulation of transport means acceleration up to 1000 km/h taking into account road irregularities is carried out.

Internet of Things-Based Online Condition Monitor and Improved Adaptive Fuzzy Control for a Medium-Low-Speed Maglev Train System

The maglev rail transit has entered a rapid development stage. In order to prevent potential safety hazards in the operation of maglev train, the related monitoring technology needs to be studied urgently. In this article, in view of the wide application of the Internet of Things (IoT) in intelligent transportation, a new method for realizing suspension control for medium-low-speed maglev trains using the IoT and an adaptive fuzzy controller is proposed. First, a mathematical model of the suspension system of medium-low-speed maglev trains is established. Then, the basic composition of the IoT and the circuit design of the key components of maglev trains are introduced. On this basis, an improved Apriori algorithm is used to extract the stored historical database and establish a trusted database. Then, according to the data of the trusted database, the suspension airgap control law is extracted, and the adaptive fuzzy rules of the maglev train suspension system are determined. An improved adaptive suspension controller is designed. Finally, the effectiveness of the method is verified by experiments utilizing a full-scale maglev train.

Design and Fabrication of an Experimental Microheater Array Powder Sintering Printer

Microheater array powder sintering (MAPS) is a novel additive manufacturing process that uses an array of microheaters to selectively sinter powder particles. MAPS shows great promise as a new method of printing flexible electronics by enabling digital curing of conductive inks on a variety of substrates. For MAPS to work effectively, a microscale air gap needs to be maintained between the heater array and the conductive ink. In this article, we present an experimental MAPS printer with air gap control for printing conductive circuits. First, we discuss design aspects necessary to implement MAPS. An analysis is performed to validate that the design can maintain the desired air gap between the microheaters and the sintering layer, which consists of a silver nanoparticle ink. The printer is tested by printing conductive lines on a flexible plastic substrate with silver nanoparticle ink. Results show MAPS performs on par with or better than the existing fabrication methods for printed electronics in terms of both the print quality (conductivity of the printed line) and print speed, which shows MAPS’ great promise as a competitive new method for digital production of printed electronics.

Microheater array powder sintering: A novel additive manufacturing process

One of the most versatile additive manufacturing (AM) processes is selective laser sintering (SLS), which scans a powder bed with a laser beam to fuse powder particles layer by layer to build 3D objects for prototypes and end products with a wide range of materials. However, it suffers from slow printing speed due to the pointwise scanning and high energy consumption due to the requirement of a high-power laser. In this paper, we propose a novel method of additive manufacturing which replaces the laser beam with an array of microheaters as an energy source to sinter powder particles. This method, referred to as Microheater Array Powder Sintering (MAPS), has the potential to significantly increase the printing speed by layer-wise sintering and reduce the power consumption due to the lower power requirements of the microheater array. This paper is to provide a proof-of-concept for this proposed new method. First, a thin-film microheater was designed and simulated with an experimentally validated numerical model to demonstrate that it can be used as an alternative energy source to sinter powder particles by reaching a target temperature of 600 °C within milliseconds at a power consumption of 1.2 Watts. The numerical model was used to simulate the MAPS process by placing the heater in close proximity to the powder particles. Simulation results showed that heat can be effectively transferred over an airgap to raise the temperature of the powder particles to their sintering temperature. Different process parameters (e.g., airgap, material properties, time, printing resolution, etc.) are discussed. An experimental MAPS system was then implemented to provide a proof-of-concept with the designed microheater and a custom airgap control apparatus. A straight line was successfully printed on thermal paper using the experimental MAPS system, which suggests the proposed MAPS process is feasible.

Design and demonstration of a flexible matrix composite morphing control surface for air gap control in a Fowler flap

A full-scale commercial aircraft morphing control surface using flexible matrix composite actuators was designed and demonstrated in this research. The muscle-like flexible matrix composite actuator is ideal for morphing structures as it deforms while actuating with the structure, and the hydraulically driven actuator can operate at pressures similar to existing aircraft hydraulic systems. Through a series of parameter studies performed with finite element models, an active spoiler was designed to control the gap between a spoiler and deployed Fowler flap. A full-scale prototype was then fabricated and tested under pseudo-aerodynamic loads. The prototype demonstrated that it can achieve the necessary deflections under the given loading condition. A closed-loop control system that allows the tip deflection of the spoiler to be precisely controlled under loading was designed.

Wide Air-gap Control for Multi-module Permanent Magnet Linear Synchronous Motors without Magnetic Levitation Windings

This paper proposes a wide air-gap control method for the multi-module permanent magnet linear synchronous motor (MM-PMLSM) based on independent vector control. In particular, the MM-PMLSM consists of symmetrical multi-module and multi-phase structures, which are basically three-phase configurations without a neutral point, unlike conventional three-phase machines. In addition, there are no additional magnetic levitation windings to control the normal force of the air-gap between each stator and mover. Hence, in this paper, a dq-axis current control applying a d-q transformation and an independent vector control are proposed for the air-gap control between the two symmetric stators and mover of the MM-PMLSM. The characteristics and control performance of the MM-PMLSM are analyzed under the concept of vector control. As a result, the proposed method is easily implemented without additional windings to control the air-gap and the mover position. The effectiveness of the proposed independent vector control algorithm is verified through experimental results.

Dynamic Interaction Analysis between Maglev Train with Airgap Control Algorithm Based on Acceleration Feedback and Guideway

Dynamic Interaction Analysis between Maglev Train with Airgap Control Algorithm Based on Acceleration Feedback and Guideway

Magnetic Bearing Spindle Tool Tracking Through &lt;inline-formula&gt;&lt;tex-math&gt;${\mu}$&lt;/tex-math&gt; &lt;/inline-formula&gt;-Synthesis Robust Control

A method is presented for tooltip tracking in active magnetic bearing (AMB) spindle applications. The proposed tool tracking approach uses control of the AMB air gap to achieve the desired tool position. A μ-synthesis-based controller is designed for the AMBs with the goal of robustly minimizing the difference between the tool reference and estimated tool position. In such a way, the model-based control approach concurrently addresses the tracking problem and the inability to directly measure real-time tool position in the presence of machining disturbances. To ensure the tractability of the control problem, a model of the desired tracking dynamics is included in the plant. The method is demonstrated on a high-speed AMB boring spindle. To confirm the tool tracking capability, characteristic part geometries are traced including stepped, tapered, and convex profiles. Tool tracking is demonstrated for the rotating AMB spindle in the range of 90 μm. Also, static and dynamic external loading is applied to the spindle tool location to confirm the disturbance rejection ability of the closed-loop system.

High-Precision Cutting Tool Tracking With a Magnetic Bearing Spindle

A method is presented for tool tracking in active magnetic bearing (AMB) spindle applications. The method uses control of the AMB air gap to achieve the desired tool position. The reference tracking problem is transformed from the tool coordinates into the AMB control axes by bearing deflection optimization. Therefore, tool tracking can be achieved by an off-the-shelf AMB controller. The method is demonstrated on a high-speed AMB boring spindle with a proportional integral derivative (PID) control. The hypothetical part geometries are traced in the range of 30 μm. Static external loading is applied to the tool to confirm disturbance rejection. Finally, a numerical simulation is performed to verify the ability to control the tool during high-speed machining.

Coupled vibration analysis of Maglev vehicle-guideway while standing still or moving at low speeds

Dynamic instability, that is, resonance, may occur on an electromagnetic suspension-type Maglev that runs over the elevated guideway, particularly at very low speeds, due to the flexibility of the guideway. An analysis of the dynamic interaction between the vehicle and guideway is required at the design stage to investigate such instability, setting slender guideway in design direction for reducing construction costs. In addition, it is essential to design an effective control algorithm to solve the problem of instability. In this article, a more detailed model for the dynamic interaction of vehicle/guideway is proposed. The proposed model incorporates a 3D full vehicle model based on virtual prototyping, flexible guideway by a modal superposition method and levitation electromagnets including feedback controller into an integrated model. By applying the proposed model to an urban Maglev vehicle newly developed for commercial application, an analysis of the instability phenomenon and an investigation of air gap control performance are carried out through a simulation.

2E21 Dynamic analyses and field tests of Incheon urban maglev train-guideway interaction system(Infrastructure)

The maglev train is the strongest candidate for the next-generation railroad system. Among the advantages, lesser vibration and noise due to the non-contact mechanism and the eliminated possibility of derailment are noticeable merits for a high-speed train. It should be noted that the air gap is affected by dynamic behaviors of the maglev train and guideway. Their behaviors also influence to the air gap. Therefore, accurate and precise physical model for the maglev train-guideway interaction system including a control algorithm of the air gap is indispensable for the reliable air-gap control and maglev-train operation, especially for the safe and reliable operation of a maglev train. In the present study, dynamic responses of an urban maglev train-guideway interaction system including a control algorithm are rigorously investigated. The train is represented by a mass-damper-spring system which is levitated electro-magnetically. The guideway is modeled by a three-dimensional frame structure. The electromagnetic forces between the train and guideway are assumed to have small fluctuations from their static values and linearized with respect to the values. In order to control air gaps for levitation, the active control algorithm which was used for the urban transit maglev system in Korea is employed. Dynamic governing equations for the maglev train-guideway interaction system including the control algorithm are derived. Dynamic responses of the system are examined using the governing equations. These analytical results are also verified with the comparison of field measurement tests at Incheon Airport Maglev Railway.