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The composite electromagnetic linear actuator features a co-axial integrated design that merges the moving coil and moving iron actuator types. This design leads to significant interactions among electrical, magnetic, and thermal fields during operation, which in turn affect energy consumption and temperature increases. To further improve the material utilization rate of the actuator and optimize its comprehensive performance, such as force density and temperature rise, a multi-physical field collaborative optimization method was proposed. First, the energy consumption and temperature rise mechanisms of the actuator were analyzed. The bidirectional coupling relationships of multi-physical fields during its operation are studied. Simulations and experiments were conducted to establish the rules governing the spatiotemporal evolution of energy consumption and temperature fluctuations under standard operational conditions. Based on this, a system-level collaborative optimization model for the actuator was established. Sensitivity analysis helped segregate the design variables into system-level and independent categories. Subsequently, using a multi-objective genetic algorithm, the optimal parameter settings were determined. The optimization results revealed that the force constant of the main driving components increased by 5.4%, and the average temperature of the coil decreased by 6.3%; additionally, the starting force of auxiliary components increased by 2.3%, and the temperature of the yoke decreased by 0.8%. [ABSTRACT FROM AUTHOR]

As an important actuator component, the electromagnetic linear actuator has a significant impact on the performance of fully flexible variable valve trains. Aiming at the shortcomings of the conventional moving coil electromagnetic linear actuator (MCELA) with low force density and insufficient end-passive self-holding ability, a novel compound electromagnetic linear actuator (CELA) integrating the advantages of MCELA and the moving iron electromagnetic linear actuator (MIELA) was proposed in this work. The CELA has two operating modes, including single drive mode and cooperative drive mode, and its loss variation is different from that of the single MCELA or MIELA. Firstly, the current and displacement curves under different operating modes were obtained through experiments, which were then used as the excitation source to quantitatively analyze the copper and iron losses under different working conditions by means of 3D finite element simulation. The loss distribution and ratio of CELA under typical operating conditions were discussed in detail. The effects of stroke and valve opening duration on CELA losses were analyzed. The results show that there are significant differences in the loss variation rules between the two operating modes, the losses increase as the working stroke increases in single drive mode. In the cooperative drive mode, the losses are much greater than in the single drive mode, with the losses decreasing in the initial stage and then increasing as the stroke increases. None of the valve opening durations had a significant effect on losses. This study provides a reference for loss studies of other novel electromagnetic linear actuators. [ABSTRACT FROM AUTHOR]

The intelligent control strategy of electromagnetic clutch actuator is analyzed in detail in this paper. The start - stop control of the loom is realized by an electromagnetic clutch. The existing control method of electromagnetic clutch of loom is high and low pressure control strategy. The operator sets the braking advance angle according to experience, to realize the accurate braking of the spindle, but it is difficult to realize the fast and accurate control. In order to achieve good performance, it is very important to develop a fast and accurate loom braking system. Aiming at the fabric defects caused by the elongation of the warp when the loom is stopped, a method of stabilizing the excitation current of the electromagnetic clutch by using the neural adaptive PID (proportional integral differential) controller is proposed to improve the control precision of the actuator. The experimental results show that the proposed control algorithm is feasible and can effectively realize the adaptive control of the spindle braking Angle within the allowable error range. [ABSTRACT FROM AUTHOR]

Electromagnetic linear actuators (ELAs) may be confronted with unsatisfactory performance when subjected to overheating. Therefore, it is significant to clarify its thermal characteristics and design the thermal performance requirements. A thermal analysis method based on multiphysics coupling model was presented, which uses the non-simplified loss distribution as the heat source to calculate the temperature field, adjusts the material properties by temperature, and considers the interaction between motion (including impact) and loss. More importantly, an improved universal equivalent winding to satisfy the condition of real compact concentrated winding was developed. Finally, the validity of this approach was verified through the experiment, and the regularity of temperature was summarized. The results show that the error of simulation and experiment is less than 6% and the permissible continuous operation frequency is no more than 30 Hz. The approach proposed in this paper can be employed not only to the ELA, but also to the design and analysis a wide range of electromagnetic machines. [ABSTRACT FROM AUTHOR]

Thin steel plates are widely used in various industrial products. However, because of the deterioration of surface quality and metal plating that occurs during transport, some problems exist. As a solution to these problems, a noncontact transport of steel plate using electromagnetic force has been proposed. However, side slip or the dropping of the plate may occur. Therefore, we proposed the addition of electromagnetic actuators to control the horizontal motion of levitated steel plates. In this study, we examined the change in the levitation stability during noncontact transport with the addition of positioning control in the horizontal direction or changed transport conditions. As a result, the application of a magnetic field in the horizontal direction improved the levitation stability of transported thin steel plates in different transport conditions. [ABSTRACT FROM AUTHOR]

Magnetic levitation is state-of-the-art technology to realize 6 degree of freedom motion stages. The major weakness of magnetic levitation technology is the small force of the actuators, since electromagnetic actuators usually have small force compared to other actuators. Moreover, they always have to be turned on in order to compensate for the weight of the stage. In this paper, voice coil motors, a kind of electromagnetic actuator, are designed for a magnetic levitation stage. Two different types of voice coil motors are mathematically modeled, analyzed and optimized to obtain high force. According to the optimized final designs, the voice coil motors are manufactured and their performances are evaluated. The optimal design results are compared with the finite element simulations and the test results of the manufactured products. Both types of voice coil motors show high force. The results are quantified and compared. Through the design process and the evaluation of the voice coil motors, a practical design guideline for a voice coil motor is suggested. [ABSTRACT FROM AUTHOR]

Electromagnetic linear actuator (EMLA) is an alternative of the conventional damper in vehicle suspensions and harvests suspensions vibration energy which is wasted generally. Due to large variations of its Back Electromotive Force (Back-EMF), it will thus be interest to investigate how to recycle the electricity efficiently. In this paper, to improve the recycling efficiency of the EMLA, a feedback energy circuit featured with combination of parallel switchover supercapacitors technology and a boost-buck DC-DC converter is proposed on the basis of the generating characteristics of a newly designed EMLA. By modeling the feedback energy circuit, its dynamic characteristics are simulated and its efficiency is investigated. The results of simulations and experiments show that the feedback energy circuit can achieve a wide range of energy recovery regardless of large variations of Back-EMF induced by the EMLA. Simultaneously, by keeping the boost-buck ratio less than 3, the efficiency of energy recovery is high, in some cases could reach 94%. [ABSTRACT FROM AUTHOR]

Aiming at the problems of complex structure and slow response of the existing hydraulic active suspension actuator, an electromagnetic linear actuator (EMLA) with simple structure, stable operation is designed in this paper. Based on completing the structural design of the EMLA, the two-dimensional finite element model is established by using the finite element software JMAG, and transient analysis of EMLA is carried out, including analyses of no-load magnetic field and thrust force characteristics. The prototype is trial-produced, and its thrust force characteristics are measured on a designed test bench. The experimental values are close to the simulated values, which verifies the correctness of the model. Finally, by analyzing the variation of the electromagnetic thrust force under different loading currents, this paper obtains the thrust force constant of the EMLA (183N/A). [ABSTRACT FROM AUTHOR]

In this paper, the design and performance of a multi-degree-of-freedom smart ball-and-socket actuator and its application to rehabilitation training systems are investigated. A key feature of this actuator is the use of magnetorheological fluids which can exhibit dramatic changes in their rheological properties, including yield stress, when subjected to external magnetic fields. These fast and reversible fluid rheological changes permit the smart actuator to provide the required impedance at orthotic arm joints aimed for upper-limb rehabilitation. Electromagnetic finite element analyses using ANSYS software were carried out to design the electromagnetic circuit of the actuator and important design factors affecting the efficiency of the generated magnetic field and its best delivery to the MR fluid, were examined. These factors included the relative permeability of the magnetic material and the electromagnetic coil properties such as its shape, size and location. In addition, the utilisation of non-magnetic materials in the electromagnetic circuit design was investigated with the aim to optimise the performance of the smart actuator. Finally, the performance of the smart actuator was assessed theoretically and numerically under various input conditions in which Bingham plastic fluid characteristics were assumed, and the results determined by the two techniques were found to compare well. [ABSTRACT FROM AUTHOR]

Recently, the majority of artificial hearts have been non-pulsatile types. However natural hearts are pulsatile, and the long-term bio-compatibility of the non-pulsatile types has not been confirmed. We developed a linear actuator that can expect to be applied to pulsatile artificial heart. This linear actuator was applied to an electromagnetic pump. It consists of power transmission, tanks, and permanent magnets. We propose a structure to reduce power consumption by a spring. Reduction in power consumption makes possible to downsize the entire apparatus. [ABSTRACT FROM AUTHOR]

Displacement-amplified electromagnetic actuators (DAEAs) have been developed for efficiently using the electromagnetic attractive force by magnifying the motion of the change of a gap in which the electromagnetic attractive force is generated. This method enables us to use the large electromagnetic force with the gap being small for a larger stroke. This study applies DAEAs to an inchworm mechanism to realize motion on waving rails and precise positioning. A prototype was developed, and a fundamental experiment revealed the performance of the proposed inchworm mechanism. [ABSTRACT FROM AUTHOR]

Ultra-fast circuit breakers are operated with fast electromagnetic actuators. They can generate a sufficient impulse force to swiftly open electrical contacts in a couple of milliseconds. Opening of the contacts with high velocities implies a need for a timely and controllable damping. An efficient damping mechanism then is crucial to attain an appropriate actuation performance and secure a long lifetime. In this paper a finite element model of a Halbach magnet array based magnetic damper and a corresponding experimental prototype is described. A parametric study is performed to understand the effect of load mass and incoming velocities. It was found that the magnetic field modulation plays an important role on the damping performance. A uniform and high radial component of the magnetic flux density is necessary in order to achieve high damping force. The radial magnetic field can be controlled via thickness and magnetization direction of the ring magnets that are used to create the Halbach magnet array. [ABSTRACT FROM AUTHOR]

An electromagnetic acoustic transducer (EMAT) design using an air-cored solenoid coil as a pulsed electromagnet is proposed for the high-temperature non-contact monitoring of metal processing, and the operation of a prototype device is confirmed at temperatures ranging from room temperature to 700 °C. The coil generates a biasing magnetic field that allows the device to overcome the Curie temperature limitations of conventional EMATs. Pulse-echo measurements on carbon steel are made at high temperatures, and the superposition of the nth compression method is used as a signal processing technique to confirm that the shear wave velocity decreases with increasing temperature, and it is verified that the EMAT can operate at high temperature. [ABSTRACT FROM AUTHOR]

The International Space Station (ISS) has been regarding as a laboratory for experiments in numerous microgravity science discipline. However, the microvibration has a serious impact on science experiments on the ISS as well as existing electromagnetic actuators could not satisfy the requirement of good linearity needed for large stroke of low frequency vibration isolation platforms. This paper aims to design a maglev actuator with good linearity, which could be applied to microgravity vibration isolation platforms. Based on the principle of Lorentz force and self-demagnetization effect, the structural form and preliminary design indices of the actuator were presented. In order to minimize the weight and heat consumption of its coil, parametric design was carried out and multi-objective optimization was adopted for it. Moreover, to investigate the dynamic characteristics of the actuator, system identification was performed to obtain a mathematical model of its control channel, which has good fitting degree of the time and frequency domain signals. Therefore, the result provides an important basis for structural optimal design of the actuator for microgravity vibration isolation system. [ABSTRACT FROM AUTHOR]

Authors have proposed an electro/mechanical resonance method to improve characteristics of a linear resonant actuator. However, a reverse current caused by high capacitor voltage was not considered in the finite element analysis. In this paper, we evaluate dynamic characteristics through a modified analysis method in which a reverse current is considered and the validity is confirmed by comparing with measured results. [ABSTRACT FROM AUTHOR]

Moving-iron electromagnetic actuators have been widely used in industry. But the properties are conflict in high levels of linear force, long stroke, low power consumption and high force/volume ratio. A hybrid excited linear actuator (HELA) was proposed to provide an innovative high-performance solution for direct drive valves. The characteristics of static electromagnetic force were optimized and analyzed. Meanwhile, dynamic performance was simulated by 3D finite element method taking into account the eddy current loss of materials. The simulation results agree well with the experiments. And the results show that the prototype's magnetic paths distribution is regulated by the structural parameters, which leads a linear output force within a stroke of ± 3 mm. Besides, the prototype's force/volume ratio is up to 4.5 × 107 N/m3. The holding force at the ends of stroke is more than 120 N. Therefore the holding current is eliminated, which reduces the power consumption effectively. Furthermore, the prototype's time of step voltage response is 4.3 ms and frequency response (-3 dB) of the displacement reaches about 60 Hz. Additionally, the eddy current is a significant factor affecting the dynamic performance, which increases more than 8 percent in the step voltage response time. [ABSTRACT FROM AUTHOR]

Towards at the active radial magnetic bearing with tightly-coupled redundant supporting structure, we propose a kind of fault-tolerant control strategy to make the remaining structures, under the failures of some electromagnetic actuators, reconfigured by compensating the magnetic flux loss to provide expected supporting force continually. By using FSS (fault status series) to describe the fault status of actuators, an index rule of the current distribution scheme has been designed to resolve different failure conditions of actuators. Fault-tolerant control model has been established to verify the electromagnetic force generation in tightly-coupled redundant supporting structures after failure of actuators. The influence characteristic and mechanism of the bias current coefficient to electromagnetic force generation have been analyzed. The application example shows that fault-tolerant control strategy discussed can restrain the influence of the disturbing force to stabilize the rotor even under the failures of some actuators. In addition, inappropriate selection of the bias current coefficient will be easy to cause electromagnetic force limited by saturation constraint, and unable to provide the desired supporting force, which leads to rotor drop. Improving the real-time performance will effectively reduce the rotor jitter in the reconfiguration of redundant structure discussed. [ABSTRACT FROM AUTHOR]

This paper presents a helical teethed linear actuator (HTLA) for artificial muscles of human coexistence robots. The HTLA has small number of simple-shaped permanent magnets and coils. The advantages of this actuator are a high force constant and capability of accurate assembly. The performances of the HTLA were investigated by using 3-D finite element method (FEM). As a result, it was found that the maximum thrust force was 23.1 N, and the efficacy of the PID position control for the HTLA was confirmed. In addition, by the force control using encoder signals, the detent force was decreased to 0.56 N and the force constant was 34.9 N/A. Moreover, the control of the stiffness for flexible motions was implemented by using compliance control. [ABSTRACT FROM AUTHOR]

This paper presents the design concept of a magnetically levitated linear slider with non-contact energy transfer, and an analysis of the major components of the design. An open-end generator is introduced to achieve non-contact energy transfer to the levitated platform. Utilization of non-contact energy transfer will overcome difficulties related to charging batteries. Furthermore, we have proposed an improvement for a hybrid electromagnet to achieve better passive lateral alignment under zero power control. The results of FEM analysis and practical testing show that the concept is promising for further study with a prototype system. [ABSTRACT FROM AUTHOR]

This paper presents a novel direct-drive linear compressor for air brake system in electric vehicles. By integrating the free piston and mechanical springs into a moving-coil type electromagnetic linear oscillating actuator (EMLOA), the structure of the proposed linear compressor is increasing compact. Moreover, the novel features, such as high thrust force constant, better controllability, and high resonant frequency, enable the linear compressor to operate most efficiently at resonance. The thrust force constant is enhanced by employing quasi-Halbach array and is tested to be high (74 N/A) and unchanged over the whole stroke. Dynamic modeling and experiment validation are performed to analyze dynamic characteristics of the linear compressor. The experimental and simulated data agree well, by regulating the frequency and amplitude of the excitation current, the high efficiency of the EMLOA (91.7%) and the low energy volume ratio of the linear compressor (7.3 kW/(m3/min)) indicate that the proposed linear compressor is significant energy saving compared with conventional compressors. [ABSTRACT FROM AUTHOR]

A compact electro-magnetic oscillatory actuator was proposed based on a pair of torsion springs for optical scanners operating at low oscillating frequencies, such as 50 Hz for a portable barcode scanner. Each torsion spring in the actuator is made of silicone rubber and is dually supported at both ends. A yoke is coupled with the driven coil to enhance the driving torque of the actuator. In this study, we analyzed the effect of the yoke on the resonant frequency of the actuator, as well as the torsion moment. We also experimentally determined the relationship between the resonant frequency and the magnetic gap of the yoke. Compared with the mechanical resonant frequency in the experiments, which was designed to be 50 Hz, the frequency was modified to 57.4 Hz, 54.7 Hz and 52.9 Hz when the gap between the yoke and the permanent magnet was 1.5 mm, 1.7 mm and 1.9 mm, respectively. The proposed actuator, which combines a yoke with flexible torsion springs, is potentially useful as a compact optical scanner, taking advantages of both low power consumption and high reliability. [ABSTRACT FROM AUTHOR]

This paper presents the research on loss analysis of the electromagnetic linear actuator (ELA) with the purpose of performance improvement of ELA applied to the engine electromagnetic driven valve train (EDVT). To define ELA's loss distribution and variation, quantitative analysis has been carried out against ELA's loss composition and variation at different engine conditions through simulation of three-dimensional (3D) finite element. Meanwhile, in order to verify reliability of simulation model, locked-mover test has been completed creatively. Then it analyzes the impact of flux density and excitation period on ELA's loss and thus some regular understandings are obtained. In the end, the result shows that the test data and simulating calculation agree well, and the error is less than 3.9%. [ABSTRACT FROM AUTHOR]

Skeletal muscle exhibiting complex and excellent precision has evolved for millions of years. Skeletal muscle has better performance and simpler structure compared with existing driving modes. Artificial muscle may be designed by analyzing and imitating properties and structure of skeletal muscle based on bionics, which has been focused on by bionic researchers, and a structure mode of linear electromagnetic array artificial muscle has been designed in this paper. Half sarcomere is the minimum unit of artificial muscle and electromagnetic model has been built. The structural parameters of artificial half sarcomere actuator were optimized to achieve better movement performance. Experimental results show that artificial half sarcomere actuator possesses great motion performance such as high response speed, great acceleration, small weight and size, robustness, etc., which presents a promising application prospect of artificial half sarcomere actuator. [ABSTRACT FROM AUTHOR]

Skeletal muscle exhibiting complex and excellent precision has evolved for millions of years. Skeletal muscle has better performance and simpler structure compared with existing driving modes. Artificial muscle may be designed by analyzing and imitating properties and structure of skeletal muscle based on bionics, which has been focused on by bionic researchers, and a structure mode of linear electromagnetic array artificial muscle has been designed in this paper. Half sarcomere is the minimum unit of artificial muscle and electromagnetic model has been built. The structural parameters of artificial half sarcomere actuator were optimized to achieve better movement performance. Experimental results show that artificial half sarcomere actuator possesses great motion performance such as high response speed, great acceleration, small weight and size, robustness, etc., which presents a promising application prospect of artificial half sarcomere actuator. [ABSTRACT FROM AUTHOR]

The paper describes a newly developed miniature moving-magnet type linear actuator with proportional action that uses repulsive magnetic forces. Out of four possible structures, two with mobile magnets and two with fixed ones, the most simple and cheap prototype was chosen, offering good possibilities to obtain a miniature structure. A comparative numerical analysis for two types of mobile element justifies the adopted constructive solution. A laboratory prototype was analyzed numerically and experimentally in view of a possible optimization, the experimental and numerical results being in good agreement. Finally a prototype actuator was built and tested. [ABSTRACT FROM AUTHOR]