Electromagnetic Linear Actuator Research Articles

Design and analysis of an electromagnetic linear actuator for SUV active suspension

Design and analysis of an electromagnetic linear actuator for SUV active suspension

Design and Manufacture of a Linear Actuator Based on Magnetic Screw Transmission

This article proposes a practical design guide for a linear electromagnetic actuator based on the concept of magnetic screw transmission, in which manufacturing and assembly technologies are investigated. The surface-inserted design is first used to form a required helical-shape magnetic pole, which exhibits simple processing, high precision, and robust structure. Moreover, different topologies are developed using the 3-D finite-element analysis aided design, with the goal of optimizing thrust force. In addition, different number of permanent-magnet (PM) segments are first proposed to reduce the cogging effect. Afterward, the linear actuator integrates the rotary machine and the magnetic screw together to construct a compact design and decouples the magnetic circuits. The decoupling design focuses on the self-shielding effect of the Halbach PM array, and the special bearing supports are selected to avoid the eccentricity. Finally, a prototype is built using the developed techniques. Experiments are carried out on a linear test bench, verifying the theoretical analysis.

Optimal Trajectory Planning of Electromagnetic Valve-Train Based on Multiple Algorithms for Improving Engine Performance

Electromagnetic valve-train (EMVT) is a camless variable valve technology that can adjust the valve movement state independently, continuously and in real time. It can adjust the engine charge efficiency according to engine working conditions. In this paper, in order to achieve the optimal inflation efficiency, a new-style moving-coil electromagnetic linear actuator (ELA) was designed and genetic algorithm (GA) was used to plan the valve motion trajectory in common working conditions. Furthermore, an improved BP neural network algorithm was used to optimize the valve operation mode in all working conditions. The new valve operation scheme was applied to the modified intake system of engine, and its simulation and test analysis were carried out. Compared with the prototype, the results showed that the charging efficiency was greatly improved in the range of full rotating speed, especially in the range of middle and low rotating speed up to 95.6%.

Variable Weight Coefficient Optimization of Gearshift Actuator With Direct-Driving Automated Transmission

Direct-Driving Automated Mechanical Transmission (DAMT) gearshift actuator is a kind of electromagnetic linear actuator. In practical application, the actual gearshift force in each steady states is significantly different from the electromagnetic force model. For the optimization of gear shifting actuator with undetermined volume constraint, this paper presents a variable weight coefficient optimization method of electromagnetic linear actuator which equates the output forces under different steady states in the fitness function. These are intended to adjust the relationships among the optimized objects by using the fitness function to improve the overall optimization effect. In order to obtain the fitness value of each combination parameter accurately, finite element analysis (FEA) is adopted in this paper, to improve the efficiency of the algorithm, and a more efficient simulated annealing -particle swarm optimization algorithm (SA-PSO) is used by the proposed optimization method. Finally, experiment is carried out based on prototype of gearshift actuator to verify the optimization results. The results show that the maximum electromagnetic force and terminal electromagnetic force are both increased by more than 20%, and the volatility of gearshift force is reduced 26.4%, which ensures the structure compactness and fast response. The proposed method decreases the volatility by 27.5% compared with the constant weight coefficients and improves the gearshift force in each stage.

Optimal Design and Experimental Research on a New Hybrid Electromagnetic Actuator for Vehicles

In this study, a new hybrid electromagnetic actuator (HEMA) that integrates a cylindrical permanent magnet linear synchronous motor and a hydraulic damper is proposed and designed to solve the problem of poor reliability of a linear electromagnetic actuator. A modified skyhook control that matches the structure of the HEMA is adopted, and the performance parameters are optimized. Then, the relationships among structural parameters of the HEMA are analyzed using equivalent magnetic circuit method. On the basis of these relationships, multiple alternative groups of structural parameters are obtained. Moreover, finite element models are established in Ansoft Maxwell software. The structural parameters of the HEMA are optimized and determined to produce the peak electromagnetic thrust force that the linear motor requires. Finally, a prototype is developed on the basis of the optimized results for the bench test. Test results show that the linear motor tracks the desired force effectively. In contrast to the passive damper, the body acceleration and suspension working space of HEMA are decreased by 20.6% and 13.3%, respectively. The dynamic tire load is increased by 16%, which is in a reasonable range. And compared with LEMA, the body acceleration is increased by 2.73%, but the suspension working space and dynamic tire load are reduced by 1.1% and 38.1%. All the results above mentioned demonstrate that the HEMA can considerably improve the vehicle dynamic performance.

Design of an Electromagnetic Variable Valve Train with a Magnetorheological Buffer

In this paper, an electromagnetic variable valve train with a magnetorheological buffer (EMVT with MR buffer) is proposed. This system is mainly composed of an electromagnetic linear actuator (EMLA) and a magnetorheological buffer (MR buffer). The valves of an internal combustion engine are driven by the EMLA directly to open and close, which can adjust the valve lift and phase angle of the engine. At the same time, MR buffer can reduce the seat velocity of the valve and realize the seat buffer of the electromagnetic variable valve. In this paper, the overall design scheme of the system is proposed and the structure design, finite element simulation of the EMLA, and the MR buffer are carried out. The electromagnetic force characteristics of the EMLA and buffer force of the MR buffer are measured, and the seat buffering performance is verified as well. Experiments and simulation results show that the electromagnetic force of the EMLA can reach 320.3 N when the maximum coil current is 40 A. When the current of the buffer coil is 2.5 A and the piston’s motion frequency is 5 Hz, the buffering force can reach 35 N. At the same time, a soft landing can be realized when the valve is seated.

Modeling and Analysis of an Electromagnetic Fully Variable Valve Train with a Magnetorheological Buffer

Electromagnetic fully variable valve train (EMVT) technology promises to improve the fuel economy and optimize the engine performance. A novel EMVT equipped with a magnetorheological buffer (EMVT with MR buffer) is proposed to suppress the valve seating impact in this paper. The magnetorheological buffer can adjust the damping characteristics of the whole system in the seating process. Valve precise motion control and better seating performance can be achieved through the coordinated control of electromagnetic linear actuator (EMLA) and MR buffer. For better analysis of system performance, establishing an accurate system dynamic model is the basis of the coordinated control system. A high-order nonlinear precise model integrating dynamics, electromagnetism, and fluid mechanic was established. Then, the Jacobi linearization model is carried out at the equilibrium seating point to build a control-oriented linearized model. The correctness and accuracy of the linearized model is verified. Experiments and simulations show that the valve precise motion can be well controlled to achieve fully variable actuation. And the valve soft landing can be completed under collaborative control.

Shift Force Optimization and Trajectory Tracking Control for a Novel Gearshift System Equipped With Electromagnetic Linear Actuators

Electromagnetic linear actuators (ELAs) are used to engage gears in an electric automated manual transmission. The structure is simplified due to the elimination of intermediate mechanisms. An ELA can provide 1500 N of electromagnetic force to drive the synchronizer mechanisms. Additionally, the dynamic characteristics of the actuator are remarkable, improving the performance of shifting gears. To achieve balanceable and comprehensive gearshift performance including shift time, friction work, and degrees of jerk, Pontryagin's minimum principle is employed to optimize the friction torque, and current feed-forward active disturbance rejection control is proposed to track the optimized shift force. Moreover, a double closed-loop controller based on active disturbance rejection control is used to achieve fast and stable displacement control. Comparative simulations and experiments are carried out, and the results indicate that the proposed tracking method can implement the optimal shift force well and can integrate the optimal shift indices, including shift time, degrees of jerk, and friction work. Combined with the proposed control method, the superiority and feasibility of the novel direct-drive electromagnetic gearshift system are validated.

A Magnetic and Mechanical Force Model for the Design of an Archimedean Spiral Flexure Bearing for a Linear Direct-Drive Electromagnetic Actuator

This paper deals with the presentation of a theoretical model developed to help the design of a suspension guiding element of a linear direct-drive magnetic actuator using Archimedean spiral flexure bearings. While most of current approaches only focus on the linear force of this actuator, this paper aims to emphasis the radial force evolution with off-centering of the moving part, eventually allowing a precise dimensioning of the guiding element. The first part of the paper is dedicated to the theoretical calculation of both the magnetic axial force and the magnetic radial force acting between the magnetized moving part and the stator part of the actuator. This calculation is led with a three-dimensional (3-D) to 2-D magnetic permeance network. In the second part of the paper, another theoretical model is led to calculate both the axial and radial mechanical behavior of the flexure bearings also used as springs. The stiffness of the spring is calculated taking into account its parameters versatility, namely in terms of geometry variation and relative to the number of spiral arms. A comparison between the models, the finite element method and the measurements on a prototype are also proposed to validate both models that eventually give acceptable results. The combination of both models—the magnetic one and the mechanical one—enables a fast and accurate evaluation of the viability of the actuator design for the engineer.

Multiphysics methodology for thermal modelling and quantitative analysis of electromagnetic linear actuator

Multiphysics methodology is a preferred tool for the design and optimization of electromagnetic linear actuators (EMLA). In this paper, a multiphysics method was proposed, which uses the non-simplified energy consumption distribution as the heat source for temperature field calculation, adjusts the material properties by temperature, and considers the interaction between motion (including impact) and loss. Then comprehensive experiments and quantitative analysis were carried out. The results show that the errors between simulated and experimental results of indices such as landing velocity, input circulating energy, iron loss and temperature rise of prototype were less than 5%. The prototype’s total iron loss was decreased by 57.6% with fixed armature and dynamic response time was decreased by 10.4% without eddy current compared with the normal condition. This result validated the precision and necessity of the coupling model. In addition to being applied to EMLA, the proposed methodology can be used for analysis and design of a wide range of electromagnetic actuators.

Adaptation of the penalty function method to genetic algorithm in electromagnetic devices designing

PurposeThe purpose of this paper is to elaborate the effective method of adaptation of the external penalty function to the genetic algorithm.Design/methodology/approachIn the case of solving the optimization tasks with constraints using the external penalty function, the penalty term has a larger value than the primary objective function. The sigmoidal transformation is introduced to solve this problem. A new method of determining the value of the penalty coefficient in subsequent iterations associated with the changing penalty has been proposed. The proposed approach has been applied to the optimization of an electromagnetic linear actuator, and the mathematical model of the devices contains equations of the magnetic field, by taking into account the nonlinearity of ferromagnetic material.FindingsThe proposed new approach of the penalty function method consists in the reduction of the external penalty function in successive penalty iterations instead of its increase as it is in the classical method. In addition, the method of normalization of constraints during the formulation of optimization problem has a significant impact on the obtained results of optimization calculations.Originality/valueThe proposed approach can be applied to solve constrained optimization tasks in designing of electromagnetic devices.

Gearshift performance improvement for an electromagnetic gearshift system based on optimized active disturbance rejection control method

Electric automated manual transmission usually adopts direct current motors and intermediate gearings to accomplish gear change. The structure can be simplified further to achieve better dynamic response and mechanical efficiency. A new type of gearshift system which adopts two electromagnetic linear actuators is presented. The intermediate gearings including motion converters are canceled, and the electromagnetic linear actuators drive the shift fork directly to move the synchronizer to engage different gears. The novel gearshift system is described in detail, including the connection, working principle, and performance. Specific working phases of the synchronization are introduced and mathematical equations of each phase are provided. After the specific feature analysis of each phase, the performance effect factors are deduced and the corresponding control requirements are proposed. Considering the stability of the performance, the robust control method, namely, active disturbance rejection control, is adopted. The time optimal method is introduced to optimize the dynamic response of the active disturbance rejection control method to achieve a shorter gearshift time. Comparative simulations among the active disturbance rejection control, time optimal–active disturbance rejection control, and proportional–integral–derivative methods show the distinct improvements of the novel gearshift system combined with the time optimal–active disturbance rejection control method. Finally, gearshift experiments are implemented. The results demonstrated the availability of the novel gearshift system and the designed control strategy.

Inhibition of iron loss of the inner yoke in electromagnetic linear actuator

The iron loss of inner yoke accounts for the majority of iron loss of an electromagnetic linear actuator (ELA). Therefore, the reduction of iron loss of inner yoke is of great importance to the reduction of iron loss of the whole ELA. This study investigates the formation mechanism and distribution law of ELA iron loss and proposes a reduction scheme by arranging groove structures in the inner yoke. The direction of groove arranged in inner yoke was determined based on the formation mechanism of inner yoke iron loss. Through simulation and calculation based on finite-element model of electromagnetic field, the authors investigated the effects of the number of grooves as well as groove width on the iron loss and performance of ELA. The optimal grooving scheme of ELA was determined by comprehensive analysis and analytic hierarchy process. Finally, block and static force tests were carried out based on ELA prototype. It was found that the simulation results were consistent with test results, indicating the accuracy of the simulation model.

The Research on the Motion State Monitoring of Electromagnetic Valve Train of Engine Based on Internet of Things

Aiming at real-time monitoring of valve motion online in a new engine valve train that replaces the traditional cam with a self-developed new electromagnetic linear actuator, this paper presents a system scheme for motion monitoring of the electromagnetic linear actuators based on the Internet of Things and support vector machine (SVM) algorithm, which can effectively monitor the running state of the electromagnetic linear actuator and the valve. The system uses the lower computer to collect the current of electromagnetic linear actuator, and real-time transmits the data to the upper computer in the monitoring center. The upper computer firstly extracts the eigenvector of the motion state of the actuator by wavelet packet decomposition method, and then uses the artificial bee colony algorithm (ABC) to optimize the model kernel function parameters and penalty factor C of support vector machine, and establishes ABC-SVM electromagnetic linear actuator's motion state model and training. In this paper, the method is compared with the direct-collected wire-controlled detection method. The results show that the system can accurately and quickly monitor and analyze the electromagnetic linear actuator and engine valve operating state, so it is feasible.

Fault Monitoring and Diagnosis of Actuators in Electromagnetic Valve-Train Based on Neural Networks Optimization Algorithm

In order to realize fully flexible variable valve lift and improve the intake efficiency of the engine, a new electromagnetic valve-train (EMVT) was designed to replace the traditional CAM in the engine valve-train. However, as the durability of electromagnetic linear actuator (ELA) in the EMVT was lower than that of CAM, and there might be some problems during a long running time. This paper presented an improved online fault diagnosis method combining BP Neural Networks with Grey Relation Analysis (GRA) to analyze current signals, which could realize the monitoring, diagnosis of electromagnetic linear actuator faults and early warning so as to prevent unnecessary situations such as accidental cylinder stop of the engine. The results showed that this method had a high fault diagnosis rate, high speed, reliability and practicability.

A Piezoelectric and Electromagnetic Dual Mechanism Multimodal Linear Actuator for Generating Macro- and Nanomotion.

Fast actuation with nanoprecision over a large range has been a challenge in advanced intelligent manufacturing like lithography mask aligner. Traditional stacked stage method works effectively only in a local, limited range, and vibration coupling is also challenging. Here, we design a dual mechanism multimodal linear actuator (DMMLA) consisted of piezoelectric and electromagnetic costator and coslider for producing macro-, micro-, and nanomotion, respectively. A DMMLA prototype is fabricated, and each working mode is validated separately, confirming its fast motion (0~50 mm/s) in macromotion mode, micromotion (0~135 μm/s) and nanomotion (minimum step: 0~2 nm) in piezoelectric step and servomotion modes. The proposed dual mechanism design and multimodal motion method pave the way for next generation high-precision actuator development.

Design and Performance Evaluation of Modular Compliant Mechanisms

In this study, modular design for compliant stage using a parallelogram flexure module is proposed. The material of the proposed stages chosen is Aluminium alloy T6-6051 due to excellent phase stability, low internal stresses, low density etc. The stage is driven by a linear electromagnetic actuator i.e. voice coil actuator. The preliminary static structural analysis is used to determine the range of motion, stiffness by considering stress limitations. FEA results show a maximum range of motion up to 30mm without exceeding stress limit of 275 Mpa. The proposed mechanisms provide low stiffness in the degree of freedom directions and provide large stiffness in the degree of constraint direction.so it is adequately constrained. The stage provides high precision and repeatability with an increased range of motion, minimal parasitic motions (i.e.150 microns) and limited cross axes coupling.

Model-Free Adaptive Control of Direct Drive Servo Valve of Electromagnetic Linear Actuator

An electromagnetic linear actuator (EMLA) has a promising application in direct motion control. However, ELMA will inevitably inherit uncertainties in the face of load changes, system parameter perturbation, and inherent system nonlinearities, all of which constitute disturbances adversely affecting the precision and adaptability of the control system. A model-free adaptive control (MFAC) strategy based on full form dynamic linearization (FFDL) was proposed to reduce the sensitivity of the control system to the disturbances. An adaptive control of direct drive servo valve was achieved based on the online interaction of characteristic parameters and control algorithms. The feasibility and precision of the proposed algorithm were verified through simulation and experimental results. The results show that the proposed algorithm could achieve adaptive adjustment of the servo valve response at different openings of 0-3 mm without changing control parameters, with the response time controlled within 10ms and steady state error less than 0.04mm. Furthermore, the proposed algorithm had better robustness and capacity of resisting disturbance.

Tree replanter: a solar powered approach

Tree Transplantation is referred to as the procedure of unearthing the trees and replanting them from one location to another with the objective of re-growing the tree to a new location. This involves moving the tree with the root ball-system thereby protecting while tak-ing up the wider roots. In the proposed design, we use electromagnetic linear actuators working with solar energy instead of hydraulic or pneumatic actuators which consume fossil fuels. Here, a three-blade system is used to unearth the tree wherein the rare blades are opened to encircle the tree and the blades are positioned around the tree to ensure that the root ball is at an equal distance from all sides of the trunk. The blades are closed to remove the tree with the root ball intact. The tree with the spade is adjusted to the truck for safe transport.

Design and analysis of a bi-stable linear force actuator for directly-driven metering pump

As a kind of energy converter, high quality electromagnetic linear actuator is the focus of the research. A new flow regulation method for metering pump is proposed, a novel bi-stable linear force actuator (BLFA) is investigated corresponding to reduce power consumption and enhance drive capability. A coupling model including a loss model, an electromagnetic model and a mechanical model was constructed. The influence rule of the structural parameters on force characteristic was investigated. Through structural parameter design, force versus position characteristic is high-linearity in working area and the minimum threshold value of drive force (start-up force) reaches 139 N without spring mechanism, which effectively reduces the device’s volume. Besides, power consumption in holding phase is decreased because of holding force. Moreover, an innovative pulse current excitation mode was adopted to reduce power consumption further. Experimental and simulation results validate the static and dynamic performance of BLFA. The circulating power consumption of prototype is 3.1 J, which does not change with the working frequency and has decreased by 34% compared with the traditional excitation mode. Additionally, the advantage of BLFA’s performance was also verified with directly-driven metering pump flow characteristic experiment.