• Title/Summary/Keyword: Linear force motor

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Development of an Ultra Precision Hydrostatic Guideway Driven by a Coreless Linear Motor

  • Park Chun Hong;Oh Yoon Jin;Hwang Joo Ho;Lee Deug Woo
    • International Journal of Precision Engineering and Manufacturing
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    • v.6 no.2
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    • pp.55-60
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    • 2005
  • In order to develop the hydrostatic guideways driven by a core less linear motor for ultra precision machine tools, a prototype of guideway is designed and tested. A coreless linear DC motor with a continuous force of 156 N and a laser scale with a resolution of 0.01 ㎛ are used in the system. Experimental analysis on the static stiffness, motion errors, positioning error and its repeatability, micro step response and velocity variation of the guideway are performed. The guideway shows infinite stiffness within 50 N applied load in the feed direction, and by the motion error compensation method using the Active Controlled Capillary, 0.08 ㎛ linear motion error and 0.1 arcsec angular motion error are acquired. The guideway also reveals 0.21 ㎛ positioning error and 0.09 ㎛ repeatability, and it shows stable responses following a 0.01 ㎛ resolution step command. The velocity variation of feeding system is less than 0.6 %. From these results, it is estimated that the hydrostatic guideway driven by a coreless linear motor is very useful for the ultra precision machine tools.

Development of a Hydrostatic Guideway Driven by the Linear Motor (리니어모터를 이용한 초정밀 유정압안내면 개발)

  • 박천홍;오윤진;황주호;이득우
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.6
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    • pp.139-144
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    • 2004
  • In order to discuss the availability of hydrostatic guideways driven by the coreless linear motor to ultra precision machine tools, a prototype of guideway is designed and tested in this research. A coreless linear DC motor with the continuous force of 156 N and a laser scale with the resolution of 0.01 ${\mu}{\textrm}{m}$ are used as the feeding system. The experiments are performed on the static stuffiness, motion accuracy, positioning accuracy, microstep response and variation of velocity. The guideway has the infinite axial stillness within 50 N of applied load, and by the motion error compensation method using the Active Controlled Capillary, 0.08 ${\mu}{\textrm}{m}$ of linear motion error and 0.1 arcsec of angular motion error are acquired. The guideway also has 0.21 ${\mu}{\textrm}{m}$ of positioning error and 0.09 ${\mu}{\textrm}{m}$ of repeatability, and it shows the stable response against the 0.01 ${\mu}{\textrm}{m}$ resolution step command. The velocity variation of feeding system is less than 0.6 %. From these results, it is confirmed that the hydrostatic guideway driven by the coreless linear motor is very useful fur the ultra precision machine tools.

An ENG analysis for estimating the individual capabilities of the rectus femoris muscle (EMG 분석을 이용한 대퇴직근의 근력추정)

  • Lee, Myeon-U;Lee, Gu-Hyeong
    • Journal of Korean Institute of Industrial Engineers
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    • v.7 no.2
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    • pp.3-17
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    • 1981
  • Isometric muscle strength has become important as it is realized that a large variation in the human exists and is affected by many personal and environmental factors. Experiments have been performed for estimating the individual capabilities of the quadriceps femoris muscle in man. The surface EMG has been recorded on the belly of the rectus femoris muscle during voluntary isometric continuous exertion at 25%, 50%, 75%, and 100% MVC. As a muscle force (% MVC) increases, the rectified mean EMG amplitude increases in a non-linear form. The rectified mean EMG amplitude also increases in a non-linear with respect to fatigue progression. As the muscle force (% MVC) increases, an endurance time of isometric exertion decreases linearly. Analysis shows that rectified mean EMG amplitude is a consistent and sensitive measure of motor unit recruitments and can be useful in estimating an individual capability of a local muscle. Further, the result satisfies the sufficient condition that type S motor units are recruited first, while large motor units are recruited progressively as the fatigue develops.

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Characteristic Analysis of Permanent Magnet Linear Synchronous Motor with Halbach Array and Iron Core (영구 자석 Halbach 배열 가동자로 구성된 철심형 직선 영구자석 동기 전동기의 특성 해석)

  • Jang, Seok-Myeong;You, Dae-Joon;Lee, Sung-Ho;Jang, Won-Bum;Kwon, Jeong-Ki
    • Proceedings of the KIEE Conference
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    • 2003.10b
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    • pp.72-74
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    • 2003
  • This paper presents a design and analysis solutions for the general class of iron-cored permanent magnet linear synchronous motor with Halbach (PMLSM). In our design and analysis, rotor consisting of permanent magnets rotor and slot less iron-cored coil stator are treated in a uniform way via vector potential. For one such motor structure, we give analytical formulas for its magnetic field, back electromotive force, inductance of winding coil, and trust force. We also provide performance comparisons of three types according to iron-cored and PM array.

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Simulation of the Reduction of Force Ripples of the Permanent Magnet Linear Synchronous Motor

  • Chung, Koon-Seok;Zhu, Yu-Wu;Lee, In-Jae;Lee, Kwon-Soon;Cho, Yun-Hyun
    • Journal of Electrical Engineering and Technology
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    • v.2 no.2
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    • pp.208-215
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    • 2007
  • The significant drawback of the permanent magnet linear synchronous motor (PMLSM) is force ripples, which are generated by the distortion of the stator flux linkage distributions, cogging forces caused by the interaction of the permanent magnet and the iron core and the end effects. This will deteriorate the performance of the drive system in high precision applications. The PMLSM and its parasitic effects are analyzed and modeled using the complex state-variable approach. To minimize the force ripple and realize the high precision control, the components of force ripples are extracted first and then compensated by injecting the instantaneous current to counteract the force ripples. And this method of the PMLSM system is realized by the field oriented control method. In order to verify the validity of this proposed method, the system simulations are carried out and the results are analyzed. The effectiveness of the proposed force ripples reduction method can be seen according to the comparison between the compensation and non-compensation cases.

The Shape Optimization of PM Excited Transverse Flux Linear Motor for Compressor to Minimize Detent Force and Maximize Thrust force (Detent force를 최소화 하면서 추력을 최대화하기 위한 압축기용 영구자석 여자 횡자속 선형전동기의 형상최적설계)

  • Hong, D.K.;Woo, B.C.;Kang, D.H.;Jang, J.W.;Kim, J.M.;Jeong, D.H.
    • Proceedings of the KIEE Conference
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    • 2005.10c
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    • pp.147-149
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    • 2005
  • On this study, we optimized maximizing thrust force of weight ratio and minimizing detent force of weight ratio at the TFLM(Transverse Flux Linear Motor) using design of experiments by the table of orthogonal array, characteristic function and analysis of means(ANOM), For two functions or more, the effectiveness of design change can be evaluated in accordance with change in design parameters. Also, The stator and mover weight of TFLM is reduced by up to 20 percent while its thrust force of weight ratio and detent force of weight improved. From now on, we are going to apply the required technique to design various uses and shares of the TFLM.

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A Study on the reduction of cogging force of stationary discontinuous armature Permanent Magnet Linear Synchronous Motor by change in Auxiliary pole (보조극 변화에 따른 전기자 분산배치 영구자석형 리니어 동기 모터의 코깅력 저감에 관한 연구)

  • Lee, Kyu-Myung;Kim, Yong-Jae
    • The Journal of the Korea institute of electronic communication sciences
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    • v.5 no.6
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    • pp.613-619
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    • 2010
  • The stationary discontinuous armatures that are used in permanent magnet linear synchronous motors (PM-LSMs) have been proposed as a driving source for transportation systems. However, the stationary discontinuous armature PM-LSM contains the outlet edges which always exist as a result of the discontinuous arrangement of the armature. For this reason, the outlet edge cogging force generated between the armature's core and the mover's permanent magnet. This paper contemplated the outlet cogging for ceaccording to 2-D numerical analysis by FEM. We installed the auxiliary pole for in order to minimize the outlet cogging force.

Design of a Linear Ultrasonic Actuator for Small Lens Actuation (초소형 렌즈 구동을 위한 선형 초음파 구동기 설계)

  • Kwon, Tae-Seong;Choi, Yo-Han;Lee, Seung-Yop
    • Transactions of the Society of Information Storage Systems
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    • v.2 no.4
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    • pp.251-256
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    • 2006
  • There is a great demand of micro-actuators for mobile information devices such as SFF optical drives and mobile phone cameras. However, the magnetic coils used in conventional electromagnetic motors are a major obstacle for the miniaturization because of their complicated structures and large power consumption. In this paper, a linear ultrasonic motor to actuate focusing lens of mobile devices is proposed. The new actuator uses a ring type bimorph piezoelectric material, and $d_{31}$ mode is adopted for applying linear motion. The interaction between inertia force and friction force makes linear motion by high-frequency saw signal input. The saw signal gives steady forces on the one direction by asymmetric inclination property of the signal itself on time domain. A commercial FEM(ANSYS) was used in this investigation for simulating structural analysis, identification of dynamic property, such as resultant displacement and coupled analysis with piezoelectric material. To evaluate the performance of the new design, a prototype was manufactured and experiments were carried out. Experimental results show the actuator motion of 5.4 mm/s at 10V saw signal of 41 kHz.

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Force Characteristic Analysis of Linear Switched Reluctance Motor according to Design Parameter (설계 변수에 따른 리니어 스위치드 릴럭턴스 전동기의 힘특성 해석)

  • Jang, Seok-Myeong;Park, Ji-Hoon;Choi, Jang-Young;You, Dae-Joon;Ko, Kyoung-Jin;Sung, Ho-Kyung
    • Proceedings of the KIEE Conference
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    • 2008.04c
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    • pp.77-79
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    • 2008
  • This paper deals with extraction of design parameters of Linear Switched Reluctance Motor (LSRM) based on force calculation using space harmonic analysis, 2D Finite Element Method (FEM) and experimental measurement. First, analytical solutions for flux density due to mover winding currents are derived in terms of magnetic vector potential and a 2D rectangular coordinate system, for the case when the mover is located at aligned and unaligned position. The analytical results are compared with those obtained from a 2D FEM Second, using Fourier series expansion, this paper predicts the force profile of LSRM analytically.

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