• Title/Summary/Keyword: Linear motors

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A study on the optimal control of Long Stroke Fast Tool Servo Systems (장거리 구동용 FTS 의 최적 제어에 관한 연구)

  • 이상호;이찬홍;김갑순
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.818-821
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    • 2004
  • With a rapid development in the area of micro and ultra precision technology, the micro surface machining of small size parts are explosively increased. Especially, to improve efficiency of various beams in lens and reflector, non-rotational symmetric form and several mm level heights changeable surface can be machined at a time. These geometric complex 3D surface cannot be machined by general short stroke FTS. The long stroke FTS if firmly needed to move directly several mm and have nm level positioning accuracy for the complex surface form. The long stroke FTS used linear motors to drive moving unit long and fine, aero static bearings to decrease friction and moving errors in guide way, optical linear scale with nm level resolution to measure position of FTS. Furthermore, to increase the performance of acceleration of FTS, the light material, such as AL is used for the structure and the high stiffness box type structure is selected. In this paper, the genetic algorithm approach is described to determine a set of design parameters for auto tuning. The authors have attempted to model the design problem with the objective of minimizing the error, such as variable pattern change. This method can give the better alternative than existing other method.

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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.

Performance Assessment and Contouring Error Prediction of High Speed HMC (고속 HMC 이송계의 운동특성 평가 및 운동오차 예측)

  • 최헌종;허남환;강은구;이석우;홍원표
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.375-381
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    • 2004
  • Recently, the evolution in production techniques (e.g. high-speed milling) and the complex shapes involved in modem production design has been increasingly popular. The key to the achievement is a drastic improvement of the dynamic behavior of the machine tool axes used in production machinery. The more complex these tool paths the higher the speed and acceleration requirements. But it is very difficult to reach the target for high speed machine tool because of the limitations of servo system and motion control system. However the direct drive design of machine tool axes, which is based on linear motors and which recently appeared on the market, is a viable candidate to meet the ever increasing demands, because of these advantages such as no backlash, less friction, more mechanical simplicity and very higher acceleration and velocity comparing to the traditional system. This paper focused on the performance tests of the high speed horizontal machine tool based on linear motor. Especially, dynamic characteristics were investigated through circular test and circular form machining test is carried out considering many important parameter. Therefore these several experiments is used to be evaluated the model for prediction of circular motion error and circular machined error.

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Fault Diagnosis System of Rotating Machines Using LPC Residual Signal Energy (LPC 잔여신호의 에너지를 이용한 회전기기의 고장진단 시스템)

  • Lee, Sung-Sang;Cho, Sang-Jin;Chong, Ui-Pil
    • Journal of the Institute of Convergence Signal Processing
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    • v.6 no.3
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    • pp.143-147
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    • 2005
  • Monitoring and diagnosis of the operating machines are very important for safety operation and maintenance in the industrial fields. These machines are most rotating machines and the diagnosis of the machines has been researched for long time. We can easily see the faulted signal of the rotating machines from the changes of the signals in frequency. The Linear Predictive Coding(LPC) is introduced for signal analysis in frequency domain. In this paper, we propose fault detection and diagnosis method using the Linear Predictive Coding(LPC) and residual signal energy. We applied our method to the induction motors depending on various status of faulted condition and could obtain good results.

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Parameter Identification and Error Analysis of Approximation method for Linear motors (리니어 모터의 매개변수 추정과 근사화의 오차 분석)

  • Nam, Jae-Wu;Oh, Joon-Tae;Kim, Gyu-Sik
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.49 no.4
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    • pp.61-68
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    • 2012
  • In this paper, a closed-loop sensorless stroke control system for a linear compressor has been designed. In order to estimate the piston position accurately, motor parameters are identified as a function of the piston position and the motor current. These parameters are stored in ROM table and used later for the accurate estimation of piston position. The identified motor parameters are approximated to the several surface functions in order to decrease memory size. They can also be divided into 2 or 4 subsections to decrease identification errors. The effect of the order of surface functions and division of subsections on identification errors and computation time is analyzed.

Characteristic Analysis of Linear Permanent Magnet Synchronous Motor according to steel and back iron. (철심의 유/무에 따른 직선형 영구 자석 동기 모터의 특성 해석)

  • Jang, Seok-Myeong;You, Dae-Joon;Lee, Sung-Ho;Chioi, Jang-Young;Jang, Won-Bum
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.1054-1056
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    • 2003
  • The slotless Permanent-Magnet Linear Synchronous Motors (PMLSM) have been developed for factory automation, transportation applications, wafer steppers, conveyance system, and so on. The current analysis and design are treated in air-cored PMLSM. This paper presents a design and analysis solutions for the general class of iron-cored Permanent magnet Linear Synchronous motor (PMLSM). In our design and analysis, rotor consisting of permanent magnets and slot less iron-cored coil stator are treated in a uniform way via vector potiential. For one such motor structure we give analytical formulas for its magnetic field, opitimal permanent magnet and winding coil thickness, trust force. We also provide comparisons of three types in Halbach, vertical, and horizontal magnet array.

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Development of Embedded Board-based Differential Driving Robot Platform for Education (임베디드 보드 기반의 교육용 차동 구동 로봇 플랫폼 개발)

  • Choi, Hyeon-Ju;Lee, Dong-Hyun
    • IEMEK Journal of Embedded Systems and Applications
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    • v.17 no.2
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    • pp.123-128
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    • 2022
  • This paper proposes a mobile robot platform for education that can experiment with various autonomous driving algorithms such as obstacle avoidance and path planning. The platform consists of a robot module and a remote controller module, both of which are based on the Arduino Nano 33 IoT embedded board. The robot module is designed as a differential drive type using two encoder motors, and the speed of the motor is controlled using PID control. In the case of the remote controller module, a command to control the robot platform is received with a 2-axis joystick input, and an elliptical grid mapping technique is used to convert the joystick input into a linear and angular velocity command of the robot. WiFi and Zigbee are used for communication between the robot module and the remote controller module. The proposed robot platform was tested by measuring and comparing the linear velocity and angular velocity of the actual robot according to the linear velocity and angular velocity commands of the robot generated by the input of the joystick.

Design and Control of Ultra-precision Dual Stage with Air bearings and Voice coil motor for nm scanning system (나노 정밀도 스캐닝 용 공기베어링과 보이스 코일 모터의 초정밀 이중 스테이지 설계 및 제어)

  • Kim K.H.;Choi Y.M.;Kim J.J.;Lee M.G.;Lee S.W.;Gweon D.G.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1883-1886
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    • 2005
  • In this paper, a decoupled dual servo (DDS) stage for ultra-precision scanning system with large working range is introduced. In general, dual servo systems consist of a fine stage for short range and a coarse stage for long range. The proposed DDS also consists of a $XY\theta$ fine stage for handling and carrying workpieces and one axis coarse stage. Its coarse stage consists of air bearing guide system and a coreless linear motor with force ripple. The fine has four voice coil motors(VCM) as its actuator. According to a VCM's nature, there are no mechanical connections between coils and magnetic circuits. Moreover, VCM doesn't have force ripples due to imperfections of commutation components of linear motor systems - currents and flux densities. However, due to the VCM's mechanical constraints the working range of the fine is about $25mm^2$. To break that hurdle, the coarse stage with linear motors is used to move the fine about 500mm. Because of the above reasons, the proposed DDS can achieve higher precision scanning than other stages with only one servo. With MATLAB's Sequential Quadratic Programming (SQP), the VCMs are optimally designed for the highest force under conditions and constraints such as thermal dissipations due to its coil, its size, and so on. And for their movements without any frictions, guide systems of the DDS are composed of air bearings. To get precisely their positions, a linear scale with 5nm resolution are used for the coarse stage's motion and three plane mirror laser interferometers with 5nm for the fine's $XY\theta$ motions. With them, on scanning the two stages have same trajectories. The control algorithm is named Parallel method. The embodied ultra-precision scanning system has sub 100nm following error and in-positioning stability.

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Implementation of Position Sensorless Stroke Controller of Linear Compressors with Motor Parameter Identification (매개변수 추정기를 갖는 리니어 컴프레서의 위치센서리스 스트로크 제어기 구현)

  • Kim, Kwang-Ho;Nam, Jae-Woo;Kim, Gyu-Sik
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.10
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    • pp.173-179
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    • 2014
  • In this paper, a motor parameter identification system has been implemented to improve the performance of the position sensorless stroke controller for linear compressors. In order to control the cooling capability of a refrigerator or an air conditioner in which linear compressors are applied, the piston speed should be controlled. The piston speed control can be obtained by adjusting the frequency or the stroke of linear motors. The dynamic performance of linear compressors depends on how accurately the stroke or the piston amplitude is estimated. The merits and demerits of Constant method and PIM (Parameter Identification Method) concerning the needed memory space and the stroke error are discussed and verified via some experimental studies.

A Study of Dynamic Performance Improvement of Linear Compressors Using Phase Control Loop (리니어 컴프레서의 위상제어를 통한 동특성 향상에 관한 연구)

  • Nam, Jae-Woo;Oh, Joon-Tae;Kim, Gyu-Sik
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.3
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    • pp.156-163
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    • 2014
  • In this paper, a phase control system has been implemented to improve the dynamic performance of the stroke response for linear compressors. In order to control the cooling capability of a refrigerator or an air conditioner in which liner compressors are applied, the piston speed should be controlled. The piston speed control can be obtained by adjusting the frequency or the stroke of linear motors. The dynamic performance of linear compressors depends on how accurately the stroke or the piston amplitude is estimated. A phase control system is added to the stroke control loop and the superior performance of the phase control system is verified via some simulation studies.