• Title/Summary/Keyword: Ballscrew

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Improvement of Microstep Characteristics in Hydrostatic Table with Ballscrew (볼스크류로 구동되는 유정압테이블의 미소이송특성 향상)

  • 황주호;박천홍;이찬홍;이후상
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.1
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    • pp.94-100
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    • 1998
  • Microstep characteristics largely depends on the variation of friction force induced by the geometric accuracy of ballscrew, guide rail and the control characteristics of servo unit. In this paper, for improving the microstep characteristics of hydrostatic table with ballscrew, microstep resolution according to the control mode of servo amplifier and response characteristic by the variation of integral gain are tested and compared. Relationship between micro motion behavior of hydrostatic table and the output torque is also tested for acquiring the effective variables on control characteristics. From the results. it is confirmed that the torque control mode has a advantage in microstep resolution, and more stable than velocity control mode in low feed rate, and by the increase of integral gain in the elastic motion realm, response characteristics can be improved.

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Precision Position Control of Feed Drives (이송기구의 정밀 위치제어)

  • 송우근;최우천;조동우;이응석
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.266-272
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    • 1994
  • An essential ingredient in precision machining is a positioning system that responds quickly and precisely to very small input signal. In this paper, two different positioning systems were presented fot the precision positioning control. The one is a friction drive system, the other is a ballscrew system. The friction drive system was composed of an air sliding guide and a friction drive. The ballscrew system was made of a ballscrew and a linear guide. Nonlinear behaviors of the given systems tend to make the system inaccurate. The paper looked at the phenomena that has caused the positioning error. These apparently nonlinear phenomena can be attributed mainly to the presence of the nonlinear friction and slip effect plus the dynamic change from the microdynamic to the macrodynamic and form the macrodynamic to the microdynamic. For the control of the positioning system, the control algorithm based on a neural network is suggested. The FEL(Feedback Error Learning) controller can learn the inverse dynamics of a nonlinear system by using the neural network controller, and stabilize the system by a linear controller. In the experiment, PTP control is implemented withen the maximum error of 0.05 .mu.m ~0.1 .mu. m when i .mu.m step reference input is applied and that of maximum 1 .mu. m when 100 .mu.m step reference input is given. Sinusoidal inputs with the amplitude of 1 .mu.m and 100 .mu. m are used for the tracking control of the positioning system. Experimental results of the proposed algorithm are shown to be superior to those of conventional PD controls.

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Modeling of Feed Drive System Considering Combined Stiffness with Longitudinal And Twist Direction (볼스크류의 축-비틀림 복합강성을 고려한 이송계 모델링)

  • 이찬홍;박천홍;노승국;이후상
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.387-390
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    • 2002
  • In machine tools, the stiffness of feed drive system is very important for high speed and accurate operation. The ball screw driven feed system has small friction, so the longitudinal and twist stiffness are connected directly and affected by each other. As the longitudinal and twist stiffness are participated in total stiffness of feeding system by about ratio of 4:1, the combined stiffness is necessary to compute when stiffness of feed system is estimated. In this paper, calculation of this combined stiffness is derived and applied for an actual ballscrew fled drive system. The static stiffness and 1 st natural frequency of the feed system is measured, and it is proved the difference between estimation and experiment result is less than 6%.

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Development of a New Climbing Mechanism for Inter-Block Welding in Shipbuilding (선체 블록내 용접을 위한 새로운 승월 메커니즘 개발)

  • 정원지;김기정;김성현;박명환;신기수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.434-437
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    • 2004
  • This paper presents the development of a new climbing mechanism for inter-block welding in Shipbuilding. The climbing mechanism is that it is career type of robot that can pass over block interval for welding of interblock in shipbuilding. The point part of mechanism is that move ballscrew. The Ballscrew`s capacity account and dynamic analysis of leg part are achieved through this paper. Force and torque analysis were achieved by simulation. This can have strong point in side of cost-cutting and welding amount of work than existent method.

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A Experiment of the damping effect for Electromagnetic Damper using DC Motor and Ballscrew (DC Motor와 Ballscrew를 이용한 Electromagnetic Damper Damping 효과 실험)

  • Kang, Jeong-Ho;Lee, Hac-Choel;Jeong, Young-Suk
    • Proceedings of the KIPE Conference
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    • 2008.06a
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    • pp.124-126
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    • 2008
  • In this Paper, the modeling of the electromagnetic damper for automobile suspension is presented and the validation of the model is demonstrated by experiments. An electromagnetic damper, composed of a rotary DC motor, and a ball screw and nut. The damper then operates as a linear electric actuator. The damper then operate as a linear electric actuator. The results indicate the proposed system is feasible and it is proved that the electromagnetic damper has better than oil damper of passive control system.

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Tip vibration control of a single-link flexible robot arm under translational motion

  • Lee, Seong-Cheol;Cheong, Hoon;Chonan, Seiji;Inooka, Hikaru
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10b
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    • pp.607-612
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    • 1992
  • This paper presents a tip position control of a single-link flexible arm with a payload by using closed loop control. The shifting problem of the arm from the initial position to desired position is considered by the variation of the displacement gain $G_{p}$ and velocity gain $G_{v}$. The system is composed of a flexible arm with payload, DC servomotor, and a ballscrew mechanism. The flexible arm is mounted on a mobile stage driven by a servomotor and ballscrew. As a result, the increase of the displacement and velocity gain respectively comes to the reduction of tip vibration. Theoretical results are approximately in good agreement with those obtained experimentally.y.y.

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선단 부하를 갖는 병진운동 단일 링크 탄성암 선단의 closed-loop 제어

  • 정훈;이성철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1992.04a
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    • pp.185-189
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    • 1992
  • This paper prsents an end-point control of a one-link flexible arm with a payload by using closed loop control. Tip position of arm is shifted by the base motion according to DC servomotor, whivh is driven by a feedback signal composed of the tip displacement and the estimated tip velocity. The shifting problem of the arm from initial position to desired position is considered by the variation of the displacement gain Gd and velocity agin Gv. Theoretical results are obtained by applying the method of the Laplace transform to the governing equations and the method of numerical inversion. This system is composed of a flexible arm with payload, DC servomotor, and a ballscrew mechanism. The flexible arm is mounted on a mobile stage driven by a servomotor and ballscrew. In controlling the tip displacement of flexible arm, the fundamental bode vibration is supressed more rapidly with an increase of the velocity feedback gain Gv and the feedback displacemenmt gain Gd. Theretical responses are approximately in good agreement with those obtained experimentally.

Thermal Characteristic Analysis of a High-Speed HMC with Linear Motor and Magnetic Bearing (리니어모터와 자기베어링을 채용한 초고속 HMC의 열특성 해석)

  • Kim, S. I.;Lee, W. J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.11-15
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    • 2002
  • This paper presents the thermal characteristic analysis of a high-speed HMC with spindle speed of 50,000rpm. The spindle is supported by two radial and axial magnetic bearings. and the built-in motor is located between the axial and rear radial magnetic bearings. The X-axis and Y-axis feeding systems are composed of linear motor and linear motion guides, and the Z-axis feeding system is composed of servo-motor, ballscrew and linear motion guide. The thermal analysis model of high-speed HMC is constructed by the finite element method, and the thermal characteristics in the design stage are estimated based on the temperature distribution and thermal deformation under the conditions related to the heat generation of built-in motor, magnetic bearings, linear motors, servo-motor, ballscrew, and so on.

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