• Title/Summary/Keyword: servo mechanism

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Design of a Dual-Drive Mechanism for Precision Gantry

  • Park, Heung-Keun;Kim, Sung-Soo;Park, Jin-Moo;Daehie Hong;Cho, Tae-Yeon
    • Journal of Mechanical Science and Technology
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    • v.16 no.12
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    • pp.1664-1672
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    • 2002
  • Gantry mechanisms have been widely used for precision manufacturing and material handling in electronics, nuclear, and automotive industries. Dual-drive servo mechanism is a way to increase control bandwidth, in which two primary axes aligned in parallel are synchronously driven by identical servo motors. With this mechanism, a flexible coupling (compliance mechanism) is often introduced in order to avoid the damage by the servo mismatch between the primary drives located at each side of gantry. This paper describes the design guidelines of the dual-drive servo mechanism with focus on its dynamic characteristics and control ramifications. That is, the effect on the system bandwidth which is critical on the system performance, the errors and torques exerted on guide ways in case of servo mismatch, the vibration characteristics concerned with dynamic error and settling time, and the driving force required at each axis for control are thoroughly investigated.

A Study on the Characteristics of the Compact Hydraulic Servo Mechanism for Proportional Position Control (비례 위치 제어용 소형 유압 서보 기구의 특성에 관한 연구)

  • Lee, Seung-Hyun;Song, Chang-Seop
    • Tribology and Lubricants
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    • v.18 no.1
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    • pp.49-54
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    • 2002
  • In this study, the characteristics of the hydraulic servo mechanism for proportional position control of a hydraulic construction eguipment were analyzed using the developed analysis tool. The result were used in the others hydraulic system except construcdtion eguipment to improve the static performance of the system, the system parameter effects on the controllable region and the hydraulic servo mechanism variation were studied.

The Design of Servo Control Mechanism for Swash Plate Type Axial Piston Pump (사판식 피스톤 펌프 서보제어기구 설계)

  • 노종호;함영복;윤소남;최병오
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.741-744
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    • 2002
  • The closed circuit pump is applied to control rotating speed and direction of hydraulic motor in hydrostatic transmission. To development of this pump, first of all the servo control regulator has to be designed. Mechanical-hydraulic type servo control mechanism is excellent to be compared with electronic-hydraulic type servo control valve to reliability and economy. In this paper to development positive and negative variable displacement type servo regulator, the hydro-mechanical servo control mechanism is calculated and designed with force balance of pilot piston and position feedback of servo piston.

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Experimental Analysis of Axial Vibration in Slim-type Optical Disc Drive (슬림형 광 디스크 드라이브의 축방향 진동에 대한 실험적 해석)

  • 박대경;전규찬;이성진;장동섭
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.694-699
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    • 2002
  • As the demand for slim laptops requires ion'-height optical disc drives, vibration problems of optical disc drives are of great concern. Additionally, with the decrease of a track width and a depth of focus in high density drives, studies on vibration resonance between mechanical parts become more important. From the vibration point of view, the performance of optical disc drives is closely related with the relative displacement between a disc and an objective lens which is controlled by servo mechanism. In other words, to read and write data properly, the relative displacement between an optical disc and an objective lens should be within a certain limit. The relative displacement is dependent on not only an anti-vibration mechanism design but also servo control capability. Good servo controls can make compensation for poor mechanisms, and vice versa. In a usual development process, robustness of the anti-vibration mechanism is always verified with the servo control of an objective lens. Engineers partially modify servo gain margin in case of a data reading error. This modification cannot correct the data reading error occasionally and the mechanism should be redesigned more robustly. Therefore it is necessary to verify a mechanism with respect to the possible servo gain plot. In this study we propose the experimental verification method far anti-vibration mechanism with respect to the existing servo gain plot. This method verifies axial vibration characteristics of optical disc drives on the basis of transmissibility. Using this method, we verified our mechanism and modified the mechanism for better anti-vibration characteristics.

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Experimental Analysis of Axial Vibration in Slim-type Optical Disc Drive (슬림형 광 디스크 드라이브의 축방향 진동에 대한 실험적 해석)

  • 박대경;전규찬;이성진;장동섭
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.11
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    • pp.833-839
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    • 2002
  • As the demand for slim laptops requires low-height optical disc drives, vibration problems of optical disc drives are of great concern. Additionally, with the decrease of a track width and a depth of focus in high density drives, studies on vibration resonance between mechanical parts become more important. From the vibration point of view, the performance of optical disc drives is closely related with the relative displacement between a disc and an objective lens which is controlled by servo mechanism. In other words, to read and write data properly, the relative displacement between an optical disc and an objective lens should be within a certain limit. The relative displacement is dependent on not only an anti-vibration mechanism design but also servo control capability. Good servo controls can make compensation for poor mechanisms, and vice versa. In a usual development process, robustness of the anti-vibration mechanism is always verified with the servo control of an objective lens. Engineers partially modify servo gain margin in case of a data reading error. This modification cannot correct the data reading error occasionally and the mechanism should be redesigned more robustly. Therefore it is necessary to verify a mechanism with respect to the possible servo gain plot. In this study we propose the experimental verification method for anti-vibration mechanism with respect to the existing servo gain plot. Thismethod verifies axial vibration characteristics of optical disc drives on the basis of transmissibility. Using this method, we verified our mechanism and modified the mechanism for better anti-vibration characteristics.

High Speed Tool Feed System by the Mechanism of Ball Screw and Servo Motor (볼 나사와 서보모터 메커니즘에 의한 고속 TOOL 이송장치)

  • 김성식;김경석
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.11
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    • pp.76-82
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    • 1998
  • In this study, the Ball screw and Servo motor Mechanism is considered as a High Speed Tool Feed System for the machining of a piston of a reciprocating engine. For the machining of a piston, that shapes oval, high speed servo mechanism is needed as a positioning of a cutting tool, and the stroke of tool is 0.1 mm ~ 1 mm. Ball screw and servo motor Mechanism is available very much because this mechanism is used widely in general machine. This Mechanism has been designed with the use of the decrease in mass and partial wear of the ball screw for high speed positioning of tool. Also the periodic learning control method with the inverse transfer function compensation has been applied to the positioning control for the high accuracy positioning of tool. These applications lead the achievement of the machining of a piston with an accuracy of 5${\mu}{\textrm}{m}$ at 2500 rpm in CNC turning.

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Design of a VCM actuator for dual servo system

  • Choi, Hyeun-Seok;Han, Chang-Soo;Kim, Seung-Soo;Kim, Eung-Zu;Choi, Tae-Hoon;Na, Kyoung-Hwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.301-306
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    • 2004
  • In this study, Dual servo mechanism with VCM(Voice Coil Motor) and PZT is designed for a high precision force and position control. We designed the VCM actuator and dual servo mechanism with leaf spring. VCM actuators, with their high linearity, simple structure, low weight, and high efficiency, are increasingly being used in micro-positioning applications. There are many kinds of VCM with a structure. VCM actuators are divided into two types by moving parts. One is moving magnet type and the other moving coil type. We described the properties of these two types of VCM. Design parameters of VCM are defined through the FEM simulation analysis of magnetic field and dynamic model of dual servo mechanism. These researches help to for decreasing loss in the air gap of VCM. We present dual servo mechanism is effective mechanism for a force control in hi h precision, properties of designed VCM.

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Characteristic Analysis and Experiment of Pneumatic Servo Valve (공기압 서보밸브 특성해석 및 실험)

  • Kim, Dong-Soo;Lee, Won-Hee;Choi, Byung-Oh
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.967-973
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    • 2004
  • Electro-pneumatic servo valve is an electro-mechanical device which converts electric signals into a proper pneumatic flow rate or pressure. In order to improve the overall performance of pneumatic servo systems, electro-pneumatic servo valves are required, which have fast dynamic characteristics, no air leakage at a null point, and can be fabricated at a low-cost. The first objective of this research is to design and to fabricate a new electro-pneumatic servo valve which satisfies the above-mentioned requirements. In order to design the mechanism of the servo valve optimally, the flow inside the valve depending upon the position of spool was analyzed variously, and on the basis of such analysis results, the valve mechanism, which was formed by combination of the spool and the sleeve, was designed and manufactured. And a tester for conducting an overall performance test was designed and manufactured, and as a result of conducting the flow rate test, the pressure test and the frequency test on the developed pneumatic servo valve.

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Development of Direct Drive type Pneumatic Servo Valve (직동식 공기압 서보밸브 개발)

  • Kim, Dong-Su;Lee, Won-Hui;Choe, Byeong-O
    • 연구논문집
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    • s.34
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    • pp.69-77
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    • 2004
  • Electro-pneumatic servo valve is an electro-mechanical device which converts electric signals into a proper pneumatic flow rate or pressure. In order to improve the overall performance of pneumatic servo systems, electro-pneumatic servo valves are required, which have fast dynamic characteristics, no air leakage at a null point, and can be fabricated at a low-cost. The objective of this research is to design and to fabricate a new electro-pneumatic servo valve which satisfies the above-mentioned requirements. In order to design the mechanism of the servo valve optimally, the flow inside the valve depending upon the position of spool was analyzed variously, and on the basis of such analysis results, the valve mechanism, which was formed by combination of the spool and the sleeve, was designed and manufactured. Further, the performance of pneumatic servo valve has been verified through an overall performance test on the developed product.

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Designing Compensators of Dual Servo System For High Precision Positioning (초정밀 위치 제어를 위한 이중 서보 시스템의 보상기 설계)

  • Choi, Hyeun-Seok;Song, Chi-Woo;Han, Chang-Soo;Choi, Tae-Hoon;Lee, Nak-Kyu;Na, Kyung-Whan
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1309-1314
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    • 2003
  • The high precision positioning mechanism is used in various industrial fields. It is used in semiconductor manufacturing line, test instrument, Bioengineering, and MEMS and so on. This paper presents a positioning mechanism with dual servo system. Dual servo system consists of a coarse stage and a fine motion stage. The course stage is driven by VCM and the actuator of fine stage is the PZT. The purposes of dual servo system are stability, higher bandwidth, and robustness. Lead compensator is applied to this control system, and is designed by PQ method. Designed compensator can improve property of positioning mechanism.

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