• Title/Summary/Keyword: servo-control

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Improved Design in Fishing Operation System for Small Inshore and Coastal Fishing Vessels-I -Design of a Automatic Winch System- (소형 연근해 어선의 조업 시스템 개선에 관한 연구-I -자동 권양 윈치 시스템의 설계-)

  • 이대재
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.36 no.1
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    • pp.12-24
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    • 2000
  • The electro-hydraulic servo winch system built in a automatic tension control equipment was designed with a latent need for an advanced system in fishing operations of the inshore and coastal fishing vessels. In order to keep the constant tension condition of warp under loading, a tension control circuit was added to the servo winch system.The dynamic performance in the open loop behaviour of the designed winch system was investigated and its applicability was tested for various possibilities of load using a load generator especially developed in order to this study.The mechanical characteristics of this system is different from that of a conventional type, that is, the tension, length, line speed and drum revolution can be automatically controlled by the information from various sensors, such as torque, rpm and pressure transducers. from the experiment results, it was verified that the servo winch system has very good output and tracking behaviour for the control input signals in different operating conditions though overshoot of out 8% in the transient characteristics of torque under the load though a overshoot of about 8% in the transient characteristics of torque under the load condition can be observed when the opening of servo valve, adjustable by the input voltage between - 10 V up to 10 V, changed suddenly.Consequently, the improved fishing winch system can be effectively used as the automatic shooting and hauling equipment of low cost for small inshore and coastal fishing vessels which engage in net fishing.

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Dynamic Modeling and Input Shaping Control of a Positioning Stage (위치결정 스테이지에 대한 동적 모델링과 입력성형 제어)

  • Park, S.W.;Hong, S.W.;Choi, H.S.;Jang, J.W.
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.2
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    • pp.83-89
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    • 2008
  • This paper presents the dynamic analysis and input shaping control of a positioning stage. Vibration characteristics of the positioning stage are affected not only by the structural dynamics but also by the servo actuators that consist of the mechanism; driving motor and controller. This paper proposes an integrated dynamic model to accommodate both the structural dynamics and the servo actuators. Theoretical modal analysis with a commercial finite element code is carried out to investigate the dynamic characteristics of the experimental positioning stage. Experiments are performed to validate the theoretical modal analysis and estimate the equivalent stiffness due to the servo actuators. This paper deals with an input shaping scheme to suppress vibration of the positioning stage. Input shapers are systematically implemented for the positioning stage in consideration of its dynamics. The effects of servo control gain are also investigated. The experiments show that input shaping effectively removes residual vibrations and then improves the performance of positioning stage.

Sliding Mode Control for Servo Motors Based on the Differential Evolution Algorithm

  • Yin, Zhonggang;Gong, Lei;Du, Chao;Liu, Jing;Zhong, Yanru
    • Journal of Power Electronics
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    • v.18 no.1
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    • pp.92-102
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    • 2018
  • A sliding mode control (SMC) for servo motors based on the differential evolution (DE) algorithm, called DE-SMC, is proposed in this study. The parameters of SMC should be designed exactly to improve the robustness, realize the precision positioning, and reduce the steady-state speed error of the servo drive. The main parameters of SMC are optimized using the DE algorithm according to the speed feedback information of the servo motor. The most significant influence factor of the DE algorithm is optimization iteration. A suitable iteration can be achieved by the tested optimization process profile of the main parameters of SMC. Once the parameters of SMC are optimized under a convergent iteration, the system realizes the given performance indices within the shortest time. The experiment indicates that the robustness of the system is improved, and the dynamic and steady performance achieves the given performance indices under a convergent iteration when motor parameters mismatch and load disturbance is added. Moreover, the suitable iteration effectively mitigates the low-speed crawling phenomenon in the system. The correctness and effectiveness of DE-SMC are verified through the experiment.

Robust Servo System Design by $H_2/H_{\infty}$ Control - Application to Three Inertia Benchmark Problem- (혼합 $H_2/H_{\infty}$제어에 의한 강인한 서보시스템의 설계 -3관성 벤치마크문제의 해법 -)

  • Choe, Yeon-Wook
    • Journal of the Institute of Convergence Signal Processing
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    • v.6 no.3
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    • pp.148-156
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    • 2005
  • The purpose of this paper is to propose an approach to design a robust servo controller based on the mixed $H_2/H_{\infty}$ theory, and confirm its validity by applying to a benchmark problem. First, the existing $H_{\infty}$ servo problem is modified to a structure for the mixed $H_2/H_{\infty}$ control problem by virtue of the internal model principle. By making use of proposed structure, we can divide specifications required in the robust servo system design into $H_2$ and $H_{\infty}$ performance criteria, respectively. It is shown that the proposed design approach is quite effective through an application to a three inertia benchmark problem.

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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.

Model Indentification and Discrete-Time Sliding Mode Control of Electro-Hydraulic Systems (전기-유압 서보 시스템의 모델규명 및 이산시간 슬라이딩 모드 제어)

  • 엄상오;황이철;박영산
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.1
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    • pp.94-103
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    • 2000
  • This paper describes the model identification and the discrete-time sliding mode control of electro-hydraulic servo systems which are composed of servo valves, double-rod cylinder and load mass. The controlled plant is identified as a 3th-order discrete-time ARMAX model obtained from the prediction error algorithm, where a nominal model and modeling errors are zuantitatively constructed. The discrete sliding mode controller for 3th-order ARMAX model is designed in discrete-time domain, where all states are observed from Kalman filter. The discrete sliding mode controller has better tracking performance than that obtained from continuous-time sliding mode controller, in experiment.

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A Fine Motion Mechanism of Dual Servo Control for Ultraprecision Positioning (초정밀 위치 결정을 위한 이중 서보 제어용 미세 구동 메카니즘)

  • 오정석;이창우;이형석;김승우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.249-254
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    • 1993
  • In order to respond to the increasing demands of ultraprecision positioning mechanism in the field of precision engineering, more accurate stages are needed whose positioning uncertainty should be in the unprecedented level of nanometers, while maintaining a long travek range. For this application, most conventional stage mechanisms are found not suitable, so the concept of dual servo, which uses two different servos, is one of the new design and control strategies being extensively investigated these days, This paper presents a fine motion mechanism as a part of research on the dual servo control. The stage is made of a single structure of elastic flexure, whose xy .theta. motions are induced in the form of elastic deformation activated by three piezoelectric actuators. Experimental results show that the translational and rotational motions of the stage can be controlled with resolutions of 5 nm and 0.1 arcsec, respectively.

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Development of Servo-system for Straightness Improvement of Linear Motor Stage (리니어모터 스테이지 진직도 향상을 위한 서보 시스템 개발)

  • 강민식;최정덕
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.530-536
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    • 2004
  • In this paper a servo-system is developed to improve straightness of linear motor stages. When a linear motor stage is used for high-precision linear motion systems, high precision straightness accuracy is necessary to meet the required position accuracy. In such cases, machining and assembling cost increases to improve the straightness accuracy. An electro-magnetic actuator which is relatively cost effective than any other conventional servo-systems is suggested to compensate the fixed straightness error. To overcome the compensation error due to the friction, a sliding mode control is applied. The effectiveness of the suggested mechanism and the control performance are illustrated along with some experimental results.

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A Study on the Design and Control Super-Precision Coarse and Fine Positioning Apparatus (초정밀 조미동 위치결정기구의 설계 및 제어에 관한 연구)

  • Kim, J.Y.;Cho, Y.T.;O, S.M.;Park, K.H.
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.10
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    • pp.88-93
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    • 1996
  • The study was carried out development a pricision positioning apparatus, consisting of DG servo motor and piezoelectric actuatior. This system is composed of fine and coarse apparatus, measurement system and control system. Peezoelectric actuator is designed for fine positioning. Coarse positioning using lead screw is droved by DC servo motor. Control system output a signal from laser interfermeter and capacitive sensor to amplifer of DC servo motor and piezoelectric actuator after digital signal processing (DSP). Resolution of this apparatus measure with laser interferometer and microsense

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