• International Journal of Aerospace System Engineering
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• 제5권2호
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• pp.8-15
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• 2018

For small earth observation satellites, alignment between the optical components is important for precise observation. However, satellite cameras are structurally subject to misalignment in the launch environment where vibration excitations and impacts apply, and in space environments where zero gravity, vacuum, radiant heat and degassing occur. All of these variables can cause misalignment among the optical components. The misalignment among optical components results in degradation of image quality, and a re-alignment process is needed to compensate for the misalignment. This process of re-alignment between optical components is referred to as a refocusing process. In this paper, we proposed a 3 - axis focusing mechanism to perform the refocusing process. This mechanism is attached to the back of the secondary mirror and consists of three piezoelectric inertia-friction actuators to compensate the x-axis, y-axis tilt, and de-space through three-axis motion. The fabricated focus mechanism demonstrated excellent servo performance by experimenting with PD servo control.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.319.1-319
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• 2002

A frequency-domain PES estimation and its prediction method are proposed for the tightly-coupled servo/mechanical design of high-TPI HDD system above 100kTPI. The major two disturbance energies which are related with mechanical vibrations inside of HDD are used to predict the drive-level PES, while considering closed-loop servo dynamics. One is the torque disturbance which mainly comes from aerodynamic excitation of HSA system and the other is the displacement disturbance from disk-spindle dynamics. (omitted)

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.911-916
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• 1991

Spent nuclear fuel is highly radioactive and requires remote operation due to radiation exposure. Motors which have been used in the highly radioactive environments are a DC type because of their easy implementation on control system. However there are some problems such as mechanical maintenance of brush and commutator, high cost, and heavy material control. AC servo motors are applied and tested on fuzzy and conventional control algorithms. Fuzzy logic controls of AC servo give adequate control accuracy and power for spent fuel handling in radioactive environments.

• 한국인쇄학회지
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• 제21권2호
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• pp.11-20
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• 2003

In Flexo printing machine, it's operated with combination of blanket cylinder and cylinder. The blanket cylinder has some number of grooves to attach the blanket on surface. In case of operating the printing machine, it has generate mechanical noise when the two cylinders encounter with the grooves. So, in this study, we developed a mechanical noise control algorithm of printing in servo control system. Then we have reduced the mechanical noise with control of servo actuator.

• 대한기계학회논문집A
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• 제21권10호
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• pp.1619-1625
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• 1997

This paper concerns a 2-axis PR type pneumatic manipulator system translating in vertical and rotating in horizontal directions. A simplified linear model is mathematically formulated similar to the pneumatic acturators in dynamic responses in order to devise an appropriate position control scheme. A PD controller preceding the on/off solenoid valve turns out not only economical but also effective in reducing rise time and amplitude of limit cycles, if its control gains are determined on the basis of frequency response. And, additional implementation of symmetric or asymmetric deadband at the PD controller output greatly helps minimize valve opening numbers, positional error, and undesirable direction-dependent property due to the gravitational load. Such a control concept is synthesized through numerical simulations and next applied to the experimental set-up, featuring enhanced positional servo characteristics.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1109-1114
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• 2007

This paper presents the road simulator control technology for reproducing the road input signal to implement the real road data. The simulator consists of the hydraulic pump, servo valve, hydraulic actuator and its control equipment. The QFT is utilized to control the simulator effectively. The control system illustrates a tracking performance of the closed-loop controller with low order transfer function G(s) and pre-filter F(s) for a parametric uncertain model. A force controller is designed to communicate the control signal between simulator and digital controller. The efficacy of the QFT force controller is verified through the numerical simulation, in which combined dynamics and actuation of the hydraulic servo system are tested. The simulation results show that the proposed control technique works well under uncertain hydraulic plant system. The conventional software (Labview) is used to make up for the real controller in the real-time basis, and the experimental works show that the proposed algorithm works well for a single road simulator.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2226-2230
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• 2005

The Advanced Spent Fuel Conditioning Process (ACP), which is a pre-disposal treatment process for spent fuel is being developed at the Korea Atomic Energy Research Institute (KAERI). The ACP equipment is operated in an intense radiation field as well as in a high temperature. Thus, the equipment is designed in consideration of the remote handling and maintenance. This paper describes a Bridge Transported Bilateral Force-Reflecting Servo-Manipulator (BTSM) system, which is being developed to overcome the limitation of access that is a drawback of the mechanical Master-Slave Manipulators (MSMs), which are mounted on the ACP hot cell wall for the operation and the maintenance of the ACP equipment. The BTSM system was manufactured and temporally installed at the mockup to test its performance. The manufactured BTSM system will be installed at the ACP hot cell on June 2005 after the accomplishment of the performance test. The BTSM system consists of four components: a transporter with a telescoping tubeset, a slave manipulator, a master manipulator, and a remote control system. This system will highly increase the volume of coverage for the operation and maintenance of the ACP equipment.

• Journal of Power Electronics
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• 제15권5호
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• pp.1409-1420
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• 2015

In this paper, an algorithm using two bi-quad filters to suppress the wide-band resonance for PMSM servo systems is proposed. This algorithm is based on the double bi-quad filters structure, so it is named, "double bi-quad filter." The conventional single bi-quad filter method cannot suppress unexpected mechanical terms, which may lead to oscillations on the load side. A double bi-quad filter structure, which can cancel the effects of compliant coupling and suppress wide-band resonance, is realized by inserting a virtual filter after the motor speed output. In practical implementation, the proposed control structure is composed of two bi-quad filters on both the forward and feedback paths of the speed control loop. Both of them collectively complete the wide-band resonance suppression, and the filter on the feedback path can solve the oscillation on the load side. Meanwhile, with this approach, in certain cases, the servo system can be more robust than with the single bi-quad filter method. A step by step design procedure is provided for the proposed algorithm. Finally, its advantages are verified by theoretical analysis and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.179-181
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• 2003

Conventional P/PI speed controller of today's servo drives should be manually tuned the controller switching set-point by trial-and-errors, which may translate the drive system down-time and loss of productivity. The adjustable drive performance is heavily dependent on the qualify of the expert knowledge and becomes inadequate in applications where the operating conditions change in a wide range, i.e., tracking command, cceleration/deceleration time, and load disturbances. In this paper, the demands on simple controls/setup are discussed for industry servo drives. Analyzing the frequency content of motor torque command, P/PI control mode switching is automatically peformed with some prior knowledge of the mechanical dynamics. The dynamic performance of the proposed scheme assures a desired tracking response curve with minimal oscillation and settling time over the whole operating conditions. For comprehensive comparison of traditional P/PI control scheme, extensive test is carried out on actual servo system.

• 한국전자통신학회논문지
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• 제13권6호
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• pp.1243-1248
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• 2018

금속분말 야금은 금속이나 금속산화물의 분말을 금형에 넣어 프레스로 압축 성형한 후에 고온으로 가열 소결하면 굳어지는 현상을 이용하여 독특한 모형의 부품이나 일정한 형태의 제품을 만드는 제조 기술이다. 분말 야금 프레스 장비는 자동차, 전자 부품 등의 핵심 정밀 부품을 만드는데 사용되기 때문에 이를 위하여 정밀한 서보 모터를 사용하여 제작되는 경우가 대부분이다. 본 논문에서 설계 및 구현한 지능형 정밀 서보제어 분말 성형 프레스 시스템은 상부 램 부분은 기계식 캠축을 사용하고 하부 램 부분은 고정밀 서보 시스템을 활용하여 정밀하게 제어함으로써 가격대를 낮추면서도 정밀도를 유지할 수 있는 장점을 가진다. 또한 OPC 기반의 모니터링 및 공정 데이터 수집 시스템을 설계 및 구현함으로써 향후 빅 데이터를 활용한 스마트 제조 관리 시스템에 적용될 수 있는 확장성을 제공한다.