• Proceedings of the KIEE Conference
• /
• 1999.11c
• /
• pp.527-529
• /
• 1999

본 논문에서는 압전 구동기의 모델링과 진상-지상 보상기를 이용한 정밀 위치 제어 시스템을 제안한다. 최근 압전 구동기는 고속, 고정밀도가 요구되는 분야에 널리 응용되고 있으나 압전 소자의 히스테리시스 현상으로 인하여 폐루프 제어가 어렵다. 압전 구동기는 개루프 제어 특성이 우수하지만 최근의 X-Y 스테이지나 반도체 공정과 같은 높은 정밀도가 요구되는 작업에서 필요한 성능을 얻기 위해서는 폐루프 제어가 수행되어져야 한다. 따라서 위치 피드백을 이용한 폐루프 제어를 위해 선형 압전 이론으로부터 압전 구동기의 모델링을 정립하고 이 모델로부터 진상-지상 보상기를 설계하며 제어기의 성능을 검토하기 위하여 모의 실험 결과를 보인다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.41-45
• /
• 1997

To design a control system, it is a elementary point that the stability of the system should be guaranteed. Also, the phase of the system plays an important role for its frequence performance. In this paper, we present two stability criterion of repetitive control system with phase-lead and lag compensator. First, the stability criterion for the servo control system with phase-lead and lag compensator is shown by using small-gain theorem. Second, for the repetitive control system with the compensator, the stability criterion, also, is determined by using small-gain theorem. Two stability criterions show the same results that the stability depends on a coefficient of the phase-lead and lag compensator under some condition in servo control system and repetitive control system.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.14 no.5
• /
• pp.598-603
• /
• 2004

An optical head actuator of an optical disk drive consists of two servo mechanisms for the focusing and the tracking to acquire data from disk. As the rotational speed of the disk grows, the utilized lag-lead-lead compensator has known to be above its ability for precisely controlling the optical head actuator. To overcome the difficulty, this paper propose a new controller design method for optical head actuator based fuzzy proportional-integral-derivative (PID) control and the genetic algorithm(GA). It employs a two-stage control structure with a fuzzy PI and a fuzzy PD control and is optimized by the GA to yield the suboptimal fuzzy PID control performance. It is shown the feasibility of the proposed method through a numerical tracking actuator simulation.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.7
• /
• pp.1307-1313
• /
• 1992

The end-point position control of a flexible manipulator is a non-minimum phase system. The PD feedback of the end-point position is not stable in contrast with that of the hub jangle. However, the system can be stabilized conditionally by the feedback of both the hub rate angle and the end-point position. Even in the non-minimum system, the LQG/LTR control law is more systmatic controller design method than the classical control law which uses a root-locus technique.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.5
• /
• pp.837-844
• /
• 2017

The weir to regulate water level in a tide generation tank is above and below carried by two electric cylinders which are mounted on right and left of weir itself. In this case, a movement difference between right and left cylinder causes unbalance of weir and friction between weir and guide. And then, the weir will not be sent to target point. In this study, a synchronous control system is developed to take accurate and quick equilibrium of the weir. The control system based on cross coupled structure consists of two I-PD controllers and a lead compensator. Each of the I-PD controllers is designed in order that the electric cylinder may exactly follow the reference signal without overshoot and input saturation. And the lead compensator is designed to achieve stable and accurate synchronization. Finally, the simulation result shows that the designed synchronous control system is effective for elimination of synchronous error.

• Proceedings of the KIPE Conference
• /
• 2017.11a
• /
• pp.29-30
• /
• 2017

본 논문에서는 7상 BLDC 전동기를 이용한 수중 부하 시스템에서 전동기의 고속 운전 영역 확장을 위한 자동 진상각 알고리즘을 제안한다. 고속 운전 영역 운전 시 역기전력 상승에 따라 전류 지연 현상이 발생한다. 이를 보상하기 위해 기존의 제어 방식은 Look-Up Table을 이용한 진상각 방식 또는 추가적인 하드웨어를 구성하여 제어한다. 이는 운전점이 변경될 경우 제어 특성이 현저히 나빠지고, 전동기의 제정수에 의존적이고, 제어 시스템의 부피 및 비용 증가와 같은 문제를 야기 시킨다. 본 논문은 진상각 인가를 통해 확보할 수 있는 유효 전압을 계산하고 안티와인드업 출력 전압을 이용하여 필요한 진상각을 자동적으로 인가한다. 본 논문에서 제안하는 방식은 컴퓨터 시뮬레이션을 통해 비교 및 분석하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.189-193
• /
• 1996

Piezoelectric actuator is widely used in precision positioning applications due to its excellent positioning resolution. However, serious hysteresis nonlinearity of the actuator deteriorates its open loop positioning capability. Generally, a nonlinear hysteresis model is used in feedforward loop to improve positioning accuracy. In this study, however, a simple lead compensator is proposed as a substitution for a complex nonlinear hysteresis model and tested through experiments for precision position control.

• New & Renewable Energy
• /
• v.8 no.4
• /
• pp.13-20
• /
• 2012

This paper describes a transformerless static synchronous campensator (STATCOM) system based on cascade H-bridge multilevel inverter with star configuration. It is designed not only for the dynamic and continuous compensation of the reactive power but also for the improvement of power quality of existing wind power plant. Especially, when the induction generator of wind turbine is directly connected to the grid, reactive power are occurred by exiting current. so a reactive power compensation system based on the cascade H-bridge multilevel STATCOM is proposed because the output power quality and controllability of reactive power are required by grid code in many different countries. Using various The proposed reactive power control strategy using a STATCOM is compared with the conventional scheme using fixed-size of capacitor bank through various simulation results.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.2
• /
• pp.139-148
• /
• 1997

본 논문에서는 비선형 마찰이 존재하는 조준경 안정화 시스템에 대해서 마찰력 보상과 성능개선을 위한 신경망제어기의 설계방법을 제시한다. 제안한 신경망제어기는 비례, 적분, 진상(PI/LEAD) 제어기와 신경회로망과의 병렬로 구성되며, 제어 목적은 비선형 마찰과 외란이 존재하여도 안정거울의 각속도 추적성능과 안정화 성능의 향상에 있다. 신경회로망의 입력으로 안정거울의 각속도 추적오차와 추적오차의 적분, 제어입력이 필터를 통과한 신호가 사용되며, 신경호로망은 간접학습구조에 의해 학습된다. 조준경 시스템의 비선형 마찰력인 쿨롱마찰력의 크기가 외부환경에 따라 변하는 경우와 시스템으로 외란이 인가되는 경우에 대하여도 제안한 병렬제어기는 기존의 PI/LEAD 제어기보다 추적과 안정화 성능면에서 우수함을 컴퓨터 모의 실험으로 확인한다.

• Journal of Power System Engineering
• /
• v.13 no.6
• /
• pp.129-136
• /
• 2009

A motor cylinder is widely used as an apparatus for transportation of a small scale load. It is, however, difficult for only one motor cylinder to transfer a large scale load such as a weir. The large scale load is transferred by two motor cylinders which are mounted on right and left of load itself. In this case, the displacement difference generated between two motor cylinders, namely, the synchronous error has a bad influence on the transportation. In this study, a synchronous control system is designed to restrain synchronous error caused by skew disturbance. The control system is composed of two disturbance observers and one synchronous controller. Each disturbance observer is designed to restrain the skew disturbance. And the synchronous controller is designed to achieve stable and accurate synchronization. Finally, the simulation results show that the designed control system is effective for the skew disturbance which lead to synchronous error.