• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1944-1946
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• 2008

This paper analyzed orientation simulation of Stewart platform which is a parallel manipulator of 6-DOF. When platform shape had been given, inverse kinematics as the problem about length of actuator could get an answer using a vector function simply, and forward kinematics as the problem solving shape of platform through the length of actuator could get answer using repetitive and manual explaining Newton-Raphson method because it is expressed a high nonlinear polynomial expression. In addition, for control the Stewart platform it could drive simply and it could confirm the state of orientation in real-time.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.103-110
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• 2006

Automatic optical alignment modules are a key technology in optical communication system. However, the optic component assembly depends highly on manual or semi-automated alignment process. In this paper, a novel alignment mechanism with minimum degree-of-freedom has been designed and theoretical models are derived from geometric optical characteristics on collimators, optical filters and optical ray alignment. The automatic alignment control algorithm has been newly developed based on the mechanism and models, and then we make fast, precise and reliable alignment through the algorithm. The reliability of developed modules has been verified with various simulations and performance evaluations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.110-110
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• 2004

하나 또는 다수개의 압전액츄에이터(piezoelectric actuator)로 구성된 시스템에서 구동 효율을 높이는데 직접적인 영향을 미치는 고정밀과 빠른 응답 특성을 구현(implementation)하기 위하여, 입력전압에 대하여 출력전압이 선형적으로 추종하고 주파수 가변(variable)이 독립적이며 순차적으로 제어가 가능한 위상가변(phase shifting)형 압전액츄에이터 구동장치의 설계가 필요하다. 구동신호론 증폭하고 가변하는 고전압 증폭 구동장치는 압전액츄에이터 구동에 직접 영향을 주게 되므로, 이의 특성인 고주파에서의 위상지연 보상, 높은 회전비(slew rate)로 고전압에서 정현파의 찌그럼짐을 방지, 전압이득의 가변 및 안정화, 입력 및 출력 임피던스의 개선과 주파스 대역폭(band width)의 확장 등은 매우 중요하다.(중략)

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.314-316
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• 2001

This paper present the position control method for the application of permanent magnet linear synchronous motor. Controller is designed as a conventional P-PI controller, but the extra information is used such as velocity and acceleration from motion profiles. The profiles comes from S-Curve which is an optimized point-to-point motion profiles to achieve fast motions with minimum vibration[2]. In this application, the targets of the position control are maximum 10um position error within 10msec after respective ending point of position profiles. The implementation of the controller has been done in full digital way. All the controller is designed on the DSP TMS320VC33 control board. To prove performance of the controller, the experiment was performed with a servo linear motor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.452-456
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• 2002

The sensor based control system has some sensor fault while operating in the field. In this paper, a sensor fault detection and reconstruction system for a sun tracking controller has been researched by using polynomial regression and principle component analysis approach. The developed sun tracking system controls tow actuators with sensor based mechanism as on-line control and sun orbit information as off-line control, alternatively. To show the validity of the developed system, several experiments were illustrated.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.5
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• pp.44-51
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• 2008

In this paper, the optimal tuning of a cross-coupled controller linked with the feedforward controller is studied to reduce contouring and tracking errors of a bi-axial servomechanisms by using the previously developed integrated tuning method. The CCC system for an arbitrary curve, which is combined with the feedforward controller, is formulated by a state-space based on a series of linear motion trajectories. An optimal tuning problem is formulated as a nonlinear constrained optimization problem including relevant controller parameters of the servo. To verify the effectiveness of the proposed optimal tuning procedure, linear and circular motion experiments are performed on the xy-table. Experimental results confirm that both tracking and contouring errors are significantly reduced by applying the proposed control and tuning system.

• 한국항공운항학회:학술대회논문집
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• 2004.11a
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• pp.302-307
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• 2004

무인 항공기는 지상 조종 또는 자동 비행으로 원격제어, 각종 정찰, 수송, 및 공격 등의 다양한 임무를 수행할 수 있는 비행체 및 이를 포함한 시스템을 의미한다. 무인기의 자율 운항을 위해서는 위치, 속도 및 자세 등의 항법 정보를 제공하는 항법 시스템이 반드시 필요하며 크기가 작은 무인기를 위해서는 탑재체의 중량이 적은 항법 시스템이 반드시 필요하다. 최근에는 반도체 MEMS 기술을 이용한 저가형 관성 센서들이 많이 개발 되고 있으며 이를 이용한 소형, 저전력, 고정밀 항법 시스템들이 많이 연구 개발되고 있다. GPS/AHRS 결합 시스템은 자세각, 각속도, 가속도 정보 및 GPS를 이용한 위치, 슥도 정보 제공이 가능한 시스템으로 비행체의 자율비행을 위한 정보 제공이 가능한 시스템이다. 본 논문에서는 MEMS 센서를 기반으로한 GPS/AHRS 결합 항법 시스템 설계하고 차량을 이용하여 성능을 평가한 결과를 보여준다.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.291-294
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• 2006

본 연구는 화재로부터 인명과 재산을 보호하기 위한 자동 소화 시스템으로서 마이컴을 사용하여 고신뢰성, 고정밀도, DIGITAL화를 추구하는 시스템을 개발 하였다. 기존의 소화 방제 시스템들은 스프링클러를 사용하여 물로 화재를 진압하고 있으며 이러한 시스템은 비용이 많이 들고 대량의 물을 사용하고 있기 때문에 수손피해($80{\sim}120{\ell}/min$)가 있고 대용량 펌프 및 $47,000{\ell}$의 저장시설이 필요하다. 이러한 문제점을 해결하기 위하여 본 시스템은 이산화탄소($CO_2$ 가스나 하론1301 가스 또는 질소 가스를 분사하여 대기 중의 산소를 희석시키거나 질소의 양을 증가시키는 방법으로 화재를 진압하는 시스템을 개발 하였다. 개발된 시스템은 고가의 장비 즉, 전산실, 통신기기실, 전기실, 발전기실, 케이블실, 제어실, 필름 보관실 등에 사용되어 장비를 보호하고 인명의 피해를 최소화하는데 사용될 것 있다.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.12
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• pp.1379-1387
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• 2011

A PID-feedforward controller and Robust Internal-loop Compensator (RIC) based on reinforcement learning using random variable sequences are provided to auto-tune parameters for each controller in the high-precision position control of PMLSM (Permanent Magnet Linear Synchronous Motor). Experiments prove the well-tuned controller could be reduced up to one-fifth level of tracking errors before learning by reinforcement learning. The RIC compared to the PID-feedforward controller showed approximately twice the performance in reducing tracking error and disturbance rejection.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.249-255
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• 2000

The design and test of an magnetostrictive linear motor(MLM) that operates based on self-moving cell concept is presented. The moving cell is composed of Terfenol-D linear actuator and a ring structure, and a cell train is constructed by connecting two cells in series. Since this motor uses the stroke of Terfenol-D actuators and friction force of the cells, it can essentially produce long stroke and large force. The overall performance of the MLM was measured in terms of speed and force. The pushing force is directly related with the friction force. This work is a proof-of-concept stage and investigation is necessary for realistic application.