• Journal of KIEE
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• 제10권1호
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• pp.16-22
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• 2000

The Main role of the gas turbine lies in the utilization of waste heat which may be found in exhaust gases from the gas turbine or at some other points of the process to produce additional electricity. Up to date, the PID controller has been used to operate under such difficult conditions, but since the gain of PID controller manually experience. In this paper parameter separation type 2-DOF PID controllers are proposed based on the gas turbine control system. Gas turbine transfer function is achieved from operation data of Gun-san gas turbine and Tuning algorithms of parameter separation type 2-DOF PID controller is ANFIS. Results represents satisfactory response.

• 대한기계학회논문집A
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• 제37권6호
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• pp.805-814
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• 2013

유압식 Dipod 플랫폼은 기동차량에서 위성을 지향하는 안테나의 안정화 및 추적에 사용된다. 이러한 플랜트의 제어기 설계에는 외란제거와 추적 두 가지 성능목표 뿐만 아니라 강인성을 함께 절충해야 하는 제약조건으로 인해 1자유도 제어기에 비해 설계 유연성이 큰 2자유도 $H_{\infty}$ 제어기가 선호된다. $H_{\infty}$ 기반한 2자유도 제어기 종합방법에는 두 가지 프레임웍이 사용되는데 유압식 Dipod 플랫폼의 예를 통해서 일괄종합 방법이 더 우수한 성능을 보인 반면 분리종합 방법은 더 우수한 강인성을 보임을 확인할 수 있었다. $H_{\infty}$ 2자유도 종합방법에 따른 이러한 두 결과의 차이를 시스템 정합행렬의 구조화 특성을 통해 비교하여 보았다.

• 한국음향학회지
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• 제20권2호
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• pp.58-65
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• 2001

잔향에 대한 인간의 주관적인 지각을 객관적인 수치로써 나타내는 방법으로 5자유도 잔향 모델이 제안된 바 있다[1]. 5자유도 잔향 모델은 잔향에 대한 다섯 개의 객관적인 평가량들을 이용하여 시간에 따른 음 에너지 감쇠 곡선을 근사한 것으로, 인공적으로 잔향을 합성하고자 할 때 잔향 필터의 설계 기준으로 유용하게 사용될 수 있다. 그러나 이로부터 구현할 수 있는 잔향 필터는 이론적으로 무한히 많을 수 있고, 따라서 인간이 듣기에 부자연스러운 합성음을 만들어 내는 경우도 존재할 수 있다. 본 논문은 5자유도 잔향 모델의 한계를 시간 영역과 주파수 영역으로 나누어 살펴보고 잔향 모델, 즉 원하는 잔향 조건이 주어졌을 때 자연스러운 잔향을 얻기 위해 필요한 필터 설계 기준을 실제 청음 실험을 통하여 제시하고 있다.

• 한국광학회지
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• 제12권3호
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• pp.190-199
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• 2001

본 연구에서는 193nm의 ArF excimer laser 광원과 0.65의 NA를 갖는 광학계에서 기본 선폭이 $0.1{\mu}m$이고 duty ratio 가 1:1인 dense line & space(LS) 패턴에 대하여 여러사입사 조명 조건에 따른 초점심도(Depth of Focus; DOF)와 cutoff intensity를 확인하고 기본 capacitor 패턴에서 광학적 근접효과 보정을 위한 hammer head형 보조 패턴의 크기와 여러사입사 조건에 다른 DOF와 cutoff intensity의 변화에 대하여 알아보았다. 그결과 0.1$\mu$m급의 dense 패턴 구현을 위해서는 전형적인 X자형 사구 조명보다는 십자(+)형 사구 조명이나 환형조명이 보다 효과적인 것을 알수 있었다. 이와 더불어 보조 패턴의 크기가 약간 변한다 하더라도 일정한 초점심도와 cutoff intensity를 유지하는 경향을 보이는 특정한 조명 조건이 존재함을 밝히고 그에 따라 최적의 조명 조건과 보조 패턴의 크기에 대하여 알아보았다.

• 로봇학회논문지
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• 제8권1호
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• pp.8-19
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• 2013

One of the important issues for structural and electrical specifications in developing a robot is to determine lengths of links and motor specifications, which need to be appropriate to the purpose of robot. These issues become more critical for a gait rehabilitation robot, since a patient wears the robot. Prior to developing an entire gait rehabilitation robot, designing of a 1DOF assistive knee joint of the robot is considered in this paper. Human gait motions were used to determine an allowable range of knee joint that was rotated with a linear type actuator (ball-screw type) and links. The lengths of each link were determined by using an optimization process, minimizing the stroke of actuator and the total energy (kinetic and potential energy). Kinetic analysis was performed in order to determine maximum rotational speed and maximum torque of the motor for tracking gait trajectory properly. The prototype of 1 DOF assistive knee joint was built and examined with a impedance controller.

• Journal of Power Electronics
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• 제4권1호
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• pp.28-38
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• 2004

In this paper, the position control of a detuned indirect field oriented control (IFOC) induction motor drive is studied. A proposed Simple-Neuro-Controllers (SNCs) are designed and analyzed to achieve high-dynamic performance both in the position command tracking and load regulation characteristics for robotic applications. The proposed SNCs are trained on-line based on the back propagation algorithm with a modified error function. Four SNCs are developed for position, speed and ｄ-ｑ axes stator currents respectively. Also, a synchronous proportional plus integral-derivative (PI-D) two-degree-of-freedom (2DOF) position controller and PI-D speed controller are designed for an ideal IFOC induction motor drive with the desired dynamic response. The performance of the proposed SNCs and synchronous PI-D 2DOF position controllers for detuned field oriented induction motor servo drive is investigated. Simulation results show that the proposed SNCs controllers provide high-performance dynamic characteristics which are robust with regard to motor parameter variations and external load disturbance. Furthermore, comparing the SNC position controller with the synchronous PI-D 2DOF position controller demonstrates the superiority of the proposed SNCs controllers due to attain a robust control performance for IFOC induction motor servo drive system.

• Journal of Communications and Networks
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• 제16권1호
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• pp.18-25
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• 2014

In this paper, we propose a codebook-based interference alignment (IA) scheme in the constant multiple-input multiple-output (MIMO) interference channel especially for the uplink scenario. In our proposed scheme, we assume cooperation among base stations (BSs) through reliable backhaul links so that global channel knowledge is available for all BSs, which enables BS to compute he transmit precoder and inform its quantized index to the associated user via limited rate feedback link. We present an upper bound on the rate loss of the proposed scheme and derive the scaling law of the feedback load to maintain a constant rate loss relative to IA with perfect channel knowledge. Considering the impact of overhead due to training, cooperation, and feedback, we address the effective degrees of freedom (DOF) of the proposed scheme and derive the maximization of the effective DOF. From simulation results, we verify our analysis on the scaling law to preserve the multiplexing gain and confirm that the proposed scheme is more effective than the conventional IA scheme in terms of the effective DOF.

• Journal of Mechanical Science and Technology
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• 제17권9호
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• pp.1268-1275
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• 2003

In this paper, a compact 3-DOF mobile microrobot with sub-micron resolution is presented. It has many outstanding features : it is as small as a coin ; its precision is of sub-micrometer resolution on the plane ; it has an unlimited travel range ; and it has simple and compact mechanisms and structures which can be realized at low cost. With the impact actuating mechanism, this system enable both fast coarse motion and highly precise fine motion with a pulse wave input voltage controlled. The 1 -DOF impact actuating mechanism is modeled by taking into consideration the friction between the piezoelectric actuator and base. This modeling technique is extended to simulate the motion of the 3-DOF mobile robot. In addition, experiments are conducted to verify that the simulations accurately represent the real system. The modeling and simulation results will be used to design the model-based controller for the target system. The developed system can be used as a robotic positioning device in the micromanipulation system that determines the position of micro-sized components or particles in a small space, or assemble them in the meso-scale structure.

• 한국해양공학회지
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• 제36권1호
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• pp.50-60
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• 2022

The deep ocean engineering basin (DOEB) of the Korea Research Institute of Ship and Ocean Engineering (KRISO) is equipped with an extreme-environment reproduction facility that can analyze the motion characteristics of offshore structures and ships. In recent years, there have been requirements for a wide range of six-degree-of-freedom (6-DOF) motion measurements for performing maneuvering tests and free-running tests of target objects (offshore structures or ships). This study introduces the process of developing a wide-area motion measurement technology by incorporating the auto-tracking technology of the towing carriage system to overcome the existing 6-DOF motion measurement limitation. To realize a wide range of motion measurements, the automatic tracking control system of the towing carriage in the DOEB was designed as a speed control method. To verify the control performance, the characteristics of the towing carriage according to the variation in control gain were analyzed. Finally, a wide range of motions was tested using a model test object (a remotely operated vehicle (ROV)), and the wide-area motion measurement technology was implemented using an automatic tracking control system for a towing carriage.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.853-859
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• 2015

진동대 실험 시 진동대와 구조물 사이에 발생하는 상호작용을 파악하기 위하여 1자유도 전단건물의 조화진동 실험을 전자기력으로 구동되는 힘-제어 진동대를 이용하여 수행하였다. 실험에서는 진동대와 전단건물의 수평방향 가속도를 측정하였으며, 실험 결과를 이해하기 위한 방법으로 전단건물의 진동대 실험을 조화하중이 작용하는 비구속 2자유도계로 이상화하였다. 이상화 된 이론모델의 운동방정식으로부터 전단건물과 진동대의 가속도를 구하였으며, 이들 가속도를 가진력에 대한 비로 나타낸 증폭계수와 진동대의 가속도 진폭에 대한 전단건물의 가속도 진폭의 비인 전달계수를 구하였으며, 이들 결과를 실험결과와 비교하여 진동대와 전단건물 사이에 발생하는 상호작용을 파악하였다.