• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.157-165
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• 2000

A small hydraulic winch system with an automatic tension control unit was designed to improve the work efficiency of coastal small vessels and the dynamic response characteristics of the winch system operated in the open loop condition was investigated. The inlet and the outlet pressures in hydraulic motor, the torque and the rotating speed of winch drum were measured as a function of time, and the behaviour in autotension mode for stepped load changes was analyzed. The results obtained are summarized as follows : 1. The developed winch system for coastal small vessels will result in better fishing with improved efficiency and lower manpower consumption by remote control of winch system. 2. The rotating delay times of winch drum for on/off operations of solenoid valve were 0.09 see at CW mode and 0.04 sec at CCW mode, respectively. After the solenoid valve was controlled, response characteristics were unstable slightly but showed good tracking behaviour over short time. 3. The driving torque of winch system in autotension mode was kept almost constant of 55.9 kgf·m, and 11.1 then the rotating speed of winch drum was kept almost constant of 5.1 rpm in the larger torque than 55.9 kgf·m and 11.1 rpm in the lower torque than that. 4. The 5% settling times in the transient response characteristics of autotension mode under rapid increasing and decreasing conditions of load were 0.12 sec and 0.2 sec, respectively, and then the rotating speeds were 11 rpm and 5.3 rpm, respectively. 5. The tracking behaviour of torque and rotating speed by remote control operation were stable within 0.23 sec at CW mode and 0.37 sec at CCW mode, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3158-3163
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• 2013

In this study, squeal noise test was conducted by using the lab-scaled brake dynamometer. Squeal conditions with respect to the angle of the brake pads ($34^{\circ}30^{\circ}26^{\circ}$) and negative slope, were studied. Squeal frequency of the In-plane-like mode was confirmed by hammering test and finite element analysis. This Squeal mode was difficult to control by the pad angle variation. Also the squeal sound was found to be periodic signal which has higher harmonic components. Squeal noise is independent of the negative slope. It implies that squeal noise can reach the stick-slip oscillation.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.612-619
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• 2004

Servo motor systems with ball-screw and timing-belt are widely used in NC, robot, FA and industrial applications. However, the nonlinear friction torque and damping effect in machine elements reduce the control performance. Especially tracking errors in trajectory control and very low velocity control range are serious due to the break-away friction and Stribeck effects. In this paper, a new double speed controller is proposed for compensation of the nonlinear friction torque. The proposed double speed controller has outer speed controller and inner friction torque compensator. The proposed friction torque compensator compensates the nonlinear friction torque with actual speed and speed error information. Due to the actual information for friction torque compensator without parameters and mathematical model of motor, proposed compensator is very simple structure and the stability is very high. The proposed compensator is verified by simulation and experimental results.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.120-130
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• 1999

In this paper, we show that the instantaneous phase current of the bifiler-wound hybrid stepping motor is dependent of lead angle and that the information of motor position is obtained from the instantaneous phase current at ${\pi}/2$ by the theoretical formular and its computer simulation results. From the facts, we design the microcontroller-based motor position sensorless controller of optimal lead angle, which generates the excitation pulses for the closed-loop drives. The controller is consist of microcontroller which has the function of A/D converter, programmable input/output timer, and the transfer table which has the values of optimal lead angle depending on motor velocity, and ROM which has the transfer table of the values of lead angle depending on velocity of motor and the values of instantaneous phase current at ${\pi}/2$. From the design of microcontroller-based controller, we minimize the external interface circuit and obtain flexibility by changing the contents of ROM transfer tables and the control software. We confirm that the designed controller drives the bifilar-wound hybrid stepping motor is the mode of optimal lead angle by comparing the instananeous phase current experimental results and computer simulation results.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.5
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• pp.472-481
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• 2002

In this paper, the instantaneous flux Is applied to control the position of the SRG (Switched Reluctance Generator) without position sensor. The position information of the rotor is required in the drive of SRG. These data are generally obtained by a shaft encoder or resolver. In some cases, the EMI(Electro Magnetic Interference), vibration, thermal, and humidity environments may cause the difficulties in maintaining the satisfactory performance for the position detection. Therefore, the elimination of the position and speed sensor is needed. In this paper, a new method for the position estimation of the SRG is proposed. The estimation of the flux is calculated by using the measured voltage and current. The rotor position gets from the flux profile. The output voltage is also controlled constantly by PR control algorithm. These methods are verified by computer simulations md experiments using DSP. Experimental results certificate that the proposed method is able to control the SRG stable, and keep the output voltage constant in spite of changing of the load.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.244-245
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• 2008

본 논문은 관성센서를 이용한 무인 항공체의 자세 제어에 관한 연구를 다루었다. 항공계의 종류는 크게 고정익기와 회선익기로 나뉘는데 본 연구에서는 회전익기의 형태를 가진 Quarter Vehicle을 사통하였다. Quarter Vehicle은 4개의 프로펠러에 의한 양력과 회전 반발력으로 비행을 한다. 이때의 양력은 수평면에 대해 수직으로 추력을 발생시키므로 다른 비행체보다 불안정하며 이를 안정하게 제어하기 위해 관성 센서를 적용하여 균형을 유지한다. 본 연구에서는 관성센서를 이용하여 UAV의 자세와 균형을 안정적으로 유지하여 안정적인 비행이 가능하도록 하였다. 또한 상호 의존적인 항법 시스템으로 환경변화에 영향을 받지 않으며, 정확한 위치정보를 제공하는 GPS를 사용하여 3개 이상의 위성으로부터 정보를 받아 좌표를 계산하고 위치, 속도 및 방향을 결정하여 자율 비행이 가능하도록 설계하였다. 본 논문에서는 Quarter Vehicle의 구조와 이론적 배경을 통한 설계, 그리고 관성센서와 GPS의 적용을 위한 방법을 제시 한다.

• Journal of Astronomy and Space Sciences
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• v.8 no.1
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• pp.85-98
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• 1991

Geomagnetism was used to control the attitude of the small scientific satellite at low altitude in sun-synchronous orbit. First, we analyzed the telemetry data. The rotation state of the satellite, can be known from the magnitude and variations of the magnetic field which is measured from the 3 axis magnetometer. In axisymmetric case, it is possible to control the attitude of the satellite by changing the rotation velocity of each 3 axis. The algorithm and the program were developed to calculate the supply time of the current operating the magnetorquer. This attitude control can be applied when the satellite is in tumbling motion and after passive control is attained by the Gravity gradient boom.

• JOURNAL OF ELECTRICAL WORLD
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• s.290
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• pp.90-94
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• 2001

일본의 수력발전소는 국산에너지의 주력산업으로 클린하며 또한 재생 가능한 에너지로서 수백kW의 소수력에서 500MVA급의 대용량 양수까지, 여러 목적에 맞는 역할을 다하고 있다. 특히 양수발전소는 전력계통의 부하 평활화라는 중책을 담당하고 있으며, 앞으로 전력수요의 증가에 따라 더욱더 그 중요도는 증가할 것이다. 미쓰비시전기의 양수발전소의 단위용량은 1990년대 전반까지는 367MVA(도쿄전력 신고뢰천)가 최대였으나 ''98년 운전 개시한 간사이 전력 오다다양목의 400MVA, 2000년 운전 개시한 국내최대용량의 도쿄전력 갈야천의 475MVA로 최근 대용량화가 진전되어 그 대용량기술의 진보는 크게 주목을 받고 있다. 또 주기의 회전속도에 있어서도 400min${^-1}$급에서 500min${^-1}$로, ''보다 더 고속대용량화'' 시대에 돌입하였다고 할 수 있다. 또한 수력발전소는 일찍부터 일인화$\cdot$무인화에 의한 감시제어의 자동화$\cdot$성력화가 추진되어 왔다. ''50년대의 일인화제어를 거쳐'' 60년대에는 원방감시제어화에 의해 완전자동화$\cdot$무인화를 실현하였다. 그 후에도 디지털기기의 응용에 의하여 감시제어장치의 고기능화가 진전되고 또 보호도 포함한 토털디지털시스템도 구축되어 있다. 또한 중소수력발전소에 대하여는 종래 분산시스템이었던 시퀀서/거버너/AVR을 1CPU로 실현한 일체형배전반이 차후의 중소 수력제어장치의 주력기종이 되고 특히 범용컨트롤러를 적용한 시스템도 실용화되어 가고 있다. 본고에서는 최근의 수차, 발전기의 고속$\cdot$대용량화를 중심으로 한 동향과 감시제어시스템의 기술동향을 소개함과 동시에 앞으로의 전망에 대하여 기술하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.239-246
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• 2003

Brushless D.C. Motor is widely used for industrial application because of high efficiency and high power density. Especially, in home appliance, BLDCM is very useful due to high control performance and low acoustic noise. In this paper, BLDCM and its controller are designed and developed for tread mill application. With the restricted stator structure, permanent magnet rotor is designed for manufacturing and cost effectiveness using CAD and FEM analysis. A ferrite magnetic material is used as a rotor magnet for the cost and temperature advantages. For a stable operation of tread mill, over current and temperature can be detected and protected. The designed BLDCM and its controller was verified by the experimental results.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.538-539
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• 2010

자기 베어링 시스템은 축과 베어링간의 자기적 힘을 이용하여 축을 비접촉으로 지지함으로써 고속으로 회전하는 회전체의 마찰손을 저감시킨다. 고속 회전체에 편심(Eccentricity)이 있을 경우 편심 질량으로 인한 원심력이 속도의 제곱에 비례하여 발생하게 되고, 축을 지지하고 있는 베어링에 과도한 진동을 유발하게 된다. 베어링에 전해지는 진동이 커지게 되면 진동 자체도 문제일 뿐 아니라 베어링이 부담해야 하는 힘의 크기가 커지게 되어 자기 베어링 및 이를 구동하는 전력전자 기기의 용량을 증가시켜야 하는 문제가 있다. 본 논문에서는 베어링의 지지력을 능동적으로 제어하는 능동 자기 베어링을 사용하여 축의 편심 질량의 크기 및 편심 위치를 파악하고 회전 관성 중심점으로 축을 회전시킴으로써 회전 진동을 저감하는 방법을 제안하고, 실험 결과로써 제안된 방법의 타당성을 검증한다.