모멘트쌍 액추에이터가 적용된 PPF에 의한 평판의 능동진동제어

신창주(Shin, Chang-Joo),홍진숙(Hong, Chin-Suk),정의봉(Jeong, Weui-Bong),유호영(You, Ho-Young) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.4

This paper reports the active vibration control of plates using a positive position feedback(PPF) controller with moment pair actuators. The equations of motion of the plates under a force and moment pairs are derived and the equations of PPF controllers are formulated. The numerical active control system is then achieved. The effect of the parameters - gain and damping ratio - of the PPF controllers on the open loop transfer function was investigated mainly in terms of the system stability. Increasing the gain of the PPF controller tuned at a mode, the magnitude of the open loop transfer function is increased at all frequencies without changing the phase behavior. The increase of the damping ratio of the PPF controller leads to decrease the magnitude of the open loop transfer function and to modify its phase characteristics, ie, system stability. Based on the behavior of the gain and the damping ratio of the controller, PPF controller for reduction of the plate vibration can be achieved. Two PPF controllers are designed with their connection in parallel to control the two modes simultaneously. Each PPF controller is tuned at the $1^{st}$ and $2^{nd}$ modes, respectively. Their parameters were determined to remain the system to be stable based on the results of the parametric study. A significant reduction in vibration at the tuned modes can be obtained.

Filtered Velocity Feedback 제어기를 이용한 양단지지보의 음향파워 저감

신창주(Shin, Chang-Joo),홍진숙(Hong, Chin-Suk),정의봉(Jeong, Weui-Bong) 한국소음진동공학회 2011 한국소음진동공학회 논문집 Vol.21 No.12

This paper investigates the filtered velocity feedback(FVF) controller for the reduction of the acoustic power radiated from a clamped beam. The instability problem due to the non-collocated sensor/actuator configuration when using PZT actuator should be sorted out. The roll-off property of the FVF controller at high frequency helps to alleviate the instability. The dynamics of clamped beams under forces and moments pair and the FVF controller are first formulated. The formulation of the sound radiated power is followed. The open loop transfer function(OLTF) synthesized with 100 modes is used to determine the stability of the control system. The control performance is finally estimated. The levels of the vibration and the sound radiated power are reduced in the wide bandbelow the tuning mode of the FVF controller.

주기대칭법을 이용한 원통형 배열 구조물의 접수진동 해석

신창주(Chang Joo Shin),홍진숙(Chinsuk Hong),정의봉(Weui Bong Jeong),서희선(Hee Seon Seo) 한국소음진동공학회 2007 한국소음진동공학회 학술대회논문집 Vol.2007 No.11

PZT Actuator를 이용한 외팔보의 능동진동제어

신창주(Shin, Chang-Joo),홍진숙(Hong, Chin-Suk),정의봉(Jeong, Weui-Bong) 한국소음진동공학회 2008 한국소음진동공학회 논문집 Vol.18 No.12

This paper presents an active vibration control of cantilever beams under disturbances by a primary force. A direct velocity feedback control using a pair of PZT actuator and a velocity sensor is considered. Variation of the stability and performance with the locations of the sensor/actuator pair is investigated. It is found that the maximum gain varies with the locations of the sensor/actuator pair significantly. The maximum gain shows a symmetric distribution along the beam length with respect to the center point, although the boundary condition of the beam is unsymmetric. The control performance is affected by the location of the primary force as well as the location of the sensor/actuator pair. The active control system can more effectively reduce the vibration when the primary force is located close to the fixed boundary.

Filtered Velocity Feedback 제어기를 이용한 양단지지보의 능동진동제어

신창주(Shin, Chang-Joo),홍진숙(Hong, Chin-Suk),정의봉(Jeong, Weui-Bong) 한국소음진동공학회 2011 한국소음진동공학회 논문집 Vol.21 No.5

This paper reports a filtered velocity feedback(FVF) controller, which is an alternative to direct velocity feedback(DVFB) controller. The instability problems due to high frequency response under DVFB can be alleviated by the suggested FVF controller. The FVF controller is designed to filter out the unstable high frequency response. The FVF controller and the dynamics of clamped beams under forces and moments are first formulated. The effects of the design parameters(cut-off frequency, gain, and damping ratio) on the stability and the performance are then investigated. The cut-off frequency should be selected not to affect the system stability. The magnitude of the open loop transfer function(OLTF) at the cut-off frequency should be small. As increasing the gain of the FVF controller, the magnitude of the OLTF is increased, so that the closed loop response can be reduced more. The enhancement of the OLTF at the cut-off frequency is reduced but the phase behavior around the cut-off frequency is distorted, as the damping ratio is increased. The control performance is finally estimated for the clamped beam. More than 10 dB reductions in velocity response can be achieved at the modal frequencies from the first to eighth modes.

가속도 되먹임 제어기를 이용한 양단지지보의 능동 제어

신창주(Shin, Chang-Joo),홍진숙(Hong, Chin-Suk),정의봉(Jeong, Weui-Bong),정상우(Jeong, Sang-Woo) 한국소음진동공학회 2010 한국소음진동공학회 논문집 Vol.20 No.12

This paper reports active control of clamped beams using acceleration feedback controllers (AF). The equations of motion of clamped beam under force and moment pairs were derived and the equations of AF controllers were formulated. The effect of the parameters - gain and damping ratio - of the AF controllers on the open loop transfer function was investigated mainly in terms of the system stability. Increasing the gain of the AF controller tuned at a mode, the magnitude of the open loop transfer function is increased at all frequencies. The increase of the damping ratio of the AF controller leads to decrease the magnitude of the open loop transfer function and modifies its phase characteristics to be more stable. Three AF controllers connected in parallel were then proposed. Each AF controller is tuned at the 2nd, 3rd and 4th modes, respectively. Their parameters were determined to remain the system to be stable based on the results of the parametric study. A significant reduction in vibration at the 3 modes can be obtained.

선체부착형 원통형 배열 소나의 선체충격에 의한 응답

신창주(Shin, Chang-Joo),홍진숙(Hong, Chin-Suk),정의봉(Jeong, Weui-Bong),서희선(Seo, Hee-Seon) 한국소음진동공학회 2009 한국소음진동공학회 논문집 Vol.19 No.2

Dynamic response of a hull mounted sonar(HMS) to shocks transmitted through hull structures is analyzed and then the structural reliability of the sonars is evaluated. Finite element model of the hull mounted sonar is established and the transient responses to the shock is calculated using MSC.NASTRAN. According to BV043, the maximum allowable accelerations at the foundation of the sonar are converted from the shock spectra allowable for HMS. They are applied vertically and horizontally, respectively, using the large mass method. The structural reliability is evaluated by comparing the von-Mises stresses with the material yield stress. The drum for sensors shows a high reliability owing to mounts by which the shock waves from the base structure are well protected. However, the mounts between the base structure and the drum to mount sensors show a high stress intensity. The base structure also reveals a high stress intensity at the connection points to the hull.

Filtered Velocity Feedback 제어기를 이용한 평판 능동진동제어

신창주(Shin, Chang-Joo),홍진숙(Hong, Chin-Suk),정의봉(Jeong, Weui-Bong) 한국소음진동공학회 2011 한국소음진동공학회 논문집 Vol.21 No.10

This paper reports a filtered velocity feedback(FVF) controller, which is an alternative to direct velocity feedback(DVFB) controller. The instability problems at high frequencies due to non-collocated sensor/actuator configuration with the DVFB can be alleviated by the proposed FVF controller. The FVF controller is designed to filter out the unstable high frequency response. The dynamics of a clamped plate under forces and moments and the FVF controllers are formulated. The stability of the control system and performance are investigated with the open loop transfer function(OLTF). It is found that the FVF controller has a higher gain margin than the corresponding DVFB controller owing to the rapid roll-off behavior at high frequencies. Although the gain margin cannot be fully utilized because of the enhancement at the high frequencies, the vibration at the modes lower than the tuning frequency is well controlled. This performance of the FVF controller is shown to be improved from that of the DVFB controller. It is, however, noted that the stability around the tuning frequency is very sensitive so that the enhancement in vibration level should be followed. The reduction performance at low frequencies using the FVF controller should be compromised with the enhancement in the vibration at high frequencies while designing the controller.

탁도가 높은 수중작업현장에 사용 가능한 소나시스템의 성능 분석

신창주(Shin, Changjoo),장인성(Chang, In-Soung),김기훈(Kim, Ki-Hoon),최현택(Choi, Hyun-Tack),이승현(Lee Seung-Hyun) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.9

수중사석고르기와 같은 수중공사작업을 수행하기 위하여 개발 진행 중인 무인수중장비를 수중공사현장에 투 입할 경우, 작업 시 발행하는 부유물들로 인하여 탁도가 높아진다. 이러한 수중환경에서 광학카메라를 이용할 경우, 수중전방인식이 불가능할 수 있다. 이를 극복하기 위하여 무인수중장비에 소나를 탑재하고자 한다. 소나를 무인수중 장비에 적용하기에 앞서, 본 연구에서는 소나의 분해능, 탁도가 높은 물 속에서 스캐닝한 소나이미지를 확인하여 장 비의 성능을 분석하였다. 그리고 수중공사현장의 경계면을 표시하기 위한 방법을 제안하였다. 이를 통하여 무인수중 장비에 적용하기 위한 소나의 기초 성능을 확인하였다. The developing unmanned underwater equipment can be used for underwater construction site such as underwater leveling works. If a optical camera is applied to the unmanned underwater equipment, recognition in underwater can be gone to low due to high turbidity in working field. To overcome this problem, a sonar will be installed to the unmanned underwater equipment. In this study, the resolution of the sonar and the quality test of the sonar image under high turbidity environment were conducted. And the method to indicate the boundary of the underwater construction site was proposed. By these results, the basic performance of the sonar was evaluated.

위치인식 신호획득 주기변화에 의한 위치추정값 영향

신창주(Changjoo Shin),권오순(Osoon Kwon),서정민(Seo Jungmin),강현(Hyoun Kang) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.3

한국해양과학기술원은 해저에서 지면 굴착 작업이 가능한 트랙 형태의 수중건설로봇 (URI-R)을 개발 중에 있다. 개발 로봇은 수중에서 굴착 작업을 수행하는 동안 강한 소음 및 진동 환경에 노출된다. 이로 인하여 음향을 이용하여 수중 위치 신호를 획득하여야 하는 개발 장비는 신호획득이 어려운 상황에 빈번하게 놓일 수 있다. 이를 극복하기 위하여 개발 장비가 수중 위치 신호가 간헐적으로 들어오는 상황 속에 놓여 있어도 연속적으로 자신의 위치를 인식하는 방안을 확보하는 것이 필요하다. 본 논문에서는 비용절감 및 다양한 실험케이스를 확보하기 위하여 수중 작동 특성을 모사할 수 있는 실험을 육상에서 재현하여 실험하였으며 위치 추정을 위하여 관성항법 및 위성항법신호를 사용하였다. 위치 신호획득 주기가 길어짐에 따라 자기 위치 추정에 미치는영향을 실험적으로 고찰하였다. 이를 통하여 URI-R의 연속적인 자기 위치 인식을 수행하기 위한 위치 신호획득의 최대 주기를 확인하고 이를 적용하고자 한다. A track type underwater construction robot(URI-R) which can trench on seabed is being developed by Korea Institute of Ocean Science & Technology. During the underwater trenching work, the robot is exposed high intensive noise and vibration so the underwater localization signal may not be obtained properly by the acoustic tracking system. Therefore it is necessary to research about continuous localization even though the measured position signal comes in intermittently. In this paper, the experiments were carried out on land to simulated the underwater operating environment characteristics. To estimate its position, inertial navigation system and global navigation satellite system are used. The effects of the period variation while localizing is investigated by the experiments, and the application for URI-R is proposed.