• Title, Summary, Keyword: vibration control device

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New vibration control device and analytical method for slender structures

  • Takabatake, Hideo;Ikarashi, Fumiya
    • Earthquakes and Structures
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    • v.4 no.1
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    • pp.11-39
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    • 2013
  • Since slender structures such as utility poles, radio masts, and chimneys, are essentially statically determinate structures, they often collapse during earthquakes. Although vibration control is the most logical method for improving the earthquake resistance of such structures, there are many practical problems with its implementation due to their very long natural vibration period. This paper proposes a new vibration control device to effectively prevent the collapse of slender structures subjected to strong earthquakes. The device consists of a pendulum, an elastic restraint and a lever, and is designed such that when it is attached to a slender structure, the second vibration mode of the structure corresponds to the first vibration mode of the same structure without the device attached. This is highly effective in causing the transverse motions of the device and the structure to oppose each other and so reduce the overall transverse vibration during an earthquake. In the present paper, the effectiveness of the vibration control device is first evaluated based on laboratory experiments and numerical studies. An example of applying the device to a tall chimney is then simulated. A new dynamic analytical method for slender structures with abrupt rigidity variations is then proposed.

Vibration Control of a Structure Using the Toggle-Rotational Inertia Damper (토글-회전관성댐퍼를 이용한 구조물의 진동제어)

  • Hwang, Jae-Seung;Choi, Rak-Sun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.586-590
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    • 2006
  • This paper presents a new vibration control device by which the mass and damping of a structure is increased equivalently. The vibration control system, named toggle-rotational inertia-viscous damper, can be utilized effectively in applications of small structural drift. Numerical analysis shows that because the relative drift of a structure can be effectively amplified by the toggle system, the device has a great performance in the vibration control without the increase of the damper capacity and size. It is also observed that vibration control effects is caused by the increase of equivalent mass and damping due to the rotational inertia and damping of the device.

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A Method to Prevent Transfer Device of Image Stabilizer from Blunting by Artificial Vibration (가진입력에 의한 손떨림 보정용 이송장치의 둔화현상 방지대책)

  • Yeom, Dong-Hae
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.11
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    • pp.1076-1079
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    • 2009
  • This article deals with an optical image stabilizer which moves an image sensor in the direction of cancelling the vibration caused by hand shaking to prevent a photographed image from blurring. The ball-guide way method adopted as a transfer device of the image sensor is easy to be manufactured because of its simple structure and is suitable to minimize the friction between mechanisms, but has weakness of a chance of physical defect such as groove and rising. In case that the movement of the transfer device equipped with the image sensor is blunted because a ball is stuck in defects of guide way, the performance of the image stabilizer falls down drastically. We propose a method to prevent the transfer device from blunting by applying artificial vibration. At this time, the artificial vibration should be designed under consideration of dynamic characteristics and specifications of the system to be discriminated from the vibration caused by hand shaking.

Active Control of Air-Spring Vibration Isolator (공기스프링 방진대의 능동제어)

  • 송진호;김규용;박영필
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.7
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    • pp.1605-1617
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    • 1994
  • Air-spring is widely used in vibration isolation to reduce the table vibration. When a disturbance is applied to a table, however, it starts virbrating with a low frequency, but has a large displacement due to the reacting force of air-spring. In this study, to solve the table vibration problem, an active vibration control device based on state feedback control using air-spring and proportional control valves was designed. This device can suppress the displacement of the isolation table within allowable range, even any kind of disturbances are applied to the table. Firstly, theoretical analysis of an air-spring isolator was done. Secondly, characteristics of the isolator was investigated via computer simulation and experiment. Finally, active control of air-spring isolator was tested using optimal(LQG) and fuzzy control algorithms was performed to show the effectiveness of the control schems.

Obstacle Information Transfer and Control Method using Haptic Device consist of Vibration Motors (진동모터로 구성된 햅틱 디바이스를 이용한 장애물 정보 전달 및 제어 방법)

  • Lee, Dong-Hyuk;Noh, Kyung-Wook;Kang, Sun Kyun;Han, Jong Ho;Lee, Jang-Myung
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.10
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    • pp.1036-1043
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    • 2014
  • In this paper, a new haptic device is proposed for the teleoperation, which can recognize the invisible environment of a mobile robot. With this new device, it is possible for the user to identify the location of an obstacle and to avoid it. The haptic device has been attached on the top of a joystick so that the user can remotely control the mobile robot to avoid the obstacles which are recognized by the ultrasonic sensors. Also, the invisible environment is recognized more accurately overlapping the data from the ultrasonic sensors. There are five vibration motors in the haptic device to indicate the direction of the obstacle. So the direction of the obstacle can be recognized by the vibration at the finger on each vibration motor. For various situations and surrounding environments, experiments are performed using fuzzy controller and overlapping ultrasonic sensors. The results demonstrate the effectiveness of the proposed haptic joystick.

Design of Magneto-rheological Fluid Based Device (자기유변유체를 이용한 공학 장치의 설계)

  • Kim, Jeong-Hoon;Lee, Chong-Won;Jung, Byung-Bo;Park, Young-Jin;Cao, Guangzhong
    • Proceedings of the KSME Conference
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    • pp.544-549
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    • 2001
  • The effect of power supply voltage on the performance limits in a laboratory Magneto-rheological fluid based device was identified by experiments. It suggests that the frequency range of motion for control be limited by the voltage attenuation due to the coil inductance and the maximum power supply voltage set for practical use of MRF devices. In this work, the magnetic and electrical characteristics of MRF device are investigated and a design procedure is formulated to achieve the desired performance for a given power supply.

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Study for the Vertical Vibratioin Control Method of Railway Structure (철도구조물의 연직진동 제어기법에 관한 연구)

  • Choi, Eun-Soo;Lee, Joo-Tak;Yu, Seong-Mun;Lee, You-In
    • Proceedings of the KSR Conference
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    • pp.1242-1247
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    • 2011
  • This study investigates vertical vibration control method for railway structure by using vertical vibration control device. The device consists of high stiffness polyurethane spring and friction damper recognized by National Center for Earthquake Engineering Research of USA for durability. To confirm the capacity of vertical vibration control, at first, behavior equation is established by considering correlation among the components. Then, hysteresis curve is drawed from behavior equation. By considering both dynamic behaviors and material nonlinearities, more reasonable behavior of the device can be simulated. After that, the Validity of the vibration control trend is proved by FEM(Finite Element Method).

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Design and Control of Haptic Cue Device for Accelerator Pedal Using MR Brake (MR 브레이크를 이용한 햅틱 큐 가속페달 장치 설계 및 제어)

  • Noh, Kyung-Wook;Han, Young-Min;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.5
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    • pp.516-522
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    • 2009
  • This paper proposes a new haptic cue vehicle accelerator pedal device using magnetorheological(MR) brake. As a first step, an MR fluid-based haptic cue device is devised to be capable of rotary motion of accelerator pedal. Under consideration of spatial limitation, design parameters are optimally determined to maximize control torque using finite element method. The proposed haptic cue device is then manufactured and integrated with accelerator pedal. Its field-dependant torque is experimentally evaluated. Vehicle system emulating gear shifting and engine speed is constructed in virtual environment and communicated with the haptic cue device. Haptic cue algorithm using the feed-forward control algorithm is formulated to achieve optimal gear shifting in driving. Control performances are experimentally evaluated via feed-forward control strategy and presented in time domain.

Design and Control of Haptic Cue Device for Accelerator Pedal Using MR Brake (MR 브레이크를 이용한 햅틱 큐 가속페달 장치 설계 및 제어)

  • Noh, Kyung-Wook;Han, Young-Min;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.627-632
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    • 2009
  • This paper proposes a new haptic cue vehicle accelerator pedal device using magnetorheological (MR) brake. As a first step, an MR fluid-based haptic cue device is devised to be capable of rotary motion of accelerator pedal. Under consideration of spatial limitation, design parameters are optimally determined to maximize control torque using finite element method. The proposed haptic cue device is then manufactured and integrated with accelerator pedal. Its field-dependant torque is experimentally evaluated. Vehicle system emulating gear shifting and engine speed is constructed in virtual environment and communicated with the haptic cue device. Haptic cue algorithm using the feed-forward control algorithm is formulated to achieve optimal gear shifting in driving. Control performances are experimentally evaluated via feed-forward control strategy and presented in time domain.

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Study on Process Monitoring of Elliptical Vibration Cutting by Utilizing Internal Data in Ultrasonic Elliptical Vibration Device

  • Jung, Hongjin;Hayasaka, Takehiro;Shamoto, Eiji
    • International Journal of Precision Engineering and Manufacturing-Green Technology
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    • v.5 no.5
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    • pp.571-581
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    • 2018
  • In the present study, monitoring of elliptical vibration cutting process by utilizing internal data in the ultrasonic elliptical vibration device without external sensors such as a dynamometer and displacement sensor is investigated. The internal data utilized here is the change of excitation frequency, i.e. resonant frequency of the device, voltages applied to the piezoelectric actuators composing the device, and electric currents flowing through the actuators. These internal data change automatically in the elliptical vibration control system in order to keep a constant elliptical vibration against the change of the cutting process. Correlativity between the process and the internal data is described by using a vibration model of ultrasonic elliptical vibration cutting and verified by several experiments, i.e. planing and mirror surface finishing of hardened die steel carried out with single crystalline diamond tools. As a result, it is proved that it is possible to estimate the elements of elliptical vibration cutting process, e.g. tool wear and machining load, which are important for stable cutting in such precision machining.