• Title, Summary, Keyword: Vibration Control

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Study on Satellite Vibration Control Using Adaptive Algorithm

  • Oh, Choong-Seok;Oh, Se-Boung;Bang, Hyo-Choong
    • 제어로봇시스템학회:학술대회논문집
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    • pp.2120-2125
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    • 2005
  • The principal idea of vibration isolation is to filter out the response of the system over the corner frequency. The isolation objectives are to transmit the attitude control torque within the bandwidth of the attitude control system and to filter all the high frequency components coming from vibration equipment above the bandwidth. However, when a reaction wheels or control momentum gyros control spacecraft attitude, vibration inevitably occurs and degrades the performance of sensitive devices. Therefore, vibration should be controlled or isolated for missions such as Earth observing, broadcasting and telecommunication between antenna and ground stations. For space applications, technicians designing controller have to consider a periodic vibration and disturbance to ensure system performance and robustness completing various missions. In general, past research isolating vibration commonly used 6 degree order freedom isolators such as Stewart and Mallock platforms. In this study, the vibration isolation device has 3 degree order freedom, one translational and two rotational motions. The origin of the coordinate is located at the center-of-gravity of the upper plane. In this paper, adaptive notch filter finds the disturbance frequency and the reference signal in filtered-x least mean square is generated by the notch frequency. The design parameters of the notch filter are updated continuously using recursive least square algorithm. Therefore, the adaptive filtered-x least mean square algorithm is applied to the vibration suppressing experiment without reference sensor. This paper shows the experimental results of an active vibration control using an adaptive filtered-x least mean squares algorithm.

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A Design of Active Vibration Control System Using Electromagnetic Actuators (전자기 액츄에이터를 이용한 진동제어시스템)

  • Lee, Joo-Hoon;Jeon, Jeong-Woo;Caraiani, Mitica;Kang, Dong-Sik
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.936-939
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    • 2006
  • The pneumatic isolator is widely adopted for anti-vibration of precision measuring and manufacturing equipments. But, when the precision demand on anti-vibration is extreme or the load is moving, the performance of anti-vibration can not meet satisfaction. In these cases, as a complementary, active vibration suppression system can be added for advanced performance. In this paper, an active control system is presented, which uses electromagnetic actuators for vibration suppression. The anti-vibration characteristic of pneumatic isolator is analyzed for system modeling and actuator specifying. The modeling and the 3D dynamic simulation is performed for control system design. For the electromagnetic actuator design, the magnetic flex density and the current-force characteristic analysis are achieved.

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Transverse Vibration Control of an Axially Moving String by Velocity Boundary Control (속도경계제어를 이용한 축방향 주행 현의 횡진동 제어)

  • Ryu, Du-Hyeon;Park, Yeong-Pil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.1
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    • pp.135-144
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    • 2001
  • In this study, the time varying boundary control using the right boundary transverse motion is suggested to stabilize the transverse vibration of an axially moving string on the basis of the energy flux between the moving string and the boundaries. The effectiveness of the active velocity boundary control is showed through the FDM simulation results. Sliding mode control is adopted in order to achieve velocity tracking control of the time varying right boundary to dissipate vibration energy of the string effectively. Optical sensor system for measuring the transverse vibration of an axially moving string is developed, and the angle of the incident wave to the right boundary, which is the input of the velocity boundary controller, is obtained. Experimental research is carried out to examine the validity and the performance of the transverse vibration control using the suggested velocity right boundary control scheme.

Real-time Semi-active Vibration Control in Cable-stayed Bridges by Shear-type MR damper and Clipped-optimal Control Algorithm (전단형 MR 댐퍼 및 Clipped-optimal 제어알고리즘을 이용한 사장교의 실시간 준능동 진동제어)

  • Heo, Gwanghee;Jeon, Joonryong;Jeon, Seunggon
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.2
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    • pp.113-123
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    • 2016
  • This paper is concerned with an experimental research to control of random vibration caused by external loads specially in cable-stayed bridges which tend to be structurally flexible. For the vibration control, we produced a model structure modelled on Seohae Grand Bridge, and we designed a shear type MR damper. On the center of its middle span, we placed a shear type MR damper which was to control its vibration and also acquire its structural responses such as displacement and acceleration at the same site. The experiments concerning controlling vibration were performed according to a variety of theories including un-control, passive on/off control, and clipped-optimal control. Its control performance was evaluated in terms of the absolute maximum displacements, RMS displacements, the absolute maximum accelerations, RMS accelerations, and the total power required to control the bridge which differ from each different experiment method. Among all the methods applied in this paper, clipped-optimal control method turned out to be the most effective to reduces of displacements, accelerations, and external power. Finally, It is proven that the clipped-optimal control method was effective and useful in the vibration control employing a semi-active devices such MR damper.

Active Vibration Control of a Opened Box Structure By a Model Reference Neuro-Controller (모델기반 신경망 제어기를 이용한 열린 박스 구조물의 진동제어)

  • Jang, Seung-Ik;Shen, Yun-De;Kee, Chang-Doo
    • Proceedings of the KSME Conference
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    • pp.1602-1607
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    • 2003
  • Vibration causes noise and sometimes makes structure unstable. Especially, due to the efforts of lightening, deformation of flexible structure is increased in its shape. Just a little disturbance can cause vibration and low damping ratio makes residual vibration last long time. This research is concerned with the model reference neuro-controller design for the vibration suppression of smart structures. By using a model reference neurocontroller, which is one of the algorithms of adaptive control, we performed an adaptive control of flexible cantilever plate and opened box structure with piezoelectric materials. The proposed adaptive vibration control algorithm, a model reference neuro-controller, was proved in its effectiveness by applying to an opened box structure. The model reference neuro-controller is implemented with DSP, and the real-time adaptive vibration control experiment results confirm that the model reference neuro-controller is reliable.

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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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Analysis and active control for wind induced vibration of beam with ACLD patch

  • Li, Jinqiang;Narita, Yoshihiro
    • Wind and Structures
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    • v.17 no.4
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    • pp.399-417
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    • 2013
  • The structural vibration suppression with active constrained layer damping (ACLD) was widely studied recently. However, the literature seldom concerned with the vibration control on flow-induced vibration using active constrained layer. In this paper the wind induced vibration of cantilevered beam is analyzed and suppressed by using random theory together with a velocity feedback control strategy. The piezoelectric material and frequency dependent viscoelastic layer are used to achieve effective active damping in the vibration control. The transverse displacement and velocity in time and frequency domains, as well as the power spectral density and the mean-square value of the transverse displacement and velocity, are formulated under wind pressure at variable control gain. It is observed from the numerical results that the wind induced vibration can be significantly suppressed by using a small outside active voltage on the constrained layer.

Vibration Control of a Single-Link Flexible Manipulator Using Reaction Moment Estimator (반력모멘트 추정기를 이용한 단일 링크 유연 조작기의 진동제어)

  • Shin, Hocheol;Han, Sangsoo;Kim, Seungho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.2
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    • pp.169-175
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    • 2005
  • In this paper, a novel vibration control scheme for a single-link flexible manipulator system without using a vibration feedback sensor is proposed. In order to achieve the vibration information of the flexible link, a reaction moment estimator based on the dynamic characteristics of the flexible manipulator is proposed. While the manipulator is maneuvering the reaction moment is reciprocally acting on the flexible link and the hub inertia due to the vibration of the link. A sliding mode controller based on the equivalent rigid body dynamics corresponding to the proposed flexible manipulator is then augmented with the reaction moment estimator to realize a decentralized control system. The reaction moment estimator is implemented via the first order low pass filter. The performance of the proposed control scheme is verified by computer simulation and experiment.

Test and Simulation of an Active Vibration Control System for Helicopter Applications

  • Kim, Do-Hyung;Kim, Tae-Joo;Jung, Se-Un;Kwak, Dong-Il
    • International Journal of Aeronautical and Space Sciences
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    • v.17 no.3
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    • pp.442-453
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    • 2016
  • A significant source of vibration in helicopters is the main rotor system, and it is a technical challenge to reduce the vibration in order to ensure the comfort of crew and passengers. Several types of passive devices have been applied to conventional helicopters in order to reduce the vibration. In recent years, helicopter manufacturers have increasingly adopted active vibration control systems (AVCSs) due to their superior performance with lower weight compared with passive devices. AVCSs can also maintain their performance over aircraft configuration and flight condition changes. As part of the development of AVCS software for light civil helicopter (LCH) applications, a test bench is constructed and vibration control tests and simulations are performed in this study. The test bench, which represents the airframe, is excited using a pair of counter rotating force generators (CRFGs) and a multiple input single output (MISO) AVCS that consists of three accelerometer sensors and a pair of CRFGs; a filtered-x least mean square (LMS) algorithm is applied for the vibration reduction. First, the vibration control tests are performed with uniform sensor weights; then, the change in the control performance according to changes in the sensor weight is investigated and compared with the simulation results. It is found that the vibration control performance can be tuned through adjusting the weights of the three sensors, even if only one actuator is used.

A Design of Electromagnet Actuator for Active Vibration Control (능동 진동제어용 전자기 액츄에이터 설계)

  • Lee, Joo-Hoon;Jeon, Jeong-Woo;Hwang, Don-Ha;Kang, Dong-Sik;Choi, Young-Kiu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.522-524
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    • 2005
  • In this paper, we address an actuator system, which suppresses the micro-vibration engaged by environment. The actuator system consists of two modules with a permanent and an electromagnet. In vertical mode, one module is upper the other is lower. For optimal control of alternating vibration, the rate of the attraction force and the repulsion force is exactly one. Generally, the repulsive force is smaller than the attractive force. For linear control of engaged vibration, the ratio of repulsive force and attractive force is designed to equal. The actuator system will be applied to an active vibration control system for precise vibration suppression. In this paper, the actuator structure and its important sizes are calculated by RMS and FEM analysis.

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