Stochastic vibration suppression analysis of an optimal bounded controlled sandwich beam with MR visco-elastomer core

Z.G. Ying,Y.Q. Ni,Y.F. Duan 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.19 No.1

To control the stochastic vibration of a vibration-sensitive instrument supported on a beam, the beam is designed as a sandwich structure with magneto-rheological visco-elastomer (MRVE) core. The MRVE has dynamic properties such as stiffness and damping adjustable by applied magnetic fields. To achieve better vibration control effectiveness, the optimal bounded parametric control for the MRVE sandwich beam with supported mass under stochastic and deterministic support motion excitations is proposed, and the stochastic and shock vibration suppression capability of the optimally controlled beam with multi-mode coupling is studied. The dynamic behavior of MRVE core is described by the visco-elastic Kelvin-Voigt model with a controllable parameter dependent on applied magnetic fields, and the parameter is considered as an active bounded control. The partial differential equations for horizontal and vertical coupling motions of the sandwich beam are obtained and converted into the multi-mode coupling vibration equations with the bounded nonlinear parametric control according to the Galerkin method. The vibration equations and corresponding performance index construct the optimal bounded parametric control problem. Then the dynamical programming equation for the control problem is derived based on the dynamical programming principle. The optimal bounded parametric control law is obtained by solving the programming equation with the bounded control constraint. The controlled vibration responses of the MRVE sandwich beam under stochastic and shock excitations are obtained by substituting the optimal bounded control into the vibration equations and solving them. The further remarkable vibration suppression capability of the optimal bounded control compared with the passive control and the influence of the control parameters on the stochastic vibration suppression effectiveness are illustrated with numerical results. The proposed optimal bounded parametric control strategy is applicable to smart visco-elastic composite structures under deterministic and stochastic excitations for improving vibration control effectiveness.

Simultaneous precision positioning and vibration suppression of reciprocating flexible manipulators

Ma, Kougen,Ghasemi-Nejhad, Mehrdad N. Techno-Press 2005 Smart Structures and Systems, An International Jou Vol.1 No.1

Simultaneous precision positioning and vibration suppression of a reciprocating flexible manipulator is investigated in this paper. The flexible manipulator is driven by a multifunctional active strut with fuzzy logic controllers. The multifunctional active strut is a combination of a motor assembly and a piezoelectric stack actuator to simultaneously provide precision positioning and wide frequency bandwidth vibration suppression capabilities. First, the multifunctional active strut and the flexible manipulator are introduced, and their dynamic models are derived. A control strategy is then proposed, which includes a position controller and a vibration controller to achieve simultaneous precision positioning and vibration suppression of the flexible manipulator. Next, fuzzy logic control approach is presented to design a fuzzy logic position controller and a fuzzy logic vibration controller. Finally, experiments are conducted for the fuzzy logic controllers and the experimental results are compared with those from a PID control scheme consisting of a PID position controller and a PID vibration control. The comparison indicates that the fuzzy logic controller can easily handle the non-linearity in the strut and provide higher position accuracy and better vibration reduction with less control power consumption.

준능동형 실시간 Feedback 진동제어시스템의 성능평가

허광희,전준용 한국구조물진단유지관리공학회 2011 한국구조물진단유지관리공학회 논문집 Vol.15 No.1

본 논문에서는 구조적으로 유연한 특성을 갖는 교량 구조물을 대상으로 외력에 의해 발생되는 진동을 실시간으로 제어하고자 준능동형 실시간 피드백 진동제어시스템을 구성하고, 이를 실험적으로 평가하였다. 여기서 진동제어를 위한 대상 교량 구조물은 서해대교를 약 1/200 크기로 규모화 하여 설계/제작한 모형 교량 구조물을 사용하였고, 실험실 여건을 고려해 규모화 된El-centro 지진파형으로 구조물을 가진하였다. 또한, 교량 상판 중앙지점에는 전자석이 채용된 전단형 MR 댐퍼를 수직방향으로 설치하여 발생된 진동을 제어하도록 하였고, 동시에 변위계 및 가속도계를 설치하여 구조물의 응답(변위, 가속도)을 획득하였다. 이때 진동제어의 실험은 크게 비-제어, 수동 on/off 제어, Lyapunov 안정론 기반 제어 그리고, Clipped-optimal 제어조건으로 구분하여 실시간 피드백 진동제어실험을 수행하였고, 이때 진동제어의 효과는 상판 중앙지점에 대하여 각 실험방법 별절대최대변위와 절대최대가속도 그리고, 인가전원의 소모량 등을 성능지수를 이용해 정량적으로 평가하였다. 진동제어실험의 결과로부터, Lyapunov 제어 및 Clipped-optimal 제어방법 모두 구조물의 발생 변위 및 가속도를 효과적으로 감소시켰으며, 특히 진동제어 시 요구되는 외부 인가전원의 소비를 크게 감소시킬 수 있음을 확인하였다. 최종적으로, 본 논문에서 구성한 준능동형 실시간 피드백 진동제어시스템은 교량 구조물에 발생된 진동을 제어 ․관리하기 위한 적극 ․ 효율적인 방법으로 활용될 가능성이 있음을 확인하였다. This paper is concerned to constitute a semi-active realtime feedback vibration control system and evaluate it through experiments in order to control in realtime the vibration externally generated, specially on the bridges which is structurally flexible. For the experiment of vibration control, we built a model bridge structure of Seohae Grand Bridge in a 1/200 reduced form and inflicted El-centro wave on the model structure also in a reduced force considering the lab condition. The externally excited vibration was to be controled by placing a shear type MR damper vertically on the center of bridge span, and the response (displacement and acceleration) of structure was to be acquired by placing LVDT and Accelerometer at the same time. As for the experiment concerning controlling vibration, a realtime feedback vibration control experiments were performed under each different condition largely such as un-control, passive on/off control, Lyapunov stability theory control, and Clipped-optimal control. Its control performance under different condition was quantitatively evaluated in terms of the peak absolute displacements, the peak absolute accelerations and the power required for control on the center of span. The results of experiments proved that the Lyapunov control and clipped-iptimal control were effective to decrease the displacement and acceleration of the structure, and also to decrease the power consumption to a great extent. Finally, the semi-active realtime feedback vibration control system constituted in this research was proven to be an effective way to control and manage the vibration generated on bridge structure.

Active Vibration Isolator with Feed-forward Augmented Control Taking Account of Dynamics of Elastic Load

Junya HIJIOKA,Hazime SHIRAISHI,Toru WATANABE,Kazuto SETO 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.춘계 No.-

This paper deals with control system design for active isolation table. If elastic loads are put on the isolation table, vibration modes of the table are changed. Therefore, the controllers for the active isolation table should be designed taking account of elastic loads. According to this fact, a dynamical model must be identified that takes the dynamics of elastic loads into consideration for such controllers. In this research, an experimental active isolation table with an elastic load is built. Its dynamical model is identified by using experimental modal analysis or FEM analysis. A controller is designed by using the model according to sub-optimal control theory, absolute velocity feed-back control theory and feed-forward control theory. Property of the obtained controller is qualified through computer simulations and control experiments.

Vibration control of membrane structures using multiple dielectric elastomer actuators

Toshiki Hiruta,Hiroki Ishihara,Naoki Hosoya,Shingo Maeda,Itsuro Kajiwara 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

A vibration suppression technique for lightweight and flexible membrane structures is proposed using smart structure technology with a dielectric elastomer actuator (DEA). DEA is a lightweight flexible polynomial material with a large deformation and high response time. Its advantages include easy application to the membrane structures and vibration suppression over a wide frequency band. A non-contact excitation system using a high-power Nd:YAG pulsed laser is used to precisely measure the vibration responses of membrane structures. The system generates a highly reproducible ideal impulse excitation. Active vibration control for membrane structures with DEAs is examined in this study. To improve the vibration control effect, multiple DEAs are applied. These actuators generate vibration control forces simultaneously during the control. Laminated DEAs are fabricated and attached to the membrane surface separately. An experimental setup including a digital control system is constructed with the laser excitation system. To demonstrate the effectiveness of the proposed method, a controller is designed by H∞ control theory with the identified membrane model and vibration control experiments are conducted.

프로펠라 샤프트의 능동진동제어 시스템

이재문(Jae-Mun Lee),이철희(Chul-Hee Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

This paper presents a solution of the vibration reduction in the Propeller shafts. Generally, the vibration mode in propeller shafts can be divided into the bending and torsional vibrations. And the bending vibration is significant factor when it excites with the resonance frequencies in the propeller shafts. However, since the torsional vibration is also the critical source of vibration problem in the propeller shaft, it is necessary to analyze bending and torsion vibration together with the natural frequencies. In this paper, active vibration control system of propeller shafts is introduced to actively absorb the combined bending and torsional vibrations. Proposed active damping structure is built by embedding the piezofiber actuators that are composed of piezopatches based on the Macro Fiber Composite (MFC) technology. The MFC is an innovative actuator that offers high performance and flexibility. The MFC consists of rectangular piezo ceramic rods sandwiched between layers of adhesive and electroded polyimide film, which is heat and chemical resistant polymers. Since the MFC patch is more flexible, durable and powerful than other piezo-materials, it is the best candidate of actuator to apply to the curved surface of the shaft. In order to calculate the vibration modes in the propeller shafts, analytical method and Finite Element Method are used. And to simulate effect of vibration damping, Piezoelectric-thermal analysis is used, too. Experimental investigations are also conducted by PID controller. For the desired vibration damping performance with the limited number of MFC actuators, PID controller is designed and its gains are tuned. Finally, control results are shown. So, the results provide an outlook for the active control using the multi-mode resonance controllers.

Multicyclic Vibration Control of a Helicopter Rotor with Active Twist Actuation

김도형,홍성현,정성남 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.2

The vibration control performance of a Mach scaled Bo-105 rotor is evaluated using the active twist multicyclic control. The simulation data for the baseline flight condition are generated using CAMRAD II. A linear, quasi-static, frequency domain model with up to 6 multicyclic higher harmonic control inputs and 12 harmonic response outputs of non-rotating hub loads are identified offline by the least squared error estimate. The optimal control input for minimizing the quadratic performance function along with the output response to the optimal control are calculated. The vibration reduction performances with the obtained optimal control input are examined. The single harmonic control results show close agreement with the low vibration conditions by the amplitude and phase sweep method. When the multicyclic control is applied, the vibration reduction performance is improved compared to the single harmonic control case, and the hub vibration is reduced by up to 64%. A coupling of MATLAB and CAMRAD II is used to evaluate closed-loop multicyclic control systems. The coupled closed-loop analysis result shows good agreement with the simulation result using identified linear system model. The closed-loop control using the gradient descent algorithm shows excellent vibration reduction performance with the reduced vibration level converges to the optimal solution.

Active vibration control of clamped beams using positive position feedback controllers with moment pair

Shin, Chang-Joo,Hong, Chin-Suk,Jeong, Weui-Bong 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.3

This paper investigates the active vibration control of clamp beams using positive position feedback (PPF) controllers with a sensor/ moment pair actuator. The sensor/moment pair actuator which is the non-collocated configuration leads to instability of the control system when using the direct velocity feedback (DVFB) control. To alleviate the instability problem, a PPF controller is considered in this paper. A parametric study of the control system with PPF controller is first conducted to characterize the effects of the design parameters (gain and damping ratio in this paper) on the stability and performance. The gain of the controller is found to affect only the relative stability. Increasing the damping ratio of the controller slightly improves the stability condition while the performance gets worse. In addition, the higher mode tuned PPF controller affects the system response at the lower modes significantly. Based on the characteristics of PPF controllers, a multi-mode controllable SISO PPF controller is then considered and tuned to different modes (in this case, three lowest modes) numerically and experimentally. The multi-mode PPF controller can be achieved to have a high gain margin. Moreover, it reduces the vibration of the beam significantly. The vibration levels at the tuned modes are reduced by about 11 dB.

Performance evaluation of inerter-based damping devices for structural vibration control of stay cables

Zhiwen Huang,Xugang Hua,Zhengqing Chen,Huawei Niu 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.6

Inerter-based damping devices (IBBDs), which consist of inerter, spring and viscous damper, have been extensively investigated in vehicle suspension systems and demonstrated to be more effective than the traditional control devices with spring and viscous damper only. In the present study, the control performance on cable vibration reduction was studied for four different inerter-based damping devices, namely the parallel-connected viscous mass damper (PVMD), series-connected viscous mass damper (SVMD), tuned inerter dampers (TID) and tuned viscous mass damper (TVMD). Firstly the mechanism of the ball screw inerter is introduced. Then the state-space formulation of the cable-TID system is derived as an example for the cable-IBBDs system. Based on the complex modal analysis, single-mode cable vibration control analysis is conducted for PVMD, SVMD, TID and TVMD, and their optimal parameters and the maximum attainable damping ratios of the cable/damper system are obtained for several specified damper locations and modes in combination by the Nelder-Mead simplex algorithm. Lastly, optimal design of PVMD is developed for multi-mode vibration control of cable, and the results of damping ratio analysis are validated through the forced vibration analysis in a case study by numerical simulation. The results show that all the four inerter-based damping devices significantly outperform the viscous damper for single-mode vibration control. In the case of multi-mode vibration control, PVMD can provide more damping to the first four modes of cable than the viscous damper does, and their maximum control forces under resonant frequency of harmonic forced vibration are nearly the same. The results of this study clearly demonstrate the effectiveness and advantages of PVMD in cable vibration control.

전단형 MR 댐퍼 및 Clipped-optimal 제어알고리즘을 이용한 사장교의 실시간 준능동 진동제어

허광희,전준용,전승곤 한국지진공학회 2016 한국지진공학회논문집 Vol.20 No.2

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.