An Active Microvibration Isolation System for Hi-tech Manufacturing Facilities

2000 ◽  
Vol 123 (2) ◽  
pp. 269-275 ◽  
Author(s):  
H. Yoshioka ◽  
Y. Takahashi ◽  
K. Katayama ◽  
T. Imazawa ◽  
N. Murai
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Tuned Mass Damper ◽  
Impact Excitation ◽  
Frequency Range ◽  
Isolation System ◽  
Linear Motors ◽  
Assignment Method ◽  
Mass Damper ◽  
Bending Modes

This paper presents an active microvibration isolation system using voice-coil linear motors, and pneumatic and piezoelectric actuators. This system is designed to reduce microvibration of the six degrees-of-freedom associated with the rigid body modes of the vibration isolation table by feeding back the pseudo absolute displacement and velocity of the table. To improve vibration isolation performance, a feed-forward control link is added to the sway components in each dimension. This system can also control bending modes of the table in the frequency range up to 200 Hz by employing a proposed Virtual Tuned-Mass Damper control strategy, which is a type of the pole assignment method. In this approach, the pole locations are chosen by a genetic algorithm. For ambient microvibration of the floor around 0.5 cm/s2 and for small earthquakes of around 8 cm/s2 a reduction by a factor of 100 was achieved in the acceleration of the vibration isolation table. Moreover, the vibration of the isolation table was decreased over the entire frequency range. This system also showed good vibration control performance when an impact excitation was applied directly to the table; vibration was damped out within about 0.1 sec. Additionally, the resonance amplitudes around the bending modes of the table were reduced from 1/5 to 1/15 by the Virtual Tuned-Mass Damper method.

scholarly journals KDamping: A stiffness based vibration absorption concept

2016 ◽  
Vol 24 (3) ◽  
pp. 588-606 ◽  
Author(s):  
Ioannis A Antoniadis ◽  
Stratis A Kanarachos ◽  
Konstantinos Gryllias ◽  
Ioannis E Sapountzakis
Keyword(s):  
Vibration Isolation ◽  
Tuned Mass Damper ◽  
Negative Stiffness ◽  
Damping Properties ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Load Bearing Capacity ◽  
Vibration Absorption ◽  
Mass Damper ◽  
Elastic Forces

The KDamper is a novel passive vibration isolation and damping concept, based essentially on the optimal combination of appropriate stiffness elements, which include a negative stiffness element. The KDamper concept does not require any reduction in the overall structural stiffness, thus overcoming the corresponding inherent disadvantage of the “Quazi Zero Stiffness” (QZS) isolators, which require a drastic reduction of the structure load bearing capacity. Compared to the traditional Tuned Mass damper (TMD), the KDamper can achieve better isolation characteristics, without the need of additional heavy masses, as in the case of the T Tuned Mass damper. Contrary to the TMD and its variants, the KDamper substitutes the necessary high inertial forces of the added mass by the stiffness force of the negative stiffness element. Among others, this can provide comparative advantages in the very low frequency range. The paper proceeds to a systematic analytical approach for the optimal design and selection of the parameters of the KDamper, following exactly the classical approach used for the design of the Tuned Mass damper. It is thus theoretically proven that the KDamper can inherently offer far better isolation and damping properties than the Tuned Mass damper. Moreover, since the isolation and damping properties of the KDamper essentially result from the stiffness elements of the system, further technological advantages can emerge, in terms of weight, complexity and reliability. A simple vertical vibration isolation example is provided, implemented by a set of optimally combined conventional linear springs. The system is designed so that the system presents an adequate static load bearing capacity, whereas the Transfer Function of the system is below unity in the entire frequency range. Further insight is provided to the physical behavior of the system, indicating a proper phase difference between the positive and the negative stiffness elastic forces. This fact ensures that an adequate level of elastic forces exists throughout the entire frequency range, able to counteract the inertial and the external excitation forces, whereas the damping forces and the inertia forces of the additional mass remain minimal in the entire frequency range, including the natural frequencies. It should be mentioned that the approach presented does not simply refer to discrete vibration absorption device, but it consists a general vibration absorption concept, applicable also for the design of advanced materials or complex structures. Such a concept thus presents the potential for numerous implementations in a large variety of technological applications, whereas further potential may emerge in a multi-physics environment.

A Variable Stiffness Vibration Isolation System Based on Magneto-Rheological Elastomer

2012 ◽  
Vol 452-453 ◽  
pp. 659-662
Author(s):  
Wei Wang ◽  
Yi Min Deng
Keyword(s):  
Shear Modulus ◽  
Vibration Isolation ◽  
Variable Stiffness ◽  
Control Area ◽  
Frequency Range ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Isolators ◽  
Magneto Rheological ◽  
Conventional Type

Vibration isolation is a most widely used vibration protection method.The stiffness of vibration isolators in existing conventional type of vibration isolation system is usually of fixed value. This limits the system in exhibiting its vibration isolation effect in that, it has poor results for lower frequency vibration, especially for resonance frequency. Magneto-rheological elastomer is a new branch of Magneto-rheological materials. It’s an intelligent materials in that it’s shear modulus can be controlled by a magnetic field. It has wide application prospects in the vibration control area. This paper proposes using adjustable stiffness of magneto-rheological elastomer vibration isolation in vibration isolation system. By changing the current of vibration isolators coil to control the shear modulus of magneto-rheological elastomer, it can adjust the stiffness of the isolation system, making the system obtain wider vibration isolation frequency range. By exploying SimuLink software to analyze the vibration isolation system, it is found that such a design is effective and applicable.

Theory and Method of Dynamic Modeling for Multilayer Vibration Isolation System

2000 ◽  
Author(s):  
Liao Dao-Xun ◽  
Lu Yong-Zhong ◽  
Huang Xiao-Cheng
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Rigid Bodies ◽  
Design Calculation ◽  
Isolation System ◽  
Dry Land ◽  
Vibration Isolation System ◽  
Six Degrees Of Freedom ◽  
Floating Raft

Abstract The multilayer vibration isolation system has been widely applied to isolate vibration in dynamic devices of ships, high-speed vehicles forging hammer and precise instruments. The paper is based on the coordinate transformation of space general motion for mass blocks (rigid bodies) and Lagrangian equation of multilayer vibration isolation system. It gives a strict mathematical derivation on the differential equation of the motion for the system with six degrees of freedom of relative motion between mass blocks (including base). The equations are different from the same kind of equations in the reference literatures. It can be used in the floating raft of ships in order to isolates vibration and decrease noise, also used in design calculation of the multilayer vibration isolation for dynamic machines and precise instruments on the dry land.

Modeling Research for Active Control of Coupled Vibration between Multiple CNC Milling Machines and Flexible Foundation

2011 ◽  
Vol 105-107 ◽  
pp. 675-679 ◽  
Author(s):  
Fu Dong Ma ◽  
Yao Gang Li ◽  
Qian Lin Peng
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Lagrange Equation ◽  
Real Life ◽  
Traditional Theory ◽  
Cnc Milling ◽  
Isolation System ◽  
Milling Machines ◽  
Flexible Foundation ◽  
Multiple Machines

In real life many agencies are using the flexible foundation as a base of support, such as ship hull or deck, the chassis of car, and machine tools work on stairs. With the traditional theory, the mathematical model between machine and based simplified as single-degree-of-freedom, assuming foundation is a rigid, and many investigate for a single machine, ignoring the dynamic coupling of base and the coupling characteristics between vibrators. This paper build a dynamics model with flexible basis and multiple machines, it’s multi-degrees-of-freedom model. The foundation is flexibled. On this basis builiding a model about multiple machines, flexible foundation and vibration isolation system. This paper resolve to the problem of the machine work on stair, research the system include vibrator, actuators, and flexible foundation. Using Lagrange equation deduce dynamics equation. Express every factor in eqution,deduced the state and space expression.Take prepare for optimal and system simulation.

scholarly journals Performance of TMDI for Tall Building Damping

Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 139
Author(s):  
Felix Weber ◽  
Peter Huber ◽  
Fredrik Borchsenius ◽  
Christian Braun
Keyword(s):  
Mass Matrix ◽  
Vibration Reduction ◽  
Tuned Mass Damper ◽  
Tall Building ◽  
Realistic Case ◽  
Absolute Acceleration ◽  
The Earth ◽  
Mass Damper ◽  
The Absolute ◽  
Bending Modes

This study investigates the vibration reduction of tall wind-excited buildings using a tuned mass damper (TMD) with an inerter (TMDI). The performance of the TMDI is computed as a function of the floor to which the inerter is grounded as this parameter strongly influences the vibration reduction of the building and for the case when the inerter is grounded to the earth whereby the absolute acceleration of the corresponding inerter terminal is zero. Simulations are made for broadband and harmonic excitations of the first three bending modes, and the conventional TMD is used as a benchmark. It is found that the inerter performs best when grounded to the earth because, then, the inerter force is in proportion to the absolute acceleration of only the pendulum mass, but not to the relative acceleration of the two inerter terminals, which is demonstrated by the mass matrix. However, if the inerter is grounded to a floor below the pendulum mass, the TMDI only outperforms the TMD if the inerter is grounded to a floor within approximately the first third of the building’s height. For the most realistic case, where the inerter is grounded to a floor in the vicinity of the pendulum mass, the TMDI performs far worse than the classical TMD.

scholarly journals Modeling and Control of a Six Degrees of Freedom Maglev Vibration Isolation System

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3608 ◽  
Author(s):  
Qianqian Wu ◽  
Ning Cui ◽  
Sifang Zhao ◽  
Hongbo Zhang ◽  
Bilong Liu
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Nonlinear Dynamic Model ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Modeling And Control ◽  
And Control ◽  
Isolation Performance

The environment in space provides favorable conditions for space missions. However, low frequency vibration poses a great challenge to high sensitivity equipment, resulting in performance degradation of sensitive systems. Due to the ever-increasing requirements to protect sensitive payloads, there is a pressing need for micro-vibration suppression. This paper deals with the modeling and control of a maglev vibration isolation system. A high-precision nonlinear dynamic model with six degrees of freedom was derived, which contains the mathematical model of Lorentz actuators and umbilical cables. Regarding the system performance, a double closed-loop control strategy was proposed, and a sliding mode control algorithm was adopted to improve the vibration isolation performance. A simulation program of the system was developed in a MATLAB environment. A vibration isolation performance in the frequency range of 0.01–100 Hz and a tracking performance below 0.01 Hz were obtained. In order to verify the nonlinear dynamic model and the isolation performance, a principle prototype of the maglev isolation system equipped with accelerometers and position sensors was developed for the experiments. By comparing the simulation results and the experiment results, the nonlinear dynamic model of the maglev vibration isolation system was verified and the control strategy of the system was proved to be highly effective.

Analysis of Nonlinear Cyclically Symmetric Isolation Sistem of a Cargo in a Container under Plane Harmonic Vibrations

2021 ◽  
pp. 32-50
Author(s):  
A.E. Belkin ◽  
I.Z. Dashtiev ◽  
E.A. Nikitin
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Excitation Amplitude ◽  
High Energy ◽  
Symmetric System ◽  
Model Framework ◽  
Isolation System ◽  
Kinematic Excitation ◽  
Shock Absorbers ◽  
High Energy Absorption

The problem of calculating the system of a cylindrical shaped load transverse damping installed in a coaxial container is considered. This system has several annular belts of insulation with a cyclically symmetric arrangement of shock absorbers along the circumferential direction. A simple dynamic model of one insulation belt formed by polyurethane tunnel-type shock absorbers is investigated. Such shock absorbers have a high energy absorption coefficient and can operate at very high drafts comparable to their height, which is important when the space between the cargo and the container wall is limited. Within the proposed model framework, a harmonic nonlinear analysis of cargo plane oscillations under kinematic excitation coming from the container is considered. A method for reducing a nonlinear cyclically symmetric system with discrete elastic elements, which allows limiting the analysis to the calculation of a vibration isolation system with one degree of freedom, is proposed. Using the harmonic linearization procedure, the amplitude-frequency characteristics of oscillations and plots of vibration isolation coefficients of cargo at different values of excitation amplitude have been obtained. The results are verified by comparing the analytical solution with the results of numerical integration for a non-reduced nonlinear system with two degrees of freedom. The obtained solution allows choosing the vibration isolation belt parameters, in particular the number of shock absorbers and their stiffness, depending on the conditions of kinematic excitation and permissible overload

Development of Six Degrees of Freedom Vibration Isolation System for Microgravity Environment

1995 ◽  
Author(s):  
Toshiyuki Suzuki ◽  
Koji Tanida ◽  
Akira Tanji ◽  
Koichi Okubo
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Parabolic Flight ◽  
Microgravity Environment ◽  
External Disturbances ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Six Degrees Of Freedom ◽  
Active Vibration ◽  
Good Agreement

Abstract An active vibration isolation system, under development for use in microgravity environment, provides electromagnetic suspension by means of voice coils arranged in pairs to control the translational and rotational movements of the payload, three pairs of which cover the three axes to ensure control of payload movement in all six degrees of freedom. A series of tests performed on this system in microgravity environment created by parabolic flight proved that external disturbances in frequencies above 0.1 Hz were effectively reduced by applying the system. Also, good agreement was obtained between the measured performance and results of numerical simulation.

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