Double‐pendulum vibration isolator or seismograph

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

Download Full-text

Fulfillment of Arbitrary Movement Transfer Control between Equilibrium States for a Double Pendulum Robot

ACTA AUTOMATICA SINICA ◽

10.3724/sp.j.1004.2010.01720 ◽

2011 ◽

Vol 36 (12) ◽

pp. 1720-1731 ◽

Cited By ~ 1

Author(s):

Zu-Shu LI ◽

Yuan-Hong DAN ◽

Xiao-Chuan ZHANG ◽

Lin XIAO ◽

Zhi TAN

Keyword(s):

Equilibrium States ◽

Double Pendulum

Download Full-text

Beneficial performance of a quasi-zero stiffness vibration isolator with generalized geometric nonlinear damping

Noise & Vibration Worldwide ◽

10.1177/0957456520972385 ◽

2020 ◽

pp. 095745652097238

Author(s):

Chun Cheng ◽

Ran Ma ◽

Yan Hu

Keyword(s):

Damping Ratio ◽

Nonlinear Damping ◽

Vibration Isolator ◽

Equivalent Damping ◽

Frequency Responses ◽

Geometric Nonlinear ◽

Resonant Region ◽

Force Transmissibility ◽

Isolation Performance ◽

Force And Displacement Transmissibility

Generalized geometric nonlinear damping based on the viscous damper with a non-negative velocity exponent is proposed to improve the isolation performance of a quasi-zero stiffness (QZS) vibration isolator in this paper. Firstly, the generalized geometric nonlinear damping characteristic is derived. Then, the amplitude-frequency responses of the QZS vibration isolator under force and base excitations are obtained, respectively, using the averaging method. Parametric analysis of the force and displacement transmissibility is conducted subsequently. At last, two phenomena are explained from the viewpoint of the equivalent damping ratio. The results show that decreasing the velocity exponent of the horizontal damper is beneficial to reduce the force transmissibility in the resonant region. For the case of base excitation, it is beneficial to select a smaller velocity exponent only when the nonlinear damping ratio is relatively large.

Download Full-text