scholarly journals Experimental demonstration of 1.5Hz passive isolation system for precision optical payloads

2017 ◽  
Author(s):  
Guang-yuan Wang ◽  
Xiang Chen ◽  
Xin Guan ◽  
Dong-jing Cao ◽  
Shao-fan Tang ◽  
...  
Keyword(s):  
Experimental Demonstration ◽  
Isolation System ◽  
Passive Isolation

Virtual Skyhook Vibration Isolation System

2001 ◽  
Vol 124 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Steve Griffin ◽  
Joel Gussy ◽  
Steven A. Lane ◽  
Benjamin K. Henderson ◽  
Dino Sciulli
Keyword(s):  
Vibration Isolation ◽  
Experimental Measurements ◽  
Simple Test ◽  
Experimental Demonstration ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Design And Implementation ◽  
At Resonance ◽  
Model Predictions ◽  
Passive Isolation

This work presents and demonstrates a passive isolation system that offers the performance of a skyhook damper, but without the need of an inertial reference. This “virtual skyhook” isolation system can be used to reduce the transmission of base excitations to a structure. An analysis of the concept is presented, and model predictions are compared to experimental measurements for a simple test structure. The results demonstrate that the proposed isolation system significantly attenuates transmissibility at resonance without the penalty of increased transmissibility at higher frequencies, which often limits the performance of passive approaches. Practical issues regarding the design and implementation of the virtual skyhook vibration isolation system are also presented and discussed. To the best of the authors’ knowledge, this is the first experimental demonstration of an entirely passive skyhook damper isolation system.

Sliding-Mode Control Algorithm for a Hard-Mounted Isolation System

2007 ◽  
Author(s):  
Yung-Peng Wang ◽  
Jen-Chieh Tsao
Keyword(s):  
Sliding Mode Control ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Isolation System ◽  
Mode Control ◽  
Active Isolation ◽  
Ultra Precision ◽  
Passive Isolation ◽  
Isolation Systems ◽  
Isolation Performance

It is well known that the trend of current technology development is microscopic and ultra-precision, especially in the areas of semiconductor manufacturing, ultra-precision machining, MEMS, microbiology and nanotechnology. Hence, vibration becomes a significant problem in those fields. There are two types of vibration control techniques. One is passive isolation system; the other is active isolation system. Passive isolation system can provide better performance for higher frequencies. Active isolation system is used to improve the isolation performance for lower frequencies. However, passive isolation system has bad performance around the natural frequency. In addition, it cannot eliminate the effects of onboard disturbances. Therefore, active isolation system becomes the major technology in the applications of microvibration control for precision equipment. In practice, all active isolation systems are based upon a hybrid concept, combining a passive isolator for higher frequencies and a servo control system for lower frequencies. This combination allows for two significantly different configurations, which can be categorized as: soft-mounted isolation systems and hard-mounted isolation systems. The soft-mounted systems are inherently insensitive to resonance in the main structure below the isolators. Yet, they are sensitive to resonances in the isolated platform. The hard-mounted systems are extremely stiff and allows for large onboard disturbance forces without excessive motion. However, the major drawback with a hard-mounted system is that vibration isolation performance suffers from the passive-active compromise and is unable to come up to the optimal performance. In this paper, a sliding-mode control algorithm is developed for a hard-mounted isolation system with a piezoactuator. Based on the bounds of environmental vibrations and onboard disturbances, the sliding-mode control algorithm can make the hard-mounted isolation system achieve the optimal and robust performance of low vibration transmissibility and high stiffness. The results are verified by the numerical simulations.

Development and simulation evaluation of a magnetorheological elastomer isolator for seat vibration control

2012 ◽  
Vol 23 (9) ◽  
pp. 1041-1048 ◽  
Author(s):  
Weihua Li ◽  
Xianzhou Zhang ◽  
Haiping Du
Keyword(s):  
Vibration Control ◽  
Vibration Energy ◽  
Magnetorheological Elastomer ◽  
Isolation System ◽  
Road Crashes ◽  
Seat Suspension ◽  
Simulation Evaluation ◽  
Passive Isolation ◽  
Seat Vibration ◽  
Vehicle Seat

Driver fatigue is one of the leading factors contributing to road crashes. Environmental stress, such as unwanted seat vibration, is a key contributor to fatigue. This article presents the design and development of a magnetorheological elastomer isolator for a seat suspension system. By altering the magnetorheological elastomer isolator’s stiffness through a controllable magnetic field and selecting suitable control strategy, the system’s natural frequency can be changed to avoid resonance, which consequently reduce the vehicle’s vibration energy input to seat, and thus suppress the seat’s response. Experimental results show that the developed magnetorheological elastomer isolator is able to reduce vibration more when compared with the passive isolation system, indicating the significant potential of its application in vehicle seat vibration control.

Shaking Table Tests on a Passive Equipment Isolation System for Earthquake Protection

2009 ◽  
Author(s):  
Maurizio De Angelis ◽  
Salvatore Perno ◽  
Anna Reggio ◽  
Gerardo De Canio ◽  
Nicola Ranieri
Keyword(s):  
Steel Frame ◽  
Shaking Table ◽  
Frame Structure ◽  
Shaking Table Tests ◽  
Isolation System ◽  
Industrial Plants ◽  
Steel Frame Structures ◽  
Rigid Mass ◽  
Passive Isolation ◽  
Steel Frame Structure

The present work refers to steel frame structures in industrial plants. A passive isolation system for seismic protection of a considerable equipment, already present on a frame support structure and rigidly constrained to it, is investigated through both numerical simulations (1+1 DOF system) and shaking table tests on a 1:5 scale two-story steel frame structure. The equipment (e.g. a pipeline, a compressor unit, ...) is modelled as a rigid mass. The optimal design is determined by minimizing the dynamic response of the isolated mass. In order to ensure strenght and serviceability, the response of the frame is also monitored.

Dynamic Modeling and Analysis of Mechanical Snubbing

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Sudhir Kaul
Keyword(s):  
Parameter Identification ◽  
Small Range ◽  
Time Varying ◽  
Isolation System ◽  
Modeling And Analysis ◽  
Modeling Analysis ◽  
Time Varying Parameter ◽  
Identification Technique ◽  
Passive Isolation ◽  
Force Displacement

This paper presents four alternate models of varying complexity to examine mechanical snubbing in elastomeric isolators. Although the modeling, analysis, and experimentation presented is limited to snubbing of elastomeric isolators, the models are generic and can be adapted to other snubbing mechanisms as well, such as friction snubbing. Two of the four models presented in this paper use the Bouc–Wen model in order to capture hysteresis and gradual stiffening behavior, which is generally exhibited by elastomeric snubbing systems. The other two models are relatively simplistic and do not account for a time-varying parameter to model significant hysteresis. However, these two models can still be useful for applications with a small range of excitation frequencies and for applications where the snubbing design needs to incorporate an abrupt transition in stiffness. A parameter identification technique is used to determine the variables associated with each model. The parameter identification technique is based on the use of an optimization algorithm associated with the force–displacement characterization. All four models presented in this paper capture the coupled dynamics of the isolation system and the snubbing system and are, therefore, a significant improvement upon the currently used models. The models presented are expected to facilitate the design and analysis of a passive isolation system in conjunction with the design of the snubbing system and the base frame supporting the snubbing system.

scholarly journals Passive impact/vibration control and isolation performance optimization for space noncooperative target capture

2020 ◽  
Vol 17 (1) ◽  
pp. 172988141989538
Author(s):  
Chong Sun ◽  
Xiaolei Hou
Keyword(s):  
Performance Optimization ◽  
Optimization Method ◽  
Nonlinear Damping ◽  
Isolation System ◽  
Capture Process ◽  
Target Capture ◽  
Passive Isolation ◽  
The Impact ◽  
Impact Vibration ◽  
Isolation Performance

On-orbit capture is an important technique for the space debris removal, refueling, or malfunction satellite repairing. While due to the uncertainty of the motion parameters of the space noncooperative target, the impact between the capture device and the noncooperative target during the capturing process is inevitable, which may bring strong vibration perturbation to the base satellite, and potentially alter the position and the attitude of the servicing spacecraft, or even cause failure of on-orbit tasks. This article presents a new and alternative method for passive suppression of spacecraft impact and perturbation during noncooperative spacecraft capture. The passive device based on bioinspired X-shape is installed between the satellite and the capture device. In the capture process, nonlinear damping of the passive isolation structure can significantly reduce impact/vibration perturbation. For performance analysis, dynamic equations of the isolation system are established. Based on which, the relationship between structure parameters and isolation performance is systematically analyzed. Experiments are conducted for verification of the effectiveness of the proposed method. Moreover, an optimal process using the non-dominated sorting genetic algorithm II optimization method is developed to minimize impact/vibration perturbation effect, and optimal solutions can provide useful reference for the passive isolation system design.

Integration of an omnidirectional self-powering component to an MRE isolator towards a smart passive isolation system

2020 ◽  
Vol 144 ◽  
pp. 106853
Author(s):  
J. Yang ◽  
M.D. Christie ◽  
S. Sun ◽  
D. Ning ◽  
M. Nakano ◽  
...  
Keyword(s):  
Isolation System ◽  
Passive Isolation

Study of a Hybrid Vibration Isolator and Its Properties

2005 ◽  
Author(s):  
Shi-Jian Zhu ◽  
Xian-Jun Wu
Keyword(s):  
Transfer Function ◽  
Natural Frequency ◽  
High Frequency ◽  
Damping Ratio ◽  
Structural Vibration ◽  
Good Effect ◽  
High Frequency Range ◽  
Frequency Range ◽  
Isolation System ◽  
Passive Isolation

In order to isolate the structural vibration in high frequency range effectively, low damping ratio of the isolator is preferred in the high frequency range. While in order to constrain the peak response value near the natural frequency, high damping ratio is preferred. Damping ratio of a passive isolation system is constant with respect to frequency. It cannot fulfill such a conflict request. A novel hybrid isolator, which consists of a passive one and a force actuator, was brought out in this paper to achieve a varying damping ratio with respect to frequency. The force actuator detects the deformation of the isolator and generates actuating force according to a designed transfer function. The transfer function was designed to have the property of increasing the damping near the natural frequency of the suspension system and decreasing the damping ratio in the high frequency range. Two application examples were given and good effect was found.

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