scholarly journals Fully Pneumatic Semi-Active Vibration Isolator Design and Analysis

2017 ◽  
Author(s):  
Hans W. Schaeffer ◽  
Atul G. Kelkar
Keyword(s):  
Vibration Isolation ◽  
Relative Displacement ◽  
Complete Characterization ◽  
Effective Orifice Area ◽  
Vibration Isolator ◽  
Linear Quadratic ◽  
Ride Height ◽  
Isolation System ◽  
System A ◽  
Active Vibration

This paper presents a methodology of designing, modeling, and controlling a fully pneumatic semi-active vibration isolator system. The prototype vibration isolator system consists of an air spring, a variable orifice valve, and an accumulator which has the ability to simultaneously adjust the damping and natural frequency characteristics of the system. This paper presents a comprehensive work of modeling, hardware design, control design, and experimental validation of the proposed semi-active vibration isolation system. A higher fidelity model is obtained by complete characterization of nonlinear relationships between pressure versus volume and effective orifice area versus ride height. The performance of three semi-active controller designs — Linear Quadratic Impulse (LQI), Modified Skyhook, and Relative Displacement — is evaluated and compared experimentally using an OEM Peterbilt cabin suspension unit. The results demonstrate that the properly tuned semi-active suspension provides increased vibration isolation over the traditional passive cabin suspension design.

Development of Vibration Isolator With Controllable Stiffness Using Permanent Magnets and Coils

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Kai Meng ◽  
Yi Sun ◽  
Huayan Pu ◽  
Jun Luo ◽  
Shujin Yuan ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Vibration Isolation ◽  
Permanent Magnets ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stealth Technology ◽  
Active Vibration ◽  
Magnetic Rings

In this study, a novel vibration isolator is presented. The presented isolator possesses the controllable stiffness and can be employed in vibration isolation at a low-resonance frequency. The controllable stiffness of the isolator is obtained by manipulating the negative stiffness-based current in a system with a positive and a negative stiffness in parallel. By using an electromagnetic device consisting of permanent magnetic rings and coils, the designed isolator shows that the stiffness can be manipulated as needed and the operational stiffness range is large in vibration isolation. We experimentally demonstrate that the modeling of controllable stiffness and the approximation of the negative stiffness expressions are effective for controlling the resonance frequency and the transmissibility of the vibration isolation system, enhancing applications such as warship stealth technology, vehicles suspension system, and active vibration isolator.

Active Control for Power-Train Vibration of Automotive Using Active Mounts

2013 ◽  
Vol 330 ◽  
pp. 598-601
Author(s):  
Guo Chun Sun ◽  
Li Meng He
Keyword(s):  
Optimal Control ◽  
Vibration Isolation ◽  
Linear Quadratic Regulator ◽  
Active System ◽  
Linear Quadratic ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Engine Vibration ◽  
Active Vibration ◽  
Piezoelectric Stack Actuator

In this work, a new active mount featuring piezostack actuators and a rubber element is proposed and applied to a vibration control system. After describing the configuration and operating principle of the proposed mount, an appropriate rubber element and appropriate piezostacks are designed. Through the analysis of the property of the rubber and piezoelectric stack actuator, a mechanical model of the active vibration isolation system with the active mounts is established. An optimal control algorithm is presented for engine vibration isolation system. the controller is designed according to linear quadratic regulator (LQR) theory. Simulation shows the active system has a better consequence in reducing the vibration of the chassis significantly with respect to the ACM and the optimal control than that in the passive system.

scholarly journals Design and Experimentation of a Self-Sensing Actuator for Active Vibration Isolation System with Adjustable Anti-Resonance Frequency Controller

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1941
Author(s):  
Yuan Fu ◽  
Shusen Li ◽  
Jiuqing Liu ◽  
Bo Zhao
Keyword(s):  
Resonance Frequency ◽  
Vibration Isolation ◽  
Variable Frequency ◽  
Dynamic Vibration Absorber ◽  
Isolation System ◽  
Vibration Isolation System ◽  
System A ◽  
Absorber Structure ◽  
Active Vibration ◽  
Frequency Controller

The vibration isolation system is now indispensable to high-precision instruments and equipment, which can provide a low vibration environment to ensure performance. However, the disturbance with variable frequency poses a challenge to the vibration isolation system, resulting in precision reduction of dynamic modeling. This paper presents a velocity self-sensing method and experimental verification of a vibration isolation system. A self-sensing actuator is designed to isolate the vibration with varying frequencies according to the dynamic vibration absorber structure. The mechanical structure of the actuator is illustrated, and the dynamic model is derived. Then a self-sensing method is proposed to adjust the anti-resonance frequency of the system without velocity sensors, which can also reduce the complexity of the system and prevent the disturbance transmitting along the cables. The self-sensing controller is constructed to track the variable frequency of the disturbance. A prototype of the isolation system equipped with velocity sensors is developed for the experiment. The experiment results show that the closed-loop transmissibility is less than −5 dB in the whole frequency rand and is less than −40 dB around, adding anti-resonance frequency which can be adjusted from 0 Hz to initial anti-resonance frequency. The disturbance amplitude of the payload can be suppressed to 10%.

Active Vibration Isolation of Metrology Frames; A Modal Decoupled Control Design

2005 ◽  
Vol 127 (3) ◽  
pp. 223-233 ◽  
Author(s):  
Marcel Heertjes ◽  
Koen de Graaff ◽  
Jan-Gerard van der Toorn
Keyword(s):  
Vibration Isolation ◽  
Isolation System ◽  
Single Input Single Output ◽  
Single Output ◽  
System A ◽  
Active Vibration ◽  
Single Input ◽  
And Performance ◽  
Six Degree Of Freedom ◽  
Active Vibration Isolation

For a six degree-of-freedom active vibration isolation system, a control strategy based on modal decoupling is proposed. This has the advantage of controlling the modal directions on a centralized single-input single-output basis. As a consequence, stability and performance can be imposed in each of the modal directions separately. An experimental demonstration is given using a dummy metrology frame. That is, a 1600 kg payload mass supported by three combined pneumatic and Lorentz controlled isolators. With this setup, two unstable modal directions resulting from a high center of gravity are stabilized without compromising performance in any of the remaining directions. In fact, performance in the remaining directions is enhanced using manual loop shaping.

scholarly journals Electromagnetic and Mechanical Characteristics Analysis of a Flat-Type Vertical-Gap Passive Magnetic Levitation Vibration Isolator

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Baoquan Kou ◽  
Yiheng Zhou ◽  
Xiaobao Yang ◽  
Feng Xing ◽  
He Zhang
Keyword(s):  
Vibration Isolation ◽  
Mechanical Characteristics ◽  
Magnetic Levitation ◽  
Structural Parameters ◽  
Force Density ◽  
Vibration Isolator ◽  
Isolation System ◽  
Flat Type ◽  
Characteristics Analysis ◽  
Vertical Gap

In this paper, we describe a flat-type vertical-gap passive magnetic levitation vibration isolator (FVPMLVI) for active vibration isolation system (AVIS). A dual-stator scheme and a special stator magnet array are adopted in the proposed FVPMLVI, which has the effect of decreasing its natural frequency, and this enhances the vibration isolation capability of the FVPMLVI. The structure, operating principle, analytical model, and electromagnetic and mechanical characteristics of the FVPMLVI are investigated. The relationship between the force characteristics (levitation force, horizontal force, force ripple, and force density) and major structural parameters (width and thickness of stator and mover magnets) is analyzed by finite element method. The experiment result is in good agreement with the theoretical analysis.

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