An hourglass-type electromagnetic isolator with negative resistance electromagnetic shunt circuit

2020 ◽  
Vol 64 (1-4) ◽  
pp. 549-556
Author(s):  
Yajun Luo ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
Xinong Zhang
Keyword(s):  
Vibration Isolation ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Negative Resistance ◽  
Isolation System ◽  
Amplitude Vibration ◽  
Vibration Responses ◽  
The Stability ◽  
Isolation Performance ◽  
Shunt Circuit

The present work proposed an hourglass-type electromagnetic isolator with negative resistance (NR) shunt circuit to achieve the effective suppression of the micro-amplitude vibration response in various advanced instruments and equipment. By innovatively design of combining the displacement amplifier and the NR electromagnetic shunt circuit, the current new type of vibration isolator not only can effectively solve the problem of micro-amplitude vibration control, but also has significant electromechanical coupling effect, to obtain excellent vibration isolation performance. The design of the isolator and motion relationship is presented firstly. The electromechanical coupling dynamic model of the isolator is also given. Moreover, the optimal design of the NR electromagnetic shunt circuit and the stability analysis of the vibration isolation system are carried out. Finally, the simulation results about the transfer function and vibration responses demonstrated that the isolator has a significant isolation performance.

The Research on Robust LQ Control Applied to Uncertain Vibration Isolation System

2010 ◽  
Vol 34-35 ◽  
pp. 1289-1293
Author(s):  
Qiang Hong Zeng ◽  
Qi Wei He ◽  
Jing Jun Lou
Keyword(s):  
Optimal Control ◽  
Transfer Function ◽  
Vibration Isolation ◽  
Multi Objective Optimization ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Robust Optimal Control ◽  
Result Show ◽  
Isolation Performance ◽  
Lq Control

Synthesized considering several performance target, robust optimal control was applied to uncertain double layer vibration isolation system then the transfer function was got between input disturbance and out performance. By analyzing the amplitude-frequency characteristics of transfer function, the result show that the robust LQ control can successfully improve the isolation performance of uncertain hybrid vibration isolation system, realize the multi-objective optimization.

scholarly journals Experimental Validation of Fly-Wheel Passive Launch and On-Orbit Vibration Isolation System by Using a Superelastic SMA Mesh Washer Isolator

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Seong-Cheol Kwon ◽  
Mun-Shin Jo ◽  
Hyun-Ung Oh
Keyword(s):  
Vibration Isolation ◽  
Application Form ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Static Tests ◽  
Resolution Observation ◽  
Passive Vibration Isolation ◽  
Basic Characteristics ◽  
Vibration Isolation Performance ◽  
Isolation Performance

On-board appendages with mechanical moving parts for satellites produce undesirable micro-jitters during their on-orbit operation. These micro-jitters may seriously affect the image quality from high-resolution observation satellites. A new application form of a passive vibration isolation system was proposed and investigated using a pseudoelastic SMA mesh washer. This system guarantees vibration isolation performance in a launch environment while effectively isolating the micro-disturbances from the on-orbit operation of jitter source. The main feature of the isolator proposed in this study is the use of a ring-type mesh washer as the main axis to support the micro-jitter source. This feature contrasts with conventional applications of the mesh washers where vibration damping is effective only in the thickness direction of the mesh washer. In this study, the basic characteristics of the SMA mesh washer isolator in each axis were measured in static tests. The effectiveness of the design for the new application form of the SMA mesh washer proposed in this study was demonstrated through both launch environment vibration test at qualification level and micro-jitter measurement test which corresponds to on-orbit condition.

scholarly journals High-Efficiency Vibration Isolation for a Three-Phase Power Transformer by a Quasi-Zero-Stiffness Isolator

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hao Cao ◽  
Yaopeng Chang ◽  
Jiaxi Zhou ◽  
Xuhui Zhao ◽  
Ling Lu ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
High Efficiency ◽  
Power Transformer ◽  
Dynamic Stiffness ◽  
Harmonic Balance Method ◽  
Isolation System ◽  
Three Phase ◽  
Engineering Practices ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vibrations generated by a three-phase power transformer reduce the comfort of residents and the service life of surrounding equipment. To resolve this tough issue, a quasi-zero-stiffness (QZS) isolator for the transformer is proposed. This paper is devoted to developing a QZS isolator in a simple way for engineering practices. The vertical springs are used to support the heavy weight of the transformer, while the oblique springs are employed to fulfill negative stiffness to neutralize the positive stiffness of the vertical spring. Hence, a combination of the vertical and oblique spring can yield high static but low dynamic stiffness, and the vibration isolation efficiency can be improved substantially. The dynamic analysis for the QZS vibration isolation system is conducted by the harmonic balance method, and the vibration isolation performance is estimated. Finally, the prototype of the QZS isolator is manufactured, and then the vibration isolation performance is tested comparing with the linear isolator under real power loading conditions. The experimental results show that the QZS isolator prominently outperforms the existing linear isolator. This is the first time to devise a QZS isolator for three-phase power transformers with heavy payloads in engineering practices.

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.

scholarly journals Onset and stabilization of delay-induced instabilities in piezoelectric digital vibration absorbers

2022 ◽  
pp. 1045389X2110722
Author(s):  
Ghislain Raze ◽  
Jennifer Dietrich ◽  
Gaetan Kerschen
Keyword(s):  
Electromechanical Coupling ◽  
Sampling Period ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Sampling Procedure ◽  
Simple Modification ◽  
Piezoelectric Structure ◽  
Modification Procedure ◽  
The Stability ◽  
Shunt Circuit

The stability of a piezoelectric structure controlled by a digital vibration absorber emulating a shunt circuit is investigated in this work. The formalism of feedback control theory is used to demonstrate that systems with a low electromechanical coupling are prone to delay-induced instabilities entailed by the sampling procedure of the digital unit. An explicit relation is derived between the effective electromechanical coupling factor and the maximum sampling period guaranteeing a stable controlled system. Since this sampling period may be impractically small, a simple modification procedure of the emulated admittance of the shunt circuit is proposed in order to counteract the effect of delays by anticipation. The theoretical developments are experimentally validated on a clamped-free piezoelectric beam.

On an Improvement of Hybrid Vibration Isolation System

1997 ◽  
Author(s):  
Kazuki Mizutani ◽  
Yoshitaka Fujita ◽  
Ryojun Ikeura
Keyword(s):  
Hybrid System ◽  
Vibration Isolation ◽  
Control Method ◽  
Weighting Function ◽  
Phase Lag ◽  
Frequency Range ◽  
Active System ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Isolation Performance

Abstract This paper proposes a hybrid-type vibration isolation system controlled by a phase compensated LQ control method with a frequency shaped weighting function. The hybrid system is composed of a passive spring-damper system reducing vibrations of high frequency range and an active one reducing those of low frequency range. This system is controlled by the phase compensated digital LQ optimization method with a frequency shaped weighting function. By the proposed method, the phase-lag of the control system is compensated so that the vibration isolation performance is improved. Simulations for the active system are carried out and the effectiveness of the phase compensation is shown. Then, experiments for the hybrid system are carried out for sinusoidal or random excitations. It is confirmed that the purposed hybrid system has the excellent isolation performance for excited vibrations over the wide frequency range.

Vibration Isolation of Precision Payloads for Aerial Vehicles Using Magnetorheological Isolators

2005 ◽  
Author(s):  
Young-Tai Choi ◽  
Mikel Brigley ◽  
Norman M. Wereley
Keyword(s):  
Vibration Isolation ◽  
Control Input ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Aerial Vehicles ◽  
Lqg Control ◽  
Field Control ◽  
Aerial Vehicle ◽  
Vibration Isolation Performance ◽  
Isolation Performance

This study addresses the application of MR (magnetorheological) isolators to vibration isolation of precision payloads for aerial vehicles. To this end, a precision payload in an aerial vehicle is modeled as a six-degree-of-freedom (DOF) lumped parameter model of a sensor assembly. An MR isolator is modeled as a 3-DOF passive spring-damping element and a 3-DOF semi-active yield force due to the yield stress of an MR fluid. Three MR isolators are configured with equal installation angles between the precision payload and the base structure in the aerial vehicle. The governing equations of motion for the MR vibration isolation system of the precision payload for the aerial vehicle are derived and then key parameters of the MR isolators, such as stiffness, damping, and isolator orientation, are determined via a global optimization method. The simulated response of the passive MR vibration isolation system with no magnetic field control input and constant magnetic field control input are presented and analyzed under different excitation conditions. To improve the passive MR vibration isolation performance, a linear quadratic Gaussian (LQG) control algorithm is designed. Finally, simulated responses of the semi-active MR vibration isolation performance using LQG control are evaluated and compared with those of passive (zero or constant field) MR vibration isolation systems.

Vibration Isolation and Chaotic Vibration

2003 ◽  
Author(s):  
Rong-Jun Jiang ◽  
Shi-Jian Zhu
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Isolation ◽  
Harmonic Excitation ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Chaotic Vibration ◽  
Vibration State ◽  
Vibration Isolation Performance ◽  
Isolation Performance ◽  
Better Than

Taking single degree of freedom vibration isolation system under simple harmonic excitation as an example, and considering the energy, the vibration isolation performance in different conditions was studied theoretically and numerically. The results shows that when the simple harmonic excitation import energy is definite, the vibration isolation performance at the primary harmonic frequency of the nonlinear vibration isolation system is better than that of the linear system, and the vibration isolation performance of the nonlinear vibration isolation system in chaotic vibration state is much better than that in non-chaotic vibration state. For the same isolated object, if can let the vibration isolation system vibrate chaotically, the system will possess the best isolation performance at the primary frequency.

scholarly journals Dynamics and control of a bio-inspired Stewart platform

2021 ◽  
Vol 39 (2) ◽  
pp. 258-266
Author(s):  
Yuansheng Peng ◽  
Honghua Dai ◽  
Hao Zhang ◽  
Xiaokui Yue
Keyword(s):  
Dynamic Model ◽  
Feedback Linearization ◽  
Vibration Isolation ◽  
Control Method ◽  
Stewart Platform ◽  
The Novel ◽  
Isolation System ◽  
Theoretical Simulation ◽  
Vibration Isolation Performance ◽  
Isolation Performance

Collision and strong impacts take place in mission of the on orbit capture of non-cooperative spacecraft. So, it is necessary to design a vibration isolation system with efficient vibration isolation performance. A Stewart vibration isolation platform based on the bio-inspired isolation system is proposed in this paper. The characteristics of the novel bio-inspired Stewart platform realizes the vibration isolation protection of the serving spacecraft during the capture mission. The dynamic model of the vibration isolation platform is established by Lagrange's equations. The fidelity of the established dynamic model is verified via a comparison of the theoretical simulation and the ADAMS simulation. Comparisons between the presently proposed vibration isolation platform and the traditional spring-mass-damper type Stewart vibration isolation platform demonstrates the advantages of the present platform. The effects of system parameters on the isolation performance of the present platform are thoroughly investigated. The feedback linearization control method is used to control the present platform which overcomes the drift motion that occurs in the passive isolation case. The results show that the novel bio-inspired Stewart platform has excellent vibration isolation performance, which provides a promising way for the vibration isolation of the non-orbit capture mission.

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