scholarly journals A Novel Shock Absorber with the Preload and Global Negative Stiffness for Effective Shock Isolation

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Zecui Zeng ◽  
Lei Zhang ◽  
Ming Yan
Keyword(s):  
Permanent Magnet ◽  
Shock Absorber ◽  
Jacobian Matrix ◽  
Relative Displacement ◽  
Negative Stiffness ◽  
The Novel ◽  
Shock Test ◽  
Linear Spring ◽  
Shock Isolation ◽  
Isolation Performance

A novel shock absorber with the preload structure and global negative stiffness is proposed for the shock isolation of sensitive systems. The novel shock absorber is composed of a linear spring and permanent magnet sets. The preload force and negative stiffness region are related to the attractive force between permanent magnet sets. The aim of this paper is to investigate the shock isolation performance of the novel shock absorber. Firstly, a static analysis of the novel shock absorber is carried out. Secondly, the motion stability of the NSA is analyzed by the Jacobian Matrix and the shock response is calculated numerically compared with the conventional preload structures. Finally, the shock test of the novel shock absorber is completed to verify the above results. It is found that the novel shock absorber could be advantageous in improving shock isolation in terms of relative displacement and absolute acceleration compared with conventional preload structures.

Shock isolation characteristics of a bistable vibration isolator with tunable magnetic controlled stiffness

2021 ◽  
pp. 1-28
Author(s):  
Bo Yan ◽  
Peng Ling ◽  
Yanlin Zhou ◽  
Chuan-yu Wu ◽  
Wen-Ming Zhang
Keyword(s):  
Damping Ratio ◽  
Excitation Amplitude ◽  
Relative Displacement ◽  
Vibration Isolator ◽  
Maximum Acceleration ◽  
Vibration Isolators ◽  
Displacement Ratio ◽  
Shock Isolation ◽  
Maximum Relative Displacement ◽  
Isolation Performance

Abstract This paper investigates the shock isolation characteristics of an electromagnetic bistable vibration isolator (BVI) with tunable magnetic controlled stiffness. The theoretical model of the BVI is established. The maximum acceleration ratio (MAR), maximum absolute displacement ratio (MADR) and maximum relative displacement ratio (MRDR) are introduced to evaluate the shock isolation performance of the BVI. The kinetic and potential energy are observed to further explore the performance of the BVI. The effects of the potential barrier, shape of potential well, damping ratio on the BVI are discussed compared to the linear vibration isolators (LVI). The results demonstrate that the intrawell oscillations and snap-through oscillations are determined by the excitation amplitude and duration time of main pulse. MADR and MRDR of the BVI are smaller than those of the LVI. The maximum acceleration peak amplitude of the BVI is far below that of the LVI, especially when the snap-through oscillation occurs. In brief, the proposed BVI has a better shock isolation performance than the LVI and has the potential to suppress the shock of space structures during the launch and on-orbit deploying process.

scholarly journals Improving Low Frequency Isolation Performance of Optical Platforms Using Electromagnetic Active-Negative-Stiffness Method

2020 ◽  
Vol 10 (20) ◽  
pp. 7342
Author(s):  
Yamin Zhao ◽  
Junning Cui ◽  
Junchao Zhao ◽  
Xingyuan Bian ◽  
Limin Zou
Keyword(s):  
Root Mean Square ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Laser Interferometry ◽  
Relative Displacement ◽  
Negative Stiffness ◽  
Mean Square ◽  
Electromagnetic Actuators ◽  
Micro Vibration ◽  
Isolation Performance

To improve the low-frequency isolation performance of optical platforms, an electromagnetic active-negative-stiffness generator (EANSG) was proposed, using nano-resolution laser interferometry sensors to monitor the micro-vibration of an optical platform, and precision electromagnetic actuators integrated with a relative displacement feedback strategy to counteract the positive stiffness of pneumatic springs within a micro-vibration stroke, thereby producing high-static-low-dynamic stiffness characteristics. The effectiveness of the method was verified by both theoretical and experimental analyses. The experimental results show that the vertical natural frequency of the optical platform was reduced from 2.00 to 1.37 Hz, the root mean square of displacement was reduced from 1.28 to 0.69 μm, and the root mean square of velocity was reduced from 14.60 to 9.33 μm/s, proving that the proposed method can effectively enhance the low frequency isolation performance of optical platforms.

Non-resonant response of the novel airborne photoelectric quasi-zero stiffness platform with friction damping

2020 ◽  
Vol 64 (1-4) ◽  
pp. 315-324
Author(s):  
Guangxu Dong ◽  
Chicheng Ma ◽  
Feng Zhang ◽  
Yajun Luo ◽  
Chuanxing Bi
Keyword(s):  
Current Model ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Harmonic Balance Method ◽  
Negative Stiffness ◽  
The Novel ◽  
Friction Damping ◽  
Improve Measurement ◽  
Photoelectric System ◽  
Isolation Performance

To suppress the low frequency vibrations of airborne photoelectric system and improve measurement accuracy, a novel passive airborne photoelectric quasi-zero stiffness platform (APQZSP), which is composed of upper/bottom planes, anti-shaking structure and six quasi-zero stiffness (QZS) legs, is designed. The QZS leg is constructed by connecting the folded beam spring with magnetic negative stiffness spring (MNSS) in parallel. According to current model, the magnetic force and negative stiffness of MNSS are derived. As the friction damping is introduced with anti-shaking structure, the isolation performance of the platform under friction damping is investigated based on harmonic balance method. Then the effect of damping and excitation on the isolation performance is analyzed. The results indicate that with the QZS technology, the resonant frequency of the platform is reduced and the low frequency vibrations can be effectively isolated with APQZSP. Moreover, the friction damping can maintain the displacement transmissibility at unity as long as the excitation frequency is lower than the break-loose frequency, and then the resonance can be avoided.

Optimal Stator Design to Improve the Output Voltage of the Novel Three-Phase Doubly Salient Permanent Magnet Generator

2020 ◽  
Vol 8 (4) ◽  
pp. 118
Author(s):  
Vannakone Lounthavong ◽  
Warat Sriwannarat ◽  
Pattasad Seangwong ◽  
Apirat Siritaratiwat ◽  
Pirat Khunkitti
Keyword(s):  
Permanent Magnet ◽  
Output Voltage ◽  
The Novel ◽  
Three Phase ◽  
Doubly Salient ◽  
Stator Design ◽  
Permanent Magnet Generator

Electromagnetic performance and thermal analysis of a novel permanent magnet fluxed-switching coupler

2021 ◽  
pp. 1-18
Author(s):  
Lezhi Ye ◽  
Yulong Zhang ◽  
Mingguang Cao
Keyword(s):  
Temperature Distribution ◽  
Permanent Magnet ◽  
Permanent Magnets ◽  
Three Dimensional ◽  
Load Condition ◽  
Maximum Load ◽  
Maximum Temperature ◽  
The Novel ◽  
Transient Field ◽  
Three Dimensional Finite Element

To solve the problem of complex operating device and permanent magnets (PMs) demagnetization at high temperature, a new type of permanent magnet fluxed-switching coupler (PMC) with synchronous rotating adjuster is proposed. Its torque can be adjusted by rotating a switched flux angle between the adjuster and PMs along the circumferential direction. The structural feature and working principle of the PMC are introduced. The analytical model of the novel PMC was established. The torque curves are calculated in transient field by using the three-dimensional finite element method (3-D FEM). The temperature distribution of the novel PMC under rated condition is calculated by 3-D FEM, and the temperature distribution of the PM is compared with that of the conventional PMC. The simulation and test results show that the maximum temperature of copper disc and PM of the novel PMC are 100 °C and 48 °C respectively. The novel PMC can work stably for a long time under the maximum load condition.

The electronic structure of the novel rare-earth permanent magnet Sm2Fe17N3

1993 ◽  
Vol 5 (37) ◽  
pp. 6911-6924 ◽  
Author(s):  
B I Min ◽  
J -S Kang ◽  
J H Hong ◽  
S W Jung ◽  
J I Jeong ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Rare Earth ◽  
Permanent Magnet ◽  
The Novel

Sensor-less control of a novel axial flux-switching permanent-magnet motor

2018 ◽  
Vol 37 (6) ◽  
pp. 2299-2312
Author(s):  
Javad Rahmani Fard ◽  
Mohammad Ardebili
Keyword(s):  
Kalman Filter ◽  
Permanent Magnet ◽  
Extended Kalman Filter ◽  
Current Sensor ◽  
The Novel ◽  
Permanent Magnet Motor ◽  
Axial Flux ◽  
Content Type ◽  
Stator Current ◽  
Current Sensors

Purpose The purpose of this paper is to suggest a novel current sensor-less drive system for a novel axial flux-switching permanent-magnet motor drive to reduce the costs and avoid problems caused by faults of the current sensors. Design/methodology/approach Commonly, a conventional controller needs at least two current sensors; in this paper, the current sensors are removed by replacing estimated stator current with the extended Kalman filter. Findings A prototype of the novel axial flux-switching permanent-magnet motor is fabricated and tested. It is found that the experimental results confirm the proposed method and show that the control has almost the same performance and ability as the conventional control. Originality/value The axial flux-switching permanent-magnet motor is one of the most efficient motors, but current sensor-less control of an axial flux-switching permanent-magnet motor with a sandwiched permanent magnet and a unity displacement winding factor has not been specially reported to date. Thus, in this paper, the authors report on current sensor-less control based on the extended Kalman filter for electric vehicles.

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