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A high frequency vibration compensation approach for ultrahigh resolution SAR imaging based on sinusoidal frequency modulation Fourier-Bessel transform 被引量:1
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作者 CHEN Siyu WANG Yong CAO Rui 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第4期894-905,共12页
Ultrahigh resolution synthetic aperture radar(SAR)imaging for ship targets is significant in SAR imaging,but it suffers from high frequency vibration of the platform,which will induce defocus into SAR imaging results.... Ultrahigh resolution synthetic aperture radar(SAR)imaging for ship targets is significant in SAR imaging,but it suffers from high frequency vibration of the platform,which will induce defocus into SAR imaging results.In this paper,a novel compensation method based on the sinusoidal frequency modulation Fourier-Bessel transform(SFMFBT)is proposed,it can estimate the vibration errors,and the phase shift ambiguity can be avoided via extracting the time frequency ridge consequently.By constructing the corresponding compensation function and combined with the inverse SAR(ISAR)technique,well-focused imaging results can be obtained.The simulation imaging results of ship targets demonstrate the validity of the proposed approach. 展开更多
关键词 synthetic aperture radar(SAR) high frequency vibration compensation sinusoidal frequency modulation FourierBessel transform(SFMFBT)
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Vibration Compensation for Scanning Tunneling Microscope 被引量:1
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作者 LI Meng chao, FU Xing, WEI Xiao lei, HU Xiao tang (State Key Lab.of Precision Measurement Technology and Instrument, Tianjin University,Tianjin 300072, CHN) 《Semiconductor Photonics and Technology》 CAS 2003年第4期230-233,共4页
The influence of vibration is already one of main obstacles for improving the nano measuring accuracy.The techniques of anti-vibration,vibration isolation and vibration compensation become an important branch in nano ... The influence of vibration is already one of main obstacles for improving the nano measuring accuracy.The techniques of anti-vibration,vibration isolation and vibration compensation become an important branch in nano measuring field.Starting with the research of sensitivity to vibration of scanning tunneling microscope(STM),the theory,techniques and realization methods of nano vibration sensor based on tunnel effect are initially investigated,followed by developing the experimental devices.The experiments of the vibration detection and vibration compensation are carried out.The experimental results show that vibration sensor based on tunnel effect is characterized by high sensitivity,good frequency characteristic and the same vibratory response characteristic consistent with STM. 展开更多
关键词 Nano vibration sensor Scanning tunneling microscope(STM) Tunnel effect vibration compensation
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Bench Test of the Vibration Compensation Interferometer for EAST Tokamak
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作者 李恭顺 杨曜 +10 位作者 刘海庆 揭银先 邹志勇 王正兴 曾龙 魏学朝 李维明 兰婷 朱翔 刘煜锴 高翔 《Plasma Science and Technology》 SCIE EI CAS CSCD 2016年第2期206-210,共5页
A visible laser-based vibration compensation interferometer has recently been designed for the EAST tokamak and the bench test has been finished.The system was optimized for its installation on EAST.The value of the f... A visible laser-based vibration compensation interferometer has recently been designed for the EAST tokamak and the bench test has been finished.The system was optimized for its installation on EAST.The value of the final optical power before the detectors without plasma has been calculated from the component bench test result,which is quite close to the measured value.A nanometer level displacement(of the order of the laser's wavelength) has been clearly measured by a modulation of piezoelectric ceramic unit,proving the system's capability. 展开更多
关键词 vibration compensation system design tokamak diagnostic
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DOUBLE LOOP ACTIVE VIBRATION CONTROL OF PNEUMATIC ISOLATOR WITH TWO SEPARATE CHAMBERS
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作者 YANG Qingjun LI Jun WANG Zuwen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2006年第4期610-613,共4页
A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation: ① The low frequency resonance... A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation: ① The low frequency resonances introduced into the system; ② Conflict between lower isolation frequency and stiffness high enough to limit quasi-static stroke;③ Inconsistent isolation level with different force load. The design of two separate chambers is for the purpose of tuning support frequency and force independently and each chamber is controlled by a different valve. The inner one of double-loop structure is pressure control, and in order to obtain good performance, nonlinearities compensation and motion flow rate compensation (MFRC) are added besides the basic cascade compensation, and the influence of tube length is studied. The outer loop has two functions: one is to eliminate the resonance caused by isolation support and to broaden the isolation frequency band by payload velocity feedback and base velocity feed forward, and the other is to tune support force and support stiffness simultaneously and independently, which means the support force will have no effect on support stiffness. Theoretical analysis and experiment results show that the three drawbacks are overcome simultaneously. 展开更多
关键词 Pneumatic isolator Active vibration control Double-loop control Two separate chambers Mass flow rate compensation (MFRC)
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