Research On Some Technical Problems For Micro-Amplitude Angular Vibration Measurement By Laser Interferometry

Combined with the Innovation Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems of Zhejiang University "Research on Broadband and High Precision Angular Vibration Calibration Device",some technical problems for micro-amplitude angular vibration measurement by laser interferometry was researched.In chapter 1,the research background and significance of this thesis was introduced.First,the technology of laser interferometry measurement was introduced.Secondly,the research status of angular vibration measuring technology by laser interferometry at home and abroad was overviewed.At last,the research purpose and contents of this thesis were generalized.In chapter 2,the errors and their compensation technology for micro-amplitude angular vibration measurement by laser interferometry was studied.First,the principle of micro-amplitude angular vibration measurement by laser interferometry was presented.After that,the optical path error brought by cube-corner prism during measurement was analyzed,and the error compensation method was also proposed.In addition,the other error factors of angular vibration measurement system were studied including lateral error,cosine error and environmental error,etc.And the maximum permitted angular displacement was also deducted based on allowable error range.In chapter 3,the vibration waveform demodulation method based on a single laser interferometry signal was researched.First of all,the quadrature feature of two quadrature interferometry signals was studied,and the requirement of phase-shifting of a single interferometry signal was proposed.Furthermore,the phase-shifting method based on a single frequency sinusoidal signal was introduced.And then,the alternating phase-shifting method based on variable frequency and a single interferometry signal was researched,which included the algorithm of adaptive correction for phase alignment of the interferometry signals.Last but not least,vibration waveform was demodulated by two orthogonal laser interferometry signals.In chapter 4,the sinusoidal parameter identification method based on correlation filtering was researched.At first,the sine parameter identification principle of the correlation filtering was proposed based on the calculation process of the laser interferometry signal.At second,the realization method of correlation filtering was studied,while the effects of the correlation filtering method by sampling rate and distortion were also researched.At last,the program of calculation of vibration measurement signal based on correlation filtering by laser interferometry signals was designed.In chapter 5,the experimental research on the technical problems for micro-amplitude angular vibration measurement was introduced.On the one hand,the measurement of the amplitude and phase characteristics of angular acceleration sensor by use of two laser interferometry signals based on sine approximation method and a single laser interferometry signal based on phase-shifting method and correlation filtering method was researched respectively and compared.It is true that the vibration waveform was demodulated by software based on a single interferometry signal and the amplitude and phase characteristics of the angular acceleration sensor measured by the two methods were basically consistent.On the other hand,the optical path error of experimental data was compensated specifically.In chapter 6,the achievements of this thesis were summarized,and the following research work was prospected.