Research On A Novel Digital Shearing Speckle Interferometry Three-degree-of-freedom Angular Motion Measurement Metho

In machine tools and coordinate measuring machines,linear guide rail and rotary axis are the main precision motion units in the structure,and the detection of angular motion with three degrees of freedom is the key to realize precision machining and manufacturing.Most of the existing optical measurement methods need to install light source,detector or cooperative target mirror on the measured object,so the measurement errors introduced by cooperative target installation cannot be avoided.Digital speckle interferometry and digital shearography,as optical measurement methods without target mirror,have certain technical advantages in the measurement of angular motion of rigid body with three degrees of freedom.Among them,the angular motion measurement method based on digital speckle interferometry can realize the three-degree-of-freedom angular motion measurement simultaneously with high precision,but the system anti-interference performance needs to be improved.The linear digital shearography angle motion measurement method has strong anti-interference performance,but its measurement resolution will be limited by the amount of shear.Therefore,this thesis proposes inversion digital shearography three-degree-of-freedom angular motion simultaneous measurement method and reversal digital shearography threedegree-of-freedom angular motion measurement method.The shear device of these two measurement methods can realize the inverse or reverse of the image,thus increasing the shear amount and greatly improving the measurement resolution.They have the advantages of simple structure,strong anti-interference,fast measurement speed and high resolution,which can meet the requirements of rigid body degree of freedom angular motion measurement in industrial field environment.The main research work and innovation of this thesis are as follows:Firstly,a novel three-degree-of-freedom angular motion simultaneous measurement method based on inversion digital shearography is proposed.By studying the fringe formation mechanism in the three-degree-of-freedom angular motion detection process under the dual-beam inversion digital shearography optical setup,the relationship between pitch Angle,yaw Angle,roll Angle and interference phase distribution is established,and then the mathematical model of three-axis angular motion simultaneous measurement is proposed.Combined with the measurement model,the characteristics of phase fringe distribution are analyzed,and a series of verification experiments are carried out to verify the stability of the method and realize the simultaneous measurement of angular motion with three degrees of freedom.Finally,the source of measurement error is studied,the high measurement resolution of the method is verified,and the point selection strategy is clarified.Secondly,A novel three-degree-of-freedom angular motion measurement method based on reversal digital shearography is proposed,and its optical path structure and measuring principle are expounded.A simplified optical path for measuring pitch/yaw Angle is proposed,and the method is verified by experiments.Thirdly,a three-degree-of-freedom angular motion measurement method based on linear digital shearography is proposed.The sensitive mechanism of linear digital shearography to three-degree-of-freedom angular motion is analyzed,and the principle of roll Angle measurement is studied.The pitch Angle/yaw Angle measurement model based on linear digital shearography is proposed,and its measurement resolution is analyzed.Fourthly,the digital speckle interferometry three-degree-of-freedom angular motion simultaneous measurement method is studied,its performance is evaluated and an improvement plan is proposed.Accuracy calibration experiments are added and error compensation is performed on the measurement results.The optical path is integrated and instrumented,and a three-dimensional space carrier digital speckle interferometer for threedimensional micro-deformation and angle measurement is developed.