Research On Autocollimation 3D Angle Measurement Method Based On Grating Spectroscopic And Combined Target

As one of the key basic geometric quantities,the realization of high-precision measurement of angle is of great significance to scientific research and industrial applications.The angle measurement mainly includes the three-dimensional(3(D)angle measurement of the pitch angle,yaw angle and roll angle rotated around the coordinate axes X-axis,Y-axis and Z-axis.In practical engineering applications and scientific research,simultaneous measurement of 3D angle changes is required in many fields.For example,the Abbe error measurement of the coordinate measuring machine,the measurement of the attitude angle of the satellite payload,and the monitoring of the attitude and attitude of the missile launch all require high-precision measurement of the 3D angle at the same time.Therefore,there is an urgent need for a method that can achieve high-precision simultaneous measurement of 3D angle.Focusing on the requirement of simultaneous measurement of 3D angle,the traditional autocollimation method cannot achieve 3D angle measurement,and the3 D angle measurement method due to coupling errors leads to low measurement accuracy and mutual limitation of the 3D angle measurement range,this paper proposes "Research on autocollimation 3D angle measurement method based on grating spectroscopic and combined target",aiming to realize simultaneous measurement of 3D angles with high precision and independent measurement range.The main research contents of the paper are as follows:Aiming at the problem that the autocollimation method cannot realize the simultaneous measurement of 3D angle,a autocollimation 3D angle measurement method based on a transmission grating and a combined target is proposed.The method uses the grating diffraction characteristic to convert a single beam of collimated light into three beams of collimated light,and takes the three beams of collimated light as secondary collimated light,and converts the change of the angle to be measured into the propagation of the collimated beam by combining the target.The direction change,the direction change of the collimated beam is obtained by the photoelectric detection unit to realize the simultaneous measurement of 3D angle.Aiming at the problem that the 3D angle measurement model is too simplified,which leads to the influence of the coupling between angles on the measurement accuracy,a 3D angle geometric optical measurement model based on the principle of autocollimation is established by using the optical matrix transformation method,the model can completely describe the interaction mechanism between the angular coupling and the angular measurement.On this basis,a modified measurement model based on the continuous iterative method is proposed to reduce the influence of angular coupling on the measurement accuracy.Further,the study uses the optical magnification method to improve the measurement resolution of the roll angle to keep the 3D angle measurement resolution consistent.Aiming at the mutual limitation of angle measurement range in the 3D angle measurement method based on the principle of autocollimation,a tracking measurement method based on transmission grating and flexible deflection mechanism is proposed.In this method,the roll angle value of the combined target is used as a feedback signal,and the flexible deflection mechanism is controlled to make the transmission grating track the roll of the combined target.At this time,the effective surface element of the photodetector is only used to measure the yaw angle and pitch angle.The output angle value of the flexible deflection mechanism can be obtained,and the 3D angle measurement range can be independent by using this method,and the problem of mutual limitation of the angle measurement range can be solved.In addition,the method does not affect the angle measurement resolution of the system while increasing the angle measurement range,which provides a new way to improve the angle measurement range based on the principle of autocollimation.Aiming at the problem that the machining error of the combined target limits the further improvement of the measurement accuracy of the roll angle,a method for measuring the perpendicularity of the double reflection surface based on the transmission grating is proposed.The method firstly analyzes the influence mechanism of the combined target machining error(perpendicularity of the double reflector)on the roll angle measurement accuracy and establishes a roll angle measurement model including the combined target processing error.Then,the CMOS image sensor combined with the collimation method is used to measure the parallelism between the double beams,and the processing error of the combined target is calculated according to the parallelism of the double beams,which further improves the measurement accuracy of the roll angle.Finally,the designed experimental device for 3D angle measurement based on grating diffraction and the performance of its main components are tested,including the performance test of the angle generator,the effective resolution test of the photoelectric detection system,the performance test of the tracking measurement module,and the measurement of the machining error of the combined target.And the overall performance test of the 3D angle measurement system.The experimental results show that the 3D angle measurement resolution of the 3D angle measurement system reaches 0.010″,the 3D angle measurement range is independent of each other,both are 0～250″,and the expanded uncertainty of the yaw,pitch angle and the roll angle within 10″ is 0.060″,0.060″ and 0.110″(k=2).