Development Of New PSD Photoelectric Autocollimator

The photoelectric autocollimator is a precision instrument that measures the change of the angle of the measured plane through the optical imaging system.Its measurement field of view and measurement accuracy are very important for the use of the instrument.This thesis aims at the problem that the measurement field of view and measurement accuracy of the traditional photoelectric autocollimator cannot be taken into consideration,and puts forward the scheme of using the position sensitive detector PSD as the photoelectric receiver device of the autocollimator,and aims at the nonlinear distortion of the receiver Carry out correction to achieve the purpose of expanding the measurement field of view and improving the measurement accuracy.In this thesis,based on the existing optical system,the system light source is selected and the light source drive circuit is designed;a multi-channel signal generator is designed to modulate the light source,and the sample and hold is used to filter the interference signal in the subsequent processing circuit.Effectively solve the effect of the background light and the dark current of PSD itself on the measurement accuracy during the actual measurement process;I/V conversion and amplification circuit,addition and subtraction operation circuit are designed according to the PSD displacement calculation formula,and pass through the data acquisition module Upload the output of the analog circuit to the computer to achieve data preprocessing and correction;for the problem of large measurement error between the actual measured position coordinate value and the ideal coordinate value caused by PSD photoelectric response distortion,The position coordinate correction algorithm is compared and analyzed,and finally the BP neural network algorithm is used to correct the position coordinate.Through system construction and experimental verification,the measurement field of view of this system is±1000",the system uncertainty is 0.7",and the resolution is 0.1".Experimental test results show that the design of the system is reasonable,the measurement range is wide,and the accuracy of the measurement results is high,and its various indicators basically meet the design requirements.