Research On Autocollimatic Measurement System Of Area-array CCD

The autocollimator is a high accuracy instrument of small angle measurement, which plays an important role in verification of prismatic polyhedron and multitooth dividing table, measure linearity, planarity and relative angle measuring. So it is a essential instrument in the trade such as precise measurement and precise production.At present, most of the domestic autocollimaors are just competent for only one demensional angle with small measureing scope and low intelligence. With the development of science and technology, the higher precision demand in the trade of apparatus production is put forward to the technology of precise measurement. Moreover, the widely application of micro-electronics technology, sensor technology and computer technology in precise apparatus, has paved the way for researching high accuracy two-axis autocollimator.In the subject, CCD image sensor was employed as photoelectric transformer, A new model of two-axis autocollimator with high accuracy, wide measureing scope, and high intelligence were finished on the theory of autocollimatic measurement. The research work mainly include designation, installation, debug and final verification of mechanic structure, optical system, hardware sircuit and software system.In optical system, several high-powered LED was employed as array lighting source, the optical route is designed as pulldown type, so the size of instrument can be reduced.In hardware circuit, the speed of data processing are improved with DSP, Field programmable gate array(FPGA) control logic of periphery circuit.In software system, we analyze the principle of subpixel subdivision and establish the mathematic model. The software subdivision improve the measuring accuracy and resolution more greatly. The program was compiled with C language which possess good structure, readibility and transplantation. A lot of work has been done for the communication between operator and machine, the measureing interface is very friendly and guarantees the maneuverability of the instrument.We check over the performance and technology index of the model apparatus and make analysis for the error. The instrument has measuring range of ±300", measuring precision of 0.2" and resolution of 0.01".