Research On A New Non-Contact Laser Tracking Detector Based On CMM

With the development of modern industry, free-form surfaces are widely used in aviation and space flight, automobile and impeller machines. Since the higher quality of free-form surfaces are required, so it is very important to measure the free-from surface accurately and quickly. At present, the most popular equipment used in free-form surfaces measurement is Three-coordinate measurement machine (CMM). CMM use the special detector to take measurement. So the CMM's function , precision and working efficiency is closely related to it's detector. The development of the CMM promotes the development of the detector, while the appearance of new type of detector expands the range of CMM's application. With the development of modern measurement technology, it is necessary to develop all kinds of new type of non-contact detector.Based on the formerly theory and practice of our laboratory, this paper presents a principle of half-light-spot imaging tracking, and develops a new type of optical non-contact tracking detector. This paper involves many principles such as precisionmachine, optics, electronics technology and autocontrol etc. Tracking signal is obtained by using the principle This signal is acquired by high precision Dual-element photodiode, and then conditioned by special differential circuit. Closed loop control is employed to adjust the intensity of laser in order to measure the different surface automatically.At the same time the theory is analyzed, large numbers of experiments is completed and plenty of data obtained. The tracking disciplinarian of a object with different characteristics , such as roughness, reflectivity, curvature and color, has been investigated on the three coordinate measuring system, further more the zero-drift disciplinarian is explored and improved. The track measurement in our research has higher resolving power and higher measure precision. Finally the reasons which affect the measurement precision are analyzed detailedly and the improved measures are put forward so as to establish the base to make this research to perfect.