Research On Laser Velocity Measurement System Based On Correlation Measurement Technology

Currently, non-contact measurement is an important subject in mechanical measurements. With the rapid development of industry and technology, it is becoming increasingly important to realize and utilize the non-contact measurement principle and method, which is widely used in industry domain. There are many requirements for solid surface movement measurement in industrial production, measurement and other related domain. This paper is to research the velocity of steel, on the conveyor belt, in iron and steel industry where it uses non-contact measurement method.Starting with measuring the velocity of solid surface movement, using the method of non-contact measurement, the second-correlation measurement techniques are taken to detect the surface movement. For the purpose of being precise and real-time in the non-contact measurement, a laser velocity measurement system based upon correlation measurement technique is researched in this paper.Firstly, this paper, based on reference to domestic and foreign documents, summarizes the development of history and the present situation, and discusses its basic principle, detection method and research achievements in detail. Meanwhile, analyzing the application of the conditions for more mature non-contact movement measurement, appropriate correlation measurement technology, which is easily achievable and has the low cost of optical path, is selected in this paper. According to the correlation measurement technology for the requirements of optical structure, the selection standard for relative devices and how to design a laser transmission and reception system are discussed in this paper.Secondly, by analyzing the characteristic signal of the surface velocity, a mathematical model for correlation speed measurement is built, the principle of correlation speed measurement is specified, and transit time, an important parameter, is elicited. Next, the correlation measurement method for transit time is analyzed. Because the measurement, for transit time, using first-correlation algorithm, is not accurate in high noise intensity, the second-correlation algorithm is introduced and the feasibility of the theory is validated by experiments.Finally, by analyzing and designing signal acquisition module, signal noise processing module (sliding average processing, power frequency noise signal processing, random interference signal processing), signal second-correlation calculation module and peak detection module, correlation speed measurement system is established by NI Corporation's LabVIEW platform and the correctness of the system is validated by simulating results.