Study On Fiber Optic Sensing Non-contact Correlation Length Measurement Technology For Casting Steel

In continuous casting steel production process, the length measurement online and fix-length cutting is very important. Nowadays, most system adopted contact measurement method. Because of the formidable applied environment, the contact measurement equipment is hard to maintain and the precision is not promised for the abrasion. In this paper a new method of non-contact correlation length measurement with fiber optic sensor is researched in order to realizing online length measuring of casting steel.First, the theory of correlation measurement is discussed. Correlation measurement method utilizes random noise coming from target. It has good ability to resist interference, and applied well in formidable environment. Combining correlation measurement and optimized searching method, some physical parameters is easy to measure. Following, application and development of correlation measurement is introduced.In recent years, the technology of fiber optic sensor brings more attention. Because of the virtue of fiber sensor it has been extensively used. So in this paper, the theory of fiber optic temperature sensor is discussed and a new temperature sensor is introduced.To measuring length of casting steel online, we researched a new method , which can non-contact measure length in bad environment without affecting precision because of gliding. The method uses two sensors to sense temperature of casting steel, and correlates the data to work out lag time, then calculates the speed and length of steel.Correlation length measurement system includes fiber optic temperature sensor, photoelectric convertor, data collector and correlation program. The sensorsenses the temperature of steel. For special application, we use predigested fiber optic temperature sensors. Converter detects the optic signal from fiber and convert it into voltage signal which is digitalized. Then computer correlates the digital signals. Correlation program is the key portion of this system, it compares the similitude of two signal sequences and calculate the delay time between signals. Then the speed and length of steel is worked out. This paper discussed the real-time correlation algorithm and designed feasible program.