Fiber Bragg Grating Load Cell Developed

Weighing sensors, the key units of many measurement systems, are widely used on a large-scale of applications in trade, machinery, food, metallurgy, mining, construction and other fields. At the present time, the majority of the weighing systems in both domestic and foreign product markets is based on traditional electrical sensors, which are with a long history and mature in technology .However, with the development of technology, more and more demanding requirement are brought out and the drawbacks of these traditional sensors such as being difficult to overcome the electromagnetic interference, corrosion and so on make developing new types of weighting sensors a critical issue.Fiber Bragg Grating sensor(FBGs), characterized by that the Bragg wavelength is sensitive to strain on it and the temperature, has developed into a important branch of optical fiber technologies since it was invented two decades ago. Due to special features of FBGs such as immune to environment electrical or magnetic interference, integrating sensing and transmitting in one device, simple structure and ease of use, it provides perspective approaches to greatly improve the safety, reliability and sensitivity of weighting systems.Based on the research status of load cell and the study of the need of domestic market, my research work during the master's program was focused on theoretical analyzing and experiments on weighing systems with advanced FBG(Fiber Bragg Grating) as the sensitive element. The main contents of this thesis include:1) Some key parameters of FBG are studied based on the Experiment with a system consisting of FBGs on uniform cantilever beam, which has simple theoretical model and displayed a good linear relationship between the loads the gratings' wavelength shifts.2) The mechanism characteristics of double holed cantilever beam are analyzed. A weighing system based on double holed cantilever beam with a maximum load of 100kg, is designed and fabricated. The experiment give a good result with 15.51 pm/kg sensitivity and 0.009% error. 3) Labview based software which integrated the data communication with optical time domain reflectometer, analysis FBGs wavelength shifts, calculating and load weighing and calibrating sensitivity is desgined.