The Study On Fiber Grating Dynamic Weighing System

At present, the vehicle overloads of our country is extremely common, in some area, nearly all vehicles exist overloading of varying degrees. So that it becomes more and more important to reinforce control over road transportation. The important means to efectively restrain overloads is to charge by weight, and the key technology of charging by weight is weight in motion, the study of dynamic weighing technology is of economic significance and social value in assurance of appropriate use of the roads.Nowadays, with the development of intelligent materials, especially the fiber sensor represented by fiber grating, it provides new approaches and prosperous future for the research of weighing system. So we select fiber grating as the sense organ for the researching of the vehicle weigh-in-motion system. First of all, this paper introduces FBG's structure, principle, making methods, its application and the research situation in the world. Then analysis FBG sensor's characters about strain and temperature. On the basis of principle research on fiber grating match, matched demodulation method of fiber grating based on microcontroller is put forward with practice. And the demodulation experimental system is built.The hardware of this WIM system is mainly made up of four parts: optic fiber sensor, analog circuit, digital circuit and the communication transmission. The first part consists of lamp-house, interferometer, PIN detector; the second part consists of the band-pass filter, amplifier circuit of analog signal. Digital circuitis based on DSP, figure responsible for the acquisition, data processing and communications eth; communication transmissions use the HPI, through its transmission and computer. This paper makes software easy to update by adopting modularization idea to design software and makes system operation simple for friendly man-machine interface.Finally, this paper makes performance test and error analysis for the detecting system. The experiment indicates this kind of weighing system shows the features of simplicity, convenience, high precision, good durability, low cost and so on, which shows good prospect in future.