Study On Optic Fiber Sensor Based On A Differentiating Interferometer In Measurement Of Rolling Force

There are two kinds of method to measure the rolling force: stress measure and sensor measure. Because it is difficult to find the center section and the force condition of four upright pillars is different, this method causes error sometimes. The measuring sensor is divided into the capacitance sensor, the pressure-magnetism and the resistance-strain sensor. The latter is popular, but its accuracy is easily disturbed by the factor electromagnetism, temperature and so on. A fiber-optic strain sensor based on a differentiating Sagnac interferometer is demonstrated to measure the rolling force by measuring strain of the elasticity element inside the rolling machine. The system is simple in structure and possesses high accuracy, super sensitivity. It is easy to be installed and used.The system consists of the sensor header, light path, pre-amplify, signal process circuit. The first sensitive part is the elasticity element installed inside the rolling machine whose strain is transformed into that of the optical fiber. The modulating principle and the rule to select the element is described. The formulas of sensor header is derived. Phase detect need a fiber-optic strain sensor based on a differentiating Sagnac interferometer. Structure of system is designed. The sensor can compress phase till hundreds of times and extends the range of dynamic measurement. The formulas of light path is presented. For detecting of light power, the pre-amplify, filtrating wave and integration circuit is designed.After the design of system and selection of element are completed, PZT is out of shape instead of the elasticity element in experiment. The result shows that the system designed in the article is correct. High accuracy at 0.18%, super sensitivity at 0.15V/ has been achieved. The system is used to measure other varying strain with good immunity of surrounding perturbation.