The Key Technology Research Of Torque Sensing Based On FBG

The main purpose of this project is developing a kind of large torque(20kNm) measurement system based on FBG which is suitable for the marine environment. At this stage, torque sensor with a small range(100Nm) was set up, which is used to predict the sensing properties of FBG, sensing network establishment, temperature drift and the key technologies of the dynamic performance. Torque measurement is widely applied in the ship, automobile, etc. Large torque measurement is the technological frontier in this field, especially in the harsh environment; torque measurement is one of the technical bottlenecks which are often needed to be overcome. Marine environment is very complex, which is always accompanied with severe vibration, strong electromagnetic interference, high temperature, high humidity and underwater environment, so FBG can play the role that other electrical sensors can't do. Considering the limitations of electrical sensors under the special environment such as high humidity, this project is proposed to study a kind of new system which is non-electric, suitable for the underwater environment. The key technology was researched and mastered. The main research content of this article is as follows:1. From the aspects of FBG sensing mechanism, torque measurement and temperature compensation principle. Established the mathematical model of FBG torque sensor and made a scheme of torque measurement experiment with FBG. 2. Established the static torque sensing system based on FBG, which includes the mechanical design of FBG torque sensor system; the design and simulation of sensitive element and the FBG demodulation system. Then taken a series of experiments on the specifications; degree of linearity; stability about the sensor system. What's more, installed a resistance strain gauge, which gets a result to make a comparison with the FBG system. By the result of the compare, the torque sensitivity of this sensing device is 22pm/Nm, the non-linearity error is less than 0.5‰, the repeatability error is less than 1‰ and has a good temperature compensation effect. 3. It mainly introduced WDM, SDM, TDM and mixed multiplexing technology of FBG, and described the advantages, disadvantages, applications of each technique. The scheme of FBG sensor network based on WDM and SDM is proposed, and FBG demodulator based on FBGA module has been designed and constructed. 4. It mainly introduced the application of optical interconnection technology in dynamic torque measurement, and the optical interconnection's effect on optical signal in fiber sensing network. Losses and changes of the optical signal by this technology in the optical signal chain are analyzed, and the influence on the central wavelength of FBG is detected; A dynamic torque measurement system using fiber optic rotary joint is designed for preliminary experimental study.