Research On Optical Fiber Tactile Sensor

At present, minimally invasive surgery become more and more popular in people because of the risk is small, the small trauma to the surrounding tissue, rapid recovery of health and other advantages. Especially, nuclear magnetic resonance imaging technology, which is not with ionizing radiation, introduced in clinical devices and get more welcomed by surgeons and patients.In minimally invasive surgery, real-time tactile feedback from the interaction between the surgical instruments and tissues is essential to the surgeons. According to the real-time information, the surgeons can implement a more rational surgery program. Thus, development of optical fiber tactile sensor with Magnetic Resonance Imaging (MRI) compatible is so important. While, optical fibers are immune to electromagnetic interferences and this characteristic allows them to be MRI compatible. And it has low prices. Therefore, development of optical fiber tactile sensor will make the sensor in medical applications has been farther expanded. This paper, based on Extrinsic Fabry-Perot (F-P) Interf erometric (EFPI) principle and fiber Bragg grating (FBG) principle, two types of optical fiber tactile sensors are designed. The main content is as follows:1. F-P interferometric principle and FBG sensing principle are elaborated. Strain sensing principle of FBG is analyzed. When FBG is subjected to stress, the role of the axial stress is only considered, while the tangential stress is ignored.2. Two types of optical fiber F-P tactile sensors with a higher measuring range and with a higher sensitivity are researched respectively. And repeatability, hysteresis and resolution are measured, experimental results are in mainly agreements with the theoretical results. The optical fiber F-P tactile sensor with a higher measuring range, its measurement range is3N, sensitivity is0.23um/N, and resolution is0.2nm. While, the sensor with higher sensitivity, its measuring range is0.6N, sensitivity is2.02um/N and resolution is0.3nm. The results show that the two types of optical fiber tactile sensors have better performance indicators that can be used in different occasions.3. FBG tactile sensor is researched. Experimental and theoretical data is analyzed; results show that they are in a good agreement. In the range of5.8N, the central reflected wavelength of the FBG tactile sensor has a change of0.286nm. Therefore, the sensitivity is 0.0491nm/N. The linear fit of the multiple measurement results are higher than0.99, this indicate that the sensor has excellent repeatability.