Fiber optic nerve systems for materials and structures that can feel pain

K. Hotate
2008 Micro Electro Mechanical Systems (MEMS), Proceedings of the IEEE International Conference on  
When we touch something sharp, we feel pain and jerk away our hand. Thanks to this sensation, we can protect our bodies from injury. There are millions of pain sensors called pain spots on a human body. These sensors are receptors consisting of sensory nerve cells, from which the sense of pain is transmitted to the brain via the nerve network. In addition to pain spots, there are many sensors on the body to protect us, such as cool spots, warm spots, pressure spots, and touch spots. The theme
more » ... spots. The theme of this paper is to deploy a "nerve network" on structures and materials such as bridges, bridge piers, pipelines for oil and natural gas, large-scale plants, and aircraft wings, in order to provide them with "pain" sensing capability. Various human sensors for strain, pressure, and temperature have been technologically emulated, and implemented as small, precise sensors using MEMS technology. However, it is not so easy to place a large number of these sensors on structures or materials in order to build a "nerve network". Since each sensor needs at least two lead wires, a huge number of lead wires must be managed for configuring a nerve network. Recently, research on nerve networks requiring no lead wires has been active, aiming at wireless communications between sensors by using integrated circuit technology. Its challenges include development of a means to supply power to sensors, and an extremely low power communication technology. This paper describes the fiber optic technology for a nerve network. A multipoint type fiber optic sensing system is currently being developed. In this system, many sensors equivalent to pain spots or heat spots are embedded in an optical fiber in the longitudinal direction, and information from multiple sensors can be obtained by using only one light source and one photodetector. If physical phenomena at each point of an optical fiber can be used for sensing, the whole optical fiber will be able to function as a sensor. Combined with technology that can acquire the positional information along the optical fiber, it becomes a nerve network. This type of sensor system is called a "distributed fiber optic sensing system". Whichever technology is applied, the system can eliminate the problem of a huge number of lead wires.
doi:10.1109/memsys.2008.4443602 fatcat:mszwuih5qvd27p3g5bxmdogepe