M. S. Thesis Abstract

Design of a Tactile Sensor Based on Microbending Effects in Fiber Optics

John Winger

September 1987


Sensory feedback will be necessary in the next generation of robots if true flexible automation is to be achieved. One form of sensory feedback is tactile sensing. Tactile sensing, or taction, is the continuously variable sensing of forces and force gradients over an area. By using information obtained through taction, a robot could conceivably perform such tasks as part identification, assembly and bin picking. Research in tactile sensing has produced many different methods of performing taction. Problems such as hysteresis, limited range and sensitivity, and high cost have victimized many of these approaches. Therefore, the possibility of constructing a tactile sensor based on micro-bending losses in fiber optics was investigated. A prototype was built which was demonstrated to have a range of 0 to 300 grams, a sensitivity of 5 grams, a time constant no large than 0.14 seconds, and a spatial resolution of 0.05 inches. Furthermore, it was shown that a sensor based on bending losses in optimal fibers has the potential for much miniaturization, large forcel densities, and low costs. Problems encountered include some hysteresis and plastic deformations of the fibers cladding for large deflections.