Experimental investigation of a tactile sensor based on bending losses in fiber optics

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. Problems such as hysteresis, limited range and sensitivity, and high cost have victimized many of past approaches to taction. Therefore, this paper presents experimental results of an investigation of a prototype tactile sensor design based on microbending losses in fiber optics. In particular, the parameters which determine the sensitivity of a fiber to bending losses were identified, experiments were performed on a multimode optical fiber, and a prototype tactile sensor was constructed and tested. Results indicate that the limiting factor on the performance of the tactile sensor was the visco-elastic behavior of the fiber's cladding.