Fig. 1. Structural diagram of distributed tactile sensor

Fig. 2. Principle of sensor. (a) Schematic diagram of total internal reflection principle; (b) schematic diagram of light paths in sensor under undeformed and compressed states

Fig. 3. Light field distribution characteristics and output power attenuation curve of lower core under pressure

Fig. 4. Simulation results of output light intensity from lower core. (a) Effect of inducing block width on output light intensity; (b) effect of inducing block refractive index on output light intensity

Fig. 5. Fabrication flowchart of dual-core flexible optical waveguide

Fig. 6. Cross-sectional view of tactile sensor with dual-core optical waveguide

Fig. 7. Picture of tactile sensor with dual-core optical waveguide

Fig. 8. Schematic diagram of experimental system

Fig. 9. Variations of core output spectra with normal pressure. (a) Upper core; (b) lower core

Fig. 10. Variations of core transmittance with force application position at 750 nm wavelength. (a) Upper core; (b) lower core

Fig. 11. Dynamic response curves of sensor at 750 nm wavelength. (a) Upper core; (b) lower core

Fig. 12. Photograph of sensor fatigue testing experimental system

Fig. 13. Fatigue test results of sensor. (a) Upper core; (b) lower core

Fig. 14. Cross-sectional and surface images of sensor before and after fatigue testing. (a) Cross-sectional view before testing; (b) 100×SEM image of surface before testing; (c) 500× SEM image of surface before testing; (d) cross-sectional view after testing; (e) 100× SEM image of surface after testing; (f) 500× SEM image of surface after testing