Tactile sensors are needed for many emerging robotic and telepresence applications such as keyhole surgery and robot operation in unstructured environments. We have proposed and demonstrated a tactile sensor consisting of a fibre Bragg grating embedded in a polymer "finger". When the sensor is placed in contact with a surface and translated tangentially across it measurements on the changes in the reflectivity spectrum of the grating provide a measurement of the spatial distribution of forces perpendicular to the surface and thus, through the elasticity of the polymer material, to the surface roughness. Using a sensor fabricated from a Poly Siloxane polymer (Methyl Vinyl Silicone rubber) spherical cap 50 mm in diameter, 6 mm deep with an embedded 10 mm long Bragg grating we have characterised the first and second moment of the grating spectral response when scanned across triangular and semicircular periodic structures both with a modulation depth of 1 mm and a period of 2 mm. The results clearly distinguish the periodicity of the surface structure and the differences between the two different surface profiles. For the triangular structure a central wavelength modulation of 4 pm is observed and includes a fourth harmonic component, the spectral width is modulated by 25 pm. Although crude in comparison to human senses these results clearly shown the potential of such a sensor for tactile imaging and we expect that with further development in optimising both the grating and polymer "finger" properties a much increased sensitivity and spatial resolution is achievable.
|Title of host publication||Optical sensing technology and applications|
|Editors||Francesco Baldini, Jiri Homola, Robert A. Lieberman, Miroslav Miler|
|Place of Publication||Czech Republic|
|Number of pages||8|
|ISBN (Print)||978-0-8194-6713-3, 0-8194-6713-8|
|Publication status||Published - May 2007|
|Event||Optical Sensing Technology and Applications - Prague, United Kingdom|
Duration: 16 Apr 2007 → 18 Apr 2007
|Conference||Optical Sensing Technology and Applications|
|Period||16/04/07 → 18/04/07|
Bibliographical noteBarbara Cowie ; Thomas Allsop ; John Williams ; David Webb ; Ian Bennion and Matthew Fisher "An optical fiber Bragg grating tactile sensor", Proc. SPIE 6585, Optical Sensing Technology and Applications, 65850I (May 16, 2007);
Copyright 2007 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
- Fibre Bragg Grating sensor
- tactile sensor
- optical fibre sensor