This thesis deals with the tribological and dynamic aspects of tactile perception given by the scanning of the finger on a surface. The attention is focused on a direct analysis of the vibration spectrum characteristics, induced by the surface features that is a relatively new research field. In fact, it is accepted that vibrations activate the tactile afferents and their essential role for the perception of fine textures (duplex theory of tactile texture perception) but it is still unknown the link with the surface texture characteristics and the features of the induced vibration spectra. The work is aimed to contribute to a better understanding of the mechanisms of the tactile sense, that is basilar for manifold different applications: textile quality quantification, ergonomics of everyday objects (which largely affects their commercial competitiveness), identification of surface imperfections, the design of tactile communication devices, the development of artificial tactile sensors for intelligent prostheses or robotic assistants, the development of human-machine interfaces for interaction with virtual realities or teleoperation systems, such as for telediagnosis or microsurgery, reproducing real perception (virtual reality), increasing the human perception (augmented reality), development of tests for evaluation of tactile sensitivity during diagnosis or monitoring process in rehabilitation. The study of a finger that moves on a surface involves different difficulties that are related to the material characteristics and to the measurements themselves. For these reasons, a new experimental set-up, named TriboTouch, has been developed to reproduce the finger/surface scanning phenomena under real values of the contact feature (scanning velocity and amplitude, surface roughness, etc..), avoiding undesired vibrations. The test bench has been designed to guarantee the measurements reproducibility and to perform measurements without introducing external noise. The set-up permits to carry out both measurements of the global dynamics and local ones (at the contact zone) employing a silicone fake finger. In the presented analysis, the behavior of the right hand index finger scanning on the surface sample with periodical and isotropic roughness and on textiles has been investigated for different scanning speed, highlighting the role of fingerprints A simple numerical model have been developed for reproducing the behavior of the induced vibrations when sliding two periodical surfaces and the numerical results have been compared with the experimental ones. The presented work has shown the possibility to obtain objective indexes for the tactile perception characterization, by means of the friction induced vibration spectrum analysis, in agreement with the neurophysiological studies present in literature.
| Identifer | oai:union.ndltd.org:CCSD/oai:tel.archives-ouvertes.fr:tel-00715822 |
| Date | 16 December 2011 |
| Creators | Fagiani, Ramona |
| Publisher | INSA de Lyon |
| Source Sets | CCSD theses-EN-ligne, France |
| Language | English |
| Detected Language | English |
| Type | PhD thesis |
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