Tactile objects based on an amplitude disturbed diffraction pattern method

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible.This is an author-deposited version published in: http://sam.ensam.eu Handle ID: .http://hdl.handle.net/10985/6519 To cite this version :Yuan LIU, Jean-Pierre NIKOLOVSKI, Nazih MECHBAL, Moustapha HAFEZ, Michel VERGÉ -Tactile objects based on an amplitude disturbed diffraction pattern method -2009Any correspondence concerning this service should be sent to the repository Administrator : archiveouverte@ensam.eu Tactile sensing is becoming widely used in human-computer interfaces. Recent advances in acoustic approaches demonstrated the possibilities to transform ordinary solid objects into interactive interfaces. This letter proposes a static finger contact localization process using an amplitude disturbed diffraction pattern method. The localization method is based on the following physical phenomenon: a finger contact modifies the energy distribution of acoustic wave in a solid; these variations depend on the wave frequency and the contact position. The presented method first consists of exciting the object with an acoustic signal with plural frequency components. In a second step, a measured acoustic signal is compared with prerecorded values to deduce the contact position. This position is then used for human-machine interaction ͑e.g., finger tracking on computer screen͒. 3,4 or time-of-flight techniques, 5,6 the timereversal technique can be applied to most solids without any prior knowledge of acoustic properties. However, many human-machine interfaces prefer "touch" sensing than impact localization, because touch is perceived as a more userfriendly interaction. 7,8 Indeed, some modern interaction modes such as "multitouch" 9 are difficult to achieve with "impacts," since it requires generating several impacts simultaneously on the tactile surface. Tactile objects based on an amplitude disturbed diffraction pattern methodRecently, an alternative method based on the crosscorrelation of selective absorption of the vibration modes has been presented. 10 This process is suitable for static contact localization. However, this process based on an absorption technique cannot address some particular uses such as stylus tip localization. In that case, contact creates more diffraction effect of the propagating acoustic waves than absorption. In this letter, we propose a tactile process based on an amplitude disturbed diffraction pattern ͑ADDP͒ phenomenon of an impulse acoustic wave. It expresses the following physical phenomenon: a human finger ͑or stylus͒ in contact with the objects affects the acoustic wave propagation in the solid. These disturbances depend on the finger position and the frequency of excited signal. With analysis and a calibration procedure of this variation, we can locate precisely the contact position.In the following examples, two emitters ͑piezoelectric transducers Pz27 type by Ferroperm, Denmark͒ transmit repetitive Lamb waves ͑period 1 ms͒ in t...

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“…Jean-Pierre Nikolovski continues to explore innovative technology for acoustic interfaces and touch devices as a research engineer at the French Atomic Energy Commission (CEA) [24].…”

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“…These involve interaction of a tactile object such as a human finger with a solid surface in either passive [1]- [3] or active [4]- [6] forms. Plates are strongly confined along the thickness.…”