Preliminary design of a multi-touch ultrasonic tactile stimulator

Abstract

International audience— This paper presents a method to control ultrasonic waves on a beam, allowing to obtain a Multi-touch ultrasonic tactile stimulation in two points, to give the sensation to two fingers, from two piezoelectric transducers. The multi-modal approach and the vector control method are used to regulate the vibration amplitude, in order to modulate the friction coefficient with the fingers. An analytical modelling is presented, with experimental validation. Finally a psychophysical experiment shows that a multi-touch ultrasonic tactile stimulation is possible

Control and evaluation of a 2-D multimodal controlled-friction display

“…In [9] we have shown that the friction at P 1 (resp. P 2 ) is a function of W 1 (resp.W 2 ) at the condition that the wavelength of the two mode shapes is high enough to produce very different friction reduction felt by a user moving one finger at the nodes and antinodes of vibration.…”

“…The authors presented 4 different tactile maps, but they also point out that the method has the disadvantage to produce audible christophe.giraud-audine@ensam.eu noise by principle. In [9], [10], we presented a multimodal approach which allows a programmable tactile stimulation on two fingers located on two independent positions, on a 1D device. It consists in using two vibration modes which are energized at the same frequency, and which are superimposed in order to control the vibration amplitude at the positions of two fingers.…”

Modal Superimposition for Multi-fingers Variable Friction Tactile Device

“…If a stationary wave would have been set on the beam, then the users would have felt nodes and antinodes of vibration successively on each fingers, and would not have detected a finger smoother than the other [4]. Moreover, 5 subjects found the beam more slippery for the left finger compared to the beam without any vibration.…”

“…Indeed, they do not allow to precisely control the vibration amplitudes at two or more different positions simultaneously. To cope with this issue, [4] proposed to superimpose two vibration modes, and to control the vibration amplitude of each mode according to the position of two fingertips. This principle take advantages of modal superimposition by using two modes which half wavelength is higher than 12 mm.…”

Sparse Actuator Array Combined with Inverse Filter for Multitouch Vibrotactile Stimulation

“…Phased actuator array can focus ultrasounds to create localized mid-air sensations [9]. Modal synthesis combines vibration modes of the surface to vibrate chosen locations while cancelling others [10], [11]. All those techniques operate remotely from actuators, in their far field where diffraction limits the resolution to the wavelength scale.…”