Biomedical Engineering Reference
In-Depth Information
F out
F out
(a)
+
V in
+
V in
Piezoelectric
actuator element
(b)
Figure 7.11
(a) Bending of a bimorph and (b) bending elements arranged into an array [36 - 38]
fact that all the actuators bend around the same axis, this was not found to be a limitation
since, at such a small scale, the resulting sensations seem to be indifferent to the details
of skin stretch/shear orientation.
In another research work, Kwon et al . described the development of a piezoelectric-
based planar distributed tactile display capable of displaying textures [35, 39]. The tactile
display is composed of a 6 × 5 pin array actuated by 30 piezoelectric bimorphs.
7.3.6 Air Jet Tactile Displays (Surface Indentation)
A new tactile stimulation method is proposed in [40 - 42] by controlling the suction
pressure. This method is based on our discovery of a tactile illusion where we feel as if
something like a stick is pushing up into the skin surface when we pull skin through a
hole by lowering the air pressure.
This illustration shows how our tactile mechanoreceptors detect strain energy, but
cannot differentiate between positive or negative stress. Therefore we are unable to dis-
criminate suction from compression (see Figure 7.12a,b).
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