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Erwan Normand
2024-09-30 11:47:29 +02:00
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1-background/related-work/2-wearable-haptics.tex
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@@ -12,7 +12,7 @@ The haptic system should be hand-held or worn, \eg on the hand, and \enquote{not
\label{wearability_level}
Different types of haptic devices can be worn on the hand, but only some of them can be considered wearable.
\textcite{pacchierotti2017wearable} classify them into three levels of wearability, as illustrated in the \figref{pacchierotti2017wearable}.
\textcite{pacchierotti2017wearable} classify them into three levels of wearability, as illustrated in \figref{pacchierotti2017wearable}.
An increasing wearability resulting in the loss of the system's kinesthetic feedback capability.
\begin{subfigs}{pacchierotti2017wearable}{
@@ -75,9 +75,9 @@ However, these platforms are specifically designed to provide haptic feedback to
A pin-array is a surface made up of small, rigid pins arranged close together in a grid and that can be moved individually.
When placed in contact with the fingertip, it can create sensations of edge, pressure and texture.
The \figref{sarakoglou2012high} shows an example of a pin-array consisting of \numproduct{4 x 4} pins of \qty{1.5}{\mm} diameter and \qty{2}{\mm} height, spaced at \qty{2}{\mm} \cite{sarakoglou2012high}.
\figref{sarakoglou2012high} shows an example of a pin-array consisting of \numproduct{4 x 4} pins of \qty{1.5}{\mm} diameter and \qty{2}{\mm} height, spaced at \qty{2}{\mm} \cite{sarakoglou2012high}.
Pneumatic systems use a fluid such as air or water to inflate membranes under the skin, creating sensations of contact and pressure \cite{raza2024pneumatically}.
Multiple membranes are often used in a grid to simulate edges and textures, as in the \figref{ujitoko2020development} \cite{ujitoko2020development}.
Multiple membranes are often used in a grid to simulate edges and textures, as in \figref{ujitoko2020development} \cite{ujitoko2020development}.
Although these two types of effector can be considered wearable, their actuation requires a high level of mechanical and electronic complexity that makes the system as a whole not portable.
\begin{subfigs}{normal_actuators}{
@@ -133,7 +133,7 @@ They are small, lightweight and can be placed directly on any part of the hand.
All vibrotactile actuators are based on the same principle: generating an oscillating motion from an electric current with a frequency and amplitude high enough to be perceived by cutaneous mechanoreceptors.
Several types of vibrotactile actuators are used in haptics, with different trade-offs between size, proposed \DoFs and application constraints.
An \ERM is a direct current (DC) motor that rotates an off-center mass when a voltage or current is applied (\figref{precisionmicrodrives_erm}). \ERMs are easy to control, inexpensive and can be encapsulated in a few millimeters cylinder or coin form factor. However, they have only one \DoF because both the frequency and amplitude of the vibration are coupled to the speed of the rotation, \eg low (high) frequencies output at low (high) amplitudes, as shown on \figref{precisionmicrodrives_erm_performances}.
An \ERM is a direct current (DC) motor that rotates an off-center mass when a voltage or current is applied (\figref{precisionmicrodrives_erm}). \ERMs are easy to control, inexpensive and can be encapsulated in a few millimeters cylinder or coin form factor. However, they have only one \DoF because both the frequency and amplitude of the vibration are coupled to the speed of the rotation, \eg low (high) frequencies output at low (high) amplitudes, as shown in \figref{precisionmicrodrives_erm_performances}.
\begin{subfigs}{erm}{Diagram and performance of an \ERM. }[][
\item Diagram of a cylindrical encapsulated \ERM. From Precision Microdrives~\footnotemark.
@@ -148,7 +148,7 @@ An \ERM is a direct current (DC) motor that rotates an off-center mass when a vo
A \LRA consists of a coil that creates a magnetic field from an alternative current (AC) to oscillate a magnet attached to a spring, as an audio loudspeaker (\figref{precisionmicrodrives_lra}).
They are more complex to control and a bit larger than \ERMs.
Each \LRA is designed to vibrate with maximum amplitude at a given resonant frequency, but won't vibrate efficiently at other frequencies, \ie their bandwidth is narrow, as shown on \figref{azadi2014vibrotactile}.
Each \LRA is designed to vibrate with maximum amplitude at a given resonant frequency, but won't vibrate efficiently at other frequencies, \ie their bandwidth is narrow, as shown in \figref{azadi2014vibrotactile}.
A voice-coil actuator is a \LRA but capable of generating vibration at two \DoF, with an independent control of the frequency and amplitude of the vibration on a wide bandwidth.
They are larger in size than \ERMs and \LRAs, but can generate more complex renderings.