WIP wearable haptics

1-introduction/related-work/1-wearable-haptics.tex

@@ -1,7 +1,7 @@
-\section{Wearable Haptics for the Hand}
+\section{Rendering Objects with Wearable Haptics}
 \label{wearable_haptics_hand}
 
-To understand how wearable haptics have been used to render haptic properties of virtual and augmented objects objects, we first need to describe how the hand senses and acts on its environment to perceive the haptic properties of real everyday objects.
+To understand how wearable haptics have been used to render haptic properties of virtual and augmented objects, we first need to describe how the hand senses and acts on its environment to perceive the haptic properties of real everyday objects.
 
 
 \subsection{The Haptic Sense}
@@ -367,29 +367,46 @@ Un toucher statique peut suffire pour certaines propriétés, mais une action mo
 Enfin, il est fréquent qu'un indice perceptuel soit particulièrement important dans la perception d'une propriété, mais une certaine constance perceptuelle semble possible en compensant son absence par d'autres, par exemple en touchant indirectement via un outil tenu en main.
 
 
-\subsection{Wearable Haptics}
+\subsection{Wearable Haptics for the Hand}
 \label{wearable_haptics}
 
+Nous présentons ici seulement un survol des dispositifs haptiques portables pour la main et des rendus qu'ils permettent de générer.
+En particulier, nous nous intéressons aux actuateurs portables qui n'empêchent pas de toucher et interagir avec l'environnement réel et aux rendus de propriétés haptiques d'objets virtuels ou augmentés.
+Pour une revue complète, voir \textcite{pacchierotti2017wearable}.
 
 \subsubsection{Wearable Haptic Devices}
 \label{wearable_haptic_devices}
 
+\paragraph{Level of Wearability}
+
 % Tradeoff realistic and cost + analogy with sound, Hi-Fi costs a lot and is realistic, but 40$ BT headphone is more practical and enough, as cutaneous feedback without kinesthesic could be enough for wearable haptics and far more affordable and comfortable than world- or body-grounded haptics + cutaneous even better than kine for rendering surface curvature and fine manipulation
 
 % Level of wearability is inverse of kinesthetic feedback capability
 
-\paragraph{Level of Wearability}
+\paragraph{Moving Platforms}
 
-\paragraph{Moving Actuators}
+\paragraph{Shearing and Compression Belts}
 
 \paragraph{Vibrotactile Actuators}
 
-\paragraph{Kinesthetic Actuators}
+Vibrotactile actuators are the most common and simplest wearable haptic interfaces, and are available as consumer products.
+\textcite{choi2013vibrotactile} provide a detailed review.
+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:
+\begin{itemize}
+    \item An \ERM is a \DC motor that rotates an off-center mass when a voltage or current is applied. \ERMs are easy to control, inexpensive and can be encapsulated in a few millimeters cylinder or coin form factor. They are widely used in many applications and consumer devices. 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.
+    \item A \LRA consists of a coil that creates a magnetic field from an \AC to oscillate a magnet attached to a spring, as an audio loudspeaker. They are more complex to control than \ERMs. Each \LRA is designed to vibrate with maximum amplitude at a given frequency, but won't vibrate efficiently at other frequencies.
+    \item A \VCA is a \LRA but capable of generating vibration at two \DoF, with an independent control of the frequency and amplitude of the vibration. However, they are larger in size than \ERMs and \LRAs.
+    \item Piezoelectric actuators deform a solid material when a voltage is applied. They are very small and thin, and allow two \DoFs of amplitude and frequency control. However, they require high voltages to operate and are difficult to control.
+\end{itemize}
 
-
-\subsubsection{Renderings of Haptic Materials}
+\subsubsection{Tactile Renderings of Object Properties}
 \label{wearable_haptic_renderings}
 
+Le rendu tactile des propriétés haptiques consiste à modéliser et reproduire des sensations cutanées virtuelles comparables à celles perçues lors de l'interaction avec des objets réels.
+
+\paragraph{Contact}
+
 \paragraph{Texture}
 
 \paragraph{Hardness}