From 27e87730a62b3f831bf1e77420aa45caf4454dc6 Mon Sep 17 00:00:00 2001 From: Thomas Pietrzak Date: Mon, 13 Sep 2021 10:02:27 +0200 Subject: [PATCH] Fini printgets --- tex/2-output.tex | 46 ++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 40 insertions(+), 6 deletions(-) diff --git a/tex/2-output.tex b/tex/2-output.tex index fc8749a..f857e12 100644 --- a/tex/2-output.tex +++ b/tex/2-output.tex @@ -1890,12 +1890,46 @@ We describe the design of the vibrotactile feedback for tactile buttons in~\cite \subsubsection{Discussion and conclusion} -put together existing building blocks to design a whole system - -interdisciplinary skills and knowledge - -low vibration amplitude => clamping arrea => localized haptic feedback - +This work required interdisciplinary skills and knowledge to put together existing building blocks to design a whole system. +This is what I consider a strength of Human-Cumputer Interaction research, at least the way I do it. +We have skills in many research domains, which allows us to design, implement and evaluate interactive systems. +When more expertise is required, we can efficiently collaborate with experts in other domains. +In this project we collaborated with experts in material science who designed the tactile actuators modeled and simulated their vibrations in a theoretical environment. + +%Our colleagues who designed the tactile actuators modeled and simulated their vibrations in a theoretical environment. +In these simulations, there was no finger, and the clamping of the surface was perfect, without tension. +In practice, the finger dampens the vibration and it is unsure other vibrations disrupt the perceptions of the vibrations produced by the device. +In particular the main scenario of the project\footnote{\href{https://cordis.europa.eu/project/id/645145}{H2020 Happiness}, grant agreement \#645145} was a car dashboard. +Cars produce vibrations of various frequencies and amplitudes because of the engine and the road. +Other partners of the project actually evaluated the perception of this tactile feedback in a real-case scenario~\cite{ng17}. +On our side, we noticed the clamping of research prototypes is not trivial. +It is difficult to glue the flexible substrate on a rigid surface with a clamping area so that the substrate remains perfectly flat on the clamping area. +It creates a bi-stable condition on a surfaces that produces an undesirable click sensation when touching it with a finger. +Therefore we must apply tension to hold the flexible substrate flat on the rigid surface. +It is well known that adjusting the tension of a drum head on a drum shell changes its resonnant frequency. +This is precisely the way we tune a drum. +The same principle applies to our setup. +However the vibration was still perceptible, with no bi-stable condition. + +A difficulty of this work was the long manufactoring process of actuators. +It required weeks of planning, and the actuators were printed in a white clean room. +This long process limited the number of iterations we could perform for designing the actuator layout and properties such as thickness, shapes and sizes. +Therefore at each iteration we printed several configurations, then tested them to select the most appropriate one. +However it limited the type of user studies we could perform. + +One of the major differences between this vibrotactile technology and other piezo-based actuators is that their thickness is very low. +It is an advantage because it uses less materials. +It is also a drawback because the amplitude of vibration is much lower. +Therefore the vibration hardly transmits to thick surfaces like a 1mm thick plastic dashboard. +The alternative is placing the actuators on holes that define a clamping area so that the substrate resonnates like a drum shell. +This solution brings an interesting property that other technologies do not have. +The vibration is localized to the clamping area, therefore it is localized. +Hence with a dashboard with several buttons and sliders, it is possible to vibrate buttons individually. + + +%slow iterations because long manufactoring process of actuators + +%low vibration amplitude => clamping arrea => localized haptic feedback \subsection{Actuated computer peripherals} -- 2.30.2