Audi MMI touch
controller. Figure
3 (right). Adaptive
control elements
can dynamically
change their shape
to communicate
information to the
driver in an eyes-free manner [ 9].
projects that are looking into possibilities to add haptic feedback to
touch interaction.
Touch Interaction and
Haptic Feedback
Depending on the position of the
screen (e.g., in the middle of the
dashboard), it can be cumbersome
for the driver to reach and touch
the central information display.
Decoupled input devices like the
multifunctional controllers mentioned before allow us to overcome
this issue. Similarly, touch input
decoupled from the display is used
in the MMI touch interface [ 6] developed by Audi: A touchpad on the
center stack close to the gearshift
allows drivers to perform gestures,
input characters, or execute shortcut commands (assigned to certain
areas of the input device) to control
the infotainment system (see Figure
2). Since this is a traditional touchpad, this device offers neither visual
nor haptic feedback, which makes it
difficult to implement, for example,
virtual buttons.
To add vibrotactile feedback,
Richter et al. created the Hap Touch
system, which enriched a touch-
screen with force sensors and a
linear actuator able to move the
entire display in z-direction [ 7].
When the screen is touched, the
system can sense a finger position
and provide tactile information. If
the display is pressed harder, fur-
ther interaction, such as pressing
a button, can be implemented.
March + April 2013