Biomedical Engineering Reference
In-Depth Information
Fig. 12.6
Global loop for multimodal rendering approaches of walking over virtual grounds. The
user (
left
) is interacting with the virtual world (
right
) through specific hardware devices. Rendering
techniques allows multimodal feedback by taking into account the user's input and the virtual
environment. The feedback are provided through visual, acoustic and haptic interfaces
can be exploited to allow one modality (for example, vision) to render sensations
that would normally be presented via another modality that may not be feasible to
reproduce (e.g., via haptic force feedback). Some of these approaches are described
at the end of the Sect.
12.3.5
.
12.3.4 Display Configurations
In this paragraph, we discuss two types of devices capable of the generation of
multimodal cues for the interaction with virtual grounds, and corresponding to two
different approaches: actuated floors, an array of sensors an actuators laid out on a
given space transmitting the different cues to the user stepping on them; and actuated
shoes, mobile devices worn by the user with sensors and actuators embedded in
the shoes.
The two approaches stimulate the foot with the simulated high-frequency mechan-
ical feedback, viz. 30-800 Hz, from foot-ground interactions. As it turns out, a wide
variety of sensations can be produced this way, including those that would nor-
mally be ascribed to kinesthesia [
109
]. Auditory feedback is also generated by the
resulting prototypes, as a by-product of the vibrotactile actuators aboard them, or
via associated loudspeaker arrays, and visual feedback may be supplied via top-
down video projection systems. One approach is to tile a floor and actuate each
tile according to the movement and interaction of the walker or the user. Another
approach is to provide the walker with shoes augmented with appropriate transducers.
In addition to the devices described in other sections of this chapter, the vibrotactile
augmentation of touch surfaces has been widely investigated for HCI applications
