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| Photo credit: pixabay.com |
Unmanned
Aerial Systems (UAS) are developing at a very quick pace; a rapid area of this
development is micro UAS. These small
vehicles can be deployed from a backpack and controlled by a laptop or an Ipad
in the battle field. The display design
in these vehicles must make efficient and safe operation of the vehicle
intuitive, allowing operators ease of use in achieving the mission. Cooke, Pringle and Pederson (2006) evaluate
one such touch screen display. The
problems they found in testing operators working with these displays can be
improved upon by looking at some basic models of human information processing
and ecological approaches to display design for UAS swarm operations.
The
touch screen display analyzed operates in two modes. In map mode, a terrain map with the mission
path, UAS location and operator location are displayed. An inset window displays imagery collected
from the mission sensor. In full screen
video mode, the sensor image dominates the screen, the map display disappears,
and command buttons around the outside of the screen provide operational
control. Their tests revealed crashes
due to a lack of awareness of altitude and a lack of salient feedback for
inputs, among other challenges (Cooke, et al., 2006).
The
problem of altitude awareness can be seen in the pictoral representation of
both displays, where the altitude is presented in small text at the top of the
screen, outside of the primary field of attention inside a black frame. In his paper on multiple resource theory,
Christopher Wickens proposes a multiple resource model to explain how operators
control attention (2008). In the case of
this display, nearly all of the information is visual, and focal, utilizing the
same modality of perception. Although
the map and sensor information is more spatial and the altitude display is more
verbal in nature, utilizing two different “codes of processing” as described by
Wickens, there is a bottle neck of processing in the visual level. In addition, the altitude readout is focal in
nature, so if the operator has focused his or her attention on the pictoral
representation of either the map mode or the full screen video mode, the
altitude information is not triggered by the unfocused awareness of peripheral
vision. One solution for the
presentation of altitude can be found in Fuchs, Brost, deCroon, van Passen and
Mulder’s (2014) proposal for an ecological display design for swarm UAV
operations. Their ecological design
provides an inset window which displays the airspeed and current waypoint of
each of four UAS. Because it is an inset
on the main display, the information is brought into the awareness of the
operator in a way that it is not in the touch screen display of Cooke et al.;
as an inset, the altitude information is closer to the operator’s primary field
of view. Another method to increase
operator attention on altitude is to add an auditory cue for altitude. By Wickens’ model of multiple resources,
employing and auditory cue would take advantage of a separate modality for
perception, and better equip the operator with limited perceptual space to
attend to the altitude stimulus (2008).
In takeoff and landing modes, the rate of auditory altitude information
could be increased to encourage the increase situational awareness required in
these stages of flight. Finally,
programming minimum safe altitudes for the flight profile and incorporating a
visual and or auditory alert would draw the operators awareness to the hazard.
Lack
of salient feedback for controller inputs has a direct parallel to manned
aircraft operation. Even aircraft do not
always respond immediately to an input, as a military jet pilot who transitions
to a heavy aircraft would likely report.
The difference is the manned aircraft operator has a control surface
that the pilot manipulates leaving little doubt, short of a failure of the
flight control system, that the input has been received by the machine. The touch interaction system studied by
Cooke et al. utilizes a low cognitive, perceptual, and motor load interaction
device with a low contribution to overall fatigue (Wickens, Lee, Liu &
Becker, 2004). However, a good design
must include feedback of the control state in order to indicate the system
response to the operator (Wickens et al., 2004). In the case of the touch screen, an ideal
feedback response would be a vibration such as one would experience with a
modern touchscreen smartphone. Once
again this feedback would utilize a separate perceptual modality and take full
advantage of the human sensory system, informing the operator the minute the
system has registered a control input.
The
touchscreen display studied by Cooke et al (2006) has shortcomings that they
discover even as they conduct their studies.
A more human-centered display design can reduce training time and
enhance operator capabilities in high workload tasks. Making the altitude and feedback cues more
salient and utilizing different modes of perception optimize the operator’s
ability to integrate all of the information critical to operating a UAS safely
and conduct the mission effectively.
References
Cooke,
N. J., Pringle, H., & Pedersen, H. (Eds.). (2006). Human Factors of
Remotely Operated Vehicles, Volume 7. Amsterdam, NLD: JAI Press. Retrieved from
http://www.ebrary.com
Fuchs, C.,
Borst, C., de Croon, G. C. H. E., van Paassen, M. M. (René), & Mulder, M.
(2014). An Ecological Approach to the Supervisory Control of UAV Swarms. International
Journal of Micro Air Vehicles, 6(4), 211–230.
doi:10.1260/1756-8293.6.4.211
Wickens, Christopher, et al. (2004). An
Introduction to Human Factors Engineering. Upper Saddle River, New Jersey:
Pearson Education.
Wickens, C.
D. (2008). Multiple resources and mental workload. Human Factors, 50(3),
449–55. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/18689052
