Phase V Initial Updated Design Proposal with
Enabling Technologies:
Cockpit Redesign
for Accommodation of Disabled Pilots
Chris C. Beeney
February 20, 2019
Embry Riddle
Aeronautical University
UNSY 431: Unmanned
Systems Human Factors Considerations
Evaluation of the Existing/Current System Design
In this section, the current design of a typical
cockpit will be evaluated in regards to the yoke, the rudder pedals, and the
brakes specifically. The reason for the current design of each system,
their shortcomings, and the human factors that affect them will be considered.
The yoke is also known as the control stick.
In some designs this is a literal stick (with or without handles) and in
others it looks like half a steering wheel for a car. The yoke was built
to manually control the plane using pulleys and later hydraulics with
actuators. The technology of the time
was before the invention of computers, so everything was manual. At the
time, human factors were not the focus of design, so the mechanical
implementation of the yoke expected the pilot to conform to the system. This becomes a problem for pilots that are
amputees. In the past, people missing an arm could not fly reasonably but
newer technologies in prosthetics allow those with missing limbs to interact
with the yoke. In order to do so, the
prosthetic needs to be attached to the yoke and becomes a flight risk if the
unit detaches from the pilot (Hawkins, 2014).
The need for nose correction in the air prompted
the invention of a rudder. Typically the rudder consists of two pedals
that are attached to each other. The
pilot must press down on one or the other with their foot to control the
rudder. Rudders were also invented before the digital age and are
manually operated; some of the newer ones use hydraulics with actuators like
the yoke. Also like the yoke, rudders
were designed with the thought that pilots must conform to the system. To
that end, some amputees must attach the rudder to their amputated leg with a
band and do a dance to operate it (Hawkins, 2014). The act of using a rudder is also tedious
work because it is essentially a series of minute corrections in direction.
One aspect of human factors considerations is to avoid putting the user
in monotonous jobs (Salvendy, 2012).
Fitt’s principles point out that machines are very good at performing
repetitive tasks and could help alleviate this shortcoming (de Winter, &
Dodou, 2014).
The braking system has existed since airplanes had wheels.
Braking has always been a manual ordeal because it involves kinetic
friction. The shortcoming in this system pertains only to those with
amputated legs. Double amputees have a
hand control to operate the brake (Hawkins, 2014). This is another example
of the system being designed a certain way and expecting the user to adapt to
it; an additional unit had to be added for the double leg amputee to adapt.
Proposed Task Assignment Using Fitt’s Principles
In this section, Fitt’s principles will be used to
determine which of the three subtasks above should be re-assigned to be
performed by a machine. Paul Fitts created a list of 11 statements
describing which actions are performed better by a machine or by a human (de
Winter, & Dodou, 2014). A brief summary
of the subtasks addressed in this paper can be seen in Table 2 but will be
discussed in detail in the following paragraphs.
The yoke is required in order to steer the plane.
Directionality is very important when flying a plane and requires an
understanding of the surrounding environment. But a steady course could
be automated. Because of this, a human
should be in control of the yoke but may be assisted by a machine using
autopilot. A semi-automated yoke would offer the pilot stabilized
control; the plane will return to wings level mode after the yoke is used to
steer in the desired direction (Barnhart,
Marshall, Most, & Shappee, 2016). Fitt’s second statement
applies when arguing for human control because pattern recognition is crucial
for navigating; especially when recognizing a runway at night. Fitt’s
third statement applies when arguing for human control because improvisation is
sometimes needed such as unexpected collision avoidance. Fitt’s fifth and sixth statements apply
(often together) when arguing for human control because deductive reasoning and
the ability to make judgements are important aspects of steering the plane
during times such as course correcting for inclement weather on the horizon (de
Winter, et. al., 2014). Fitt’s first statement applies when arguing for
machine control because the autopilot can smoothly apply the needed force to
re-align the plane with the horizon precisely.
The rudder is required to assist in directing the
plane appropriately. The plane would be more difficult to align to the
planned trajectory without the rudder. Because the rudder consists of
reactive minute actions, it could be automated entirely. As with the yoke, stabilized control would
afford the plane with the appropriate level of rudder adjustments without human
intervention. Fitt’s second statement arguing for machine control applies
because rudder control is a repetitive routine task. Fitt’s fourth statement arguing for machine
control applies because the machine can perform complex calculation to
compensate for cross winds if it determines that the plane is off planned
course. Fitt’s fifth statement applies when arguing for machine control
because machines can handle many tasks at once easily so calculating wind speed
and adjusting the rudder while checking planned trajectory against GPS will not
be an issue.
The brake is important for keeping the aircraft
from rolling before and after flight. Usually the plane will need to taxi
to the runway and then wait for ground control to authorize the flight once it
is safe. Without brakes, the plane would begin to accelerate as soon as
the engine is turned on and take off regardless of whether the pilot has
navigated to the runway or not. Upon landing, the brakes are essential
for stopping the plane safely. Without
artificial intelligence to determine when to apply brakes, these are best left
to the human. Fitt’s third statement applies when arguing for human
control because takeoff procedures are usually flexible; the pilot must wait
until ground control clears the takeoff.
Fitt’s fourth statement applies when arguing for human control because
the pilot must recognize the appropriate time to apply the brakes.
Table 2
Summary of the Proposed System
Task Assignments
|
Task
|
Human Assignment
|
Machine
Assignment
|
|
Brake
|
x
|
|
|
Rudder
|
x
|
|
|
Steer
|
x
|
x
|
Initial System Component Design
A new digital console should be created to house controls
for the steering and braking subtasks as well as override rudder control.
The console should be attached to the side of the cockpit on an
adjustable arm so that users of differing arm lengths can adjust for reach
comfort of differing body types (Salvendy, 2012). The main console should
be a touch screen along with minimal important buttons. See figure 1 for overall
position.
Figure 1
The yoke actions can be represented with a D-Pad
configuration on the touch screen console in a digital format. With the
arrows or bars spaced far enough to avoid accidentally selecting the wrong direction
but close enough to be operated by one hand. The icons that represent the
directionality of the plane can easily be connected to actuators that control
the external mechanics of the plane much like the newer hydraulic systems in
place already. See Figure 2 for a closer look at the console’s digital
screen.
Figure 2
The rudder actions should be automated by the
autopilot but a separate toggle should be placed on the console bezel in case
an override is required. This way the pilot has the option of toggling
the rudder left, right, or neutral as needed but does not need to constantly
make adjustments under normal circumstances. See Figure 3 for console bezel
design.
Figure 3
The brakes should be a manual lever that provides haptic
feedback which is important in the braking process. The lever can be attached
to the bottom of the console, perhaps a long bar that extends the length of the
console. This can be seen in Figure 3.
Description of Enabling Technologies
The Alio Ground Control Station (GCS) is a fully touch
capable unit. This GCS could be modified
to fit in the cockpit. A new bezel would
need to be created that includes the manual toggle and brake lever. The professional unit costs $8,000 from
Chloeta.
Table 2
Summary of the Proposed
Enabling Technologies
|
Enabling Tech Description
|
Vendor(s)
|
Estimated Cost
|
Description of Application
in System Design
|
|
GCS touchscreen
|
Chloeta
|
$8,000
|
Touchscreen for aircraft
control
|
Reference List
Barnhart, R. K.,
Marshall, D. M., Most M.T., & Shappee, E. (2016). Introduction to
unmanned
aircraft systems. (2nd ed.). Boca Raton, FL: CRC Press, Taylor & Francis Group.
aircraft systems. (2nd ed.). Boca Raton, FL: CRC Press, Taylor & Francis Group.
Chloeta. (n.d.).
UAS Alio Ground Control Station. Retrieved from https://www.chloeta.com/wp-content/uploads/Spec-Sheet-UAS-Alio-Ground-Control-Station.pdf
de
Winter, J. C. F., & Dodou, D. (2014). Why the fitts list has persisted
throughout the history of function allocation. Cognition, Technology &
Work, 16(1), 1-11. doi:http://dx.doi.org.ezproxy.libproxy.db.erau.edu/10.1007/s10111-011-0188-1
Hawkins, K. (Aug. 14, 2014). How do amputees fly
planes? BBC News. Retrieved from https://www.bbc.com/news/magazine-28785171
Salvendy, G. (Ed.). (2012). Handbook of human
factors and ergonomics. Retrieved from https://ebookcentral.proquest.com
