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1.5 Teleoperation
because of the limited field of view; essentially there is no peripheral vision.
Also, the camera may not be transmitting new images very fast because the
communication link has a limited bandwidth, so the view is jerky. Most peo-
COGNITIVE FATIGUE ple quickly experience cognitive fatigue; their attention wanders and they may
even experience headaches and other physical symptoms of stress. Even if
SIMULATOR SICKNESS the visual display is excellent, the teleoperator may get simulator sickness due
to the discordance between the visual system saying the operator is moving
and the inner ear saying the operator is stationary. 141
Another disadvantage of teleoperation is that it can be inefficient to use for
applications that have a large time delay. 128 A large time delay can result in
the teleoperator giving a remote a command, unaware that it will place the
remote in jeopardy. Or, an unanticipated event such as a rock fall might occur
and destroy the robot before the teleoperator can see the event and command
TELEOPERATION the robot to flee. A rule of thumb, or heuristic, is that the time it takes to do
HEURISTIC a task with traditional teleoperation grows linearly with the transmission
delay. A teleoperation task which took 1 minute for a teleoperator to guide a
remote to do on the Earth might take 2.5 minutes to do on the Moon, and 140
minutes on Mars. 142 Fortunately, researchers have made some progress with
PREDICTIVE DISPLAYS predictive displays, which immediately display what the simulation result of
the command would be.
The impact of time delays is not limited to planetary rovers. A recent ex-
ample of an application of teleoperation are unmanned aerial vehicles (UAV)
used by the United States to verify treaties by flying overhead and taking
videos of the ground below. Advanced prototypes of these vehicles can fly
autonomously, but take-offs and landings are difficult for on-board computer
control. In this case of the Darkstar UAV (shown in Fig. 1.8), human oper-
ators were available to assume teleoperation control of the vehicle should
it encounter problems during take-off. Unfortunately, the contingency plan
did not factor in the 7 second delay introduced by using a satellite as the
communications link. Darkstar no. 1 did indeed experience problems on
take-off, but the teleoperator could not get commands to it fast enough be-
fore it crashed. As a result, it earned the unofficial nickname “Darkspot.”
Another practical drawback to teleoperation is that there is at least one
person per robot, possibly more. The Predator unmanned aerial vehicle has
been used by the United States for verification of the Dayton Accords in
Bosnia. One Predator requires at least one teleoperator to fly the vehicle and
another teleoperator to command the sensor payload to look at particular
areas. Other UAVs have teams composed of up to four teleoperators plus a
fifth team member who specializes in takeoffs and landings. These teleop-