Teleoperation

Teleoperation

Teleoperation is when a human operator TELEOPERATION controls a robot from a distance (tele
means “remote”). The connotation of teleoperation is that the distance is too
great for the operator to see what the robot is doing, so radio controlled toy
cars are not considered teleoperation systems. The operator and robot have
some type of master-slave relationship. In most cases, the human operator
sits at a workstation and directs a robot through some sort of interface, as
seen in Fig. 1.6.
The control interface could be a joystick, virtual reality gear, or any number
of innovative interfaces. The human operator, or teleoperator, is often
LOCAL referred to as the local (due to being at the local workstation) and the robot
REMOTE as the remote (since it is operating at a remote location fromthe teleoperator).
The local must have some type of display and control mechanisms, while the
remote must have sensors, effectors, power, and in the case of mobile robots,
mobility.141 The teleoperator cannot look at what the remote is doing directly,
either because the robot is physically remote (e.g., on Mars) or the local has
to be shielded (e.g., in a nuclear or pharmaceutical processing plant hot cell).
SENSORS Therefore, the sensors which acquire information about the remote location,
DISPLAY the display technology for allowing the operator to see the sensor data, and
COMMUNICATION LINK the communication link between the local and remote are critical components
of a telesystem.141
Teleoperation is a popular solution for controlling remotes becauseAI technology
is nowhere near human levels of competence, especially in terms of

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 people
quickly experience cognitive fatigue; COGNITIVE FATIGUE their attentionwanders and theymay
even experience headaches and other physical symptoms of stress. Even if
SIMULATOR SICKNESS the visual display is excellent, the teleoperatormay 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 fallmight 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 theMoon, and 140
minutes onMars.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 example
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 operators
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 before
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

erators may have over a year of training before they can fly the vehicle. In
the case of UAVs, teleoperation permits a dangerous, important task to be
completed, but with a high cost in manpower.
According TASK to Wampler,142 teleoperation is best suited for applications
CHARACTERISTICS where:
1. The tasks are unstructured and not repetitive.
2. The task workspace cannot be engineered to permit the use of industrial
manipulators.
3. Key portions of the task intermittently require dextrousmanipulation, especially
hand-eye coordination.
4. Key portions of the task require object recognition, situational awareness,
or other advanced perception.
5. The needs of the display technology do not exceed the limitations of the
communication link (bandwidth, time delays).
6. The availability of trained personnel is not an issue.