Page 299 - Concise Encyclopedia of Robotics

Shared Control
cook a meal. A set of servomechanisms, including associated circuits and
hardware, and intended for a specific task, constitutes a servo system.
Servo systems do precise, often repetitive, mechanical chores.
A computer can control a servo system made up of many servomech-
anisms. For example, an unmanned robotic warplane (also known as a
drone) can be programmed to take off, fly a mission, return, and land.
Servo systems can be programmed to do assembly-line work and other
tasks that involve repetitive movement, precision, and endurance.
A servo robot is a robot whose movement is programmed into a com-
puter. The robot follows the instructions given by the program, and
carries out precise motions on that basis. Servo robots can be categorized
according to the way they move. In continuous-path motion, the robot
mechanism can stop anywhere along its path. In point-to-point motion, it
can stop only at specific points in its path. Servo robots can be easily pro-
grammed and reprogrammed. This might be done by exchanging
diskettes, by manual data entry, or by more exotic methods such as a
teach box. Compare SELSYN, STEPPER MOTOR, and SYNCHRO.
See also CLOSED-LOOP SYSTEM, CONTINUOUS-PATH MOTION, OPEN-LOOP SYSTEM, PER-
SONAL ROBOT, POINT-TO-POINT MOTION, and TEACH BOX.
SHAPE-SHIFTING ROBOT
See POLYMORPHIC ROBOT.
SHARED CONTROL
Shared control, also called continuous assistance, is a form of robotic remote
control in a system that employs teleoperation. The operator oversees the
execution of a complex task such as repairing a satellite on a Space Shuttle
mission.The human operator can delegate some portions of the task to the
robot, but supervision must be maintained at all times. If necessary,
the operator can intervene and take control of (assist) the robot.
Shared control has assets in certain situations, especially critical
missions. The human operator constantly monitors the progress of the
machine. The system can contend with sudden, unforeseen changes in
the work environment.
Shared control has limitations. It is difficult for a single operator to
oversee the operation of more than one robot at a time. Latency, or the
time lag caused by signal propagation delays, makes two-way teleopera-
tion difficult if the operator and the robot are separated by a great dis-
tance. Shared control is impractical, for example, in the teleoperation of
a robot on the other side of the solar system. Still another problem is
that large signal bandwidth is required during those periods when the
human operator must take direct control of the robot. In scenarios such as

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