Page 70 - Concise Encyclopedia of Robotics

Contact Sensor
On the flat plane of a floor, the location of the robot can be denoted in
two-dimensional (2-D) coordinates. In the Cartesian system described
above, these are x and y. If the attitude nevertheless requires that p, r, and
w each be specified, the C-space requires five degrees of freedom: x, y, p,
r, and w. However, p, r, and w may not all be important in the 2-D case.
This could reduce the number of degrees of freedom in the C-space still
further. Compare WORK ENVELOPE and WORK ENVIRONMENT.
See also CARTESIAN COORDINATE GEOMETRY, PITCH, ROLL, and YAW.
CONTACT SENSOR
A contact sensor is a device that detects objects, obstructions, or barriers
by means of direct physical contact. Contact sensors can also be used to
measure applied force or torque. In robotics, such devices include
“whiskers” and pressure sensors.
Simplicity is the main asset of contact sensing when used to determine
the presence or absence of an object. In order to measure force or torque
accurately, especially when such force or torque must be regulated, a
closed-loop system is required.
See also CLOSED-LOOP CONTROL, CLOSED-LOOP SYSTEM, FEEDBACK, and PRESSURE SENSING.
CONTEXT
Context is the environment in which a word is used. It is important in
speech recognition systems, such as those used in personal or security
robots designed to respond to spoken commands.
Everyone has heard the expression “out of context.” When a word is
used out of context, it results in a phrase or sentence that does not make
sense. Worse yet, it might mean something not intended. When a word is
taken out of context, the phrase or sentence is technically all right, but it
is interpreted as nonsense, or in the wrong way.
In order to interpret and respond to spoken statements properly,a com-
puter or robot with artificial intelligence must know the context in which
each word is used. Humans have an innate sense of context; machines do
not. This makes the design and programming of effective speech recogni-
tion systems an extremely sophisticated business.
See also PROSODIC FEATURES and SPEECH RECOGNITION.
CONTINUOUS ASSISTANCE
See SHARED CONTROL.

CONTINUOUS-PATH MOTION
A robot arm can move smoothly or in discrete steps. Smooth-moving
robot manipulators employ continuous-path motion.

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