Page 260 - Concise Encyclopedia of Robotics

Proximity Sensing
protects against disease, treats the machine as a deadly virus or bacteria,
and attempts to destroy it. This puts life-threatening stress on the body. To
keep this from happening, doctors sometimes give drugs to suppress the
action of the immune system. However, this can make the person more
susceptible to diseases such as pneumonia and various viral infections.
Prostheses have not yet been developed that have refined tactile sense.
Primitive texture sensing might be developed, but will it ever be as discern-
ing as the real sense of touch? This depends on whether electronic circuits
can duplicate the complex impulses that travel through living nerves.
Put a penny and a dime in your pocket. Reach in and, by touch alone,
figure out which is which. This is easy; the dime has a ridged edge, but the
penny’s edge is smooth. This data goes from your fingers to your brain as
nerve impulses. Can these impulses be duplicated by electromechanical
transducers? Many researchers think so, just as Alexander Graham Bell
believed that voice waveforms could be duplicated by electronic devices.
See also BIOMECHANISM and BIOMECHATRONICS.
PROXIMITY SENSING
Proximity sensing is the ability of a robot to tell when it is near an object,
or when something is near it. This sense keeps a robot from running
into things. It can also be used to measure the distance from a robot to
some object.
Basic principle
Most proximity sensors work the same way: the output of a displacement
transducer varies with the distance to some object. This can take either of
two forms,as shown in the graphs.At left,the sensor output decreases as the
distance gets larger.At right,the sensor output rises with increasing distance.

Output decreases
Sensor output Sensor output Output increases
with distance

with distance

Distance to object Distance to object
Proximity sensing

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