Page 335 - Concise Encyclopedia of Robotics

Transducer
Limitations
One potential problem with track drives is that the track can work its way
off the wheels. The chances of this are reduced by proper wheel and track
design. The inside surface of the track can have grooves, into which the
wheels fit; or the inside of the track can have lip edges. The track must be
wrapped snugly around the wheels. Some provision must be made to
compensate for expansion and contraction of the belt with extreme
changes in temperature.
Another problem with track drive is that the wheels might slip around
inside the track, without the track following along. This is especially likely
when the robot is climbing a steep slope. The machine will sit still or roll
backwards despite the fact that its wheels are turning forwards. This can
be prevented by using wheels with teeth that fit in notches on the inside
of the track. The track then resembles a gear-driven conveyor belt.
On smooth surfaces, track drives are usually not needed. If a surface is
extremely rugged, robot legs or tri-star wheel locomotion generally work
better than wheels or track drives.
See also ADAPTIVE SUSPENSION VEHICLE, ROBOT LEG, TRI-STAR WHEEL LOCOMOTION, and
WHEEL-DRIVE LOCOMOTION.
TRANSDUCER
A transducer is a device that converts one form of energy or disturbance into
another. In electronics, transducers convert alternating or direct electric
current into sound, light, heat, radio waves, or other forms. Transducers
also convert sound, light, heat, radio waves, or other energy forms into
alternating or direct electric current.
Common examples of electrical and electronic transducers include
buzzers, speakers, microphones, piezoelectric crystals, light-emitting
and infrared-emitting diodes, photocells, radio antennas, and many
other devices.
In robotics, transducers are used extensively. For details on specific
devices and processes, see BACK PRESSURE SENSOR, CAPACITIVE PROXIMITY SENSING,
CHARGE-COUPLED DEVICE, CLINOMETER, DISTANCE MEASUREMENT, DISPLACEMENT TRANSDUCER,
DYNAMIC TRANSDUCER, ELASTOMER, ELECTRIC EYE, ELECTROMECHANICAL TRANSDUCER, ELECTRO-
STATIC TRANSDUCER, ERROR-SENSING CIRCUIT, FLUXGATE MAGNETOMETER, JOINT FORCE SENSOR,
ODOMETRY, OPTICAL CHARACTER RECOGNITION, OPTICAL ENCODER, PASSIVE TRANSPONDER, PHO-
TOELECTRIC PROXIMITY SENSING, POSITION SENSING, PRESSURE SENSING, PROPRIOCEPTOR,
PROXIMITY SENSING, RANGE SENSING AND PLOTTING, SMOKE DETECTION, SONAR, SOUND TRANS-
DUCER, TACTILE SENSING, TEMPERATURE SENSING, TEXTURE SENSING, VISION SYSTEM, and
WRIST-FORCE SENSOR.

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