Page 347 - Sensors and Control Systems in Manufacturing

Advanced Sensors in Pr ecision Manufacturing

FIGURE 6.21 Beam splitter diverts refl ections from a continuous-wave laser into a 303
CCD camera for measurement of angles of refl ection.

This difference, in turn, manifests itself as a displacement between
the swept and unswept positions, at the output end of the streak tube,
of the spot of light that represents the reflection from the target. The
output of the streak tube is focused on a CCD for measurement and
processing of the position of this spot. Three microprocessors control
the operation of SHAPES and convert the raw data required from the
angular-position and distance-measuring CCDs into the position of
the target in three dimensions.

6.20 Optoelectronic Feedback Signals for Servomotors
through Fiber Optics
In what is believed to be among its first uses to close a digital motor-
control loop, fiber-optics transmission provides immunity to noise
and rapid transmission of data. An optoelectronic system affects
closed-loop control of the shaft angle of four servomotors and could
be expanded to control as many as 16. The system includes a full-duplex
fiber-optic link (Fig. 6.22) that carries feedforward and feedback digi-
tal signals over a distance of many meters, between commercial