Robot Mechanisms and Mechanical Devices Illustrated - Profe Saul

12 Chapter 1 Motor and Motion Control Systems
Figure 1-11 Ballscrew drive: Ballscrews use recirculating
balls to reduce friction and gain higher efficiency than conventional
leadscrews.
Figure 1-12 Worm-drive systems can provide high speed
and high torque.
Linear guides or stages constrain a translating load to a single degree
of freedom. The linear stage supports the mass of the load to be actuated
and assures smooth, straight-line motion while minimizing friction. A
common example of a linear stage is a ballscrew-driven single-axis
stage, illustrated in Figure 1-13. The motor turns the ballscrew, and its
rotary motion is translated into the linear motion that moves the carriage
and load by the stage’s bolt nut. The bearing ways act as linear guides.
As shown in Figure 1-7, these stages can be equipped with sensors such
as a rotary or linear encoder or a laser interferometer for feedback.
A ballscrew-driven single-axis stage with a rotary encoder coupled to
the motor shaft provides an indirect measurement. This method ignores
Figure 1-13 Ballscrew-driven
single-axis slide mechanism translates
rotary motion into linear
motion.