Robot Mechanisms and Mechanical Devices Illustrated - Profe Saul

Chapter 1 Motor and Motion Control Systems 11
or cams. Electronic gearing is the control by software of one or more
axes to impart motion to a load, tool, or end effector that simulates the
speed changes that can be performed by actual gears. Electronic camming
is the control by software of one or more axes to impart a motion to
a load, tool, or end effector that simulates the motion changes that are
typically performed by actual cams.
Mechanical Components
The mechanical components in a motion control system can be more
influential in the design of the system than the electronic circuitry used
to control it. Product flow and throughput, human operator requirements,
and maintenance issues help to determine the mechanics, which in turn
influence the motion controller and software requirements.
Mechanical actuators convert a motor’s rotary motion into linear
motion. Mechanical methods for accomplishing this include the use of
leadscrews, shown in Figure 1-10, ballscrews, shown in Figure 1-11,
worm-drive gearing, shown in Figure 1-12, and belt, cable, or chain
drives. Method selection is based on the relative costs of the alternatives
and consideration for the possible effects of backlash. All actuators have
finite levels of torsional and axial stiffness that can affect the system’s
frequency response characteristics.
Figure 1-10 Leadscrew drive: As
the leadscrew rotates, the load is
translated in the axial direction of
the screw.