Aerotech SOLOIST Hardware Manual page 98

Glossary of Terms
A-2
Ball Screw
Ball Screw Lead
Bandwidth
Baud Rate
BCD
Bearing
Bidirectional
Repeatability
CAM Profile
Cantilevered Load
Closed Loop
CNC
Coefficient of Friction
Cogging
Commutation
Soloist Hardware Manual
A precision device for translating rotary motion into
linear motion. A lead screw is a low-cost lower
performance device performing the same function. Unit
consists of an externally threaded screw and an internally
threaded ball nut.
The linear distance a carriage will travel for one
revolution of the ball screw (lead screw).
A measurement, expressed in frequency (hertz), of the
range which an amplifier or motor can respond to an
input command from DC to -3dB on a frequency sweep.
The number of bits transmitted per second on a serial
communication channel such as RS-232 or modem.
Binary Coded Decimal - A number system using four
bits to represent 0-F (15).
A support mechanism allowing relative motion between
two surfaces loaded against each other. This can be a
rotary ball bearing, linear slide bearing, or air bearing
(zero friction).
See Repeatability.
A technique used to perform nonlinear motion that is
electronically similar to the motion achieved with
mechanical cams.
A load not symmetrically mounted on a stage.
A broad term relating to any system where the output is
measured and compared to the input. Output is adjusted
to reach the desired condition.
Computer Numerical Control. A computer-based motion
control device programmable in numerical word address
format.
Defined as the ratio of the force required to move a given
load to the magnitude of that load.
Nonuniform angular/linear velocity. Cogging appears as
a jerkiness, especially at low speeds, and is due to
magnetic poles attracting to steel laminations.
The action of steering currents to the proper motor
phases to produce optimum motor torque/force. In brush-
type motors, commutation is done electromechanically
via the brushes and commutator. A brushless motor is
electronically commutated using a position feedback
device such as an encoder or Hall effect devices.
Stepping motors are electronically commutated without
feedback in an open-loop fashion.
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