Glossary of Servo Tuning Concepts
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The positioning error resulting from angular motion and an offset between the measuring device and the point of interest.
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The value of the offset between the measuring device and the point of interest.
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A move referenced to a known point or datum.
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A positioning coordinate reference where all positions are specified relative to a reference or“home” position.
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A servomotor with stationary windings in the stator assembly and permanent magnet rotor. AC brushless generally refers to a sinusoidally wound motor (such as BM series) to be commutated via sinusoidal current waveform. (see DC Brushless Servo)
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The change in velocity as a function of time.
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An absolute measurement defining the difference between actual and commanded position
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In reference to an encoder grating, accuracy grade is the tolerance of the placement of the graduations on the encoder scale
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American Standard Code for Information Interchange. This code assigns a number to each numeral and letter of the alphabet. Information can then be transmitted between machines as a series of binary numbers.
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Positioning error of the rotary stage in the vertical direction when the tabletop is oriented in the horizontal plane. Axial runout is defined as the total indicator reading on a spherical ball positioned 50 mm above the tabletop and centered on the axis of rotation.
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A center line about which rotation occurs.
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A component of bidirectional repeatability, it is the non-responsiveness of the system load to reversal of input command.
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A precision device for translating rotary motion into linear motion. A lead screw is a lower cost, lower performance device performing the same function. Unit consists of an externally threaded screw and an internally threaded ball nut
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The linear distance a carriage will travel for one revolution of the ball screw (lead screw).
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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.
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The number of bits transmitted per second on a serial communication channel such as RS-232 or modem.
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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).
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Repeatability is the maximum deviation from the mean (each side) when repeatedly approaching a position. Unidirectional repeatability refers to the value established by moving toward a position in the same direction. Bidirectional repeatability refers to the value established by moving toward a position in the same or opposite direction.
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A number system using four bits to represent 0-F (15).
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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.
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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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The maximum deviation from the mean (each side) when repeatedly approaching a position. Unidirectional repeatability refers to the value established by moving toward a position in the same direction. Bidirectional repeatability refers to the value established by moving toward a position in the same or opposite direction.
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Repeatability is the maximum deviation from the mean (each side) when repeatedly approaching a position. Unidirectional repeatability refers to the value established by moving toward a position in the same direction. Bidirectional repeatability refers to the value established by moving toward a position in the same or opposite direction.