LSA-10A-30-D-130 Technical Document
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2-3-1 Response during Rectangular Wave Drive
The responses of the rectangular or trapezoid wave operations are important for utilizing the positioning
operation. Generally, the trapezoid wave drive settles easier and is better for applications of fluctuating
amplitudes, than the rectangular wave drive.
Rectangular wave drive is showed as an example as follows, and the conditions need to be considered are
discussed.
♦
Rectangular Wave Drive Step Response Characteristic (example observed by oscilloscope)
[1] Emphasized Adjustment Amplitude (Unit: [°])
This indicates the optimally adjusted amplitudes during adjustment. Generally, the amplitudes with the
most often used frequency are taken as the emphasized adjustment amplitudes. In case of large
amplitude operation, the command waves of step inputs (stacking small amplitudes) or trapezoid wave
inputs, etc. are utilized
・
Response and stability are well balanced and optimal when the actual drive amplitude is equal to the
adjustment amplitude.
・
The gain can be raised and the Settling Time decreases as the size of the emphasized adjustment
amplitude decreases.
・
If the amplitudes are not constant, the largest amplitude has to be the emphasized adjustment
amplitude.
・
If a command with an amplitude larger than the emphasized adjustment amplitude is input, longer time
is necessary for setting after reaching the command position. On the other hand, when a command with
an amplitude smaller than the emphasized adjustment amplitude is input, the setting time will be
identical to the setting time when the emphasized adjustment amplitude is input.
[2] Convergence Criteria (Unit: [°] or [arc-sec])
This indicates the width of the allowable positioning error that is for setting judgment for the commanded
position. Generally, necessary and sufficient conditions of positioning accuracy are considered as
convergence criteria. The device is adjusted to the shortest Settling Time as conditions are satisfied.
・
For quick-response operation, the convergence criteria are set broadly and the gain is adjusted high.
Although response increases, longer time is necessary till the device matches the commanded
position.
・
During accurate positioning operation, the convergence criteria are set narrowly and the gain is
adjusted low. Although response decreases, the device matches the commanded position in a short
amount of time.
・
If the Settling Time is the same, the convergence criteria can be narrowed as the size of the
Positioning Command Signal
Positioning Sensor Signal
Positioning Error Signal
[2] Convergence Criteria
[3] Settling Time
Time
Position
[1] Emphasized Adjustment
Amplitude
