31-10-2009, 04:48 PM
A control device for controlling displacement of a magnetically supported moving member according to a command, comprising:
a feedback circuit for detecting the displacement of the moving member to control the moving member to ensure stability and robustness of the magnetic support in response to the detected displacement, the feedback circuit comprising a closed loop composed of a displacement detector receptive of an output from a displacement sensor, an integral compensator coupled to the displacement sensor, a phase advancing compensator coupled to the integral compensator, and an electrical power amplifier coupled to the phase advancing compensator for effecting the magnetic support; and a feedforward circuit having an input terminal receptive of a command and an output terminal connected to the feedback circuit, and cooperative with the feedback circuit without disturbing the stability and robustness of the magnetic support for controlling the displacement of the moving member according to the command.
2. A control device according to claim 1; wherein the feedforward circuit has an output terminal connected to an input port of the electric power amplifier.
3. A control device according to claim 1; wherein the feedforward circuit comprises a low-pass filter connected to the input terminal, a high-pass filter connected to the input terminal, a compensative filter for effecting compensation of an output of the low-pass filter, a gain regulator for regulating a gain of an output of the high-pass filter, and a differential amplifier for differentially processing the outputs from the low-pass and high-pass filters to each other.
4. A control device according to claim 3; wherein the low-pass filter has a transfer function including a polynomial denominator preset according to desired response characteristic to the command, and the high-pass filter has another transfer function including another polynomial denominator having coefficients identical to those of the polynomial denominator of the transfer function of the low-pass filter.
5. A control system for controlling displacement of a movable member supported by magnetic support means, comprising: feedback control means for stabilizing the movable member in response to a displacement thereof caused by an undesired disturbance, the feedback control means comprising means for sensing a displacement of the movable member and for producing an output signal representative thereof, and compensating means receptive of the output signal for applying a compensating signal to the magnetic support means to stabilize the movable member; and feedforward control means responsive to an input command for controlling the displacement of the movable member without disturbing the stability thereof, the feedforward control means comprising input means receptive of the input command for producing a displacement signal corresponding thereto, the input means comprising a low-pass filter and a high-pass filter each receptive of the input command, and output means for combining the displacement signal with at least one of the output signal and the compensating signal of the feedback control means for receipt by the compensating means and the magnetic support means, respectively, the output means comprising means for combining an output signal from the low-pass filter with the output signal form the sensing means and for combining the difference between an output signal from the high-pass filter and the output signal from the low-pass filter with the compensating signal.
6. The control system according to claim 5, wherein the feedback control means comprises a closed loop including the sensing means and the compensating means.
7. The control system according to claim 5; wherein the input means comprises a compensative filter for effecting compensation of an output of the low-pass filter, a gain regulator for regulating a gain of an output of the high-pass filter, and a differential amplifier for differentially processing the outputs from the low-pass and high-pass filter with respect to each other.
8. The control system according to claim 7; wherein the low-pass filter has a transfer function including a polynomial denominator preset according to a desired response characteristic to the input command, and the high-pass filter has another transfer function including another polynomial denominator having coefficients identical to those of the polynomial denominator of the transfer function of the low-pass filter
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http://scribddoc/7749477/Magnetic-Bearing-and-Bearing-Less-DrivesAchiba-Et-Al
a feedback circuit for detecting the displacement of the moving member to control the moving member to ensure stability and robustness of the magnetic support in response to the detected displacement, the feedback circuit comprising a closed loop composed of a displacement detector receptive of an output from a displacement sensor, an integral compensator coupled to the displacement sensor, a phase advancing compensator coupled to the integral compensator, and an electrical power amplifier coupled to the phase advancing compensator for effecting the magnetic support; and a feedforward circuit having an input terminal receptive of a command and an output terminal connected to the feedback circuit, and cooperative with the feedback circuit without disturbing the stability and robustness of the magnetic support for controlling the displacement of the moving member according to the command.
2. A control device according to claim 1; wherein the feedforward circuit has an output terminal connected to an input port of the electric power amplifier.
3. A control device according to claim 1; wherein the feedforward circuit comprises a low-pass filter connected to the input terminal, a high-pass filter connected to the input terminal, a compensative filter for effecting compensation of an output of the low-pass filter, a gain regulator for regulating a gain of an output of the high-pass filter, and a differential amplifier for differentially processing the outputs from the low-pass and high-pass filters to each other.
4. A control device according to claim 3; wherein the low-pass filter has a transfer function including a polynomial denominator preset according to desired response characteristic to the command, and the high-pass filter has another transfer function including another polynomial denominator having coefficients identical to those of the polynomial denominator of the transfer function of the low-pass filter.
5. A control system for controlling displacement of a movable member supported by magnetic support means, comprising: feedback control means for stabilizing the movable member in response to a displacement thereof caused by an undesired disturbance, the feedback control means comprising means for sensing a displacement of the movable member and for producing an output signal representative thereof, and compensating means receptive of the output signal for applying a compensating signal to the magnetic support means to stabilize the movable member; and feedforward control means responsive to an input command for controlling the displacement of the movable member without disturbing the stability thereof, the feedforward control means comprising input means receptive of the input command for producing a displacement signal corresponding thereto, the input means comprising a low-pass filter and a high-pass filter each receptive of the input command, and output means for combining the displacement signal with at least one of the output signal and the compensating signal of the feedback control means for receipt by the compensating means and the magnetic support means, respectively, the output means comprising means for combining an output signal from the low-pass filter with the output signal form the sensing means and for combining the difference between an output signal from the high-pass filter and the output signal from the low-pass filter with the compensating signal.
6. The control system according to claim 5, wherein the feedback control means comprises a closed loop including the sensing means and the compensating means.
7. The control system according to claim 5; wherein the input means comprises a compensative filter for effecting compensation of an output of the low-pass filter, a gain regulator for regulating a gain of an output of the high-pass filter, and a differential amplifier for differentially processing the outputs from the low-pass and high-pass filter with respect to each other.
8. The control system according to claim 7; wherein the low-pass filter has a transfer function including a polynomial denominator preset according to a desired response characteristic to the input command, and the high-pass filter has another transfer function including another polynomial denominator having coefficients identical to those of the polynomial denominator of the transfer function of the low-pass filter
use this links to get it
http://scribddoc/7749477/Magnetic-Bearing-and-Bearing-Less-DrivesAchiba-Et-Al
