PERFORMANCE IMPROVEMENT OF SIGNAL TRANSFORMATION SCHEMES FOR ULTRA-FAST SCANNING

• US 20120046762A1
• Filed: 08/18/2010
• Published: 02/23/2012
• Est. Priority Date: 08/18/2010
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Sebastian, Abu, Pantazi, Angeliki, Tuma, Tomas
• Granted Patent: US 8,401,676 B2
• Time in Patent Office: Days
• US Class Current: 700/45
• CPC Class Codes: G05B 19/41835 characterised by programme execution
• CPC Class Codes: G05B 2219/31264 Control, autonomous self learn knowledge, rearrange task, reallocate resources
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A mechanism for controlling a plant is provided. A reference signal is received at a signal transformation loop of a feedback controller. The signal transformation loop causes the reference signal to include a disturbance signal and a nominal signal. Also, the reference signal is received at a feed-forward controller, and the feed-forward controller recreates the disturbance signal that was caused by the signal transformation loop. The output of the feedback controller is input into a plant. The output of the feed-forward controller is input into the plant such that the disturbance signal is removed from the output of the feedback controller.

Claims

1. A method for controlling a plant, comprising:

receiving a reference signal at a feedback controller comprising signal transformation blocks for signal transformation;

wherein the signal transformation blocks translate signals between a first frequency domain and a second frequency domain; and

wherein the signal transformation blocks cause an output of the feedback controller to comprise a disturbance signal in addition to a nominal signal;

receiving the reference signal at a feed-forward controller;

recreating by the feed-forward controller the disturbance signal that was caused by the signal transformation blocks;

creating an input to the plant by;

adding the output of the feedback controller; and

subtracting the output of the feed-forward controller such that the disturbance signal is removed from the input to the plant; and

adding the output of the feed-forward controller to the output of the plant.

2. The method of claim 1, wherein the signal transformation blocks cause a deviation of the plant output from the reference signal and the deviation is caused by the disturbance signal.

3. The method of claim 1, wherein the output of the feed-forward controller is configured to remove a deviation of the reference signal caused by the disturbance signal.

4. The method of claim 1, wherein subtracting the output of the feed-forward controller from the output of the feedback controller such that the disturbance signal is removed from the input to the plant causes the output of the plant to be substantially identical to the reference signal.

5. The method of claim 1, wherein the output of the plant is combined with the output of feed-forward controller to form a transparent signal.

6. The method of claim 5, wherein the transparent signal is configured to make effects of the feed-forward controller transparent to a signal transformation loop.

7. The method of claim 5, further comprising inputting the transparent signal into a transformation function of the signal transformation loop, wherein the transparent signal appears normal to the transformation function.

8. The method of claim 7, wherein an output of the transformation function is input into the feedback controller.

9. A device configured for controlling a plant, comprising:

memory for storing one or more programs; and

a processor, functionally coupled to the memory, the processor being responsive to computer-executable instructions contained in the one or more programs and operative for;

receiving a reference signal at a feedback controller comprising signal transformation blocks for signal transformation;

wherein the signal transformation blocks translate signals between a first frequency domain and a second frequency domain; and

wherein the signal transformation blocks cause an output of the feedback controller to comprise a disturbance signal in addition to a nominal signal;

receiving the reference signal at a feed-forward controller;

recreating by the feed-forward controller the disturbance signal that was caused by the signal transformation blocks;

creating an input to the plant by;

adding the output of the feedback controller; and

subtracting the output of the feed-forward controller such that the disturbance signal is removed from the input to the plant; and

adding the output of the feed-forward controller to the output of the plant.

10. The device of claim 9, wherein the signal transformation blocks cause a deviation of the plant output from the reference signal and the deviation is caused by the disturbance signal.

11. The device of claim 9, wherein the output of the feed-forward controller is configured to remove a deviation of the reference signal caused by the disturbance signal.

12. The device of claim 9, wherein subtracting the output of the feed-forward controller from the output of the feedback controller such that the disturbance signal is removed from the input to the plant causes the output of the plant to be substantially identical to the reference signal.

13. The device of claim 9, wherein the output of the plant is combined with the output of feed-forward controller to form a transparent signal.

14. The device of claim 13, wherein the transparent signal is configured to make effects of the feed-forward controller transparent to the signal transformation loop.

15. The device of claim 13, further comprising inputting the transparent signal into a transformation function of the signal transformation loop, wherein the transparent signal appears normal to the transformation function.

16. The device of claim 15, wherein an output of the transformation function is input into the feedback controller.

17. A computer program product for controlling a plant, the computer program product comprising:

a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code for providing fast scanning comprising;

receiving a reference signal at a feedback controller comprising signal transformation blocks for signal transformation;

wherein the signal transformation blocks translate signals between a first frequency domain and a second frequency domain; and

wherein the signal transformation blocks cause an output of the feedback controller to comprise a disturbance signal in addition to a nominal signal;

receiving the reference signal at a feed-forward controller;

recreating by the feed-forward controller the disturbance signal that was caused by the signal transformation blocks;

creating an input to the plant by;

adding the output of the feedback controller; and

subtracting the output of the feed-forward controller such that the disturbance signal is removed from the input to the plant; and

adding the output of the feed-forward controller to the output of the plant.

18. The computer program product of claim 17, wherein the signal transformation blocks cause a deviation of the plant output from the reference signal and the deviation is caused by the disturbance signal.

19. The computer program product of claim 17, wherein the output of the feed-forward controller is configured to remove a deviation of the reference signal caused by the disturbance signal.

20. The computer program product of claim 17, wherein subtracting the output of the feed-forward controller from the output of the feedback controller such that the disturbance signal is removed from the input to the plant causes the output of the plant to be substantially identical to the reference signal.