System and method for adjusting a pid controller in a limited rotation motor system

• US 20050162174A1
• Filed: 01/21/2005
• Published: 07/28/2005
• Est. Priority Date: 01/23/2004
• Status: Active Grant

• Current Assignee: Novanta Corporation (Novanta Inc.)
• Original Assignee: GSI Lumonics Corporation (Novanta Inc.)
• Inventors: Huang, Yuhong
• Granted Patent: US 7,190,144 B2
• Time in Patent Office: Days
• US Class Current: 324/520
• CPC Class Codes: B23K 26/04 Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
• CPC Class Codes: B23K 26/043 along the beam path, i.e. alignment of laser beam axis relative to laser beam apparatus
• CPC Class Codes: B41M 5/26 Thermography B41M5/20, B41M5/24 take precedence; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used B23K takes precedence; thermographic or photothermographic systems using noble metal compounds G03C1/494
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G05B 11/42 for obtaining a characteristic which is both proportional and time-dependent, e.g. P. I., P. I. D.
• CPC Class Codes: G05B 13/042 in which a parameter or coefficient is automatically adjusted to optimise the performance
• CPC Class Codes: Y02P 70/10 Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Abstract

An adjustment system is disclosed for adjusting a proportional, integral, derivative controller in a limited rotation motor system. The adjustment system includes a first transform unit, a second transform unit, a model identification unit, and a PID adjustment unit. The first transform unit is for receiving a first digital signal that is representative of a motor control signal, and is for providing a first frequency domain sequence that is representative of a frequency domain representation of the motor control signal. The second transform unit is for receiving a second digital signal that is representative of a position detection signal, and is for providing a second frequency domain sequence that is representative of a frequency domain representation of the position detection signal. The model identification unit is for identifying a representation of a ratio of the first and second frequency domain sequences. The PID adjustment unit is for identifying appropriate values for the coefficient k_p of a proportional unit of the system, for the coefficient k_i of an integral unit for the system, and for the coefficient k_d of a derivative unit for the system.

Claims

1. An adjustment system for adjusting a proportional, integral, derivative controller in a limited rotation motor system, said adjustment system comprising:

first transform means for receiving a first digital signal that is representative of a motor control signal, and for providing a first frequency domain sequence that is representative of a frequency domain representation of the motor control signal;

second transform means for receiving a second digital signal that is representative of a position detection signal, and for providing a second frequency domain sequence that is representative of a frequency domain representation of the position detection signal;

model identification means for identifying a representation of a ratio of the first and second frequency domain sequences; and

PID adjustment means for identifying appropriate values for the coefficient k_p of a proportional unit of the system, for the coefficient k_i of an integral unit for the system, and for the coefficient k_d of a derivative unit for the system.

2. The system as claimed in claim 1, wherein said first transform means and said second transform means each perform a Fast Fourier Transform.

3. The system as claimed in claim 1, wherein said adjustment means is coupled to the proportional, integral, derivative controller via a digital network.

4. The system as claimed in claim 1, wherein said model identification means includes best fit analysis means for identifying a known frequency response that most closely matches the ratio of the first and second frequency domain sequences.

5. The system as claimed in claim 1, wherein the ratio of the first and second frequency domain sequences is provided by the second frequency domain sequence divided by the first frequency domain sequence.

6. The system as claimed in claim 1, wherein the proportional, integral, derivative controller is a PI plus D controller.

7. The system as claimed in claim 1, wherein the proportional, integral, derivative controller is a P plus I plus D controller.

8. The system as claimed in claim 1, wherein said proportional, integral, derivative controller is employed in a limited rotation motor system.

9. A proportional, integral, derivative controller including a proportional unit, an integral unit, and a derivative unit, said controller comprising:

first transform means for receiving a first digital signal that is representative of a motor control signal, and for providing a first frequency domain sequence that is representative of a frequency domain representation of the motor control signal;

second transform means for receiving a second digital signal that is representative of a position detection signal, and for providing a second frequency domain sequence that is representative of a frequency domain representation of the position detection signal;

model identification means for identifying a representation of a ratio of the first and second frequency domain sequences; and

PID adjustment means for identifying appropriate values for the coefficient k_p of the proportional unit of the system, for the coefficient k_i of the integral unit for the system, and for the coefficient k_d of the derivative unit for the system.

11. The system as claimed in claim 10, wherein said PID adjustment means is coupled to the proportional, integral, derivative controller via a digital network.

12. The system as claimed in claim 10, wherein said model identification means includes best fit analysis means for identifying a known frequency response that most closely matches the ratio of the first and second frequency domain sequences.

13. The system as claimed in claim 10, wherein the ratio of the first and second frequency domain sequences is provided by the second frequency domain sequence divided by the first frequency domain sequence.

14. The system as claimed in claim 10, wherein the proportional, integral, derivative controller is a PI plus D controller.

15. The system as claimed in claim 10, wherein the proportional, integral, derivative controller is a P plus I plus D controller.

16. The system as claimed in claim 10, wherein said proportional, integral, derivative controller is employed in a limited rotation motor system.

17. A proportional, integral, derivative controller system include a first controller for controlling an x axis limited rotation motor, and a second controller for controlling ay axis limited rotation motor, each of said first and second controllers comprising:

first transform means for receiving a first digital signal that is representative of a motor control signal, and for providing a first frequency domain sequence that is representative of a frequency domain representation of the motor control signal;

second transform means for receiving a second digital signal that is representative of a position detection signal, and for providing a second frequency domain sequence that is representative of a frequency domain representation of the position detection signal;

model identification means for identifying a representation of a ratio of the first and second frequency domain sequences; and

PID adjustment means for identifying appropriate values for the coefficient k_p of a proportional unit of the system, for the coefficient k_i of the integral unit for the system, and for the coefficient k_d of a derivative unit for the system.

18. The system as claimed in claim 17, wherein said PID adjustment means is coupled to the proportional, integral, derivative controller via a digital network.

19. The system as claimed in claim 17, wherein said model identification means includes best fit analysis means for identifying a known frequency response that most closely matches the ratio of the first and second frequency domain sequences.

20. The system as claimed in claim 17, wherein the ratio of the first and second frequency domain sequences is provided by the second frequency domain sequence divided by the first frequency domain sequence.