High-order hybrid actuator controller

• US 20080174900A1
• Filed: 01/24/2007
• Published: 07/24/2008
• Est. Priority Date: 01/24/2007
• Status: Active Grant

• Current Assignee: Maxtor Corporation (Seagate Technology Holdings Plc)
• Original Assignee: Maxtor Corporation (Seagate Technology Holdings Plc)
• Inventors: Hein, Travis, Luo, Jihao, Abrishamchian, Mirmehdi L.
• Granted Patent: US 7,489,472 B2
• Time in Patent Office: Days
• US Class Current: 360/71
• CPC Class Codes: G11B 5/5521 across disk tracks spiral track following G11B5/596
• CPC Class Codes: G11B 5/59616 Synchronisation; Clocking G11B5/59622 takes precedence

Abstract

A method of providing a control output by selecting a controller to an actuator is discussed. A first controller having an estimator-compensator architecture is selected if the actuator is in a settle stage. A second controller having an architecture other than that of the first controller is selected when the actuator is in a track follow stage. The control output is provided from the selected controller to the actuator. The control output is indicative of the control signal.

Claims

1. A method, comprising:

selecting an actuator controller, including;

responsive to the actuator being in a settle stage, selecting a first controller having an estimator-compensator architecture;

responsive to the actuator being in a track follow stage, selecting a second controller having an architecture other than that of the first controller; and

providing a control output, which is indicative of the control signal, from the selected controller to the actuator.

2. The method of claim 1, wherein the step of selecting a second controller includes selecting a controller including an infinite impulse response filter having an integrator in parallel.

3. The method of claim 1 wherein the settle stage includes an early settle stage and a late settle stage and wherein step of selecting the controller further comprises:

responsive to the actuator being in the early settle stage, selecting the first controller; and

responsive to the actuator being in the late settle stage, selecting the second controller.

4. The method of claim 1 and further comprising:

providing a transition from the first controller to the second controller.

5. The method of claim 4, wherein the step of providing the transition from the first controller to the second controller comprises:

prior to selecting the second controller, receiving the control signal at the second controller and a bias term provided by the first controller to initialize the second controller.

6. The method of claim 5, wherein the step of selecting the second controller includes:

terminating the reception of the bias term provided by the first controller after the second controller has been initialized.

7. The method of claim 1, wherein the step of selecting the controller further comprises:

responsive to the actuator being in a seek stage, selecting a third controller having an architecture other than that of either of the first and second controllers.

8. The method of claim 7, wherein the step of selecting the controller further comprises:

responsive to the actuator transitioning from the seek stage to the settle stage, providing a transition between the third controller and the first controller, including aligning the first controller with a phase plane established by the third controller.

9. A method, comprising:

providing an output signal from a first controller, having an estimator-compensator architecture, to an actuator;

receiving a control signal indicative of a desired position of the actuator and a feedback signal indicative of an actual position of the actuator; and

responsive to the control signal and the feedback signal, transitioning, from the first controller to a second controller having an architecture other than the estimator-compensator architecture so that the output signal is provided by the second controller.

10. The method of claim 9, wherein the step of transitioning from the first controller to the second controller comprises:

providing the control signal to the second controller for a period of time while providing the output signal from the first controller.

11. The method of claim 9, wherein the second controller includes an integrator and wherein the step of transitioning from the first controller to the second controller comprises:

providing a momentary biasing signal from the first controller to the integrator.

12. The method of claim 9, and further comprising:

responsive to the control signal and the feedback signal, transitioning, based upon a difference between the desired position and the actual position of the actuator from the second controller to a third controller having an architecture other than an estimator-compensator architecture.

13. The method of claim 12, wherein the architectures of the second and third controllers each include a multi-stage infinite impulse filter and wherein the transition between the second controller and the third controller comprises:

matching gains between the second controller and the third controller.

14. The method of claim 9, and further comprising:

providing an output signal from a non-linear controller to an actuator;

receiving a control signal indicative of a desired position of the actuator and a feedback signal indicative of an actual position of the actuator in response to the output signal provided to the non-linear controller; and

transitioning, based upon a difference between the desired position and the actual position of the actuator from the non-linear controller to the first controller.

15. An apparatus, comprising:

an actuator; and

an actuator controller operably coupled to the actuator with a controller architecture including;

a first controller having an estimator-compensator architecture; and

a second controller having an architecture other than an estimator-compensator;

wherein the actuator controller is configured to select one of the first and second controllers to provide an output to the actuator.

16. The apparatus of claim 15, wherein the second controller includes an infinite impulse response (IIR) filter and an integrator in parallel with the IIR filter.

17. The apparatus of claim 16, wherein IIR filter of the second controller comprises at least an eighth order filter.

18. The apparatus of claim 15, wherein the second controller is configured to receive an initializing input from the first controller that is indicative of a bias estimator of the first linear controller.

19. The apparatus of claim 15, wherein the second controller is configured to function independently of the first controller.

20. The apparatus of claim 15, wherein the controller architecture further comprises:

a third controller, wherein the first and second controllers are linear controllers and the third controller is a non-linear controller.