Digital closed loop proportional hydraulic pressure controller

Patent metadata

Field	Value
Publication number	US-9387522-B2
Application number	US-201414225574-A
Country	US
Kind code	B2
Filing date	Mar 26, 2014
Priority date	Feb 1, 2008
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

A digitally controlled current to pressure converter (CPC) and method of controlling same is provided. The method of controlling includes the step of periodically imparting symmetrically-opposed movement of a control valve of the CPC to loosen and flush accumulated silt therefrom. More particularly, the method may include the step of periodically introducing a small-amplitude symmetrically-opposed impulse to a controller that actuates a hydraulic control shaft of a three-way rotary valve. Also provided is a method of preventing malfunction due to faulty input or feedback signals received by the CPC, and a method of detecting the health status of multiple CPCs when used in a redundant configuration.

First claim

What is claimed is:

1. A method of preventing malfunction of a current-to-pressure converter (CPC), comprising the step of periodically imparting symmetrically-opposed movement of a control valve of the CPC to loosen and flush accumulated silt therefrom, wherein the step of periodically imparting symmetrically-opposed movement of a control valve comprises the step of periodically introducing a small-amplitude symmetrically-opposed impulse to a controller that actuates a hydraulic control shaft of a three-way rotary valve, wherein the step of periodically introducing a small-amplitude symmetrically-opposed impulse to a controller comprises periodically introducing a small-amplitude symmetrically-opposed impulse to a digital controller.

2. The method of preventing malfunction according to claim 1 , further comprising the step of adjusting a period of the small-amplitude symmetrically-opposed impulse.

3. The method of preventing malfunction according to claim 1 , further comprising the steps of:
detecting a drive current level required to actuate the hydraulic control shaft;
increasing a frequency at which the small-amplitude symmetrically-opposed impulse is
introduced to the controller if the drive current is detected at a level that indicates accumulated silt; and
decreasing the frequency at which the small-amplitude symmetrically-opposed impulse is introduced to the controller if the drive current is detected at a level that does not indicate accumulated silt.

4. The method of preventing malfunction according to claim 1 , further comprising the step of configuring the controller such that a user can set the period of the small-amplitude symmetrically-opposed impulse.

5. The method of preventing malfunction according to claim 1 , wherein the step of periodically introducing a small-amplitude symmetrically-opposed impulse to a controller that actuates a hydraulic control shaft of a three-way rotary valve comprises periodically introducing a small-amplitude symmetrically-opposed impulse to a controller that actuates a hydraulic control shaft via a rotary actuator coupled to the three-way rotary valve.

6. The method of preventing malfunction according to claim 5 , wherein the rotary actuator is a limited angle torque rotary actuator.

7. The method of preventing malfunction according to claim 1 , further comprising the step of diagnosing input signals to the controller to determine reasonableness of the input signal with respect to their use in controlling a position of the 3-way rotary valve.

8. The method of preventing malfunction according to claim 1 , wherein the step of periodically introducing a small-amplitude symmetrically-opposed impulse to a controller comprises periodically introducing a symmetrically-balanced impulse so as not to perturb components controlled by the CPC.

9. The method of claim 1 , wherein small-amplitude symmetrically-opposed impulse has an impulse amplitude of 5% or less.

10. The method of claim 9 , wherein the small-amplitude symmetrically-opposed impulse has an impulse amplitude of approximately 1%.

11. The method of claim 1 , wherein the small-amplitude symmetrically-opposed impulse has an impulse duration of between 4 milliseconds to one hundred milliseconds.

12. The method of claim 11 , wherein the small-amplitude symmetrically-opposed impulse has an impulse duration of approximately 40 milliseconds.

Assignees

• Greeb Kevin E
• Woodward Inc

Inventors

• Greeb Kevin E

Classifications

• G05D16/202 Primary

  actuated by an electric motor · CPC title

• Y10T137/5762

  With leakage or drip collecting · CPC title

• Y10T137/7761

  Electrically actuated valve · CPC title

• B08B9/0326 Primary

  Using pulsations · CPC title

• Y10T137/0318

  Processes · CPC title