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US 11,408,449 B2Granted
Dithering hydraulic valves to mitigate static friction
AssigneeTopcon Positioning Systems, Inc.
InventorVernon Joseph Brabec
Life of this patent
Estimating the term…
Abstract
A method and apparatus for dithering hydraulic valves to mitigate static friction (“stiction”) associated with the hydraulic valves. A first hydraulic valve and a second hydraulic valve are dithered to mitigate stiction associated with those valves. The dithering of the first and second hydraulic valves also cause dithering of a main hydraulic valve associated with the first and second hydraulic valves. Accordingly, stiction of three hydraulic valves of a hydraulic system is mitigated.
Claims18
A method comprising:
- dithering a first hydraulic valve to produce a first periodically varying hydraulic fluid pressure applied to a first input of a second hydraulic valve;
- and
- dithering a third hydraulic valve to produce a second periodically varying hydraulic fluid pressure 180 degrees out of phase with the first periodically varying hydraulic fluid pressure and applied to a second input of the second hydraulic valve,
- wherein the first periodically varying hydraulic fluid pressure and the second periodically varying fluid pressure applied to the first input and the second input of the second hydraulic valve cause the second hydraulic valve to dither, and the dithering of the second hydraulic valve causes hydraulic fluid pressure to be applied to a first input of a hydraulic cylinder and a second input of the hydraulic cylinder, wherein the hydraulic fluid pressure applied is a value lower than a value required to actuate the hydraulic cylinder.
1 more element
An apparatus comprising:
- a first hydraulic valve having a first output;
- a second hydraulic valve having a second output;
- a third hydraulic valve having a first input connected to the first output and a second input connected to the second output;
- and
- a controller in communication with the first hydraulic valve and the second hydraulic valve, the controller configured to perform operations comprising:
- dithering the first hydraulic valve to produce a first periodically varying hydraulic fluid pressure applied to the first input of the third hydraulic valve;
- and
- dithering the second hydraulic valve to produce a second periodically varying hydraulic fluid pressure applied to the second input of the third hydraulic valve,
- wherein the first periodically varying hydraulic fluid pressure and the second periodically varying fluid pressure applied to the first input and the second input of the third hydraulic valve are 180 degrees out of phase and cause the third hydraulic valve to dither, and the dithering of the second hydraulic valve causes hydraulic fluid pressure to be applied to a first input of a hydraulic cylinder and a second input of the hydraulic cylinder, wherein the hydraulic fluid pressure applied is a value lower than a value required to actuate the hydraulic cylinder.
6 more elements
An excavator comprising:
- a hydraulic cylinder associated with an implement member of the excavator;
- a first hydraulic valve having a first output;
- a second hydraulic valve having a second output;
- a third hydraulic valve having a first input connected to the first output, a second input connected to the second output, a third output connected to a first side of the hydraulic cylinder and a fourth output connected to a second side of the hydraulic cylinder;
- and
- a controller in communication with the first hydraulic valve and the second hydraulic valve, the controller configured to perform operations comprising:
- dithering the first hydraulic valve to produce a first periodically varying hydraulic fluid pressure applied to the first input of the third hydraulic valve;
- and
- dithering the second hydraulic valve to produce a second periodically varying hydraulic fluid pressure applied to the second input of the third hydraulic valve,
- wherein the first periodically varying hydraulic fluid pressure and the second periodically varying fluid pressure applied to the first input and the second input of the third hydraulic valve are 180 degrees out of phase and cause the third hydraulic valve to dither.
7 more elements
Dependencies are inferred from the claim text.