Method and a system for position measurement of a piston rod of a hydraulic cylinder
AssigneeIndustries Mailhot Inc.
InventorsJean-Michel Ethier, Daniel Landry, Martin Dubé
Life of this patent
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Abstract
A method for determining the position of a first part moving in relation to a second part in a system, comprising forming a code on a surface of the first part or the second part, yielding an encoded surface; detecting the code on the encoded surface; decoding the code; and determining the position of the moving part from the decoding of the code; the code comprises microstructures at precisely selected positions on the surface of the encoded part; detecting the code comprises scanning the encoded surface with a sensor in conditions selected in relation to the code formed and to the encoded surface to precisely read the code on the encoded surface.
Claims20
A method for determining a position of a first part moving in relation to a second part in a system, comprising:
- forming a code on a surface of one of:
- i) the first part and ii) the second part;
- yielding an encoded surface;
- detecting the code on the encoded surface;
- decoding the code;
- and
- determining the position of the moving part from said decoding of the code;
- wherein:
- said forming the code comprises forming microstructures at precisely selected positions on the encoded surface;
- and
- said detecting the code comprises scanning the encoded surface with a sensor in conditions selected in relation to the code formed on the encoded surface and the encoded surface, the sensor being selected in relation to the code formed on the encoded surface and the encoded surface.
A method for determining a position of a piston rod reciprocating within a barrel of a linear actuator, comprising:
- forming a code on a surface of the piston rod;
- yielding an encoded surface;
- detecting the code on the encoded surface;
- decoding the code;
- and
- determining the position of the piston rod from said decoding of the code;
- wherein:
- said forming the code comprises forming microstructures at precisely selected positions on the surface of the piston rod;
- said detecting the code comprises selecting an optical sensor and acquiring images of the surface of the piston rod using the sensor;
- said decoding comprises detecting microstructures on the images and one of:
- i) determining a first position of the piston rod from said detecting of the microstructures on the images;
- ii) determining a first position of the piston rod from said detecting of the microstructures on the images and applying a first offset to the first position to obtain a second position from said detecting of the microstructures on the images;
- and ii) determining a first position of the piston rod from said detecting of the microstructures on the images;
- applying a first offset to the first position to obtain a second position from said detecting of the microstructures on the images;
- and applying a second offset to the second position to obtain a third position from said detecting of the microstructures on the images;
- the second offset being determined when the piston is in a fully retracted position.
Dependencies are inferred from the claim text.