Geometrical instruments – Distance measuring – Scale reading position sensor
Patent
1993-08-05
1995-10-10
Will, Thomas B.
Geometrical instruments
Distance measuring
Scale reading position sensor
33706, G01B 1100
Patent
active
054560209
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method for the determination of the position of a position-control element relative to a reference body.
Such a method serves, for example for detecting in the control of measuring and manufacturing machines distances between longitudinally displaceable objects such as measuring heads and gripping or mounting arms. In this connection, the accuracy with which such distances can be determined is of decisive importance for the manufacturing accuracy of the automatic machine.
A method is already known from DE-OS 39 09 856 that permits a high measuring accuracy independently of an exact guidance of the scanner. In this connection, three graduations of a scale are analyzed by a scanner. With two graduations, the angle of projection formed between a scanner location and said graduations would still be dependent upon the distance by which the scanner location is disposed above the graduations, and how far it is displaced laterally. With three graduations, it is possible to exactly determine the scanner location via the additional angle of projection between the scanner location, said additional graduation and one of the other graduations, because for a combination of two angles of combination, only one single location exists in which the scanner location can be.
The invention has as an object the creation of the preconditions which, in addition to measurements of the position on one axis of the scale and perpendicular to the latter, permit the detection of additional position parameters between a position-control element relative to a reference body.
With the method according to the invention, this object is achieved.
Such position parameters include an additional coordinate direction and/or inclinations or angles of inclination around one or several coordinate axes. The invention is based on the consideration that it is possible through analysis of two angles of projection to determine the distance between a scanner location and the scale. Now, if such measurement of the distance is carried out in two different locations, it is possible to analyze an additional coordinate direction, taking into account the mutual alignment of the optical axes, and to deduce the inclination of the scale relative to a straight line extending through the two scanner locations, allowing for the mutual distance between the scanner locations.
Now, based on said consideration it is possible to determine any angle of inclination around a coordinate axis. If the angle around only one coordinate axis is to be analyzed, it suffices to determine on a scale arranged perpendicular to said coordinate axis the distances between the scale and two scanner locations. With angles of inclination in two coordinate directions, the distances between two scales and two scanner locations in each case are determined accordingly. It is possible also to expand the distance measurement in three coordinate directions; in this way, it is possible then to detect all three angles of inclination around the coordinate directions.
A simplified application makes provision that the graduations and angles of projection to be analyzed are determined by scanners with equally aligned optical axes. In this connection, said graduations and angles of projection can be analyzed by a total of two scanners that are both associated with the same scale.
In this way, it is possible to determine in addition to the coordinates of two coordinate axes also the angle of inclination around a third coordinate axis.
Another simplified application makes provision for analyzing the graduations disposed on an additional scale that is aligned parallel with the first scale. The graduations and angles of projection can be analyzed by a total of two scanners, of which each one is associated with a scale.
Said application makes it possible to determine both the coordinates of two coordinate axes and the angles of inclination around one of said coordinate axis and a third coordinate axis.
If another scanner is used additionally that is associated with one of said scales,
REFERENCES:
patent: 2875524 (1959-03-01), Bower et al.
patent: 4461083 (1984-07-01), Ernst
patent: 4602463 (1986-07-01), Ernst
patent: 4626100 (1986-12-01), Johnson
patent: 4628609 (1986-12-01), Rieder
patent: 4654527 (1987-03-01), Schmitt
Patent Abstracts of Japan, vol. 11, No. 261, Aug. 25, 1987.
Bennett G. Bradley
E.M.S. Technik GmbH
Will Thomas B.
LandOfFree
Method and sensor for the determination of the position of a pos does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and sensor for the determination of the position of a pos, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and sensor for the determination of the position of a pos will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2303158