Boots – shoes – and leggings
Patent
1995-06-08
1998-07-21
Elmore, Reba I.
Boots, shoes, and leggings
36416707, 36447434, 395 94, 901 47, G05B 1918, G06F 1900, G06G 764, G06G 766
Patent
active
057842825
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a method and to apparatus for identifying the position in three dimensions of a movable object such as a sensor or a tool carried, e.g. by a robot so as to be displaceable in a given three-dimensional volume or zone.
BACKGROUND OF THE INVENTION
When it is desired to know accurately the position and the orientation of a sensor or of a tool mounted on a robot, the position and the orientation of the robot or the displacement thereof cannot be established with sufficient accuracy for it to be possible to deduce therefrom by computation the position and the orientation of the sensor or of the tool, and for that purpose it is necessary to use means that are relatively very sophisticated and expensive.
For example, it is necessary to dispose around the displacement zone of the robot at least two systems for sighting a reference mark or target provided on the robot. When high accuracy is required, then use is made of theodolites, which are devices that are very expensive and difficult to operate.
SUMMARY OF THE INVENTION
A particular object of the present invention is to avoid those drawbacks of the prior art.
The present invention provides a method and apparatus for identifying the position of a movable object by triangulation, enabling great accuracy to be obtained, comparable to that which would be obtained by using theodolites, but requiring only one quite cheap sighting system.
To this end, the invention provides a method of identifying the position in three dimensions of a movable object, e.g. such as a sensor or a tool carried by a robot, the method being characterized in that it consists in swivel-mounting a photosensitive detector such as a video camera, e.g. of the CCD type, on the movable object so as to be capable of being swivelled about at least one axis on said object, using the detector to sight targets disposed at predetermined locations relative to the displacement zone of the movable object, determining the positions of the optical axis of the detector that correspond to the sighted targets, and deducing therefrom the accurate position and orientation of said movable object by triangulation.
The invention thus differs from the prior art essentially in that the aiming system is on-board the movable object, and in that it is constituted by a CCD video camera, e.g. a monochrome camera, which constitutes a device that is reliable and quite cheap, or it may optionally be constituted by a four-quadrant detector.
Advantageously, the detector is rotatable stepwise about the, or each, above-specified axis, to occupy predetermined angular positions, each of which is defined with a high degree of repeatability.
It is then possible by a prior calibration operation to define accurately the direction of the optical axis of the detector in each of the predetermined angular positions thereof.
It is also possible by means of another calibration operation to determine accurately the parameters specific to the means for swivelling the detector.
The invention also provides apparatus for identifying the position in three dimensions of a movable object, e.g. such as a sensor or a tool carried by a robot, the apparatus being characterized in that it comprises a photosensitive detector such as a video camera, e.g. of the CCD type, carried by the movable object and capable of being swivelled on said object about at least one axis, means for determining the angular position of the detector about said axis, targets disposed in predetermined locations relative to the displacement zone of the movable object, and data processing means connected to the above-specified detector to receive signals corresponding to said targets sighted by the detector and to deduce therefrom the accurate position and orientation of said movable object by triangulation.
Advantageously, the apparatus also comprises motorized means for stepwise rotation of the detector, enabling the detector to be moved into angular positions that are defined with a high degree of repeatability.
The targets wh
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Abitbol Marc
Maillart Jean-Luc
Bertin & Cie
Elmore Reba I.
Rao Sheela S.
Sollac
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