Optics: measuring and testing – Angle measuring or angular axial alignment
Patent
1987-03-06
1989-01-17
Rosenberger, Richard A.
Optics: measuring and testing
Angle measuring or angular axial alignment
356152, 356372, 356400, 73800, G01D 1116, G01D 1127, G01D 500
Patent
active
047984619
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a system for monitoring the geometry of a mechanical structure comprising interconnected rigid elements, the invention being applicable both to fixed structures whose deformations need to be observed and to structures including moving elements capable of servocontrolled displacements, such as robots or manipulator arms.
Such robots are presently being used more and more in factories for fabrication or assembly purposes in order to perform repetitive tasks which may be relatively complex. They generally comprise a plurality of elements mounted one after the other and capable of being displaced relative to one another in rotation or in translation so that a load or a tool carried by the last element of the robot can be displaced from one predetermined point to another, with the various elements of the robot being provided for this purpose with motors and displacement sensors connected to a data processing system in which the movements to be performed have been programmed.
In order to maintain accuracy, the load which a robot can carry is generally a small fraction of its own weight, typically about 1/20-th, since otherwise the various elements of the robot are subjected, as they move, to bending and twisting deformations which vary as a function of the nature and the size of the load carried by the last element, and also as a function of the positions of the various elements relative to one another.
PRIOR ART
It is already known that such robots can be subjected to repetitive tests in the laboratory or during commissioning in order to determine the difference between the rear position of the load carried by the last element when the robot is in a given configuration, and the theoretical position of the load (i.e. the position which would be occupied if the elements were not deformed), and to attempt to eliminate said difference by modifying the positions actually occupied by the various elements of the robot.
However, such tests and adjustments must be performed all over again whenever the nature, the size, or the displacement of the load are modified.
At present, there exists no system capable of detecting and measuring on a permanent basis the deformation of the elements of a robot regardless of the motion of the robot and the size and nature of the load, and capable of taking account of such deformations in order to correct the position of the load and to eliminate its offset relative to a theoretical position.
DESCRIPTION OF THE INVENTION
The invention seeks to fill this gap and provides a system enabling the above-indicated aim to be achieved.
The invention also provides a system of this type capable of detecting and measuring on a permanent basis the deformations of the elements of a fixed structure, in particular when the location of said structure makes access thereto difficult or dangerous, or else when conventional surveillance means in common use cannot be implemented.
To this end, the invention provides a system for monitoring the geometry of a mechanical structure comprising a plurality of interconnected rigid elements, characterized in that the system comprises means for detecting and measuring on a permanent basis the deformations of said elements by means of an "optical skeleton" formed by segments associated with the elements of the structure, with each segment being constituted by a light beam running along the corresponding element at least between its junctions with the adjacent elements, together with photodetector means associated with each element and towards which at least a fraction of the corresponding light beam is directed.
Each light beam is preferably adjusted to run along the axis of the corresponding element of the structure when said element is not subjected to any external load or stress, and to encounter photo-detector means which are associated in fixed manner to said element. Any subsequent deformation of the element causes the point of impact of the light beam on the photodetector means to move, thereby enabling said displa
REFERENCES:
patent: 3267794 (1966-08-01), Howe
patent: 3684383 (1972-08-01), Johansson
patent: 4471447 (1984-09-01), Williams et al.
Pavlin Cyrille F.
Prevost Marc
Bertin & Cie.
Rosenberger Richard A.
LandOfFree
System for monitoring the geometry of a mechanical structure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System for monitoring the geometry of a mechanical structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for monitoring the geometry of a mechanical structure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2411739