Method And Facility For Automatically Gripping An Object

Abstract

A method of using a polyarticulated system associated with a vision system for automatically picking up an article situated in a zone suitable for receiving at least one article, the polyarticulated system including at least one pick-up member suitable for taking hold of an article via at least one specific zone of the article. In accordance with the invention, the method includes at least the steps of: taking an image of the article-receiving zone; processing the information resulting from the 3D image and identifying all of the specific zones that are present on the articles to be taken hold of, and that are compatible with the pick-up member(s); locating the identified compatible specific zone(s); choosing one of the located compatible specific zones and automatically defining a pick path; and taking hold of the corresponding article along the defined path.

Claims

1. A method of using a polyarticulated system associated with a vision system for automatically picking up an article situated in a zone suitable for receiving at least one article, said polyarticulated system including at least one pick-up member suitable for taking hold of an article via at least one specific zone of said article, said method comprising at least the steps of: taking an image of the article-receiving zone with the vision system; processing the information resulting from the image and identifying all of the specific zones that are present on the articles to be taken hold of, and that are compatible with the at least one pick-up members; locating, in position and in orientation, the identified compatible at least one specific zones; choosing one of the located compatible specific zones and automatically defining a pick path along which the corresponding pick-up member should take hold of the corresponding article via the chosen compatible specific zone; and taking hold of the corresponding article along the defined path.

2. A method of automatically picking up an article according to claim 1, characterized in that the step of choosing one of the located compatible specific zones comprising of weighting each identified zone with a coefficient that is a function of probabilities of the zone being successfully taken hold of by the corresponding pick-up member, and choosing the zone that has the highest probabilities of being successfully taken hold of.

3. A method of automatically taking hold of an article according to claim 1, characterized in that the step of defining a pick path comprises defining a shortest and quickest path.

4. The method of automatically picking up an article according to claim 1, characterized in that the article to be taken hold of is in a loose pile of a plurality of different articles to be taken hold of.

5. The method of automatically picking up an article according to claim 4, characterized in that the method further comprises a step of identifying the articles that are at highest heights, and in that the located specific zone is chosen from among the zones located on the article that is identified as being the highest.

6. The method of automatically picking up an article according to claim 1, characterized in that the method further comprises a step comprising firstly checking whether the article has been taken hold of by the pick-up member, and, secondly, choosing another located compatible specific zone when a determined number of unsuccessful attempts to take hold of the article have been made.

7. The method of automatically picking up an article according to claim 1, characterized in that the step of identifying compatible specific zones of the articles to be taken hold of comprises identifying continuous zones when the pick-up member is of a suction cup type.

8. The method of automatically picking up an article according to claim 1, characterized in that the step of identifying compatible specific zones of the articles to be taken hold of comprises identifying edges or generator lines, when the pick-up member is of a clamp type, and wherein a maximum spacing between said edges or generator lines is less than a maximum possible spacing between the jaws of said clamp.

9. An installation for automatically picking up an article, said installation comprising a polyarticulated system associated with a vision system, and a zone suitable for receiving at least one article to be taken hold of, said polyarticulated system including at least one pick-up member suitable for taking hold of an article via at least one specific zone of said article, said vision system being suitable for taking an image of the article-receiving zone, said installation being characterized in that said vision system and said polyarticulated system are associated with processing and computation means suitable for processing the information resulting from the taken image, for identifying all of the specific zones that are present on the articles to be taken hold of, and that are compatible with the pick-up members, for locating, in position and in orientation, the identified compatible specific zones, and for automatically defining a pick path along which the corresponding pick-up member should take hold of the corresponding article via the chosen compatible specific zone.

10. The installation for automatically picking up an article according to claim 9, characterized in that the pick-up member of the polyarticulated system is in the form of at least one clamp.

11. The installation for automatically picking up an article according to claim 9, characterized in that the pick-up member of the polyarticulated system is in the form of at least one suction cup.

12. The installation for automatically picking up an article according to claim 9, characterized in that the pick-up member(s) is/are provided with elastically deformable members arranged at the portions of said pick-up members that are designed to come into contact with the article to be taken hold of, said elastically deformable members behaving flexibly so as to adapt to the type of the article to be taken hold of.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Other characteristics and advantages of the invention appear clearly from the following description that is given below by way of non-limiting indication, with reference to the accompanying figures, in which:

[0046] FIG. 1 is a diagrammatic perspective view of an installation of the invention for automatically picking up an article;

[0047] FIG. 2 is a diagrammatic perspective view of the pick-up members of the polyarticulated system;

[0048] FIG. 3 is a diagrammatic perspective view of a pick-up member of the clamp type of the polyarticulated system; and

[0049] FIG. 4 is a diagrammatic perspective view of a pick-up member of the suction cup type of the polyarticulated system.

DETAILED DESCRIPTION OF THE INVENTION

[0050] With reference to FIG. 1, an installation (1) of the invention for automatically picking up an article (2) includes a polyarticulated system (3) and an article-receiving zone (4).

[0051] The polyarticulated system (3) is, for example, a six-axis robot that is well known from the state of the art. Said polyarticulated system (3) is suitable for taking hold of an article (2) via a specific zone of said article (2). To this end, said polyarticulated system (3) includes three pick-up members (5), and is associated with a vision system (9).

[0052] The articles (2) to be taken hold of are disposed randomly in loose manner in the article-receiving zone (4). For example, the articles (2) are of different sizes, shapes, and types.

[0053] The article-receiving zone (4) that is shown is constituted by loose pile of articles (2) to be extracted one-by-one.

[0054] With reference to FIG. 2, the pick-up members (5) may be of any suitable type. The essential requirement is for them to be suitable for taking hold of an article (2) via a specific zone of said article (2). In the embodiment shown, the pick-up members (5) are in the form of a clamp (6), of a first suction cup (7a), and of a second suction cup (7b), both suction cups operating by suction.

[0055] With reference to FIG. 3, the clamp (6) comprises two jaws (6a) suitable for moving apart and for coming together to take hold of an article (2). The specific zones of an article (2) that are suitable for being taken hold of by said clamp (6) are edges or generator lines that are preferably parallel. Naturally, the maximum spacing between said edges or generator lines must be less than the maximum possible spacing between the jaws (6a) of said clamp (6). On its portion designed to be in contact with the article (2) to be taken hold of, each of the jaws (6a) advantageously has an elastically deformable member (8) behaving flexibly so as to adapt to the type of said article (2) to be taken hold of.

[0056] With reference to FIG. 4, and in a manner that is well known from the state of the art, a suction cup (7) is associated with suction means. At its end, said suction cup (7) is provided with an elastically deformable member (8) in the form of a sleeve suitable for being applied to a specific zone of an article (2) to take hold of said article (2) by suction. The elastically deformable sleeve (8) is designed to make the contact with the article (2) to be taken hold of. The elastically deformable sleeve (8) has a first level of compliance or flexibility, in particular determined to adapt to a certain type of article (2) that is fragile. This sleeve (8) makes it possible to take hold of fragile articles (2) without breaking them.

[0057] The specific zones of an article (2) that can be taken hold of by a first suction cup (7) are continuous, i.e. they are surfaces that are substantially plane and of dimensions suitable for bearingly receiving said elastically deformable sleeve (8) of the suction cup (7).

[0058] The first and second suction cups (7a, 7b) are similar, except for their elastically deformable sleeves (8) that have different levels of compliance. For example, the second suction cup (7b) is larger than the first suction cup (7a) so as to be adapted to heavier and less fragile articles (2).

[0059] The vision system (9), which is preferably disposed in register with the article-receiving zone (4), is suitable for taking an image of the article-receiving zone (4), and may be of any suitable type, such as, for example, a 3D camera, or else a camera operating in stereo mode.

[0060] In addition, the installation (1) has processing and computation means associated with the polyarticulated system (3) and with the vision system (9).

[0061] Said processing and computation means are of any suitable type, and may, for example, be in the form of a microprocessor.

[0062] Said processing and computation means are suitable for processing the information resulting from the taken image in such a manner as to identify, on the articles (2) to be taken hold of, edges or generator lines that are preferably parallel and that are spaced apart by spacing less than the maximum spacing between the jaws (6a) of the clamp (6). They are also suitable for identifying, on the articles (2) to be taken hold of, plane surfaces whose dimensions are suitable for bearingly receiving the elastically deformable sleeves (8) of the first and section suction cups (7a, 7b).

[0063] Said processing and computation means also make it possible to locate, in position and in orientation, said identified compatible specific zones, and to choose one of the located compatible specific zones.

[0064] Choosing the zone to be taken hold of consists, for example, in weighting each identified zone with a coefficient that is a function of the probabilities of the zone being successfully taken hold of by the corresponding pick-up member (5), and in choosing the zone that has the highest probabilities of being successfully taken hold of. In practice, weighting coefficients are assigned for each identified and compatible zone, as a function of one or more parameters. The parameters used may be of any type such as, for example, the height of the zone to be taken hold of, the area of the visible surface, and the inclination of the zone to be taken hold of. Each zone to be taken hold of therefore has weighting for each of the chosen parameters. Then, an average is taken of each weighting of the zone to obtain a score. Depending on the type of the weighting, the zone having the highest score, or the lowest score is chosen to be taken hold of.

[0065] Once the specific zone has been chosen, which zone is, for example, a plane surface that can be taken hold of by one of the suction cups (7a, 7b), or indeed two parallel edges that can be taken hold of by the clamp (6), said processing and computation means are suitable for automatically defining a pick path along which the corresponding pick-up member should take hold of the corresponding article (2) via said chosen compatible specific zone. The installation (1) of the invention thus makes it possible to implement a method of automatically picking up an unknown article (2).

[0066] In accordance with the invention, the method comprises the steps consisting in: [0067] taking an image of the article-receiving zone (4) by means of the vision system (9); [0068] processing the information resulting from the image and identifying all of the specific zones that are present on the articles (2) to be taken hold of, and that are compatible with the pick-up member(s) (5); [0069] locating, in position and in orientation, the identified compatible specific zone(s); [0070] choosing one of the located compatible specific zones and automatically defining a pick path along which the corresponding pick-up member (5) should take hold of the corresponding article (2) via the chosen compatible specific zone; and [0071] taking hold of the corresponding article (2) along the defined path.

[0072] This method is advantageous in that it makes it possible to take hold of any article (2) whatsoever, whatsoever without learning the article (2) or the pick path along which said article (2) should be taken hold of.

[0073] In accordance with the invention, one of the pick-up members (5) may be preferred over the others. An order of preference for use of the pick-up members (5) may be established.

[0074] If, the clamp (6) is given first preference, during the processing of the image taken by the vision system (9), one of the located specific zones is chosen only from among those that could be taken hold of with said clamp (6).

[0075] The method of the invention is advantageous because it makes it possible to separate to an initial extent loosely-disposed unknown articles (2) automatically and rapidly, without requiring the intervention of an operative, or prior learning of the article (2), or of the pick path along which the article (2) should be taken hold of.

[0076] Naturally, the method and the installation (1) of the invention may implement a plurality of polyarticulated systems (3), each of which may be associated with the same vision system (9), or indeed each of which may be associated with its own vision system (9). Thus, when one of the polyarticulated systems (3) moves an article (2) that has been taken hold of, another polyarticulated system (3) may, while said article (2) that has been taken hold of is being moved, take hold of another, and so on, thereby saving time. This makes it possible to perform pick and place operations for picking and placing unknown articles (2) optimally and quickly. After it has been taken hold of, the article (2) may be handled and processed in any desired manner, e.g. it can be conveyed to a processing station or indeed be placed in a specific article-receiving tray or bin.