Robotic gripper repositioning interface

Abstract

Robotic gripper repositioning interface (1) intended to be interposed between: a robotic arm (2) which has at least one degree of freedom and which further includes at one of its ends a gripper attachment plate (5); and a gripper (3) having a removable attachment adapted to be mounted on the gripper attachment plate of the robotic arm; this repositioning interface comprising: – a proximal base (10) adapted to be fixed on the plate of the robotic arm and extending along an axis (A10) from the plate of the robotic arm; – a distal end (11) adapted to receive the gripper attachment; – a pivoting device (12) adapted to drive the distal end (11) in rotation about at least one pivot axis (A12) which is transverse to the axis (A10) of the proximal base (10);– a centering device (13) adapted to drive the distal termination (11) in translation along at least one axis contained in a plane intersecting the axis (A10) of the proximal base (10). Figure for the abbreviation: Fig.4;

Description

Title of the invention: Robotic gripper repositioning interface technical field

[0001] The invention relates to the field of robotics and more specifically to the field of gripping accessories adapted to be mounted removably at the end of robotic arms.

[0002] The invention falls within the framework of dexterous robotics, that is to say, reproducing at least partially the ability of the human hand to manipulate an object after grasping it, and to orient it in particular directions.

[0003] An emblematic example of dexterous manipulation is that of a human hand screwing a nut or a light bulb. This operation involves complex and coordinated movements of the arm, wrist and fingers, the fingers being capable of both translating the object and rotating it, notably by rolling movements without slipping on the surface of the grasped object. PREVIOUS ART

[0004] Most robotic grippers used in industry are not reorientable; that is, they consist of only a simple grasping element, which is thus located at the end of a robotic arm. Once the object is grasped, it cannot be repositioned relative to the gripper itself, and only the joints of the robotic arm allow the grasped object to move. Combined with vision systems or other sensors, these grippers are widely used in industry and are satisfactory for simple and repetitive tasks. However, they do not allow the reorientation of the grasped objects and are therefore not suitable for complex tasks requiring gripper dexterity.

[0005] There are also grippers with multiple fingers, each finger having two or three joints, or even more, allowing for complex movements through finger coordination. Some of these grippers allow for the repositioning and reorientation of a grasped object within the gripper itself, without involving the joints of the associated robotic arm. These devices include anthropomorphic grippers with five fingers, attempting to reproduce the behavior of the human hand as closely as possible. These grippers can thus manipulate objects between their fingers to rotate, reposition, observe, etc. However, these grippers are complex and are primarily the product of research laboratories. For example, these grippers can implement up to 20 degrees of freedom or more, and up to 42 associated motors. Because of Due to their numerous joints and motors, they are fragile and require costly maintenance. Their high complexity leads to significant costs and reliability that is difficult to control, and they are therefore currently little used in industry. Description of the invention

[0006] The invention aims to improve the dexterous gripping means of the prior art.

[0007] To this end, the invention relates to a robotic gripper repositioning interface intended to be interposed between: a robotic arm having at least one degree of freedom and further comprising at one of its ends a gripper attachment plate; and a gripper comprising a removable attachment adapted to be mounted on the gripper attachment plate of the robotic arm; this repositioning interface comprising: - a proximal base adapted to be fixed on the robotic arm platform and extending along an axis from the robotic arm platform; - a distal termination adapted to receive the attachment of the gripper; - a pivoting device adapted to drive the distal termination in rotation around at least one pivoting axis which is transverse to the axis of the proximal base; - a centering device adapted to drive the distal termination in translation along at least one axis contained in a plane intersecting the axis of the proximal base.

[0008] According to another object, the invention relates to a method for repositioning a robotic gripper on a robotic arm equipped with a repositioning interface as described above, this method comprising the following steps, after grasping an object: - pivoting of the object using the pivoting device; - translation of the object using the centering device; so as to substantially align a predetermined axis of the object with the axis of the proximal base of the repositioning interface.

[0009] These process steps can be performed one before the other, one after the other, or simultaneously.

[0010] According to another object, the invention relates to a method for repositioning a robotic gripper on a robotic arm equipped with a repositioning interface as described above, this method comprising the following steps, after grasping an object: - pivoting of the object using the pivoting device; - translation of the object using the centering device; so as to substantially align a predetermined axis of the object with the axis of an intermediate pivot of the repositioning interface.

[0011] These process steps can be performed one before the other, one after the other, or simultaneously.

[0012] The invention makes it possible to increase the dexterity of robotic grippers, by adding reorientation functions to these grippers and to the conventional robotic arms that are normally associated with them.

[0013] The invention is particularly advantageous for giving a dexterity character to simple and robust grippers, but it can also be implemented to further increase the dexterity of an already advanced gripper, such as an anthropomorphic robotic hand.

[0014] The gripping operations that are described as dexterous have at least the following three functions:

[0015] - the grasping itself, which consists of grasping in the most stable way possible objects of the greatest possible variety, whether in terms of their shape, size or weight. The interface according to the invention allows, for example, the use of conventional grippers from industry, which are simple, reliable and low cost;

[0016] - the manipulation of the seized objects, which consists of moving and / or reorienting the objects grasped within the gripper itself, if possible at high speed and over large amplitudes. This manipulation allows the grasped object to be positioned and oriented in a more favorable configuration for performing the intended operations. The interface according to the invention acts here in coordination with the capabilities of the gripper, whatever its type;

[0017] - the use of the seized objects, whether to collect information on The environment (for example, when the grasped object is a camera), or to act on the environment with the grasped object (for example, to perform insertion or screwing tasks, which are very common needs in industry). In the industrial sector, applications include screwing screws or nuts in hard-to-reach environments, inserting special connectors or clips, etc., or, in agriculture, the complex movements required, for example, to pick fruits or vegetables. The interface according to the invention allows, in particular, for better utilization of the degrees of freedom of the robotic arm and the degrees of freedom provided by the gripper, regardless of its type.

[0018] These three different types of actions are often confused and the repositioning interface according to the invention makes it possible to separate them.

[0019] The addition of the repositioning interface between a robotic arm and a gripper allows for the reorientation of the grasped object. In the case where the robotic arm is equipped with a rotating platform, the rotation of the robotic arm's platform, carrying the interface The repositioning interface and the gripper can be used to advantage. The proximal base of the repositioning interface can be mounted on the robotic arm's platform, which, when this platform is a rotating platform, allows the proximal base to rotate around an axis. Any other rotation around a particular axis of the repositioning interface can also be used. Parts can then be gripped so that an axis of interest of the gripped object is, after repositioning, aligned with its proximal base, and can benefit from the rotation of the robotic arm's platform, not to position the gripper (which is the classic function of a robotic arm platform), but to act on the gripped object, or in alignment with a particular axis of the repositioning interface.The repositioning interface according to the invention thus makes it possible, for example, to transform the last degree of freedom of a robotic arm into a working axis to act on the grasped object, for example for screwing an element or for rotating a camera, this screwing or this camera movement also being able to be carried out in alignment with a particular axis of the repositioning interface.

[0020] For example, nuts gripped obliquely and / or offset from the center of the gripper can be reoriented and / or repositioned so that they can be screwed in simply by rotating an axis, with the option of this axis being located on the gripper, on the repositioning interface, or on the robotic arm. A complex screwing operation, following a random gripping operation, can thus be reduced, after appropriate reorientation and / or repositioning, to a simple rotation of an axis, rather than coordinated and large-amplitude movements of several axes, or even all the axes, of the robotic arm.

[0021] The invention, by focusing on the functions of grasping, manipulating and using grasped objects, by decoupling and simplifying them, goes against the tendency to complicate graspers, by adding a particular mobility to the grasping function regardless of the gripper chosen.

[0022] Simple, robust and inexpensive grippers can thus benefit from functional improvement by adding the repositioning interface according to the invention.

[0023] The invention can be easily integrated without significant modifications into existing means of production, and at a lower cost, by interposing the repositioning interface between an existing robotic arm, already in place, and its gripper.

[0024] The invention increases the versatility of a robotic arm, for example by allowing the use of a grasped object in different directions and at different angles, without modifying (or with very little modification) the configuration of the robotic arm. This also facilitates use in cluttered environments, for example with obstacles to be circumvented.

[0025] Furthermore, unlike conventional dexterous grippers, which have numerous axes and motors concentrated in a very compact manner as close as possible to the grasped object and are designed to enable both grasping, manipulation, and use of the object, the invention allows the various motors involved in these three functions to be distributed. This is achieved by adding, to the gripper and the robot that usually support the motors related to grasping and using the object, an additional element (the repositioning interface) that supports the motors related to manipulating the objects. It is then possible to act on the grasped object using the motors located on the robotic arm, as well as on the gripper itself, in addition to the repositioning interface.

[0026] The invention thus makes it possible to decompose the functions performed by a robot equipped with a gripper by adding degrees of freedom on targeted axes which, thanks to a synergy between these axes and the robotic arm's mounting plate, allow any gripper to have superior dexterity. It is particularly suited to the deployment of dexterous gripping solutions in industry.

[0027] The repositioning interface according to the invention may include the following additional features, alone or in combination:

[0028] - the pivoting device comprises a movable support following a trajectory semi-circular centered on said pivot axis;

[0029] - the moving support has a trajectory comprising at least one position in which it is arranged on the axis of the proximal base;

[0030] - the pivoting device comprises a semi-circular slide on which is mounted a slide forming said mobile support;

[0031] - said slide has a cantilevered portion so that the slide presents a portion arranged opposite the axis of the proximal base;

[0032] - the pivoting device comprises at least two arms articulated by a pivot, one arms carrying the mobile support at its end;

[0033] - at least one of said arms is curved;

[0034] - the pivot axis forms an angle with the axis of the proximal base;

[0035] - the angle formed by the pivot axis and the axis of the proximal base is at minus 30°;

[0036] - the angle formed by the pivot axis and the axis of the proximal base is approximately a right angle;

[0037] - the pivot axis and the axis of the proximal base are concurrent;

[0038] - the centering device is adapted to drive the distal termination in translation along at least one axis;

[0039] - the centering device includes a translation table adapted to drive the distal termination in translation along at least two straight and orthogonal axes contained in said plane secant to the axis of the proximal base;

[0040] - the centering device comprises at least two arms connected by a pivot, adapted to to move the distal termination in translation in said plane secant to the axis of the proximal base;

[0041] - the repositioning interface includes an additional pivot arranged between the proximal base and the rest of the repositioning interface;

[0042] - the repositioning interface includes an extension device in the direction of the axis of the proximal base positioned between the proximal base and the rest of the repositioning interface;

[0043] - the repositioning interface includes a pivoting device additional arranged between the distal termination and the rest of the repositioning interface;

[0044] - said additional pivoting device comprises a semi- circular on which a slider is mounted, the distal end being fixed on this slider;

[0045] - the pivoting device is arranged in a proximal position relative to the centering device, the pivoting device being adapted to pivot the centering device around the pivoting axis;

[0046] - the pivoting device is adapted to occupy: at least one angular position in which the centering device is adapted to drive the distal termination in translation along at least one axis contained in a plane intersecting the axis of the proximal base; and at least one angular position in which the centering device is adapted to drive the distal termination in translation along at least one axis contained in a plane parallel to the axis of the proximal base;

[0047] - the repositioning interface includes an intermediate pivot between the device of pivoting and centering device;

[0048] - the centering device is arranged in a proximal position relative to the pivoting device, the centering device being adapted to drive the pivoting device in translation;

[0049] - the repositioning interface includes an intermediate pivot between the device and centering and pivoting device;

[0050] - the repositioning interface includes an intermediate pivot disposed between the distal termination and the rest of the repositioning interface;

[0051] - the proximal base is adapted to be driven in rotation around its axis by the robotic arm mounting plate. PRESENTATION OF THE FIGURES

[0052] Other features and advantages of the invention will become apparent from the following non-limiting description, with reference to the accompanying drawings in which:

[0053] - [Fig. 1] is a general view of a robotic arm equipped with a gripper and the repositioning interface according to the invention;

[0054] - [Fig.2] illustrates the gripping of an object;

[0055] - [Fig.3] illustrates the repositioning interface without the gripper;

[0056] - [Fig.4] illustrates the repositioning interface after reconfiguration;

[0057] - [Fig.5A] and [Fig.5B] illustrate sequences of screwing a nut;

[0058] - Figures [Fig. 6] and [Fig. 7] illustrate further examples of the interface of repositioning;

[0059] - Figures 8 and 9 illustrate another example of the repositioning interface in two different configurations;

[0060] - Figures [Fig. 10], [Fig. 11], [Fig. 12] and [Fig. 13] illustrate different examples of grippers that can be used with the repositioning interface;

[0061] - Figures [Fig. 14] and [Fig. 15] illustrate further examples of the interface of repositioning;

[0062] - Fig. 16, Fig. 17, and Fig. 18 are examples of configuration of the repositioning interface;

[0063] - Figures 19, 20, 21 and 22 illustrate another example of the repositioning interface in different usage situations.

[0064] Similar and common elements in the various embodiments bear the same reference numbers to the figures. DETAILED DESCRIPTION

[0065] The invention relates to a repositioning interface 1 which is intended to be interposed between the end of a robotic arm 2 and a gripper 3.

[0066] The robotic arm can implement any known kinematic chain enabling the movement of an end 4 equipped with a plate 5, along at least one degree of freedom. The robotic arm is, for example, a multi-jointed arm comprising several rotational degrees of freedom in series (advanced multi-jointed arms generally comprise 6 to 8 rotational degrees of freedom in series and allow the positioning of the plate 5 located at its end 4 in numerous positions and orientations). The robotic arm can also advantageously include, at its base, a parallel robot structure, for example of the "Delta" type, or a Cartesian XYZ structure, on which are located other axes of translation or rotation, and an end equipped with a plate. The robotic arm can also be a parallel robot, for example a robot Delta or a Gough-Stewart platform, or on the contrary be extremely simple, with only one degree of freedom, such as a rotating axis, or a rail.

[0067] In the illustrative example in the figures, the robotic arm 2 is a multi-jointed arm, the end 4 of which includes the plate 5. This plate 5 is mounted on the end 4 of the robotic arm 2 by means of a pivot and a suitable motorization (not visible in the figures).

[0068] Regardless of the arrangement of the robotic arm 2, it therefore has a plate 5 at its end 4, allowing the repositioning interface 1 and the gripper 3 to be mounted on it, which will be adapted for the task for which the assembly is intended. As an optional feature, the plate 5 can be rotatable.

[0069] Fig. 1 is a general view illustrating a robotic arm 2 with six degrees of freedom equipped with a repositioning interface 1 according to the invention, and a gripper 3.

[0070] The gripper 3 is a classic tool in the field of robotics and is intended to grasp objects 7 (these objects 7 can themselves be tools) to perform the desired function for this robotic assembly.

[0071] The gripper 3 can be of any type known in the field of robotics, whether simple or complex. The various figures illustrate several types of grippers that can be used interchangeably with the repositioning interface 1. By way of example, the gripper 3 can be: - a two-finger gripper 8A, 8B simple (parallel jaws), as in the example of figures 1 to 9; - a two-finger gripper 8A, 8B more complex, with several joints, as in the example of [Fig. 10]; - a gripper 8 with two flexible, continuously deforming grasping fingers 8A, 8B of the "soft robotics" type as in the example of [Fig.1 1]; - a gripper 8 with more than two grasping fingers, here three fingers 8A, 8B, 8C each having three joints in the example of [Fig. 12], or any other number of grasping fingers and joints per finger, whether the movements of the fingers and / or joints are coupled or not; - a gripper 3 equipped with a magnetic head 9 adapted to grasp ferromagnetic objects 7, as in the example of [Fig. 13]; - a dexterous gripper, such as an anthropomorphic robotic hand, as in the examples in figures 15 and 17 to 22.

[0072] The gripper 3 could also be equipped with a vacuum pouch (i.e., a flexible pouch capable of deforming to conform to the shape of an object to be grasped and filled with a fine powder consisting, for example, of coffee grounds or apricot kernel powder), this pouch being connected to a device for creating a vacuum in it, so as to compress and make almost rigid the powder filling it. pocket, thus ensuring a firm grip on the object) arranged in place of the magnetic head 9 of [Fig. 13], and it could be equipped with several vacuum pockets attached to the end of all or part of the gripper fingers of the gripper 8, whether the gripper 8 has two fingers, three fingers, or more than three fingers. Such vacuum pockets could also be arranged on all or part of the bodies constituting the gripper fingers and the body of the gripper, and not only at the ends of the gripper fingers.

[0073] Regardless of the gripper 3 implemented, the invention functionally allows this gripper to be upgraded, adding a degree of dexterity by implementing the repositioning interface 1.

[0074] The gripper 3 is thus mounted by conventional fixings on the repositioning interface 1, rather than directly on the robotic arm 2. The repositioning interface 1 is in fact mounted at the end of the robotic arm 2, on the plate 5 of the robotic arm in the examples shown, while the gripper 3 is fixed on the repositioning interface 1, with its removable fixing which, conventionally, is normally adapted to be mounted at the end of the robotic arm, with the necessary means of an adapter piece (not shown).

[0075] The repositioning interface 1 comprises: - a proximal base 10, which is adapted to be fixed to the end of the robotic arm, on the plate 5 of the robotic arm 2 in the examples shown, and which extends along an axis (A 10) from the plate of the robotic arm, this proximal base being adapted to be driven in rotation around the axis A10 by the plate 5 when the latter is rotating; - a distal termination 11, which is adapted to receive the attachment of the gripper 3.

[0076] The gripper 3 is thus mounted by its attachment on the distal termination 11 of the repositioning interface 1.

[0077] As can be seen in Figures 2 to 5B, the repositioning interface 1 also includes: - a pivoting device 12, which is adapted to drive the distal termination 11 in rotation around a pivoting axis A12, which is transverse to the axis A10 of the proximal base 10; - a centering device 13, which is adapted to drive the distal termination 11 in translation along at least one axis contained in a plane which may be secant to the axis A10 of the proximal base 10. The centering device 13 can be made by any subsystem allowing the translation of an element, whether this translation is rectilinear or curvilinear.

[0078] The pivoting device 12 can be implemented by any subsystem allowing rotation of the distal termination 11 around a pivoting axis A12. This axis of The pivot axis A12 is transverse to the axis A10 of the proximal base 10, meaning that these two axes, A12 and A10, are not parallel. The pivot axis A12 therefore forms a non-zero angle with the axis A10, although these two axes are not necessarily concurrent. According to an optional preferred feature, the pivot axis A12 and the axis A10 are concurrent, which simplifies the control of the repositioning interface movements.

[0079] According to a preferred feature, the angle formed by the pivot axis A12 with the axis A10 is preferably greater than 30°, or even substantially 90°, to maximize the pivoting capacity of the distal termination 11, and therefore of the gripper 3 mounted thereon.

[0080] In the illustrated examples, this pivoting device 12 comprises a movable support 17, on which the distal termination 11 is mounted (directly or indirectly), this movable support 17 being movable in a rotation centered on the pivot axis A12. The distal termination 11 is therefore mounted on the movable support 17 either directly or indirectly via the centering device which is further adapted to drive this distal termination 11.

[0081] The pivoting device 12 is for example made by a slide 14, or a rail, of semi-circular shape, that is to say which extends along a circle centered on the pivot axis A12, as in the examples of figures 1 to 13, 15, and 16. In these examples, the movable support 17 is formed by a slide cooperating with the slide 14, and which is therefore movable along a circular trajectory.

[0082] In this example, the slide 14 has an overhanging portion 30 so that the slide 14 has a portion arranged opposite the axis A10 of the proximal base 10, allowing the slide forming the movable support 17 to occupy a position in which it is on the axis A10.

[0083] The pivoting device 12 can also be constituted, for example, by a set of rigid arms and pivots, the movable support 17 then being carried by one of the arms, as in the examples of Figures 14, and 17 to 22. In these examples, the pivoting device 12 comprises two rigid arms 15A, 15B, connected by a pivot 16. The rigid arm 15A is movable in rotation about an axis located between the carriage 19 of the centering device 13 and the arm 15A (as for example in Figures 14, 17, and 18), or about the axis A10 (as for example in Figures 19 to 22), and the gripper 3, fixed on the distal termination 11, is movable in rotation relative to the movable support 17 disposed at the end of the arm 15B. The combined movements of these three joints, motorized and controlled, and whose axes are not parallel in pairs, allow the generation of rotations of the distal termination 11 and the grasper 3.For example, it is possible to generate a movement equivalent to that generated by a semi-circular rail and a slider around the A12 axis.

[0084] Alternatively, the pivoting device 12 can be implemented by any other known mechanical device capable of rotating a part, such as a motorized shaft on bearings, etc.

[0085] The centering device 13 can be implemented by any subsystem enabling the translation of an element, whether this translation is rectilinear or curvilinear. The centering device 13 can, for example, consist of a translation table 18 mounted on the pivoting device 12, as in the example of Figures 1 to 7. Figure 3 illustrates the repositioning interface 1 without the gripper 3, so as to make the structure of the translation table 18 visible. In this example, the translation table 18 is, by way of illustration, a motorized and controlled Cartesian XY table enabling the movement of a carriage 19 along two perpendicular rectilinear translations in a plane.

[0086] The centering device 13 is adapted to drive the distal termination 11 in translation along a plane, thanks to the movement of the carriage 19 on which the distal termination 11 and therefore the gripper 3 is mounted, directly or indirectly. This plane can be a plane which is itself mobile in rotation thanks to the pivoting device 12, when the latter is in a proximal position relative to the centering device 13, as in the examples of figures 1 to 7, 15 and 16.

[0087] The centering device 13 is adapted to drive the distal termination 11 in translation in at least one plane which may be intersecting the axis A10, as is the case, for example, in the configuration of [Fig. 4]. This plane may be fixed relative to the plate 5, or movable thanks to the pivoting device 12. When this plane is movable, it has at least one position in which it is intersecting the axis A10, although it also has other positions in which it may not be intersecting the axis A10 (for example, in the position of [Fig. 2]). The characteristic "a centering device 13 adapted to drive the distal termination 11 in translation along at least one axis contained in a plane which may be secant to the axis A10 of the proximal base 10" is therefore understood here as indicating that the centering device 13, when mobile, has at least one position in which this plane of translation is secant to the axis A10.

[0088] The centering device 13 can also be implemented by a translation device made of arms and pivots, as in the example of [Fig. 15]. In this example, the centering device 13 comprises a first pivot 21 rigidly fixed to the movable support 17 (or to the proximal base 10), a first arm 22 movable in rotation by the pivot 21, a second pivot 23, a second arm 24 movable in rotation by the pivot 23, and an intermediate pivot 20 between the second arm 24 and the distal termination 11. In an advantageous configuration, the first pivot 21, the second pivot 23, and the intermediate pivot 20 between the second arm 24 and the distal termination 11, all The motorized and controlled pivots have parallel axes. Thus, the combined movement of the pivots 21, 23, and the intermediate pivot 20 between the second arm 24 and the distal end 11 allows the distal end 11 to be translated in a plane. This plane intersects the axis A10 in at least one position of the pivoting device 12. Furthermore, the intermediate pivot 20 allows for additional rotation of the distal end 11, and therefore of the gripper 3.

[0089] Note that when the turntable 5 is not rotating, the axis A10 is also present, as the last axis of the robotic arm, but is simply no longer an axis of rotation.

[0090] Preferably, the centering device 13 is adapted to move the distal termination 11 in translation along at least one secant direction, and preferably substantially perpendicular, to the axis A10 of the proximal base 10.

[0091] In addition to the pivoting devices 12 and the centering devices 13, the repositioning interface 1 may also include other additional pivoting and / or centering devices, so as to provide additional dexterity to the gripper 3.

[0092] As can be seen in particular in figures 8 to 14 and 17 to 22, an intermediate pivot 20 can for example also be provided between the centering device 13 and the pivoting device 12, and / or an intermediate pivot 20B can be provided between the pivoting device 12 and the centering device 13, so as to allow a relative rotation of one of these elements with respect to the other.

[0093] The repositioning interface 1 may also include an additional pivoting device 25, as in the example of Figures 19 to 22. In this case, the additional pivoting device 25 is mounted on the pivoting device 12 or on the centering device 13, while the distal end 11 (and therefore the gripper 3) is mounted on this additional pivoting device 25. In the example illustrated in Figures 19 to 22, the centering device 13 is mounted on the pivoting device 12 and the additional pivoting device 25 is mounted on the centering device 13. In the illustrated example, the centering device 13 is mounted on the movable support 17 of the pivoting device 12, via an intermediate pivot 20B. This intermediate pivot 20B allows additional rotation of the centering device 13, the additional pivoting device 25, the distal termination 11, and therefore of the gripper 3.

[0094] The additional pivoting device 25 allows for further rotation of the distal end 11, and therefore of the gripper 3, at the end of the chain. The additional pivoting device 25 can be implemented by any means that allows an element to be rotated about an axis. In the illustrated examples, the additional pivoting device 25 is implemented in the same way as the pivoting device 12 illustrated, for example, in Figures 1 to 13, with a slide with a circular trajectory and a sliding piece moving on this slide, but it could just as well be achieved by a set of rigid arms and pivots.

[0095] The repositioning interface 1 may also include an additional intermediate pivot 20B disposed between the additional pivoting device 25 and the distal termination 11. This additional intermediate pivot 20B allows additional rotation of the distal termination 11, and therefore of the gripper 3.

[0096] As further illustrated in Figures 8 and 9, this additional intermediate pivot 20B can also be arranged between the pivoting device 12 and the distal termination 11 which carries the gripper 3, to allow here again an additional rotation of the distal termination 11, and therefore of the gripper 3, even when the repositioning interface 1 does not have an additional pivoting device 25 as is the case in Figures 19 to 22.

[0097] The repositioning interface 1 may also include an additional pivot 26 disposed between the proximal base 10 and the rest of the repositioning interface 1, as in the example in [Fig. 6]. This additional pivot 26 allows an element adapted to drive the repositioning interface 1 in rotation around an axis equivalent to the axis A10, independently of the platform 5 of the robotic arm 2. The rotation of the additional pivot 26 can complement the rotation of the platform 5 of the robotic arm 2, particularly when the latter is of limited amplitude, or even replace it, particularly when the robotic arm 2 has a platform 5 that is not rotating.

[0098] The repositioning interface 1 may also include an extension device 27 disposed downstream of the proximal base 10. If the repositioning interface 1 includes an additional pivot 26, as in the example of [Fig.7], the additional pivot 26 may be disposed between the proximal base 10 and the extension device 27, and the extension device 27 is then disposed between the additional pivot 26 and the rest of the repositioning interface 1.

[0099] The extension device 27 can also be disposed directly between the proximal base 10 and the rest of the repositioning interface 1 if the latter does not include an additional pivot 26.

[0100] This extension device 27 allows the rest of the repositioning interface 1 to be moved in translation along the axis A10, for example, to accompany the advance of the object when the gripper 3 is used to perform a screwing action, without it being necessary to mobilize the axes of the robot 2, or in addition to the movements of the axes of the robot 2. The extension device 27 can be implemented by any means of translation, and in the illustrated example, it is implemented by a telescopic arm. Of course, the extension device 27 could also be positioned upstream of the additional pivot 26 and not downstream of this additional pivot 26 as illustrated in [Fig.7].

[0101] The gripper can be arranged either with the pivoting device 12 in the proximal position and the centering device 13 in the distal position, or with the centering device 13 in the proximal position and the pivoting device 12 in the distal position.

[0102] When the pivoting device 12 is in a proximal position (i.e. closer to the robotic arm) and the centering device 13 is in a distal position (i.e. further away from the robotic arm, in the direction of the gripper 3), the pivoting device 12 is then mounted on the proximal base 10 (optionally by means of additional elements such as, for example, an additional pivot 26 and / or an extension device 27), while the centering device 13 is then mounted on the pivoting device 12 (optionally by means of additional elements such as, for example, an additional intermediate pivot 20B, illustrated in Figures 19 to 22).The distal termination 11 is then mounted on the centering device 13 (possibly via additional elements such as, for example, an additional intermediate pivot 20 and / or an additional pivoting device 25 and / or an additional intermediate pivot 20B).

[0103] When the centering device 13 is in a proximal position (i.e. closer to the robotic arm) and the pivoting device 12 (or 25) is in a distal position (i.e. further away from the robotic arm, in the direction of the gripper 3), the centering device 13 is then mounted on the proximal base 10 (possibly by means of additional elements such as, for example, an additional pivot 26 and / or an extension device 27, or a pivoting device 12 and / or an intermediate pivot 20B), while the pivoting device 12 (or 25) is then mounted on the centering device 13 (possibly by means of additional elements such as, for example, an additional intermediate pivot 20, as illustrated by example in Figures 8 to 14).The distal termination 11 is then mounted on the pivoting device 12 (or 25, possibly via additional elements such as, for example, an additional intermediate pivot 20B).

[0104] Thus, one or more intermediate pivots 20 can be disposed between a centering device 13 and a pivoting device 12 or the distal termination 11, and one or more intermediate pivots 20B can be disposed between a pivoting device 12 (or 25) and a centering device 13 or the distal termination 11, so that the device in the distal position or the distal termination can be further mobile according to one or more additional rotations around these intermediate pivots 20, 20B.

[0105] All axes (translation and rotation) can be motorized, equipped with measuring devices, and controlled, in a conventional robotic manner, by means of appropriate control electronics. Such devices are implicitly integrated into the robot 2, the repositioning interface 1, and the gripper 3, although they are not shown in the figures.

[0106] The actuation means can be of any type commonly used in robotics, for example DC motors (with or without an iron rotor), self-piloted synchronous motors (so-called "brushless"), pneumatic, hydraulic, thermal actuators, or those using shape memory alloys, piezoelectric materials, or electro-active polymers, or any combination of these principles.These actuators, which can be used with any common type of gearbox (e.g., gear, friction, belt, cable, ball screw, worm, or Harmonie Drive type, or any combination thereof if they have multiple stages), can be positioned at the joints they drive, on the body immediately upstream or downstream of these joints, or they can be located further upstream or downstream of the robot, repositioning interface, or gripper, using suitable transmission means (e.g., belts, cables, connecting rods, or other). These actuators can also be used in pairs at some or all joints (agonist and antagonist actuation), and they can be combined with elastic elements (linear or non-linear springs), arranged in series or parallel to the actuators, for measurement purposes (e.g.configuration of the "series elastic actuators" type), contributing to the forces of the actuators, or opposing them (e.g., return to neutral or reference position). Some joints may also be equipped with brakes, for example friction or powder brakes, or based on the use of rheological fluids.

[0107] The measuring elements can be, for example, joint position sensors (such as optical or magneto-optical encoders, Hall effect sensors, potentiometers, etc.), stroke and end-of-stroke sensors, or force sensors (joint or arranged between the plate 5 and the repositioning interface 1 or between the repositioning interface 1 and the gripper 3), or one or more vision sensors (2D or 3D, in the visible or non-visible spectrum, multispectral or non-multispectral, integrated into the robot 2, the repositioning interface 1, the gripper 3, or any other element of the robot or the environment), classically used in robotics for the control of the various moving elements of the robotic arm 2, the repositioning interface 1, and the gripper 3.For example, they may include a camera (2D or 3D, or a lidar) 29 connected to a three-dimensional vision and positioning system, common in the field of robotics.

[0108] The control electronics and, more generally, the control means for the actuators of the various joints serve to command, control, or regulate their positions and / or the forces generated along or around their axes, or directly in Cartesian space. This can be achieved using control modes based on position, force, impedance, or admittance, for example. This electronics and these control means can be integrated into control units specific to the repositioning interface, or they can be integrated into the controller of the robot or gripper. They can be used to control the axes independently of each other, or to control some or all of the axes in a coordinated manner, or to control the movements of the gripper and / or the object directly in Cartesian space.

[0109] The repositioning interface according to the invention can be used as indicated below, in conjunction with the robotic arm 2 and the gripper 3, in a robotic assembly as illustrated in [Fig. 1].

[0110] In the example shown in Figures 1 to 14, the robotic assembly acts on an object 7, which is a nut. The nut is a particularly interesting illustrative example of an object requiring dexterity to be screwed on under difficult conditions. However, the invention also applies, with the dexterity provided, to any other object that one wishes to grasp and manipulate.

[0111] The robotic arm 2 will first grasp the object 7, even when it is arranged in a loose pile, with random positions, as is the case in a pile of nuts as illustrated in [Fig. 2]. The invention notably eliminates the need for vibratory bowl feeders, parts dispensers, alignment conveyors, or any other complex and costly equipment to organize the objects 7 for grasping.

[0112] In the example illustrated in [Fig.2], the nut is gripped in a random position by the gripper 3, with its axis of rotation in an unchosen orientation, and a position offset from the extension axis of the gripper taking into account the constraints of access to the gripped nut.

[0113] The repositioning interface 1 will then be controlled so as to align an axis of interest of the captured object 7 with another axis of interest of the system, using the positioning and control elements, in particular the camera 29 in this example.

[0114] The repositioning interface 1, thanks to its pivoting device 12 and its centering device 13, makes it possible to align an axis of interest of the object 7 with an axis of the system, whether this axis is located on the gripper, on the repositioning interface, or on the robotic arm. In the illustrated example, the use of the object 7 (a nut) consists of screwing this nut on, and its axis of interest is the axis of rotation of this nut, that is, the axis A7 around and along which this nut must be driven to be screwed on. Furthermore, in the illustrated example where the plate 5 is rotating, the chosen axis of the system is the axis A10 of the proximal base 10, which is the axis of rotation of the plate 5 and which is therefore controlled by the robotic arm 2. Once the axis of interest of the nut 7 is aligned with the axis A10 thanks to the repositioning interface 1, the nut 7 can be screwed by a command from the plate 5 of the robot 2, with advantages such as for example a possibility of continuous screwing, a significant power, etc.

[0115] The repositioning interface 1 can also be configured to facilitate the grasping of the object 7, particularly in cluttered environments, through an appropriate configuration of the pivoting device 12 and the centering device 13. For example, in [Fig.2], the pivoting device 12 positions the gripper 3 in a vertical grasping position.

[0116] Optionally, the repositioning interface 1 may also include a pivot 20B before the distal termination 11, or a pivot 20 located along the kinematic chain of the repositioning interface 1, or a pivot 26 located between the plate 5 and the repositioning interface 1, so as to be able to drive the gripper 3 in rotation on itself.

[0117] The system will thus be controlled to move the robotic arm 2 and to reconfigure the repositioning interface 1 so as to angularly align the axis of interest A7 of the grasped object 7 so that it is substantially parallel, and preferably coincident, with the axis A10 of the proximal base 10, itself aligned with the axis of the plate 5. For this purpose, the pivoting device 12 drives the mobile support 17 in a circular trajectory allowing to angularly reorient the distal end 11 and therefore the gripper 3, and therefore ultimately the object 7, until the axis of interest A7 is substantially parallel to the axis A10.The centering device 13 is activated so as to move the carriage 19 along the two directions of the plane in which the translation table 18 extends, to cause a displacement of the axis of interest A7 of the object 7 captured, until the axis of interest A7 of the object 7 captured is aligned with the axis A10, as in the example of figures 4, 9 to 12 and 14. .

[0118] In this angular position, the grasped object 7 can be brought into contact with the screw onto which it is to be screwed, in order to proceed with the screwing. The reconfiguration of the repositioning interface 1 can be performed after the grasping of the object 7 and while the robotic arm 2 moves towards the screwing area so that the operation is carried out in the background. Similarly, the movements of the pivoting device 12 can be simultaneous with the movements of the centering device 13.

[0119] From the position shown in Figures 4, 9 to 12 or 14, the nut can be screwed on by rotating the proximal base 10 with the robotic arm 2. Figures 5A and 5B illustrate sequences of this screwing: thanks to the repositioning allowed by the repositioning interface 1, the nut is rotated around its axis A7 (which is here confused with axis A10) thanks to a rotation of the plate 5 around axis A10.

[0120] A significant increase in dexterity is thus conferred on the gripper 3, which is here required to screw on a nut grasped loose, in a random position, although the gripper 3 is a very simple clamp, without any internal function for reorienting the grasped object.

[0121] If the robotic arm 2 is equipped with a continuously rotating plate 5, the nut can be screwed or unscrewed continuously.

[0122] The repositioning interface 1 also allows screwing or unscrewing, for example, of a nut with a random grip of the gripper 3 on the nut, as is the case in a hard-to-reach environment.

[0123] If the repositioning interface 1 has an additional axis of rotation, thanks to the additional pivot 26 described, the rotation of the platform 5 of the robotic arm 2 can be replaced or supplemented (for example, to screw or unscrew faster) by this additional pivot 26, as in [Fig. 6]. In this case, the repositioning interface can be used even if the platform 5 is not rotating or its rotation is very limited, for example, if the robot is a parallel robot of the Delta or Gough-Stewart type, on whose moving platform the repositioning interface is fixed by means of the platform 5.

[0124] If the repositioning interface 1 includes an extension device 27 described, the nut can be accompanied in translation along the axis A10, as progress is made due to screwing, by means of this extension device 27, as illustrated in [Fig.7], rather than by the robotic arm 2.

[0125] Fig. 15 illustrates the possibility of such screwing (in this example with another object 7 which is a light bulb) with an anthropomorphic robotic hand type gripper, thus providing an increase in dexterity even for an already evolved gripper 3.

[0126] Figure 16 illustrates the increased dexterity provided by the repositioning interface 1, with an example of an asymmetrical object 7, such as an asymmetrical screw whose head and body are not coaxial. These screws are used in certain industrial sectors for relatively rare, specific needs and, in this example, represent a situation requiring complex means to automate production. The repositioning interface 1, thanks to the centering device 13, allows for considerable flexibility in choosing the axes to be aligned, and the repositioning device 1, in this example, allows the threaded portion of the object 7 (and not the head of the screw) to be centered on the axis A10.

[0127] Figure 17 illustrates another example in which the repositioning interface 1 allows the axis A10 to be aligned with the axis of interest A7 of an object 7 which is a screwdriver, with a gripper 3 which is an anthropomorphic robotic hand. In this example, the grasping of the screwdriver by the gripper 3 can result in multiple possible orientations of the screwdriver, leading to a relatively random gripping situation, before the reconfiguration of the repositioning interface 1 which allows the alignment of the axes and the use of the screwdriver.

[0128] The repositioning interface 1 also enhances the dexterity of advanced grippers 3, such as anthropomorphic robotic hands, by enabling complex movements such as those combining rotations and translations in a specific and coordinated manner, as in the example in [Fig. 18] relating to the placement of an object 7, which is a bayonet-type light bulb. In this example, the repositioning interface 1 assists, or even replaces, the movements of the robotic arm 2 by allowing a translation of the grasped object 7 along axis A10 (using an extension device 27 not visible in the figure) as well as a rotation around this same axis A10.

[0129] When the repositioning interface 1 includes an additional pivoting device 25 described above, an additional degree of dexterity is also achieved, as illustrated in the example of Figures 19 to 22. In this example, it is possible, for instance, to screw an object 7 (a screw-in light bulb) in many directions in space, which the robotic arm 2 could not achieve alone, or only by means of large movements of this robot that could cause collisions with its environment. In [Fig. 19], the additional pivoting device 25 is used to align the screwing axis A7 of the object 7 with the axis A20 of an intermediate pivot 20B. The object 7 can thus be screwed in by rotating the intermediate pivot 20B, and this screwing can take place in a large number of directions in space with difficult angular positions because they are located on different axes of rotation.Figures 20 and 21 illustrate the screwing of object 7 along two other axes perpendicular to that of [Fig. 19]. Note that in the configuration illustrated by [Fig. 21], axis A10 of the proximal base 10 can be used for screwing as well as axis A20. The repositioning interface 1 allows screwing along any intermediate direction between these three axes, which is useful in this example for a robot required to change light bulbs in all directions of space, and in hard-to-reach places, with a robotic arm 2 whose complexity remains manageable.

[0130] Figure 22 illustrates the use of the additional pivoting device 25 for orienting an object under conditions requiring, for example, two working axes. One working axis (A10 in this example) is used to impart a rotation to the object 7 that is not its working rotation (direction A7 in this example with object 7 being a screwdriver), for example, to insert object 7 into an area of specific work. Then another working axis (A20 in this example) is aligned with axis A7 to then proceed with screwing.

[0131] Various embodiments may be implemented. In particular, any known variant in the field of robotics may be implemented for the described translation and rotation axes, as well as the motorizations of these axes, their transmission means (linear or rotary motors, belt drives, motorized pivots, rack and pinion or toothed belt drives, etc.), and their control means.

[0132] The illustrations are also simplified, particularly in their dimensioning, it being understood that the repositioning interface 1 can be reinforced and dimensioned by all conventional means in mechanics, according to the forces and torques for which it is intended in the context of an application.

[0133] Furthermore, the interface 5 can be rotating, and the axis A10 is then an axis of rotation. Alternatively, the interface 5 is not rotating, and the axis A10 is then simply a longitudinal axis of the proximal base fixed to the interface 5 located at the end of the robotic arm.

Claims

Demands

1. Robotic gripper repositioning interface (1) for interposed between: a robotic arm (2) having at least one degree of freedom and further comprising at one of its ends a gripper attachment plate (5); and a gripper (3) comprising a removable attachment adapted to be mounted on the gripper attachment plate of the robotic arm; this repositioning interface comprising: - a proximal base (10) adapted to be fixed on the robotic arm plate and extending along an axis (A10) from the robotic arm plate; - a distal end (11) adapted to receive the gripper attachment; - a pivoting device (12) adapted to drive the distal end (11) in rotation about at least one pivot axis (A12) which is transverse to the axis (A10) of the proximal base (10);- a centering device (13) adapted to drive the distal termination (11) in translation along at least one axis contained in a plane intersecting the axis (A10) of the proximal base (10).;

2. Repositioning interface according to claim 1, characterized in that the pivoting device (12) comprises a movable support (17) following a semi-circular trajectory centered on said pivoting axis (A 12).

3. Repositioning interface according to claim 2, characterized in that the movable support (17) has a trajectory comprising at least one position in which it is disposed on the axis (A10) of the proximal base (10).

4. Repositioning interface according to any one of claims 2 or 3, characterized in that the pivoting device (12) comprises a semi-circular slide (14) on which is mounted a slide forming said movable support (17).

5. Repositioning interface according to claim 4 when it depends on claim 3, characterized in that said slide (14) has a cantilevered portion (30) such that the slide (14) has a portion disposed opposite the axis (A10) of the proximal base (10).

6. Repositioning interface according to any one of claims 2 or 3, characterized in that the pivoting device (12) comprises at least two arms (15A, 15B) articulated by a pivot (16), one of the arms (15B) carrying the movable support (17) at its end.

7. Repositioning interface according to claim 6, characterized in that at least one of said arms (15A,15B) is curved.

8. Repositioning interface according to any one of the preceding claims, characterized in that the pivot axis (A12) forms an angle with the axis (A10) of the proximal base (10).

9. Repositioning interface according to claim 8, characterized in that the angle formed by the pivot axis (A12) and the axis (A10) of the proximal base (10) is at least 30°.

10. Repositioning interface according to claim 9, characterized in that the angle formed by the pivot axis (A12) and the axis (A10) of the proximal base (A10) is substantially a right angle.

11. Repositioning interface according to any one of the preceding claims, characterized in that the pivot axis (A12) and the axis (A10) of the proximal base (10) are concurrent.

12. Repositioning interface according to any one of the preceding claims, characterized in that the centering device (13) is adapted to drive the distal termination (11) in translation along at least one axis.

13. Repositioning interface according to claim 12, characterized in that the centering device (13) comprises a translation table (18) adapted to drive the distal termination (11) in translation along at least two straight and orthogonal axes contained in said plane secant to the axis (A10) of the proximal base (10).

14. Repositioning interface according to claim 12, characterized in that the centering device (13) comprises at least two arms (22, 24) connected by a pivot (23), adapted to drive the distal termination (11) in translation in said plane secant to the axis of the proximal base (10).

15. Repositioning interface according to any one of the preceding claims, characterized in that it comprises an additional pivot (26) disposed between the proximal base (10) and the rest of the repositioning interface (1).

16. Repositioning interface according to any one of the preceding claims, characterized in that it comprises an extension device (27) in the direction of the axis (A10) of the proximal base (10) disposed between the proximal base and the rest of the repositioning interface (1).

17. Repositioning interface according to any one of the preceding claims, characterized in that it comprises an additional pivoting device (25) disposed between the distal termination (11) and the rest of the repositioning interface (1).

18. Repositioning interface according to claim 17, characterized in that said additional pivoting device (25) comprises a semi-circular slide on which a slider is mounted, the distal termination (11) being fixed on this slider.

19. Repositioning interface according to any one of the preceding claims, characterized in that the pivoting device (12) is disposed in a proximal position relative to the centering device (13), the pivoting device (12) being adapted to pivot the centering device (13) around the pivoting axis (A12).

20. Repositioning interface according to claim 19, characterized in that the pivoting device (12) is adapted to occupy: - at least one angular position in which the centering device (13) is adapted to drive the distal termination (11) in translation along at least one axis contained in a plane intersecting the axis (A10) of the proximal base (A10); and - at least one angular position in which the centering device (13) is adapted to drive the distal termination (11) in translation along at least one axis contained in a plane parallel to the axis (A10) of the proximal base (10).

21. Repositioning interface according to one of claims 19 or 20, characterized in that it comprises an intermediate pivot (20B) between the pivoting device (12) and the centering device (13).

22. Repositioning interface according to any one of claims 1 to 18, characterized in that the centering device (13) is disposed in a proximal position relative to the pivoting device (12), the centering device (13) being adapted to drive the pivoting device (12) in translation.

23. Repositioning interface according to claim 22, characterized in that it comprises an intermediate pivot (20) between the centering device (13) and the pivoting device (12).

24. Repositioning interface according to any one of the preceding claims, characterized in that it comprises an intercalated pivot (20, 20B) disposed between the distal termination (11) and the rest of the repositioning interface (1).

25. Repositioning interface according to any one of the preceding claims, characterized in that the proximal base (10) is adapted to be driven in rotation about its axis (A 10) by the robotic arm plate.

26. Method for repositioning a robotic gripper (3) on a robotic arm (2) equipped with a repositioning interface (1) according to any one of claims 1 to 25, characterized in that it comprises the following steps, after grasping an object (7): - pivoting of the object (7) by means of the pivoting device; - translation of the object (7) by means of the centering device; so as to substantially align a predetermined axis of the object (7) with the axis (A10) of the proximal base (10) of the repositioning interface (1).

27. ​​Method for repositioning a robotic gripper (3) on a robotic arm (2) equipped with a repositioning interface (1) according to any one of claims 1 to 25, characterized in that it comprises the following steps, after grasping an object (7): - pivoting of the object (7) by means of the pivoting device; - translation of the object (7) by means of the centering device; so as to substantially align a predetermined axis of the object (7) with the axis (A20) of an intermediate pivot (20B) of the repositioning interface (1).

Images