Robotic gripper intended to co-operate with a predefined gripping means device

Abstract

The present invention relates to a robotic gripper (1) configured to grip a predefined gripping means device (2), the robotic gripper comprising a motor (3), an actuating means (4), a force distributor (5), and a finger mechanism (6) comprising two articulated portions (61, 62) and being movable between an open position and a closed position to close the robotic gripper (1) with a view to gripping the gripping means device (2), wherein the motor (3) is configured to drive the actuating means (4) in order to actuate the force distributor (5), and wherein the force distributor is configured to move the finger mechanism (6) from the open position to the closed position, and vice versa, by driving the first portion (61), which drives the second portion (62), so that the finger mechanism (6) grips or, conversely, releases the predefined gripping means device (2).

Description

Robotic gripper intended to cooperate with a predefined gripping means device

[0001] The present invention relates to the field of robots, in particular humanoid robots. More specifically, the invention relates to a robotic gripper intended to cooperate with a predefined universal gripping means device. STATE OF THE ART

[0002] A robotic hand for a humanoid robot is known from the prior art. In particular, such a robotic hand comprises a motor, a screw, a shaft and four fingers each associated with a drive wheel. The motor is connected to one end of the screw, itself connected by its other end to the shaft. The drive wheels are distributed on the shaft and are configured to wind and / or unwind around them a wire extended in the finger with which each is associated.

[0003] Thus, the motor is configured to rotate the screw which is itself configured to rotate the shaft which causes the rotation of the drive wheels and therefore the winding or unwinding of the wires around each drive wheel thus causing the fingers to bend or open. The use of wires in the robotic hand makes it possible to obtain fingers of reduced size, adapting to a plurality of shapes and objects.

[0004] However, over time and through being wound and unwound, the wires become deformed and loosened, causing a lack of precision in the bending and unbending of the fingers, including reduced resistance when gripping. Indeed, the attachment of the wire to the drive wheel results in significant play and therefore a limitation in the accuracy of gripping and in adapting to the plurality of objects. Furthermore, the friction of the wires during use leads to wear of the drive wheels, and therefore the need for regular and costly maintenance. In addition, this deformation of the wires can cause them to slip off the drive wheels, which causes the robotic hand to become completely blocked.

[0005] Furthermore, the diameter of the robotic hand's wires determines the maximum force of the fingers and therefore the grip. Indeed, the thinner the wires, the weaker the gripping force. Thus, the greater the gripping force must be, the larger the wire diameter must be, and therefore the larger the hand's dimensions will be; the training wheels, for example, must be larger.

[0006] The present invention therefore aims to solve at least in part the aforementioned problems by proposing a robotic gripper configured to grip a predefined gripping means device, capable of gripping large loads while keeping a reduced size. PRESENTATION OF THE INVENTION

[0007] More specifically, the invention relates to a robotic gripper configured to grip a predefined gripping means device. The robotic gripper according to the invention comprises a motor, an actuating means, connected to said motor, a force distributor connected to said actuating means, and at least one finger mechanism connected to the force distributor. The finger mechanism comprises at least two portions articulated by means of a connection and said finger mechanism is movable between an open position in which the first portion and the second portion are substantially aligned with each other and a closed position in which the second portion has pivoted with respect to the first portion, in particular to close the robotic gripper in order to grip said predefined gripping means device.The motor is configured to drive said one actuating means so as to actuate the force distributor which is configured to move the finger mechanism from the open position to the closed position, and vice versa, by driving said first portion of the finger mechanism which drives said second portion of the finger mechanism around said link, so that said finger mechanism grips or, conversely, releases, the predefined gripping means device.

[0008] The activated motor drives the rotation of the actuating means which will cause the movement of the force distributor. The movement, by translation of the force distributor, allows the finger mechanism to which it is connected to move from the open position to the closed position, and vice versa. In particular, the force distributor drives the movement of the first portion, which itself drives, by its movement, the movement of the second portion, causing the robotic gripper to close and therefore the finger mechanism to move from the open position to the closed position. The reverse movement is performed for the move from the closed position to the open position.

[0009] Further, the pivot-type connection connecting the first portion and the second portion comprises a disc configured to pivot about an axis of rotation, the first portion and the second portion each being connected to said disc.

[0010] In addition, the force distributor comprises an arcuate rod, the plurality of finger mechanisms being connected by means of a pivot-type connection to said arcuate rod and distributed along its length.

[0011] The force distributor rod is arched so that each finger mechanism has a different angle when connected to it. This allows for kinematics close to that of a human hand when gripping an object. Thus, the finger mechanisms, during their movements, are not parallel to each other but concentrate towards a central point during closing. This allows for a movement similar to that of a human hand and allows for a more compact design of the robotic hand.

[0012] Advantageously, the first portion comprises at least one rod connected on the one hand by means of a pivot-type connection to the force distributor, the second portion comprising at least one other rod, the rod of the first portion and the rod of the second portion being on the other hand connected by the connection connecting the first portion and the second portion.

[0013] The rod of the first portion and the rod of the second portion allow identical movement and gripping from one grip to another. In other words, the rods are rigid elements which do not deform over time despite repeated use, or at least to a lesser extent and more slowly than wires. Gripping is therefore ensured without deterioration by the use of the robotic gripper according to the invention.

[0014]

[0015] The disc allows the second portion to have an angle of inclination relative to the first portion and therefore to adapt perfectly to the gripping device.

[0016] In particular, the first portion and the second portion are each connected to said disc at a fixing point. The fixing point of the first portion to the disc and the fixing point of the second portion to the disc depend on the lengths of the first and second portions as well as the dimensions of the object to be grasped, such as the diameter of the predefined gripping means device. Thus, the accuracy of grasping the predefined gripping means device by the robotic gripper is improved.

[0017] Advantageously, the actuating means comprises at least one gear and one worm screw, the gear being connected to the motor and to the worm screw and the worm screw being connected to the force distributor, the motor being configured to drive said gear in rotation, itself configured to drive said worm screw in translation, configured to drive the force distributor in translation configured to move the finger mechanism from its open position to its closed position and / or from its closed position to its open position.

[0018] Advantageously, the finger mechanism comprises at least one lateral bearing configured to allow alignment of the predefined gripping means in the robotic gripper.

[0019] Advantageously, the finger mechanism further comprises at least one pad connected to the first portion and / or to the second portion, so that in the closed position of the finger mechanism, said pad is configured to adapt to the predefined universal gripping means device.

[0020] The pad increases the contact surface between the robotic gripper and the universal gripping device, thus improving the latter's gripping and retention in the robotic gripper.

[0021] Furthermore, due to the choice of using rigid rods to drive the movement of the fingers from the force distributor, the kinematics of the fingers is rigidly fixed, and the presence of the pads allows for damping when gripping an object. The pads thus compensate for the lack of margin, due to the use of rigid rods, when gripping objects.

[0022] Advantageously, the robotic gripper comprises a plurality of finger mechanisms connected to the force distributor.

[0023]

[0024] Advantageously, the pivot connection connecting the first portion of the finger mechanism and the force distributor has a mechanical clearance configured to allow passive alignment of the finger mechanisms between their open position and their closed position.

[0025] Advantageously, the robotic gripper forms a humanoid type robotic hand, and further comprises a thumb comprising a first portion and a second portion connected to each other and articulated by means of a link, the first portion also being connected to a system for actuating said thumb in the robotic gripper.

[0026] Advantageously, said thumb and said at least one finger mechanism are configured to cooperate with a stop of the predefined gripping means device so as to passively ensure the correct positioning of said robotic gripper with respect to the predefined gripping means device.

[0027] Alternatively, when handling light objects, the thumb can be used to passively align the predefined gripping device so that it does not move out of the path. The thumb then functions as a passive alignment organ

[0028] The invention also relates to an assembly comprising a robotic gripper as described above and at least one predefined universal gripping means device, the robotic gripper being configured to grip and / or release the universal gripping means device. PRESENTATION OF FIGURES

[0029] The invention will be better understood on reading the following description, given solely by way of example, and referring to the appended drawings given as non-limiting examples, in which identical references are given to similar objects and in which:

[0030] This is a schematic representation of the robotic gripper according to the invention, in an opening of the finger mechanisms, the robotic gripper comprising a cover for covering its operating mechanism;

[0031] This is a similar view of the robotic gripper, but in which the cover has been omitted, making the robotic gripper mechanism visible;

[0032] This is a top view of the robotic gripper, in which the finger mechanisms have been made visible;

[0033] This is a schematic representation of the assembly according to the invention comprising the robotic gripper of the, in the closed position, in which a universal gripping means device is arranged;

[0034] This is a right-hand view of the whole;

[0035] This is a top view of the whole ; and

[0036] This is a right-hand, cross-sectional view of the entire assembly, making the finger mechanisms particularly visible in a closed position of the robotic gripper.

[0037] It should be noted that the figures set out the invention in detail to enable the invention to be implemented; although not limiting, said figures serve in particular to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0038] The invention relates to a robotic gripper 1, as shown in the.

[0039] The robotic gripper 1 is configured to grip a predefined gripping means device 2.

[0040] With reference to the, the robotic gripper 1 comprises at least one finger mechanism 6, in particular three finger mechanisms 6, each connected to a body 10 composed of an operating mechanism of the robotic gripper 1 housed in a frame and covered by a cover 11. Overall, the robotic gripper 1 is in particular in the form of a robotic hand having a part substantially forming a palm of the robotic hand, and a plurality of finger mechanisms 6, in particular composed of two portions corresponding to “phalanges” in the case of a humanoid type robotic hand. The palm defines a median plane of the robotic gripper 1. This median plane comprises a median axis X, substantially contained in the plane of the palm of the robotic gripper 1, in its middle, oriented towards the fingers.

[0041] Each finger mechanism 6 here comprises two articulated portions, a first portion 61 and a second portion 62, articulated by means of a connection 60, in particular a pivot type connection.

[0042] Each finger mechanism 6 is movable between an open position and a closed position. In the open position, the first portion 60 and the second portion 62 are substantially aligned with each other. In the closed position, the second portion 62 has pivoted relative to the first portion 61, in particular to close the robotic gripper 1 in order to grasp said predefined gripping means device 2.

[0043] In addition, the robotic gripper 1 has a thumb 9, connected to the body 10.

[0044] As shown in the, one of the finger mechanisms 6 and / or the thumb 9 may comprise a side bearing 7. The side bearing 7 is configured to allow the alignment of the predefined gripping means 2 in the robotic gripper 1.

[0045] Advantageously, each of the finger mechanisms 6 and the thumb 9 comprises a lateral bearing 7.

[0046] Furthermore, each finger mechanism 6 may comprise a pad 8. The pad 8 is connected to the first portion 61 and / or to the second portion 62. In the closed position of the finger mechanism 6, each pad 8 is configured to fit the predefined universal gripping means device 2. Thus, the pad 8 makes it possible to increase the contact surface between the robotic gripper 1 and the universal gripping means device 2, thereby improving the gripping of the latter and its retention in the robotic gripper 1.

[0047] Furthermore, the thumb 9 and the finger mechanisms 6 are configured to cooperate with a stop of the predefined gripping means device 2, so as to passively ensure the correct positioning of the robotic gripper 1, with respect to the predefined gripping means device 2.

[0048] With reference to Figures 2 and 3, the thumb 9 comprises a first portion 91 and a second portion 92. The first portion 91 and the second portion 92 are connected to each other and articulated by means of a connection 93, in particular a pivot type connection.

[0049] In addition, the first portion 91 is connected to the operating mechanism of the robotic gripper 1. In particular, the first portion 91 is connected by means of a pivot-type or ball-joint-type connection, for example, to a thumb actuation system 9.

[0050] In particular, the thumb 9 actuation system may comprise a motor configured to drive a set of gears, itself configured to drive a screw allowing the thumb 9 to move around the pivot connection or around the ball joint connection.

[0051] Thus, the thumb 9 can rotate 90° to allow the gripping means device 2 to be gripped by the finger mechanisms 6, but also to allow its release. Furthermore, the thumb 9, by its movement, can allow, in cooperation with the finger mechanisms 6, the passive alignment of the gripping means device 2 in the robotic gripper 1.

[0052] The figure represents the robotic gripper of the ; only, the cover 11 has been removed, making the operating mechanism of the robotic gripper 1 visible.

[0053] With reference to the, the robotic gripper 1 further comprises at least one motor 3, at least one actuating means 4 and at least one force distributor 5.

[0054] In particular, the motor 3 is connected to the actuating means 4, itself connected to the force distributor 5. The force distributor 5 is connected to each finger mechanism 6.

[0055] The motor 3 is configured to drive the actuating means 4 so as to actuate the force distributor 5.

[0056] The force distributor 5 is configured to move the finger mechanism 6 from the open position to the closed position and vice versa. In particular, the force distributor 5 is configured to drive the first portion 61 which drives the second portion 62 around the connection 60, so that the finger mechanism 6 grips or vice versa, releases, the predefined gripping means device 2.

[0057] In other words, the force distributor 5 is configured to drive the movement of the first portion 61, which itself is configured to drive the movement of the second portion 62, via the link 60.

[0058] In addition, as shown in Figures 3 and 7, the first portion 61 comprises at least one rod 63. The rod 63 is on the one hand connected by means of a pivot-type connection 64 to the force distributor 5. The second portion 62 comprises at least one rod 65, different from the rod 63. The rod 63 of the first portion 61 and the rod 65 of the second portion 62 are connected by the connection 60 connecting the first portion 61 and the second portion 62. In particular, the rods 63, 65 are by definition rigid.

[0059] The use of rigid rods 63, 65, rather than cables, makes it possible to improve the precision of the opening and closing kinematics of the robotic gripper 1. In addition, this makes it possible to define kinematics perfectly adapted to a specific gripping means, such as a universal handle.

[0060] In the state of the art, the use of cables is preferred to induce the kinematics of opening and closing of robotic hands, because this makes it possible to adapt this opening and closing of said robotic hands to different shapes of objects to be grasped.

[0061] In the invention, the use of rigid rods 63, 65 means giving up this ability to easily adapt to different object shapes, in favor of great precision and better compactness, the robotic gripper 1 being particularly dedicated to the manipulation of objects provided with a predefined gripping means, in this case a handle.

[0062] As shown in the, the pivot-type connection 60 connecting the first portion 61 and the second portion 62 may comprise a disc 66, configured to pivot about an axis of rotation. The first portion 61 and the second portion 62 are each connected to the disc 66.

[0063] The use of the disc 66 between the first and second portions 61, 62 allows the weight of the load transmitted when the robotic gripper 1 grasps an object to be further away from the center of rotation of the fingers around the pivot links which connect them to the force distributor 5. Thus, the force distributor 5 requires movements of lesser amplitude to move the fingers, which improves the compactness of the robotic gripper 1.

[0064] With reference to the, the force distributor 5 comprises an arcuate rod 69 on which the rods 63 of the finger mechanisms 6 are connected. In particular, the rods 63 are connected to the arcuate rod 69 of the force distributor 5 by means of a pivot-type connection.

[0065] The arcuate rod 69 has a section in the form of an arc of a circle along a radius coincident with the median axis X of the robotic gripper. The arcuate rod 69 is parallel to the median plane of the robotic gripper. The arrow of the arc formed by the arcuate rod 69 is thus also coincident with the median axis X of the robotic gripper 1 and may in particular also be aligned with the middle finger.

[0066] The orientation of the arc is such that the string of the arc thus formed is on the other side of the arcuate rod 69 relative to the fingers of the robotic gripper 1.

[0067] The fact that the force distributor 5 mainly comprises such an arcuate rod 69 also makes it possible to improve the compactness of the robotic gripper.

[0068] The finger mechanisms 6 are distributed along the length of the force distributor rod 5.

[0069] The rod of the force distributor 5 is arched so that each finger mechanism 6 has a different angle when they are connected to it. This allows kinematics close to that of a human hand when gripping an object to be obtained. Thus, the finger mechanisms 6, during their movements, are not parallel to each other but concentrate towards a central point during closing.

[0070] In addition, an opening is provided in the arcuate rod 69 of the force distributor 5, so as to allow at least part of the actuating means 4 to pass through, allowing it to translate.

[0071] As shown in the, the pivot connection 64 connecting the first portion 61 of the finger mechanism 6 and the force distributor 5 has mechanical play. This mechanical play is configured to allow passive alignment of the plurality of finger mechanisms 6, here of the three finger mechanisms 6, between their open position and their closed position.

[0072] The actuating means 4, as shown in FIGS. 2 and 3 for example, may comprise at least one gear 67 and one worm screw 68.

[0073] The gear 67 is connected to the motor 3 on the one hand and to the worm screw 68 on the other hand. The worm screw 68 is connected to the force distributor 5, in particular the worm screw 68 passes through the opening made in the arcuate rod 69 of the force distributor 5, itself connected to the finger mechanisms 6.

[0074] In addition, a button can be added at the end of travel of the worm screw 68, so as to automate the calibration of the robotic gripper 1 each time the robot is switched on, the initial position of the robotic gripper being known. After calibration, the absolute position of the finger mechanisms 6 can be known at any time.

[0075] The motor 3 is configured to drive the gear 67 in rotation, itself configured to drive the worm screw 68 in translation. The worm screw 68 is then configured to drive the force distributor 5 in translation, configured to move each finger mechanism 6 from their open position to their closed position and / or from their closed position to their open position.

[0076] In addition, the motor 3 may include an encoder making it possible to control the relative position of the finger mechanisms 6 at any time.

[0077] The thread of the worm screw 68 is inclined. This inclination allows the worm screw 68 to self-lock, that is to say not to start rotating without power from the motor 3, and therefore to lock the robotic gripper in a position. Thus, the finger mechanisms 6 can grip the gripping means device by adopting the closed position and maintain this closed position, without consuming energy from the motor 3 for the entire time that the closed position is maintained. In other words, the inclination of the thread of the worm screw 68 allows the energy of the motor 3 to be consumed only when moving from the open position to the closed position and vice versa, and not when maintaining one of these two positions.

[0078] We will now describe the movement of the robotic gripper 1, in particular to move from the open position of the finger mechanisms 6 as shown in the, to a closed position as shown in the.

[0079] As shown in the, the finger mechanisms 6 are in an open position, that is to say a position in which the first portion 61 and the second portion 62 are substantially aligned with each other. To move into the closed position, the motor 3 is activated, rotating the gears 67 of the actuating means 4. The gear 67 drives the movement of the worm screw 68, which will translate in the direction of the force distributor 5, causing the translation of said force distributor 5 in the opposite direction, that is to say in the direction of the motor 3. The translation of the force distributor 5 causes the rotation about the connection 64 of the rod 63, which by its movement causes the rotation of the rod 62, causing the closing of the finger mechanisms 6.

[0080] To move from the closed position shown in the to the open position shown in the, the reverse movement is performed. In particular, the motor 3 is activated in the opposite direction to that in which it is activated to move from the open position to the closed position, rotating the gears 67 of the actuating means 4, also in the opposite direction to previously. The gear 67 drives the movement of the worm screw 68, which will translate in the opposite direction with respect to the force distributor 5, causing the translation of said force distributor 5 in the direction of the finger mechanisms 6. The translation of the force distributor 5 causes the rotation about the connection 64 of the rod 63 which, by its movement, causes the rotation of the rod 62, causing the opening of the finger mechanisms 6.

[0081] The invention also relates to an assembly comprising a robotic gripper 1, as previously described, and at least one predefined universal gripping means device 2. The robotic gripper 1 is configured to grip and / or release the universal gripping means device 2.

[0082] It will also be noted that the invention is not limited to the embodiments described above. It will indeed appear to those skilled in the art that various modifications can be made to the embodiment described above, in light of the teaching which has just been disclosed to them.

[0083] In the detailed presentation of the invention given above, the terms used should not be interpreted as limiting the invention to the embodiment set forth in this description, but should be interpreted to include all equivalents the prediction of which is within the reach of those skilled in the art by applying their general knowledge to the implementation of the teaching just disclosed to them.

Claims

A robotic gripper (1) configured to grip a predefined gripping means device (2), said robotic gripper (1) comprising: a motor (3); an actuating means (4), connected to said motor (3); a force distributor (5) connected to said actuating means (4); and at least one finger mechanism (6) connected to the force distributor (5), said finger mechanism (6) comprising at least two articulated portions (61, 62) by means of a pivot connection (60) and said finger mechanism (6) being movable between an open position in which the first portion (61) and the second portion (62) are substantially aligned with each other and a closed position in which the second portion (62) has pivoted with respect to the first portion (61),in particular to close the robotic gripper (1) in order to grasp said predefined gripping means device (2);the motor (3) being configured to drive said actuating means (4) so as to actuate the force distributor (5) which is configured to move the finger mechanism (6) from the open position to the closed position, and vice versa, by driving said first portion (61) of the finger mechanism (6) which drives said second portion (62) of the finger mechanism (6) around said pivot connection (60), so that said finger mechanism (6) grasps or, conversely, releases, the predefined gripping means device (2),the pivot connection (60), which connects the first portion (61) and the second portion (62), comprising a disc (66) configured to pivot around an axis of rotation, the first portion (61) and the second portion (62) each being connected to said disc (66),and the force distributor (5) comprising an arched rod (69),the plurality of finger mechanisms (6) being connected by means of a pivot-type connection to said arcuate rod (69) and distributed along its length., Robotic gripper (1) according to claim 1, wherein the first portion (61) comprises at least one rod (63) connected on the one hand by means of a pivot-type connection (64) to the force distributor (5), the second portion (62) comprising at least one other rod (65), the rod (63) of the first portion (61) and the rod (65) of the second portion (62) being connected by the pivot connection (60) connecting the first portion (61) and the second portion (62). Robotic gripper (1) according to any one of claims 1 to 2, wherein the actuating means (4) comprises at least one gear (67) and one worm screw (68), the gear (67) being connected to the motor (3) and to the worm screw (68) and the worm screw (68) being connected to the force distributor (5), the motor (3) being configured to drive said gear (67) in rotation, itself configured to drive said worm screw (68) in translation, configured to drive the force distributor (5) in translation configured to move the finger mechanism (6) from its open position to its closed position and / or from its closed position to its open position. Robotic gripper (1) according to any one of claims 1 to 3, wherein the finger mechanism (6) comprises at least one lateral bearing (7) configured to allow alignment of the gripping means (2) predefined in the robotic gripper (1). Robotic gripper (1) according to any one of claims 1 to 4, wherein the finger mechanism (6) further comprises at least one pad (8) connected to the first portion (61) and / or to the second portion (62), so that in the closed position of the finger mechanism (6), said pad (8) is configured to fit the predefined universal gripping means device (2). Robotic gripper (1) according to any one of claims 1 to 5, comprising a plurality of finger mechanisms (6) connected to the force distributor (5). A robotic gripper (1) according to claim 6, wherein the pivot link (64) connecting the first portion (61) of the finger mechanism (6) and the force distributor (5) has a mechanical clearance configured to allow passive alignment of the finger mechanisms (6) between their open position and their closed position. Robotic gripper (1) according to any one of claims 1 to 7, forming a humanoid type robotic hand, further comprising a thumb (9) comprising a first portion (91) and a second portion (92) connected to each other and articulated by means of a link (93), the first portion (91) also being connected to a system for actuating said thumb (9) in the robotic gripper (1). Robotic gripper (1) according to claim 8, wherein said thumb (9) and said at least one finger mechanism (6) are configured to cooperate with a stop of the predefined gripping means device (2) so as to passively ensure the correct positioning of said robotic gripper (1) with respect to the predefined gripping means device (2). An assembly comprising a robotic gripper (1) according to any one of claims 1 to 9 and at least one predefined universal gripping means device (2), the robotic gripper (1) being configured to grip and / or release the universal gripping means device (2).

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