EP4076868A1 - Dispositif de préhension, robot et procédé de commande - Google Patents

Dispositif de préhension, robot et procédé de commande

Info

Publication number
EP4076868A1
EP4076868A1 EP20841713.9A EP20841713A EP4076868A1 EP 4076868 A1 EP4076868 A1 EP 4076868A1 EP 20841713 A EP20841713 A EP 20841713A EP 4076868 A1 EP4076868 A1 EP 4076868A1
Authority
EP
European Patent Office
Prior art keywords
gripping
elements
gripping device
gripper
gripper elements
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP20841713.9A
Other languages
German (de)
English (en)
Inventor
Daniel Wahrmann LOCKHART
Andreas SPENNINGER
Jose Ramon Medina HERNANDEZ
Christoph KUGLER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Franka Emika GmbH
Original Assignee
Franka Emika GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Franka Emika GmbH filed Critical Franka Emika GmbH
Publication of EP4076868A1 publication Critical patent/EP4076868A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J15/00—Gripping heads and other end effectors
    • B25J15/0028—Gripping heads and other end effectors with movable, e.g. pivoting gripping jaw surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J15/00—Gripping heads and other end effectors
    • B25J15/02—Gripping heads and other end effectors servo-actuated
    • B25J15/0253—Gripping heads and other end effectors servo-actuated comprising parallel grippers
    • B25J15/026—Gripping heads and other end effectors servo-actuated comprising parallel grippers actuated by gears
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J15/00—Gripping heads and other end effectors
    • B25J15/08—Gripping heads and other end effectors having finger members
    • B25J15/12—Gripping heads and other end effectors having finger members with flexible finger members

Definitions

  • the present invention relates to a gripping device for gripping objects, in particular for robots and manipulators, a robot using them, and a control method for gripping objects by means of a gripping device of a robot.
  • Gripping devices as parallel grippers with two linearly movable grippers or finger elements, as centric grippers with at least three finger elements or as angular grippers with offset grippers for robots are known in a wide variety of configurations.
  • the gripping devices can also be designed so that they enable a linear or claw grip, in which an object is gripped by the gripper of the gripping device only at two individual points, or that they essentially completely surround the object with the grippers or Allow spatial gripping by adapting the grippers or finger elements of the gripping device to the contour of the object to be gripped, if necessary.
  • a gripping device which can be designed as a parallel or centric gripper, in which the grippers are designed as double arms in order to implement a transmission with a parallelogram guide.
  • This makes it possible, on the one hand, to hold objects towards one another by a linear movement of the grippers, or, on the other hand, to partially enclose curved objects by allowing the upper distal ends of the grippers to tilt around the object.
  • Which type of gripping is ultimately used depends on the size and shape of the object to be gripped and the construction, ie the level of equilibrium established between the finger elements due to the transmission. In principle, this enables a resilient, adapted gripping of the object, although the resilient and adaptive capabilities are considerably limited due to the design.
  • the mechanical structure of the transmission with lever elements, swivel joints, springs and actuators is complex and susceptible and also leads to a high weight of the entire gripping device.
  • the gripping device shown in the US patent also has finger elements in which the inner surfaces facing the object consist of a chain of individual links movable relative to one another, so that a flexible gripping that can be adapted to the contour of the object to be gripped is permitted.
  • a gripping device in which the finger elements or grippers are designed as so-called fin beam elements with two flexurally flexible surfaces, the surfaces being connected to one another at their free ends and being attached to a gripper base at a distance from one another forming a triangular arrangement are.
  • the two surfaces are connected to one another via several lamellae running parallel to one another, each of which is articulated or articulated at its end regions are cohesively and resiliently connected to the surfaces, so that when an object is gripped, the surfaces are formed onto the surface of the object, since the surfaces can be moved relative to one another via the lamellae.
  • the flexibility properties of such a gripping device are limited due to the design.
  • the finger elements must be actuated in their entirety for gripping and thereby moved in a deformable manner, whereby additional torques and forces act on the mechanism.
  • Gripping devices as described above, are designed, if at all, only for this type of parallel grip.
  • Such gripping usually fails in the case of flat, soft objects, since a section of the object that is present above the fingers moving in parallel cannot be securely grasped by them.
  • a safe, non-destructive gripping of flexible, flat objects by means of parallel grippers cannot be implemented or, if at all, only with a disproportionately high effort.
  • an object of the invention to provide an improved gripping device, in particular for robots of lightweight construction, which is easy to operate, versatile and also inexpensive to manufacture and which in particular allows the gripping of objects that are mostly flat and are designed to be compliant in themselves.
  • the invention proposes a gripping device for gripping objects with at least two gripping units, each of which has a gripping finger and can be transferred by a controlled movement between a release position and a gripping position that grips the object, the gripping units each having gripper elements that are in the gripping position with can be brought into contact with the object to be gripped, and wherein the gripper elements are rotatably mounted on the distal ends of the gripping fingers.
  • the gripping device according to the invention should be provided for gripping non-rigid or non-rigid objects from a flat surface.
  • objects are understood here that are inherently flexible or elastic and have a flat extension, such as any type of textiles, webs of fabric, plastic films, sheets of paper, insulating materials and the like.
  • the gripper elements are provided on the gripper fingers as independent elements, so to speak as a kind of rotating jaws, whereby the rotatable mounting according to the invention allows that when the gripper elements are in contact with the objects to be gripped, which are usually to be picked up by a flat surface, such as a conveyor belt, these objects function in connection with the base itself as a kind of abutment on which the gripper elements can roll with intermediate storage or with jamming of the object.
  • the force on which the clamping is based ie the force with which the gripping fingers are intended to act on the object or the substrate via the additional gripping elements, as well as the lateral movement of the gripping fingers towards one another, which due to the frictional effect between the object and the gripping elements a rotational movement of these gripper elements can be carried out in a preferred manner by a flexibly regulated and therefore sensitive robot, in particular a lightweight construction.
  • the control behavior of such a robot which can be adjusted to this function, enables the non-destructive gripping of soft materials such as textiles.
  • the robot is in particular able to "feel" whether the gripper elements are correspondingly resting on such an object and whether the object can actually be gripped by means of the gripper elements then rotating towards one another in the course of the parallel movement of the gripping fingers.
  • the gripping elements are designed to move toward and away from each other To be able to turn away from the object to be gripped when the gripper elements come to rest against each other when they reach the gripping position.
  • the gripper elements have a first section, the outer contour of which is configured in relation to their axis of rotation in such a way that contact between the gripper elements takes place linearly after they have been moved towards one another.
  • the outer contour of the first section in relation to the axis of rotation partly follows the shape of a mathematical spiral, which is characterized in that the mutual contact point lies above the common plane occupied by the axes of rotation of both gripper elements, such as an Archimedes spiral .
  • the gripper elements according to the invention can have a second section, the outer contour of which is designed in relation to their axis of rotation in such a way that when the gripping position is completed, further rotation of the gripper elements is prevented, in particular that, when the gripping position is completed, the gripper elements are at least partially flat with the object engaging face each other.
  • the gripper elements can be pretensioned.
  • the gripper elements can have a device which is designed to prevent rotation of the gripper elements when they are not in contact. This device can also be set up to convert the gripper elements into a To offset rotation away from each other when there is no longer any contact between the gripper elements, so as to support the release of the gripped object and also to return the gripper elements to their starting position.
  • a torsion spring in combination with a mechanical stop or a similar mechanism is conceivable to ensure that the rotary movement does not start before the gripper elements come into contact, i.e. that an accidental rotation, e.g. in the event of a collision with a work surface or the gripped object, is fundamentally prevented .
  • At least one of the gripper elements is designed to be rotatably drivable by an actuator. In this way, it is possible, via a frictional engagement of the gripper element with the flat object, to shift and thus raise it by actively rotating it with respect to, for example, the opposing gripper element, which then serves as an abutment for this purpose.
  • the gripping fingers have a gear mechanism for driving the gripping elements, e.g. a belt drive that is guided inside the gripping finger.
  • the outer surface of the gripper elements has a friction-increasing coating and / or structure, such as a rubber coating, if necessary with knobs, lamellae or the like.
  • the invention also relates to a robot that has a gripping device according to one of the preceding Has designs, preferably the lightweight design for use in the course of a human-robot collaboration (HRC).
  • HRC human-robot collaboration
  • the invention also relates to a control method for gripping a preferably inherently flexible object by means of a robot, which has a gripping device according to one of the configurations described above, comprising the steps:
  • the gripper elements according to the invention have such a shape and such a mounting on the distal ends of the gripping fingers that they automatically set themselves in rotation when they come into contact with one another, an adjustable, depending on the weight of the object to be gripped, is sufficient. Slow linear movement of the gripper fingers towards one another without great effort in order to pick up the object between the rotating rotating jaws.
  • the movement of the gripping fingers towards one another, especially when the rotating jaws are in contact, can be flexibility-controlled for the execution with an active drive, this control being coordinated accordingly with the further control of the robot guiding the gripping device.
  • the method can have the further step:
  • the method according to the invention is characterized in that the steps can be carried out by a flexible and / or sensitively controlled robot, the control of which is set up accordingly in this regard with regard to the gripping devices used.
  • the solutions according to the invention are based on utilizing the flexible nature of the object to be gripped.
  • the mechanism By “pulling" the object between the gripper elements of the fingers of the gripping devices through a rotating, friction-intensive surface, the mechanism ensures correct, above all non-destructive gripping.
  • the gripper elements of the robot gripper can pivot about their axes, which are both parallel to one another and parallel to the plane on which the object is located.
  • the outer contour of the respective surface of the gripper elements that comes into contact with the flexible object follows the shape of a mathematical spiral, such as an Archimedean spiral with a contact point located above the common plane of the two axes.
  • a mathematical spiral such as an Archimedean spiral with a contact point located above the common plane of the two axes.
  • the mechanical lever causes the rotating jaws to rotate in opposite directions about their respective axis.
  • the object is deformed into the seat between the fingers and a correct grip is ensured by controlling the gripping force. After a turn through a certain angle, preferably half a turn, a flat-shaped vertical contact surface reached and the rotation of the turning jaws stopped automatically.
  • FIG. 1 shows an example of a prior art gripping device
  • FIGS. 2 to 5 show a first embodiment of a gripping device according to the invention, each figure showing a gripping step of the method according to the invention
  • FIG. 1 a gripping device from the prior art is shown by way of example, which can be attached to a distal end of a multi-link manipulator of a flexibly controlled robot.
  • the gripping device consists of a base 1, in which there is a drive mechanism and a guide for the gripping fingers 4, with a flange 2 for attachment to the robot arm, not shown, and a connection 3 for controlling the drive of the gripping fingers 4, which can be moved linearly towards one another have gripping jaws 5 at their distal ends.
  • these gripping fingers 4 only allow a parallel grip, with which flat, soft objects, such as textiles, arranged on a flat surface cannot be gripped.
  • Figures 2 to 5 show a first embodiment of a gripping device according to the invention, with which a gripping such objects can be realized in a simple manner.
  • FIG. 2 shows a gripping device in a first embodiment according to the invention, the state being shown in which the gripping device comes to rest on the flexible object to be gripped, as indicated by the vertical arrow.
  • the soft and flat object 7 to be gripped, a textile material, is placed on a flat base 6.
  • the gripping device also has two gripping fingers 8, which can be moved parallel to one another, as indicated by the horizontal arrows.
  • both gripping fingers 8 each have a rotatably mounted gripper element in the form of rotating jaws 9, which are provided with a friction-enhancing coating 10 on their outer surface, which are intended to come into contact with the object 7.
  • a means 11 which prevents rotation and is designed, for example, as an appropriately dimensioned one-way spring.
  • the outer contour in a first section 9.1 of the rotary jaws 9 follows the line of an Archimedes spiral, so that as the linear movement progresses, the rotary jaws 9 come into contact with one another at a point K, which is above a common plane which is formed by the pivot points D of the bearings of the rotary jaws 9.
  • this has the effect that the rotary jaws 9 begin to rotate as soon as they touch at point K, and as a result of friction and adhesion, more and more material of the object 7 is taken up between the rotary jaws 9, when these continue to rotate and their sections 9.1 roll off one another with the object 7 being interposed, as shown in FIG. 4, which is induced by a further linear movement of the gripping fingers 8 towards one another.
  • FIG. 5 shows a state in which the gripping fingers 8 have finally arrived in their closed position and the rotary jaws 9 have reached their final gripping position. Following their first section 9.1, the rotating jaws 9 have, viewed in the direction of rotation, a second section 9.2 which is linear, as indicated in FIG. 4.
  • these sections 9.2, including the object 7 lie flat opposite one another at this point. This results in an areal load with increased frictional engagement, as a result of which the object 7 can be held securely.
  • the object 7 can now be lifted by the robot and transferred to a target position, where it is then subsequently released by the gripping fingers 8 moving linearly apart and the rotating jaws 9, if necessary supported by the spring means 11, back in their opposite direction Turn the starting position.
  • the shown mechanism of gripping the gripping device according to the invention makes use of the flexibility of the object 7. It does not depend on precise gripping positions and is therefore more robust against visual defects, for example if additional optical sensors are to be used in connection with the robot. Correct and non-destructive gripping of flexible objects of any desired, preferably flat design, is carried out according to the invention predominantly by force control in relation to the linear movement of the gripping fingers 8.
  • FIGS. 6 to 7b schematically show a second embodiment according to the invention.
  • a gear and drive mechanism 12 is used, which can be designed in any design inside at least one gripping finger 13 and the base 14 of the gripping device.
  • the rotary jaw 15 can be driven via a belt drive 16 arranged inside the gripping finger 13, which in turn is actuated by a gear 17 rolling on a rack 18 inside the base 14 and is thereby set in rotation when the gripping fingers 13 themselves are moved linearly towards one another or away from one another.
  • the linear movement of the gripping fingers 13 towards each other and the simultaneous rotary movement of the rotary jaws 15, as indicated by the arrows accumulate a flexible object 19 at a corresponding point and pull it up between the rotary jaws 15 and thereby gripped.
  • This embodiment of the gripping device is suitable for heavier objects 19 of this type, it also being possible for the gripping device as such to be dimensioned correspondingly larger.
  • the object to be gripped has flexible properties.
  • the mechanism ensures correct and non-destructive gripping.
  • the rotary movement of the rotary jaws 15 is coupled to the linear movement of the gripping fingers 13, so that no additional motor is required.
  • the object 19 is deformed between the rotary jaws 15 and the actual gripping force is controlled by the linear movement of the gripping fingers 13. By checking the distance between the gripping fingers 13, unsuccessful gripping attempts can easily be recognized and responded to.
  • a gripping device is particularly suitable for use with an HRC robot that has a corresponding compliance control that is able to implement such a "sensing" gripping of a flat, filigree object, for example, by the gripping device and the robot.

Landscapes

  • Engineering & Computer Science (AREA)
  • Robotics (AREA)
  • Mechanical Engineering (AREA)
  • Manipulator (AREA)

Abstract

L'invention concerne un dispositif de préhension pour un robot de préhension d'objets (7, 19). Selon l'invention, des éléments de préhension (9, 15) sont montés rotatifs sur les doigts de préhension du dispositif de préhension.
EP20841713.9A 2019-12-22 2020-12-22 Dispositif de préhension, robot et procédé de commande Withdrawn EP4076868A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102019008939.1A DE102019008939A1 (de) 2019-12-22 2019-12-22 Greifvorrichtung und Roboter sowie Steuerungsverfahren
PCT/EP2020/087717 WO2021130282A1 (fr) 2019-12-22 2020-12-22 Dispositif de préhension, robot et procédé de commande

Publications (1)

Publication Number Publication Date
EP4076868A1 true EP4076868A1 (fr) 2022-10-26

Family

ID=74183121

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20841713.9A Withdrawn EP4076868A1 (fr) 2019-12-22 2020-12-22 Dispositif de préhension, robot et procédé de commande

Country Status (7)

Country Link
US (1) US20230028437A1 (fr)
EP (1) EP4076868A1 (fr)
JP (1) JP2023507827A (fr)
KR (1) KR20220122690A (fr)
CN (1) CN114945448A (fr)
DE (1) DE102019008939A1 (fr)
WO (1) WO2021130282A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022111500A1 (de) 2022-05-09 2023-11-09 Rational Aktiengesellschaft Greifvorrichtung, Handhabungsgerät und Baugruppe

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2543119A1 (fr) * 1983-03-25 1984-09-28 Letard Michel Dispositif de prise d'une feuille superieure sur une pile de feuilles en matiere souple
US5960689A (en) * 1998-10-27 1999-10-05 Warren Metallurgical Inc. Bar puller
US6554337B2 (en) * 2000-12-07 2003-04-29 Homayoon Kazerooni Mechanical grapple for grabbing and holding sacks and bags
DE602006004021D1 (de) * 2006-06-01 2009-01-15 Punch Graphix Int Nv Vorrichtung und Verfahren zum Greifen von Papier
DE102009015975B4 (de) * 2009-03-26 2012-01-05 Festo Ag & Co. Kg Fluidtechnisches Gerät, insbesondere Greifervorrichtung
WO2013075245A1 (fr) * 2011-11-25 2013-05-30 Robotiq Inc. Appareil de préhension comprenant un doigt mécanique sous-actionné à deux degrés de liberté permettant la préhension par enserrage et par pincement
JP5480340B2 (ja) * 2012-07-26 2014-04-23 ファナック株式会社 ローラ装置を用いた取出しロボットシステム
CA2964199C (fr) * 2014-09-12 2023-04-04 Polyvalor, Limited Partnership Doigt mecanique pour appareil de prehension
US10259122B2 (en) * 2015-03-05 2019-04-16 President And Fellows Of Harvard College Compliant adaptive robot grasper
US9533419B1 (en) * 2015-11-02 2017-01-03 Google Inc. Robotic finger and hand
WO2019028146A1 (fr) * 2017-08-02 2019-02-07 Berkshire Grey, Inc. Systèmes et procédés d'acquisition et de déplacement d'objets présentant des surfaces extérieures complexes
JP7248704B2 (ja) * 2018-01-15 2023-03-29 インワテック エーピーエス 把持部を用いて布片を把持し、移動させかつ解放するための方法および把持部

Also Published As

Publication number Publication date
KR20220122690A (ko) 2022-09-02
DE102019008939A1 (de) 2021-06-24
WO2021130282A1 (fr) 2021-07-01
JP2023507827A (ja) 2023-02-27
CN114945448A (zh) 2022-08-26
US20230028437A1 (en) 2023-01-26

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