JP2019010717A - Robot hand - Google Patents

Abstract

To provide a robot hand with a simple structure that is specialized in a picking work having a work process of storing a gripped work into a narrow storage space.SOLUTION: A robot hand 7 includes a pair of fingers 76a, 76b supported to a proximal part 72 so as to be movable in a direction of coming close to and separating from each other. The fingers 76a, 76b are formed into an elongated body with a recessed cross section or L-shaped cross section and fitted with pads 77a, 77b at the inner surfaces thereof.SELECTED DRAWING: Figure 3

Description

  Embodiments described herein relate generally to a robot hand equipped in a robot arm.

  Robot devices are applied in various fields such as production lines, medical care and nursing care, and are expected to be applied in further fields in the future. In recent years, expectations for so-called collaborative robots that work near workers have been increasing against the background of a predicted decrease in the working population. By introducing a collaborative robot, the collaborative robot can replace the worker when there is a shortage of workers. However, when the collaborative robot is in charge of work, it may be necessary to use a tool dedicated to the collaborative robot different from the one used by the worker. In that case, in the entire manufacturing process, there is a possibility that work efficiency is deteriorated, a subsequent process is changed, and the like. Therefore, in order to eliminate the need for a dedicated tool for the collaborative robot, a robot hand specialized for the work in charge is required. For example, a workpiece that has protrusions on the surface and cannot be stacked up and down, such as a board on which components are mounted, is stored by vertical insertion in a return box whose interior is vertically and horizontally partitioned by a plurality of partitions. As a result, the surface on which the component is mounted can be protected, and a plurality of workpieces can be stored in the return box without interfering with each other. However, from the viewpoint of manufacturing efficiency, the larger the number of workpieces that can be stored in one return box, the better. The storage space for workpieces is slightly larger than the workpiece and is narrow. For this reason, the worker takes the work that has been transported to the picking position with one hand, and with the other hand extending the partition so that the opening of the storage space is widened, the work taken in the hand is placed in the storage space. Store. On the other hand, for example, a picking robot including a conventional two-fingered robot hand grips a workpiece with the robot hand, moves the workpiece upward above the storage space, and then releases the workpiece. Although it is aligned above the storage space, the released work may be caught in the opening of the storage space, and the work and the partition of the return box may be damaged.

  The object is to realize a robot hand specialized in picking work including a work stage of storing a gripped work in a storage space with a simple structure.

  The robot hand according to the present embodiment includes a pair of fingers that are supported by a base so as to be movable in directions toward and away from each other. Each of the fingers has an elongated body having a concave cross section or an L cross section. The pad is attached.

FIG. 1 is an external view of a robot system in which a robot arm mechanism equipped with a robot hand according to the present embodiment is arranged. FIG. 2 is an external perspective view of the robot arm mechanism equipped with the robot hand according to the present embodiment. FIG. 3 is a top perspective view of the robot hand according to the present embodiment. FIG. 4 is a lower perspective view of the robot hand of FIG. FIG. 5 is a side view of the robot hand of FIG. FIG. 6 is a diagram showing a gripping state of the workpiece by the robot hand of FIG. FIG. 7 is a diagram showing a gripping state of the workpiece by the robot hand of FIG. FIG. 8 is a diagram illustrating a transfer stage by the robot hand of FIG. 3. FIG. 9 is a diagram illustrating a first stage of a release operation by the robot hand of FIG. FIG. 10 is a diagram illustrating a second stage of the release operation by the robot hand of FIG. FIG. 11 is a diagram illustrating a third stage of the release operation by the robot hand of FIG. FIG. 12 is a diagram illustrating a fourth stage of the release operation by the robot hand of FIG. FIG. 13 is a diagram illustrating a fifth stage of the release operation by the robot hand of FIG. FIG. 14 is a diagram illustrating a workpiece transfer state by the robot hand of FIG. 8. FIG. 15 is a diagram illustrating a workpiece transfer state by the robot hand of FIG. 8. FIG. 16 is a plan view of the returnable box of FIG. FIG. 17 is a diagram illustrating a robot hand according to a first modification of the present embodiment. FIG. 18 is a diagram illustrating a robot hand according to a second modification of the present embodiment. FIG. 19 is a diagram illustrating a robot hand according to a third modification of the present embodiment. FIG. 20 is a diagram illustrating a robot hand according to a fourth modification of the present embodiment. FIG. 21 is a diagram illustrating a robot hand according to a fifth modification example of the present embodiment. FIG. 22 is a diagram illustrating a robot hand according to a sixth modification of the present embodiment.

  Hereinafter, the robot hand 7 according to the present embodiment will be described with reference to the drawings. The robot hand 7 according to the present embodiment is mainly used by being mounted on the wrist typically at the tip of the robot arm. In the following description, a polar coordinate type robot arm mechanism equipped with the robot hand 7 according to the present embodiment and having a linear motion telescopic joint will be described as an example. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

  FIG. 1 is an external view of a robot system provided with a robot arm mechanism 100 equipped with a robot hand 7 according to the present embodiment. As shown in FIG. 1, the picking robot is arranged in the vicinity of the belt conveyor 300 in the factory. The robot hand 7 is typically attached to the wrist of the tip of an arm of a picking robot that performs a picking operation. The return box 400 is disposed in the vicinity of the picking robot. The inside of the returnable box 400 is partitioned vertically and horizontally by a plurality of partition plates, thereby forming a plurality of storage spaces. The workpiece 200 conveyed to the picking position is gripped by the belt conveyor 300 by the robot hand 7 according to the present embodiment, and stored in the storage space of the return box 400 arranged in the vicinity of the picking robot.

  FIG. 2 is an external perspective view of the robot arm mechanism 100 of FIG. The robot arm mechanism 100 includes a substantially cylindrical column portion 2, a undulating portion 4 placed on the upper portion of the column portion 2, an arm portion 5 extending from the undulating portion 4, and a wrist attached to the tip of the arm portion 5. Part 6 is provided. A hand attachment portion (not shown) is provided on a rotation portion of a wrist portion 6 of a sixth rotation axis RA6 described later. The robot hand 7 (hand effector) is attached to the hand attachment portion.

  The robot arm mechanism 100 has a plurality of joints, here six joints J1, J2, J3, J4, J5, and J6. The first, second, and third joint portions J1, J2, and J3 are called root three axes that change the position of the wrist portion 6, and are the main components of the first, second, and third joint portions J1, J2, and J3. Is accommodated in the column 2. The fourth, fifth, and sixth joint portions J4, J5, and J6 are mainly referred to as wrist three axes that change the posture of the robot hand 7 (hand effector), and the fourth, fifth, and sixth joint portions J4 and J6. The main components of J5 and J6 are accommodated in the wrist 6.

  The first joint portion J1 is a torsional rotary joint portion for turning provided with a rotation axis RA1 parallel to the vertical direction, and the arm portion 5 is turned to the left and right by the rotation of the first joint portion J1. The second joint portion J2 is a torsional rotary joint portion for raising and lowering having a rotation axis RA2 orthogonal to the rotation axis RA1, and the arm portion 5 is raised and lowered by the rotation of the second joint portion J2. The third joint portion J3 is provided by a linear motion expansion / contraction mechanism. The linear motion expansion / contraction mechanism has a structure newly developed by the inventors, and is clearly distinguished from a so-called conventional linear motion joint in terms of a movable range. The arm part 5 of the third joint part J3 extends and contracts along the expansion axis RA3. Thus, the root three axes are composed of the torsional joint for turning, the torsional joint for undulation, and the linear motion expansion / contraction mechanism. That is, the robot arm mechanism 100 shown in FIG. 2 has a polar coordinate shape.

  The fourth to sixth joint portions J4 to J6 are each provided with three orthogonal rotation axes RA4 to RA6. The fourth joint portion J4 is a torsional rotation joint portion having a rotation axis RA4 substantially coincident with the telescopic axis RA3, and the robot hand 7 is swung and rotated by the rotation of the fourth joint portion J4. The fifth joint portion J5 is a bending rotation joint portion around the rotation axis RA5 arranged perpendicular to the rotation axis RA4, and the robot hand 7 is tilted and rotated by the rotation of the fifth joint portion J5. . The sixth joint portion J6 is a torsional rotational joint portion around the rotational axis RA6 arranged perpendicular to the rotational axes RA4 and RA5, and the robot hand 7 is pivoted by the rotation of the sixth joint portion J6. It is rotated.

  Thus, the robot hand 7 is moved to an arbitrary position by the first, second, and third joint portions J1, J2, and J3, and is in an arbitrary posture by the fourth, fifth, and sixth joint portions J4, J5, and J6. Be placed. In particular, the length of the extension / contraction distance of the arm portion 5 of the third joint portion J3 enables the robot hand 7 to reach a wide range of objects from the proximity position of the support column 2 to the remote position. The third joint portion J3 is a characteristic point that is different from the conventional linear motion joint in the linear expansion / contraction operation realized by the linear motion expansion / contraction mechanism constituting the third joint portion J3 and the length of the expansion / contraction distance.

  Hereinafter, the structure of the robot hand 7 according to the present embodiment will be described with reference to FIGS. 3 to 7. FIG. 3 is an upper perspective view of the robot hand 7 according to the present embodiment. 4 is a plan view of the robot hand of FIG. FIG. 5 to FIG. 7 are diagrams showing the gripping state of the workpiece 200 by the robot hand 7 of FIG.

  The robot hand 7 has a base 72 that is typically a rectangular parallelepiped. An adapter plate 71 for connecting to the hand mounting portion of the wrist 6 is attached to the upper surface of the base 72. A pair of fingers 76a and 76b for gripping the workpiece 200 are supported on the front surface of the base portion 72 so as to be movable in a direction approaching and separating from each other. The fingers 76a and 76b are concave long bodies having the same size, and are arranged in parallel so that the inner surfaces face each other. The pair of fingers 76 a and 76 b are parallel to the adapter plate 71. Pads 77a and 77b are attached to the fingers 76a and 76b, respectively. The pad 77a is attached to the inner surface on the base side close to the base 72 of the finger 76a. Similarly, a pad 77b is attached to the inner surface of the finger 76b on the base side. Each of the pads 77a and 77b is an elastic body, more specifically, a plate-like body made of rubber or synthetic resin having sponge-like bubbles. Each of the pads 77a and 77b may be a bag body that can be expanded and contracted.

  Each of the fingers 76a and 76b is in the form of a long body having a concave cross section, in other words, a half cylinder in which a rectangular cylinder is vertically asymmetrically split. The finger 76a has a side plate 761a. The side plate 761a holds a lower plate 762a and an upper plate 763a, which is wider than the lower plate 762a, in parallel. Similarly, the finger 76b has a side plate 761b, and a lower plate 762b and a wider upper plate 763b are held parallel to the side plate 761b.

  A rail 74 is provided on the front surface of the base 72 in parallel with the width direction (left-right direction). A pair of sliders (not shown) are fitted into the rail 74, and a pair of fingers 76a and 76b are fixed to the pair of sliders. An air chuck is built into the hollow interior of the base 72 as an actuator for driving the pair of fingers 76a and 76b. The air chuck includes an air cylinder. The tip of the air tube introduced into the hollow inside of the base 72 is connected to the air cylinder via a tube hole 73 formed in the right side surface of the base 72. The rear end of the air tube is connected to a compressor. When the compressor is driven, the pair of fingers 76 a and 76 b approach or separate along the width direction of the base 72 by the air chuck. For example, when a negative pressure is supplied to the air cylinder, the pair of fingers 76a and 76b are separated from each other, and when a positive pressure is supplied, the pair of fingers 76a and 76b approach each other.

  As shown in FIGS. 5 to 7, the robot hand 7 grips the workpiece 200 by the pair of fingers 76a and 76b approaching each other and the pair of elastic pads 77a and 77b sandwiching the workpiece 200 from both sides. The dimensions of the fingers 76a and 76b and the elastic pads 77a and 77b are determined according to the size and shape of the workpiece 200 to be grasped. In order for the pair of fingers 76a and 76b to exhibit the shooter function and the tray function, the length of the pair of fingers 76a and 76b is slightly longer than the total length of the workpiece 200, and the upper plates 763a and 763b of the pair of fingers 76a and 76b The width is set so that the upper plates 763a and 763b separate a slight gap so that the workpiece 200 does not fall with the pair of fingers 76a and 76b closest to each other. In order to exert the grip function of the pair of fingers 76a, 76b, the elastic pads 77a, 77b are thinner than the depth of the fingers 76a, 76b, and the width of the lower plates 762a, 762b of the pair of fingers 76a, 76b is The upper plates 763a and 763b are set so as to separate a gap slightly wider than the entire width of the workpiece 200 in a state where the 76a and 76b are farthest apart.

  The effects of the robot hand 7 according to the first embodiment will be described with reference to FIGS. The effect of introducing the robot hand 7 according to the present embodiment is exhibited mainly at the stage of transporting the workpiece 200 and the stage of storing the workpiece 200 in the storage space 403. FIG. 8 is a diagram illustrating a transfer stage of the workpiece 200 by the robot hand 7 according to the present embodiment. 9 to 13 show first to fifth stages of the release operation by the robot hand 7, respectively. FIG. 14 and FIG. 15 are diagrams respectively showing the conveyance state of the workpiece 200 by the robot hand 7 of FIG. FIG. 16 is a plan view of the returnable box of FIG. Here, the workpiece 200 is stored vertically in the storage space 403 of the returnable box 400. The returnable box 400 includes a box body 401 whose upper side is open and a plurality of partition plates 402 that partition the box body 401 vertically and horizontally. A section partitioned by the partition plate 402 is referred to as a storage space 403. Here, the partition plate 402 is made of an elastic resin and is deformed by an external force.

  As shown in FIG. 8, the robot hand 7 holding the workpiece 200 is moved to above the storage space 403 in the transport posture. As shown in FIGS. 14 and 15, the conveying posture is such that the pair of fingers 76a and 76b face the horizontal direction, and the wide upper plates 763a and 763b of the pair of fingers 76a and 76b are narrow lower plates 762a, The posture is located below 762b. In the transport posture, the wide upper plates 763a and 763b of the pair of fingers 76a and 76b function as a flat tray. Since the elastic pads 77a and 77b are arranged on the base side of the pair of fingers 76a and 76b, the rear end side of the workpiece 200 is held between the pair of fingers 76a and 76b. Therefore, the tip side of the workpiece 200 is likely to swing up and down, and the posture of the workpiece 200 is not stable. Further, the workpiece 200 may be deformed or the workpiece 200 may move due to vibration during conveyance or the weight of the workpiece. However, a flat tray constituted by the wide upper plates 763a and 763b of the pair of fingers 76a and 76b is positioned below the workpiece 200 held by the pair of fingers 76a and 76b. Can be supported. Further, even if the workpiece 200 is dropped from the pair of fingers 76a and 76b during conveyance, the dropped workpiece 200 can be received by the tray, and the workpiece 200 is prevented from being damaged due to the workpiece 200 falling to the ground. can do. Further, the workpiece 200 held between the pair of fingers 76a and 76b does not protrude outside the rectangular parallelepiped frame defined by the outer shape of the pair of fingers 76a and 76b. Thereby, even when an obstacle collides with the robot hand 7 during conveyance, the risk of breakage of the workpiece 200 is reduced by the rectangular parallelepiped frame defined by the outer shape of the pair of fingers 76a and 76b. The As described above, the pair of fingers 76a and 76b of the robot hand 7 according to the present embodiment has both the function of gripping the workpiece 200 and the function of stabilizing the posture of the gripped workpiece 200 and preventing the fingers from falling off. . As a result, the robot hand 7 according to the present embodiment may be able to pick up a workpiece that is difficult to pinch, for example, a workpiece with poor weight balance or a deformable workpiece such as a retort pouch by pinching.

  As shown in FIG. 9, the robot hand 7 is lowered toward the storage space 403 in the release posture. The release posture is a posture in which the tip side of the robot hand 7 is inclined downward with respect to the transport posture. As shown in FIG. 10, the lowered robot hand 7 comes into contact with the partition plate 402 of the box 400 through which the outer surface of the tray formed by the wide upper plates 763 a and 763 b of the pair of fingers 76 a and 76 b passes. As shown in FIG. 11, when the robot hand 7 is further lowered from the state in which the outer surface of the tray of the robot hand 7 is in contact with the partition plate 402, the partition plate 402 is deformed outward along the inclined tray. Is done. By the downward movement of the robot hand 7, as shown in FIG. 16, the opening of the storage space 403 is pushed wide by the tray. As shown in FIG. 12, the workpiece 200 is released in a state where the opening of the storage space 403 is expanded. The released work 200 falls along the inclined tray toward the opening of the fully expanded storage space 403. Since the pair of elastic pads 77a and 77b holding the workpiece 200 are respectively arranged on the base side of the inner surfaces of the pair of fingers 76a and 76b, the pair of elastic pads 77a and 77b are formed on the inner surfaces of the pair of fingers 76a and 76b. The possibility that the released workpiece 200 is caught by the pair of elastic pads 77a and 77b can be reduced as compared with the case where the workpiece 200 is disposed on the front end side or the entire inner surface. Thereby, the smooth fall of the workpiece | work 200 is implement | achieved. As shown in FIG. 13, the released work 200 is stored in the storage space 403 without being caught by the opening of the storage space 403.

  As described above, the pair of fingers 76a and 76b of the robot hand 7 according to the present embodiment stabilizes the function of gripping the workpiece 200 (grip function) and the posture of the workpiece 200 being transported to the ground. The function of suppressing the fall (tray function) and the function of guiding the released work 200 to the storage space 403 (shooter function) are combined. This shooter function is improved by disposing the pair of elastic pads 77a and 77b on the base side of the inner surfaces of the pair of fingers 76a and 76b, respectively. Further, if the partition plate 402 constituting the storage space 403 is deformed or movable, the pair of fingers 76 a and 76 b deform or move the partition plate 402 while holding the workpiece 200, and Acts as another finger to widen the opening. These functions are realized by devising the shape of the pair of fingers 76a and 76b equipped in the robot hand 7 and the mounting position of the elastic pads 77a and 77b. That is, according to the robot hand 7 according to the present embodiment, it is possible to realize a robot hand specialized for picking work including a work stage of storing the gripped work in the storage space with a simple structure.

  The shape of the pair of fingers 76a and 76b of the robot hand 7 according to the present embodiment is not limited to this. 17 to 22 are diagrams respectively showing first to sixth modified examples of the robot hand 7 according to the present embodiment. As long as the grip function, the tray function, and the shooter function can be realized, the shape and arrangement of the pair of fingers 76a and 76b can be appropriately changed according to the shape and size of the workpiece 200 to be grasped. .

  As shown in FIG. 17, each of the fingers 76 a and 76 b may have a shape of a half cylinder in which a rectangular cylinder is vertically split. The upper plate 763a and the lower plate 762a have the same width, and the upper plate 763b and the lower plate 762b have the same width.

  As shown in FIG. 18, the pair of fingers 76a and 76b may exclude the lower plates 762a and 762b and form a long body having an L-shaped cross section.

  The pair of fingers may not be configured in the same shape. As shown in FIG. 19, the finger 76a includes two plates 761a and 763a connected at right angles to each other, and the finger 76b has a lower plate 762b and an upper plate 763b connected in parallel by a side plate 761b. It becomes. The cross section of the finger 76a represents an L shape, and the cross section of the finger 76b represents a U shape.

  The pair of fingers may not be linear. As shown in FIG. 20, the pair of fingers 76a and 76b may be tapered so as to gradually spread from the root side toward the tip side.

  The pair of fingers may not be arranged in parallel. As shown in FIG. 21, the pair of fingers 76a and 76b may be slightly inclined toward the inside. As shown in FIG. 22, the pair of fingers 76a and 76b may be slightly inclined toward each other.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  7 ... Robot hand, 71 ... Adapter plate, 72 ... Base, 73 ... Tube hole, 74 ... Rail, 76a, 76b ... Finger, 761a, 761b ... Side plate, 762a, 762b ... Lower plate, 763a, 763b ... Upper plate, 77a , 77b ... Pad.

Claims (7)

  It is provided with a pair of fingers supported by the base so as to be movable in the direction of approaching / separating from each other, each of the fingers has a long section with a concave section or an L section, and a pad is mounted on the inner surface thereof. Characteristic robot hand.   2. The robot hand according to claim 1, wherein the pair of fingers are arranged in parallel so that their inner surfaces face each other.   2. The robot hand according to claim 1, wherein the pad is arranged on a base side of the finger.   The robot hand according to claim 1, wherein the pad is thinner than a depth of the finger.   2. The robot hand according to claim 1, wherein the pad is an elastic body.   The robot hand according to claim 1, wherein the pad is a bag body that can be expanded and contracted.   2. The robot hand according to claim 1, wherein an adapter plate for connecting to the robot arm is provided on the base portion in parallel with the pair of fingers.

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