JP2011115914A - Robot hand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a robot hand capable of improving rotation accuracy of a gripping object gripped by a gripping part, and capable of increased even its rotation quantity. <P>SOLUTION: This robot hand 1 is rotated by gripping the gripping object. The robot hand includes a pair of gripping parts 11 and 12 for performing opening/closing operation in parallel for sandwiching and gripping the gripping object, and a moving means for moving at least one gripping part in the vertical direction to a rotary shaft O of the gripping object so as to dislocate a relative position of the mutual gripping parts in a state of gripping the gripping object. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a robot hand, and more particularly to a robot hand that rotates a gripping target such as a workpiece.

  Conventionally, a robot hand that grips a gripping target such as a workpiece has been used. For example, by providing a robot hand at the tip of the robot arm, the robot can grasp and move the object to be grasped. In such a robot hand, in addition to gripping the grip target, an operation for rotating the grip target may be required.

  Therefore, for example, Patent Document 1 discloses a technique for rotating a gripping object by rotating a pair of gripping parts that sandwich and grip the gripping object in directions opposite to each other in a direction perpendicular to the gripping part. Further, for example, Patent Document 2 discloses a technique for rotating a gripping object by adjusting the positional relationship between three fingers that grip the gripping object.

JP-A 64-27874 JP-A-6-155358

  However, in the technique disclosed in Patent Document 1, since the gripping portion performs a rotation operation, the amount of movement of the gripping portion differs between the root and the tip of the gripping portion. Therefore, there is a problem that slip is likely to occur between the grip portion and the grip target, and it is difficult to control the rotation amount with high accuracy. Further, the technique disclosed in Patent Document 2 has a problem that it is difficult to increase the amount of rotation of the gripping object only by moving the finger.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a robot hand that can improve the rotation accuracy of a gripping object gripped by a gripping portion and can increase the rotation amount. And

  In order to solve the above-described problems and achieve the object, the present invention is a robot hand that grips and rotates a gripping target, and includes a pair of gripping units that open and close in parallel to sandwich and grip the gripping target. A moving means for moving at least one gripping part in a direction perpendicular to the rotation axis of the gripping target so as to shift the relative positions of the gripping parts in a state where the gripping target is gripped. To do.

  According to the present invention, since the gripping part moves in a direction perpendicular to the rotation axis of the gripping object, it is possible to prevent slipping between the gripping part and the gripping object in the process of rotating the gripping target. There is an effect that the rotation accuracy of the object can be improved. In addition, since the gripping object is rotated by the movement of the gripping part in the direction perpendicular to the rotation axis of the gripping object, the rotation amount can be increased. For example, if the length of the gripping portion in the moving direction is equal to or greater than the outer peripheral length of the gripping target in the rotation direction, the gripping target can be rotated 360 degrees or more by moving the gripping portion.

FIG. 1 is an external front view showing a schematic configuration of a robot hand according to Embodiment 1 of the present invention. FIG. 2 is a diagram illustrating a schematic configuration of a moving mechanism provided in the housing. 3A and 3B are diagrams illustrating a state where the gripping target is gripped by the gripping unit, in which FIG. 3A is a diagram illustrating a state where the advancing and retreating positions of the gripping unit are substantially equal, and FIG. It is a figure which shows the state which moved to the direction and rotated the grip object, (c) It is a figure which shows the state which moved the grip part to the advancing direction and moved the grip part to the evacuation direction, and rotated the grip object. 4A and 4B are external front views of the robot hand, in which FIG. 4A is a diagram illustrating a state in which a gripping target having a square cross section is gripped, and FIG. 4B is a diagram illustrating a state in which the gripping target having a quadrangular cross section is rotated. FIG. 5 is a diagram illustrating a state where the robot hand according to the first embodiment is attached to the arm of the robot. FIGS. 6A and 6B are external front views of the robot hand according to the first modification of the first embodiment, in which FIG. 6A shows a state in which the gripping target is gripped, and FIG. 6B and FIG. 6C rotate the gripping target. It is a figure which shows a state.

  Embodiments of a robot hand according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is an external front view showing a schematic configuration of a robot hand according to Embodiment 1 of the present invention. The robot hand 1 is a device for gripping a gripping target such as a workpiece. The robot hand 1 has a pair of grip portions 11 and 12. The gripping portions 11 and 12 can move in parallel with the direction indicated by the arrow X, and can be opened and closed. By closing the gripping portions 11 and 12, the gripping target can be sandwiched and gripped. Anti-slip treatment is applied to the opposing surfaces 11a and 12a of the grip portions 11 and 12 so that the grip target can be securely gripped. For example, the opposing surfaces 11a and 12a may be made of a rubber member. Further, the opposing surfaces 11a and 12a may be roughened to increase the frictional resistance. The gripping portions 11 and 12 can be moved linearly in a direction perpendicular to the opening / closing direction (direction indicated by an arrow Y). Hereinafter, the movement of the gripping portions 11 and 12 in the direction indicated by the arrow X is referred to as movement in the opening / closing direction, and the movement of the gripping portions 11 and 12 in the direction indicated by the arrow Y is referred to as movement in the forward / backward direction. Further, regarding the movement of the gripping portions 11 and 12 in the forward / backward direction, the direction away from the housing 2 is referred to as the movement in the advance direction, and the direction approaching the housing 2 is referred to as the movement in the retreat direction.

  The grips 11 and 12 are moved by a moving mechanism (moving means) 4 provided inside the housing 2. FIG. 2 is a diagram showing a schematic configuration of the moving mechanism 4 provided inside the housing. First, a mechanism for opening and closing the grip portions 11 and 12 will be described.

  Advancing and retracting guide rails 133 and 134 extending toward the inside of the housing 2 are attached to the gripping portions 11 and 12 on the base side. The advance / retreat guide rails 133, 134 pass through openings 131a, 132a formed in the advance / retreat guide blocks 131, 132 on the way. The open / close guide blocks 31 and 32 formed integrally with the advance / retreat guide blocks 131 and 132 are slidable on the open / close guide rail 30. Thereby, the advancing / retreating guide rails 133, 134 and the gripping portions 11, 12 move in the opening / closing direction in accordance with the movement of the opening / closing guide blocks 31, 32 in the opening / closing direction.

  The open / close guide blocks 31 and 32 are connected to the belt 43. The belt 43 is hung between pulleys 41 and 42 disposed outside the opening / closing guide blocks 31 and 32 in the opening / closing direction, and the belt 43 also rotates in accordance with the rotation of the pulleys 41 and 42. . Of the opening / closing guide blocks 31, 32, one opening / closing guide block 31 is connected to a belt 43 portion that passes through one side of the pulleys 41, 42, and the other opening / closing guide block 32 is connected to the pulley 41. , 42 is connected to a belt 43 portion passing through the other side. The pulley 41 is connected to the rotating shaft portion 21a of the opening / closing motor 21, and the pulley 41 also rotates in accordance with the rotation of the rotating shaft portion 21a.

  With the above configuration, when the rotating shaft 21 a of the opening / closing motor 21 is rotated to rotate the pulley 41, the gripping portions 11, 12 are opened and closed in accordance with the rotation of the belt 43. Specifically, when the pulley 41 is rotated in the direction indicated by the arrow P, the gripping portions 11 and 12 move so as to open, and when the pulley 41 is rotated in the direction indicated by the arrow Q, the gripping portions 11 and 12 are closed. Moving.

  A constant pressure control unit 24 is connected to the opening / closing motor 21. The constant pressure control unit 24 functions as a constant pressure control unit that controls the opening / closing motor 21 so that the gripping pressure at which the gripping units 11 and 12 grip the gripping object becomes substantially constant. The constant pressure control unit 24 performs current control on the opening / closing motor 21 based on the gripping pressure detected by a pressure detection unit (not shown), and makes the gripping pressure constant.

  Next, a mechanism for moving the grip portions 11 and 12 forward and backward will be described. Racks 51 and 52 are provided on the other end side where the gripping portions 11 and 12 of the advance / retreat guide rails 133 and 134 are provided. Pinion gears 61 and 62 are meshed with the racks 51 and 52, respectively. Thereby, the advancing / retreating guide rails 133, 134 and the gripping portions 11, 12 can linearly move in the advancing / retreating direction in accordance with the rotation of the pinion gears 61, 62. The linear movement of the advance / retreat guide rails 133, 134 and the gripping portions 11, 12 in the advance / retreat direction is defined by the advance / retreat guide blocks 131, 132.

The pinion gears 61 and 62 rotate in conjunction with the pulleys 45 and 46, respectively. A belt 47 is hung between the pulley 44 connected to the rotation shaft portion 22 a of the advance / retreat motor 22 and the pulley 45, and the pulley 45 rotates in accordance with the rotation of the pulley 44. Similarly, the pulley 46 also has a belt 48 hung between the pulley 44 connected to the rotating shaft portion 22 a of the advance / retreat motor 22, and the pulley 46 rotates in accordance with the rotation of the pulley 44.
The pulley 44 has a shape in which the pulleys are stacked in two stages so that both the belt 47 and the belt 48 can be hung.

  With the above configuration, when the pulley 44 is rotated by rotating the rotary shaft portion 22 a of the advance / retreat motor 22, the gripping portions 11, 12 move forward / backward in accordance with the rotation of the pulleys 45, 46. Specifically, when the pulley 44 is rotated in the direction indicated by the arrow R, the grip portion 11 moves in the retracting direction, and the grip portion 12 moves in the advance direction. Further, when the pulley 44 is rotated in the direction indicated by the arrow S, the grip portion 11 moves in the advance direction, and the grip portion 12 moves in the retreat direction. That is, by rotating the pulley 44, the gripping portions 11 and 12 can be translated in opposite directions to shift the relative positions of each other.

  Further, the movement amounts of the gripping part 11 and the gripping part 12 in the advancing and retreating directions are substantially equal. Specifically, the gear ratios of the racks 51 and 52 and the pinion gears 61 and 62 are made equal on the gripping part 11 side and the gripping part 12 side, and the sizes of the pulleys 45 and 46 are set to the gripping part 11 side and the gripping part 12. The amount of movement of the gripping part 11 and the gripping part 12 in the advancing / retreating direction is made substantially equal by making them equal on the side.

  The moving mechanism 4 has a biasing means 6 that applies a biasing force to the pulley 44 in the direction indicated by the arrow U. The biasing means 6 is, for example, a coil spring. By applying an urging force to the pulley 44 by the urging means 6, even when the pulleys 45 and 46 are moved by the opening / closing operation of the gripping portions 11 and 12, the distance between the pulley 44 and the pulley 45, the pulley 44 and the pulley 44 The pulley 44 can be moved so as to maintain a constant distance from the pulley 46, and the rotation of the pulley 44 can be reliably transmitted to the pulleys 45 and 46. Of course, the advancing / retracting motor 22 is also movably provided in accordance with the movement of the pulley 44.

  Next, rotation of the object to be grasped by the robot hand 1 will be described. FIGS. 3A and 3B are diagrams showing a state in which the gripping object is gripped by the gripping portions 11 and 12, where FIG. 3A is a diagram illustrating a state in which the advancing and retreating positions of the gripping portions 11 and 12 are substantially equal, and FIG. The figure which shows the state which moved the holding part 12 to the advancing direction in the direction, and rotated the holding object, (c) The holding part 11 was moved to the advancing direction, the holding part 12 was moved to the retreating direction, and the holding object was rotated. FIG.

  As shown in FIG. 3, the gripping units 11 and 12 translate in the opposite direction with the same amount of movement, so that the gripping target can be rotated with little movement of the rotation axis O of the gripping target. In addition, since the gripping units 11 and 12 move in a direction perpendicular to the rotation axis O of the gripping target, it is difficult to cause slippage between the gripping units 11 and 12 and the gripping target in the process of rotating the gripping target. it can. Thereby, the rotation accuracy of the object to be grasped can be improved.

  Further, since the gripping object is rotated by the movement of the gripping portions 11 and 12 in the direction perpendicular to the rotation axis O of the gripping object, the amount of rotation can be increased. For example, if the length of the facing surfaces 11a, 12a in the advance / retreat direction is equal to or greater than the outer peripheral length of the grip target, the grip target can be rotated 360 degrees or more by the forward / backward movement of the grip portions 11, 12.

  4A and 4B are external front views of the robot hand 1, wherein FIG. 4A is a diagram illustrating a state in which a gripping target having a square cross section is gripped, and FIG. 4B is a diagram illustrating a state in which the gripping target having a quadrangular cross section is rotated. As shown in FIG. 4, when the object to be grasped having a quadrangular cross section is rotated, the opening / closing interval of the grasping portions 11 and 12 changes in the course of the rotation. Since the moving mechanism 4 of the robot hand 1 includes the constant pressure control unit 24 that makes the gripping pressure substantially constant, even when the opening / closing width of the gripping units 11 and 12 changes due to rotation, the gripping pressure is substantially constant. Thus, the object to be grasped can be grasped stably. The cross-sectional shape of the quadrangular cross section is an example of a cross-sectional shape in which the opening / closing width of the gripping portions 11 and 12 is changed by rotation, and the cross-sectional shape of the gripping target is not limited thereto.

  FIG. 5 is a diagram illustrating a state where the robot hand 1 according to the first embodiment is attached to the arm of the robot 10. The arm of the robot 10 has one or a plurality of movable axes, and moves a gripping target such as a workpiece to a predetermined position in a predetermined posture. Conventionally, when there is a request to suppress the movement of the rotation axis when rotating the gripping target, it is necessary to provide the robot arm with many movable axes, which may increase the cost of the robot. there were. On the other hand, by attaching the robot hand 1 to the arm of the robot 10, the object to be grasped can be rotated without rotating the movable axis of the arm. That is, by attaching the robot hand 1 to the arm of the robot 10, the object to be grasped can be rotated while suppressing the movement of the rotation axis without relying on the movable axis of the arm. Thereby, the number of movable axes that the arm of the robot 10 should have can be suppressed, and an increase in the cost of the robot 10 can be suppressed.

  It should be noted that the moving mechanism 4 is configured by omitting one of the “pulley 45, belt 47, pinion gear 61” or “pulley 46, belt 48, pinion gear 62” from the moving mechanism 4 shown in FIG. Also good. In this case, when rotating the gripping object, only one gripping part moves forwards and backwards, so it is difficult to suppress the movement of the rotation axis of the gripping object, but the sliding accuracy between the gripping part and the gripping object is suppressed and the rotation accuracy is improved. Can be achieved. In addition, the amount of rotation of the gripping target can be increased.

  Note that the moving mechanism for causing the gripping portions 11 and 12 to open / close and advance / retreat is not limited to the configuration shown in FIG. That is, the configuration of the moving mechanism 4 includes opening / closing movements of the gripping units 11 and 12 for gripping the gripping target, and forward / backward movement for shifting the relative positional relationship of the gripping units 11 and 12 to rotate the gripping target. Any configuration that can be realized is acceptable. For example, in the first embodiment, both the gripping portions 11 and 12 are moved to open and close by a single opening / closing motor 21, but driving means such as a motor for moving the gripping portions 11 and 12 to open and close is provided. You may comprise so that the opening / closing movement of the holding parts 11 and 12 may be controlled separately. In addition, although both the gripping portions 11 and 12 are moved forward and backward by a single advancing / retreating motor 22, driving means such as a motor for moving the gripping portions 11 and 12 forward / backward is provided to move the gripping portions 11 and 12 forward / backward. You may comprise so that a movement may be controlled separately.

  6A and 6B are external front views of the robot hand 1 according to the first modification of the first embodiment, in which FIG. 6A shows a state in which the gripping target is gripped, and FIG. 6B and FIG. 6C rotate the gripping target. FIG. In the first modification, recesses 11b and 12b are formed on the opposing surfaces 11a and 12a of the gripping portions 11 and 12, respectively. By forming the recessed portions 11b and 12b on the opposing surfaces 11a and 12a, it becomes possible to stably hold the object to be gripped. Moreover, when the recessed parts 11b and 12b are formed in the opposing surfaces 11a and 12a, the opening and closing widths of the gripping parts 11 and 12 change when the gripping target is rotated. As described above, by providing the constant pressure control unit 24, even when the opening / closing width of the gripping units 11 and 12 changes, the gripping target can be stably gripped with a substantially constant gripping pressure. Moreover, when the gripping target is rotated among the recesses 11b and 12b, the contact surfaces that are in contact with the gripping target are made parallel to each other, so that the movement of the rotation axis of the gripping target can be suppressed. In addition, you may form the dent parts 11b and 12b in various shapes according to the shape of a holding object.

  As described above, the robot hand according to the present invention is useful for a robot arm, and is particularly suitable for a robot arm that rotates a gripping target such as a workpiece.

1 Robot hand 2 Housing 4 Moving mechanism (moving means)
6 Energizing means 10 Robot 11, 12 Grasping part 11a, 12a Opposing surfaces 11b, 12b Recessed part 21 Opening / closing motor 21a Rotating shaft part 22 Advancing / retreating motor 22a Rotating shaft part 24 Constant pressure control part (constant pressure control means)
30 Opening and closing guide rails 31 and 32 Opening and closing guide blocks 41 and 42 Pulley 43 Belts 44, 45 and 46 Pulleys 47 and 48 Belts 51 and 52 Racks 61 and 62 Pinion gears 131 and 132 Advancing and retreating guide blocks 131a and 132a Opening 133 134 Guide rail for advancing / retreating O Rotating shaft P, Q, R, S, U, X, Y Arrow

Claims (5)

A robot hand that grips and rotates a gripping object,
A pair of gripping parts that open and close in parallel to sandwich and grip the gripping object;
Moving means for moving at least one gripping part in a direction perpendicular to the rotation axis of the gripping object so as to shift the relative positions of the gripping parts in a state where the gripping target is gripped. Characteristic robot hand.   2. The robot hand according to claim 1, wherein the moving unit moves both of the pair of gripping portions in substantially opposite amounts in the opposite directions.   3. The robot hand according to claim 1, further comprising a constant pressure unit configured to hold a pressure at which the pair of gripping units sandwich the gripping object substantially constant. 4.   The robot hand according to any one of claims 1 to 3, wherein a concave portion is formed on opposing surfaces of the gripping portions.   The robot hand according to any one of claims 1 to 4, wherein an anti-slip process is performed on opposing surfaces of the gripping portions.

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