JP2019093512A - Fingertip mechanism and robot hand incorporating fingertip mechanism - Google Patents

Abstract

To provide a fingertip mechanism improved in disadvantage while taking advantage of a familiar mechanism of a fingertip portion, and a robot hand incorporating the mechanism.SOLUTION: If it is configured so as to limit rotation by a familiar mechanism of a fingertip portion 5, a fingertip mechanism can lift and move an object in a stable state since a straight portion of a bar member is gripped from left and right by the finger tip portion 5 as shown in Fig. 4.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a fingertip mechanism that contacts an object when the robot grips an object, and a robot hand incorporating this mechanism.

  The mechanisms disclosed in Patent Document 1 to Patent Document 3 are known as robot hands that hold objects with a plurality of fingertips.

  Patent Document 1 discloses a robot hand having three finger portions, and the fingertip portion at the tip of each finger portion is rotated by a predetermined angle by driving an actuator provided in the finger base, and further the finger portion is A protrusion is provided at the tip, and a protrusion different from the protrusion is provided on the back side of the fingertip, and when grasping a large object, it is gripped by the fingertips of three fingers and small When pinching like a tweezer, it is made to hold between two projection parts.

  Patent Document 2 also discloses a robot hand including three robot finger units, each robot finger unit includes a first member, a second member, an intermediate member, two axles, and two pulleys. And a rotary tension adjusting member and a fixing member, and driven by a driving member provided in each robot finger unit.

  Patent Document 3 (FIG. 11) discloses a robot finger including a base end member, an intermediate member, and a tip member as movable members with respect to a fixed member, and the tip member includes a guide groove (long hole) and a coil spring. A copying mechanism is provided, and when the pressing force acts on the tip end member in the direction opposite to the turning direction to the bending state, the tip moving member rotates around the second hinge portion by the copying mechanism. By setting it, it is set as the structure which performs relaxation operation, when a tip member contacts a work, when a tip member collides, etc.

  In all of Patent Documents 1 to 3, the fingertip portion is rotatable with respect to the base, but it does not rotate freely according to the surface shape of the object to be grasped, and the rotation is performed by a link mechanism or a wire. The motion angle is completely controlled. Such a structure may reduce the contact area between the object to be grasped and the fingertip of the robot, and the grasp may become unstable. In order to solve this, it is also conceivable to adopt a familiar mechanism in which part of the fingertip portion in contact with the object to be gripped is free (including a structure in which the spring returns to the neutral position).

JP, 2015-229199, A JP, 2011-121162, A WO 2008/026574

  FIG. 5A shows a state in which the object to be grasped is gripped by a conventional robot finger not equipped with a familiar mechanism, and in this case, the object to be grasped and the tip of the robot finger are close to point contact. , Gripping becomes unstable.

  FIG. 5 (b) shows a state in which the object to be grasped is gripped by a conventional robot finger provided with a familiar mechanism, and the contact portion between the tip of the rotatable finger and the object to be grasped is If the contact portion is located earlier than the pivoting center of the tip of the finger if it is slightly above the tapered portion of the object to be grasped, the tip of the finger is pivoted and the tip of the finger is The tapered portion of the object to be grasped is grasped, and in this state, the grasping state becomes extremely unstable, and the object to be grasped can not be lifted or moved.

10 to 14 of Patent Document 3 disclose a copying mechanism consisting of an elongated hole shaped guide groove and a coil spring in a robot finger. In this copying mechanism, the robot finger moves further to the extension side and the coil spring acts on the extension side when the stopper at the end of the guide groove is in a gripping state at a position where the stopper does not work. The work can not be fixed. In addition, when gripping by the copying mechanism, it is described that the reaction force from the work does not act excessively, and that it absorbs the pressing force, and the reaction force is reduced because the work is gripped and fixed. The absorption of pressure and pressure results in a state of "warming and pushing arms", and sufficient gripping characteristics can not be obtained.
Further, in the case of the above copying mechanism, once the guide groove is formed, the applicable workpiece shape is determined by the copying mechanism, and it is impossible to track the change in workpiece shape.

  Therefore, when the tip is rotated along the surface shape of the object to be grasped and the contact area is increased while gripping one object by the joint work with another robot finger, the object can not be gripped due to excessive rotation. A fingertip mechanism that prevents that is desired.

  In order to solve the above-described problems, in the fingertip mechanism according to the present invention, the fingertip portion in contact with the object to be grasped of the finger unit consisting of a plurality of parts connected to each other is pivotable in accordance with the shape of the object to be grasped The rotation range of the fingertip to the outside is restricted by the stopper member.

As said stopper member, the plate-shaped stopper etc. which are arrange | positioned via a clearance gap on the outer side of a fingertip part can be considered.

The robot hand according to the present invention has a configuration in which a plurality of finger units are provided, and the fingertip mechanism is incorporated in the fingertip portion of the tip of each finger unit.

  As an application example of the robot hand, in addition to a five-fingered humanoid hand, it may be provided with a plurality of finger units such as two fingers and three fingers.

  According to the fingertip mechanism according to the present invention, while maintaining the advantage of the familiar mechanism, ie, the advantage of increasing the contact area between the object to be grasped and the fingertip of the robot, the disadvantage of the familiar mechanism, ie, the contact portion with the object to be grasped Depending on the shape, it is possible to eliminate the disadvantage that the familiar mechanism is turned more than necessary and can not be gripped.

  As a result, the degree of freedom of the shape of the object which can be grasped increases, and when it is applied to the robot hand, even when the shape of the object to be grasped changes halfway, the work is continued without replacing the tip of the finger unit. The working efficiency of the plant's hybrid line etc. can be improved.

  Further, according to the fingertip mechanism according to the present invention, when the shape of the workpiece to be grasped is changed, it is easy to replace the stopper member with a stopper member of another shape and adjust the distance from the fingertip portion. Can handle many types of work.

The figure which shows the state which hold | gripped the big object by the finger unit provided with the finger tip mechanism which concerns on this invention Figure showing the same finger unit holding a small object Enlarged view of the tip of the finger unit An enlarged view showing a state in which a tapered part is gripped by the tips of a pair of finger units (A) is a figure which showed the state which grasped the to-be-held object by the conventional robot finger which is not equipped with a familiar mechanism, (b) shows the state which grasped an object to be grasped with the conventional robot finger equipped with a familiar mechanism Figure

  As shown in FIGS. 1 to 3, the robot hand R includes a plurality of (two or three) finger units 1. The illustrated example shows a pair of left and right finger units 1. The finger unit 1 includes a base 2, an intermediate portion 3, a tip 4 and a fingertip 5 attached to the tip 4.

  The base 2 is a base frame 22 whose proximal end is rotatably connected to the distal end of the robot hand R via a shaft 21, and a first link 23 whose proximal end is also rotatably connected to the shaft 21. The distal end of the first link 23 includes a second link 25 rotatably connected at its proximal end via a shaft 24.

  The middle part 3 includes a middle part frame 32 whose middle part is rotatably connected to the distal end of the second link 25 via a shaft 31, and the base end part of the middle part frame 32 is connected via a shaft 33. The distal end portion of the base frame 22 is pivotably connected, and the distal end portion of the intermediate frame 32 is pivotably connected via a shaft 34.

  The tip 4 comprises an actuator 41 and a driven part 42. The actuator 41 is rotatably connected to the base end of the intermediate frame 32 via the shaft 34 as described above, and the driven part 42 is an actuator. It rotates around the shaft 43 by 41.

  The proximal end of the third link 35 is rotatably connected to the distal end of the base frame 22 via the shaft 26, and the distal end of the third link 35 is the actuator 44 via the shaft 44. 41 are linked.

  In the above, the left and right finger units 1 are opened, that is, the right finger unit 1 is inclined to the right of the illustrated state in FIG. 1, and the left finger unit 1 is inclined to the left than the illustrated state. As a starting point.

  From the above state, the power from the drive unit is transmitted to the first link 23 by a wire or a link member (not shown). That is, for the finger unit 1 on the right side in the figure, the first link 23 is pivoted counterclockwise around the shaft 21, and for the finger unit 1 on the left side, the first link 23 clockwise about the shaft 21. Rotate.

  Then, the second link member 25 moves upward, and in the finger unit 1 on the right side, the middle frame 32 rotates counterclockwise around the shaft 33, and in the finger unit 1 on the left side, the shaft 33 The intermediate portion frame 32 pivots clockwise about the center of the circle.

  When the middle portion frame 32 pivots around the shaft 33, the actuator portions 41 of the finger units 1 on the left and right sides move inward. Here, since the actuator portion 41 and the base frame 22 are connected via the third link 35, the actuator portion 41 is also pivoted inward in conjunction with the inward pivoting of the intermediate portion frame 32, further The driven portion 42 and the fingertip portion 5 extending from the actuator portion 41 also rotate inward, and the state of FIG. 1 in which the object to be grasped W is wrapped by the left and right finger units 1 is obtained.

  Next, the structure of the fingertip portion 5 will be described. The fingertip portion 5 is rotatably connected to the driven portion 42 via a shaft 45. Since the fingertip portion 5 is a portion directly in contact with the surface of the object to be grasped W, it is preferable that the contact surface be made of a material such as urethane resin which does not scratch the surface of the object to be grasped W.

  The finger tip portion 5 is rotatably supported via a shaft 45, but by providing a spring 51 around the shaft 45, the finger tip portion 5 is structured to stop at an initial position (the state of FIG. 3). When the object to be grasped W is gripped in this state, the finger operation unit 5 is rotated against the spring 51 in accordance with the outer shape of the object to be grasped W, so that a familiar mechanism is adopted.

Further, the inner shape of the fingertip portion 5 is set to a shape in which the contact portion P with the object to be held W is on the inner side and the front side of the shaft 45. Therefore, in the case where the shape of the object to be grasped W is special, it is necessary to have an inner shape that matches the shape.

  Furthermore, a stopper member 52 is provided on the outside of the stopped fingertip portion 5 with a gap. The stopper member 52 is for limiting the amount of rotation by the familiar mechanism in which the fingertip portion 5 is rotated according to the shape of the object W to be grasped when the object W is gripped by the fingertip 5 The shape does not have to be plate-like, and the place to be formed may not be outside the fingertip portion 5.

  In the above, assuming that the rod member having a tapered lower portion is assumed as the shape of the object to be grasped W, the fingertip portion 5 is initially formed as shown in FIG. Although the finger is in contact with the linear portion of the rod member, the finger tip portion is rotated by the familiar mechanism and the finger tip portion 5 is in contact with the tapered portion. Since this state is extremely unstable, the object to be grasped W can not be moved or lifted.

  On the other hand, when restriction is given to the rotation of the fingertip portion 5 by the familiar mechanism as in the present invention, as shown in FIG. 4, a straight line adjacent to the tapered portion of the grasped object W having a straight portion and a tapered portion. When gripping the portion with the fingertip portion 5, the fingertip portion 5 does not rotate following the tapered portion even if a part of the fingertip portion 5 is placed on the tapered portion, and firmly holds the linear portion.

  As described above, the fingertip mechanism according to the present invention can maintain the gripping state even when the fingertip portion 5 contacts the boundary portion between the tapered portion and the linear portion of the object to be grasped W having the tapered portion and the linear portion. .

  There are many members whose end is tapered as the object to be grasped W. In such a case, according to the present invention, it is possible to design that the immediate vicinity of the tapered portion can be gripped by the fingertip 5, but in the case of only the conventional familiar mechanism, the portion near the tapered portion is gripped You must avoid doing. Therefore, in the case of the present invention, the degree of freedom in robot design is increased.

  In the embodiment, an example is shown in which the inner shape of the fingertip 5 is designed such that the contact portion P with the object to be grasped W is on the inner side and the front side of the rotation axis 45 of the fingertip. When it is designed to turn back 5 to the driven portion 42 side, it is also conceivable that the contact portion P with the object to be held W is on the rear side of the rotating shaft 45.

  The fingertip mechanism according to the present invention can be used for industrial use such as a humanoid hand or as an artificial hand.

  DESCRIPTION OF SYMBOLS 1 ... finger unit, 2 ... base, 21 ... axis, 22 ... base frame, 23 ... 1st link, 24 ... axis, 25 ... 2nd link, 3 ... middle part, 31 ... axis, 32 ... middle part frame, 33 ... Axis 34 34 axis 35 Third link 4 Tip 41 Actuator part 42 Driven part 43 Axis 44 Axis 54 Finger part 51 Spring 52 Stopper member R: robot hand, W: object to be held, P: contact portion.

Claims (3)

A fingertip mechanism that constitutes a finger unit of a robot hand,
The finger unit is composed of a plurality of parts connected to each other, and among the plurality of parts, a finger tip portion contacting the object to be grasped is rotatable according to the shape of the object to be grasped, and the tip of the finger tip portion is outside A finger tip mechanism characterized in that the rotation beyond a certain extent is restricted by a stopper member.   The fingertip mechanism according to claim 1, wherein the stopper is a plate-like stopper disposed outside the fingertip portion with a gap. A robot hand comprising a plurality of finger units, wherein the robot hand incorporates the fingertip mechanism according to claim 1 into the fingertip of the tip of each finger unit.

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