JP2511164B2 - Coupling for position correction of robot hand - Google Patents

Description

Description: TECHNICAL FIELD The present invention is provided between a robot hand that grips a work and a robot arm, and the relative position between the work gripped by the robot hand and a mating member into which the work is incorporated. Even if the position is deviated, the position correction coupling of the robot hand (hereinafter, simply referred to as "coupling") for accurately assembling the work into the partner member while correcting the position of the work according to the position of the partner member. ) Concerning.

2. Description of the Related Art Conventional Art and Its Problems Conventionally, when performing assembly work for inserting a shaft (workpiece) into a hole of a bracket (a mating member) using a robot, if the relative position between the hole and the shaft is misaligned,
The shaft cannot be inserted into the hole as it is.
Therefore, as shown in FIG. 14, the coupling 21 composed of the elastic bodies 20, 20 is attached to the robot arm 22 and the robot hand.
The position is adjusted to 23 so that the position can be corrected by the amount of the deviation. The robot hand 23 uses the deformation of the elastic bodies 20, 20 to move laterally along with the shaft S that slides on the conical surface C at the entrance of the hole B as the robot arm 22 descends. Can be inserted into.

However, since such a coupling 21 is too soft as a whole, the robot hand 23 performs a combined movement of movement in the X, Y, and Z axis directions and rotation about each of these axes. (6 degrees of freedom), as shown in FIG. 15, the posture of the shaft S sliding on the conical surface C cannot be held constant, and the shaft S may not be inserted into the hole B in some cases. have.

Means for Solving the Problems According to the present invention, a first rotating body rotatably provided on a robot arm, and a first rotating body rotatably around a first rotation tilt axis oblique to the first rotating body. A second rotating body mounted on the body and a robot hand mounted on the second rotating body so as to be rotatable around a second rotating tilt axis parallel to the first rotating tilt axis and parallel to the robot arm. The third rotation body having a surface is provided between the first rotation tilt axis and the second rotation tilt axis, and the rotation of the one rotation tilt axis causes the other rotation tilt axis to move in the same direction. A gear train to rotate, the robot arm and the first
A first elastic body provided between the rotary body, a second elastic body provided between the first rotary body and the first rotation tilt axis, the second rotation tilt axis and the third The above problem is solved by a coupling for correcting the position of the robot hand, which has a third elastic body provided between the rotary body and the rotary body.

Action When the relative positions of the work held by the hand and the hole match, the work is inserted into the hole without contacting the conical surface formed at the entrance of the hole, so no force is applied to the work. Does not work. Therefore, each rotating body remains stationary.

When the relative positions of the work and the hole are deviated from each other, the work comes into contact with the conical surface at the entrance of the hole as the robot arm descends, receives a lateral force and an axially upward force, and undergoes a third rotation. The two forces are applied to the body. Then, the force causes at least one of the three rotating bodies to rotate. Further, due to the rotation of the rotating body, at least one elastic body among the first, second and third elastic bodies is twisted.

That is, due to the lateral and axial forces as described above,
When the third rotating body rotates, the third rotating body rotates about the oblique second rotation tilt axis. When the second rotating body rotates,
The first rotation tilt axis is rotated so as to escape obliquely upward. Further, when the first rotating body rotates due to the lateral force, it rotates parallel to the robot arm. Such rotation of each rotating body allows movement of the work according to the position and shape of the hole, so that the work can be inserted into the hole.

The coupling after the work is inserted into the hole returns to the original state by the elastic energy accumulated in the twisted elastic body, and returns the robot hand to the original position.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

The robot hand position correcting coupling (hereinafter, simply referred to as “coupling”) 31 has a support 32 made of a rigid body, and first, second and third rotating bodies 33, 34, 35. .
The support 32, the first, second and third rotating bodies 33, 34 and 35 are rotatably connected to each other by the first, second and third bearing mechanisms 36, 37 and 38. The lower surface 40 of the first rotating body 33 and the third rotating body 35
The upper surfaces 41 of the two are inclined surfaces parallel to each other. Therefore,
The second rotating body 34 is obliquely provided between the inclined surfaces.

The hand mounting surface 42, which is the lower surface of the third rotating body 35 to which the robot hand 30 is mounted, is the lower surface of the robot arm 43 in FIG. 1 when the coupling 31 is not displaced at all.
It is formed to be parallel to 48.

Between the first rotating body 33 and the second rotating body 34, and between the second rotating body 34 and the third rotating body 35, the second and third rotating bodies which are perpendicular to the upper and lower surfaces of the second rotating body 34. First and second rotary tilt shafts 52, 53 penetrating the bearing members 50, 51 of the bearing mechanisms 37, 38 are provided in parallel with each other. Therefore, the first rotary tilt shaft 52 is inclined with respect to the first rotary body 33. Similarly, the second rotation tilt shaft 53 is inclined with respect to the third rotation body 35. Support 32
The left-handed spring 54 and the right-handed spring are provided between the first and second rotating bodies 33.
55 has a first portion between the first rotating body 33 and the first rotation tilt shaft 52.
Elastic disks 46 are provided, and second elastic disks 47 are provided between the second inclined shaft 53 and the third rotating body 35.

Between the first and second rotary tilt shafts 52, 53, the first, second,
A gear train 59 consisting of third gears 56, 57, 58 is provided.
The first gear 56 is provided on the first rotary tilt shaft 52, the second gear 57 is provided on the second rotary body 34, and the third gear 58 is provided on the second rotary tilt shaft 53. The number of teeth of the first gear 56 and the number of teeth of the third gear 58 are the same.

 Next, the operation will be described.

First, a case where the relative positions of the shaft S and the hole B match will be described.

The shaft S is directly above the hole B, and the robot arm 43
Even if the tool moves down, it is accurately assembled into the hole B without contacting the conical surface C of the hole B. Therefore, the coupling
No external force acts on the support 31, and as shown in FIG.
The second reference shaft 61 of the third rotating body 35 with respect to the first reference shaft 60 of
Are on a straight line. The first reference axis 60 is a positioning reference axis for the robot arm 43, and the second reference axis 61.
Is a central axis of the robot hand 30, both of which are imaginary axes for explaining the operation.

Next, a case where the relative positions of the shaft S and the hole B are deviated will be described with reference to the operation explanatory diagrams of FIGS. 6 to 11.

6 to 11, for convenience of explanation, the lower surface 40 of the first rotating body 33 and the upper surface 41 of the third rotating body 35 are made as close as possible to each other, assuming that the second rotating body 34 has no thickness. 2-2 in Fig. 1
FIG. 6 is a schematic cross-sectional view of a position corresponding to a cross-sectional view taken along the arrow, where the ◯ mark indicates the center position of the first rotation tilt shaft 52 (or the rotation center position of the second rotating body 34), and the Δ mark indicates the second rotation tilt shaft 53. Indicates the center position of (or the rotation center position of the third rotating body 35), and ● indicates the second reference axis.
The positions of 61 are shown respectively, and the second rotating body 34 is rotated to move the
It is also an exploded view of the locus, which shows three positions every 30 degrees. Further, the first rotating body 33 does not rotate. Further, the shaft S is accurately grasped by the robot hand 30, and the position of the hole B is displaced. Therefore, the centers of the second reference axis 61 and the shaft S coincide with each other.

Since the relative positions of the shaft S and the hole B are deviated, the shaft S cannot come directly above the hole B. For this reason,
The shaft S has a hole B as the robot arm 43 descends.
Contact the conical surface C formed at the entrance of the
₁ and a force F ₂ in the axial direction of the shaft S upward. Due to these two forces F ₁ and F ₂ , the third rotating body 35 rotates about the oblique second rotating tilt axis 61, and the second rotating body 34 escapes obliquely upward about the first rotating tilt axis 60. To rotate. This rotation is performed along with the movement of the shaft S along the conical surface C, and the rotation center of the third rotating body 35 and the second reference shaft 61 move from the position shown in FIG. 6 to the position shown in FIG. . The second rotating body 34 rotates counterclockwise, for example, 30 degrees with respect to the first rotating body 33, and the third rotating body 35 rotates the same angle (30 degrees) clockwise with respect to the second rotating body 34. Yes (holds the same phase). During this time, the first and second elastic disks 46, 47 connected by the gear train 59 are equally twisted in opposite directions, and elastic energy is stored. On the other hand, the hand mounting surface 42 of the third rotating body 35 moves obliquely upward (that is, as shown in FIG. 3 in which the second and third rotating bodies 34 and 35 have rotated 15 degrees, Y in the lateral direction, Only H will move in the height direction.).

Similarly, since the second and third rotating bodies 34 and 35 rotate in the same manner, the shaft S can be inserted into the hole B in a state of being aligned with the hole B. During this time, the first and second elastic disks 46, 47 are continuously twisted.

After the shaft S is inserted into the hole B, the robot hand 30
Since the shaft S is released, the external force does not act on each rotating body, and the elastic energy accumulated in the first and second elastic disks 46 and 47 causes the second and third rotating bodies 34 and 35 to move to the first position.
Returning to the original position shown in FIGS. 6 and 6, the robot arm 43 moves to get the next shaft S.

If the hole B is not on the locus of the second reference axis 61 shown in FIG. 11, the first rotating body 33 is also rotated and the shaft S is rotated.
Is inserted into hole B. At this time, right and left winding springs 54, 55
Is also twisted.

Further, when the hole B is inclined as shown in FIG. 12, the respective rotating bodies rotate without maintaining the same phase, whereby the second reference shaft 61 is relative to the first reference shaft 60. It becomes a crossed state. As a result, the third rotating body 35 can be tilted as shown by the angle α in FIG. 13 and the shaft S can be inserted into the oblique hole B. Such an oblique crossing state is the third rotating body.
It also occurs when only 35 rotates.

In addition, when the hole B is displaced to the opposite side with respect to the shaft S in FIG. 1, it is dealt with by rotating the first rotating body 33 by 180 degrees.

As described above, since the coupling 31 is composed of a combination of a rotating body made of a rigid body and an elastic body, it is possible to surely insert the shaft S into the hole B while keeping the shaft S always vertical. Not only can it be inserted, but it can also be inserted into an oblique hole. That is, of the 6 degrees of freedom, the resistance to movement in any of the X, Y, and Z axes is large, so that a coupling of substantially 5 degrees of freedom can be obtained.

Note that rubber is used for the elastic disk in the above embodiments.

EFFECTS OF THE INVENTION As described above, since the coupling of the present invention is configured by the combination of the elastic body and the rotating body made of a rigid body, the following effects can be obtained.

Since it has both rigidity and elasticity, the work can be reliably assembled into the mating member that is relatively displaced.

The coupling automatically moves according to the position and shape of the hole so that the reaction force becomes small, and it can be inserted not only in the vertical direction but also in an inclined hole, and it has excellent adaptability.

When the positions of the work and the mating member are deviated from each other, the second and third rotating bodies can move horizontally and ascend while rotating, so that the work moves to the mating member while the descending speed is reduced. As a result, the work can be smoothly incorporated into the mating member.

[Brief description of drawings]

FIG. 1 is a position correcting coupling of the present invention, and is a cross-sectional view taken along the first and second rotation tilt axes, FIG. 2 is a cross-sectional view taken along the line 2-2 in FIG. 1, and FIG. The second and third rotating bodies are 15
1 is a right side view when rotated by one degree, FIG. 4 is a bottom view of FIG. 3, and FIG. 5 is a schematic sectional view taken along the line 5-5 in FIG. Combined drawings, FIGS. 6 to 10 are operation explanatory views in a portion corresponding to FIG. 2, FIG. 11 is a locus view of the second reference shaft (shaft), and FIG. 12 has a diagonal hole. FIG. 13 is a state diagram when the shaft is inserted, and FIG. 13 is a state diagram when the shaft is inserted into the oblique hole and corresponds to FIG. And, FIG. 14 is a schematic front view of a conventional position correcting coupling, and FIG. 15 is an operation explanatory view thereof. 30 …… Robot hand 31 …… Coupling for position adjustment 33 …… First rotary body, 34 …… Second rotary body 35 …… Third rotary body 42 …… Robot hand mounting surface 43 …… Robot arm 46 …… First elastic disk (second elastic body) 47 …… Second elastic disk (third elastic body) 52 …… First rotation tilt axis, 53 …… Second rotation tilt axis 54 …… Left-wound spring (first elasticity) 55) Right-handed spring (first elastic body) 59 ... Gear train 60 ... First reference axis, 61 ... Second reference axis

Claims (1)

(57) [Claims] 1. A first rotating body rotatably mounted on a robot arm, and a first rotating body rotatably mounted on a first rotation tilt axis oblique to the first rotating body. A second rotating body that is rotatably provided around the second rotating body and a second rotating tilt axis that is parallel to the first rotating tilt axis, and has a robot hand mounting surface that is parallel to the robot arm. And a gear train that is provided between the first rotation tilt shaft and the second rotation tilt shaft and that rotates the other rotation tilt shaft in the same direction by rotation of the one rotation tilt shaft, A first elastic body provided between the robot arm and the first rotating body; a second elastic body provided between the first rotating body and the first rotation tilt axis; Third bullet provided between the rotation tilt axis and the third rotating body Comprising a body and a coupling for position correction of the robot hand.