JPH10166291A - Floating hand device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct an angular error of a work for the center axis of a latch hole and perform a smooth and sure insert and latch operation by providing error absorbing mechanisms absorbing angular errors for the latch part of a work on a hand mechanism and a supporting part. SOLUTION: A second error absorbing mechanism 25 provided on a hand mechanism 1 is in charge of the correction of an X-axis direction angular error. A first error absorbing mechanism provided on a supporting part is in charge of the correction of a Y-axis direction angular error. Namely, the second error absorbing mechanism 25 is applied and a pawl part 21 is revolved around a rotary spindle 20 by a prescribed angle, and the first error absorbing mechanism is applied and a receiving fitting is revolved around the rotary spindle 20 by the prescribed angle. Therefore, the center axis of a work W can be matched with the center axis of a latch hole (m) and natural insert and latch become possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floating hand device for gripping a work and inserting the work into a hook portion.

[0002]

2. Description of the Related Art The simpler the work, the more automation the robot performs on behalf of the worker is promoted. For example, the work of inserting and engaging a work, which is a shaft, into an engaging portion is a good example.

Conventionally, as shown in, for example, FIG. 17A, a floating hand device F is directly opposed to a mounting component N having a hooking hole m which is a hooking portion. This floating hand device F is provided with a gripper g, and the upper end of a shaft W which is a work is gripped.

If the central axis of the engaging hole m and the central axis of the shaft W are correctly aligned, the floating hand device F is operated to lower the gripper g along the axial direction. To be smoothly inserted and hooked.

Usually, the above-mentioned floating hand device F
Has an error absorbing mechanism e interposed between the gripper g and the main body arm d. This error absorbing mechanism e is called, for example, a compliance module (trade name).
It has a function of correcting a position error in the YZ directions and an angle error about the Y axis and the Z axis.

Although a specific configuration is not shown, a rolling bearing is interposed between the upper frame and the lower plate, and a restraining ring and a spring are sandwiched. Then, the lower plate is free while receiving a slight centripetal force by the restraining ring and the spring, and the lower plate is swingable with respect to the upper frame.

[0007] As shown in FIG. (B), shifted the position of the center axis s ₂ of the shaft W with respect to the central axis s ₁ of the engaging hole m, if there is a positional error and the angle error, the gripper g of shaft When the shaft W is lowered, the lower end of the shaft W comes into contact with the periphery of the engaging hole m, and a reaction force acts on the error absorbing mechanism e which is the compliance module.

This force acts on the restraining ring constituting the error absorbing mechanism e to move the lower plate horizontally or rotationally in the direction of the force. Thus, the error becomes that along the central axis s ₂ of the shaft W to the central axis s ₁ of the absorbed by engaging holes a, inserted into the engaging hole m of the shaft W is automatically possible.

[0009]

However, FIG. 18 (A)
There is a floating hand device Fa as shown in FIG.
Although the gripper g of this device grips the upper end of the shaft W as a work, there is no difference, but there is a large offset between the gripping center and the rotation center O of the error absorbing mechanism e.

[0010] In the case of this device Fa, if there is a central axis s ₂ to the angle error of the shaft W with respect to the central axis s ₁ of the engaging hole m, the error absorption mechanism e is necessarily to be able to absorb the error Absent.

That is, the moment acting from the mounting component N is always in one direction with respect to the rotation center O of the error absorbing mechanism e for correcting the angle error, regardless of the direction in which the component is displaced. The mechanism rotates in a fixed direction, which is the angle θ, and cannot absorb the angle error.

Further, as shown in FIG. (B), the rotation center O of the gripping center and the error absorption mechanism e gripper g _a has the same axis, and gripping an elongated workpiece (shaft) Wa In the floating hand device Fb having a configuration that is convenient to perform, the error absorbing mechanism e can correct a certain degree of angular error as described above.

[0013] However, since the workpiece is an elongated shaft Wa, the substantially intermediate portions gripper g _a grips,
The holding posture of the shaft Wa is maintained. Accordingly, the pawl stroke l of the gripper g _a becomes inevitably long, cause a decrease in rigidity, there was a negative impact on durability and reliability.

For this reason, it is desirable that the center of rotation of the error absorbing mechanism e be shifted from the center of the gripping portion with respect to the long shaft Wa. That is, in the configuration shown in FIG. 9A described above, the gripper b needs only a short stroke, and the upper half of the long shaft Wa may be projected upward from the gripper.

In the configuration shown in FIG. 1A, a long shaft W
a is suitable for the gripping operation and the insertion engaging operation, but the rotation center O of the error absorbing mechanism e is separated from the gripping center of the work,
There is a problem that angle error cannot be corrected.

Conventionally, when an RCC (Remote Center Compliance) hand device or a floating hand device can be used, a position error or an angle error is corrected using these devices.

If these cannot be used, the force applied to each of the XYZ axes and the six-axis force of the moment around each axis are calculated using a force sensor composed of a strain gauge, and the force applied to each axis is calculated. The position error and the angle error are corrected by so-called six-axis control software for controlling the force to be zero.

However, in order to perform six-axis control, costly devices such as a six-axis force sensor and a six-axis robot are required, and the control method is complicated, and is not suitable for actual use. .

The present invention has been made in view of the above circumstances. It is an object of the present invention to provide a rotation center of an error absorbing mechanism along a work holding center axis.
An object of the present invention is to provide a floating hand device which absorbs a shift of a center axis of a work with respect to a center axis of a hooking hole, enables smooth and reliable insertion hooking operation, and improves workability.

[0020]

According to a first aspect of the present invention, there is provided a floating hand device comprising: a hand mechanism having a claw for gripping a workpiece; and a supporter for supporting the hand mechanism. Wherein the first mechanism and the second mechanism are provided with a first error absorbing mechanism and a second error absorbing mechanism for absorbing an angular error with respect to the work engaging portion. It is characterized by having.

According to a second aspect of the present invention, the first error absorbing mechanism and the second error absorbing mechanism according to the first aspect of the present invention provide a rotary support shaft for connecting a fixed-side component and a rotary-side component constituting a hand mechanism and a support portion, respectively. And an elastic body provided in the vicinity of the rotation support shaft and interposed between the fixed-side component and the rotation-side component, wherein the rotation support shafts are provided in a direction orthogonal to their central axes. I do.

According to a third aspect of the present invention, the elastic bodies constituting the first and second error absorbing mechanisms according to the second aspect of the present invention include a pair of compression coil springs and leaf springs provided on both left and right sides of the rotating shaft. It is characterized by being either one.

According to a fourth aspect of the present invention, the elastic body constituting the first error absorbing mechanism and the second error absorbing mechanism according to the second aspect is an elastic sheet interposed between a rotating component and a fixed component. It is characterized by being.

According to a fifth aspect of the present invention, the elastic body constituting the first error absorbing mechanism and the second error absorbing mechanism according to the second aspect is wound around the peripheral surface of the rotary support shaft, and the peripheral portion thereof is formed. It is a spiral spring that elastically contacts the rotating part.

According to the first aspect of the present invention, by adopting the means for solving such a problem, the angle error can be reliably absorbed, and the work can be reliably inserted into the engaging portion. According to the second aspect of the present invention, when an external force is applied to the claw portion of the hand mechanism by the action of the rotation support shaft and the elastic body,
It rotates (inclines) by a certain angle according to the force, and returns to the initial posture when there is no external force.

When the external force is applied by the action of the rotating shaft and the elastic body, the supporting portion supporting the hand mechanism also rotates (inclines) by a certain angle according to the force, and returns to the initial posture when the external force is removed.

Since the rotation support shaft of the first error absorbing mechanism and the rotation support shaft of the second error absorption mechanism are arranged so as to intersect at right angles, the held work changes its posture in an arbitrary direction. Along the hooks of the mounting parts. Therefore,
Insertion and engagement of the work into the engagement portion can be performed.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the floating hand device includes a hand mechanism 1 for gripping a work, which will be described later, and a support unit 2 that supports the hand mechanism 1 and is attached to a robot body (not shown).

First, the support section 2 will be described. 3 in the figure
Is a flange provided in the horizontal direction, which is attached and fixed to the robot body by appropriate means. This flange 3
, The upper end of the support plate 4 is attached and fixed to form a T-shape in side view.

A support base 5 is mounted and fixed to the lower end of the support plate 4 using mounting screws or the like. A mounting hole 6 is provided in the center of the support plate 4 and the support base 5 so as to communicate with each other, and the rotation support shaft 7 penetrates therethrough.

A nut 8 for mounting and fixing the rotation shaft 7 is inserted into the mounting hole 6 of the support plate 4. The rotation support shaft 7 is fitted into the mounting hole 6 of the support base 5 via a pair of bearings 9. That is, the supporting base 5
The rotation shaft 7 is rotatably supported.

The rotating shaft 7 protrudes from the end surface of the supporting base 5, and a receiving bracket 11 is attached and fixed via a holding plate 10. The receiving fitting 11 is bent in an L-shaped cross section along the front surface and the upper surface of the support base 5.

Then, the upper surface of the support base 5 and the receiving fitting 11
The spring receiving recesses 12 are respectively provided at left and right symmetrical positions around the rotation support shaft 7 on the lower surface side of the upper surface. A compression spring 13 made of an elastic body is interposed between the opposed spring receiving recesses 12. The rotation support shaft 7 and the pair of compression springs 13 constitute a first error absorbing mechanism 14 for absorbing an error in the Y direction.

Therefore, while the support base 5 is a fixed part mounted and fixed to the robot body via the support plate 4 and the flange 3, the receiving bracket 11 is rotatable about the rotation support shaft 7. Side components. This rotation range is regulated by a stopper 15 mounted on the upper surface of the support base 5.

In addition, since the compression spring 13 is interposed in the spring receiving recess 12 of each of the support base 5 and the receiving fitting 11, if a load is input to the receiving fitting 11 via the hand mechanism 1, the supporting spring is supported. When the gap between the upper surface of the base 5 and the upper surface of the receiving member 11 is deviated from parallel, the inclination of only the receiving member 11 is generated, and when the input is removed, the elastic force of the compression spring 13 is removed and the upper surface of the upper surface of the receiving member 11 is removed again. A parallel state of the gap is obtained.

On the upper surface of the receiving member 11, a hand receiving member 17 is attached and fixed via an auxiliary receiving member 16.
A pair of mounting pieces 17a is protruded from the side surface of the hand receiving member 17 opposite to the side of the auxiliary receiving member 16, and the hand mechanism 1 is directly mounted here.

As shown in FIG. 2, the hand mechanism 1 includes a pair of claw receivers 19 mounted on the mounting pieces 17a of the hand receiver 17 via fixing screws 18, and end portions of these claw receivers 19. And a pair of claw portions 21 pivotally supported through a rotation support shaft 20.

To be more specific, the claw receiver 19 has a vertical portion 19a which is attached to the mounting piece 17a, and which protrudes from the lower end in the direction opposite to the hand receiving member 17. A portion 19b and a mounting piece 19c that is bent in the vertical direction at the tip of the horizontal piece are integrally formed.

The rotation support shaft 20 is provided at the center of the mounting piece 10 c of the claw receiver 19 so as to protrude inward, and is fixed to the claw receiver 19. A bearing 22 is embedded in the claw portion 21, and a protruding end portion of the rotation support shaft 20 is fitted into the bearing 22.

Accordingly, while the claw receiver 19 is a fixed-side component, the claw portion 21 is a rotatable-side component rotatable about the rotation support shaft 7 as a fulcrum. This rotation range is claw 2
1 is regulated by a stopper (not shown) mounted on the upper surface.

On the upper surface of the claw 21 and the lower surface of the claw receiver horizontal piece 19b, spring receiving recesses 23 are respectively provided at left and right symmetrical positions with the rotation support shaft 20 as a center. A compression spring 24 made of an elastic body is interposed in the spring receiving recess 23. The rotation support shaft 20 and the pair of compression springs 24 absorb a second angle error in the X direction.
Is configured.

In particular, a screw hole 21a is provided in communication with the spring receiving concave portion 23 of the claw portion 21, and an adjusting screw 26 is screwed into the screw hole 21a. The upper end of the adjusting screw 26 is in contact with the compression spring 24, and by pushing up this spring, the elastic force of the compression spring 24 can be adjusted according to the amount of pushing up.

The compression spring 24 includes the claw 21 and the claw holder 1.
9, if a load is input to the claw receiver 19 via the claw portion 2, the gap between the upper surfaces of the claw portion 21 and the claw receiver 19 becomes parallel. If the claws 21 are displaced and tilted and the input is removed, the elastic force of the compression springs 24 is removed, and the gaps between the upper surfaces of the claws 21 are again in a parallel state.

The claws 21 have claws on their opposing surfaces so that they can grip the workpiece W. As described above, a shaft is used here as the work W, and the engaging portion m of the attachment component N indicates an engaging hole.

Using such a floating hand device F, a shaft W as a work is engaged with an engaging hole m as an engaging portion. That is, the shaft W is gripped by the claw portion 21 and inserted into and engaged with the engaging hole m of the attachment component N. At this time, there is a positional error or an angular error between the central axis of the engaging hole m and the central axis of the workpiece W. Ideally there is no. However, in practice, there is usually a positioning error between the two.

For example, as shown in FIG.
And the central axis Sa of the shaft W gripped by the claw portion 21 of the hand mechanism 1 is the central axis s of the engaging hole a of the attachment part A.
_In some cases, it is inclined by an angle θ in the X direction with respect to ₁ .

When the shaft W is to be inserted into the engaging hole a by lowering the floating hand device as it is, the shaft W is hooked around the upper end of the engaging hole m and receives a reaction force from the component N. Therefore, the claw portion 21 rotates counterclockwise, which is the direction of the arrow in FIG.

As shown in FIG. 6, the second error absorbing mechanism 2
5 acts to correct the angle error. That is, the claw portion 21 rotates by the angle θ via the rotation support shaft 20, and the center axis Sa of the shaft W gripped here and the center axis s of the engagement hole m
₁ matches. Therefore, the angle error in the X direction with respect to the engaging hole m of the shaft W is corrected.

At this time, each compression spring 24 gives the claw portion 21 an appropriate compliance which is an elastic force necessary for correcting an error in the X direction. As shown in FIG. 7 (A), the support 2 supporting the hand mechanism 1 is provided with a shaft W
With respect to the central axis Sb is engaging hole central axis s ₂ of m in some cases is inclined by an angle β in the Y direction.

When the shaft W is to be inserted into the engaging hole m by descending the floating hand device, the shaft W is hooked around the upper end of the engaging hole m and receives a reaction force from the component N. Therefore, the second error absorbing mechanism 25 operates.

As shown in FIG. 6, one of the compression springs 13 expands and contracts, and the other compression spring 13 compresses.
The receiving bracket 11 rotates clockwise in the direction of the arrow in FIG.

Therefore, the center axis Sb of the shaft W held in the Y direction in the Y direction coincides with the center axis s ₂ of the engaging hole m, and the angular error of the shaft W in the Y direction with respect to the engaging hole m is the first error. The correction is made in the absorption mechanism 14.

At this time, each compression spring 13 gives the hand mechanism 1 an appropriate compliance which is an elastic force necessary for correcting an error in the Y direction. The above can also be explained from the state of correction for the angle error in an arbitrary direction shown in FIGS.

In the figure, A is the central axis of the work W, and here the axial direction is oriented in the Z-axis direction. B is the central axis of the engaging portion m of the part N, and this axial direction is
Is shifted in the Y direction along with the X direction.

The correction of the angle error in the X-axis direction is performed by the second error absorbing mechanism 25 provided in the hand mechanism 1, and the correction of the angle error in the Y-axis direction is performed by the first error provided in the support unit 2. The absorption mechanism 14 is in charge.

That is, the second error absorbing mechanism 25 operates to rotate the claw 21 about the rotation support shaft 20 by the angle ab, and the first error absorbing mechanism 14 operates to rotate the receiving metal 11. It rotates by an angle bc around the support shaft 20.

Therefore, the center axis of the workpiece W is
Can be made to coincide with the central axis, and a reasonable insertion engagement becomes possible. FIGS. 10 and 11 show an example in which the floating hand device Fs of the present invention is attached to an orthogonal 3-axis robot R. Here, a triaxial force sensor T is interposed between the triaxial robot R and the floating hand device Fs.

The three-axis force sensor T is a force sensor capable of measuring the translational force in the X, Y, and Z directions.
At the same time, it is electrically connected to the robot control unit 30 to perform three-axis control.

That is, of the position error and the angle (posture) error of the shaft W, the floating hand device Fs of the present invention corrects the angle error, and corrects the position error by three.
This is performed by controlling the axial force.

FIG. 12 is a block diagram of a control system of a device in which the floating hand device Fs of the present invention is mounted on an orthogonal three-axis robot R. In this example, the claw 21
The target position of the shaft W, the target value of the speed and the target value of the insertion force are set, the position error is corrected by the three-axis force control, and the angle error is mechanismd by the floating hand device Fs attached to the three-axis robot R. Is corrected.

Since such a combination of the three-axis force control robot R and the floating hand device Fs is used, compared to the conventional six-axis force control, a costly device is not required and the control method is reduced. Simplification is advantageous.

In the above embodiment, the elastic members constituting the first and second error absorbing mechanisms 14 and 25 are
Although the compression springs 13 and 24 are employed, the present invention is not limited to this, and may be replaced with an elastic body described below.

In FIG. 13, in the second error absorbing mechanism 25 constituting the support portion 2, rubber or urethane is used as an elastic body interposed between the upper surface of the support base 5 and the upper surface piece of the receiving fitting 11. An elastic member 31 such as a foam
The same operation and effect as those of the compression springs 13 and 24 can be obtained by interposing.

In FIG. 14, on both sides of the receiving bracket 11,
One end of a pair of leaf springs 32 which are elastic bodies is attached and fixed. These leaf springs 32 are folded so as to be interposed between the upper surface of the receiving fitting 11 and the upper surface piece of the support base 5.

Then, the receiving fitting 11 and the supporting base 5
The end of each leaf spring 32 folded in between is elastically in contact with the upper surface of the support base 5. From this, each leaf spring 32 has the same operation and effect as the compression springs 13 and 24.

FIG. 15 shows an example in which a spiral spring 33 as an elastic body is interposed in a gap formed between the front piece of the receiving member 11 and the front portion of the support base 5. This spiral spring 3
Numeral 3 is wound around the peripheral surface of the rotary support shaft 7 that pivotally supports the receiving fitting 11, and a part thereof elastically contacts the upper surface of the receiving fitting. From this, the spiral spring 33 is connected to the compression spring 1.
The same operation and effect as those of 3, 24 can be obtained.

As shown in FIG. 16A, when the workpiece is a long shaft Wa, the claw 21 grips a substantially middle portion of the shaft Wa. That is, no matter how long the portion of the shaft Wa protruding from the claw portion 21 is, the gripping center of the claw portion 21 is offset from the center of the support portion 2, so that it is gripped without any trouble, and Corrects angle errors.

As shown in FIG. 7B, a long shaft ma is prepared as _a hook portion, and a ring Wc as a work may be hooked here. In other words, opposed to the shaft m _a grip the ring Wc the claw portion 21 of the hand mechanism 1, interpolation fitting forms a correction described above.

As described above, no matter how long the stroke of inserting the ring Wc to the predetermined position is, the gripping center of the claw portion 21 is offset from the center of the support portion 2 so that the gripping can be performed without any trouble. And correction of the angle error. In addition, various modifications can be made without departing from the scope of the present invention.

[0070]

As described above, according to the first aspect of the present invention, the hand mechanism and the supporting portion are provided with the first error absorbing mechanism and the second error absorbing mechanism for absorbing an angle error with respect to the engaging portion of the work. .

According to the second aspect of the present invention, the first and second error absorbing mechanisms include a rotating shaft connecting the fixed component and the rotating component, and an elastic body interposed between the fixed component and the rotating component. And the center axes of the rotating shafts are orthogonal to each other.

According to the third aspect of the present invention, the elastic body is one of a pair of a compression coil spring and a leaf spring provided on the left and right sides of the rotary support shaft. In the invention of claim 4,
The elastic body was an elastic sheet interposed between the rotating component and the fixed component.

According to the fifth aspect of the present invention, the elastic body is a spiral spring wound around the peripheral surface of the rotary support shaft, the peripheral portion of which is elastically in contact with the rotating component. Therefore, according to the invention of each claim, while having a relatively simple configuration, the angle error of the work with respect to the center axis of the engagement hole is corrected, and a smooth and reliable insertion engagement operation is enabled, thereby improving workability. It produces effects such as being able to be achieved.

[Brief description of the drawings]

FIG. 1A is a side view of a floating hand device according to an embodiment of the present invention. FIG. 3B is a cross-sectional plan view of a support part that constitutes the floating hand device. (C) is a partial vertical cross-sectional view of the support portion.

FIG. 2A is a cross-sectional plan view of the floating hand device according to the embodiment, in which a part of a hand mechanism is omitted. (B) is a partial vertical sectional view of the hand mechanism.

FIG. 3 is an exploded perspective view of the floating hand device of the embodiment.

FIG. 4 is a perspective view of the floating hand device of the embodiment.

FIG. 5 is a view for explaining a hooking operation of the embodiment.

FIG. 6 is a diagram showing a hooked state according to the embodiment;

FIG. 7A is a diagram illustrating a hooking action of the embodiment. (B) is a diagram of a hooked state.

FIG. 8 is a diagram illustrating the angle correction in the embodiment in a three-dimensional manner.

FIG. 9 is an exemplary plan view illustrating angle correction according to the embodiment;

FIG. 10 is a view of a floating hand device mounted via a three-axis force sensor according to another embodiment.

FIG. 11 is a perspective view of a floating hand device attached to the orthogonal three-axis force robot according to the embodiment;

FIG. 12 is a block diagram of a control system according to the embodiment;

FIG. 13A is a longitudinal sectional view illustrating a shape of an elastic body according to another embodiment. (B) is the longitudinal front view.

FIG. 14A is a side view showing a shape of an elastic body according to still another embodiment. (B) is the longitudinal front view.

FIG. 15A is a side view showing the shape of an elastic body according to still another embodiment. (B) is the longitudinal front view.

FIG. 16A is a diagram illustrating a state where a long workpiece is gripped according to still another embodiment. (B) is a figure of the engagement state of the long engagement part of other embodiment.

FIG. 17 (A) is a diagram of a conventional engagement state of a work.
(B) is a diagram in the case where there is a conventional misalignment of the work with respect to the engaging portion.

FIG. 18A is a diagram of a further different conventional floating hand device. (B) is a different conventional,
The figure of a floating hand device.

[Explanation of symbols]

 W: Work (shaft), 21: Claw, 1: Hand mechanism, 2: Support, N: Mounting part, m: Engagement part (engagement hole), 14: First error absorbing mechanism, 25: Second Error absorbing mechanism, 7: rotating shaft, 20: rotating shaft, 13: elastic body (compression spring), 24: elastic body (compression spring).

Claims (5)

[Claims] 1. A floating hand device, comprising: a hand mechanism having a claw for gripping a work; and a support for supporting the hand mechanism, wherein the work is hooked on a hook of a mounting component. A floating hand device comprising: a first error absorbing mechanism and a second error absorbing mechanism that are provided on a support portion and absorb an angle error of a workpiece with respect to a hook portion. 2. A first error absorbing mechanism and a second error absorbing mechanism according to claim 1, wherein a rotating support shaft for connecting a fixed side component and a rotating side component constituting a hand mechanism and a support portion, respectively, A floating hand, comprising an elastic body provided near the rotation support shaft and interposed between the fixed-side component and the rotation-side component, wherein the center axes of the rotation support shafts are provided in a direction orthogonal to each other. apparatus. 3. The elastic body constituting the first error absorbing mechanism and the second error absorbing mechanism according to claim 2, wherein the elastic body is one of a pair of a compression coil spring and a leaf spring provided on both left and right sides of a rotating shaft. A floating hand device, which is one of them. 4. The elastic body constituting the first error absorbing mechanism and the second error absorbing mechanism according to claim 2 is an elastic sheet interposed between a rotating component and a fixed component. A floating hand device characterized by the above-mentioned. 5. The elastic body constituting the first error absorbing mechanism and the second error absorbing mechanism according to claim 2 is wound around a peripheral surface of the rotary support shaft, and the peripheral portion is provided on the rotating side. A floating hand device, which is a spiral spring that elastically contacts a part.