JPH07276270A - Parallel link type articulated robot - Google Patents

Abstract

PURPOSE:To easily control the position and the posture of a hand in an articulated robot using a four joint parallel link for an arm by moving first and fifth joint means in the rectilinear direction by means of drive means so as to change the shape of parallelogram of the four joint parallel link. CONSTITUTION:A four joint parallel link is constituted of first - fourth link members 1-4, and first - fourth joints 6-9 combining the formers with turning materials. The first and fourth link members 1, 4, the second and third link members 2, 3 are opposed in parallel with each other. The third link member 3 is extended outside over the joint 7, and a fifth joint 5 is rotatably combined with the end part. The first and the fifth joints 6, 5 are respectively slidably engaged with linear guides 12, 13 arranged in the directions meeting at right angles, and the respective joints 5, 6 are respectively provided with drive means. The fourth link member 4 is extended outside the third joint 8, and the end part is provided with a hand 11 through a sixth joint 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel link type articulated robot using a four-bar parallel link for an arm.

[0002]

2. Description of the Related Art An industrial robot is composed of a hand portion (hand) for holding and operating an object, and an arm portion (arm) for transporting the hand to a predetermined position in a three-dimensional space. In particular, various arms have been proposed because the arm needs to support the hand and simultaneously move the object held by the hand in the three-dimensional space.

FIG. 7 is a diagram showing a basic structure of a conventional parallel link type articulated robot using a four-bar parallel link for an arm. This robot includes link members 70 to 74, joints 75 to 79, and a hand 7A. Link member 70
Has a joint (not shown) composed of an actuator that rotationally drives the entire robot. The joint 75 has an actuator that rotationally drives the link members 71 and 72 separately. That is, the joint 75 includes a first joint that rotationally drives the link member 71 and a second joint that rotationally drives the link member 72.
Composed of joints and.

The four-bar parallel link has four link members 71 to 71.
74 and four joints 75 to 78. Link member 71
And the link member 74 face each other in parallel, and the link member 72 and the link member 73 face each other in parallel. Link member 71
One end of which is connected to the first joint of joint 75 and the other end of which is joint 7
It is connected to 6 so that it can rotate freely. One end of the link member 72 is coupled to the second joint of the joint 75, and the other end is pivotally coupled to the joint 78. One end of the link member 73 has a joint 76.
The other end is pivotally connected to the joint 77. One end of the link member 74 is pivotally coupled to the joint 77, and the other end is coupled to the joint 79. Link member 74
Is rotatably connected to the link member 72 via a joint 78. The joint 79 is coupled to the end of the link member 74 and has an actuator for driving the hand 7A to rotate. The hand 7A has a joint (not shown) formed of an actuator that rotationally drives the entire hand.

The joint 75 has an actuator for rotationally driving the link members 71 and 72 as described above, but the joints 76 to 78 merely connect the link members 71 to 74 pivotably. Therefore, when the first joint of the joint 75 pivotally drives the link member 71, the shape of the four-node parallel link (the shape of the parallelogram) changes accordingly. Similarly, when the second joint of the joint 75 pivotally drives the link member 72, the shape of the four-node parallel link (parallelogram shape) changes accordingly. For example, in the state of FIG. 7A, when the first joint of the joint 75 pivots the link member 71 in the clockwise direction, the four-joint parallel link shape (parallelogram shape) is changed to that of FIG. ) Changes.
Similarly, when the second joint of the joint 75 pivots the link member 72 in the counterclockwise direction in the state of FIG. 7A, the shape of the four-bar parallel link (parallelogram shape) is correspondingly illustrated. It changes like 7 (C). In this way, the parallel link type articulated robot can position and control the hand 7A to a predetermined position by appropriately driving the turning positions of the link members 71 and 72 by the first and second joints of the joint 75.

[0006]

However, in the parallel link type articulated robot, when the hand 7A is to be moved along the dotted line rectangle ABCD as shown in FIG. The respective pivot positions of the link members 71 and 72 pivoted by the first joint and the second joint must be obtained by altitude calculation processing. That is, when the position and the posture of the hand 7A are designated, it is necessary to perform a considerably complicated coordinate conversion calculation to determine the command input amount to the first joint and the second joint of the joint 75. .

The present invention has been made in view of the above points, and provides a parallel link type articulated robot capable of easily controlling the position and posture of a hand without performing a complicated coordinate conversion calculation. The purpose is to

[0008]

A parallel link type articulated robot according to a first aspect of the present invention is connected to first link means and the first link means rotatably via the first joint means. A second link means, and a second link means for connecting the second link means to the second link means so as to be parallel to the second link means.
The third link means rotatably coupled through the joint means of the second link means and the second link means via the third joint means so as to be parallel to the first link means. A parallel link type multi-joint robot having a four-bar parallel link consisting of a fourth link means pivotally coupled to a third link means via a fourth joint means. A fifth joint means pivotally coupled to the end of the third link means extending outward and a sixth joint at the end of the fourth link means extending outward of the third joint means. Hand means coupled through the joint means, first driving means for driving the first joint means in the linear direction, and the fifth joint means for driving in the linear direction orthogonal to the linear direction. And a second drive means.

A parallel link type multi-joint robot according to a second aspect of the present invention is a first link means and a second link means rotatably coupled to the first link means via the first joint means. A third link means pivotally coupled to the first link means via a second joint means so as to be parallel to the second link means, and the first link means.
Connected to the second link means via a third joint means and to the third link means via a fourth joint means so as to be parallel to the second link means. In a parallel link type multi-joint robot having a four-bar parallel link composed of four link means, a fifth joint pivotally coupled to an end portion of the third link means extending outside the second joint means. Hand means connected to the end of the fourth link means extending to the outside of the third joint means via a sixth joint means, and the first and fifth joint means. And a means for driving the other so as to move on the moving plane of the four-bar parallel link.

[0010]

Operation The parallel link type articulated robot has a four-bar parallel link as a basic arm configuration. The four-bar parallel link is composed of four link means from first to fourth and four joint means from first to fourth that rotatably connect these. The first link means and the fourth link means face each other in parallel, and the second link means and the third link means face each other in parallel. The first link means is connected to the second link means via the first joint means, and is connected to the third link means via the second joint means.
Is rotatably connected to the link means. The fourth link means is pivotally coupled to the second link means via the third joint means and to the third link means via the fourth joint means. The third link means extends outside the second articulation means and has a fifth articulation means pivotally coupled to its end. Similarly, the fourth link means extends to the outside of the third articulation means, and has a hand means connected to the end thereof via the sixth articulation means.

In the first invention, the first driving means linearly drives the first joint means, and the second driving means linearly drives the fifth joint means in a direction orthogonal to the fifth joint means. When the first and fifth joint means move linearly by the first and second drive means, the parallelogram shape of the four-bar parallel link changes according to this movement, so that the position of the hand means The posture also changes. In the second invention, one of the first and fifth joint means is fixed, and the other is driven so as to move on the moving plane of the four-bar parallel link. The position and orientation of the hand means changes in accordance with the movement of either one of the fifth and fifth joint means. That is, the hand means moves in the same direction as the moving direction of the first joint means, and moves in the opposite direction to the moving direction of the fifth joint means.

In the first aspect of the invention, since the moving directions of the first and fifth joint means are orthogonal to each other as described above, the hand means moves on the orthogonal coordinate system. Also,
In the second invention, the first or fifth joint means is driven so as to move on the moving plane of the four-bar parallel link, that is, on the rectangular coordinate system, so that the hand means moves on the rectangular coordinate system. Become. Therefore, the moving positions of the first and fifth joint means in the first aspect of the invention and the movement of the first or fifth joint means in the second aspect of the invention can be calculated without performing a complicated coordinate transformation calculation as in the conventional art. The position and posture of the hand means can be easily controlled only by controlling the position.

In this case, the triangle formed by the first, second and fifth joint means and the first and third joints.
By setting the lengths of the link means so that the triangles formed by the sixth and sixth joint means are similar to each other, the first, second, and fifth joint means are formed. The triangle and the second triangle formed by the first, third and sixth joint means and the third triangle formed by the fifth, fourth and sixth joint means are similar figures, respectively. Therefore, when the first joint means moves, the hand means moves in the same direction as the moving direction by a distance corresponding to the similarity ratio of the first and third triangles, and similarly, the fifth joint. When the means moves, the hand means moves in a direction opposite to the moving direction by a distance according to the similarity ratio of the first and second triangles, so that the position and attitude of the hand means are controlled with high accuracy. can do.

[0014]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an embodiment of a parallel link type articulated robot of the present invention, and FIGS. 3 to 4 are diagrams showing operation states of the parallel link type articulated robot of FIG. This robot has link members 1 to 4 and joints 5 to 10
And the hand 11. The joint 5 is pivotally connected to one end of the link member 3 and is linearly driven in a direction along the linear guide 12 (X-axis direction). That is, the joint 5 moves along the linear guide 12 when the position of the joint 5 in the state of FIG.
A range from A to + A is linearly driven by an actuator (not shown) in the X-axis direction.

The joint 6 includes a link member 1 and a link member 2.
Is rotatably connected to one end of each of the above, and is linearly driven in the direction along the linear guide 13 (Z-axis direction). That is, the joint 6 is linearly driven by an actuator (not shown) in the Z-axis direction in the range from −B to + B along the linear guide 13 with the position of the joint 6 in the state of FIG. It has become. As the actuator that linearly drives the joints 5 and 6, various actuators such as a linear positioning device including a table and a ball screw and a linear positioning device using a cylinder can be applied.

The four-bar parallel link is composed of four link members 1-4.
And four joints 6-9. The link member 1 and the link member 4 face each other in parallel, and the link member 2 and the link member 3 face each other in parallel. One end of the link member 1 has a joint 6
The other end is pivotally connected to the joint 7.
One end of the link member 2 is pivotally connected to the joint 6, and the other end is pivotally connected to the joint 9. One end of the link member 3 has a joint 5
The other end is pivotally connected to the joint 8.
The link member 3 is pivotally connected to the link member 1 via a joint 7. One end of the link member 4 is pivotally connected to the joint 8, and the other end is connected to the joint 10. The link member 4 is pivotally connected to the link member 2 via a joint 9.

The distance between the joints 6 and 7 (the length of the link member 1), the distance between the joints 8 and 9 is XA, the distance between the joints 9 and 10 is XB, and the distance between the joints 6 and 9 is (The length of the link member 2) and the distance between the joint 7 and the joint 8 are Z
B and the distance between the joint 5 and the joint 7 is ZA. Therefore, the length of the link member 4 is XC = XA + XB,
The length of the link member 3 is ZC = ZA + ZB. At this time, the ratio of XA and ZA (XA: ZA) is made equal to the ratio of XC and ZC (XC: ZC). That is, X
A: ZA = XC: ZC. This is joint 5, 8, 1
This means that a triangle having 0 as its apex and a triangle having joints 5, 7, and 6 as its apex have similar shapes. This inevitably results in XA: ZA = XB: ZB, and the triangles having joints 5, 8, and 10 as vertices, the triangles having joints 5, 7, and 6 as vertices, and joints 6, 9, and 10 The triangles that form the vertices have similar shapes. In this example, X
A: ZA = XB: ZB = XC: ZC = 1: 1 and X
A: XB: XC = ZA: ZB: ZC = 1: 2: 3. It is needless to say that this similarity ratio is a design matter and may be appropriately changed according to the moving range and the like.

The joint 10 is connected to the end of the link member 4 and has an actuator for rotating the hand 11. The hand 11 has a joint (not shown) formed of an actuator that rotationally drives the entire hand. The joints 5 to 9 only connect the link members 1 to 4 so as to be rotatable. Therefore, the joint 5 is the linear guide 1
When moving in the X-axis direction along 2, the shape of the four-bar parallel link (the shape of the parallelogram) changes accordingly. Similarly, when the joint 6 moves in the Z-axis direction along the linear guide 13, the shape of the four-node parallel link (the shape of the parallelogram) changes accordingly. For example, in the state of FIG. 1, when the joint 5 moves along the linear guide 12 in the X-axis direction by + A,
Accordingly, the shape of the four-bar parallel link (parallelogram shape) changes as shown in FIG.

That is, in the state shown in FIG. 1, the joint 10 is located at the origin position (0,0). When the joint 5 moves in the + X-axis direction by A in this state, the joint 10 is correspondingly moved.
Moves in the opposite -X axis direction by twice the moving amount A of the joint 5 (2A), and stops at the coordinate position (-2A, 0). Joint 1
0 moves by twice the amount of movement of the joint 5 because the joint 6 does not change its position with the movement of the joint 5. Therefore, a triangle having the joint 6 as its apex, that is, the joints 5, 7, 6 as apex This is because the similarity ratio of each side of the triangle with and the triangle with the joints 6, 9, and 10 as vertices is 1: 2.

Next, when the joint 6 moves + B in the Z-axis direction along the linear guide 13 in the state shown in FIG. 2, the shape of the four-bar parallel link (parallelogram shape) is accordingly changed to that shown in FIG.
It changes like (A). That is, in the state of FIG.
The joint 10 is located at the coordinate position (-2A, 0). When the joint 6 moves B in the + Z-axis direction in this state, the joint 10 correspondingly moves B by the amount B of the joint 6 in the same + Z-axis direction.
3 times (3B) of the coordinate position (-2A, +3
Stop at B). The joint 10 moves three times as much as the movement amount of the joint 6 because the joint 5 does not change its position in accordance with the movement of the joint 6, so that the triangle having the joint 5 as an apex, that is, the joints 5, 7, and 6 Triangles and joints 5, 8
This is because the similarity ratio of each side to the triangle having 10 as its apex is 1: 3. Therefore, by appropriately changing the similarity ratio of each triangle, the moving amount (moving range) can be changed.

Similarly, in the state shown in FIG. 3A, when the joint 5 moves along the linear guide 12 in the X-axis direction by -2A, the shape of the four-bar parallel link (parallelogram shape) is correspondingly changed. The shape) changes as shown in FIG. That is, FIG.
In the state of (A), the joint 10 has coordinate positions (-2A, +3).
Located in B). In this state, if the joint 5 moves by 2 A in the −X axis direction, the joint 10 correspondingly moves in the opposite + X direction.
The joint 5 moves in the axial direction by twice the moving amount 2A of the joint 5 (4A), and stops at the coordinate position (+ 2A, + 3B).

In the state of FIG. 3 (B), when the joint 6 moves along the linear guide 13 in the Z-axis direction by -2B, the four-node parallel link shape (parallelogram shape) is accordingly changed to that shown in FIG. It changes like (A). That is, in the state of FIG. 3B, the joint 10 is located at the coordinate position (+ 2A, + 3B). In this state, when the joint 6 moves in the −Z-axis direction by 2B, the joint 10 moves in the same −Z-axis direction by 3 times (6B) the movement amount 2B of the joint 6, and the coordinate position (+ 2A, -3B).

When the joint 5 moves along the linear guide 12 by + 2A in the X-axis direction in the state of FIG. 4A, the shape of the four-node parallel link (parallelogram shape) is correspondingly changed to that of FIG. It changes like B). That is, in the state of FIG. 4A, the joint 10 is located at the coordinate position (+ 2A, -3B). When the joint 5 moves in the + X-axis direction by 2A in this state, the joint 10 moves in the opposite -X-axis direction by twice the moving amount 2A of the joint 5 (4A) and the coordinate position (-2A). , -3B).

When the joint 6 moves along the linear guide 13 by + B in the Z-axis direction in the state of FIG. 4B, the shape of the four-bar parallel link (the shape of the parallelogram) is corresponding to that of FIG.
The joint 10 stops at the coordinate position (-2A, 0). On the other hand, when the joint 6 moves along the linear guide 13 by + 2B in the Z-axis direction, the shape of the four-bar parallel link (parallelogram shape) is changed accordingly.
(A), the joint 10 moves to the coordinate position (-2A,
+ 3B) will come to a stop.

As described above, the parallel link type articulated robot of the present embodiment moves the joint 5 linearly along the linear guide 12 to move the hand 11 to the linear guide 12.
Can move parallel to the moving direction of the
Since the hand 11 can be moved in parallel with the moving direction of the linear guide 13 by linearly moving the hand along the linear guide 13, the position of the hand 11 can be calculated without performing complicated coordinate conversion calculation as in the prior art. And the posture can be easily controlled.

In the above-described embodiment, since the joint 10 has the actuator for turning the hand 11, the hand 11 is appropriately turned so that the hand 11 is controlled so as to face a certain direction. There is. When the actuator for rotating the hand 11 is provided in the joint 10 at the tip of the arm in this manner, the rigidity of each link member of the four-bar parallel link must be increased in order to support the weight of the actuator. Problem arises. Therefore, in the next embodiment, an actuator for rotating the hand 11 is provided in the joint 5 or the joint 6, and the turning drive force is transmitted via the newly provided first and second four-section parallel links. I did it.

FIG. 5 is a diagram showing another embodiment of the parallel link type articulated robot of the present invention, and FIGS. 6 to 8 are diagrams showing respective operating states of the parallel link type articulated robot of FIG. . In FIG. 5, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. This robot has an actuator for rotating the hand 11 in the joint 6, and the first and second link members 14 to 18 and the joints 19 to 21 newly provided with the rotation driving force are provided. It is configured to transmit by a four-bar parallel link.

The first four-section parallel link for transmitting the swing driving force is the link members 2, 14, 15, 16 and the joints 6, 9, 1.
The second four-bar parallel link is composed of link members 4, 16, 17, 18 and joints 9, 10, 20, 21.
Composed of. One end of the link member 2 is pivotally connected to the joint 6, and the other end is pivotally connected to the joint 9. One end of the link member 4 is pivotally connected to the joint 9, and the other end is pivotally connected to the joint 10. One end of the link member 14 is connected to an actuator for turning drive provided in the joint 6, and the other end is turnably connected to the joint 19. Link member 15
One end of is connected to the joint 19 and the other end is connected to the joint 20 so as to be freely rotatable. One end of the link member 16 is connected to the joint 9,
The other end is pivotally connected to each joint 20. One end of the link member 17 is pivotally coupled to the joint 20, and the other end is pivotally coupled to the joint 21. One end of the link member 18 is pivotally coupled to the joint 21, and the other end is mechanically coupled to the hand 11 via the joint 10.

In the first four-section parallel link, the link member 2 and the link member 15 face each other in parallel, and the link member 1
4 and the link member 16 face each other in parallel. In the second four-section parallel link, the link member 4 and the link member 17
Are parallel to each other, and the link member 16 and the link member 18 are parallel to each other. Therefore, the link member 14 and the link member 18 always maintain the parallel state via the link member 16, so that when the link member 14 is driven to rotate, the hand 11 also rotates in synchronization therewith.

FIG. 6 shows the shape of the first and second four-bar parallel links (parallelogram) when the joint 5 moves along the linear guide 12 in the X-axis direction by + A in the state of FIG. FIG. 6 is a diagram showing how the shape of FIG. That is, in the state of FIG. 5, the joint 10 is located at the origin position (0,0). When the joint 5 moves in the + X axis direction by A in this state, the joint 10 moves in the opposite −X axis direction by twice the movement amount A of the joint 5 (2A), and the coordinate position (−2A , 0). However, since the turning position of the link member 14 does not change at all, the hand 11 maintains the state shown in FIG. This is the same even when the positions of the joints 5 and 6 are variously changed as shown in FIGS. In the parallel link type articulated robot of this embodiment, it is not necessary to provide an actuator for rotating the hand 11 at the tip of the arm, and the rigidity of the robot can be determined by considering only the load of the arm and the transported object.
The weight of the arm itself can be reduced, and as a result, the hand 11
It becomes possible to control the position and posture of the robot at high speed.

In the above embodiment, the case where the joint 5 is moved in the X direction and the joint 6 is moved in the Z direction has been described. However, the invention is not limited to this, and the joint 5 is moved in the Z direction and the joint 6 is moved in the X direction. You can move it or fix joint 6 and move only joint 5 to X.
-Movement may be performed on the Z plane (that is, the movement plane of the four-bar parallel link).
It may move on the -Z plane. Further, in the above-described embodiment, the triangles having the joints 5, 8 and 10 as vertices, and the joints 5 and
Although the triangles having the vertices 7 and 6 and the triangles having the joints 6, 9 and 10 as the similar shapes have been described, they do not necessarily have to be similar shapes. That is, even if the triangles are not similar figures, the position and posture of the hand 11 can be controlled according to the moving directions of the joints 5 and 6. However, it goes without saying that if the triangles are similar, the position and orientation of the hand 11 can be controlled with high accuracy.

[0032]

According to the present invention, the position and orientation of the hand can be easily controlled without performing complicated coordinate conversion calculation.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a parallel link type articulated robot of the present invention.

FIG. 2 is a diagram showing an example of an operating state of the parallel link type articulated robot of FIG.

FIG. 3 is a diagram showing another example of the operating state of the parallel link type articulated robot of FIG. 1.

FIG. 4 is a diagram showing still another example of the operating state of the parallel link type articulated robot of FIG. 1.

FIG. 5 is a diagram showing another embodiment of the parallel link type articulated robot of the present invention.

FIG. 6 is a diagram showing an example of an operating state of the parallel link type articulated robot of FIG.

FIG. 7 is a diagram showing a configuration of a conventional parallel link type articulated robot.

[Explanation of symbols]

1, 2, 3, 4, 14, 15, 16, 17, 18, ... Link member, 5, 6, 7, 8, 9, 10, 19, 20, 21,
… Joints, 11… Hands, 12, 13… Linear guides

Claims (4)

[Claims] 1. A first link means, a second link means rotatably coupled to the first link means via a first joint means, and parallel to the second link means. So that the third link means pivotally coupled to the first link means via the second joint means and the second link means so as to be parallel to the first link means. A parallel link having a four-bar parallel link consisting of a fourth link means pivotably connected to the third link means via a third joint means to the third link means, respectively. In the multi-joint type robot, a fifth joint means pivotally coupled to an end of the third link means extending outside the second joint means, and extending outside the third joint means. And a sixth joint hand at the end of the fourth link means. A hand means coupled via a first drive means for driving the first joint means in a linear direction, and a second drive means for driving the fifth joint means in a linear direction orthogonal to the linear direction. A parallel link type articulated robot comprising a driving means. 2. A first link means, a second link means rotatably coupled to the first link means via a first joint means, and parallel to the second link means. So that the third link means pivotally coupled to the first link means via the second joint means and the second link means so as to be parallel to the first link means. A parallel link having a four-bar parallel link consisting of a fourth link means pivotably connected to the third link means via a third joint means to the third link means, respectively. In the multi-joint type robot, a fifth joint means pivotally coupled to an end of the third link means extending outside the second joint means, and extending outside the third joint means. And a sixth joint hand at the end of the fourth link means. And hand means coupled via a fixed one of the first and fifth articulation means,
A parallel link type multi-joint robot comprising: a means for driving the other so as to move on the moving plane of the four-bar parallel link. 3. The triangle formed by the first, second, and fifth joint means and the triangle formed by the first, third, and sixth joint means are similar to each other. 3. The parallel link type articulated robot according to claim 1, wherein the length of each link means is set. 4. The first or fifth joint means further comprises drive means for rotationally driving the hand means,
The driving force of the driving means is transmitted via first and second four-bar parallel links which are formed by sharing a part of the four-bar parallel links.
The parallel link type articulated robot described in 2 or 3.