JP2001038671A - Articulated robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a singular point by a simple method without reducing the operational speed of an arm. SOLUTION: This robot is provided with first to sixth arms 5-10 connected via first to sixth joints J1-J6 to form an articulated arm 2 on a base 4. In a regular condition, a hand 3 is directly mounted on a fitting flange surface 11 at a tip of the sixth arm 10, and a spacer 14 for shifting a singular point having an angle can be mounted between the sixth arm 10 and the hand 3. When the hand 3 faces downwardly, and the fourth joint J4 is located concentric with the sixth joint J6, the singular point is generated, and a singular point line SO when no spacer 14 is mounted is changed to a singular point line S1 by mounting the spacer 14, and the singular point can be easily avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an articulated robot having a hand attached to the tip of an articulated arm, and more particularly to an articulated robot having an improved singularity avoiding structure.

[0002]

For example, in a multi-joint (6-axis) type robot that performs an assembly operation or the like, the position of each axis (joint) for each sampling time is determined based on the continuous trajectory of the position and posture of the hand. , Each joint is controlled while obtaining the velocity using an inverse Jacobian matrix. In this case, in general, in an articulated robot, a singular point in which two axes are coaxially positioned and an axis positioned between the two axes performs an irregular operation.
Exists, and there is a problem that the vicinity cannot be passed by the CP operation (the inverse Jacobian matrix cannot be obtained).

As a technique for avoiding such a singular point, a software method such as that disclosed in Japanese Patent Application Laid-Open No. Hei 5-324044 has been conventionally considered. In this technique, near the singular point, the speed at which the joint is driven is changed to a speed lower than the maximum speed of the joint, and the interval between the interpolation points is shortened, thereby passing the vicinity of the singular point. . However, this method has a drawback that the CP speed decreases near the singular point, and the ability originally provided by the robot cannot be exhibited, and the working time becomes longer.

On the other hand, as a simple solution for avoiding a singular point, it is conceivable to change the layout of peripheral equipment with respect to the robot, or change the installation position or angle of the robot. This makes it possible to shift the position of the singular point relative to the work space so that it does not have to pass near the singular point. However, there is a situation where it is impossible to determine whether or not the singularity is affected unless the robot is actually operated.Therefore, changing the layout of the equipment or changing the installation position or angle of the robot is a major equipment change And it was not an effective method.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an articulated robot capable of avoiding a singular point by a simple method without lowering the operation speed. It is in.

[0006]

SUMMARY OF THE INVENTION The present inventors have developed an articulated robot in which the existence of a singular point cannot be avoided. Focus on whether the position where the singularity occurs can be changed, and by configuring a spacer for changing the singularity between the tip of the arm and the hand, the position of the singularity can be easily set in the work space. The inventors have confirmed that they can be shifted relatively to each other, and have accomplished the present invention.

In other words, according to the articulated robot of the first aspect of the present invention, the arm does not have to be mounted between the tip of the arm and the hand for changing the singular point, and the arm has the mounted state. Is changed, the position of the joint of the arm and thus the position of the singular point are changed even if the hand is at the predetermined position and posture. Therefore, even in the vicinity of a singular point where passage is impossible in the state where the spacer is not attached, the position of the singular point can be shifted relative to the work space by attaching the spacer. Can be avoided to allow passage.

In this case, the robot can be operated without lowering the speed. Since the spacer is arranged between the end of the arm and the hand, which is a position where the spacer can be easily attached and detached, it is not necessary to make a large-scale equipment change, and the spacer can be easily attached and detached. . Therefore, according to the first aspect of the invention, there is an excellent effect that a singular point can be avoided by a simple method without lowering the operation speed.

Further, the spacer can be configured such that the surface to be mounted of the hand is inclined with respect to the mounting flange surface at the tip of the arm (the invention of claim 2).
Alternatively, the spacer may be configured such that the mounting angle of the hand with respect to the mounting flange surface at the tip of the arm can be changed (the invention of claim 3). According to these, the position of the singular point can be greatly shifted compared to the case where the mounting surface of the hand is displaced parallel to the mounting flange surface at the tip of the arm, which is effective.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention (corresponding to claims 1 and 2) will be described below with reference to FIGS. 1 and 2 show an external configuration of a main body 1 of the articulated robot according to the present embodiment. Here, the main body 1 of the robot is an articulated (for example, 6-axis) type arm 2.
For example, a hand 3 for gripping a work is attached to the tip of the.

More specifically, the arm 2 is configured as follows. That is, the first arm 5 is connected to the base 4 fixed to the installation surface of the facility so as to be rotated (turned) about the vertical axis via the first joint J1. At the tip of the first arm 5, a second arm 6
Are connected so as to be rotated (turned) about a horizontal axis via a second joint J2. The third arm 7 is connected to the tip of the second arm 6 via a third joint J3 so as to be rotated (turned) about a horizontal axis.

A fourth arm 8 is connected to the distal end of the third arm 7 via a fourth joint J4 so as to be coaxially rotated. A fifth arm 9 is connected to a tip of the fourth arm 8 so as to be rotated (turned) via a fifth joint J5. A sixth arm 10 is connected to the distal end of the fifth arm 9 via a sixth joint J6 so as to be coaxially rotated. Although not shown, each joint J
1 to J6 are respectively driven by actuators such as servo motors, and these actuators are controlled by a control device including a microcomputer or the like. The hand 3 is also controlled by the control device.

A circular mounting flange surface 11 as shown in FIG. 3 is provided at the tip of the sixth arm 10 so that the hand 3 can be mounted. At this time, the mounting flange surface 11 is provided with a circular fitting concave portion 11a at a central portion, and four screw holes 11b are formed on an outer peripheral side thereof at equal intervals (90 ° intervals) in a circumferential direction. And two screw holes 11b on the right side in the figure.
A pin insertion hole 11c is provided at an intermediate position between them.

On the other hand, the hand 3 is provided with a circular mounting surface 12 as shown in FIG. A ring-shaped fitting protrusion 12a corresponding to the fitting recess 11a is provided at the center of the attachment surface 12, and
Four bolt insertion holes 12b are formed on the outer peripheral side thereof at equal intervals, and two bolt insertion holes 1 on the left side in FIG.
A hole 13 is provided in the middle of 2b in which a knock pin (not shown) for positioning is arranged.

The hand 3 is attached to the tip of the sixth arm 10 by attaching four bolts (not shown) with the surface 12 to be attached to the mounting flange surface 11. This is performed by tightening the screw holes 11b through the insertion holes 12b.
Are fitted into the fitting recesses 11a, and the knock pins are inserted into the pin insertion holes 11c, whereby positioning is performed.

Now, in the main body 1 of the robot,
As shown in FIG. 1, a spacer 1 for changing a singular point is provided between the tip of the arm 2 (sixth arm 10) and the hand 3.
4 is configured to be attachable. As shown in FIGS.
In the present embodiment, this spacer 14 is
And the flange plate 16 are joined together.

As shown in FIG. 8, the inclined block 15 has a shape like a thin cylinder cut along a plane inclined with respect to the center axis, and has one end face (perpendicular to the center axis). Surface) is the robot mounting surface 17, and the other end surface, that is, the surface on the side inclined with respect to the central axis is the bonding surface 18. Four bolt insertion holes 15a are provided at equal intervals (90 ° intervals) in the portion near the outer periphery of the robot mounting surface 17 so as to penetrate the robot mounting surface 17 and the joint surface 18. Are formed so as to extend in a direction orthogonal to. These bolt insertion holes 15a are formed in a stepped shape in which a predetermined thickness portion on the robot mounting surface 17 side is reduced in diameter.

The robot mounting surface 17 of the inclined block 15 has a ring-shaped fitting projection 17a located at the center corresponding to the fitting recess 11a of the mounting flange surface 11 of the sixth arm 10. And a knock pin 19 for positioning corresponding to the pin insertion hole 11c.
(Shown only in FIG. 6). In this embodiment, the inclination angle θ of the joining surface 18 with respect to the robot mounting surface 17 is, for example, 30 °.

As shown in FIG. 8 (a), the joint surface 18 of the inclined block 15 is provided with a ring-shaped fitting projection 18a located at a central portion thereof and has an outer periphery thereof. Side, three screw holes 18b, a pin insertion hole 18c through which the knock pin 19 is inserted, and a pin insertion hole 1
8d are formed. Of these, three screw holes 18b
And four of the pin insertion holes 18c are
a are provided at equal intervals (90 ° intervals) at positions 45 ° in the circumferential direction from a, and the pin insertion holes 18d are provided at positions 22.5 ° shifted from the pin insertion holes 18c. .

On the other hand, the flange plate 16 is
As shown in FIG. 5, the ring-shaped member has a fitting hole 16a at the center, and one surface thereof (the surface on the right side in FIGS. 5 and 9B) is a joining surface 20, and the other surface is a joining surface 20. A tool mounting surface 21 is provided. As shown in FIG. 9A and FIG.
Similarly to the mounting flange surface 11 of the sixth arm 10, the tool mounting surface 21 has four screw holes 21a located on the outer peripheral side of the fitting hole 16a at equal intervals in the circumferential direction (90).
(Interval at an angle of 45 °), and furthermore, at the middle of the two screw holes 21a on the right side in the figure (position shifted by 45 °),
A pin insertion hole 21b is provided.

The flange plate 16 is provided with three bolt insertion holes 16b and a pin insertion hole 16c so as to penetrate both surfaces 20, 21 thereof. The bolt insertion hole 16b is
It is formed in a stepped shape with a small diameter on the 0 side, and three are formed at positions (positions excluding the pin insertion hole 21b) which are circumferentially shifted by 45 ° from the screw holes 21a. Further, the pin insertion hole 16c is two
It is provided at a position shifted by 2.5 °.

Thus, the inclined surface 15 and the flange plate 16 are brought into contact with the joint surface 18 and the joint surface 20 in a state where the fitting projection 18a of the inclined block 15 is fitted in the fitting hole 16a. Then, the three bolts 22 (see FIGS. 5 and 7) are screwed into the screw holes 18b through the bolt insertion holes 16b, respectively.
It is joined by screwing into. At this time, the knock pin 23 (shown only in FIG. 5) is inserted into the pin insertion hole 16.
By inserting the pin through the pin c into the pin insertion hole 18d, both are positioned.

When the spacer 14 configured as described above is mounted between the tip of the sixth arm 10 and the hand 3, first, the inclined block 15 alone is attached to the mounting flange surface 11 of the sixth arm 10. Attached to In this mounting, the fitting convex portion 17a of the inclined block 15 is
1a, and the dowel pin 19 is inserted into the pin insertion hole 11c and the robot mounting surface 17 is positioned on the mounting flange surface 11, and four bolts 24 (see FIG. 5) are positioned. By screwing into the screw holes 11b through the bolt insertion holes 15a, respectively.
At this time, the head of each bolt 24 is attached to the bolt insertion hole 1
5 a, and does not protrude from the joint surface 18.

Next, as described above, the inclined block 1
The flange plate 16 is bonded to the fifth bonding surface 18. Also in this case, the head of each bolt 22 is located in the bolt insertion hole 16b and does not protrude from the tool mounting surface 21. Thereafter, the tool mounting surface 2 of the spacer 14 is
The hand 3 is attached to 1. This attachment is performed in a state where the fitting projection 12a of the attachment surface 12 is fitted into the fitting hole 16a of the flange plate 16 and the knock pin (not shown) is inserted into the pin insertion hole 18c to perform positioning. The mounting is performed by directing the mounting surface 12 to the tool mounting surface 21 and screwing four bolts (not shown) into the screw holes 18b through the bolt insertion holes 12b.

In this manner, the spacer 14 can be easily attached between the tip of the sixth arm 10 and the hand 3. As shown in FIG. 1, when the spacer 14 is mounted, the mounting surface 12 of the hand 3 is at an angle θ with respect to the flange surface 11 at the tip of the sixth arm 10.
(Eg, 30 °). It should be noted that the spacer 14 can be easily removed in the reverse procedure.

Next, the operation of the above configuration will be described. The main body 1 of the robot configured as described above normally performs a predetermined operation such as an assembling operation in a state where the spacer 14 is not attached as shown in FIG. in this case,
The control device calculates each joint J of the arm 2 for each sampling time from the continuous locus of the position and posture of the hand 3 given in advance.
The actuators of the joints J1 to J6 are controlled while obtaining the positions and velocities of the joints 1 to J6 using an inverse Jacobian matrix.

In this type of articulated robot, however, there is a singular point where two axes are coaxially positioned and an axis positioned between the two axes performs an irregular operation. Cannot be passed by the CP operation. In this case, when the fourth joint J4 and the sixth joint J6 are coaxially positioned, there is a singular point at which the fifth joint J5 performs an irregular operation. Specifically, as shown in FIG. 2, for example, when the arm 2 is operated while keeping the hand 3 in the downward direction, the line indicated by S0 in FIG.
The joint J5 cannot pass near the singular point line S0. In the figure, the fifth joint J
The outline of the movable range of No. 5 is indicated by reference symbol E.

In the present embodiment, it has been found that the fifth joint J5 passes near the singular point line S0, for example, by actually operating the robot body 1 (or by performing an operation simulation). In this case, the singular point can be avoided by attaching the singular point changing spacer 14 between the tip of the sixth arm 10 and the hand 3 as described above.

That is, when the spacer 14 is attached between the sixth arm 10 and the hand 3, the position and the posture of the hand 3 relative to the arm 2 are changed as compared with the state where the spacer 14 is not attached. Will be done. Therefore, by attaching the spacer 14, even when the hand 3 is operated at a predetermined position and posture, the positions of the joints J1 to J6 of the arm 2 and the position of the singular point are changed. . Specifically, as shown in FIG. 1, when the arm 2 is operated in a state where the hand 3 is directed downward, for example, as in FIG. From the singular point line S0, it is greatly shifted rightward in the figure.

Thus, even if the work normally passes near the singular point line S0 as shown in FIG. 2, the position of the singular point can be made relative to the working space by attaching the spacer 14. Can be displaced,
It is possible to avoid the singular point and perform the work without stopping the arm 2 or lowering the speed. In this case, since the spacer 14 is disposed between the end of the sixth arm 10 and the hand 3 where the attachment / detachment is originally easy, it is not necessary to make a major change in the equipment. Can be easily attached and detached.

Therefore, according to the present embodiment, in the articulated robot in which the existence of a singular point cannot be avoided, the singular point is not avoided by a software method.
Since the position where the singular point occurs is changed by a mechanical method of attaching the singular point 4, the singular point can be avoided by a simple method without lowering the operation speed of the arm 2. The effect can be obtained. In this embodiment, since the spacer 14 is configured to include the inclined block 15 and the mounting surface 12 of the hand 3 is inclined with respect to the mounting flange surface 11, the position of the singular point is largely shifted. Is possible,
The singularity can be avoided more effectively.

In the above embodiment, the mounting surface 1 of the hand 3 is attached to the mounting flange surface 11 by the spacer 14.
2 is inclined, but even if the spacer is not provided with an inclination (both surfaces are parallel), the relative position of the hand 3 with respect to the arm 2 will be changed. Can be changed, and an effect of singularity avoidance can be obtained.

FIGS. 10 and 11 show another embodiment (corresponding to claim 3) of the present invention. This embodiment is different from the above embodiment in the configuration of a singular point changing spacer 31 provided between the tip of the arm 2 and the hand 3.
The spacer 31 is configured so that the mounting angle of the hand 3 with respect to the mounting flange surface 11 at the tip of the sixth arm 10 can be changed.

That is, the spacer 31 has an upper arm mounting plate 32 in the figure and a lower hand mounting plate 33 in the figure. These two plates 32, 3
3 Both have a substantially rectangular shape, and are rotatably connected by a fulcrum pin 34 at one side (rear side) in an overlapping state. Although not shown, the upper surface in the drawing of the arm mounting plate 32 is adapted to be mounted on the mounting flange surface 11 at the tip of the sixth arm 10, and the lower surface in the drawing of the hand mounting plate 33. The hand 3 (attached surface 12) is attached thereto.

The spacer 31 is located on the side (left side in the figure) of the arm mounting plate 32, and the arm mounting plate 32 and the hand mounting plate 33 are in a closed state. (See FIG. 11A) and an open state in which the hand mounting plate 33 is opened at a predetermined angle (for example, 30 °) with respect to the arm mounting plate 32 (see FIG. 11A).
(See (b)) is provided with an air cylinder 35 as a drive source (actuator). In the air cylinder 35, a bracket 36 at a base end thereof is attached to a portion near a rear end of a side of the arm attachment plate 32 by a pin 37.

On the other hand, the front end of the first link lever 38 is connected to the front end of the side of the arm mounting plate 32, and the front end of the side of the hand mounting plate 33 is The distal ends of the second link levers 39 are connected, and the base ends of both link levers 38 and 39 are connected by pins 40. At this time, the pin 40 is connected to the bracket 41 at the tip of the rod 35a of the air cylinder 35. When the rod 35a of the air cylinder 35 projects by the action of the link levers 38 and 39, the spacer 31 is opened, and when the rod 35a of the air cylinder 35 is retracted, the spacer 31 is closed. It is supposed to be.

According to the spacer 31 having the above-described structure, the position and the posture of the hand 3 relative to the arm 2 are changed between the open state and the closed state of the spacer 31. By changing
The position of the singular point can be shifted relative to the work space, and the singular point can be avoided and the work can be performed without stopping the arm 2 or lowering the speed. Therefore, similar to the above embodiment, an excellent effect that a singular point can be avoided by a simple method without lowering the operation speed of the arm 2 can be obtained.

In the spacer 31, the position of the singular point can be largely shifted by changing the angle of the hand 3, and the singular point can be avoided more effectively. Furthermore, since the angle can be automatically changed by the air cylinder 35, the singular point can be freely changed as it is once attached (without attaching / detaching). Can be used to change the open / closed state of the spacer 31 during the operation.

In the spacer 31 described above, the angle is automatically changed by the air cylinder 35. However, depending on the contents of the work, the operator manually operates the work to avoid a singular point before executing the work. A configuration in which the angle adjustment is performed may be adopted. In addition, the present invention is not limited to the embodiments described above. For example, various modifications can be considered for the configuration of the main body (arm) of the robot, the shape of the spacer, the mounting structure, and the like. The present invention can be implemented with appropriate changes without departing from the scope of the present invention.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a side view of a main body with a spacer attached.

FIG. 2 is a side view of the main body without a spacer attached.

FIG. 3 is a diagram showing a mounting flange surface at an end of an arm.

FIG. 4 is a view showing a mounting surface of a hand.

FIG. 5 is a longitudinal side view showing a spacer.

FIG. 6 is a view showing a robot mounting surface of a spacer.

FIG. 7 is a diagram showing a tool mounting surface of a spacer.

FIG. 8 is a front view (a) and a vertical side view (b) of an inclined block.
Figure showing

FIG. 9 is a diagram showing a front surface (a) and a longitudinal side surface (b) of a flange plate.

FIG. 10 shows another embodiment of the present invention, and is a perspective view of a spacer.

FIG. 11 is a perspective view showing a closed state (a) and an open state (b) of the spacer.

[Explanation of symbols]

In the drawing, 1 is a main body, 2 is an arm, 3 is a hand, 4 is a base, 5 to 10 are first to sixth arms, 11 is a mounting flange surface, 12 is a mounting surface, 14, 31 are spacers, and 15 is Inclined block, 16 is a flange plate, 17 is a robot mounting surface, 21 is a tool mounting surface, 32 is an arm mounting plate, 33 is a hand mounting plate, 35 is an air cylinder, and J1 to J6 are first to sixth joints. Show.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shuji Takeda 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Koji Ohashi 1-1-1, Showa-cho, Kariya City, Aichi Prefecture F term (reference) 3F060 AA03 BA00 CA21 DA10 EB13 EC13 FA00 FA01 FA03 HA00 HA40

Claims (3)

[Claims] 1. A multi-joint robot having a hand attached to a tip of an articulated arm, wherein a spacer for changing a singular point is attachable between the tip of the arm and the hand. Articulated robot 2. The articulated robot according to claim 1, wherein the spacer is provided so that a mounting surface of the hand is inclined with respect to a mounting flange surface at a tip of the arm. 3. The articulated robot according to claim 1, wherein the spacer is configured to change a mounting angle of the hand with respect to a mounting flange surface at a tip of the arm.