JP2001054889A - Vertical articulated robot for assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance accuracy in locus while control is being facilitated when a handle is to be linearly operated, and facilitate the avoidance of a significant point. SOLUTION: An articulated arm 13 is provided over a base 12, and a part holding hand 14 is mounted to the tip end of the arm 13, so that a robot main body 11 is formed up. The articulated arm 13 is formed out of an arm main body 15 comprising 6 axis joints (a first through a sixth joint, J1 through J6) connected together, and of a tip end arm part 16 to which the hand 14 to be connected by way of No.7 joint J7 composed of a direct acting shaft, is mounted to the tip end of the arm main body 15. A linear motor is employed as an actuator for the No.7 joint J7. A linear assembly operation by the hand 14 and the like is carried out only by the operation of the No.7 joint J7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical articulated robot for assembling, which enables an assembling operation in multiple directions by a hand attached to the tip of an articulated arm.

[0002]

As an assembling vertical articulated robot for assembling, for example, parts for automobiles, there is an assembling robot as shown in FIG. That is, the main body 1 of the robot includes a multi-joint (6-axis) arm 3 on a base 2 and a hand 4 (shown by imaginary lines) is attached to the tip of the arm 3. The arm 3
Are provided on the base 2 with the first to sixth six arms 5-1.
0 are connected via first to sixth joints J1 to J6 each formed of a turning axis or a rotation (coaxial rotation) axis. Although not shown, the first to sixth joints J1 to J6
Are respectively driven by actuators such as servo motors, and the actuators and the hand 4 are controlled by a robot controller.

[0003] Although not shown, a component supply unit for supplying components to be assembled, a conveyor mechanism for transporting a work to which the components are assembled, and the like are arranged near the robot body 1. It has become. With this,
For example, the robot body 1 is moved above the component supply unit with the hand 4 facing downward, the hand 4 is lowered to acquire (grasp) a component, and then raised, and the hand 4 is transported by a conveyor mechanism. The operation of horizontally moving the work to the upper side of the completed work, lowering the hand 4 and assembling the work with the work is repeatedly performed.

By the way, in the robot body 1 described above, there are many operations of assembling components by operating the hand 4 linearly (up and down) while maintaining a constant posture (downward) as described above. In order to operate the hand 4 linearly (CP operation) by controlling the joints J1 to J6 formed of the turning axis or the rotating axis, the control of each of the joints J1 to J6 is complicated and the trajectory accuracy is poor.

[0005] Further, in this kind of articulated robot, there is a problem of a singular point in which two axes are coaxially positioned and an axis positioned between the two axes performs an irregular operation. In the robot body 1, a singular point exists in a posture where the fourth joint J4 and the sixth joint J6 are coaxially located. For example, when the hand 4 is directed downward, a singular point line indicated by S0 in FIG. For this reason, the CP operation that passes near the singular point line S0 becomes impossible, or the operation speed is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to improve the trajectory accuracy while facilitating control of linearly operating a hand, and to avoid singularities. An object of the present invention is to provide a vertical articulated robot for assembly that can be easily performed.

[0007]

SUMMARY OF THE INVENTION The present inventor has proposed a vertical articulated robot for assembling, which enables an assembling operation from multiple directions with a hand. Focusing on the fact that it is often operated linearly in the same posture, if a linear motion shaft is provided at the tip of the articulated arm, assembly work with linear operation can be easily performed, Moreover, the present invention has been accomplished by confirming that the position of the singular point can be easily shifted by changing the relative position of the hand with respect to the arm by the linear motion axis.

That is, in the vertical articulated robot for assembly according to the first aspect of the present invention, an articulated arm is formed by connecting a five-axis or six-axis joint consisting of a turning axis or a rotating axis. It is configured by connecting a distal end arm portion to which a hand is attached to a distal end via a linear motion shaft. According to this, the hand can be operated linearly by the linear motion axis, so that it is possible to improve the trajectory accuracy while facilitating control when performing the assembling work by the linear operation, and The singularity can be easily avoided.

By the way, it is conceivable to employ a ball screw mechanism or a rack and pinion mechanism using a motor as a drive source as the actuator of the linear motion shaft. Hydraulic cylinders and the like can be used, but if a linear motor with good reverse transmission efficiency is used (the invention of claim 2), fine force control becomes possible, which is more effective.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG.
Main body 11 of vertical articulated robot for assembly according to the present embodiment
1 shows an external configuration of the apparatus. Here, the robot body 11
Is provided with a multi-joint type (in this case, 7 axes in total) arm 13 on a base 12 and a hand 14 for gripping parts is attached to the tip of the multi-joint type arm 13.
Although not shown, a controller mainly composed of a microcomputer, a teaching pendant, and the like are connected to the robot body 11.

At this time, the articulated arm 13 has an arm main part 15 composed of a pivot axis or a rotary axis and connected in this case with six axis joints, and a linear motion axis at the tip of the arm main part 15. And a distal end arm 16 to which the hand 14 is attached via an end. Hereinafter, the articulated arm 13 will be described in detail with reference to FIGS.

More specifically, as shown in FIGS. 1 and 2, the arm main portion 15 is, more specifically, a first arm 17 connected to the base 12 via a first joint J1 having a rotating shaft. A second arm 18 connected to the first arm 17 via a second joint J2 composed of a pivot axis, and a third arm 19 coupled to the second arm 18 via a third joint J3 composed of a pivot axis. A fourth arm 20 connected to the third arm 19 via a fourth joint J4 formed of a rotating shaft, and a fifth arm 21 connected to the fourth arm 20 via a fifth joint J5 formed of a turning shaft. And a sixth arm 22 connected to the fifth arm 21 via a sixth joint J6 having a rotation axis.

The distal arm 16 is connected to the sixth arm 22 via a seventh joint J7 consisting of a linear motion axis (expansion / retraction axis). At this time, as shown in FIG. 3, a linear motor 23 serving as an actuator of the seventh joint J7 is disposed in the frame of the sixth arm 22. 3 (in the vertical direction in FIG. 3), whereby the distal arm 16 is driven in a linear direction. Further, the hand 14 is provided with the distal arm 16.
Is detachably attached to a flange portion 16a provided on the distal end surface of the first member.

Although not shown, each of the joints J1 to J
Reference numerals 6 are respectively driven by actuators such as servomotors, and these actuators are controlled by the controller. The linear motor 23 is also controlled by the controller. At this time, since the reverse transmission efficiency of the linear motor 23 is high, the hand 14
The force acting on the (tip arm portion 16) is
Can be detected by the linear motor 23 based on this detection.
Is controlled, and force control of the hand 14 is performed. Further, the opening / closing operation of the hand 14 is also controlled by the controller.

Next, the operation of the above configuration will be described. Vertical articulated robot for assembly described above (Robot body 1)
Is provided, for example, on an assembly line for automobile parts to perform a part assembling operation. In this case, the robot body 11
Can move the articulated arm 13 (arm main part 15) in a complicated manner, and the hand 14 can take various positions and postures within a relatively large working range in a three-dimensional space. Multi-directional assembly work is possible.

For example, in this embodiment, a component supply unit for supplying components to be assembled, a conveyor mechanism for transporting a work to which the components are assembled, and the like are arranged near the robot body 11. And the robot body 11
Moves the hand 14 above the component supply unit with the hand 14 facing downward, lowers the hand 14 to acquire (grasp) components, then raises the hand 14, and raises the hand 14 to the workpiece conveyed by the conveyor mechanism. The operation of moving horizontally to the upper side, lowering the hand 14 to assemble the work, and then ascending the work is repeated.

In this case, when a component is obtained by the hand 14 and when the component is assembled, a linear operation in the up and down direction is performed while the hand 14 is kept in the downward state. Therefore, in the present embodiment, the operation (or a part of the operation) is performed by the arm main portion 15 (first to first).
Regardless of the operation of the sixth joints J1 to J6), the seventh joint J7
Operation, that is, the tip arm portion 16 with respect to the arm main portion 15
Is performed only by the linear operation of

Thus, the control of the articulated arm 13 (joints J1 to J7) when the hand 14 is linearly operated by the articulated arm 13 can be performed by controlling only the seventh joint J7. This is extremely easy, and at the same time, the trajectory accuracy can be improved. Further, in the present embodiment, since the linear motor 23 having good reverse transmission efficiency is adopted as the actuator of the seventh joint J7, fine force control at the time of assembling with the hand 14 can be performed. .

By the way, this kind of articulated arm 13
For the (arm main part 15), the prior art (see FIG. 4)
As described in the above, in the posture in which the fourth joint J4 and the sixth joint J6 are located coaxially, there is a problem of a singular point, and the hand 1
In the state where the same posture is maintained in 4, the CP operation of passing near the singular point becomes impossible, or the operation speed becomes slow.

On the other hand, in the present embodiment, the seventh joint J7
Can easily change the relative position of the hand 14 with respect to the arm main part 15.
4 (the tip arm portion 16) is near the sixth arm 22 (the position where the shaft 24 is immersed), and the fifth joint J5
If there is a risk that the singular point may pass near the singular point, the position of the singular point can be easily shifted by making the shaft 24 protrude by the operation of the seventh joint J7. Therefore, the singularity can be easily avoided.

As described above, according to the present embodiment, the hand 14
In the vertical articulated robot for assembly that enables assembly work from multiple directions, the work of actually finally assembling parts often requires the hand 14 to operate linearly in the same posture. Attention is paid to the distal arm portion 1 via a seventh joint J7 consisting of a direct-acting shaft at the distal end of the 6-axis arm main portion 13.
6 so that the hand 14 can be operated linearly only by driving the seventh joint J7.

This makes it easy to control the assembling work by the linear movement of the hand 14, improves the trajectory accuracy, and easily avoids singular points. Excellent effects can be obtained. Further, in this embodiment, in particular, since the linear motor 23 is employed as the actuator of the seventh joint J7, which is a linear motion axis, the linear motor 23 can be used at the time of assembling work by the hand 14, etc.
The advantage that fine force control becomes possible can also be obtained.

In the above embodiment, the linear motor 23 is used as the actuator of the seventh joint J7. However, if it is not necessary to perform fine power control, a ball screw mechanism or a rack using the motor as a driving source may be used. An & pinion mechanism or the like can be employed, and if the stroke of the linear operation can be constant, a pneumatic or hydraulic cylinder or the like can be employed. In the above embodiment, the arm main portion 15 is configured as a six-axis type.
Six axes may be combined with the linear motion axis. Others
The present invention can be implemented with appropriate modifications 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 showing an external appearance of a robot body.

FIG. 2 is a diagram showing a joint structure of a joint of a robot main body.

FIG. 3 is a diagram schematically showing a configuration of a tip arm portion.

FIG. 4 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

In the drawing, 11 is a robot body, 12 is a base, 13 is an articulated arm, 14 is a hand, 15 is an arm main part, 16
Denotes a distal arm, 23 denotes a linear motor, J1 to J6 denote joints, and J7 denotes a seventh joint (linear motion axis).

Claims (2)

[Claims] 1. An assembling vertical articulated robot which enables an assembling operation in multiple directions by a hand attached to a tip of an articulated arm, wherein the articulated arm has a turning axis or a rotating axis. And a tip arm connected to a distal end of the arm main via a direct-acting shaft and to which the hand is attached. Vertical articulated robot for assembly. 2. The vertical articulated robot according to claim 1, wherein the actuator of the linear motion shaft comprises a linear motor.