JPH1199493A - Industrial robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the extension of cycle time by providing a wrist part control means for turning any turning part of the wrist part in the direction of eliminating torsion at a preset designated angle in the where the occurrence of an operational range error is detected by a torsion detecting means. SOLUTION: In teaching, a torsion detecting part of a wrist shaft operation control part detects the occurrence of an operational range error that torsion of a tube 30 exceeds the tolerance from a rotating angle of one of a first rotating member 33, a second rotating member 34, a third rotating member 35 and a rotating part 36 of a wrist part 23. By this detection, a control main part of the wrist shaft operation control part turns the member where the operational range error occurs among the first rotating member 33, the second rotating member 34, the third rotating member and the rotating part 36 of the wrist part 23 in the direction of eliminating torsion in 360-degrees. Thus, torsion of the tube 30 can be automatically unwound to be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial robot having a linear member such as a cable or a tube between an arm and a coating tool including a coating device and a tool.

[0002]

2. Description of the Related Art In an industrial robot, cables provided at a tip of a wrist for transmitting control signals to a coating tool including a coating device and a tool, and a fluid for jetting a fluid from the coating tool. There is a case where a linear body such as a tube for transfer of the wire is provided inside or outside from the arm to the coating tool, but such a linear body is twisted due to the rotation of the wrist, and as a result, As a result, it may be damaged due to tension, interference, or the like. In order to avoid this, in the past, the operable angle range of the wrist has been greatly limited even though the operable angle range is considerably large.

[0003]

If the range of the operation angle of the wrist is largely restricted as described above, the following problems are caused by this. When performing an operation with a large operation angle of the wrist, an operation range error frequently occurs due to the restriction of the operation angle of the wrist, and the operation of the robot is interrupted. Also, in order to avoid this error, it is necessary to set the rewinding operation with a margin before reaching the operation angle end so that the wrist is always within the operation angle range, and the tact time is extended. Would. Further, in the teaching reproduction type robot, teaching must be performed including such a rewinding operation, so that the number of man-hours required for teaching is increased and the burden on the operator is increased. As a result, the stop time of the work line that is stopped during the teaching increases. On the other hand, we considered holding the linear body with a swivel mechanism or a rotary joint mechanism, etc., so as not to be affected by the rotation of the wrist, but these have a complicated structure, and in terms of cost, reliability and weight, It is disadvantageous. Therefore, an object of the present invention is to suppress the extension of the tact time without being disadvantageous in terms of cost, reliability and weight, and to reduce the man-hour required for teaching and the line stop time for teaching in a teaching-reproducing robot. It is to provide an industrial robot that can be suppressed.

[0004]

In order to achieve the above object, an industrial robot according to the present invention comprises an arm, a plurality of rotating parts, a wrist provided at a tip of the arm, and a wrist part. A coating tool provided on the opposite side to the arm, and a linear body passed from the arm to the coating tool, wherein the torsion of the linear body is within an allowable range from a rotation angle of the wrist. A torsion detecting means for detecting whether or not an operating range error exceeding the range has occurred, and, when the torsion detecting means detects that an operating range error has occurred, removing any of the rotating parts of the wrist portion from the twist. And a wrist control means for rotating a predetermined angle in a predetermined direction. Thereby, when the torsion detecting means detects that an operation range error in which the torsion of the linear body exceeds an allowable range has occurred from the rotation angle of the wrist,
The wrist control means rotates any one of the rotating parts of the wrist in a direction in which the twist is eliminated in a predetermined angle to eliminate the unwinding of the twist of the linear body.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a painting robot as one embodiment of the industrial robot of the present invention. The painting robot is connected to a manipulator 11 via a cable 12 and connected to the manipulator 11 via a cable 12. And a controller 13 connected to the controller 13 via a cable 14 for controlling the operation of the manipulator 11 and controlling data and the like.
And a hand-held operation device 15 for allowing an operator to input an input to the device.

The manipulator 11 has a fixed base 17 installed and fixed on a floor or the like, and a turning base 18 provided on the fixed base 17 so as to rotate around a first vertical axis.
A first arm 20 rotatably supported on the turning base 18 about a second horizontal axis having one end side, and a first arm 2
And a second arm 22 whose one end is rotatably supported about a horizontal third axis.
As shown in FIG. 2, a coating gun (painting tool) 25 is provided on the other end side of the device 2 via a wrist 23.

Although not shown, coating equipment such as a paint tank, a paint pump, and a paint flow meter is provided on the fixed base 17 side. The second arm 22 is provided on the second arm 22 as shown in FIG. A color changing device 28 for switching the color of the paint supplied to the coating gun 25 is attached, and the color changing device 28 is connected to the above-mentioned coating equipment via a tube (not shown).

[0008] Between the color changing device 28 attached to the second arm 22 and the coating gun 25, there are a paint supply, a paint circulation (return), a trigger air supply, a paint pattern selection air supply, and the like. A plurality of tubes (linear bodies; only one system is shown in the drawing for simplicity) 30 for supplying air for paint atomization are connected to each other. Here, tube 3
0 and the like are piped in a state of being wound around the wrist with a certain margin so that even if the wrist axis performs operations such as rotation, bending, twisting, etc. at a predetermined level, it does not break due to twisting or pulling. I have. The use of air (compressed air) for control of the coating gun, such as selection of a trigger and a coating pattern, is advantageous in terms of explosion prevention, and factory air or the like is used as this air.

The wrist portion 23 includes a first rotating member (rotating portion) 33, a second rotating member (rotating portion) 34, a third rotating member (rotating portion) 35, and a rotating member, in this order from the second arm 22 side. So-called oblique in-line type (4-roll type) in which the parts 36 are connected in series so as to be relatively rotatable.
Is adopted. As shown in FIG. 3, the first rotating member 33 is attached to the tip of the second arm 22 by the second arm 2.
The second arm 22 is rotatable about a fourth axis (θ ₄ ) coaxial with the second arm 22, and a distal end surface 33 a opposite to the second arm 22 has a cylindrical shape oblique to the axis.

The second rotating member 34 is provided with the first rotating member 3.
3 and is rotatably provided about a fifth axis (θ ₅ ) orthogonal to the center axis of the first rotating member 33 and orthogonal to the center axis of the first rotating member 33. The surface 34 a has a tip surface 33 a of the first rotating member 33 on one side.
, And the other side has a curved cylindrical shape inclined so as to be further away from the distal end surface 33 a of the first rotating member 33. The third rotating member 35, and perpendicular to the front end surface 34a of the second rotary member 34 intersects the rotational axis relative to the first rotary member 33 of the second rotary member 34 - the fifth axis (- [theta] ₅ ) Is rotatably provided, and a distal end surface 35a on the opposite side to the second rotating member 34 has
The rotating member 34 has a cylindrical shape whose base end is inclined so as to be closer to the distal end surface 34a of the rotating member 34 and the other side is further away from the distal end surface 34a of the second rotating member 34.

The rotating section 36 is rotated about a sixth axis (θ ₆ ) orthogonal to the distal end surface 35 a of the third rotating member 35 and obliquely intersecting the rotation axis of the third rotating member 35 with respect to the second rotating member 34.
Is provided rotatably. The rotation axis of the first rotation member 33 with respect to the second arm 22 and the first rotation member 3
The angle formed by the second rotating member 34 with respect to the rotation axis with respect to 3 is
The angle is the same as the angle between the rotation axis of the third rotation member 35 with respect to the second rotation member 34 and the rotation axis of the rotation unit 36 with respect to the third rotation member 35.

As described above, the rotation unit 36 is controlled by the rotation angles of the second rotation member 34 and the third rotation member 35.
For example, the posture and the position are changed such that the center axis is made coincident with the center axis of the second arm 22 or the center axis is inclined so as to form an acute angle with the center axis of the second arm 22. As a result, the attitude and position of the coating gun 25 attached to the rotating unit 36 are also changed.

In the manipulator 11, a fixed base 1 is provided.
7, the rotation of the first arm 20 with respect to the rotation base 18, the rotation of the second arm 22 with respect to the first arm 20, the rotation of the first rotation member 33 with respect to the second arm 22, the first rotation member. A servo motor (not shown) for driving the rotation of the second rotation member 34 with respect to the rotation member 33 and the rotation of the rotation portion 36 with respect to the third rotation member 35 and an encoder for detecting each rotation angle are incorporated. The controller 13 performs the painting operation by operating the manipulator 11 while grasping the position of the painting gun 25 and the attitude of the manipulator 11 based on the signals from these encoders.

As shown in FIG. 4, the controller 13
ROM 40 that stores a program indicating an operation procedure and the like and fixed data and the like, and RAM 41 that is backed up by a battery and stores the operation result, teaching data, and the like
A timer 42 that generates a sampling time; a trajectory control unit 43 that generates an operation trajectory of the coating gun 28 and an operation command value of the manipulator 11 from the position of the coating gun 28 and the attitude of the manipulator 11; and a wrist axis (θ ₄ , theta _5, the wrist axis operation control unit 44 is controlled to conform to the same posture while within its operating range the operation angle of theta _6), the servo motor driver 45 described later from the operational command value generated by the orbit control unit 43 And a servo motor driver 45 for operating a servo motor in accordance with an operation command signal from the servo control unit 46.
And a control arithmetic unit 47.

Although not shown, the wrist axis operation control unit 44 detects, from the rotation angle of the wrist unit 23, whether or not an operation range error in which the torsion of the tube 30 exceeds an allowable range has occurred. A first rotation member 33 and a second rotation member 3 of the wrist 23 when an operation range error is detected by the torsion detection unit.
4. Either the third rotating member 35 or the rotating portion 36 is rotated at a predetermined angle (in this case, 3
60 °) and a control main body (wrist control means) for rotating.

The torsion detecting section is provided for each wrist axis (θ
₄ , θ ₅ , and θ ₆ ), the operating angle range is set according to the length of the tube 30. If the operating angle range is exceeded, an operating range error in which the torsion of the tube 30 exceeds the allowable range occurs. The operation range error flag is set and an alarm (at least one of a sound and a display) is generated by a not-shown notifying means. If the operation range error flag is within the operation angle range, the tube 30 is twisted. It is determined that there is no operating range error within the allowable range, the operating range error flag is reset, and no alarm is issued by the notification means. Note that this alarm is released by a release operation to the hand operation device 15.

Here, for example, when the wrist axes (θ ₄ , θ ₅ , θ ₆ ) have an operation angle range of ± 360 °, the torsion detection unit performs the operation during the operation teaching of the manipulator 11. For example, when the fourth axis (θ ₄ ), that is, the first rotating member 33 moves →→ as shown in FIG. 5 and exceeds 360 °, it is detected that an operating range error has occurred.

Then, the control main body includes the manipulator 1
During the teaching of the first operation, the control cycle shown in the flowchart of FIG. 6 is executed for each wrist axis (θ ₄ , θ ₅ , θ ₆ ) at every preset sampling time. That is, it is determined whether or not an operating range error has occurred by checking the operating range error flag (step S).
1) If the operation range error flag has not been set, this control cycle is ended. If the operation range error flag has been set, the following sequence is executed.

First, it is determined whether or not the operator has issued an instruction to operate the manipulator 11 with the hand operation device 15 (step S2).
Is not issued, it is determined whether or not a predetermined time (for example, 5 seconds) has elapsed since the alarm was released by the hand operation device 15 (step S3). If not, the control cycle ends. Here, "wait" for this fixed time
This allows the operator to have time to perform the next operation, such as teaching the point immediately before the operation range error, and automatically determines whether or not to perform the axis return operation described later. This is because the determination is made based on the passage of time. The predetermined time may be arbitrarily set by the hand operation device 15, or the type of the work or the coating gun may be detected and automatically set according to the detected type.

If it is determined in step S3 that the predetermined time has elapsed, an axis returning operation of returning the axis in which the error has occurred by 360 ° (rotating in a direction to eliminate the twist) is performed. That is, whether the axis return operation has reached the end of the axis return operation,
In other words, it is determined whether the 360 ° axis has already been returned (step S4). If the axis return operation has not reached the end, it is next determined whether the axis return operation has been started (step S5). . If the axis return operation has not been started in step S5, the axis return operation, that is, the operation of returning the axis in which the error has occurred by 360 ° with the servo motor is started (step S6), while the axis return operation has been started. Ends this control cycle.

Here, as described above, for example, as shown in FIG. 5, the fourth axis (θ ₄ ), that is, the first rotating member 33 operates →→ to 360 °, and the operating range error flag is set. In the case, the fourth axis (θ
₄ ) That is, the first rotating member 33 is operated in the direction opposite to the direction of 360 °. When performing the axis return operation, the control main unit sets the corresponding wrist axis to, for example, 10 ° / s.
The servo motor is controlled so as to operate at ec. The speed of this return operation may be arbitrarily set by the hand operation device 15, and the type of the work or the coating gun is detected and the speed is adjusted accordingly. May be set automatically. In addition, the control main unit causes the alarm generating device to generate an alarm (at least one of a sound and a display) notifying that the operation is the axis return operation during the operation.

In step S2, if the operator has issued an instruction to operate the manipulator 11 with the hand operation device 15, and if the end of the axis return operation has been reached in step S4, it is determined whether or not the axis return operation is in progress. (Step S7), when it is determined that the axis return operation is being performed, the axis return operation is stopped (Step S7).
8). Then, after stopping the axis return operation in step S8 and when it is determined in step S7 that the axis return operation is not being performed, the operation range error flag is reset (step S9), and the control cycle ends. After resetting the operating range error flag, nothing is done until an operating range error occurs again.

According to the above-described embodiment, at the time of teaching, the torsion detecting unit of the wrist axis operation control unit 44 is configured to control the first rotating member 33, the second rotating member 34, and the third rotating member 34 of the wrist 23. When it is detected that an operation range error in which the twist of the tube 30 exceeds the allowable range has occurred from any of the rotation angles of the rotation member 35 and the rotation unit 36, the control main unit of the wrist axis operation control unit 44 First rotating member 3
3. Rotate the second rotating member 34, the third rotating member 35, and the rotating portion 36, in which the operating range error has occurred, by 360 ° in the direction in which the torsion is eliminated, and automatically cancel the unwinding of the torsion of the tube 30. Will be.

Therefore, since it is not necessary to perform the teaching including the rewinding operation, the man-hour required for the teaching is not increased, the burden on the operator is reduced, and the stop time of the work line for the teaching can be suppressed. As a result, the inconvenience caused by the operator's operation error can be reduced. Moreover, since no swivel mechanism or rotary joint mechanism is used, it is advantageous in terms of cost, reliability, and weight.
In addition, since the tube 30 is rotated by 360 °, the wrist 23 can be returned to the original posture after the twist of the tube 30 is eliminated.

In the above embodiment, since the teaching-reproduction-type industrial robot is used, the effect is obtained at the time of teaching. However, the present invention can be applied to other than the teaching-reproduction type. Since there is no need to set the rewind operation with a margin before reaching the end of the operation angle, it is possible to suppress the extension of the tact time.

In the above embodiment, the wrist
Each wrist axis (θ_Four, Θ_Five, −θ _Five, Θ₆) Each
The operation angle range is set for
If the angle range is exceeded, the twist of the tube 30 will exceed the allowable range.
To detect that an operating range error has occurred
As an example, the oblique inline type (4
In the case of (roll type), it is necessary to limit the operation angle for each axis.
And the “fourth axis operating angle” representing the actual twist of the tube 30.
It is also possible to limit by "degree-sixth axis operation angle". This
In the case of, the torsion detection unit calculates “4th axis operation angle−6th axis operation
Angle ”is a preset operation angle range (for example, ± 360
Set the operation range error flag when exceeding (ii)
Will be.

Similarly, when a wrist of a type in which the actual torsion of the tube is expressed by the sum of the fourth axis operation angle, the fifth axis operation angle, and the sixth axis operation angle is used, the above-mentioned sum is used. It is possible to limit. In these cases, when an operation range error occurs in the wrist axis, the axis return operation may be performed on any axis. For example, the axis return operation may be performed by always rotating the sixth axis. Thus, if the sixth axis is always rotated to perform the axis return operation, the operation for returning the wrist 23 to the axis can be minimized. Note that the sequence at this time may be the same as in the above embodiment.

[0028]

As described above in detail, according to the industrial robot of the present invention, the torsion detecting means generates an operation range error in which the torsion of the linear body exceeds an allowable range from the rotation angle of the wrist. Is detected, the wrist control means rotates one of the rotating parts of the wrist in a direction in which the twist is eliminated by a predetermined angle, thereby canceling the unwinding of the linear body. Therefore, there is no need to set the rewind operation with a margin before reaching the end of the operation angle, so that it is possible to suppress an increase in the tact time. Further, in the teaching reproduction type robot, since it is not necessary to perform the teaching including the rewinding operation, the man-hour required for the teaching is not increased, the burden on the operator is reduced, and the stop time of the working line for the teaching is reduced. Can be suppressed. Moreover, since no swivel mechanism or rotary joint mechanism is used, it is advantageous in terms of cost, reliability, and weight.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of an industrial robot of the present invention.

FIG. 2 is a side view showing the vicinity of a wrist of the industrial robot according to one embodiment of the present invention.

FIG. 3 is a side view showing the vicinity of a wrist and a wrist axis of the industrial robot according to one embodiment of the present invention.

FIG. 4 is a block diagram illustrating a controller according to an embodiment of the industrial robot of the present invention.

FIG. 5 is a diagram showing a rotation operation of a fourth axis of the industrial robot according to one embodiment of the present invention.

FIG. 6 is a flowchart showing control contents of a controller of the industrial robot according to one embodiment of the present invention.

[Explanation of symbols]

22 second arm 23 wrist 25 coating gun (painting tool) 30 tube (linear body) 33 first rotating member (rotating portion) 34 second rotating member (rotating portion) 35 third rotating member (rotating portion) ) 36 rotating unit 44 wrist axis operation control unit (twist detection means, wrist control means)

Claims (1)

[Claims] An arm, a plurality of rotating parts, a wrist provided at a tip of the arm, a coating tool provided on an opposite side of the arm of the wrist, and a coating tool provided from the arm. An industrial robot having a linear body passed to the torsion detecting means for detecting whether or not an operation range error in which the torsion of the linear body exceeds an allowable range has occurred from the rotation angle of the wrist, Wrist control means for rotating any of the rotating parts of the wrist when the torsion detecting means detects that an operation range error has occurred, by a predetermined angle set in a direction in which torsion is eliminated. An industrial robot characterized by becoming.