JP2734868B2 - Position accuracy inspection device for multi-axis robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position accuracy checking device, and more particularly to a position accuracy checking device for checking the position accuracy of a multi-axis robot having a hand for holding a workpiece.

[0002]

2. Description of the Related Art FMS (Flexible Manufacturing System)
In a factory automation system such as m), a group of several or dozens of NC machine tools are connected by an automatic transfer device that carries a workpiece or a tool. These NC machine tools and automatic transfer devices are managed by a computer, and various types of workpieces are processed one after another according to a production plan according to a command from the computer.

As an automatic transfer device used for this type of FMS, there is known an automatic transfer device in which a multi-axis robot is movably arranged on a line. A multi-axis robot has a high degree of freedom in space and is suitable for positioning a work in various postures. When using a multi-axis robot for an automatic transfer device,
It is important to eliminate the displacement at the load position.
Possible causes of the misalignment of the multi-axis robot include mechanical bending and misalignment of the hand and the robot arm, play and wear of the drive system, and misalignment of a feedback unit such as an encoder used for position detection. Conventionally, in order to check the positional deviation, a fixed dial gauge is installed at a reference position, the multi-axis robot is moved to a measurement position by an inspection program, and the repetition accuracy at that time is measured.

[0004]

In the above-mentioned conventional configuration,
With the multi-axis robot moved to the measurement position, the operator must read the value of the dial gauge, and the operator must enter the movable area of the robot. Since a multi-axis robot may malfunction due to the influence of noise or the like, it is dangerous that an operator enters the movable area of the robot.

Further, since the operator must read the measured value of the dial gauge, the position accuracy of the multi-axis robot cannot be determined easily and accurately. SUMMARY OF THE INVENTION An object of the present invention is to enable easy, safe and accurate inspection of the position accuracy of a multi-axis robot.

[0006]

According to a first aspect of the present invention, there is provided an apparatus for inspecting the position accuracy of a multi-axis robot having a hand for holding a workpiece. There is provided a mode setting unit, a moving unit, a detecting unit, a determining unit, and a displaying unit. The mode setting means interlocks with the operation of the multi-axis robot.
It is a means to set the interlock mode to check the accuracy.
You. For the moving means , the linked mode is set by the mode setting means.
When it is determined, the hand is moved along each of the X, Y, and Z axis directions to be arranged at the reference position in each axis direction. Detection hand
If the interlock mode is not set by the mode setting means
Of the multi-axis robot operated manually
Detects the reference work held in. The judgment means is linked
When the mode is set, a reference work held by the hand is detected at each reference position, and it is determined whether or not the detected position is within a preset tolerance. The display means displays a result of the determination by the determination means. The position accuracy inspection device for a multi-axis robot according to claim 2 is the reference work according to claim 1.
Is a columnar workpiece, and the moving means is the reference workpiece.
At the axial reference position and the radial reference position for each axis.
Place.

[0007]

In the position accuracy checking device for a multi-axis robot according to the present invention, a mode setting hand is used for checking the position accuracy of the hand.
When the interlock mode is set by the step, the moving means moves the hand along the X, Y, and Z axis directions and arranges the hands at reference positions in the respective axis directions. When the hand moves to the reference position, the determining means detects the position of the reference work held by the hand at each reference position, and determines whether the detected position is within a preset tolerance. Then, the determination result is displayed by the display means. On the other hand, mode setting means
If the interlock mode is not set by
The detecting means detects the position of the hand that has been moved. At this time,
If the author operates the multi-axis of the multi-axis robot for each axis, one axis
You can check the accuracy of each.

Therefore, the operator can safely check the position accuracy without approaching the multi-axis robot.
Since the judgment result is displayed, it can be checked at a glance whether the detected position is within a preset tolerance, and the position accuracy can be checked accurately and easily.

[0009]

FIG. 1 shows a factory automation line employing one embodiment of the present invention. The factory automation line is composed of a six-axis multi-axis robot 2 running on a rail 1 laid along the line, a temporary table and NC machine tools arranged on both sides of the rail 1.

A setter 3 for setting a work at a reference position and a position accuracy checking device 4 for checking the position accuracy of the multi-axis robot 2 are arranged on both sides upstream of the line. A robot controller 5 for controlling the multi-axis robot 2 and an inspection controller 6 for controlling the position accuracy inspection device 4 are arranged on the upstream side (upper side in FIG. 1) of the setter 3. On the downstream side of the setter 3, a temporary placing table 7, NC lathes 8, 9 and a temporary placing table 10 are arranged in order from the upstream side to the downstream side. In addition, on the downstream side of the position accuracy inspection device 4, in order from the upstream side to the downstream side, the temporary placing table 11, the machining center 12, the temporary placing table 1
3. The gun drill machine 14 and the temporary placing table 15 are arranged. Here, when the material work is formed in a cylindrical shape, the setter 3 is set so that the axis of the work is along the Z-axis direction orthogonal to the paper surface. In addition, temporary stand 7,10,
11, NC lathes 8, 9 and machining center 12,
The work is set so that the axis of the work is along the X-axis direction along the line direction, and is set along the Y-axis direction orthogonal to the X-axis direction in the temporary placing tables 13, 15 and the gun drill machine 14.

The robot controller 5 and the inspection controller 6 are installed outside the operation area of the multi-axis robot 2. For this reason, when the operator operates these controllers 5 and 6, even if the multi-axis robot 2 malfunctions, there is no fear of causing harm to the operator. The multi-axis robot 2 is installed on a traveling carriage 21 as shown in FIG. The traveling vehicle 21 is configured to run on the rail 1 in the X-axis direction. The multi-axis robot 2
The end has a rotatable hand 22. The hand 22 is detachable and is exchanged depending on the type of work. The position accuracy checking device 4 includes a mounting bracket 23 erected on the floor, and three signal locators 24 _x , 24 _y , provided at the tip of the mounting bracket 23.
24 _z . Each signal locator is the X-axis direction, the Y-axis direction,
This is to check the positional accuracy of the shaft. Each of the signal locators 24 _x , 24 _y , and 24 _z has a configuration in which a tolerance can be set for the dial gauge.
It is possible to output a judgment signal OK when the value is within the tolerance, a judgment signal −NG when the value is outside the negative side of the tolerance, and a judgment signal + NG when the value is outside the positive side of the tolerance. I have.

Note that this tolerance can be set according to the shape of the work and the like. For example, when the maximum effective tolerance is ± 1 mm, the safety factor is set to 30%, and the tolerance is set to ± 0.3 mm. As shown in FIG. 3, the robot controller 5 includes a robot controller 30 using a microcomputer.
It has. The robot controller 30 includes a memory 31,
Other input / output units such as a robot main body 32, a CRT 33, and a keyboard are connected. The memory 31 stores various operation programs for operating the multi-axis robot 2.

The inspection controller 6 has an accuracy inspection control unit 40 composed of a microcomputer. The accuracy check control unit 40 and the robot control unit 30 are connected. The accuracy check controller 40 includes the signal locator 24
_x, and 24 _y, 24 selecting unit 43 for selecting one of _z, the selection display unit 44 for displaying the determination signal of the selected signal high applicator, to list the result of the determination in the axial direction Display unit 45 is connected. The display unit 45 displays OK, + NG,
-Three LED lamps of NG are provided. The selection unit 43 and the selection display unit 44 are connected to each other.

A data memory 41, an interlock switch 42, and other input / output units are connected to the accuracy check control unit 40. The data of the determination result is stored in the data memory 41. Here, each signal locator checks the position accuracy in two selected directions, axial and radial, on each axis. Therefore, the determination data of the positional accuracy in all six directions is stored in the data memory 41. The interlock switch 42 is automatically interlocked to check the accuracy in conjunction with a multi-axis robot 2 and the positional accuracy checking device 4
This switch is turned on when setting the mode .

Next, an outline of the inspection operation will be described.
When the multi-axis robot 2 and the position accuracy inspection device 4 operate in conjunction with each other by operating the interlock switch 42, the hand 22 of the robot 2 grips the reference work 25 for accuracy inspection as shown in FIG. . In this state, the robot first moves to the measurement position in the X-axis direction, and then rotates the hand by 90 ° to move to the measurement position in the radial direction. Thereby, the positional deviation in the axial direction and the radial direction in the X-axis direction is determined. Subsequently, the displacements in the axial direction and the radial direction in the Y-axis direction and the Z-axis direction are similarly determined, respectively. Then, these determination results are displayed on the display unit 45.

Next, the details of the control operation will be described with reference to FIGS.
This will be described based on the control flowchart shown in FIG. In the robot controller 5, first, in step S1, initialization such as moving the multi-axis robot 2 to an initial position is performed. In step S2, a teaching instruction from the operator is received. In step S3, an automatic start command from the operator is received. If automatic startup is not accepted in step S3, the process proceeds to step S4. In step S4, the operation of the robot 2 is performed manually. When this ends, the process returns to the step S2.

When a teaching command is received in step S2, the process proceeds to step S5. In step S5, a teaching process is performed. This teaching process
For example, the hand 22 of the robot 2 during the accuracy check
This is performed in order to memorize the trajectory of the movement. If the automatic startup is accepted in step S3, step S3
Move to 6. In step S6, the operation program stored in the memory 31 is read. Here, when a plurality of operation programs are stored in the memory 31, the operation program selected by the operator is read.
In step S7, it is determined whether or not the operation program is an inspection process. In step S8, it is determined whether or not the program is another program. If it is determined in step S7 that the program is the inspection program, the process proceeds to step S9. Also,
If it is determined in step S8 that the program is another program, the process proceeds to step S10. In step S10, the designated program is processed, and the process returns to step S2.

In the inspection process in step S9, as shown in FIG. 6, first, in step S11, an inspection start signal is turned on and this is output to the inspection controller 6. When the inspection start signal is turned on, the robot controller 5 displays "under inspection" on the CRT 33, for example. In step S12, a selection signal is output to the inspection controller 6. Here, the selection signal is a signal for selecting each axis and its inspection direction, and outputs any one of a total of six different selection signals in the axial direction and the radial direction for each of X, Y and Z axes. Is done. In step S13, the hand 22 is moved to a measurement position according to the output selection signal. In step S14, it is determined whether the reference work 25 held by the hand 22 has reached the measurement position in the selected direction. The movement of the robot 2 is continued until the reference work 25 reaches the measurement position. When the reference work 25 reaches the measurement position, the process proceeds to step S15.

In step S15, a measurement strobe signal is output to the inspection controller 6. In step S16, an inspection completion signal in the selected direction from the inspection controller 6 is waited. Upon completion of the inspection in the selected direction, the flow shifts to step S17. In step S17, the robot 2 is moved to a standby position during the inspection processing. In step S18, it is determined whether inspections in all directions have been completed. This determination is made based on an inspection completion signal from the inspection controller 6. Until the inspection in all the selected directions is completed, the process returns to step S12, and the inspection in the next selected direction is performed. When the inspection in all directions is completed, the process proceeds to step S19.
In step S19, the inspection start signal is turned off. When the inspection start signal is turned off, the process returns to the main routine.

On the other hand, in the inspection controller 6, first, as shown in FIG. 7, initialization such as clearing the contents of the data memory 41 is performed in step S21. Step S22
Then, it is determined whether or not the interlocking switch 42 for setting the interlocking mode is turned on . Interlock switch 42 is turned on and interlocked
If the mode has been set , the process moves to step S23. In step S23, the robot controller 5
It is determined whether or not the inspection start signal is output from.
If the inspection start signal has been output, step S24
Move to In steps S24 to S29, the process waits until the robot controller 5 outputs a selection signal in each selection direction.

If no selection signal has been output, the process proceeds to step S30. Steps S30 to S
At 35, it is determined whether the inspection in each selected direction has been completed. If the respective inspections have not been completed, the process returns from step S30 to S35 to step S24. If it has been completed, the process proceeds from step S35 to step S36.
Move to In step S36, an inspection completion flag is set. When this flag is set, an inspection completion signal is output to the robot controller 5. The robot controller 5 detects this in step S18 in FIG. In step S37, the inspection result is set, and the inspection result is displayed on the display unit 45. Step S38
Then, the operator looks at the inspection start signal of the robot controller 35 and determines whether or not it is on.

If the inspection start signal has already been turned off, the flow shifts to step S39. If the inspection start signal is on, the process returns to step S36, and outputs an inspection completion signal to the robot controller 35. In the step S39, it is determined whether or not the reset has been performed by the operator. If reset has been applied, step S4
0, and if no reset has been applied,
The process returns to step S22. In step S40, the inspection result is reset, and the contents of the data memory 41 are reset. By providing the judgment step of step S39, even if the inspection is completed, the inspection result is held until the reset is performed. In step S41, the inspection completion flag is reset. When these processes are completed, the linked mode
The inspection operation using the command is terminated.

[0023] In the event <br/> if the interlocking switch 42 has not been set, the program proceeds from step S22 to step S43. In step S43, a subroutine SUB0 is executed. This SUB0 is for each axis, the signal high applicator 24 _x, 24 _y, 24 precisely have rows a set of measurement positions _z
And an inspection mode line Utame, move the multi-axis robot 2 by hand, for use in performing measurement position settings for each axis. Here, as shown in FIG. 10, first, in step S51, it is determined whether or not the X axis has been selected. In step S52, it is determined whether the Y axis has been selected. In step S53, it is determined whether the Z axis has been selected. The selection of each axis is performed by an operator's key operation or the like.

If it is determined in step S51 that the X-axis has been selected, the process proceeds to step S54. In step S54, a signal locator X-axis selection flag is set.
Thereby, the selection unit 43 sets the signal locator 24 _x
And outputs it to the selection display section 44. In step S55, the signal locator Y-axis selection flag is reset. In step S56, the signal locator Z-axis selection flag is reset. When these processes are completed, the process returns to the main routine.

Similarly, when the Y axis is selected in step S52, the signal locator Y axis selection flag is set in step S57, and in steps S58 and S59,
The X-axis and Z-axis selection flags are reset. If the Z-axis is selected in step S53, the process proceeds to step S53.
At 60, the Z-axis selection flag is set, and at steps S61 and S62, the X-axis and Y-axis selection flags are reset, respectively. Further, when the Z axis is not selected in step S53, the process proceeds to step S63. Step S
In 63 to S65, all the selection flags are reset.

If no inspection start signal has been sent from the robot controller 5, step S23 in FIG.
Then, the process shifts to step S37 in FIG. 9 to set an inspection result. This means that until the next inspection start signal is output,
This is to hold the result of the inspection performed immediately before. On the other hand, when the inspection start signal is received and further the X-axis direction selection signal is received, the process proceeds from step S24 to step S44. In step S44, the X-axis
A subroutine SUB1 for performing a direction checking operation is executed. In SUB1, as shown in FIG. 11, first, in step S72, the signal locator X-axis selection flag is set. In step S73, the Y-axis selection flag is reset. In step S74, the Z-axis selection flag is reset. Thus, the selector 43 selects the determination signal of the signal high applicator 24 _x.

In step S75, the control waits for the transmission of a measurement strobe signal from the robot controller 5. Upon receiving the measurement strobe signal, the process proceeds to step S76.
In step S76, it is determined whether the determination signal OK from the signal high applicator 24 _x outputted. If the determination signal OK has been output, the flow shifts to step S77.
In step S77, an X-axis direction inspection OK flag is set. In step S78, an X-axis direction inspection completion signal is set. In response, the robot controller 5
Then, it is determined in step S16 in FIG. 6 that the inspection in the selected direction is completed. In step S79, the signal locator X-axis selection flag is reset. Upon completion of the process in the step S79, the process returns to the main routine.

If the determination signal OK has not been output, the process proceeds from step S76 to step S80. In step S80, it is determined whether a determination signal -NG has been output. If it is determined that the determination signal -NG has been output, the flow shifts to step S81. In step S81, the X-axis direction inspection-NG flag is set, and the routine goes to step S78. If it is determined in step S80 that the determination signal -NG has not been output, the process proceeds to step S82.
Move to In step S82, it is determined whether a determination signal + NG has been output. If it is determined that the determination signal + NG has been output, the flow shifts to step S83. In step S83, the X-axis axis direction inspection + NG flag is set, and the routine goes to step S78. Also, the judgment signal + NG
If it is determined that is not output, the process moves to step S84. In step S84, the X-axis axis direction inspection impossible flag is set, and the routine goes to step S78.

As described above, by setting the respective flags, the inspection result is set in step S37 in FIG. 9, and the inspection result is displayed. Also, SUB2 to SU
Inspection processing in the interlocking mode in B6 is only the setting and resetting of the selection flag for each axis and the contents of the inspection flag differ depending on the selected axis, or in the axial direction or in the radial direction. This is the same as the processing of SUB1.

When the inspection result is set in this way, a list of inspection results is displayed on the display unit 45 by turning on and off the LED lamp, as described above. Here, the position accuracy is checked in the basic posture when setting the work on the line, and the check result is displayed on the display unit 45. Therefore, the work can be easily performed in all directions when the work is loaded on the line. In addition, the position accuracy can be checked safely.

This check is performed, for example, once a month.
When an abnormality is found by the inspection, for example, a detailed inspection is separately performed, a cause of the abnormal part is pursued, and a measure is taken according to the cause.

[0032]

As described above, in the position accuracy inspection apparatus of the present invention, the hand of the multi-axis robot is moved to the reference positions of a plurality of axes, and at each reference position, the position of the reference work held by the hand is detected. Then, it is determined whether or not the detected position is within a preset tolerance and the determination result is displayed, so that the accuracy of the multi-axis robot can be checked safely, easily and accurately.

[Brief description of the drawings]

FIG. 1 is a plan view of a factory automation line employing one embodiment of the present invention.

FIG. 2 is a perspective partial view of a factory automation line.

FIG. 3 is a control block diagram of the accuracy checking device.

FIG. 4 is a diagram showing an outline of an accuracy check.

FIG. 5 is a control flowchart of the multi-axis robot.

FIG. 6 is a control flowchart of an inspection process of the multi-axis robot.

FIG. 7 is a control flowchart of the position accuracy checking device.

FIG. 8 is a control flowchart of the position accuracy checking device.

FIG. 9 is a control flowchart of the position accuracy checking device.

FIG. 10 is a control flowchart showing processing contents of SUB0.

FIG. 11 is a control flowchart showing processing contents of SUB1.

[Explanation of symbols]

2 Multi-axis robot 4 Position accuracy inspection device 5 Robot controller 6 Inspection controller 22 Hand 24 _x , 24 _y , 24 _z signal locator 25 Reference work 30 Robot controller 40 Accuracy inspection controller 45 Display

Claims (2)

(57) [Claims] An apparatus for checking the positional accuracy of a hand of a multi-axis robot having a hand for holding a workpiece, wherein the position accuracy of the hand is checked in conjunction with the operation of the multi-axis robot. Interlock to check accuracy
A mode setting means for setting a mode, and an interlock mode set by the mode setting means.
Can, moving means for placing the hand the X, Y, the moving respectively along the Z-axis direction reference position of each axis direction, not linked mode is set by said mode setting means
Of the multi-axis robot operated manually
Detecting means for detecting a reference work held by the hand, and detecting the reference work held by the hand at each of the reference positions when the interlocking mode is set , and detecting the position within a preset tolerance. And a display unit for displaying a result of the determination by the determining unit. 2. The method according to claim 1, wherein the reference work is a columnar work, and the moving unit moves the reference work in an axial direction for each axis.
The position accuracy inspection device for a multi-axis robot according to claim 1, wherein the position accuracy inspection device is arranged at a reference position and a reference position in a radial direction .