JPH033544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for an industrial robot that is shared by a plurality of processing lines.

In general, industrial robots immediately stop processing work in the event of an abnormal protrusion on the workpiece, a collision between the processing tool and the workpiece due to a teaching error (i.e., forgetting to teach the welding point), or other malfunctions on the processing line. There is.

However, if an industrial robot is shared by multiple processing lines and performs processing work in sequence, if an abnormality like the one described above occurs on one processing line, all processing lines will stop working, resulting in production This results in a drastic decline in ability.

In view of the above-mentioned circumstances, the present invention sets a reference point to which the processing tool of an industrial robot returns every time the processing work in each processing line is completed, and the control means is configured to control the point when an abnormality occurs in relation to the processing line and/or the workpiece. Any abnormality in this processing line is registered, and each time the processing tool returns to the reference point, it is determined whether or not there is an abnormality registered in the processing line on which processing work should be started, and if an abnormality is registered, the processing line is skipped. The robot is characterized in that it commands the robot to move to the next processing line, so that even if there is an abnormality in one processing line, it does not affect the work of other processing lines, and production efficiency due to abnormal situations is improved. The purpose of the present invention is to provide a control method for an industrial robot that is shared by multiple processing lines, with the aim of minimizing the decline in performance.

Prior to a specific explanation of the present invention, a processing line and a welding robot as an industrial robot, which are the background of the present invention, will be explained.

In Fig. 1, 1, 2, and 3 are rectangular loop-shaped processing lines (hereinafter referred to as lines 1, 2, and 3), each consisting of a roller conveyor.
The corners where the two lines 1, 2, and 3 approach are set as processing stations 1a, 2a, and 3a, respectively, and multiple workpieces 4, 5, and 6 are intermittently circulated along the lines 1, 2, and 3, respectively. It was designed to be transported. In each line 1, 2, and 3, when the roller conveyor stops intermittently, unwelded workpieces are automatically or manually transferred to a workpiece loading location (not shown) set downstream from the processing stations 1a, 2a, and 3a in the transport direction. W1, W2, and W3 are mounted on the pallets 4, 5, and 6, respectively, and are sequentially moved to each processing station 1a, 3a by an articulated welding robot 7 installed on the floor at a midpoint between the processing stations 1a, 2a, and 3a. Works W loaded on pallets 4, 5, and 6 placed on 2a and 3a
1, W2, and W3 are automatically welded, and the welded workpieces W1, W2, and W3 are transferred to pallets 4 and 4 at a workpiece unloading location (not shown) set downstream in the transport direction from processing stations 1a, 2a, and 3a, respectively.
The empty pallets 4, 5, 6 are returned to the work loading place.

Reference numerals 8, 9, and 10 indicate locking devices consisting of air cylinders installed in the processing stations 1a, 2a, and 3a, respectively. The pallets are fitted and engaged with each other to position and fix each pallet. Each of the locking devices 8, 9, and 10 also has a pallet presence/absence detector (not shown) that detects when the pallets 4, 5, and 6 are in contact with each other.
Equipped with:

The multi-jointed welding robot 7 has a welding torch 11 (hereinafter referred to as a torch 11) as a processing tool on the final control axis.
). 12 is the torch 11
14 is a control means with a built-in microcomputer that comprehensively controls the lines 1, 2, 3, the welding robot 7, the power supply 12, etc.; 1
5 is a remote control panel derived from the control means 14, which can remotely control the movement and operation of each part by manual operation,
A teaching operation is performed on W3 to input a user program into a memory (not shown) within the control means 14.

FIG. 2 is a schematic explanatory diagram mainly showing a circuit block diagram of the power supply device 12. As shown in FIG. 16 and 17 are electrode supply rolls attached to the power supply device 12;
With a pair of power supply rollers, the electrode 13 is pulled out from the supply roll 16 by the rotation of the feed roller 17 and fed to the torch 11 through the flexible tube 18, and the tip protruding from the torch 11 is welded. It becomes a point. Reference numerals 19 and 20 denote voltage applying means and energization state detecting means built into the power supply device 12. Of these, the voltage applying means 19 includes a welding power source 19a, a sensor power source 19b, an abnormal approach detection power source 19c, and one end connected to the electrode 13. A changeover switch 19d is connected to selectively connect to either the welding power source 19a or the sensor power source 19b at the appropriate time, and the jacket 11a is made of the conductor of the torch 11 at one end (however, the jacket 11a is not electrically connected to the electrode 13). a normally open open/close switch 19c that is connected to a power source 19c for detecting abnormality at a timely manner.
Consists of etc.

The energization state detection means 20 has one end connected to the sensor power source 19b and the abnormal approach detection power source 19c, and the other end connected to the welding power source 19c.
Detection of energization status for sensors and abnormal approach detection connected to each processing station 1a, 2a, 3a which is electrically connected to workpieces W1, W2, W3 through each pallet 4, 5, 6 together with the reverse changeover switch 19d side of 9a. Sensor and abnormal approach detection circuits 20a, 20b and respective energization state detection circuits 20a, 20b, in which changes in the energization state (current, voltage, or changes in both) are input as detection signals and transmitted to the control means 14. and energization state detection output circuits 20c and 20d.

At the time of sensing, the electrode 13 protruding from the torch 11 is used as a sensor to find the welding line of each workpiece W1, W2, W3, and at the time of teaching, the posture, movement speed, welding conditions, etc. of the torch 11 are carried out according to the program obtained by the teaching. During tests to confirm the
Always close the open/close switch 19e and apply a detection voltage (this is a high voltage, low current at the same level as the sensor voltage) to the jacket 11a, and then connect the abnormal approach detection power source 19c, the open/close switch 19e, and the energization state detection circuit 20b. , the energization state detection output circuit 20d, and the jacket 11a, the abnormality detection means is kept in an operable state at all times.

Reference numerals 21, 22, and 23 are return buttons for 1, 2, and 3, respectively, attached to the control means 14, which are pressed and operated after the abnormal situation of each line has been dealt with and returned to normal. This is to delete the stored abnormality registration.

Next, the welding robot 7 moves to the processing station 1.
Workpieces W1, W2, placed at a, 2a, 3a,
The automatic welding of W3 in sequence will be explained with reference to the flowcharts of FIGS. 3 and 4. Note that Po indicates the reference point.

Now, in the initial state, processing station 1a,
Workpieces W1, W2, and W3 are placed in 2a and 3a, respectively.
It is assumed that pallets 4, 5, and 6 loaded with are placed and fixed in position by locking devices 8, 9, and 10, and among these, workpiece W2 has an abnormal protrusion t in the middle of the weld line. .

(1) First, determine whether the program includes welding command information.

(2) If it is included, specify 1→2→3 as the processing order.

(3) Next, switch the selector switch 19d to the welding power source 1.
Command the operation to switch to 9a.

(4) Determine whether the torch 11 is located at the reference point Po.

(5) If it is not located, move torch 11 to the reference point.
Command the positioning operation to Po.

(6) Determine whether line 1 is an abnormal registration. Since this is the initial state, there is no abnormality registration, and the determination is "NO".

(7) Determine whether the pallet 4 is placed at the processing station 1a.

When the pallet contact detection signal from the locking device 8 is received, it is judged as "YES".

(8) Move the torch 11 to the welding start point P _1s of the work W1
Command the positioning operation.

(9) Next, command execution of welding work. Thereby, the torch 11 performs automatic welding along the welding line from the point P _1s to the welding end point P _1e .

(10) During the execution of welding work, it is determined whether an abnormality is detected for each unit movement amount (step amount) of the torch 11. If there is no "energization" signal from the energization state detection circuit 20d, it is determined as "NO".

(11) Next, it is determined whether the torch 11 has reached the welding end point P _1e . If "YES", a command is given to stop the welding work. As a result, the changeover switch 19d is switched to the sensor power source 19b, and the feeding of the electrode 13 is stopped due to the rotation of the feeding roller 17 being stopped.

(12) Next, command is given to return the torch 11 from the welding end point P _1e to the reference point Po.

(13) Command the release of pallet 4. This releases the locking device 8 and releases the pallet 4 from its fixed position.

(14) Next, command the pitch drive of line 1.
As a result, the roller conveyor of line 1 is driven one pitch, and the pallet 4 loaded with the unwelded workpiece W1 is newly placed at the processing station 1a, and the pallet 4 is positioned and fixed by the operation of the locking device 8 in sequence. .

(15) Determine whether to move to the next line and select “YES”
If so, return to steps (2) and (3) above.

Then, steps (3) and subsequent steps are executed for the workpiece W2 on line 2, but during the welding operation in step ( ₉ ), the jacket _11a is When approaching the abnormal protrusion t of the workpiece W2, current flows between the mantle 11a and the abnormal protrusion t, causing discharge, and a change in voltage and/or current is detected by the energization state detection circuit 20b, which outputs the energization state detection output circuit. A "energization" signal is issued to the control means 11 from 20d. Therefore, it is determined "YES" in step 10, the welding work is ordered to be interrupted, and the torch 11 is moved to the abnormality point P _2i.
At the same time, the changeover switch 19d is switched to the sensor power supply 19b, and the feed roller 1
When the rotation of the electrode 7 is stopped, the feeding of the electrode 13 is also stopped.
At the same time, it outputs a command to activate an alarm device (not shown; for example, a buzzer or a flashing lamp) attached to the control means 14. Then, it is registered that line 2 is abnormal.

Next, backtracking of the torch 11 from the abnormality point _P2i to the reference point Po is commanded. As a result, as shown _in FIG _.
→Po) and safely return to the reference point Po.
This backtracking step continues between steps (14) and (15).

Next, return to the steps (2) and (3) above and return to line 3.
Step (3) and subsequent steps are executed for workpiece W3.
If there is no abnormality in this line 3, return to line 1 and perform the same steps for workpiece W1.
Execute (3) to (15).

Then, even when it is line 2's turn again, the above-mentioned abnormality on line 2 is still not taken care of.
If the return button 22 is not operated, the control means 14 judges ``YES'' in step (6) and proceeds between steps (14) and (15), so that the torch 11 jumps over line 2 where the abnormality is being registered. Then, it will move to line 3. Thereafter, unless the front/rear return button 22 is operated, the torch 11 will move to the workpieces W on lines 1 and 3.
1 and W3 are automatically welded alternately.

Eventually, the worker noticed the activation of the alarm, put a special mark on the workpiece W2 with the abnormal protrusion t, manually released the locking device 9 separately from the welding robot 7, and shut down the roller conveyor of line 2. 1
The pallet 5 carrying the workpiece W2 is newly placed on the processing station 2a by pitch driving, and the locking device 9 is operated again to position and fix the pallet 5. If the operator presses the return button 22 after processing line 2 in this way, the above-mentioned abnormality registration will be deleted, so the welding robot 7 will return to the normal order of lines 1 → 2 → 3 from the next time. perform automatic welding.

Also, when the judgment in step (7) is "NO" due to a failure of the roller conveyors or lock devices 8, 9, 10, etc. of lines 1, 2, and 3, the alarm is activated and the abnormality of the line is registered. , jump over that line and move to the next line.

In the above-mentioned embodiment, the abnormality detection means provided in the welding robot 7 was designed to detect an "abnormality" when the torch mantle approaches an abnormal protrusion of the workpiece. The present invention can be similarly implemented using other abnormality detection means, such as means for detecting a previous defect or means for detecting an abnormality in a workpiece using a television camera.

As described in detail above, according to the control method of the present invention, before starting automatic welding on a workpiece placed in a processing station, it is possible to check whether the line has been registered as abnormal, or whether the line has previously had an abnormality and is being dealt with. If the abnormality remains registered, the line is skipped over and moved to the next line, so when workpieces flowing through multiple lines are sequentially machined, an abnormality occurs on one line. However, the transfer of other lines is not stopped, and the decline in production efficiency can be minimized, which is particularly effective when applied to production lines in unmanned factories.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of a processing line including a welding robot as an example of implementing the control method of the present invention, FIG. 2 is a circuit block diagram mainly of the power supply device of the welding robot, and FIG. 3 is an explanatory diagram of the operation. Figure 4 is a flowchart. In the figure, 1, 2, 3 are processing lines, 4, 5, 6 are pallets, 7 is a welding robot, 11 is a welding torch, 12 is a power supply device, 14 is a control means, W1, W
2. W3 is the workpiece, and Po is the reference point.

Claims (1)

[Scope of Claims] 1. An industrial robot is provided that is shared by a plurality of processing lines, and a processing tool equipped on the robot moves sequentially through the processing lines based on commands from a control means, and performs intermittent operation on each processing line. In an apparatus in which the transferred workpieces are sequentially and automatically processed, a reference point is set for the processing tool to return to each time the processing operation in each processing line is completed, and the control means is configured to control the processing equipment related to the processing line and/or the workpiece. If an abnormality occurs, the abnormality of the processing line is registered, and each time the processing tool returns to the reference point, it is determined whether or not there is an abnormality registered in the processing line to be started from now on, and whether there is an abnormality registered. 1. A control method for an industrial robot, characterized in that the robot is instructed to skip over that processing line and move to the next processing line if the 2. The processing tool according to claim 1, wherein when an abnormality occurs during processing work, the processing tool interrupts the processing work and returns to the reference point by retracing the path up to that point. Control method for industrial robots. 3. A control method for an industrial robot according to claim 1, wherein the control means is provided with a return button for each processing line, and the abnormality registration is deleted by an operation signal of the return button. .