JPS5825284B2 - industrial robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrial robot that performs painting work, for example.

When an industrial robot performs curved movements such as painting work, a continuous path control robot is used.

The principle of this operation is to approximate the motion curve with a group of arbitrary minute straight lines, and create position designation data based on the coordinate designation of each straight line to continuously move the robot (working device).

For example, when such an industrial robot is equipped with a spray gun for painting work and is made to perform painting while moving in a curve, each axis of the industrial robot (or three axes when moving three-dimensionally in space) can be moved arbitrarily. For this purpose, a manual control means such as a bundle is provided, and the object to be coated is actually painted using this bundle or the like.

At this time, the coordinate data indicating the position of each operating axis of the industrial robot as well as the operating timing of the spray gun are converted into a warm-up signal, which is stored in a predetermined storage device such as a magnetic tape in synchronization with sampling pulses generated at fixed time intervals. Record several times.

After that, the position designation data and the work designation data indicating the spray gun operation timing recorded in the storage device are reproduced again in synchronization with the sampling pulse, and the industrial robot uses the read designation data as well. and activate the spray gun.

Therefore, the same painting work will be performed by this industrial robot according to the specified data that has been recorded once.

Conventional control of working time in such industrial robots is carried out by the device shown in FIGS. By pressing , power is applied to the solenoid valve 2, the valve opens, and the paint being supplied to the spray gun 3 is sprayed out.

When the push button switch 1 is opened, the valve 2 is closed, and the painting operation is interrupted while the paint is sprayed out.

Reference numeral 4 denotes a pulse generator that generates sampling pulses 5. A storage device 6 connected to this pulse generator 4 records the open/closed state of the push button switch 1 every time the sampling pulse 5 is supplied.

Note that the pushbutton switch 1 may be any device as long as it can turn on and off the power at will, and the storage device 6 also stores data specifying the position of the robot, that is, the painting device. .

FIG. 1 is a diagram illustrating the flow of signals when performing automatic position control after such recording.
The solenoid valve 2 and spray gun 3 are the same as those shown in FIG.

In the storage device 6, the presence or absence of operation of the spray gun 3 is recorded as work designation data along with signals such as position designation data of the industrial robot, and when a sampling pulse 5 is generated from the pulse generator 4, this pulse 5 causes the storage device to The stored contents of 6 are sequentially read out.

If the read contents include a record for ejecting the spray gun, that is, work designation data, the electromagnetic valve 2 is opened to operate the spray gun, and when the work designation data disappears, the spraying of paint stops.

The disadvantage of these conventional control devices is that when reproducing work specification data to execute a painting job, the spray gun starts (or stops) before the robot reaches the spray gun start (or stop) point recorded in the storage device. Otherwise, it will stop.

FIGS. 2a and 2b are explanatory diagrams of recording and reproducing operations to explain this situation.

In the figure, 1 shows the trajectory of the spray gun, that is, the operation of the quick-production work device, in two-dimensional coordinates (for convenience of explanation), and 2 shows the actual operation of the spray gun by pressing push button switch 1 during manual operation of the handle, etc. It shows the timing when

Here, the horizontal axis indicates time change, and the sampling pulse 5 is made to correspond to this.

Now, move the spray gun along the summer trajectory while moving each axis of the work equipment, turn on switch 1 at point a, or timing t1, to start painting, and turn off switch 1 at point C, or timing t3, to start painting. Let us consider the case where the system is stopped and stored in the storage device 6.

If the sampling pulse 5 is generated in correspondence with the locus 1 of the spray gun as shown in the figure, there is no sampling pulse at the time t1 when the spray gun starts ejecting, and the data immediately after that is stored in the storage device 6. It is recorded by the sampling pulse, that is, the pulse generated at timing t2, and since the spray gun has moved to point b at this time, the actual recording start point is t as shown in the figure (ON).
2, that is, the coordinates of point b are recorded as spray gun position designation data.

The same is true for the operation stop time t3, and even though the industrial robot is actually going to paint between points a and C, the storage device 6 stores points b and d. Work designation data to paint the space will be written.

In other words, the spray gun is operated at timings t2 to L4 that are delayed from the actual painting.

Next, the case where work is carried out while automatically controlling the position of the spray gun by reading the work designation data from the storage device 6 will be explained with reference to Figure 2. In the figure, 1 is the locus of the spray gun shown as two-dimensional coordinates. At the same time, the vertical axis corresponds to the sampling pulse 5 as the time axis.

Here, the curve shown by the broken line is a recording locus that connects the coordinates recorded as position designation data in the storage device 6 corresponding to each pulse of the sampling link pulse 5, and the solid line shows the position designation data in the storage device 6. These are playback trajectories that indicate the position of the spray gun when the industrial robot is moved by reading them out, and deviations between these trajectories occur due to the following circumstances.

In other words, in the continuous path type industrial robot mentioned above,
During playback, the spatial coordinate signals necessary for each axis movement of the industrial robot are sequentially read out from the storage device 6 using sampling pulses 5 having a fixed time interval, and these are given as target positions to a control system, such as a servo mechanism, to determine the current position of each axis. Each axis is moved in the direction that eliminates the difference between

Therefore, the spray gun moves in space while tracking the target position, and there is always a delay time TD as shown in the trajectory 1 above.

Because of this delay time TD, as shown in Figure 2 (2) and (2), the spray gun coating position (2) is earlier than the recorded position (3).

In other words, if a signal to turn on the spray gun is read from the storage device at point A, at this time the spray gun has only reached point a, even though it actually corresponds to point α on the playback trajectory. do not have.

Similarly, if a signal to turn off the spray gun at point B is read from the storage device, even though the position corresponding to point β on the playback trajectory is specified as the work stop position, it is actually on the playback trajectory. The painting work will stop at point b.

Automotive spot welding, which is the main application field of conventional industrial robots, uses a point-to-point control method called the PTP method, which requires recording only the minimum number of points necessary for operation. The positioning accuracy of the points is important, the path between the points does not matter, and the faster the speed, the better.

On the other hand, painting work has recently attracted attention as a new field of application for industrial robots.

Path and speed are important in painting work, and we tried to apply it to painting work by using an approximate continuous path type that is an extension of the PTP method that divides a curve into a group of minute straight lines.
As long as the path is divided into minute parts, there will be a delay in recording, and P
Since the TP method is inseparable from the servo mechanism that operates to follow the target value, it has the disadvantage that the on/off operating point of the spray gun becomes earlier during regeneration.

No matter how good the reproducibility of path and speed becomes, this drawback remains and becomes a fatal drawback for painting operations.

This invention was made to eliminate the above drawbacks.
A storage means for simultaneously storing data regarding the position of the working device and data regarding the work in synchronization with the sampling pulse when the working device attached to the tip of the robot arm is manually operated; In an industrial robot comprising a reproducing means of a servo control system that operates a working device based on position-related data read out in synchronization and work-related data, the work-related data read from the storage means is combined with the position-related data. The object of the present invention is to provide a highly reliable industrial robot, which is equipped with means for supplying the data to the reproducing means with a delay of a predetermined period of time, so that the recorded contents of the work position match the work execution position. There is.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows a circuit block for adjusting the delay in the spray gun operating position during a recording operation of an industrial robot, such as a painting device, that is, a continuous path type industrial robot.

11 is a push button switch, 12 is a solenoid valve, 13 is a spray gun, 14 is a sampling pulse generator 15, and 16 is a storage device, which may be considered to be the same as those in the conventional devices 1 to 6.

17 is an R8 type flip-flop circuit provided between the push button switch 11 and the solenoid valve 12, and has the following functions.

That is, in a state where a logic "0" signal is applied to the reset terminal R, the logic state of the input applied to the set terminal S is output to the output terminal Q at the time when a clock pulse is input to CP, and the next The logic state of output terminal Q is held until a clock pulse is input to CP.

That is, with the logic "1" input to the set terminal S,
When a clock pulse enters the CP terminal, Q becomes logic 2111+
When the set terminal S is at logic +1011 and a clock pulse is input to the CP terminal, Q continues to output logic °°0'''.

In addition, when a logic II 1 jj times signal is input to the reset terminal R, it has the function of outputting logic "0" to the output terminal Q, regardless of the logic state of the set terminal s and cp terminal, and the logic "0" is output to the reset terminal R. If a clock pulse momentarily becomes a logic "1", the output terminal Q continues to output a logic "0" until the next clock pulse is applied to the CP terminal.

The reset terminal R of this flip-flop circuit 17 has
A reset pulse generator 18 is connected, and the flip-flop circuit 17 can be reset as necessary, such as when starting or stopping the device or when an abnormal condition occurs.

Further, a pulse generator 14 is connected to the CP terminal of this flip-flop circuit 17, and the above-mentioned sampling pulse 1
The work specification data is stored in storage device 1 at the timing of synchronization with 5.
6.

In addition, 18 is a robot axis position detector,
The dimensional coordinates are detected and written into the storage device 16.

In the industrial robot configured as described above, the operation of writing a certain painting operation into the storage device 16 while arbitrarily moving each axis of the industrial robot will be explained.

When the push button switch 11 is pressed at the position where painting is actually performed, a logic "1" signal is applied to the set terminal S of the flip-flop circuit 17.

At this time, the output terminal Q does not immediately become logic "1", so the solenoid valve 12 does not operate and no paint is sprayed from the spray gun 13.

When the push button switch 11 is pressed continuously, the pulse generation circuit 14
The sampling pulse 15 from CP is input to the CP terminal, the output terminal Q changes to logic "1", the solenoid valve 12 is opened, and paint is ejected from the spray gun 13. At the same time, the sampling pulse 15 operates the memory device 16 and the flip-flop circuit 17 is activated. Record that the output terminal Q is at logic "1".

Furthermore, in synchronization with the sampling pulse 15, the position of the robot at this sampling time (position designation data) is
is written into the storage section 16 at the same time as the work designation data.

If the push-button switch 11 is continued to be pressed, the output terminal Q will maintain the logic "1" state, and the spray gun 13 will continue to spray paint and the sampling pulse 15 will
The state continues to be stored in the storage device 16.

Next, when the push button switch 11 is released, the flip-flop circuit 17
The set terminal S immediately becomes logic "0", but the output terminal Q changes to logic "0" and stops ejecting paint only after the clock pulse is input, so the state of the spray gun 13 is recorded in synchronization with the sampling pulse 15. be done.

Note that if the push button switch 11 is left released, the output terminal Q of the flip-flop circuit 17 will maintain the logic "0" state and no paint will come out. continue to be remembered.

Next, the industrial robot in the regeneration operation will be explained with reference to FIG.

Note that the same reference numbers are used for the same parts as in FIG. 3, and only the blocks necessary for regeneration during automatic position control of the spray gun 13 are shown here.

The storage device 16 stores the stored position designation data in D.
/A+ Sends to servo amplifier 23.

The D/A+servo amplifier 23 converts the input position designation data into an analog signal, amplifies it, and sends it to the actuator 23.

This actuator 23 sets the position of the robot.

Further, the self-storage device 16 sequentially stores N pieces of J data between the terminal for reading out the stored work designation data and the solenoid valve 12.
K type flip-flop circuit 191, 192...19N
A reset signal is supplied from the reset pulse generation circuit 20 to the reset terminal R of each flip-flop circuit 191 to 19N.

21 is an inverter circuit, which is similar to the above flip-flop circuit 1;
9, is provided so that a signal inverted from that of the J terminal is supplied to the terminal.

The sampling pulse 15 is also supplied to the CP terminal of each flip-flop circuit 19 to 19N together with the storage device 16.

By the way, in the JK type flip-flop circuits 191 to 19N, in a state where a logic/tlOt+ times signal is applied to the reset terminal R, logic n1y+ is applied to the J terminal, logic nOtp is applied to the K terminal, and logic "0" is applied to the CP terminal. ″→Logic”
When a clock pulse that changes from 1 to logic 0 is applied, the clock pulse changes from logic fl i 11 to logic u
At the point when the clock pulse completely changes to 011, that is, when the clock pulse has finished inputting completely, logic "1" is generated at the output terminal Q, logic "0" is generated at the output terminal Q, and the next clock pulse is about to be input. and maintain this state.

Conversely, give logic ``1'' to the J terminal and logic ``1'' to the terminal, and CP
When the clock pulse is input to the terminal, a logic "0" is generated at the output terminal Q, a logic n 1 u is generated at the output terminal, and this state is maintained until the next clock pulse is input.

Also, when logic "1" is given to the reset signal R, J,
Regardless of the logic state of each terminal of the CP, a logic "0" is generated at the output terminal Q, and a logic IT 1 ff+ is generated at the output terminal budget.

If the signal applied to the reset terminal R is a single pulse of logic ``1'', logic ``0'' is generated at the output terminal Q, logic ``1?1'' is generated at the output terminal 2, and the next clock signal is generated at the CP terminal. This state is maintained until the pulse input is completed.

In the industrial robot configured as described above, when a desired painting operation is recorded in the storage device 11 as work designation data together with position designation data, the pulse generator 14
The recorded contents are sequentially read out from the storage device 16 by the sampling pulse 15 .

First, each flip-flop circuit 191, 192...19
Assuming that all N are in a reset state, and when one sampling pulse finishes inputting to the memory device 16, the work designation data is generated as a signal to start painting with a spray gun, then the flip-flop The J terminal of the pull circuit 19 has a logic "1", and the K terminal has a logic II O11.

However, at this point, the Q terminal is still logic ++ Q 19
, the Q terminals remain at the logic "'1", and the same applies to the flip-flop circuits 192 to 19N in the subsequent stages.

Then, only after the next sampling pulse has been generated, the Q terminal of the flip-flop circuit 191 becomes logic "'1".
, the Q terminal becomes logic "0".

These Q. Q terminal is the next stage flip-flop circuit 192
J.

Since they are respectively connected to the K terminal, the logic state of the output terminal of the flip-flop circuit 192 changes with the next sampling pulse.

In this way, by the sampling pulse 15, the coating start signal to the spray gun 13 is sequentially transferred to the subsequent stage flip-flop circuits 19□...19N, and the output terminal Q of the final stage flip-flop circuit 19N becomes logic "1". The solenoid valve 12 opens for the first time, and paint is sprayed from the spray gun 13.

Even if the output of the storage device 16 changes to logic "0" (that is, spray gun painting is completed) and work designation data is generated, the solenoid valve 12 is closed only when it is transferred to the final stage flip-flop circuit 19N. The paint squirt ends.

In other words, the ON/OFF signal from the storage device 16 to the spray gun 13 is delayed from the sampling pulse 15 by the number N of flip-flop circuits, and is sent to the spray gun 13 with a delay of the number N of flip-flop circuits.
It can be conveyed to

Thus, the device designation data constituted by the storage device 16 is sent to the D/A+servo amplifier 22.

The D/A+servo amplifier 22 converts the input position designation data into an analog signal, amplifies it, and sends it to the actuator 23.

This actuator 23 sets the position of the robot.

In other words, the position designation data and work designation data stored in the storage device 16 are read out at the same time.

Therefore, in the PTP method described above, the position when the work designation data is reproduced is advanced by a position corresponding to the time TD delayed by several sampling times from the timing at which the work designation data is read from the storage device. By connecting 191 to 19N as many times as the delay time TD, it is possible to paint a location that matches the read work designation data and the corresponding position designation data.

In other words, the recorded contents of the storage device 16 and the painting work executed by reproducing the contents are reliably consistent.

In addition, in the embodiment described above, flip-flop.

The tube circuit 17 or 191 to 19N is not necessarily R8.
It does not have to be the J-type or JK-type, but it can be used as long as it transmits the signal of the push button switch 11 to the solenoid valve 12 in synchronization with the sampling pulse, as it can be used when recording the work designation data shown in Fig. 3. Furthermore, during the reproduction shown in FIG. 4, any device having the function of a shift register that sequentially delays and transfers the work designation data read out from the storage device by the sampling pulse 15 may be used.

Industrial robots configured and operated in this way can be used on a working day.

A major feature of this system is that the recording and spray gun operation are reliably matched by synchronizing the spray gun operation with the sampling pulse that determines the control timing during recording, and furthermore, it eliminates the need to make the sampling pulse interval excessively small. The problem is that the storage capacity is consistent with the capacity needed to reproduce the path.

It should be noted that the delay in spray gun operation cannot normally be recognized by human senses.

Furthermore, during playback, the characteristics of the PTP method are used to cause the spray gun operation to be performed with a time delay of an integral multiple of the sampling pulse interval, and the spray gun operation during playback and the spray gun operation during recording are performed. definitely agrees with.

Incidentally, since the operation delay is usually only one or two sampling pulses, the circuit can be constructed very simply as a result.

The present invention is not limited to the embodiments described above, and can be applied to painting robots that use a spray gun as a working device. It is possible to record the coordinates at each time interval, read out the recorded coordinates at regular time intervals during playback, and use a servo mechanism that works in the direction to eliminate the difference between the coordinates and the current coordinates of the moving part. It can be applied to all mechanical devices that perform work, and a typical example of such a device is an approximate continuous path type industrial robot that is an extension of the PTP method.

As described above, according to the present invention, the working device attached to the tip of the robot arm is manually operated to generate data regarding the position of the working device and data regarding the work in synchronization with sampling pulses. In an industrial robot comprising a storage means for storing data at the same time, and a reproduction means of a servo control system that operates a working device based on position data and work data read out from the storage means in synchronization with a sampling pulse, The present invention is equipped with means for supplying the work-related data read from the means to the reproducing means after delaying the position-related data by a predetermined period of time, so that the recorded work position and the work execution position match. It is possible to provide an industrial robot that takes advantage of the advantages of an industrial robot based on the PTP method, that is, the stable data storage function provided by the sampling panel, and has improved reliability and precision in operation control.

[Brief explanation of the drawing]

Fig. 1 atb is a circuit diagram showing the recording, reproducing and reproducing parts of work designation data in a conventional industrial robot, Figs. 2 a and b are operation explanatory diagrams of the conventional device, and Figs. 3 and 4 are FIG. 1 is a block diagram of a painting apparatus equipped with an industrial robot according to the present invention. 11...Push button switch, 12...Solenoid valve, 13...Spray gun, 14...Pulse generator, 15...Sampling pulse, 1
6...Storage device, 1γ...R8 type flip-flop circuit, 18...Reset pulse generator, 19, ~19N...JK type flip-flop circuit .

Claims (1)

[Claims] 1. A storage means for simultaneously storing data regarding the position of the working device and data regarding the work in synchronization with sampling pulses when the working device attached to the tip of the robot arm is operated by hand, and a sampling pulse from the storage device. In an industrial robot comprising position data read out in synchronization with data and a reproduction means of a servo control system that operates a working device based on the work data, the work data read from the storage means is combined with the position data. and means for supplying the regenerating means to the regenerating means with a delay of a predetermined time.