JP2835708B2 - Control method and device for automatic manufacturing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an unattended controlled manufacturing apparatus. INDUSTRIAL APPLICABILITY The present invention is used for an automatic manufacturing apparatus that repeatedly controls a processing machine with the same control pattern for each product by computer. INDUSTRIAL APPLICABILITY The present invention is used for an automatic manufacturing apparatus that automatically detects that a workpiece has been inserted and executes a machining operation that is automatically programmed. The present invention
Although it was developed and implemented for a box making device for folding cardboard, it can be widely applied to automatic manufacturing devices other than the box making device.

[0002]

2. Description of the Related Art There is a wide variety of control devices provided with a sensor for automatically detecting that a workpiece is set at a fixed position, and executing a pre-programmed machining operation using a detection signal generated by the sensor as a trigger signal. Are known. To explain using a box making device as an example, a corrugated paper board cut into a predetermined shape in a previous process is supplied from a conveyor, and when set at a predetermined position, a sensor detects this and sends out a sensor output. When this sensor output arrives, the control device of the automatic manufacturing apparatus sends a pattern signal for executing the processing operation at a timing programmed to link each operation to the arm drive motor, the pusher drive motor, the pneumatic valve, and the like. Send out. In response, each drive motor rotates in a forward or reverse direction, respectively, at a commanded speed in accordance with the pattern signal, and the pneumatic valve conducts and closes the air pressure for a commanded period of time. Open / close operation is performed.

[0003] In such a device, for example, the monitoring sensors (S ₁ , S ₁ ,
S ₂ ) is provided, and the operation response signals generated by the two monitoring sensors (S ₁ , S ₂ ) are taken into the control device, and it is confirmed that the device responds correctly according to the generated control signal. It is supposed to.

[0004] A large number of such devices are provided along a production line to produce a continuous product. For example, the above-described box-making apparatus manufactures a cardboard box by receiving a supply of cardboard paper, and a cardboard box manufactured by this box-making apparatus with 12 products (eg, a disposable diaper) flowing from another manufacturing line. It is designed to be boxed inside.

[0005]

In a production line arranged in this manner, if one device produces a defective product, the overall flow is affected. Therefore, the occurrence rate of the defective product is reduced in the overall operation. This is a big problem. The present inventor has long been involved in the control of this automatic manufacturing apparatus and has been striving to continuously operate each automatic manufacturing apparatus in a good state. When a defective product occurs, the cause is often obvious, and removing the cause solves the problem.

The inventor of the present application has faced the problem that the box-making apparatus intermittently produces defective products whose specific cause is not clear. In the case where defective products are always manufactured under certain conditions, it is relatively easy to solve the problem.However, the problem with the box making equipment here is that in some cases it works continuously and very well. Equipment suddenly produces defective products,
The reason for this is that the operation returns to a good state with the cause unknown. The occurrence of such defective products is extremely rare, and it is often difficult to find the cause. The inventor of the present application performed various observations on the control device, measured and analyzed various electric signals, and found the following.

That is, a general automatic manufacturing apparatus transmits and receives signals in the following procedure. When the workpiece is set at the fixed position, the sensor sends out a detection output. When the trigger signal receiving circuit receives this detection output,
The control circuit sequentially sends out a pre-programmed control signal based on the trigger signal. According to the control signal, the operation of the arm driving motor, the pusher driving motor, the pneumatic valve, and other components is driven so as to be linked. And in order to monitor its operation,
For example, monitoring sensors (S
₁ , S ₂ ) are provided, and the operation response signals generated by the two monitoring sensors (S ₁ , S ₂ ) are taken into the control device, and the device responds correctly according to the generated control signal. To check. The control circuit recognizes that one control operation has been normally performed and completed in accordance with the operation response signal generated by the monitoring sensor.

The inventor of the present application has recorded in detail a time t from a trigger signal generated when a workpiece is set at a fixed position to an operation response signal generated by the monitoring sensor. Then, it has been found that the time t is not always constant in the repetitive operation but varies. When a number of repetitive operations are performed and the time t is plotted in a histogram, it is found that the time t does not vary over the whole but tends to concentrate on some positions (for example, two positions). It was found that there was a great correlation between the statistical data in the histogram and the occurrence of defective products. It was found that the occurrence of defective products was large at a certain concentrated timing when the histogram was high.

The inventor of the present application sought to find out what occurred in the apparatus at the timing when the occurrence of defective products became large, but it was not clear. Probably, it was speculated that the occurrence of rejects was not caused by a problem inherent to the device, but was caused by a major cause other than the device. For example, the fluctuation of the power supply voltage supplied to the device, for example, the fluctuation of the air pressure supplied to the device. This is presumed from such a phenomenon that defective products are frequently generated when the operation of the entire factory is large.

[0010]

The inventor of the present application has decided to deal with the occurrence of a defective product whose specific cause cannot be clarified from the statistical results. That is, a histogram is created for the time t, the time t is compared with the cause of the defective product, and the control circuit is set so that the defective product is generated at a small time t. Specifically, the time t is the time t _{0 at which the} occurrence of defective products is small.
To give a delay. As a result, the occurrence of defective products has been significantly reduced. Some devices have about 2
It was reduced by a factor of one, and on some devices by a factor of eight.

That is, a first aspect of the present invention is a control program which is pre-programmed to control a processing machine based on a trigger signal generated by a sensor for detecting that a workpiece has been loaded and set at a fixed position. In the method for controlling an automatic manufacturing apparatus which generates a signal and receives an operation response signal from the processing machine based on the control signal, a time t from the generation of the trigger signal to the arrival of the operation response signal is increased by a number of times. The processing operation is measured, and the time t is compared with the presence or absence of a defect in each processing operation to determine an optimum value t ₀ of the time t with a small defect occurrence rate.

When a workpiece is put into the apparatus and set at a fixed position, a sensor detects this and generates a trigger signal.
Based on the trigger signal, a pre-programmed control signal for controlling the processing machine is generated, and an operation response signal from the processing machine based on the control signal is received. The time t from the generation of the trigger signal to the arrival of the operation response signal is measured for many machining operations. The frequency of measurement is desirably 100 or more to ensure the actual state of the distribution. For each of the measured times t, the presence or absence of a defect in the machining operation is compared. For example, when the measured time t is made into a histogram, the distribution is distributed in two time zones, and the failure occurrence rate of one of the distributions is large and the failure occurrence rate of the other distribution is small. Then, it is considered that the machining operation at time t belonging to one of the distributions includes some cause of failure. Therefore, an average value, a standard deviation, and a variation coefficient of the other distribution are obtained, and based on the average value, the optimum value t ₀ of the time t with a small defect occurrence rate is set.

A second aspect of the present invention is to generate a trigger signal for detecting that a workpiece is loaded and set at a fixed position in order to perform a processing operation near the obtained optimum value t _0. A sensor, a trigger signal receiving circuit for receiving the trigger signal, a control signal generating circuit for generating a pre-programmed control signal for controlling the processing machine based on the trigger signal, and an operation from the processing machine by the control signal A response signal receiving circuit for receiving a response signal, the control signal generating circuit comprising: a trigger signal receiving circuit receiving a trigger signal, and the response signal receiving circuit receiving an operation response signal. characterized by comprising means for controlling the generation timing of the control signal to be within a time period range t is set to the reception (t ₀ ± Δt) the

A sensor detects that the workpiece is put into the apparatus and is set at a fixed position, and generates a trigger signal. A trigger signal receiving circuit receives the trigger signal and outputs it to the control means. On the other hand, the response signal receiving circuit receives the operation response signal from the processing machine and sends it to the control means. The control means receives the trigger signal and the operation response signal and recognizes that one processing step has been completed. Here, according to the control signal, the control signal generating circuit sets a time t from when the trigger signal receiving circuit receives the trigger signal until the response signal receiving circuit receives the operation response signal to an optimal value t ₀ which is set in advance. The generation timing of the control signal is controlled so as to fall within a time range (t ₀ ± Δt) with reference to.

It is preferable that the trigger signal receiving circuit inhibits a receiving operation from immediately after receiving the trigger signal until at least a time at which the operation response signal is to be received. That is, the circuit of the trigger signal is masked from immediately after the generation of the trigger signal until at least the time when the operation response signal is to be received. As a result, it is possible to prevent a waveform generated by noise from being mixed, and to obtain an accurate measurement value.

Furthermore, a third aspect of the present invention is that the automatic manufacturing apparatus controls a processing machine based on a trigger signal generated by a sensor for detecting that a workpiece is loaded and set at a fixed position. In a control method of generating a programmed control signal and receiving an operation response signal from the processing machine based on the control signal, a time t from the generation of the trigger signal to the arrival of the operation response signal
Is controlled within a set time range (t ₀ ± Δt).

As a result, variations in finished dimensions of processed products can be reduced, and the production yield can be improved. Further, since the supply of the processed product to the main line is performed smoothly, a large loss caused by the line stop can be eliminated.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

[0019]

Next, an embodiment of the present invention will be described with reference to the drawings. The control target device in the present invention is an automatic manufacturing device that repeatedly controls a processing machine with the same control pattern for each product by a computer. FIG. 1 is a block diagram showing a configuration of a main part of the control device according to the embodiment of the present invention.

The control apparatus according to the embodiment of the present invention comprises a control circuit 3 for controlling the cooperative operation of driving means 2 such as an arm drive motor, a pusher drive motor, a pneumatic valve, and a pneumatic cylinder provided in the box-making apparatus 1; Each driving means 2 of the device 1
And an input / output device 4 for taking in an output from the controller and analyzing the data and sending a control signal to the control circuit 3.

The box-making apparatus 1 detects that a workpiece (a sheet of corrugated cardboard in the case of this embodiment) 5 is inserted and set at a fixed position, and uses the detection output as a trigger signal as an input / output device 4. The driving means 2 is provided with a limit switch 7 for generating an operation response signal and transmitting the signal to the data analyzer.

The input / output device (I / O) 4 has a trigger signal receiving circuit 1 for receiving a trigger signal from the sensor 6.
1, a control signal generating circuit 12 for generating a control signal programmed in advance to control the box making apparatus 1 based on the trigger signal and sending the control signal to the control circuit 3, and an operation from the box making apparatus 1 by the control signal A response signal receiving circuit 13 for receiving a response signal, and control means 14 for controlling the control signal generating circuit 12 based on outputs from the response signal receiving circuit 13 and the trigger signal receiving circuit 11 are provided.

Further, as a feature of the present invention, a time t from when the trigger signal receiving circuit 11 receives the trigger signal to when the response signal receiving circuit 13 receives the operation response signal is set in the control signal generating circuit 12. Within the specified time range (t ₀ ±
Means for controlling the generation timing of the control signal is provided so that Δt: t ₀ is an optimum value of the time t at which the defect occurrence rate is small.

FIG. 2 is a side view for explaining a main part of a box making apparatus to be controlled in the embodiment of the present invention, and FIGS.
(D) is a figure which shows the flow of the box making process seen from the arrow A direction shown in FIG. Box making operations of this kind, as shown in FIG. 1, taken on the position of P ₁ on the workpiece (sheet) 5 is the mounting table 21, the mounting table 21 is stopped and moved to the position of P _2. During this movement, a gluing operation (hot melt) is performed, and the respective drive means 2 such as an arm drive motor, a pusher drive motor, a pneumatic valve, and a pneumatic cylinder are driven according to the programmed timing and processing operation in FIG.
The folding work is performed as shown in (a) to (d).

Each processing operation by the driving means 2 in such a box making process is performed at a predetermined timing. However, the operation is performed after a trigger signal indicating that the workpiece 5 is set at a fixed position is generated. time t until the response signal is the incoming, the cause of the many et al, t ₁ shown in FIG. 4,
Variations such as t ₂ , t ₃ , t ₄ ,... may occur. When such driving time exceeds a fixed range is shown, that if many times try to histogram takes the frequency distribution for, the form of distribution and two layers H _A, as shown in FIGS. 5 (a) Often divided into H _B
Investigations revealed that processed products belonging to any of these distributions have a high defect rate. As a specific example, as shown in the completed state plan view of FIG. 6A, the gap at the end portion of the workpiece 5 after completion is within D ₀ (2 mm), whereas the gap of FIG. As shown in FIG. 5, the gap D (about 10 mm) is shown in FIG.
It was contained at a high rate in the distribution _HA of (a). This is shown in FIG.
Failure rate by controlling the generation timing of the distribution H _B side belongs as the control signal as shown in (b) was found to decrease significantly.

The present invention is based on such a fact.
After the sensor 6 detects that the workpiece 5 is put on the mounting table 21 and is set at the fixed position, and generates a trigger signal,
The time t until an operation response signal from the limit switch 7 of the driving means 2 arrives is measured for a large number of (100 or more) machining operations. The measured time t is compared with the presence / absence of occurrence of a defect at each time, and an optimum value t ₀ of the time t at which the defect occurrence rate is small is obtained.

The operation timing of the driving means 2 is controlled based on the optimum value t ₀ obtained in this manner. This optimum value t ₀ is set in advance for an action action selected in a preliminary survey by an operation input. FIG. 7 is a flowchart showing the flow of the control operation based on the optimum value t ₀ in the embodiment of the present invention.

First, the trigger signal receiving circuit 11 of the input / output device 4 inputs a trigger signal from the sensor 6 indicating that the workpiece 5 is put into the box making device 1 and set at a fixed position.
In response to the input of the trigger signal, time measurement of the time t is started, and control signals from the first action to the n-th action are sequentially transmitted to each driving means 2. As an example, n = 12 in this box making device. Each driving means 2 executes the first to n-th operation actions according to the control signal.

Of the first to n-th operation actions, an operation response signal is output from the limit switch 7 of the driving means 2, which is executed relatively later, each time the operation action ends. The response signal receiving circuit 13 receives the operation response signal, stops measuring the time t, and determines whether or not the measured time t is within the allowable range ± Δt with respect to the optimum value t ₀ . If it is within the allowable range, the control operation ends. For example, if the i-th action is shorter than t ₀ -Δt, the control signal generation timing for executing the i-th action is delayed by the time Δt. If the time is longer than t ₀ + Δt, the control signal generation timing for executing the i-th action is advanced by the time Δt.

Here, if the time t becomes equal to or less than t ₀ -Δt, the time from the first action to the n-th action must be delayed by approximately Δt. There is a method. It is simplest to delay the first action by Δt and to delay with it after the second action. This gave good results. However, in general, the i-th action can be delayed (i is 1 to n).
One number up to). It is also possible to distribute Δt to delay some actions little by little, and to delay Δt as a whole.

When the time t is longer than t ₀ + Δt, the same applies to the case where the time for causing the action is advanced.

In the above example, the limit
Although the switch 7 is provided in the driving means 2, it can be provided in a plurality of driving means. Since the operation timings of the respective driving units are different from each other, the above-mentioned optimum times t ₀ are also different from each other. By thus providing a plurality of monitoring sensors and performing overlapping control, the control is further advanced.

In the above control operation, the trigger signal receiving circuit 11 prohibits the receiving operation from immediately after receiving the trigger signal until at least the time when the operation response signal is to be received. Thereby, the circuit of the trigger signal is masked from immediately after the generation of the trigger signal until at least the time at which the operation response signal is to be received, and the operation response signal is transmitted accurately without being affected by noise, thereby reducing the frequency of occurrence of defects. be able to.

[0034]

As described above, according to the present invention, the production yield of products manufactured by an automatic manufacturing apparatus can be improved. In particular, it is possible to diagnose whether or not the machine operation in the manufacturing process, for which the cause cannot be specifically determined, is correct, and correct the trajectory in the direction in which the failure rate decreases. Further, by performing the control according to the present invention, it is possible to smoothly supply the processed product to the main line and to eliminate a large loss caused by the line stop. Furthermore, since the frequency of occurrence of a positional shift or an angular shift of the workpiece to be loaded can be statistically grasped and fed back as control information, the occurrence of an abnormal state can be avoided at an early stage.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a control device according to an embodiment of the present invention.

FIG. 2 is a side view for explaining a main part of a box making apparatus to be controlled in the embodiment of the present invention.

FIGS. 3 (a) to 3 (d) are views showing a flow of a box making process in the embodiment of the present invention viewed from the direction of arrow A shown in FIG. 2;

FIG. 4 is a view for explaining the operation time of a driving means provided in the box making apparatus according to the embodiment of the present invention.

5A is a histogram showing a state before setting an optimum value of the driving operation time according to the embodiment of the present invention, and FIG. 5B is a human sgram after setting the optimum value.

6A is a plan view of a non-defective product in a completed state of a workpiece according to an embodiment of the present invention, and FIG. 6B is a plan view of a defective product in a completed state.

FIG. 7 is a flowchart showing a flow of a control operation in the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 box-making device 2 driving means 3 control circuit 4 input / output device 5 workpiece (sheet) 6 sensor 7 limit switch 11 trigger signal receiving circuit 12 control signal generating circuit 13 response signal receiving circuit 14 control means 21 mounting table

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-103203 (JP, A) JP-A-7-144270 (JP, A) JP-A-63-108406 (JP, A) JP-A 60-103 195609 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G05B 19/05 G05B 13/02 G05B 23/02 B31B 3/00

Claims (5)

(57) [Claims] 1. A control signal, which is pre-programmed to control a processing machine based on a trigger signal generated by a sensor for detecting that a workpiece is loaded and set at a fixed position, is generated, and the control signal is used for the control signal. In the method for controlling an automatic manufacturing apparatus that receives an operation response signal from the processing machine, a time t from the generation of the trigger signal to the arrival of the operation response signal is measured for a large number of processing operations, and the time t is measured. A method for controlling an automatic manufacturing apparatus, comprising: comparing the occurrence of a defect in each machining operation with the presence or absence of a defect to determine an optimum value t ₀ of a time t with a small defect occurrence rate. 2. A sensor for generating a trigger signal for detecting that a workpiece has been loaded and set at a fixed position, a trigger signal receiving circuit for receiving the trigger signal, and controlling the processing machine based on the trigger signal. A control signal generating circuit that generates a pre-programmed control signal, and a response signal receiving circuit that receives an operation response signal from the processing machine based on the control signal. The generation circuit is configured such that a time t from when the trigger signal receiving circuit receives the trigger signal to when the response signal receiving circuit receives the operation response signal is within a set time range (t ₀ ± Δt). A control device for an automatic manufacturing device, comprising: means for controlling a timing of generating a control signal. 3. The control device for an automatic manufacturing apparatus according to claim 2, wherein the trigger signal receiving circuit inhibits a receiving operation from immediately after receiving the trigger signal until at least a time at which the operation response signal is scheduled to be received. 4. A pre-programmed control signal for controlling a processing machine is generated based on a trigger signal generated by a sensor for detecting that a workpiece is loaded and set at a fixed position, and the processing is performed by the control signal. In the method for controlling an automatic manufacturing apparatus that receives an operation response signal from a machine, a time t from the generation of the trigger signal to the arrival of the operation response signal is within a set time range (t ₀ ± Δt). Controlling the generation timing of the control signal as described above. 5. The control method for an automatic manufacturing apparatus according to claim 1, wherein a circuit of the trigger signal is masked immediately after the trigger signal is generated until at least a time when the operation response signal is scheduled to be received.