JPH0562032B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a welding monitoring device for monitoring welding waveforms during welding in resistance welding, percussion welding, and the like.

(Prior art) Conventionally, devices related to this type of device include:
For example, one disclosed in Japanese Unexamined Patent Publication No. 61-49793 is known.

This device reads the welding voltage waveform in advance, determines the tolerance range determined by each reference waveform of the upper limit value and the lower limit value based on it, and checks whether the detected welding voltage waveform during welding is within the tolerance range. Therefore, it is possible to judge the quality of welding.

Further, welding voltage waveforms and current waveforms generally consist of complicated curves.

(Problems to be Solved by the Invention) In this way, in the conventional device, welding is performed based on whether the waveform of the detected welding voltage during welding is within the allowable range determined by each reference waveform of the upper limit value and lower limit value. All I could know was whether it was good or bad.

Therefore, even if the waveform of the detected welding voltage is within the allowable range and the welding is good, the detected waveform cannot be known in relation to the above-mentioned upper and lower reference waveforms.
Moreover, since the trends of each detected waveform cannot be accurately known, the welding conditions cannot be changed to an appropriate state, resulting in the disadvantage that welding cannot be optimized.

Furthermore, when the waveform of the detected welding voltage is outside the allowable range and a welding defect occurs, it is necessary to determine whether the entire detected waveform is completely outside the allowable range, or whether part of the detected waveform is within the allowable range. Since the condition cannot be known in relation to the reference waveform, when a welding defect occurs, the content and cause of the defect cannot be easily known, and the defect cannot be dealt with accurately and quickly.

Therefore, the present invention enables the welding waveform during welding to be directly known on the screen in relation to each reference waveform that determines the upper and lower limits of the allowable range, thereby improving the welding process. The purpose is to accurately and quickly deal with welding defects.

(Means for Solving the Problems) In order to achieve the above object, the present invention has the following configuration.

That is, the present invention includes: a welding waveform detection means A for detecting a welding waveform; a sample value calculation means B for sampling the detected welding waveform at a predetermined period to obtain each sample value; and regarding a plurality of normal welding waveforms. Upper and lower limit value setting means C that obtains a sample value in advance by the sample value calculation means B and sets an upper limit value and a lower limit value based on the obtained sample value; and a storage means that stores the obtained upper limit value and lower limit value. D, the sample value calculated by the sample value calculation means B from the detected waveform of the welding waveform detection means A during welding, and the upper and lower limit values read from the storage means D so that they do not overlap on the time axis. and an output signal arrangement means E that periodically arranges the output signals in a predetermined order.

(Function) In the present invention, prior to observing the welding waveform, sample values are obtained in advance by the sample value calculation means B for a plurality of normal welding waveforms, and based on the obtained sample values, the upper and lower limit value setting means C performs the observation. Set the upper and lower limits corresponding to the upper and lower limits of the waveform's allowable range. These upper limit values and lower limit values are stored in the storage means D in advance.

Then, when observing the welding waveform, the output signal array means E calculates the sample value calculated by the sample value calculation means B from the detected waveform of the welding waveform detection means A, and the upper and lower limit values read from the storage means D over time. They are arranged periodically in a predetermined order so that they do not overlap along the axis.

Therefore, by supplying the output signal from the output signal array means E to an oscilloscope or the like, the observed waveform can be observed on the same screen at the same time as each reference waveform that defines the upper and lower limits of its permissible range.

(Example) FIG. 2 is a block diagram of an embodiment of the present invention.

In the figure, 1 is in the form of a microprocessor.
It is a CPU (central processing unit), and controls each component according to a predetermined procedure as shown in FIGS. 3 and 4, for example.

2 is memory, which includes a read-only memory (ROM) that stores control procedures for the CPU 1 to control each component, and a random access memory (ROM) that stores data related to welding waveforms as described later. RAM).

A welding waveform detector 3 detects a welding current or welding voltage generated by a welding device during electric welding, and the current or voltage detected by this detector 3 is supplied to a sample holder 4. The sample holder 4 performs sampling at a predetermined sampling period according to a command from the CPU 1, and sends the sampled value to the A/D.
Converter 5 is supplied.

Reference numeral 6 denotes a D/A converter, which converts the digital data according to the present invention, which has been processed as will be described later, from D/A in order to be observed with an oscilloscope 7. Also,
The oscilloscope 7 is supplied with blanking pulses from a blanking pulse generation circuit as described later.

Reference numeral 10 denotes a defective product removal actuator for removing a defective product when the electric welding is determined to be defective as described later. This actuator 10 is driven by a drive circuit 9.

Next, an example of the operation of the embodiment configured as described above will be explained with reference to FIGS. 3 and 4.

In this example, the third
Sample data is recorded, processed, and stored according to the procedure shown in the figure.

That is, the welding waveform detector 3 detects a normal welding waveform, the sample holder 4 samples the detected waveform at a cycle of, for example, 0.1 μsec, and the sample value is A/D converted by the A/D converter 5. and convert it into a digital signal. Each of these processes is performed on, for example, 24 welding waveforms (step S1).

Next, the maximum value and minimum value are selected from among the 24 sample values at each sample point obtained from the 24 sample waveforms, and, for example, ±α is added to each of these values (step S2 ). As a result, as shown in FIG. 5, for example, an upper limit value a and a lower limit value b corresponding to the upper and lower limits of the allowable range of the observed waveform are determined.

Then, each digital data corresponding to the upper limit value a is stored in the memory 2, and each digital data corresponding to the lower limit value b is stored in the memory 2 (steps S3 and S4).

Next, when welding is started and the welding waveform is observed, processing as shown in FIG. 4 is performed.

First, the welding waveform detector 3 detects the observed waveform,
The sample holder 4 receives the detected waveform, for example.
Sample at a cycle of 0.1 μsec and convert the sample value to A/D
The converter 5 performs A/D conversion and stores it in the memory 2 (step S11).

Next, it is determined whether each sample value at each sample point of the observed waveform obtained in this way is within the tolerance range formed between the upper limit value a and the lower limit value b, as shown in Figure 5. judge. If the defective product is not within the allowable range, predetermined processing is performed, such as activating the defective product exclusion actuator 10 to eliminate the defective product (step S12).

Next, the digital data corresponding to the upper limit value a, the digital data corresponding to the lower limit value b, and the digital data corresponding to each sample value of the observed waveform c are sequentially and periodically read out (steps S13 to S15).
These data are converted into analog signals by D/A converter 6. The waveforms D/A converted in this manner become waveforms that are periodically arranged in a predetermined order so as not to overlap on the time axis, as shown in FIG. 6A.

When each of these data is read out a predetermined number of times (steps S13 to S18), the display screen of the oscilloscope 7 displays the upper limit value a, the lower limit value b, and the observed waveform c, as shown in FIG. All three are displayed at the same time.

As shown in FIG. 6B, a blanking pulse is generated from the blanking pulse generator 8 at each output of data related to the observed waveform c, and this pulse is applied to the Z axis of the oscilloscope 7 to generate the observed waveform. Since it provides contrast, it is easy to distinguish it from other waveforms.

In the embodiment described above, as shown in FIG. 4, data is processed by software when observing a welding waveform, and the observed waveform etc. are displayed at the same time. However, it is also possible to configure the control procedure shown in FIG. 4 using hardware as shown in FIG. 7 or FIG. 8, and these embodiments will be described below.

The embodiment shown in FIG. 7 includes an upper limit value memory 11 that stores digital data corresponding to an upper limit value a, a lower limit value memory 12 that stores digital data that corresponds to a lower limit value b, and amplifies and A amplifies the observed waveform during observation. /
The digital data from the memories 11, 12 and the A/D converter 13 is selectively outputted by an electronic switch 14 and supplied to the D/A converter 15. Configure.
Further, the output of the scanning generator 16 is supplied to the memories 11 and 12, the A/D converter 13, and the electronic switch 14, respectively.

In the embodiment having such a configuration, prior to observing the welding waveform, data obtained by the procedure shown in FIG. 3 is stored in the memories 11 and 12, respectively. When observing the welding waveform, the digital data stored in the memories 11 and 12 and the digital data obtained by A/D converting the observed waveform by the A/D converter 13 are sequentially transmitted at a predetermined period by the electronic switch 14. When these data are selected and subjected to D/A conversion by the D/A converter 15, the output has a waveform as shown in FIG. Therefore, in the embodiment shown in FIG. 7, it is possible to display three waveforms simultaneously, similar to that shown in FIG.

Next, another embodiment shown in FIG. 8 will be explained. In this embodiment, the observed waveform is converted to A/D at the time of observation.
The converter 13 performs A/D conversion and stores it in the observed waveform memory 19, and the digital data in the memories 11, 12, and 19 is converted to D/A converters 17, 18, and 20.
Each signal is converted into an analog signal through D/A conversion, and each of these analog signals is sequentially selected at a predetermined period by an electronic switch 14.

Therefore, according to this embodiment, the electronic switch 1
The output waveform from D/A converter 4 becomes as shown in FIG. 9, which is similar to the output waveform of D/A converter 15 in FIG.

(Effects of the Invention) As described above, in the present invention, when observing a welding waveform, the sample value data for the observed waveform and the upper and lower limit data that determine the allowable range of the observed waveform are arranged so that they do not overlap on the time axis. are arranged periodically in a predetermined order to form an output signal, so that by feeding this output signal to an oscilloscope, the observed waveform can be viewed on the same screen at the same time as each reference waveform that defines the upper and lower limits. It can be observed.

Therefore, in the present invention, even when the welding detection waveform is within the allowable range and the welding is good, the detected waveform can be monitored in relation to the upper and lower reference waveforms, and moreover, it is possible to monitor the detected waveform from the trend of each detected waveform. Since the welding state can be accurately known, the welding conditions can be changed to an appropriate state, which has the effect of making it possible to optimize the welding.

Furthermore, in the present invention, when the welding detection waveform is outside the allowable range and there is a welding defect, the defective waveform can be observed in relation to the upper and lower reference waveforms, so when the welding defect occurs, the content and cause of the defect can be easily understood. ,
As a result, the defect can be dealt with accurately and quickly, resulting in improved work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a functional diagram of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, FIGS. 3 and 4 are flowcharts showing an example of the control means, and FIG.
The figures are diagrams showing examples of displaying observed waveforms, etc. according to the present invention, FIG. 6 is a waveform diagram of each part in FIG. 2, and FIG.
8 and 8 are block diagrams showing other embodiments of the present invention, respectively, and FIG. 9 is a waveform diagram showing the output waveform of FIG. 7. A is welding waveform detection means, B is sample value calculation means,
C is upper and lower limit value setting means, D is storage means, and E is output signal arrangement means.

Claims (1)

[Scope of Claims] 1 Welding wave detection means for detecting a welding waveform; sample value calculation means for sampling the detected welding waveform at a predetermined period to obtain each sample value; and determining in advance about a plurality of normal welding waveforms. upper and lower limit value setting means for determining a sample value by the sample value calculation means and setting an upper limit value and a lower limit value based on the determined sample value; a storage means for storing the determined upper limit value and lower limit value; The sample value calculated by the sample value calculation means from the detected waveform of the welding waveform detection means at the time and the upper limit value and lower limit value read from the storage means are periodically determined in a predetermined order so as not to overlap on the time axis. A welding monitoring device comprising output signal array means for arranging output signals.