JPH018312Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a workpiece discrimination device that discriminates the type and position of a workpiece.

In automatic production systems, a workpiece discrimination device that discriminates the shape and position of a workpiece is often used. For example, in an automatic painting system as shown in Fig. 1, a workpiece 1 is suspended on a conveyor 2 and transported to the work area of a painting robot 3, and then the painting robot 3 performs painting work based on a predetermined program. However, in this case, a workpiece discrimination device is used that images the workpiece 1 with an industrial television camera (hereinafter simply referred to as TV camera) and discriminates the type of workpiece, degree of inclination, etc. based on the imaged result.

Then, from among multiple painting programs that are preset according to the degree of inclination and type of workpiece,
A coating program corresponding to the discrimination result of the workpiece discriminating device is selected, so that automatic coating work on the workpiece 1 can be performed satisfactorily.

By the way, the workpiece 1 being conveyed to the conveyor 2 shakes significantly when the running speed of the conveyor 2 suddenly changes (such as immediately after the conveyor 2 is started). If the TV camera takes an image while the workpiece 1 is shaking, errors such as erroneously determining the degree of inclination of the workpiece 1 or erroneously determining the type will occur. Discrimination devices do not have a means to avoid such errors, and therefore have the drawback of causing malfunctions in automatic operations and reducing reliability and efficiency.

In view of the above-mentioned circumstances, this invention provides a workpiece discrimination device that can prevent erroneous judgments caused by workpiece shaking. The shape of the workpiece is determined based on this imaging signal.
In the workpiece discrimination device that determines the position, a shake detection section detects the shaking state of the workpiece and outputs a discrimination prohibition signal when shaking is detected, or detects a sudden change in the conveyance speed of the conveyor, and detects a sudden change in the conveyance speed of the conveyor. It is characterized by comprising at least one of the speed change detection units that outputs the discrimination prohibition signal when the discrimination prohibition signal is detected, and prohibits discrimination of the workpiece based on the imaging signal when the discrimination prohibition signal is output. It is said that

Embodiments of this invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the structure of the first embodiment of this invention. Note that this embodiment is an embodiment in which this invention is applied to the automatic painting system shown in FIG.

In FIG. 2, 5 is a transmitter that is attached to the conveyor 2 (FIG. 1) and emits a pulse train corresponding to the running speed of the conveyor 2. This pulse train is waveform-shaped by a waveform shaper 6, and a third This results in a pulse train _P1 as shown in Figure A. 7 is a timer, and from when the reset signal S ₁ (D in FIG. 3) is supplied to the terminal 7a, the output signal is set to the "H" level for the timer time T ₁ (FIG. 3 B). 9 is an AND This counter performs an up-count operation when the output signal of the gate 8 rises, and is reset when a reset signal _S1 is supplied to the terminal 9a.1.
0 detects the deviation between the count result of the counter 9 and the reference value Ns set internally in advance, and when this deviation is greater than a predetermined set value ΔD, it determines that shaking has occurred and outputs an output signal. Set it to “L” level,
This is a size discriminator that determines that the workpiece is substantially stationary when the deviation is less than the set value ΔD, and outputs the output signal at the "H" level.The "H" level measurement signal _S2 is supplied to the terminal 10a. The output signal is supplied to the on-delay timer 11 only when the on-delay timer 11 is in use. The on-delay timer 11 starts when the signal supplied to the input terminal becomes "H" level.
After the timer time _T2 has elapsed, the output signal is set to "H" level. Note that the speed change detection section 12 is configured with the above-mentioned configuration, and the above-mentioned reference value
Ns, the set value ΔD, the timer time _T2 , and the vibration detection principle in the magnitude discriminator 10 will be described later.

Next, the operation of this embodiment will be explained.

First, when the conveyor 2 runs, the oscillator 5 supplies a pulse train corresponding to the traveling speed to the waveform shaper 6, and as a result, the waveform shaper 6 outputs a pulse train _P1 as shown in FIG. 3A. Next, when the reset signal _S1 is supplied to the timer 7 and counter 9,
Counter 9 is reset and timer 7
An "H" level signal is output from. As a result, the AND gate 8 allows the pulse train _P1 to pass only during the timer time _T1 , so that its output signal becomes as shown in FIG. 3C. Therefore, the count result N of the counter 9 indicates how many pulses are included in the pulse train _P1 during the timer time _T1 , that is, it is a value corresponding to the running speed of the conveyor 2. Then, the size discriminator 10 takes the deviation between the count result N and the reference value Ns, and this deviation is the set value ΔD.
Determine whether it is within the range. In this case, the reference value Ns
is set to a value corresponding to the reference traveling speed of the conveyor 2, and since the conveyor 2 is controlled to always maintain the reference speed while traveling, the deviation is approximately 0 in a steady state. On the other hand, immediately after the conveyor starts or immediately before the conveyor stops, the traveling speed of the conveyor 2 becomes slow, so the above-mentioned deviation becomes large. When the speed deviation is large like this, it is a case where the conveyor speed suddenly changes, that is, a state where shaking occurs.

The above-described set value ΔD is set in accordance with an allowable deviation amount that does not cause shaking. Therefore, if the deviation is greater than or equal to ΔD, the shaking is occurring,
If the deviation is ΔD or less, it can be determined that the state is substantially stationary. Then, the measurement signal S ₂ is detected by the size discriminator 1
0, the magnitude discriminator 10 supplies the signal _S3 , which is the determination result, to the on-day delay timer 11.
FIG. 3 is a waveform diagram of the signal _S3 when it is determined that the device is in a substantially stationary state, and as shown in this figure, it is output in synchronization with the measurement signal _S2 . When the signal _S3 is at the "L" level, the on-delay timer 11 immediately sets the output signal to the "L" level, and when the signal _S3 is at the "H" level, the output signal is set to the "H" level after the timer time _T2 has elapsed. ”
level. The reason for providing the timer time _T2 in this way is that even if the deviation is within the reference value ΔD, the shaking may not have subsided immediately after it falls within the reference value. This is to ensure reliability in detecting a stationary state. Therefore, the timer time _T2 is set corresponding to the time from when the deviation falls within the reference value ΔD until the shaking stops. Then, if the video signal of the TV camera that is capturing the workpiece 1 is taken in only when the output signal of the on-delay timer 11 is at the "H" level, this video signal will always be the video signal when the workpiece is stationary. There is no need to worry about misjudging the degree of inclination or the type of workpiece.

FIGS. 4 and 5 are schematic diagrams showing the mechanical construction of a second embodiment of this invention.

In FIG. 4, 15 is a light shielding plate attached to the hanger 16, and 17 in FIG.
Reference numerals 18 denote a light emitter and a light receiver, which are fixed opposite to the movement path of the light shielding plate 15, respectively. In this case, the light shielding plate 15 is configured so that when the work 1 is conveyed to the conveyor 2 in a substantially stationary state, the light irradiated by the light emitter 17 crosses the light only once. and,
According to the above-described configuration, when the workpiece 1 is being transported while shaking (see the broken line in FIG. 4), the light shielding plate 15 crosses the irradiated light from the light emitter 17 multiple times, so that the output signal from the light receiver 18 The shaking of the workpiece 1 can be detected based on the following. Then, if shaking is detected, similar to the first embodiment,
Prevent video signals from TV cameras from being captured. The electrical configuration of this second embodiment may be, for example, the circuit configuration shown in FIG. In this figure, 20 is a comparator which outputs an "L" level signal when the content of the counter 9 is 2 or more.
An “H” level signal is output in the following cases. Using the output signal of the comparator 20, the video signal capture is controlled in the same manner as in the first embodiment. Furthermore, due to the circuit configuration shown in Fig. 6,
A shaking detection section 25 is configured.

The first and second embodiments described above are both examples in which this invention is applied to an automatic painting system using a painting robot, but this invention can of course be applied to other uses.

As explained above, according to this invention, in a workpiece discrimination device that images a workpiece conveyed by a conveyor with a video camera and discriminates the shape and position of the workpiece based on the imaged signal, the vibration of the workpiece is A vibration detection unit that detects the state and outputs a discrimination prohibition signal when vibration is detected, or a speed that detects a sudden change in the conveyance speed of the conveyor and outputs the discrimination prohibition signal when a sudden change is detected. At least one of the change detection units is provided, and when the discrimination prohibition signal is output, discrimination of the workpiece based on the imaging signal is prohibited, so that errors in shape or position caused by shaking of the workpiece can be prevented. Judgments can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an example of an automatic painting system, Fig. 2 is a block diagram showing the configuration of the first embodiment of this invention, and Fig. 3 A to F show the respective parts of the circuit shown in Fig. 2. A waveform diagram showing waveforms, FIGS. 4 and 5 are schematic configuration diagrams showing the mechanical configuration of the second embodiment of this invention, and FIG. 6 is a block diagram showing the electrical configuration of the same embodiment. . 12... Speed change detection section, 15... Light shielding plate, 1
7... Emitter, 18... Light receiver, 25... Shake detector.

Claims (1)

[Scope of utility model registration request] In a workpiece identification device that images a workpiece conveyed by a conveyor using a video camera and determines the shape and position of the workpiece based on the imaged signal, a shaking state of the workpiece is detected and shaking is detected. The conveyor belt includes at least one of a vibration detection section that outputs a discrimination prohibition signal to the conveyor, and a speed change detection section that detects a sudden change in the conveyance speed of the conveyor and outputs the discrimination prohibition signal when the sudden change is detected. The workpiece discriminating device is characterized in that, when the discrimination prohibition signal is output, discrimination of the workpiece based on the image pickup signal is prohibited.