JPH1099735A - Automatic coating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a sparking during a coating operation, coating defects due to an abnormal approach of a coater to an object to be coated and impact of a coater on a object to e coated, from being caused by surely detecting a abnormal approach of a coater to an object to be coated. SOLUTION: In the coating process using this equipment, first, the shape of an object to be coated W and the position of a marker M are detected based on image signals from an image pickup device 6 for photographing the object W and a coater 3 that is provided with the marker M discriminable from the background in an photographic image to be produced by the image pickup device 6, and then, based on the shape of the object W, an abnormal approach region A is set. When the position of the detected maker M enters into the abnormal approach region A, an abnormal approach signal is outputted and therefore, abnormal approach of the coater 3 to the object W can surely be detected depending on whether the abnormal approach signal is outputted or not. Accordingly, sparking is prevented from being caused by cutting off a high voltage applied to the coater 3 or the object W, based on the abnormal approach signal and also, coating defects due to the abnormal approach of the coater 3 are prevented from being caused by interrupting the spraying of a coating material based on the abnormal approach signal and further, impact of the coater 3 on the object W is prevented from being caused by stopping movement of the coater 3 based on the abnormal approach signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic coating apparatus for coating a workpiece while moving a coating machine along the surface of the workpiece.

[0002]

2. Description of the Related Art Automatic coating apparatuses for performing electrostatic coating are roughly classified into three types: an indirect charging system, a gun direct charging system, and a work charging system. In the indirect charging method, a high voltage is applied to a needle-shaped grid electrode arranged around the coating machine, and the coating machine and the object to be coated are set to the ground potential to form an electrostatic field between the grid electrode and the object to be coated. In this method, the paint particles sprayed from the coating machine are charged in the electrostatic field and applied to the object to be coated. The gun direct charging method applies a high voltage to the coating machine itself and grounds the object to be coated. As a potential, an electrostatic field is formed between the coating machine and the object to be coated, and charged paint particles are sprayed from the coating machine and applied to the object to be coated. In addition, the work charging method is completely different from the former two methods, in that instead of applying a high voltage to the coating machine side, the coating machine is set to the ground potential and a high voltage is applied to the object to be coated. Is formed, and the charged paint particles are sprayed from a coating machine to be applied to an object to be coated.

In the case of performing electrostatic coating, if a coating machine is too close to an object to be coated, dielectric breakdown may occur and sparks may occur. For this reason, the grid electrode or the coating machine, to detect the dark current flowing between the object to be coated,
When this exceeds a predetermined current value lower than the current value causing dielectric breakdown, the high voltage supplied to the coating machine or grid is cut off to prevent spark discharge. In this case,
In the case of the indirect heating system or the gun direct heating system, a high voltage is supplied to each coating machine, and a dark current is detected by installing a current detector for each coating machine. Therefore, high voltage can be cut off when any one of the coating machines abnormally approaches the object to be coated.

[0004]

However, in the case of the work charging system, a plurality of coating machines approach or move away from the work at the same time as a high voltage is applied to the work. The current value may be higher in the dark current when approaching the workpiece within a range where multiple painting machines do not cause spark discharge than in the dark current when only the machine abnormally approaches the workpiece. In some cases, it is difficult to detect that the coating machine has abnormally approached the workpiece by simply detecting the current value of the dark current. Further, in an automatic coating apparatus that performs non-electrostatic coating, no electrostatic field is formed between the coating machine and the object to be coated, so no spark is generated when the coating machine comes too close to the object to be coated. However, since the dark current does not flow, it is not possible to detect whether or not the vehicle has approached abnormally based on the current value, and paint adheres when the coating machine comes too close to the workpiece while the coating machine is moving. Or paint failure,
Further, there is a possibility that the coating machine may collide with the workpiece while moving.

[0005] Therefore, the present invention, for example, whether to perform electrostatic coating or non-electrostatic coating, reliably detects that the coating machine has abnormally approached the object to be coated, and detects the spark during coating. It is a technical object to prevent the occurrence of coating, defective coating due to abnormal approach of the coating machine, and collision between the coating machine and an object to be coated.

[0006]

SUMMARY OF THE INVENTION To solve this problem, the present invention relates to an automatic coating apparatus for coating a workpiece while moving the coating machine along the surface of the workpiece.
At the same time, a coating machine with a marker that can be distinguished from the background, and an object to be coated with the coating machine, and an imaging device that captures images from positions that do not overlap each other, and an image signal output from the imaging device. An image processing device that determines whether the coating machine has abnormally approached the object to be coated based on the shape of the object to be coated. An abnormally approaching area setting means for setting an area where the attached marker should not approach the article any more as an abnormally approaching area, and a marker position detecting means for detecting the position of the marker imaged by the imaging device. Abnormal approach signal output means for outputting an abnormal approach signal when the position of the detected marker enters the abnormal approach area.

According to the present invention, a coating machine provided with a marker that can be distinguished from the background, and an object to be coated by the coating machine,
At the same time, since the images are taken so as not to overlap each other, the shape of the object to be coated and the position of the marker are detected from the image signal. Then, for example, when performing electrostatic coating, an area where a spark occurs when the coating machine further approaches the object to be coated is set as an abnormal approach area based on the detected object shape and is detected. If the abnormal approach signal is output when the position of the marker enters the abnormal approach area, the presence or absence of the output of the abnormal approach signal can detect the abnormal approach of the coating machine. In this case, since the marker attached to the coating machine is detected, the marker position is detected in an extremely short time as compared with the case where the shape of the coating machine is recognized based on information of all image signals. The smaller the size of the marker, the better.

Then, if the high voltage applied to the coating machine or the object to be coated is cut off based on the abnormal approach signal,
The high voltage is cut off before the sprayer approaches the object to generate the spark, thereby preventing the occurrence of spark. In addition to preventing the occurrence of sparks during painting, by setting the abnormal approach area arbitrarily, it is possible to prevent painting failure due to abnormal approach of the painting machine and collision between the painting machine and the workpiece Is done.

According to another automatic coating apparatus of the present invention, when performing electrostatic coating, the moving speed vector of the coating machine at the current coating machine position is determined based on the marker position detected at a predetermined time interval. Is calculated, the position of the coating machine is predicted after the elapse of a predetermined time, and an abnormal approach signal is output when the predicted position enters the abnormal approach area. Spark generation,
Poor coating due to abnormal approach of the coating machine and collision between the coating machine and the object to be coated are prevented.

[0010]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic explanatory view showing an automatic coating apparatus according to the present invention, and FIG. 2 is a flowchart showing the image processing procedure.

In the automatic coating apparatus 1 of the present embodiment, a high voltage generator 2 is connected to a coating object W such as an automobile body which is insulated and supported, and a coating machine 3 is connected to the ground. In a state where a voltage is applied to set the coating machine 3 to the ground potential and an electrostatic field is formed between the coating machine 3 and the workpiece W, the paint sprayed from the coating machine 3 is electrostatically applied to the workpiece W. A work application type electrostatic coating device is used. The coating machine 3 is attached, for example, to the tip of a robot arm 5 of an articulated multi-axis control machine 4 installed on the left and right sides of a conveyor for transporting the workpiece, and moves the coating machine 3 along the side of the workpiece W. The coating machine 3 is provided with a marker M of a color different from the background near the tip of the coating machine 3 while being moved.

An image pickup device 6 for picking up an image of the coating machine 3 and the object to be coated W on the same screen is attached to the front or rear in the transport direction of the object to be coated W. In this state, the coating machine 3 and the workpiece W are imaged from a position where they do not overlap each other.
The image processing device 7 determines whether or not the coating machine 3 has abnormally approached the workpiece W based on the image signal and outputs an abnormal approach signal when the coating machine 3 has abnormally approached. Is connected to the high-voltage generator 2 having a high-voltage cut-off circuit (not shown) for cutting off a high voltage applied to the object to be coated W based on the abnormal approach signal. Switch 8 that discharges the electrostatic charge accumulated in the ground to the ground
It is connected to the.

The image processing device 7 detects the shape of the workpiece W, and determines an area where a spark is generated when the marker M attached to the coating machine 3 further approaches the workpiece W based on the shape of the workpiece. Abnormal approach area setting means 9 for setting as an abnormal approach area A; marker position detecting means 10 for detecting the position of the marker M imaged by the imaging device 6 and recognizing the position as a coating machine position; And an abnormal approach signal output means 11 for outputting an abnormal approach signal when the vehicle enters the abnormal approach area A. Since the marker position detecting means 10 detects the marker M attached to the coating machine 3, a very short time is required compared with the case where the pattern recognition of the coating machine 5 is performed based on the information of all the image signals. Can be used to detect the marker position.

The above is an example of the configuration of the present invention, and its operation will be described with reference to FIG. When the object to be coated W reaches a predetermined coating start position, before the coating is started, image processing by the image processing device 7 is started.
In step 1 (STP1), the abnormal approach warning area A is set based on the image input from the imaging device 6. At this time,
The object to be coated W moves slowly to the front side or the opposite side of the screen, and its silhouette hardly changes during painting. Therefore, the shape of the object to be coated W is read out by performing pattern recognition, and the coating machine 3 performs the As described above, the limit area where sparking occurs when approaching the workpiece W is set as the abnormal approach area A.

Here, the paint is sprayed from the coating machine 3 maintained at the ground potential, and a high voltage is applied to the workpiece W to which the high voltage supplied from the high voltage generator 2 is applied, thereby performing electrostatic coating. To start. When the coating is started, the image signal captured by the imaging device 6 is input to the image device 7 at predetermined time intervals, and each time the image signal is input in step 2 (STP2), the process proceeds to step 3 (STP3). Then, the position of the marker M attached to the coating machine 3 is detected and recognized as the coating machine position. In this case, since the marker M attached to the coating machine 3 is detected, the marker position can be detected in an extremely short time as compared with the case where the pattern recognition of the coating machine 5 is performed based on the information of all the image signals. can do. Next, the process proceeds to step 4 (STP4) to determine whether or not the marker M is located in the abnormal approach area A set in step 1 (STP1). If not, the flow returns to step 2 (STP2) and waits until the next image signal is input.
When the vehicle enters the inside, the process proceeds to step 5 (STP5) to output an abnormal approach signal. Then, when the abnormal approach signal is output, the high voltage cutoff circuit in the high voltage generator 2 is operated to cut off the high voltage applied to the workpiece W, and at the same time, the ground switch 8 is turned on. The electrostatic charge accumulated on the object to be coated is released to the ground, and the supply of the coating material to the coating machine 3 is also stopped, so that the coating is interrupted.

In this example, a case has been described where the abnormal approach area A is set each time the object W arrives at the painting position. However, when the silhouette of the object W changes during painting, a predetermined The abnormal approach area A may be updated every time. In addition, when a coating device that performs non-electrostatic coating is used as the automatic coating device 1, when the marker M attached to the coating machine 3 approaches the workpiece W any more, a limit area where coating failure occurs, The area of the limit that collides with the object W when the object W is further approached is set as an abnormal approach area A, and when an abnormal approach signal is output, the spraying of the paint is stopped or the coating is stopped. If the machine 3 is stopped or retracted, coating failure and collision of the paint machine are prevented beforehand. Furthermore, the marker M is not limited to a colored one, and any marker such as a light-emitting body or a reflector can be used as long as it can be distinguished from the background. However, in order to detect the position of the marker M in a short time, The smaller the area, the better.

FIG. 3 is a schematic explanatory view showing another automatic coating apparatus according to the present invention, and FIG. 4 is a flowchart showing the image processing procedure. In addition, the same reference numerals are given to portions common to FIG. 1 and detailed description is omitted. The automatic coating apparatus 21 of this example is designed to predict the position of a coating machine after a predetermined time has elapsed, and the coating machine 3 having a marker M of a color different from the background and the workpiece W are displayed on the same screen. And an image processing apparatus 2 for capturing an image from a position that does not overlap the front and back.
2 are connected.

The image processing device 22 detects the shape of the workpiece W, and generates a spark when the position of the marker M attached to the coating machine 3 approaches the workpiece W further based on the detected workpiece shape. Abnormal approach area setting means 23 for setting an area to be raised as an abnormal approach area B; marker position detecting means 24 for detecting the position of the marker M imaged by the imaging device 6 at predetermined time intervals; Position data storage means 25 for sequentially storing the positions, and at least movement of the current coating machine 3 based on the current position data stored in the position data storage means 25 and one or more position data detected before that. A marker position predicting means for calculating a moving speed vector composed of a direction and a moving speed and predicting a marker position after a lapse of a predetermined time; An abnormal approach signal output means 27 which outputs an abnormal approach signal when overlapping with the abnormal approach area B set by the near area setting means 23.

FIG. 4 is a flowchart showing a processing procedure in the image processing device 7. When the workpiece W reaches a predetermined coating start position, the image processing by the image processing device 7 is performed before the coating is started. When started, first, in step 11 (STP11), the abnormal approach area B is set based on the image input from the imaging device 6. Here, when the electrostatic coating is started, the counter is set to i = 1 in step 12 (STP12).
The image signal is input from the imaging device 6 in step 13 (STP13), and the process proceeds to step 14 (STP14), and the position of the marker M attached to the coating machine 3 based on the image signal is set as the coating machine position. Detect and step 15 (STP15)
Then, the data of the coating machine position is sequentially stored.

Then, in step 16 (STP16), it is determined whether or not the position data of the past two times has been stored. If not, the counter i = 2 in step 17 (STP17).
Then, the process returns to step 13 (STP13). If the data is stored, the process proceeds to step 18 (STP18). Step 18 (STP1
In 8), calculates the moving velocity vector V consisting of the moving direction and the moving speed of the coating machine 3 on the basis of the position data storage unit 25 current stored in the marker position D ₂ and the marker position D ₁ which is previously detected, After a lapse of a predetermined time based on the velocity vector V from the current marker position D ₂ (for example,
Predicting the marker position D ₃ after 0.01 seconds) has elapsed.

Next, the process proceeds to step 19 (STP19), where it is determined whether or not the marker position predicted in step 18 (STP18) is located within the abnormal approach area B set in step 11 (STP11). If the coating machine 3 has not entered the abnormal approach area B, the flow returns to step S13 (STP13) and waits until the next image signal is input. The process proceeds to step 20 (STP20), outputs an abnormal approach signal, and returns to step 11 (STP11).

Then, when the abnormal approach signal is output, the high voltage cutoff circuit in the high voltage generator 2 operates to cut off the high voltage applied to the workpiece W, as described above. At the same time, the ground switch 8 is turned on, the static charge accumulated on the object to be coated is released to the ground, and the supply of the coating material to the coating machine 3 is stopped, so that the coating is interrupted. That is, before the coating machine 3 enters the abnormal approach area B, the supply of the high voltage to the coating machine 3 is stopped, thereby preventing the occurrence of spark.

In the present embodiment, a case has been described in which the position of the coating machine 3 is predicted by calculating the velocity vector based on the current position data and the past one-time position data. If the acceleration, the trajectory, and the like are also calculated based on the position data of times or more, the position of the coating machine can be more accurately predicted. Further, it is needless to say that this embodiment can also be applied to an automatic coating apparatus for performing non-electrostatic coating.

[0024]

As described above, according to the present invention, since the marker attached to the coating machine is detected, the shape of the coating machine is recognized based on the information of all image signals. The marker position can be detected in an extremely short time, and when the detected marker position enters a preset abnormal approach area, an abnormal approach signal is output. Not only has the effect of being able to reliably detect in a short time that the machine has approached abnormally, but if the high voltage applied to the coating machine or the object to be coated is shut off based on this abnormal approach signal, the spark When the spraying of the paint is stopped, the coating failure due to the abnormal approach of the painter is prevented, and when the painter is stopped, the collision with the workpiece is prevented.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an example of an automatic coating apparatus according to the present invention.

FIG. 2 is a flowchart showing the image processing procedure.

FIG. 3 is a schematic explanatory view showing an example of another automatic coating apparatus according to the present invention.

FIG. 4 is a flowchart showing the image processing procedure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Automatic coating device W ... Coating object 3 ... Coating machine M ... Marker 6 ... Imaging device 7 ... Image processing device 9 ... Abnormal approach area setting means 10 ... -Marker position detecting means 11 ... abnormal approach signal output means 21 ... automatic coating device 22 ... image processing device 23 ... abnormal approach area setting means 24 ... marker position detecting means 25 ... position Data storage means 26 Marker position prediction means 27 Abnormal approach signal output means

Claims (2)

[Claims] A marker (M) that can be distinguished from a background in an automatic coating apparatus that coats a workpiece (W) while moving a coating machine (3) along a coating surface of the workpiece (W). An image pickup device (6) for simultaneously picking up a coating machine (3) and an object (W) to be coated by the coating machine (3) from a position where they do not overlap each other; An image processing device (7) for determining whether or not the coating machine (3) has abnormally approached the object to be coated (W) based on an image signal output from the image processing device (6); Is a region where the marker (M) attached to the coating machine (3) must detect the shape of the object to be coated (W) based on the shape of the object to be coated and no more approach the object to be coated (W). An abnormal approach area setting means (9) for setting an image as an abnormal approach area (A); A marker position detecting means (10) for detecting the position of the marker (M); and an abnormal approach signal for outputting an abnormal approach signal when the detected position of the marker (M) enters the abnormal approach area (A). An automatic coating device comprising an output means (11). 2. An automatic coating apparatus for coating a workpiece (W) while moving a coating machine (3) along a coating surface of the workpiece (W), wherein the marker (M) can be distinguished from the background. An image pickup device (6) for simultaneously picking up a coating machine (3) and an object (W) to be coated by the coating machine (3) from a position where they do not overlap each other; An image processing device (22) for determining whether or not the coating machine (3) has abnormally approached the object to be coated (W) based on an image signal output from 6), wherein the image processing device (22) Is a region where the marker (M) attached to the coating machine (3) must detect the shape of the object to be coated (W) based on the shape of the object to be coated and no more approach the object to be coated (W). An abnormal approach area setting means (23) for setting an image as an abnormal approach area (B); Marker position detecting means (24) for detecting the position of (M) at predetermined time intervals, position data storing means (25) for sequentially storing the detected position data, and said position data storing means (25) The moving velocity vector of the marker (M) at least at the current marker position is calculated based on the current position data stored in the memory and one or more position data detected before that, and the marker (M) after a predetermined time has elapsed. Marker position prediction means for predicting position (26)
Abnormal approach signal output means (27) for outputting an abnormal approach signal when the predicted marker position enters the abnormal approach area (B) set by the abnormal approach area setting means (23).
An automatic coating device comprising: