JP3739144B2 - Automatic painting equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic coating apparatus that coats an object to be coated while moving a coating machine along the coating surface of the object to be coated.
[0002]
[Prior art]
Automatic coating equipment that performs electrostatic coating can be broadly divided into three types: an indirect charging method, a gun direct charging method, and a workpiece charging method.
In the indirect charging method, a high voltage is applied to the needle-shaped grid electrodes arranged around the coating machine, and the coating machine and the object to be coated are grounded 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 by 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.
In addition, the workpiece charging method is completely different from the previous two methods. Instead of applying a high voltage to the coating machine side, the workpiece electric field is set to the ground potential and the electrostatic field is applied by applying a high voltage to the workpiece. And charged paint particles are sprayed from a coating machine and applied to an object to be coated.
[0003]
By the way, when performing electrostatic coating, if the coating machine is too close to the object to be coated, there is a risk of causing dielectric breakdown and sparking.
For this reason, when a dark current flowing between the grid electrode or the coating machine and the object to be coated is detected and the current exceeds a predetermined current value that causes a dielectric breakdown, the dark current is supplied to the coating machine or the grid. High voltage is cut off to prevent spark discharge.
In this case, in the case of the indirect charging method or the direct gun charging method, a high voltage is supplied to each coating machine, and a dark current is controlled by attaching a current detector to each coating machine. Since it is possible to detect the units one by one, the high voltage can be cut off when any one of the coating machines abnormally approaches the object to be coated.
[0004]
[Problems to be solved by the invention]
However, in the case of the work charging method, a high voltage is applied to the work, and at the same time, a plurality of coating machines move closer to or away from the object to be coated. For example, only one coating machine is abnormally close to the object to be coated. The dark current when multiple coating machines are close to the object to be coated within the range that does not cause spark discharge is higher than the dark current when It is difficult to detect that the coating machine has abnormally approached the object to be coated.
In addition, in an automatic coating apparatus that performs non-electrostatic coating, since no electrostatic field is formed between the coating machine and the object to be coated, no spark is generated when the coating machine gets too close to the object to be coated. However, since no dark current is flowing, it is impossible to detect whether the current is abnormally approached by the current value, and the paint adheres when the coating machine gets too close to the workpiece while the coating machine is moving. There is a possibility that the coating failure may occur and the coating machine may collide with the object to be coated while moving.
[0005]
Therefore, the present invention reliably detects that the coating machine has abnormally approached the object to be coated, for example, when performing electrostatic coating or non-electrostatic coating, The technical challenge is to prevent coating defects due to abnormal approach of the machine and collision between the machine and the object to be coated.
[0006]
[Means for Solving the Problems]
In order to solve this problem, the present invention provides a coating machine with a marker that can be distinguished from the background in an automatic coating apparatus that coats the object to be coated while moving the coating machine along the coating surface of the object to be coated. And an object to be coated with the coating machine at the same time and from a position that does not overlap in front and back, and the coating machine abnormally approaches the object to be coated based on an image signal output from the imaging apparatus An image processing device for determining whether or not the image processing device detects the shape of the object to be coated, and the marker attached to the coating machine based on the shape of the object to be coated is no longer on the object to be coated. An abnormal approach area setting means for setting an area that should not be approached as an abnormal approach area, a marker position detecting means for detecting the position of the marker imaged by the imaging device, and the detected marker position is the abnormal approach area When entering the area Characterized by comprising a abnormally close signal outputting means for outputting a normal approach signal.
[0007]
According to the present invention, the painting machine with a marker that can be distinguished from the background and the object to be coated by the painting machine are imaged simultaneously and so as not to overlap each other. The shape of the object to be coated and the position of the marker are detected.
For example, when performing electrostatic coating, based on the detected object shape, an area where a spark is generated when the coating machine approaches the object to be coated is set as an abnormally approaching area and detected. If the abnormal approach signal is output when the position of the marker enters the abnormal approach region, it is possible to detect that the coating machine has abnormally approached by the presence or absence of the output of the abnormal approach signal.
In this case, since the marker attached to the coating machine is detected, the marker position is detected in an extremely short time compared to the case of recognizing the shape of the coating machine based on the information of all image signals. The smaller the marker size, the better.
[0008]
Then, if the high voltage applied to the coating machine or the object to be coated is cut off based on this abnormal approach signal, the high voltage is cut off before the coating machine approaches the object and generates a spark. Thus, the occurrence of sparks is prevented.
In addition to preventing the occurrence of sparks during painting, by arbitrarily setting the abnormal approach area, coating failure due to abnormal approach of the paint machine and collision between the paint machine and the object to be coated can be prevented. Is done.
[0009]
Further, according to another automatic coating apparatus according to the present invention, when electrostatic coating is performed, the moving speed vector of the coating machine at the current coating machine position is calculated based on the marker position detected at predetermined time intervals. The coating machine position is predicted after a predetermined time, and an abnormal approach signal is output when the predicted position enters the abnormal approach area. , Coating failure due to abnormal approach of the coating machine and collision between the coating machine and the object to be coated are prevented.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
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 an image processing procedure thereof.
[0011]
In the automatic coating apparatus 1 of this example, a high voltage generator 2 is connected to a workpiece W such as an automobile body that is insulated and supported, and a coating machine 3 is connected to the ground so that a high voltage is applied to the workpiece W. The workpiece electrification in which the paint sprayed from the coating machine 3 is electrostatically applied to the workpiece W in a state where the coating machine 3 is grounded and an electrostatic field is formed between the coating machine 3 and the workpiece W. A type electrostatic coating device is used.
The coating machine 3 is attached to the tip of the robot arm 5 of the articulated multi-axis control machine 4 installed on both the left and right sides of the conveyor that conveys the coating object, for example, and the coating machine 3 is moved along the side surface of the coating object W. The coating machine 3 is provided with a marker M of a color different from the background in the vicinity of its tip.
[0012]
And the imaging device 6 which images the coating machine 3 and the to-be-coated object W in the same screen is attached to the front or back of the conveyance direction of the to-be-coated object W, and the coating machine 3 is painting normally Thus, imaging is performed from a position where the coating machine 3 and the workpiece W do not overlap each other, and the imaging device 6 determines whether the coating machine 3 has abnormally approached the workpiece W based on the image signal. Is connected to an image processing device 7 that outputs an abnormal approach signal when an abnormal approach occurs, and the image processing device 7 cuts off the high voltage applied to the workpiece W based on the abnormal approach signal. In addition to being connected to the high voltage generator 2 provided with a high voltage cut-off circuit (not shown), it is connected to a grounding switch 8 for releasing the electrostatic charge accumulated in the article W to be grounded.
[0013]
The image processing device 7 detects the shape of the workpiece W, and determines that the region where the marker M attached to the coating machine 3 is closer to the workpiece W based on the shape of the workpiece W An abnormal approach region setting means 9 set as A, a marker position detecting means 10 for detecting the position of the marker M imaged by the imaging device 6 and recognizing it as a coating machine position, and the detected marker position being the abnormal And an abnormal approach signal output means 11 for outputting an abnormal approach signal when entering the approach area A.
Since the marker position detection means 10 detects the marker M attached to the coating machine 3, it takes an extremely short time compared to the case where the pattern recognition of the coating machine 5 is performed based on the information of all image signals. The marker position can be detected with.
[0014]
The above is an example of the configuration of the present invention. Next, its operation will be described with reference to FIG.
When the workpiece W arrives at a predetermined painting start position, image processing by the image processing device 7 is started before the painting is started. First, based on the image input from the imaging device 6 in step 1 (STP1). Thus, an abnormal approach warning area A is set. At this time, the object to be coated W slowly moves toward 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 by performing pattern recognition, and the coating machine is based on this. The limit area where the spark is generated when 3 approaches the workpiece W more than that is set as the abnormal approach area A.
[0015]
Here, the paint is sprayed from the coating machine 3 maintained at the ground potential, and the high voltage is applied to the workpiece W to which the high voltage supplied from the high voltage generator 2 is applied to start electrostatic coating. .
When painting is started, the image signal captured by the imaging device 6 is input to the image device 7 at predetermined time intervals, and whenever the image signal is input in step 2 (STP2), the image signal is input to step 3 (STP3). The position of the marker M attached to the painting machine 3 is detected and recognized as the painting machine position.
In this case, since the marker M attached to the coating machine 3 is detected, the marker position is detected in an extremely short time compared with the case where the pattern recognition of the coating machine 5 is performed based on the information of all image signals. can do.
Next, the process proceeds to step 4 (STP4), and it is determined whether or not the marker M is located in the abnormal approach area A set in step 1 (STP1), and the coating machine 3 enters the abnormal approach warning area A. If not, return to step 2 (STP2) and wait until the next image signal is input. If the position of the marker M enters the abnormal approaching area A, the process proceeds to step 5 (STP5) and abnormal. Output an approach signal.
When an abnormal approach signal is output, the high voltage cut-off circuit in the high voltage generator 2 is activated 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 in the object to be coated is released to the ground, and further, the supply of the paint to the coating machine 3 is stopped and the painting is interrupted.
[0016]
In this example, the case where the abnormal approach area A is set every time the article W arrives at the painting position has been described. However, when the silhouette of the article W changes during painting, every predetermined time. The abnormal approach area A may be updated.
Moreover, when using the coating apparatus which performs non-electrostatic coating as the automatic coating apparatus 1, the area | region of the limit which causes a coating defect when the marker M attached | subjected to the coating machine 3 approaches the to-be-coated article W further, The limit area that collides with the workpiece W when approaching the workpiece W is set as the abnormal approach area A, and when the abnormal approach signal is output, the spraying of the paint is stopped or painted If the machine 3 is stopped or moved backward, coating failure and collision of the painting machine can be prevented.
Furthermore, the marker M is not limited to a colored one, and any one can be adopted as long as it can be distinguished from the background, such as a light emitter or a reflector, but in order to detect the position of the marker M in a short time. The area should be small.
[0017]
FIG. 3 is a schematic explanatory view showing another automatic painting apparatus according to the present invention, and FIG. 4 is a flowchart showing an image processing procedure thereof. In addition, the same code | symbol is attached | subjected about the part which is common in FIG. 1, and detailed description is abbreviate | omitted.
The automatic coating apparatus 21 of this example is configured to predict the position of the coating machine after a predetermined time has elapsed, and the coating machine 3 with the marker M of a color different from the background and the article W to be coated within the same screen. In addition, the image processing device 22 is connected to the image pickup device 6 that picks up images from positions that do not overlap in the front-rear direction.
[0018]
The image processing device 22 detects a shape of the object to be coated W, and generates an area where a spark is generated when the position of the marker M attached to the coating machine 3 is closer to the object to be coated W based on the shape of the object to be coated. An abnormal approach region setting means 23 for setting as an abnormal approach region B, a marker position detecting means 24 for detecting the position of the marker M imaged by the imaging device 6 at predetermined time intervals, and the detected marker position in sequence. Based on the position data storage means 25 to be stored, the current position data stored in the position data storage means 25 and one or more position data detected before, at least the current moving direction and movement of the coating machine 3 A marker position predicting means 26 for calculating a moving speed vector composed of a speed and predicting a marker position after a predetermined time has elapsed; Consisting abnormally close signal outputting means 27 for outputting the abnormal approach signal when the overlapping set abnormal approach region B at 23.
[0019]
FIG. 4 is a flowchart showing a processing procedure in the image processing apparatus 7. When the workpiece W arrives at a predetermined painting start position, image processing by the image processing apparatus 7 is started before painting is started. First, the abnormal approach region B is set based on the image input from the imaging device 6 in step 11 (STP11).
When electrostatic coating is started, the counter is reset to i = 1 in step 12 (STP12), an image signal is input from the imaging device 6 in step 13 (STP13), and the process proceeds to step 14 (STP14). Then, based on the image signal, the position of the marker M attached to the coating machine 3 is detected as the coating machine position, and the process proceeds to step 15 (STP15) to sequentially store the data of the coating machine position.
[0020]
Then, in step 16 (STP16), it is determined whether or not the past two position data has been accumulated. If not, the counter i = 2 is set in step 17 (STP17) and the process returns to step 13 (STP13) to accumulate. If so, the process proceeds to step 18 (STP18).
In step 18 (STP18), 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 of the previously detected Based on the velocity vector V, the marker position D ₃ after the elapse of a predetermined time (for example, 0.01 seconds) is predicted based on the current marker position D ₂ .
[0021]
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 in the abnormal approach region B set in step 11 (STP11). If 3 does not enter the abnormal approach area B, the process returns to step 13 (STP13) and waits until the next image signal is input. If the coating machine 3 enters the abnormal approach area B, step 20 ( The process proceeds to STP20), an abnormal approach signal is output, and the process returns to step 11 (STP11).
[0022]
When the abnormal approach signal is output, the high voltage cutoff circuit in the high voltage generator 2 is activated and the high voltage applied to the workpiece W is cut off at the same time as described above. When the switch 8 is turned on, the electrostatic charge accumulated in the object to be coated is released to the ground, and further, the supply of the paint to the coating machine 3 is stopped and the painting is interrupted.
That is, before the coating machine 3 enters the abnormal approach region B, the supply of high voltage to the coating machine 3 is stopped, and the occurrence of sparks is prevented.
[0023]
In this example, the case where the speed vector is calculated based on the current position data and the past one position data to predict the position of the coating machine 3 has been described. However, the present position data and the past two or more times are calculated. If the acceleration, trajectory, and the like are calculated based on the position data, the position of the coating machine can be predicted more accurately.
Of course, this example can also be applied to an automatic coating apparatus that performs non-electrostatic coating.
[0024]
【The invention's effect】
As described above, according to the present invention, since the marker attached to the coating machine is detected, the time required for recognizing the shape of the coating machine based on the information of all the image signals is extremely short. The marker position can be detected, and when the detected marker position falls within the preset abnormal approach area, an abnormal approach signal is output. In addition to having the effect of reliably detecting this in a short time, the occurrence of sparks can be prevented by cutting off the high voltage applied to the coating machine or the object to be coated based on this abnormal approach signal. If the paint spraying is interrupted, coating failure due to abnormal approach of the coating machine is prevented, and if the coating machine is stopped, the collision with the object to be coated 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 apparatus W ... Coated object 3 ... Coating machine M ... Marker 6 ... Imaging apparatus 7 ... Image processing apparatus 9 ... Abnormal approach area setting means 10 ... Marker position detection means 11 ... abnormal approach signal output means 21 ... automatic coating device 22 ... image processing device 23 ... abnormal approach region setting means 24 ... marker position detection means 25 ... position Data storage means 26 ... marker position prediction means 27 ... abnormal approach signal output means

Claims (2)

In an automatic coating apparatus for coating the object to be coated (W) while moving the coating machine (3) along the coating surface of the object to be coated (W),
An image pickup apparatus that picks up an image of a coating machine (3) with a marker (M) that can be distinguished from the background and an object (W) to be coated by the coating machine (3) from a position that does not overlap in the front and rear. (6) and an image processing device (7) that determines whether or not the coating machine (3) has abnormally approached the article (W) based on the image signal output from the imaging device (6). Prepared,
The image processing device (7) detects the shape of the object to be coated (W), and the marker (M) attached to the coating machine (3) based on the shape of the object to be coated further increases the object to be coated (W). And an abnormal approach area setting means (9) for setting an area that should not be approached as an abnormal approach area (A), and marker position detection for detecting the position of the marker (M) imaged by the imaging device (6) Means (10) and an abnormal approach signal output means (11) for outputting an abnormal approach signal when the detected position of the marker (M) enters the abnormal approach region (A). Automatic painting equipment. In an automatic coating apparatus for coating the object to be coated (W) while moving the coating machine (3) along the coating surface of the object to be coated (W),
An image pickup apparatus that picks up an image of a coating machine (3) with a marker (M) that can be distinguished from the background and an object (W) to be coated by the coating machine (3) from a position that does not overlap in the front and rear. (6) and an image processing device (22) for determining whether or not the coating machine (3) has abnormally approached the article (W) based on the image signal output from the imaging device (6). Prepared,
The image processing device (22) detects the shape of the object to be coated (W), and the marker (M) attached to the coating machine (3) based on the shape of the object to be coated further increases the object to be coated (W). The abnormal approach region setting means (23) for setting the region that should not approach the abnormal approach region (B) and the position of the marker (M) imaged by the imaging device (6) at predetermined time intervals Marker position detection means (24) for detection, position data storage means (25) for sequentially storing detected position data, current position data stored in the position data storage means (25) and before Marker position predicting means (26) for calculating a moving speed vector of the marker (M) at least at the current marker position based on the one or more position data detected in the step and predicting the position of the marker (M) after a predetermined time has elapsed. And the predicted marker position And an abnormal approach signal output means (27) for outputting an abnormal approach signal when the vehicle enters the abnormal approach area (B) set by the abnormal approach area setting means (23). Painting equipment.

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