JP2002045755A - Coating failure detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a coat discontinuity in a real time mode during coating operation by a coating robot. SOLUTION: A ring-shaped sensor retaining member 5 is arranged on the periphery of a supply nozzle 3 retained by the coating robot, and a plurality of light receiving fiber parts for optical fiber sensors are arranged on the sensor retaining member 5. The periphery of the supply nozzle 3 is monitored using the optical fiber sensors 6, during the coating operation, when the supply nozzle 3 is moved while applying a coating material 4 fed from the nozzle 3 along the area w1 to be coated of a work (w). When the coating material 4 applied to the area w1 is not detected by either of the optical fiber sensors, it is judged that the coat discontinuity exists and then the coating robot is stopped and the coating operation is suspended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating defect detecting apparatus for detecting a coating defect of a coating material applied to a work using a supply nozzle.

[0002]

2. Description of the Related Art Conventionally, various systems have been proposed for automatically applying a coating material such as a sealing material or an adhesive to the surface of a work by using a robot or the like. in this case,
Since the coating material has viscosity, and this viscosity is greatly affected by the temperature, the temperature is usually controlled and the coating operation is performed at a constant temperature. Not only the temperature but also the temperature of the work having the surface to be coated, dirt (fouling oil and dust), and the surface state (plating, rust) change.

[0003] Therefore, a step of detecting the presence or absence of coating failure such as coating shortage is required.
Japanese Patent Application Laid-Open No. 051 discloses a technique in which a coating state after coating is completed is imaged using a CCD camera, the image is binarized, and it is checked whether or not the coating is cut off. .

[0004] In addition, there has been proposed a technique for partially confirming the coating state after the completion of coating using a detector.

[0005]

However, since all of the techniques detect the presence or absence of a coating failure after the completion of the coating operation, the workpiece after the completion of the coating operation cannot be immediately transferred to the next process. , Work efficiency is poor.

[0006] Even if a coating failure occurs immediately after the start of the coating operation, for example, the coating operation is not completed until the coating operation is completed.
Since the coating failure cannot be detected, the coating operation itself may be wasted. Further, a system for performing image processing using a CCD camera is expensive and cannot be easily adopted.

To cope with this, it is conceivable to move the detector following the supply nozzle and detect the coating state after supplying the coating material almost in real time. If it is fixed in
Since the supply nozzle does not always move linearly and it is not possible to specify in which direction the supply nozzle moves, it is difficult to accurately follow the supply nozzle with a detector, and the detection accuracy of coating failure is a problem. Becomes

In view of the above circumstances, the present invention can detect a coating defect almost in real time, can shorten the detection time, and minimizes the waste of the coating operation when the coating defect occurs. It is an object of the present invention to provide an application failure detecting device capable of performing the following.

[0009]

In order to achieve the above object, a first coating defect detecting apparatus according to the present invention relatively moves along a coating surface of a work and delivers a coating material to the coating surface. A supply nozzle, a plurality of light projecting units disposed around the supply nozzle and a light receiving unit of the optical sensor, and a coating defect of the coating material based on reflected light from the coating surface direction received by the optical sensor. And a coating defect detecting unit for detecting the defective coating.

In such a configuration, since the light projecting portion of the light emitting portion member and the light receiving portion of the optical sensor are arranged around the supply nozzle for supplying the coating material to the surface to be coated of the work, the coating is not performed during the coating operation. And the like, can be detected in real time.

In this case, preferably, 1) the light emitting section and the light receiving section of the optical sensor are alternately or periodically arranged around the supply nozzle.

2) The light emitting section and the light receiving section of the optical sensor are coaxially arranged around the supply nozzle.

[0013] 3) A switch unit for sequentially and selectively selecting signals photoelectrically converted by a photoelectric conversion unit provided in each of the optical sensors is connected to the coating defect detection unit.

4) The optical sensor is an optical fiber sensor.

5) The application failure detecting section determines that the application failure is detected when the application material is not detected even after a predetermined time has elapsed after the supply nozzle starts to supply the application material.

6) The application defect detecting section determines that the application defect is detected when the application material is not detected during the supply of the application material from the supply nozzle.

7) The supply nozzle moves the supply nozzle relative to the workpiece even after the application of the coating material is completed, at least until the light receiving section of the optical sensor has passed the application end position of the supply nozzle. And

8) The light projecting section and the light receiving section of the optical sensor are supported by a holding member arranged on the outer periphery of the supply nozzle, and the holding member is slidable along the axial direction of the supply nozzle. It is characterized by being supported.

9) In 8), the holding member is slidably supported via an elevating mechanism.

10) The light receiving section is a light receiving fiber,
This light receiving fiber is characterized in that it also serves as a color filter.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 6 show a first embodiment of the present invention. FIG. 1 shows a schematic configuration of a coating robot.

The coating robot 1 has a free arm 2, and a tip end of the free arm 2 is provided with a nozzle holder 2 a for holding a supply nozzle 3. A pump unit (not shown) is connected to the supply nozzle 3.
A coating material such as a sealing material and an adhesive is supplied from the pump unit.

As shown in FIGS. 4 and 5, a work w having a surface w1 to be coated with the coating material is mounted and fixed on a work bench (not shown). The supply nozzle 3 is moved along the application surface w1 of the work w in accordance with a program incorporated in advance.
As shown in the figure, the application surface w1 is provided, for example, on the periphery of the work w, and the application material 4 continuously supplied from the supply nozzle 3 is applied to the application surface by the movement of the free arm 2. w1 is applied in a bead shape.

As shown in FIGS. 2 and 3, a ring-shaped sensor holding member 5 is provided on the outer periphery of the supply nozzle 3. A bracket 5 a is fixed to one side of the sensor holding member 5, and the bracket 5 a
Is fixed to the nozzle holder 2a for holding the nozzle.

As shown in FIG. 3B, the sensor holding member 5 has a light receiving fiber portion 6a as a light receiving portion provided on the optical fiber sensor 6, and a light projecting from a light source (not shown). Light emitting fiber portions 7 as light portions are alternately arranged. Note that the intervals between the light receiving fiber portions 6a are set so that the detection ranges of the adjacent ones slightly overlap.

Each of the fiber portions 6a and 7 is disposed in parallel with the supply nozzle 3. Since the tip of the supply nozzle 3 is set so as to supply the coating material 4 in a state of being substantially opposed to the coating surface w1 of the work w in a direction perpendicular to the coating surface w1, the end faces of the fiber portions 6a and 7 are also formed. It is installed substantially perpendicular to w. In this case, the light projecting fiber sections 7 are arranged at intervals such that the projected lights do not interfere with each other.

The light projecting fiber section 7 is connected to the light receiving fiber section 6.
It is not necessary to arrange them alternately with respect to the light receiving fiber part 6a.

FIG. 6 shows the basic configuration of the automatic coating apparatus. As shown in the figure, a photoelectric switch section 6b as a photoelectric conversion section is disposed on the emission end side of the light receiving fiber section 6a provided in each optical fiber sensor 6, and this photoelectric switch section 6b
Are connected to the switch unit 8, and a detection signal from the switch unit 8 is output to the coating failure detection unit 9.

Each photoelectric switch section 6b converts the presence or absence of light input into the light projecting fiber section 7 into an electrical ON / OFF signal in accordance with the sensitivity adjusted in advance, and outputs the signal to the switch section 8. In the present embodiment, the detection of the cut-out portion 4a (see FIGS. 4 and 5) formed by the temporary interruption of the supply of the coating material 4 from the supply nozzle 3 is performed.
And the surface of the workpiece w (and the surface to be coated w1).

That is, since the coating material 4 is usually sticky and slightly swells when it is applied to the surface w1 to be coated of the work w, the step between the coating material 4 and the surface w1 to be coated is used. The sensitivity is adjusted in such a manner as to detect the cut-out portion 4a.

As another mode, the light receiving fiber section 6a
By coloring itself and using it as a color filter, the photoelectric switch unit 6b may be set to respond to a specific color tone or brightness, and the optical fiber sensor 6 may function as a color fiber sensor.

That is, when there is a color difference or a lightness difference between the coating surface w1 and the coating material 4, the detection accuracy is higher when the color fiber sensor is used than when the ordinary optical fiber sensor 6 is used. There are cases. In such a case, the light projecting fiber unit 7 itself is colored, and the normal optical fiber sensor 6 functions as a color fiber sensor.
The structure can be simplified and the detection accuracy can be improved.

For example, when the work w is a car body, the sheet metal of the car body is silver, and the coating material (sealing material) 4 applied to the car body is blue, or the work w is the front glass of the car, and When the coating surface w1 provided on the outer periphery of the glass is a black ceramic portion, and the coating material (adhesive) 4 applied to the black ceramic portion is yellow, the light receiving fiber portion 6a has a corresponding lightness or brightness. By coloring with a color tone, defective coating can be detected based on a difference in lightness or a difference in color tone.

The switch section 8 is connected to each of the photoelectric switch sections 6.
An analog switch which selects one of the signals from b sequentially and outputs it serially with a certain time difference.

The application failure detecting section 9 is provided with a robot controller 11
The application failure detection is started in synchronization with the work start signal from. When the application failure detection is started, an ON / OFF signal sequentially output from the switch unit 8 is read, and the ON / O signal is read.
Based on the FF signal, the presence / absence of the application cutout 4a is detected.

When the application defect detecting section 9 detects the application cutout section 4a, it outputs an alarm signal to the alarm means 10 and sends an alarm signal to the robot control section 11 for controlling the application robot 1. Outputs stop signal.

On the other hand, the robot controller 11 continuously moves the supply nozzle 3 even after the coating operation has been completed normally, until the sensor holding member 5 passes the coating completion position.

Next, the operation of the present embodiment having the above configuration will be described. When the work w is placed on a work bench (not shown), the robot controller 11 operates the coating robot 1 according to a preset program, and is fixed to the tip of the free arm 2. The supply nozzle 3 facing the surface to be coated w1 of the work w. Since the sensor holding member 5 is fixed to the nozzle holder 2a holding the supply nozzle 3 via the bracket 5a, each of the fiber portions 6a and 7 held by the sensor holding member 5 It always moves integrally with the supply nozzle 3.

Next, the robot controller 11 drives a pump unit (not shown) to start supplying the coating material 4 from the supply nozzle 3, and moves the supply nozzle 3 along the surface to be coated w1. At the same time, the coating defect detection unit 9
And outputs a coating start signal.

The coating defect detecting section 9 includes a robot control section 11
The start of the timer is triggered by the application start signal from the controller, and the ON / O output from the photoelectric switch unit 6b of each optical fiber sensor 6 sequentially output from the switch unit 8.
The FF signal is read at a predetermined timing.

The light projected from the light projecting fiber portion 7 held by the sensor holding member 5 is emitted to the surface of the work w including the coated surface w1, and the reflected light is sent to the light receiving fiber portion 6a of the optical fiber sensor 6. The incident light is received by the photoelectric switch unit 6b. At this time, the sensitivity of the photoelectric switch 6b is adjusted so as to output an ON signal when the rise of the coating material 4 is detected by utilizing a step between the surface of the work w and the coating material 4 applied to the coating surface w1. ing.

Therefore, immediately after the supply of the coating material 4 from the supply nozzle 3 to the surface to be coated w1 is started, any one of the light projecting fiber portions 7 held by the sensor holding member 5 and the corresponding light receiving fiber The section 6a does not yet reach the application material 4 applied to the application surface w1, and thus erroneously detects that the application has run out. Therefore, the elapsed time is measured by a timer, and after the application of the application material 4 is started, A sufficient time is passed for the light projecting fiber portion 7 and the corresponding light receiving fiber portion 6a located behind the supply nozzle 3 of the sensor holding member 5 to pass the coating start position. To start.

When the application shortage detection is started, the application failure detection section 9 reads the ON / OFF signal of the photoelectric switch section 6b of each optical fiber sensor 6 sequentially sent from the switch section 8, and detects any one of the lights. It is checked whether or not the coating material 4 is detected by the fiber sensor 6, and when the coating material 4 is detected by any of the optical fiber sensors 6, that is, an ON signal is output from any of the optical fiber sensors 6. If so, the application operation is continued.

When the application operation is completed in a predetermined manner, the timer is started again, and the application operation end position of the application material 4 is set to any one of the light projecting fiber portions 7 held by the sensor holding member 5 and the corresponding position. A sufficient time is measured until the light-receiving fiber portion 6a passes. During this time, the supply nozzle 3 is idled, and after a predetermined time has elapsed, the coating robot 1 is stopped, and the coating operation is completed and the free arm is stopped. 2 Return to the predetermined standby position.

On the other hand, when the ON signal is not detected from any of the photoelectric switch units 6b after the set time has elapsed after the start of the coating operation, or the OFF signal is detected from all the photoelectric switch units 6b during the coating operation. At the time, or when the OFF signals are detected from all the photoelectric switch sections 6b during the idle running time after the end of the coating operation, it is determined that the coating has run out and the alarm means 10 is driven to notify the worker of the coating defect. At the same time, it outputs an out-of-coating signal to the robot controller 11.

Then, the robot controller 11 immediately stops the coating robot 1, stops the coating operation, and returns the free arm 2 to the standby position.

As described above, in the present embodiment, the application operation is immediately stopped when an out-of-application is detected, so that the waste of the application operation can be minimized and the efficiency of the operation can be improved. it can. Further, since the optical fiber sensor 6 is disposed around the supply nozzle 3, it is possible to accurately detect a coating defect even if the supply nozzle 3 moves in any direction, and to detect a coating defect detection accuracy. Is improved.

FIG. 7 shows a bottom view of a sensor holding member according to a second embodiment of the present invention. In the first embodiment, the light receiving fiber portions 6a and the light projecting fiber portions 7 corresponding to each other are alternately arranged on the sensor holding member. The fiber portion 6a and the light projecting fiber portion 7 are arranged coaxially in the radial direction with the supply nozzle 3 as the center, and the operation and effect are the same as in the first embodiment.

FIG. 8 is an enlarged view of the tip of a coating robot according to a third embodiment of the present invention. In the present embodiment, the sensor holding member 13 holding the light receiving fiber portion 6a and the light projecting fiber portion 7 is held by the nozzle holder 2a via the elevating mechanism 14 so as to be able to advance and retreat in the axial direction.

That is, when the rotary actuator 15 fixed to the nozzle holder 2a of the elevating mechanism 14 is driven, the rotary lever 15a connected to the rotary actuator 15 moves in the direction of the arrow shown in FIG. Rotate,
The sensor holding member 13 is pulled upward via the link arm 16.

The link arm 1 of the sensor holding member 13
The base of the support arm 17 is fixed on both sides perpendicular to the direction 6, and the upper part thereof is inserted into guide rails 18 fixed on both sides of the nozzle holder 2a.

Therefore, when the sensor holding member 13 is pulled upward via the link arm 16, the sensor holding member 13 is coaxial with the supply nozzle 3 while being supported by the support arm 17 and the guide rail 18. Slide upwards while maintaining.

By using the lifting mechanism 14, for example, when cleaning the tip of the supply nozzle 3, the tip of the supply nozzle 3 can be easily exposed. In addition, when the elevating mechanism 14 is operated in conjunction with the operation of the coating robot, for example, when the coating operation is completed, the elevating mechanism 14 is operated to retract the sensor holding member 13 upward, so that there is another component around. Also, when the supply nozzle 3 is moved to a narrow portion, interference between these members and the sensor holding member 13 can be avoided.

The present invention is not limited to the above embodiments. For example, an optical fiber sensor
And the light receiving fiber portion 6a are held by the sensor holding member 5 in a paired state, and parallel light beams are sequentially and selectively emitted from the light emitting fibers of the respective optical sensors, and the corresponding light beams are synchronously provided. The photoelectric conversion unit may be driven.
By doing so, interference between the sensors is avoided, and the detection accuracy of the application out is improved.

The sensor holding member 5 according to the present embodiment
Although the light-emitting fiber and the light-receiving fiber are arranged in a ring shape, they may be arranged in a polygon such as a square or a hexagon.

Further, the sensor holding member 13 in the third embodiment may have a structure which can be moved up and down manually without using the elevating mechanism 14.

[0057]

As described above, according to the present invention,
It is possible to detect the occurrence of coating failure almost in real time, shorten the detection time, and minimize the waste of coating work when coating failure occurs. Is played.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a coating robot according to a first embodiment.

FIG. 2 is an enlarged view around the supply nozzle.

FIG. 3A is a side view of the sensor holding member, FIG.
(A) Bottom view

FIG. 4 is a perspective view showing a relationship between a supply nozzle and a sensor holding member during a coating operation.

FIG. 5 is a plan view showing a relationship between a supply nozzle and a sensor holding member during the coating operation.

FIG. 6 is a block diagram showing a basic configuration of the automatic coating apparatus.

FIG. 7 is a bottom view of a sensor holding member according to a second embodiment.

8 (a) is an enlarged view of a tip portion of a coating robot according to a third embodiment, and FIG. 8 (b) is a bottom view of (a).

[Explanation of symbols]

 Reference Signs List 3 supply nozzle 4 coating material 6 optical fiber sensor (optical sensor) 6a light receiving fiber part (light receiving part) 6b photoelectric switch part (photoelectric conversion part) 7 light emitting fiber part (light emitting part) 8 switch part 9 coating defect detecting part 5 , 12, 13 Sensor holding member 14 Elevating mechanism w Work w1 Coating surface

Claims (11)

[Claims] 1. A supply nozzle for relatively moving along a surface to be coated of a workpiece and supplying a coating material to the surface to be coated, a plurality of light emitting units disposed around the supply nozzle and light receiving by an optical sensor. A coating defect detecting unit that detects a coating defect of the coating material based on reflected light from the coating surface direction received by the optical sensor. 2. The coating defect detecting apparatus according to claim 1, wherein said light projecting section and said light receiving section of said optical sensor are alternately or periodically arranged around said supply nozzle. 3. The coating defect detecting device according to claim 1, wherein said light projecting section and said light receiving section of said optical sensor are coaxially arranged around said supply nozzle. 4. A switch unit for sequentially selecting one of signals photoelectrically converted by a photoelectric conversion unit provided in each of the optical sensors is connected to the coating defect detection unit. 2. The coating defect detection device according to 1. 5. The coating defect detecting device according to claim 1, wherein said optical sensor is an optical fiber sensor. 6. The application failure detecting unit determines that the application failure is detected if the application material is not detected even after a predetermined time has elapsed after the supply nozzle starts supplying the application material. Item 6. The coating defect detection device according to any one of Items 1 to 5. 7. The application failure detecting unit according to claim 1, wherein said application failure is determined when said application material is not detected during delivery of said application material from said supply nozzle. Coating failure detection device. 8. The supply nozzle moves the supply nozzle relative to the workpiece even after the application of the coating material has been completed, at least until the light receiving portion of the optical sensor has passed the application end position of the supply nozzle. The coating defect detecting device according to claim 1. 9. The light emitting section and the light receiving section of the optical sensor are supported by a holding member disposed on the outer periphery of the supply nozzle, and the holding member is slidable along the axial direction of the supply nozzle. 6. A support according to claim 1, wherein
An application failure detection device according to any one of the above. 10. The coating defect detecting device according to claim 9, wherein said holding member is slidably supported via an elevating mechanism. 11. The coating defect detecting apparatus according to claim 1, wherein said light receiving section is a light receiving fiber, and said light receiving fiber also serves as a color filter.