JP4541509B2 - Application failure detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an application failure detection apparatus that detects application failure of an application material applied to a workpiece using a supply nozzle.
[0002]
[Prior art]
Conventionally, various systems for automatically applying a coating material such as a sealing material or an adhesive to the surface of a workpiece using a robot or the like have been proposed. In this case, the coating material has viscosity, and since this viscosity is greatly affected by temperature, the temperature is usually controlled and the coating operation is performed at a constant temperature. The property changes not only by the temperature of itself but also by the temperature state of the workpiece having the surface to be coated, dirt (attached oil and fat and dust), and surface state (plating, rust).
[0003]
For this reason, a process for detecting the presence or absence of application failure such as application failure is required. For example, Japanese Patent Application Laid-Open No. 10-10051 uses a CCD camera to capture an application state after application is completed and A technique for inspecting whether or not an application-cut portion exists by performing a valuation process is disclosed.
[0004]
In addition to this, a technique has also been proposed in which the application state after completion of application is partially confirmed using a detector.
[0005]
[Problems to be solved by the invention]
However, since any technique detects the presence or absence of application failure after the application operation is completed, the work after completion of the application operation cannot be immediately transferred to the next process, resulting in poor work efficiency.
[0006]
For example, even when a coating failure occurs immediately after the start of the coating operation, the coating operation itself may be wasted because the coating failure cannot be detected until the coating operation is completed. Furthermore, a system that performs image processing using a CCD camera is expensive and cannot be easily adopted.
[0007]
In order to cope with this, it is conceivable to detect the application state after delivering the coating material by moving the detector following the supply nozzle, but the supply nozzle is fixed to the tip of the application robot. In this case, the supply nozzle does not always move linearly, and since it cannot be specified in which direction the supply nozzle moves, it is difficult to accurately follow the supply nozzle with a detector, resulting in poor coating. Detection accuracy becomes a problem.
[0008]
In view of the above circumstances, the present invention can detect application failure almost in real time, can reduce the detection time, and minimizes waste of application work when application failure occurs. An object of the present invention is to provide a possible application defect detection device.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a first application defect detection device according to the present invention includes a supply nozzle that moves relative to a surface to be coated of a workpiece and delivers a coating material to the surface to be coated, and a periphery of the supply nozzle. And a plurality of light emitting units and light receiving units arranged alternately or periodically, and a coating defect for detecting a coating defect of the coating material based on reflected light from the coated surface direction received by the light sensor. and a detection unit, the plurality of light receiving portions is characterized that you have been set so that the detection range of the light receiving portions adjacent wraps.
[0010]
In such a configuration, since the light projecting unit of the light emitting unit member and the light receiving unit of the optical sensor are disposed around the supply nozzle that delivers the coating material to the surface to be coated of the workpiece, it is possible to apply a coating that is out of coating during the coating operation. When a defect occurs, it can be detected in real time.
[0012]
In this case, preferably, 1 ) the light projecting unit and the light receiving unit of the photosensor are coaxially arranged around the supply nozzle.
[0013]
2 ) The application failure detecting unit is connected to a switch unit for sequentially selecting signals photoelectrically converted by the photoelectric conversion units provided in the respective optical sensors.
[0014]
3 ) The optical sensor is an optical fiber sensor.
[0015]
4 ) The application failure detection unit is characterized in that, when the application material is not detected even after a predetermined time has elapsed after the supply of the application material from the supply nozzle is started, it is determined that the application is defective.
[0016]
5 ) The application failure detection unit determines that the application failure is detected when the application material is not detected during delivery of the application material from the supply nozzle.
[0017]
6 ) The supply nozzle moves the supply nozzle relative to the workpiece at least until the light receiving portion of the optical sensor passes through the application end position of the supply nozzle even after the application of the application material is completed.
[0018]
7 ) The light projecting unit and the light receiving unit of the optical sensor are supported by a holding member disposed on the outer periphery of the supply nozzle, and the holding member is slidably supported along the axial direction of the supply nozzle. It is characterized by being.
[0019]
8) In 7 ), the holding member is slidably supported via an elevating mechanism.
[0020]
9 ) The light receiving portion is a light receiving fiber, and the light receiving fiber also serves as a color filter.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described 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.
[0022]
The coating robot 1 includes a free arm 2, and a nozzle holder 2 a that holds a supply nozzle 3 is provided at the tip of the free arm 2. The supply nozzle 3 is connected to a pump unit (not shown), and a coating material such as a sealing material and an adhesive is supplied from the pump unit.
[0023]
Also, as shown in FIGS. 4 and 5, a work w having an application surface w1 to which the application material is applied is placed and fixed on a work bench (not shown), and the application robot 1 is incorporated in advance. The supply nozzle 3 is moved along the application surface w1 of the workpiece w in accordance with the program being executed. As shown in the figure, the coated surface w1 is provided on the periphery of the workpiece w, for example, and the coating material 4 continuously delivered from the supply nozzle 3 is coated with the movement of the universal arm 2. It is applied in a bead shape on w1.
[0024]
As shown in FIGS. 2 and 3, a sensor holding member 5 formed in a ring shape is disposed 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 a nozzle holder 2 a that holds the supply nozzle 3.
[0025]
As shown in FIG. 3B, the sensor holding member 5 includes a light receiving fiber portion 6a as a light receiving portion provided in the optical fiber sensor 6, and a light projecting portion extending from a light source (not shown). The projecting fiber portions 7 are alternately arranged. Note that the interval between the light receiving fiber portions 6a is set so that the detection range between adjacent ones slightly overlaps.
[0026]
Each fiber part 6 a, 7 is arranged in parallel with the supply nozzle 3. Since the tip of the supply nozzle 3 is set so as to deliver the coating material 4 in a state of being substantially perpendicular to the coated surface w1 of the workpiece w, the end surfaces of the fiber portions 6a and 7 are also arranged on the workpiece. It is opposed in a direction substantially perpendicular to w. In this case, the light projecting fiber portions 7 are arranged at intervals so that the projection lights do not interfere with each other.
[0027]
Further, the light projecting fiber portions 7 do not need to be alternately arranged with respect to the light receiving fiber portion 6a, but are arranged with a periodic interval such as every two or three with respect to the light receiving fiber portion 6a. You may do it.
[0028]
FIG. 6 shows the basic configuration of the automatic coating apparatus. As shown in the figure, a photoelectric switch unit 6b as a photoelectric conversion unit is disposed on the emission end side of the light receiving fiber unit 6a provided in each optical fiber sensor 6, and this photoelectric switch unit 6b is connected to the switch unit 8. The detection signal from the switch unit 8 is output to the application failure detection unit 9.
[0029]
Each photoelectric switch unit 6b converts the presence / absence of light input to the light projecting fiber unit 7 into an electrical ON / OFF signal according to the sensitivity adjusted in advance, and outputs the signal to the switch unit 8. In the embodiment, the detection of the application cut portion 4a (see FIGS. 4 and 5) formed by the supply of the coating material 4 from the supply nozzle 3 temporarily stagnation is detected. This is performed using a step with respect to the coating surface w1).
[0030]
That is, normally, the coating material 4 is sticky, and when applied to the coated surface w1 of the workpiece w, a slight rise occurs. Therefore, the sensitivity adjustment is performed using the step between the coated material 4 and the coated surface w1. In addition, the application cut portion 4a is detected.
[0031]
As another aspect, the light receiving fiber portion 6a itself is colored and used as a color filter, so that the photoelectric switch portion 6b is set to be sensitive to a specific color tone or lightness, and the optical fiber sensor 6 is connected to the color fiber. You may make it function as a sensor.
[0032]
That is, when there is a color tone difference or brightness difference between the coated surface w1 and the coating material 4, the detection accuracy may be higher when the color fiber sensor is used than when the normal optical fiber sensor 6 is used. . In such a case, it is possible to simplify the structure and improve the detection accuracy by coloring the light projecting fiber portion 7 itself and causing the normal optical fiber sensor 6 to function as a color fiber sensor.
[0033]
For example, when the workpiece w is a vehicle body, the sheet metal of the vehicle body is silver, and the coating material (sealing material) 4 applied to the vehicle body is blue, or the workpiece w is the front glass of the vehicle, and the outer periphery of the front glass When the coated surface w1 provided on the black ceramic part is a black ceramic part and the coating material (adhesive) 4 applied to the black ceramic part is yellow, the light receiving fiber part 6a is colored with the corresponding lightness or color tone. By doing so, it is possible to detect an application failure based on a brightness difference or a color tone difference.
[0034]
The switch unit 8 is configured by an analog switch that sequentially selects signals from the photoelectric switch units 6b and outputs them serially at a certain time difference.
[0035]
The application failure detection unit 9 starts application failure detection in synchronization with a work start signal from the robot control unit 11. When the application failure detection is started, the ON / OFF signals sequentially output from the switch unit 8 are read, and the presence / absence of the application cut portion 4a is detected based on the ON / OFF signal.
[0036]
When the application failure detection unit 9 detects the application failure portion 4a, it outputs an alarm signal to the alarm means 10 and sends an application operation stop signal to the robot control unit 11 that controls the application robot 1. Output.
[0037]
On the other hand, the robot control unit 11 continuously moves the supply nozzle 3 until the sensor holding member 5 passes the application completion position even after the application operation has been completed normally.
[0038]
Next, the operation of the present embodiment having the above configuration will be described. When the workpiece 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 that is present faces the coated surface w1 of the workpiece w. Since the sensor holding member 5 is fixed to the nozzle holder 2a for holding the supply nozzle 3 via the bracket 5a, the fiber portions 6a and 7 held by the sensor holding member 5 are It always moves integrally with the supply nozzle 3.
[0039]
Next, the robot controller 11 drives a pump unit (not shown) to start feeding 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, an application start signal is output to the application failure detection unit 9.
[0040]
The coating start signal from the coating defect detecting section 9, the robot controller 11 causes the timer is started as a trigger, are sequentially output from the switch unit 8, the ON / OFF signal from the photoelectric switch unit 6b of the optical fiber sensor 6 , Read at a predetermined timing.
[0041]
The projection light from the light projecting fiber portion 7 held by the sensor holding member 5 is emitted to the surface including the coated surface w1 of the workpiece w, and the reflected light enters the light receiving fiber portion 6a of the optical fiber sensor 6, Light is received by the photoelectric switch 6b. At this time, the photoelectric switch 6b uses the step between the surface of the workpiece w and the coating material 4 applied to the coated surface w1, and the sensitivity is adjusted so that an ON signal is output when the swelling of the coating material 4 is detected. ing.
[0042]
Therefore, immediately after the supply of the coating material 4 from the supply nozzle 3 to the coated surface w1 is started, any of the light projecting fiber portions 7 and the corresponding light receiving fiber portions 6a held by the sensor holding member 5 are Since the coating material 4 applied to the surface to be coated w1 has not yet been reached, it is erroneously detected that the coating has been cut off. Therefore, the elapsed time is measured by a timer, and the application of the coating material 4 is started. The time required for the light projecting fiber portion 7 and the corresponding light receiving fiber portion 6a located at the rear of the supply nozzle 3 to pass through the coating start position is timed, and after a predetermined time has elapsed, the detection of coating failure is started. .
[0043]
When the application failure detection is started, the application failure detection unit 9 reads the ON / OFF signal of the photoelectric switch unit 6b of each optical fiber sensor 6 sequentially sent from the switch unit 8, and any one of the optical fiber sensors 6 is read. It is checked whether or not the coating material 4 is detected, and when the coating material 4 is detected by any of the optical fiber sensors 6, that is, when an ON signal is output from any of the optical fiber sensors 6. Continue the coating operation.
[0044]
Then, when the coating operation is finished in a predetermined manner, the timer is started again, and any light projecting fiber portion 7 held by the sensor holding member 5 and the corresponding light receiving fiber portion are held at the application work end position of the coating material 4. A sufficient time is measured until 6a passes, during which time the supply nozzle 3 runs idle, and after a predetermined time has elapsed, the coating robot 1 is stopped, the coating operation is completed, and the free arm 2 is in a predetermined standby state. Return to position.
[0045]
On the other hand, when the ON signal is not detected from any of the photoelectric switch sections 6b after the set time has elapsed after the start of the coating work, or when the OFF signals are detected from all the photoelectric switch sections 6b during the coating work, or When OFF signals are detected from all the photoelectric switch sections 6b during the idle time after the coating operation is completed, it is determined that the coating has run out, the alarm means 10 is driven to notify the operator of the coating failure, and the robot An out-of-application signal is output to the control unit 11.
[0046]
Then, the robot controller 11 immediately stops the coating robot 1 to stop the coating operation and return the free arm 2 to the standby position.
[0047]
As described above, in this embodiment, the application work is immediately stopped when the application failure is detected. Therefore, the waste of the application work can be minimized and the work efficiency can be improved. In addition, since the optical fiber sensor 6 is disposed around the supply nozzle 3, it is possible to accurately detect a coating defect regardless of which direction the supply nozzle 3 moves. Will improve.
[0048]
FIG. 7 is a bottom view of the sensor holding member according to the 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. However, in the present embodiment, the light receiving portions corresponding to each other with respect to the sensor holding member 12. The fiber part 6a and the light projecting fiber part 7 are arranged coaxially in the radial direction with the supply nozzle 3 as the center, and the operational effects are the same as in the first embodiment.
[0049]
FIG. 8 shows an enlarged view of the tip of the coating robot according to the third embodiment of the present invention. In the present embodiment, the sensor holding member 13 that holds the light receiving fiber portion 6a and the light projecting fiber portion 7 is held with respect to the nozzle holder 2a via the elevating mechanism 14 so as to be able to advance and retract in the axial direction.
[0050]
That is, when the rotary actuator 15 fixed to the nozzle holder 2a of the lifting mechanism 14 is driven, the rotary lever 15a connected to the rotary actuator 15 rotates in the direction of the arrow shown in FIG. The sensor holding member 13 is pulled upward via the link arm 16.
[0051]
A support arm 17 has a base portion fixed on both sides of the sensor holding member 13 which is perpendicular to the link arm 16, and an upper portion thereof is inserted into a guide rail 18 fixed on both sides of the nozzle holder 2a. .
[0052]
Therefore, when the sensor holding member 13 is pulled upward via the link arm 16, the sensor holding member 13 is supported by the support arm 17 and the guide rail 18 and remains coaxial with the supply nozzle 3. , Slide upwards.
[0053]
By using the elevating mechanism 14, for example, when the tip of the supply nozzle 3 is cleaned, the tip of the supply nozzle 3 can be easily exposed. In addition, when the lifting mechanism 14 is interlocked with the operation of the coating robot, for example, when the coating operation is finished, the lifting mechanism 14 is operated to retract the sensor holding member 13 upward, so that there are other parts around. In addition, when the supply nozzle 3 is moved to a narrow part, interference between these members and the sensor holding member 13 can be avoided.
[0054]
The present invention is not limited to the above-described embodiments. For example, the optical fiber sensor is held by the sensor holding member 5 in a state where the light projecting fiber portion 7 and the light receiving fiber portion 6a are configured in pairs, and each light The parallel light may be alternatively and sequentially projected from the light projecting fiber of the sensor, and the corresponding photoelectric conversion unit may be driven in synchronization therewith. By doing in this way, interference between sensors is avoided and the coating-out detection accuracy improves.
[0055]
In the sensor holding member 5 according to the present embodiment, the light projecting fiber and the light receiving fiber are disposed in a ring shape, but may be disposed in a polygonal shape such as a quadrangle or a hexagon.
[0056]
Furthermore, the sensor holding member 13 in the third embodiment may have a structure that can be manually moved up and down without using the elevating mechanism 14.
[0057]
【The invention's effect】
As described above, according to the present invention, it is possible to detect the occurrence of a coating failure almost in real time, to shorten the detection time, and to minimize the waste of coating work when a coating failure occurs. Excellent effects such as being able to be limited.
[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 a supply nozzle. FIG. 3 is a side view of a sensor holding member. FIG. 4 is a perspective view showing the relationship between the supply nozzle and the sensor holding member during the application operation. FIG. 5 is a plan view showing the relationship between the supply nozzle and the sensor holding member during the application operation. FIG. 6 is a block diagram showing the basic configuration of the automatic coating apparatus. FIG. 7 is a bottom view of a sensor holding member according to the second embodiment. FIG. 8A is a tip of a coating robot according to the third embodiment. Enlarged view of the part, bottom view of (b) (a) 【Explanation of symbols】
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 Projection fiber part (projection part)
8 Switch unit 9 Application failure detection unit 5, 12, 13 Sensor holding member 14 Elevating mechanism w Work w1 Surface to be applied

Claims (10)

A supply nozzle that moves relative to the surface to be coated of the workpiece and delivers the coating material to the surface to be coated;
A plurality of light projecting portions and light receiving portions of the optical sensor disposed alternately or periodically around the supply nozzle;
A coating failure detection unit that detects a coating failure of the coating material based on reflected light from the coated surface direction received by the optical sensor ;
The plurality of coating defect detecting device receiving unit, characterized that you have been set so that the detection range of the light receiving portions adjacent wraps.   2. The coating defect detection device according to claim 1, wherein the light projecting unit and the light receiving unit of the optical sensor are arranged coaxially around the supply nozzle.   2. The defective coating according to claim 1, wherein the defective coating application unit is connected to a switch unit for sequentially selecting signals photoelectrically converted by photoelectric conversion units provided in the respective optical sensors. Detection device. Coating failure detecting apparatus according to any one of claim 1 to 3, wherein the optical sensor is an optical fiber sensor. After dispensing of the coating material from the supply nozzle is initiated in the coating defect detecting section, when after a predetermined time is also not detected the coating material is as claimed in claim 1-4, characterized in that to determine that poor coating The coating defect detection apparatus according to any one of the above. Poor coating according to any one of claim 1 to 5 is the coating defect detecting section when not detected the coating material during dispensing of the coating material from the supply nozzle, characterized in that to determine that poor coating Detection device. The supply nozzle moves the supply nozzle relative to the workpiece until the light receiving portion of the optical sensor passes at least the application end position of the supply nozzle even after the application of the application material is completed. The application defect detection device according to any one of to 6 . The light projecting unit and the light receiving unit of the optical sensor are supported by a holding member disposed on the outer periphery of the supply nozzle, and the holding member is supported slidably along the axial direction of the supply nozzle. The coating defect detection device according to any one of claims 1 to 4 . 9. The application failure detection apparatus according to claim 8, wherein the holding member is slidably supported via an elevating mechanism. A said light receiving portion receiving fibers, coating failure detecting apparatus according to any one of claims 1 to 9, characterized in that the light receiving fiber also serves as a color filter.

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