JPH0451901Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention uses a playback type robot or the like to apply a viscous fluid material such as a sealer to a member to be coated such as an automobile body panel. The present invention relates to a viscous fluid material application detection device that immediately detects the state.

(Prior Art) Recently, for example, in the assembly process of automobiles, the work of applying sealant to car body panels is performed using a playback type robot controlled by an external control device, using a nozzle of a coating gun attached to its hand. By teaching so that the tip moves along a predetermined trajectory with respect to the member to be coated, and controlling the hand so that it passes through the taught trajectory during the coating operation,
It has become common practice to apply sealant to predetermined positions on vehicle body panels.

By the way, in order to use a moving device such as a playback robot to perform work that requires relatively high precision, such as sealing work, it is necessary to improve the repeatability and teaching precision of the robot itself, and the workpiece to be coated (workpiece). ) It is necessary to consider errors based on positioning accuracy, etc., as well as errors between works.

Therefore, a detection device using a one-dimensional image sensor, a two-dimensional image sensor, etc. that approaches the coating gun and images and detects the state of sealant application by the coating gun is attached to the robot's hand, and the detection results are used to detect the coating state. 6th part to correct the position of the coating gun
A viscous fluid material application detection device as shown in the figure is being developed.

As shown in the figure, this device has a coating gun 3 attached to the lower end surface of a cylindrical holder 2 supported at the tip of an arm 1 of a playback type robot instead of a hand.
and a detection device 4 are provided.

The coating gun 3 has a fixed shaft 5 fixed to the holder 2.
The nozzle 6 is fixed to the lower part of the nozzle 6 so that its central axis coincides with the center axis of the nozzle.
It is blown out from the tip and applied in a linear manner onto the panel 8 which is the member to be coated. 9 is the applied sealer material.

The detection device 4 has a ball bearing 1 on a fixed shaft 5.
A photographing lens 13 and an illumination lamp 14 are attached to the lower surface of the case 12, which is rotatably attached via the lens 1. A line sensor 15 that converts into an electric signal depending on brightness and darkness, and a circuit board 16 including a drive circuit thereof, a signal processing circuit, etc. are provided. This photographing lens 13, line sensor 15, and its driving circuit constitute a video camera.

Furthermore, on the side of the case 12, there is a
A DC motor 17 and a tachometer generator 18 for detecting its rotation are attached. And this
The rotation of the DC motor 17 causes the entire detection device 4 to rotate around a fixed shaft 5.
This DC motor 17 is controlled by the control panel 10 via a connector 21 and a cord 22.

The detection device 4 configured as described above detects an error between the application trajectory of the sealer material taught to the robot in advance and the application trajectory of the sealer material currently being applied, and corrects the error. The quality of the application width of the sealer material 9 is determined.

(Problems to be Solved by the Invention) However, in such a conventional viscous fluid material application detection device, the DC control device rotates the detection device 4 based on a signal output from the control device 10.
Since the response speed (gain) of the motor 17 was always constant regardless of the application trajectory of the sealer material,
As shown in FIG. 4, in a curved section where the sealer application trajectory changes suddenly, the relationship between the imaging line S shown in the figure and the application trajectory is significantly different from that in a straight section. In order to maintain the width detection evaluation constant, the tracking position of the detection device 4 must be rapidly corrected, and if the response speed is slow, the application trajectory may go outside the imaging line S. , the detection device 4 may lose track of the object to be tracked.

In addition, if the response speed of the DC motor 17 is increased so that the tracking position of the detection device 4 can be rapidly corrected even in parts where the sealer application trajectory changes suddenly, the response speed of the DC motor 17 can be increased.
Since it reacts sensitively to minute dust and scratches existing in the imaging line S, there is a problem that the tracking control of the detection device 4 loses stability and the detection device 4 loses the original tracking position. Ta.

The present invention has been made in view of such conventional problems, and is based on a DC motor that rotates the detection device 4.
By changing the response speed of the motor 17 according to the application trajectory of the sealer material, the detection device 4 can always be set at the optimal tracking position regardless of the application trajectory of the sealer material. An object of the present invention is to provide a coating detection device.

(Means for Solving the Problems) In order to achieve the above object, the present invention moves the workpiece along a predetermined work trajectory based on signals from an external control device. A viscous fluid material application detection device comprising a moving device equipped with a coating gun that applies a viscous fluid material such as a sealer material, and a detection device that images and detects the state of application of the viscous fluid material by the coating gun, wherein the detection device is attached to the coating gun so as to be rotatable about its nozzle center axis, and a drive device is provided to rotate the detection device according to the coating posture of the coating gun, and the detection device is rotated according to the working trajectory. The present invention is characterized in that a control means for changing the response speed of the drive device is connected to the drive device.

(Function) By configuring as described above, the detection device 4
The DC motor 17, which is a driving device that rotates the The control means 10 that changes the response speed is slowed down in a straight line portion of the coating trajectory, and increased in a curved portion of the coating trajectory. The stability and responsiveness of the tracking control of the detection device 4 in that part are improved, and the detection device 4 can always maintain an optimal tracking position regardless of the sealer application trajectory.

(Example) Below, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows a schematic configuration diagram of a viscous fluid material application detection device according to the present invention.

As shown in the figure, this device has a cylindrical holder 2 at the tip of the arm 1 of the robot, which is driven by a DC motor 17 as a drive device connected to an external control device 25 via a cord 24. is pivotally supported, and a coating gun 3 and a detection device 4 are provided on the lower end surface thereof.

The coating gun 3 has a fixed shaft 5 fixed to the holder 2.
The nozzle 6 is fixed to the lower part of the nozzle 6 so that its central axis coincides with the center axis of the nozzle 6, and a sealant 9 is supplied under pressure from a sealant supply source (not shown) through a hose 7, and is blown out from the tip of the nozzle 6 to form a material to be coated. It is applied in a linear manner onto the panel 8.

The detection device 4 also includes a case 12 rotatably attached to the fixed shaft 5 via a ball bearing 11.
A photographic lens 13 and an illumination lamp 14 are attached to the bottom surface, and inside is a line sensor that converts the image formed on the panel 8 by the photographic lens 13 into an electric signal according to its brightness. A circuit board for the drive circuit and signal processing circuit is provided.
This photographing lens 13, line sensor 15, and its driving circuit constitute a video camera.

Furthermore, on the side of the case 12, there is a
A DC motor 17 and a tachometer generator 18 for detecting its rotation are attached. And this
The rotation of the DC motor 17 causes the entire detection device 4 to rotate around a fixed shaft 5.
This DC motor 17 is controlled by a control panel 10, which is a control means, via a connector 21, a cord 22, and a cord 26.

The control panel 10 and the external control device 25 are
They are connected by a cord 23, and a position signal of the nozzle 6 is output from the external control device 25 to the control panel 10.

The operation of this embodiment will be explained below.

The robot having the arm 1 connects the tip of the nozzle 6 of the coating gun 3 attached to the tip of the robot to the panel 8.
The arm 1 is taught to move along a predetermined work trajectory, and the arm 1 is moved according to a command from the external control device 25.
Applying gun 3 to the inside by a certain distance from the panel end 8a
The sealer material 9 is applied by the following steps.

The rear of the nozzle 6 is illuminated by an illumination lamp 14, and an image of an imaging line S set to intersect with the linear sealer material 9 immediately after application is captured by a video camera comprising a photographing lens 13, a line sensor 15, etc. The width of the applied sealer material 9 is detected based on the video signal, and the width of the applied sealer material 9 is determined. Depending on the coating posture of the coating gun 3, so that they intersect at a certain angle.
Drive the DC motor 17 to connect the detection device 4 to the nozzle 6
Rotate around the central axis of.

FIG. 2 is a block diagram showing an example of a signal processing circuit for determining the application state of the sealer material and correcting the position of the detection device, and operates as follows. This effect will be explained below with reference to FIGS. 3 to 5.

A line sensor 15 in which a large number of solid-state image sensing devices (CCD devices, etc.) are arranged in a straight line receives clock pulses for transfer and reading from a line sensor drive circuit 30.
The imaging line S (point A-B) shown in FIGS. 4 and 5 is supplied with a refresh pulse etc. for each frame.
One frame of video signal a as shown in FIG.

This video signal a is input to a fixed threshold binarization circuit 31 and is compared with a fixed threshold level b as shown in FIG. Obtain a binarized signal.

Since this signal c rises slightly later (inside) than the follow-up point p at the panel edge, the panel edge detection counter 32 synchronizes it with the readout pulse from the line sensor drive circuit 30 at the same time as scanning of one frame starts. The clock pulse cp shown in FIG. 3C, which is generated as shown in FIG. To detect.

The count value of this panel edge detection counter 32 is inputted to a shift detector 33 using, for example, a subtracter, and is determined as a pulse count value corresponding to a predetermined distance between A and P set in advance in the data register 34. The amount of deviation is detected by comparison.

The D/A converter 35 converts a digital value outputted from the deviation detector 33 into a positive or negative analog signal having a polarity and magnitude depending on the direction and amount of deviation of the follow-up point P.

The level of the analog signal output from the D/A converter 35 and the position data regarding the current position of the nozzle 6 from the external output device 10 are input to the gain switching circuit 37, and the gain that determines the response speed of the DC motor 17 is switched. This gain is set low when the nozzle 6 is on a straight line based on the coordinates of the work position stored during robot teaching, and high when the nozzle 6 is on a curved line.

The gain selected by the gain switching circuit 37 is summed with the feedback signal of opposite polarity generated by the tachometer generator 18 and inputted to the servo amplifier 36, and the output drives the DC motor 17. .

As a result, the detection device 4 rotates slowly around the central axis of the nozzle 6 when the application trajectory of the sealant 9 is a straight line, and rotates quickly when the application trajectory of the sealant 9 is a curved line. Regardless of the application trajectory of the sealer material 9, the distance between A and P is approximately constant as shown in FIG. The positions will be corrected so that they intersect.

In this embodiment, the DC motor 17 is controlled by the nozzle position data from the external output device 25.
Although the gain that determines the response speed is selected, the gain may be changed linearly depending on the degree of curvature of the application trajectory of the sealer material 9.

(Effect of the invention) As is clear from the above explanation, according to the invention, the application trajectory of the viscous fluid material is recognized based on the nozzle position data from the external control device, and the application trajectory of the viscous fluid material is recognized in the straight and curved parts. Since the response speed of the drive device is changed, the stability of tracking control for straight portions and the responsiveness of tracking control for curved portions are both improved, and the detection device can be used regardless of the application trajectory of the viscous fluid material. This makes it possible to always maintain the optimal tracking position.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a viscous fluid material application detection device according to the present invention, FIG. 2 is a block diagram of a signal processing circuit of the viscous fluid material application detection device according to the present invention, and FIG. 3 is an illustration. - D. Waveform diagrams of various parts to explain the operation of the signal processing circuit shown in FIG. 2, FIGS. 4 and 5. 1 is a perspective view schematically showing a viscous fluid material application detection device that is in the development stage. 1... Arm of robot (mobile device), 2...
Holder, 3... Application gun, 4... Detection device, 5...
...Fixed shaft, 6... Nozzle, 7... Hose, 8...
Panel (material to be coated), 9...Sealer material (viscous fluid material), 10...Control panel (control means), 11...Ball bearing, 12...Case, 13...Photographing lens, 14...Illumination lamp , 15... line sensor, 16... circuit board, 17... DC motor (drive device), 18... tachometer generator, 21...
... Connector, 22, 23, 24, 26 ... Cord, 25 ... External control device.

Claims (1)

[Scope of utility model registration request] A coating gun that applies a viscous fluid material such as a sealer to a moving device that moves along a predetermined work trajectory to a workpiece based on a signal from an external control device, and a viscous fluid produced by the coating gun. A viscous fluid material application detection device is equipped with a detection device that images and detects the application state of the material, and the detection device is attached to the coating gun so as to be rotatable around the center axis of its nozzle, and A viscous flow characterized in that a drive device is provided that rotates the detection device according to the coating posture of the coating gun, and a control means that changes the response speed of the drive device according to the work trajectory is connected to the drive device. Material application detection device.