JPH0411266B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention automatically rotates a coating machine by a certain angle in response to a preprogrammed change in the shape of an object to be coated so that it faces the surface to be coated. This invention relates to a tilt angle control mechanism for automatic painting equipment.

[Conventional technology]

An automobile painting line is equipped with a top machine that automatically and continuously paints the front, top, and rear surfaces of automobile bodies that are conveyed at a constant speed by a conveyor.

This top machine has a coating machine attached to an elevating frame that is horizontally arranged perpendicular to the conveyance path of the car body. The coating machine is rotated in a direction parallel to the conveyance path and tilted by a certain angle, so that the coating machine is always directly facing the painted surface of the automobile body.

In order to control this tilt angle, conventionally, a mechanism has been adopted in which the current value of the tilt angle is detected by counting signals from a rotary transducer using an alternating binary code.

[Problem that the invention seeks to solve]

However, when painting the front, top, and rear surfaces of an automobile body continuously, the paint sprayer, which is in a vertical position, must first be tilted 90 degrees to the rear to paint the front surface, and then returned to the vertical position. The tilt angle of the paint sprayer is the total of
It becomes 180°. Therefore, within this range, for example, 1°
If we wanted to control the signal in increments with high precision, eight types of code patterns would be required, and the signal detection system that detects signals from the code patterns would also become complicated.
The entire rotary transducer has become large and very expensive.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive and compact tilt angle control mechanism that can control the tilt angle of a paint sprayer using an extremely simple code pattern.

[Means for solving problems]

In order to achieve this objective, the present invention provides a tilt angle for an automatic coating device that automatically rotates the coating machine by a certain angle in response to a preprogrammed change in the shape of the object to be coated to directly face the coating surface. In the control mechanism, a rotary encoder measures the rotation direction and rotation angle of the paint sprayer by converting it into a pulse signal using a pulse scale that rotates in response to the rotation;
A control device is provided that outputs a control signal for adjusting the tilt angle of the paint sprayer based on the measured value of the rotary encoder, and the rotary encoder is arranged in parallel along the direction of rotation of the rotary encoder, facing the code pattern of the pulse scale. It consists of a pair of optical signal detection systems installed, and a reversible counter that detects the current value of the tilt angle by counting two-phase pulse signals having a constant phase difference output from each optical signal detection system, The control device determines the tilt direction of the sprayer by comparing the current value of the tilt angle detected by the reversible counter with a preprogrammed tilt angle setting value according to a change in the shape of the object to be coated. , is characterized in that it is configured to output a control signal to rotate the paint sprayer by a certain angle in the tilt direction.

[Effect]

According to the present invention, when the pulse scale rotates in either the forward or reverse direction in response to the rotation of the paint sprayer,
Two-phase pulse signals having a certain phase difference are output from a pair of optical signal detection systems arranged in parallel facing the code pattern along the rotation direction of the pulse scale, and two-phase pulses having this phase difference are output. The signal is counted by a reversible counter to detect the current value of the sprayer's tilt angle.

That is, for example, when the paint sprayer rotates forward and the pulse scale rotates forward, the optical signal detection system outputs a two-phase pulse signal with a phase difference of +90°; When the pulse scale is reversed, two-phase pulse signals having a phase difference of -90° are output.

Next, the reversible counter determines the tilt angle of the paint sprayer based on the rotation direction determined by the output order of the pulse signals having this phase difference and the rotation angle determined by counting one of the pulse signals. Find the current value of.

Then, the control device compares the current value of the tilt angle detected by this reversible counter with a pre-programmed tilt angle setting value that corresponds to changes in the shape of the object to be coated, and determines the tilt direction of the sprayer. The control device outputs a control signal to rotate the coating machine by a certain angle, so that the coating machine is always directly facing the painting surface of the object to be coated.

Therefore, the tilt angle can be precisely controlled by simply forming one type of code pattern on the pulse scale, and the entire elevation control mechanism can be significantly simplified and miniaturized and manufactured at low cost.

〔Example〕

Hereinafter, the present invention will be specifically described based on embodiments shown in the drawings.

Fig. 1 is a flow sheet showing the tilt angle control mechanism of an automatic painting apparatus according to the present invention, Fig. 2 is a front view showing an enlarged part of the mechanism, Fig. 3 is an enlarged view of the pulse scale, and Figs. b A waveform diagram of pulse signals output from a pair of optical signal detection systems, FIG. 5 is a flowchart showing the processing procedure of the control device, and FIG. 6 is an explanatory diagram showing the tilting operation of the coating machine.

In the figure, T is a top machine in which a coating machine 4 is attached to an elevating frame 3 horizontally disposed perpendicular to a conveyance path through which an automobile body 1 to be painted is conveyed at a constant speed by a conveyor 2.

The lifting frame 3 has both ends connected to the automobile body 1.
Bearings 6 fixed at the lower ends of a pair of links 5A and 5B that are movable in a pendulum direction perpendicular to the conveyance path of
It is supported by rotating shafts 7, 7 which are pivotally supported by the vehicle body 1, and is suspended horizontally so as to be rotatable back and forth along a direction parallel to the conveyance path of the automobile body 1.

The upper ends of the links 5A and 5B are rotatably mounted and supported in a direction perpendicular to the conveyance path of the automobile body 1 to brackets 9 and 9 of a lifting drive device 8 that raises and lowers the lifting frame 3.

Further, a tilting air motor 10 that is driven to rotate in forward and reverse directions is disposed on the upper end side of one link 5A, and supports a driving sprocket 11 fixed to the rotating shaft of the air motor 10 and the lifting frame 3. A driven sprocket 12 fixed to the rotating shaft 7
A drive chain 13 is hung in parallel between the coating machine 4 and the lifting frame 3 of the coating machine 4 so as to be rotated in the front-rear direction along the conveyance path of the automobile body 1.

In addition, the other link 5B has an elevating frame 3.
A connecting rod 14 of an oscillating device (not shown) for making a pendulum movement is rotatably connected.

Next, 15 is a rotary encoder that measures the rotation direction and rotation angle of the sprayer 4, and is fixed to the rotation shaft 7 of the lifting frame 3 to which the sprayer 4 is attached, for example, and is configured to respond to the rotation of the sprayer 4. A pulse scale 16 that is rotated in forward and reverse directions, a pair of optical signal detection systems 17A and 17B that are arranged in parallel along the rotation direction facing the code pattern P of the pulse scale 16; Signal detection system 17
A reversible counter 18 detects the current value of the tilt angle of the coating machine 4 by counting two-phase pulse signals having a phase difference of 90° outputted from A and 17B.

Note that since the maximum tilt angle of the coating machine 4 is 180°, the code pattern P is formed in a semicircular shape in the upper half of the disc-shaped pulse scale 16.

Further, an arcuate slit 19 having a light shielding part 19a in the middle is formed in the lower half of the pulse scale 16, and faces the light shielding part 19a, so that the reversible counter 18 can be opened when the sprayer 4 is in the vertical state. An optical signal detection system 17C that outputs a detection signal for performing zero point correction is provided.

In addition, each optical signal detection system 17A, 17B and 17
C denotes an optical fiber 20 of a predetermined length into which an optical signal is input, and an optical sensor 21 that converts the optical signal transmitted through the optical fiber into an electrical signal and outputs it.
and an amplifier 22 that amplifies the signal output from the optical sensor 21.

Next, 23 is a control device that outputs a control signal for adjusting the tilt angle of the paint sprayer 4 based on the measured value of the rotary encoder 15, and is a control device that outputs a control signal for adjusting the tilt angle of the paint sprayer 4 based on the measured value of the rotary encoder 15, and is a control device that outputs a control signal for adjusting the tilt angle of the paint sprayer 4 based on the measured value of the rotary encoder 15. The tilt direction of the paint sprayer 4 is determined by comparing this value with a pre-programmed tilt angle setting value that corresponds to changes in the shape of the automobile body 1, and the paint sprayer 4 is moved at a certain angle in the tilted direction. A control signal for rotation is output to an electro-pneumatic converter 24 that controls the rotation of the air motor 10.

That is, on the input side of the control device 23, there is a reversible counter 18 that detects the current value of the tilt angle of the paint sprayer 4.
is connected to an integration counter 25 that detects the current position of the automobile body 1 being conveyed by the conveyor 2, while an electro-pneumatic converter 24 that controls the rotation direction and rotation angle of the air motor 10 is connected to its output side. has been done.

Note that the integration counter 25 includes a pulse generator 26 that outputs a pulse signal in synchronization with the conveyance speed of the conveyor 2, and a phototube switch or proximity sensor that detects the arrival of the automobile body 1 and outputs a detection signal. When the detection sensor 27 is connected and the integration counter 25 is reset by the detection signal output from the position detection sensor 27, the integration counter 25 starts counting the pulse signal output from the pulse generator 26. car body 1
The value of the current position can now be found.

Therefore, due to the rotation of the pulse scale 16,
Two-phase pulse signals CA and CB having a phase difference of, for example, 90° are output from the optical signal detection systems 17A and 17B.

For example, when the pulse scale 16 rotates in the direction of arrow _F1 shown in FIG. 3, the pulse signals CA and CB become (CA _OFF , CB _OFF ) as shown in FIG. 4 a.
→(CA _ON , CB _OFF )→(CA _ON , CB _ON )→
(CA _OFF , CB _ON ) is output in the order of arrow F ₂
When rotated in the direction, as shown in Figure 4b,
(CA _OFF , CB _OFF ) → (CA _OFF , CB _ON ) →
Output is in the order of (CA _ON , CB _ON ) → (CA _ON , CB _OFF ).

Therefore, by determining the output order of the pulse signals CA and CB using the reversible counter 18, the rotational direction of the pulse scale 16 can be determined, and thereby the rotational direction of the atomizer 4 can be determined. Further, by counting the number of pulses of either one, the rotation angle of the sprayer 4 is determined, and the current value of the tilt angle of the sprayer 4 is detected based on this rotation angle and the rotation direction.

Note that the reversible counter 18 receives, for example, a pulse signal.
By determining whether the pulse signal CA changes from off to on or from on to off when CB is on, the former is counted as +1 pulse, and the latter is counted as -1 pulse. , detects the current value of the coating machine 4.

Then, the current value of the tilt angle of the paint sprayer 4 detected by the reversible counter 18 in this way and the value of the current position of the automobile body 1 detected by the integration counter 25 are input to the control device 23, and the control device 23 Executes predetermined arithmetic processing.

FIG. 5 shows the processing procedure. First, in step, the value of the current position of the car body 1 inputted from the integration counter 25 is temporarily stored, and then in the step, the value of the current position of the car body 1, such as the front end, center, or rear end, is stored. The set value of the tilt angle of the sprayer 4, which has been programmed in advance according to the shape that changes depending on the position, is read out from a predetermined storage area, and the process moves to step.

In the step, the current value of the tilt angle of the paint sprayer 4 inputted from the reversible counter 18 is temporarily stored, and the process moves to the step.

Next, in step, the set value of the sprayer 4 read out in step is compared with the current value temporarily stored in step to determine whether the two values match. Return to step 1, and if they do not match, proceed to step and calculate the difference value.

If the current value is smaller than the set value, that is, if the tilt angle of the sprayer 4 is too small, the process moves to step and outputs a control signal to the electropneumatic converter 24 to drive the air motor 10, for example, in the forward rotation. Then, the coating machine 4 is rotated in a direction to increase its tilt angle.

Next, the process moves to step and again determines whether or not the set value and the current value match. If they match, the process moves to step and outputs a stop signal to the electro-pneumatic converter 24 to stop driving the air motor 10. and return to step.

On the other hand, in step, if the current value is larger than the set value, that is, if the tilt angle of the sprayer 4 is too large, the process moves to step and a control signal is sent to the electro-pneumatic converter 24 to drive the air motor 10 in reverse. output, and rotates the coating machine 4 in a direction that reduces its tilt angle.

Next, the process moves to step and determines whether or not the set value and the current value match. If they match, the process moves to step and outputs a stop signal to the electro-pneumatic converter 24 to stop driving the air motor 10. and return to the step.

Therefore, when the coating machine 4 is in a vertical position directly facing the horizontal upper surface of the automobile body 1 (tilt angle: 0°), as shown in FIG. Accordingly, adjust the tilt angle of the paint sprayer 4 to +90° for the front, +5° for the bonnet, +45° for the front pillar, 0° for the roof, -35° for the rear pillar, 0° for the trunk, and 0° for the rear. If the angle is programmed and set in the control device 23 in advance, such as -90°, the coating machine 4 will be continuously tilted at a predetermined angle in response to changes in the shape of the automobile body 1 being conveyed by the conveyor 2. The machine 4 is always maintained in a state directly facing the painted surface of the automobile body 1.

At this time, the current value of the tilt angle of the sprayer 4 is detected based on two-phase pulse signals with a 90° phase difference output from one type of code pattern P, so the pulse scale 16 and its light Signal detection system 1
7A and 17B are significantly simplified and miniaturized.

In addition, in the embodiment, the pulse scale 16
has been described with reference to the case where it is directly attached to the rotating shaft 7 of the elevating frame 3, but the present invention is not limited to this. Bye.

〔Effect of the invention〕

As described above, the tilt angle control mechanism according to the present invention includes a pulse scale that rotates as the paint sprayer rotates, and a pair of optical signal detection systems that detect two-phase pulse signals output by the rotation of the pulse scale. Then, the rotation direction of the paint sprayer is determined based on the output order of two pulse signals having a phase difference outputted from the optical signal detection system, and at the same time, the rotation angle of the paint sprayer is determined by counting the number of pulses of either one. With an extremely simple and compact mechanism consisting of a reversible counter that determines This has such excellent effects that the cost of the mechanism can be significantly reduced.

[Brief explanation of drawings]

Fig. 1 is a flow sheet showing the tilt angle control mechanism of an automatic painting apparatus according to the present invention, Fig. 2 is a front view showing an enlarged part of the mechanism, Fig. 3 is an enlarged view of the pulse scale, and Figs. 5 is a waveform diagram of pulse signals output from a pair of optical signal detection systems, FIG. 5 is a flow sheet showing the processing procedure of the control device, and FIG. 6 is an explanatory diagram showing the tilting operation of the coating machine. Explanation of symbols, 1... Automobile body (object to be painted),
3...Elevating frame, 4...Painting machine, 10...Air motor, 15...Rotary encoder, 16
...Pulse scale, P...Code pattern, 1
7A, 17B... Optical signal detection system, 18... Reversible counter, 23... Control device, 24... Electro-pneumatic converter.

Claims (1)

[Scope of Claims] 1. A tilt angle control mechanism of an automatic coating device that automatically rotates a coating machine by a certain angle in response to a preprogrammed change in the shape of an object to be coated to directly face a coating surface. A rotary encoder measures the rotational direction and angle of the sprayer by converting it into a pulse signal using a pulse scale that rotates in response to the rotation, and a control signal that adjusts the tilt angle of the sprayer based on the measured values of the rotary encoder. A control device for outputting is provided, and the rotary encoder includes a pair of optical signal detection systems arranged in parallel along the rotation direction of the code pattern of the pulse scale, and a control device for outputting signals from each of the optical signal detection systems. and a reversible counter that detects the current value of the tilt angle by counting two-phase pulse signals having a certain phase difference. It determines the tilt direction of the sprayer by comparing it with the programmed tilt angle setting value that corresponds to the shape change of the object to be painted, and outputs a control signal to rotate the sprayer by a certain angle in the tilt direction. A tilt angle control mechanism for an automatic painting device, characterized in that: 2. The tilt angle control mechanism according to claim 1, wherein the two-phase pulse signals have a phase difference of 90°. 3. The tilt angle control mechanism according to claim 1, wherein the coating machine is attached to an elevating frame disposed perpendicular to the conveyance path of the object to be coated and rotated integrally with the elevating frame. .