JPH05224750A - Lifter height position control method for automatic carrying vehicle - Google Patents

Abstract

PURPOSE:To easily change the position of a lifter without changing the set position of a mark plate when a process is changed. CONSTITUTION:An automatic carrying vehicle 3 containing a lifter 6 for a work W is driven on a route including plural working sections. The lifter 6 is moved up and down when the vehicle 3 moves to an adjacent section and also controlled at the height set in each working section. Under such conditions, the distance L of the vehicle 3 traveled from a start position A is measured. Then the up-down movement of the lifter 6 is started when the distance L reaches the prescribed value set on the basis of the position A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an ascending / descending position of a lifter on which a work is placed in an automated guided vehicle traveling at a low speed along a traveling path.

[0002]

2. Description of the Related Art Conventionally, for example, when assembling an automobile, welding or the like, a conveyor has been used for conveying works (articles) continuously or intermittently in a certain direction. In recent years, an automated guided vehicle (AGV) has been adopted as an alternative to this. The automatic guided vehicle is a vehicle that has an automatic steering function and automatically conveys the work.

In the method using the unmanned guided vehicle, the unmanned guided vehicle travels at a low speed along a traveling path provided in line with the work line. The road is divided into multiple sections,
Workers are waiting in each section. Then, when the unmanned guided vehicle on which the work is placed reaches a predetermined section, the worker waiting in that section walks in accordance with the traveling speed of the unmanned guided vehicle while assembling the predetermined parts to the work. There is. According to this method, even in the same work line, since the assembly position of parts is different for each section or the height of the worker is different, the lifter on which the work is placed is changed every section. Is moved up and down to adjust the work to the optimum height.

In order to adjust the lift position of the lifter, conventionally, as shown in FIG. 6, mark plates 31 are installed at regular intervals d along the work line, and the automatic guided vehicle 3 is installed.
When the proximity sensor 33 on the lower surface of 2 detects the mark plate 31, the lifter 34 is moved up and down.

[0005]

In the method using the automatic guided vehicle 32, when the process is changed in the work line, the work position and work time of the worker are changed. This process change is required to be completed in a short time.

However, in the method of raising and lowering the lifter 34 at the same time as the detection of the mark plate 31 described above, it is necessary to change the installation position of the mark plate 31 when changing the process, and the process cannot be changed easily in a short time. Therefore, if the installation position of the mark plate 31 is to be changed without lowering the work efficiency, the process must be changed on a holiday when the work line is stopped.

The present invention has been made to solve the above problems, and an object thereof is to easily change the lift position of the lifter when changing the process without changing the installation position of the mark plate. An object of the present invention is to provide a method for controlling the lifted position of a lifter in an automated guided vehicle.

[0008]

In order to achieve the above object, the present invention allows an automated guided vehicle provided with a lifter for raising and lowering a workpiece to travel along a traveling path consisting of a plurality of sections.
A method for controlling the lift position of a lifter in an automated guided vehicle, wherein the lifter is moved up and down when the automated guided vehicle is moved to an adjacent section, and the lifter is set to a lifter height set for each section. Directly or indirectly measuring the traveling distance from a predetermined position of the traveling path, when the automatic guided vehicle travels a preset distance with reference to the predetermined position,
The lifting and lowering of the lifter is started.

[0009]

[Function] The automatic guided vehicle equipped with the lifter for lifting the work is
The vehicle travels along a traveling path composed of a plurality of sections. This automatic guided vehicle raises and lowers the lifter at the time of transition to an adjacent section so that the lifter has a lifter height set for each section. That is, when the automatic guided vehicle is traveling, the traveling distance from a predetermined position on the traveling path is directly or indirectly measured. Then, when the measured traveling distance of the automated guided vehicle reaches a distance set with the predetermined position as a reference, the lifter is started to move up and down.

Therefore, even if the interval of the section is changed when the process is changed in the work line or the like and the lifter lifting position needs to be changed, it is only necessary to reset the lifter lifting start distance from the predetermined position. No need to change the installation position of the mark plate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will now be described with reference to FIGS.
It will be described with reference to FIG. FIG. 1 is a diagram showing a part of an assembly work line in an automobile assembly factory or the like. On the floor surface 1 in this factory, there is a running guide wire 28 through which a guide signal flows.
Are laid, and the travel guide line 28 sets a travel path of the automatic guided vehicle 3. Also, on the floor 1,
A first guide wire 2 extending along the assembly work line is laid. FIG. 1 shows an example in which the first guide wire 2 extends in the left-right direction. Here, the right end portion of the first guide wire 2 constitutes the traveling start position A of the automatic guided vehicle 3. At the traveling start position A, the second guide wire 4 is laid, and a plurality of (a pair in this embodiment) mark plates 5 are installed in a state of being separated from each other.

Immediately before the traveling start position A (right side of FIG. 1)
At this point, a large number of unmanned guided vehicles 3 on which works W such as automobile bodies are placed are waiting (not shown in FIG. 1), and the leading unmanned guided vehicle 3 advances to the travel start position A. Then, when the automatic guided vehicle 3 starts at predetermined intervals, the next automatic guided vehicle 3 advances to the traveling start position A. In this way, the automatic guided vehicle 3 is sequentially operated at predetermined time intervals.
Is set to start. In this embodiment, the starting interval (time) of the automatic guided vehicle 3 is set as the starting tact T. The unmanned guided vehicle 3 that has started moves along the traveling path by detecting the traveling guide wire 28 with a pair of left and right traveling pickup coils (not shown) mounted on the bottom surface thereof.

The assembling work line is divided into a plurality of work sections having the same length, and a worker stands by in each work section. The assembly work performed by the worker is different for each work section. And the automated guided vehicle 3
As the vehicle travels, the assembly position of parts within each work section,
The lifter 6 of the automated guided vehicle 3 moves up and down according to the height of the worker, and the work W is adjusted to have an optimum height (lifter height H). The lifting operation of the lifter 6 is performed at a predetermined interval (elevating interval D). In each work section, the worker performs predetermined assembly work while walking according to the traveling speed of the automatic guided vehicle 3.

The first and second guide lines 2 and 4 and the traveling guide line 28 are connected to a control panel 7 installed at a place different from the traveling path. The control panel 7 includes an induction wireless oscillator 8
The start command oscillator 9 and the traveling guidance oscillator 29 are built in, the first induction wire 2 is connected to the induction wireless oscillator 8, the second guidance wire 4 is connected to the start instruction oscillator 9, and the traveling guidance is generated. The drive guide wire 28 is connected to the oscillator 29. The induction wireless oscillator 8 outputs two kinds of signals having different frequencies, and by combining these signals, various information is sent to the automatic guided vehicle 3 traveling in each section through the first guide wire 2. I try to send it. Further, the start command oscillator 9 outputs a start command signal via the second guide wire 4 every predetermined time. Further, the traveling guidance oscillator 29 outputs a guidance signal for performing steering control of the automatic guided vehicle 3 through the traveling guide wire 28.

On the front surface of the control panel 7, a start tact setting switch 11 for setting the start tact T of the automatic guided vehicle 3 is set.
And a lift interval setting switch 12 for setting a lift interval D of the lifter 6 and a lifter height setting switch 13 for setting a lifter height H, respectively.
As shown in FIG. 2, the various setting switches 11 to 13
Are electrically connected to the input side of the operation controller 14. The first guide wire 2 is electrically connected to the output side of the operation controller 14 via the induction radio oscillator 8, and the second guide wire 4 is electrically connected to the output side of the start command oscillator 9. ing. Furthermore, the operation controller 1
A traveling guide wire 28 is electrically connected to the output side of 4 through a traveling guide oscillator 29. Then, the operation controller 14 controls both oscillators 8 and 9 based on signals from the various setting switches 11 to 13.

At this time, the operation controller 14 uses the ascending / descending interval D set by the ascending / descending interval setting switch 12 and the starting tact T set by the starting tact setting switch 11, and based on the following equation (1), unmanned conveyance The command traveling speed V of the car 3 is obtained.

V = D / T (1) Next, the structure of the automatic guided vehicle 3 will be described. As shown in FIG. 1, a carrier body 15 that constitutes the lower part of each automated guided vehicle 3 is equipped with a plurality of wheels 16, some of which are drive wheels that are rotationally driven by a traveling motor 17. .. A pulse encoder 18 is attached to the traveling motor 17. The pulse encoder 18 outputs a pulse signal according to the rotation of the output shaft of the traveling motor 17. Therefore, by counting the number of pulse signals output from the pulse encoder 18, the traveling distance L of the automated guided vehicle 3 can be obtained.

The lifter 6 of each automated guided vehicle 3 is provided with a table 19 on which the work W is placed, and a connecting bar 21 which obliquely connects the table 19 and the guided vehicle main body 15. Two connecting bars 21 form one set, and a plurality of sets (only one set is shown in FIG. 1) are provided. Both connecting bars of each set 2
1 are rotatably connected to each other at a central portion in the length direction. The connecting bar 21 is operated by an elevating actuator 22, and the connecting bar 21 is expanded and contracted by changing the inclination angle of the connecting bar 21 to adjust the height of the work W. A stroke sensor 23 for detecting the vertical position of the table 19 is disposed near the connecting bar 21.

At the bottom of each automated guided vehicle 3, a plurality of proximity sensors 24 are provided for detecting the mark plate 5 at the traveling start position A. In addition, each automated guided vehicle 3
Has a built-in induction radio receiver 25 for receiving a signal from the induction radio oscillator 8 based on the magnetic field around the first induction wire 2. Similarly, each automatic guided vehicle 3 has a built-in start command receiver 26 for receiving a signal from the start command oscillator 9 based on the magnetic field around the second guide wire 4.

As shown in FIG. 3, the pulse encoder 18, the stroke sensor 23, the proximity sensor 24, the inductive radio receiver 25, and the start command receiver 26 are electrically connected to the input side of the vehicle controller 27. Also,
The traveling motor 17 and the lifting actuator 22 are electrically connected to the output side of the in-vehicle controller 27.
The in-vehicle controller 27 is the pulse encoder 1
8, the travel sensor 17 based on signals from the stroke sensor 23, the proximity sensor 24, and both receivers 25 and 26.
Also, the lifting actuator 22 is controlled.

Next, the operation and effect of this embodiment constructed as described above will be described. The flowchart of FIG. 4 shows a routine executed by the operation controller 14, and the flowchart of FIG. 5 shows a routine executed by the vehicle controller 27.

The operation controller 14 is step 1 in FIG.
In 01, the start tact T of the automatic guided vehicle 3 set by the start tact setting switch 11 and the lift interval D of the lifter 6 set by the lift interval setting switch 12
And the lifter height H set by the lifter height setting switch 13 are read. Next, the operation controller 14 outputs a drive signal to the start command oscillator 9 in step 102 and causes the start command oscillator 9 to oscillate the start command signal for each start tact T read in step 101.

Subsequently, the operation controller 14 proceeds to step 103, and uses the ascending / descending interval D and the starting tact T to obtain the command traveling speed V of the automated guided vehicle 3 based on the equation (1). That is, the ascending / descending interval D is divided by the starting tact T to obtain the command traveling speed V. Then, the operation controller 14 outputs a drive signal to the induction wireless oscillator 8 in step 104, and oscillates a data signal regarding the ascending / descending interval D, the command traveling speed V, and the lifter height H from the induction wireless oscillator 8, and this routine ends. To do.

Next, a routine by the vehicle controller 27 of FIG. 5 will be described. The in-vehicle controller 27 first reads the detection signal from the proximity sensor 24 in step 201. This reading is performed when the automatic guided vehicle 3 is on standby immediately before the traveling start position A. The in-vehicle controller 27 determines in step 202 whether or not the automated guided vehicle 3 has reached the traveling start position A. When the proximity sensor 24 and the mark plate 5 face each other, the in-vehicle controller 27 outputs a signal for stopping the driving of the traveling motor 17 in step 203 due to a change in the signal from the proximity sensor 24. Then, the automated guided vehicle 3 temporarily stops at the traveling start position A.

The in-vehicle controller 27 executes step 204
At, the data signal relating to the ascending / descending interval D, the commanded traveling speed V, and the lifter height H oscillated from the induction wireless oscillator 8 is read via the first induction wire 2 and the induction wireless receiver 25. In addition, the in-vehicle controller 27 performs step 20.
5, the start command signal oscillated from the start command oscillator 9 is supplied to the second guide wire 4 and the start command receiver 26.
Read through. When the start command signal and the data signal relating to the lifter height H are read, the in-vehicle controller 27 outputs drive signals to the stopped traveling motor 17 and lifting actuator 22 in step 206. Then, the automatic guided vehicle 3 starts with the operation of the traveling motor 17, and starts traveling at the instructed traveling speed V along the first guide line 2. Further, the lifter 6 moves up and down in accordance with the operation of the lifting actuator 22, and the height of the work W becomes the set lifter height H.

Therefore, the worker standing by in the first work section walks in accordance with the traveling speed of the unmanned transporter 3 and performs a predetermined assembling work on the work W held at the optimum height. It is possible.

When the automatic guided vehicle 3 starts traveling, the in-vehicle controller 27 determines in step 207 the pulse encoder 1
The pulse signals output from 8 are counted, and the number of revolutions of the traveling motor 17, that is, the traveling distance L of the automated guided vehicle 3 is calculated from the number. Subsequently, the in-vehicle controller 27 determines in step 208 whether or not the traveling distance L is an integral multiple of the ascending / descending distance D, and if it is not an integral multiple, step 209.
Then, in order to maintain the lifter height H up to that point, a signal for stopping the operation of the lifting actuator 22 is output. Then, when the calculated traveling distance L becomes an integral multiple of the ascending / descending distance D, the vehicle controller 27 determines that it is time to transition from the current work section to the next work section, and step 21
At 0, a drive signal is output to the lifting actuator 22.
Then, the lifting actuator 22 operates, and the lifter 6
The ascending and descending of is started.

The in-vehicle controller 27 executes step 211.
Then, the lifter height at that time is read by the stroke sensor 23, and then the routine proceeds to step 212, where it is determined whether or not the read lifter height is equal to the commanded lifter height H. When the lifter 6 moves up and down as the lifting actuator 22 is driven, and the actual lifter height reaches the commanded lifter height H, the in-vehicle controller 27 causes the in-vehicle controller 27 to perform step 2.
At 13, a signal for stopping the operation of the lifting actuator 22 is output. When the lifting operation of the lifter 6 is stopped,
The in-vehicle controller 27 repeats the processing after step 204. Therefore, the lifter 6 is moved up and down for each work section, and the work W reaches the commanded lifter height H.

As described above, in this embodiment, the automatic guided vehicle 3 provided with the lifter 6 for raising and lowering the work is caused to travel along the travel path composed of a plurality of work sections. When the automatic guided vehicle 3 moves to an adjacent section, the lifter 6 is moved up and down to the lifter height H set for each work section. Specifically, when the automated guided vehicle 3 is traveling, the traveling distance L from a predetermined position (travel starting position A) on the traveling path is directly measured (step 207). Then, when the measured traveling distance L of the automated guided vehicle 3 becomes a distance set in advance with the traveling start position A as a reference, the lifting and lowering of the lifter 6 is started (steps 208, 21).
0).

Therefore, even if the interval of the work section is changed and the lift position of the lifter 6 needs to be changed when the process is changed in the assembly work line or the like, the lift interval setting switch 12 is operated to move the lift interval of the lifter 6. All you have to do is reset D. Therefore, it is not necessary to perform a troublesome change work such as the conventional installation position of the mark plate 31.

Further, the change of the ascending / descending interval D can be set on the control panel 7 side in a short time by using induction radio. For this reason,
Unlike the conventional technique in which the process has to be changed on a holiday when the work line is stopped, the process can be changed even on the working day of the work line in this embodiment.

Further, in this embodiment, when the traveling distance L of the automatic guided vehicle 3 from the traveling start position A becomes an integral multiple of the commanded elevation interval D, the lifting and lowering of the lifter 6 is started. .. Therefore, under the condition that the traveling speed of the automatic guided vehicle 3 is constant and the lengths of the respective work sections are uniform as in the present embodiment, the automatic guided vehicles 3 to the adjacent work sections are guided to each other. The lifter 6 will always move up and down during the transfer. Therefore, the lifter 6 should be used except when the work section is moved to the adjacent work section
When the robot moves up and down, an unnecessary waiting time may occur and work efficiency may be reduced, but such a problem can be avoided in the present embodiment.

The present invention is not limited to the configuration of the above-mentioned embodiment, and may be arbitrarily modified within the scope not departing from the spirit of the invention, for example, as follows. (1) In the above-described embodiment, the ascending / descending interval D is set on the control panel 7 side, and the data signal thereof is guided by the in-vehicle controller 2
However, instead of this, the distance from the travel start position A when the lifter 6 is moved up and down is stored in the memory of the in-vehicle controller 27 in advance, and the travel distance L of the automated guided vehicle 3 is Lifter 6 when the memorized distance is reached
May be moved up and down. (2) In the above embodiment, the pulse signal from the pulse encoder 18 is counted to calculate the traveling distance L of the automatic guided vehicle 3. However, under the condition that the automatic guided vehicle 3 is traveling at a constant speed, traveling is performed. The traveling distance L may be indirectly obtained based on the elapsed time from the start. (3) In the above embodiment, the automatic guided vehicle 3 is temporarily stopped at the traveling start position A, but at the traveling start position A, the automatic guided vehicle 3 may be made to travel at a slow speed. (4) The present invention can be applied to a welding work line as well as an assembly work line.

[0034]

As described above in detail, according to the present invention, the traveling distance of the automatic guided vehicle from the predetermined position on the traveling path is directly or indirectly measured, and the preset distance based on the predetermined position is used as a reference. Since the lifter lift is started when the automatic guided vehicle travels, the lifter lift position can be easily changed without changing the mark plate installation position when changing the process. Play.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a lifter up-and-down position control method in an embodiment embodying the present invention.

FIG. 2 is a block diagram showing an electrical configuration of a control panel in one embodiment.

FIG. 3 is a block diagram showing an electrical configuration of an automated guided vehicle in one embodiment.

FIG. 4 is a flowchart showing a routine executed by the operation controller in the embodiment.

FIG. 5 is a flowchart showing a routine executed by the vehicle controller according to the embodiment.

FIG. 6 is a diagram illustrating a conventional lifter lift position control method.

[Explanation of symbols]

3 ... Automated guided vehicle, 6 ... Lifter, A ... Running start position, H ...
Lifter height, L ... Distance traveled, W ... Work

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[Procedure amendment]

[Submission date] May 10, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

The present invention is not limited to the configuration of the above-mentioned embodiment, and may be arbitrarily modified within the scope not departing from the spirit of the invention, for example, as follows. (1) In the above-described embodiment, the ascending / descending interval D is set on the control panel 7 side, and the data signal thereof is guided by the in-vehicle controller 2
The output of the lifter 6 is made instead of the above.
The distance from the travel start position A when moving up and down is stored in the memory of the vehicle controller 27 in advance, and the lifter 6 is moved up and down when the running distance L of the automatic guided vehicle 3 reaches the stored distance. Good. (2) In the above embodiment, the pulse signal from the pulse encoder 18 is counted to calculate the traveling distance L of the automatic guided vehicle 3. However, under the condition that the automatic guided vehicle 3 is traveling at a constant speed, the traveling is performed. The traveling distance L may be indirectly obtained based on the elapsed time from the start. (3) In the above-described embodiment, the automatic guided vehicle 3 is temporarily stopped at the traveling start position A, but at the traveling start position A, the automatic guided vehicle 3 may be driven at a slow speed. (4) The present invention can be applied to various places such as a welding work line, an adjustment work line, and a test work line, in addition to the assembly work line.

Claims (1)

[Claims] 1. An unmanned guided vehicle provided with a lifter for raising and lowering a work is run along a traveling path composed of a plurality of sections, and when the unmanned guided vehicle is moved to an adjacent section, the lifter is raised and lowered. A lifter elevation control method for an automated guided vehicle, wherein the lifter is set to a lifter height set for each section, which directly or indirectly measures a travel distance from a predetermined position of the travel path, A lifter up-and-down position control method for an automatic guided vehicle, wherein when the automatic guided vehicle travels a preset distance with reference to the predetermined position, the lifter is moved up and down.