CA1323084C - Method of controlling operation of automated guided vehicle - Google Patents
Method of controlling operation of automated guided vehicleInfo
- Publication number
- CA1323084C CA1323084C CA000566476A CA566476A CA1323084C CA 1323084 C CA1323084 C CA 1323084C CA 000566476 A CA000566476 A CA 000566476A CA 566476 A CA566476 A CA 566476A CA 1323084 C CA1323084 C CA 1323084C
- Authority
- CA
- Canada
- Prior art keywords
- speed
- production line
- line
- production
- transportation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 claims abstract description 82
- 230000004044 response Effects 0.000 claims description 5
- 230000003247 decreasing effect Effects 0.000 claims description 2
- 238000004806 packaging method and process Methods 0.000 abstract description 8
- 230000005672 electromagnetic field Effects 0.000 description 7
- 230000001276 controlling effect Effects 0.000 description 5
- 238000009434 installation Methods 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 230000004075 alteration Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000008034 disappearance Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000000661 pacemaking effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D1/00—Control of position, course or altitude of land, water, air, or space vehicles, e.g. automatic pilot
- G05D1/02—Control of position or course in two dimensions
- G05D1/021—Control of position or course in two dimensions specially adapted to land vehicles
- G05D1/0259—Control of position or course in two dimensions specially adapted to land vehicles using magnetic or electromagnetic means
- G05D1/0265—Control of position or course in two dimensions specially adapted to land vehicles using magnetic or electromagnetic means using buried wires
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D1/00—Control of position, course or altitude of land, water, air, or space vehicles, e.g. automatic pilot
- G05D1/02—Control of position or course in two dimensions
- G05D1/021—Control of position or course in two dimensions specially adapted to land vehicles
- G05D1/0212—Control of position or course in two dimensions specially adapted to land vehicles with means for defining a desired trajectory
- G05D1/0223—Control of position or course in two dimensions specially adapted to land vehicles with means for defining a desired trajectory involving speed control of the vehicle
Abstract
ABSTRACT OF THE DISCLOSURE
A method of controlling the operation of an A.G.V. which automatically operates to go round along a predetermined route formed in a factory and travels along a plurality of production lines having different line contacts and adapted to perform parts assembly or packaging. Optimum travel speeds with respect to all the lines are previously stored in the A.G.V. When the A.G.V. enters one of the production lines, it is instructed from the outside to travel constantly at a speed assigned to this production line and previously stored. In this state, operations of the production line are successively performed.
A method of controlling the operation of an A.G.V. which automatically operates to go round along a predetermined route formed in a factory and travels along a plurality of production lines having different line contacts and adapted to perform parts assembly or packaging. Optimum travel speeds with respect to all the lines are previously stored in the A.G.V. When the A.G.V. enters one of the production lines, it is instructed from the outside to travel constantly at a speed assigned to this production line and previously stored. In this state, operations of the production line are successively performed.
Description
SPECIFICATION
TITLE OF THE INVENTION
NETHOD OF CONTROLLING OPERATION OF AUTOMATED GUIDED
VEHICLE
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a method of controlling the operation of an Automated Guided Vehicle (hereinafter abbreviated to A.G.V.) used as a means of transportation for production line work performed in a machine manufacturing works.
Description of Prior Art In general, production line work in a machine manufacturing works such as an automobile manufacturing works is usually performed with a conveyor system. In particular, with respect to a production line work mainly performed by way of manual operations, the relevant operations are usually performed by using a conveyor system. This is because a well-paced performance, based on the continuous flow of a conveyor, is regarded as important.
However, a production line applied to a conventional conveyor system involves a number of work stages, and the length of the production line is inevitably quite considerable. The size of the installation is thus correspondingly increased and it is difficult to provide paths for the movement of workers and the supply of parts. Such a system is also defective in terms of adaptability to changes in the overall layout of the works.
The introduction of A.G.V.s to parts assembly lines or parts packaging lines is currently being eagerly studied as an alternative to the use of conveyor systems.
~. .
.
~ 3~3084 Examples of techniques allowing such applications are disclosed in Japanese Patent Laid-Open No. 60-137476, "AUTOMATION" (published by Nikkan Kogyo Shinbun Shia in 1986, Vol. 31, No. 8, pp 36 - 42), and "MATERIAL HANDLING
ENGINEERING" ~published by PENTON-IPC in USA, 1985, pp 52 - 56).
In all the techniques for introduction of A.G.V.s disclosed in these documents, the speed at which an A.G.V.
travels is constant, an~ an operation of assembling or packaging parts is performed each time the vehicle stops at a station for a predetermined period of time.
Consequently, such a vehicle system cannot serve as a way of maintaining a desired pace and cannot constantly maintain a certain level of working hours and production line speed, thus resulting in a lowering of production efficiency.
In the system disclosed in Japanese Patent Laid-Open No. 60-137476, the time for the stop at each station is controlled in accordance with the time taken by each work stage in a production line. In this system, lamps may be provided at each station in order to inform workers of the passage of working time or the time remaining for the given task. However, this system cannot serve to maintain a certain pace commensurate with the performance of production line work since the pace keeping function of this system does not become second nature to a person, like the continuous flow of a conveyor system.
There is a possibility that it will result in operations becoming non-uniform. There is also a problem in that the administrator or supervisor is not informed of the progress of operation and whether it is ahead of or behind in time relative to a set standard.
SUMMARY OF THE INVENTION
A general technical concern of the present .~
`: . '' ' , , , ' ,.: ' ' ,''`' `' ' , ' ~ .
., ' .
,. : .. ' :
invention is the solution to certain problems relating to the introduction of A.G.V.s to an assembly or packaging line based on the above-described conventional techniques, and an object of the present invention is to provide an improved method of controlling the operation of an A.G.V., a method of providing a pace keeping function similar to that of a conveyor system while utilizing the benefits of introducing A.G.V.s, and a method which also serves to positively improve the production ef f iciency, thereby making a substantial contribution to the field of production line transportation techniques.
Thus, the present invention provides a method of controlling the operation of an A.G.V. to carry workpieces along production lines to a plurality of successive work stations at a speed corresponding to a predetermined distinctive workpiece conveyor speed for the respective production line in a manufacturing area of a plant, comprising the steps of defining a boundary of the manufacturing area with a transportation line having a workload entrance station and a workload exit station:
providing a plurality of parallel spaced production lines;
within the defined boundary; providing a plurality of successively disposed work stations along each production line; connecting the transportation line and each production line by a guide wire provided in the manufacturing area floor; propelling the ~.G.V. at a transportation line speed by detecting a magnetic field generated continuously from the transportation line to each of the production lines and from each production line to the transportation line; generating a speed command signal adjacent the entrance and exit ends of each production line for controlling the A.G.V. entering and exiting a respective production line; storing on the A.G.V. speed data corresponding to a predetermined distinct workpiece conveyor speed for each production .:
: . .
~ - ~
. . .
line; each distinct workpiece conveyor speed being continuous and each being less than the transportation line speed through the work stations of each production line: each distinct workpiece conveyor speed being the desired speed for performing manufacturing operations at the work stations along each corresponding production line; detecting on the A.G.V. the generated speed command signals of the corresponding entrance and exit end of the respective production line; decreasing the speed of the ~.G.V. from the transportation line speed to the respectivQ stored speed for the corresponding production line until the speed of the A.G.V. is equal to the distinct workpiece conveyor speed in response to the generated speed command signal at the entrance end of a respective production line; propelling the A.G.V. at the corresponding stored distinct workpiece conveyor speed ~
along the production line continuously; and increasing the ;' speed of the A.G.V. to the speed of the transportation line speed in response to the generated speed command signal at the exit end of the corresponding production line.
The present invention enables a pace keeping function similar to that of a conveyor system while utilizing the benefits of introducing A.G.V., such as increase in the degree of freedom in relation to changes in the layout in the factory and improvement in space utilization efficiency, thereby positively improving the production efficiency of the production line wor~.
A system in accordance with the present invention is preferably designed such that a speed control device is mounted on the A.G.V. Optimum travel speeds with respect to all of the production lines having different line contacts are stored in the speed control device, and a speed change command is supplied from the outside to the speed control device so as to change the speed of the , A.G.V. to a set speed assigned to one of the production lines when the A.G.V. enters this line. This eliminates the need for the provision of a large installation such as a conveyor system and ensures that the system in S accordance with the present invention can be adapted to changes in the layout in the factory by simply changing the operation route of the A.G.V. Since the A.G.V. can always continuously travel at a constant and low speed in a production line, it effects a positive pace making performance equivalent to that of a conveyor system during the production line process.
The method of mounting the speed control device of the A.G.V., storing optimum travel speeds in the speed control device, and assigning to the A.G.V. the speed corresponding to a production line in which the vehicle travels, enables a type of A.G.V. to be used in a plurality of production lines, thereby increasing the degree of freedom relative to different types of production line as well as mass production of A.G.V.s and, hence, a reduction in installation costs.
The invention will hereinafter be described by way of example only and with reference to the accompanying drawings.
~RIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate an embodiment of the present invention;
Fig. 1 is a schematic plan view of a part of the layout of production lines in a factory;
Fig. 2 is a schematic plan view of the whole of the layout shown in Fig. l;
Fig. 3 is a schematic side view of an A.G.V.;
Fig. 4 is an operational flow chart of the A.G.V.;
and Fig. 5 graphically illustrates the speeds of the ,...
": .
,. . . , , . .. :. :
.
.
.
` 1 323084 unmanned cart at different production lines.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figs. 1 to 3, production lines 1 (1', 1", 1"') for parts assembly and packaging are provided in a factory.
Desired parts to be assembled or packed and devices used for desired operations are disposed along the production line 1 (1', 1", 1"l).
A workload entrance station 3 and a workload exit station 4 are disposed in desired positions on a floor 2.
A travel guide wire 5 is embedded in the floor 2 in such a manner that it forms a loop which connects the workload entrance station 3, the workload exit station 4, and the 15 production lines 1 (1', 1", 1"l). The travel guide wire 5 is connected to an oscillation amplifier (not shown) and is supplied with a low-frequency current of a desired frequency so that generates electromagnetic field around its ou~er circumference.
As shown in Fig. 1, speed command transmitting ~tations No and No~ are disposed at the upstream and downstream ends of the production line 1 (1', 1", 1"').
The region between the speed command transmitting stations No and Nol is sectioned into work stations Nl, N2, N3, N4 and N5. An optical command oscillator 6 is provided at each of the speed command transmitting stations No and Nol. A start-stop command guide wire 7 is embedded at each of the work stations Nl, N2, N3, N4 and N5 in such a manner that it extends across the travel guide wire 5 in the work line 1 (1', 1", 1"'). The start-stop command wire 7 is connected to an oscillator (not shown~ via a hold switch 8 and is supplied with a low-frequency current of a desired frequency different from that of the current supplied to the travel guide wire 5 so that it generates an electromagnetic field around its outer periphery.
... .
... . .:
An A.G.V. 9 has a drive motor ~not shown) (such as one connected to a rotary encoder of a high resolution type for velocity feedback and to a controller) capable of being speed-controlled with accuracy, and a microcomputer (not shown) provided as a speed controller. The rotation of the motor is controlled on the basis of information issued from the microcomputer so that it is regulated to a set speed.
A pair of left and right pickup coils 10 responsive to the electromagnetic field produced by the travel guide wire 5 and a pickup coil 11 responsive to the electromagnetic field produced by each start-stop command guide wire 7 are disposed on an outside surface of the A.G.V. 9. The pickup coils 10 are electrically connected to a steering device (not shown), and steering is performed on the basis of the difference between electromokive forces induced in the left and right pickup coils 10. The pickup coil 11 is electrically connected to a power switch of the drive motor, and the power supply to the drive motor is switched on or off in response to the occurrence or disappearance of an electromagnetic force induced in the pickup coil 11. The A.G.V. 9 is also provided with a light receiving device 12 which faces the optical command transmitter 6 as it passes by and which is 2S electrically connected to the microcomputer mounted on the A.G.V. 9~
In the thus-constructed installation, the operation of the A.G.V. in accordance with the present invention is controlled on the basis of a flow chart such as that shown in Fig. 4.
That is, optimum travel speeds with respect to all of the production lines 1 (1', 1", 1"') (generally equal to the speeds at which conveyors are continuously moved if the production line work is performed by using conveyors) are previously input into the microcomputer mounted on the J~l , -- 8 ~
A.G.V. 9. After this preparation, the location to which the cart should travel is assigned by a controller (not shown) - step ~ . Thereafter, the unmanned cart 9 is loaded with a desired workload 13 (Fig. 3) at the workload entrance station 3 - step ~ , and is made to travel at a predetermined speed V0 along the travel guide wire 5 in the factory - step ~ .
The speed at which the unmanned cart 9 travels, while it is detecting by means of the pickup coils 10 the electromagnetic field produced by the travel guide wire 5, is set to be comparatively high as in the case of a conventional A.G.V., and the travel route is determined by the external controller.
When the A.G.V. 9 enters the production line 1 (1', 1", 1"~) - step Q, a speed command signal is issued from the optical command transmitter 6 provided in the command transmitting station No at the entrance end of the production line 1 (1', 1", 1"~ - step ~ . The A.G.V. 9 receives this command by the light receiving device 12, accesses an optimum travel speed Vl (V2, Y3, V4~ of the production line 1 (1', 1", 1"') stored in the microcomputer, regulates the rotational speed of the drive motor on the basis of this information by means of the controller and the rotary encoder, and thereby performs the desired travel - step ~ .
Since, as shown in Fig. 5, the constant value speed Vl at which the A.G.V. 9 has been set is substantially equal to the conveyor speed (where a conveyor system is used), the worker waiting at each of the stations Nl to N5 can perform desired assembling or packaging operations at a pace consistent with the movement of the A.G.V. 9 traveling at a low speed.
After assembling or packaging operations performed at the work stations Nl to N5 have been completed, the ,., , . ~ .
'' ' ' . I .. . ,' .
~ ........ -, , : , ,, -` :.
, ..
g A.G.V. 9 receives a command from the optical transmitter 6 of the command transmitting station No~ at the exit side -step ~ . The speed at which the cart travels is thereby returned to the speed VO - step ~ . When the A.G.V. 9 reaches the workload exit station 4, the work which has undergone the assembling or packaging operations is unloaded - step ~ . The cart travels again to the workload entrance station 3, and the above-described operation is thereafter repeated.
The workers engaged in the operations at the work stations Nl to N5 can stop as desired the A.G.V. 9, for example, in times of emergency. In this case, one of the hold switches 8 provided in the stations N1 to N5 is operated so that an electromagnetic field occurs around the start-stop command wire 5. The drive motor is thereby stopped through the medium of the pickup coil 11. When the hold switch 8 is turned off, the generation of the electromagnetic field is terminated, and the drive motor of the A.G.V. 9 is thereby started again.
Needless to say, the present invention is not limited to the above-described embodiment, and other various modifications and alterations are possible. For instance, the device for sending a command to change the travel speed of the A.G.V. on each production line and the device for receiving this command may be replaced with a bar code and a bar code reader. Also, a conventional station stop method may be combined with the system in accordance with the present invention as desired.
TITLE OF THE INVENTION
NETHOD OF CONTROLLING OPERATION OF AUTOMATED GUIDED
VEHICLE
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a method of controlling the operation of an Automated Guided Vehicle (hereinafter abbreviated to A.G.V.) used as a means of transportation for production line work performed in a machine manufacturing works.
Description of Prior Art In general, production line work in a machine manufacturing works such as an automobile manufacturing works is usually performed with a conveyor system. In particular, with respect to a production line work mainly performed by way of manual operations, the relevant operations are usually performed by using a conveyor system. This is because a well-paced performance, based on the continuous flow of a conveyor, is regarded as important.
However, a production line applied to a conventional conveyor system involves a number of work stages, and the length of the production line is inevitably quite considerable. The size of the installation is thus correspondingly increased and it is difficult to provide paths for the movement of workers and the supply of parts. Such a system is also defective in terms of adaptability to changes in the overall layout of the works.
The introduction of A.G.V.s to parts assembly lines or parts packaging lines is currently being eagerly studied as an alternative to the use of conveyor systems.
~. .
.
~ 3~3084 Examples of techniques allowing such applications are disclosed in Japanese Patent Laid-Open No. 60-137476, "AUTOMATION" (published by Nikkan Kogyo Shinbun Shia in 1986, Vol. 31, No. 8, pp 36 - 42), and "MATERIAL HANDLING
ENGINEERING" ~published by PENTON-IPC in USA, 1985, pp 52 - 56).
In all the techniques for introduction of A.G.V.s disclosed in these documents, the speed at which an A.G.V.
travels is constant, an~ an operation of assembling or packaging parts is performed each time the vehicle stops at a station for a predetermined period of time.
Consequently, such a vehicle system cannot serve as a way of maintaining a desired pace and cannot constantly maintain a certain level of working hours and production line speed, thus resulting in a lowering of production efficiency.
In the system disclosed in Japanese Patent Laid-Open No. 60-137476, the time for the stop at each station is controlled in accordance with the time taken by each work stage in a production line. In this system, lamps may be provided at each station in order to inform workers of the passage of working time or the time remaining for the given task. However, this system cannot serve to maintain a certain pace commensurate with the performance of production line work since the pace keeping function of this system does not become second nature to a person, like the continuous flow of a conveyor system.
There is a possibility that it will result in operations becoming non-uniform. There is also a problem in that the administrator or supervisor is not informed of the progress of operation and whether it is ahead of or behind in time relative to a set standard.
SUMMARY OF THE INVENTION
A general technical concern of the present .~
`: . '' ' , , , ' ,.: ' ' ,''`' `' ' , ' ~ .
., ' .
,. : .. ' :
invention is the solution to certain problems relating to the introduction of A.G.V.s to an assembly or packaging line based on the above-described conventional techniques, and an object of the present invention is to provide an improved method of controlling the operation of an A.G.V., a method of providing a pace keeping function similar to that of a conveyor system while utilizing the benefits of introducing A.G.V.s, and a method which also serves to positively improve the production ef f iciency, thereby making a substantial contribution to the field of production line transportation techniques.
Thus, the present invention provides a method of controlling the operation of an A.G.V. to carry workpieces along production lines to a plurality of successive work stations at a speed corresponding to a predetermined distinctive workpiece conveyor speed for the respective production line in a manufacturing area of a plant, comprising the steps of defining a boundary of the manufacturing area with a transportation line having a workload entrance station and a workload exit station:
providing a plurality of parallel spaced production lines;
within the defined boundary; providing a plurality of successively disposed work stations along each production line; connecting the transportation line and each production line by a guide wire provided in the manufacturing area floor; propelling the ~.G.V. at a transportation line speed by detecting a magnetic field generated continuously from the transportation line to each of the production lines and from each production line to the transportation line; generating a speed command signal adjacent the entrance and exit ends of each production line for controlling the A.G.V. entering and exiting a respective production line; storing on the A.G.V. speed data corresponding to a predetermined distinct workpiece conveyor speed for each production .:
: . .
~ - ~
. . .
line; each distinct workpiece conveyor speed being continuous and each being less than the transportation line speed through the work stations of each production line: each distinct workpiece conveyor speed being the desired speed for performing manufacturing operations at the work stations along each corresponding production line; detecting on the A.G.V. the generated speed command signals of the corresponding entrance and exit end of the respective production line; decreasing the speed of the ~.G.V. from the transportation line speed to the respectivQ stored speed for the corresponding production line until the speed of the A.G.V. is equal to the distinct workpiece conveyor speed in response to the generated speed command signal at the entrance end of a respective production line; propelling the A.G.V. at the corresponding stored distinct workpiece conveyor speed ~
along the production line continuously; and increasing the ;' speed of the A.G.V. to the speed of the transportation line speed in response to the generated speed command signal at the exit end of the corresponding production line.
The present invention enables a pace keeping function similar to that of a conveyor system while utilizing the benefits of introducing A.G.V., such as increase in the degree of freedom in relation to changes in the layout in the factory and improvement in space utilization efficiency, thereby positively improving the production efficiency of the production line wor~.
A system in accordance with the present invention is preferably designed such that a speed control device is mounted on the A.G.V. Optimum travel speeds with respect to all of the production lines having different line contacts are stored in the speed control device, and a speed change command is supplied from the outside to the speed control device so as to change the speed of the , A.G.V. to a set speed assigned to one of the production lines when the A.G.V. enters this line. This eliminates the need for the provision of a large installation such as a conveyor system and ensures that the system in S accordance with the present invention can be adapted to changes in the layout in the factory by simply changing the operation route of the A.G.V. Since the A.G.V. can always continuously travel at a constant and low speed in a production line, it effects a positive pace making performance equivalent to that of a conveyor system during the production line process.
The method of mounting the speed control device of the A.G.V., storing optimum travel speeds in the speed control device, and assigning to the A.G.V. the speed corresponding to a production line in which the vehicle travels, enables a type of A.G.V. to be used in a plurality of production lines, thereby increasing the degree of freedom relative to different types of production line as well as mass production of A.G.V.s and, hence, a reduction in installation costs.
The invention will hereinafter be described by way of example only and with reference to the accompanying drawings.
~RIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate an embodiment of the present invention;
Fig. 1 is a schematic plan view of a part of the layout of production lines in a factory;
Fig. 2 is a schematic plan view of the whole of the layout shown in Fig. l;
Fig. 3 is a schematic side view of an A.G.V.;
Fig. 4 is an operational flow chart of the A.G.V.;
and Fig. 5 graphically illustrates the speeds of the ,...
": .
,. . . , , . .. :. :
.
.
.
` 1 323084 unmanned cart at different production lines.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figs. 1 to 3, production lines 1 (1', 1", 1"') for parts assembly and packaging are provided in a factory.
Desired parts to be assembled or packed and devices used for desired operations are disposed along the production line 1 (1', 1", 1"l).
A workload entrance station 3 and a workload exit station 4 are disposed in desired positions on a floor 2.
A travel guide wire 5 is embedded in the floor 2 in such a manner that it forms a loop which connects the workload entrance station 3, the workload exit station 4, and the 15 production lines 1 (1', 1", 1"l). The travel guide wire 5 is connected to an oscillation amplifier (not shown) and is supplied with a low-frequency current of a desired frequency so that generates electromagnetic field around its ou~er circumference.
As shown in Fig. 1, speed command transmitting ~tations No and No~ are disposed at the upstream and downstream ends of the production line 1 (1', 1", 1"').
The region between the speed command transmitting stations No and Nol is sectioned into work stations Nl, N2, N3, N4 and N5. An optical command oscillator 6 is provided at each of the speed command transmitting stations No and Nol. A start-stop command guide wire 7 is embedded at each of the work stations Nl, N2, N3, N4 and N5 in such a manner that it extends across the travel guide wire 5 in the work line 1 (1', 1", 1"'). The start-stop command wire 7 is connected to an oscillator (not shown~ via a hold switch 8 and is supplied with a low-frequency current of a desired frequency different from that of the current supplied to the travel guide wire 5 so that it generates an electromagnetic field around its outer periphery.
... .
... . .:
An A.G.V. 9 has a drive motor ~not shown) (such as one connected to a rotary encoder of a high resolution type for velocity feedback and to a controller) capable of being speed-controlled with accuracy, and a microcomputer (not shown) provided as a speed controller. The rotation of the motor is controlled on the basis of information issued from the microcomputer so that it is regulated to a set speed.
A pair of left and right pickup coils 10 responsive to the electromagnetic field produced by the travel guide wire 5 and a pickup coil 11 responsive to the electromagnetic field produced by each start-stop command guide wire 7 are disposed on an outside surface of the A.G.V. 9. The pickup coils 10 are electrically connected to a steering device (not shown), and steering is performed on the basis of the difference between electromokive forces induced in the left and right pickup coils 10. The pickup coil 11 is electrically connected to a power switch of the drive motor, and the power supply to the drive motor is switched on or off in response to the occurrence or disappearance of an electromagnetic force induced in the pickup coil 11. The A.G.V. 9 is also provided with a light receiving device 12 which faces the optical command transmitter 6 as it passes by and which is 2S electrically connected to the microcomputer mounted on the A.G.V. 9~
In the thus-constructed installation, the operation of the A.G.V. in accordance with the present invention is controlled on the basis of a flow chart such as that shown in Fig. 4.
That is, optimum travel speeds with respect to all of the production lines 1 (1', 1", 1"') (generally equal to the speeds at which conveyors are continuously moved if the production line work is performed by using conveyors) are previously input into the microcomputer mounted on the J~l , -- 8 ~
A.G.V. 9. After this preparation, the location to which the cart should travel is assigned by a controller (not shown) - step ~ . Thereafter, the unmanned cart 9 is loaded with a desired workload 13 (Fig. 3) at the workload entrance station 3 - step ~ , and is made to travel at a predetermined speed V0 along the travel guide wire 5 in the factory - step ~ .
The speed at which the unmanned cart 9 travels, while it is detecting by means of the pickup coils 10 the electromagnetic field produced by the travel guide wire 5, is set to be comparatively high as in the case of a conventional A.G.V., and the travel route is determined by the external controller.
When the A.G.V. 9 enters the production line 1 (1', 1", 1"~) - step Q, a speed command signal is issued from the optical command transmitter 6 provided in the command transmitting station No at the entrance end of the production line 1 (1', 1", 1"~ - step ~ . The A.G.V. 9 receives this command by the light receiving device 12, accesses an optimum travel speed Vl (V2, Y3, V4~ of the production line 1 (1', 1", 1"') stored in the microcomputer, regulates the rotational speed of the drive motor on the basis of this information by means of the controller and the rotary encoder, and thereby performs the desired travel - step ~ .
Since, as shown in Fig. 5, the constant value speed Vl at which the A.G.V. 9 has been set is substantially equal to the conveyor speed (where a conveyor system is used), the worker waiting at each of the stations Nl to N5 can perform desired assembling or packaging operations at a pace consistent with the movement of the A.G.V. 9 traveling at a low speed.
After assembling or packaging operations performed at the work stations Nl to N5 have been completed, the ,., , . ~ .
'' ' ' . I .. . ,' .
~ ........ -, , : , ,, -` :.
, ..
g A.G.V. 9 receives a command from the optical transmitter 6 of the command transmitting station No~ at the exit side -step ~ . The speed at which the cart travels is thereby returned to the speed VO - step ~ . When the A.G.V. 9 reaches the workload exit station 4, the work which has undergone the assembling or packaging operations is unloaded - step ~ . The cart travels again to the workload entrance station 3, and the above-described operation is thereafter repeated.
The workers engaged in the operations at the work stations Nl to N5 can stop as desired the A.G.V. 9, for example, in times of emergency. In this case, one of the hold switches 8 provided in the stations N1 to N5 is operated so that an electromagnetic field occurs around the start-stop command wire 5. The drive motor is thereby stopped through the medium of the pickup coil 11. When the hold switch 8 is turned off, the generation of the electromagnetic field is terminated, and the drive motor of the A.G.V. 9 is thereby started again.
Needless to say, the present invention is not limited to the above-described embodiment, and other various modifications and alterations are possible. For instance, the device for sending a command to change the travel speed of the A.G.V. on each production line and the device for receiving this command may be replaced with a bar code and a bar code reader. Also, a conventional station stop method may be combined with the system in accordance with the present invention as desired.
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of controlling the operation of an automated guided vehicle A.G.V. to carry workpieces along production lines to a plurality of successive work stations at a speed corresponding to a predetermined distinctive workpiece conveyor speed for the respective production line in a manufacturing area of a plant, comprising the steps of:
defining a boundary of the manufacturing area with a transportation line having a workload entrance station and a workload exit station;
providing a plurality of parallel spaced production lines, within the defined boundary;
providing a plurality of successively disposed work stations along each production line;
connecting the transportation line and each production line by a guide wire provided in the manufacturing area floor;
propelling the A.G.V. at a transportation line speed by detecting a magnetic field generated continuously from the transportation line to each of the production lines and from each production line to the transportation line;
generating a speed command signal adjacent the entrance and exit ends of each production line for controlling the A.G.V. entering and exiting a respective production line;
storing on the A.G.V. speed data corresponding to a predetermined distinct workpiece conveyor speed for each production line; each distinct workpiece conveyor speed being continuous and each being less than the transportation line speed through the work stations of each production line; each distinct workpiece conveyor speed being the desired speed for performing manufacturing operations at the work stations along each corresponding production line;
detecting on the A.G.V. the generated speed command signals of the corresponding entrance and exit end of the respective production line;
decreasing the speed of the A.G.V. from the transportation line speed to the respective stored speed for the corresponding production line until the speed of the A.G.V. is equal to the distinct workpiece conveyor speed in response to the generated speed command signal at the entrance end of a respective production line;
propelling the A.G.V. at the corresponding stored distinct workpiece conveyor speed along the production line continuously; and increasing the speed of the A.G.V. to the speed of the transportation line speed in response to the generated speed command signal at the exit end of the corresponding production line.
defining a boundary of the manufacturing area with a transportation line having a workload entrance station and a workload exit station;
providing a plurality of parallel spaced production lines, within the defined boundary;
providing a plurality of successively disposed work stations along each production line;
connecting the transportation line and each production line by a guide wire provided in the manufacturing area floor;
propelling the A.G.V. at a transportation line speed by detecting a magnetic field generated continuously from the transportation line to each of the production lines and from each production line to the transportation line;
generating a speed command signal adjacent the entrance and exit ends of each production line for controlling the A.G.V. entering and exiting a respective production line;
storing on the A.G.V. speed data corresponding to a predetermined distinct workpiece conveyor speed for each production line; each distinct workpiece conveyor speed being continuous and each being less than the transportation line speed through the work stations of each production line; each distinct workpiece conveyor speed being the desired speed for performing manufacturing operations at the work stations along each corresponding production line;
detecting on the A.G.V. the generated speed command signals of the corresponding entrance and exit end of the respective production line;
decreasing the speed of the A.G.V. from the transportation line speed to the respective stored speed for the corresponding production line until the speed of the A.G.V. is equal to the distinct workpiece conveyor speed in response to the generated speed command signal at the entrance end of a respective production line;
propelling the A.G.V. at the corresponding stored distinct workpiece conveyor speed along the production line continuously; and increasing the speed of the A.G.V. to the speed of the transportation line speed in response to the generated speed command signal at the exit end of the corresponding production line.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000566476A CA1323084C (en) | 1988-05-11 | 1988-05-11 | Method of controlling operation of automated guided vehicle |
| US07/439,010 US4993507A (en) | 1988-05-11 | 1989-11-20 | Method of controlling operation of automated guided vehicle |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US19272088A | 1988-05-11 | 1988-05-11 | |
| CA000566476A CA1323084C (en) | 1988-05-11 | 1988-05-11 | Method of controlling operation of automated guided vehicle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1323084C true CA1323084C (en) | 1993-10-12 |
Family
ID=25671890
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000566476A Expired - Fee Related CA1323084C (en) | 1988-05-11 | 1988-05-11 | Method of controlling operation of automated guided vehicle |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1323084C (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10589931B2 (en) | 2016-09-30 | 2020-03-17 | Staples, Inc. | Hybrid modular storage fetching system |
| US10683171B2 (en) | 2016-09-30 | 2020-06-16 | Staples, Inc. | Hybrid modular storage fetching system |
| US10803420B2 (en) | 2016-09-30 | 2020-10-13 | Staples, Inc. | Hybrid modular storage fetching system |
| US11084410B1 (en) | 2018-08-07 | 2021-08-10 | Staples, Inc. | Automated guided vehicle for transporting shelving units |
| US11119487B2 (en) | 2018-12-31 | 2021-09-14 | Staples, Inc. | Automated preparation of deliveries in delivery vehicles using automated guided vehicles |
| US11124401B1 (en) | 2019-03-31 | 2021-09-21 | Staples, Inc. | Automated loading of delivery vehicles |
| US11180069B2 (en) | 2018-12-31 | 2021-11-23 | Staples, Inc. | Automated loading of delivery vehicles using automated guided vehicles |
| US11590997B1 (en) | 2018-08-07 | 2023-02-28 | Staples, Inc. | Autonomous shopping cart |
| US11630447B1 (en) | 2018-08-10 | 2023-04-18 | Staples, Inc. | Automated guided vehicle for transporting objects |
-
1988
- 1988-05-11 CA CA000566476A patent/CA1323084C/en not_active Expired - Fee Related
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10589931B2 (en) | 2016-09-30 | 2020-03-17 | Staples, Inc. | Hybrid modular storage fetching system |
| US10683171B2 (en) | 2016-09-30 | 2020-06-16 | Staples, Inc. | Hybrid modular storage fetching system |
| US10803420B2 (en) | 2016-09-30 | 2020-10-13 | Staples, Inc. | Hybrid modular storage fetching system |
| US11697554B2 (en) | 2016-09-30 | 2023-07-11 | Staples, Inc. | Hybrid modular storage fetching system |
| US11702287B2 (en) | 2016-09-30 | 2023-07-18 | Staples, Inc. | Hybrid modular storage fetching system |
| US11893535B2 (en) | 2016-09-30 | 2024-02-06 | Staples, Inc. | Hybrid modular storage fetching system |
| US11084410B1 (en) | 2018-08-07 | 2021-08-10 | Staples, Inc. | Automated guided vehicle for transporting shelving units |
| US11590997B1 (en) | 2018-08-07 | 2023-02-28 | Staples, Inc. | Autonomous shopping cart |
| US11630447B1 (en) | 2018-08-10 | 2023-04-18 | Staples, Inc. | Automated guided vehicle for transporting objects |
| US11119487B2 (en) | 2018-12-31 | 2021-09-14 | Staples, Inc. | Automated preparation of deliveries in delivery vehicles using automated guided vehicles |
| US11180069B2 (en) | 2018-12-31 | 2021-11-23 | Staples, Inc. | Automated loading of delivery vehicles using automated guided vehicles |
| US11124401B1 (en) | 2019-03-31 | 2021-09-21 | Staples, Inc. | Automated loading of delivery vehicles |
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