JPH09309607A - Stacker crane for automatic warehouse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slacker crane for an automatic warehouse in which a safe operation can be carried out and a reduction in operation rate can be prevented. SOLUTION: Both a first running encoder A and a second running encoder B are directly connected to a shaft of driven wheel and a control device 21 compares counted values of these encoders so as to monitor an abnormal state of each of the encoders. In the case that an abnormal state occurs at each of the encoders, it is caused to run by a running driving device 6 in a specified segment, the counted values of both encoders are compared with the counted values under a normal state of it, thereby it is discriminated which encoder shows an abnormal state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stacker crane for an automatic warehouse, and more particularly to a stacker crane for detecting a traveling position of a crane and an ascending / descending position of a carriage by using a traveling encoder and a lifting encoder.

[0002]

2. Description of the Related Art In recent years, automatic warehouses have come to be widely used due to the consolidation of distribution bases for the purpose of improving distribution costs and distribution efficiency, and the spread of high-mix low-volume production accompanying diversification of user needs. . In an automatic warehouse, a stacker crane as shown in FIG. 7 is used to put a stored item in and out of a warehouse rack. The traveling body 1 of the stacker crane is composed of two upright masts 2 and 3, and a lower frame 4 and an upper frame 5 that horizontally connect the lower and upper parts of these masts, respectively.

The lower frame 4 is provided with drive wheels and driven wheels (not shown) which are driven by the traveling drive device 6, and these drive wheels and driven wheels ride on a lower rail 7 arranged on the floor. There is. On the other hand, the upper frame 5 is provided with a guide roller 9 slidably engaged with an upper rail 8 arranged immediately above the lower rail 7. Further, the traveling main body 1 is provided with a hoisting drum 11 which is rotationally driven by the hoisting and driving device 10, and a carriage which hoists and lowers along the masts 2 and 3 at one end of the wire 12 wound on the hoisting drum 11. 13 are suspended.

The traveling drive device 6 drives the drive wheels according to a traveling speed pattern of a preset deceleration control, whereby the traveling main body 1 travels horizontally along the lower rail 7 and the upper rail 8. As shown in FIG. 8, a traveling encoder 15 for detecting a traveling position is directly connected to the shaft of the driven wheel 14, and whether the predetermined deceleration control is normally performed by the traveling encoder 15 or not. Is monitored.

Similarly, the lifting drive device 10 drives the winding drum 11 in accordance with a preset lifting speed pattern of deceleration control, whereby the carriage 13 causes the wire 12 to move.
Although it goes up and down along the masts 2 and 3 via the roller, as shown in FIG. 9, an elevator encoder 17 for detecting the rotational position of the roller 11 is provided on the peripheral portion of the roller 11 via the roller 16. The elevating encoder 17 monitors whether or not the predetermined deceleration control is normally performed.

[0006]

However, conventionally, when the traveling encoder 15 for monitoring the deceleration control of traveling fails, the traveling main body 1 collides with the ends of the lower rail 7 and the upper rail 8 and is automatically operated. There is a risk that the warehouse may be damaged, and the system of the entire automated warehouse must be stopped for a long time in order to repair or replace the defective traveling encoder 15, which causes a problem that the operating rate decreases.

On the other hand, if the raising / lowering encoder 17 for monitoring the deceleration control of the raising / lowering fails, the carriage 13 may collide with the ends of the masts 2 and 3 and be damaged. In order to repair or replace the lifting encoder 17, the system of the entire automated warehouse had to be stopped for a long time.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide an automatic warehouse stacker crane which can be operated more safely and can prevent a decrease in operating rate. To aim.

[0009]

A stacker crane for an automatic warehouse according to the present invention is a stacker crane for an automatic warehouse that travels on a floor by a traveling drive device. A travel encoder and a control device for controlling the travel drive device based on the count values of the first and second travel encoders are provided.

The controller determines whether or not an abnormality has occurred in these encoders on the basis of the difference between the count values of the first and second traveling encoders. The drive unit is driven to drive the vehicle in a specified section, and it is determined which encoder is abnormal from the count values of the first and second running encoders at this time, and the other normal encoder is used to drive the drive unit. It is also possible to configure to make an emergency operation by.

Further, another stacker crane for an automatic warehouse according to the present invention is a stacker crane for an automatic warehouse in which an elevator drive device elevates and lowers a carriage along a vertical mast. A second lifting encoder and a control device that controls the lifting drive device based on the count values of the first and second lifting encoders are provided.

The control device determines whether or not an abnormality has occurred in these encoders based on the difference between the count values of the first and second elevator encoders. If it is determined that an abnormality has occurred, the controller moves up and down. By driving the driving device, the carriage is moved up and down over a specified section, and the first and second carriages
It is also possible to determine which one of the encoders is abnormal from the count value of the lifting / lowering encoder and use the other normal encoder so that the lifting / lowering drive device performs an emergency operation.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. An automatic warehouse stacker crane according to an embodiment of the present invention has substantially the same configuration as the conventional stacker crane shown in FIG. 7. That is, two upright masts 2 and 3 and a lower frame 4 horizontally connecting the lower and upper parts of these masts, respectively.
And a lower frame 4 on which a driving wheel (not shown) driven by a traveling drive device 6 and driven wheels are provided and which is mounted on a lower rail 7. The upper frame 5 is provided with a guide roller 9 slidably engaged with an upper rail 8 arranged directly above the lower rail 7. In addition, the lifting drive device 10
The wire 12 on the winding drum 11 that is driven to rotate by
Is wound, and at one end of the wire 12, a carriage 13 that is moved up and down along the masts 2 and 3 is suspended.

In the stacker crane according to this embodiment, as shown in FIG. 1, first and second traveling encoders A and B for detecting the rotational position of the driven wheel 14 of the driven wheel 14 shaft. Are directly connected to each other coaxially.
As shown in FIG. 2, these encoders A and B are respectively connected to the control device 21, and the control device 21 is electrically connected to the traveling motor 23 via the inverter 22 in the traveling drive device 6. There is. Drive wheels (not shown) are rotated by the traveling motor 23.

Next, the traveling operation of the stacker crane according to this embodiment will be described with reference to the flowchart of FIG. The control device 21 controls the traveling drive device 6 according to the traveling speed pattern of the preset deceleration control, thereby driving the drive wheels to travel the traveling main body 1 horizontally along the lower rail 7 and the upper rail 8. Let During this traveling, the first and second wheels directly connected to the shaft of the driven wheel 14
The driven wheels 14 by the traveling encoders A and B, respectively.
The rotational position of is detected.

Therefore, the control device 21 calculates the difference | ab | between the count value a of the first traveling encoder A and the count value b of the second traveling encoder B in step S1, and this difference is calculated. And the allowable value R are compared. Since the first and second traveling encoders A and B are both directly connected to the shaft of the driven wheel 14, the count values a and b of both of them are normally set.
Are the same as each other. The allowable value R is set to a value slightly larger than the measurement error that can occur in the normal first and second traveling encoders A and B, and if the difference between the count values a and b is within the measurement error. It does not exceed the allowable value R.

Here, if one of the running encoders fails, a difference occurs between the count value and the count value of the other normal running encoder, so that the difference between these count values exceeds the allowable value R. become. Therefore, when it is determined in step S1 that the difference | a−b | exceeds the allowable value R, the process proceeds to step S2, in which an abnormality of the encoder is displayed on a crane control panel or the like (not shown) connected to the stacker crane. The traveling of the crane is stopped, and in this state, the recovery instruction is waited in step S3.

When the operator receives an instruction to restore from the crane control panel in step S3, the control device 21 controls the traveling drive device 6 in step S4 to drive the crane at a low speed for a predetermined predetermined section. Let The specified section may be any section on the lower rail 7, but since the lower frame 4 of the traveling main body 1 is provided with a traveling sensor arranged on the floor along the lower rail 7 to detect traveling dogs. A predetermined section may be defined as a predetermined section between two traveling dogs, and the traveling sensor may be used to travel at a low speed between the traveling dogs. Further, it is assumed that the normal count values a0 and b0 of the first and second traveling encoders A and B when traveling in the specified section are measured in advance.

In this way, the vehicle travels in the specified section in step S4, and in step S5, the difference between the count value a1 of the first traveling encoder A at this time and the previously measured normal count value a0 | a1-a0 | is calculated, and it is determined whether or not this difference is less than or equal to the determination value P. Difference |
If a1-a0 | exceeds the determination value P, it is determined that the first traveling encoder A is abnormal, the process proceeds to step S6, and the fact that the encoder A is abnormal is displayed on the crane control panel or the like. .

Similarly, the count value b1 of the second traveling encoder B when the vehicle travels in the specified section in step S7.
And the difference | b1-b0 | between the normal count value b0 measured in advance are calculated, and it is determined whether or not this difference is less than or equal to the determination value P. If the difference | b1-b0 | exceeds the determination value P, it is determined that the second traveling encoder B is abnormal, and the process proceeds to step S8 to inform the crane control panel that the encoder B is abnormal. indicate.

Note that the judgment value P is set to a value that allows for a measurement error in traveling within the specified section, like the above-mentioned allowable value R, and the difference in count values | a1-a0 | or | b1- If b0 | is within the measurement error, the judgment value P is not exceeded.

As described above, whether or not each of the encoders A and B is abnormal can be recognized. Therefore, in the subsequent step S9, the first and second
When only one of the traveling encoders A and B is abnormal, the traveling drive device 6 is used to temporarily continue the operation of the crane using the other normal traveling encoder.

By comparing the count values of the first and second traveling encoders in this way, the abnormality of the encoder can be easily monitored. When an abnormality occurs, it is possible to determine which encoder has an abnormality by running in a specified section and comparing the count values of both encoders with the count value at the time of normal operation. It becomes possible to continue the operation temporarily. Therefore, the reliability of the encoder is improved, and the automatic warehouse system can be operated safely and efficiently.

Instead of directly connecting the two traveling encoders A and B to the shaft of the driven wheel 14, the traveling position of the crane can be detected by directly contacting the measuring roller of each traveling encoder with the traveling rail. In addition, each of the traveling encoders is connected to the shaft of the traveling motor 23 or the traveling motor 23.
It is also possible to detect the traveling position of the crane by attaching it to the shaft of a speed reducer connected to.

In the above embodiment, the two traveling encoders A and B were directly connected to the shafts of the driven wheels 14 to improve the safety function for traveling of the crane. However, as shown in FIG. It is also possible to provide the first and second raising and lowering encoders C and D on the periphery of the roller through rollers 24 and 25 having the same diameter, and to detect the rotational position of the winding drum 11 by these encoders C and D. As shown in FIG. 5, the first and second lifting encoders C and D are respectively connected to the control device 26, and the control device 26 rotates the hoisting drum 11 via the inverter 27 in the lifting drive device 10. Is electrically connected to a lifting motor 28.

By using such two lifting encoders C and D, the lifting operation of the carriage 13 can be performed in the same manner as the traveling operation of the stacker crane described above. This elevating operation is shown in the flowchart of FIG. 6, but it is the same as the traveling operation shown in FIG. That is, the control device 26 controls the lifting drive device 10 according to a preset lifting speed pattern of deceleration control, thereby driving the hoisting drum 11 to move the carriage 13 to the masts 2 and 3.
Move up and down along. During this ascending / descending, the rotational position of the hoisting drum 11 is detected by the first and second hoisting encoders C and D arranged on the peripheral portion of the hoisting drum 11, respectively.

Therefore, the control device 26 controls the step S11.
Then, the difference | c−d | between the count value c of the first elevating encoder C and the count value d of the second elevating encoder D is calculated, and this difference is compared with the allowable value R. here,
If one of the lift encoders fails, a difference occurs between the count value and the count value of the other normal lift encoder. Therefore, the difference between these count values is the allowable value R.
Will be exceeded. Therefore, in step S11, the difference |
If it is determined that cd− exceeds the allowable value R, the process proceeds to step S12, an abnormality of the lifting encoder is displayed on the crane control panel, the rotation of the hoisting drum 11 is stopped, and in this state, step S13. Wait for recovery instructions.

When the operator receives an instruction to restore from the crane control panel in step S13, step S14
Then, the control device 26 controls the lifting drive device 10 to drive the carriage 13 at a low speed for a predetermined defined section, and measures the count value c1 of the first lifting encoder C at this time in advance in step S15. The difference | c1-c0 | with respect to the stored normal count value c0 is calculated, and it is determined whether or not this difference is less than or equal to the determination value P. Difference | c1
If -c0 | exceeds the determination value P, it is determined that the first lifting / lowering encoder C is abnormal, and the process proceeds to step S16 to display that the encoder C is abnormal on the crane control panel.

Similarly, the count value d of the second elevator encoder D when the vehicle travels in the specified section in step S17.
The difference | d1-d0 | between 1 and the previously measured normal count value d0 is calculated, and it is determined whether or not this difference is less than or equal to the determination value P. The difference | d1-d0 | is the judgment value P
If it exceeds, it is determined that the second lifting / lowering encoder D is abnormal, the process proceeds to step S18, and the fact that the encoder D is abnormal is displayed on the crane control panel.

As described above, whether or not each of the encoders C and D is abnormal can be recognized. Therefore, in a succeeding step S19, when only one of the first and second elevating encoders C and D is abnormal, the other normal elevating encoder is used to temporarily move the carriage 13 by the elevating drive device 10. Continue the lifting operation of.

By comparing the count values of the first and second lifting encoders in this way, it is possible to easily monitor the abnormality of the encoder. When an abnormality occurs, it is possible to determine which encoder has an abnormality by running in a specified section and comparing the count values of both encoders with the count value at the time of normal operation. It becomes possible to continue the operation temporarily. Therefore, the reliability of the encoder is improved, and the automatic warehouse system can be operated safely and efficiently.

Instead of providing the two lifting encoders C and D on the periphery of the winding drum 11, the measuring roller of each lifting encoder is brought into direct contact with the mast 2 or 3 to detect the lifting position of the carriage 13. Alternatively, each elevating encoder can be attached to the shaft of the elevating motor 28 or the shaft of a speed reducer connected to the elevating motor 28 to detect the elevating position of the carriage 13.

In addition, the first and second traveling encoders are provided and the first and second elevating encoders are provided to improve the safety of the traveling operation and the elevating operation, respectively, and to improve the operation rate of the automatic warehouse system. It is also possible to improve.

[Brief description of drawings]

FIG. 1 is a diagram showing a traveling encoder provided on driven wheels of an automatic warehouse stacker crane according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control system of the traveling drive system in the embodiment.

FIG. 3 is a flowchart illustrating the operation of the embodiment.

FIG. 4 is a diagram showing a lifting encoder provided on a hoisting drum of an automatic warehouse stacker crane according to another embodiment.

FIG. 5 is a block diagram showing a control system of a lifting drive device according to another embodiment.

FIG. 6 is a flowchart showing the operation of another embodiment.

FIG. 7 is a perspective view showing a stacker crane for an automated warehouse.

FIG. 8 is a diagram showing a traveling encoder provided on driven wheels of a conventional stacker crane.

FIG. 9 is a diagram showing a lifting encoder provided on a winding drum of a conventional stacker crane.

[Explanation of symbols]

 1 Traveling Main Body 2, 3 Mast 4 Lower Frame 5 Upper Frame 6 Traveling Drive Device 10 Lifting Drive Device 11 Hoisting Drum 12 Wire 13 Carriage 14 Driven Wheels 21, 26 Control Device 24, 25 Roller A First Traveling Encoder B 2nd Travel encoder C 1st lift encoder D 2nd lift encoder

Claims (4)

[Claims] 1. A stacker crane for an automated warehouse that travels on a floor by a travel drive device, comprising: a first and second travel encoders for detecting travel positions of cranes; and a first and second travel encoders. A stacker crane for an automatic warehouse, comprising: a control device that controls a traveling drive device based on a count value. 2. The control device determines whether or not an abnormality has occurred in these encoders based on the difference between the count values of the first and second traveling encoders, and when it determines that an abnormality has occurred, The traveling section is driven by the traveling drive unit to determine which encoder is abnormal from the count values of the first and second traveling encoders at this time, and the traveling drive is performed using the other normal encoder. The stacker crane according to claim 1, wherein the stacker crane is operated by a device. 3. A stacker crane for an automatic warehouse, wherein a carriage is lifted and lowered by a lift drive device along a vertical mast. First and second positions for detecting the lift position of the carriage, respectively.
2. An automatic warehouse stacker crane comprising: a lifting encoder and a controller for controlling the lifting drive device based on the count values of the first and second lifting encoders. 4. The control device determines whether or not an abnormality has occurred in these encoders based on the difference between the count values of the first and second lifting encoders, and when it determines that an abnormality has occurred, When the carriage is moved up and down over a specified section by driving the lifting drive device, the first and second carriages
4. The stacker crane according to claim 3, wherein it is determined which encoder is abnormal from the count value of the lifting / lowering encoder, and the other normal encoder is used to perform an emergency operation by the lifting / lowering drive device.