JP3596740B2 - Speed control device of moving object in stacker crane - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a stacker crane used in an automatic warehouse or the like, and particularly to a device for controlling the speed of a moving body.
[0002]
[Prior art]
FIG. 7 is a perspective view showing a schematic structure of a conventional stacker crane. In the figure, a stacker crane 1 has a pair of masts 2, and a carriage 3 for carrying a load is provided along the masts 2 so as to be able to move up and down in the direction of arrow P. The carriage 3 is equipped with a fork 4 for performing a cargo handling operation.
[0003]
Reference numerals 5 and 6 denote sensors provided on the sides of the carriage 3, and are constituted by, for example, reflection-type photoelectric sensors. Reference numeral 7 denotes a forced deceleration dog provided on an upper portion of the mast 2 and is formed of an elongated plate-like member extending in the vertical direction of the carriage 3. Reference numeral 8 denotes a forced deceleration dog provided at the lower part of the mast 2 and, like the dog 7, is formed of an elongated plate-like member extending in the elevating direction of the carriage 3.
[0004]
Reference numeral 9 denotes a lifting drive for raising and lowering the carriage 3, which is composed of a motor and the like. Reference numeral 10 denotes a traveling rail on which the traveling vehicle 15 of the crane 1 travels in the direction of arrow Q. Reference numeral 11 denotes a traveling drive device provided at an end of the traveling vehicle 15.
[0005]
A guide rail 12 is provided above the crane 1, and the guide roller 13 is guided by the guide rail 12 when the traveling vehicle 15 travels on the traveling rail 10. An upper frame 14 supports the guide roller 13 and is connected to the mast 2. Reference numeral 16 denotes a crane panel mounted on the crane 1 to control the carriage 3, and 17 denotes a controller installed on the floor and controlling the entire warehouse.
[0006]
In the crane 1 having the above configuration, the carriage 3 is moved at a predetermined speed between the upper end position and the lower end position by the lifting / lowering drive device 9. However, in order to stop the carriage 3 at the upper end position or the lower end position, the carriage 3 3 needs to be decelerated before them. For this reason, the dogs 7 and 8 are detected by the sensors 5 and 6, and the deceleration control of the carriage 3 is performed based on the detection signals.
[0007]
That is, when the carriage 3 moves up and the sensor 5 approaches the lower end of the dog 7, the sensor 5 detects the dog 7, and from this point on, the rotation speed of the motor of the elevation drive device 9 decreases and the carriage 3 starts to decelerate. The speed gradually decreases and stops at the upper end position. Further, when the carriage 3 moves down and the sensor 6 approaches the upper end of the dog 8, the sensor 6 detects the dog 8, and from this point on, the rotation speed of the motor of the lifting / lowering drive device 9 decreases, and the carriage 3 starts to decelerate. The speed gradually decreases and stops at the lower end position.
[0008]
[Problems to be solved by the invention]
By the way, in order to surely stop the carriage 3 at the end position, it is necessary to decelerate earlier as the speed of the carriage 3 increases. For this reason, conventionally, the lengths of the dogs 7 and 8 are set in accordance with the maximum speed of the carriage 3, and the lengths of the dogs 7 and 8 are considerably long.
[0009]
However, the carriage 3 does not always move up and down at the maximum speed, and may be driven at a lower speed depending on the setting. Therefore, when the carriage 3 moves up and down relatively slowly, the time point at which the carriage 3 decelerates may be delayed. However, in the above-described conventional apparatus, even when the carriage 3 is at a low speed, the deceleration control is uniformly performed when the sensors 5 and 6 detect the forced deceleration dogs 7 and 8, so that the deceleration is started from the point where the deceleration is not necessary. As a result, the deceleration period becomes longer, which is an obstacle in shortening the cycle time (reciprocating time of the carriage 3).
[0010]
The present invention solves the above-described problems, and can reduce the cycle time by eliminating unnecessary deceleration of the moving body, and can reduce the length of the dog in a stacker crane that can shorten the dog length. It is an object to provide a speed control device.
[0011]
[Means for Solving the Problems]
In order to solve the above problem, the present invention determines whether or not the speed of the moving body is equal to or higher than a predetermined value when the sensor detects the forced deceleration dog, and determines whether the speed of the moving body is equal to or higher than the predetermined value. Controls emergency stop of the moving body, and moves the moving body at the same speed when the speed of the moving body is lower than a predetermined value.
[0012]
By doing so, if the speed of the moving body is lower than the predetermined value at the time when the dog is detected, the moving body moves at the same speed, so that unnecessary deceleration is avoided. On the other hand, if the speed of the moving body is equal to or higher than the predetermined value at the time when the dog is detected, the moving body stops at an emergency. Therefore, even if the dog is short, the moving body can be stopped at the end position.
[0013]
In the present invention, the speed can be more finely controlled by determining the speed of the moving body in a plurality of stages. In this case, the forced deceleration dog may include a plurality of detection units for determining whether or not the speed of the moving body is equal to or higher than a predetermined value, and a detection unit for forcibly stopping the moving body.
[0014]
For example, the forcible deceleration dog is provided with a first detection unit for determining whether or not the speed of the moving body is equal to or higher than a first predetermined value on the tip side and a speed of the moving body which is in the middle portion and the speed of the moving body is equal to the second speed. A second detection unit for determining whether or not the value is equal to or more than a second predetermined value smaller than the predetermined value of 1; and a third detection unit on the terminal side for forcibly stopping the moving body. Each of these detection units can be formed in a shape identified by the sensor.
[0015]
As the sensor, a photoelectric sensor having two optical axes may be used, and each detection unit of the forced deceleration dog may be identified from a combination pattern of shielding and transmission of each optical axis.
[0016]
Further, the moving body may be a carriage that moves up and down in a vertical direction, or a traveling vehicle that runs in a horizontal direction.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a schematic structure of a stacker crane according to an embodiment of the present invention. 1, the same parts as those in FIG. 7 are denoted by the same reference numerals.
[0018]
1 is a stacker crane, 2 is a pair of masts, 3 is a carriage provided so as to be able to move up and down in the direction of arrow P along the mast 2, 4 is a fork mounted on the carriage 3, and 9 is a carriage 3. Lifting drive device comprising a motor or the like for raising and lowering the vehicle, 10 is a travel rail, 11 is a travel drive device provided at the end of the traveling vehicle 15, 12 is a guide rail disposed above the crane 1, 13 is a guide roller guided by the guide rail 12, 14 is an upper frame supporting the guide roller 13, 15 is a traveling vehicle traveling in the direction of arrow Q along the traveling rail 10, and 16 is a crane panel mounted on the crane 1. , 17 are controllers installed on the floor, and the above configuration is the same as that of FIG.
[0019]
Reference numerals 18a and 18b denote sensors attached to the sides of the carriage 3, which are composed of a transmission type two-optical axis photoelectric sensor described later. Reference numeral 19 denotes a forced deceleration dog provided at an upper portion of the mast 2 and is formed of a step-like member extending in a direction in which the carriage 3 moves up and down. Reference numeral 20 denotes a forced deceleration dog provided at a lower portion of the mast 2 and, like the dog 19, is formed of a stepped member extending in the elevating direction of the carriage 3. The details of the dogs 19 and 20 will be described later.
[0020]
FIG. 2 is a perspective view of the sensors 18a and 18b (hereinafter collectively referred to as 18). Sensor 18 is a two-beam photoelectric sensor of a transmission type in which the U-shaped, the optical axis X connecting the optical axis X ₁ connecting the light emitting element 21a and the light receiving element 21b, the light projecting element 22a and the light receiving element 22b _{It has two} optical axes. The two-optical axis photoelectric sensor outputs a detection signal when the optical axis X ₁ and the optical axis X ₂ are blocked by an object to be detected (dog).
[0021]
FIG. 3 is a diagram for explaining the operation when the speed of the carriage is controlled by the sensor and the dog. Here, the dog 19 on the upper side of FIG. 1 is shown, and the case where the speed of the carriage 3 in the ascending process is controlled is illustrated. The dog 19 includes a first detection section 191 on the distal end side, a second detection section 192 on the intermediate section, and a third detection section 193 on the end side. The first detection unit 191 is formed in a narrow shape with the left side of the figure cut out. The second detection unit 192 is formed to be wider so as to have a width approximately twice that of the first detection unit 191. The third detector 193 is formed in a narrow shape with the right side of the figure cut out.
[0022]
By forming the dog 19 in such a shape, the sensor 18 (in this case, the sensor 18a in FIG. 1) can identify the detection units 191 to 193. That is, when the sensor 18 approaches A (the first forced deceleration position) in FIG. 3, the optical axis X ₁ is blocked by the first detector 191, but the optical axis X ₂ is not blocked, so the optical axis X ₁ is not blocked. There ON, the optical axis _{X 2} is turned OFF. Also, when the sensor 18 approaches B (second forced deceleration position) in FIG. 3, both the optical axis X ₁ and the optical axis X ₂ are blocked by the second detection unit 192, so that the optical axis X ₁ is ON and the optical axis X ₁ is ON. X ₂ also becomes the ON state. Further, when the sensor 18 is approaching the C (forced stop position) in FIG. 3, the light axis _{X 2} is intercepted by the third detecting unit 193, since the optical axis _{X 1} is not shielded, the optical axis _{X 1} is OFF , the optical axis _{X 2} is in an ON state.
[0023]
In this way, it is possible to identify each detector 191-193 of the dog 19 from the combination pattern of the shielding and transmission of the optical axes _X 1, _{X 2.} As a result, since it is possible to determine that the sensor 18 has reached the positions A, B, and C in FIG. 3, the speed of the carriage 3 at each of the positions A, B, and C can be controlled using this.
[0024]
FIG. 4 is a flowchart showing the speed control operation. Hereinafter, the speed control will be described with reference to FIGS. 3, when the sensor 18 detects the first detection part 191 of the dog reaches the position of A (step S1 in FIG. 4), the rising speed of the carriage 3 at this point is whether or not a predetermined value V ₁ or more It is determined (step S2). If it speeds the predetermined value V ₁ or more, it is determined that the velocity anomaly perform an emergency stop (step S7). On the other hand, speed increase as it speeds is less than V _1. In the latter case, the carriage 3 is decelerated toward the stop at the upper end position before reaching the position B.
[0025]
Next, when the sensor 18 the carriage 3 continues to rise detects the second detection unit 192 of the dog reaches the position of B (step S3), and if the rising speed of the carriage 3 at this point the predetermined value V ₂ or more It is determined whether or not it is (step S4). Here, V ₂ <V ₁ . If it speeds the predetermined value V ₂ or more, it is determined that the speed abnormality perform an emergency stop (step S7). On the other hand, speed increase as it speeds is less than V _2.
[0026]
Next, when the sensor 18 reaches the position C and detects the third detecting portion 193 of the dog (step S5), it is determined that the carriage 3 has reached the upper end position, and the carriage 3 is forcibly decelerated and stopped (step S6). ).
[0027]
As described above, in the present embodiment, it is determined whether or not the speed of the carriage 3 is equal to or higher than a predetermined value when the first detection unit 191 and the second detection unit 192 of the dog 19 are detected. Since the carriage 3 is moved at the same speed, the carriage 3 can be moved to the terminal position in the shortest time without performing unnecessary deceleration as in the related art. As a result, the cycle time can be reduced.
[0028]
Note that the second detection unit 192 of the dog 19 may be omitted, and the determination as to whether or not the speed of the carriage 3 is equal to or higher than a predetermined value may be performed only at the position A. However, the speed can be more finely controlled by performing the check at the two positions of the position A and the position B as described above.
[0029]
On the other hand, when the speed of the carriage 3 is equal to or higher than the predetermined value at the time when the first detection unit 191 and the second detection unit 192 are detected, the emergency stop is performed. It can be stopped at the end position. For this reason, the length of the dog 19 can be reduced to about half the conventional length.
[0030]
Although the upper dog 19 has been described above as an example, the same applies to the lower dog 20.
[0031]
FIGS. 5 and 6 show another embodiment of the present invention, in which the traveling vehicle 15 of the crane 1 is a moving body. FIG. 5 is a schematic plan view of the traveling vehicle 15 as viewed from above, and reference numerals 30, 31, 32a, and 32b denote sensors. The sensors 30 and 31 are ordinary photoelectric sensors, and the sensors 32a and 32b are the two-axis photoelectric sensors shown in FIG.
[0032]
FIG. 6 is a diagram showing the arrangement of dogs. Dogs are arranged in three rows, dogs 33 and 34 are dogs on the start end, and dogs 35 and 36 are dogs on the end side. Dog 33 is detected by sensor 30, dogs 34 and 35 are detected by sensors 32a and 32b, and dog 36 is detected by sensor 31.
[0033]
The dogs 33 and 36 correspond to the first detection unit 191 in FIG. 3. When the position A corresponding to FIG. 3 is detected by the sensors 30 and 31, the speed of the traveling vehicle 15 becomes equal to or higher than the predetermined value V ₁ . It is determined whether or not there is. If the speed is equal to or more than a predetermined value, it is determined that the speed is abnormal, and an emergency stop is performed.
[0034]
The dogs 34 and 35 correspond to the second detection unit 191 and the third detection unit 193 in FIG. 3, and when the B position corresponding to FIG. 3 is detected by the sensors 32a and 32b, the speed of the traveling vehicle 15 Is determined to be greater than or equal to a predetermined value V ₂ (V ₂ <V ₁ ). If the value is greater than or equal to the predetermined value, it is determined that the speed is abnormal, and an emergency stop is performed. Move. When the position C corresponding to FIG. 3 is detected by the sensors 32a and 32b, it is determined that the traveling vehicle 15 has reached the end position, and the vehicle is forcibly decelerated and stopped.
[0035]
In this manner, also when the present invention is applied to the traveling vehicle 15, the cycle time can be reduced and the dog length can be shortened by the same principle as that of the carriage 3. The reason why the dogs 33 and 34 and the dogs 35 and 36 are separated in FIG. 6 is that the dog 33 and the dog 36 determine whether the traveling vehicle 15 is moving forward or backward.
[0036]
The present invention is not limited to only the above-described embodiment, and may adopt various other forms. For example, in the embodiment of FIG. 3, the speed of the moving body is determined in two stages of the position A and the position B. However, the speed of the moving body is divided into three or more stages by changing the shape of the dog. May be determined.
[0037]
In the above-described embodiment, the two-axis photoelectric sensor is used as the sensor, which has an advantage that the configuration is simplified. However, the same function is realized by using two one-axis photoelectric sensors instead. It is also possible.
[0038]
【The invention's effect】
According to the present invention, it is possible to avoid unnecessary deceleration by determining the speed of the moving body at the time when the sensor detects the dog, thereby improving cycle time and shortening the dog length. Becomes possible.
[0039]
Further, by performing the speed determination in a plurality of stages, the speed can be more finely controlled.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic structure of a stacker crane according to an embodiment of the present invention.
FIG. 2 is a perspective view of a two-optical axis photoelectric sensor.
FIG. 3 is a diagram illustrating an operation of speed control.
FIG. 4 is a flowchart showing an operation of speed control.
FIG. 5 is a schematic plan view of a traveling vehicle showing another embodiment of the present invention.
FIG. 6 is a layout view of a dog showing another embodiment of the present invention.
FIG. 7 is a perspective view showing a schematic structure of a conventional stacker crane.
[Explanation of symbols]
1 Stacker crane 3 Carriage 15 Running vehicle 18 Sensor 19 Forced deceleration dog 20 Forced deceleration dog 191 First detector 192 Second detector 193 Third detector X ₁ optical axis X ₂ optical axis

Claims (4)

A sensor attached to the moving body, and a forced deceleration dog detected by the sensor, the forced deceleration dog has at least two detection units on the tip side and the end side, and the sensor When the detection unit on the side is detected, it is determined whether or not the speed of the moving body is equal to or more than a predetermined value, and when the speed is equal to or more than the predetermined value, forced deceleration for the emergency stop is performed on the moving body. When the speed is less than a predetermined value, the moving body is moved at the same speed, and when the sensor detects the detection unit on the terminal side, control is performed to forcibly stop the moving body. Speed control device for moving objects in cranes. The stacker crane according to claim 1, wherein the sensor is a photoelectric sensor having two optical axes, and identifies each detection unit of the forced deceleration dog from a combination pattern of shielding and transmission of each optical axis. Speed control device for moving objects. 3. The speed control device for a moving body in a stacker crane according to claim 1, wherein the moving body is a carriage that moves up and down in a vertical direction. The speed control device for a moving body in a stacker crane according to claim 1, wherein the moving body is a traveling vehicle that travels in a horizontal direction.

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