JPH07232806A - Stacker crane control device - Google Patents

Abstract

PURPOSE:To shorten operating cycle time by moving forward a fork before a stacker crane stops traveling. CONSTITUTION:When a clearance C between rack supports 14 and 14 which are projected into a space between columns 13 and 13 and on which an article W is loaded and a fork 15 is longer than a creep distance when a a stacker crane is stopped, the stacker crane is unloaded, and a lifting table stops lifting earlier, the fork 15 does not interfere with the rack support 14, etc. Thus, even if the stacker crane is just stopping to travel, the fork starts to move forward when its speed is reduced to a creep speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stacker crane control device for controlling a stacker crane provided in an automatic warehouse, and more particularly to a stacker crane control device capable of shortening operation cycle time.

[0002]

2. Description of the Related Art In a factory, a warehouse, etc., in order to temporarily store articles, a rack of a plurality of shelves and a front side of the front of the rack of racks are run to elevate and lower the elevator to prepare for the elevator. An automatic warehouse including a stacker crane that transfers articles to and from a shelf by a fork is used. The operation of the stacker crane is controlled by the control device mounted on the stacker crane. Each operation of traveling, lifting, and fork movement is controlled by so-called trapezoidal control. FIG. 3 shows the relationship between the speed and time during the traveling of the stacker crane. After starting, the stacker crane accelerates to a high speed (operating speed) V _H ,
The vehicle decelerates to a low speed V _L before the target point, further decelerates to an ultra-low creep speed V _C , enters a stop preparation state, travels a creep distance S _C , and stops at the target point.

[0003]

The advancement of the fork for delivering the article by the fork has been started after the traveling and the elevating / lowering are stopped. In the case of actual load, the mast of the crane has been shaking for a while after the stacker crane has stopped moving, so to prevent the load from collapsing, wait for the time until the shaking stops and advance the fork. Let
In the case of an empty load, the mast has stopped shaking by the time the fork has advanced, so the fork is advanced immediately after traveling stops, but in any case, traveling / elevation- (waiting for shaking stop) -fork advance -The processes of scooping / delivering-fork retracting-traveling / elevating were processed in sequence, and there was no duplicate processing.

Therefore, an object of the present invention is to provide a stacker crane control device capable of shortening the operation cycle time by causing the traveling and the fork advance to overlap partially.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 is a stacker crane control device for controlling a stacker crane having a lift table on which a fork is mounted. The stacker crane control device is provided with a means for determining whether or not the object interferes with the stacker crane, and even before the stacker crane is stopped, the fork is advanced when the determination means determines that the object does not interfere with another object. Configured.

According to a second aspect of the present invention, the other object is a rack of a rack device, and the interference determination means of the fork is in a stop preparation state in which the stacker crane travels at a speed lower than the operating speed. The stacker crane control device according to claim 1 is configured to judge that the distance from the current position of the crane to the travel stop position is sometimes shorter than the clearance between the shelf receiver and the fork of the target shelf.

According to a third aspect of the present invention, the lift table is empty, and the lift table has already reached the target shelf position when the stacker crane shifts to the stop preparation state. For example, the stacker crane control device according to claim 2 is configured to advance the fork.

[0008]

Since the present invention has the above-mentioned structure, it has the following effects.

In the stacker crane control device according to the first aspect of the present invention, the determining means determines whether or not the object interferes with other objects when the fork advances, and the fork is advanced before the stacker crane is stopped. If it is determined that does not interfere with other objects, the fork operation is controlled so that the fork advances even if the stacker crane is still moving.

In the stacker crane control device according to the second aspect of the present invention, the interference determining means determines whether the fork interferes with the rack of the rack device, and the stacker crane travels at a speed slower than the operating speed. Judges if the distance from the current position of the crane to the travel stop position is shorter than the clearance between the target shelf shelf and the fork when in the stop preparation state, and if it is short, advance the fork even before the crane is stopped. Let At this time, since the fork advances into the clearance, it does not interfere with the shelf receiver.

In the stacker crane control device according to the third aspect of the present invention, the interference determination means is such that the lift table is empty and the lift table is already the target when the stacker crane shifts to the stop preparation state. If the shelf position of is reached, advance the fork. If the load is not empty, the load may collapse if the fork on which the load is placed is moved before stopping traveling. Further, if the ascending / descending reaches the target shelf position position and is stopped first, the forks do not interfere with the shelf supports of the rack device, the pillars, and the articles stored in the rack device.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the drawings will be described below.

FIG. 1 is a block diagram showing the configuration of an embodiment of a stacker crane control device according to the present invention.

In the figure, the control device 1 controls the outputs of the inverters 2 and 3 to drive a traveling motor 4 for driving the traveling carriage of the stacker crane, an elevating motor 5 for raising and lowering the lifting platform, and a fork. The operation of the driven fork motor 6 is controlled. The inverter 3 is also used as an inverter, and outputs to either the lift motor 5 or the fork motor 6 by a switching device (not shown).
Therefore, traveling and lifting, and traveling and fork operation can be performed at the same time, and lifting and fork operation cannot be performed at the same time.

The rotation of the traveling motor 4 is detected by the encoder 7 and fed back, so that the control device 1 can know the traveling position. Further, a photoelectric sensor 8 for correcting the traveling position by detecting the shield plate arranged at a fixed position along the traveling route is connected.

The movement pattern creating section 9 creates a speed pattern as shown in FIG. 3, which is a change in speed with time of traveling / up and down according to a work instruction for loading and unloading. Acceleration / deceleration required to create a speed pattern, high speed (operating speed) V _H ,
Data such as the low speed V _L creep speed V _C and the creep distance S _C are stored in the movement data 10.

Further, the shelf data 11 stores data for each shelf in the rack series, and also stores the size of the clearance for each shelf. Based on the size of the clearance, the fork control unit 12 Make a fork advance before the stop. Two types of speed patterns for moving the fork are prepared in advance, one for an actual load and one for an empty load.
The clearance mentioned here is the clearance C between the forks 15 and the shelf supports 14 and 14 which project between the columns 13 of the racks as shown in FIG. 4 and on which the article W is placed. .

Next, with reference to FIG. 2, the process steps of this embodiment will be described.

When a work instruction is issued, the movement pattern creating section 9 takes out various data from the movement data 10 and creates a traveling / elevating pattern (step 1). The work instruction is composed of a start point and an end point of the work. If the start point is a station, it is a warehousing work, and if it is a shelf, it is a warehousing work. The control device 1 drives the traveling motor 4 and the elevating motor 5 to move the elevating table from the current position to the station which is the starting point or the front surface of the designated shelf, performs the transfer work, and is the station which is the ending point or The lifting table is moved to the front of the designated shelf and the transfer work is performed to complete the work.

When the movement pattern is created, it is judged whether or not the stacker crane is empty (step 2). The stacker crane is empty when the stacker crane moves from the current position to the starting shelf in the shipping operation. In the case of other actual loads, the pattern for actual loads is applied (step 3), and the fork advance is started after waiting for the mast to stop shaking after the traveling / elevation stop.

When transferring to and from a station, communication is usually required for interlocking between the stacker crane control device and the station after the traveling is stopped, so that the fork can advance before the traveling is stopped. It is difficult to use a general stacker crane.

Next, the traveling pattern and the ascending / descending pattern are compared to determine whether the ascending / descending stop is before the stop preparation transition time t _f (step 4). As shown in FIG. 3, the traveling speed of the stacker crane is reduced to the creep speed V _c when approaching the target position, and the stop preparation state is entered. When the transition to stop ready to stop preparing the transition time t _f. Creep rate V _c is a very low speed that normally 3 to 5 m / min. If towards the elevator stops after the stop preparatory transitional t _f, in the present embodiment without the fork advance it can determine whether or not, is advanced a fork unloaded pattern after lifting stopped (Step 5) .

In order to advance the fork before stopping the raising and lowering, it is necessary to know the vertical clearance of the shelf directly below the target shelf, and whether the clearance is stored or not is determined. Since the data processing becomes complicated because it changes depending on the height of the loaded load, in this embodiment, the fork advance is not performed before the lifting / lowering is stopped. Further, in this embodiment, since the single inverter 3 drives the lifting motor 5 and the fork motor 6, it is impossible to advance the fork during lifting.

Next, the data of the target shelf is read from the shelf data 11, and it is judged whether or not the size of the clearance C is larger than the creep distance S _c (step 6).
If the clearance C is larger, the stop preparation transition time t _f
The fork is advanced in the empty loading pattern (step 7).

If the clearance C is larger than the creep distance S _c , the fork 15 moves at the stop preparation transition time t _f .
The fork 15 is the clearance C
It extends through and does not collide with the shelf bracket 14. Further, after the time t _f at the time of shift to stop preparation, if the distance traveled before stopping becomes shorter than the clearance C, the fork 15 can be advanced, but control becomes complicated. Therefore, in this embodiment, shift to stop preparation is performed. It was decided to make a judgment only at time t _f .

If the clearance C is smaller than the creep distance S _c , the fork is operated in the empty pattern after the lifting / moving / stopping (step 5).

As described above, according to the stacker crane control device according to the present embodiment, when there is no possibility of interfering with the shelf support, articles, etc. even if the fork is advanced, the fork advances before the traveling is stopped. Since it can start, the operation cycle time of the stacker crane can be shortened and the capacity of the automated warehouse can be improved.

The embodiment of the present invention has been described above.
It is needless to say that the present invention is not limited to the above-mentioned embodiments and can be appropriately modified within the scope of the gist of the present invention.

[0029]

As described above, according to the stacker crane control device of the first aspect of the present invention, even if the fork is advanced, there is a possibility of interfering with other objects such as shelves, columns and articles. When there is no stacker crane, the fork advance can be started before the stacker crane is stopped, so that the operation cycle time of the stacker crane can be shortened and the capacity of the automated warehouse can be improved.

According to the stacker crane control device of the second aspect of the present invention, in the stop preparation state, the distance from the current position of the crane to the traveling stop position is the clearance between the shelf receiver of the target shelf and the fork. If it is shorter than this, the operation cycle time can be improved by allowing the fork to advance before the crane stops.

According to the stacker crane control device of the third aspect of the present invention, if the lift table is empty and the lift table is stopped first, the fork can be advanced during the stop preparation state. By making it possible, it is possible to improve the operation cycle time while preventing the collapse of the load and the interference between the fork and other articles.

[Brief description of drawings]

FIG. 1 is a block diagram showing a structure of an embodiment of a stacker crane control device according to the present invention.

FIG. 2 is a flowchart showing a process of processing of the embodiment of FIG.

FIG. 3 is a diagram showing a speed-time relationship which is an example of a traveling speed pattern in the embodiment of FIG.

FIG. 4 is a front view showing a part of a stacker crane to which the embodiment of FIG. 1 is applied.

[Explanation of symbols]

 13, 13 Pillar 14, 14 Shelf receiver 15 Fork W Article C Clearance

Claims (3)

[Claims] 1. A stacker crane control device for controlling a stacker crane having a lifting platform having a fork mounted thereon, further comprising means for judging whether or not it interferes with another object when the fork advances, and before the stacker crane is stopped. A stacker crane control device for advancing a fork when it is determined by the determination means that it does not interfere with other objects even if there is. 2. The other object is a rack of a rack device,
Further, the fork interference determination means, when the stacker crane is in a stop preparation state in which the stacker crane travels at a speed slower than the operating speed, the distance from the current position of the crane to the travel stop position is determined by the rack shelf of the target shelf and the fork. The stacker crane control device according to claim 1, wherein the stacker crane control device determines that the clearance is shorter than the clearance. 3. The lift table is empty and when the stacker crane shifts to the stop preparation state,
The stacker crane control device according to claim 2, wherein the fork is advanced when the lifting platform has already reached a target shelf position.