JPH02265804A - Method of controlling stacker crane - Google Patents

Abstract

PURPOSE:To prevent destruction of a stack and enhance the efficiency of conveyance in an automatic warehouse by providing such an arrangement that when data of a desired position and articles to be handled is delivered to a crane from a ground controller, an acceleration pattern and a deceleration pattern are set on the crane side, and accordingly, the crane is moved while detecting the position of the crane itself. CONSTITUTION:When a CPU for controlling an automatic warehouse delivers data of a working location and articles to be handled, a ground controller 12 for a crane transmits this data to an on-board controller 16 on the crane. The on-board controller 16 delivers a characteristic parameter and the like concerning an optimum speed to an optimum speed pattern computing device 28 in accordance with the delivered data. The optimum speed pattern computing device 28 computes an optimum speed pattern which is then delivered to the controller 16. The controller 16 operates a drive device 18 in accordance with this optimum speed pattern so as to move and handle the articles. With this arrangement, it is possible to prevent the destruction of a stack and to enhance the efficiency of conveyance.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method of controlling a stacker crane used in an automated warehouse, and it is possible to prevent inconveniences such as cargo shifting by controlling the stacker crane with a speed pattern suitable for the material being handled. This makes it possible to transport the handled items with high efficiency without causing any problems.

[Conventional technology]

A stacker crane used in an automated warehouse or the like travels along shelves, moves up and down, and extends a fork at a designated shelf address to load and unload cargo.

FIG. 3 shows a control system of a conventional stacker crane. Ground automatic warehouse control computer (
An instruction for work logging (target shelf address) is given from the rcpu (hereinafter referred to as rcpu) 10, and transmitted to the crane 14 via the crane ground controller 12 by wireless or the like. The crane 14 receives this and activates it according to the speed pattern formed by the crane on-board controller 16.
A stop instruction is sent to the drive control panel 18, and the drive motor 20,
The lifting motor 22 and the fork drive motor 24 are respectively driven. At this time, the position in the running direction and the position in the lifting direction are
Sensors 26 such as photocouplers detect markers such as plates installed for each shelf address along the traveling route and the lifting post, and count the detected markers, which are given from the crane on-board codon roller 16. As a result of driving according to the speed pattern, it stops when it reaches the target shelf address, extends the fork, and carries in and out the items to be handled.

FIG. 4 shows an example of speed patterns for running and lifting. It accelerates at a predetermined acceleration from speed 0, shifts to steady running when it reaches speed v1, and decelerates at a predetermined acceleration when a shelf a predetermined number of times before the target shelf address is detected. Then, when the speed drops to v2, it runs steadily to prevent drifting, and after a predetermined time, it further decelerates, and when it drops to speed v3, it runs steady, and when it reaches the target shelf address, it applies the brakes and stops.

Conventionally, this speed pattern was fixed.

[Problem to be solved by the invention]

When operating a stacker crane, it is necessary to operate the stacker crane at a speed pattern that prevents the loaded objects from being dislodged. The ease with which a load collapses varies depending on the characteristics of the object being handled (shape, weight, coefficient of friction, material, etc.) and loading conditions (number of loading stages, etc.). For example, even when the item to be handled is a cardboard package, the ease with which the item collapses varies depending on its shape, coefficient of friction, number of loading stages, etc. Furthermore, when handling precision machinery, an upper limit on acceleration may be set.

In the past, a fixed speed pattern was used, so all handled items could be handled without shifting.
In addition, if acceleration is limited, a speed pattern must be determined to satisfy the limitation, and acceleration and steady speed are limited to low values. Therefore, this speed pattern is used even when transporting objects that are difficult to dislodge or when moving empty, which has the drawback of taking too much time and reducing efficiency.

This invention solves the drawbacks in the conventional techniques, and
The object of the present invention is to provide a method for controlling a stacker crane that allows objects to be transported with high efficiency without causing the cargo to collapse.

[Means to solve the problem]

This invention transmits information on the target position and information on the object to be handled from a controller on the ground side, receives this on the crane side, sets an acceleration pattern and a deceleration pattern according to the information on the object to be handled, and sets an acceleration pattern and a deceleration pattern according to the information on the object to be handled. The device moves in the direction of the target position while detecting its own position.

[For production]

According to this invention, when the controller on the ground side transmits information regarding the object to be handled (physical characteristic parameters of the object, loading status, etc.), the crane side receives this information and prevents the load from shifting or the upper limit of acceleration. A speed pattern is set that does not exceed , and the crane is driven according to this pattern.

Therefore, ffi!
For items to be handled that are limited in f, we prevent load collapse and excessive acceleration by keeping the acceleration and steady speed low, and for items that are difficult to collapse or move empty, we increase the acceleration and steady speed to achieve high efficiency. can be driven with.

Note that the optimum speed pattern is determined in advance on the crane side according to the various types of objects to be handled and the loading conditions, etc. through experiments, for example, and one of the speed patterns is determined in advance according to the information transmitted from the ground to the object to be handled. You can choose a pattern.

Alternatively, a basic speed pattern may be determined, and this speed pattern may be modified and used in accordance with information regarding the object to be handled that is transmitted from the ground. Further, it is also possible to create a speed pattern by calculation according to information regarding the item.

Furthermore, it is also possible to provide a learning function so that the speed pattern can be corrected or changed if a load collapses during operation. It is also possible to detect the swaying state of the load during transportation and control the speed using fuzzy control.

〔Example〕

An embodiment of this invention will be described below.

FIG. 1 shows an embodiment of a control system for a stacker crane to which the present invention is applied. The automatic warehouse control CPtJ10 on the ground provides information on the work location (target shelf address) and the items to be handled, and transmits the information via the crane ground controller 12 to the crane 14 by wireless or the like. The crane 14 receives this, calculates or selects the optimum speed pattern for the object to be handled using the optimum speed pattern calculating device 28, and sends start and stop instructions to the drive control panel 18 from the crane on-board controller 16 according to the speed pattern. The drive motor 20, the lift motor 22, and the fork drive motor 24 are respectively driven.

At this time, the position in the running direction and the position in the lifting direction are determined by detecting markers such as plates installed for each shelf address along the running path and the lifting post with a sensor 26 such as a photocoupler, and counting them. Detected. As a result of driving in accordance with the speed pattern given from the i-overspeed pattern calculating device 28, when the target shelf address is reached, the machine stops, and the fork is extended to carry in and take out the items to be handled.

Examples of speed patterns for running and climbing given by the optimum speed pattern calculating device 28 are shown in FIG. The vehicle starts traveling, and when a shelf a predetermined number of times before the target shelf address is detected, the vehicle decelerates at a predetermined acceleration.

When the speed drops to V2, the vehicle starts to run steadily to prevent drifting, and after a predetermined period of time, it further decelerates to speed V3.
When the vehicle reaches the target shelf address, it will continue to run steadily, and when it reaches the target shelf address, it will apply the brakes and stop.

Speed pattern (2) has high acceleration and steady speed, and is used when handling objects that are unlikely to be dislocated or when moving empty. The speed pattern @ has medium acceleration and steady speed, and is used when transporting ordinary objects. Speed pattern (3) has low acceleration and steady speed, and is used when transporting objects that tend to collapse or whose acceleration is limited, such as precision machinery.

The speed pattern can be determined by examining the state of load shedding through experiments or the like for various types of objects to be handled. In that case, by simply transmitting the name of the object to be handled as information about the object from the ground side, the crane can select and use the corresponding speed pattern.

Furthermore, the speed pattern can also be corrected by transmitting information such as the number of items to be handled.

Further, the size and weight of the object, the original oscillation coefficient, the number of loading stages, etc. can be sent from the ground side as information regarding the object to be handled, and the optimum speed pattern calculation device 28 can set the speed pattern by calculation.

Further, the optimum speed pattern calculating device 28 can be configured with a single board computer having a learning function or a dedicated fuzzy controller, and the speed pattern can be determined by detecting the state of load collapse, the swaying state of the object to be handled, and the like.

Note that the drive of the fork can also be controlled by selecting or calculating a speed pattern in the same manner.

〔Effect of the invention〕

As explained above, according to the present invention, the controller on the ground side transmits information regarding the object to be handled, and the crane side receives this information to create a speed pattern that does not cause the load to collapse or exceed the upper limit of acceleration. Since the crane can be set and driven according to this, it is possible to drive the crane according to the speed pattern depending on the object to be handled, and for objects to be handled that are likely to collapse or whose acceleration is restricted, the acceleration or steady speed can be changed. By keeping the load low, it is possible to prevent the load from collapsing and excessive acceleration, and when handling items that are difficult to collapse or moving empty, the acceleration and steady speed can be increased to enable highly efficient operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a control system of a stacker crane to which the present invention is applied. FIG. 2 is a diagram showing an example of an optimal speed pattern set by the optimal speed pattern calculating device 28 of FIG. 1. FIG. 3 is a block diagram showing a control system of a conventional stacker crane. FIG. 4 is a diagram showing an example of a speed pattern used in the control system of FIG. 3. DESCRIPTION OF SYMBOLS 10... CPU for automatic warehouse control, 12... Crane ground controller, 14... Crane, 16... Crane on-board controller, 28... Optimum speed pattern calculation device.

Claims (1)

[Claims] The controller on the ground side transmits information on the target position and information on the object to be handled, the crane side receives this, sets an acceleration pattern and deceleration pattern according to the information on the object to be handled, and adjusts its own position according to this pattern. A method for controlling a stacker crane, wherein the stacker crane is moved in the direction of the target position while detecting the target position.