JP4458164B2 - Automatic warehouse - Google Patents

Description

  The present invention relates to an automatic warehouse, and more particularly to an automatic warehouse including a shelf for storing articles and a transfer device for transferring articles to the shelves.

Conventionally, there is an automatic warehouse equipped with a stacker crane (see, for example, Patent Document 1). In this automatic warehouse, a rack having a large number of article storage shelves for storing articles is provided, and a station as an article transfer location for transferring articles from the rack to a stacker crane is provided. The stacker crane travels in front of the rack, picks up incoming goods from the station and transports it to the rack, and takes out outgoing goods from the rack and transports it to the station.
JP 2001-341809 A

  By the way, when taking out an article from a rack in a conventional automatic warehouse, a movable part such as a slide fork moves to a take-out position in front of the shelf, and the bottom part of the article is supported by the movable part by expansion and contraction of the movable part and raising and lowering of the lifting platform. The The take-out position and the shelf position are set so that there is no collision between the article supported by the movable part and the shelf in the article take-out operation.

  However, when an unexpected event such as a change in shelf position due to secular change or a change in floor inclination due to ground subsidence occurs, a collision between the article and the shelf occurs. In such a case, since the stacker crane does not know that the shelf collides with the article and raises the lifting platform after the collision and continues the article taking-out operation, the rack and the article are damaged.

  Then, an object of this invention is to provide the automatic warehouse which can prevent the collision with a shelf and articles | goods in view of this problem.

  In order to achieve the above object, an automatic warehouse according to the present invention includes a rack having a shelf for storing articles, a transfer unit for putting articles in and out of the shelf, and a control unit for controlling the operation of the transfer unit. The transfer unit includes: a movable part on which the article is placed; and a movable part that enters and exits the shelf; and an insertion part and a shelf of the movable part that are provided in an insertion part that is inserted into the shelf of the movable part. A distance sensor that measures the distance in the vertical direction, and the control unit limits the movement of the transfer unit when the distance measured by the distance sensor is smaller than a threshold value.

  Here, the distance sensor may be an ultrasonic sensor that transmits an ultrasonic wave to the shelf and receives an ultrasonic wave reflected from the shelf. The rack further includes a reflection plate provided on the shelf that reflects light from outside the shelf, and the distance sensor irradiates the reflection plate with light and receives light from the reflection plate. A photoelectric sensor may be used.

  This also restricts the movement of the transfer unit when the distance between the shelf and the movable unit is smaller than the threshold, and can avoid collision between the article on the movable unit and the shelf. Therefore, even when the shelf position changes due to an unexpected event such as secular change, the collision between the article and the shelf can be avoided.

  Here, the distance sensor may be provided at a distal end portion and a proximal end portion in the insertion direction of the movable portion in the insertion direction to the shelf.

  As a result, even if the tip of the movable part bends due to the load of the article and the distance sensor between the movable part and the shelf cannot be accurately measured by the distance sensor at the tip of the movable part, the distance sensor at the base of the movable part that is less affected by the deflection. The distance between the movable part and the shelf can be accurately measured. In addition, even if the transfer unit has a function of correcting the deflection of the movable unit and the distance between the movable unit and the shelf cannot be accurately measured by the distance sensor at the distal end of the movable unit because the distal end of the movable unit is lifted, The distance between the movable part and the shelf can be accurately measured by the end distance sensor. As a result, the collision between the article and the shelf can be avoided with high accuracy.

  The distance sensor may be provided on an upper surface on which the article is placed in an insertion portion of the movable part. Further, the control unit may stop the raising operation of the movable unit when the distance measured by the distance sensor is smaller than a threshold value.

  Thereby, when the distance of a shelf and a movable part is smaller than a threshold value, the raise operation | movement of a movable part stops. Therefore, even when the shelf position changes due to an unexpected event such as secular change, the collision between the article and the shelf can be reliably avoided.

  ADVANTAGE OF THE INVENTION According to this invention, the automatic warehouse which can prevent the collision with a shelf and articles | goods is realizable. Accordingly, it is possible to prevent the article and the rack from being damaged due to the collision.

  Hereinafter, an automatic warehouse according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of an automatic warehouse in the present embodiment.

  This automatic warehouse is composed of a stacker crane 1, a rack 2 provided along the path of the stacker crane 1, and a station 3 on which articles 8 are placed at the time of loading and unloading.

  The stacker crane 1 is an example of a transfer unit according to the present invention, and puts in and out the articles 8 to be stored in and out of the rack 2. Specifically, the stacker crane 1 has a function of taking the article 8 to be received from the station 3 and transporting it to the rack 2 rack, and taking out the article 8 from the rack 2 to transport it to the station 3. Have.

  The rack 2 is provided with a plurality of shelves for storing the articles 8 vertically and horizontally. Note that the racks 2 may be provided on both sides of the path of the stacker crane 1.

  FIG. 2 is a diagram schematically illustrating an example of the configuration of the stacker crane 1. FIG. 2 corresponds to the left side view of the automatic warehouse of FIG. Here, it is assumed that racks 2 are provided on both sides of the path of the stacker crane 1. For convenience, the rack on the right side of the drawing is called a right rack 2R, and the rack on the left side is called a left rack 2L.

  The stacker crane 1 includes a lower carriage 11, an upper carriage 12, a mast 13, a lifting platform 16, and a control device 23.

  The lower carriage 11 includes a wheel 14 for traveling on the rail 4 laid on the floor and a traveling motor 15 for driving the wheel 14, and moves on the rail 4 in the horizontal direction.

  On the mast 13, a lifting platform 16 is mounted so as to be movable up and down, and a winch motor 17 is mounted. The elevator 16 is suspended by a wire rope 19 guided by a sheave 18 and moves up and down along the mast 13 in accordance with the operation of the winch motor 17.

  The elevator 16 is provided with a slide fork 20. The slide fork 20 is an example of the movable part of the present invention, and the article 8 is placed on and out of the shelf. The slide fork 20 includes a plurality of plates 21 connected to each other so as to be movable back and a transfer motor 22 for moving the plates 21 back and forth from the lifting platform 16. The uppermost plate 21 functions as a mounting table on which the article 8 is mounted. The article 8 is assumed to be an article in which the slide fork 20 can be inserted into the bottom, that is, an article such as a box on a pallet or a basket-type pallet.

  The control device 23 controls operations of the traveling motor 15, the winch motor 17, and the transfer motor 22.

  The stacker crane 1 travels on the rail 4 to a desired shelf of the rack 2 or the station 3 under the control of the control device 23, moves the elevator 16 up and down, and moves the slide fork 20 in and out to move the elevator 16 The article 8 is transferred between the rack 2 and the station 3.

  FIG. 3 is a diagram showing the configuration of the slide fork 20 in detail.

  A mechanism for preventing a collision with the shelf is provided at the tip of the slide fork 20. Specifically, the slide fork 20 is a distance for measuring the vertical distance between the slide fork 20 (the insertion portion (part A in FIG. 3) inserted into the shelf in the plate 21 on the top layer of the slide fork 20) and the shelf. A sensor 29 is provided.

  The distance sensor 29 is provided on the upper surface on which the article 8 at the distal end portion in the insertion direction of the shelf (direction B in FIG. 3) and the proximal end portion in the insertion direction is placed at the insertion portion of the plate 21 at the uppermost layer of the slide fork 20. The distance sensor 29 is an ultrasonic sensor that transmits ultrasonic waves to the shelf and receives ultrasonic waves reflected from the shelf, for example.

  FIG. 4 is a block diagram showing a functional configuration of the automatic warehouse according to the present embodiment.

  The automatic warehouse includes a mechanism unit 30, a control unit 31, a display unit 32, an input unit 33, a communication I / F unit 34, a collision prevention unit 35, a threshold value determination unit 36, and a storage unit 39. The control unit 31 and the collision prevention unit 35 are examples of the control unit of the present invention.

  The mechanism unit 30 is a set of mechanism parts such as the stacker crane 1.

  The control part 31 controls the mechanism part 30 according to a conveyance command, a stop command, etc.

  The display unit 32 is a CRT (Cathode-Ray Tube), LCD (Liquid Crystal Display), etc., and the input unit 33 is a keyboard, a mouse, etc., which are used for dialogue between the automatic warehouse and the operator. Used.

  The communication I / F unit 34 is used for communication with the stacker crane 1.

  The collision prevention unit 35 determines whether or not the distance between the slide fork 20 and the shelf is smaller than the threshold and the possibility that the item 8 and the shelf collide is high when the article 8 is taken out from the shelf. If the collision prevention unit 35 determines that there is a high possibility of a collision, the collision prevention unit 35 generates a command to limit the movement of the slide fork 20. Specifically, the collision prevention unit 35 generates a stop command for controlling the stacker crane 1 so as to slow the rising speed of the lifting platform 16 and stop the lifting operation.

  The threshold value determination unit 36 determines a threshold value used for collision determination by the collision prevention unit 35 so that the article 8 and the shelf do not collide when the article 8 is taken out, and stores the threshold value in the storage unit 39.

  The storage unit 39 is a hard disk, a memory, or the like, and holds a threshold value of the distance between the slide fork 20 and the shelf determined by the threshold value determination unit 36.

  FIG. 5 is a flowchart for explaining the conveying operation of the article 8 in the automatic warehouse having the above configuration.

  First, the threshold determination unit 36 determines a threshold used for collision determination by the collision prevention unit 35 (step S31). Specifically, the threshold value determination unit 36 receives information on the height of the article 8 stored on the shelf via the input unit 33 and stores the value obtained by adding a predetermined value to the height of the article 8 as a threshold value. Stored in the unit 39.

  A predetermined value added to the threshold value when determining the threshold value is a distance between the shelf and the article 8 in taking out the article 8 from the shelf, that is, a clearance. Therefore, when it is necessary to ensure further safety, that is, when it is desired to reliably prevent the article 8 and the shelf from colliding by increasing the clearance, the predetermined value added to the height of the article 8 is a threshold value. Largely set by the determination unit 36. For example, a plurality of modes corresponding to the height of safety that needs to be ensured, such as a normal mode and a safety mode, are provided, and in the safety mode, a value larger than the normal mode is set to be added to the height of the article 8, This can be realized by receiving a mode selection by the user via the input unit 33 or the like.

  Next, the control unit 31 receives a conveyance command via the input unit 33 and the like, and controls the mechanism unit 30 to take out the article 8 from the conveyance source shelf indicated in the conveyance command (step S32). Specifically, the control unit 31 controls the winch motor 17 so that the lifting platform 16 moves to the take-out position in front of the shelf of the conveyance source indicated by the conveyance command. Thereafter, the transfer motor 22 is controlled so that the uppermost plate 21 of the elevator 16 enters the shelf, and the winch motor 17 is controlled so that the elevator 16 rises in the entry state. As a result, the article 8 placed on the shelf is transferred onto the uppermost plate 21.

  Next, the collision prevention unit 35 determines whether or not there is a high possibility that the article 8 and the shelf collide, that is, whether or not the distance between the shelf and the slide fork 20 exceeds the threshold and is smaller than the threshold (step). S33). Specifically, the collision prevention unit 35 receives distance information regarding the distance between the slide forks 20 and the shelves from all the distance sensors 29, and any one of the distances between the slide forks 20 and the shelves indicated in the distance information is stored in the storage unit. It is determined whether it is smaller than the threshold value stored in 39.

  Next, when it is determined that there is a high possibility that the article 8 and the shelf will collide (Yes in step S33), the collision prevention unit 35 generates a stop command (step S34).

  Next, the control unit 31 receives a stop command from the collision prevention unit 35, and controls the mechanism unit 30 so that the stop command is executed (step S35). Specifically, the control unit 31 receives the stop command, controls the winch motor 17 so as to slow down the ascending speed of the lifting platform 16 and stop the ascending operation.

  Next, when it is determined that the possibility that the article 8 and the shelf collide is low, that is, when it is determined that the value is equal to or higher than the threshold (No in Step S33) or when a stop command is executed, the control unit 31 Then, the mechanism unit 30 is controlled so that the article 8 transferred onto the uppermost plate 21 is conveyed to the station 3 (step S36). Specifically, the control unit 31 controls the winch motor 17 and the traveling motor 15 so that the elevator 16 is moved to the station 3 after controlling the transfer motor 22 so that the plate 21 is pulled into the elevator 16. .

  As described above, according to the automatic warehouse of the present embodiment, in the operation of taking out the article 8 from the shelf, the distance between the slide fork 20 and the shelf is measured by the distance sensor 29. The rise of the base 16 is stopped. Therefore, even when the shelf position changes due to an unexpected event such as secular change, the collision between the article and the shelf can be avoided.

  Further, according to the automatic warehouse of the present embodiment, the distance sensor 29 is provided not only at the distal end portion in the insertion direction of the slide fork 20 in the shelf but also at the proximal end portion in the insertion direction, and the distal end portion in the insertion direction and the proximal end in the insertion direction. The movement of the slide fork 20 is restricted when any of the distances obtained by the distance sensor 29 is smaller than the threshold value. Therefore, even when the tip of the slide fork 20 is deflected by the load of the article 8 and the distance between the shelf and the slide fork 20 cannot be accurately measured by the distance sensor 29 at the tip of the insertion direction, the insertion direction base is less affected by the deflection. The distance between the shelf and the slide fork 20 can be accurately measured by the end distance sensor 29. Further, the stacker crane 1 has a function of correcting the deflection of the slide fork 20, and the tip of the slide fork 20 is lifted, and the distance between the shelf and the slide fork 20 can be accurately measured by the distance sensor 29 at the tip in the insertion direction. Even if it disappears, the distance between the shelf and the slide fork 20 can be accurately measured by the distance sensor 29 at the base end in the insertion direction. As a result, the collision between the article and the shelf can be avoided with high accuracy.

  Further, according to the automatic warehouse of the present embodiment, the collision between the article 8 and the shelf can be avoided with a simple structure in which the distance sensor 29 is provided on the slide fork 20. Therefore, it is possible to avoid a collision between an article and a shelf and realize an inexpensive automatic warehouse.

  As mentioned above, although the automatic warehouse of this invention was demonstrated based on embodiment, this invention is not limited to this embodiment. The present invention includes various modifications made by those skilled in the art without departing from the scope of the present invention.

  For example, in the above embodiment, the distance sensor 29 is provided on the upper surface of the slide fork 20 on which the article 8 is placed, and the distance between the upper face and the shelf facing it is measured. The distance between the lower surface and the shelf opposite to the lower surface may be measured. In this case, as the threshold value, a value obtained by subtracting a predetermined value for determining the clearance from a value obtained by subtracting the distance between the slide fork 20 and the shelf from the height of the shelf when the article 8 collides with the shelf is used. And when the distance obtained from the distance sensor 29 is larger than a threshold value, the raising of the lifting platform 16 is stopped.

  Further, in the present embodiment, the distance sensor 29 is provided in the slide fork 20, but the present invention is not limited to this as long as the sensor can measure the distance between the slide fork 20 and the shelf. For example, the slide fork 20 may be provided with an obstacle sensor that detects the presence of an obstacle within a certain distance from the slide fork 20 (within the threshold range of the storage unit 39).

  In the above embodiment, the slide fork 20 is provided with an ultrasonic sensor as the distance sensor 29. However, any distance sensor that can measure the distance between the shelf and the article 8 is used. Not limited. For example, the slide fork 20 may be provided with a photoelectric sensor using light such as a laser distance meter and a photoelectric switch as the distance sensor 29.

  When a laser rangefinder is used as the distance sensor 29, as shown in FIG. 6, a reflector 40 that reflects light emitted from the laser rangefinder with a period is provided on the shelf, and the laser rangefinder is The light from the reflecting plate is received, and the distance between the shelf and the article 8 is measured by checking the phase shift between the received light and the emitted light.

  When a photoelectric switch is used as the distance sensor 29, as shown in FIG. 7, a reflection plate 40 that reflects light emitted from the photoelectric switch is provided obliquely at a predetermined position on the shelf. When the slide fork 20 comes to the detection position, the reflected light from the reflection plate 40 enters the photoelectric switch. The photoelectric switch receives light from the reflection plate and turns from OFF to ON when the amount of received light exceeds a predetermined value. When the photoelectric switch is turned ON or OFF, the collision prevention unit 35 In addition, a command for limiting the movement of the slide fork 20 is generated. In this case, the vertical space between the slide fork 20 and the shelf occupied by the distance sensor can be reduced. Moreover, an inexpensive distance sensor can be realized.

  In the above embodiment, the distance measurement result by the distance sensor 29 is used to determine whether or not the lifting of the lifting platform 16 is stopped. However, the position of the lifting platform 16 may be derived based on the distance measurement result by the distance sensor 29, and the ascending speed of the lifting platform 16 may be controlled based on the derived position, or the scooping and loading. It may be used to control the position of lowering.

  The present invention can be used for an automatic warehouse, and in particular, an automatic warehouse equipped with a stacker crane.

It is a perspective view of the automatic warehouse in embodiment of this invention. It is a figure which shows typically an example of a structure of the stacker crane of the automatic warehouse of the embodiment. It is a figure which shows the structure of the slide fork of the stacker crane of the same embodiment in detail. It is a block diagram which shows the functional structure of the automatic warehouse of the embodiment. It is a flowchart for demonstrating the conveyance operation | movement of the articles | goods in the automatic warehouse of the embodiment. It is a figure which shows in detail the structure of the slide fork of the modification of the stacker crane of the embodiment. It is a figure which shows in detail the structure of the slide fork of the modification of the stacker crane of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stacker crane 2 Rack 3 Station 4 Rail 8 Goods 11 Lower trolley 12 Upper trolley 13 Mast 14 Wheel 15 Traveling motor 16 Lifting stand 17 Winch motor 18 Sheave 19 Wire rope 20 Slide fork 21 Plate 22 Transfer motor 23 Control device 29 Distance sensor DESCRIPTION OF SYMBOLS 30 Mechanism part 31 Control part 32 Display part 33 Input part 34 Communication I / F part 35 Collision prevention part 36 Threshold value determination part 39 Memory | storage part 40 Reflector

Claims (5)

A rack having a shelf for storing articles;
A transfer section for putting articles into and out of the shelf;
A control unit for controlling the operation of the transfer unit,
The transfer unit is
A movable part on which the article is placed and enters and exits the shelf;
A distance sensor that is provided at an insertion portion that is inserted into the shelf of the movable portion, and that measures a vertical distance between the insertion portion of the movable portion and the shelf;
The distance sensor is provided on an upper surface on which the article is placed in an insertion portion of the movable part,
The said control part stops the raising operation | movement of the said transfer part, when the distance measured by the said distance sensor is smaller than a threshold value. The automatic warehouse characterized by the above-mentioned. 2. The automatic warehouse according to claim 1, wherein the distance sensor is provided at a distal end portion and a proximal end portion in an insertion direction of the movable portion in an insertion direction of the shelf. The automatic warehouse according to claim 1 or 2 , wherein the distance sensor is an ultrasonic sensor that transmits ultrasonic waves to the shelf and receives ultrasonic waves reflected from the shelf. The rack further includes a reflector that is provided on the shelf and reflects light from outside the shelf,
The automatic warehouse according to claim 1 or 2 , wherein the distance sensor is a photoelectric sensor that irradiates light to the reflection plate and receives light from the reflection plate. The photoelectric sensor is a photoelectric switch that is turned on or off when the amount of received light exceeds a predetermined value,
Wherein the control unit, automatic warehouse of claim 4, wherein the photoelectric switch when ON or OFF, characterized in that the upward movement of the transfer unit Ru is stopped.

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