CA1105849A - Automated storage and retrieval system - Google Patents

Automated storage and retrieval system

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Publication number
CA1105849A
CA1105849A CA309,118A CA309118A CA1105849A CA 1105849 A CA1105849 A CA 1105849A CA 309118 A CA309118 A CA 309118A CA 1105849 A CA1105849 A CA 1105849A
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Canada
Prior art keywords
storage
conveyor
location
racks
address
Prior art date
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Expired
Application number
CA309,118A
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French (fr)
Inventor
Lee Z. Hall
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Palmer Shile Co
Original Assignee
Palmer Shile Co
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Abstract

ABSTRACT OF THE DISCLOSURE
An automated storage and retrieval system that greatly facilitates the handling and processing efficiency of material stored in a warehouse. The present system includes an electronically controlled storage/retrieval machine that is adapted to either retrieve material stored in storage racks and transport the material to a pro-cessing area, or store material retrieved from the processing area in the storage racks. The system is designed so that material can be passed back and forth through the racks to and from the processing area. In this manner, the processing area is not relegated to the limited space available at the ends of the aisle between the racks.
In addition, the storage/retrieval machine is equipped with an optical scanner that is adapted to read identification codes appearing on the storage cassettes to insure that the intended loads are being transported. This greatly reduces the possibility of lost or misplaced loads.

Description

5~9 Background and Summary of the Invention The present invention relates to a storage and retrieval system and in particular to an improved system design that maximizes the use of available storage space and provides increased materials handling flexibility.
In the vast majority of storage warehouses, much of the total available storage space within the facility is either not used or is used in an inefficient manner. Moreover, in storage facilities where a greater percentage of the available space is utilized, the material is usually stored in a manner that makes access to some of the material extremely difficult.
This, of course, increases the cost of storage and often leads to problems of lost or misplaced material. Unfortunately, too often the "solution" for such inefficiency is not the improve-ment of the existing facility, but rather the construction of additional facilities.
Many different types of automated storage and retrieval systems have been proposed to improve the overall operating efficiency of storage facilities. The semi-automated systems initially proposed still required a substantial amount of hand labor, and therefore were subject to the disadvantages inherent in the use of manual labor. However, the continued reliance upon manual labor also provided these systems with a great deal of flexibility. As the more sophisticated fully automated systems were developed, the efficiency of the storage facilities improved, but the flexibility of the systems suffered. For example, the development of the present generation storage and retrieval machine in combination with the more advanced types of rack structures currently being used greatly improved storage efficiency. However, a storage and retrieval machine operating between two rows of racks can transport material retrieved from the racks only as far as the ends of the aisle.
Consequently, in some prior art systems, all material
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processing was t~pically conducted on a single conveyor posi-~ioned transversely to the racks at the end of the aisle. In an effort to improve upon this system, a "carousel" arrangement of conveyors at the end of the aisle was proposed so that more than one load of material could be accommodated in the process area at a given time. However, the flexibility of this system was still limited and the congestion problems caused by the necessity of having to perform all of the shipping, receiving, and machining operations in a single area remained.
Thus, it is the primary object of the present invention to provide a storage system that combines the efficiency of a fully automated system with the operating flexib.ility of a manual system. More particularly, the system is adapted to receive incoming material at a receiving area where the material can be unloaded by an overhead crane and placed into empty cassettes on conveyors positioned adjacent the first row of storage racks. From there, the loaded cassettes are moved off the conveyors and into the adjoining rack bays. The storage and retrieval machine located on the opposite side of the first row of racks then retrieves the loaded cassettes and stores them in the designated bin locations under the control of the main control center. Similarly, when a cassette is to be retrieved from a rack and placed on a conveyor, it is passed back through the first row of racks. Thus, since material processing is no longer conducted at the ends of the aisle, it is possible to provide as many loading and shipping con-veyors as necessary to efficiently handle incoming and outgoing material.
Ir~ a~dition, special double conveyors are provided to service the designated work areas in the system. Initially, the desired material is loaded by the storage/retrieval machine onto the outboard one of the double conveyors by passing the cassette ~hrough the rack as before. From there, the workman transfers the material to the inboard conveyor where the work operation is performed. This permits the S/R machine to load a seconcl cassette onto the outboard conveyor while the machinist is working on the first load. After the work is completed, the first load is transferred back through the rack to the S/R machine and the second load is transferred from the outboard conveyor to the inboar~ conveyor. In this manner, it can be seen that the operator of the control console can keep the machinist continuously supplied with material, rather than requiring the workman to wait while the S/R machine returns the first load before a second load can be retrieved.
In order to minimize the possibility of lost loads, the storage/retrieval machine of the present invention is pro-vided with an optical scanner that is adapted to read and decode bar-coded information appearing on labels placed on the storage cassettes to uniquely identify each cassette. The information read from a cassette during a "STORE" operation is fed back to the ground console where it is checked against the instructional information provided to the storage/retrieval machine to insure that the proper load is being stored. This checking system greatly reduces the chances of misplacing a load as well as providing an immediate indication of an error condition before the error is compounded.
The entire system is adapted to be controlled and monitored by an electronic control unit. The front panel of the control unit or ground console contains a series of "STORE"
and "RETRIEVE" buttons actuable by the operator to control the movement of the storage/retrieval machine. In particular, a pair of "STORE" and "RETRIEVE" buttons is associated with each conveyor in the system. Thus, if a particular cassette is to be loaded onto conveyor No. 1, for example, the "RETRIEVE"

button associated with conveyor No. I would be actuated. The "address" information of each conveyor -- i.e., its horizontal and vertical location, the side of the aisle it is on, and its laod capacity -- is preset for each particular system so that whenever a "STORE" or "RETRIEVE" button is activated, the information establishing the location of the selected conveyor is automatically provided to the microprocessors which instruct the movement of the storage~retrieval machine.
The "address" information of each cassette in the system is contained on standard IBM computer cards. A separate computer card is provided for each cassette and contains the cassette's horizontal and vertical location in the racks, the side of the aisle it is on, and the unique identi-fication number of the cassette (which matches the bar-coded number on the cassette). The card is inserted in a card reader on the front panel of the ground console prior to activation of one of the "STORE" or "RETRIEVE" buttons.
The ground console which controls the operation of the storage/retrieval machine, always runs through a complete cycle comprising the operations: (1) go someplace and pick up a cassette; and (2) go someplace else and drop it off. Thus, the storage /retrieval machine operates in two half cycles, one half cycle under the control of the information from the card reader and the other half cycle under the control of the preestablished conveyor location information. Whether the conveyor address or the card reader will control the first half cycle g f Operation depends upon whether a "STORE" or "RETRIE~E"
button has been actlvated. If a "RETRIEVE" button is selected, the ground console will first instruct the S/R machine to retrieve the cassette located at the address determinea by the information from the card reader, and then to proceed to the appropriate conveyor location and deposit the cassette.
Conversely, if a "~TORE" button is activated, the ground console will instruct the S/R machine to first proceed to the appro-priate conveyor location, pick up the cassette and store it in the rack location determined hy the address information from the card reader.
In the preferred embodiment, the ground console i5 also provided with a group of status lights located adjacent to each pair of "STORE" and "RETRIEVE" control buttons to provide a visual indication of the current status of each conveyor. In this manner, a single operator can readily I monitor all of the conveyors in the system. In addition, a numerical display is also provided which is adapted to display a predetermined error code whenever any of several identifiable fault conditions occur.
Broadly speaking and in summary of the above the present invention may be seen as providing in an automated storage and retrieval system including a storage area comprising at least first and second locations, a processing area having a plurality of conveyors located adjacent storage locations in the first row of storage racks, transfer means operatively associated with each of the conveyors for transferring material from the adjac~nt storage locations onto the conveyors and from the conveyors into the adjacent storage locations, and a storage and retrieval machine adapted to travel along the aisle defined between the first and second rows of storage racks and retrieve material from a first location in the 5~
storage racks and deposit the load .in a second location in the sto.rage racks, the improvement comprising:
control means for controlling the operation of the storage and retrieval machine including a control panel having a plurality of status lights associated with each conveyor in the processing area for indicating to the operator the status of each of the conveyors, including a first light that is activated when material is deposited by the storage/
retrieval machine into the storage location adjacent the conveyor, a second light that is activated when material is deposited onto the conveyor, a third.light that is activated when material is transferred by the transfer means from the conveyor into the storage location adjacent the conveyor, and a fourth light that is activated when both the conveyor and the adjacent storage location are empty.
The present invention may also be seen as providing in an automated storage and retrieval system including a storage area comprising at least first and second parallel rows of storage racks each haying a plurality of storage locations, a processing area having a plurality of conveyors located adjacent storage locations in the first row of storage racks, transfer means operatively associated with each of the conveyors for transferring material from the adjacent storage locations onto the conveyors and from the conveyors into the adjacent storage locations, and a storage and retrieval machine adapted to travel along the aisle and retrieve material from a first location in the storage racks and deposit the load in a second location in the storage racks, the improvement com-prising:
control means for controlling the operation of the stora~e and retrieval machine in accordance with a first ~7 -address which designates the location in the storage racks .
where the s'orage/retrieval machine is to proceed to retrieve a desired load of matexial and a second address which designates the location in the storage racks where the storage/retrieval machine i5 to proceed to deposit the desired load of material, including a control panel haYing ~irst and second contxol switches associated with each single conveyor, the first con-trol switch being operative to designate the location of the storage location adjacent the respective conveyor as the first address when activated and the second control switch being operative to designate the location of the storage location adjacent the respective conveyor as the second address when activated, and input means for designating the second address when the first control switch is activated and the first address when the second control is activated.
~ ~ Further objects and advantages of the present inven-tion will become apparent from a reading of the detailed des-cription of the preferred embodiment which makes reference to the following set of drawings in which:
Brief Description of the Drawings Figure 1 is a plan view of a storage system embodying the teachings of the present invention;
Figure 2 is an end view of the storage system shown in Figure l;
Figure 3 is a sectional view of the storage racks shown in Figure 1 taken along line 3-3;
Figure 4 is a plan view of the preferred layout of the front panel of the ground console;
Figure 5 is a perspective view of the optical scanner of the present invention;
Figure 6 appearing on the same sheet as Figure 3, is a view of an exemplary bar code lable of the type appearing on the cassettes;

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Figure 7 is a block diagram of the electronic control circuit of the present invention; and Figure 8 is a more detailed block diagram of the ground console block of the control circuit shown in Figure 7.
Detailed Descri tion of the Preferred Embodiment P
Looking to Figures 1 and 2, an exemplary layout of a storage facility according to the present invention is shown.
The storage system illustrated and described herein is particul-arly suited for the storage and handling of straight stock in a steel warehouse. However, as will subsequently become apparent to those skilled in the art, the teachings of the present invention are readily adaptable to use in a wide variety of storage applications requiring a greater or lesser degree of storage and processing capabilities.
The storage facility illustrated in Figures 1 and 2 has a receiving area 12 and a shipping area 14. Incoming mater-ial is transported from the receiving area 12, and outgoing material is transp~rted to the shipping area 14, by an overhead crane lS which is , ~
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adapted to operate above the processing area as indicated in Figure 1. Materia] is typically brought to the storage facility by rail car 16 or by truck 18. lhe incoming material is then unloaded from the railway car 16 or truck 18 by the overhead crane 15 and deposited onto empty cassettes 32 located on the loading conveyors 20. I`he loading conveyors 20 are positioned adjacent the first row of racks 30 in aligned arrangement with the rack openings 22 at the height of the conveyors 20.
Although only two loading conveyors 20 are shown, additional conveyors may be provided if required.
Once the material has been loaded onto an empty cassette 32 on one of the conveyors 20, the next step in storing the material is to transfer the cassette 32 into the aligned rack opening 22 adjacent the conveyor 20. Referring momentarily to Figure 3, an end view of the racks 30 is shown. As can be seen from the drawing, the racks 30 comprise a plurality of storage bins 24 stacked atop one another between the floor 26 and the ceiling 28 of the building. In the preferred embodiment illustrated herein, there are 46 bays per row and 22 shelves per bay. The width and depth of each storage bin 24 is the same, however, the heights of the bins 24 vary from 12 inches to 21 inches. Importantly, it will be noted that the bin opening 22 at the height of the loading conveyors 20 through which cassettes are passed is at least as large as the largest bin size in the racks so that all of the various sized cassettes can be accommodated.
Returning to Figure 2, each of the input/output conveyors 2~48 is equipped with a "grabberl' machanism 35 that moves along the length of th~ conveyor 20~48 and is adapted to either push a cassette 32 into the first ~ow of racks 30 or pull a cassette 32 out of the first row of racks 30. It will be noted at this point that the length of the cassettes 32, wllich are all equal is greater than the depth of the storage racks 30/50. In this manner when the cassettes 32 are deposited into the racks 30/50 the ends of the cassettes will protrude slightly from the racks 30/50 as shown in Figure 1.
This permits the grabber mechanism 35 on the conveyors 20/48 to engage the end o~ the cassette 32 that protrudes from the racks 30.
Once a cassette 32 has been transferred from a loading conveyor 20 into the aligned rack opening 22 adjacent the conveyor 20 the cassette 32 is then drawn onto the storage/
retrieval machine 40 on the opposite side of the first row of racks 30. The storage/retrieval machine 40 is equipped with a mechanism commonly referred to as a "table" 41 that is adapted to move in and out of the rack openings to store and retrieve cassettes 32. The table 41 on the storage/retrieval machine 40 also includes a grabber mechanism similar to that on the input/output conveyors 20/48 for engaging the ends of the cassetes 32 extending from the racks 30. Upon retrieving a loaded cassette 32 from the storage bin 22 adjacent a loading conveyor 20 the storage/retrieval machine 40 is then adapted to automatically store the loaded cassette 32 into a predetermined bin location under the control of the ground conso].e 45. The storage/retrieval machine 40 operates along a depression in the floor between the two rows of racks 30 and 50 referred to as a "pit" 42. The movement of the machine 40 as noted, is electronically con-trolled by the control or ground console 45. The ground console 45 controls all three axes of movement of the storage/retrieval machine 40; horizontal and vertical movement of the machine 40 between the two rows o~ racks 30 and 50 and the movement of the table 41 into an~ out of the racks 30/50 to store and retrieve the cassettes 32. .~s will subsequently be explained in greater detail the ground console 45 also controls the speed of the storage/retrieval machine 40 in accordance with the distance the machine is from the desired rack location.
The storage/retrieval machine 40 provides position feedback information to the ground console 45 via a pair of absolute encoders 43 and 47. The encoders utilized in the preferred embodiment are manufactured by Vernitron Corp., mfgr. No. OADC-30/5/BCDQ(200)L. One encoder 43 is utilized to provide vertical position feedback information, and the other 47 is utilized to provide horizontal position feedback informa-tion. As best illustrated in Figure 2, the vertical position encoder 43 is mounted to the table 41 of the storage/retrieval machine 40 and is adapted to engage a vertical guide rail fastened to the machine 40. The horizontal position encoder 47 is mounted to the base of the storage/retrieval machine 40and is adapted to engage a horizontal guide rail secured to the side wall of the pit 42. In this manner, the ground console 45 can control the movement of the storage/retrieval machine 40 without having to count rack openings 24, thus permitting accurate alignment of the table 41 with the rack openings regardless of the size or locati.on of the rack openings 24.
In addition, the use of encoders eliminates the necessity of having to return the storage/retrieval machine 40 to a base location following a power shutdown or manual operation.
To retrieve stored material for shipment, the operator of the ground console 45 merely instructs the storage/retrieval machine 40 to retrieve the desired material from its storage location in the racks 30/50 and insert the loaded cassette 32 into a bin location in rack 30 aligned with one of the shipping conveycrs 48. From there, the grabber mechanism 35 on the conveyor 48 draws the loaded cassette 32 onto the conveyor 48 where the material is banded and tagged for shipment. The material is then removed from the cassette 32 and loaded onto a waiting truck or freight car by the overhead crane 15 and the empty cassette 32 either returned to its rack loeation or transferred to one Or the loadillg conveyors 20 for receipt of additional incoming material.
Significantly, it will be noted that the provision of a plurality of shipping conveyors 48 (herein four) provides the present system with a substantial amount of flexibility in handling the shipment of material. For example, one or more of the shipping conveyors 48 can be used exclusively to main-tain a supply in the shipping area 14 of the types of material in the greatest demand. In this manner, the time of the storage/
retrieval machine 40 is not consumed by the repeated storage and retrieval of the same material as would otherwise be necessary to insure the availability at all times of an unoccupied shipping conveyor 48. In addition, if an order is received for only a few pieces of several different types of material, the storage/retrieval machine 40 can deposit a load of each type of material on one of the conveyors 48 so that the desired pieces can be processed and loaded at the same time.
In addition, the present storage system also provides efficient means for handling and transporting material to and from a designated work area. In steel warehouses, for example, orders are frequently received for custom material which must be individually machined. Thus, special work areas easily accessible by the storage/retrieval machine 40 must be provided where such machining opera~ions can be performed. ~loreover, since warehouse machines of this type are usually quite expensive, it is important from a cost standpoint, that the machi~es ~e kept as busy as po~sible. Accordingly, to satisfy these requirements, the present system includes special double conveyors 44/46 that are adapted to service a designated work area, herein a pair of saw stations 47, in the processing area.

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As will be appreciated by those skilled in the art, the double conveyors 44/46 provide a means of maintaining a continuous supply of material at the workstations 47. In particular, the material to be machined is initially retrieved by the storage/
retrieval machine 40 from its designated rack location and inserted into the bin 54 aligned with either of the two out-board conveyors 44. The loaded cassette is then drawn through the racks 30 and onto the outboard conveyor 44. Once the cassette is loaded onto the outboard conveyor 44, it is now under the control of the workman at the workstation 47. When the workman is ready to work on the material contained in the cassette on the outboard conveyor 44, the cassette is transferred to the inboard conveyor 46 from where the material can be individually handled and machined. Once a cassette has been transferred from the outboard conveyor 44 to the inboard conveyor 46, another cassette can be loaded onto the outboard conveyor 44 and a third cassette inserted into the now vacant bin 54 by the S/R
machine 40. Thus, when the workman has completed machining the material from the first cassette, the cassette on the inboard conveyor 46 can be transferred back into the racks 30 through the aligned bin location 56 to the storage/retrieval machine 40, the loaded cassette on the outboard conveyor 44 trans-ferred to the inboard conveyor 46, and the third cassette loaded onto the outboard conveyor 44 from bin 54. In this manner, it can be seen that the workman is not required to wait for the storage/retrieval machine 40 to store the finished material before the next load of material can be retrieved and trans-ported back to the workstation 47. Accordingly, the efficiency of the workman and the machines are improved.
Referring now to Figure 4, a pl~n view of the preferred layout of the front panel of the control console 45 is shown.
As can be seen from the drawing, the control console 45 contains ~s~

a pair of controi buttons 60 and 62, labeled "STORE" and "RETRIEVE", for each input/output conveyor 20/48~ an~ a pair of control buttons for each set of double conveyors 44/46. Ihe control buttons appearing in phantom are shown to indicate that additional sets of control buttons can be accommodated if additional conveyors are utili~ed. The control buttons 60 and 62 associated with eacll conveyor are u~ilized to direct the movement of cassettes to and from that conveyor. Specifically, if a cassette is to be loaded OlltO a particular conveyor, the "RETRIEVE" button associated with that conveyor is actuated.
Similarly, if a cassette is to be removed from a conveyor and stored in the racks, the "STORE" button associated with that particular conveyor is depressed.
Located above each pair of conveyor control buttons 60 and 62 is a set of status lights 64 which are adapted to provide the console operator with complete in-formation as to the current status of each conveyor in the system. In particular, each of the individual input/output conveyors 20/48 has associated therewith four status lights: (1) store, (2) empty, (3) ready, and (4) full. The double conveyors 44/46 that service the workstations 47, on the other hand, have six status lights:
(1) empty, (2) ready, and (3) full, associated with the out-board conveyor 44, and (4) store, (5) empty, and (6) full, associated with the inboard conveyor 46. When a cassette is placed into the rack bin adjacent one of the conveyors by the storage/retrieval machine 40, the "READY" light associated with that conveyor will go on. The "FULI," light will turn on when the cassette is transferred from the rack onto the con-veyor. When the cassette is returned to the adjacent rack bin, the "STORE't light will go on. And ~inally, when the storage/
retrieval machine 40 retrieves the cassette from the bin for storage, the "EMPTY" 'ight will turn on. The status lights associated with the dcublc conv~ctrs 44/~6 f~lnction in an 5~9 identical manner with the fol]owing two exceptions. A "store"
status light is not required for the outboard conveyors 44 because a cassette is never removed from an outboard conveyor 44 by the storage/retrieval machine 40 for storage. Similarly, a "ready" status light is not required for the inboard conveyors 46 because the storage/retrieval machine 40 never loads a retrieved cassette onto an inboard conveyor 46.
As noted previously, the ground console 45 which con-trols the movement of the storage/retrieval machine 40, always runs through a complete cycle comprising the functions: "go someplace and pick up a cassette; go someplace else and drop it off." Thus, for each "STORE" or "RETRIEVE" instruction, the storage/retrieval machine 40 must be provided with two address locations: the address location of the place where the cassette is to be picked up and the address location of the place where it is to be dropped off. The address information required for each operating cycle is provided by the card reader 66 and the preset conveyor address information contained in the control console 45. The card reader 66 is adapted to extract address information from a plastic adaptation of a standard IB~I computer card. Initially, a separate computer card is prepared for each storage location in the racks 30/50. Each card contains the following information: (1) the horizontal and vertical address location of the storage bin, (2) the side of the aisle it is located on, and (3) the identification or bar-code number of the cassette located therein. The address information relating to each conveyor, comprising: (1) horizontal and vertical location, (2) the side of the aisle, and (3) load capacity, is preset into the console 45 for each system layout and automati-cally provided to the control circuitry whenever the "STORE" or "RETRIEVE" button associated with a particular conveyor is activated. Whether the preset conveyor address information or p~s~9 the address information from the card rea~er will control the irst half cycle of operation of the storage/retrieval machi]le 40 depen~s upon whether the "STORE" or "RETRIF.V~" button is activated. Specifically, if the "RETRIEVE" button 62 is depressed, the ground console 45 will instruct the storage/
retrieval machine 40 to initia]ly proceed to the bin location determined by the address information from the card reader 66, retrieve the cassette stored therein, and then deposit the cassette in the bin location in rack 30 adjacent the designated conveyor. Conversely, if the "STORE" button 60 is activated, the storage/retrieval machine 40 will retrieve the cassette from the designated conveyor first before proceeding to the bin location determined by the address information from the card reader 66 to store the cassette therein.
Thus, to instruct the storage/retrieval machine 40 to perform either a "store" or "retrieve" operation, the operator first selects the computer card associated with the desirecl cassette, inserts the card into the card reader 66, and then depresses ei~her the "STORE" or "RETRIEVE" button associated with the selected conveyor. For convenience, the preferred control console 45 also includes a plurality of cardholders 68 located immediately above each pair of control buttons 60 and 62 for storing the address card of a cassette after it has been deposited on one of the conveyors. In this manner the possi-bility of accidently inserting the wrong address card into the card reader 66 when the cassette is to be ret~rned to its designated rack location is greatly reduced. Consequently, the chances of misplacing or losing a load are reduced.
When instructing the movement of the storage retrieval machine 40~ the oper~tor of the control console 45 must be cognizant of the status of the selected conveyor to be involved in the instruction. Specifically, before a "STORE" command from a particular -onveyor can be properly executed, the "STORE" status light associated with that conveyor must be on. Similarly, in order to properly execute a "RETRIEVE"
command to a particular conveyor (except to one of the out-board conveyors 44), the "EMPTY" status light associated with that conveyor must be on. If the status of the selected conveyor is wrong for a chosen command, the "COMMAND ERROR"
light 74 will go on when the "STORE" or "RETRIEVE" button for that conveyor is pushed. The "COMMAND ERROR" light 74 indicates to the control operator that the cammand has not been accepted by the control unit 45.

.len a E~roL~er com~and is entered, the "I~l CYCI.F" light 78 will turn on indicatiTIg that tile storage/retrieval machi.ne ~0 is executing the command.
If during the performance of a command the control unit 45 detects an error condition which prevents th~ cycle from continuing,-the "C~CLE ERROR" light 76 will be activated.
Contemporaneously, the control unit 45 is adapted to generate an error code identifying the type of error detected and dis-play the error code on the console at 75 ~xamples of detect-able error conditions include:
(1) store an oversized load (2) store a load into a full rack location;
(3) the casette identification code does not agree with the identification code on the computer card.However, as w.ill be readily apparent to those skilled in the art, the present system can be easily adapted to detect numerous other types of error conditions depending upon the requirements of the particular storage facility, As a means of significantly reducing the possibility of lost loads, the present storage system incorporates a novel op-tical scanner 70 located on the storage/retxieval machine 40 that is adapted to read the identification codes appearing on the cassettes, When the system is .initially set up, a label containing a unique bar code is placed in a predetermined location on each cassette. In addition, the identification number represented by the bar code is entered on the computer card associated with that cassette, Thus, before the storage/retrieval machine 40 will execute a STORE instruction and retrieve a cassette from a con-veyor, the cassette identification code read by the scanner must agree wi.th the identification number on the computer card. In : particular, the microprocessor in the ground console, to be sub~
sequently described is programme to compare the identification ~17~
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~5~'~9 ,lumber read off the computer card by the card reader with the i.dentification number read by the scanner. If the two num~ers do not match the microprocessor is further programmed to instruct the S/R machine 40 to return the cassette to the pass-through rack opening adjacent the conveyor where the casse~te was picked up. Contemporaneously, the "CYCLE ERROR" the light 76 is activated and the identification code read by hhe scanner 70 is displayed on the error code display 75, The optical scanner utilized in the preferred embodi-ment comprises a low power laser scanner 70, shown in Fi.gure 5, that is mounted to the storage/retrieval machine 40 in a pre-determined location so that the scanner 70 will be able to read the bar codes on the cassettes when the storage/retrieval machine 40 is properly positioned adjacent a cassette, As the drawing indicates, the position of the scanner is important since the scanner 70 has a limited "reading area" 72, The scanner 70 utilized in the preferred embodiment is manufactured by Computer Identics Corporation, Model 6000, and has an optical throw of six inches, a field depth of six inches, and a scan height of 12 inches, Thus, the effective reading area 72 of the scanner 70, as indicated by the shaded portion in the drawing, comprises a 6" x 12" rectangular area, The optical scanner 70 is adapted to illuminate passing objects with a sweeping laser beam and convert the reflected light signal into an electrical analog signal, The analog signal is then provided to a decoding and conversion circuit 73, which converts the analog signal to a digital signal and examines the signal to determine if it meets the proper criteria for a signal reflected from a valid code . pattern. If it is determined that the signal is valid, the digital signal is conditioned for transmission to the control . console 45, The decoding and conversion circuit 73 ut;.lized in the preferred embodiment is also manufactured by Computer Identics Corporation as part of the optical scanning sys-tem S~

and is referred to by the manufacturer as a "I)ecodatran".
With reference to Figure 6, the format of the bar code utili~ed in the preferred embodiment is illustrated. As can readily be seen from the drawing, the bar code employed herein is similar to that frequently appearing on the packages of many types of consumer products. In the present system, a plastic label con+aining the identification code is placed on the side of each cassette used in the storage facility.
The identification code, of course, defines a different five digit number for each cassette. In this manner, when the storage/retrieval machine 40 is instructed to store a particular cassette, the bar code on the cassette can be read by the optical scanner 70 and the identification number checked with that appearing on the computer card for that cassette, to insure that the proper cassette is being stored.
This procedure greatly reduces the possibility of lost loads and consequently improves the operating efficiency of the system. It is to be understood, that although the present optical scanning system is adapted to read the bar code located on the cassette only during a "STORE" instruction, the present system can be readily adaptable to check the cassette identification code during a "REIRIEVE" instruction as well.
The output instructions entered by the operator of the ground console 45 are provided to an electronic control circuit which processes the instruction signals and provides directive output signals which control the movement of the storage/retrieval machine 40. Looking to Figure 7, a block diagra~ of the control circuit 80 used in the preferred embodiment is shown. At this point, it should be understood that the implementation of the electronic control for the present invention can be accomplished in numerous different 5~

ways, depending upon the approach of the particular designer.
Accordingly, only a description of the block diagram illustrating the general approacll taken in the preferred embodiment will be provided.
As can be readily seen from the drawing, the control circuit 80 employs three separate microprocessors, one to control each axis of movement. In particular, a first micro-processor 8Z controls horizontal movement of the storage/
retrieval machine 40, a second microprocessor 84 controls vertical movement of the machine 40, and a third microprocessor 86 controls movement of the table 41. The horizontal, vertical, and table sections of the electronic control unit 80 operate in essentially the same manner, therefore, the following description of the horizontal section applies equally to the vertical and table sections. The a.c. inputs block 90 represents a series of converter circuits that receive signals from the storage/retrieval machine 40 and convert these 120 volt a.c. signals to five volt d.c. signals. The a.c. input signals from the storage/retrieval machine 40 are also optically isolated from the d.c. output signals, as is conventional in machine control circuits of this type. The d.c. output signals are either a logic HI or a logic LO to indicate either the presence or absence of the corresponding a.c. input signals.
The d.c. output signals from the a.c. inputs block 90 ~;
. are provided to an input interface block 92 which comprises a series of tri-state gates that serve to gate the information received from the storage/retrieval machine 40 for entry into the microprocessor 82. The input interface block 92 also gates the information received from the ground control 88 to be provided to the microprocessor 82. The microprocessor 82 "reads" the information interfaced by the input interface :~:

block 92 by providing an appropriate signal code on the address buss line llO which enables the tri-state gates in the input interface block 92, thereby placing the data from the input interface 92 on the data buss line 112.
The microprocessor 82 instructs movement of the storage/retrieval machine 40 via a return path through the output interface block 98 and the a.c. outputs block 96. The output interface block 98 comprises a series of latch circuits (i.e. flip-flops) that are adapted to latch the information present on the data buss line 112 when enabled by the appro-priate signal code on the address buss line l10. The latched d.c. logic information is then converted back to 120 volt a.c.
signals by the a.c. outputs block 96. The a.c. outputs block 96 has -four outputs -- forward (slow), reverse (slow), high speed, and medium speed, -- which control the horizontal speed and direction of the storage/retrieval machine 40.
The microprocessor 82 receives feedback information relating to the actual position of the storage/retrieval machine 40 from the horizontal encoder 47. The output information from the encoder 47 is latched by the position encoder interface block 100 which is enabled every few milliseconds by a strobe signal received from the micro-processor 82. The microprocessor 82 compares the actual position of the storage/retrieval machine 40 as determined by the encoder 47 with the desired location of the machine 40 as determined by the instructional information from the ground control 88. If additional movement is required, the microp~ocessor 82 instructs ~ovement of the storage/retrieval machine 40 accordingly via the a.c. outputs . ~

~s~
block 96, The microprocessor 82 also determines the speed at which the storage/retri~val machine 40 should move to the desired location in accordance with the distance the machine 40 is away from the desired location. If the storage/retrieval machine 40 is beyond a first distance, then the microprocessor 82 will instruct the machine 40 to move at a hiyh rate of speed until it is within a second predetermined distance from the desired location, at which point the microprocessor 82 will instruct the machine 40 to slow to a medium speed, Further, when the storage/
retrieval machine ~0 has converged to within a third prffletRrr.~ned distance of the desired location, the microprocessor 82 will instruct the machine 40 to slow to its slowest speed from which it can come to a complete stop when the desired location i5 reached, These predetermined distances are set by the digit switch module 102 which comprises a plurality of range switches that can be set to any desired distance in accordance with the mass of the storage/retrieval machine 40, In addition, the pre-ferred embodiment of the control circuit 80 utilizes thumb wheel microswitches which can be readily adjusted by the operator. In this manner~ the distance settings can be easily altered by the operator without having to change the softward of the system to insure th~t the storage/retrieval machine 40 travels to the desired location in a minimum amount of time.
The programma~le read-only memory block (PROM) 104 contains the softward for the microprocessor 82, and the master control block 106 represents conventional buffering and inverter ; logic circuitry, interfaces to the microprocessor 82, as well as on the control lines from the status flag displays and interrupt controls, The display interface 108 is an optional circuit that is required if a display terminal is desired.

-22~

The vertical section of the control circuit 80 operates identically to the horizontal section. The table section, however, includes a scanner interface block 115 in place of the position encoder interface 100, which receives the serial output si~nals from the optical scanner 70 located on the storage/retrieval machine 40 and converts the infor-mation to parallel digital output signa]s which are provided on the data buss line 116 to the microprocessor S6. As pre-viously noted, the microprocessor 86 is programmed to compare the information received from the optical scanner 70 with the identification information received from the card reader on the ground control 88. If the information from the two sources does not agree, an error signal is generated.
Referring now to Figure 8, a more detailed block diagram of the ground control circuit 88 is shown. Since the circuitry is duplicated for each conveyor in the system, only one setup will be described. The conveyor controls block 120 represents a group of relays which provide status signals from the conveyor indicating the four status conditions visually displayed on the control panel. The outputs from the conveyor controls block 120 are provided to an a.c.
inputs block 122 which converts the incoming a.c. signals to d.c. logic levels. The a.c. inputs block 122 also receives and converts the output signals from the STORE and RETRIEVE
pushbuttons 124 associated with that conveyor. In this manner, a direct interlock is provided to insure that the particular instructions selected can be performed given the - current status of the conveyor. Thus, as previously noted, a bad command will not be accepted. The d.c. logic signals from the ~ c~ inpu~s b~ock 122 along with the preset conveyor address information from block 126, , -~s~
tre provicled to t-he c3round control ci.rcuit 128 In addition, the ground control circuit 128 is also provided with the cassette address informati.on from the outpu-t of the card reader 130, 17hen a STORE or RETRIEVE button for a particular conveyor i6 actuated, all of the other conveyors connected to the ground control circuit 128 are locked out, Thus, if ada-itional control buttons are pushed before the storagejretrieval machine 40 has completed its operating cycle, the instructions will be iqnored. The ground control circuit 128 is adapted to determine, in accordance with the instruction entered~ whether the storage/retrieval machine 40 is to proceed to the conveyor address or to the cassette address first, and to provide to the electronic control circuit 80 the necessary address information in thè appropriatè order Specifically, as previously discussed, iE a STORE
button is actuated, the conveyor address indicates the location where the S/R machine 40 must first proceed to retrieve the desired cassette, and the cassette address indicates the rack location where the S/R machine 40 must then proceed to deposit the cassette. Similarly, if a RETRIEVE button is actuated, the cassette address indicates the location where the S/R
machine 40 must first proceed to retrieve the desired cassette and the conveyor address indicates the conveyor location where the S/R machine is to deposit the cassette ~ hile the above description constitutes the preferred embodiment of the invention, it will be appreciated that the invention is ~24-.
~' S~

susceptible to modification, variation and change without departing from the proper scope or fair meaning of the accompanying claims.

Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In an automated storage and retrieval system including a storage area comprising at least first and second parallel rows of storage racks each having a plurality of storage locations, a processing area having a plurality of conveyors located adjacent storage locations in said first row of storage racks, transfer means operatively associated with each of said conveyors for transferring material from said conveyors into said adjacent storage locations, and a storage and retrieval machine adapted to travel along. the aisle defined between said first and second rows of storage racks and retrieve material from a first location in said storage racks and deposit said load in a second location in said storage racks, the improvement comprising:
control means for controlling the operation of said storage and retrieval machine including a control panel having a plurality of status lights associated with each conveyor in said processing area for indicating to the operator the status of each of said conveyors, including a first light that is activated when material is deposited by said storage/
retrieval machine into the storage location adjacent the conveyor, a second light that is activated when material is deposited onto the conveyor, a third light that is activated when material is transferred by said transfer means from the conveyor into the storage location adjacent the conveyor, and a fourth light that is activated when both the conveyor and the adjacent storage location are empty.
2. The automated storage and retrieval system of Claim 1 wherein said control means is adapted to control the move-ment of said storage/retrieval machine in accordance with a first address which designates the location in said storage racks where said storage/retrieval machine is to proceed to retrieve a desired load of material and a second address which designates the location in said storage racks where said storage/retrieval machine is to proceed to deposit said desired load of material.
3. The automated storage and retrieval system of Claim 2 wherein said control panel further comprises first and second control switches associated with each single conveyor, said first control switch being operative to desig-nate the location of the storage location adjacent the res-pective conveyor as said first address when activated and said second control switch being operative to designate the location of the storage location adjacent the respective conveyor as said second address when activated.
4. The automated storage and retrieval system of Claim 3 wherein said control means further includes input means for designating said second address when said first control switch is activated and said first address when said second control switch is activated.
5. The automated storage and retrieval system of Claim 3 wherein said plurality of status lights associated with each conveyor are oriented on said control panel in a substantially aligned arrangement.
6. The automated storage and retrieval system of Claim 5 wherein said plurality of status lights associated with each conveyor are aligned on said control panel with said first and second control switches for said conveyor.

7. In an automated storage and retrieval system including a storage area comprising at least first and second parallel rows of storage racks each having a plurality of storage locations, a processing area having a plurality of
Claim 7...continued.
conveyors located adjacent storage locations in said first row of storage racks, transfer means operatively associated with each of said coneyors for transferring material from said adjacent storage locations onto said conveyors and from said conveyors into said adjacent storage locations, and a storage and retrieval machine adapted to travel along the aisle defined between said first and second rows of storage racks and retrieve material from a first location in said storage racks and deposit said load in a second location in said storage racks, the improvement comprising:
control means for controlling the operation of said storage and retrieval machine in accordance with a first address which designates the location in said storage racks where said storage/retrieval machine is to proceed to retrieve a desired load of material and a second address which designates the location in said storage racks where said storage/retrieval machine is to proceed to deposit said desired load of material, including a control panel having first and second control switches associated with each single conveyor, said first con-trol switch being operative to designate the location of the storage location adjacent the respective conveyor as said first address when activated and said second control switch being operative to designate the location of the storage location adjacent the respective conveyor as said second address when activated, and input means for designating said second address when said first control switch is activated and said first address when said second control is activated.
CA309,118A 1977-08-17 1978-08-10 Automated storage and retrieval system Expired CA1105849A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US82528477A 1977-08-17 1977-08-17
US825,284 1977-08-17

Publications (1)

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CA1105849A true CA1105849A (en) 1981-07-28

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Application Number Title Priority Date Filing Date
CA309,118A Expired CA1105849A (en) 1977-08-17 1978-08-10 Automated storage and retrieval system

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CA (1) CA1105849A (en)

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5924041B2 (en) * 1975-01-28 1984-06-06 ダイフクキコウ カブシキガイシヤ Luggage storage/unloading equipment

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