WO2004072879A1

WO2004072879A1 - Method of managing stocks of articles

Info

Publication number: WO2004072879A1
Application number: PCT/IB2004/000293
Authority: WO
Inventors: Thomas DÜRBAUM; Achim Hilgers; Roger Steadman
Original assignee: Philips Intellectual Property & Standards Gmbh; Koninklijke Philips Electronics N. V.
Priority date: 2003-02-14
Filing date: 2004-01-29
Publication date: 2004-08-26

Abstract

The invention relates to a method of managing stocks of articles (3a, 3b, 3c) wherein radio-frequency transponders (1a, 1b, 1c) are fastened to the articles as identity tags. Checking units (2a, 2b, 2c) at the compartments (A, B, C) in shelving (8) are able to exchange wireless signals with the articles to allow the presence of the latter in the appropriate compartment to be checked for. By making a comparison with a list of permitted articles, the placing of an article (3a) in the wrong compartment (A) can be detected and prevented. It is also possible for articles which are being looked for to be located with the system, which is done by having an interrogator (5) transmit the identity code of the associated transponder (1b), by having the appropriate transponder react with a response signal and by having the response signal received and indicated by the checking unit (2b) at the associated storage compartment (B).

Description

Method of managing stocks of articles

The invention relates to a system and a method for managing stocks of articles with the help of identifying tags.

The management of a delivery warehouse for a range of products is known from WO 02/17537. Information on the products held in store, including their storage locations in racks, is stored and managed by means of a database in this Case. On receipt of an order for a product, its presence in the warehouse and, if required, its storage location can be called up from this database. Via identity tags (RF tags) attached to the products that are capable of exchanging radio-frequency signals, the products can then be more accurately located at the given storage location by means of a portable RF scanner. One of the main things on which this system relies for its operation is that the products are always at the correct storage locations (rack compartments), because if they are not there will be a disagreement between the database and the actual whereabouts of the products. The system is therefore not suitable for use in a self-service operation such as, for example, a business selling garments because in businesses like this customers pick out products and constantly fail to put them back in the correct place.

Against this background, it was an object of the present invention to provide a method and system for managing stocks of articles, which method and system are suitable for use in self-service operations such as, for example, businesses selling garments.

This object is achieved by a method having the features given in claim 1 and by a system having the features given in claim 11. Advantageous embodiments are detailed in the dependent claims.

The method according to the invention for managing stocks of articles such as, for example, textile goods in a business selling garments comprises the following steps: - an identity tag (referred to below as an "ID tag" for short), which is arranged for the exchange of wireless communication signals in which an identity code that unambiguously identifies the ID tag is passed on, is fastened to each of the articles to be managed. The ID tags may in particular be radio-frequency (RF) transponders; - arranged in a fixed position at each of the preset storage locations for the articles, such as, for example, on shelves, drawers, garment rails and the like, are checking units, the checking units being arranged to perform the following steps;

- the checking units exchange wireless communication signals with the ID tags situated at the storage locations to allow the presence of ID tags at the storage locations to be checked;

- depending on the result of the above-mentioned check on the presence of ID tags, the checking units generate a notification signal. The notification signal may in particular be a visual signal such as the lighting of a light-emitting diode and/or an audio signal such as, say, a warning sound or a spoken output. The notification signal may also be an indication on a display and/or a report to a central unit.

The method explained above is a simple way of enabling stocks of articles to be managed in which all the actions required are each performed locally at the storage locations and are based only on verified measurement data. From the various embodiments of the method that are described below it will be seen how advantageous the management is that a method of this kind makes possible.

In a first improvement of the method, the checking units generate a notification signal when the identity code of an ID tag that is found to be present meets a criterion with respect to a preset list of identity codes. In particular, a notification signal may be generated when the identity code found is not shown on the preset list. When this is the case, the list represents a positive enumeration of articles that are rightly storable at the checking unit's storage location, and the notification signal indicates that an incorrect article has been deposited at the storage location. In a vending department for example, this makes it possible to detect that an item a customer has picked out has been put back in the wrong place. The customer's attention can be drawn to this mistake by the notification signal that the checking unit then generates and he can be caused to put the item in the correct place. An equivalent result can of course also be achieved by keeping a negative list that shows articles that are not permitted at the storage location, a notification signal being triggered if an article that appears on this list is detected.

The above-mentioned list may be stored in the checking unit. This is a useful course to adopt if, for example, the checking unit, which is mounted in a fixed position at the storage location, is to monitor unvarying use of the storage location for certain articles.

The checking units preferably determine all the ID tags present at the storage location at which they are mounted at preset intervals (which are, for example, equal in size or randomly distributed). In this way, the storage location is continuously monitored, thus enabling the presence or - if the intervals between checks are suitably short - even the entry of an article to be detected.

In another embodiment of the method, the list that is checked for a criterion in the variant of the method described above, may also be transmitted to the checking unit by wireless means from a separate interrogator. A procedure of this kind is a useful one to adopt when the contents of the list to be checked often change as a result of the changing situation. In particular, the list may in this case comprise a single identity code for a given article that is being looked for, thus enabling a transmission of the list to all the checking units to be used to make a search for the article concerned with the help of all the checking units. In this connection, it is also advantageous if, in response to outside instructions, which may, for example, come from the above-mentioned interrogator, the checking units determine all the ID tags that are present at their individual storage locations. By a step of this kind combined with the above-mentioned transmission of a search list, it is possible to find the whereabouts of a given article in the stock. In this case, the interrogator first transmits the search list giving the identity code of the article being looked for to the checking units and these then interrogate all the ID tags present in the region of their storage locations and, by a comparison with the search list, establish whether or not the article being looked for is present there. If a control unit finds the article being looked for to be present, it can indicate this by an appropriate notification signal. A method of this kind is therefore suitable for the swift location, within a space, of articles whose whereabouts are unknown. An alternative implementation of a method of searching of this kind is possible if, in response to outside instructions, which may for example come from the above- mentioned interrogator, the ID tags emit a response signal that includes the identity code of the individual ID tag. By using suitable facilities such as, say, directional antennas, the response signal can then be received at a central point (e.g. by the interrogator) and used to locate the ID tag emitting it. Because the ID tag transmitted its identity code as well, any article that is being specifically looked for can be located in this way. However, rather than by a central unit, the response signals from the ID tags may also be received and evaluated only by the control units mounted at the given storage locations. If, in association with an embodiment of the method as mentioned above, the checking units have previously had transmitted to them by the interrogator a search list of identity codes, they can compare the identity codes emitted by the ID tags with this list and, if they find the identity code of an ID tag in the list, can generate a notification signal to this effect, The outside instructions may also come from a checking unit, in which case the ID tag responds to them if it is not assigned to the checking unit concerned, i.e. has been put in the wrong place.

Another variant of the method of searching can be implemented by causing the ID marks to emit a response signal, in reply to an identity code that is being looked for being transmitted from outside, if the identity code being looked for matches the ID tag's own identity code. Also, in this method, a checking unit mounted at the storage location of the ID tag preferably establishes from receipt of the response signal that the ID tag is present at the storage location, whereupon it can generate an appropriate notification signal. When this is the case, the checking units therefore do not need to know the identity code being looked for because it is automatically only ID tags that have this code that report themselves present. There are various possible ways of establishing whether or not an ID tag is present at the storage location assigned to a checking unit. In the simplest case, the very design of the storage locations and the range of the communication signals are such that the communication signals emitted by the LD tags only reach the checking unit mounted at the given storage location, and vice versa. If, however, the communication signals emitted by the ID tags are able to reach more than one checking unit, location of the ID tags is preferably performed, on the basis of the strength of the signals. A certain minimum signal strength may, for example, be laid down that has to be exceeded if a checking unit is to consider the emitting ID tag present at its associated storage location. The checking units may also measure the signal strength of the communications signals emitted by an ID tag at different, distributed points and determine the position of the ID tag by comparing these measurements. hi this case, a local maximum of signal strength may be considered to indicate the whereabouts of the ID tag. If the checking units are coupled together, they can compare the strengths of the communications signals respectively received by them, and the checking unit whose value for the measured signal strength is highest specifies that the ID tag is situated at its associated storage location. The position found for the ID tag is preferably then indicated.

In a further embodiment of the method, the checking units are coupled to a central data-processing unit and the data-processing unit keeps a list of stockholdings. Because of the coupling to a central data-processing unit, the items of information on the presence of the articles held in stock come together centrally at one point, which means that they can be analyzed there in any desired fashion. The data-processing unit may also assume responsibility for various functions performed by the checking units, such as comparing identity codes picked up by the checking units with preset lists, emitting visual and/or audio notification signals, and the like. The invention further relates to a system for managing stocks of articles, which system comprises a plurality of ID tags, and in particular radio-frequency transponders, to be fastened to the articles and a plurality of checking units to be arranged at the storage locations for the articles. The system is arranged to carry out a method of the kind explained above. What this means is that the checking units are able to exchange wireless communication signals with the ID tags to check for the presence of ID tags at the storage location and that they are able to generate a notification signal as a function of this check. By means of appropriate additions to the system, for example by means of visual and/or audio indicator devices, by means of an interrogator and/or by means of a central data-processing unit, the system may also be so arranged that all the variants of the stated method may be carried out.

These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.

In the drawing:

Fig. 1 is a diagrammatic view showing the use of the method according to the invention to manage a vending space in a business selling garments.

Shown in the Figure are three compartments A, B, C in vending shelving 8 which act as storage locations for articles 3a, 3b, 3c such as, for example, trousers or pullovers of different sizes. To enable the customer to find a given article, such as, say, a pair of trousers of his size, quickly under the self-service system, the articles have to be sorted into the storage locations in the shelving 8 in a preset order. However, because of the frequent access by customers to the articles, to try on a pair of trousers for example, and the subsequent failure to put them back in the right place, the sorting system can easily be disrupted, thus making it impossible for a subsequent customer to find a desired product or allowing him to find it only after a long search. To avoid this problem, it is proposed in accordance with the invention that identity tags (ID tags) la, lb and lc are respectively attached to all the articles 3a, 3b, 3c. The ID tags may, for example, be radio-frequency transponders that have individual identity codes and are arranged to transmit and receive radio-frequency signals. The compartments in the shelving are also fitted with respective checking units 2a, 2b, 2c which may, for example, be housed in the shelves forming the floors of the compartments. The checking units 2a, 2b, 2c are arranged to exchange signals with the transponders la, lb, lc. Given these prerequisites, the various variant methods that are explained in detail below can be performed to manage the stock of articles 3a, 3b, 3c.

In a first variant of the method, a checking unit 2a transmits an enquiry for the identity code of an article 3a when the latter is first placed in the appropriate compartment A of the shelving. For this purpose, a monitoring system such as, for example, a light barrier may be provided which detects the entry of article 3a into compartment A. Alternatively however, the checking unit 2a may also query the identity codes of all the articles situated within its transmitting range, thus enabling an article 3 a that is just entering compartment A also to be detected.

In response to the enquiry by the checking unit 2a, the ID tag la on article 3a transmits the associated identity code to the checking unit 2a. The latter can then compare the code with an internally stored list that contains the identity codes of the articles that are permitted in compartment A. If the identity code transmitted is not found in this list, the checking unit emits an appropriate audio or visual notification signal. A light-emitting diode 4 connected to the checking unit 2a may, for example, be caused to light.

The checking unit 2a is also coupled by a line 7 to a central data-processing unit 6 in which the information on the article 3a that has been wrongly placed in compartment A can be stored. At the close of business, an employee can then return the articles 3 a that have been put in the wrong places to their correct locations in the shelving by referring to the list kept by the computer 6. This being the case, the customer would not be irritated by the notification signal from the checking unit. The computer, when in a sorting mode, could indicate compartments containing wrongly sorted articles sequentially (e.g. from top right to bottom left), compartment by compartment. An indicator (e.g. a red LED) on a compartment currently being considered could be switched on in this case until such time as all the wrong articles had been withdrawn from it.

As an alternative to picking out a compartment by, for example, an LED 4, the storage location may also be shown to the user in some other way if there is a coupling to the computer 6, e.g. by showing it on a portable display-equipped computer (a handheld). In another embodiment of the above system, the system may assist the employee in sorting articles into their correct positions. For this purpose, the system has to be set to a sorting mode in which, for example by presetting an identity code or a type of product at the computer 6, the checking unit situated at the correct associated storage compartment is activated and then indicates its position via an LED 4. Alternatively, the compartment in the correct position could also be shown on the display of the computer 6 or the employee could be guided to the correct compartment by a spoken output. Also, in the sorting mode, compartments containing articles in the wrong places may be indicated by the central unit on a handheld, thus enabling the employee to find the sequence for sorting for himself. To enable the articles in a compartment that are in the wrong place to be found, the employee could bring the articles in the compartment close to his handheld one after the other, to initiate an enquiry that will display the correct compartment on the display and/or will activate an indicator, such as a green LED for example, on the correct compartment. Finally, the articles that are in the wrong place may also be found by the employee first emptying the compartment and then replacing the articles one at a time, in which case the "alarm" described above will be triggered by a wrong article being put in. By gating the checking units 2a, 2b, 2c together or to a computer 6, it can also be ensured that, when an article 3 a is placed in the wrong compartment A, it is on the one hand indicated by a warning signal such as, for example, a red LED on compartment A, that compartment A is the wrong storage location. At the same time, the system could, by reference to article 3a's identity code, determine which is the correct storage location and activate an appropriate indication there, such as a green LED, for example.

What is more, the system shown in the Figure also enables an article that is being looked for to be located efficiently. In this case, radio-frequency signals that contain in particular the identity code of an article 3b or 3c that is being looked for are broadcast into the entire space, by an interrogator 5, for example. In a first variant of the method of location, all the ID tags la, lb, lc receive the signals from the interrogator 5 and compare the identity code contained in them with their own identity code. Only the identity tag lb that finds a match between the identity codes then emits a response signal. If this signal is strong enough, it could, for example with the help of directional antennas set up in the vending space, be used as a direct indication of the position of the article 3b being looked for. Preferably however, the article 3b is located with the help of the checking unit 2b situated at compartment B of the shelving. This checking unit receives the response signal from ID tag lb at close range and thus at relatively high strength, and is thus able to react to the reception of this signal by emitting a notification signal, for example by activating an LED. If, for example, it is desired for the article 3b in compartment B to be more exactly located or if, for example, a checking unit (such as checking unit 2a) in a compartment other than the correct one is to be prevented from being activated by the response signal from an article 3b, recourse is preferably had to an evaluation of the strength of the response signal. The response signal may, for example, be evaluated as coming from the correct compartment only if its strength exceeds a certain minimum level. Also, antennas may be fitted in the shelf forming the floor of the compartment by means of which it is possible to determine the position at which the received strength of the response signal is highest, and hence the position of the article 3b being looked for. What is more, the inter- coupled checking units 2a, 2b, 2c may also compare the individual received strengths of the response signal, in which case the presumption will be that the article being looked for is in the compartment of the checking unit that receives the strongest signal.

In another variant of the method of location, the checking units 2a, 2b, 2c too receive the communication signals from the interrogator 5 and determine the identity code that is being looked for that is contained in them. Also, all the ID tags la, lb, lc may, in response to receiving the communication signals from the interrogator 5, emit communication signals that contain the particular identity codes of the ID tags. Knowing the identity code being looked for which it has received beforehand, each checking unit 2a, 2b, 2c can then determine whether or not the article 3b being looked for is in its associated compartment. If it finds that it is, it may react as described above by for example activating an LED associated with the compartment.

Alternatively, even after receiving the communication signals from the interrogator 5, the checking units 2a, 2b, 2c may in turn query the identity codes of the articles stored in their respective compartments. If when they do so they find the article being looked for to be present, they can indicate this finding in the appropriate way as described above. List of reference numerals

la, lb, lc Identity tags

2a, 2b, 2c Checking units

3a, 3b, 3c Articles

4 Light-emitting diode (LED)

5 Interrogator

6 Data-processing unit

7 Connecting line

8 Shelving

Claims

CLAIMS:

1. A method of managing stocks of articles (3 a, 3b, 3 c), wherein

- each of the articles has fastened to it an identity tag (la, lb, lc) that is arranged for the exchange of wireless communication signals in which an identity code is passed on;

- respective checking units (2a, 2b, 2c) are arranged in fixed positions at preset storage locations (A, B, C) for the articles;

- the checking units (2a, 2b, 2c) exchange wireless communication signals with the identity tags (la, lb, lc) situated at the storage locations in order to check for the presence of identity tags (la, lc) at the storage locations;

- the checking units (2a, 2b, 2c) generate a notification signal as a function of the check for the presence of identity tags .

2. A method as claimed in claim 1, characterized in that the notification signal is a visual and or audio signal.

3. A method as claimed in claim 1, characterized in that the checking units (2a,

2b, 2c) generate a notification signal if the identity code of an identity tag (la) that is found to be present meets a criterion in respect of a preset list of identity codes.

4. A method as claimed in claim 3, characterized in that the list is stored in the checking unit (2a, 2b, 2c).

5. A method as claimed in claim 1, characterized in that the checking units (2a, 2b, 2c) determine all the identity tags (la, lb, lc) that are present at their respective storage locations (A, B, C) at preset intervals and/or in response to outside instructions.

6. A method as claimed in claim 3, characterized in that the list is transmitted to the checking unit (2c) from an interrogator (5) by wireless means.

7. A method as claimed in claim 1, characterized in that the identity tags (lb) emit their identity codes in response to outside instructions.

8. A method as claimed in claim 1, characterized in that an identity tag (lb) emits an identity code that is being looked for, in response to outside instructions, if the identity code that is being looked for matches its own identity code

9. A method as claimed in claim 1, characterized in that the checking units (2a, 2b, 2c) determine whether an identity tag (la, lb, lc) is present at a storage location (A, B, C) by measuring and comparing the strengths, as they exist at different points, of the communication signals emitted by the identity tag.

10. A method as claimed in claim 9, characterized in that the whereabouts found for the identity tags (la, lb, lc) is indicated.

11. A method as claimed in claim 1, characterized in that the checking units (2a, 2b, 2c) are coupled to a central data-processing unit and in that the data-processing unit keeps a list of stocl holdings.

12. A system for managing stocks of articles (3a, 3b, 3c) comprising a plurality of identity tags (la, lb, lc) to be fastened to the articles and a plurality of checking units (2a, 2b, 2c) to be arranged at storage locations for the articles, wherein the system is arranged to carry out a method as claimed in any of claims 1 to 11.