System for taking an inventory of objects contained in a space bounded by a chamber

Abstract

The invention relates to a system for taking an inventory of objects contained in a closed space delineated by a chamber, comprising at least one circuit board, the circuit board comprising: - a plurality of sensors (Cap1, Cap2, CapN), each sensor consisting of an electronic circuit made up of an inductor and capacitor, - means (200) for activating measurements (701, 702) of at least one characteristic of at least one set of electronic circuits made up of an inductor and capacitor, - means (200) for activating a comparison of each measured characteristic with a determined reference characteristic, - means (200) for activating a determination of the presence of an object depending on at least one comparison result.

Description

[0001] INVENTORY SYSTEM FOR OBJECTS CONTAINED IN A LIMITED SPACE

[0002] BY A SPEAKER

[0003] TECHNICAL FIELD

[0004] The present invention relates to a system for inventorying objects contained in a space limited by an enclosure using eddy current technology as well as an inventory method implemented by such an inventory system.

[0005] STATE OF PRIOR ART

[0006] Inventory systems for objects contained in a limited space using RFID technology are known. Generally speaking, a system using RFID technology consists of three types of elements:

[0007] - at least one transponder, also called a tag, consisting of an electronic circuit provided with an antenna for transmitting and receiving data in the form of radiofrequency waves, the circuit comprising at least one memory in which an identifier of said transponder is stored,

[0008] - a reading point also consisting of an electronic circuit equipped with an antenna for transmitting and receiving data also in the form of radiofrequency waves, and

[0009] - a control unit connected to the reading point and implementing an application. The operation of such an RFID system is as follows. At the beginning of the identification procedure, the reading point emits a modulated electromagnetic wave, subsequently called a wake-up wave, to each tag in the system. Upon receipt, a tag, located in a coverage area where the electromagnetic field generated by the reading point is at a sufficiently high level, is electrically powered by the electromagnetic wave, comes out of its standby state, becomes active and then emits identification data specific to it in the form of a modulated electromagnetic wave. This identification data is received by the reading point which then proceeds to identify the tag in question.

[0010] REPLACEMENT SHEET (RULE 26) In the application to an inventory system envisaged here, each tag is attached to an object, such as a tool used for the maintenance of a workshop, a factory, etc. The objects to be inventoried are stored in an enclosed space, such as a piece of furniture, a trolley, a cupboard. This enclosed space is subdivided into a plurality of enclosed sub-spaces such as, for example, shelves, drawers, etc.

[0011] Objects that do not have a large enough surface area to which a tag can be attached, or tools that do not have an unused / uncurved surface, or objects whose tag does not allow good detection reliability, cannot be inventoried with an RFID system. For example, in an industrial environment, such objects are sockets, screwdriver bits, Allen keys, universal joints.

[0012] The present invention aims to resolve the drawbacks of the prior art by proposing a method and a system for inventorying in an enclosed space delimited by an enclosure objects which do not have a sufficiently large surface to which a tag can be fixed, or objects which do not have an unused / uncurved surface, or objects whose tag does not allow good reliability of detection contained in an enclosed space delimited by an enclosure.

[0013] STATEMENT OF THE INVENTION

[0014] To this end, the invention relates to a method for inventorying objects contained in an enclosed space delimited by an enclosure, the enclosed space comprising at least one enclosed sub-space, the at least one enclosed sub-space comprising an electronic card on which is placed a support comprising recesses for receiving objects to be inventoried comprising at least one metal part, at least one part of the recesses being shaped to receive respectively one object, the system comprising a control device capable of determining whether all the objects are included in the enclosed space, characterized in that the electronic card comprises a plurality of sensors, each sensor consisting of an electronic circuit composed of an inductor and a capacitor and in that the method comprises the steps, executed by a microcontroller of the electronic card, of:

[0015] - receiving a command from the control device to carry out measurements, - activating measurements of at least one characteristic of at least one set of electronic circuits composed of an inductor and a capacitor,

[0016] -activation of a comparison of each measured characteristic with a reference characteristic determined for each electronic circuit composed of an inductor and a capacitor,

[0017] - activation of a determination of the presence of an object based on at least one comparison result,

[0018] - transfer to the control device of a frame comprising, for each electronic circuit of the set of electronic circuits composed of an inductor and an active sensor capacitor, information representative of the detection or not of the presence of small objects.

[0019] The invention also relates to a system for inventorying objects contained in an enclosed space delimited by an enclosure, the enclosed space comprising at least one enclosed sub-space, the at least one enclosed sub-space comprising an electronic card on which is placed a support comprising recesses for receiving objects to be inventoried comprising at least one metal part, at least one part of the recesses being shaped to receive respectively one object, the system comprising a control device capable of determining whether all the objects are included in the enclosed space, characterized in that the electronic card comprises a plurality of sensors, each sensor consisting of an electronic circuit composed of an inductor and a capacitor, and in that the electronic card further comprises:

[0020] - means for receiving a command from the control device to carry out measurements,

[0021] - means for activating measurements of at least one characteristic of at least one set of electronic circuits composed of an inductor and a capacitor,

[0022] - means for activating a comparison of each measured characteristic with a reference characteristic determined for each electronic circuit composed of an inductor and a capacitor,

[0023] - means for activating a determination of the presence of an object based on at least one comparison result, - means for transferring to the control device a frame comprising, for each electronic circuit of the set of electronic circuits composed of an inductor and an active sensor capacitor, information representative of the detection or not of the presence of small objects.

[0024] Thus, it is possible to carry out an inventory of objects which do not have a large enough surface on which a tag can be fixed, or of objects which do not have an unused / uncurved surface, or of objects whose tag does not allow good detection reliability.

[0025] According to a particular mode, each sensor is respectively arranged on the electronic card at an intersection of a horizontal line and a vertical line, the vertical and horizontal lines being regularly spaced.

[0026] Thus, the present invention makes it possible to carry out an inventory on a large number of objects without the need for sensors adapted to the size of the object to be inventoried. Great flexibility in positioning the tools is allowed, while being modular for a controlled cost.

[0027] According to a particular mode, the system includes:

[0028] - means for measuring the temperature in the enclosed subspace, the reference characteristic determined for each electronic circuit composed of an inductor and a capacitor being obtained from a measurement of the characteristic when the support comprising recesses is empty,

[0029] - means for storing the temperature measured during the measurement of the characteristic when the support comprising recesses is empty and the measurement of the characteristic when the support comprising recesses is empty.

[0030] According to a particular mode, the temperature of the enclosed subspace is measured when measuring the characteristic of at least part of the electronic circuits composed of an inductor and a capacitor, the reference characteristic being determined according to the following formula:

[0031] Zcomp = Zref * (1 + (Tact - Tref) * Tcoefft) where Tcoefft is a previously stored configuration variable, Zref is the measurement of the characteristic when the support with recesses is empty, Tref is the temperature measured when measuring the characteristic when the support with recesses is empty and Tact is the temperature measured when the means of measuring the characteristic are activated.

[0032] This makes it possible to ensure accurate measurement allowing operation with a low tolerance (Toi) essential for object differentiation and tracking of very small objects, regardless of the temperature variation of the system's environment. In addition, this accurate measurement allows the detection of a non-metallized object but which has a metallic coating.

[0033] According to a particular embodiment, the control device is connected to a UHF RFID reader placed in the enclosed space, the UHF RFID reader is provided with at least one antenna (not shown) which emits electromagnetic waves to RFID tags. Thus, it is possible to ensure the tracking in the same enclosed space of small tool objects and larger objects provided with RFID tags.

[0034] Depending on a particular mode, the characteristic is a parallel impedance and / or a frequency.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above-mentioned and other features of the invention will become more clearly apparent from the following description of exemplary embodiments, said description being made in relation to the attached drawings, among which:

[0037] [Fig. 1] is a schematic view of a maid inventory system in which the present invention is implemented;

[0038] [Fig. 2] is an example architecture of the inventory system according to the present invention;

[0039] [Fig. 3] is an example of a holder having recesses for receiving objects to be inventoried according to the present invention;

[0040] [Fig. 4] is an example of an architecture of a microcontroller capable of managing the operation of sensors to carry out an inventory of objects in an enclosed sub-space; [Fig. 5] is an example of a sensor matrix for determining the presence or absence of objects to be inventoried according to the present invention;

[0041] [Fig. 6] is a view explaining the principle of eddy current detection of an object;

[0042] [Fig. 7] is an example of the architecture of an electronic card included in the enclosed space;

[0043] [Fig. 8] represents an example of an algorithm executed by a microcontroller of the electronic card included in the enclosed space according to the present invention.

[0044] DETAILED PRESENTATION OF IMPLEMENTATION METHODS

[0045] Fig. 1 is a schematic view of an inventory system according to a first embodiment of the present invention.

[0046] The inventory system shown in Fig. 1 is intended to inventory objects which are contained in an enclosed space such as a piece of furniture 10, a cabinet or a workshop trolley, which may contain elements such as shelves, drawers Tir forming enclosed sub-spaces. This enclosed space and these enclosed sub-spaces are respectively delimited by a metal enclosure.

[0047] The objects in question are, for example, tools for maintaining a workshop, a factory, etc. Some of these objects are equipped with an RFID tag (Radio Frequency IDentification) while others, due to their small size, do not have an RFID tag.

[0048] Objects without an RFID tag will subsequently be called small objects.

[0049] The inventory system includes a control device 100.

[0050] Fig. 2 is an exemplary architecture of the inventory system according to the present invention.

[0051] The control device 100 is connected to a UHF RFID reader 250 arranged on the enclosed space 10. The UHF RFID reader 250 is provided with at least one antenna (not shown) which emits electromagnetic waves to RFID tags. The control device 100 is, for example, a computer, a smartphone, a touchscreen tablet. According to the invention, the control device 100 is capable of generating requests to at least one microcontroller 200 of an electronic card included in an enclosed sub-space to activate detection of the presence or absence of at least one small object in the enclosed sub-space in which the electronic card is placed.

[0052] Requests and responses from at least one electronic card are transmitted via a wired or radio COM link.

[0053] For example, a first electronic card Cal is arranged in a first enclosed sub-space and a second electronic card Ca2 is arranged in a first enclosed sub-space. Each electronic card comprises a microcontroller 200.

[0054] The control device 100 has a database comprising the objects stored in the enclosed space. The control device 100 executes a control program and decides on the presence or absence of all objects, either tagged tools or small objects.

[0055] In order to configure the number of supports comprising recesses, the number of electronic cards, and in order to associate the location of the tools with the detector(s), the control device 100 interrogates each electronic card which, in response, transmits its unique identifier to it, the control device 100 establishes a list of electronic cards and associates with each small object the identifier of the electronic card and each position of the sensor(s) to which the small object must be facing.

[0056] The control device 100 notifies each electronic card of the list of sensors to be used by the electronic card and each electronic card records the at least one characteristic of the resonant circuit of each sensor to be used when the support having recesses is empty and the temperature at which the measurement is made. Fig. 3 is an example of a support having recesses for receiving objects to be inventoried according to the present invention.

[0057] The Mou support has recesses Orl, Or2, Or3 and Or4 to receive objects to be inventoried.

[0058] The Soft support is for example a polymer foam. The Orl recess is shaped to receive the objects 01, 02 and 03. The Or2 and Or4 recesses are shaped to receive a single object respectively.

[0059] The recess Or3 is shaped to receive a single object 04.

[0060] In the example of Fig. 3, objects 01, 02, 03 and 04 are respectively present in the recess allocated to them. The recesses are adapted to match the shape of the object or are adapted to receive several objects.

[0061] No objects are present in recesses Or2 and Or3.

[0062] Fig. 4 is an example of the architecture of a microcontroller capable of managing the operation of sensors to carry out an inventory of objects in an enclosed subspace.

[0063] The microcontroller according to the present invention comprises:

[0064] - a processor, microprocessor, or microcontroller 400;

[0065] - a volatile memory 403;

[0066] - a non-volatile memory 402;

[0067] - an I / F interface for controlling the electronic card 404;

[0068] - a bidirectional COM 405 communication interface;

[0069] - a communication bus connecting the processor 400 to the ROM memory 402, to the RAM memory 403, to the IF interface 404 and to the COM communication interface 405. The processor 400 is capable of executing instructions loaded into the volatile memory 403 from the non-volatile memory 402, from an external memory (not shown), from a storage medium, such as an SD card or the like, or from a communication network. When the controller 200 according to the present invention is powered up, the processor 400 is capable of reading instructions from the volatile memory 403 and executing them. These instructions form a computer program which causes the processor 400 to implement all or part of the method described in relation to Fig. 8.

[0070] All or part of the method described in relation to Fig. 8 may be implemented in software form by executing a set of instructions by a programmable machine, such as a DSP (Digital Signal Processor in English or Digital Signal Processing Unit in French) or a microcontroller or be implemented in hardware form by a machine or a dedicated component, such as an FPGA (Field-Programmable Gate Array in English or Field-Programmable Gate Array in French) or an ASIC (Application-Specific Integrated Circuit in English or Application-Specific Integrated Circuit in French).

[0071] Fig. 5 is an example of a sensor array for determining the presence or absence of objects to be inventoried according to the present invention.

[0072] At least one sensor array is arranged on each circuit board. In the example in Fig. 5, the sensor array is on the Cal circuit board.

[0073] The sensor matrix comprises a plurality of sensors denoted Capl to CapN arranged regularly on the surface of the electronic card Cal.

[0074] The Cal electronic card is placed below the Mou support located in the Tir drawer.

[0075] The sensors are arranged at the intersections of regularly spaced horizontal and vertical lines. For example, the horizontal and vertical lines are spaced 3 cm apart.

[0076] This architecture allows the creation of electronic cards suitable for any type of small object.

[0077] Depending on the size of the object and its intended location in the Soft support, one or more sensors can be located opposite said small object.

[0078] Fig. 6 is a view explaining the principle of eddy current detection of an object.

[0079] A sensor, for example the sensor Capl, consists of an inductor L1 and a capacitor Cl forming a resonant circuit. The presence of a small object such as the object O1 increases the effective inductance of the resonant circuit and therefore reduces the oscillation frequency. Instead of, or in addition to, the detection is carried out by measuring the change in the characteristic. The microcontroller can measure the frequency, and make the comparison between the measured frequency and the reference frequency when the recess is empty. The difference between the values ​​determines whether the tool is present or not. It is possible to fool the detection by putting another metal object in the recess. According to the invention, the microcontroller 200 learns two reference values: when the recess is empty and when the small object intended to be placed in the recess is present.The microcontroller 200 can then differentiate between an empty recess, the small object placed in the recess and another small object according to the value of the impedance and / or the frequency measured. For a small object which is arranged opposite several sensors, its presence can be characterized by several reference values ​​for each sensor.

[0080] The small object must be a metallic conductive object, ferrous or not. The small object may be partially or completely covered with a metallic coating.

[0081] Fig. 7 is an example of the architecture of an electronic board included in the enclosed space.

[0082] Each electronic card includes a microcontroller 200, N sensors Capl to CapN, each sensor Capi, with i=l to N is made up of an inductance Li and a capacitor Ci. The sensors Capi are connected to a multiplexer made up of switches SW 1 to SWN and SW' 1 to SW'N. Each electronic card includes a module for measuring the parallel impedance 701 of each sensor, a module for measuring the resonant frequency 702 of each sensor, an oscillator circuit 703 and a temperature sensor 704.

[0083] Fig. 8 represents an example of an algorithm executed by a microcontroller of the electronic card included in the enclosed space according to the present invention.

[0084] In step E800, the microcontroller 200 detects the reception of a message from the control device 100 requesting to carry out a check of the impedance and / or the frequency of the sensors Capi to CapN.

[0085] In step E801, the microcontroller 200 selects an active sensor, for example the CAI sensor, by positioning the switches SW1 and SW' 1 in the closed position. In step E802, the microcontroller obtains a measurement of the impedance and / or the frequency of the Capi sensor.

[0086] The sensor resistance, and therefore the measured characteristic, varies depending on the temperature of the circuit board. In order to prevent erroneous detection when a recess is empty, or to avoid an error, temperature compensation is performed.

[0087] During the configuration process, for each sensor Capl to CapN, the microcontroller measures the characteristic (Zref) and stores it in the non-volatile memory. At the same time, it measures the reference temperature (Tref) and stores it in the non-volatile memory.

[0088] By performing the inventory, for each sensor, the microcontroller obtains a measurement of the characteristic (Zact) and obtains a measurement of the temperature (Tact).

[0089] In step E803, the microcontroller calculates the compensated reference characteristic (Zcomp), using the equation:

[0090] Zcomp = Zref * (1 + (Tact - Tref) * Tcoefft) where Tcoefft is a configuration variable stored in non-volatile memory. Its value is the result of a series of tests across the operational temperature range.

[0091] A small object is determined to be present if:

[0092] Zact > Zcomp + Toi where Toi is a configuration variable stored in non-volatile memory. Its value is the result of a series of tests that determine the sensitivity of the detection of the smallest objects.

[0093] In step E804, the microcontroller 200 checks whether all active sensors have been measured.

[0094] If so, the microcontroller 200 goes to step E806; if not, the microcontroller 200 goes to step E805, selects another sensor and returns to step E801.

[0095] In step E806, the microcontroller 200 controls the transfer of a frame comprising, for each active sensor, information representative of the detection or not of the presence of small objects.

Claims

CLAIMS 1) System for inventorying objects contained in an enclosed space delimited by an enclosure, the enclosed space comprising at least one enclosed sub-space, the at least one enclosed sub-space comprising an electronic card on which is placed a support comprising recesses for receiving objects to be inventoried comprising at least one metallic part, at least one part of the recesses being shaped to receive respectively one object, the system comprising a control device capable of determining whether all the objects are included in the enclosed space, characterized in that the electronic card comprises a plurality of sensors (Capl, Cap2, CapN) using eddy current technology, each sensor consisting of an electronic circuit composed of an inductor and a capacitor, and in that the electronic card further comprises: - means (200) for receiving a command from the control device to carry out measurements, - means (200) for activating measurements (701, 702) of at least one characteristic of at least one set of electronic circuits composed of an inductor and a capacitor, - means (200) for activating a comparison of each measured characteristic with a reference characteristic determined for each electronic circuit composed of an inductor and a capacitor, - means for activating (200) a determination of the presence of an object based on at least one comparison result, - means for transferring (200) to the control device a frame comprising, for each electronic circuit of the set of electronic circuits composed of an inductor and a capacitor, information representative of the detection or not of the presence of small objects. 2) System according to claim 1, characterized in that each sensor is respectively arranged on the electronic card at an intersection of a line horizontal and a vertical line, the vertical and horizontal lines being spaced regularly. 3) System according to claim 2, characterized in that the system comprises: - means for measuring the temperature in the enclosed subspace, the reference characteristic determined for each electronic circuit composed of an inductor and a capacitor being obtained from a measurement of the characteristic when the support comprising recesses is empty, - means for storing the temperature measured during the measurement of the characteristic when the support comprising recesses is empty and the measurement of the characteristic when the support comprising recesses is empty. 4) System according to claim 3, characterized in that the temperature of the enclosed subspace is measured when measuring the characteristic of at least part of the electronic circuits composed of an inductor and a capacitor, the reference characteristic being determined according to the following formula: Zcomp = Zref * (1 + (Tact - Tref) * Tcoefft) where Tcoefft is a previously stored configuration variable, Zref is the measurement of the characteristic when the support with recesses is empty, Tref is the temperature measured when measuring the characteristic when the support with recesses is empty and Tact is the temperature measured when the means of measuring the characteristic are activated. 5) System according to any one of the preceding claims, characterized in that the control device 100 is connected to a UHF RFID reader arranged in the enclosed space. The UHF RFID reader is provided with at least one antenna which emits electromagnetic waves to RFID tags. 6) System according to any one of claims 1 to 5, characterized in that the characteristic is a parallel impedance and / or a frequency. 7) Method for inventorying objects contained in an enclosed space delimited by an enclosure, the enclosed space comprising at least one enclosed sub-space, the at least one enclosed sub-space comprising an electronic card on which is placed a support comprising recesses for receiving objects to be inventoried comprising at least one metallic part, at least one part of the recesses being shaped to receive respectively one object, the system comprising a control device capable of determining whether all the objects are included in the enclosed space, characterized in that the electronic card comprises a plurality of sensors using eddy current technology, each sensor consisting of an electronic circuit composed of an inductor and a capacitor, and in that the method comprises the steps, executed by a microcontroller of the electronic card, of: - receipt of a command from the control device to carry out measurements, - activation of measurements of at least one characteristic of at least one set of electronic circuits composed of an inductor and a capacitor, -activation of a comparison of each measured characteristic with a reference characteristic determined for each electronic circuit composed of an inductor and a capacitor, - activation of a determination of the presence of an object based on at least one comparison result, - transfer to the control device of a frame comprising, for each electronic circuit of the set of electronic circuits composed of an inductor and a capacitor, information representing the detection or not of the presence of small objects.

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