FR2678540A1 - Method and system for helping with the distribution and choice of components for assembling objects on an industrial assembly line - Google Patents

Abstract

The components are displayed in boxes (4) grouped together in a matrix configuration in a display stand (3). Each box (4) is associated with signalling means (15) for indicating to an operator that at least one component must be taken from this box (4), and boxes (4) are selected as a function of the components to be assembled. A central processing unit (25) manages the activation of the signalling means (15) relating to the selected boxes (4). The display stand (3) is made up by grouping together modular sub-sets of boxes (5) each comprising a local processing module which communicates with the central processing unit (25) in order to command the activation of the signalling means (15) relating to the selected boxes (4) belonging to this modular sub-set (5). Use for reducing the risk of error in the choice of components to be assembled.

Description

 The present invention relates to a method and a system for assisting with the distribution and choice of parts for assembling objects on an industrial assembly line.

 This type of system, located at the edge of an assembly line, usually includes a display cabinet, the front of which comprises a set of boxes in which the various parts to be assembled are placed, the supply of which is ensured by the rear side of the display. Depending on the object being assembled, the operator takes the necessary parts from the corresponding boxes.

 A difficulty encountered in these systems is that the high production rates and the increasing diversity involve significant risks of error in the choice of parts. The ergonomics of the display is an essential consideration to minimize these risks and lighten the compliance verification tasks performed at the end of the chain.

 When the chain is used to assemble different models of the same type of object (for example different models of a line of cars according to the engines, the options chosen ...), the operator often does not have the possibility, or time, to realize the errors of choice of parts. His attention is therefore strongly requested when he picks up the parts, which over time causes a certain fatigue, itself a source of errors or poor workmanship.

 A main object of the present invention is to provide a method and a system for assisting with the distribution and selection of parts which minimizes the risk of error in the choice of parts.

 Another object of the invention is to ensure that the method is particularly simple to implement and that the system can be easily installed on a wide variety of industrial sites.

Another object of the invention is still that the system is economical.

 According to a first object, the invention thus provides a method of assisting with the distribution and choice of parts for assembling objects on an industrial assembly line, the parts being presented in boxes grouped in a matrix in a display rack. , characterized in that each box is associated with signaling means to indicate to an operator that at least one part must be taken from this box and boxes are selected according to the parts to be assembled, in that a unit of central processing manages the activation of the signaling means relating to the selected boxes, and in what constitutes the display by grouping modular subsets of boxes each comprising a local processing module which communicates with the central processing unit to control the activation of the signaling means relating to the selected boxes belonging to this modular subset.

The signaling associated with the boxes being activated according to the parts to be removed for assembly, the risk of errors is reduced. It will be observed that the invention achieves this result by means of modular sub-assemblies each equipped with a local processing module, which ensures decentralization of "intelligence". It is therefore sufficient to pre-wire the modular sub-assemblies and, when forming the matrix facade by grouping them, to simply connect the local processing modules to the central processing unit. Compared to a solution which would consist in grouping the different signaling means to a central controller, the invention brings many advantages:
- reduced cost by simplifying wiring and processing circuits;
- ease of installation;
- possibility of extending or reducing the size of the matrix depending on the number of parts to be taken into account, by adding or removing modular sub-assemblies;
- possibility of reusing elsewhere modular subassemblies removed from an assembly station while retaining the signaling functions, which allows a better return on investment in equipment which is no longer devoted to a specific station.

 In addition, the central processing unit can be connected to a device for reading codes (optical codes, electronic labels or the like) carried by the objects on the assembly line to automatically select the boxes of the parts to be removed. Another possibility is to connect the central processing unit to the computer system supervising the entire assembly line.

 According to a preferred version of the method of the invention, the picking up of parts in the boxes of the matrix is detected by means of sensors mounted on the modular subassemblies, and the information obtained from these sensors is collected at the processing modules. local to send them to the central processing unit which monitors the detection of the picking of the parts in the selected boxes.

 We can thus validate the choices made by the operator, and detect any errors or omissions. Any error can be immediately reported to the operator so that he has the opportunity to correct it. Detecting the removal of parts also dissuades the operator from committing errors, whether voluntary or not, because he then knows that his responsibility would risk being called into question.

 Monitoring of parts samples is provided by the central processing unit, but the various detection information is transmitted by the local processing modules, in accordance with the modularity characteristic essential to the invention.

 A second object of the invention relates to a system for assisting with the distribution and choice of parts, for assembling objects on an industrial assembly line, comprising a display organized in a matrix of boxes in which are presented different pieces, characterized in that each box is associated with signaling means to indicate to an operator that at least one piece must be taken from this box, in that the system comprises means for selecting boxes according to the pieces to be assemble and a central processing unit to manage the activation of the signaling means relating to the selected boxes, and in that the display unit is made up of modular sub-sets of boxes which each include a local processing module capable of communicating with the unit central processing unit to control the activation of the signaling means relating to the boxes belonging to this modular sub-assembly. This system is designed for implementing the method according to the first object.

 In a preferred embodiment of such a system, the modular subsets correspond to vertical columns of the matrix of boxes. The mounting of the facade and the connection of the local processing modules are thus particularly simple, which is advantageous in particular in cases where the number of available boxes and / or their ergonomics must be changed frequently.

Other particularities and advantages of the present invention will become apparent in the detailed description below of an exemplary embodiment, read in conjunction with the appended drawings, in which:
- Figure 1 is a perspective view of a system according to the invention;
- Figure 2 is a diagram illustrating the architecture of electrical connections in a system such as that of Figure 1;
- Figure 3 is a perspective view taken along the arrow F visible in Figure 1; and
FIG. 4 is a simplified diagram of the electrical connections at the level of a local processing module of the system shown in FIGS. 1 to 3.

 Figure 1 shows in perspective a system for assisting the distribution of parts for assembling objects on an assembly line according to the invention. The description of this system will also reveal the particularities of the method according to the invention.

 In the example shown, the assembly line 1 (drawn diagrammatically on a reduced scale) is used for assembling motor vehicles 2. The system installed at an assembly station comprises a display unit 3 organized in a matrix of boxes 4 in which are presented the different parts to be assembled (not shown).

 The display 3 consists of a juxtaposition of modular sub-assemblies 5 corresponding to vertical columns of the matrix of boxes 4. Each modular sub-assembly 5 comprises a frame made of vertical 6 and horizontal profiles 7. The horizontal profiles 7 carry roller plates not shown for advancing containers of parts in the boxes 4, the parts being supplied by the rear side 8 of the display and advancing to the front 9 accessible to the operator.

On this front 9, the boxes 4 have shelves 10 inclined to present the parts to the operator.

 The front part of each modular sub-assembly 5 is delimited vertically by two front uprights 11, 12 located at the front of the shelves 10. Between the front uprights 11, 12 extend horizontal crosspieces 13. On the front 9 of the display 3, the boxes 4 are delimited by the front uprights 11, 12 and the horizontal crosspieces 13.

 The horizontal crosspieces 13 which delimit the upper part of each box 4 carry signaling means associated with this box. In the example shown, these signaling means comprise, for each box 4, three pairs of indicator lights 15 such as light-emitting diodes. The lighting of one or more of these indicators 15 indicates to the operator that a part must be taken from the corresponding box 4.

The two juxtaposed indicators 15 of the same pair are in principle lit simultaneously. Duplicating the LEDs 15 in this way makes it possible to obtain a higher total light intensity and above all to prevent the failure of an LED from causing systematic omission in the removal of the parts.

 On the modular subassemblies 5 are further mounted sensors 16, 17 intended to detect the removal of parts from the boxes 4 of the matrix.

Each sensor 16, 17 comprises a transmitter 18 and a receiver 19 of juxtaposed electromagnetic ray (see FIG. 4), which have not been shown separately in FIG. 1 for reasons of clarity. These sensors 16, 17 are arranged on the edges of the matrix of boxes 4, behind front uprights 11 and horizontal crosspieces 13 of the front panel 9. They include row sensors 16 fixed on the front upright 11 located at the end left of the front 9 and sensitive to the removal of a part in any of the boxes 4 of a respective row of the matrix, and of the column sensors 17 fixed on a horizontal crosspiece 13 located at the upper end of the front 9 and sensitive to the removal of a part in any of the boxes 4 of a respective column of the matrix.

 On the front upright 12 located at the right end of the facade 9, a reflector, not shown, is arranged opposite each row sensor 16.

Thus, the transmitter 18 of the row sensor 16 emits a ray which crosses horizontally in a central position the areas of access to the different boxes of the row, is reflected on the opposite reflector, then returns in the opposite direction to the receiver 19 of the sensor. in row 16.

When an obstacle such as the operator's hand crosses the access zone to one of the boxes 4 in the row, there is therefore a drop in the output signal from the receiver 19, which is interpreted as detection of a part sample in a box 4 of the row. Likewise, on the horizontal crossbar 13 situated at the lower end of the facade 9, a reflector 20 is placed opposite each column sensor 17. The detection of samples in the columns results from the same principle below. above that in the lines. The radii of the various sensors 16, 17 are shown in dashed lines in FIG. 1. When a part sample is detected simultaneously by a row sensor 16 and by a column sensor 17, this is because this sample has been taken in box 4 located at the intersection of the row and the corresponding column.

 It can also be seen in FIG. 1 that for each modular sub-assembly 5 of the display 3, corresponding to a column of the matrix, three spaced apart column sensors 17 are provided, whose rays pass respectively behind the three pairs of indicator lights 15 associated with each box 4 of the column. This arrangement, preferred when the boxes 4 are relatively large, makes it possible to detect the picking of a part at different locations in the access zones to the boxes of the column. This minimizes the possibility of removing a part without corresponding detection (passage of the operator's hand outside the field swept by the rays of the sensors). This arrangement also makes it possible, together with the three pairs of LEDs, to subdivide one or more boxes in two or three sub-cases can contain differentiated parts, and thus increase the number of parts distributed by the system, the indicators 15 of these sub-boxes can be activated independently of each other.

 The system according to the invention further comprises a central processing unit which, in the example shown in FIG. 1, consists of a microcomputer 25 equipped with a card which manages various functions of the system.

 A code reader 26 is connected to a serial port of the central processing unit. The code reader 26, for example an optical reader of a bar code 27 carried by the vehicle 2 during assembly (FIG. 2), is arranged at the edge of the assembly line 1 to read this code and transmit the information corresponding to the central processing unit 25. Correspondence tables are prerecorded in the central processing unit 25 to associate with this code a group of selected boxes 4 in which are presented the parts to be mounted on the vehicle 2 in assembly course.

 The central processing unit 25 then manages the activation of the indicator lights 15 relating to these selected boxes. Each modular sub-assembly 5 of the display unit 3 comprises a local processing module 30 arranged to communicate with the central processing unit 25. With reference to FIG. 2, it can be seen that the local processing modules 30 of the various modular sub-assemblies 5 are linked together, two by two, one of these modules 30 being connected directly to the central processing unit 25. These connections include a supply line provided in the central processing unit 25 and delivering for example a voltage 12 V DC with a maximum current of 4 A for the supply of the various indicator lights 15 and sensors 16, 17 of the display. The connections between the unit 25 and the modules 30 also include communication lines 33 for the exchange bidirectional of digital information between the unit 25 and the modules 30. This exchanged information includes set-point signals for the indicator lights 15 to be sent by the central processing unit 25 go to the local processing modules 30 and the detection signals from the sensors 16, 17 that the local processing modules 30 send back to the central processing unit 25 so that it can verify that the parts are removed in appropriate boxes.

 The signals coming from the central processing unit 30 are transmitted in multiplex mode, and the local processing modules 30 each comprise a logic circuit such as a microcontroller 34 for identifying the signals coming from the central processing unit 25 and which are intended. The communication protocols between the unit 25 and the modules 30 are chosen according to the architecture of the modular network that they constitute.

 All the indicators 15 and the sensors 16, 17 mounted on a given modular sub-assembly 5 are electrically connected to its local processing module 30. The corresponding cables pass through the uprights 11, 12 and the horizontal crosspieces 13 of the sub-assembly 5 .

 In FIG. 3, it can be seen that the local processing module 30 is arranged on the side of the modular subassembly 5, behind one of its front uprights 11. In the example shown, the module 30 is fixed on a plate 35 ( also visible in Figure 1) located at the top of the modular sub-assembly 5, behind its left front upright 11. The various cables 36, 37 housed inside the front upright 11 and coming from the indicators 15 and sensors 16, 17 of the modular sub-assembly 5 are connected to connectors 38, 39 of the local processing module 30. These connectors (see also FIG. 4) include output ports 38 for the connection of the indicators 15 and the input / output 39 for connecting the sensors 16, 17. In the example illustrated in FIG. 4, each sensor 16, 17 is connected to the module 30 by a cable 37 with three conductors (a positive terminal for supplying the transmitter 18 , a positive terminal to receive the output signal from the receiver 19, and a common negative terminal) and the indicators 15 carried by the same horizontal crosspiece 13 of the front panel 9 are supplied by a cable 36 with nine conductors (for example of the DB9 type: a common negative terminal for all the light-emitting diodes 15 of the cross-member 13 and a positive terminal for each diode 15, with the possibility of connecting eight diodes per cross-member).

 The activation of the indicators 15 relating to the selected boxes 4 of the sub-assembly 5 is controlled by the microcontroller 34 as a function of the reference signals received from the central unit 25 and by means of the power delivered by the supply line 32. The switching of the power for the selective lighting of the LEDs 15 is therefore ensured by program instructions present in the microcontroller 34 and not only by individual pre-established wiring of the LEDs.

As each indicator 15 is individually connected to the module 30, each modular sub-assembly 5 can be used in different ways at different mounting stations without modifying its wiring, but simply by modifying the setpoint signals sent to the local processing module 30. This modification can be carried out easily and quickly by redefining the code / box correspondence tables stored in the central processing unit 25
The detection signals from the sensors 16, 17 are collected at the level of the local processing modules 30 and then sent to the central processing unit 25, which, by comparison with the selected boxes, can determine whether the parts have been correctly removed. If it is thus determined that a part has been taken from an unselected box, or if the operator has omitted to take a part from a selected box, an alert signal can then be triggered, for example an audible signal by a loudspeaker 40 connected to the central unit 25. The operator notified of the error then has the possibility of remedying it.

 Instead of triggering the audible signal, it is also possible to control a switch 41 to interrupt the assembly line 1. This variant has the advantage of dissuading the operator particularly from making mistakes for fear of being assigned responsibility for the interruption.

 The invention provides aid for the distribution and choice of parts which is particularly simple to implement. Indeed, the user can constitute the display 3 as he pleases, depending on the nature and the number of parts to be assembled or the configuration of the work station, by simply grouping the pre-wired modular sub-assemblies 5 and connecting together the local processing modules 30. The size of the display 3 (number of boxes) can freely be increased or decreased as required. It is remarkable that the above advantages are obtained with a system which remains relatively economical, taking into account the standardization of structures, local processing modules, and cabling. In addition, the investment made in this system can pay off satisfactorily because the modular subassemblies 5 are not dedicated to a specific position, but can be reused at other positions to meet the needs of the manufacturer.

 Although the invention has been described with reference to a particular example, it will be understood that this example is not limiting and that various variants can be made without departing from the scope of the invention.

Claims (17)

 1. Method for assisting with the distribution and choice of parts for assembling objects (2) on an industrial assembly line (1), the parts being presented in boxes (4) grouped in a matrix in a display rack (3), characterized in that each box (4) is associated with signaling means (15) to indicate to an operator that at least one piece must be taken from this box (4) and boxes ( 4) according to the parts to be assembled, in that a central processing unit (25) manages the activation of the signaling means (15) relating to the selected boxes (4), and in that the display unit ( 3) by grouping modular subsets of boxes (5) each comprising a local processing module (30) which communicates with the central processing unit (25) to control the activation of the signaling means (15) relating to the selected boxes (4) belonging to this modular subset (5).  2. Method according to claim 1, characterized in that the picking up of parts in the boxes (4) of the matrix is detected by means of sensors (16, 17) mounted on the modular sub-assemblies (5), and in that the information from these sensors (16, 17) is collected at the level of the local processing modules (30) in order to send them to the central processing unit (25) which monitors the detection of the picking up of the parts in the selected boxes (4).  3. Method according to claim 2, characterized in that, when a part sample is detected in an unselected box (4), an alert signal is triggered.  4. Method according to one of claims 2 or 3, characterized in that, when a part sample is detected in an unselected box (4), the assembly line (1) is interrupted.  5. Method according to one of claims 1, 4, characterized in that, to select the boxes (4), we read a code (27) carried by the object (2), this code can take very supports miscellaneous, during assembly, the information read being transmitted to the central processing unit (25) which associates with it a group of selected boxes (4), in accordance with a prerecorded correspondence.  6. Aid system for the distribution and choice of parts, for assembling objects (2) on an industrial assembly line (1), comprising a display (3) organized in a matrix of boxes (4) in which different pieces are presented, characterized in that each box (4) is associated with signaling means (15) to indicate to an operator that at least one piece must be taken from this box (4), in that the system comprises means (26) for selecting boxes (4) as a function of the parts to be assembled and a central processing unit (25) for managing the activation of the signaling means (15) relating to the selected boxes (4), and in that the display unit (3) is made up of modular sub-assemblies of boxes (5) which each include a local processing module (30) capable of communicating with the central processing unit (25) to control the activation of the signaling means (15) relating to the boxes (4) app adjoining this modular sub-assembly (5).  7. System according to claim 6, characterized in that the modular sub-assemblies (5) correspond to vertical columns of the matrix of boxes (4).  8. System according to one of claims 6 or 7, characterized in that sensors (16, 17) are mounted on the modular subassemblies (5) to detect the removal of parts in the boxes (4) of the matrix, in that each sensor (16, 17) is connected to the local processing module (30) of the modular subassembly (5) on which it is mounted, and in that the local processing modules (30) are arranged to send the information from these sensors (16, 17) to the central processing unit (25).  9. System according to claim 8, characterized in that each sensor (16, 17) comprises a transmitter (18) and a receiver (19) of electromagnetic ray electrically connected to a local processing module (30) which supplies the transmitter (18) and receives the output signal from the receiver (19), the beam from the transmitter (18) traversing to the receiver (19) a path which crosses at least one access area to a box (4 ).  10. System according to one of claims 8 or 9, characterized in that the sensors (16, 17) are arranged on the edges of the matrix and include row sensors (16) sensitive to the removal of a part from any of the boxes (4) of a respective row of the matrix, and column sensors (17) sensitive to the removal of a part in any of the boxes (4) of a respective column of the matrix.  11. System according to claim 10, characterized in that several column sensors (17) are associated with the same column of the matrix and spaced apart to detect the removal of a part at different locations in the access zones to the boxes ( 4) of the column.  12. System according to one of claims 8 to 11, characterized in that the electrical connections (37) between the local processing module (30) and the sensors (16, 17) of a modular sub-assembly (5 ) are integrated in the uprights (11, 12) and the crosspieces (13) delimiting the boxes (4) of this modular sub-assembly (5).  13. System according to one of claims 6 to 12, characterized in that the signaling means associated with a box (4) comprise at least two indicator lights (15) mounted on a crosspiece (13) located at the edge of the box (4) and electrically connected to the local processing module (30) relating to the modular subassembly (5) to which the box (4) belongs.  14. System according to one of claims 6 to 13, characterized in that the electrical connections (36) between the local processing module (30) and the signaling means (15) of a modular sub-assembly (5 ) are integrated in the uprights (11, 12) and the crosspieces (13) delimiting the boxes (4) of this modular subassembly (5).  15. System according to one of claims 6 to 14, characterized in that the local processing modules (30) of the various modular sub-assemblies (5) are interconnected, two by two, one of the modules local processing (30) being connected directly to the central processing unit (25), and in that the local processing modules (30, each comprise means (34) such as a microcontroller for identifying the signals originating of the central processing unit (25) and which are intended for them.  16. System according to one of claims 6 to 15, characterized in that, for the electrical supply of the components carried by the modular sub-assemblies (5), the local processing modules (30) are connected together, two by two, one of the local processing modules (30) being connected to a supply supplying a DC voltage.  17. System according to claim 7, characterized in that the front part of each modular subassembly (5) is delimited vertically by two front uprights (11, 12), and in that the local processing module (30) is arranged on the side of the modular subassembly (5), behind one of these front uprights (11).