FR2524349A1 - METHOD AND DEVICE FOR IDENTIFYING AND / OR LOCATING PARTS CARRIED BY A CONVEYOR - Google Patents

Abstract

PROCESS FOR IDENTIFICATION AND / OR LOCATION OF PARTS TRANSPORTED BY A CONVEYOR OR THE LIKE USING EQUIPMENT INCLUDING AT LEAST ONE OPTICAL SYSTEM 7 DELIVERING A SENSITIVELY FLAT LUMINOUS BEAM 9 ASSOCIATED WITH A LIGHT SENSOR AND CONNECTED TO MEANS OF ANALYSIS AND PROCESSING, PROCESS CHARACTERIZED IN THAT IT CONSISTS OF ARRANGING THE OPTICAL SYSTEM TRANSVERSALLY TO THE CONVEYOR 1 SO AS TO LIGHT THE ROOM 11 ON THE SIDE, TO CARRY OUT REPRESENTATIVE MEASUREMENTS OF THE PROFILE OF THE PIECE DURING THE PATH THROUGH BEAM, TO COMPARE THE PROFILE THUS DEFINED WITH PROFILES PREVIOUSLY STORED SO AS TO DETERMINE THE PARAMETERS OF IDENTIFICATION, ORIENTATION AND OR LOCATION OF THE PART.

Description

1 - Method and device for identifying and / or locating

  parts transported by a conveyor.

  The present invention relates to a method as well as to an identification device, and if necessary to localization of

  parts transported by a conveyor in particular.

  The problem of recognition and definition of the

  sition and orientation of parts arranged in a random manner on a conveyor, and in particular on a roulant carpet already discussed,

  and has been the subject of several attempts at solutions.

  However, the solutions proposed to date are mainly

  an image sensor such as a T V camera placed vertically above the rooms and thus the stage and thus require lighting.

additional more or less complex.

  Indeed the disadvantage of most of these visual devices

  lies in the fact that they require a good contrast between the

  what to observe and the support on which it rests; but such a contras-

  you are often absent in the workshops where the pieces dirty the

  so that the assembly generally has the same hue.

  The present invention aims to overcome the aforementioned drawbacks by providing a method and a device for its implementation completely insensitive to both ambient lighting conditions and the absence of contrast between the part and its support

  while being of simple installation designating it more particularly

  for industrial use.

  According to the present invention, the method for identifying and / or locating parts transported by a conveyor or the like using equipment comprising at least one optical system delivering a substantially planar light beam associated with a sensor

  of light and connected to means of analysis and treatment, is

  in that it consists in arranging the transverse optical system

  to the conveyor so as to illuminate the piece from the side, to make representative measurements of the profile of the part while it 2 - scrolls through the beam, to compare the profile thus defined with profiles previously stored in memory so as to determine the identification, orientation and / or location parameters of the part. According to another characteristic of the invention, the method consists in using two optical systems that do with the direction

  in advance of the conveyor angles 1 and 2 respectively, and asso-

  each to a reflector located on the opposite side of the conveyor,

  to locate the transported parts.

  According to the present invention, the device for identifying and / or locating parts transported by a conveyor, and of the type comprising equipment comprising at least one optical system delivering a substantially plane light beam associated with a sensor

  of light connected to means of analysis and treatment is

  characterized in that the optical system is arranged transversely to the conveyor so as to illuminate the room whose scrolling through the beam triggers the sensor which provides measurements representative of the profile of the latter, which profile is

  compared to profiles previously stored in memory so as to determine

  undermine the identification, orientation and / or localization

the room.

  According to another characteristic of the invention, the measures

  presentatives of the profile of the part are obtained using the

  information delivered by an encoder which gives the position of the conveyor.

  Other features and advantages of the present invention

  will appear following the following description of the process and

  two modes of execution of the device by applying,

  only by way of example and represented in the accompanying drawings, in which FIG. 1 represents a schematic diagram implementing a

light curtain -

  FIG. 2 represents, seen from above, a two-tier installation

bright waters.

  FIG. 3 represents a variant of the installation of FIG. 2. FIG. 4 represents the flowchart of the data acquisition cycle.

  Figure 5 shows the flowchart of the learning cycle.

  FIG. 6 represents the flowchart of the execution execution of the recognition.

  Figures 1 and 2 represent the schematic diagram of the dis-

  positive embodiment implementing the method according to the invention and which

  takes a conveyor having a treadmill 1 moved by means

  not shown in an OX direction and whose posi-

  in this direction is given by an encoder 3 mounted, for example,

  on the drive roller 5; transversely to the carpet is disposed a known type of optical system 7 which delivers a substantially plane beam or light curtain 9 which illuminates the side of the parts it disposed on the carpet 1 and whose passage through the beam occult a portion of the light curtain representing their height, the unobstructed portion of the curtain being received by an associated sensor

  system after reflection on a reflex reflector 13 for example

placed on the other side of the carpet l.

  Of course, and according to one variant, the reflector 13 can

  be replaced by the sensor which no longer forms an integral part

of the optical system.

  As the conveyor advances, and therefore the part 11, the assembly (7, 13) performs a number of measurements

  h (t), about 100 per second, representing the variations in the

  h the section of the room as a function of time.

  When it comes to identification and location of parts, the device according to the invention shown from above in FIG. 2, comprises two optical systems (7 ', 7) whose beams which intersect in the form of with the OX direction of the conveyor the angles and O respectively, said systems being associated i 2

  with reflectors (13, 13 ') located on the opposite side of the conveyor.

  According to a variant of the device shown; view from above, in Figure 3, it is possible to examine the same room by the same light curtain successively from two different angles e 1 and 2 and this thanks to a curtain 9 at an angle with the direction OX which is associated to a first mirror 15 located on the other side of the carpet and which returns the beam to a second mirror 17 suitably arranged and on the same side of the carpet as the mirror 15 and which returns the

  beam which makes an angle & with the direction OX towards a reflection

  13 on the same side of the carpet as the system 7 delivering the curtain 9.

  The method according to the invention comprises the following steps: the time information h 1 (t), h 2 (t), x (t) provided by the systems 7, 7 'and the encoder 3 respectively are transmitted to a

  computer system of the standard type or any other equivalent system

  slow whose role is to turn them into information h 1 (x) and

  h 2 (x) representing the profile of the part to be recognized and localized

  be seen from two different directions.

  according to a variant, the values h 1 (x) and h 2 (x) are obtained directly

  by triggering the curtain measurements by means of the encoder, either at regular intervals, every five millimeters for example, or for certain predetermined positions giving information

relevant on the profile.

  the profiles thus recorded are then compared with the profiles

  previously stored in memory The analysis of the profile gives, after

  numerically, the nature of the part, the bearing face and its orientation In the case of parts with single or multiple plane of symmetry, the analysis of two profiles h 1 (x) and h 2 (x) is necessary to lift ambiguities The angles at 1 and & 2 are

  chosen according to the symmetries presented by the

  lyser Once the parameters of orientation and identification of the support surface determined, the knowledge of the two instants of start of occultation allows to simply calculate the position of the piece on the carpet in the y direction orthogonal to the direction

x defined previously.

  As mentioned above, if only the identification of

  the room, we can use a single light curtain.

  The pattern recognition procedure thus described requires

  site a prior learning of acquiring and memorizing -5-

  certain parameters characterizing the profiles of known pieces orien-

  This learning can be done in a similar way.

  moderately using the same device, scrolling the coin on each side and rotating it by a certain angle

between two successive passages.

  In what follows, we will describe the flowcharts relating to the method and device described above being understood that they make

  integral part of the description of the fact that they are reading

obvious to those skilled in the art.

  The implementation of the technique begins with a calibration of the site which involves: the direct measurement of the angles O and O 'i 2 direc

  spotted in the OX scrolling direction space

  voyeur as well as measuring the height of the latter.

  the direct identification in the space of the point of intersection of the two

light beams.

  calibration of the light curtains and the encoder, for example by

  passing on the conveyor a cyclider of known dimensions and

  vertical axis, and recording his profile.

  Figure 4 shows the flow diagram of the acquisition sub-program.

  sition of data relating to a part face and usable

  both during learning and exploitation.

  The cycle starts with the indication of the number of the measurement de-

  signed by the parameter i followed by the reading of the counters h and x and the comparison of the value read h and the height of the conveyor h allowing in the case oh> hc to conclude the presence of a part, and therefore of memorize the values x (i) = x and h (i) = h and redo the measurements passing from i to i + I, in the opposite case and if i OO to conclude the passage of the part, and thus to finish

  measurements and store the data x (i), h (i).

  FIG. 5 represents the flowchart relating to the learning of the part for a given face thereof. The operating cycle starts with an angle i 1, representing the orientation of the part around the vertical, equal to zero followed by the creation of the file x (i), h (i) according to the flowchart of FIG. 4, and this for each

  successive values => X + L A less than 3600, the step of

  L i being chosen depending on the shape of the piece and the desired accuracy. After a complete turn of the piece we extract from the file thus obtained the characteristics of the profile, that is to say the points and the remarkable mathematical magnitudes of the silhouette of the piece for

  each value of o L Of course, we perform during the apprenticeship

  as many cycles as the coin has faces.

  Figure 6 shows the flowchart of the run cycle of

  the recognition that we are beginning, as far as the first

  first curtain, by the creation of the file x (i), h (i) as defined in FIG. 4 and relating to the piece that passes in front of said curtain,

  then extracts from this file the outstanding characteristics of

  lative for example at the height or width of the room compared with those stored in memory during the learning phase, which allows to obtain the relative information

  at the orientation o (of the part, or at its position x.

  As indicated above, the position in the direction of the beginning y of the piece can be determined by the study / occultation of

  two curtains; for this purpose we note the value x (0) relative to the first

  first measurement made by the first curtain, likewise and after having performed the same procedure as that defined above for the second curtain is also determined the value x '(O) relative to the first measurement made by the second curtain, the comparison of x (OY and x '(0) makes it possible to obtain, by a simple calculation, the value y relating to

the position of the room.

Claims (5)

CLAIMS l / A method for identifying and / or locating parts transported by a conveyor or the like using equipment comprising at least one optical system (7) delivering a substantially planar light beam (9) associated with a light sensor and connected to analysis and processing means, characterized in that it consists in arranging the optical system transversely to the conveyor (1) so as to illuminate the part (11) from the side, to perform measurements representative of the profile of the part as it passes through the beam, to compare the profile thus defined with profiles previously stored in order to determine the parameters of identification, orientation and / or location of the room.   2 / A method according to claim 1, characterized in that it consists in using two optical systems making with the advance direction of the conveyor angles O-, and G 2 respectively and associatedchacun   a reflector located on the opposite side of the conveyor, so as to locate read the parts transported.   3 / A method according to claim 1, characterized in that it consists in using a single optical system whose beam is at an angle λ with the direction of advance OX of the conveyor and associated with a system of   mirrors located on the other side of the conveyor and which refers to the   at an angle G to a reflector on the same side of the convoy than the optical system.   4 / Device for identifying and / or locating trans-   carried by a conveyor and of the type comprising equipment comprising   at least one optical system delivering a sensitive light beam   plan associated with a light sensor and connected to means of   lysis and processing, characterized in that the optical system is disposed transversely to the conveyor so as to illuminate the side of the room whose scrolling through the beam triggers the sensor which provides representative measures of the profile of this -8- last, a profile that is compared to profiles previously   memory in order to determine the parameters of identification, from   location and / or location of the room.   Device according to claim 4, characterized in that the   Representative measures of the profile of the part are obtained by using   information provided by an encoder giving the position of the conveyor.   6 / Apparatus according to claim 5, characterized in that it comprises   two optical systems whose beams make with the direction of   conveying the angles O 1 and P 2 respectively and each associated with a reflector located on the opposite side of the conveyor, so   to locate the transported parts.   7 / Apparatus according to claim 5, characterized in that it com-   carries a single optical system whose light beam makes an angle & 1 with the direction of advance of the conveyor and associated with a system   mirrors placed on the opposite side of the conveyor and   at an angle e 2 to a reflector on the same side as the optical system.