FR2606178A1 - SYSTEM FOR GUIDING A AUTOMOTIVE TRUCK ON A BEARING SURFACE - Google Patents

Abstract

SYSTEM FOR GUIDING A SELF-PROPELLED TROLLEY 1 ALONG A NON-MATERIALIZED JOURNEY ACCORDING TO A PRE-ESTABLISHED TIME COURSE. ACCORDING TO THE INVENTION, THIS SYSTEM INCLUDES: - AT LEAST ONE DISPLACEMENT DETECTOR 18, 19 ASSOCIATED WITH THE SAID CARRIAGE 1 AND INCLUDING, on the one hand, A FREELY FOLLOWING UNDERGROUND 26 BASED ON A TRAVELING SURFACE AND LIKELY TO RIDE WITHOUT SLIDING ON THIS, AND ON THE OTHER HAND, TWO ENCODERS COOPERATING WITH THIS UNDERGROUND FREELY FOLLOWING 26 AND LIKELY TO CONTINUOUS DELIVERY OF INFORMATION REPRESENTATIVE OF THE BASIC MOVEMENTS OF THE SAID FREELY FOLLOWING UNDERGROUND 26 ON THE SURFACE; - CALCULATION MEANS FOR SUMMARY OF SAID BASIC TRAVEL INFORMATION; - MEANS OF MEMORY IN WHICH INFORMATION CORRESPONDING TO DESIRED POSITIONS IS STORED; AND - MEANS FOR COMPARING THE SAID CALCULATED POSITION INFORMATION, TAKEN AT THE SAID PREDETERMINED MOMENTS, AND THE SAID DESIRED POSITION INFORMATION, WITH THE CORRESPONDING MOMENTS.

Description

The present invention relates to a system for guiding

  of a self-propelled cart on a rolling surface.

such as the floor.

  Systems for guiding heat are already known.

  self-propelled rots, in which guiding means

  electric, optical, magnetic or

  dielectric, such as inductive conductor, tape

  optical or beacons, are arranged along the path

  said trolleys on said tread surface

  is lying. Said carriages comprise, on board, means for recognizing these guide means, as well as controlled driving means, so that they are able to follow the path materialized by said means

guidance.

  The main disadvantage of these known systems lies precisely in 'implantation of these fixed guide means, which constitute a rigid infrastructure. Indeed, any modification of the desired path for

  trolleys for civil engineering works. he is

  that these systems can not be implemented

for all applications.

  For example, it is known that in adaptive workshops, still called flexible workshops, it is common to

  transfer products from one item to another

  intermediate of trolleys. By definition, such

  are intended to facilitate changes in their structure (addition or deletion of machines,

  location change), so that it is strong-

  detrimental to having, at each structural modification, alter the infrastructure of the means of

fixed guidance.

  The present invention aims to remedy this problem.

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  convenient by removing said fixed guide means.

  For this purpose, according to the invention, the system for guiding

  of a self-propelled trolley along a non-ma-

  terérialisé it is desired to see it follow, on a rolling surface, according to a predefined time course, this self-propelled carriage comprising: - rolling means which bear on said running surface and among which at least one is voluntarily orientable to ensure the direction of said

  trolley and at least one is driving to ensure

urging said carriage;

  means for controlling the orientation of said or-

  rolling frame deliberately steerable; and motor means for driving said motor running member, is remarkable in that it comprises: at least one motion detector integral with said driving member;

  carriage and comprising, on the one hand, a wheel member

  freely following on the said surface of

  bearing and capable of rolling without slipping on

  the latter and, on the other hand, two coders cooperating with the-

  said rolling member freely follower and

  to continuously deliver representative information.

  of the elementary movements of that body

  correspondingly free follower on that surface

  this rolling; calculation means for summing said information

  elementary movements, in order to establish information

  calculated positional positions on said road surface.

  element, of said freely follower rolling member; memory means in which information corresponding to desired positions for said self-propelled carriage along said unimportant path is stored at predetermined times of a course

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  reference of said path by said carriage; and

  means for comparing said information of

  calculated position taken at the said predetermined times,

  and said desired position information to the

  corresponding means,

  principal, depending on the result of the comparison,

  so-called means for controlling the orientation of the organism

  deliberately steerable rolling and / or said

  motor means for driving said wheel member

  motor, so that the path actually followed by said carriage tends to coincide with said path

not materialized.

  Since said displacement sensor is integral with the

  carriage, the said information representative of the

  elementary placements of the free running gear

  are also representative of the posi-

  the trolley. As a result, their comparison with

  the information stored in said means for measuring

  moire, information that correspond to reference time positions, allows to determine, at a given time, the difference between the actual position and the reference position of the carriage. This difference, or error, is used to correct the actual trajectory of the truck

  to bring it back to the desired desired path

completed.

  Thus, in the guidance according to the invention, no fixed infrastructure of guiding means materializing

  a reference path is not necessary: the truck se-

  the invention moves autonomously and

  to measure at each moment

  realities. From this he deduces, at predefined times

  born, its actual position and makes corrections

  to get closer to its reference path,

re and preset.

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  Of course, for the comparison of information de-

  written above is significant, it is necessary

  that this information be reported to the same point

  said carriage; this point can be for example, the center of the rolling member freely follower, the point of contact of this member on the running surface, the center of the carriage or else any other point of the

  trolley, chosen for example for the simplicity of

by said calculating means.

  Preferably, said calculating means, memory and

  are grouped in a computer.

  When the system according to the invention comprises only one displacement sensor, it can guide said carriage along said materialized path, without however taking into account the orientation of said carriage

  relative to said path. Also, according to another characteristic

  important feature of the present invention, when the orientation of the carriage relative to the path must be fixed, it is advantageous to provide at least two such displacement detectors arranged spaced on

  said carriage. Thus, it is possible to know,

  said predetermined moments, the actual positions of two points of the carriage and compare these actual positions to the corresponding reference positions. In this case, one can enslave not only the position,

  but also the orientation of the carriage along said work

  desired non-materialized reference stream.

  The desired position information stored in said memory means can be entered in the latter, for example, in the form of a table, after study and analysis of the desired reference path: these are then theoretical reference values. They can

  also be stored by learning, in

  traversing once the desired reference path and recording the measurements of said encoders of the

displacement sensors.

  Each of said displacement sensors could

  take a follower wheel, spontaneously steerable,

  in a screed or the like so as to be able to

  turn around a first axis parallel to the said

  running surface, said screed being itself

  with respect to said self-propelled carriage so as to

  freely rotate around a second axis orthogonal to said running surface. In this case, one of the said

  encoders would be associated with said wheel to measure the

  rotation of it around said first axis,

  while the other of the said encoders is associated with

  said clevis to measure the angle of rotation of this

  last around said second axis. Such a detector

  therefore, information concerning the direction (second encoder) and amplitude (first sensor) of

  elementary displacements of said follower wheel.

  However, preferably, each detector comprises, at

  as a free-running rolling member, a spherical

  associated with two pebbles, arranged in two planes dia-

  different metrics of said sphere, orthogonal to

  the rolling surface, so that, on the one hand, the rim of each can roll without sliding on said sphere when it rolls around that of its diameters which is orthogonal to the corresponding roller, and secondly that said sphere can freely slide relative to the rims of said rollers, as it rolls around its diameter orthogonal to said rolling surface, said encoders respectively measuring the

angles of rotation of said rollers.

  In this case, said encoders thus deliver two components

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  of said elementary displacements, respectively

  parallel to the planes of said rollers.

  Advantageously, but not necessarily, the plans

  said two rollers of a detector are perpendicular

  res. Thus, we obtain two perpendicular components

  said elementary displacements.

  If the system according to the invention comprises two detections

  it is advantageous for the four rollers of these to be two by two parallel, so that the components of the elementary displacements measured by the two detectors are two by two parallel and

therefore directly comparable.

  In an advantageous embodiment, such a detector comprises a housing enclosing said sphere, said two rollers and said encoders, the bottom of said case having an opening to allow the sphere to rest on said rolling surface and said sphere being Pi support in said.boltier on said two rollers, as well as on a third roller whose

  rim can be slid and slid with respect to said spherical

  re. Preferably, the three rollers rest on the upper part of the sphere and elastic means are provided between said carriage and the casing of said detector for pressing the sphere on said rolling surface.

  through said housing and said rollers.

  Sliding pads may be arranged under the bottom of said housing to alleviate the reaction efforts

  exerted by said rolling surface on said spherical

re.

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?

  Advantageously, the system carriage complies with the

  vention comprises at least a motodirector group in which the deliberately steerable rolling member is also motor. Two such motodirection groups are preferably provided, spaced along the longitudinal axis of said carriage. Orientation commands of the latter to correct position errors are then more quickly and better executed than with a single

motodirector group.

  The figures in the annexed drawing will make it

  the invention can be realized. In these figures,

  identical references refer to semantic elements

  lar. FIG. 1 is a diagrammatic view, in elevation, with partial cut-away, of an exemplary embodiment of FIG.

  trolley automot-u: intended for the system conform G the pre-

this invention.

  FIG. 2 and a bottom view of the trolley of FIG.

gure 1.

  FIG. 3 is an enlarged view, in section, according to the

  line III-III of Figure 1, a movement detector

according to the invention.

  Figures 4 and 5 are sections, respectively

  lines IV-IV and V-V of Figure 3.

  FIG. 6 is a bottom view of the sensor of FIG.

gures 3 to 5.

  Figure 7 is a sectional view along the line

VII-VII of Figure 6.

  Figure 8 shows the synoptic diagram of the system of

  guiding the carriage of Figures 1 and 2.

  Figure 9 is a diagram illustrating schematically

  the operation of the guidance system in accordance

vention.

  Figure 10 is a flowchart of the separate operation of

  quence of the guidance system of Figure 8.

  The self-propelled carriage 1, shown in FIGS. 1 and 2,

  comprises a frame 2 of longitudinal axes L-I and trans-

  versal t-t (determining the center C of said chassis) ei

  is provided with bumpers 2a at its longitudinal ends

  tions. It is represented purely schematically and only the elements directly related to the present

invention are indicated.

  The self-propelled carriage 1 is intended to circulate on a

  running surface S, following a path or trajectory

  predetermined and non-materialized T (see fig.

re 9).

  The self-propelled carriage 1 rests on the rolling surface

  S via several wheels 3 (four in FIGS. 1 and 2) and at least one wheel 4 (two

in Figures 1 and 2).

  Each wheel 3 rotates freely about an axis 5 of a mount 6, which itself freely rotates about an axis 7, linked to the frame 2. The axes 5 are parallel to the

  rolling surface S, while the axes 7 are

  pendicular to this one. Thus, the wheels 3 constitute.

  follower support wheels, spontaneously orientable.

  For example, they are arranged symmetrically in pairs.

9-2606178

  relative to the center C of the carriage 1.

  Each wheel 4 can be rotated about an axis 8 by a motor 9. The assembly of a wheel 4 and

  associated engine 9 is carried by a mount 10 solid-

  Rotating a ring gear 11, with which a pinion 12 meshes. The pinion 12 can be driven.

  in rotation by a motor 13, to rotate the

  4-8-9-10-11 appears around an axis 14 linked to the frame 2, with respect to which it can rotate thanks to a bearing system 15. The axes 8 are parallel to the surface of

  bearing S, while the axes 14 are perpendicular

  to this one. Thus, each set including a

  wheel 4, an axis 8, a motor 9, a frame 10, a cover

  11, a pinion 12, a motor 13, an axis 14 and a

  bearing system 15 constitutes a motodirector group.

  In the example of FIGS. 1 and 2, two such

  groups, respectively bearing the reference numbers

  16 and 17, arranged on the longitudinal axis L-L of the carriage, symmetrically with respect to the center C.

  The self-propelled carriage 1 also comprises two detections

  identical displacement units 18, 19, whose structure

  ture will be indicated below, with reference to FIGS. 3 to 7.

  These detectors are for example arranged symmetrically

  relative to the center C of the chassis 2.

  In addition, in the frame 2 of the carriage 1 is provided a bolt-

  tier 20, in which are locked a computer 21 and a memory 22, for controlling, as described below, the motors 9 and 13 of the motodirecteur groups

  16 and 17 depending on the measurements made by the detectors

  movers 18 and 19 (see also Figure 8). As shown in FIGS. 3 to 7, each displacement detector 18 or 19 comprises a boltier 23,

  two parts 23.1 and 23.2 assembled according to a plan of -

  24. Each housing 23 is pressed elastically towards the running surface S by springs 25 bearing between the lower part of the frame 2 and

  the upper part 23.1 of the housing 23.

  Inside each boltier 23 is enclosed a sphere

  26, passing through the bottom 27 of the casing 23 through an opening

  28 and resting on the rolling surface S. The

  sphere is, inside the housing 23, held in place

  this by three rollers 29,30 and 31, directed according to plans

  diameters different from said sphere, orthogonal to the

  said rolling surface S. The rollers 29,30 and 31 are disposed above the diametral plane of the sphere 26 parallel to the rolling surface S and are supported by their rim on said sphere. Thanks to the holding action exerted by the rollers 29, 30 and 31 on the sphere 26 and the action of the springs 25 on the boltier 23, said sphere

  26 is supported on the running surface S by its

  lower tie through the opening 28; in conditions

  such that it can roll without slipping on the said

running surface.

  Optionally, to limit the efforts of reactions

  bent by the rolling surface S, on the spheres 26, sliding pads 32 can be provided under the bottom 27 of the boltier 23. Of course, the height of these sliding pads 32 must correspond to the height of the projection of the sphere 26, outside the opening 28 of the housing 23. The roller 29 is freely rotatably mounted about an axis 23, parallel to the running surface S of a floating mount 34 and is pressed elastically towards the

  the sphere 26 by a spring 35 disposed between said mor-

  float 34 and a fastening lug 36 secured to the

boltier 23.

  Likewise, the rollers 30 and 31 are freely rotatably mounted

  around the respective axes 37 and 38 parallel to the over-

  bearing face S and provided in fasteners 39,40 connecting said rollers 30 and 31 to the housing 23. In addition, on the pins 36 and 37 are keyed respective encoders 41

and 42.

  So when the carriage 1 moves on the surface of

  bearing S, the spheres 26 of the detectors 18 and 19 routers

  slowing freely, without slipping, on said rolling surface S by rotating around their centers. When the relative movement of such a sphere 26 relative to said rollers 29,30,31 associated is transverse to the planes of said rollers, the sphere slides on the rim thereof

  without causing their rotation. On the other hand, when the

  relative threading of a sphere 26 with respect to one of the

  said rollers 29,30,31 associated is directed according to the plane of the roller concerned, this roller rotates about its axis (33,37, 38) rolling without sliding on said sphere. The rotation of said rollers, and in particular that of the rollers 30 and 31,

  is therefore representative of the displacement of the sphere 26 as-

  company, parallel to the plans of said rollers. As a result, the encoders 41 and 42 associated with the rollers 30 and 31 (of which

  the plans are for example orthogonal) deliver

  formations representative of the movements of the sphere 26 corresponding parallel to the planes of said rollers and 31. Since these are arranged in different diametrical planes, the respective information of the

  encoders 41 and 42 constitute two components of the

  elements of the sphere 26 associated with the rolling surface S. Preferably, the rollers 30 and

  31 of the two detectors 18 and 19 are two by two parallel

the.

1 2 2 606178

  Thus, by measuring by coders 41 and 42 the

  elementary displacements provided by the sphere 26 of each detector 18 and 19, we know for each

  elementary time interval, the elementary displacement

  corresponding re of each of the two detectors. By adding these elementary movements measured in continuous, we can know, at every moment, the path followed

  by each detector 18 and 19 from an initial position

  the instantaneous position of each detection

the position and the instant orientation

born from the trolley 1.

  FIGS. 8 and 9 illustrate the operation of the guidance system according to the invention, on the basis of this

which has been described above.

  The self-propelled truck 1 must follow the reference path

  desired (T) on the bearing surface (S) so as to

  to find aax points PO, P1, P2, ... Pi, ... Pn of this path, respectively at successive instants

  to, tl, t2, .. t, ... t .. In the example shown on the fi

  I, it has been assumed that the path (T) corresponds to the

  naked reference jet must follow center C of carriage 1.

  In the memory 22 are stored pairs of values.

  their Pi, ti, thus defining the reference path (T).

  At the initial moment t0, the carriage 1 is set up so that its center C coincides with the initial point Po and that its front is directed towards the point P1 to which it will have to be at the following instant t1, after what is he

started.

  The computer 21 continuously receives the information from the sensors 18 and 19 and adds them up, so that it knows at

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  every moment the actual position of the carriage 1, by

port to the initial position Po.

  At any instant ti (with _-ciîn), the carriage 1 should occupy the position li, for which its center C coincides with the corresponding point Pi of the path T.

  If this is not the case and if the carriage 1 occupies a po-

  erroneous position li ', its center C following an erroneous trajectory T', the computer of the carriage 1 knows, thanks to the contents of the memory 22 and the measurements of the detectors 18 and 19, the positional errors dl and d2 of said detectors 18 and 19 , and therefore the position error e of center C. It

  can therefore act on the motors 9 and 13 of the moto-

  rectors 16 and 17 for this erroneous trajectory T '

  converges towards the reference trajectory T, in order to cor-

  handle the detected position error.

  Thus, thanks to the system according to the invention, the self-propelled carriage 1 is used to follow the reference path T.

  In FIG. 10, the flow diagram of the function

  In this figure, the frames represented have the following meanings:: entry of the starting point PO 51: entry of the arrival point Pn 52: reading of the reference path T 53: search of the theoretical position Pi at the instant ti 54: calculation of the differences d1, d2, e: choice of the convergence point of the erroneous path T 'on the reference path T 56: generation of the guidance instructions to the motors 9 and 13 of the groups 16 and 17 57: end of trip? 57A: yes 57B: no 58: waiting for instructions 59: taking into account the encoder measurements 41 and 42 of the detectors 18 and 19 60: test of validation of the measurements 61: calculation of the elementary displacements of the center of the trolley 1 between the instants ti-1 and ti

  62: calculation of the position of the carriage 1 at time ti.

Claims (12)

  1.- System for guiding a self-propelled carriage (1) along a non-materialized path (T) that one wishes to see it   follow, on a running surface (S), according to a   This self-propelled carriage (1) comprises: - rolling elements (3, 4) which bear on said running surface (S) and of which at least one (4) is deliberately adjustable to ensure the   direction of said carriage (1) and at least one (4) is   tor for propelling said carriage (1); means (11, 12, 13) for controlling the orientation of said deliberately steerable rolling member (4); and - drive means (9) for driving said motor running gear (4), characterized in that it comprises: - at least one displacement sensor (18, 19) integral with said carriage (1) and comprising, on the one hand, an organ of   freely follower bearing (26) resting on said   rolling face and capable of rolling without sliding on it, and secondly, two encoders (41 and 42) cooperating with said rolling member freely follower   (26) and capable of continuously delivering information   representative of the elementary displacements of the   rolling member freely follower (26) on said sup- rolling face (S);   calculating means (21) for summing up said information   elementary movements, in order to establish   calculated position formations, on said running surface (S), of said freely follower rolling member (26);   memory means (22) in which are stored   information corresponding to positions   said self-propelled trolley (1) along said tread   non-materialized jet (T) at predetermined times of a   reference course of said path by said self   motor (1); and - means (21) for comparing said computed position information taken at said predetermined times and said desired position information at times   corresponding means (21) for comparing   depending on the result of the comparison, said means (11, 12, 13) for controlling the orientation of the deliberately steerable rolling member (4) and / or said driving means (9) for driving of said motor running member (4), so that the path actually followed by the carriage tends to coincide with said path not materialized.   2. System according to claim 1, characterized in that said calculating means, said memory means and said comparison means are   grouped in a computer (21,22).   3.- System according to one of claims 1 or 2,   characterized in that it comprises at least two displacement detectors (18, 19) arranged spaced apart on said self propelled trolley (1).   4.- System according to any one of claims 1 to   3, characterized in that each displacement detector   (18, 19) has a follower wheel, spontaneously orientated   mounted in a clevis or the like so as to be able to   freely turn around a first axis parallel to the-   said running surface (S), said clevis being itself   same mounted relative to said self-propelled carriage (1) so as to be freely rotatable about a second axis orthogonal to said running surface (S), one of said encoders being associated with said wheel for measuring the rotation angle of it around said first axis, while the other of said encoders is associated with said yoke to measure the angle of rotation of the latter around said second axis.   5. System according to any one of claims 1 to   3, characterized in that each displacement detector (18, 19) comprises, as a freely-follower rolling member, a sphere (26) associated with two rollers (30, 31) arranged in two different diametrical planes of said sphere orthogonal to said running surface (S), so as, on the one hand, that the rim of each of said rollers can roll without sliding on said sphere (26) when it rolls around that of its diameters which is orthogonal to the corresponding roller and, on the other hand, that said sphere (26) can freely slide relative to   the rims of said rollers (30,31) when it rolls   its diameter orthogonal to said roughness surface   (S), said encoders (41,42) respectively measuring   the angles of rotation of said rollers (30, 31).   6. System according to claim 5, characterized in that the planes of said two rollers   (30,31) of a detector (1819) are perpendicular.   7. System according to claims 3 and 5,   characterized in that the four rollers (30,31) of the two   detectors (18,19) are two to two parallel.   8. System according to any one of claims 5 to   7, characterized in that the displacement sensor (18, 19) comprises a boltier (23) enclosing said sphere (26), said two rollers (30, 31) and said encoders (41, 42), the bottom (27). said casing (23) having an opening (28) to allow the sphere (26) to rest on said running surface (S) and said sphere (26) bearing in said casing on said two rollers (36, 31), as well as on a third roller (29) whose rim can roll and slide with respect to said sphere (26). 9.- System according to claim 8, characterized in that the three rollers (29,30,31) rest on the upper part of the sphere (26), and in that elastic means (25) are provided between said carriages (1) and said casing (23) of said detector (18,19) for pressing the sphere (26) on said surface of bearing (S).   10. System according to claim 8, characterized in that sliding shoes (32) are   disposed under the bottom (27) of said boltier (23).   11. System according to any one of claims 1 to   , characterized by only the self-propelled carriage (1) comprises   at least one motodirector group (16,17) in the water   gane of roulem.ent voluntarily orientable (4) is also motor.   12. System according to claim 11, characterized in that the self-propelled carriage (1) comprises two motodirection groups (16, 17), spaced along   the longitudinal axis (L-L) of said carriage (1).