FR2812085A1 - Procedure for realizing cartography of effects on ground of passage of vehicle, involves measuring parameters of these effects by at least one matrix of sensors comprising load sensors, identical or not, and preferably three-dimensional - Google Patents

Abstract

The procedure for realizing a cartography of the effects on the ground of the passage of a vehicle involves measuring the parameters of these effects by at least one matrix of sensors comprising load sensors, identical or not, and which are preferably three-dimensional, and if necessary a means of characterizing the form and/or localization in the ground location where the effects or pressures are felt. A cartography is then made up of the effects on the ground or contact on the ground by an appropriate processing means utilizing the relationship between the effect created and vehicle and object or part of it having generated the effect. An Independent claim is included for a device for carrying out the said procedure.

Description

Device and method for effect mapping

on the ground of the passage of a vehicle.

  TECHNICAL FIELD OF THE INVENTION The present invention relates to the study of any "ground" area undergoing effort or contact (generating a force) from an object passing over or over (or in the vicinity, in the case of studies of tunnels etc ...) of said area, in particular of an object or vehicle passing over or in the vicinity of, or rolling on, such area, and more particularly the study of the tire contact areas, wheel treads of any type, and / or - any "ground" area, undergoing effects (with and / or without contact) due to the passage of an "object or vehicle", (land, air or sea, etc., including models), or at least part of that object or vehicle "(hereinafter together and separately" object or vehicle "or simply" object "or" vehicle " as will be understood by those skilled in the art) - whether the object moves (with or without contact) on, above or in the vicinity of the area, or the opposite (ie e displacement of the area relative to the object, or possibly both simultaneously relative to each other), for example in the wind tunnel or hull basin in the second case, and concerns in particular but for non-limiting - the technical sector of motor vehicles and more particularly devices and methods for improving their control, and more particularly - the technical sector of the study of such devices and processes for controlling their tires (or treads, of all types of wheels) and the conditions of contact thereof on the ground, for example on the road, and the present invention particularly relates to the precise measurement of the contact area and the mapping of the forces generated by a tire (or any tread and the like) at this contact area, as well as - the mapping of the effects on the ground generated by the passage of a vehicle or object or a part of it has passed. nt

  above, or in the vicinity of, said area.

  In what follows, we will try, as often as possible, to particularize the terms and terms "contact areas", "area of efforts", "effects on the ground," "vehicle", "object", etc. but, unless expressly indicated, the skilled person will understand that these terms and terms all relate globally and individually to the above, and will put each term in context, and if necessary generalize the meaning according to the paragraph previous and

examples provided.

  For example, the zone of forces may be horizontal, for example an automobile test track, and / or vertical (wall of a tunnel or measurement of side effects caused by the passage of a vehicle, a train, etc ...) and / or inclined at any other angle, and in general of any position and shape, according to the tests to be carried out, including the mixed solutions (a part of the ground area and one or several parts "above ground", etc ...), and / or single and / or fractionated in o10 several identical or different measuring areas, positioned in space according to the needs of the measurements, as will easily understand the man of trade, for example an area integrated into a track

  and a second gantry area above the runway, etc .....

  the whole being referred to simply as "ground". Similarly, "above" will include the word "in the neighborhood", which will be

  also obvious to the skilled person.

  PRIOR ART: Fingerprint measuring systems (that is to say the areas of the ground affected by the contact of a tire) are known to date by means such as illumination by a "flash" light and measurement. in

the domain of the visible.

  Current systems do not provide much discrimination between

  the contact area and the areas of the ground that do not touch the tire.

  When measuring at high speed, the contrast of the impression is small,

  and therefore also the accuracy of the measurement.

  There are technologies advocating the use of sensor matrices, for example of the order of 30 x 30 sensors, which represents of the order of 3000 channels; the system is totally unmanageable and, moreover, is not

  reliable because a number of sensors is, statistically, defective.

  Systems are also known that do not represent a "true" mapping of the contact area but a simple overall measurement. For example, a PirelliTM technology is known according to which the vehicle

  rolls on a piezoelectric rubber membrane.

  Such systems (we also know a TOTALTM technology, one of which uses a matrix of sensors to perform an average of the measurements, and moreover to stop) give only an overall measurement where the forces along the x, y and z, and in particular x and y, can not be discriminated. They are also very inaccurate and can only be used at very low speed. Moreover, they are part of systems requiring a number of crippling channels for the transfer of information (from

3000 orders).

  (As will be seen below, the invention measures on the contrary, and

  precisely, the effort to the place where it was generated).

  There is therefore a significant and recognized need for a device and a method for performing a true and complete mapping of efforts or effects on the ground during the passage of a "vehicle or object", including, but not limited to, a measurement of the contact area between a tire and the roadway, both at low and high speed, and the recording of the forces created in this particular case by the tire at the level of said contact area, or a complete cartography of the effects on the ground (surface of the "ground", seabed, etc.) of the passage of a "vehicle or object", for example a chassis, a

  aircraft wing model, ship hull model, etc ...

  FIELD OF APPLICATION The invention applies to any object or rolling vehicle, and in particular to any motorized or non-motorized vehicle, rolling, or passing over or in the vicinity of the "ground" such as a vehicle chassis, or overhead. as an aircraft, or a seafarer, such as a ship's hull, exerting an effect on the land or seabed, when passing over or over or in the vicinity of a given "area", called "contact area" when 'there will be effective contact, and' effects area 'when there is no contact, if any, and in particular, but not limited to

  those equipped with tires or treads.

  The invention also aims at mapping ground effects of "vehicles or objects", of all types, or part (s) of such "objects or vehicles", with or without tires, or more generally possessing or not possessing point of contact with the ground, at least at the time and place ("area,") of the measurement, eg air-cushion vehicles, ground effect, "aircraft, ships, and the like, and that, even for vehicles fitted with tires or treads, the mapping of the ground effects of the passage of the vehicle not created by the tires or treads, or generally by any wheel, or even by any surface generating a effort, including even a footprint or footprint of a walker or runner, or the shock or passage of a tennis ball, "football" ball, etc., or the passage of a shell or ball, or a fingerprint, and for example created by the passage from below the chassis or any other part of the vehicle, or by the passage of an aircraft wing or a hull or hull of a ship, in particular in the form of models in a wind tunnel

  aerodynamic or respectively hull basin.

  All this applications will be automatically (and for simplicity)

  included in all the descriptions which will follow, without being useful

  to repeat them, the skilled person naturally being able to adapt any example to a different application. For example, "tire contact area" or "wheel" or "object" or "vehicle" and similar terms, will cover all of these applications, as well as all applications that will be accessible directly to the man

  of business, if necessary with a simple adaptation.

  Similarly, the terms "effort measurement" and "ground effect measurement" will be interchangeable, except in specific cases mentioned or that the skilled person will identify without any difficulty in function

context.

  The most general term, covering all of the foregoing, will be "ground effects" and "ground effects mapping", the term "ground" or "ground area" meaning as a person skilled in the art will have understood from the foregoing, any surface (s) of geometry (s) and any positioning (s) undergoing an effect (efforts), with and / or without contact, from an object or vehicle, or portion of an object or vehicle, passing over, above, below or in the vicinity of that area, the vehicle or object being movable relative to the area, or vice versa, or both being movable relative to each other. "Contact" area studies will be a special case when the measurement relates to an area undergoing physical contact with the

  vehicle or object, including a tire.

  Objective The objective of the device and method according to the invention is to achieve a real mapping effects, including efforts, created on the ground by the passage of a "vehicle or object", or one or more parties of this vehicle or object, and in particular to take in a particular non-limiting case (mapping of the contact area forces) an accurate impression of the part of the tire in contact with the ground (contact area) when passing the in the whole useful range of velocities.This is generally to implement a: * Stress measurement method + visualization process + treatment of reconstruction of the mapping of the stresses * Pressure measurement method (or other quantity) + visualization method + process for reconstituting the pressure map (or other quantities) The block diagram of the process is shown in FIG. 1 below.

  applied to the measurement of contact area mapping.

  In a particular non-limiting case, another objective, in relation to the first, is to map the forces experienced by the contact area of a tire. The objective of the force measuring device is to establish a measurement and then a mapping of the three-dimensional forces generated by the contact area of the tire on the ground during a taxi. In all cases, the invention aims and achieves a high measurement accuracy and an excellent resolution, compared to

  previous technologies that could be advocated.

  It will be understood that the term "resolution" aims at a better localization of the effort, whereas the term "precision" aims at a

  better accuracy of the measurement of this effort.

  By "true cartography" is meant in the present application a technology according to which the components of the forces are separated along the three axes x, y, z, (x and y defining, in a ground application, the plane of the track for example) and is positioned instead of their generation at the contact area or more generally the "area of effects." Thus, according to the invention, the effort is measured. the effect on the place where it is generated, which poses on the other hand big problems or is not solved in the technologies recommended previously Summary of the invention The device according to the invention, or the corresponding method, makes it possible to perform a true three-dimensional mapping of ground effects, as described above, and in particular, in a particular non-limiting embodiment, to locate the contact area of the tire and its precise contour by optical measurement through a prism or porthole or the like then (or in reverse order) to map the efforts

  created on the ground by the tire.

  The device according to the invention also makes it possible to establish a measurement and then a mapping of the three-dimensional forces generated by the contact area of the tire on the ground during a taxi, using two main sources of information, which are a matrix of sensors

  combined with image capture, and a final treatment.

  The method and the device according to the invention, for performing a mapping of effects (including efforts, with or without "contact") three-dimensional x, y, z generated on the ground by the passage of one or at least a part of such an object or vehicle ", and in particular by at least one tire or more generally a tread of this vehicle, is characterized in that it comprises: * a matrix of sensors, of length generally less than area of "ground" or "ground" contact in the longitudinal direction, composed of mono-, di-, and / or

  three-dimensional, preferably three-dimensional.

  means for characterizing the shape and location in the ground reference, for example an image acquisition or a set of sensors adapted to a shape characterization, in particular a set of distance sensors, at the level of the zone or "area" "o are the effects or forces, allowing the location of a given part of the" vehicle or object "relative to a ground reference, including, without limitation, at the contact area of at less a tire or more generally at least one tread, allowing the location of the wheel relative to a

landmark.

  an appropriate processing means (of known type based on electronics and computers) using or integrating or taking into account the relationship between the effect created and the shape of the object or

  vehicle or part thereof having generated said effect.

  It will be understood that the "longitudinal direction" designates the axis of the track

  test or axis of vehicle advance on the test track.

  The device and method according to the invention can also be applied to a test device called "rolling" (it is a rotating cylinder, which drives a tire positioned in contact (or vice versa). Those skilled in the art will understand that the invention applies mutatis mutandis to this use, and that the longitudinal direction then designates, to take only this example, the relative axis of advance of the

pneumatic on the rolling machine).

  This solution (roller mounting) allows to control the position of the tire with respect to the different force sensors, on the other hand, using encoders positioned on the axis of the wheel and the hub of the wheel under test. it is also possible to control the azimuth of the tire with respect to said sensors. This mastery can then be used to dispense with performing the

  optical visualization of the contact area.

  In addition, it makes it possible to achieve the minimum number of measures to obtain all the necessary measures for reconstruction.

of the contact area.

  A drawing (Figure 2) corresponding to such use is provided below.

  after. By "location" of the wheel (in the particular case considered), it is understood inter alia, when it is a measurement relating to a wheel or a tire, the determination of the wheel azimuth and the positioning of the wheel. wheel in the ground reference in x and y (possibly z). It is recalled that the wheel azimuth is the angle formed between a mark fixed on the wheel and a fixed angular reference mark, for example the ground or a parallel ground. The wheel azimuth gives a precise indication of the rotation of the wheel. When it is not a tire or a wheel, for example "aero" or "hydro" measurement on an airplane wing, etc., the "location" consists in determining the position in the ground reference x, y, z, of the object or vehicle (note that, when a measurement is taken on a tire, it is also possible to "locate" the tire directly by a track edge measurement or the like , as will be indicated below, without going through the determination of the azimuth). It should also be noted that the term "characterization of form", often appended to the word "localization", refers to the determination of the shape of at least a part of the object or vehicle, in relation to the measurement to be made. As will be said below, we use means

  measurement "edge of the track" (3D etc ...).

  "x" refers to effects or forces in the longitudinal direction, "y" in the lateral or transverse sense, and "z" in the vertical direction (pressure effect). According to the general definition of the invention, the sensor array is of any shape and consists of sensors or any combination of sensors, including, but not limited to, pressure and / or stress sensors (optionally different types and / or

  possibly in combination with other categories of sensors).

  According to a particular embodiment, it consists of at least one bar of pressure sensors inserted on the ground, or of sensors placed in a non-symmetrical manner, or of a cloud of sensors and variations.

  analogues which will become apparent to those skilled in the art.

  It will also be possible to use a matrix composed of several different matrices (in terms of shape, sensors, arrangement of the sensors, etc.), in a manner directly accessible to those skilled in the art, adapted to their particular needs dictated by the object and the type of measurement. A replacement of the force sensors by pressure sensors makes it possible, for example, in a hydrodynamic environment (presence of a liquid on the track in the measurement zone), to establish a map of the pressures in the tire tread pattern. to deduce the flow velocities of the water in the channels of the sculpture (application of the Bernoulli formula P + pgz + 1 / 2pv2 = cte) As an application of this particular embodiment, mention may be made of obtaining, in an aerodynamic environment (that is to say, the same process used in air or a gas or on a dry runway), a real mapping of the ground effects generated by the passage of the "vehicle" This "aero" system can be inserted either in the ground or above ground (for example, and without limitation, on a gantry carrying sensors and disposed above the measurement zone). application lies for example in the measurement of the effect of passing a wing fin of competition, or an aircraft wing, or any other aerodynamic part, with a "laminar cut" (as in a wind tunnel, but with

  decisive advantages over wind tunnel tests mentioned above.

  below). In all cases, the sensors (in the form of a "bar", "cloud" or the like) can be fixed and the moving object or vehicle, or vice versa (vehicle or fixed object and mobile sensors with respect to in particular in the "longitudinal direction", for example to study the ground effect of an aircraft wing in aerodynamic wind tunnel, or a

  hull of ship in hull basin, and the like).

  In the case where the positioning of the sensors is not longitudinal, it is possible to have access to measurements of forces or effects on the ground of a vehicle or object in a turn, which will very advantageously replace the current measurements made in the wind tunnel. measurements are made at an angle of the order of 10-15 compared to the longitudinal direction, for

  very partially simulate a turn.

  The advantage of the invention is naturally that, unlike the use of wind tunnels, measurements are made on a vehicle or real object (and not a model) and in real conditions of displacement

(including the surrounding context).

  Detailed description of the invention

  The method according to the invention comprises two steps 1 measurements 2 reconstitution of an area of effects on the ground or possibly of

contact.

  The method of obtaining a contact area map or more generally of efforts or effects, with or without contact, aims to assign to each coordinate point Px, Py ("<positioning") and possibly Pz of the area of effort or effects or contact the forces

  Fx, Fy, Fz generated by contact, effect, or effort.

  The difficulty of the problem comes precisely, and this has not been solved in the prior art, to achieve this "true" mapping and not average measurements according to different wheel azimuths, or

  "localizations" different, or approximations etc ....

  The invention relates to a method (and the corresponding device) for mapping - effects (whose forces, with or without "contact") three-dimensional Fx, Fy, Fz - generated at each point i (xi, yi, zi). of an "area," "on the ground", said area being able to consist of a single area or on the contrary of several fragmentary areas, and forming one or more surfaces established on the ground, the "ground" possibly being the seabed, a hull basin, a test track, a road and the like, and / or above the test area, and / or laterally thereto, under one or more orientation (s) any of any shape (s) adapted to the relevant measures, hereinafter "area" and respectively "ground" for simplicity, - by the passage of one or at least a part of a " object or vehicle ", * and in particular, in the" contact "measurement mode, at least one tire of a wheel or more generally a tread of this" object or vehicle ", * and / or in particular at least one aerodynamic or hydrodynamic element of this" object or vehicle ", in" aerodynamic or hydrodynamic "measurement mode, on, above, below or in the vicinity of "area", characterized in that it comprises two main steps: 1 measurements of effect parameters in the "area" "on the ground" by A At least one matrix of sensors, generally of length and / or width those of the ground effect area (with or without contact), in the longitudinal direction (that is to say of passage) or not, and composed of effort sensors, identical or not, and mono -, di-, and / or three-dimensional, preferably three-dimensional, * B possibly form characterization means and / or localization in the ground reference (that is to say relative to a reference of the area of test or in particular of the area), for example an image capture and / or a set of sensors adapted to a particular character. form and / or location, in particular a set of distance measuring sensors, at the level of the zone or "area>" where the effects or forces are felt, allowing the location of a determined part of the <vehicle or object "with respect to a ground reference, 2 reconstitution of an area of effort mapping (of" ground "effects or possibly of" ground "contact) by an appropriate means of treatment using or integrating or taking into account the relation between the created effect (1 A) and possibly the shape of the object or

  vehicle or part thereof having generated said effect (1 B).

  According to one embodiment, the sensor array consists of sensors or any combination of any sensors, including pressure sensors and / or effort (possibly of different types and / or possibly in combination with other

categories of sensors).

  According to another preferred embodiment, the sensor array consists of at least one array of pressure and / or force sensors, such sensors being placed in a non-symmetrical or symmetrical manner, and / or at least one a cloud of such sensors or combination of such sensors, inserted in the "area", (ie "ground" and / or on one or more support (s) out ground as a gantry placed above the test area or one or more lateral support (s) of any orientation (s), shape (s) and arrangement (s)

any spatial (s)).

  According to a preferred embodiment, the sensors (in the form of a "bar", "cloud" or the like) can be fixed and the mobile object or vehicle, or the opposite (vehicle or fixed object and mobile sensors by in particular in the "longitudinal direction") or in that the sensors and the object or vehicle are movable from

  any way with respect to each other.

  According to a preferred embodiment, the means (1 B) for determining the shape and / or location of the object or vehicle, or at least part of it, in the "ground" reference, are selected from at least one camera inserted in the "ground" behind one or more portholes and / or prisms and / or other transparent devices, and / or inserted in the ground or above ground, for example on the edge of the area, among diodes or diode matrices, and / or photogrammetric and / or stereophotogrammetric means, and / or among distance measuring sensors, preferably non-contact sensors (ultrasonic sensors, laser, optical triangulation, optical analysis of the deformation of 'a projected network, projection of fringes, 3D sensors), functioning in visualization

  snapshot of the entire object, or scan the object.

  A particular mode of implementation of the method and the device according to the invention will be described below in conditions called "aerodynamic" or "hydrodynamic", that is to say by passing an object or vehicle overhead / neighborhood of a "surface" to "soil", in a medium such as a fluid such as water, air, a gas, an aqueous or non-aqueous fluid, and the like, without contact of the object with the area, for simplification

<< AERO MODE

  Summary: The proposed device (and method) makes it possible to qualify the aerodynamics of a vehicle or object, in rolling or not, and particularly of

  dissociate the ground effect from the rest of the aerodynamics of the vehicle.

  It also allows in-depth analysis of the mapping of pressures and depressions and air velocities under and to

around the vehicle.

Description:

  The device consists of a bar of pressure sensors inserted in the ground, placed substantially perpendicular to the axis of the vehicle. The sensors that make up the bar are spaced apart by a distance between zero and a few hundredths of a millimeter or a few centimeters (or a few tens of centimeters or more, especially for wind tunnel measurements, of the order of 20 to 30 cm) and are preferably positioned aligned, staggered or V, head to tail, etc .... They are preferably flush with respect to the upper part of the bar, but can be recessed or exceed

  slightly as needed.

  The device ("barette") can also be composed of a cloud of sensors, of several clouds, of several bars, or combinations of these formulas, possibly successively in the direction

  longitudinal, and / or in the transverse and / or vertical direction.

  As indicated above, these combinations can be spatially distributed according to the tests to be carried out.

  During the passage of the vehicle or object, an acquisition is made on all the sensors of the bar (the word "bar" being taken

  in the present application in its broad sense stated above).

  This acquisition can start a few meters before the passage of the vehicle, and can end a few meters or tens of meters

after the passage of the vehicle.

  The acquisitions thus made make it possible to establish a map of the pressures and depressions measured on the ground during the passage of the vehicle, in the case of pressure sensors, or other parameters depending on the nature of the sensors. It will also be possible to combine different types of sensors, such as a pressure sensor strip and a distance sensor strip, the latter making it possible, for example, to measure the height of a vehicle chassis, and similar combinations. If the sensors are not aligned perpendicularly to the centreline of the runway or substantially in relation to the forward axis of the vehicle, a time registration may be performed to align

"virtually" acquisitions.

  From the measurement of the speed and the acceleration of the vehicle and the plane of the vehicle seen from below, it is deduced at each moment of the acquisition, the position of the contact areas of the tires of the vehicle, this allows to exclude from measurement and mapping surfaces corresponding to the contact areas of the tires. These measurements are advantageously supplemented by measurements of longitudinal, transverse and vertical forces on each

  wheels from measuring blocks inserted into the ground.

  These last measurements are made under the same conditions as the previous ones and make it possible to deduce by subtraction of the depression forces measured on the ground, and the static loads of the vehicle the essential elements of the aerodynamic forces generated by the upper part of the vehicle (Global efforts measured on the wheels = ground effect + static loads, + dynamic inertia + aerodynamic load

  median and upper parts of the vehicle).

  It is deduced from this: The mapping of the ground effect of the vehicle, the overall efficiency of the soil effect, its distribution, the position of the barycenter of the depression with respect to the vehicle, the characteristics of the front of the vehicle. wave upstream of the vehicle including in particular the intensity, * the air velocities between the vehicle and the ground, 10. the characteristics of aerodynamic drag downstream of the vehicle including the intensity, aerodynamic effects their overall efficiency, their distribution by wheel, the position of their barycentre with respect to the vehicle, the aerodynamic effects generated by the upper part of the vehicle, the overall efficiency of these aerodynamic effects, their distribution by wheel, the position of their center of gravity relative to the vehicle. In a similar vein, if the pressure sensors are replaced by distance sensors, as specified above, it is possible to measure chassis, bodywork, flat bottom or any other geometries.

  other element attached to the vehicle.

  We can naturally combine the two means of measurement.

  Similarly, the aforementioned devices can be used above ground to measure pressure maps (and / or geometries in space, in order to possibly correlate the two

  measurements) of an object during its passage.

  In the latter case, in particular, the sensor array or the cloud of

  sensor can be three-dimensional.

  In a major variant substantially improving the interpretation of the measurement results, the pressure measuring method will be completed by a second measuring method: This second measuring method can take two forms (the

  combination of the two forms being also possible).

  According to the first form, the method will consist of a visualization means of the object generating the pressure or the depression (also

  referred to here more generally "effects" as specified above).

  For this purpose and in the configuration where the means is inserted in the "ground", cameras will be inserted in the track or other "ground", or under one or more transparent portholes. The cameras will allow either an instantaneous visualization of the entire object, or a scanning of the object, the latter advancing into the field of cameras (here we can use linear cameras or matrix cameras ). This global method makes it possible to have the cartography of the effect created on the ground superimposed on the two-dimensional shape of the object

generating this effect.

  According to the second form, the method will consist of preferably non-contact distance measuring sensors (ultrasonic sensors, laser, optical triangulation, optical analysis of the deformation of a projected network). As before, the sensors will make it possible to perform a bi or three-dimensional instantaneous measurement of the entire object, or to perform a scanning of the object, the latter advancing in the field of the sensors. This global process makes it possible to have the cartography of the effect created on the ground superimposed on the shape

  tridimensional of the object generating this effect.

  This major variant makes it possible to have the aerodynamic effect generated as well as the shape of the object which can be for example a

  fin or underbody of a competition vehicle.

  We can also deduce with the aid of this complete device the

  deformations of the object generated by the aerodynamic effects.

  This type of device can also be used in the aeronautical and naval fields (in particular during wind tunnel or basin tests where the cloud of sensors must be moved relative to the model, the latter not advancing) ADVANTAGES of the invention in "AERO" mode: To date, there is no way to perform real mapping of

  effects on "ground", aerodynamic or hydrodynamic.

  The device of the invention requires only a small number of sensors, and is therefore reliable and low maintenance cost. It makes it possible to relate the effect measured to the ground to the characteristics of the object (thus connecting the shape and the effect of the shape to the ground) such as the shape and the associated effect of a vehicle underbody, a fin of

  competition vehicle of the Formula 1 type, and the like.

  It also allows to measure the deformation of the object created by the effect on the ground itself, that is to say the deformation of the object "induced" by its own passage. In this case, it suffices to compare the map obtained according to the invention with a reference form, namely

  the object at rest, either theoretical or modeled form.

  The invention allows measurements whose quality is at least equal to the measurements made in the wind tunnel, with the decisive advantages of not being dependent on the proximity of a wind tunnel, not being dependent on models or the preparation of tests, to be able to be repeated many times without constraints, and to take into account the real conditions of displacement of a real object, on a real measurement area, and the real environment (in a wind tunnel, the flow is too "clean" that is to say that the flow is too laminar, on the contrary, the invention makes it possible to integrate the effects of the inevitable turbulences and hazards of the medium in which the object moves, and true

"floor" scrolling).

  It is also possible to combine several parameters, for example longitudinally moving ground mapping while subjecting the test area to a "cross" or face or back wind (impossible or unrealistic tests in the wind tunnel, and in any case impossible to interpret), and similar conditions, which makes it possible to measure the effect of such a wind across, face, back, oblique, ..., on a vehicle, an airplane (phase simulation landing or takeoff) etc ...

  Detailed description of the "aero" mode

  According to this mode, the invention relates to a method (and a corresponding device) as described above, characterized in that one operates in an aerodynamic or hydrodynamic environment (implementation of the process in the air or a gas or other fluid as a liquid such as water) and real cartography of the effects generated on the "ground" by the passage of the "vehicle" on or

  neighborhood of the area or "area" of measurement.

  It will be understood that, throughout the application, the description of the

  , method "also gives the description of the" device "

  corresponding, without the need to duplicate all

descriptions.

  According to a preferred embodiment, the invention relates in this mode "aero" a method characterized in that one operates in a hydrodynamic medium, especially in water, the measuring means 1A being placed at the seabed, or on the bottom or around a basin of

  hull, pool, pool and the like.

  According to this same mode, the invention also relates to a process characterized in that one operates in an aerodynamic or hydrodynamic medium, especially in water, the measuring means 1A being inserted into a track or a gantry, a tunnel, a moving floor of

wind tunnel and the like.

  According to a further preferred embodiment, the invention relates to a method for obtaining a map of "<area" of forces or effects generated on the "ground," by the passage of an "object or vehicle "or at least a part thereof, without contact, intended to assign to each coordinate point Px, Py, Pz (" positioning ") of the area of effort or effects or contact, the forces Fx, Fy, Fz generated precisely at this point by the effect or the force, characterized in that: - at the level of an area of effects or efforts, composed of points of coordinates (Pxi, Pyi ), there is a matrix of k means for measuring the forces (Fxi, Fyi, Fzi) generated at each point i by the passage on or in the vicinity of this area of an object or vehicle, or at least a part of it, without contact, in particular a matrix of k force sensors, preferably three-dimensional, Measures 1 - measurements are made (1A) by said means ci (by a passage of the veh icule or object on said and / or in the vicinity of said means ci) for accessing the magnitudes (Fxi, Fyi and Fzi) (t) (measured directly by said means) is carried out on the one hand effort measurements (measurements 1A) with the aid of a matrix of k effort sensors, preferably three-dimensional; * the effort measurements are made during the entire passage of the vehicle or object on or in the vicinity of said matrix, or for a period of at least (L + 1) / v with: L: Length of the area of ground effects I1: Length of the sensor matrix v: Vehicle advance speed or object * each sensor ci with (i <k) thus delivers at the acquisition time t all of the following data: Fxi ( t), Fyi (t), Fzi (t) respectively corresponding to the forces measured at time t by the sensor ci along the longitudinal axis of the reference mark

  (usually the ground or track mark), the transverse axis and the vertical axis.

  * we then obtain a database of triplets of effort measurements of k columns and at least (L + 1) * F / v lines with F acquisition frequency (the columns corresponding to the different sensors, the lines corresponding to the different instants t of acquisition) * is carried out on the other hand (measurement 2B) - using at least one means ML of image-taking type location, or edge of track or an onboard locating means on the vehicle (or a combination of these means) a spatial location in x, y, z of the area of effect and / or (depending on the means ML) of the object or vehicle at a time t ' which is the instant of said location, t 'being (possibly) different from t due to the spatial shift (if any) between the sensor ci and the ML means of localization - it then deduces its coordinates (in the reference reference) which we will call Px (t ') Py (t') Pz (t ') - as we know Px (t'), Py (t ') and Pz (t') at time t 'and that we knows the equation of the movement or the speed of advancement of the object or vehicle, substantially its direction, or its direction (angle / longitudinal axis), according to the means ML used, and the positioning of each sensor ci of the matrix d effort in the reference frame and the positioning of the locating means ML in this same frame; we are able to determine Pxi (t), Pyi (t), Pzi (t) corresponding to each of the triplets of forces Fxi (t), Fyi (t), Fzi (t) measured by the sensor ci at the instant t; a database of sextuplets of effort measurements, of k columns and (L + 1) / v lines is then constituted: (Fxi (t), Fyi (t), Fzi (t), Pxi (t), Pyi (t), Pzi (t)) O the columns corresponding to the different sensors, and the lines corresponding to the different instants t of acquisition Reconstitution 2 of the effects area in the "ground - one wants a real mapping of the efforts or effects F corresponding to each point x, y, z of the area of effects in "ground - so we extract from the previous database all sextuplets corresponding to this point that is to say such as x, y , z (j) (t) = x, y, z with (j <k) we then position each effort triplet Fxi (t), Fyi (t), Fzi (t) at the coordinate point Pxi (t) , Pyi (t), Pzi (t) of the area, and - one thus constitutes the cartography of the efforts generated at the level of

  the area of effects at <ground "at each point x, y, z of the area.

  The invention also relates to a method of the type described characterized in that it also performs a measurement of forces by contact at "ground" and deduced, by subtraction of the forces measured on the ground, and the static loads of the vehicle or object, the essential elements of aerodynamic or hydrodynamic forces generated. We will now describe below the particular method of the general type above (and therefore, according to the convention established, the corresponding device), corresponding to a measurement of forces generated on an "area" at "ground" by a contact, such as for example the contact of a wheel or a tire or a tread on a track, or a fingerprint on a recording block of the imprint, or the coc of a tennis ball on a ground measurement area, and other applications already indicated, either for simplification

<< CONTACT MODE >>

  According to this particular embodiment, the invention relates to a method, of the general type described above, for obtaining a map of "<area"> of contact generated at "ground"> by the passage of a "object or vehicle" or at least a part thereof, with contact, for assigning to each coordinate point Px, Py, Pz ("positioning") of the contact area, the forces Fx, Fy, Fz generated precisely at this point by the contact, characterized in that: - at the level of a contact area or effects or efforts, composed of coordinate points (Pxi, Pyi, Pzi), a matrix of k means for measuring the contact forces (Fxi, Fyi, Fzi) generated at each point i by the passage over this contact area of a tire or tread of an object is available or vehicle, or at least a part thereof, in particular a matrix of k force sensors, preferably three-dimensional, Measurements 1 - measurements are made (1A) by said means ci (by N successive passages of the vehicle or object on said means ci) for accessing the quantities (Fxi, Fyi and Fzi) (t) (measured directly by said means) - at the passage n (with n <N) on performs on the one hand force measurements (measurements 1 A) using a matrix of k effort sensors preferably three-dimensional; * the effort measurements are made during all the contact between the matrix and the contact area of the tire, ie for a duration of at least (L + 1) / v with: L: Length of the contact area : Length of the sensor matrix v: speed of advance of the tire or the wheel or of any tread * each sensor ci with (i <k) thus delivers at the time of acquisition t the set of data following F xi (t), Fyi (t), Fzi (t) respectively corresponding to the forces measured at time t by the sensor ci along the longitudinal axis of the reference mark (usually the ground reference or track), I ' transverse axis and the vertical axis; for the passage n, we obtain a database of triplets of effort measurements of k columns and at least (L + I) * F / v lines with F acquisition frequency (the columns corresponding to the different sensors, the lines corresponding to the different instants t of acquisition) * one carries out on the other hand (measurement 2 B) - using at least one ML means of location of the camera and prism type, or diodes or matrix of diodes, or means of tracking on the vehicle (or a combination of these means) a spatial location and an azimuthal location of the contact area and / or wheel, tire, tread, according to the ML means employed, at a time t 'which is the instant of said location, t' being (possibly) different from t due to the spatial shift (if any) between the sensor ci and the ML means of localization - it is then deduced its coordinates (in the reference frame) which will be called Px (t ') Py (t ') and Pz (t') and its azimuth alpha (t ') - as we know Px (t'), Py (t '), Pz (t') and alpha (t ') at the instant t' and that the equation of the movement of the tire, wheel or tread, or the speed of advancement of the object or vehicle, substantially its direction, or its direction (angle / longitudinal axis) is known according to the average ML used, and the positioning of each sensor ci of the force matrix in the reference frame and the positioning of the locating means ML in this same frame; it is possible to determine Pxi (t), Pyi (t) and alpha i (t) corresponding to each of the triplets of forces Fxi (t), Fyi (t), Fzi (t) measured by the sensor i to moment t; Pxi (t) and Pyi (t) being the coordinates of the effort triplet in the mapping of contact area corresponding to the azimuth ocd (t); then, for each passage n, a data base of seven tens of force measurements, k columns and (L + 1) / v lines: (Fxi (t), Fyi (t), Fzi (t), Pxi (t), Pyi (t), Pzi (t) and alpha i (t)) (n) the columns corresponding to the different sensors, and the lines corresponding to the different instants t of acquisition Reconstitution 2 of the contact area - we want a true mapping of the forces or effects F corresponding to a given azimuth alpha, the wheel, the tire or the tread on the contact area - we thus extract from the previous database constituted from the N passages every septuplets corresponding to this azimuth that is to say, such that alpha (j) (t) = alpha with (j <k) we then position each triple of effort Fxj (t), Fyj (t), Fzj (t) at the point of coordinates Pxj (t), Pyj (t), Pzj (t), and o - we thus constitute the cartography of the three-dimensional forces

  generated at the contact area along a chosen alpha azimuth.

  The invention also relates to a method characterized in that the measurement of the azimuth alpha i is carried out at each passage n: - by a photograph taken through at least one prism on which rolls the wheel or tire (or any tread) before or after its passage over the area of contact (or possibly during) o are the measuring means, after which alpha i (at the area level) is deduced from the determined azimuth alpha p at the level of the prism (or any other means of determination of the azimuth), by one of the following methods: - if the distance between the measurement at the level of the area and the measurement at the level of the prism corresponds exactly to a lap of wheel, no correction is necessary, the alpha p measured with the prism being hypothetically identical to the alpha i measured at the level of the area; if said distance does not correspond to a wheel revolution, a correction is made by simple and known geometrical means, or by the analysis of the data provided by a visual, magnetic or similar coder capable of measuring the alpha p at the level of the prism and the alpha i at the level of the measurement area, the prism thus giving the information Pxi, Pyi, Pzi at each passage; (Possibly, if, with complications of setting up the measuring devices, it is possible to determine the azimuth exactly in the same place where the measurement is made, this correction from alpha p to alpha i is of course useless. ) or by "trackside" measuring means such as 3D sensors, and / or on-vehicle means such as optical, magnetic and similar encoders, etc., giving a reference at the level of the measuring area, the prism giving the information

Pxi, Pyi, Pzi as above.

  As already indicated, the photograph concerns the measurement area, with ("efforts") or without (, "ground effects",) contact, and in the latter case for example measurement of the ground effects of a wing, d a vehicle body underside, etc .... it will also be understood that "<ground effects" also refers to the effects "above ground" when, in the variant described above, at least a portion of the sensors is placed

  on a gantry or analogous ground support.

  It is also possible to carry out, as an optional option, a "shape" characterization of the object passing over the measurement zone, for example by optical scanning of the object or else 3D measurements by means of distance sensors (from ultrasonic type, laser, by

  optical triangulation, well known to those skilled in the art).

  The invention also relates to a method characterized in that Pxi, Pyi and Pzi are directly determined by means of edge-of-the-wall measurement, for example by projection of a fringe network or analysis.

  photogrammetric and / or stereoscopic.

  If at the same time there is a track edge means giving access to Px and Py, and possibly Pz, and a track edge means giving the azimuth at the measuring point, the photograph by the prism n ' is

more necessary.

  As will be seen below, the prism nevertheless gives valuable additional information in many applications. The invention also relates, according to a particular embodiment, to a method characterized in that, in a hydrodynamic environment (presence of a liquid on the track in the measuring zone), a mapping of the pressures in the tire tread is established. , and we deduce the flow velocities of the water in the channels of the

  sculpture (application of Bernoulli's formula P + pgz + 1 / 2pv2 = coast).

  The invention also relates to a method of the type described above, applied to the particular case of smooth tires or tires without variation of longitudinal pattern (for example tires of Formula 1 grooved longitudinally), according to which we can consider that all the azimuths are identical , characterized in that all the measurements correspond to the desired azimuth for the cartography, which makes it possible to dispose more quickly of all the data necessary for the establishment of this cartography, and thus to reduce the number of passages until to a small number typically three and even

  possibly a passage (because the patterns are identical).

  The invention also relates to a method of the type described above, characterized in that there are sensors of sufficient transverse resolution to overcome the determination of the azimuth, and perform

a measure of effort alone.

  The invention also relates to a method of the type described above, applied to the particular case of pneumatic tires with longitudinal repetitive patterns, characterized in that the mapping of the forces generated by a pattern during its crossing of the contact area is measured and makes a sufficient number of passages to arrange the different azimuths, all the information is available to reconstruct a complete mapping of the contact area along any azimuth, and the contact area is reconstructed from the measurements taken. on an integer pattern seen by the sensor array and corresponding to the azimuth o (x to which the integer patterns corresponding to the azimuths oc + k * P are joined with 3 corresponding to a pattern length L seen from the wheel center (L < "R so f L / R with R

  crushed tire radius) and k positive or negative integer.

  The invention also relates to a method of the type described above, applied to the particular case of tires with repetitive patterns, characterized in that said repetition is used considering that a pattern is equivalent to the following modulo a length equal to the length of this pattern (or a time equal to the length of the pattern divided by the speed

  progress of the wheel or the tire).

  The invention also relates to a method of the type described above, applied to the particular case of tires with a repeating longitudinal pattern but of variable length, characterized in that the motive is no longer the basic pattern, but all the patterns. basis of a cycle of variation in the length of this basic pattern, account is taken of the fact that the forces generated in the contact area vary greatly only in the edges and edges of the tread patterns, the pitch variations of the patterns, as well as the azimuth of the measurement (or we have the image of the surface of the contact area on which the measurement was made, for example by a camera under prism) and completely restores the contact area by moving from a "long" bread to a "short" bread, using for this the same contour (this contour having the width of the sensor of the matrix taken in the direction perpendicular to the advancement of vehicle and for length the length of the sensor of the matrix taken in the direction of advance of the vehicle), and integrating the fact that at the same spatial positioning Ca = Cc and Cb = Cd and that CO = C1 and CO = C2

  at iso-positioning (that is, at identical positioning).

  that is to say, we can reconstruct a complete mapping of contact area according to any azimuth by spatial and then temporal repositioning from the knowledge of the development of the tread of the tire and the complete measurement of a pattern of

based.

  We will now describe below, in more detail, the processing of the image obtained. Treatment The invention further relates to a method of the type described above, characterized in that the treatment is divided into three phases: 1 Cleaning and straightening the image 2 Extraction of the contact area 3 Extraction of the coordinates of the area of contact and corresponding azimuth in that the rectification is made from a calibration carried out upstream of the measurements and which implements a calibrated target which is applied on the upper surface of the prism, the contact zones of this mire being preferably made of a flexible material (for example elastomer) in that the calibration is carried out either upstream of the measurements, or during the measurement phase or between measurements from departicularities performed on the upper face of the prism (for example the grooves used to increase the contact pressure or engraved crosses or elements or inserts reported) in that the extraction of the contact area is carried out automatically or manually and in that the coordinates of the contact area are extracted by initial calibration with the aid of a reference standard identified in the track reference system, which makes it possible to assign to each point of the image of the coordinates in this reference ground; then we evaluate the coordinates of

  the contact area in the ground reference.

  The invention also relates to a method of the type described above, characterized in that a shooting is carried out without object or vehicle placed on the prism and corrections are made on this image and then automatically applied to the following measures, by performing possibly a subtraction of the image in treatment by

  the initial image made without object placed on the prism.

  The invention also relates to a method of the type described above, characterized in that the measurements (1A) are completed by measurements of longitudinal, transverse and vertical forces carried out on each

  wheels from measuring blocks inserted into the ground.

  Prism alone According to a particular mode of implementation, the invention comprises a method as described above and characterized in that only an image of the contact area to which one is interested is made, through a prism operating in total reflection, that is, whose angle

alpha is> = 45.

  The device according to the invention will be described in more detail below, it being understood, as will be understood by those skilled in the art, that a part

  of the description has already been indicated in the context of the

  description of the process, which it will not always be necessary to

duplicate.

DEVICE

  The present invention also relates to a device for mapping - effects (whose forces, with or without "contact") three-dimensional Fx, Fy, Fz - generated at each point of an "area," "on the ground" (c 'ie on a surface established on the ground, the' ground ', which may be the seabed, a hull basin, a runway, a road and the like), be placed above the test area , or laterally with respect thereto, under any orientation or orientations and of any shape adapted to the measurements concerned, hereinafter "area" and respectively "ground" for simplicity), - by the passage of one or at least a part of an "object or vehicle", * and in particular, in the "contact" measurement mode, of at least one tire or, more generally, a tire strip; rolling of this "object or vehicle", * and / or in particular of at least one aerodynamic or hydrodynamic element of this "object or vehicle", in measuring mode "aerodynamic or hydrodynamic", * on, above, below, or in the vicinity of said "area", characterized in that it comprises * A At least one array of sensors, of length generally less than the area of effects on the ground or contact, in the longitudinal direction (that is to say of passage) or not, and composed of force sensors, identical or not, and mono-, di-, and / or three-dimensional, of preferably three-dimensional, * B possibly a means of characterization of shape and location in the ground reference (that is to say relative to a reference of the test area or in particular the area), for example a image taking or a set of sensors adapted to a shape characterization, in particular a set of distance measuring sensors, at the level of the zone or "area" where the effects or forces are felt, allowing the location of a particular part of the "vehicle or object" in relation to a ground reference mark, In particular, the invention relates to a device of the type described above, characterized in that it comprises an appropriate means of treatment adapted to the reconstruction of a mapping of the area of the forces (effects to "ground" or possibly contact at "ground") using or integrating or taking into account the relation between the effect created (1 A) and possibly the shape of the object or vehicle

  or part thereof having generated said effect (1 B).

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that the sensor array consists of sensors or any combination of any sensors, including pressure sensors and / or effort (possibly of different types and / or possibly

  combination with other sensor categories).

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that the sensor array consists of at least one array of pressure sensors and / or forces, such sensors being placed unsymmetrically or symmetrically, and / or at least one cloud of such sensors or combination of such sensors, inserted into the "area" (i.e. , ground "and / or on an above-ground support such as a gantry placed above the test area or a lateral support for orientation

  whatever, and of any shape (s) and spatial arrangement (s).

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that the sensors (in the form of "bar", "cloud" or other), can be fixedly mounted while the object or vehicle is mobile, or the opposite (vehicle or fixed object and movable sensors relative to him in particular in the longitudinal direction ") or in that the sensors and the object or vehicle are mobile in any way l With respect to a particular embodiment, the invention relates to a device of the type described above, characterized in that the means (1 B) for determining the shape and / or location of the object or vehicle, or at least part of it, in the "ground" mark, are chosen from at least one camera inserted into the ground "behind one or more portholes and / or prisms and / or other transparent devices, and / or among sensors for distance measurement, contactless (ultrasonic sensors, laser, optical triangulation, optical analysis of the deformation of a projected network, 3D sensors, photogrammetric and / or stereoscopic analysis), operating in instantaneous visualization of the entire object, or in scanning of the object and / or means embedded on the vehicle as optical encoders

magnetic and the like.

  Particular device in AERO mode According to a particular embodiment, the invention relates to a device of the type described above, for obtaining a map of "area" of efforts or effects generated in the "ground" by passing an "object or vehicle" or at least a portion thereof, without contact, for assigning to each point of coordinates Px, Py, Pz ("positioning") of the area of 'forces or effects or contact, the forces Fx, Fy, Fz generated precisely at this point by the contact, the effect or the force, characterized in that: - at the level of a contact area or 'effects or forces, composed of points of coordinates (Pxi, Pyi, Pzi), - the means of measuring the forces (Fxi, Fyi, Fzi) generated at point i by the passage on or in the vicinity of this area are available of an object or vehicle, or at least part of it, without contact, According to a particular embodiment, the invention relates to a device of the type described herein. above, characterized in that one has

  more means for measuring forces by "ground" contact.

  Particular device in CONTACT mode According to a particular embodiment, the invention relates to a device of the type described above, for obtaining a map of "<area", efforts or effects generated at < "ground" by the passage of an "object or vehicle" or at least a part thereof, with contact, intended to assign to each coordinate point Px, Py, Pz ("positioning") of the contact area, the forces Fx, Fy, Fz generated precisely at this point by the contact, the effect or the force, characterized in that: - at the level of a contact area or effects or efforts , composed of points of coordinates Pxi, Pyi, Pzi - there are means for measuring the forces generated by the passage on this area of an object or vehicle, such as a wheel, a tire, etc ..... - as well as means for measuring the azimuth alpha i at each passage: by a photograph taken through at least one prism on which the wheel or tire rotates. (or any tread) before or after its passage over the contact area where the measuring means are located, after which alpha i (at the area level) is deduced from the azimuth alpha p determined at the of the prism, by one of the following methods: - if the distance between the measurement at the level of the area and the measurement at the level of the prism corresponds exactly to one turn of the wheel, no correction is necessary, the alpha p measured at prism being hypothetically identical to the alpha i measured at the level of the area; if said distance does not correspond to a wheel revolution, a correction is made by simple and known geometrical means, or by the analysis of the data provided by a visual, magnetic or similar coder capable of measuring the alpha p at the level of the prism and the alpha i at the measurement area, the prism thus giving

  information Pxi, Pyi, Pzi at each pass.

  or - by means of "runway edge" measuring means such as 3D sensors, optical, magnetic and similar coders, embarked on the vehicle, giving a reference to the level of the

  measure, the prism giving the information Pxi, Pyi, Pzi as above.

* General description of the device. in aero mode and / or contact

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that there are means for measuring the edge of the track, for example by projecting a network of fringes, able to determine directly Pxi, Pyi and Pzi According to a particular embodiment, the invention relates to a device of the type described above, characterized in that the positioning of the sensors is generally not longitudinal, and in particular that the positioning is substantially

  perpendicular to the axis of the object or vehicle.

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that the sensors that make up the bar or bars are spaced apart by a distance of between a few hundredths of a millimeter and a few centimeters. and are preferably aligned, staggered or V-shaped, head to tail, etc. ...., are preferably flush with respect to the upper portion of the bar, but may be recessed or slightly exceed. According to a particular embodiment, the invention relates to a device of the type described above, characterized in that the device comprises at least one cloud of sensors, several clouds, several bars, or combinations of these formulas, possibly successively in the longitudinal direction, and / or in the transverse direction (relative to the direction of advancement of the object, or movement

relative object / area).

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that it combines different types of sensors, such as a bar or cloud of pressure sensors and / or forces and / or a beam or cloud of distance sensors of the laser type, with ultrasound, or for optical triangulation, optical analysis of the deformation of a projected network, projection of fringes, 3D analysis, or any other provision of sensors provided that carry out a sufficient number of measurements in order to scan, according to the desired azimuth, all the positions making it possible to have at least one effort measurement (three-dimensional) for each point (x, y, z; (x) of the cartography, the sensor cloud can in this case possibly be summarized to a single sensor, the latter case being particularly particularly conceivable when controlling the azimuth ac and the positioning (x, y, z) of the sensor relative to the tire sculpture as in the case of use on a rolling machine, or any sensor cloud that makes it possible to describe the entire width of the tire in an axis perpendicular to the direction of travel (the cloud sensors possibly being disjoint), this cloud of sensors possibly covering one or more subsets a basic pattern of the sculpture of the tire and, in the case where the matrix is summed up to a bar, the sensors could be positioned in a quinquonce so as to move the sensors transversely (dr) (or a substantially root ratio of 2) while recaling them temporally with a duration dt with dt = dx / vv being the speed of advance of the wheel

  along the x-axis (running axis) to obtain a better resolution.

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that it is positioned at least partly "above ground" in order to measure pressure maps or geometries in the space of an object during its passage and that, in the latter case, the sensor bar and / or

  The cloud of sensors can be three-dimensional.

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that it comprises a

  means of visualization of the object generating the ground effect.

  According to a particular embodiment, the invention relates to a device of the type described above, visualization means comprises cameras inserted in the test area, in particular the track, or on an upper or lateral gantry, under one or more prism (s) and / or porthole (s) transparent, the cameras realizing either an instantaneous visualization of the totality of the object, or a scan of the object, the latter advancing in the field of the cameras (linear cameras or cameras matrix or a conventional camera or a digital camera or diodes or matrices (including barrettes) of diodes) and that possibly the prism (s) and / or portholes and the camera (s) or diodes or matrix diodes are placed laterally on any inclination support or on a gantry placed above the zone

test or "area".

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that it is adapted to determine at a given moment the x, y position of the tire (or wheel, "object"). , "vehicle" etc ...) as well as its azimuth, and possibly to realize an image of the contact area to which

we are interested.

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that it comprises correction and correction means from a calibration performed upstream of the measurements and which implements a calibrated target which is applied to the upper surface of the prism, the contact areas of this target being preferably made of a flexible material (for example elastomer), and in that calibration may be carried out either upstream of the measurements or during the measurement phase or between measurements from features made on the upper face of the prism (for example the grooves used to increase the contact pressure or engraved crosses or even

  elements or inscriptions reported).

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that the tire rolls on a preferably transparent surface which may be for example a prism 45, in particular PlexiglasTM, or any material translucent or transparent and capable of withstanding the load or the effect created by the vehicle According to a particular embodiment, the invention relates to a device of the type described above, characterized in that it comprises at least one prism (or any transparent element, porthole, etc ... allowing an observation beyond the limit angle of the Nyquist law) (nl sin il = n2 sin i2 with i angles of incidence and n index of refraction) which is very flat, is inserted in the "floor" or in a rolling machine or in any other test means, and the observation camera associated with said prism is arranged in such a way that the viewing angle with respect to the surfa this of the prism on which rolls the

  pneumatic tire is sufficiently small to be smaller than the limit angle.

  According to a particular embodiment, the invention relates to a device of the type described above, characterized in that the visualization is carried out using at least one prism which has a shape which corresponds to the general case of a prism at 45, 50 o, etc ... or others

  shapes like a truncated prism or several prisms at 45, 50 etc ....

  placed one after the other, in order to reduce the thickness of the prism, and in that the angle alpha of the prism or prisms is 45 (angle measured between its upper face (face on which the tire rolls) and the observation face), or a higher angle, in particular angles of 45, 50, 70, 85 or 87 o or 89 under conditions called "total reflection" defined by the limit angle of the Nyquist law, in that it is possible to use several forms of prism in combination, for complementary analyzes, if necessary, and / or prisms placed according to any spatial arrangement, as will be obvious to the person skilled in the art, in that the visualization can also be carried out through a porthole (thus of angle 0) (in place of the prism or in combination with a prism) this process being particularly interesting in hydrodynamic environment (presence of a liquid type water + fluorescein on the track in the measuring zone), according to an observation direct viewing along an axis preferably perpendicular to the plane of the porthole, possibly with the presence of a colored liquid to substantially improve the distinction between the contact area and the areas not belonging to it, and in that the visualization can also combine prism (s) and porthole (s) for further analysis, if necessary, and / or portholes and prisms placed according to any spatial arrangement, and / or also use a "porthole" (angle = 0) or a prism to less than 45, that is to say 40, 30, etc ... if one wishes to carry out as a complementary option a direct aim "

  to see the entire tire.

  The invention also relates to the precise measurement method of contact area throughout the speed range, which consists of locating the contact area of the tire and its precise contour by optical measurement through a prism, by means of a camera operating in the visible or infrared or an infrared flash, the camera or the observation flash being arranged in such a way that the viewing angle with respect to the surface of the prism on which the tire rolls is sufficiently

  weak to be below the limit angle defined by the Nyquist law.

  An option according to the invention consists in carrying out a preliminary characterization (by 3D survey by distance laser sensors, feelers, etc., known) of the shape of the surface of the regrooved prism, which may be useful in the process to more precisely correct the raw image of its faults, distortions and aberrations made by the measurement method, but also to perform a calibration before the measurements ("blank" photo allowing such a calibration). The force measuring system or device consists of a matrix of force measuring sensors (generally

  three-dimensional) inserted into the ground.

  A conditioning and acquisition device.

  Specific treatment (the data from the force sensors are readjusted using the correction matrix previously established during

  device calibration) which will be described below.

  Combined with the measurement of efforts, and the image adjusted by the previous treatment, this treatment leads to a "global" treatment.

Description of the sensors

  The sensors used may for example be piezoelectric or gauged. Examples of collector cloud arrangement CF FIG 13 hereinafter V arrangement (Fig. 13A) It will be seen in this example (and in all other examples) that the sensors are not necessarily square, or that the squares

  are not necessarily identical.

  It is thus possible to combine square sensors of "large" (relatively) surface for an overall measurement, with small sensors.

  surface for a measurement in a specific area of the area.

  Head-to-tail arrangement (Fig. 13B) Spaced arrangement (Fig. 13C) Arrangement in any cloud (Fig. 13D) These various configurations are particularly interesting in order to have room for the imposing wiring. Indeed in the case of use of gauges, to obtain the best performance, it is advisable to use 6-wire gauges, and if one chooses to use for example a cloud of sensors of 100 three-dimensional sensors, the

  output wiring of the sensors then reaches 1800 wires.

  In a variant, it will be noted that any arrangement of sensors may be suitable, provided that a sufficient number of measurements are made in order to scan, according to the desired azimuth, all the positions making it possible to have at least one measurement of effort (three-dimensional ) for each point (x, y; cc) of the map. In this case, the sensor cloud can be summed up in a single sensor. This last case is particularly particularly conceivable when controlling the azimuth oa and the positioning (x, y) of the sensor with respect to the tire tread pattern as at

Rolling machine use.

  Example of a sensor array covering a complete longitudinal pattern (see FIG. 14) More generally, it will be noted that any sensor cloud that makes it possible to describe the entire width of the tire in an axis perpendicular to the direction of travel will be suitable (the sensors of the cloud

  may possibly be disjoint).

  If the cloud does not describe the entire width of the object, for example the tire, we will make several passes to sweep the whole

  width of the tire by the sensors.

  In a preferred embodiment, this cloud of sensors will cover in one or more subsets a basic pattern of the tire tread As will be seen below, to establish a mapping of the forces in the contact area of a tire strictly repetitive pattern (Figure 7), it is sufficient to have a matrix of minimum length (along the longitudinal axis of the tire) of the length of the pattern. Moreover, as we will see, this can be extrapolated to

  pneumatic tires with repetitive pattern but of variable length.

  In the case where the matrix is summed up in a bar, it would be wise to position the sensors staggered (see Figure 6) so as to move the sensors transversely (dr) (a substantially root ratio of 2) all by recaling them temporally of a duration dt with dt = dx / vv being the forward speed of the wheel along the x axis (driving axis). We obtain a better resolution. It is necessary, of course, to apply a rotation on the measurements made in x and

  y on the sensors to reposition themselves in the driving axis.

  It will also be noted that with a matrix of length less than the longitudinal length of the basic pattern of the sculpture of the tire, if the azimuth position is known during the measurement either by measuring the azimuth wheel or tire, or by knowledge of the part of the pattern having rolled on the bar as well as the x, y positioning of the tire (or the wheel, etc.) with respect to the matrix of sensors; then making successive passes until we have positioned parts of patterns to reconstruct a complete pattern then we have all the data to reconstruct a map

  complete contact area along any azimuth.

  Treatment applied to force measurements: The data from the force sensors are readjusted using the correction matrix previously established during the calibration of the device. The zeros of the sensors especially in the case of use of strain gage sensors are adjusted according to the calibration

  performed on site prior to the test sequence.

  Marking of measurements and additional information The image taken in the first step by the camera is assigned a spatial registration (Px, Py) which makes it possible to locate the image in the ground reference. This spatial location is at least better than (and may be equal to) the resolution sought in x, y and also that the

  precision sought on the azimuth of effort mapping.

  The image is also given an azimuth o (which makes it possible to know the azimuth of the tire (or wheel, etc.) corresponding to the shooting, This marking may in a variant make it possible to improve the performances of the device. be supplemented by a measurement of the angle of drift (pinching or deflection and evolution between the image-taking point and the point of effort measurement, which forces to recalibrate) of the wheel relative to the ground mark. can use measurements at the edge of the track (optical sensors), a comparison with the theoretical image, or a comparison with the grooves of the tire.This last measure is then used to rotate the photograph in rotation with respect to

  the drift measured on the wheel during the effort measurements.

  This registration can also be done by form recognition in the photographic image on the one hand (determination of the azimuth), and on the other hand by measurement on the vehicle (or object, etc ...) or measurement in " trackside ". in the latter case, we measure the positioning x, y (Px, Py) and possibly the orientation of the tire (or wheel, etc ...) simultaneously with the effort measurements and / or simultaneity

with the picture taking.

  The shape recognition will be based on the identification of a characteristic tire pattern, such as a "rib" (furrow) or a bread, and whose orientation will be known relative to the ground mark x, y It is also possible, according to a non-limiting variant, to use the orientation of the

  main axes of the contact area or its outline.

  We can furthermore complete the coordinates Px and Py by the orientation

  angle of the photograph with respect to the ground reference.

  The position of each of the centers of the sensors in the ground reference is measured beforehand, and each sensor i is thus assigned to

coordinates xi and yi.

  These measurements can then be used to finely adjust the measurements of the forces of each sensor with respect to the photograph and thus to the positioning and the azimuth of the tire (or the wheel, etc.). In a variant making it possible to improve the performances of the device, these coordinates can be supplemented by a measurement of the angular orientation of each sensor or of the whole of the sensor cloud with respect to the ground reference. This last measure is then

  profitably to rotate the force measurements in the ground reference.

  It is also possible to evaluate beforehand the altitude zi of each sensor with respect to the ground mark in order to make a correction on the measurements.

Fz of the sensor i.

  Each sample of effort measures is also assigned a

  time stamp and speed of advance of the wheel (or vehicle).

  For example, it is possible to measure using on-vehicle encoders mounted on the wheel axles, where the prior art is known.

  length of the developed wheel turn.

  As we know the coordinates of the photograph, but also the coordinates of the cloud of sensors in the ground mark, as well as the speed of advance of the wheel (or the vehicle), the length of the development of the wheel as well as the azimuth oa, we can then deduce the azimuth oci (t) corresponding to each sample of effort measurement. In order to simplify the implementation of the measurement method, the following tips can be used: If, for example, by instrumenting the wheel under test using an encoder (in particular an optical encoder), it triggers, for example, using telemetry between vehicle and track instrumentation or optical synchronization, measuring effort at the same azimuth x modulo wheel circumference as one of the effort measurement samples, if by recognition of shape (position of the patterns with respect to the contact area) the angle α (corresponding to the photograph is determined, it is possible by spatial registration and from the speed of advance of the wheel measured by this same encoder to affect an angle a (t) to each of

  force measurement samples from each of the sensors.

  This makes it possible to overcome (if we know the relative spatial distribution of the X-ray sensors) of the measurement Px and the location of the cloud of

sensors in the ground reference.

  If measurements are made in a straight line or cornering with a controlled trajectory (or if one measures the forces simultaneously with the shot (image)), or if the distance between the shot and the measurement of effort is small, we can use the approximation that is to say that the Y-registration coordinates between the image and the effort measurements of each sensor are known. For that it is necessary

  here also know the distribution in y of the sensors.

  Similarly, we can use the approximation which consists in saying that the evolution of the angle of drift of the wheel between the photograph and the measurements of forces of each sensor are known and thus bring about

  as before the appropriate correction.

  IR According to a particular and important embodiment, the invention relates to a device of the type described above, characterized in that

  place in front of the observation face an infra-red camera, or flash infra-

  red. The system or device in "contact" mode according to the invention consists essentially of:

  * A prism or other transparent element inserted into the ground.

From an observation camera.

  * A specific treatment; for example, if the starting image is a square, we recover a trapezoidal image, which should be straightened in the starting square, before eliminating any light biases and punctual defects as drops of water,

  dust etc ..., and finally before performing a "thresholding".

  Figure 3 shows the location and identification of the area of contact. The objective of this method is to determine at a given moment the

  position x, y of the tire (or the wheel etc ...) and its azimuth.

  Thus, by knowing, measuring or controlling the evolution of the azimuth and the positioning of the tire with respect to the force measurements, it will be possible to assign to the force measurements a positioning of the

pneumatic (rotation, registration).

  Another objective is to have an image of the contact area that we are interested in, even if we only use the image taking step (photography). In competition, it is thus possible to see if, and in what way, the tire is "placed on the ground" (visualization, measurement and characterization of the contact surface and its shape, which may range from a rectangle to a trapezium, a "diabolo", even a simple line in

extreme conditions).

  The treatment is divided into three phases: 1 Cleaning and straightening the image 2 Extraction of the contact area 3 Extraction of the coordinates of the contact area and the corresponding azimuth 1 Cleaning and straightening the image

  We will begin preferably by the recovery.

  Straightening The image received by the camera is deformed by perspective effect, since the observation is made along an axis that is not perpendicular to the object plane. On the other hand, the irregularities or inhomogeneities of the prism as well as the defects and errors related to the equipment and the shooting conditions lead to distortions.

  global, but also localized, which must be corrected.

  The recovery will be made from a calibration performed upstream of the measurements and which implements a calibrated test pattern that is applied to the upper surface of the prism. The contact areas of this pattern are preferably made of a flexible material (eg elastomer). In an interesting variant, the calibration will be carried out either upstream of the measurements, or during the measurement phase or between the measurements from features made on the upper face of the prism (for example the grooves used to increase the contact pressure or

  engraved crosses or added elements or inscriptions).

  The embodiments of these steps will not be unnecessarily detailed here because they are, once the principle and sequence defined, known to the skilled person, as for example any specialist

  working in the field of signal processing.

  Cleaning The image obtained generally includes various "pollutions" and noises

  related to dirt, parasitic lighting, etc ...

  The cleanup will consist of removing low spatial frequencies by

  filtering processes and straightening the contrast bias.

  Localized pollution may also be detected by

  the operator who will then make the correction he deems necessary.

  A complementary and particularly interesting technique is to take a shot without object placed on the prism and to make the corrections on this image then to apply them automatically to the following measures. We can also perform a subtraction of the image processing by the initial image made without object placed on the prism. 2 Extraction of the contact area The extraction of the contact area can be carried out automatically from the treatment described below or by manual selection of

  the operator or a combination of both.

  The treatment will be based on the difference in gray level between the contact area and the rest of the image (we can use a global threshold, or a scalable threshold plan, parabola or equivalent), but we can also use the local evolution of the contrast (we will use for example the Fourier transform in two dimensions of the image for

detect such transitions).

  3 Extraction of the coordinates of the contact area and the corresponding azimuth Coordinates of the contact area Initially, by calibration using a standard gauge identified in the track reference system, we are able to assign to each point of the image of

coordinates in this ground reference.

  The coordinates of the contact area in the ground reference will be evaluated preferably in two ways, the choice of which depends on the type of

tire sculpture.

  Barycentre of the contact area The coordinates of the contact area will correspond to the coordinates

  the center of gravity of the points constituting the area of contact.

  In a variant, it will be possible to use the center of gravity of the constituent points

  of the area of contact and weighted their gray level.

  Barycentre contour In this second solution, it will be described a contour (mathematical envelope of the contact area) and the coordinates of the contact area will be the coordinates of the center of gravity of the inner surface described by this contour. One possible variant is to determine several significant contours (for example bread contours) and to

  calculate the center of gravity of these outlines.

  Extraction of the azimuth It will start from a reference contact area which may consist for example of a first passage of the tire or a

  developed of the contact area of the tire.

  This reference contact area with the specific position of its rubber bars will then constitute the reference azimuth position to which the value O may for example be assigned. During the passages, and by shape recognition, the position of the one or more grounds of the area of contact and by comparison by

  relative to the reference, we will deduce the azimuth of the measured image.

  It is also possible, for example, from the basic pattern of the contact area to determine, by a method equivalent to that described above, the orientation of the contact area with respect to the track mark or to the initial image and to set take advantage of this information when reconstructing the area

  of contact by rotation of the corresponding effort measurements.

  1 o CAMERA The camera used can be a conventional camera or

a digital camera.

  The resolution of the photograph of the contact area is preferably at least half the resolution sought in x and y on the

contact area mapping.

  This photograph is carried out in gray scale or possibly in color (especially when used on the measurement zone of colored liquids with for example fluorescein, in order to study the viscoplaning and aquaplaning, it is recalled that the viscoplanage is the situation where the tire is still in contact with the ground but begins to float on a film of water, and that aquaplaning is the

  situation where the water film completely isolates the tread from the ground).

  The tire rolls on a preferably transparent surface which

  can be for example a prism to 45.

PRISM

  The prism (or any transparent element allowing an observation beyond the limit angle of the Nyquist law) (nl sin il = n2 sin i2 with i angles of incidence and n index of refraction), that is to say say in total reflection conditions, is of very great flatness, is inserted into the ground or into the rolling machine or in any other test means, and the observation camera is arranged in such a way that the angle of observation with respect to the surface of the prism on which rolls the

  pneumatic tire is sufficiently small to be smaller than the limit angle.

  Thus, according to this angle of observation, nothing is transmitted by the upper part of the prism except what has been emitted by the opposite face of the prism or by the portion of the tire in contact with the upper face. 9 various acceptable forms of prisms having an angle according to the invention are shown, these shapes not being

not limiting.

  Different forms of prisms: FIG. 9 represents non-limiting examples of particularly interesting forms of prism. The first form (FIG. 9A) corresponds to the general case of a prism at 45, 50 o, etc., the other two proposed forms (FIGS. 9B and 9C) are truncated prism shapes and several prisms at 45, 50 etc. ... placed one after the other, reduce the thickness of the prism, which facilitates the realization

  said prism and its integration into the soil.

  We can use several forms of prism in combination, for complementary analyzes, if necessary, and / or prisms placed according to any spatial arrangement, as will be obvious for humans

business.

PORTHOLE:

  The visualization can also be carried out through a porthole (in place of the prism), this process being particularly advantageous in a hydrodynamic environment (presence of a water-like liquid + fluorescein on the track in the measurement zone). An observation in direct view will be made here along an axis preferably perpendicular to the plane of the porthole. The presence of a colored liquid can further significantly improve the distinction between the contact area and

areas not belonging to it.

  We can also combine prism and porthole for additional analysis, if necessary, and / or portholes and prisms placed according to any spatial arrangement, as will be obvious for humans

business.

  Other features and advantages of the invention will be better

  understood in the following description, and with reference to the following

  attached drawing in which: - Figure 1 shows the block diagram of the general method according to the invention, applied to the mapping measurement of a contact area - Figure 2 schematically shows an implementation of a non-limiting variant of the invention for determining a contact area on a "rolling machine" - Figure 3 shows schematically the implementation of the invention for determining a contact area with a prism and camera system - the figure 4 schematically represents the implementation of the invention for the determination of a contact area at low speed - FIG. 5 schematically represents the implementation of the invention for determining a contact area at high speed - FIG. 6 represents a non-limiting mode of staggered positioning of the force measuring sensors. FIG. 7 represents a tire with strictly repetitive patterns, especially of the weight type. heavy - Figure 8, which consists of Figure 8A ("short" gum bread) and 8B ("long" gum bread) represents a repetitive longitudinal pattern but of variable length - Figure 9, which consists of the figures 9A, 9B and 9C, represents different forms of prisms that can be used according to the invention. FIG. 10 represents (prism section) a "regrooving" mode of the prism according to a non-limiting variant of the invention; FIG. 11 represents (top view of the prism) a mode of "regrooving" of the prism according to a variant not 12, which consists of FIGS. 12A, 12B, 12C and 12D, shows schematically the passage of the rubber loaf on the prism (FIG 12A) and the raw image "rectified" before reconstruction (FIG. Fig. 12B), thus (Fig. 12C) that the image obtained after the exclusion of

  recreated areas and (Fig. 12D) the reconstructed image by extrapolation.

  13, which consists of FIGS. 13A, 13B, 13C and 13D, shows an arrangement of the V-shaped sensors (FIG 13A), in "spade-head" (FIG 13B), in "spaced" bar (FIG. 13C) and in the cloud

any one (Fig. 13D).

  FIG. 14 represents a nonlimiting example of a sensor array according to the invention covering a "complete longitudinal pattern" of the tire. In the appended figures, the references have the same meanings, which are as follows: 1 prism 2 rolling road 3 upper face of the prism 4 opposite face of prism face of observation of the prism 6 angle upper face / face of observation 7 middle plane of the surface of the prism 8 actual surface (in section) of the surface of the prism 9 representation of the half wavelength used tread rubber of the tread 11 non-visible area 12 roll ("flywheel") 13 sensors of Efforts 14 Pneumatic Tested Encoders 16 Camera 17 Areas of "Regrooving" 18 Polished Surface (Object Plane) 19 Sensors (of all types depending on applications) Gum Bread "Short" Tread Gum Bread "Long" In the example shown in FIG. 3, the prism is in plexiglass, but any translucent or transparent material may be used.

  able to withstand the load of the vehicle.

  In the same example of FIG. 3, the "alpha" angle of the prism is 45 (angle measured between its upper face (face on which the tire rolls) and the observation face), but this angle is also nonlimiting, provided that one can observe in the conditions

specified above.

  The angle of 45 allows, if illuminated by the "opposite" face, to receive all the illumination except in areas where the tire is in contact with the upper face of the prism. In

  this last zone, the tire absorbs most of the light.

  It will be possible to use angles of 45, 50, 70, 85 or 87 or even 89 in so-called "total reflection" conditions, defined by

  The limit angle of Nyquist's law.

  It is also possible to use a "porthole" (angle = 0) and / or a 40-prism, etc. (or various combinations as suggested above), if it is desired to carry out a complementary option direct "to see the entire tire. If the window or the prism 30, 400, etc. are arranged in such a way, before or after the prism used in the conditions of "Nyquist", used according to the invention, that the offset of the measurement between the two processes (ie optical measurement (image acquisition) and force measurement) corresponds to exactly one revolution of the wheel, a correction is not necessary since the two measurements correspond to the same part of the tire If, on the other hand, there is an azimuthal offset, and if the azimuthal offset between the two measuring points is known (by known auxiliary means such as encoders, etc.), then a sufficient number of successive measurements until the two measurement methods are matched (for example, if the image is taken at an azimuth of 12 and the effort measurement is carried out at an azimuth of 48, make as many passes as necessary until the effort measurement is equal taken at

the azimuth 12 (or vice versa)).

  This method therefore produces a "negative" of the contact area. The optical paths of the different points of the image (Schempflug's law, which states that in order to obtain an undistorted image, one needs equivalent optical paths) impose to straighten the image.

distorted trapezium.

  In addition, to have an image of perfect sharpness, it is preferable that the image plane constituted by the surface of the prism, the plane of the lens of the camera and the plane of the image capture device.

  (negative, matrix CCD ...) are concurrent at one point.

  However, in the case of very weak capture devices

  dimension, this is not necessary.

  In the case of use in a hydrodynamic medium, that is to say a liquid spread over the test track, the angle of the prism must be adapted (68 o or more for a prism made of AltuglasTM material / water between its upper face and the observation face). It is the same between the face

upper and the opposite side.

  These devices make it possible to isolate any part of the tire positioned at a distance separating it from the surface of the lower prism

  or equal to 1/2 of the wavelength used.

  This is very discriminating, but when driving at high speed, the prism is not perfectly flat, the tire rolls on the points of the top of the prism (in particular by stiffening effect of the tires with the frequency) and some parts of the breads gum yet in contact with the prism are no longer identified as such. At high speed, for example pneumatic "slick" (smooth) at 80 km / h, most of the contact area disappears and only the areas where the localized pressure is very high (usually the edges

  bread and the edges of the sculpture).

  On a smooth tire or little sculpted, the image can completely disappear. This phenomenon is particularly troublesome on competition tires. Low speed: (see figure 4) In this diagram, the image in negative will describe all the gum bread. High speed: (see figure 5) At high speed, the bread is less indented in the micro roughness of the

  prism and, the image in negative will misrepresent some of the gum bread.

  To overcome this difficulty, it would naturally have a prism surface even smoother, but the technical possibilities and the cost of such achievements are unrealistic, nor the maintenance costs of the flatness of the prism (one uses a polishing machine, knowing that a single braking on the prism requires a polishing operation). According to an important variant of the invention, a particularly effective solution is according to the invention to be placed in front of the

  observation face an infrared camera, in direct or indirect mode.

  When the tire rolls on the prism, only the radiation emitted by a source positioned at less than half a wavelength

  of the actual surface of the prism will be able to be observed by the camera.

  If an infra-red camera is used (without infrared illumination by the opposite face of the prism), as the contact area of the tire heats up in rolling to reach a temperature different from (generally greater than) that of the ground, we will obtain an image of the area of contact. But the thermal radiation of the gum bread will also heat up (or cool if the area is very hot) the surface of the prism in contact or very close to the tire. This makes it possible to observe the entire surface of the contact area and to solve the phenomenon of attenuation and then disappearance of the high-speed image, which was very penalizing in the prior art ("erasing

the footprint "mentioned above).

  A variant according to the invention consists in using an infrared flash in the opposite part of the prism, so as to observe the contact area as a "cold zone of the prism". This last variant allows

  to be able to play between the advantages of the two processes.

  Finally, the observation using an infrared camera provides a lot of information on the operation of the tire and in particular the contact area for performing analyzes.

  warm-up, wear and effort.

  The invention also relates to a method and device known as "regrooving the prism" in viewing mode with a prism

  a camera, camera, etc .... as indicated above.

  This is a particularly important variant of the invention.

  Recreusage According to a particular embodiment, the invention relates to a device of the type described above, characterized in that an upper surface of the prism preferably perfectly smooth, but that will be recreated ("grid") so to reduce the upper surface in contact with the tire and thus increase the local pressure in order to increase the contrast of the image, this regrooving the surface leaving small individual surfaces not recreated and therefore preferably always perfectly smooth (polished) which will allow to observe the contact as before, these small surfaces (order of magnitude of the individual surface: from 10th of mm2 to a few square centimeters) being able to be dispersed in any cloud of points or arranged geometrically so as to constitute for example a matrix, with a rate of notching that can go up to 90% of the surface of the area, even 95% or even more (the limit e being a function of the tire, the speed, the surface of the prism, in particular). In another extremely important variant of the invention, a perfectly smooth upper surface is used as previously, but will be recreated ("grid") so as to reduce the upper surface in contact with the tire and thus increase the local pressure. to increase the contrast of the image. (see Figures 10, 11 and 12). At high speed, the tire is then

better on the observation areas.

  Currently, in Formula 1 for example, it is impossible to make measurements on prism at Formula 1 speeds, because no map is obtained, the tire pretending (or being deemed to) float "on the track, this which is naturally inaccurate The invention, in its variant "regrooving" in particular, brings for the first time

once a solution.

  The invention therefore also relates to the method of mapping contact area comprising the passage of a vehicle on a prism

"regrooved>".

  O This regrooving of the surface will leave small individual surfaces not regrooved and therefore always perfectly smooth (polished) which

  will allow to observe the contact as before.

  These small areas (order of magnitude of the individual surface: from mm2 to a few square centimeters) may be scattered in any scatter plot or geometrically arranged.

  way to constitute for example a matrix.

  The rate of notching thus created will be able to go up to 90% of the surface of the area, even 95% or even more (the limit being function of the

  pneumatic, velocity, surface of the prism, in particular).

  During the treatment, care should be taken to keep only the parts of

  the image corresponding to the unregistered areas.

  The image will no longer be a continuous image, but discrete. A particularly interesting treatment, particularly in the case of a geometric distribution of non-recreated surfaces, will be to artificially increase the area of the unregistered areas, up to

what these are joined.

  Recreusage of the prism to improve the contrast: see FIG 10, 11. 1 2 below) Cutting the prism (Figure 10) In this example, the contact surface between the prism and the tire is locally substantially divided by nine (square pattern) , the contact pressure is increased in a new ratio, the contrast of the shooting of the contact area is significantly improved. We will take care to regroove sufficiently the prism so that the tire does not come to rely significantly in the

regrooving area.

  We will also make sure to make a regrooving that respects the path

  optical rays from the object plane.

  Top view of the prism It is a question of FIG. 11, the hatched areas corresponding to the regrooving according to the invention, leaving polished surfaces

(white squares) of the object plane.

  Rectified raw image before reconstruction These are figures 12 A (real gumbread) and 12B (image obtained

with regrooving).

  Image after excluding recreated areas This is Figure 12 We will notice the level of contrast very pronounced.

  Image reconstructed by extrapolation This is Figure 12 D. Note the excellent correlation with the gum bread ", real"

departure.

  Reconstitution of the contact area We will distinguish two cases * Repetitive longitudinal patterned tires (in which we will include tires without a longitudinal pattern), or "smooth" tires (competition) * Repetitive longitudinal patterned tires of variable length If the tires are smooth or with a constant longitudinal pattern In the particular case of smooth tires or tires without a variation of pattern (for example, longitudinally grooved tires of Formula 1), it may be considered that all the azimuths are identical. to the azimuth desired for the mapping, and this makes it possible to dispose more quickly of all the data necessary for the establishment of this cartography, and thus to reduce the number of the passages (because the motives

are the same).

  Strictly repetitive longitudinal patterned tires On a pneumatic tire with a strictly repetitive pattern, such as for example in heavy weight: (FIG. 7) L Longitudinal length of the repeated pattern V direction of wheel advance It may be noted that, the three motifs P0, P1 , P2 being strictly identical, the forces generated by the pattern P1 at the instant t are identical to those generated by the pattern P0 at the instant t + DT and those generated by the pattern P2 at the instant t-DT with DT = L / V The contact area is considered not slipping on the ground, otherwise it would be advisable to replace V by the speed of the patterns with respect to the

center wheel.

  Thus, if one measures the mapping of the forces generated by a pattern throughout its crossing of the contact area and that a number of passages are made sufficient to have different azimuths (at the spatial resolution corresponding to v / f with f). frequency of acquisition), all the information is available to reconstruct a complete mapping of the contact area along any azimuth

  the spatial resolution corresponding to v / f with f acquisition frequency).

  Indeed, a contact area consists of a repetition of the motif of

  base, but view according to different azimuths.

  Thus the contact area will be reconstructed from the measurements made on an entire pattern as seen by the sensor array and corresponding to the azimuth oc to which the integer patterns corresponding to the azimuths a, + k * f will be joined with 3 corresponding to a length of pattern L view of the wheel center (L << R therefore 3 L / R with R crushed radius of the tire) and

k positive or negative integer.

  If the sensor cloud used does not describe the whole of a pattern, then it will suffice to make a larger number of passes for

  statistically arrive at an identical result.

  It will be noted here that the measurement azimuth of the tire (or of the wheel, etc.) and the positioning of the tire or the wheel, etc., in x, y (Px, Py) during the measurements of forces can be determined by optical edge measurement (a marker being fixed on the wheel or the tire, this mark can be reported or pre-existing as a valve), this measurement can also be performed using an on-board encoder

mounted on the vehicle wheel.

  Pneumatic tires with repeating longitudinal pattern but variable length Figure 8 Preliminary remark In the case of touring tires, it should be noted that the basic pattern is of variable length, but cyclical. Thus we can use the approach described in this chapter or the approach described in the previous chapter (repetitive patterns) by considering as a motif, no longer the basic pattern, but all of the basic patterns constituting a

  cycle of variation of length of this basic pattern.

* If we take into account that the forces generated in the contact area are related to the tread pattern only in the edges and edges of said patterns, then knowing the pitch variations of the patterns, as well as the azimuth of the measurement or by displaying the image of the surface of the contact area on which the measurement was made,

  can then completely reconstruct the area of contact.

  In fact, it suffices to extrapolate from a "long" bread to a "short" bread to use the same contour (this contour having for its width the width of the sensor of the matrix taken in the direction perpendicular to the advance of the vehicle and for length the length of the sensor of the matrix taken in the direction of advance of the vehicle), and to note that at the same spatial positioning Ca = Cc and Cb = Cd and that CO = C1 and CO = C2 at iso positioning (c 'ie to

identical positioning).

  In conclusion, by spatial and temporal repositioning from the knowledge of the development of the tread of the tire, it is possible to reconstitute a complete mapping of the area of the tire.

  next contact any azimuth.

  General or "global" treatment General reconstruction treatment is applied to the results

  from effort measurements (processed) and images (processed).

  We have seen that for each measurement of effort, we have assigned coordinates Px, PY, Pz an azimuth a and possibly an angle corresponding to the orientation of the measurement of effort relative to the track mark. When we have made enough passages to arrange for the desired angle (c) of at least one (three-dimensional) effort measurement for each x, y, z position of the map, then we have a composite algebraic system as many independent equations as unknowns, so we know we have enough information to reconstruct the mapping of

  (three-dimensional) along azimuth (a with the required resolution.

  The method then consists in applying a conventional reconstruction treatment that can be for example a determination of each point, starting from the edge of the contact area, and then evolving from close

  in the near until we have described the entire contact area.

  In some cases, it will be possible to stop the measurements before having described all the points of the contact area, for example if one is only interested in a part of the contact area for which one has

all the points.

  In case we stop while missing a small number of points to describe, we can try to reconstruct the contact area as described above but using conventional techniques

  interpolation to describe the missing points.

  We can for example use linear interpolations and apply the following approach: * If the missing point is inside a carving bread then we

  will interpolate the value of this point from its close neighbors.

  * If the point is on the edge of bread, then it will be interpolated only to

  from neighboring bread edge points.

  * If the point is located in a non-contact area (outer contact area, "rib", groove) then it will be assigned for each of its

stress components the value 0.

  Advantages of the invention in "CONTACT" mode: The measurement method of the contact area provides a great discrimination between the contact area and the areas of the ground that do not touch

not the tire.

  In addition, in the infrared variant, and especially in the case of the use of a regrooved prism, the device makes it possible to improve at high speed the contrast of the imprint, which tends to fade with

  conventional technologies (flash and measurement in the visible domain).

  The overall process of measurement of forces and visualization of the area: makes it possible to reduce the number of sensors of the matrix providing

  thus an economic gain and a gain on the reliability rate of the device.

  - allows to have a map in a reduced number of passages. The reconstruction processing also makes it possible to obtain a spatial resolution and a measurement accuracy which is clearly greater than that which is

obtained so far.

  This treatment makes it possible to obtain a true mapping according to a given azimuth and not a simple "averaging" of numerous measurements obtained according to random azimuths, this averaging only leading to an extremely approximate indication of the contact area, and

  not to a "real" mapping.

  The invention also relates to measuring and testing devices for the applications indicated here, and others obvious to those skilled in the art, characterized in that they comprise at least one

device as described herein.

  FIELD OF APPLICATION OF THE INVENTION, ALL MODES: The invention relates to all the applications of the processes and devices which have just been described, in particular to the following technical fields: Measurements by contact, or without contact, ("aerodynamic") or hydrodynamic ", that is to say by contact or without contact through a fluid, a gas or a liquid, on all the objects and vehicles set out above, in particular motor vehicles, motorcycles, bicycles, including competition, vans, trailers, caravans and heavy goods vehicles and heavy goods vehicles, competition vehicles, competition bikes, competition heavyweights, competition vehicles, aircraft, airplane wing, helicopter blade, wheel of any type , foot or shoe of a walker or runner or jumper in length or height in athletics, pole vault, swimmers or divers (sensor strips in the bottom of pool), tennis ball or balloon, ship, ship hulls, sailboats (sensor bars at the bottom of the pool and / or in the side wall of the pool and / or in any arrangement depending on the needs of the measurement), skiers and skiers, aerodynamic effect created by the passage of a fast object such as a train, an aircraft, a tennis ball, etc ...., and conversely the effect generated on the object during its penetration into a confined area such as a road tunnel, a railway tunnel, especially for fast trains "TGV", analysis of effects of a projectile either on the target or along its trajectory, precise measurement of a fingerprint, contact and detection of the presence of a liquid or fluid in a gaseous medium, or a

  gas in liquid medium etc .... and the like.

  This list, on the one hand is not exhaustive, and on the other hand will not be repeated: all these applications will be implicitly covered by the

  given examples, as already specified above.

  The invention also covers all the embodiments and all the applications that will be directly accessible to those skilled in the art.

  reading of this application, of his own knowledge.

Claims (37)

  1 Method for mapping - effects (including three-dimensional forces with or without a "contact") Fx, Fy, Fz - generated at each point i (xi, yi, zi) of an "area" < "on the ground", - by the passage of one or at least a part of an "object or vehicle", and in particular, in "contact" measurement mode, of an "object or vehicle "and in particular at least one tire, * and / or in particular at least one aerodynamic or hydrodynamic element of this" object or vehicle ", in" aerodynamic or hydrodynamic "measurement mode, characterized in that it comprises two steps: i measurements of effect parameters in the "area" "on the ground" by A At least one sensor matrix composed of effort sensors, identical or not, and mono-, di-, and / or three-dimensional , preferably three-dimensional, B optionally a characterization means of shape and / or location in the ground reference (that is to say relative to a reference of the test area or in particular the area), chosen from an image pickup and / or a set of sensors adapted to a shape and / or location characterization, in particular a set of distance measuring sensors, at the zone level or "area"> where the effects or forces are felt, allowing the location of a determined part of the "vehicle or object" with respect to a ground reference, reconstituting a mapping of the area of the forces (of effects on "ground," or possibly "ground" contact) by an appropriate means of treatment using or integrating or taking into account the relationship between the effect created (1A) and possibly the shape of the object or vehicle or part thereof having generated said effect (1 B).   Process according to Claim 1, characterized in that the sensor array consists of sensors or combinations of sensors.   in particular pressure sensors and / or effort.   3 Method according to claim 1 or 2 characterized in that the sensor array consists of at least one bar of pressure sensors and / or forces, such sensors being placed unsymmetrically or symmetrically, and / or at least one cloud of such sensors   or combination of such sensors, inserted in the "area".   4 Process according to any one of claims 1 to 3   characterized in that the sensors (in the form of a "bar", "cloud") can be fixed and the object or mobile vehicle, or the opposite (vehicle or fixed object and movable sensors relative to it in particular in the <"longitudinal direction>,) or in that the sensors and the object or vehicle are mobile in any way one compared to each other.   Process according to any one of claims 1 to 4   characterized in that the means (1 B) for determining the shape and / or location of the object or vehicle, or at least a part thereof, in the "ground" reference, are chosen from at least one camera inserted into the "ground" behind one or more portholes and / or prisms and / or other transparent devices, and / or inserted into the ground or out on the edge of the area among diodes or diode arrays, and or photogrammetric and / or stereoscopic means, and / or among distance measuring sensors, with or without contact (ultrasonic sensors, laser, optical triangulation, optical analysis of the deformation of a projected network, projection of fringes , 3D sensors), operating in visualization   snapshot of the entire object, or scan the object.   Process according to any one of claims 1 to 5   for obtaining a map of "area>" of forces or effects generated in the "ground" by the passage of an "object or vehicle" or at least a part thereof, without contact, aiming to assign to each coordinate point Px, Py, Pz ("positioning") of the force or effect or contact area, the forces Fx, Fy, Fz generated precisely at this point by the effect or effort, characterized in that: - at the level of an area of effects or efforts, composed of points of coordinates (Pxi, Pyi, Pzi), - we have a matrix of k means of measuring the forces (Fxi, Fyi, Fzi) generated at each point i by the passage on or in the vicinity of this area of an object or vehicle, or at least a part thereof, without contact, in particular a matrix k force sensors, preferably three-dimensional, measurements 1 - measurements are made (1A) by said means ci (by a passage of the vehicle or object on said and / or in the vicinity of said means ci) allowing a to give to the magnitudes (Fxi, Fyi and Fzi) (t) (measured directly by said means), on the one hand, effort measurements (measurements 1A) are carried out using a matrix of k force sensors preferably three-dimensional; * the effort measurements are made during the entire passage of the vehicle or object on or in the vicinity of said matrix, or for a period of at least (L + 1) / v with: L: Length of the area of ground effects I: Length of the sensor matrix v: vehicle advance speed or object * each sensor ci with (i <k) thus delivers at the acquisition time t all of the following data Fxi (t ), Fyi (t), Fzi (t) respectively corresponding to the forces measured at time t by the sensor ci along the longitudinal axis of the reference mark   (usually the ground or track mark), the transverse axis and the vertical axis.   * we then obtain a database of triplets of effort measurements of k columns and at least (L + I) * F / v lines with F acquisition frequency (the columns corresponding to the different sensors, the lines corresponding to different instants t of acquisition) * one carries out on the other hand (measurement 2 B) - using at least one means ML of location of the image-taking type, or edge of track or means of localization embedded on the vehicle (or a combination of these means) a spatial location in x, y, z of the area of effects and / or (depending on the means ML) of the object or vehicle at a time t which is the instant of said localization, t 'being (possibly) different from t because of the spatial shift (if any) between the sensor ci and the means ML of localization - one then deduces from it its coordinates (in reference reference ) that we will call Px (t ') Py (t') Pz (t ') - as we know Px (t'), Py (t ') and Pz (t') at time t 'and that we know the equation of the movement or the speed of advancement of the object or vehicle, substantially its direction, or its direction (angle / longitudinal axis), according to the means ML used, and the positioning of each sensor ci of the matrix d effort in the reference frame and the positioning of the locating means ML in this same frame; we are able to determine Pxi (t), Pyi (t), Pzi (t) corresponding to each of the triplets of forces Fxi (t), Fyi (t), Fzi (t) measured by the sensor ci at the instant t; a database of sextuplets of effort measurements, of k columns and (L + 1) / v lines is then constituted: (Fxi (t), Fyi (t), Fzi (t), Pxi (t), Pyi (t), Pzi (t)) the columns corresponding to the different sensors, and the lines corresponding to the different instants t of acquisition Reconstitution 2 of the effects area in "ground 1 - we want a real mapping of the forces or effects F corresponding to each point x, y, z of the area of effects at "ground" - so we extract from the previous database all sextuplets corresponding to this point that is to say such as x, y , z (j) (t) = x, y, z with (j <k) - one then positions each triplet of effort Fxi (t), Fyi (t), Fzi (t) at the point of coordinates Pxi (t) ), Pyi (t), Pzi (t) of the area, and - thus the mapping of the efforts generated at the level of   the area of "ground" effects at each point x, y, z of the area.   7 Process according to claim 6 characterized in that one carries out a measurement of forces by contact with the "ground" and one deduces, by subtraction of the forces measured on the ground, and of the static loads of the vehicle or object, the essential elements of the efforts   aerodynamic or hydrodynamic generated.   8- Process according to any one of claims 1 to 5   for obtaining a map of "<area" of contact generated at "ground" by the passage of an "object or vehicle" or at least part of it, with contact, intended to affect at each coordinate point Px, Py, Pz ("positioning",) of the contact area, the forces Fx, Fy, Fz generated precisely at this point by the contact, characterized in that - at an area of contact or effects or forces, composed of coordinate points (Pxi, Pyi, Pzi), - a matrix of k means for measuring the contact forces (Fxi, Fyi, Fzi) generated in each point i by the passage over this contact area of a tire or tread of an object or vehicle, or at least a part thereof, including a matrix of k force sensors, preferably three-dimensional measurements 1 - measurements (1A) are made by said means ci (by N successive passages of the vehicle or object on said means ci) to access the quantities (Fxi, Fyi and Fzi) (t) (measured directly by the said means) at the passage n (with n <N) are carried out on the one hand by force measurements (measurements 1A) using a matrix of k effort sensors ci preferably three-dimensional; * the effort measurements are made during all the contact between the matrix and the contact area of the tire, ie for a duration of at least (L + I) / v with: L: Length of the contact area I : Length of the sensor matrix v: speed of advance of the tire or the wheel or of any tread * each sensor ci with (i <k) thus delivers at the time of acquisition t the set of data Fxi (t), Fyi (t), Fzi (t) respectively corresponding to the forces measured at time t by the sensor ci along the longitudinal axis of the reference mark (generally the ground or track mark), the axis transversal and the vertical axis * we obtain then for the passage n a database of triplets of effort measurements of k columns and at least (L + 1) * F / v lines with F acquisition frequency (the columns corresponding to the different sensors, the lines corresponding to the different instants t of acquisition) * one carries out on the other hand (measure 2 B ) - using at least one ML means of location of the camera and prism type, or diodes or matrix of diodes, or average track edge or locating means on board the vehicle (or a combination of these means ) a spatial location and an azimuthal location of the contact area and / or wheel, tire, tread, according to the ML means employed, at a time t 'which is the instant of said location, t' being (possibly) different from t due to the spatial shift (if any) between the sensor ci and the ML means of localization - we then deduce its coordinates (in the reference frame) which will be called Px (t ') Py (t ') and Pz (t') as well as possibly its azimuth alpha (t ') - as we know Px (t'), Py (t '), Pz (t') and alpha (t ') at time t and the equation of the movement of the tire, wheel or tread, or the speed of advancement of the object or vehicle, substantially its direction, or its direction (angle longitudinal axis) specifies according to the means ML used, and the positioning of each sensor ci of the force matrix in the reference frame and the positioning of the locating means ML in this same frame; it is possible to determine Pxi (t), Pyi (t) and alpha i (t) corresponding to each of the triplets of forces Fxi (t), Fyi (t), Fzi (t) measured by the sensor i to moment t; Pxi (t) and Pyi (t) being the coordinates of the effort triplet in the mapping of contact area corresponding to the azimuth aci (t); then, for each passage n, a data base of seven tens of force measurements, k columns and (L + 1) / v lines: (Fxi (t), Fyi (t), Fzi (t), Pxi (t), Pyi (t), Pzi (t) and alpha i (t)) (n) the columns corresponding to the different sensors, and the lines corresponding to the different instants t of acquisition Reconstitution 2 of the contact area - we want a true mapping of the forces or effects F corresponding to a given azimuth alpha, the wheel, the tire or the tread on the contact area - we thus extract from the previous database constituted from the N passages every septuplets corresponding to this azimuth that is to say, such that alpha (j) (t) = alpha with (j <k) we then position each triple of effort Fxj (t), Fyj (t), Fzj (t) at the point of coordinates Pxj (t), Pyj (t), Pzj (t), and - we thus constitute the cartography of the three-dimensional forces   generated at the contact area along a chosen alpha azimuth.   9 Process according to claim 8 characterized in that the measurement of the azimuth alpha i is carried out at each passage: - by a photograph taken through at least one prism on which rolls the wheel or tire (or any band before or after its passage over the contact area where the measuring means are located, after which alpha i (at the area level) is deduced from the azimuth alpha p determined at the level of the prism, by a following methods: - if the distance between the measurement at the level of the area and the measurement at the level of the prism corresponds exactly to one turn of the wheel, no correction is necessary, the alpha p measured by the prism being hypothetically identical at alpha i measured at the area level; if said distance does not correspond to a wheel revolution, a correction is made by simple and known geometrical means, or by analysis of the data provided by a visual, magnetic or similar coder capable of measuring the alpha p at the level of the prism and the alpha i at the level of the measurement area, the prism thus giving the information Pxi, Pyi, Pzi at each passage, or else - by means of measurement at the edge of the track, such as 3D sensors, and / or on-vehicle means such as optical, magnetic coders giving a reference to the level of measurement area, the prism giving the information Pxi, Pyi, Pzi as above.   Process according to any one of claims 1 to 8,   characterized in that Pxi, Pyi and Pzi are directly determined by track edge measuring means by projecting a network of   fringes or photogrammetric and / or stereoscopic analysis.   Method according to one of Claims 8 to 10   characterized in that, in a hydrodynamic environment (presence of a liquid on the track in the measurement zone), a mapping of the pressures in the sculpture of the tire is made, and the flow velocities of the water are deduced therefrom. the channels of sculpture   (application of the Bernoulli formula P + pgz + 1 / 2pv2 = coast).   Process according to any one of claims 7 to 10   applied to the particular case of plain tires or tires with no longitudinal variation (eg longitudinally grooved tires of Formula 1), according to which it may be considered that all the azimuths are identical, characterized in that all the measurements correspond to the desired azimuth for cartography, which makes it possible to dispose more quickly of all the data necessary for the establishment of this cartography, and thus to reduce the number of passages to a small number typically three and even   possibly a passage (because the patterns are identical).   Process according to one of claims 7 to 10   applied to the specific case of tires with longitudinal patterns strictly repetitive, characterized in that the mapping of the forces generated by a pattern during its crossing of the contact area is measured and a sufficient number of passes is made to arrange the various azimuths, has all the information to reconstruct a complete mapping of contact area along any azimuth, and the contact area is reconstructed from the measurements made on an entire pattern seen by the sensor array and corresponding to the azimuth ca to which the integer patterns corresponding to the azimuths oa + k * f3 are contiguous with 13 angle corresponding to a length of pattern L seen from the wheel center (L << R therefore DL / R with R   crushed tire radius) and k positive or negative integer.   Process according to any one of claims 7 to 10   applied to the particular case of tires with repetitive patterns, characterized in that said repetition is used considering that a pattern is equivalent to the following modulo a length equal to the length of this pattern (or a time equal to the length of the pattern divided by the speed   progress of the wheel or the tire).   Process according to any one of claims 7 to 10   applied to the particular case of tires with a repeating longitudinal pattern but of variable length, characterized in that the pattern is no longer considered as the basic pattern, but all of the basic patterns constituting a cycle of variation of length of this pattern of basis, the forces generated in the contact area vary only strongly in the edges and edges of the tread patterns, the pitch variations of measure (or we have the image of the surface of the contact area on which the measurement was made, for example by a camera under prism) and we completely restore the contact area by moving from a bread "long" to a "short" bread, using for this the same contour (this contour having for width the width of the sensor of the matrix taken in the direction perpendicular to the advance of the vehicle and for length the length of the sensor of the taken matrix e in the direction of travel of the vehicle), and integrating the fact that at the same spatial positioning Ca = Cc and Cb = Cd and that CO = C1 andCO = C2   at iso-positioning (that is, at identical positioning).   that is to say, we can reconstruct a complete mapping of contact area according to any azimuth by spatial and then temporal repositioning from the knowledge of the development of the tread of the tire and the complete measurement of a basic pattern.   Process according to one of Claims 1 to 15,   characterized in that the treatment is divided into three phases: 1 Cleaning and straightening of the image 2 Extraction of the contact area 3 Extraction of the coordinates of the contact area and the corresponding azimuth in that the straightening takes place made from a calibration performed upstream of the measurements and which implements a calibrated pattern which is applied to the upper surface of the prism, the contact areas of this pattern being preferably made of a flexible material (for example elastomer) in that the calibration is carried out either upstream of the measurements or during the measurement phase or between measurements from features made on the upper face of the prism (for example the grooves used to increase the contact pressure or engraved crosses) or elements or inscriptions reported) in that the extraction of the contact area is performed automatically or manually and in that the extracti coordinates of the contact area by initial calibration using a standard test pattern located in the track reference, which allows to assign to each point of the image coordinates in this ground reference; then we evaluate the coordinates of   the contact area in the ground reference.   Process according to any one of claims 7 to 16   characterized in that a shooting is carried out without object or vehicle placed on the prism and corrections are made on this image and then automatically applied to the following measurements, possibly subtracting the image in treatment by   the initial image made without object placed on the prism.   Process according to any one of claims 7 to 17   characterized in that the measurements (1A) are completed by measurements of longitudinal, transverse and vertical forces carried out on each   wheels from measuring blocks inserted into the ground.   Process according to any one of claims 7 to 18   characterized in that only one image of the contact area to which one is interested is made, through a prism operating in   total reflection, that is, whose angle alpha is> = 45.   Process according to any one of claims 11 to 23   characterized in that the tire is passed over a "regrooved" prism, that is to say on an upper surface of the prism preferably perfectly smooth, but that will be recreated ("<grid") so as to reduce the surface superior in contact with the tire and thus increase the local pressure to increase the contrast of the image, this regrooving the surface leaving small individual surfaces not regrooved and therefore always perfectly smooth (polished) that will observe the contact as before, these small surfaces (order of magnitude of the individual surface: from 10th of mm2 to a few square centimeters) which can be dispersed in any cloud of points or arranged geometrically so as to constitute for example a matrix, with a rate of notching which can go up to 90% of the surface of the area, even 95% or even more (the limit being a function of the tire, the speed, the surface of the prism, in particular). 21 Apparatus for mapping - effects (including three-dimensional forces with or without a "contact") Fx, Fy, Fz generated at each point of an "area" "on the ground" - by the passage of one or two at least part of an "object or vehicle", and in particular, in "contact" measurement mode, at least one "object or vehicle", for example a tire, and / or in particular at least one aerodynamic or hydrodynamic element of this "object or vehicle", in "aerodynamic or hydrodynamic" measurement mode, characterized in that it comprises A at least one sensor array, of length generally less than the area of effects on the ground or contact, in the longitudinal direction (ie passage) or not, and composed of effort sensors, identical or not, and mono-, di-, and / or three-dimensional, preferably three-dimensional , B optionally a means of characterization of shape and location in the ground reference (that is to say, rap port to a reference of the test area or in particular of the area), selected from an image pickup or a set of sensors adapted to a shape characterization, in particular a set of distance measuring sensors, at the level of of the zone or "area" where the effects or efforts are felt, allowing the localization of a part   determined "vehicle or object" with respect to a ground reference.   22 Apparatus according to claim 21 characterized in that it comprises a suitable means of processing adapted to the reconstruction of an area mapping efforts (effects "ground" or possibly contact "ground") using or integrating or taking into account the relation between the effect created (1 A) and possibly the form   of the object or vehicle or part thereof having generated said effect (1 B).   Device according to claim 21 or 22, characterized in that the sensor array consists of sensors or combinations of   sensors, especially pressure and / or effort sensors.   Apparatus according to any one of claims 21 to 23,   characterized in that the sensor array consists of at least one array of pressure sensors eVt / or forces, such sensors being unsymmetrically or symmetrically placed, and / or at least one such cloud. sensors or combination of such sensors,   O10 inserted in the "area".   Device according to one of Claims 21 to 24,   characterized in that the sensors (in the form of a "bar", "cloud") can be fixedly mounted while the object or vehicle is mobile, or the opposite (vehicle or fixed object and movable sensors with respect to especially in the "longitudinal direction") or in that the sensors and the object or vehicle are   any relative to each other.   Device according to any one of claims 21 to 25   characterized in that the shape determining means (1 B) and / or   location of the object or vehicle, or at least a part thereof.   ci ,, in the "ground" mark, are chosen from at least one camera inserted into the "ground" behind one or more portholes and / or prisms and / or other transparent devices, and / or from distance measuring sensors. , with or without contact (ultrasonic sensors, laser, optical triangulation, optical analysis of the deformation of a projected network, 3D sensors, photogrammetric and / or stereoscopic analysis), operating in instantaneous visualization of the entire object , or in scanning of the object and / or means embarked on the vehicle   as optical, magnetic and analog encoders.   Apparatus according to any one of claims 21 to 26 for   Obtaining an "area" map of efforts or effects generated in the "ground" by the passage of an "object or vehicle" or at least a part thereof, without contact, aiming at assigning to each coordinate point Px, Py, Pz ("positioning") of the force or effect or contact area, the forces Fx, Fy, Fz generated precisely at this point by the contact, The effect or the effort, characterized in that: - at the level of an area of contact or effects or efforts, composed of points of coordinates (Pxi, Pyi, Pzi), - the means of measuring the forces (Fxi, Fyi, Fzi) generated at point i by passing on or near this area of an object or vehicle, or at least a part thereof, without contact, 28 Device according to claim 27, characterized in that   has more means for measuring forces by contact "ground".   Apparatus according to any one of claims 21 to 26 for   obtaining a mapping of "area" of forces or effects generated in the "ground" by the passage of an "object or vehicle", with contact, intended to assign to each point of coordinates Px, Py, Pz ("positioning") of the contact area, the forces Fx, Fy, Fz generated precisely at this point by the contact, the effect or the effort, characterized in that: - at the level of an area of contact or effects or efforts, composed of coordinate points Pxi, Pyi, Pzi - means are available to measure the forces generated by the passage on this area of an object or vehicle, such as a wheel, a tire, as well as means for measuring the azimuth alpha i at each passage: by a photograph taken through at least one prism on which the wheel or the tire (or any strip of rolling) rolls before or after passing over the contact area where the measuring means are located, after which we deduce alpha i (at the area level) from the alpha azimuth p determined at the level of the prism, by one of the following methods: - if the distance between the measurement at the level of the area and the measurement at the level of the prism corresponds exactly to one turn of the wheel, no correction is necessary, the alpha p measured with the prism being hypothesized to be identical to the alpha i measured at the level of the area; if said distance does not correspond to a wheel revolution, a correction is made by simple and known geometrical means, or by the analysis of the data provided by a visual, magnetic or similar coder capable of measuring the alpha p at the level of the prism and the alpha i at the measurement area, the prism thus giving   information Pxi, Pyi, Pzi at each pass.   or - by means of "runway edge" measuring means such as 3D sensors, optical, magnetic and similar coders, embarked on the vehicle, giving a reference to the level of the   measure, the prism giving the information Pxi, Pyi, Pzi as above.   Device according to any one of claims 21 to 29,   characterized in that track edge measuring means are provided, for example by projection of a fringe array, capable of directly determining Pxi, Pyi and Pzi.   Apparatus according to any one of claims 21 to 30   characterized in that the positioning of the sensors is generally not longitudinal, and in particular in that the positioning is substantially perpendicular to the axis of the object or the vehicle.   Apparatus according to any one of claims 21 to 31   characterized in that the sensors that make up the bar or strips are spaced a distance of between a few hundredths of a millimeter and a few centimeters and are positioned preferably aligned, staggered or V, head-to-tail, are flush with respect to the top of the bar, but may be indented or slightly exceed.   Apparatus according to any of claims 21 to 32   characterized in that the device comprises at least one sensor cloud, several clouds, several bars, or combinations of these formulas.   Apparatus according to any of claims 25 to 33   characterized in that it is positioned at least partly "above ground"> to measure pressure maps or geometries in the space of an object during its passage and in that, in the latter case, the Sensor array and / or sensors can be three-dimensional.   Device according to any one of claims 21 to 34   characterized in that it comprises means for visualizing the object generating the ground effect.   36 Apparatus according to claim 35 characterized in that said display means comprises cameras inserted in the test zone, in particular the track, or on an upper or lateral gantry, under one or more prism (s) and / or porthole ( s) transparent, the cameras realizing either an instantaneous visualization of the totality of the object, or a scan of the object, this one advancing in the field of the cameras (linear cameras or raster cameras or a conventional camera or a camera digital or diodes or   dies (especially bars) of diodes).   37 Device for performing contact area mapping of a   pneumatic system according to one of claims 21 to 36   characterized in that it combines different types of sensors, such as a bar or cloud of pressure and / or force sensors and / or a bar or cloud of laser-type distance sensors, with ultrasonics, or for triangulation optical, optical analysis of the deformation of a projected network, projection of fringes, 3D analysis, or any other arrangement of sensors, provided that a sufficient number of measurements are taken in order to scan, according to the desired azimuth, all the positions making available at least one effort measurement (three-dimensional) for each point (x, y, z; o) of the map, the cloud of sensors being able in this case to be summed up possibly in a single sensor, the latter case being particularly particularly possible when controlling the azimuth c (x and the positioning (x, y, z) of the sensor relative to the sculpture of the tire as when used on a rolling machine, or any cloud sensor to describe t the width of the tire in an axis perpendicular to the rolling direction (the cloud sensors possibly being disjoint),   this cloud of sensors possibly covering in one or more sub-   sets a basic pattern of the sculpture of the tire and, in the case where the matrix is summed up to a bar, the sensors could be positioned in a quinquonce so as to be able to move the sensors transversely (dr) (ie a substantially root ratio of 2) while recaling them temporally with a duration dt with dt = dx / vv being the forward speed of the wheel along the x axis (running axis)   in order to obtain a better resolution.   38 Apparatus according to claim 37 characterized in that it is adapted to determine at a given moment the position x, y and possibly z of the tire (or wheel, "object", "vehicle" etc ...) and its azimuth, and possibly for   create an image of the area of contact to which one is interested.   39 Device according to claim 37 or 38 characterized in that it comprises correction and correction means from a calibration performed upstream of the measurements and which implements a calibrated pattern which is applied to the upper surface of the prism , and we   implements features of the upper face of the prism.   Device according to any one of claims 37 to 39   characterized in that the tire rolls on a preferably transparent surface which may be for example a 45-prism, especially PlexiglasTM, or any translucent or transparent material capable of withstanding the load or effect created by the vehicle   Apparatus according to any one of claims 37 to 40   characterized in that it comprises at least one prism (or transparent element, in particular a porthole, allowing an observation beyond the limit angle of the Nyquist law) (nl sin il = n2 sin i2 with i angles of incidence and a refractive index) which is of very great flatness is inserted into the "ground" or into a rolling machine, and the observation camera associated with said prism is arranged in such a way that the angle of observation with respect to the surface of the prism on which the tire rolls is sufficiently small to be smaller than the limit angle.   Apparatus according to any one of claims 37 to 41   characterized in that the visualization is carried out using at least one prism which has a shape which corresponds to the general case of a prism at 45, 50 o, etc ... or other forms such as a prism truncated or several prisms at 45, 50 etc .... placed one after the other, to reduce the thickness of the prism, and in that the angle alpha of the prism or prisms is 45 "(measured angle between its upper face (face on which the tire rolls) and the observation face), or an upper angle, in particular angles of 45, 50, 70, 85 or 87 or 89 under conditions referred to as "total reflection" conditions. defined by the limit angle of the Nyquist law, in that the visualization can also be carried out through a porthole (thus of angle 0) (in place of the prism or in combination with a prism), in particular in a hydrodynamic environment (presence of a water-like liquid + fluorescein on the runway in the measurement zone), according to an observation in v direct alignment along an axis perpendicular or not to the plane of the window, possibly with the presence of a colored liquid to substantially improve the distinction between the contact area and the areas not belonging to it, and in that the visualization can also combine prism (s) and portholes (s) for complementary analyzes.   Apparatus according to any one of claims 37 to 42   characterized in that a camera is placed in front of the observation face infra red.   44 Apparatus according to any one of claims 37 to 43   characterized in that an upper surface of the prism is preferably perfectly smooth, but will be recreated ("grid") so as to reduce the upper surface in contact with the tire and thus increase the local pressure to increase the contrast of the image, this regrooving of the surface leaving small individual surfaces not recreated and therefore preferably always perfectly smooth (polished) which will make it possible to observe the contact as lo previously, these small surfaces (order of magnitude of the surface individual: from 10 "mm 2 to a few square centimeters) can be dispersed in any scatter plot or geometrically arranged so as to constitute for example a matrix, with a notch rate that can go up to 90% of the surface the area, even 95% or even more (the limit being a function of the tire,   velocity, the surface of the prism, in particular).   Application of the method according to Claim 1 or the device according to Claim 21 to measurements of area, by contact, or without contact ("aerodynamic" or "hydrodynamic"), that is to say by contact or without contact through a fluid, a gas or a liquid, on an "object" or vehicle >>.   46 Application of the device according to any one of   Claims 37 to 43 to the measurement of contact area of a tire.   47 Application according to claim 46 on a test device of   tire called "rolling machine". 101 2812085   48 Application according to claim 45 to: - motor vehicles, motorcycles, bicycles, especially competition, vans, trailers, caravans and heavy trucks and heavy goods trailers, competition vehicles, competition bikes, competition heavyweights, competition vehicles, aircraft, airplane wing, helicopter blade, wheel of any type including rail (TGV), foot of a walker or runner, fingerprint, ship, hull of ships, sailboats, ski and skiers, aerodynamic effect created by the passage of a fast object such as a train, an aircraft, contact and detection of the presence of a liquid or fluid in a gaseous medium, or a gas in a liquid medium, etc., and conversely the effect generated on the object when entering a confined area such as a road tunnel, a railway tunnel, and the like.