EP0692421A1 - Control method for steering of running gears with orientable wheels of a set rolling on rail and set using this method - Google Patents

Abstract

The railway vehicle has wheel boxes (2-4) articulated to each other, and wheels (8 -11) whose direction can be adjusted to obtain tangency with the rails. Detectors (40) are used to measure the relative angles between the longitudinal axes (31) of the wheel boxes. For each wheel assembly, the variable angle ( alpha 1, alpha 2, alpha 3, alpha 4) between a direction perpendicular to the wheels' axes (37) and the longitudinal axis of the concerned wheel box is determined. These are determined from the measured relative angles and preferably in combination with the angular rotation speed of the wheel boxes about their vertical axis measured by gyroscopic detectors on the boxes. An actuator adjusts the wheel direction as a function of the calculated angles. <IMAGE>

Description

The present invention relates to a method for adjusting the orientation of rolling devices with steerable wheels of a rolling assembly on rails comprising at least two rolling units, wagons or boxes making up a wagon, articulated and / or coupled one to the other. 'other, the assembly being arranged on the rails by means of rolling devices with steerable wheels whose main planes make variable angles with a direction parallel to the longitudinal axis of the rolling unit on which they are mounted, the method being carried out by adjusting said variable angles as a function of the curvature of the rails so that the main planes of the wheels are substantially coincident with tangents to the rails.

In such rolling assemblies, in particular trams, it is for certain applications very important to lower the floor of the vehicle as much as possible. It is no longer possible to use bogies with two or more axles. It is then preferable to use rolling devices comprising only two wheels which must be guided adequately.

Such an articulated railway vehicle is known in which the rolling devices are guided so mechanical thanks to a guide pulley cooperating with a side rail. This device requires the installation of an additional guide rail and therefore cannot be applied to all possible urban uses. In addition, the device is very expensive.

The object of the present invention is to remedy these drawbacks and the invention is characterized in that the relative angle between the longitudinal axes of at least two rolling units is measured, in that the said said are calculated variable angles for at least one of the rolling devices as a function of said measured relative angle and that its wheels are oriented in accordance with said calculated variable angles.

By these measures, an articulated railway vehicle is obtained in which the wheels are at all times in tangency with the rails. Derailment safety is increased. The characteristic squeaking noise of curved trams is greatly reduced, if not eliminated, and wheel wear is significantly reduced. The process is also easily carried out and of a relatively low cost price. Due to the orientation of the wheels given by the calculation and not by a mechanical control, the adjustment of the wheels can be adapted to all routes and can be modified and improved later at very little cost.

An advantageous variant is characterized by the fact that the position of the rolling devices is identified according to a coordinate system, that an arc of circle function of at least one osculating circle passing through the centers of three is determined. rolling devices and that the value of said variable angles is determined from the derivative of said arc function.

Since the railways consist of straight lines and arcs of circles, these arrangements make it very easy to obtain an excellent orientation of the wheels.

Advantageously, the variable angles obtained by the osculator circle (s) are corrected by means of empirical correction functions based on the variation of said relative angles for a distance traveled.

It is thus possible to correct irregularities in the course such as entering and exiting curves or "S" curves.

The method can be adapted to rolling assemblies comprising at least three rolling units and at least four rolling devices. It is then characterized by the fact that a first relative angle is measured between a first and a second rolling unit and a second relative angle between the second and a third rolling unit, by the fact that at least these two are used relative angles for determining at least two functions of arcs of a circle of at least two osculating circles, a first passing through the centers of the first three rolling devices, the second passing through the centers of the last three rolling devices, and through the fact that the value of said variable angles is determined from the derivatives of the two arc-of-a-circle functions, the value of the variable angles of the rolling devices belonging to two osculating circles being obtained by averaging the values obtained by each of the osculating circles.

The method can also be adapted to rolling assemblies comprising a number of rolling units greater than three, it is then characterized by the fact that several osculating circles are determined by group of three rolling devices, all the rolling devices having with the exception of those arranged at the end of the rolling assembly, used for the interpolation of two osculating circles and the relative angles being obtained by average of the values obtained by each of the two osculating circles, the variable angles obtained being corrected with by means of said correction functions.

By these methods, a very precise orientation of the wheels is obtained using inexpensive means which can be adapted at any time.

The invention also relates to a rolling assembly on rail, the orientation of the wheels of which is adjusted according to the previously defined method, comprising at least two rolling units, wagons or boxes making up a wagon, articulated and / or coupled one to the other. other, the assembly being arranged on the rails by means of rolling devices with steerable wheels whose main plane forms a variable angle with a direction parallel to the longitudinal axis of the rolling unit on which they are mounted, characterized by the fact that the rolling assembly comprises at least one adjustment device intended to adjust said variable angle as a function of the curvature of the rails so that the main plane of the wheels is substantially coincident with the tangent to the rails, this device adjustment comprising at least one measuring member capable of determining a relative angle between the longitudinal axes of at least two rolling units, at least one calculation unit intended to calculate the variable angles for each of the rolling devices as a function of said relative angle , and adjustment members associated with the rolling devices and capable of orienting the wheels in accordance with said calculated variable angle.

The rail vehicle therefore has according to the invention means that are simple to assemble and inexpensive, making it possible to obtain precise orientation of the wheels, thus ensuring increased safety.

Other advantages emerge from the characteristics expressed in the dependent claims and from the description setting out the invention below in more detail with the aid of drawings which schematically represent by way of example two embodiments and variants.

Figure 1 is a schematic perspective view of a first embodiment in the form of a tram, the upper part of the vehicle being separated from the chassis for clarity.

FIG. 2 shows in perspective a rolling device used in the vehicle illustrated in FIG. 1.

Figure 3 is a schematic plan view of the vehicle of Figure 1.

FIG. 4 represents a block diagram of the adjustment device used in the vehicle illustrated in FIG. 1.

Figure 5 is a schematic plan view of a variant showing a different arrangement of the devices of rolling.

Figure 6 is a schematic plan view of a second embodiment.

The rolling assembly represented in FIG. 1 is a tram 1 comprising three rolling units in the form of boxes 2, 3 and 4 articulated to each other in a mobile manner by means of bellows joints 5. Each box is composed of a chassis 6 and a superstructure 7. The first box 2 comprises two rolling devices 8, 9 each with two steerable wheels, while the second and third boxes 3, 4 each comprise only a rolling device 10, 11. Such a rolling device, or bogie with two wheels, is illustrated in more detail in Figure 2. It has two wheels 15, 16 driven separately by motors 17, 18 whose frame is fixed to a frame 20 of the device rolling . The chassis 20 has two cross members 21 connected by spacers 22 and stabilizer bars 23. It also supports electromagnetic brakes 24 intended to cooperate with the rails 25. A ring 28 secured to the chassis 20 via the bars 23, serves as a connecting pivot with the body 2, 3 or 4 on which the rolling device is rotatably mounted.

The rolling assembly further comprises, associated with each rolling device 8 to 11, an adjustment device 30 intended to adjust a variable angle (αj) between the main plane 32 of the wheels 15, 16 and a direction parallel to the axis. longitudinal 31 of the body 2, 3, 4 on which the rolling device is mounted. This adjustment device thus makes it possible to adjust the orientation of the wheels according to the curvature of the rails so that the plane of the wheels 32 is substantially coincident with the tangent to the rails. The adjustment device comprises for this purpose an adjustment member in the form of a controlled jack 34 connecting the chassis 20 of the rolling device to the chassis 6 of the boxes 2, 3, or 4.

FIG. 3 schematically illustrates the boxes 2, 3 and 4, the rolling devices 8 to 11 being oriented in such a way that the planes of the wheels or the normals 36 to the axes 37 of the wheels make variable angles α1, α2, α3 or α4 with the longitudinal axes 31 of each box 2, 3,4. The relative angles β1, respectively β2 between the longitudinal axes 31 of the first 2 and of the second 3 box, respectively between the longitudinal axes 31 of the second 3 and of the third 4 box are used for the calculation of the variable angles α1, α2 , α3 and α4. For this purpose, the tram includes a measuring member 40 associated with each articulation between two boxes in the form of a sensor intended to measure the relative angle β1 or β2. These sensors 40 are placed under the hinge ring. Part of the sensor is secured to the crown while another part is secured to the body. An inductive or capacitive measurement system makes it possible, by the field variation recorded between the two elements making up the sensor, to know the rotation of the crown. The values of the variable angles β1, β2 measured are delivered to a calculating unit 41 which calculates the values for each of the angles αj of each of the rolling devices. The angle values αj are routed to servo controllers 42 (fig. 2) intended to control the movement jacks 34 associated with each of the rolling devices for orienting the wheels in accordance with said variable angles αj calculated so that the main planes of the wheels are substantially coincident with the tangents to the rails.

The calculation unit 41 is arranged so as to develop an equation for the trajectory of the rails, which then provides, at all points, the tangent to the trajectory, which allows ideal positioning of the wheels of the rolling devices thus minimizing their friction with the rails.

The choice of the functions for the equation of the railway layout is relatively simple since the layouts generally consist either of straight lines or of arcs of a circle. The functions used will therefore be lines and osculating circles for which it remains to calculate the parameters, namely the coordinates of their centers a, b and their radii ρ.

Take the example of a train consisting of three boxes (fig. 3). A coordinate system is attached to the first box. The center of the first three rolling devices or bogies is located in relation to this system; they define the first osculating circle. In the same way, the center of the last three rolling devices or bogies are identified and define the second osculating circle.

The derivatives of the osculating circles at the positions corresponding to the centers of the rolling devices give the direction of tangency of the wheels. In the case where a rolling device belongs to the two osculating circles, there are two tangents. The final result is obtained by taking the average between the two tangents.

If the tram is located on a straight line or in a curve with a constant radius, the mathematical approximation will be exact. In all other cases (curve entry, curve with variable radius, etc.) an error will appear. This error could, if necessary, be reduced by the introduction of correction functions, based on the variation of the angles Δβ between the boxes for a distance traveled.

a, b [m]

coordonnées des centres des cercles osculateurs

e [m]

entr'axe entre les dispositifs de roulement

l,la [m]

longueurs entre dispositifs de roulement et articulations

m

pente des tangentes aux cercles osculateurs

s [m]

distance parcourue

t [sec]

temps

v [m/sec]

vitesse

x,y [m]

coordonnées des centres des dispositifs de roulement

G,H,K,L [m]

facteurs de correction dépendant de la géométrie de l'unité roulante et du dispositif de roulement concerné

α [degrés]

angle variable par rapport à l'axe de la caisse

αC [degrés]

angle variable corrigé par rapport à l'axe de la caisse

β [degrés]

angle relatif entre les caisses

γ [degrés/m]

constante correspondant à une limite d'un intervalle de mesure.

ρ [m]

rayon des cercles osculateurs

ψ [degrés]

angle des tangentes au premier cercle osculateur

ψ' [degrés]

angle des tangentes au deuxième cercle osculateur

χ

matrice

   Les coordonnées des centres des dispositifs de roulement sont données par les secteurs suivants :

   On cherche un cercle de rayon ρ et de centre (a,b) passant par un groupe de trois points correspondant aux centres des dispositifs de roulement. L'équation du cercle est du type : $$\text{(}\mathit{\text{x}}\text{-}\mathit{\text{a}}{\text{)}}^{\text{2}}\text{+ (}\mathit{\text{y}}\text{-}\mathit{\text{b}}{\text{)}}^{\text{2}}{\text{= <figure-callout id="2" label="ρ" filenames="imgf0001.png" state="{{state}}">ρ</figure-callout>}}^{\text{2}}$$

qui peut s'écrire sous la forme d'une fonction d'arc de cercle : $$\mathit{\text{y}}\text{=√}\overline{{\text{ρ}}^{\text{2}}\text{-(}\mathit{\text{x}}\text{-}\mathit{\text{a}}{\text{)}}^{\text{2}}}\text{+}\mathit{\text{b}}$$

La dérivée $\text{m = y'(x)}$

de 1.6 est donnée par l'équation :

La valeur de cette dérivée au point x donne la pente de la droite tangente à l'arc de cercle, au point considéré. Son angle avec l'abcisse est $$\text{ψ = arctg(m)}$$

   Le calcul des coordonnées du centre et du rayon ρ des cercles osculateurs revient à la résolution d'un système à trois équations 1.5 à trois inconnues (a, b et ρ) et qui peut s'écrire, pour le premier cercle osculateur, sous la forme matricielle suivante :

et pour le deuxième cercle :

Les rayons ρ1 et ρ2 des cercles osculateurs sont calculés à l'aide de l'équation 1.5.
La détermination des centres (a1,b1), (a2,b2) et des rayons ρ1 et ρ2 des deux cercles permet le calcul de tous les angles ψ grâce aux équations (1.7) et (1.8).The following symbols will be used later:

a, b [m]

coordinates of the centers of the osculating circles

e [m]

distance between the rolling devices

l, the [m]

lengths between bearing devices and joints

m

slope of tangents to osculating circles

s [m]

distance traveled

t [dry]

time

v [m / sec]

speed

x, y [m]

bearing center coordinates

G, H, K, L [m]

correction factors depending on the geometry of the rolling unit and the bearing device concerned

α [degrees]

variable angle relative to the axis of the body

αC [degrees]

variable angle corrected with respect to the body axis

β [degrees]

relative angle between the boxes

γ [degrees / m]

constant corresponding to a limit of a measurement interval.

ρ [m]

radius of osculating circles

ψ [degrees]

angle of the tangents to the first osculating circle

ψ '[degrees]

angle of the tangents to the second osculating circle

χ

matrix

The coordinates of the rolling stock centers are given by the following sectors:

We are looking for a circle with radius ρ and center (a, b) passing through a group of three points corresponding to the centers of the rolling devices. The equation of the circle is of the type: $$\text{((}\mathit{\text{x}}\text{-}\mathit{\text{at}}{\text{)}}^{\text{2}}\text{+ (}\mathit{\text{y}}\text{-}\mathit{\text{b}}{\text{)}}^{\text{2}}{\text{= <figure-callout id="2" label="ρ" filenames="imgf0001.png" state="{{state}}">ρ</figure-callout>}}^{\text{2}}$$

which can be written in the form of an arc function: $$\mathit{\text{y}}\text{= √}\overline{{\text{ρ}}^{\text{2}}\text{- (}\mathit{\text{x}}\text{-}\mathit{\text{at}}{\text{)}}^{\text{2}}}\text{+}\mathit{\text{b}}$$

Derivative $\text{m = y '(x)}$

of 1.6 is given by the equation:

The value of this derivative at point x gives the slope of the line tangent to the arc of a circle, at the point considered. Its angle with the abscissa is $$\text{ψ = arctg (m)}$$

The calculation of the coordinates of the center and the radius ρ of the osculating circles amounts to the resolution of a system with three equations 1.5 with three unknowns (a, b and ρ) and which can be written, for the first osculating circle, under the following matrix form:

and for the second circle:

The radii ρ1 and ρ2 of the osculating circles are calculated using equation 1.5.
The determination of the centers (a1, b1), (a2, b2) and of the radii ρ1 and ρ2 of the two circles allows the calculation of all the angles ψ thanks to equations (1.7) and (1.8).

   Les angles donnés par les équations (1.13) à (1.16) peuvent être corrigés par des fonctions empiriques dans le cas où la trajectoire réelle du tramway diffère trop d'une droite ou d'une courbe à rayon constant par exemple pour une entrée en courbe, un virage en S, etc.To determine the variable angles α between the rolling devices and the axes of the bodies, it is also necessary to deduce the relative angle β of the corresponding body. Furthermore for the rolling devices 9 and 10 belonging to the two circles, the final result is obtained by the average of the two angles ψ and ψ 'calculated for the first and the second circle respectively as follows: $$\begin{array}{c}\begin{array}{c}\begin{array}{}\text{(1.13)}\text{α1 = ψ1}\end{array}\\ \begin{array}{}\text{(1.14)}\text{α2 =}\frac{\text{1}}{\text{2}}\text{(ψ2 + ψ2 ')}\end{array}\\ \begin{array}{}\text{(1.15)}\text{α3 =}\frac{\text{1}}{\text{2}}\text{(ψ3 + ψ3 ') - β1}\end{array}\\ \begin{array}{}\text{(1.16)}\text{α4 = ψ4 '- (β1 + β2)}\end{array}\end{array}\end{array}$$

The angles given by equations (1.13) to (1.16) can be corrected by empirical functions in the case where the real trajectory of the tram differs too much from a straight line or from a curve with constant radius for example for an entry in curve , an S-turn, etc.

Pour Δβ2 ≠ 0

où $$\begin{array}{c}\begin{array}{c}\begin{array}{}\text{(1.21)}\text{Δβ = β(t + Δt) - β(t)}\end{array}\\ \begin{array}{}\text{(1.22)}\text{Δs = vΔt}\end{array}\end{array}\end{array}$$

Les intervalles définis par les différentes valeurs γ peuvent être affinés à volonté.The correction functions are based on the variation of the relative angles between the boxes β1 and β2, for a distance traveled Δs. Thus the corrected variable angles αjc supplied to the device for adjusting the rolling devices are of the form:
For β2 = 0 and Δβ2 = 0 and for:

For Δβ2 ≠ 0

or $$\begin{array}{c}\begin{array}{c}\begin{array}{}\text{(1.21)}\text{Δβ = β (t + Δt) - β (t)}\end{array}\\ \begin{array}{}\text{(1.22)}\text{Δs = vΔt}\end{array}\end{array}\end{array}$$

The intervals defined by the different γ values can be refined at will.

The correction factors Kj, Lj, Gj, Hj are dependent on the geometry of the tram. They are obtained empirically by comparing the theoretical results obtained using equations (1.13) to (1.16) with the virtual values obtained by computer simulation, for example.

In the diagram shown in FIG. 4, the calculation unit 41 is connected to the power supply 43 and receives the value of the relative angles β1 and β2 from the sensors 40 and the signal from the tachometer 44 of the rolling assembly. It delivers the calculated values of the variable angles αjc to the servo controllers 42. The latter control the jacks hydraulic 34 via a pump 45 so as to adjust the orientation of the wheels in accordance with the variable angle αjc calculated.

FIG. 5 represents a variant of a rolling assembly or train 50 also comprising three boxes 52, 53, 54. The first box 52 has a rolling device 58, the second box 53 two rolling devices 59, 60 and the third box 54 a single rolling device 61. The rolling assembly 50 is centrosymmetric and the lengths 11 and 13 are 7, 50m, the center distance e is 6.50m, the length la is 1.75m and the length 12 is 8.25m.

   Comme précédemment, le centre et le rayon des deux cercles osculateurs est calculé conformément aux équations 1.5 à 1.12, pour obtenir les angles variables : $$\begin{array}{c}\begin{array}{c}\begin{array}{}\text{(2.5)}\text{α1 = ψ1}\end{array}\\ \begin{array}{}\text{(2.6)}\text{α2 =}\frac{\text{1}}{\text{2}}\text{(ψ2 + ψ2')-β1}\end{array}\\ \begin{array}{}\text{(2.7)}\text{α3 =}\frac{\text{1}}{\text{2}}\text{(ψ3 + ψ3')-β1}\end{array}\\ \begin{array}{}\text{(2.8)}\text{α4 = ψ4'-(β1+β2)}\end{array}\end{array}\end{array}$$

   Les angles variables corrigés αjc délivrés au dispositif de réglage 42 des dispositifs de roulement sont de la forme :
Pour β2 = 0 et Δβ2 = 0 et pour :

   Avec la disposition des deux bogies centraux, la correction de α2 définie par l'équation (1.18) n'intervient pas. Ce simple exemple suffit à montrer la souplesse de la méthode qui s'applique sans autre à n'importe quelle géométrie.
Pour Δβ2 ≠ 0:

   Il est bien entendu que les modes de réalisation décrits ci-dessus ne présentent aucun caractère limitatif et qu'ils peuvent recevoir toutes modifications désirables à l'intérieur du cadre tel que défini par la revendication 1. En particulier, le réglage et le développement mathématique du contrôle précédemment exposé pourront être appliqués à des ensembles roulants, tramways, chemins de fer, métros comportant des rames et wagons ayant un nombre d'unités roulantes différent avec un nombre de dispositifs de roulement ou bogies différent. Dans le cas d' une rame à deux caisses seulement, le réglage se base alors sur un seul cercle osculateur et les équations 1.14 et 1.15 sont simplifiées. Seule la variation de l'angle relatif β1 interviendra dans la correction qui sera de la forme de l'équation 1.17 pour les trois angles αjc.The coordinates of the centers of the bearing devices are given by the following vectors:

As before, the center and the radius of the two osculating circles is calculated in accordance with equations 1.5 to 1.12, to obtain the variable angles: $$\begin{array}{c}\begin{array}{c}\begin{array}{}\text{(2.5)}\text{α1 = ψ1}\end{array}\\ \begin{array}{}\text{(2.6)}\text{α2 =}\frac{\text{1}}{\text{2}}\text{(ψ2 + ψ2 ') - β1}\end{array}\\ \begin{array}{}\text{(2.7)}\text{α3 =}\frac{\text{1}}{\text{2}}\text{(ψ3 + ψ3 ') - β1}\end{array}\\ \begin{array}{}\text{(2.8)}\text{α4 = ψ4 '- (β1 + β2)}\end{array}\end{array}\end{array}$$

The corrected variable angles αjc delivered to the adjustment device 42 of the rolling devices are of the form:
For β2 = 0 and Δβ2 = 0 and for:

With the arrangement of the two central bogies, the correction of α2 defined by equation (1.18) does not occur. This simple example is enough to show the flexibility of the method which applies without other to any geometry.
For Δβ2 ≠ 0:

It is understood that the embodiments described above are in no way limiting and that they can receive any desirable modification within the framework as defined by claim 1. In particular, the adjustment and the mathematical development of the control previously exposed may be applied to rolling assemblies, trams, railways, metros comprising trainsets and wagons having a different number of rolling units with a different number of rolling devices or bogies. In the case of a train with only two boxes, the adjustment is then based on a single osculator circle and equations 1.14 and 1.15 are simplified. Only the variation of the relative angle β1 will intervene in the correction which will be of the form of equation 1.17 for the three angles αjc.

If the train is made up of four or more boxes, the same logic is followed, namely the construction of several osculating circles, by group of three rolling devices. With the exception of the two end bearing devices, all are used for the interpolation of two osculating circles and the tangency angle is obtained by average according to the form (1.15). The correction functions (1.17) to (1.19) remain valid. The form (1.20) is applicable for the angles αjc belonging to a given body, by introducing the two relative angles β corresponding to the articulations of this body.

The invention applies of course to rolling units, trams, trains, trainsets, comprising any number of rolling devices, the latter being able to be arranged under the rolling units or between the rolling units. These rolling units may also have, alongside at least one rolling device with controlled orientation, a certain number of conventional bogies comprising at least two axles and whose orientation is given automatically.

The variable angles αj for each of the rolling devices can also be evaluated using more complex geometric functions than osculating circles.

If the rolling assembly is allocated to a certain route, it would also be possible to store the relative angles βm measured and to calculate and store the variable angles αjc calculated very precisely with refined correction functions comprising by example of the correction factors Gj, Hj, Kj, Lj modified as a function of the specific path stored in memory.

The second embodiment shown in FIG. 6 is constituted by a rolling assembly 65 comprising two boxes 66, 67 with rolling devices 68, 69, 70. This assembly could of course also include another number of boxes and devices of rolling. The originality of this embodiment consists in measuring, in addition to the relative angle β between the boxes 66, 67, the angular speed θ̇ or the angular variation of rotation of the boxes around their vertical axis by means of gyroscopes 72, 73 or any other device suitable for this purpose, such as gyroscopic sensors with piezoelectric elements. These gyroscopic sensor devices 72, 73 are connected to the calculation unit 41 to supply it with signals corresponding to the angular speed θ̇ or to the angular variation of rotation of the boxes around their vertical axis.

où
   Δβ_m est la variante de l'angle relatif β mesuré entre deux caisses successives pendant un intervalle de temps Δt entre deux mesures,
   θ̇_n est la vitesse angulaire d'une caisse n = 1,2 donnée autour de son axe vertical,
   N_j1 et N_j2 sont des facteurs dépendants de la géométrie de l'unité roulante et la position du dispositif de roulement (distance du dispositif de roulement à l'articulation l₁, l₂, entr'axe e).For each rolling device j, the angle αj between the axis of the body and the normal to the axis of the wheels is calculated in the calculation unit 41 according to the equation: $${\text{αj = N}}_{\text{d1}}{\text{Δβ}}_{\text{m}}{\text{+ N}}_{\text{d2}}{\dot{\text{θ}}}_{\text{not}}\text{Δt}$$

or
Δβ _m is the variant of the relative angle β measured between two successive cases during a time interval Δt between two measurements,
θ̇ _n is the angular speed of a box n = 1.2 given around its vertical axis,
N _j1 and N _j2 are factors depending on the geometry of the rolling unit and the position of the rolling device (distance from the rolling device to the joint l₁, l₂, center distance e).

All the measurements of Δβ _m and of θ̇ _n carried out for the positioning α _j of the bodywork device (s) of a body relate to this same body.

For each rolling device, there are a couple of factors N _j1 , N _j2 different. In the case of intermediate bodies of rolling assemblies with more than two bodies, the positioning angle αj of the rolling device (s) of these intermediate bodies is calculated taking into account the variation in angle Δβ _m of the joint la closer to the bearing (s) in question.

As the boxes are assumed to be infinitely rigid, the positioning of the gyroscopes inside the box does not influence the measurement of the speed of rotation θ̇ _n . The time interval Δt between measurements is typically 0.5 seconds.

By way of example, for the geometry corresponding to FIG. 6, we have the following values for the last bearing (70):
N₂₁ = 6
N₂₂ = 0.25
there being 8.005 m.

It is understood that excellent precision is obtained by placing a gyroscopic sensor on each box. However a cheaper solution would also allow to mount only a single gyroscopic device on a single body of the rolling assembly 65 and pass the measurements on to the other bodies. Instead of measuring the angular velocities θ̇ _n , it is of course also possible to measure the variations in the angle of rotation of a body around its vertical axis during given time intervals.

The adjustment members may be pneumatic, hydraulic or even mechanical jacks controlled by a stepping motor for example to obtain precise adjustment of the angles αj. In the case of a train with several wagons comprising articulated boxes, a calculation unit may be associated with each wagon or the train may only include a single calculation unit processing the data of all the wagons.

The device according to the invention has the great advantage of being upgradeable and adaptable to very specific conditions of use. In fact, any improved or specific mathematical processing can be integrated at low cost into the calculation unit 41 so as to be able to optimize at any time the adjustment of the orientation of the wheels without having to change the train from a mechanical point of view.

Claims (14)

Method for adjusting the orientation of rolling devices (8 to 11) with steerable wheels (15, 16) of a rolling assembly (1) on rails (25) comprising at least two rolling units (2 to 4), wagons or boxes composing a wagon, articulated and / or coupled to each other, the assembly being arranged on the rails by means of rolling devices (8 to 11) with wheels (15, 16) whose main planes (32) make variable angles (αj) with a direction parallel to the longitudinal axis (31) of the rolling unit (2 to 4) on which they are mounted, the method being carried out by adjusting said variable angles (αj) as a function of the curvature of the rails (25) so that the main planes (32) of the wheels are substantially coincident with tangents to the rails (25), characterized in that the relative angle (βm) is measured ) between the longitudinal axes (31) of at least two rolling units (2 to 4), in that the said angles var are calculated iables (αj) for at least one of the rolling devices (8 to 11) as a function of said relative angle (βm) measured and that its wheels (15,16) are oriented in accordance with said calculated variable angles (αj). Method according to claim 1, characterized in that the position of the rolling devices (8 to 11) is identified according to a coordinate system, that an arc of circle function of at least one osculating circle is determined passing through the centers of three rolling devices (8 to 11) and determining the value of said variable angles (αj) from the derivative of said circular arc function. Method according to claim 2, characterized in that the variable angles (αj) obtained by the osculator circle (s) are corrected by means of empirical correction function based on the variation

said relative angles (βm) for a distance traveled (Δs). Method according to one of claims 1 to 3, suitable for rolling assemblies comprising at least three rolling units (2 to 4) and at least four rolling devices (8 to 11), characterized in that a first relative angle (β1) between a first (2) and a second (3) rolling unit and a second relative angle (β2) between the second (3) and a third (4) rolling unit, by the fact that uses at least these two relative angles (β1, β2) to determine at least two functions of arcs of a circle of at least two osculating circles, a first passing through the centers of the first three rolling devices (8,9,10) , the second passing through the centers of the last three rolling devices (9,10,11), and by the fact that the value of said variable angles (αj) is determined from the derivatives of the two functions of an arc of a circle , the value of the variable angles (αj) of the rolling devices (9,10) belonging to two circles osculators being obtained by averaging the values obtained by each of the osculating circles. Method according to claims 3 and 4, characterized in that the correction functions are of the following form for at least three rolling units: - when the second relative angle (β2) and the variation (Δβ2) of this second relative angle are equal to zero:

- when the variation (Δβ2) of the second relative angle is not equal to zero.

or
αj = uncorrected calculated variable angle
αjc = corrected variable angle
Δβ1, Δβ2 = variation of the first and second relative angles in the time interval Δt
Δs = path traveled in the time interval Δt with a speed v
Ki, Li, Gj, Hj = predetermined correction factors depending on the geometry of the rolling assembly
γi, γi + 1 = limits defining the intervals for the values of the constants Ki, Li, Gj, Hj. Method according to claim 5, suitable for rolling assemblies comprising a number of rolling units greater than three, characterized in that several osculating circles are determined by group of three rolling devices, all of these rolling devices exception of those arranged at the end of the rolling assembly, used for the interpolation of two osculating circles and the relative angles being obtained by average of the values obtained for each of the two osculating circles, the variable angles obtained being corrected by means of said correction functions. Method according to claim 1, characterized in that the angular speed of rotation (θ̇ _n ) of rotation or the angular variation of rotation of at least one rolling unit (66,67) is measured around a vertical axis and that calculating said variable angle αj for at least one rolling device (68 to 70) taking into account this speed or angular variation measured and the difference of the relative angles (Δβ _m ) measured between the longitudinal axes of at least two rolling units (66,67) for a predetermined time interval (Δt). Method according to claim 7, characterized in that the variable angle (αj) for each of the rolling devices (68 to 70) is calculated according to the equation: $${\text{αj = N}}_{\text{d1}}{\text{Δβ}}_{\text{m}}{\text{+ N}}_{\text{d2}}{\dot{\text{θ}}}_{\text{not}}\text{Δt}$$

or
Δβ _m is the variation of the relative angle β measured between two successive rolling units during an interval of given time Δt.
θ̇ _n is the angular speed of rotation of a rolling unit n around a vertical axis, and
N _j1 and N _j2 are factors depending on the geometry of the rolling unit and the position of the rolling device on the rolling unit. Method according to claim 7 or 8, characterized in that said variation or angular speed (θ̇ _n ) is measured by means of a gyroscopic sensor device (72, 73). Rolling assembly on rails, the orientation of the wheels of which is adjusted according to the method defined in one of claims 1 to 9 and comprising at least two rolling units (2 to 4), wagons or boxes making up a wagon, articulated and / or coupled together. one to the other, the assembly being arranged on the rails (25) by means of rolling devices (8 to 11) with steerable wheels whose main plane (32) makes a variable angle (αj) with a direction parallel to the longitudinal axis (31) of the rolling unit on which they are mounted, characterized in that the rolling assembly comprises at least one adjustment device (30) intended to adjust said variable angle (αj) as a function the curvature of the rails (25) so that the main plane (32) of the wheels is substantially coincident with the tangent to the rails, this adjustment device (30) comprising at least one measuring member (40) capable of determining an angle relative (βm) between the axes lon gitudinal (31) of at least two rolling units, at least one calculation unit (41) intended to calculate the variable angles (αj) for each of the rolling devices as a function of said relative angle (βm), and of the adjustment members (34, 42) associated with the rolling devices ( 8 to 11) and likely to orient the wheels in accordance with said calculated variable angle (αj). Assembly according to claim 10, characterized in that it comprises m + 1 rolling units (2 to 4) and m measuring elements (40) intended to determine the m relative angles (βm) between the rolling units, these relative angles ( βm) being delivered to at least one calculation unit (41) for determining said variable angles (αj). Assembly according to claim 11, characterized in that the calculation unit (41) is adapted to correct the variable angles (αj) obtained by means of empirical correction functions. Assembly according to one of claims 10 to 12, characterized in that it comprises at least one gyroscopic sensor device (72, 73) arranged on at least one rolling unit (66, 67) intended to measure the angular speed (θ̇ _n ) or the angular rotation of the rolling unit around a vertical axis. Assembly according to claim 13, characterized in that each rolling unit (66, 67) is provided with a gyroscopic sensor device (72, 73) connected to said calculation unit (41).

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