METHOD FOR CONTROLLING WHEEL DEFORMATION, CORRESPONDING DEVICE AND CORRESPONDING SYSTEM COMPLETING THIS DEVICE

Description

[0001] The invention relates to wheel deformation control.

[0002] US patent 4,815,004 A describes a method for characterizing the forward or backward forces induced by a tire and calculating the tire's instantaneous effective radius. US patent 2003 / 160133 A1 describes a method for monitoring wheel deformation using a wheel displacement sensor about a vertical axis and a speed sensor.

[0003] Document EP 1 559 625 describes a method for monitoring the deformation of a railway wheel, comprising a step of obtaining the variation in the duty cycle of a toothed wheel during its rotation. The data used to obtain these variations are measured by a sensor to which a wheel deformation monitoring device is connected. The duty cycle is the ratio of the time the sensor is positioned opposite the tip of a tooth of the toothed wheel to the time the sensor is positioned opposite the tip of the tooth of the toothed wheel, plus the time the sensor is positioned opposite the preceding or following groove of that toothed wheel. The temporal variations in the duty cycle allow the relative deformations of the wheel being monitored to be determined.

[0004] However, such a deformation control method only allows the determination of a relative deformation of the wheel being controlled and only allows partial knowledge of the wheel's condition, which is not entirely satisfactory for ensuring the safety of railway vehicle operations.

[0005] To this end, the invention relates to a method for controlling the deformation of a wheel according to claim 1.

[0006] Thus, the wheel deformation control process not only allows the determination of the deformations of a wheel but also allows these deformations to be quantified and the actual shape of the wheel to be evaluated.

[0007] According to other advantageous aspects of the invention, the wheel deformation control method comprises one or more of the features of claims 2 and 3.

[0008] The invention further relates to a wheel deformation control system according to claim 4, another advantageous aspect of the system being claimed in claim 5.

[0009] The invention also relates to a vehicle conforming to claim 6.

[0010] The features and advantages of the invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings, in which: [ Fig 1 ] there figure 1 is a schematic representation of a railway vehicle equipped with a wheel deformation control system comprising a sensor and a wheel deformation control device according to the invention; [ Fig 2 ] there figure 2 is a schematic representation of a wheel equipped with a wheel deformation control system comprising a sensor and a wheel deformation control device according to the invention; [ Fig 3 ] there figure 3 is a schematic representation of the temporal evolution of the signal generated by the sensor; [ Fig 4 ] there figure 4 is an example of a weighting window used in the process of controlling the deformation of a wheel; [ Fig 5 ] there figure 5 is an example of the evolution of a signal generated by the sensor representing the measurement of the time between two successive teeth of a toothed wheel of the sensor shown in figure 2 , based on a measurement sample number; [ Fig 6 ] there figure 6 is an example of the evolution of a signal generated by the sensor as a function of the signal generated in figure 5 , representing the value of the wheel radius as a function of the sample number; and [ Fig 7 ] there figure 7 is a schematic representation of the deformation of a wheel obtained from the signal generated in figure 6 .

[0011] In the following description, we consider a right-handed orthonormal basis (X, Y, Z). The elevation direction Z is defined according to the height of the vehicle and corresponds, for example, to the vertical direction when the vehicle is on a horizontal track. The longitudinal direction X corresponds to the front-to-back direction of the vehicle, and the transverse direction Y corresponds to the width of the vehicle.

[0012] The terms "upper" and "lower" as well as "top" and "bottom" are defined with respect to the Z elevation direction. The terms "left" and "right" are defined with respect to the Y transverse direction in the normal direction of travel of the vehicle.

[0013] The wheel deformation control system 10 is shown schematically on the figure 1 is intended to be implemented on a railway vehicle 1 and aims to evaluate the radius of a wheel 4 in a multiplicity of angular positions.

[0014] Railway vehicle 1 is, for example, a locomotive, a wagon or a railcar.

[0015] The railway vehicle 1 comprises an axle 6, axle 6 comprising wheel 4 and shaft 7 ( figure 2 ). The wheel 4 is free to rotate about an axis YY of the shaft 7. When the railway vehicle 1 travels on a track, the wheel 4 is in contact and rolls on a rolling surface 8.

[0016] The wheel deformation control system 10 includes a wheel deformation control device 12 and a sensor 14 for measuring a parameter characterizing the angular velocity of the wheel 4 ( figure 1 ).

[0017] As shown by figure 2 The wheel comprises a rim 16 and a tread 18. The rim 16 connects the shaft 7 to the tread 18. The tread 18 is designed to bear and roll on the rolling surface 8 at a point of contact 19

[0018] The wheel 4 comprises a plurality of predefined angular positions. In particular, the wheel comprises n predefined angular positions θ i with i between 1 and n. A wheel radius R i is associated with each angular position θ i.

[0019] The sensor 14 includes a toothed wheel 20 and a sensing element 22. The sensor 14 is, for example, a component of an anti-lock device.

[0020] The gear 20 is free to rotate about the axis YY of the shaft 7. The gear 20 is rotationally fixed to the gear 4. The gear 20 comprises a multitude of teeth 24, regularly spaced circumferentially about the axis Y-Y'. In particular, the gear 20 comprises a number of teeth 24 greater than or equal to the number n of predefined angular positions. In a particular embodiment described herein, the gear comprises a number of teeth 24 equal to the number n of predefined angular positions. Each tooth 24 comprises a leading edge 26, a trailing edge 28, and a head 30 connecting the leading edge 26 to the trailing edge 28.

[0021] The sensing member 22 is adapted to detect the passage of the teeth 24 of the gear 20 during the rotation of the wheel 4. The sensing member 22 is, for example, placed opposite the toothed edge of the gear.

[0022] The detection element 22 detects the passage of teeth magnetically. In an alternative embodiment, the detection element 22 detects the passage of teeth optically.

[0023] The sensing element 22 is adapted to detect the cutting edges of the teeth 24 of the gear. More specifically, the sensing element 22 is adapted to detect the leading edge 26 and / or the trailing edge 28 of the teeth 24 of the gear. In the embodiment shown, the sensing element 22 is adapted to detect the leading edge 26 of the teeth 24.

[0024] The sensing device generates, for example, a signal s over time, as represented in the figure 3 .

[0025] The sensing element 22 of the sensor 14 is configured to obtain, while the wheel 4 rolls on the running surface 8, and for each angular position θi, a parameter characterizing the angular velocity of the wheel 4 when the wheel is in contact with the running surface at said predefined angular position. More specifically, the sensing element 22 of the sensor 14 is angularly offset from the portion 19 of the wheel in contact with the ground by an angle A. The angular velocity measured for the leading edge of the tooth located at θi - A thus characterizes the angular velocity of the wheel when it is in contact with the running surface at position θi, as illustrated in figure 2 .

[0026] According to the invention, the sensing element 22 is configured to obtain a direct time deviation ΔT i for each angular position θ i . The parameter characterizing the angular velocity of the wheel 4 for an angular position θ i is then the direct time deviation ΔT i .

[0027] The direct time difference ΔT i corresponds to the time difference between the detection of the leading edge 26 of two teeth 24 of the gear. In the embodiment presented, the direct time difference ΔT i is the time difference between the detection of the leading edge of two consecutive teeth of the gear, and more specifically, the time difference between the detection of the leading edge 26 of two consecutive teeth of the gear. The direct time difference ΔT i is then the time difference between the detection of the leading edge of the tooth located at angular position θ i- A and the detection of the leading edge of the immediately preceding tooth. This direct time difference ΔT i thus corresponds, in the case where there are as many teeth 24 as there are positions θ i, to the time difference between the passage from angular position θ i to the contact point 19 and the passage from angular position θ i-1 to the contact point.

[0028] An example of the measurement of the time between two successive teeth 24 made by the sensing member 22 is presented, for example, in figure 5 , which represents the time between two successive teeth 24 as a function of a measurement sample number (each measurement sample being associated with an angular position θ i ). On the figure 5 , a first curve C1 represents the measurement of the direct time difference ΔT i between two successive teeth 24 and a second curve C2 represents a filtered time difference ΔT filti whose calculation is described later, for a train traveling at 40km / h with slight acceleration, a wheel with a nominal diameter of 1 meter and a number of teeth 24 of toothed wheel equal to 80.

[0029] The wheel deformation control device 10 includes a calculation module 32.

[0030] Calculation module 32 is configured to calculate the value of the wheel radius Ri for each predefined angular position θi using the parameter characterizing the angular velocity obtained for the predefined angular position. In particular, the calculation module is configured to calculate the value of the wheel radius Ri for the position θi using the direct time deviation ΔTi associated with the angular position θi.

[0031] Calculation module 32 is also configured to calculate the value of the wheel radius Ri for the predefined angular position θi using the filtered time difference ΔTfilti represented on the figure 5 , associated with the predefined angular position θ i . The filtered time deviation ΔT filti associated with the predefined angular position θ i corresponds to a weighted average of direct time deviations ΔT i for a multiplicity of predefined angular positions θ i .

[0032] The calculation module 32 is, according to the invention, configured to calculate the filtered time deviation ΔT filti by weighting the direct time deviations ΔT i for a multiplicity of predefined angular positions using a Hann window. Such a weighting window is, for example, visible in figure 4 where p is a weighting coefficient. Calculation module 32 is specifically configured to perform a weighted average of the k direct time deviations whose angular position precedes the predefined angular position θi and the k direct time deviations whose angular position follows the predefined angular position, with k a natural number less than half of n. In other words, the filtered time deviation ΔTfilti for a predefined angular position θi is calculated using the direct time deviations ΔTi for the angular positions between θik and θi+k. In particular, and in the preferred embodiment, k is the natural number closest to one-eighth of the number of teeth n. The filtered time deviation ΔTfilti is thus calculated using the direct time deviations ΔTi associated with the angular positions θi within the quarter-wheel surrounding the predefined angular position θi.

[0033] Alternatively, a rectangular window or a Hamming window or a Blackman window are suitable for use instead of the Hann window.

[0034] Calculation module 32 is configured to calculate the value of the radius Ri of wheel 4 for each predefined angular position as the product of a predetermined wheel radius, for example, an average wheel radius Rm, and the ratio between the direct time deviation ΔTi and the filtered time deviation ΔTfilti obtained for said predefined angular position θi. The calculation module is configured to calculate the value of Ri of wheel 4 for each predefined angular position using the following equation. R i = R m . ΔT i ΔT filti

[0035] An example of the estimated radius value for the direct time deviation and the filtered time deviation for the case of curves represented in figure 5 For a train traveling at 40 km / h with slight acceleration, a wheel with a nominal diameter of 1 meter and a gear with 24 teeth equal to 80 is given by the graph shown in figure 6 representing the value of the estimated radius based on the sample number.

[0036] There figure 7 allows visualization of the wheel deformation obtained via the graph shown in figure 6 with several overlapping wheel rotations which allow the elimination of measurement noise. A faceted deformation of the wheel is thus observed in this example.

[0037] A method for controlling wheel deformation according to the invention will now be presented. The wheel deformation control system 10 described previously is specially adapted to implement the method now presented. The method now presented is also specially adapted to be implemented by the wheel deformation control system 10 described previously.

[0038] The process includes a step of obtaining the parameter characterizing the angular velocity of the wheel for the plurality of predefined angular positions θ i followed by a step of calculating a radius value R i of the wheel 4 for each predefined angular position θ i.

[0039] The obtaining step includes obtaining, for the plurality of predefined angular positions θ i on the wheel, while the wheel 4 rolls on the rolling surface 8, a parameter characterizing an angular velocity of the wheel when the wheel 4 is in contact with the rolling surface 8 by said predefined angular position θ i.

[0040] The obtaining step is implemented in particular when the railway vehicle travels at a substantially constant speed on the running surface 8. The obtaining step is preferably implemented when the wheel 4 rolls on the running surface 8 without slipping.

[0041] The acquisition step includes the measurement by sensor 14 of the parameter characterizing the angular velocity of wheel 4.

[0042] During the acquisition step, the sensor 14 successively measures the direct time difference ΔT i for each predefined angular position θ i. The direct time difference ΔT i is measured in particular when a predefined angular position θ i is in contact with the rolling surface 8, or in other words when the sensing element 22 detects the leading edge 26 of a tooth 24 in a position θ i - A angularly offset from the position θ i of angle A. The time difference ΔT i then corresponds to the time elapsed between the detection of the leading edge 26 of a tooth 24 in the position θ i - A and the detection of the leading edge 26 of the preceding tooth 24.

[0043] Following the acquisition of the direct time error values ​​ΔT i, a radius value R i for each angular position θ i is calculated during the calculation step. This calculation step is implemented in particular by calculation module 32.

[0044] The calculation of each wheel radius Ri uses the direct time deviation ΔTi obtained for each angular position θi. The calculation of each wheel radius Ri for the predefined angular position θi also uses the filtered time deviation ΔTfilti, the filtered time deviation being a weighted average of direct time deviations ΔTi for a multiplicity of predefined angular positions θi. The filtered time deviation ΔTfilti is calculated, in particular, by weighting the direct time deviations ΔTi for a multiplicity of predefined angular positions using a Hann window.

[0045] According to a particular embodiment, the obtaining step extends, for example, over several wheel revolutions. Advantageously, the obtaining step extends over at least four wheel revolutions. For each wheel revolution, a direct time deviation ΔTi for a predefined angular position θi is obtained. The direct time deviation ΔTi specific to a wheel revolution allows the calculation of a filtered time deviation ΔTfilti specific to a wheel revolution and a wheel radius Ri specific to a wheel revolution for a predefined angular position θi.

[0046] The wheel deformation control process then includes, during the calculation step, the calculation of at least four wheel radius values ​​Ri for each predefined angular position θi. The calculation step includes the calculation of a consolidated wheel radius value Ric for each predefined angular position, the consolidated wheel radius value Ric for each predefined angular position θi being calculated using the at least four wheel radius values ​​Ri calculated for each predefined angular position θi.

[0047] The wheel deformation control method according to the invention not only makes it possible to determine the deformations of a wheel but also to quantify these deformations and to evaluate the actual shape of the wheel. In particular, it makes it possible to determine the wheel's proper radius Ri for each predefined angular position θi.

[0048] The use of a sensor 14 comprising a toothed wheel 20 and a sensing element 22 is particularly advantageous since it allows economical control of wheel deformations, the sensor 14 being for example a component of an anti-lock device of the railway vehicle.

[0049] Calculating the radius value using the filtered time difference ΔT filti and in particular using a Hann window improves the accuracy of calculating wheel deformations 4.

[0050] Calculating a consolidated wheel radius R ic also improves the accuracy of wheel deformation calculations by excluding potential anomalies during measurement.

Claims

1. A method for controlling the deformation of a wheel (4), the method comprising the following steps: - while the wheel (4) rolls on a rolling surface (8), obtaining, for a plurality of predefined angular positions (θi) on the wheel, a parameter characterising an angular speed of the wheel (4) when the wheel (4) is in contact with the rolling surface (8) at said predefined angular position (θi); and - calculating a radius value (Ri) of the wheel (4) for each predefined angular position (θi) using the parameter characterising the angular speed obtained for said angular position (θi), wherein the parameter characterising the angular speed of the wheel (4) is measured by a sensor (14), the sensor (14) comprising a gear wheel (20) and a detection member (22) configured to detect an edge (26, 28) of each tooth of the gear wheel, the parameter characterising the angular speed of the wheel (4) being a direct time difference for the predefined angular position (θi), the direct time difference being the time difference between the detection of the edge (26, 28) of two teeth (24) of the gear wheel (20), the two teeth (24) advantageously being two consecutive teeth (24) of the gear wheel (20), calculating a radius value (Ri) of the wheel for each predefined angular position (θi) using a filtered time difference, the filtered time difference being a weighted average of direct time differences for a multiplicity of predefined angular positions (θi), the filtered time difference being calculated by weighting the direct time differences for a multiplicity of angular positions (θi) predefined by a Hann window.

2. The method for controlling the deformation of a wheel according to claim 1, wherein calculating a radius value (Ri) of the wheel for each predefined angular position (θi) is the product of a predetermined wheel radius and the ratio between the direct time difference and the filtered time difference obtained for said predefined angular position (θi).

3. The wheel deformation control method (4) according to claim 1 or 2, the method comprising calculating at least four wheel radius values (Ri) for each predefined angular position (θi), a consolidated wheel radius value for each predefined angular position (θi) being calculated using at least four wheel radius values calculated for each predefined angular position (θi).

4. A system (10) for controlling the deformation of a wheel (4) comprising a sensor (14) and a device (12) for controlling the deformation of a wheel (4) connected to the sensor (14), the sensor (14) being configured to obtain, while the wheel (4) rolls on a rolling surface (8), for a plurality of predefined angular positions (θi) on the wheel (4), a parameter characterising an angular speed of the wheel (4) when the wheel (4) is in contact with the rolling surface (8) at said predefined angular position (θi), the device (12) comprising a module (32) for calculating a radius value (Ri) of the wheel (4) for each predefined angular position (θi) using the parameter characterising the angular speed obtained for said angular position (θi), wherein the parameter characterising the angular speed of the wheel (4) is measured by the sensor (14), the sensor (14) comprising a gear wheel (20) and a detection member (22) configured to detect an edge (26, 28) of each tooth of the gear wheel, the parameter characterising the angular speed of the wheel (4) being a direct time difference for the predefined angular position (θi), the direct time difference being the time difference between the detection of the edge (26, 28) of two teeth (24) of the gear wheel (20), the two teeth (24) advantageously being two consecutive teeth (24) of the gear wheel (20), calculating a radius value (Ri) of the wheel for each predefined angular position (θi) using a filtered time difference, the filtered time difference being a weighted average of direct time differences for a multiplicity of predefined angular positions (θi), the filtered time difference being calculated by weighting the direct time differences for a multiplicity of angular positions (θi) predefined by a Hann window.

5. The system (10) for controlling the deformation of a wheel (4) according to claim 4, intended to be on board a rail vehicle (1).

6. A vehicle, in particular a railvehicle, comprising at least one wheel and a system for controlling the deformation of the wheel according to claim 4 or 5.