Method for determining at least one shape parameter of a railway track and system for implementing the method
The method addresses the limitations of conventional systems by using a vehicle with an inertial unit and relative orientation measurement devices to calculate absolute orientation components through spatial integration, effectively determining railway track shape at low speeds with improved accuracy.
Patent Information
- Application Number
- JP2024560599
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-05-28
- Filing Date
- 2023-05-25
- Publication Date
- 2025-06-12
AI Technical Summary
Conventional inertial measurement systems for determining railway track shape are limited by the need for minimum speed, leading to systematic inaccuracies and biases at low speeds or during stops, thereby restricting their application to low-speed operations like track renovation.
A method involving a vehicle equipped with an inertial unit, a device for measuring relative orientation components of the rails, and odometers, which calculates absolute orientation components through a single spatial integral, eliminating time-related effects like drift, and applies high-pass or band-pass filters to improve accuracy.
This approach enables accurate determination of railway track shape parameters at low speeds, including during stops, by eliminating drift and enhancing measurement precision, thus expanding the system's applicability beyond high-speed operations.
Smart Images
Figure 2025517873000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates in particular to the determination of specific parameters of the shape of a railway track, for the purpose of inspecting or controlling the railway track, for example during laying, monitoring, maintenance or renovation.
Background Art
[0002] The main shape parameters of the track defined by the EN13848 standard are as follows. - Gauge: the minimum distance between the rails up to 14 mm below the running surface - Longitudinal level: the variation of the continuous running surface height with respect to the reference height, which is a sliding average - Cant: the height difference between the running surfaces of the left and right rails - Alignment: the variation in the horizontal plane of the position of each row of rails with respect to the reference position, which is a sliding average - Twist: the variation within the cant
[0003] The measured values of the longitudinal level, alignment, and twist are measured values of variation. They are relative measured values, in contrast to absolute measured values such as the cant and gauge. According to the standard, the longitudinal level and alignment are studied within different wavelength ranges. - D1: 3 m to 25 m - D2: 25 m to 70 m - D3: 70 m to 150 m
[0004] To determine the shape of a railway track, it is known that an instrumentation vehicle travels on the track, and an inertial unit that provides gyro measurements of the yaw angle, pitch angle, and roll angle, as well as acceleration measurements along three axes, is attached to the chassis of its body or bogies. The vehicle is also equipped with a detection laser for determining the relative position of the chassis, and thus the inertial unit, with respect to the railway track train.
[0005] Such a non-contact inertial measurement device is used in particular in the IRIS 320 (TGV d’Inspection Rapide des Installations de Securite a 320km / h) high-speed measurement train that measures all track geometry parameters at speeds up to 360 km / h.
[0006] One drawback of this system is that it imposes a minimum speed on the measurement vehicle on the track. At low speeds, the acceleration measurement signals that provide access to all displacements in three dimensions of space by double time integration are weak and do not utilize the full dynamic range of the sensors. As a result, the acceleration measurements potentially suffer from systematic inaccuracies or biases that are amplified by the double integration operation up to the point of generating a constant time drift when estimating all displacements in three dimensions. In practice, it should be noted that these drifts can no longer be ignored below a certain running speed which can actually be 60 km / h, so it is impossible to obtain measurements in the case of running with low speed or stops. Therefore, the field of application for measurement vehicles equipped with such conventional inertial measurement systems is limited. In particular, they cannot be used at track renovation sites that proceed at working speeds far below the minimum operating speed of the measurement device and may have zero speed during stops of arbitrary duration.
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0007] The object of the present invention is to provide a means for determining the shape of a railway track with a practically desirable accuracy that overcomes the drawbacks of the prior art and can be implemented at low moving speeds including during stops of arbitrary duration.
MEANS FOR SOLVING THE PROBLEM
[0008] According to a first aspect of the present invention, a method is proposed for determining at least one geometry parameter of a railway track having two tracks. - A vehicle equipped with an inertial unit, a device for measuring at least one relative orientation component of at least one of two rows of rails with respect to the inertial unit, and one or more odometers is made to move on a track, - Successive values of at least one absolute orientation component of the inertial unit in a stationary reference coordinate system are determined as a function of signals generated at least by the inertial unit, - For the rails of at least one observed row of the two rows of rails, preferably for each of the two rows of rails considered as the rails of the observed row, - Successive values of the curvilinear abscissa of the vehicle on the rails of the observed row are determined as a function of signals generated at least by the odometer, - Successive values of at least one relative orientation component of the rails of the observed row with respect to the inertial unit are determined as a function of signals generated at least by the measuring device, - Successive values of at least one absolute orientation component or absolute positioning component of the rails of the observed row are calculated as a function of the successive values of at least the absolute orientation components of the inertial unit and the relative orientation components of the rails of the observed row with respect to the inertial unit, - A function s→G(s) is constructed that links at least some of the successive curvilinear abscissa values to the associated values among the successive values of the absolute orientation component or absolute positioning component of the rails of the row observed in space, - A high-pass linear filter or a band-pass linear filter is applied to the function s→G(s) to construct a filtered function s→F(s), - For a series of current curvilinear abscissa values l among the curvilinear abscissa values, an integral I(l) is estimated over a given curvilinear abscissa interval bounded by a reference curvilinear abscissa value l 0 of the filtered function and the current curvilinear abscissa value l.
Number
[0009] Instead of performing a double integral of each observed row of rails to a filtered function that links the curvilinear abscissa of the vehicle to an absolute orientation component or an absolute positioning component, a single spatial integral is performed, by which all time-related effects, specifically the drift effect, are eliminated.
[0010] In practice, successive curvilinear abscissa values are not necessarily determined at regular distance intervals. Specifically, various signals can be sampled, preferably synchronized, at regular time intervals in order to obtain a good agreement between the values determined from signals from an inertial measurement unit, an odometer, and measuring instruments.
[0011] The inertial unit must have sufficient accuracy to provide the absolute orientation components within a stationary reference coordinate system, i.e., without drift. Thus, it is a type of control unit in which a gyroscope can detect the projection of the Earth's rotation and an accelerometer can detect the projection of gravity.
[0012] By applying a band-pass filter or a high-pass filter to the input function s → G(s) before the integration operation, potential digital instabilities resulting from the integration of the continuous components of the input function are avoided. The linear filter used is preferably a finite impulse response filter of any order N, preferably 2 or more.
[0013] Preferably, the linear filter is preferably a band-pass filter in one of the following three bands: 3m - 25m, 25m - 70m, 70m - 150m, or an arrow calculation function. In practice, the same function s → G(s) can of course be used to construct several filtered functions in parallel for different wavelength bands or filter types.
[0014] In practice, the estimated value of the integral is obtained by a discrete sum, and preferably, the integral I(l) is estimated by a Riemann sum or the trapezoidal method over a given interval with a step size of less than 25 cm, preferably less than 1 cm.
[0015] According to one embodiment, the operation of calculating the continuous value of at least one absolute orientation component or absolute positioning component of the rails of the observed column is composed, at successive time points, of the instantaneous value of the absolute orientation component of the inertial unit and the algebraic sum of the simultaneous instantaneous values of the relative orientation components of each of the rails of the observed column with respect to the inertial unit.
[0016] In one embodiment, the relative orientation component of the rails of the observed column with respect to the inertial unit is the orientation angle in the horizontal plane, the absolute orientation component of the inertial unit is the yaw angle, and the integral I(l) is the alignment parameter. ψ R is the instantaneous value of the angle determined by the measuring device in the horizontal plane between the longitudinal direction of the inertial measurement unit and the direction of the rails of the observed column, and ψ C is the instantaneous value of the yaw angle simultaneously determined by the inertial unit. In this case, the absolute orientation component ψ A of the rails of the observed column can be expressed as an algebraic sum.
Number
[0017] In another embodiment, the relative orientation component of the rails of the observed column with respect to the inertial unit is the orientation angle with respect to the vertical longitudinal plane (V) of the vehicle, the absolute orientation component of the inertial unit is the pitch angle, and the integral I(l) is the longitudinal level parameter. θ R is the instantaneous value of the angle determined by the measuring device in the vertical longitudinal plane between the longitudinal direction of the inertial measurement unit and the direction of the rails of the observed column, and θ C is the instantaneous value of the pitch angle simultaneously determined by the inertial unit. In this case, the absolute orientation component θ A of the column of rails can be expressed as an algebraic sum.
Number
[0018] Preferably, to obtain the intrinsic alignment coordinates and the intrinsic longitudinal level coordinates, the continuous values of at least one absolute orientation component of one of the two observed rail columns are calculated, the function s→G(s) is constructed, a linear filter is applied, the filtered function s→F(s) is constructed, and the operation of estimating the integral I(l) is executed in parallel.
[0019] In one embodiment, the measuring device delivers at least two simultaneous signals for measuring the lateral distance between two reference points on the vehicle and the observed rail column, and the two reference points are at a distance (A) greater than 250 mm, preferably greater than 500 mm from each other. When A is the distance between two reference points for the same observed rail column, y 1 and y 2 are the lateral distances measured between the observed rail column and each reference point, and when y 1 =y 2 assuming that the longitudinal axis of the inertial unit is aligned with the longitudinal axis of the rail column, the measuring device uses the following formula to access the relative orientation component constructed by the yaw angle ψ R of the inertial unit with respect to the observed rail column.
Equation
[0020] In one embodiment, the measuring device delivers at least two simultaneous signals for measuring the longitudinal distance between two reference points on the vehicle and the observed rail column, and the two reference points are separated from each other by a distance (B) greater than 250 mm, preferably greater than 500 mm. When B is the distance between two reference points for the same observed rail column, z 1 and z 2 are the longitudinal distances measured between the observed rail column and each reference point, and when z 1 =z 2 assuming that the longitudinal axis of the inertial unit is aligned with the longitudinal axis of the rail column, the measuring device uses the following formula to access the pitch angle θ of the inertial unit with respect to the observed rail columnR Access the relative orientation component constructed by
Number
[0021] The sensors of the measuring device can operate on different principles (optical, magnetic, capacitive, etc.) that operate linearly and optimally within a relatively narrow operating range. Therefore, it is beneficial to ensure that the positioning of the vehicle on the track is always close to the "ideal" alignment position in both the longitudinal and transverse directions. For this purpose, at least one actuator for correcting the alignment of the vehicle on the track is used to reduce the drift between the signal generated by the measuring device and a predetermined value, or to reduce the drift between the continuous values of the relative orientation components of the rails of the observed train and the predetermined values of the relative orientation components of the rails of the observed train. It can be controlled as a function of the signal generated by the measuring device or the continuous values of the relative orientation components of the rails of the observed train observed by the inertial unit. The correction operation is particularly useful for vehicles running on a single pair of wheels.
[0022] In one embodiment, the operation of determining the continuous curvilinear abscissa values of the vehicle on the rails of the observed train is performed as a function of the signal generated by at least the odometer associated with the rails of the observed train among the odometers. If each column of the rails is associated with at least one odometer, this operation can be performed for each column of the rails.
[0023] In one embodiment, the operation of determining the continuous curvilinear abscissa values of the vehicle on the rails of the observed train is performed as a function of the signal generated by an odometer not associated with the rails of the observed train among at least the odometers and the signal generated by the measuring device. If only one of the columns of the rails is associated with an odometer, this operation can be performed for the other columns.
[0024] In practice, the wheel to which the odometer is connected may temporarily lose contact with the rails of the observed train, in which case the generated signal no longer provides reliable information regarding the position of the vehicle relative to the rails of the observed train. In one embodiment, an odometer failure is detected by comparing the longitudinal acceleration value generated by the inertial unit with an average acceleration value determined as a function of the signal generated by the odometer, and / or by comparing the angular velocity value about the vertical axis generated by the inertial unit with an angular velocity value estimated from the signal generated by the odometer. Preferably, when a failure is detected, a safety procedure is executed and the successive curvilinear abscissa values of the vehicle on each of the two rails are determined as a function of at least the acceleration signal or the angular velocity signal generated by the inertial unit.
[0025] Another aspect of the present invention is a system for implementing the method according to the first aspect of the present invention or one of its embodiments, comprising a vehicle capable of traveling on a railway line having two parallel rows of rails, the vehicle being equipped with an inertial unit having at least three gyroscopes and three accelerometers, a device for measuring the relative orientation of each of the two rows of rails with respect to the inertial unit, and one or more odometers, the system further comprising computing means programmed to calculate successive values of at least one absolute orientation component or absolute positioning component of the observed row of rails out of the two rows of rails, construct a function s→G(s), apply a linear filter, construct a filtered function s→F(s), and execute an operation for estimating an integral I(l).
[0026] In one embodiment, the measuring device associated with each of the two rows of rails comprises at least two sensors for measuring the lateral distance between the row of rails associated with two reference points on the vehicle, the two reference points being separated from each other by a distance (A) greater than 250 mm, preferably greater than 500 mm. Each sensor is dedicated to measuring the lateral distance at one of the reference points.
[0027] In one embodiment, the measuring device associated with each of the two rows of rails comprises at least two sensors for measuring the vertical distance between the rows of rails associated with two reference points on the vehicle, the two reference points being separated from each other by a distance (B) greater than 250 mm, preferably greater than 500 mm. Each sensor is dedicated to measuring the vertical distance at one of the reference points.
[0028] Other principles for measuring the relative orientation of the inertial units with respect to each row of rails are also predictable. In one embodiment, the measuring device comprises at least one, preferably at least two, cameras for detecting one or more linear laser beams projected onto each row of rails. For example, each camera can capture the position of the laser line projected onto the rails of the observed row, and the measuring device determines the relative vertical and horizontal positions between the rails of the observed row and the camera, which are arranged within the reference coordinate system of the inertial unit, by triangulation.
[0029] In another embodiment, the measuring device comprises at least one, preferably at least two, laser rangefinders for scanning the rows of rails of the track. According to the principle of laser telemetry, the distance is given by measuring the delay between the emission of a pulse and the detection of the reflected pulse. The projected laser beam scans a plane of space that can cover both rows of rails, and is guided by a rotating mirror that triangulates each row of rails to derive measurements of the horizontal and vertical distances. Two laser rangefinders arranged at a distance from each other in the longitudinal direction of the vehicle make it possible to obtain the eight required dimensions, namely four horizontal distances and four vertical distances.
[0030] Optionally, the measuring device may further comprise a track gauge sensor, although this dimension can be estimated by measuring the horizontal distance between various reference points and the two rows of rails. Optionally, the measuring device may further comprise a track cant sensor.
[0031] In one embodiment, the vehicle is a two-wheeled vehicle driven by the machine and connected to the machine via at least three links for controlling the attitude and alignment of the vehicle as a function of the relative orientation components.
[0032] In an alternative embodiment, the vehicle is a vehicle having at least four wheels. [Brief description of the drawings]
[0033] Other features and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, in which: FIG.
[0034]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
[0035] For greater clarity, identical or similar elements are identified by the same reference signs in all figures. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Figures 1 and 2 show a system 10 for determining at least one shape parameter of a track 1 having two rails 2, comprising a vehicle 12 coupled to a railway machine 14 that can travel on the track and which can in particular be a machine for laying, repairing or replacing the track. The vehicle 12 is in this case a carrier vehicle comprising a rigid chassis 16 mounted on a single pair of wheels 18, possibly with a primary suspension therebetween. Preferably, the carrier vehicle 12 has no propulsion means and is only pulled or pushed by the railway machine 14 when moving along the track. The coupler 20 connecting the carrier vehicle 12 to the railway machine 14 is here constituted by connections to two ball joints 22 and two cylinders 24 in order in particular to enable adjustment of the angular orientation of the chassis 16 relative to the railway machine 14 and the track 1 in the vertical and transverse planes. However, it should be noted that the orientation of the chassis 16 relative to the track 1 may be adjusted by other adjustment means, in particular by controlling an actuator arranged on the primary suspension between the chassis 16 and the wheels 18. It should also be noted that the wheels 18 are preferably independent in the sense that they rotate independently of each other.
[0037] The carrier vehicle 12 is equipped with various measuring devices, including at least one odometer 26 attached to one of the wheels 18 of the carrier vehicle 12 in order to determine, for example, the distance travelled by the carrier vehicle 12 along a row of rails 2 on which the wheels 18 run, or the curvilinear abscissa of the carrier vehicle 12 relative to this row of rails 2. Preferably, each of the two wheels 18 is equipped with an odometer 26 so that the curvilinear abscissa of the carrier vehicle 12 relative to each of the two rows of rails 2 of the track 1 can be directly determined.
[0038] The carrier vehicle 12 further comprises measuring devices 28 for determining the orientation of the chassis 16 relative to each row of rails 2 in at least one reference plane of the chassis 16, preferably at least two orthogonal planes, namely a horizontal plane H and a longitudinally vertical plane V.
[0039] For this purpose, the measuring device associated with at least one of the two rows of rails 2, preferably both of the two rows of rails 2, comprises at least two sensors for measuring the lateral distance 30 between the row of rails and two reference points of the vehicle, the two reference points being spaced apart from each other by a distance A as shown in FIG. 2. y 1 and y 2 are the lateral distances measured between the observed row of rails 2 and each reference point 30, then y 1 =y 2 When this is the case, assuming that the longitudinal axis of the chassis 16 is aligned with the longitudinal axis of the row of rails 2, the measuring device uses the following formula to access the relative orientation component constructed by the yaw angle ψ of the chassis with respect to the row of rails observed in the horizontal plane R constructed by
Number
[0040] The accuracy of the results naturally increases with a distance A that is preferably greater than 250 mm and more preferably greater than 500 mm.
[0041] In a similar manner to the orientation of the transporter chassis observed in the vertical plane V, the measuring device associated with at least one of the two rows of rails 2, preferably both of the two rows of rails 2, comprises at least two sensors for measuring the longitudinal distance 32 between the row of rails associated with two reference points of the vehicle, as shown in FIG. 1. When B is the distance between two reference points 32 for the same observed row of rails, selected to be preferably greater than 250 mm and more preferably greater than 500 mm, z 1 and z 2 are the longitudinal distances measured between the observed row of rails and each reference point, and z 1 =z 2 When this is the case, assuming that the longitudinal axis of the chassis 16 is aligned with the longitudinal axis of the row of rails, the measuring device uses the following formula to access the pitch angle θ of the chassis with respect to the row of rails observed in the vertical longitudinal plane of the chassis RAccess the relative orientation component constructed by
Number
[0042] The distance to the row of Rail 2 can be measured using the non-contact sensors 30, 32 shown in Figure 3, including proximity sensors such as inductive sensors, photoelectric sensors, magnetic sensors, capacitive sensors, or ultrasonic sensors. To avoid interference between sensors targeting the same area of the row of rails, two different types of sensors can be selected for lateral and longitudinal distance measurements.
[0043] An inertial unit 34 having at least three gyroscopes and three accelerometers is attached to the non-deformable chassis 16 of the carrier vehicle 12, and this inertial unit 34 is called a precision inertial unit in the sense that it can deliver an absolute orientation signal in a stationary reference coordinate system, that is, without drift. Therefore, it is a type of control unit in which the gyroscope can detect the projection of the rotation of the earth and the accelerometer can detect the projection of gravity.
[0044] In this way, the carrier vehicle 12 can be used to determine the absolute orientation of the inertial unit 34 in the stationary reference coordinate system and the relative orientation of each row of Rail 2 with respect to the chassis 16, and thus with respect to the inertial unit 34 attached to the chassis 16. To estimate the shape parameters of each row of Rail 2 in the absolute reference coordinate system from these measurement data, the specific procedures shown in Figures 4 and 5 are proposed.
[0045] When the carrier vehicle 12 is traveling at a low speed, which may not be constant, especially at a speed of less than 10 km / h, and when the machine 14 may decelerate or stop for a long time at the pace of the work being done on the track 1, the signals from the odometer 26, the measuring device 28, and the inertial unit 34 are sampled simultaneously at regular time intervals.
[0046] The continuous values of at least one absolute orientation component of the inertial unit 34 in the stationary reference coordinate system, for example the continuous values of the roll angle and / or the continuous values of the pitch angle, are determined as a function of at least the signals generated by the inertial unit 34 (operation 40).
[0047] For at least one observed row of rails 2 out of two rows of rails, preferably for each of the two rows of rails 2 considered to be the observed row of rails, the continuous curvilinear abscissa values of the vehicle on the observed row of rails 2 are determined as a function of at least the signals generated by the odometer 26 associated with the observed row of rails (operation 42).
[0048] Based on at least the signals generated by the measuring device 28, at least one relative orientation component of the observed row of rails 2 with respect to the inertial unit 34, preferably both of the above-mentioned components, i.e., the yaw angle ψ of the chassis with respect to the observed row of rails 2 R , and the pitch angle θ of the chassis with respect to the observed row of rails R for which continuous values are determined (operation 44).
[0049] Based on these factors, it is possible to calculate the continuous values of at least one absolute orientation component or absolute positioning component of the observed row of rails 2 as a function of the continuous values of at least the absolute orientation components of the inertial unit and the continuous values of the relative orientation components of the observed row of rails with respect to the inertial unit. In practice, the algebraic sum of the instantaneous values of the absolute orientation components of the inertial unit and the simultaneous instantaneous values of the relative orientation components of each row of rails observed with respect to the inertial unit is simply performed (operation 46).
[0050] ψ R (t) is the value of the angle determined by the measuring device 28 in the horizontal plane between the longitudinal direction of the inertial measurement unit 34 and the direction of the observed row of rails 2 at the measurement time t, and ψ C (t) is the value of the yaw angle determined simultaneously by the inertial unit 34 at the same time point t, then the absolute orientation component ψ of the observed row of rails A(t) can be expressed as an algebraic sum.
Number
[0051] Similarly, θ R (t) is the instantaneous value of the angle determined by the measuring device in the vertical longitudinal plane between the longitudinal direction of the inertial measurement unit 34 and the direction of the rail 2 of the observed row, and θ C (t) is the instantaneous value of the pitch angle determined simultaneously by the inertial unit 34, the absolute orientation component θ of the row of rails A (t) can be expressed as an algebraic sum.
Number
[0052] Next, it is possible to construct one or more functions s→G(s) that connect at least some of the continuous surface abscissa values to the associated values among the continuous values of the absolute orientation component or absolute positioning component of the row of rails observed in space (operation 48).
[0053] Therefore, for one yaw component of the row of rails, the function s→G L (s) connects the value s(t) measured by the odometer associated with the rail of the observed row to the value ψ A (t) during all or at least some of the measurement times t. Similarly, the function s→G T (s) connects the value s(t) measured by the odometer associated with the rail of the observed row to the value θ A (t) during all or at least some of the measurement times t.
[0054] When this step is completed within the time domain, one or more functions in which time no longer appears as a variable are constructed s→G(s). Then, in order to construct the filtered function s→F(s), it is possible to apply to each such constructed function a linear bandpass filter or highpass filter, which is a spatial filter rather than a time filter (operation 50). The linear filter used is preferably a finite impulse response filter of any order N, preferably 2 or more, which results in the following linear combination. [Number] Here, b k represents the k-th coefficient of the filter transfer function, and s i represents the continuous values of the abscissa of the surface of the rail of the observed column for 1≤i≤n.
[0055] In practice, when aiming to observe the line shape parameters within the wavelength range defined by the standard, at least one bandpass filter in one of the following three bands: 3m to 25m (D1), 25m to 70m (D2), 70m to 150m (D3) is used, or the bandpass filter is implemented by the deflection calculation function (CF). In practice, operation 50 is performed in parallel for each of the desired wavelength ranges among those available, which is shown in Figure 5 by parallel sub-operations 510, 512, 514, 516.
[0056] Finally, for a series of current abscissa values l among the abscissa values of the surface, it is possible to estimate the integral I(l) over a given abscissa interval bounded by the reference abscissa value l 0 of the filtered function and the current abscissa value l (operation 52). [Number]
[0057] In practice, the integral I(l) is estimated by a Riemann sum or the trapezoidal method over a given interval with a step size of less than 25 cm, preferably less than 1 cm. For example, the Riemann sum is [Mathematics] where s 0 = l 0 and s P = l are the boundaries of the integral.
[0058] If necessary, this operation 52 is performed in parallel for each of the observed wavelength ranges, and thus parallel sub-operations 520, 522, 524, 526 are performed.
[0059] When the relative orientation component of rail 2 of the observed column with respect to the inertial unit 34 is the orientation angle in the horizontal plane and the absolute orientation component of the inertial unit is the yaw angle, the integral I(l) is the alignment parameter.
[0060] When the relative orientation component of rail 2 of the observed column with respect to the inertial unit 34 is the orientation angle with respect to the vertical longitudinal plane of the vehicle and the absolute orientation component of the inertial unit is the pitch angle, the integral I(l) is the longitudinal level parameter.
[0061] In practice, the calculations can be performed in real time by a computer mounted on the vehicle 12, a computer on the machine 14, or a remotely located computer.
[0062] In parallel with these computational operations, the signal generated by the measuring device 28 or the continuous values of the relative orientation components of the observed column of rail 2 with respect to the inertial unit 34 can be used to control the cylinder 24 for coupling the carrier vehicle to the machine for the purpose of minimizing the misalignment between the chassis 16 of the carrier vehicle 12 and the track 1.
[0063] When looking at the alignment with respect to the longitudinal direction in the horizontal plane, for example, the angle ψ observed for one of the columns of rail 2R Constructing a negative feedback loop aimed at minimizing, or more simply, minimizing the absolute value of the difference |y 1 -y 2 | observed in one column of Rail 2. When looking at both columns of the rail, it is possible to construct a feedback loop aimed at minimizing the sum of the absolute values of the deviations observed for each of the two columns of the rail. (|y 1 -y 2 | + |y 1 -y 2 |)
[0064] Similarly, when looking at the alignment with respect to the longitudinal direction in the horizontal plane, for example, constructing a negative feedback loop aimed at minimizing the angle θ R observed for one of the columns of the rail, or more simply, minimizing the absolute value of the difference |z 1 -z 2 | observed in one column of the rail. When looking at both columns of the rail, or aiming to minimize the sum of the absolute values of the deviations observed for each of the two columns of the rail, it is (|z 1 -z 2 | + |z 1 -z 2 |).
[0065] If necessary, the failure of the odometer 26 is detected by comparing the longitudinal acceleration value generated by the inertial unit 34 with the average acceleration value determined as a function of the signal generated by the odometer 26, and / or by comparing the angular velocity value about the vertical axis generated by the inertial unit 34 with the angular velocity value estimated from the signal generated by the odometer 26. When a failure is detected, a degradation mode calculation procedure is executed, and the successive curvilinear abscissa values of the vehicle 12 on each of the two columns of Rail 2 are determined as a function of at least the acceleration signal or the angular velocity signal generated by the inertial unit 34.
[0066] Of course, the examples shown and described above are provided for illustrative and non-limiting purposes only. It is expressly provided that it is possible to combine various illustrated embodiments to provide other embodiments.
[0067] As described in the description of the present invention, other principles for measuring the relative orientation of the inertial units with respect to each row of rails are also predictable.
[0068] It is also possible to equip the carrier vehicle with a single odometer, which enables direct measurement of the curvilinear abscissa of one of the rows of rails. Subsequently, the operation of determining the successive curvilinear abscissa values of the rails of the opposing row can be performed as a function of at least the signals generated by the odometer and the signals generated by the measuring device.
[0069] The process of determining the above-described track shape parameters can also be performed using a four-wheel carrier vehicle, or more generally, a railway vehicle that can be mounted on a plurality of wheel sets or bogies. Optionally, the chassis to which the inertial unit is attached can be connected to the wheels by one or more suspension stages, such as a primary suspension and / or a secondary suspension.
[0070] In these cases, the devices used to measure the relative orientation of each row of rails with respect to the inertial measurement unit preferably use measurement principles other than those described so far.
[0071] In one embodiment, the measuring device comprises at least one, preferably at least two, cameras for detecting one or more linear laser beams projected onto each of the rows of rails. For example, each camera is fixed within the reference coordinate system of the inertial unit and fixed to the chassis carrying the inertial unit, and is oriented to capture the position of the laser line projected onto the rails of the observed row. The measuring device determines the relative vertical and horizontal positions between the rails of the observed row and the camera by triangulation.
[0072] In another embodiment, the measuring device comprises at least one, preferably at least two, laser rangefinders for scanning the rows of rails of the track and is arranged within the reference coordinate system of the inertial unit. According to the principle of laser telemetry, the distance is given by measuring the delay between the emission of a pulse and the detection of the reflected pulse. The projected laser beam is directed by a rotating mirror that scans a plane of space that can cover both rows of rails and triangulates each row of rails to derive measurements of the lateral distance and the longitudinal distance. By means of two laser rangefinders arranged at a distance from each other in the longitudinal direction of the vehicle, it is possible to obtain the eight required dimensions, namely four lateral distances and four longitudinal distances.
[0073] In another variant, the measuring device comprises at least one time-of-flight (ToF) camera arranged within the reference coordinate system of the inertial unit, enabling a 3D scene to be seen within its field of view. Since the field of view of this type of camera is relatively narrow, it is advantageous to use one such camera per row of rails.
Claims
1. A method for determining at least one shape parameter of a railway track (1) having two rows of rails (2), comprising: - A vehicle (10) equipped with an inertial unit (34), a device (28) for measuring at least one relative orientation component of at least one of the two rows of rails with respect to the inertial unit, and one or more odometers (26) is made to run on the track (1); - The continuous values of at least one absolute orientation component of the inertial unit (34) in a stationary reference coordinate system are determined as a function of at least the signals generated by the inertial unit (34); - For at least one observed row of rails (2) of the two rows of rails (2), preferably for each of the two rows of rails (2) regarded as the observed row of rails, i) The continuous values of the curvilinear abscissa of the vehicle on the observed row of rails (2) are determined as a function of at least the signals generated by the odometer (26); ii) The continuous values of at least one relative orientation component of the observed row of rails with respect to the inertial unit (34) are determined as a function of at least the signals generated by the measuring device (28); iii) The continuous values of at least one absolute orientation component or absolute positioning component of the observed row of rails (2) are calculated as a function of the continuous values of at least the absolute orientation components of the inertial unit (34) and the continuous values of the relative orientation components of the observed row of rails (2) with respect to the inertial unit (34); iv) A function s→G(s) that connects at least some of the continuous curvilinear abscissa values to the accompanying values among the continuous values of the absolute orientation components or absolute positioning components of the observed row of rails in space is constructed; v) A high-pass linear filter or a band-pass linear filter is applied to the function s→G(s) to construct a filtered function s→F(s). vi) For a series of current surface abscissa values l among the surface abscissa values, the integral I(l) is estimated over a given surface abscissa interval bounded by the reference surface abscissa value l of the filtered function and the current surface abscissa value l ０ and the current surface abscissa value l A method, characterized in that. 【Number 1】
2. The method according to claim 1, characterized in that the linear filter is preferably a band-pass filter in one of the following three bands: 3 m to 25 m, 25 m to 70 m, 70 m to 150 m, or an arrow calculation function.
3. The method according to claim 1 or 2, wherein the integral I(l) is estimated by a Riemann sum or a trapezoidal method over the given interval with a step size of less than 25 cm, preferably less than 1 cm.
4. The operation of calculating the continuous values of at least one absolute orientation component or absolute positioning component of the rail (2) of the observed column, at consecutive time points, is composed of the instantaneous value of the absolute orientation component of the inertial unit and the algebraic sum of the simultaneous instantaneous values of the respective relative orientation components of the rail of the observed column with respect to the inertial unit. The method according to any one of claims 1 to 3.
5. The method according to any one of claims 1 to 4, wherein the relative orientation component of the rail (2) of the observed column with respect to the inertial unit (34) is an orientation angle in the horizontal plane, the absolute orientation component of the inertial unit is a yaw angle, and the integral I(l) is an alignment parameter.
6. The method according to any one of claims 1 to 5, wherein the relative orientation component of the rail (2) of the observed column with respect to the inertial unit (34) is an orientation angle in the vertical plane (V) of the vehicle (12), the absolute orientation component of the inertial unit is a pitch angle, and the integral I(l) is a longitudinal level parameter.
7. For each rail (2) of the observed column, the measuring device generates at least two simultaneous signals for measuring the lateral distance between two reference points (30) on the vehicle (12) and the rail (2) of the observed column, and the two reference points (30) are separated from each other by a distance (A) greater than 250 mm, preferably greater than 500 mm. The method according to any one of claims 1 to 6.
8. For each rail (2) of the observed column, the measuring device generates at least two simultaneous signals for measuring the lateral distance between two reference points (32) of the vehicle (12) and the rail (2) of the observed column, and the two reference points (32) are separated from each other by a distance (B) greater than 250 mm, preferably greater than 500 mm. The method according to any one of claims 1 to 7.
9. At least one actuator (24) for correcting the alignment of the vehicle (12) on the line (1) is controlled as a function of the signal generated by the measuring device (28) and a predetermined value to reduce the drift between them, or as a function of the continuous values of the relative orientation components of the rails (2) of the observed train and a predetermined value of the relative orientation components of the rails (2) of the observed train, in order to reduce the drift between them. The method according to any one of claims 1 to 8, characterized in that it is controlled as a function of the signal generated by the measuring device (28), or as a function of the continuous values of the relative orientation components of the rails (2) of the observed train with respect to the inertial unit (34).
10. The operation of determining the continuous curvilinear abscissa values of the vehicle (12) on the rails (2) of the observed train is carried out as a function of the signal generated by the odometer associated with the rails (2) of the observed train, selected from at least the odometers (26). The method according to any one of claims 1 to 9, characterized in that it is carried out as a function of the signal generated by the odometer associated with the rails (2) of the observed train, selected from at least the odometers (26).
11. The operation of determining the continuous curvilinear abscissa values of the vehicle on the rails (2) of the observed train is carried out as a function of the signal generated by the odometer not associated with the rails (2) of the observed train, selected from at least the odometers (26), and the signal generated by the measuring device (28). The method according to any one of claims 1 to 10, characterized in that it is carried out as a function of the signal generated by the odometer not associated with the rails (2) of the observed train, selected from at least the odometers (26), and the signal generated by the measuring device (28).
12. The failure of the odometer (26) is detected by comparing the longitudinal acceleration value generated by the inertial unit (34) with the average acceleration value determined as a function of the signal generated by the odometer (26), and / or by comparing the angular velocity value about the vertical axis generated by the inertial unit (34) with the angular velocity value estimated from the signal generated by the odometer (26). The method according to any one of claims 1 to 11, characterized in that it is detected by comparing the longitudinal acceleration value generated by the inertial unit (34) with the average acceleration value determined as a function of the signal generated by the odometer (26), and / or by comparing the angular velocity value about the vertical axis generated by the inertial unit (34) with the angular velocity value estimated from the signal generated by the odometer (26).
13. When a failure is detected, a safety procedure is executed, and the continuous curvilinear abscissa values of the vehicle (12) on each of the two rails (2) are determined as a function of at least the acceleration signal or the angular velocity signal generated by the inertial unit (34). The method according to claim 12, characterized in that it is determined as a function of at least the acceleration signal or the angular velocity signal generated by the inertial unit (34).
14. A system for implementing the method according to any one of the preceding claims, comprising a vehicle capable of traveling on a railway line (1) having two parallel rows of rails (2), said vehicle (12) having an inertial unit (34) having at least three gyroscopes and three accelerometers, one device (28) for measuring the relative orientation of each of said two rows of rails (2) with respect to said inertial unit (34), and one or more odometers (26), said system calculating continuous values of at least one absolute orientation component or absolute positioning component of the rail (2) of the observed row among said two rows of rails, constructing a function s→G(s), applying a linear filter, constructing a filtered function s→F(s), and further comprising computing means programmed to execute an operation for estimating an integral I(l).
15. The measuring device (28) associated with each of said two rows of rails (2) comprises at least two sensors for measuring the lateral distance (30) between two reference points on the vehicle and the associated row of rails, said two reference points being separated from each other by a distance (A) greater than 250 mm, preferably greater than 500 mm. The system according to claim 14, characterized in that
16. The measuring device (28) associated with each of said two rows of rails (2) comprises at least two sensors for measuring the longitudinal distance (32) between two reference points on the vehicle and the associated row of rails (2), said two reference points being separated from each other by a distance (B) greater than 250 mm, preferably greater than 500 mm. The system according to claim 14 or 15, characterized in that
17. The measuring device (28) comprises at least one, preferably at least two, cameras for detecting one or more linear laser beams projected onto each of the rails of the row. The system according to any one of claims 14 to 16, characterized in that
18. The measuring device (28) comprises at least one, preferably at least two, laser rangefinders for scanning the rails of the row of the track. The system according to any one of claims 14 to 17, characterized in that
19. The system according to any one of claims 14 to 18, characterized in that the vehicle (12) is a two-wheeled transporter (18), driven by a machine (14) and connected to the machine via at least three links (22, 24) for controlling the attitude and alignment of the transporter (12) as a function of relative orientation components.
20. The system according to any one of claims 14 to 18, characterized in that the vehicle (12) is a transporter having at least four wheels.