System for determining forward speed of at least one vehicle

Abstract

A system for determining a forward speed of at least one vehicle is described, comprising control means each associated with at least one axle and communication means for transmitting signals or values ​​between the control means. At successive measurement instants in time, each control means generates a corresponding slip signal for a respective at least one axle. At a shared instant, each control means transmits a respective slip signal and, in a non-slip condition, transmits to the other control means a value of a quantity related to the rotation of the respective axle or its own estimated forward speed of the vehicle. When all slip signals indicate a slip condition, one of said control means controls a first braking means associated with one of the axles in order to reduce the braking force applied to said axle.

Description

[Technical field]

[0001] The present invention relates generally to the field of vehicles. In particular, the present invention relates to a system for determining the forward speed of at least one vehicle. [Background technology]

[0002] Slippage (also known as slip or slide) is understood to be a condition in which there is a difference between the rotational speed of the axles or wheels of a vehicle and the speed at which the vehicle itself is moving. This difference is usually defined as the slippage speed.

[0003] For example, with reference to the rail vehicle sector, slip speed can be calculated by the following formula:

number

[0004] More modern rail vehicles are fitted with electronic systems including subsystems for controlling wheel slippage, adapted to intervene both when the vehicle is in the traction phase and when the vehicle is in the braking phase. This type of subsystem is known as an anti-skid system or anti-sliding system, also known as a WSP (Wheel Skid Prevention) system.

[0005] A system for controlling wheel adhesion in an anti-skid function according to the prior art is shown diagrammatically in Figure 1 and refers to a vehicle with n controlled axles A1, A2, ..., An, each axle A1, A2, ..., An comprising a respective shaft S1, S2, ..., Sn and a respective pair of wheels W1, W2, ..., Wn connected thereto for co-rotation. In FIG. 1, typically only one wheel on each axle is shown.

[0006] 1 comprises an electronic control unit ECU, typically based on a microprocessor architecture, receiving tachometric signals relating to the angular velocity of each axle A1, A2, ..., An from sensors SS1, SS2, ..., SSn associated with each of these axles. The electronic unit ECU is also connected to torque control devices TC1, TC2, ..., TCn associated with each of the associated axles A1, A2, ..., An.

[0007] The electronic unit ECU is configured to adjust the torque applied to each axle according to a predetermined algorithm. When torque is applied during a traction or braking phase in a reduced adhesion situation, it may cause incipient slippage of the wheels of one or more axles. The torque is adjusted in such a way as to completely prevent axle jamming with the aim of restoring adhesion, and possibly even in such a way as to bring each axle into a controlled slippage situation for the entire duration of the reduced adhesion condition.

[0008] Instantaneous vehicle speed V RV It is clear that knowledge of (t) is the basis for accurate control of slip. One known method for accurately tracking the forward speed of a rail vehicle involves the maintenance of an idle axle, i.e. an axle that is not subjected to traction or braking torque. This is because the speed measurement is inversely proportional to the actual speed V of the rail vehicle in question. real This solution is particularly effective when the adhesion between the wheels and the track is particularly low. In this case, when towing or braking, all the wheels may enter a slipping state and therefore cannot provide accurate information about the actual speed of the vehicle. The idle axles, which are not subjected to traction or braking torques, can continue to accurately track the speed of the vehicle.

[0009] Obviously, use of an "idle" axle results in a temporary loss of traction and braking capabilities of the vehicle. For example, Figure 2a shows an example configuration with two independent cars, and Figure 2b shows an example configuration with two cars restrained by a Jacobs bogie. The use of an idle axle reduces the tractive and braking capacity by 12.5% ​​in the former case and 16.7% in the latter case.

[0010] Where there are multiple electronic unit ECUs, each arranged to adjust the torque applied to a respective group of axles, for example with a first electronic unit ECU configured to control the axles of a first vehicle in the train and a second electronic unit ECU configured to control the axles of a second vehicle in the train, each electronic unit ECU may disadvantageously place the axles controlled by it into an "idle" axle condition.

[0011] Modern rail vehicle construction, especially in subways, tends to be very restrictive, for example consisting of two cars, in which case the use of multiple "idle" axles can result in a significant loss of traction and braking capacity of the vehicle or train.

[0012] Referring again to Figures 2a and 2b, for example, the use of two idle axles reduces tractive and braking capacity by 25% in the former case and by 33.4% in the latter case. Naturally, this limitation severely impairs the towing and braking capabilities of the vehicle or train of vehicles in skid conditions.

[0013] The disadvantages discussed above with respect to the rail vehicle sector apply equally to other sectors of vehicles, such as road vehicles, where an axle may end up in an "idle" axle condition in the event of a slippage. Summary of the Invention [Problem to be solved by the invention]

[0014] It is therefore one object of the present invention to provide a solution for minimizing the loss of traction and braking capability of at least one vehicle or train of vehicles, even in slippage conditions, while maintaining the ability to reliably determine the forward speed of the at least one vehicle or train of vehicles. [Means for solving the problem]

[0015] These and other objects and advantages are achieved according to one aspect of the invention by a system for determining the forward speed of at least one vehicle having the features defined in claim 1. The above-mentioned objects and advantages and other objects and advantages are achieved according to a further aspect of the invention by a vehicle having the features defined in claim 14. Preferred embodiments of the invention are defined in the dependent claims, the content of which is to be understood as an integral part of this description. [Brief description of the drawings]

[0016] The functional and structural features of some preferred embodiments of the system for determining the forward speed of at least one vehicle and the vehicle according to the present invention will now be described with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 illustrates an exemplary wheel adhesion control system with anti-skid function according to the prior art. [Figure 2a] FIG. 2a shows an example of a convoy configuration with two separate vehicles. [Figure 2b] FIG. 2b shows an example of a convoy configuration with two cars joined by a Jacobs bogie. [Diagram 3] FIG. 3 illustrates an embodiment of a system for determining a forward speed of at least one vehicle. [Figure 4] FIG. 4 is a diagram illustrating a further embodiment of a system for determining a forward speed of at least one vehicle, wherein a first portion of a plurality of control means is mounted on the first vehicle and a second portion of the plurality of control means is mounted on the second vehicle. [Diagram 5]FIG. 5 illustrates yet another embodiment of a system for determining the forward speed of at least one vehicle, where all control means are located on a single vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Before describing the embodiments of the present invention in detail, it should be made clear that the present invention is not limited in its application to the design details and configuration of components set forth in the following description or illustrated in the drawings. The present invention can envision other embodiments and can actually be implemented or constructed in different ways. It is also to be understood that the phraseology and terminology are for descriptive purposes and should not be construed as limiting. The use of "include" and "comprise" and variations thereof should be understood to encompass the elements described below and their equivalents, as well as additional elements and their equivalents.

[0018] FIG. 3 illustrates an exemplary embodiment of a system 300 for determining a forward speed of at least one vehicle. In a first embodiment, the system 300 for determining the forward speed of at least one vehicle comprises a number of control means 302, 302', 302'', 302''', each control means 302, 302', 302'', 302''', associated with at least one axle A1, A2, A3, A4, A5, A6, A7, A8 of a bogie B1, B2, B3, B4 of the vehicle. Preferably, as shown by way of example in FIG. 3, the first control means may control all axles of a bogie of the vehicle or may control four axles of two bogies of the vehicle. Also, in a further non-limiting example shown in FIG. 4, the first control means may control all axles of a first bogie of the vehicle and the second control means may control all axles of a second bogie or may control two axles of the second bogie. It is clear that the number of axles or bogies in additional vehicle types may also differ from those mentioned for illustrative purposes.

[0019] The control means may preferably be or include, for example, at least one controller, processor, microcontroller, microprocessor, control unit, control module, FPGA, PLC or the like.

[0020] The system 300 for determining the forward speed of at least one vehicle further comprises communication means 304 configured to enable the transmission of signals or values ​​between said control means. Preferably, the successive measurement instants in time may be defined according to a predefined measurement period.

[0021] Each control means 302, 302', 302'', 302''' is configured to generate a corresponding slip signal indicative of a respective slip or non-slip condition of the at least one axle with which it is associated.

[0022] Between said measurement instants there is at least one shared instant during which each control means 302, 302', 302'', 302''' is configured to transmit to the other control means a respective slip signal, at least in the absence of slip of the respective axle, the value of a quantity related to the rotation of the respective axle, or an own estimated forward speed of the vehicle determined as a function of the value of the quantity related to the rotation of the respective axle.

[0023] Preferably, for example, the value of the quantity related to the rotation of the respective axle may be the angular velocity of said axle or the rotation frequency of said axle, or any other quantity related to the rotation of said axle.

[0024] A given one of the plurality of control means 302, 302', 302'', 302''' is configured to control a first braking means associated with one of said axles to reduce the braking force applied to said axle when all of the slippage signals indicate a slippage condition for the respective axle, in order to bring said axle into a non-slip condition. In one example, the braking force may be reduced to a point that places the axle in an "idle" axle condition.

[0025] In other words, the braking force applied to an axle needs to be reduced only when all axles of at least one vehicle are in a slipping phase and cannot give a reliable indication of the rotation of said axles, so that said axles can rotate and give a reliable indication from which the forward speed of the vehicles can be derived.It is no longer necessary to keep the axles in a non-braked state, since it is sufficient that at least one axle of at least one vehicle is in a non-slipping phase or has returned to a non-slipping state.

[0026] Each control means 302, 302', 302'', 302''', upon detecting a slippage condition of at least one respective axle with which it is associated, is configured to determine its own estimated forward speed of the vehicle based on at least one value of said quantity related to the rotation of the respective axle transmitted by at least one control means with which the associated axle is in a non-slip state, or to determine an estimated forward speed of the vehicle based on an estimated forward speed of the vehicle transmitted by another control means with which the associated axle is in a non-slip state.

[0027] The axle for which a given control means reduces braking force may preferably be the axle associated with said given control means. The axle for which the given control means reduces braking force may preferably be associated with another axle of the control means. The predetermined control means may preferably be configured to continue reducing the braking force applied to the at least one axle at least until a next measurement instant occurs.

[0028] The communication means 304 may be preferably configured to enable the transmission of signals or values ​​between the plurality of control means 302, 302', 302'', 302''' according to a predefined safety protocol. The predefined safety protocol is preferably a black channel protocol.

[0029] Each control means 302, 302', 302'', 302''' may preferably be a control means configured to manage the braking of at least one associated axle, or a control means of for example an electronic unit of a WSP system. In other words, a control means already responsible for the braking control of one or more axles may further be used as a control means for determining the forward speed of at least one vehicle.

[0030] Each control means 302, 302', 302'', 302''' may preferably be configured as follows. - upon receiving the values ​​of the quantities related to the rotation of the respective axles from the at least one other control means, comparing the values ​​of the quantities related to the rotation of the respective axles with the values ​​of the quantities related to the rotation of the respective axles transmitted by the at least one other control means; - configured to generate an alarm signal if the comparison indicates that the value of the quantity related to the rotation of the associated respective axle differs from the value of the quantity related to the rotation of the transmitted respective axle by at least a predetermined threshold value. or - upon receiving the estimated forward speed of the vehicle determined by the at least one other control means, comparing the value of the vehicle's own estimated forward speed with the value of the vehicle's estimated forward speed transmitted by the at least one other control means, - configured to generate an alarm signal if the comparison indicates that the value of the estimated forward speed of the vehicle differs from the value of the estimated forward speed of the vehicle transmitted by the at least one other control means by at least a predetermined threshold value.

[0031] The alarm signal may be provided, for example, to an engineer or driver's display in the vehicle, to an additional on-board vehicle control unit, or to a remote control centre via radio or wireless communication means.

[0032] Each control means 302, 302', 302'', 302''' may preferably be configured as follows. - configured to determine, upon receiving a value of the quantity related to the rotation of the respective axle from the at least one other control means, that the effective value of the quantity related to the rotation of the respective axle corresponds to the greater of the value of the quantity related to the rotation of the associated respective axle and the value of the quantity related to the rotation of the respective axle transmitted by the at least one other control means. or - configured to determine, when receiving the estimated forward speed of the vehicle determined by the at least one other control means, that the effective value of the forward speed of the vehicle corresponds to the greater of the value of the vehicle's own estimated forward speed and the value of the estimated forward speed of the vehicle transmitted by the at least one other control means.

[0033] The above measures may be applied when the system for determining the forward speed of the at least one vehicle determines that the at least one vehicle is in a braking phase. The maximum value may preferably be selected by excluding values ​​that are outside at least one standard deviation (1σ) of the mean, or at least two standard deviations (2σ) of the mean, or at least three standard deviations (3σ) of the mean.

[0034] Each control means 302, 302', 302'', 302''' may preferably be configured as follows. - configured to determine, upon receiving a value of the quantity related to the rotation of the respective axle from the at least one other control means, that the effective value of the quantity related to the rotation of the respective axle corresponds to the smaller of the value of the quantity related to the rotation of the associated respective axle and the value of the quantity related to the rotation of the respective axle transmitted by the at least one other control means. or - configured to determine, when receiving an estimated forward speed of the vehicle determined by the at least one other control means, that the effective value of the forward speed of the vehicle corresponds to the smaller of the value of the vehicle's own estimated forward speed and the value of the estimated forward speed of the vehicle transmitted by the at least one other control means.

[0035] For example, the above measures may be applied when a system for determining the forward speed of the at least one vehicle determines that the at least one vehicle is in an acceleration phase.

[0036] The minimum value may preferably be selected by excluding values ​​that are outside at least one standard deviation (1σ) of the mean, or at least two standard deviations (2σ) of the mean, or at least three standard deviations (3σ) of the mean.

[0037] In yet another embodiment, each control means 302, 302', 302'', 302''' may preferably be configured as follows. - configured to determine, when receiving values ​​of the quantities related to the rotation of the respective axles from the at least one other control means, that the effective value of the quantities related to the rotation of the respective axles corresponds to an average value of the values ​​of the quantities related to the rotation of the associated respective axles and of the values ​​of the quantities related to the rotation of the respective axles transmitted by the at least one other control means. or - configured to determine, when receiving an estimated forward speed of the vehicle determined by the at least one other control means, that the effective value of the forward speed of the vehicle corresponds to an average value of the value of the vehicle's own estimated forward speed and of the value of the estimated forward speed of the vehicle transmitted by the at least one other control means.

[0038] The mean value may preferably be selected by excluding values ​​that are outside at least one standard deviation (1σ) of the mean, or at least two standard deviations (2σ) of the mean, or at least three standard deviations (3σ) of the mean.

[0039] As shown in FIG. 4, preferably, the vehicles include at least a first vehicle V1 and a second vehicle V2 connected to the first vehicle, and a first portion 302, 302' of the plurality of control means may be installed in the first vehicle, and a second portion 302'', 302''' of the plurality of control means may be installed in the second vehicle. Alternatively, as shown in FIG. 5, preferably all control means 302, 302', 302'', 302''' may be located in one vehicle.

[0040] Preferably, according to any of the above-mentioned embodiments, the at least one vehicle 300 for which the system for determining the forward speed of the at least one vehicle determines the forward speed of may be at least one rail vehicle.

[0041] In a further aspect, the present invention relates to a vehicle comprising a plurality of axles and a system 300 for determining a forward speed of at least one vehicle according to any of the previous embodiments. Preferably, such vehicle is at least one rail car or rail convoy. In further exemplary embodiments, such a vehicle may preferably be a vehicle from the general vehicle sector, for example the automotive sector, such as a wheeled vehicle or a wheeled train.

[0042] The advantage achieved is that it provides a solution that minimizes the loss of traction and braking capacity of a vehicle or convoy while maintaining the ability to reliably determine the forward speed of at least one vehicle or convoy. Such a solution does not utilize one or more idle axles, which would reduce the traction and braking capabilities of the vehicle (or train) in all adhesion conditions (i.e. even when adhesion is not degraded), but instead uses a "dynamic" idle axle, i.e. an axle that is de-braked only when necessary when all axles in the train are in a slipping condition. Moreover, thanks to the communication means 304, such an idle axle is explicitly selected (and therefore there is only one) at the train level.

[0043] The above description, which for example refers to the rail vehicle sector, may also find similar application in other sectors, such as the general sector of vehicles, wheeled vehicles or trains, where in the event of slippage the axles may find themselves in a so-called "idle" axle condition.

[0044] Although various aspects and embodiments of the system and vehicle for determining the forward speed of at least one vehicle according to the invention have been described, it is understood that each embodiment can be combined with other embodiments. Moreover, the invention is not limited to the described embodiments, but can be modified within the scope defined by the appended claims.

Claims

1. A system (300) for determining a forward speed of at least one vehicle (V1, V2), comprising: a plurality of control means (302, 302', 302'', 302'''); and communication means (304) configured to enable the transmission of signals or values ​​between said plurality of control means (302, 302', 302'', 302'''), each said control means being associated with at least one axle (A1, A2, A3, A4, A5, A6, A7, A8) of a bogie (B1, B2, B3, B4) of said vehicle; at successive measurement instants in time, each of said control means (302, 302', 302'', 302''') is configured to generate a corresponding slippage signal indicative of a respective slippage or non-slippage state of the at least one axle associated therewith; Between said measurement instants there is at least one shared instant in which each of said control means is configured to transmit to the other of said control means a respective said slippage signal and, at least when each of said axles is in said non-slip state, a value of a quantity related to the rotation of said respective axle or an estimated forward speed of said vehicle itself determined as a function of the value of a quantity related to the rotation of said respective axle; a predetermined control means (302) of the plurality of control means (302, 302', 302'', 302''') is configured to control a first braking means associated with one of the axles to reduce a braking force applied to the axle to bring the axle into the non-slip state when all of the slip signals indicate the slip state of the respective axle; each of said control means (302, 302', 302'', 302''') is configured, upon detecting a slippage state of at least one respective axle associated therewith, to determine said estimated forward speed of said vehicle itself based on at least one value of said quantity related to said rotation of said respective axle transmitted by at least one of said control means whose associated axle is in said non-slip state, or to determine said estimated forward speed of said vehicle itself based on said estimated forward speed of said vehicle transmitted by another of said control means whose associated axle is in said non-slip state; A system (300) for determining the forward speed of at least one vehicle (V1, V2), characterized in that:

2. 2. The system (300) for determining the forward speed of at least one vehicle according to claim 1, wherein the axle for which the predetermined control means (302) reduces braking force is the axle (A1, A2) associated with the predetermined control means.

3. 2. The system (300) for determining the forward speed of at least one vehicle according to claim 1, wherein the axle for which the given control means (302) reduces braking force is the axle (A3, A4, A5, A6, A7, A8) associated with another of the control means (302', 302'', 302''').

4. 2. The system (300) for determining the forward speed of at least one vehicle according to claim 1, wherein the predetermined control means (302) is configured to continue reducing the braking force applied to the at least one axle at least until a next measurement instant occurs.

5. 2. The system (300) for determining the forward speed of at least one vehicle according to claim 1, wherein the communication means (304) is configured to enable transmission of the signals or values ​​between the plurality of control means (302, 302', 302'', 302''') in accordance with a predetermined safety protocol.

6. 6. The system (300) for determining the forward speed of at least one vehicle according to claim 5, wherein said predetermined safety protocol is a Black channel protocol.

7. 2. The system (300) for determining the forward speed of at least one vehicle according to claim 1, wherein each of said control means (302, 302', 302", 302"") is a control means configured to manage braking of said at least one associated axle.

8. Each of said control means (302, 302', 302'', 302''') - upon receiving a value of said quantity related to said rotation of each of said axles from at least one other of said control means, comparing said value of said quantity related to said rotation of each of said axles with the value of said quantity related to said rotation of each of said axles transmitted by said at least one other of said control means; - configured to generate an alarm signal if the comparison indicates that the value of the quantity related to the rotation of each of the associated axles differs from the transmitted value of the quantity related to the rotation of each of the axles by at least a predetermined threshold value; or - upon receiving the estimated forward speed of the vehicle determined by the at least one other control means, comparing the value of the vehicle's own estimated forward speed with the value of the vehicle's estimated forward speed transmitted by the at least one other control means, - configured to generate a warning signal if the comparison indicates that the value of the estimated forward speed of the vehicle itself differs from the value of the estimated forward speed of the vehicle transmitted by the at least one other of the control means by at least a predetermined threshold value; The system (300) for determining the forward speed of at least one vehicle according to claim 1.

9. Each of said control means (302, 302', 302'', 302''') configured to determine, upon receiving the value of the quantity related to the rotation of each of the axles from said at least one other control means, that the effective value of said quantity related to the rotation of each of the axles corresponds to the greater of said value of said quantity related to the rotation of each of the axles with which it is associated and the value of said quantity related to the rotation of each of the axles transmitted by said at least one other control means; or configured to determine, when receiving the estimated forward speed of the vehicle determined by the at least one other said control means, that the effective value of the forward speed of the vehicle corresponds to the greater of the value of the estimated forward speed of the vehicle itself and the value of the estimated forward speed of the vehicle transmitted by the at least one other said control means, The system (300) for determining the forward speed of at least one vehicle according to claim 1.

10. Each of said control means (302, 302', 302'', 302''') configured to determine, upon receiving the value of the quantity related to the rotation of each of the axles from said at least one other control means, that the effective value of said quantity related to the rotation of each of the axles corresponds to the smaller of the value of said quantity related to the rotation of the associated respective axle and the value of said quantity related to the rotation of each of the axles transmitted by said at least one other control means; or configured to determine, when receiving the estimated forward speed of the vehicle determined by said at least one other said control means, that the effective value of said forward speed of said vehicle corresponds to the smaller of the value of said estimated forward speed of said vehicle itself and the value of said estimated forward speed of said vehicle transmitted by said at least one other said control means, The system (300) for determining the forward speed of at least one vehicle according to claim 1.

11. Each of said control means (302, 302', 302'', 302''') configured to determine, upon receiving the values ​​of the quantities related to the rotation of each of the axles from said at least one other control means, that the effective value of said quantities related to the rotation of each of the axles corresponds to the average value of the values ​​of the quantities related to the rotation of each of the associated axles and of the values ​​of the quantities related to the rotation of each of the axles sent by said at least one other control means; or configured to determine, when receiving the estimated forward speed of the vehicle determined by said at least one other said control means, that the effective value of said forward speed of said vehicle corresponds to the average value of said estimated forward speed of said vehicle itself and of the value of said estimated forward speed of said vehicle transmitted by said at least one other said control means, The system (300) for determining the forward speed of at least one vehicle according to claim 1.

12. 2. The system (300) for determining the forward speed of at least one vehicle according to claim 1, wherein the vehicles include at least a first vehicle (V1) and a second vehicle (V2) connected to the first vehicle, a first portion of the plurality of control means (302, 302') being installed on the first vehicle, and a second portion of the plurality of control means (302'', 302''') being installed on the second vehicle.

13. The system (300) for determining the forward speed of at least one vehicle according to claim 1, wherein all control means (302, 302', 302'', 302''') are installed on a single vehicle.

14. A vehicle comprising a plurality of axles and a system (300) for determining at least one vehicle forward speed according to claim 1.

15. 15. The vehicle of claim 14, wherein the vehicle is at least one rail car or rail train.

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