EP1451545A1

EP1451545A1 - System for automatically determining a public transport vehicle emergency braking characteristics, in particular of a railway vehicle

Info

Publication number: EP1451545A1
Application number: EP02796895A
Authority: EP
Inventors: Julien Leblanc; Bruno Perrin; Vincent Poupinet
Original assignee: Regie Autonome des Transports Parisiens
Current assignee: Regie Autonome des Transports Parisiens
Priority date: 2001-12-07
Filing date: 2002-12-03
Publication date: 2004-09-01
Also published as: AU2002361365A1; MXPA04005448A; US20050065677A1; CN1330951C; FR2833350B1; FR2833350A1; CA2468974A1; WO2003048710A1; US7412312B2; CA2468974C; CN1613005A; BR0215103A

Abstract

The invention concerns a system for automatically determining a public transport vehicle emergency braking characteristics, in particular of a railway vehicle, comprising means (1) for measuring the vehicle speed, means (2) for measuring the distance travelled by it, and means (3) for triggering an emergency braking of the vehicle to actuate its braking means (4). The invention is characterized in that it comprises means for detecting (5) the activation of the means (3) triggering the emergency braking and means for detecting (5) when the vehicle stops, adapted to activate/deactivate the operation of means (9) acquiring data concerning the speed and the distance travelled by the vehicle for a time interval running between the activation of the emergency triggering means and the moment the vehicle stops, and means (9) for analyzing said data to deliver at least a information concerning the distance travelled by the vehicle during said time interval.

Description

System for automatically determining the emergency braking characteristics of a public transport vehicle, particularly a rail vehicle.

The present invention relates to a system for automatically determining the emergency braking characteristics of a public transport vehicle, in particular a rail vehicle. We know that in this area of activity, passenger safety is a constant concern.

In particular, these transport vehicles must have predetermined emergency braking characteristics.

Manufacturers and users of this type of equipment are therefore required to periodically check that these vehicles and in particular their braking systems are working properly.

This is achieved, in the state of the art, by carrying out tests or tests on the vehicles, which are then brought to move on test bases whose characteristics, in particular of terrain configuration, are known.

A test base is then marked by two remarkable physical markers which delimit a predetermined maximum stopping distance which the vehicle must respect when braking. This maximum distance is also called the "acceptability threshold". The vehicle is then brought to move in this test base at its nominal speed. Two operators are on board this vehicle, one driving the vehicle and the other monitoring the passage of the vehicle in front of the first marker, to warn the driver so that when the vehicle passes in front of this marker, this driver triggers the braking of vehicle emergency by activating corresponding triggering means in order to actuate the braking means thereof.

The braking is then maintained until the vehicle comes to a complete stop.

A mechanical type accelerometer can be taken on board the vehicle in order to deliver information relating to the instantaneous deceleration of the vehicle during this phase. Once the vehicle has stopped, the operator checks the place where the vehicle stopped and in particular, its relative position with respect to the second marker.

If the vehicle has stopped after the second marker, that is to say downstream of it, it is considered that this vehicle has a braking malfunction.

On the other hand, if the vehicle has stopped before the second marker, that is to say upstream of it, the operator measures the distance between the vehicle and this second marker, to deduce the distance from it. vehicle stopped since the distance between the two marks is known. Various operations are then carried out manually by this operator, who may have to make corrections to the calculated stopping distance to take account in particular of the configuration of the terrain of the test base.

It is also required to calculate a deceleration time of the vehicle.

The calculated and possibly corrected stopping distance is also compared by the operator to a predetermined acceptability threshold for the vehicle concerned and the test base concerned, in order to determine whether or not the vehicle has braking malfunction. The operator also analyzes the shape of the deceleration curve and in particular the brake rise and release times.

This different information and the results of the test, as well as environmental information, such as for example those relating to the weather conditions at the time of the test, the name of the operator, the date, the vehicle number , etc., are then recorded in a report.

It is understood, however, that this has a number of drawbacks.

Indeed, these procedures are relatively cumbersome and tedious to implement and require significant logistics. In addition, it is necessary to embark on board a vehicle, an accelerometer and to ensure the implementation thereof.

The stopping distance is measured and calculated manually by an operator. Finally, the risks of errors linked to the implementation of such methods are not negligible due to the fact that the actuation of the means for triggering the emergency braking is carried out by the driver of the vehicle on the order of the operator who must himself visually estimate the passage of the vehicle in front of the first marker.

All this is reflected in the fact that these methods pose problems of reproducibility and traceability of the tests.

The object of the invention is therefore to solve these problems. To this end, the subject of the invention is a system for automatically determining the emergency braking characteristics of a public transport vehicle, in particular a rail vehicle, comprising means for measuring the speed of the vehicle, means for measurement of the distance traveled by the latter, and of means for triggering an emergency braking of the vehicle for actuating the braking means of the latter, characterized in that it comprises means for detecting activation means for initiating the emergency braking of the vehicle and means for detecting the stopping of the vehicle, adapted to activate / deactivate the operation of means for acquiring information of speed and distance traveled by the vehicle during the period of time elapsing between the activation of the means for initiating the emergency braking and the stopping of the vehicle, and means for analyzing this information to deliver at least distance information pa used by the vehicle during this period.

According to other characteristics:

the analysis means are adapted to further deliver information on instantaneous deceleration of the vehicle during this period of time;

- The analysis means are adapted to further deliver response time information from the vehicle braking means, following the activation of the emergency braking triggering means;

- the analysis means are adapted to deliver the or each braking characteristic in real time;

- the analysis means are adapted to deliver the or each characteristic in deferred time;

the analysis means include means for correcting the information on the distance traveled by the vehicle determined from the information messages delivered by the acquisition means, to take account of the reaction time of these acquisition means;

- The analysis means include means for smoothing the deceleration information of the vehicle; the smoothing means include filtering means with a sliding time window;

the analysis means comprise means for calculating the response time information of the braking means according to the relation te = tr + tt / 2 where you represent the response time, tr represents the time elapsed between the start of the braking until the vehicle deceleration reaches 10% of the deceleration value in steady state and tt represents the time elapsed from the start of braking until the vehicle deceleration reaches 90% of the deceleration value in established regime;

the analysis means comprise means for comparing the or each braking characteristic delivered with predetermined corresponding data or predetermined test conditions, a predetermined type of vehicle, and a predetermined test site configuration, these data being stored in storage means associated with the analysis means. The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the appended drawings, in which:

- Fig.1 shows a block diagram illustrating the general structure of a determination system according to the invention; - Fig.2 shows a flowchart illustrating an information acquisition phase implemented in a determination system according to the invention;

- Fig.3 shows a flowchart illustrating an information analysis phase implemented in a system according to the invention; - Fig.4 shows an instantaneous deceleration curve of a train to illustrate the calculation of a response time of the braking means thereof;

- Figs.5 and 6 show instantaneous deceleration curves before (Fig.5) and after (Fig.6) smoothing of the corresponding information; and - Fig.7 shows an example of presentation of the results of a vehicle test.

FIG. 1 shows a system for automatically determining the emergency braking characteristics of a public transport vehicle, in particular a rail vehicle.

Conventionally, such a vehicle comprises means for measuring the speed of this vehicle, designated by the general reference 1, means 2 for measuring the distance traveled by it and means 3 for initiating braking d vehicle emergency to activate the braking means thereof, designated by the general reference 4.

The speed measurement means comprise for example a speedometer, the distance traveled measurement means comprise for example an odometer and the triggering means comprise for example an emergency braking button actuable by the driver of the vehicle, classic way.

These various bodies are for example connected to a first information processing unit designated by the general reference 5 and comprising for example any suitable computer, designated by the general reference 6, associated with data storage means designated by the general reference 7.

These different elements are on board a vehicle and the information processing unit is for example adapted to manage the operation of this vehicle from different information from sensors or other information input elements. boarded this one. This information processing unit 5 is also associated with means, designated by the general reference 8, for transmitting information to a tool designated by the general reference 9.

To this end, the information processing unit 5 is associated with interface means designated by the general reference 10, between this unit and any data transmission link designated by the general reference 11.

This connection can for example be provided by wired or other means. The tool 9 also includes corresponding interface means 12 associated with means 13 forming an input buffer, also connected to a second information processing unit designated by the general reference 14. This information processing unit 14 also includes, for example, any suitable computer designated by the general reference 15, associated with data storage means designated by the general reference 16, with user interface means designated by the general reference 17 and comprising, for example in a conventional manner , information display means and information input means by this user

It will also be noted that a printer designated by the general reference 18 can be associated with this information processing unit 14.

Finally, this information processing unit 14 can also be associated with means 19 for storing test base configuration information, vehicle and predetermined test data, which will be described in more detail below.

In fact, the system described comprises means for detecting the activation of the means 3 for triggering the emergency braking of the vehicle and means for detecting the stopping of the latter, which are adapted to activate / deactivate the operation of means for acquiring speed and distance information traveled by the vehicle during the period of time elapsing between this activation of the triggering means and the stopping of the vehicle and means for analyzing this information for issue at least information on the distance traveled by the vehicle during this period. Thus, for example, the detection of the activation of the means for triggering the emergency braking of the vehicle, designated by the general reference 3 in this FIG. 1, can be ensured by the information processing unit 5, which on the one hand, actuates the braking means 4 thereof and on the other hand, activates the operation of the means for acquiring information of speed and distance traveled, delivered by the corresponding means 1 and 2, these means acquisition being for example formed by the tool 9.

This information is in fact transmitted for example by the information processing unit 5 to this tool 9, using the information transmission means 8 described above. The corresponding information is then received in the input buffer means 13 of the unit 14, then possibly stored in the data storage means 16 before processing.

This unit 14 of the tool 9 is in fact adapted to deliver information of the vehicle's emergency braking characteristics, as will be described in more detail below, from information coming from the processing unit. 5.

Is illustrated in Figure 2, a flowchart illustrating this phase of information acquisition. This acquisition phase begins with a step designated by the general reference 20 during which the unit, for example 5, monitors the actuation of the means 3 for triggering the emergency braking of the vehicle.

As soon as these means are actuated, the vehicle speed and distance traveled information are acquired during step 21, for example by the unit 14.

This acquisition continues as long as the vehicle is not stopped, that is to say as long as the speed of the vehicle is not equal to zero, as is determined during step 22. Although of course, additional emergency braking characteristics can be delivered by the processing unit 14.

Indeed, in addition to the information of distance traveled by the vehicle during the stop period, the analysis means formed by the tool 9, can also be adapted to further deliver information on instantaneous deceleration of the vehicle during this period of time. This is then calculated from the information available, by the processing unit 14.

In addition, these analysis means can be adapted to further deliver response time information from the vehicle braking means, following the activation of the emergency braking triggering means.

The determination of this response time will be described in more detail below. Of course, these analysis means can be adapted to deliver the or each braking characteristic of the vehicle in real time or in deferred time.

^* There is illustrated in Figure 3, a flowchart illustrating the processing implemented by the unit 14 to deliver this information.

This flowchart begins with a phase 23 of determining or calculating the corresponding information, that is to say distance traveled, instantaneous deceleration and / or response time of the braking means, from the information acquired. During step 24, the information processing unit 14 can be brought to acquire information relating to the configuration of the terrain of the test base, to make during step 25, corrections to the determined values or calculated, as will be described in more detail later.

This information relating to the configuration of the test base is for example stored in the means 19 associated with the unit 14.

During step 26, the information processing unit 14 can be led to acquire information relating to predetermined corresponding values, of braking characteristics, stored for example also in these means 19. This then allows for example to the processing unit 14 during the step

27, to compare the values delivered with predetermined corresponding data for a predetermined type of vehicle and a predetermined test base configuration, this data also being stored for example in the storage means 19, in order to deliver at 28, a result relating to this comparison and therefore possibly, information relating to the fact that the vehicle and more particularly the braking means thereof, is functioning correctly or not.

By way of correction made to the characteristics delivered, it is for example possible to provide for a correction of the information of distance traveled by the vehicle, determined from the information delivered by the corresponding acquisition means, to take account of the reaction time of these means of acquisition.

We know that these acquisition means, in particular when they use computers, operate at frequencies more or less high. Acquisitions of the corresponding values are therefore made periodically and information can be lost, in particular when the emergency braking is triggered, if this takes place for example during a cycle of the computer, because the effective acquisition of information will not begin until the next cycle.

For safety reasons, it may then be desirable to add to the distance traveled as calculated, the distance that the vehicle could have traveled at most during a cycle of the computer.

This then makes it possible to take account of the reaction time of the acquisition means.

The analysis means also comprise, as indicated above, means making it possible to deliver information on the response time of the braking means following the activation of the means for triggering emergency braking. This is illustrated for example in FIG. 4, where an instantaneous deceleration curve of a train has been shown. The analysis means then comprise means for calculating the response time information, according to the relation: te = tr + tt / 2 where: te: represents the response time; tr: represents the time elapsed between the start of braking until the vehicle acceleration reaches 10% of the deceleration value in steady state; and tt: represents the time elapsed from the start of braking until the deceleration of the vehicle reaches 90% of the deceleration value in steady state.

The value of the deceleration in steady state can then be the arithmetic mean of the points measured in nominal mode. Of course, a calculation other than that described above can be envisaged for this response time.

The cyclic operation of computers can also lead, when the operating frequency of these is low, to significant when determining the deceleration of the vehicle from one computer cycle to another.

It then appears, as illustrated in FIG. 5, a curve exhibiting a phenomenon known as “sawtooth”, linked to a too long period of computers.

To solve this problem, the analysis means can comprise means for smoothing the deceleration information of the vehicle and these smoothing means can for example comprise filtering means with a sliding time window in a conventional manner. This then makes it possible to smooth the deceleration curve as illustrated in FIG. 6.

Of course, other smoothing means can be envisaged.

Finally, the results delivered during the test for example of a particular vehicle, on a particular test basis and under particular conditions, can be compared with predetermined corresponding information, stored for example in the means 19, as has been previously described.

These storage means 19 then contain predetermined test information for predetermined elements. It may then be necessary to make different corrections to the values delivered to allow a coherent comparison between these braking characteristics delivered by the analysis means described above, to predetermined corresponding data for predetermined test conditions, a predetermined type of vehicle. and a predetermined test site configuration.

So for example, it may prove necessary to make corrections linked to the fact that the speed of the vehicle during the test does not quite correspond to the speed of a predetermined test whose characteristics are recorded in these storage means. 19. Of course, different types of correction can be envisaged.

Illustrated in Figure 7, an example of presentation of different information and results obtained during a test of a particular vehicle.

We see appearing in this figure, the instantaneous deceleration curve as noted, this curve being designated by the general reference 29 in this figure, various information relating to the test conditions, such as for example the weather conditions, the speed, etc. , information relating to the vehicle tested, the response time information te designated by the general reference 30 in this figure, measured stopping distance information, designated by the general reference 31 and possibly corrected, designated by the general reference 32, in accordance with what has been described above and various other information making it possible to check that the vehicle and in particular the braking means thereof, is functioning correctly. By way of illustration only, one can for example observe on the deceleration curve, towards the end thereof, a level designated by the general reference 33 which corresponds in the current structure of the braking systems of vehicles of this type, to the release magnetic braking pads, for example of a train, which makes it possible to check their correct operation. These different pieces of information are then stored in the information storage means 16 (FIG. 1), to ensure the preservation and traceability of these tests, and can also be presented visually to an operator, for example on the interface means 17 and possibly printed using the printer 18. It goes without saying of course that still other embodiments of such a system can be envisaged.

Claims

1. System for automatically determining the emergency braking characteristics of a public transport vehicle, in particular a rail vehicle, comprising means (1) for measuring the speed of the vehicle, means (2) for measuring the distance traveled by the latter, and means (3) for triggering an emergency braking of the vehicle to actuate braking means (4) thereof, characterized in that it comprises means (5) for detection activation of the means (3) for initiating the emergency braking of the vehicle and means (5) for detecting the stopping of the vehicle, adapted to activate / deactivate the operation of acquisition means (9) speed and distance information traveled by the vehicle during the period of time elapsing between the activation of the means for triggering the emergency braking and the stopping of the vehicle, and analysis means (9) of these information for delivering at least distance information pa run by the vehicle during this period and response time information (te) of the braking means (4) of the vehicle, following the activation of the means (3) for initiating emergency braking.

2. System according to claim 1, characterized in that the analysis means (9) are adapted to further deliver information on instantaneous deceleration of the vehicle during this period of time.

3. System according to any one of the preceding claims, characterized in that the analysis means (9) are adapted to deliver the or each braking characteristic in real time.

4. System according to any one of claims 1 and 2, characterized in that the analysis means (9) are adapted to deliver the or each characteristic in deferred time.

5. System according to any one of the preceding claims, characterized in that the analysis means (9) comprise means for correcting the information on the distance traveled by the vehicle determined from the information delivered by the means of acquisition, to take into account the reaction time of these acquisition means.

6. System according to any one of claims 2 to 5, characterized in that the analysis means (9) comprise means for smoothing the deceleration information of the vehicle.

7. System according to claim 6, characterized in that the smoothing means comprise filtering means with sliding time window.

8. System according to any one of the preceding claims, characterized in that the analysis means (9) comprise means for calculating the response time information of the braking means (4) according to the relation te = tr + tt / 2 where te represents the response time, tr represents the time elapsed between the start of braking until the vehicle deceleration reaches 10% of the deceleration value in steady state and tt represents the elapsed time from the start of braking until the deceleration of the vehicle reaches 90% of the value of the deceleration in steady state.

9. System according to any one of the preceding claims, characterized in that the analysis means (9) comprise means for comparing the or each braking characteristic delivered to predetermined corresponding data for predetermined test conditions, a predetermined type of vehicle, and a predetermined test site configuration, this data being stored in storage means (19) associated with the analysis means (9).