EP3999396A1

EP3999396A1 - Autonomous driving system for a rail vehicle; associated rail vehicle and method

Info

Publication number: EP3999396A1
Application number: EP20737205.3A
Authority: EP
Inventors: Mustapha BADI; Joan LE FOLL; Cyril Roussillon; Fabien BROSSEAU
Original assignee: Alstom Holdings SA
Current assignee: Alstom Holdings SA
Priority date: 2019-07-15
Filing date: 2020-07-13
Publication date: 2022-05-25
Also published as: WO2021009109A1; FR3098780B1; FR3098780A1

Abstract

Said system (10), which is installed on board a rail vehicle (1) and interfaced with a unit for monitoring/controlling (8) traction/braking means (3, 4) of the vehicle, comprises: a means (21, 23, 33) for determining a position of the vehicle; a means (25, 26, 39) for detecting an obstacle in an observation region around the vehicle; a means for calculating a setpoint speed (37) in order to filter each obstacle detected in the observation region by only retaining the detected obstacle in a monitoring zone, and for calculating a setpoint speed depending on the position of the vehicle and the location of the obstacle in the monitoring zone; and a speed control module (38) for generating, on the basis of the setpoint speed, a setpoint signal designed to be applied to the monitoring/control unit (8).

Description

TITLE: Autonomous driving system of a railway vehicle; railway vehicle and associated method

The field of the invention is that of autonomous driving of a rail vehicle, and more particularly of a tram.

In general, for driving a vehicle (automobile, bus, train, etc.), a reference range of autonomy has been defined which makes it possible to qualify the degree of autonomy with which the vehicle in question is traveling.

In this document, the desired level of autonomy is level "4" of this autonomy scale. In level "4", the operation of acceleration, braking and steering of the vehicle is managed automatically, the operation of monitoring the environment in which the vehicle is moving is managed automatically, and the reaction operation of the vehicle in the event of a problem (presence of an obstacle) is also managed by the vehicle. Level "4" differs from the highest level, level "5", in that the driving of the vehicle in autonomy is limited to certain predefined road sections and not to all the roads on which the vehicle would be required to travel. vehicle. It should be noted that level “0” of this autonomy scale corresponds to the case where all the preceding operations are carried out by the driver and level “1”, in the case where the on-board system offers simple assistance to the driver. vehicle for acceleration, braking and steering operation. Level "1" thus corresponds to driving assistance, commonly referred to as DAS for "Driver Assistance System".

It is desirable to be able to equip a tramway with an autonomous driving system, at least on sidings of the network on which it runs. It is therefore a question of managing the traction and braking of the tram according to the environment of the tram.

The aim of the invention is therefore to solve this problem.

For this the invention relates to an autonomous driving system for a rail vehicle traveling on a track, intended to be loaded on board said rail vehicle and interfaced with a control / command unit for the traction / braking means of the rail vehicle. , the autonomous driving system comprising:

- a means of acquisition, suitable for determining a current position of the rail vehicle;

- an obstacle detection means suitable for detecting and locating an obstacle in an observation region around the rail vehicle;

- a means of calculating the target speed, specific: in filtering the or each obstacle detected in the observation region by retaining only the or each obstacle detected which is situated within a surveillance zone, and,

to calculate a set speed based on the current position of the rail vehicle and the location of an obstacle located inside the surveillance zone; and

- a speed regulation module suitable for generating, from the setpoint speed, a setpoint signal intended to be applied to the control / command unit of the traction / braking means of the rail vehicle,

the surveillance zone being centered laterally on the track and having a width which is a function of a transverse gauge of the rail vehicle.

According to the invention, if the position of the tram along the tracks makes it possible to define a reference speed, the latter is modulated to take into account the presence of an obstacle only if it is in front of the tram. The system thus delivers a setpoint speed to the speed regulation module controlling the traction / braking means of the tram.

Such a system is therefore based on the ability to detect obstacles in front of the tram along the track. Once the location of an obstacle has been determined, the system defines the reaction to be adopted, in particular whether to activate the brake system of the tram and in what proportion.

According to particular embodiments, the autonomous driving system comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:

- the surveillance zone corresponding to a portion of the observation region which follows the route of the track on which the rail vehicle is traveling;

- the surveillance zone extends over a predefined length from the front of the rail vehicle;

- the surveillance zone is equal to the width of the transverse gauge of the rail vehicle (1) increased by a distance of between 20 cm and 40 cm;

- a length of the surveillance zone depends on the instantaneous speed of the rail vehicle;

the surveillance zone is subdivided longitudinally into a plurality of domains, each domain being associated with an action to be implemented in the event of an obstacle located in said domain; - the action associated with a domain is selected from: slowing down, braking and emergency braking; and,

- the implementation of the action consists in weighting a reference speed, which is determined as a function of the current position of the rail vehicle and of a track plan, so as to obtain a reference speed suitable for the action to implement.

The subject of the invention is also a rail vehicle capable of being driven independently, incorporating an autonomous driving system in accordance with the previous system.

The subject of the invention is also a method for autonomous driving of the preceding vehicle, characterized in that it comprises the steps of: determining a current position of the rail vehicle; detect and locate an obstacle in an observation region around the rail vehicle; calculate a target speed by filtering the or each obstacle detected in the observation region by retaining only the or each obstacle detected which is located inside a monitoring zone, and by determining the target speed as a function the current position of the rail vehicle and the location of an obstacle located within the surveillance zone; and, regulating the speed by generating, from the setpoint speed, a setpoint signal intended to be applied to the control / command unit of the traction / braking means of the rail vehicle.

The invention and its advantages will be better understood on reading the detailed description which follows of a particular embodiment, given solely by way of non-limiting example, this description being made with reference to the accompanying drawings in which:

Figure 1 is a schematic representation of a tram equipped with an autonomous driving system according to the invention;

FIG. 2 is a functional representation in the form of blocks of the autonomous driving system of FIG. 1;

FIGS. 3 to 5 schematically represent different areas to be monitored defined in front of the tramway as a function of the configuration of the track on which the tram in FIG. and,

Figure 6 is a schematic representation of an embodiment of the method according to the invention.

In FIG. 1, a railway vehicle is shown, in particular a tramway 1 traveling on a track 2. Conventionally, in order to be able to be driven by a driver, the tramway 1 comprises a control chain for the traction / braking means of the tramway, which are represented schematically in FIG. 1 by a motor 3 and brakes 4.

The control chain comprises, in the cabin, a manipulator 6 allowing the generation of reference signals. The manipulator 6 has a pivoting handle which, when moved forward, allows the driver to request traction force and, when pivoted rearward, allows the driver to request brake force.

For example and preferably, the manipulator can be moved forward in a first position corresponding to an increase of + 50% in the tensile force, or a second position of + 15% in the tensile force. It can be moved back to a first position corresponding to a + 50% increase in braking effort, or a second position of + 15% in braking effort.

The setpoint signal generated by the manipulator 6 is applied to the input of a control / command unit 8 of the traction / braking means. Unit 8 is able to control the traction / braking means by applying suitable control signals developed as a function of the setpoint signal received.

To be able to be driven independently according to level "4" of the scale commonly used for autonomous vehicle driving, tramway 1 is equipped with a self-driving system 10.

The system 10 is suitable for generating setpoint signals of the same type as those generated by the manipulator 6. In this way, the signals generated by the system 10 can be applied directly to the input of the control / command unit 8. replacing the setpoint signals generated by the manipulator 6.

Thus the system 10 uses the existing control channel of the unit 8 and the unit 8 is unchanged from the state of the art.

To be able to switch from a driving mode with a driver to an autonomous driving mode, tramway 1 is advantageously equipped with a two-state switch 12, making it possible to apply a setpoint signal to the input of unit 8. from manipulator 6, i.e. a setpoint signal from system 10.

Advantageously, the state of the switch 12 is controlled by a switch 14 placed in the cabin. Switch 14 is actuated by the driver, for example when tram 1 leaves a network service track to enter a network siding, siding on which independent operation is authorized. The actuation of the switch 14 leads to the toggle of the switch 12.

System 10 has a hardware layer shown in Figure 1. The system 10 comprises, as acquisition means, a plurality of sensors connected at the input of a computing unit 20.

Among the sensors used by the autonomous driving system 10, the tram is equipped with an inertial unit 21 capable of determining instantaneous vector acceleration of the tram and, by time integration, an instantaneous first speed of the tram.

The system also uses tachometric means 22, making it possible to determine a second instantaneous speed of the tramway 1 and, by temporal integration from a reference point along the track, the distance traveled by the tramway from this reference point and consequently a second current position of the tram.

The sensors also include a sensor for a localization system suitable for determining a first current position of the tram. Preferably, in the embodiment presented here in detail, the sensor of the localization system is a LIDAR 23. The LIDAR 23 is a two-dimensional LIDAR having a high opening angle, for example of 270 °, and allowing, by processing the echoes received, to reconstruct the tram environment and to obtain a reconstructed map. The plurality of sensors also include, more particularly for the obstacle detection function, a first LIDAR 25 and a second LIDAR 26.

The first LIDAR 25 is a three-dimensional LIDAR allowing the observation of a first region located in front of tram 1.

The second LIDAR 26 is a two-dimensional LIDAR allowing the observation of a second region located in front of the tram.

The crosschecking of the information delivered by the first and second LIDAR 25 and 26, allows the obstacle detection function to determine the relative position of an obstacle with respect to the front of the tram within a region of extensive observation.

Referring more particularly to Figure 2, which shows the various components of Figure 1 but in functional form, the system 10 will be presented in more detail, including the calculation unit 20.

The calculation unit 20 comprises a LIDAR localization module 33 capable of taking as input the signals delivered by the LIDAR 23 and of generating as output a reconstructed map. This reconstructed map is applied at the input of a location module 32. The temporal evolution of the reconstructed environment also makes it possible to obtain information on the speed of the tram, which is passed to a module 34 for estimating the speed of the tram. The module 34 for estimating the speed of the tram, in addition to the speed at the output of the module 33, takes as input the signals delivered, on the one hand, by the inertial unit 21 and, on the other hand, by the tachometric means 22 .

The function of the module 34 is to deliver a precise estimate of the instantaneous speed of the tram (V in FIG. 1).

This value of the speed delivered at the output of the module 34 is applied, on the one hand, to a speed control module 38 and, on the other hand, to the location module 32.

The location module 32, in addition to the estimation of the instantaneous speed and the reconstructed map, takes as input the information delivered by the inertial unit 21. The function of the location module 32 is to deliver a precise estimate of the instantaneous position of the tram on the tracks.

In the embodiment presented here in detail, the module 32 is based on a map 31 of the region where the tramway 1 is authorized to run independently. It is for example a cartography of the topology of the ground (surface of the ground, buildings, equipment installed permanently, etc.) on which extend the siding tracks of the depot inside which the tram runs in autonomy.

The location module 32 compares the environment reconstructed from the states received by the LIDAR 23 with the map 31 so as to determine a first current position of the tram.

This first position is corrected from the information delivered by the sensors 21 and the integration over time of the speed delivered by the module 34.

The current position of tramway 1 is applied to a mission management module 35 and to a speed calculation module 37.

The mission management module 35 is executed when the switch 12 is flipped to allow the autonomous driving mode.

The module 35 then acquires the current position of the tram to determine where the tram is located on the rail network. Based on this information and possibly other information communicated by a control center, a mission is assigned to tramway 1. This mission may for example consist in indicating to the system 10 whether the tramway 1 must go to park.

The speed calculation module 37 is suitable for defining a reference speed, in particular as a function of the topology of the track on which the tramway 1 is traveling at the current instant. The module 37 therefore defines the reference speed as a function of the current position of the tram and of a network track plan. For example, this reference speed is 10 km / h for a portion of straight track and 7 km / h for a portion of curvilinear track or a portion of track when approaching a switch.

Depending on the information delivered by the obstacle detection module 39, the speed calculation module weights the reference speed so as to deliver a set speed for tram 1. Indeed, if the obstacle detection module detects an obstacle in front of the tram, the reference speed must be reduced to avoid any collision.

The setpoint speed, delivered by the module 37 is applied at the input of the module

38 speed regulation. The latter, by comparing the setpoint speed with the estimate of the current speed of the tram delivered by the module 34, determines a suitable traction or braking force. The corresponding setpoint signal, of the same nature as that generated by the manipulator 6, is applied, via the switch 12, to the control / command module 8 of the traction / braking means of the tram.

The module 39 is suitable for acquiring the signals delivered by the LIDARS 25 and 26.

Module 39 delivers, in the event of an obstacle present inside the region observed by LIDARS 25 and 26, the position of this obstacle in relation to the front of the tram.

The operation of the system 10 in case of detection of an obstacle by the module

39 and, more particularly, the way in which the speed calculation module 37 determines a setpoint speed, will now be presented in relation to FIGS. 3 to 5 and the method of FIG. 6.

Depending on the instantaneous position of tram 1, module 37 determines the type of track on which the tram is running at the current instant. To do this, the module 37 uses, for example, a track plan. The latter associates a type of track with each position of the tram.

Three types of channel are for example predefined. These three types of channels are respectively represented in Figures 3, 4 and 5.

The first type corresponds to a section of straight track.

The second type is a curved track section.

Finally, the third type corresponds to a section of track approaching a switch.

Other types of track can be defined.

Recognizing the type of track on which the tram is traveling allows module 37 to define the value of a reference speed. For example, the speed of reference associated with the first type of track is 10 km / h; the second type of 7 km / h; and the third type of 7 km / h.

Other reference speed values are possible.

In addition, module 37 defines, in front of the tram, a surveillance zone within the observation region of obstacle detection module 39.

The surveillance zone follows the route of the section of track in front of the tram. Determining the type of track thus advantageously makes it possible to determine the geometry of the surveillance zone.

This surveillance zone is centered laterally on the track and has a width which is a function of the transverse gauge of the tram, that is to say which extends laterally on either side of the track so as to correspond substantially to the transverse gauge of the tram 1. For example, the width of the surveillance zone is equal to the overall width of the transverse gauge of the traway (1) increased by a distance of between 20 cm and 40 cm.

The length of the surveillance zone depends on the current speed of the tram.

The surveillance zone filters all of the observations delivered by module 39. Only obstacles whose location falls within the surveillance zone will be retained.

Thus the obstacles detected for module 39 but which are outside the surveillance zone will have no impact on the conduct of the tram. This helps prevent unwanted braking as soon as an object is detected in the environment of the tram, while there is no risk of collision with the latter.

As illustrated in Figure 3, the surveillance zone Z1 for the first type of track takes the form of a rectangle, while for the second type of track, the surveillance zone Z2 takes the form of a torus portion. For the third type of track section and to maximize safety, the system does not take into account the switching state of the switch. As a result, the Z3 surveillance zone covers the two outgoing tracks of the switch.

In a particularly advantageous manner, the surveillance zone is subdivided into domains. For example three domains are defined in the surveillance zone at any time.

Away from the tramway is defined a first area, called slowdown. Then, closer to the tram and in continuity with the deceleration area, a second area, called braking. Finally, between the braking area and the front end of the tram, a third area, called emergency braking. Thus for example in FIG. 3, if an obstacle O is present in the slowing down range D13 of the zone Z1, the module 37 calculates a setpoint speed such as to lead to a reduction in the instantaneous speed of the tram. This can be done passively by using wheel / rail friction forces to gradually reduce the speed of the tram or by applying light braking.

If an obstacle is present in the braking range D12, the module 37 generates a setpoint speed leading to the tram stopping at a minimum safe distance in front of the obstacle. This minimum safety distance is for example 1.2 m.

Finally, if an obstacle is detected in the emergency braking domain D1 1, the module 37 delivers a setpoint speed leading to emergency braking to stop the tram for the shortest possible distance.

Similarly, in Figure 4, the monitoring area Z2 is subdivided into a deceleration domain D23, a braking domain D23 and an emergency braking domain D13.

In FIG. 5, for the case of a section of track approaching a switch, the surveillance zone Z3 is subdivided into a pair of deceleration domains D33 and D33 '(each of these two domains being associated with one of the two tracks exiting the switch), a pair of braking domains D32 and D32 '(each of these two domains being associated with one of the two tracks exiting the switch), and a braking domain emergency D31 (common to the two outgoing tracks of the switch).

Note that Figure 5 shows the surveillance zone as the tram enters the switch, the front of the tram being substantially in line with the switch. There is in fact a continuous evolution of the shape of the surveillance zone between that shown in Figures 3 and 4 and that shown in Figure 5 as a function of the distance from the tram to the switch.

In FIG. 6, the method implemented by the module 37 for calculating the setpoint speed is illustrated in the form of blocks.

In step 1 10, from the current position of the tram and a map of the rail network, module 37 determines the type of track on which tram 1 is running.

In step 120, this information makes it possible to define the reference speed.

In step 130, a surveillance zone is defined at the front of the train. Advantageously, this surveillance zone is defined not only as a function of the type of track on which the tram runs, but also as a function of the speed of the tram. For example, the higher the speed of the tram, the greater the length of the surveillance zone. The surveillance zone is subdivided into three areas, for example according to predefined proportions.

Finally, in step 140, module 37 determines whether an obstacle is detected within the surveillance zone. For this, it uses the obstacle location information determined by module 39.

If no obstacle is located in the surveillance zone, the process is looped back on itself and returns to step 1 10. The process 100 is thus iterated for each sampling period.

On the other hand, if, in step 140, an obstacle is detected, in step 150, the module 37 identifies the domain in which the obstacle is located.

In step 160, depending on the domain identified in step 150, the module 37 chooses an action to be performed from among a slowdown of the tram, a braking of the tram or even an emergency braking.

In step 170, the corresponding speed setpoint is generated and applied to the speed control module 38.

If the obstacle was in the deceleration domain, in step 180 the process loops back to step 140 to determine the evolution of the position of the obstacle. Either the obstacle has left the surveillance zone and the process returns to step 1 10, or the obstacle is still present and steps 150 and following are carried out again.

If at step 140, it had been decided to brake or emergency braking, at the end of step 170, we wait for the tram to come to a stop before performing step 150 to check whether the obstacle has been removed from the track. If so, the tram can be restarted. The process then loops back to step 1 10.

Claims

1. Autonomous driving system (10) for a railway vehicle (1) traveling on a railway track (2), intended to be loaded on board said railway vehicle and interfaced with a control / command unit (8) of the traction means / braking (3, 4) of the rail vehicle, the autonomous driving system (10) comprising:

- an acquisition means (21, 23, 33), suitable for determining a current position of the rail vehicle;

- an obstacle detection means (25, 26, 39) suitable for detecting and locating an obstacle in an observation region around the rail vehicle (1);

- a means for calculating the setpoint speed (37), specific:

in filtering the or each obstacle detected in the observation region by retaining only the or each obstacle detected which is located inside a surveillance zone, and,

- a speed regulation module (38) suitable for generating, from the setpoint speed, a setpoint signal intended to be applied to the control / command unit (8) of the traction / braking means (3, 4) of the rail vehicle, the surveillance zone being centered laterally on the track and having a width which is a function of a transverse gauge of the rail vehicle (1).

2. System according to claim 1, wherein the surveillance zone corresponds to a portion of the observation region which follows the route of the railway track (2) on which the railway vehicle (1) is traveling.

3. System according to claim 2, wherein the surveillance zone extends over a predefined length from the front of the rail vehicle (1).

4. System according to claim 2 or claim 3, wherein the width of the surveillance zone is equal to the width of the transverse gauge of the railway vehicle (1) increased by a distance of between 20 cm and 40 cm.

5. System according to any one of claims 1 to 4, wherein a length of the surveillance zone is a function of an instantaneous speed of the rail vehicle (1).

6. System according to any one of claims 1 to 5, in which the surveillance zone is subdivided longitudinally into a plurality of domains, each domain being associated with an action to be implemented in the event of detection of an obstacle in said. field.

7. System according to claim 6, wherein the action associated with a domain is selected from: slowing down the vehicle, braking to stop the vehicle at a minimum distance from the detected obstacle and emergency braking to stop the vehicle. vehicle for a minimum distance.

8. System according to any one of claims 6 to 7, wherein the implementation of the action consists in weighting a reference speed, which is determined as a function of the current position of the rail vehicle and of a plane of the. channels, so as to obtain a setpoint speed suitable for the action to be implemented.

9. Rail vehicle (1) capable of being driven independently, characterized in that it carries an autonomous driving system in accordance with the system (10) according to any one of claims 1 to 8.

10. A method of autonomous driving of a vehicle according to claim 9, characterized in that it comprises the steps of:

- determine a current position of the rail vehicle;

- detect and locate an obstacle in an observation region around the rail vehicle (1);

- calculate a target speed (37) by filtering the or each obstacle detected in the observation region by retaining only the or each obstacle detected which is located inside a surveillance zone, and by determining the speed setpoint according to the current position of the rail vehicle and the location of an obstacle located within the surveillance zone; and,

- regulate the speed by generating, from the reference speed, a signal of instruction intended to be applied to the control / command unit (8) of the traction / braking means (3, 4) of the rail vehicle (1).