FR3107493A1 - Driving assistance device at an intersection - Google Patents

Abstract

This driving aid device (18) at an intersection (2) is intended to be incorporated into a first motor vehicle (12). The device (18) comprising a module for receiving information (VB, DB) relating to a path followed by a second motor vehicle (14), a processing module capable of determining, as a function of the information received by the receiving module, a risk of collision between the first (12) and second (14) vehicles, and an alert module capable of informing the driver of the first vehicle (12) of a risk determined by the processing module. The reception module comprises a means for exchanging information with a unit (20) arranged on a roadside, the unit (20) being able to display information (VB, DB) relating to a path followed by the second vehicle (14). Figure for the abstract: Fig 1

Description

Driving assistance device at an intersection

The present application relates to an assembly and a method for assisting driving at an intersection.

When a motor vehicle arrives at an intersection, it happens that this vehicle does not have direct visibility to detect vehicles coming from another road and arriving at the intersection. In particular, objects such as buildings, trucks parked on the side can obstruct the visibility between the two vehicles. This results in a greater risk of an accident that affects the safety of the occupants of both motor vehicles. For a vehicle passing another vehicle coming from the right, in a country in which a right-of-way rule is applied, this risk is even greater.

To overcome this drawback, a method has been proposed in which two vehicles communicate by wave to limit the risk of collision between them. Reference may for example be made to document FR 3039120 which describes an example of such a process.

Although the method described in this document effectively makes it possible to reduce the risk of collision between two vehicles, this solution does not provide full satisfaction. Indeed, to operate, it is necessary that each of the two vehicles is equipped with a communication system by waves. However, vehicles are rarely equipped with such a system. In addition, this solution does not work when one of the vehicles is a motorcycle or a bicycle, this type of vehicle being almost never equipped with a wave communication system.

The object of the invention is to remedy the aforementioned drawbacks.

More particularly, the invention aims to limit the risk of a collision between two vehicles at an intersection, even when there is no visibility between the two vehicles and when at least one of the two vehicles is not not equipped with a specific communication device.

To this end, there is proposed an intersection driving aid device intended to be incorporated in a first motor vehicle comprising a module for receiving information relating to a trajectory followed by a second motor vehicle, a module for processing capable of determining, as a function of the information received by the reception module, a risk of collision between the first and second vehicles, and an alert module capable of informing the driver of the first vehicle of a risk determined by the processing module.

According to a general characteristic of this device, the reception module comprises means for exchanging information with a unit located on a roadside and preferably georeferenced, the unit being able to display and/or communicate to said first vehicle information relating to a trajectory followed by the second vehicle.

Such a device makes it possible to provide driving assistance to prevent collisions in intersections effectively, even if the second vehicle is not equipped with a communication device and even in the event of an obstacle preventing the first vehicle from see the second vehicle.

Preferably, the unit is capable of determining crossing origin information, the crossing origin information being on the left if the second vehicle must arrive at the intersection on a left side of the first vehicle, and the origin of crossing being on the right if the second vehicle must arrive at the intersection on a right side of the first vehicle, the processing module being configured to determine a different risk according to the information of origin of crossing.

The device thus configured makes it possible to take account of a right and/or left priority rule.

It is also possible to provide a calculation module able to calculate a setpoint speed if the processing module determines that there is a risk of collision between the first and second vehicles.

Such a calculation module makes it possible to suggest to the driver of the first vehicle a corrective action to ensure good safety for the occupants of the vehicles.

In one embodiment, the calculation module is configured to calculate the setpoint speed taking into account a maximum deceleration value with a view to a predetermined level of comfort.

Advantageously, the processing module comprises a determination module configured to detect a dangerous situation if the calculation module fails to calculate a setpoint speed by taking into account the maximum deceleration value with a view to the predetermined level of comfort.

Such a determination module makes it possible to alert the driver in the event of a significant risk so that he undertakes emergency braking action sufficiently early.

Advantageously, the calculation module is configured to calculate the setpoint speed as a root of a polynomial whose coefficients are determined as a function of at least one datum chosen from among the maximum deceleration with a view to the predetermined comfort level, the time remaining for the second vehicle to arrive at the intersection, a safety factor greater than or equal to 2, a predetermined safety interval taking into account measurement inaccuracies, the length of the second vehicle and the width of the first vehicle, the time reaction of a man-machine interface of the first vehicle to send the setpoint speed information to a driver of the first vehicle, the reaction time of the driver to decide to reduce his speed, the reaction time of the man-machine interface to transmit the target speed to a traction control device of the first vehicle, the speed of the first vehicle, and the distance between the first vehicle and the intersection.

According to another aspect, there is proposed an intersection driving aid assembly comprising a device as defined previously, the device being intended to be incorporated into a first motor vehicle, the assembly comprising a unit intended to be placed roadside, the unit comprising a means of displaying at least a second motor vehicle and a means of communication capable of exchanging information with the device, the means of communication being configured to send to the device information relating to the trajectory followed by the second vehicle.

In an advantageous embodiment, the visualization means comprises a 360° lidar.

Alternatively, the display means comprises at least one camera.

In a particularly advantageous embodiment, the display means comprises four cameras.

Preferably, the means of communication is capable of exchanging, with the device, at least one piece of information chosen from a speed of the first vehicle, a distance between the first vehicle and the intersection, a speed of the second vehicle, and a distance between the second vehicle and the intersection.

Advantageously, the display means of the unit is georeferenced so as to know its absolute GNSS position.

The unit thus designed can be placed at an intersection to effectively alert in the event of a risk of collision between two vehicles that cannot be seen due to an obstacle.

It is also possible to provide at least one target arranged at a predetermined distance from the display means.

The display means of the unit can thus be geocalibrated, which makes it possible, combined with its referencing, to accurately determine position information and/or vehicle speed information.

According to yet another aspect, there is proposed a method for assisting driving at an intersection implemented by means of an assembly as defined previously, in which the unit displays the first vehicle and the second vehicle, the unit sends to the device information relating to the trajectory followed by the second vehicle, the device determines whether there is a risk of collision between the first and second vehicles and, if the device determines that there is a risk, the device alerts a driver of the first vehicle of the determined risk.

Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

schematically represents an intersection and a set of pipe according to one aspect of the present invention,

schematically represents a driving aid device of the assembly of FIG. 1,

schematically represents a roadside unit of the assembly of Figure 1, and

schematically represents a driving assistance method that can be implemented at the intersection of Figure 1.

Referring to Figure 1, an intersection 2 is formed between four roads 4, 6, 8 and 10. It is possible, without departing from the scope of the invention, to consider a different intersection, in particular an intersection formed by another number of roads and/or an intersection formed by roads forming between them an angle different from a right angle.

In the example shown, a first vehicle 12 is traveling on road 4 towards intersection 2 and a second vehicle 14 is traveling on road 6 towards intersection 2. In the example shown, vehicles 12 and 14 travel on the right of roads 4 and 6. Thus, the example shown is located in a context in which vehicles normally drive on the right. However, without departing from the scope of the invention, it is possible to envisage a context in which the vehicles normally travel on the left. Vehicle 12 will have to yield to vehicle 14 at intersection 2, under right-hand priority rules. It is possible without departing from the scope of the invention to consider an example in which the priority system between vehicles is different, for example an intersection in a country applying a rule of priority to the left or an intersection comprising a "stop" or " yield".

The front face of the vehicle 12 is located at a distance D _A from the intersection 2 and travels at a speed V _A . The vehicle 14 is located at a distance D _B from the intersection 2 and travels at a speed V _B . In the present application, the position of intersection 2 is defined as the intersection of the middles of the lanes concerned.

An obstacle 16 is arranged between roads 4 and 6, so as to obstruct visibility between vehicles 12 and 14. In this case, obstacle 16 is a building. However, without departing from the scope of the invention, it is possible to envisage another type of obstacle arranged between the roads 4 to 10, or else on the side or on one of the roads 4 to 10.

The vehicle 12 is equipped with a driving aid device 18 . A roadside unit 20 is arranged along roads 4 and 6, at the level of the intersection 2. The driving aid device 18 and the roadside unit 20 together form an aid assembly to driving at the intersection 2. The driving aid 18 is shown in detail in Figure 2 and the roadside unit 20 is shown in detail in Figure 3.

Referring to Figure 2, the device 18 comprises a reception module 22 provided with wireless communication means 24.

The device 18 comprises a processing module 26 in communication of information with the reception module 22. The processing module 26 has the function, from the data received by the reception module 22, of detecting a risk of collision between the vehicles 12 and 14.

The processing module 26 comprises a determination module 28. The determination module 28 is capable of determining whether there is a particularly dangerous situation when there is a risk of collision between the vehicles 12 and 14.

The device 18 comprises a calculation module 30. The calculation module 30 is in communication of information with the reception module 22 and with the processing module 26. More particularly, the function of the calculation module 30 is to calculate a speed as a function of data received by the reception module 22, when the processing module 26 has identified a risk of collision between the vehicles 12 and 14.

The device 18 comprises an alert module 32. The function of the alert module 32 is to inform a driver of the vehicle 12 of a risk of collision determined by the processing module 26, of a set speed calculated by the calculation module 30 and of a particularly dangerous situation determined by the determination module 28. In the example illustrated, the alert module 32 comprises a vehicle on-board screen alert sound.

Referring to Figure 3, roadside unit 20 includes wireless communication means 34. Wireless communication means 34 is in information communication with wireless communication means 24. In other In other words, the receiving module 22 is able to exchange information with the roadside unit 20.

The roadside unit 20 comprises four cameras 36, 38, 40 and 42 arranged so as to visualize the roads 4, 6, 8 and 10 respectively. In this way, the cameras 36 to 42 have a 360° vision allowing to visualize all the vehicles arriving at the intersection 2. In particular, the cameras 36 and 38 respectively identify the vehicles 12 and 14.

Without departing from the scope of the invention, a different number of cameras can be envisaged. Preferably, the roadside unit 20 comprises at least the cameras 36 and 38. The cameras arranged facing roads 8 and 10 can be arranged in another roadside unit (not shown) located between roads 8 and 10 , close to the intersection 2. Similarly, it is not beyond the scope of the invention to envisage a means of viewing different from the cameras 36 to 42, for example a 360° lidar.

Nor is it departing from the scope of the invention by considering a different location of the roadside unit 20. For example, the roadside unit can be located on a roundabout (not shown) of intersection 2.

The cameras 36 to 42 are also capable of determining the distances between an approaching vehicle and the intersection 2 and the speed of such a vehicle. Therefore, the camera 36 determines the distance D _A and the speed V _A , and the camera 38 determines the distance D _B and the speed V _B . Further, the roadside unit 20 detects crossing origin information PROV related to the respective vehicles 12 and 14. In this case, the crossing origin information PROV(12) linked to vehicle 12 is on the right because vehicle 14 will arrive at intersection 2 on the right of vehicle 12. The crossing origin information PROV(14) linked to vehicle 14 is on the left because vehicle 12 will arrive at intersection 2 on the left of vehicle 14.

Referring to Figure 4, there is schematically shown an example of a method that can be implemented by means of the driving assistance assembly consisting of the device 18 and the unit 20.

The method includes an initialization step E01 during which the vehicle 12 approaches the intersection 2. The step E01 is preferably implemented periodically, for example every tenth of a second. As a result, device 18 and unit 20 enter into information communication via their wireless communication means 24 and 34.

For example, step E01 can correspond to two sub-steps, namely:

- a sub-step a in which the device 18 determines the position of the vehicle 12 on a navigation map, in this case by identifying, on the navigation map, the section of road on which the vehicle 12 is located, and

- a sub-step b in which the device 18 identifies that the vehicle 12 is on a section of road which goes towards the intersection 2.

The method comprises a step E02 during which the reception module 22 receives information on the detection of the vehicle 14 by the camera 38, and data D _B , V _B , D _A and V _A . Alternatively, the data V _A can be supplied by the on-board computer of the vehicle 12 via a communication V2I.

More specifically, during step E02, device 18 can implement the following sub-steps:

- a sub-step a in which the device 18 retrieves the GPS position of the vehicle B and its speed vector V _B via the communication system of the roadside unit,

- a sub-step b in which the device 18 positions the vehicle B on the electronic navigation map,

- a sub-step c in which the device 18 identifies, on the navigation map, a section of road on which the vehicle 14 is located,

- a sub-step d in which the device 18 identifies that the vehicle 14 is on the right lane which goes towards the intersection 2,

- A sub-step e in which the device 18 determines the distance D _B and collects the data D _A and V _A .

The method comprises a step E03 for determining the existence of a risk of collision between the vehicles 12 and 14. More specifically, during step E03, the processing module 24 determines the remaining times T _A , T _B so that the respective first, second vehicles 12, 14 arrive at the intersection 2, by applying the equations:

Still during step E03, the processing module 24 estimates the time interval I in which the vehicle 12 must avoid arriving at the intersection 2 so as not to find itself too close to the vehicle 14. More in particular, during step E03, the processing module 24 determines the interval I by applying:

where T _S is a safety time and K _S is a safety factor. The time T _S is estimated by calibration taking into account the inaccuracies of measurement and the width of the vehicle 12. In this case, the time T _S is determined according to the length of the vehicle 14 and the width of the vehicle 12. For example, the time T _S is equal to 0.5 seconds. The coefficient K _S is a safety coefficient preferably greater than or equal to 2. In this case, the coefficient K _S is equal to 2.

During step E03, if and only if the processing module 24 determines that the time T _A is included in the interval I, there is a risk of collision between the vehicles 12 and 14.

At the end of step E03, if the answer is “no”, the method is terminated.

If, at the end of step E03, the answer is "yes", a test step E04 is applied during which it is determined whether a calculation of a setpoint speed taking into account a maximum deceleration for applying a predefined comfort level is possible. More particularly, during step E04, a maximum deceleration DC _MAX is determined for the vehicle 12 as a function of a level of comfort chosen by a driver of the vehicle 12. Furthermore, the reception module 22 receives, coming from the vehicle 12:

- a predetermined duration T_HMI1, for example 0.2 seconds, corresponding to the reaction time of the vehicle's man-machine interface system 12 to send speed reduction information back to the driver,

- a predetermined duration T _COND , for example 1 second, corresponding to the reaction time of the driver of vehicle 12 to decide to reduce his speed and send the order to the man-machine interface, and

- a predetermined duration T_HMI2, for example 0.2 seconds, of reaction of the man-machine interface system to transmit the speed reduction information to a traction control device of the vehicle 12, and

- an _activation duration T to activate the speed reduction proposal to the vehicle 12 from V _A to V _AC .

To estimate the _activation time T, the calculation module 30 applies the formula:

where V _CA is the reduced setpoint speed to be fed back to the driver so that vehicle 12 arrives at intersection 2 after vehicle 14 has passed through intersection 2.

The maximum comfort deceleration DC _max is preferably equal to −4 ms ⁻² . The maximum comfort deceleration DC _max and the times T _IHM1 , T _COND and T _IHM2 are constant parameters which are predetermined by calibration during the development of the device 18.

A variant of the method according to the invention may comprise the automatic imposition, without driver validation, of the speed reduction on the traction system. In such a variant, the durations T _COND , T _IHM1 and T _IHM2 are preferably zero. Such a variant could in particular be used in the case where the major part, or all of the roundabouts or intersections are equipped with roadside units such as the roadside unit 20.

During step E04, the calculation module 30 determines the setpoint time T _CA corresponding to the duration between the moment when the vehicle 12 has finished its deceleration phase at the setpoint speed and the moment when the vehicle 12 arrives at intersection 2 after vehicle 14 has passed through intersection 2. Time T _CA is calculated as follows:

During step E04, the calculation module 30 determines the distance D _CA corresponding to the distance between the position where the vehicle 12 has finished its deceleration phase at the set speed and the position of the intersection 2. The distance D _CA is calculated as follows:

where D _{ihm_cond} is the distance traveled before the effective speed reduction begins, D _activation is the distance during the speed reduction phase from the initial speed to the set speed. The distance D _{ihm_cond} is calculated as follows:

The deceleration being constant, the speed evolves in a linear way, therefore the distance D _activation evolves in a quadratic way according to the following formula:

However, the reference speed V _AC is expressed as:

Combining equations 5, 6, 7, 8, 9, and 10 yields the equation:

By defining the following constants:

we get the equation:

The calculation module 30 determines the discriminant Δ of equation 13, which is written in the form:

Still during step E04, the calculation module 30 determines whether the discriminant Δ is positive or negative. If the discriminant Δ is negative, the response at step E04 is “no”. If the discriminant Δ is positive, the response at step E04 is “yes”.

If, at the end of step E04, the answer is "no", a step E05 is applied during which the determination module 28 determines that there is a particular situation of danger, in which the vehicle 12 risks to collide with the vehicle 14 without it being possible to reduce the speed by applying an acceleration less than the maximum deceleration DC _max . Consequently, during step E05, the alert module 32 informs the driver of the vehicle 12 of the particularly dangerous situation determined by the determination module 28.

If, at the end of step E04, the answer is "yes", a step E06 is applied for calculating the setpoint speed V _CA . During step E06, the module 30 calculates the speed(s) V _CA as being, in the example illustrated, the solution of equation 13 between 0 and V _A . In other words, the calculation module 30 applies the equation:

and takes the value of the maximum value of v1 and v2 whose values are between 0 and

The method includes a step E07 for determining the information PROV(12). In this case, during step E07, the reception module 22 detects the information PROV(12) on the right, because the vehicle 14 arrives at the intersection 2 on the right of the vehicle 12.

Under these conditions, a step E08 is applied during which the alert module 32 informs the driver of the vehicle 12 of the risk of collision with the vehicle 14, of the priority of the vehicle 14 over the vehicle 12 by virtue of the priority rules on the right and a suggestion to reduce the speed of the vehicle 12 to the setpoint speed V _CA calculated during step E06.

At the end of step E08, a test step E09 is applied during which it is detected whether the driver of vehicle 12 decides to accept the speed reduction suggestion proposed during step E08. As long as the driver has not accepted the speed reduction suggestion, step E09 continues to be applied.

As soon as the driver of the vehicle 12 decides to apply the speed reduction suggested during the step E08, a step E10 is applied during which the device 18 communicates to a vehicle traction control device 12 the information of reference speed V _AC and maximum deceleration DC _max . As a result, vehicle 12 slows down to speed V _CA , decelerating at deceleration DC _max , and vehicle 12 arrives at intersection 2 after vehicle 14 has passed.

If, during step E07, the information PROV(12) was on the left, a step E11 would have been applied during which the alert module 32 informs the driver of the vehicle 12 of the risk of collision with another non-priority vehicle, and a speed reduction suggestion.

Again with reference to Figure 1, the driving aid assembly further comprises two sights 44 and 46 disposed on the respective sides of the roads 4 and 6, at a distance D ₀ from the roadside unit 20. The sights 44 and 46 make it possible to geo-calibrate the display means formed by the cameras 36 and 42, so as to improve the precision of the detection of information relating to the trajectory of the vehicles 12 and 14.

In view of the foregoing, the invention makes it possible to improve the safety of the occupants of the vehicles 12 and 14 arriving at the intersection 2, and this despite the presence of the obstacle 16 obstructing the visibility between the vehicles 12 and 14, and regardless of whether the vehicle 14 is equipped with a driver assistance device like the vehicle 12.

Claims (10)

Driving aid device (18) at an intersection (2) intended to be incorporated into a first motor vehicle (12) comprising a module (22) for receiving information (V _B , D _B ) relating to a trajectory followed by a second motor vehicle (14), a processing module (26) capable of determining, as a function of the information received by the reception module (22), a risk of collision between the first (12) and second (14) vehicles, and an alert module (32) capable of informing the driver of the first vehicle (12) of a risk determined by the processing module (26), the reception module (22) comprising means ( 24) to exchange information with a georeferenced unit (20) arranged on a roadside, the unit (20) being capable of displaying and communicating to said first vehicle (12) information (V _B , D _B ) relating to a trajectory followed by the second vehicle (14), characterized in that it comprises a calculation module (30) capable of calculating a target speed if the processing module (26) determines that there is a risk of collision between the first (12) and second (14) vehicles. Device (18) according to claim 1, in which the calculation module (22) is configured to calculate the setpoint speed (V _AC ) taking into account a maximum deceleration value with a view to a predetermined level of comfort. Device (18) according to Claim 2, in which the processing module (26) comprises a determination module (28) configured to detect a dangerous situation if the calculation module (30) fails to calculate a set speed by taking into account the maximum deceleration value in view of the predetermined comfort level. Device (18) according to Claim 2 or 3, in which the calculation module (30) is configured to calculate the setpoint speed as a root of a polynomial whose coefficients are determined as a function of at least one datum chosen from among the maximum deceleration in view of the predetermined level of comfort, the time (T _B ) remaining for the second vehicle (14) to arrive at the intersection (2), a predetermined safety interval taking into account the measurement inaccuracies, the length of the second vehicle (14) and the width of the first vehicle (12), the reaction time (T _IHM1 ) of a man-machine interface of the first vehicle (12) to send the set speed information to a driver of the first vehicle (12), the reaction time (T _COND ) of the driver to decide to reduce his speed, the reaction time (T _IHM2 ) of the man-machine interface to transmit the set speed to a speed control device the traction of the first vehicle (12), the speed (V _A ) of the first vehicle (12), and the distance (D _A ) between the first vehicle (12) and the intersection (2). An intersection driving aid assembly (2) comprising a device (18) according to any one of claims 1 to 4, the device (18) being intended to be incorporated in a first motor vehicle (12), the assembly comprising a unit (20) intended to be placed on the side of the road, the unit comprising a means of display (36, 38, 40, 42) of at least one second motor vehicle (14) and a means of communication (34) capable of exchanging information with the device (18), the communication means (34) being configured to send the device (18) information (V _B , D _B ) relating to the trajectory followed by the second vehicle ( 14). Assembly according to Claim 5, in which the display means comprises a 360° lidar and/or at least one camera, preferably four cameras (36, 38, 40, 42). Assembly according to Claim 5 or 6, comprising at least one staff (44, 46) placed at a predetermined distance (D ₀ ) from the display means (36, 38, 40, 42). Assembly according to any one of Claims 5 to 7, in which the means of communication (34) is capable of exchanging, with the device (18), at least one piece of information chosen from among a speed (V _A ) of the first vehicle (12 ), a distance (D _A ) between the first vehicle (12) and the intersection (2), a speed (V _B ) of the second vehicle (14), and a distance (D _B ) between the second vehicle (14) and the intersection (2). Assembly according to any one of Claims 5 to 8, in which the unit (20) is adapted to determine crossing coming from information, the crossing coming from information being on the left if the second vehicle (14) is to arrive at the intersection (2) on a left side of the first vehicle (12), and the crossing origin information being on the right if the second vehicle (14) is to arrive at the intersection (2) on a right side of the first vehicle (12), the processing module (26) being configured to determine a different risk as a function of the crossing origin information. A method of assisting driving at an intersection (2) implemented by means of an assembly according to any one of claims 5 to 9, in which the unit (20) displays (E01) the first vehicle (12 ) and the second vehicle (14), the unit (20) sends (E02) to the device (18) information (V _B , D _B ) relating to the path followed by the second vehicle (14), the device (18 ) determines (E03) whether there is a risk of collision between the first (12) and second (14) vehicles and, if the device (18) determines that there is a risk, the device (18) alerts (E08, E11) a driver of the first vehicle (12) of the determined risk.