Method and device for controlling the speed of a vehicle based on a target vehicle

Description

Technical field

[0001] The present invention claims priority from French application 2106018 filed on 06 / 08 / 2021. The invention relates to methods and devices for regulating the speed of a vehicle, in particular a motor vehicle, from a target vehicle when the vehicle changes lane. Technological background

[0002] With the expansion of the road network and the increase in the number of traffic lanes, road safety has become a major concern. Indeed, with the increasing number of vehicles on the road network, the risk of collisions increases, especially on roads with multiple traffic lanes.

[0003] To improve road safety, some vehicles are equipped with driver assistance systems or features, known as ADAS (Advanced Driver Assistance System). To ensure the proper functioning of these driver assistance systems, precise knowledge of the environment around the vehicle is necessary.

[0004] One of these ADAS systems commonly used in vehicles is an adaptive cruise control (ACC). An ACC is an electronic device that increases the comfort and safety of occupants and other road users in general, whether driving in built-up areas, on roads or highways. In addition to the classic cruise control functions, an ACC adapts the vehicle's speed according to the flow of vehicles in front of it. To do this, a sensor is installed at the front of the vehicle to monitor the flow of vehicles in front of it. If this sensor detects a target vehicle traveling in front of it at a slower speed within its range, the ACC deactivates the cruise control, which is then subject to a set speed, and reduces the vehicle's speed to maintain a sufficient safety distance from the target vehicle. If necessary, the ACC can activate a brake command.If the target vehicle changes lane or accelerates, the ACC regulator increases the vehicle speed until it reaches the set speed and then activates the cruise control, which is then again subject to this set speed.

[0005] When a vehicle, whose speed is regulated by an ACC, changes lanes, a problem of choosing the target vehicle can arise when several vehicles precede this vehicle: one traveling on the traffic lane on which the vehicle is traveling and another traveling on the traffic lane on which the vehicle will travel once it has changed lanes. Selecting one of these two vehicles as a target vehicle requires significant computational resources that go beyond the capabilities of current ACC regulators.

[0006] Furthermore, the state of the art is known from document DE19637245A1.

[0007] One problem is to select a target vehicle for adaptive cruise control of a vehicle when that vehicle is changing lanes. Summary of the invention

[0008] An object of the present invention is to improve the knowledge of the environment of a vehicle.

[0009] Another object of the present invention is to improve adaptive vehicle cruise control.

[0010] Another object of the present invention is to improve road safety.

[0011] According to a first aspect, the invention relates to a method for regulating the speed of a vehicle from a target vehicle, said method being implemented by at least one processor, said method comprising a step of detecting a change of traffic lane of the vehicle from a first traffic lane, on which the vehicle is traveling, to a second traffic lane, on which the vehicle will travel when the change of traffic lane is completed, the second traffic lane being delimited by an edge line and a separation line; a step of detecting a first target vehicle traveling in the first traffic lane and a second target vehicle traveling in the second traffic lane; and a step of obtaining a first lateral distance between the first target vehicle and the edge line and a second lateral distance between the second target vehicle and the edge line;the speed of the vehicle then being regulated relative to the first target vehicle if the first lateral distance is less than the second lateral distance, and to the second target vehicle if the first lateral distance is greater than the second lateral distance.;

[0012] According to a particular and non-limiting exemplary embodiment, the first traffic lane being delimited by an edge line and the dividing line, the change of traffic lane is detected by comparing lateral distances of the vehicle with respect to the edge lines of the first and second traffic lanes.

[0013] According to a particular and non-limiting example of embodiment, a shore line is represented by a polynomial.

[0014] According to a particular and non-limiting exemplary embodiment, the edge line of the first traffic lane is represented by a polynomial of degree 3 whose constant value is equal to a third lateral distance between the vehicle and the edge line of the first traffic lane, and the edge line of the second traffic lane is represented by a polynomial of degree 3 whose constant value is equal to a fourth lateral distance between the vehicle and the edge line of the second traffic lane.

[0015] According to a particular and non-limiting exemplary embodiment, a line existence index being associated with each line marked on the ground of the traffic lanes, the first, second, third and fourth distances are obtained if the existence indices of the edge lines of the first and second traffic lanes are greater than a threshold.

[0016] According to a second aspect, the invention relates to a device for regulating the speed of a vehicle from a target vehicle, the device comprising a memory associated with a processor configured for implementing the steps of the method according to the first aspect of the invention.

[0017] According to a third aspect, the invention relates to a vehicle, for example of the automobile type, comprising a device as described above according to the second aspect of the invention.

[0018] According to a fourth aspect, the invention relates to a computer program which comprises instructions adapted for executing the steps of the method according to the first aspect of the invention, in particular when the computer program is executed by at least one processor.

[0019] Such a computer program may use any programming language, and may be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other desirable form.

[0020] According to a fifth aspect, the invention relates to a computer-readable recording medium on which is recorded a computer program comprising instructions for carrying out the steps of the method according to the first aspect of the invention.

[0021] On the one hand, the recording medium may be any entity or device capable of storing the program. For example, the medium may include a storage medium, such as a ROM memory, a CD-ROM or a microelectronic circuit type ROM memory, or a magnetic recording medium or a hard disk.

[0022] Furthermore, this recording medium may also be a transmissible medium such as an electrical or optical signal, such a signal being able to be conveyed via an electrical or optical cable, by conventional or terrestrial radio or by self-directed laser beam or by other means. The computer program according to the invention may in particular be downloaded from a network such as the Internet.

[0023] Alternatively, the recording medium may be an integrated circuit in which the computer program is incorporated, the integrated circuit being adapted to perform or to be used in performing the method in question. Brief description of the figures

[0024] Other characteristics and advantages of the invention will emerge from the description of the non-limiting embodiments of the invention below, with reference to figures 1 to 3 annexed, on which: [ Fig. 1] schematically illustrates a road environment for implementing a method for regulating the speed of a vehicle from a target vehicle, according to a particular and non-limiting exemplary embodiment of the present invention; [ Fig. 2 ] schematically illustrates a device configured to regulate the speed of a vehicle from a target vehicle of the road environment of the Figure 1 , according to a particular and non-limiting embodiment of the present invention; and [ Fig. 3 ] illustrates a flowchart of the different stages of a method for regulating the speed of a vehicle from a target vehicle in the road environment of the Figure 1 , according to a particular and non-limiting exemplary embodiment of the present invention. Description of the embodiments

[0025] A method and device for regulating the speed of a vehicle from a target vehicle will now be described in the following with joint reference to figures 1 to 3 . The same elements are identified with the same reference signs throughout the description which follows.

[0026] According to a particular and non-limiting example of embodiment of the invention, a method for regulating the speed of a vehicle from a target vehicle comprises detecting a change of traffic lane of the vehicle from a first traffic lane, on which the vehicle is traveling, to a second traffic lane, on which the vehicle will travel, the first traffic lane being delimited by a first edge line and a separation line and the second traffic lane being delimited by a second edge line and the separation line. The method also comprises detecting a first target vehicle traveling in the first traffic lane and a second target vehicle traveling in the second traffic lane and obtaining a first lateral distance, between the first target vehicle and the second edge line, and a second distance between the second target vehicle and the second edge line.The vehicle speed regulation is then regulated relative to the first target vehicle if the first distance is less than the second distance, and to the second target vehicle if the first distance is greater than the second distance.

[0027] The comparison of distances evaluated between an edge line of the second traffic lane (on which the vehicle will travel once it has completed its lane change), makes it possible to regulate the speed of this vehicle in relation to a second target vehicle (which is already traveling on this second traffic lane). The method avoids abrupt changes in speed regulation when a first target vehicle (traveling on the first traffic lane on which the vehicle is traveling before the lane change) and the second target vehicle do not have the same speed because the speed regulation takes into account the second target vehicle as soon as a lane change is detected.

[0028] [ Fig. 1] schematically illustrates a road environment 1 for implementing a method for regulating the speed of a vehicle from a target vehicle, according to a particular and non-limiting exemplary embodiment of the present invention.

[0029] There Figure 1 illustrates a road environment 1 comprising for example a road with several traffic lanes 10 and 11, that is to say with several traffic lanes in a given direction of traffic. The road environment 1 corresponds for example to a portion of expressway, for example a portion with 2 times 2 traffic lanes (2 lanes in one direction and 2 lanes in the other direction).

[0030] A vehicle 101 and a vehicle 102 are traveling on a first traffic lane 10. A vehicle 103 is traveling on a second traffic lane 11. The indicator of the vehicle 101 is activated to indicate that the vehicle 101 is going to change traffic lanes, moving from the first traffic lane 10 to the second traffic lane 11 located on the left of the traffic lane 10. Right and left are defined relative to the direction of travel of the vehicle 101.

[0031] The present invention is not limited to the traffic lane change described in Figure 1 but extends to the change of traffic lane passing from a first traffic lane to a second traffic lane located on the right of the first traffic lane.

[0032] The first traffic lane 10 and the second traffic lane 11 are materialized (delimited) by ground markings corresponding to lines drawn on the ground. The first traffic lane 10 is delimited by a first edge line 14 and a separation line 13 and the second traffic lane 11 is delimited by a second edge line 12 and the separation line 13. The lines 12, 13 and 14 are advantageously determined from data obtained by the vehicle 101. These data are for example obtained by a ground marking detection system on board the vehicle 101. Such a system comprises one or more cameras for acquiring images of the road in front and on the sides of the vehicle 101.Image processing is applied to these images to determine the presence of ground lines and to classify these lines into different categories, for example to determine whether the ground lines correspond to edge lines or traffic lane separation lines for example. An example of image processing to detect ground lines is for example described in document WO2017194890A1.

[0033] In a first operation, the vehicle 101 detects a change of traffic lane from the first traffic lane 10, on which it is traveling, to the second traffic lane 11, on which it will travel when the change of traffic lane is completed.

[0034] According to a particular and non-limiting exemplary embodiment, the change of traffic lane is detected by comparing lateral distances of the vehicle 101 with respect to the first shore line 14 and the second shore line 12.

[0035] According to a particular and non-limiting exemplary embodiment, the lateral distances of the vehicle 101 relative to the shore lines are evaluated from information resulting from processing of images obtained by one or more cameras of the line detection system located on the sides of the vehicle 101.

[0036] According to a particular and non-limiting example of embodiment, the first 14 and the second 12 shore lines are represented by a polynomial, for example of degree 3.

[0037] A polynomial of degree 3 is given by: y = A 3 x 3< + A 2 x 2< + A 1 x + A 0 with A 0 a constant value, A 3, A 2 and A 1coefficients of the polynomial and (x,y) coordinates expressed in a reference frame of the vehicle 101. For example, the reference frame of the vehicle 101 is defined by a plane (o,X,Y) of which an origin o is a point located on the vehicle 101, an abscissa axis X extends from the origin o towards the front of the vehicle 101 and an ordinate axis Y extends from the origin o towards the left of the vehicle 101.

[0038] According to a particular and non-limiting exemplary embodiment, the first edge line 14 is represented by a polynomial of degree 3 whose constant value A 0 is equal to a third lateral distance D3, expressed in the frame of reference of the vehicle 101, between the vehicle 101 and the first edge line 14, and the second edge line 12 is represented by a polynomial of degree 3 whose constant value A 0 is equal to a fourth lateral distance D4, expressed in the frame of reference of the vehicle 101, between the vehicle 101 and the second edge line 12.

[0039] A lateral distance of the vehicle 101 from a shore line is defined by the interval which extends perpendicularly from the X axis to the polynomial of degree 3 which represents this shore line.

[0040] In a second operation, the vehicle 101 detects a first target vehicle, in this case the vehicle 102, traveling in the first traffic lane 10 and a second target vehicle, in this case the vehicle 103, traveling in the second traffic lane 11.

[0041] According to a particular and non-limiting exemplary embodiment, the vehicle 101 comprises an object detection system for detecting the first and second target vehicles. An object detection system comprises, for example, millimeter wave radars arranged on the vehicle 101, for example at the front, at the rear, on each front / rear corner. Each radar is adapted to emit electromagnetic waves and to receive the echoes of these waves returned by one or more objects, for the purpose of detecting obstacles and their distances from the vehicle 101, for example.According to another example, an object detection system comprises one or more LIDAR(s) (from the English "Light Detection And Ranging") and / or one or more cameras (associated or not with a depth sensor) to detect objects in the environment of the vehicle 101, their distance from the vehicle 101 and possibly their shape or part of their shape (by three-dimensional modeling for example). A target vehicle is detected when a position of a point located on this target vehicle is obtained by the on-board object detection system of the vehicle 101.

[0042] In a third operation, the vehicle 101 obtains a first lateral distance D1 between the first target vehicle 102 and the second shore line 12, and a second lateral distance D2 between the second target vehicle 103 and the second shore line 12.

[0043] According to a particular and non-limiting exemplary embodiment, the vehicle 101 comprises an object detection system which determines and records successive positions of the first target vehicle 102, illustrated in the Figure 1 by a set of points C1, and successive positions of the second target vehicle 103, illustrated on the Figure 1 by a set of points C2. Periodically, the vehicle 101 considers a position of the set of points C1 and calculates the lateral distance D1 starting from this position and moving perpendicularly away from this position until intersecting the second shore line 12. The vehicle 101 also considers a position of the set of points C2 and calculates the distance D2 starting from this position and moving perpendicularly away from this position until intersecting the second shore line 12.

[0044] In a fourth operation, the vehicle 101 regulates its speed relative to the first target vehicle 102 if the first lateral distance D1 is less than the second lateral distance D2, and relative to the second target vehicle 103 if the first lateral distance D1 is greater than the second lateral distance D2. On the Figure 1 , the speed of the first vehicle 101 is regulated relative to the second target vehicle 103.

[0045] According to a particular and non-limiting exemplary embodiment, a line existence index is associated with each line detected on the ground of the traffic lanes, and the first, second, third and fourth lateral distances are obtained if the existence indices of the first and second edge lines are greater than a threshold. Otherwise, no change of the target vehicle is implemented.

[0046] According to a particular and non-limiting exemplary embodiment, the line existence index is a value between 0 and 1, the value 0 indicating that the detected line cannot be trusted and the value 1 indicating that the line is reliable.

[0047] Alternatively, intermediate values ​​between 0 and 1 indicate a degree of reliability of a line. A threshold can be used to indicate that the line is reliable if its existence index exceeds this threshold.

[0048] [ Fig. 2 ] schematically illustrates a device 2 configured to regulate the speed of a vehicle 101 from a target vehicle of the road environment of the Figure 1 , according to a particular and non-limiting exemplary embodiment of the present invention.

[0049] Device 2 is embedded in vehicle 101.

[0050] Device 2 is for example configured to implement the operations described with regard to the Figure 1and / or steps of the method described with regard to the Figure 3. Examples of such a device 2 include, but are not limited to, on-board electronic equipment such as a vehicle on-board computer, an electronic calculator such as an ECU (“Electronic Control Unit”), a smartphone, a tablet, a laptop. The elements of the device 2, individually or in combination, may be integrated into a single integrated circuit, into several integrated circuits, and / or into discrete components. The device 2 may be implemented in the form of electronic circuits or software (or computer) modules or even a combination of electronic circuits and software modules. According to various particular embodiments, the device 2 is communicatively coupled with other similar devices or systems, for example via a communication bus or through dedicated input / output ports.

[0051] The device 2 comprises one (or more) processor(s) 20 configured to execute instructions for carrying out the steps of the method and / or for executing the instructions of the software(s) embedded in the device 2. The processor 20 may include integrated memory, an input / output interface, and various circuits known to those skilled in the art. The device 2 further comprises at least one memory 21 corresponding for example to a volatile and / or non-volatile memory and / or comprises a memory storage device which may comprise volatile and / or non-volatile memory, such as EEPROM, ROM, PROM, RAM, DRAM, SRAM, flash, magnetic or optical disk.

[0052] The computer code of the embedded software(s) comprising the instructions to be loaded and executed by the processor is for example stored in the first memory 21.

[0053] According to a particular and non-limiting embodiment, the device 2 comprises a block 22 of interface elements for communicating with external devices, for example a remote server or the “cloud”, on-board sensors, devices such as radar or camera. The interface elements of the block 22 comprise one or more of the following interfaces: RF radio frequency interface, for example Bluetooth ® or Wi-Fi ®, LTE (Long-Term Evolution), LTE-Advanced; USB interface (Universal Serial Bus); HDMI interface (High Definition Multimedia Interface); LIN interface (Local Interconnect Network).

[0054] According to another particular embodiment, the device 2 comprises a communication interface 23 which makes it possible to establish communication with other devices (such as other computers of the on-board system when the device 2 corresponds to a computer of the on-board system) via a communication channel 24. The communication interface 23 corresponds for example to a transmitter configured to transmit and receive information and / or data via the communication channel 24. The communication interface 23 corresponds for example to a wired network of the CAN (Controller Area Network), CAN FD (Controller Area Network Flexible Data-Rate), FlexRay or Ethernet type.

[0055] According to an additional particular embodiment, the device 2 can provide output signals to one or more external devices, such as a display screen, one or more speakers and / or other peripherals via respectively output interfaces not shown.

[0056] [ Fig. 3 ] illustrates a flowchart of the different stages of a method for regulating the speed of a vehicle from a target vehicle in the road environment of the Figure 1 , according to a particular and non-limiting exemplary embodiment of the present invention.

[0057] The method is for example implemented by a device 2 on board the vehicle 101.

[0058] In a first step 31, a change of traffic lane is detected, moving from the first traffic lane 10, on which it is traveling, to the second traffic lane 11, on which it will travel when the change of traffic lane is completed.

[0059] In a second step 32, a first target vehicle 102 is detected, traveling in the first traffic lane 10 and a second target vehicle 103, traveling in the second traffic lane 11.

[0060] In a third step 33, a first lateral distance D1 is obtained between the first target vehicle 102 and the second shore line 12, and a second lateral distance D2 between the second target vehicle 103 and the second shore line 12.

[0061] In a fourth step 34, the speed of the vehicle 101 is regulated relative to the first target vehicle 102 if the first lateral distance D1 is less than the second lateral distance D2, and relative to the second target vehicle 103 if the first lateral distance D1 is greater than the second lateral distance D2.

[0062] Of course, the present invention is not limited to the exemplary embodiments described above but extends to a method for regulating the speed of a vehicle from a target vehicle which would include secondary steps without thereby departing from the scope of the present invention. The same would apply to a device configured for implementing such a method.

[0063] The invention also relates to a vehicle, for example an automobile or more generally a motor vehicle, comprising the device 2 of the Figure 2 .

Claims

1. A method for regulating the speed of a vehicle from a target vehicle, said method being implemented by at least one processor, said method comprising the following steps: - detection (31) of a change in the vehicle's lane of traffic from a first lane of traffic, on which the vehicle travels, to a second lane of traffic, on which the vehicle will travel when the lane change is completed, the second lane of traffic being delimited by a shoreline and a separation line; - detection (32) of a first target vehicle travelling in the first lane of traffic and of a second target vehicle travelling in the second lane; characterized in that it comprises the following steps: - obtaining (33) a first lateral distance between the first target vehicle and the shoreline and a second lateral distance between the second target vehicle and the shoreline; - the speed of the vehicle being then regulated (34) in relation to the first target vehicle if the first lateral distance is less than the second lateral distance, and the second target vehicle if the first lateral distance is greater than the second lateral distance.

2. A method according to claim 1, wherein the first lane of traffic being bounded by a riveline and the dividing line, the change of traffic lane is detected by comparing the lateral distances of the vehicle to the rivelines of the first and second lanes.

3. A method according to one of the preceding claims, wherein a riveting line is represented by a polynomial.

4. A method according to claim 3, wherein the edge line of the first lane of traffic is represented by a polynomial of degree 3 having a constant value equal to a third lateral distance between the vehicle and the edge line of the first lane of traffic, and the edge line of the second lane of traffic is represented by a polynomial of degree 3 of which a constant value is equal to a fourth lateral distance between the vehicle and the edge line of the second lane of traffic.

5. A method according to claim 4, wherein an indication of the existence of a line being associated with each line marked on the floor of the traffic lanes, the first, second, third and fourth distances are obtained if the indices of the existence of the edge lines of the first and second traffic lanes are greater than a threshold.

6. A computer program with instructions for carrying out the method according to any one of the preceding claims, when such instructions are executed by a processor.

7. A computer-readable recording medium on which a computer program is stored including instructions for performing the process steps according to any of claims 1 to 5.

8. A device (2) for assisting the driver of a vehicle traveling on a traffic lane, said device (2) comprising a memory (21) associated with at least one processor (20) configured for carrying out the process steps according to any one of claims 1 to 5.

9. A vehicle (10) comprising the device (2) according to claim 8.