WO2024018127A1

WO2024018127A1 - Method for controlling a trajectory of a motor vehicle changing lanes

Info

Publication number: WO2024018127A1
Application number: PCT/FR2023/050839
Authority: WO
Inventors: Zoubida LAHLOU; Hamza El Hanbali; Yassine Et-Thaqfy
Original assignee: Stellantis Auto Sas
Priority date: 2022-07-18
Filing date: 2023-06-12
Publication date: 2024-01-25
Also published as: FR3137888B1; FR3137888A1

Abstract

The invention relates to a method for controlling a state machine defining the state of a state variable (ME) descriptive of a state of a motor vehicle (10) changing lanes. The control method is characterised in that it is possible to force the state variable (ME) into a third state (3) that is expected once the vehicle has changed lanes if, within a given time period, the detection system produces unexpected variations in the state variable (ME) between a second state (2) and a fourth state (4), or vice versa.

Description

Title of the invention: Method for controlling the trajectory of a motor vehicle when changing lanes

The present invention claims priority from French application 2207332 filed on 07/18/2022, the content of which (text, drawings and claims) is herein incorporated by reference.

[1] the technical context of the present invention is that of the methods and devices for controlling a lateral guidance system of a motor vehicle. More particularly, the invention relates to a method for controlling the trajectory of a motor vehicle when changing lanes.

[2] Some contemporary vehicles are equipped with functions or system(s) or driving assistance, known as ADAS, an acronym for “Advanced Driver-Assistance System” and meaning “Advanced Driving Assistance System”.

[3] Among these systems, we know the semi-automatic lane change systems, referred to in the literature by the acronym SALC, an English acronym meaning “Semi Active Lateral Control”.

[4] The primary function of these SALC systems is to assist the driver of the motor vehicle when he wishes to change lanes of traffic on a road area. Upon detection of the activation of the indicators on one side of the vehicle to indicate its intention to change lanes from a current traffic lane - called the initial lane - to a target traffic lane - called the destination lane - on the side where the indicators have been activated by the driver, the SALC system operates the lane change after having carried out some checks, in particular on the lines that it detects on the road area concerned.

[5] During these checks, the SALC system updates the state variable which reflects the relative position of the motor vehicle in relation to the initial lane of traffic in the road area. In a known manner, the state variable can take the following states:

[6] - a first state representative of the motor vehicle positioned in the initial lane of the road zone; [7] - a second state representative of the motor vehicle crossing a separation line of the initial lane of the road zone, the crossing of the separation line being detected by a sensor of the detection system located at the level of a front wheel left of said motor vehicle;

[8] - a third being representative of a reference frame of the motor vehicle oriented in the direction of a destination lane of the road zone adjacent to the initial lane

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[9] - a fourth state representative of the motor vehicle crossing the separation line of the initial lane of the road zone, the crossing of the separation line being detected by a sensor of the detection system located at the level of a front wheel right of said motor vehicle.

[10] In a known manner, a state machine controls the updating of this state variable in order to account for the relative position of the motor vehicle in the road area, and more particularly on the traffic lanes.

[11] Thus, in normal operation, when the motor vehicle traveling in the initial lane makes a lane change towards the destination lane, the state variable successively takes the following values:

[12] - the state variable is first defined in its first state, corresponding to the situation in which the motor vehicle is driving in the initial lane;

[13] - then, the state variable is defined in its second state or its fourth state, depending on whether the motor vehicle changes lanes respectively to the left or to the right;

[14] - then, the state variable is defined in its third state, illustrating the reorientation of the motor vehicle towards the destination lane;

[15] - finally, when the motor vehicle has arrived in the destination lane, the state variable is defined again in its first state.

[16] This cycle thus corresponds to the nominal operation of the state machine for a normal change of lane.

[17] The checks carried out by the SALC system make it possible to verify that the lane change and its description through the state variable and the state machine are compliant. In particular, some of these controls aim to control the duration of the lane change operation. Thus, a first check verifies that all operations relating to lane changes do not exceed 12 seconds. Even more particularly, a second check verifies that the duration separating the crossing of the traffic lane separation line until the end of the lane change operation does not exceed 5 seconds.

[18] However, it sometimes happens that problems detecting the relative position of the motor vehicle in relation to the traffic lanes lead to poor updating of the state variable, subsequently leading to a blocking of the state machine and, in fact, some of the durations monitored by the SALC system are exceeded.

[19] The object of the present invention is to propose a new method of trajectory control during a lane change in order to respond at least largely to the previous problems and to also lead to other advantages.

[20] Another aim of the invention is to avoid blocking of the state machine resulting from a detection fault rather than from an error in the lane change maneuver.

[21] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a method of controlling a trajectory of a motor vehicle during a lane change on a road area, a relative position of the motor vehicle on the road area being detected by a detection system comprising at least one sensor configured to detect a relative position of the motor vehicle in a lane of the road scene, the method comprising updating, during the change of lane, of a state variable representative of a relative position of the motor vehicle with respect to an initial lane of the road zone, the state variable being able to take the following states:

[22] - a first state representative of the motor vehicle positioned in the initial lane of the road zone;

[23] - a second state representative of the motor vehicle crossing a separation line of the initial lane of the road zone, the crossing of the separation line being detected by a sensor of the detection system located at the level of a front wheel left of said motor vehicle; [24] - a third being representative of a reference frame of the motor vehicle oriented in the direction of a destination lane of the road zone adjacent to the initial lane;

[25] - a fourth state representative of the motor vehicle crossing the separation line of the initial lane of the road zone, the crossing of the separation line being detected by a sensor of the detection system located at a front wheel right of said motor vehicle.

[26] According to the invention in accordance with its first aspect, if during the lane change of the motor vehicle, the state variable passes from the second state to the fourth state, in one direction or the other, within a period of transit less than a predetermined calibration duration, then the state variable is forced to its third state at the end of the calibration duration.

[27] In the context of the present invention, the lane change of the motor vehicle consists of a lateral movement, to the left or to the right, of the motor vehicle from the initial lane towards the destination lane. The lane change can be carried out manually by the driver of the motor vehicle or automatically by said motor vehicle itself, controlled by an autonomous or semi-autonomous driving mode.

[28] In the context of the present invention, the state variable is updated during the lane change operation, based on the position indications of the motor vehicle on the road area provided by the detection system.

[29] In the context of the present invention, the detection system is configured to make it possible to determine the relative position of a part of the motor vehicle with respect to certain elements of the road area, such as for example a traffic lane - initial or destination - or a separation line, continuous or discontinuous, separating two adjacent traffic lanes.

[30] In the context of the present invention, the at least one sensor of the detection system is chosen from a camera sensitive to visible light and/or a camera sensitive to infrared light and/or a radar and/or a laser radar and/or an ultrasonic sensor. [31] In the context of the present invention, if during the lane change of the motor vehicle, the state variable passes - directly or indirectly - from the second state to the fourth state, in one direction or the other, in a transit delay less than a predetermined calibration duration, then the state variable is forced to its third state at the end of the calibration duration. Thus, in the context of the invention, the condition for the state variable to be forced to its third state includes the passage, direct or indirect, from the second state to the fourth state, reflecting a change of lane to the left, or the passage, direct or indirect from the fourth state to the second state, reflecting a change of lane to the right.

[32] In the context of the present invention, we understand by “forced” that the state variable is defined in its third state regardless of the previous state of said state variable taken just before the expiration of the delay of transit.

[33] Thus, the invention already allows the detection of an aberrant cycle of the states of the state variable from the second state to the fourth state or from the fourth state to the second state, resulting from a situation impossible to control. realize according to which the front wheels of the motor vehicle would cross the lane dividing line without the motor vehicle being oriented towards the destination lane. Subsequently, the control method in accordance with the first aspect of the invention makes it possible to restore normal operation of the state machine by forcing an update of the state variable which makes it possible not to block the operation of the state machine. this or trigger an unwanted alert or error message in such a situation.

[34] In other words, if the detection system detects a double crossing of the dividing line, successively by the right front wheel and by the left front wheel, in any of the directions, within the time limit transit itself less than the calibration duration, then the control method constrains the state variable in its third state in order to allow a state machine controlling the smooth progress of the lane change to continue to operate without be misled.

[35] The control method according to the first aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements which can be taken alone or in combination:

[36] - during the transit delay, the state variable passes successively from the second state to the first state then to the fourth state. Alternatively, during the transit delay, the state variable passes successively from the fourth state to the first state then to the second state. These two cycles of state variables correspond to undesired and non-representative operation of the lane change made by the motor vehicle, as described previously;

[37] - the transit delay countdown begins when the state variable moves to its first state. In particular, the transit delay begins at the time of a falling edge of the state variable during which the state variable passes from its second state or its fourth state to its first state. In the context of the invention, the transit time is counted by a clock on board the motor vehicle;

[38] - generally speaking, the calibration time is less than 1 second. This calibration duration makes it possible to avoid maintaining the state variable in this configuration for too long in order, ultimately, to allow the state machine to complete the cycle corresponding to the lane change within the expected and previously mentioned deadlines;

[39] - preferably, the calibration duration is less than 500 ms. Particularly advantageously, the calibration duration is between 300 ms and 350 ms;

[40] - the state variable is forced to its third state at the end of the calibration duration if, during said calibration duration, the lane change is detected by the detection system. In the context of the invention the change of lane is detected by the detection system, a second state variable being updated to translate the change of the lane, from the initial lane to the destination lane. Thus, in this embodiment, the state variable is forced to its third state if, within the transit delay, in addition to the conditions mentioned previously, the detection system detects a variation in the second state variable reflecting the change of lane. [41] According to a second aspect of the invention, a detection system is proposed comprising (i) at least one sensor located at the front wheels of a motor vehicle in order to be able to detect a crossing of a lane separation line of a road zone, and (ii) a control unit configured to implement the control method according to the first aspect of the invention or according to any of its improvements.

[42] As mentioned previously, the at least one sensor of the detection system conforming to the second aspect of the invention is chosen from a camera sensitive to visible light and/or a camera sensitive to infrared light and/or a radar and/or a laser radar and/or an ultrasonic sensor.

[43] According to a third aspect of the invention, a motor vehicle is proposed comprising a detection system conforming to the second aspect of the invention.

[44] Various embodiments of the invention are planned, integrating, according to all of their possible combinations, the different optional characteristics exposed here.

[45] Other characteristics and advantages of the invention will appear further through the description which follows on the one hand, and several examples of embodiment given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand , on which ones :

[46] [Fig.1] illustrates a flowchart of a first lane change situation of a motor vehicle;

[47] [Fig.2] illustrates a flowchart of a second lane change situation of a motor vehicle;

[48] [Fig.3] illustrates a timing diagram illustrating the updating of a state variable representative of the lane change according to the control method according to the invention.

[49] Of course, the characteristics, variants and different embodiments of the invention can be associated with each other, in various combinations, to the extent that they are not incompatible or exclusive of each other. In particular, it will be possible to imagine variants of the invention comprising only a selection of characteristics described subsequently. in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention compared to the prior art.

[50] In particular, all the variants and all the embodiments described can be combined with each other if nothing opposes this combination on a technical level.

[51] In the figures, elements common to several figures retain the same reference.

[52] With reference to FIGURES 1 and 2, the context of the present invention and that of changing the lane of a motor vehicle 10 from an initial lane VI to a destination lane VD are presented. In FIGURES 1 and 2, several situations are detailed during a lane change operation. Below each situation, a chronogram reports the state variable ME controlled by the state machine and which reports the state of the motor vehicle 10 during the lane change operation. Thus, the state variable ME can take the following states:

[53] - in the first situation S1 accounting for the motor vehicle 10 positioned in the initial lane VI of the road zone ZR, the state variable ME is defined by the state machine in its first state 1;

[54] - in the second situation S2 reporting the motor vehicle 10 crossing a separation line of the initial lane VI of the road zone ZR, the crossing of the separation line being detected by a sensor of the detection system located at level of a front wheel of said motor vehicle 10. Consequently, as visible on the chronogram, the state variable ME is defined by the state machine in its second state 2 representative of the crossing of the separation line by the front wheel left, as visible in FIGURE 1, or in its fourth state 4 representative of the crossing of the separation line by the right front wheel, as visible in FIGURE 2;

[55] - in the third situation S3 accounting for the motor vehicle 10 oriented in the direction of a destination lane VD of the road zone ZR adjacent to the initial lane VI, the state variable ME is defined by the machine states to its third state 3. [56] A DMmax maneuvering delay

[57] is designed to be able to carry out this lane change operation. The DMmax maneuvering time

[58] corresponds to the time taken by the motor vehicle 10 to complete the lane change operation from the moment when the crossing of the separation line by the front wheel was detected. In the context of the invention, it is expected that the maneuvering time DMmax

[59] is less than or equal to 5 seconds.

[60] With reference to FIGURE 3, the clever contribution of the control method according to the invention is shown. In this case, if the state machine, put into error for example by a faulty operation of the sensors of the detection system, first configures the state variable ME in its fourth state 4 then, in a time interval - said transit delay DT - less than a calibration duration, configures said state variable ME in its second state 2, then, at the end of the transit delay DT, the state variable ME is configured in its third state 3.

[61] This configuration is done as quickly as possible after establishing the state variable ME in its second state 2, for example in less than 10 ms, or even less than 1 ms.

[62] Of course, FIGURE 3 representing the variation of the state variable ME during a lane change operation to the left, the invention addresses mutatis mutandis an analogous cycle for a lane change to the right.

[63] In this case, if the state machine, put into error for example by a faulty operation of the sensors of the detection system, first configures the state variable ME in its second state 2 then, in an interval of time - called transit delay DT - less than a calibration duration, configures said state variable ME in its fourth state 4, then, at the end of the transit delay DT, the state variable ME is configured in its third state 3.

[64] This configuration is done as quickly as possible after establishing the state variable ME in its second state 2, for example in less than 10 ms, or even less than 1 ms. [65] The state variable ME configured in its third state 3 is thus maintained in this third state 3 until the expiry of at least the maneuvering delay DMmax

[66] for the lane change operation considered.

[67] Cleverly, the forcing of the state variable ME into its third state 3 is subject to the detection of a line change variable LE representative of the crossing of the separation line by the motor vehicle 10, here in its second L2 channel.

[68] The invention thus makes it possible to restore a state of the state variable ME consistent with reality at the end of a lane change operation and without faulting or erroring the state machine, i.e. that is to say by allowing it to continue to operate after the lane change operation and not to trigger an error signal at the end of the regulatory deadlines for execution of the change operation track, as described previously.

[69] In summary, the invention relates to a method for controlling a state machine defining the state of a state variable ME descriptive of a state of a motor vehicle 10 operating a lane change. Cleverly, the control method makes it possible to force the state variable ME into a third state 3 expected at the end of the lane change if, in a given time interval, the detection system leads to unexpected variations in the state variable ME between a second state 2 and a fourth state 4, or vice versa.

[70] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In particular, the different characteristics, shapes, variants and embodiments of the invention can be associated with each other in various combinations to the extent that they are not incompatible or exclusive of each other. In particular, all the variants and embodiments described above can be combined with each other.

Claims

[Claim 1] Method for controlling a trajectory of a motor vehicle (10) during a lane change on a road zone (ZR), a relative position of the motor vehicle (10) on the road zone ( ZR) being detected by a detection system comprising at least one sensor configured to detect a relative position of the motor vehicle (10) in a lane of the road scene, the method comprising updating, during the lane change, 'a state variable (ME) representative of a relative position of the motor vehicle (10) relative to an initial lane (VI) of the road zone (ZR), the state variable (ME) being able to take following states:

- a first state (1) representative of the motor vehicle (10) positioned in the initial lane (VI) of the road zone (ZR);

- a second state (2) representative of the motor vehicle (10) crossing a separation line of the initial lane (VI) of the road zone (ZR), the crossing of the separation line being detected by a sensor of the system detection located at a left front wheel of said motor vehicle (10);

- a third being representative of a reference frame of the motor vehicle (10) oriented in the direction of a destination lane (VD) of the road zone (ZR) adjacent to the initial lane (VI);

- a fourth state (4) representative of the motor vehicle (10) crossing the separation line of the initial lane (VI) of the road zone (ZR), the crossing of the separation line being detected by a sensor of the system detection located at a right front wheel of said motor vehicle (10); characterized in that, if during the lane change of the motor vehicle (10), the state variable (ME) passes from the second state (2) to the fourth state (4), in one direction or the other, in a transit delay (DT) less than a predetermined calibration duration, then the state variable (ME) is forced to its third state (3) at the end of the calibration duration. [Claim 2] Control method according to claim 1, in which, during the transit delay (DT), the state variable (ME) successively passes from the second state

(2) to the first state (1) then to the fourth state (4).

[Claim 3] Control method according to claim 1, in which, during the transit delay (DT), the state variable (ME) passes successively from the fourth state (4) to the first state (1) then to the second state (2).

[Claim 4] Control method according to any one of the preceding claims, in which the counting of the transit delay (DT) begins when the state variable (ME) transitions to its first state (1).

[Claim 5] Control method according to the preceding claim, in which the calibration duration is less than 1 second.

[Claim 6] Control method according to the preceding claim, in which the calibration duration is between 300 ms and 350 ms.

[Claim 7] Control method according to any one of the preceding claims, in which the state variable (ME) is forced to its third state (3) at the end of the calibration duration if, during said duration calibration, the lane change is detected by the detection system.

[Claim 8] Detection system comprising:

- at least one sensor located at the front wheels of a motor vehicle (10) in order to be able to detect a crossing of a lane separation line (VD, VI) of a road zone (ZR);

- a control unit configured to implement the control method according to any one of the preceding claims.

[Claim 9] Motor vehicle (10) comprising a detection system according to the preceding claim, i