CN116552519A

CN116552519A - Vehicle motion control method and apparatus

Info

Publication number: CN116552519A
Application number: CN202210111028.7A
Authority: CN
Inventors: 吴鹏; 金颖
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2022-01-29
Filing date: 2022-01-29
Publication date: 2023-08-08

Abstract

The invention relates to a vehicle motion control method, comprising the following steps: receiving lane line information of a lane on which the vehicle runs, wherein the lane line information comprises a first lane line length and a second lane line length of the lane on which the vehicle runs; determining a maximum allowable value c2_max and a minimum allowable value c2_min of the curvature of the lane center line at the current moment when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is smaller than a first threshold value and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value; and updating a curvature c2 of the lane center line at the current time based on the maximum allowable value c2_max and the minimum allowable value c2_min, so that the vehicle motion controller can perform path planning and control on the own vehicle based on the updated curvature c2_update of the lane center line. The invention also relates to a vehicle motion control device, a computer program product and a vehicle.

Description

Vehicle motion control method and apparatus

Technical Field

The present invention relates to the field of vehicle control, and more particularly to a vehicle motion control method and apparatus, a computer program product, and a vehicle.

Background

With the development of intellectualization of vehicles, more and more vehicles are equipped with intelligent driving functions such as TJA (traffic jam assist), ICA (high-speed intelligent navigation), LKS (lane keeping), and the like. In using these functions, various intelligent controls (including but not limited to chassis domain control) of the vehicle are required in conjunction with information obtained by the sensors.

However, in some situations (e.g., where the host vehicle is very close to the lead vehicle during a traffic jam or the vehicle is traveling uphill), the lane line length detected by the sensor (e.g., an onboard camera) may be short, which may easily result in a jump in the curvature of the determined lane center line. This is disadvantageous for lateral function control, in particular for steering performance.

Disclosure of Invention

According to an aspect of the present invention, there is provided a vehicle motion control method including: receiving lane line information of a lane on which the vehicle runs, wherein the lane line information comprises a first lane line length and a second lane line length of the lane on which the vehicle runs; determining a maximum allowable value c2_max and a minimum allowable value c2_min of the curvature of the lane center line at the current moment when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is smaller than a first threshold value and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value; and updating a curvature c2 of the lane center line at the current time based on the maximum allowable value c2_max and the minimum allowable value c2_min, so that the vehicle motion controller can perform path planning and control on the own vehicle based on the updated curvature c2_update of the lane center line.

Additionally or alternatively to the above, in the above method, receiving lane line information of a lane on which the host vehicle is traveling includes: signals relating to left and right lane lines of a driven lane are received from a video camera sensor.

Additionally or alternatively to the above, in the above method, the relevant intelligent driving function is a traffic congestion assist function TJA or a lane keeping function LKS.

Additionally or alternatively to the above, in the above method, the first threshold is 15m and the second threshold is 0.0015.

Additionally or alternatively to the above, in the above method, when the relevant intelligent driving function is activated, either one of the first lane line length and the second lane line length is smaller than a first threshold value, and the curvature c2 of the lane center line at the current time is smaller than a second threshold value, determining the maximum allowable value c2_max and the minimum allowable value c2_min of the lane center line curvature at the current time includes determining the maximum allowable value c2_max and the minimum allowable value c2_min of the lane center line curvature at the current time as follows:

c2_max=c2_k1+ calibration step size is cycle time;

c2 min=c2_k1-calibration step size-cycle time,

wherein c2_k1 represents the curvature of the lane center line of the previous cycle, and the calibration step length is a constant.

Additionally or alternatively to the above, in the above method, updating the curvature c2 of the lane center line at the current time based on the maximum allowable value c2_max and the minimum allowable value c2_min includes determining an updated curvature c2_update of the lane center line according to the following formula:

c2_update = max (c2_Min, min (c2, c2_Max))。

additionally or alternatively to the above, the method further comprises: and when the related intelligent driving function is activated, the average value of the first lane line length and the second lane line length is smaller than a third threshold value, the current road gradient is larger than a calibration value, and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value, adjusting the target steering torque according to the current vehicle speed and the average value of the first lane line length and the second lane line length.

Additionally or alternatively to the above, in the above method, adjusting the target steering torque according to the current vehicle speed and an average value of the first lane line length and the second lane line length includes: obtaining an attenuation factor by looking up a table based on the current vehicle speed and the average value; and adjusting the target steering torque according to the attenuation factor.

According to another aspect of the present invention, there is provided a vehicle motion control apparatus including: the receiving device is used for receiving lane line information of a lane where the vehicle runs, wherein the lane line information comprises a first lane line length and a second lane line length of the lane where the vehicle runs; determining means for determining a maximum allowable value c2_max and a minimum allowable value c2_min of the curvature of the lane center line at the present moment when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is smaller than a first threshold value and the curvature c2 of the lane center line at the present moment is smaller than a second threshold value; and updating means for updating the curvature c2 of the lane center line at the present time based on the maximum allowable value c2_max and the minimum allowable value c2_min so that the vehicle motion controller can perform path planning and control of the own vehicle based on the updated curvature c2_update of the lane center line.

Additionally or alternatively to the above, in the above apparatus, the receiving means is configured to: signals relating to left and right lane lines of a driven lane are received from a video camera sensor.

Additionally or alternatively to the above, in the above apparatus, the determining means is configured to determine a maximum allowable value c2_max and a minimum allowable value c2_min of the lane center line curvature at the present time as follows:

c2_max=c2_k1+ calibration step size is cycle time;

c2 min=c2_k1-calibration step size-cycle time,

Additionally or alternatively to the above, in the above apparatus, the updating means is configured to determine the updated curvature c2_update of the lane center line according to the following formula:

c2_update = max (c2_Min, min (c2, c2_Max))。

additionally or alternatively to the above, the apparatus may further include: and the torque adjusting device is used for adjusting the target steering torque according to the current vehicle speed and the average value of the first lane line length and the second lane line length when the related intelligent driving function is activated, the average value of the first lane line length and the second lane line length is smaller than a third threshold value, the current road gradient is larger than a calibration value and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value.

According to yet another aspect of the invention, there is provided a computer storage medium comprising instructions which, when executed, perform a method as described above.

According to a further aspect of the invention there is provided a computer program product comprising a computer program which, when executed by a processor, implements a method as described above.

According to a further aspect of the invention there is provided a vehicle comprising an apparatus as hereinbefore described.

The vehicle control scheme of the embodiment of the invention determines a maximum allowable value c2_max and a minimum allowable value c2_min of the curvature of the lane center line at the current moment when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is smaller than a first threshold value and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value; and updating the curvature c2 of the lane center line at the current moment based on the maximum allowable value c2_Max and the minimum allowable value c2_Min, so that the vehicle motion controller can perform path planning and control on the vehicle based on the updated curvature c2_update of the lane center line, thereby avoiding steering jitter caused by curvature jump and/or shorter lane line length, and greatly improving the performance and comfort of the vehicle.

Drawings

The above and other objects and advantages of the present invention will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawings, in which identical or similar elements are designated by the same reference numerals.

FIG. 1 illustrates a flow diagram of a vehicle motion control method according to one embodiment of the invention;

fig. 2 shows a schematic structural view of a vehicle motion control apparatus according to an embodiment of the present invention; and

fig. 3 shows a flow chart of a vehicle motion control method according to an embodiment of the invention.

Detailed Description

Hereinafter, a vehicle control scheme according to exemplary embodiments of the invention will be described in detail with reference to the accompanying drawings.

Fig. 1 shows a flow diagram of a vehicle motion control method 1000 according to one embodiment of the invention. As shown in fig. 1, the vehicle motion control method 1000 includes the steps of:

in step S110, lane line information of a lane on which the host vehicle is traveling is received, the lane line information including a first lane line length and a second lane line length of the lane on which the host vehicle is traveling;

in step S120, when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is smaller than a first threshold value, and the curvature c2 of the lane center line at the current time is smaller than a second threshold value, determining a maximum allowable value c2_max and a minimum allowable value c2_min of the lane center line curvature at the current time; and

in step S130, the curvature c2 of the lane center line at the current time is updated based on the maximum allowable value c2_max and the minimum allowable value c2_min, so that the vehicle motion controller can perform path planning and control for the own vehicle based on the updated curvature c2_update of the lane center line.

Lane detection is a central task in modern assistance and autopilot systems, which can locate the exact shape of each lane in a traffic scene. In particular, lane detection is more critical to further downstream trajectory planning tasks to maintain proper positioning of the vehicle with the road lane as it turns in complex road scenarios. In practical applications, lane detection is very challenging considering that lanes are of varying shapes and sizes and are likely to be obscured by other traffic objects.

The term "lane line information" means lane line information related to a current driving lane of the host vehicle, including a first lane line length and a second lane line length. Here, the left and right lane lines are distinguished by expressions such as "first" and "second". In one embodiment, the first lane line length represents a detected left lane line length and the second lane line length is a detected right lane line length. In another embodiment, the first lane line length is a detected right lane line length and the second lane line length is a detected left lane line length. In one or more embodiments, the lane line information may include a curvature of the first lane line and a curvature of the second lane line in addition to the lane line length.

In one embodiment, step S110 includes: signals relating to left and right lane lines of a driven lane are received from a video camera sensor. For example, the video camera sensor is MPC, wherein the MPC multifunctional camera is arranged above a vehicle rearview mirror, so that the condition of a road ahead can be clearly monitored. In particular, the MPC combines a multi-path recognition algorithm and artificial intelligence for target recognition, so that the result of sensing the surrounding environment is more accurate and reliable, and the road traffic safety is improved.

In the context of the present invention, the term "relevant intelligent driving function" may be any intelligent driving function that utilizes lane line information, including, but not limited to, a traffic congestion assistance function TJA or a lane keeping function LKS.

In one embodiment, the first threshold value compared to the first lane line length and the second lane line length is 15m and the second threshold value compared to the curvature c2 of the lane center line is 0.0015.

The term "lane centerline", as the name implies, refers to the centerline of the current lane, which is commonly used in assisted or unmanned systems for vehicle control procedures such as vehicle path planning. It should be noted that this center line does not actually exist in the actual road, and cannot be obtained directly by detection of the sensor. In one or more embodiments, the geometric center line of the lane lines on both sides of the lane (i.e., the left and right boundary lines of the lane) may be directly taken as the lane center line.

The lane centerline may be updated on a periodic basis. In one embodiment, in the host vehicle rear axis coordinate system (where the x-axis points in the vehicle forward direction (i.e., up positive and down negative),the y-axis points sideways (left positive right negative) of the vehicle, and the updated lane center line is represented by the following third-order polynomial: y is _predict (x)=c0+c1*x+1/2*c2 _predict *x ² +1/6*c3*x ³ Wherein c0 is the lateral offset between the host vehicle and the lane centerline, c1 is the yaw offset relative to the lane centerline, c2 _predict Is the curvature of the updated lane centerline, and c3 is the curvature change.

In one embodiment, step S120 includes: the maximum allowable value c2_max and the minimum allowable value c2_min of the lane center line curvature at the present time are determined as follows:

c2_max=c2_k1+ calibration step size is cycle time;

c2 min=c2_k1-calibration step size-cycle time,

where c2_k1 represents the curvature of the lane centerline of the previous cycle, and the calibration step is an empirical constant (e.g., calibrated according to real vehicles).

In one embodiment, step S130 includes determining the updated curvature c2_update of the lane centerline according to the following formula:

c2_update = max (c2_Min, min (c2, c2_Max))。

that is, the lane center line curvature c2 at the present time is adjusted (or framed) according to the calculated maximum allowable value c2_max and minimum allowable value c2_min of the lane center line curvature at the present time, thereby obtaining the updated lane center line curvature c2_update. Specifically, the smaller value of the lane center line curvature c2 at the present time and the maximum allowable value c2_max of the lane center line curvature at the present time is taken first, and then the larger value of the smaller value and the minimum allowable value c2_min of the lane center line curvature at the present time is taken. In this way, jumps in curvature of the lane center line can be effectively avoided.

The updated lane centerline is used for subsequent vehicle control (e.g., chassis domain control). In one embodiment, the lane centerline may be used as a reference trajectory for vehicle path planning, which may be used for lateral torque request planning of the vehicle.

Although not shown in fig. 1, in one embodiment, the method 1000 further includes: and when the related intelligent driving function is activated, the average value of the first lane line length and the second lane line length is smaller than a third threshold value, the current road gradient is larger than a calibration value, and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value, adjusting the target steering torque according to the current vehicle speed and the average value of the first lane line length and the second lane line length.

Specifically, a table look-up may be performed based on the current vehicle speed and the average value to obtain an attenuation factor; and then adjusts the target steering torque according to the attenuation factor.

For example, assuming that the target steering torque before adjustment is T1 and the target steering torque after adjustment is T2, then:

T2 = T1 * factor；

where factor represents an attenuation factor, which can be determined from the current vehicle speed vx (longitudinal speed) and the average of the left and right lane line lengths. In one embodiment, the relationship between the factor and the current vehicle speed vx (longitudinal speed) and the average of the left and right lane line lengths can be found in table 1 below.

Table 1: attenuation factor table

In addition, those skilled in the art will readily appreciate that the vehicle motion control methods provided by one or more of the above-described embodiments of the present invention may be implemented by a computer program. For example, the computer program is embodied in a computer program product that when executed by a processor implements the vehicle motion control method of one or more embodiments of the invention. For another example, when a computer storage medium (e.g., a USB flash disk) storing the computer program is connected to a computer, the computer program is run to perform the vehicle motion control method of one or more embodiments of the present invention.

Referring to fig. 2, fig. 2 shows a schematic configuration of a vehicle motion control apparatus 2000 according to an embodiment of the present invention. As shown in fig. 2, the vehicle motion control apparatus 2000 includes: receiving means 210, determining means 220, and updating means 230; the receiving device 210 is configured to receive lane line information of a lane where the host vehicle travels, where the lane line information includes a first lane line length and a second lane line length of the lane where the host vehicle travels; the determining means 220 is configured to determine a maximum allowable value c2_max and a minimum allowable value c2_min of the curvature of the lane center line at the current time when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is smaller than a first threshold value and the curvature c2 of the lane center line at the current time is smaller than a second threshold value; and updating means 230 for updating the curvature c2 of the lane center line at the current time based on the maximum allowable value c2_max and the minimum allowable value c2_min, so that the vehicle motion controller can perform path planning and control for the own vehicle based on the updated curvature c2_update of the lane center line.

In one embodiment, the receiving device 210 is configured to receive signals from the video camera sensor related to left and right lane lines of the driven lane. For example, the video camera sensor is MPC, wherein the MPC multifunctional camera is arranged above a vehicle rearview mirror, so that the condition of a road ahead can be clearly monitored. In particular, the MPC combines a multi-path recognition algorithm and artificial intelligence for target recognition, so that the result of sensing the surrounding environment is more accurate and reliable, and the road traffic safety is improved.

The lane centerline may be updated on a periodic basis. In one embodiment, in the host vehicle rear axis coordinate system, where the x-axis points in the vehicle forward direction (i.e., up-positive-down-negative) and the y-axis points sideways (left-positive-right-negative), the updated lane centerline is represented by the following third-order polynomial: y is _predict (x)=c0+c1*x+1/2*c2 _predict *x ² +1/6*c3*x ³ Wherein c0 is the lateral offset between the host vehicle and the lane centerline, c1 is the yaw offset relative to the lane centerline, c2 _predict Is the curvature of the updated lane centerline, and c3 is the curvature change.

In one embodiment, the determining means 220 is configured to determine the maximum allowable value c2_max and the minimum allowable value c2_min of the lane center line curvature at the present moment according to the following formula:

c2_max=c2_k1+ calibration step size is cycle time;

c2 min=c2_k1-calibration step size-cycle time,

In one embodiment, the updating means 230 is configured to determine the updated curvature c2_update of the lane centerline according to the following formula:

c2_update = max (c2_Min, min (c2, c2_Max))。

that is, the updating means 230 adjusts (or frames) the lane center line curvature c2 at the present time according to the calculated maximum allowable value c2_max and minimum allowable value c2_min of the lane center line curvature at the present time, thereby obtaining an updated lane center line curvature c2_update. Specifically, the updating means 230 takes the smaller value of the lane center line curvature c2 at the present time and the maximum allowable value c2_max of the lane center line curvature at the present time, and then takes the larger value of the smaller value and the minimum allowable value c2_min of the lane center line curvature at the present time. In this way, jumps in curvature of the lane center line can be effectively avoided.

Although not shown in fig. 2, in one embodiment, the apparatus 2000 may further include: and the torque adjusting device is used for adjusting the target steering torque according to the current vehicle speed and the average value of the first lane line length and the second lane line length when the related intelligent driving function is activated, the average value of the first lane line length and the second lane line length is smaller than a third threshold value, the current road gradient is larger than a calibration value and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value.

Specifically, the torque adjustment device may look up a table based on the current vehicle speed and the average value to obtain an attenuation factor; and then adjusts the target steering torque according to the attenuation factor.

T2 = T1 * factor；

where factor represents an attenuation factor, which can be determined from the current vehicle speed vx (longitudinal speed) and the average of the left and right lane line lengths.

Referring to fig. 3, a flow chart of a vehicle motion control method according to one embodiment of the invention is shown. As shown in fig. 3, in step S310, the entire flow starts. Next, in step S315, it is determined whether the traffic congestion support function TJA or the lane keeping function LKS is on (active), and if so, the flow goes to step S320 and step S355, and if not, the flow goes to step S325. In step S320, it is determined whether any one of the left and right lane line lengths is smaller than a first threshold (e.g., 15 m) and the curvature c2 of the lane center line at the present time is smaller than a second threshold (e.g., 0.0015) is "true". If true, step S330 is performed, otherwise step S335 is performed. In step S335, the curvature c2 of the lane center line at the current time is continuously maintained (i.e., no update is required). In step S330, the maximum allowable value c2_max and the minimum allowable value c2_min of the lane center line curvature at the present time are determined as follows:

c2_max=c2_k1+ calibration step size is cycle time;

c2 min=c2_k1-calibration step size-cycle time,

wherein c2_k1 represents the curvature of the lane centerline of the previous cycle, the calibration step is an empirical value constant (e.g., calibrated according to real vehicles), and the updated curvature c2_update of the lane centerline is determined according to the following formula:

c2_update = max (c2_Min, min (c2, c2_Max))。

in step S340, the curvature is sent out (e.g., to a motion control module). In step S345, the motion control module performs corresponding control based on the received curvature. In step S350, a target rotational torque is issued.

In step S325, the target rotational torque is set to 0.

In step S355, it is determined whether or not the average value of the first lane line length and the second lane line length is smaller than the third threshold value, the absolute value of the current road gradient is larger than the calibration value, and (the absolute value of) the curvature of the lane center line at the current time c2 is smaller than the second threshold value is "true". If true, step S360 is performed, otherwise step S365 is performed.

In step S360, the target turning torque is adjusted according to the formula t2=t1, where T1 is the target turning torque before adjustment, T2 is the target turning torque after adjustment, and factor represents an attenuation factor, which can be determined according to the current vehicle speed vx (longitudinal speed) and the average value of the left and right lane line lengths.

In step S365, the original target rotational torque is continuously maintained (i.e., no adjustment is made).

Finally, in step 370, the entire flow is ended.

In summary, the vehicle control scheme of the embodiment of the present invention determines the maximum allowable value c2_max and the minimum allowable value c2_min of the lane center line curvature at the present time when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is smaller than the first threshold value and the curvature c2 of the lane center line at the present time is smaller than the second threshold value; and updating the curvature c2 of the lane center line at the current moment based on the maximum allowable value c2_Max and the minimum allowable value c2_Min, so that the vehicle motion controller can perform path planning and control on the vehicle based on the updated curvature c2_update of the lane center line, thereby avoiding steering jitter caused by curvature jump and/or shorter lane line length, and greatly improving the performance and comfort of the vehicle.

While the above description describes only some of the embodiments of the present invention, those of ordinary skill in the art will appreciate that the present invention can be embodied in many other forms without departing from the spirit or scope thereof. Accordingly, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is intended to cover various modifications and substitutions without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A vehicle motion control method, characterized in that the method comprises:

receiving lane line information of a lane on which the vehicle runs, wherein the lane line information comprises a first lane line length and a second lane line length of the lane on which the vehicle runs;

determining a maximum allowable value c2_max and a minimum allowable value c2_min of the curvature of the lane center line at the current moment when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is smaller than a first threshold value and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value; and

updating the curvature c2 of the lane center line at the current time based on the maximum allowable value c2_max and the minimum allowable value c2_min, so that the vehicle motion controller can perform path planning and control on the own vehicle based on the updated curvature c2_update of the lane center line.

2. The method of claim 1, wherein receiving lane line information of a lane in which the host vehicle is traveling comprises:

signals relating to left and right lane lines of a driven lane are received from a video camera sensor.

3. The method of claim 1, wherein the relevant intelligent driving function is a traffic congestion assistance function TJA or a lane keeping function LKS.

4. The method of claim 1, wherein the first threshold is 15m and the second threshold is 0.0015.

5. The method of claim 1, wherein determining the maximum allowed value c2_max and the minimum allowed value c2_min of the lane centerline curvature at the current time when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is less than a first threshold and the curvature c2 of the lane centerline at the current time is less than a second threshold comprises:

the maximum allowable value c2_max and the minimum allowable value c2_min of the lane center line curvature at the present time are determined as follows:

c2_max=c2_k1+ calibration step size is cycle time;

c2 min=c2_k1-calibration step size-cycle time,

6. The method of claim 1, wherein updating the curvature c2 of the lane center line at the current time based on the maximum allowable value c2_max and the minimum allowable value c2_min comprises:

the updated curvature c2_update of the lane centerline is determined according to the following formula:

c2_update = max (c2_Min, min (c2, c2_Max))。

7. the method of claim 1, further comprising:

and when the related intelligent driving function is activated, the average value of the first lane line length and the second lane line length is smaller than a third threshold value, the current road gradient is larger than a calibration value, and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value, adjusting the target steering torque according to the current vehicle speed and the average value of the first lane line length and the second lane line length.

8. The method of claim 7, wherein adjusting the target steering torque based on the current vehicle speed and an average of the first lane line length and the second lane line length comprises:

obtaining an attenuation factor by looking up a table based on the current vehicle speed and the average value; and

and adjusting the target steering torque according to the attenuation factor.

9. A vehicle motion control apparatus, characterized by comprising:

the receiving device is used for receiving lane line information of a lane where the vehicle runs, wherein the lane line information comprises a first lane line length and a second lane line length of the lane where the vehicle runs;

determining means for determining a maximum allowable value c2_max and a minimum allowable value c2_min of the curvature of the lane center line at the present moment when the relevant intelligent driving function is activated, any one of the first lane line length and the second lane line length is smaller than a first threshold value and the curvature c2 of the lane center line at the present moment is smaller than a second threshold value; and

updating means for updating the curvature c2 of the lane center line at the present time based on the maximum allowable value c2_max and the minimum allowable value c2_min so that the vehicle motion controller can perform path planning and control for the own vehicle based on the updated curvature c2_update of the lane center line.

10. The apparatus of claim 9, wherein the receiving means is configured to:

11. The apparatus of claim 9, wherein the determining means is configured to determine a maximum allowable value c2_max and a minimum allowable value c2_min of the lane center line curvature at the current time according to the following formula:

c2_max=c2_k1+ calibration step size is cycle time;

c2 min=c2_k1-calibration step size-cycle time,

12. The apparatus of claim 9, wherein the updating means is configured to determine the updated curvature c2_update of the lane centerline according to the following formula:

c2_update = max (c2_Min, min (c2, c2_Max))。

13. the apparatus of claim 9, further comprising:

and the torque adjusting device is used for adjusting the target steering torque according to the current vehicle speed and the average value of the first lane line length and the second lane line length when the related intelligent driving function is activated, the average value of the first lane line length and the second lane line length is smaller than a third threshold value, the current road gradient is larger than a calibration value and the curvature c2 of the lane center line at the current moment is smaller than a second threshold value.

14. A computer program product comprising a computer program which, when executed by a processor, implements the method of any one of claims 1 to 8.

15. A vehicle, characterized in that it comprises an apparatus as claimed in any one of claims 9 to 13.