Control method and apparatus for lane change assist function

Abstract

The invention relates to a control method for a lane changing auxiliary function. The method comprises the steps that it is determined that the left side and the right side of an electric power steering system EPS are asymmetrical; adjusting a gain factor for the left side and / or the right side; and calculating a final steering request value of the lane change assist function based on the adjusted gain factor, and providing the final steering request value to the electric power steering system EPS. The application also relates to a control device for a lane change assistance function, a computer storage medium, a computer program product and an advanced driving assistance system (ADAS).

Description

Technical Field

[0001] The present application relates to the field of control of a lane change assist function, and more specifically, to a control method and device for a lane change assist function, a computer storage medium, a computer program product, and an advanced driver assistance system (ADAS). Background Art

[0002] After a vehicle has been used for a long time, the tires and chassis are likely to be worn or collided to varying degrees, resulting in inaccurate vehicle chassis data. In this case, even if the lane change assist function in the advanced driver assistance system ADAS issues the same steering request, when the electric power steering system EPS is executed, the performance on the left and right sides will be different (i.e. EPS is asymmetric), resulting in inconsistent left and right lane change performance.

[0003] For example, reference Figure 4 , which shows the inconsistent lane change performance due to the asymmetry of the electric power steering system EPS. Figure 4 In the left half of the figure, in the lane change situation 4010 to the left lane, since the lane change assist function in the ADAS will require the EPS to perform a left steering force when the vehicle 430 intends to change lanes to the left lane 410, the vehicle 430 may be pulled to the center line 415 of the left lane (i.e., the target lane) 410 at this time, as shown by the vehicle's trajectory line 440. Figure 4 In the lane-changing situation 4020 to the right lane shown in the right half of the figure, when the vehicle 430 intends to change lanes to the right lane 420, the lane-changing assist function in the ADAS will require the EPS to perform the same magnitude of steering force to the right. At this time, the vehicle 430 may be pulled across the center line 425 of the right lane 420, resulting in overshoot, as shown in the vehicle's trajectory line 450. Summary of the invention

[0004] The inventor of the present application realizes that the causes of the inconsistency of left and right lane change performance are relatively complex and may be caused by a variety of factors. Therefore, a solution is expected to compensate for the difference in left and right lane change performance caused by the asymmetry of the electric power steering system EPS and improve the performance of the lane change assist function.

[0005] According to one aspect of the present application, a control method for a lane change assist function is provided, the method comprising: determining that there is left-right asymmetry in an electric power steering system EPS; adjusting a gain factor for the left side and / or the right side; and calculating a final steering request value of the lane change assist function based on the adjusted gain factor, and providing the final steering request value to the electric power steering system EPS.

[0006] As a supplement or replacement for the above scheme, in the above method, determining whether the electric power steering system EPS has left-right asymmetry includes: after receiving a test request for the electric power steering system EPS, determining whether the vehicle is located at the center line of the lane; when the vehicle is not at the center line of the lane, correcting the vehicle to the center line of the lane (for example, if the vehicle is not currently at the center line of the lane, the lane centering keeping function is used to correct the vehicle to the vicinity of the center line of the lane (that is, the deviation between the vehicle and the center line of the lane is less than a certain threshold), and then issuing a "first steering request / second steering request"); sending the specified first steering request and second steering request to the electric power steering system EPS for execution so as to respectively test whether the electric power steering system EPS responds consistently to left and right steering, and the The amplitude and frequency of the first steering request and the second steering request are the same, and the phase difference between the two is half a cycle; a first steering wheel angle corresponding to the first steering request, a first lateral offset dy1 between the vehicle and the center line of the target lane corresponding to the first steering request, a second steering wheel angle corresponding to the second steering request, and a second lateral offset dy2 between the vehicle and the center line of the target lane corresponding to the second steering request are obtained; a first deviation between the amplitude and frequency of the first steering wheel angle and the second steering wheel angle and a second deviation between the first lateral offset and the second lateral offset are determined by comparison; and when the first deviation is greater than a first threshold and / or the second deviation is greater than a second threshold, it is determined that the electric power steering system EPS has left-right asymmetry.

[0007] As a supplement or alternative to the above solution, in the above method, the first steering request and the second steering request are both continuous sine curves, triangular waves or trapezoidal waves.

[0008] As a supplement or alternative to the above scheme, in the above method, adjusting the gain factor for the left side and / or the right side includes: adjusting the gain factor for the left side and / or the right side in the PID control according to the first deviation, the second deviation and the vehicle speed of the vehicle.

[0009] As a supplement or alternative to the above scheme, in the above method, calculating the final steering request value of the lane change assist function based on the adjusted gain factor includes: obtaining a proximal control steering request value associated with a first preview point, a first gain factor for the left side associated with the first preview point, and a second gain factor for the right side associated with the first preview point; obtaining a distal control steering request value associated with a second preview point, a third gain factor for the left side associated with the second preview point, and a fourth gain factor for the right side associated with the second preview point; and determining a final steering request value provided to the electric power steering system EPS based on the proximal control steering request value, the first gain factor, the second gain factor, the distal control steering request value, the third gain factor, and the fourth gain factor.

[0010] According to another aspect of the present application, a control device for a lane change assist function is provided, the device comprising: a determination device for determining whether there is left-right asymmetry in an electric power steering system EPS; an adjustment device for adjusting a gain factor for the left side and / or the right side; and a calculation device for calculating a final steering request value of the lane change assist function based on the adjusted gain factor, and providing the final steering request value to the electric power steering system EPS.

[0011] As a supplement or replacement for the above scheme, in the above device, the determination device is configured to: after receiving a test request for the electric power steering system EPS, determine whether the vehicle is located at the center line of the lane; when the vehicle is not at the center line of the lane, correct the vehicle to the center line of the lane (for example, if the vehicle is not currently at the center line of the lane, the lane centering keeping function is used to correct the vehicle to the vicinity of the center line of the lane (that is, the deviation between the vehicle and the center line of the lane is less than a certain threshold), and then issue a "first steering request / second steering request"); send the specified first steering request and second steering request to the electric power steering system EPS for execution so as to respectively test whether the electric power steering system EPS responds consistently to left and right steering, and the first steering request and The amplitude and frequency of the second steering request are the same, and the phase difference between the two is half a cycle; a first steering wheel angle corresponding to the first steering request, a first lateral offset dy1 between the vehicle and the center line of the target lane corresponding to the first steering request, a second steering wheel angle corresponding to the second steering request, and a second lateral offset dy2 between the vehicle and the center line of the target lane corresponding to the second steering request are obtained; a first deviation between the amplitude and frequency of the first steering wheel angle and the second steering wheel angle and a second deviation between the first lateral offset and the second lateral offset are determined by comparison; and when the first deviation is greater than a first threshold and / or the second deviation is greater than a second threshold, it is determined that the electric power steering system EPS has left-right asymmetry.

[0012] As a supplement or alternative to the above solution, in the above device, the first steering request and the second steering request are both continuous sine curves, triangular waves or trapezoidal waves.

[0013] As a supplement or alternative to the above solution, in the above device, the adjustment device is configured to: adjust the gain factor for the left side and / or right side in the PID control according to the first deviation, the second deviation and the vehicle speed of the vehicle.

[0014] As a supplement or alternative to the above scheme, in the above device, the computing device is configured to: obtain a proximal control steering request value associated with a first preview point in the PID control, a first gain factor for the left side associated with the first preview point, and a second gain factor for the right side associated with the first preview point; obtain a distal control steering request value associated with a second preview point in the PID control, a third gain factor for the left side associated with the second preview point, and a fourth gain factor for the right side associated with the second preview point; and determine a final steering request value provided to the electric power steering system EPS based on the proximal control steering request value, the first gain factor, the second gain factor, the distal control steering request value, the third gain factor, and the fourth gain factor.

[0015] According to another aspect of the present application, a computer storage medium is provided, wherein the medium includes instructions, and the instructions execute the above method when executed.

[0016] According to another aspect of the present application, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0017] According to yet another aspect of the present application, an advanced driving assistance system (ADAS) is provided. The advanced driving assistance system (ADAS) includes the device as described above.

[0018] The control scheme for the lane change assist function of the embodiment of the present application introduces a gain factor for the left and / or right side (the gain factor can be automatically adjusted when there is asymmetry between the left and right sides of the electric power steering system EPS), and calculates the final steering request value for the lane change assist function based on the adjusted gain factor, and the final steering request value is provided to the electric power steering system EPS to perform steering assistance. The above control scheme can compensate for the left and right lane change performance differences caused by the asymmetry of the electric power steering system EPS in a relatively simple way, and improve the performance of the lane change assist function. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects and advantages of the present application will become more fully apparent from the following detailed description in conjunction with the accompanying drawings, wherein the same or similar elements are represented by the same reference numerals.

[0020] Figure 1 A schematic flow chart of a control method for a lane change assist function according to an embodiment of the present application is shown;

[0021] Figure 2 A schematic structural diagram of a control device for a lane change assist function according to an embodiment of the present application is shown;

[0022] Figure 3 A logic diagram showing a control of a lane change assist function by introducing a gain factor (or an adjustable factor) according to an embodiment of the present application is shown; and

[0023] Figure 4 A schematic diagram showing a scenario in which inconsistent lane changing performance is caused by an asymmetric electric power steering system (EPS). DETAILED DESCRIPTION

[0024] Hereinafter, a control scheme for a lane change assist function according to various exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0025] Figure 1 FIG. 1 is a flow chart of a control method 1000 for a lane change assist function according to an embodiment of the present application. Figure 1 As shown, the control method 1000 for the lane change assist function includes the following steps:

[0026] In step S110, it is determined that the electric power steering system EPS has left-right asymmetry;

[0027] In step S120, the gain factor for the left side and / or the right side is adjusted; and

[0028] In step S130 , a final steering request value of the lane change assist function is calculated based on the adjusted gain factor, and the final steering request value is provided to the electric power steering system EPS.

[0029] In the context of this application, the term "lane change assist function" is also referred to as an automatic lane change function or Lane change function, which is located in a driving assistance system (such as ADAS). In one or more embodiments, the "lane change assist function" is used to assist the driver to drive the vehicle into an adjacent lane.

[0030] In step S110, it is determined that the EPS has left-right asymmetry. Here, "EPS has left-right asymmetry" means that when the EPS is executed, the performance of the left and right sides will be different (i.e., EPS is asymmetric), resulting in that even if the lane change assist function sends the same steering request to the EPS, the final left and right lane change performances are inconsistent. In one embodiment, step S110 includes: after receiving a test request for the electric power steering system EPS (for example, the driver triggers the test mode), determining whether the vehicle is located in the center line of the lane; if the vehicle is not currently in the center line of the lane, using the lane centering function to correct the vehicle to the vicinity of the center line of the lane (that is, the deviation between the vehicle and the center line of the lane is less than a certain threshold); then, sending a specified first steering request (denoted as Steering_req1) and a second steering request (denoted as Steering_req2) to the electric power steering system EPS for execution so as to respectively test whether the responses of the electric power steering system EPS to left and right steering are consistent, the first steering request and the second steering request have the same amplitude and frequency, and the phase difference between the two is half a cycle (it can be understood that the steering angle executed by the EPS will be reflected in the steering wheel angle, denoted as Steering_Wheel_angle); obtaining a first steering wheel angle corresponding to the first steering request angle (Steering_Wheel_angle1), a first lateral offset dy1 (for example, which can be calculated by lane line information) between the vehicle (for example, the center of the rear axle of the vehicle) and the center line of the target lane (for example, the center line of the left lane of the target) corresponding to the first steering request, a second steering wheel angle (Steering_Wheel_angle2) corresponding to the second steering request, and a second lateral offset dy2 (for example, which can be calculated by lane line information) between the vehicle (for example, the center of the rear axle of the vehicle) and the center line of the target lane (for example, the center line of the right lane of the target) corresponding to the second steering request; comparing and determining the first deviation between the amplitude and frequency of the first steering wheel angle and the second steering wheel angle and the second deviation between the first lateral offset and the second lateral offset; and when the first deviation is greater than a first threshold value and / or the second deviation is greater than a second threshold value, determining that the electric power steering system EPS has left-right asymmetry. In this way, the above scheme allows the driver to test the EPS by himself and trigger the automatic calibration process to fix the asymmetry problem.

[0031] It should be noted that, in one embodiment, the phase difference (half a cycle) between the first steering request and the second steering request is to ensure that the first steering request tests the response status of the EPS to the left turn request; the second steering request tests the response status of the EPS to the right turn request. Because usually, the steering request sign bit represents the direction of the steering request: left positive and right negative, or left negative and right positive. Those skilled in the art will understand that in one or more other embodiments, the direction of the steering request and the value of the steering request may be two different signals. Therefore, in this case, the "first steering request" and the "second steering request" need to consider two signals (i.e., the "direction signal of the steering request" and the "value of the steering request").

[0032] In the above embodiment, the first steering request and the second steering request can be continuous sine curves, triangular waves or trapezoidal waves, etc. In addition, if the left and right sides of the electric power steering system EPS respond in the same way, the amplitude and frequency of the first steering wheel angle and the second steering wheel angle should be very small, the response time should be synchronized, and the changes of dy1 and dy2 should also be consistent. Otherwise, there will be a large deviation in this information. In one embodiment, the gain factors of the left and right sides of the PID can be adjusted according to this deviation, so that the left and right sides of the electric power steering system EPS perform in the same way.

[0033] In step S120, the gain factors for the left side and / or the right side are adjusted. In one embodiment, step S120 includes: adjusting the gain factors for the left side and / or the right side in the PID control according to the first deviation, the second deviation and the vehicle speed of the vehicle. For example, when it is found that the vehicle trajectory line is overshooting, it can be determined according to the first deviation and the second deviation that the gain factors for the left side and / or the right side (for example, the default value is 1) need to be adjusted (for example, reduced), and the gain factors for the left side and / or the right side are adaptively adjusted according to the vehicle speed (for example, the higher the vehicle speed, the smaller the gain factor).

[0034] The following table shows an example of reducing the right side gain factor according to an embodiment of the present application. As shown in the following table, the right side gain factor decreases as the vehicle speed increases. This adjustment method is particularly suitable for the situation where the vehicle trajectory line "overshoots" when the vehicle changes lanes to the right.

[0035] Vehicle speed (km / h) 60 70 80 90 100 110 120 130 Right gain factor 1 0.9 0.85 0.8 0.75 0.7 0.65 0.6 Left gain factor 1 1 1 1 1 1 1 1

[0036] In other embodiments, the magnitudes of the left and right side gain factors may also be adjusted according to a first deviation between the amplitude and frequency of the first steering wheel angle and the second steering wheel angle and a second deviation between the first lateral offset and the second lateral offset.

[0037] In step S130, a final steering request value of the lane change assist function is calculated based on the adjusted gain factor, and the final steering request value is provided to the electric power steering system EPS. In one embodiment, step S130 includes: obtaining a proximal control steering request value associated with a first preview point (e.g., a proximal control point), a first gain factor for the left side associated with the first preview point, and a second gain factor for the right side associated with the first preview point; obtaining a distal control steering request value associated with a second preview point (e.g., a distal control point), a third gain factor for the left side associated with the second preview point, and a fourth gain factor for the right side associated with the second preview point; and determining a final steering request value for providing to the electric power steering system EPS according to the proximal control steering request value, the first gain factor, the second gain factor, the distal control steering request value, the third gain factor, and the fourth gain factor.

[0038] The first preview point and the second preview point are both prediction points, that is, a distance ahead is predicted relative to the center point of the rear axle of the vehicle. In one embodiment, the first preview point is a proximal control point, and the second preview point is a distal control point. The error amount required by the PID control module can be calculated based on the position information of the preview point and the lane centerline information, and then the steering request required to eliminate the error is calculated based on this error amount (that is, the "proximal control steering request value" or "distal control steering request value" is obtained). In one embodiment, the error calculated by the proximal preview is a lateral error, and the error calculated by the distal preview is a heading angle error.

[0039] Figure 3 FIG. 2 shows a logic diagram of controlling a lane change assist function by introducing a gain factor (or an adjustable factor) according to an embodiment of the present application. Figure 3 As shown, the near-end control steering request value 310 and the gain factor 315 associated with the near-end control point (e.g., the first gain factor for the left side and the second gain factor for the right side) are input to the first multiplier, and the far-end control steering request value 320 and the gain factor 325 associated with the far-end control point (e.g., the third gain factor for the left side and the fourth gain factor for the right side) are input to the second multiplier. The output of the first multiplier and the output of the second multiplier are input to the adder, and the final steering request value 330 is obtained, and the final steering request value 330 is provided to the electric power steering system EPS 340.

[0040] In addition, it is easy for a person skilled in the art to understand that the control method 1000 for the lane change assist function provided in the above one or more embodiments of the present application can be implemented by a computer program. For example, the computer program is included in a computer program product, and when the computer program is executed by a processor, the control method 1000 for the lane change assist function of one or more embodiments of the present application is implemented. For another example, when a computer storage medium (such as a USB flash drive) storing the computer program is connected to a computer, the control method 1000 for the lane change assist function of one or more embodiments of the present application can be executed by running the computer program.

[0041] Figure 2 FIG. 2 shows a schematic structural diagram of a control device 2000 for a lane change assist function according to an embodiment of the present application. Figure 2 As shown, the control device 2000 for the lane change assist function includes: a determining device 210, an adjusting device 220 and a calculating device 230. The determining device 210 is used to determine that the electric power steering system EPS has asymmetry between the left and right sides; the adjusting device 220 is used to adjust the gain factor for the left side and / or the right side; and the calculating device 230 is used to calculate the final steering request value of the lane change assist function based on the adjusted gain factor, and provide the final steering request value to the electric power steering system EPS.

[0042] In the context of this application, the term "lane change assist function" is also referred to as an automatic lane change function or Lane change function, which is located in a driving assistance system (such as ADAS). In one or more embodiments, the "lane change assist function" is used to assist the driver to drive the vehicle into an adjacent lane.

[0043] The determining device 210 is used to determine whether the EPS has left-right asymmetry. Here, “EPS has left-right asymmetry” means that when the EPS is executed, the performance of the left side and the right side will be different (i.e., the EPS is asymmetric), resulting in that even if the lane change assist function sends the same steering request to the EPS, the final lane change performance to the left and to the right is inconsistent. In one embodiment, the determination device 210 is configured to: after receiving a test request for the electric power steering system EPS (for example, the driver triggers the test mode), determine whether the vehicle is located in the center line of the lane; if the vehicle is not currently in the center line of the lane, use the lane centering function to correct the vehicle to the vicinity of the center line of the lane (that is, the deviation between the vehicle and the center line of the lane is less than a certain threshold); then, send a specified first steering request (denoted as Steering_req1) and a second steering request (denoted as Steering_req2) to the electric power steering system EPS for execution so as to test whether the responses of the electric power steering system EPS to left and right steering are consistent, respectively, the first steering request and the second steering request have the same amplitude and frequency, and the phase difference between the two is half a cycle (it can be understood that the steering angle executed by the EPS will be reflected in the steering wheel angle, denoted as Steering_Wheel_angle); obtain a first direction corresponding to the first steering request a first lateral offset dy1 (for example, which can be calculated through lane line information) between the host vehicle (for example, the center of the rear axle of the host vehicle) and the center line of the target lane (for example, the center line of the left lane of the target) corresponding to the first steering request, a second steering wheel angle (Steering_Wheel_angle2) corresponding to the second steering request, and a second lateral offset dy2 (for example, which can be calculated through lane line information) between the host vehicle (for example, the center of the rear axle of the host vehicle) and the center line of the target lane (for example, the center line of the right lane of the target) corresponding to the second steering request; comparing and determining a first deviation between the amplitude and frequency of the first steering wheel angle and the second steering wheel angle and a second deviation between the first lateral offset and the second lateral offset; and when the first deviation is greater than a first threshold value and / or the second deviation is greater than a second threshold value, determining that the electric power steering system EPS has left-right asymmetry.

[0044] It should be noted that, in one embodiment, the phase difference (half a cycle) between the first steering request and the second steering request is to ensure that the first steering request tests the response status of the EPS to the left turn request; the second steering request tests the response status of the EPS to the right turn request. Because usually, the steering request sign bit represents the direction of the steering request: left positive and right negative, or left negative and right positive. Those skilled in the art will understand that in one or more other embodiments, the direction of the steering request and the value of the steering request may be two different signals. Therefore, in this case, the "first steering request" and the "second steering request" need to consider two signals (i.e., the "direction signal of the steering request" and the "value of the steering request").

[0045] In the above embodiment, the first steering request and the second steering request can be continuous sine curves, triangular waves or trapezoidal waves, etc. In addition, if the left and right sides of the electric power steering system EPS respond in the same way, the amplitude and frequency of the first steering wheel angle and the second steering wheel angle should differ very little, the response time should be synchronized, and the changes of dy1 and dy2 should also be consistent. Otherwise, there will be a relatively large deviation in this information. In one embodiment, the adjustment device 220 can adjust the gain factors of the left and right sides of the PID according to this deviation, so that the left and right sides of the electric power steering system EPS perform in the same way.

[0046] Specifically, the adjustment device 220 is used to adjust the gain factor for the left side and / or the right side. In one embodiment, the adjustment device 220 is configured to: adjust the gain factor for the left side and / or the right side in the PID control according to the first deviation, the second deviation and the vehicle speed of the vehicle. For example, when it is found that the vehicle trajectory line is overshooting, the adjustment device 220 can determine that the gain factor (for example, the default value is 1) on the left side and / or the right side needs to be adjusted (for example, reduced) according to the first deviation and the second deviation, and adaptively adjust the gain factor on the left side and / or the right side according to the vehicle speed (for example, the higher the vehicle speed, the smaller the gain factor).

[0047] The following table shows an example of reducing the right side gain factor according to an embodiment of the present application. As shown in the following table, the right side gain factor decreases as the vehicle speed increases. This adjustment method of the adjustment device 220 is particularly suitable for the situation where the vehicle trajectory line "overshoots" when the vehicle changes lanes to the right.

[0048] Vehicle speed (km / h) 60 70 80 90 100 110 120 130 Right gain factor 1 0.9 0.85 0.8 0.75 0.7 0.65 0.6 Left gain factor 1 1 1 1 1 1 1 1

[0049] It should be understood that in addition to the list method, in other embodiments, the adjustment device 220 can also calculate the size of the left and right side gain factors in real time based on the first deviation between the amplitude and frequency of the first steering wheel angle and the second steering wheel angle and the second deviation between the first lateral offset and the second lateral offset.

[0050] The computing device 230 is used to calculate the final steering request value of the lane change assist function based on the adjusted gain factor, and provide the final steering request value to the electric power steering system EPS. In one embodiment, the computing device 230 is configured to: obtain a proximal control steering request value associated with a first preview point (e.g., a proximal control point), a first gain factor for the left side associated with the first preview point, and a second gain factor for the right side associated with the first preview point; obtain a distal control steering request value associated with a second preview point (e.g., a distal control point), a third gain factor for the left side associated with the second preview point, and a fourth gain factor for the right side associated with the second preview point; and determine the final steering request value provided to the electric power steering system EPS according to the proximal control steering request value, the first gain factor, the second gain factor, the distal control steering request value, the third gain factor, and the fourth gain factor.

[0051] The first preview point and the second preview point are both prediction points, that is, a distance ahead is predicted relative to the center point of the rear axle of the vehicle. In one embodiment, the first preview point is a proximal control point, and the second preview point is a distal control point. The computing device 230 calculates the error amount required by the PID control module based on the position information of the preview point and the lane centerline information, and then calculates the steering request required to eliminate the error based on the error amount (that is, obtains the "proximal control steering request value" or the "distal control steering request value"). In one embodiment, the error calculated by the proximal preview is a lateral error, and the error calculated by the distal preview is a heading angle error.

[0052] In one embodiment, the control device 2000 for the lane change assist function may be integrated into various advanced driving assistance systems ADAS. In one embodiment, the advanced driving assistance system ADAS may be installed in a vehicle.

[0053] "Advanced driver assistance system", also known as ADAS or advanced driver assistance system. It uses various sensors installed on the car (such as millimeter wave radar, lidar, single / binocular camera and satellite navigation) to sense the surrounding environment at any time during the car's driving, collect data, identify, detect and track static and dynamic objects, and combine navigation map data to perform systematic calculations and analysis, so as to make the driver aware of possible dangers in advance, effectively increasing the comfort and safety of car driving. In one embodiment, in addition to the lane change assistance function, the advanced driving assistance system may also include a navigation and real-time traffic system TMC, an electronic police system ISA (Intelligent speed adaptation or intelligent speed advice), a vehicle network (Vehicular communication systems), an adaptive cruise control ACC (Adaptive cruise control), a lane departure warning system LDWS (Lane departure warning system), a lane keeping system (Lane keep assistance), a collision avoidance or pre-collision system (Collisionavoidance system or Precrash system), a night vision system (Night Vision system), an adaptive light control (Adaptive light control), a pedestrian protection system (Pedestrian protection system), an automatic parking system (Automatic parking), traffic sign recognition (Traffic sign recognition), a blind spot detection (Blind spot detection), a driver fatigue detection (Driver drowsiness detection), a downhill control system (Hill descent control) and an electric vehicle warning sounds (Electric vehicle warning sounds) system, etc.

[0054] In summary, the control scheme for the lane change assist function in the embodiment of the present application introduces a gain factor for the left and / or right side (the gain factor can be automatically adjusted when there is a left-right asymmetry in the electric power steering system EPS), and calculates the final steering request value for the lane change assist function based on the adjusted gain factor, and the final steering request value is provided to the electric power steering system EPS to perform steering assistance. The above control scheme can compensate for the left-right lane change performance difference caused by the asymmetry of the electric power steering system EPS in a relatively simple way, thereby improving the performance of the lane change assist function. In addition, the above scheme allows the driver to test the EPS by himself and trigger the automatic calibration process to fix the asymmetry problem.

[0055] The above examples mainly illustrate the control scheme for the lane change assist function of the embodiment of the present application. Although only some of the implementation methods of the present application are described, it should be understood by those skilled in the art that the present application can be implemented in many other forms without departing from its subject matter and scope. Therefore, the examples and implementation methods shown are regarded as illustrative rather than restrictive, and the present application may cover various modifications and substitutions without departing from the spirit and scope of the present application as defined in the claims.

Claims

1. A control method for a lane change assist function, characterized in that: The method comprises: Determine that the electric power steering system EPS is asymmetric on the left and right sides; Adjusting the gain factor for the left and / or right sides; and A final steering request value of the lane change assist function is calculated based on the adjusted gain factor, and the final steering request value is provided to the electric power steering system EPS.

2. The method of claim 1, wherein: Determining whether the electric power steering system EPS has left-right asymmetry includes: After receiving a test request for the electric power steering system EPS, determining whether the vehicle is located at the center line of the lane; When the vehicle is not on the center line of the lane, using a lane centering function to correct the vehicle to the center line of the lane; Sending a designated first steering request and a designated second steering request to the electric power steering system EPS for execution so as to respectively test whether the responses of the electric power steering system EPS to left and right steering are consistent, wherein the amplitude and frequency of the first steering request and the second steering request are the same, and the phase difference between the two is half a cycle; Obtaining a first steering wheel angle corresponding to the first steering request, a first lateral offset dy1 between the vehicle and the center line of the target lane corresponding to the first steering request, a second steering wheel angle corresponding to the second steering request, and a second lateral offset dy2 between the vehicle and the center line of the target lane corresponding to the second steering request; Determining a first deviation between the amplitude and the frequency of the first steering wheel angle and the second steering wheel angle and a second deviation between the first lateral offset and the second lateral offset by comparing; and When the first deviation is greater than a first threshold value and / or the second deviation is greater than a second threshold value, it is determined that there is left-right asymmetry in the electric power steering system EPS.

3. The method of claim 2, wherein: The first steering request and the second steering request are both continuous sinusoidal waves, triangular waves or trapezoidal waves.

4. The method of claim 2, wherein: Adjusting the gain factors for the left and / or right sides involves: The gain factors for the left side and / or the right side in the PID control are adjusted according to the first deviation, the second deviation and the vehicle speed of the host vehicle.

5. The method of claim 4, wherein: Calculating the final steering request value of the lane change assist function based on the adjusted gain factor includes: Obtaining a proximal control steering request value associated with a first preview point, a first gain factor for a left side associated with the first preview point, and a second gain factor for a right side associated with the first preview point; Obtaining a remote control steering request value associated with a second preview point, a third gain factor for a left side associated with the second preview point, and a fourth gain factor for a right side associated with the second preview point; and A final steering request value provided to the electric power steering system EPS is determined according to the proximal control steering request value, the first gain factor, the second gain factor, the distal control steering request value, the third gain factor, and the fourth gain factor.

6. A control device for a lane change assist function, characterized in that: The device comprises: A determination device, used for determining whether an electric power steering system EPS has left-right asymmetry; adjustment means for adjusting the gain factor for the left side and / or the right side; and A calculation device is used to calculate a final steering request value of the lane change assist function based on the adjusted gain factor, and provide the final steering request value to the electric power steering system EPS.

7. The device of claim 6, wherein: The determining device is configured to: After receiving a test request for the electric power steering system EPS, determining whether the vehicle is located at the center line of the lane; When the vehicle is not on the center line of the lane, using a lane centering function to correct the vehicle to the center line of the lane; Sending a designated first steering request and a designated second steering request to the electric power steering system EPS for execution so as to respectively test whether the responses of the electric power steering system EPS to left and right steering are consistent, wherein the amplitude and frequency of the first steering request and the second steering request are the same, and the phase difference between the two is half a cycle; Obtaining a first steering wheel angle corresponding to the first steering request, a first lateral offset dy1 between the vehicle and the center line of the target lane corresponding to the first steering request, a second steering wheel angle corresponding to the second steering request, and a second lateral offset dy2 between the vehicle and the center line of the target lane corresponding to the second steering request; Determine a first deviation between the amplitude and the frequency of the first steering wheel angle and the second steering wheel angle and a second deviation between the first lateral offset and the second lateral offset by comparing; as well as When the first deviation is greater than a first threshold value and / or the second deviation is greater than a second threshold value, it is determined that there is left-right asymmetry in the electric power steering system EPS.

8. The device of claim 7, wherein: The first steering request and the second steering request are both continuous sinusoidal waves, triangular waves or trapezoidal waves.

9. The device of claim 7, wherein: The adjustment device is configured to adjust the gain factor for the left side and / or the right side in the PID control according to the first deviation, the second deviation and the vehicle speed of the vehicle.

10. The device of claim 9, wherein: The computing device is configured to: Obtaining a proximal control steering request value associated with a first preview point in the PID control, a first gain factor for a left side associated with the first preview point, and a second gain factor for a right side associated with the first preview point; Obtaining a remote control steering request value associated with a second preview point in the PID control, a third gain factor for a left side associated with the second preview point, and a fourth gain factor for a right side associated with the second preview point; as well as A final steering request value provided to the electric power steering system EPS is determined according to the proximal control steering request value, the first gain factor, the second gain factor, the distal control steering request value, the third gain factor, and the fourth gain factor.

11. A computer storage medium, characterized in that: The medium includes instructions which, when executed, perform the method of any one of claims 1 to 5.

12. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

13. An advanced driver assistance system ADAS, characterized in that: The advanced driver assistance system ADAS comprises the apparatus according to any one of claims 6 to 10.

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