Vehicle motion control method and system

Abstract

The invention discloses a vehicle motion control method. The vehicle motion control method comprises the following steps: confirming that an S-shaped curve scene exists in a front road (S1); and adjusting the limit value of the lateral acceleration when it is detected that the steering wheel is reversely turned and the current lateral acceleration of the vehicle is greater than the lateral acceleration threshold (S2). The invention also discloses a vehicle motion control system and a computer program product. According to some exemplary embodiments of the invention, vehicle driving can be flexibly assisted, and the safety of vehicle driving can be improved.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and in particular to a vehicle motion control method and system. Background Art

[0002] With the development of science and technology, the application scenarios of vehicle driving are becoming more and more extensive. In some special scenarios, such as continuous curves, ramp entrances and exits, winding mountain roads and other sections, the recognition range of the vehicle sensor system may be limited. In order to ensure the safety of vehicle driving, the vehicle motion control system may constrain the various motion parameters of the vehicle. However, this constraint cannot flexibly adapt to actual driving needs and it is difficult to deal with potential vehicle driving risks.

[0003] Therefore, it is expected to provide a vehicle motion control method that can flexibly assist vehicle driving to improve the safety of vehicle driving. Summary of the invention

[0004] In order to overcome one of the above disadvantages and / or other possible disadvantages in the prior art not mentioned herein, an object of the present invention is to provide a vehicle motion control method and system, and a computer program product.

[0005] To ensure safety, vehicles will constrain various motion parameters, especially setting an initial limit value for lateral acceleration. This limit on lateral acceleration will constrain the vehicle's motion performance. When the vehicle is driving on a curve, especially during continuous turning, inappropriate lateral acceleration limit will cause the vehicle to be unable to respond quickly to lane changes, thereby bringing potential risks. The present invention particularly includes the following technical concepts: when the vehicle is driving on a curve, especially during continuous turning, the limit value of the vehicle's lateral acceleration can be adjusted in real time and appropriately, so that the vehicle can respond quickly to lane changes, thereby making the vehicle's motion control more flexible and the vehicle driving safer.

[0006] According to one aspect of the present invention, a vehicle motion control method is provided, which includes step S1: confirming that there is an S-curve scene in the road ahead; and step S2: when a steering wheel reverse is detected and the current lateral acceleration of the vehicle is greater than a lateral acceleration threshold, adjusting a limit value of the lateral acceleration.

[0007] According to an optional embodiment of the present invention, in step S1, the presence of an S-shaped curve scene in the road ahead is confirmed based on the change in the attitude angle of the vehicle relative to the center line of the current lane, and when the rate of change of the attitude angle is greater than a threshold value of the attitude angle change rate, it is confirmed that there is an S-shaped curve scene in the road ahead.

[0008] According to an optional embodiment of the present invention, in step S1, the presence of an S-curve scene in the road ahead is confirmed based on the change in the vehicle's attitude angle relative to the center line of the current lane, as well as the sensing range of the vehicle's sensing system and / or the steering wheel counter-steering condition.

[0009] According to an optional embodiment of the present invention, when the rate of change of the attitude angle is greater than a threshold value of the rate of change of the attitude angle, and the sensing range of the vehicle sensing system is less than the sensing threshold and / or the steering wheel is detected to be reversed, it is confirmed that there is an S-turn scene in the road ahead; or, a weighted sum is taken of the rate of change of the attitude angle, the maximum value of the sensing range of the vehicle sensing system, and the reverse angle value when the steering wheel is reversed, and when the weighted sum is greater than or equal to a preset sum value, it is confirmed that there is an S-turn scene in the road ahead.

[0010] According to an optional embodiment of the present invention, in step S2, when adjusting the limit value of the lateral acceleration, the limit value of the lateral acceleration in the reverse steering direction is adjusted to be larger, while the limit value of the lateral acceleration in the other direction remains unchanged.

[0011] According to an optional embodiment of the present invention, the lateral acceleration threshold is a product of an initial limit value of the lateral acceleration and a predetermined coefficient, and the predetermined coefficient ranges from 0.6 to 1.

[0012] According to an optional embodiment of the present invention, the attitude angle is the angle between the center line of the front of the vehicle and the center line of the current lane.

[0013] According to an optional embodiment of the present invention, the sensing range of the vehicle sensing system is an angle range and / or a distance range within which the vehicle sensing system senses the surrounding environment of the vehicle.

[0014] According to a second aspect of the present invention, a vehicle motion control system is provided, which includes: a confirmation module, which is configured to confirm the existence of an S-curve scene in the road ahead; and a control module, which is configured to adjust the limit value of the lateral acceleration when the steering wheel is detected to be reversed and the current lateral acceleration of the vehicle is greater than the lateral acceleration threshold.

[0015] According to a third aspect of the present invention, there is provided a computer program product, such as a machine-readable storage medium, comprising or storing computer program instructions, the computer program being suitable for executing a vehicle motion control method when run on a computer.

[0016] According to certain exemplary embodiments of the present invention, it is particularly suitable for special road sections such as S-curves, can flexibly assist vehicle driving, and can improve the safety of vehicle driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be described in more detail below with reference to the accompanying drawings, so that the principles, features and advantages of the present invention can be better understood. The accompanying drawings include:

[0018] Figure 1 The diagram shows a schematic diagram of the sensing range of the vehicle sensing system for the lane condition in the forward direction of the vehicle when the vehicle is traveling in an S-shaped ramp.

[0019] Figure 2 A flow chart of a vehicle motion control method according to an exemplary embodiment of the present invention is shown.

[0020] Figure 3 A schematic diagram showing a vehicle driving in an S-curve scenario according to an exemplary embodiment of the present invention is shown.

[0021] Figure 4 A schematic diagram showing a vehicle traveling in another S-curve scenario according to an exemplary embodiment of the present invention is shown.

[0022] Figure 5 A schematic block diagram of a vehicle motion control system according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0023] In order to make the technical problems, technical solutions and beneficial technical effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and multiple exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the scope of protection of the present invention.

[0024] Figure 1 FIG. 1 is a schematic diagram showing the sensing range of the vehicle sensing system for the lane condition in the forward direction of the vehicle when the vehicle is traveling in an S-shaped ramp. Figure 1 In the driving scenario of an S-curve, the vehicle sensor system has deficiencies in identifying the lane centerline. The lane centerline can be the virtual centerline of the lane actually marked on the urban road, or the virtual centerline of the road where the vehicle is actually located without a marked lane. When the vehicle is driving in the first half of the S-curve (such as Figure 1 As shown in the upper left figure, based on the performance of the sensing system, it is difficult for the vehicle to sense enough information to fit the complete S-shaped lane centerline, and can only fit the first half of the lane centerline (as shown in the upper left figure). Figure 1 As shown in the lower left, the vehicle also has difficulty recognizing that the current driving scene corresponds to an S-curve. The vehicle can only recognize that the current driving scene corresponds to an S-curve when it reaches the second half of the S-curve (as shown in the lower left). Figure 1 The vehicle can fit the second half of the center line of the S-shaped lane (as shown in the upper right side). Figure 1In this case, the vehicle's recognition and confirmation of the S-curve is too delayed, and it is unable to provide the vehicle's motion control with predictive information about the road conditions in the vehicle's forward direction, making it difficult to fully and effectively ensure vehicle driving safety. The sensor lag may even cause the vehicle controller to not have enough reaction time to reverse the steering wheel in time, causing the vehicle to run out of the lane.

[0025] In fact, except for driving scenarios on S-shaped curves, vehicles face the same problem in other driving scenarios such as L-shaped lanes, C-shaped lanes, and continuous curves, namely, when the lane is curved, especially in scenarios where the curvature of the lane is large, the sensing range of the vehicle sensing system becomes smaller and the sensing function is greatly weakened. It is impossible to automatically fit the lane centerline in the vehicle's forward direction in advance. It is difficult to predict the vehicle's driving in an S-shaped curve scenario by relying solely on the vehicle sensing system, and it is even more difficult to accurately intervene in the vehicle's motion control strategy in advance, and it is impossible to always reliably provide lane keeping assist functions. In addition, when the sensing range of the vehicle sensing system becomes smaller, in particular, when the sensing range is less than a preset sensing range threshold, the vehicle control system will automatically reduce the confidence of the lane keeping assist function provided by the vehicle sensing system. At the same time, the vehicle control system will adopt a conservative control strategy, and the constraints on the vehicle's operating performance will tend to be stricter, such as appropriately adjusting and reducing the limit values ​​of various vehicle operating parameters. In particular, the initial limit value of the vehicle's lateral acceleration is adjusted to a smaller value. In this case, when the vehicle is driving on an S-shaped curve and enters the lower half of the S-curve, the vehicle will not be able to obtain a sufficiently large lateral acceleration to quickly respond to lane changes, which is not conducive to the vehicle staying in the lane, and there is a safety hazard of the vehicle running out of the lane.

[0026] Figure 2 A flow chart of a vehicle motion control method according to an exemplary embodiment of the present invention is shown, the method comprising at least steps S1 and S2. Through the method of the present invention, the condition of the road ahead can be accurately identified, especially the condition of an S-curve scene in the road ahead, thereby providing sufficient prejudgment information, facilitating lane keeping, and ensuring vehicle driving safety.

[0027] In step S1 of this exemplary embodiment, the presence of an S-shaped curve scene in the road ahead is confirmed. The presence of an S-shaped curve scene in the road ahead is identified based on the change in the attitude angle of the vehicle relative to the center line of the current lane. When the rate of change of the attitude angle is greater than the attitude angle change rate threshold, the presence of an S-shaped curve scene in the road ahead is confirmed. The attitude angle may be, for example, the angle between the center line of the vehicle and the center line of the current lane, that is, the presence of an S-shaped curve scene in the road ahead is identified based on the change in the angle between the center line of the vehicle and the center line of the current lane. When the angle between the center line of the vehicle and the center line of the current lane suddenly changes, or the rate of change of the angle is greater than the angle change rate threshold, the presence of an S-shaped curve scene in the road ahead is confirmed.

[0028] In this case, the vehicle's sensing of the road conditions in the forward direction no longer relies entirely on the vehicle's sensor system, but predicts the road conditions in the forward direction in real time based on the vehicle's current posture relative to the centerline of the lane where it is located. In this way, there is no need to add additional sensors, only the vehicle's current posture angle needs to be calculated. Some vehicles' existing control strategies also calculate various posture angles of the vehicle relative to the centerline of the lane, and even only the calculation results of the posture angle need to be directly called. There is no need to add additional calculation and processing steps, which saves the calculation and processing capabilities within the control system.

[0029] Optionally, the attitude angle change rate threshold or the angle change rate threshold can be pre-measured and stored locally in the form of a chart according to different vehicle models and vehicle operating conditions, as well as the user's driving habits. When the vehicle is running, the matching attitude angle change rate threshold or the angle change rate threshold can be obtained by querying the chart according to the current vehicle operating conditions and the user's driving habits. Specifically, the attitude angle change rate threshold or the angle change rate threshold is associated with the vehicle's current longitudinal driving speed or longitudinal driving acceleration. For example, when the vehicle's longitudinal driving speed or longitudinal driving acceleration is relatively large, the corresponding attitude angle change rate threshold or the angle change rate threshold is relatively small, so that the adjustment response speed of the vehicle control strategy matches the vehicle's driving speed.

[0030] Optionally, in order to further ensure the accuracy of the recognition and confirmation of the S-curve scene and prevent the sudden lane change of the vehicle from being mistakenly identified as the existence of an S-curve scene in the road ahead, in step S1, the existence of an S-curve scene in the road ahead can also be identified and confirmed in combination with the sensing range of the vehicle sensing system and / or the steering wheel reverse situation; when the change rate of the attitude angle is greater than the attitude angle change rate threshold, and the sensing range of the vehicle sensing system is less than the sensing threshold, and / or the steering wheel reverse is detected, it is confirmed that there is an S-curve scene in the road ahead. In this case, when the attitude angle changes suddenly, or the rate of change of the attitude angle is greater than the preset attitude angle change rate threshold, it is not directly confirmed that there is an S-turn scene in the road ahead. In order to improve reliability and avoid unnecessary adjustment of the limit value of lateral acceleration, the sensing range of the vehicle sensing system and the steering wheel reverse are further judged. Only when the rate of change of the attitude angle of the vehicle relative to the center line of the lane at the current position is greater than the attitude angle change rate threshold, and the sensing range of the vehicle sensing system is less than the sensing threshold, and the steering wheel reverse is detected, is it confirmed that there is an S-turn scene in the road ahead.

[0031] Optionally, the rate of change of the attitude angle, the maximum value of the sensing range of the vehicle sensing system, and the reverse angle value when the steering wheel is reversed can be weighted and summed. When the weighted sum is greater than or equal to the preset sum, it is confirmed that there is an S-shaped curve scene in the road ahead. The reverse angle value refers to the angle value of the steering wheel deviating from the steering wheel's return position after the steering wheel is reversed when the steering wheel is reversed. In addition, the sensing range may refer to a sensing angle range and a sensing distance range depending on the type of the sensing system. For example, the sensing system may include a radar system, an ultrasonic sensing system, and a camera system. The sensing ranges of these sensing systems may include a sensing angle range and a sensing distance range. The maximum value of the sensing range of the vehicle sensing system may be the maximum angle value of the sensing angle range, or the maximum distance value of the sensing distance range.

[0032] In the step S2 of the present invention, when the steering wheel is detected to be reversed and the current lateral acceleration of the vehicle is greater than the lateral acceleration threshold, the limit value of the lateral acceleration is adjusted. Wherein, the lateral acceleration threshold is less than or equal to the initial limit value of the lateral acceleration set for the vehicle, and the lateral acceleration threshold can be set as a fixed value for different vehicle models. Preferably, the lateral acceleration threshold can be the product of the initial limit value of the lateral acceleration and a predetermined coefficient, and the predetermined coefficient can be 0.6 to 1. Specifically, the current lateral acceleration of the vehicle can be determined by calculating the ratio of the current lateral acceleration of the vehicle to the initial limit value of the lateral acceleration to determine whether the current lateral acceleration of the vehicle is greater than the lateral acceleration threshold, thereby determining whether to adjust the limit value of the lateral acceleration. When the ratio is 0.6 to 1, the limit value of the lateral acceleration is adjusted; in particular, when the ratio of the current vehicle lateral acceleration to the initial limit value of the lateral acceleration is close to 1, that is, when the current vehicle lateral acceleration touches the initial limit value of the lateral acceleration, the limit value of the lateral acceleration is adjusted. Additionally, the initial limit value of the lateral acceleration can be set as a fixed value according to different vehicle models, or it can be calculated in real time based on the vehicle operating conditions and the user's driving habits, or it can be measured in advance and stored locally in the form of a chart. When the vehicle is running, the initial limit value of the lateral acceleration can be obtained in real time by querying the chart based on the current vehicle operating conditions and the user's driving habits.

[0033] Optionally, after the lateral acceleration limit value is adjusted in step S2, the sensing range of the vehicle sensing system is gradually restored to a range greater than a threshold value, and after the vehicle continues to travel for a time longer than a specified time after adjusting the lateral acceleration limit value, the vehicle will automatically restore the lateral acceleration limit value to the initial lateral acceleration limit value. Additionally, the initial lateral acceleration limit value can be calculated in real time, or it can be obtained in real time by querying a chart based on the current operating condition of the vehicle and the driving habits of the user.

[0034] Optionally, when adjusting the limit value of the lateral acceleration, the limit value of the lateral acceleration in the reverse steering direction is adjusted to be larger, while the limit value of the lateral acceleration in the other direction remains unchanged. Therefore, a safety constraint in the other direction can be effectively provided to prevent the driver from making a wrong operation, which is conducive to ensuring driving safety.

[0035] Optionally, the detection of the steering wheel reverse refers to the detection of the steering wheel deviating from the return position to one side and changing from the return position to the other side. In addition, based on the fact that the distance of the curve is limited and the vehicle generally drives through the curve continuously, the time for the vehicle to pass the curve is also limited. At this time, a preset time can also be set. Only when the steering wheel is detected to deviate from the return position to one side and change from the return position to the other side within the preset time, the reverse wheel reverse is detected, thereby preventing the vehicle from misidentifying the scene during long-term driving. In particular, the detection of the steering wheel reverse refers to the detection of the steering wheel deviating from the return position to one side and changing from the return position to the other side within the preset time.

[0036] Figure 3 A schematic diagram showing a vehicle driving in an S-curve scenario according to an exemplary embodiment of the present invention is shown; Figure 4 A schematic diagram showing a vehicle traveling in another S-curve scenario according to an exemplary embodiment of the present invention is shown. Figure 3 and Figure 4 The states of the vehicle at different positions of the ramp are shown respectively. It can be seen that according to the vehicle motion control method of the present invention, the vehicle can safely and reliably leave the main lane from the continuously turning S-shaped curve, and can also merge into the main lane from the continuously turning S-shaped curve.

[0037] like Figure 3 After the vehicle leaves the main lane and enters the S-shaped ramp, the sensing range of the vehicle sensor system becomes smaller. It is difficult to accurately identify the complete S-shaped lane centerline of the ramp by relying solely on the vehicle sensor system. At this time, it is necessary to use the vehicle motion control method of the present invention to obtain the vehicle's attitude angle relative to the current lane centerline in real time after the vehicle enters the ramp, such as the angle between the centerline of the front of the vehicle and the centerline of the lane. At this time, in order to keep the vehicle in the lane, the steering wheel will go through the following process while the vehicle passes through the ramp: it will deflect to the right from the original steering wheel return position, and then deflect to the left from the steering wheel return position after returning to the center, that is, the steering wheel will turn left before the vehicle reaches the ramp exit. At the same time, the vehicle's attitude will inevitably change in advance before reaching the ramp exit, such as Figure 3 , combined with the fact that the vehicle's posture relative to the center line of the current lane has changed from deviating to the right to deviating to the left, the sensing range of the vehicle's sensor system has become smaller, and the steering wheel has been turned to the left, a comprehensive judgment can confirm that the vehicle is driving in an S-shaped curve scenario.

[0038] like Figure 4When the vehicle merges into the main lane from the S-shaped ramp, the sensing range of the vehicle sensor system becomes smaller. It is difficult to accurately identify the complete S-shaped lane centerline of the ramp by relying solely on the vehicle sensor system. At this time, it is necessary to use the vehicle motion control method of the present invention to obtain the vehicle's attitude angle relative to the current lane centerline in real time after the vehicle enters the ramp, such as the angle between the centerline of the front of the vehicle and the centerline of the lane. At this time, in order to keep the vehicle on the ramp, the steering wheel will go through the following process while the vehicle passes through the ramp: it will deflect to the left from the original steering wheel return position, and then deflect to the right from the steering wheel return position after returning to the center position, that is, the steering wheel will turn to the right before the vehicle reaches the ramp exit. At the same time, the vehicle's attitude will inevitably change in advance before reaching the ramp exit, such as Figure 4 , combined with the fact that the vehicle's deviation from the original left deviation to the right relative to the lane centerline, the smaller sensing range of the vehicle's sensor system, and the steering wheel turning to the right, a comprehensive judgment can confirm that the vehicle is driving in an S-shaped curve scenario.

[0039] Figure 5 : shows a schematic block diagram of a vehicle motion control system according to an exemplary embodiment of the present invention,

[0040] The vehicle motion control system includes the following components:

[0041] A confirmation module 10, which is configured to confirm that there is an S-curve scene in the road ahead;

[0042] The control module 20 is configured to adjust the limit value of the lateral acceleration when the steering wheel is detected to be in reverse and the current lateral acceleration of the vehicle is greater than the lateral acceleration threshold.

[0043] Optionally, the vehicle motion control system also has a binocular camera for lane centerline detection and can provide active lane keeping assist (LKA) function.

[0044] Although specific embodiments have been described above, these embodiments are not intended to limit the scope of the present disclosure, even when only a single embodiment is described with respect to specific features. The feature examples provided in the present disclosure are intended to be illustrative, not limiting, unless otherwise expressly stated. In specific implementations, multiple features can be combined with each other where technically feasible, depending on actual needs. Various substitutions, changes, and modifications may also be conceived without departing from the spirit and scope of the present invention.

Claims

1. A vehicle motion control method, the vehicle motion control method comprising: Step S1: confirming that there is an S-shaped curve scene on the road ahead; and Step S2: When the steering wheel is detected to be in reverse and the current lateral acceleration of the vehicle is greater than the lateral acceleration threshold, the limit value of the lateral acceleration is adjusted.

2. The vehicle motion control method according to claim 1, characterized in that: In step S1, the presence of an S-curve scene in the road ahead is confirmed based on the change in the vehicle's attitude angle relative to the center line of the current lane. When the change rate of the attitude angle is greater than the attitude angle change rate threshold, it is confirmed that there is an S-curve scene in the road ahead.

3. The vehicle motion control method according to claim 1, characterized in that: In step S1, the presence of an S-curve scene in the road ahead is confirmed based on the change in the vehicle's attitude angle relative to the center line of the current lane, as well as the sensing range of the vehicle's sensor system and / or the steering wheel's reverse steering.

4. The vehicle motion control method according to claim 3, characterized in that: When the rate of change of the attitude angle is greater than the attitude angle change rate threshold, and the sensing range of the vehicle sensing system is less than the sensing threshold and / or the steering wheel is detected to be reversed, it is confirmed that there is an S-shaped curve scene in the road ahead; or, A weighted sum is taken of the rate of change of the attitude angle, the maximum value of the sensing range of the vehicle sensing system, and the steering wheel reverse angle value. When the weighted sum is greater than or equal to the preset sum value, it is confirmed that there is an S-shaped curve scene in the road ahead.

5. The vehicle motion control method according to claim 1, characterized in that: In step S2, when adjusting the limit value of the lateral acceleration, the limit value of the lateral acceleration in the direction of the steering wheel counter-steering is adjusted to be larger, while the limit value of the lateral acceleration in the other direction remains unchanged.

6. The vehicle motion control method according to claim 1, characterized in that: The lateral acceleration threshold is the product of the initial limit value of the lateral acceleration and a predetermined coefficient, and the predetermined coefficient ranges from 0.6 to 1.

7. The vehicle motion control method according to claim 2, characterized in that: The attitude angle is the angle between the center line of the front of the vehicle and the center line of the current lane.

8. The vehicle motion control method according to claim 4, characterized in that: The sensing range of the vehicle sensing system is an angle range and / or a distance range within which the vehicle sensing system senses the vehicle's surroundings.

9. A vehicle motion control system, the vehicle motion control system comprising: A confirmation module (10) configured to confirm the existence of an S-curve scene in the road ahead; A control module (20) is configured to adjust a lateral acceleration limit value when a steering wheel reverse is detected and the current lateral acceleration of the vehicle is greater than a lateral acceleration threshold.

10. A computer program product, such as a machine-readable storage medium, comprising or storing computer program instructions, wherein the computer program is adapted to perform the vehicle motion control method according to any one of claims 1 to 8 when executed on a computer.

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