A lateral control strategy for low-speed stopping and starting

Abstract

This invention discloses a lateral control strategy for low-speed following, stopping, and starting. By combining the longitudinal control ACC state, the system utilizes the vehicle state provided by ACC during longitudinal vehicle control to identify vehicle following, stopping, and starting. Then, it optimizes the lateral LCK control function and comprehensively considers the stability of lateral control at low speeds, as well as the motion parameters of the vehicle in front, to achieve comprehensive lateral control of the vehicle and achieve ideal results. At the same time, it increases the vehicle's intelligence, making it more convenient to operate when following other vehicles on urban roads and crossing traffic light intersections.

Description

Technical Field

[0001] This invention belongs to the field of vehicle control, and particularly relates to a lateral control strategy for low-speed stopping and starting. Background Technology

[0002] With the development of automotive technology, driver assistance functions are becoming increasingly common. Lateral vehicle control is crucial for stabilizing lateral movement and reducing driver workload; Lane Centering Control (LCK) is a frequently used function. Currently, the main state and transition logic of the mass-produced LCK algorithm are fixed, requiring Adaptive Cruise Control (ACC) to be activated before LCK is activated. ACC controls the vehicle's longitudinal speed and has multiple states.

[0003] The main states of ACC control are described below: Override means that when ACC is activated, the driver operates the accelerator pedal, and the depth of the accelerator pedal exceeds the accelerator pedal depth value requested by ACC, the vehicle responds to the driver's accelerator pedal operation; ON state means that when there is a target vehicle in front of the vehicle, and the speed set by the driver is greater than the speed of the target vehicle, ACC controls the vehicle to travel at the speed of the target vehicle; SpeedControl state means that when there is no target vehicle in front, or when there is a target vehicle ahead but the speed of the target vehicle ahead is greater than the cruise speed set by the driver, ACC controls the vehicle to travel at the set cruise speed; tempStop state means that ACC controls the vehicle to follow the target vehicle to a stop. When the target vehicle starts moving again, ACC controls the vehicle to start moving again to follow the target vehicle. The duration of tempStop is generally about 3 seconds. After this time, ACC will enter the Stop state; Stop state means that ACC controls the vehicle to follow the vehicle ahead to a stop. After the target vehicle moves away, the driver can press the accelerator pedal or operate the ACC system switch, and the ACC system will control the vehicle to resume following the target vehicle.

[0004] There are currently two strategies for lateral control of the LCK when the vehicle stops and starts: Scheme 1 is that when the ACC stops, the LCK retracts. After restarting the ACC, the LCK does not automatically activate. This is simple to operate, but when the driver stops and starts again at a red light or in traffic, the LCK needs to be reactivated, which is distracting and reduces convenience. Scheme 2 is that when the ACC stops, the LCK does not retract. No control value is output when the vehicle is stationary. The LCK resumes control when the ACC restarts. This scheme has the risk of the LCK activating when the vehicle is stationary. Speed ​​detection errors can cause the vehicle to turn in place and damage the steering system. When the ACC goes from Stop to Override, the LCK resumes control, which will interfere with the driver. Therefore, a lateral control strategy for low-speed stopping and starting is needed to solve the above problems. Summary of the Invention

[0005] To address the problems mentioned in the background art, the present invention provides a lateral control strategy for low-speed following, stopping, and starting.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a lateral control strategy for low-speed following, stopping, and starting, comprising the following steps:

[0007] Step 1: Obtain the target information output by the front-end sensing device and the vehicle information input by the vehicle;

[0008] Step 2: Based on the information in Step 1, the driver activates the ACC function and then operates the LCK switch. After the LCK determines that the lateral system meets the lateral activation conditions, the system is activated, calculates the torque or angle required for the desired lateral control under the current operating conditions, performs lateral control on the vehicle, and monitors the vehicle speed and the status of ACC.

[0009] Step 3: Based on the information in Step 2, when the vehicle speed is detected to be less than 0.5km / h, LCK will not output the requested torque or steering angle. When the ACC state is detected to enter the Stop state, the LCK function will exit and record this exit, while monitoring the ACC state.

[0010] Step 4: Based on the information in Step 3, when the ACC state is detected to be reactivated and enter the Override state, the LCK does not reactivate. When the ACC state changes from Override to On state, the LCK determines whether there are lane lines. If there are lane lines, it controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels within the lane lines.

[0011] Step 5: Based on the information in Step 3, when the ACC state is detected to be reactivated and enter the Override state, the LCK does not reactivate. When the ACC state changes from Override to On state, the LCK determines whether there are lane lines. When there are no lane lines, it uses the motion parameters of the preceding vehicle to fit a fifth-order polynomial. The fitted fifth-order polynomial is used to control the lateral movement of the vehicle to ensure that the vehicle follows the trajectory of the preceding vehicle.

[0012] Step 6: Based on the information in Step 3, when the ACC state is detected to be reactivated and the vehicle enters the Override state, the LCK does not reactivate. When the ACC state changes from Override to SpeedControl, the LCK determines whether there are lane lines. If there are lane lines, the LCK controls the vehicle's lateral movement according to the lane lines to ensure the vehicle stays within the lane lines. If the LCK determines that there are no lane lines, the LCK does not activate.

[0013] Step 7: Based on the information in Step 3, when the ACC state is detected to be reactivated and enter the ON state, LCK determines whether there are lane lines. If there are lane lines, it controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels within the lane lines.

[0014] Step 8: Based on the information in Step 3, when the ACC state is detected to be reactivated and enter the ON state, LCK determines whether there are lane lines. When there are no lane lines, the motion parameters of the preceding vehicle are used to fit a fifth-order polynomial. The fitted fifth-order polynomial is used to control the lateral movement of the vehicle to ensure that the vehicle follows the trajectory of the preceding vehicle.

[0015] Step 9: Based on the information in Step 3, when the ACC state is detected to be reactivated and the SpeedControl state is entered, LCK determines whether there are lane lines. If there are lane lines, it controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels within the lane lines. If there are no lane lines, LCK is not activated.

[0016] Step 10: Based on the information above, when the ACC status is detected to be exited, the LCK function will be deactivated and will not be automatically restored thereafter. When the driver needs the lateral LCK function, the LCK function switch needs to be pressed again to activate it.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. This invention improves lateral control performance by enhancing the smoothness of lateral control during the stopping and starting phases of intelligent driving vehicles and the safety at low speeds, while also improving the portability of the lateral control algorithm and its adaptability to different vehicle models.

[0019] 2. Improved driving experience: Enhanced vehicle comfort, making it easier for drivers to follow the vehicle in front at traffic lights and in congested areas, making operation more convenient, reducing driving stress, and the LCK function can be automatically restored after starting, making the driver assistance function more intelligent and increasing driving pleasure.

[0020] 3. Optimize control algorithms: Improve the robustness and real-time performance of longitudinal control algorithms, which will help increase public trust and acceptance of intelligent driving. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0022] Figure 1 This is a flowchart of the overall lateral control strategy for low-speed following, stopping, and starting;

[0023] Figure 2 The process of this invention Figure 2 ;

[0024] Figure 3 The process of this invention Figure 3 . Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] First, refer to Figures 1 to 3 A detailed description of a lateral control strategy for low-speed stopping and starting related to an embodiment of the present invention will be provided.

[0027] Step 1: Acquire the forward target information output by sensing devices such as cameras and millimeter-wave radar, and the vehicle information input by the vehicle itself;

[0028] Step 2: Based on the information in Step 1, the driver activates the ACC function and then operates the LCK switch. After the LCK determines that the lateral system meets the lateral activation conditions, the system is activated, calculates the torque or angle required for the desired lateral control under the current operating conditions, performs lateral control on the vehicle, and monitors the vehicle speed and the status of ACC.

[0029] Step 3: Based on the information in Step 2, when the vehicle speed is detected to be less than 0.5km / h, LCK will not output the requested torque or steering angle. When the ACC state is detected to enter the Stop state, the LCK function will exit and record this exit, while monitoring the ACC state.

[0030] Step 4: Based on the information in Step 3, when the ACC state is detected to be reactivated and enter the Override state, the LCK does not reactivate. When the ACC state changes from Override to On state, the LCK determines whether there are lane lines. If there are lane lines, it controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels within the lane lines.

[0031] Step 5: Based on the information in Step 3, when the ACC state is detected to be reactivated and enter the Override state, the LCK does not reactivate. When the ACC state changes from Override to On state, the LCK determines whether there are lane lines. When there are no lane lines, it uses the motion parameters of the preceding vehicle to fit a fifth-order polynomial. The fitted fifth-order polynomial is used to control the lateral movement of the vehicle to ensure that the vehicle follows the trajectory of the preceding vehicle.

[0032] Step 6: Based on the information in Step 3, when the ACC state is detected to be reactivated and the vehicle enters the Override state, the LCK does not reactivate. When the ACC state changes from Override to SpeedControl, the LCK determines whether there are lane lines. If there are lane lines, the LCK controls the vehicle's lateral movement according to the lane lines to ensure the vehicle stays within the lane lines. If the LCK determines that there are no lane lines, the LCK does not activate.

[0033] Step 7: Based on the information in Step 3, when the ACC state is detected to be reactivated and enter the ON state, LCK determines whether there are lane lines. If there are lane lines, it controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels within the lane lines.

[0034] Step 8: Based on the information in Step 3, when the ACC state is detected to be reactivated and enter the ON state, LCK determines whether there are lane lines. When there are no lane lines, the motion parameters of the preceding vehicle are used to fit a fifth-order polynomial. The fitted fifth-order polynomial is used to control the lateral movement of the vehicle to ensure that the vehicle follows the trajectory of the preceding vehicle.

[0035] Step 9: Based on the information in Step 3, when the ACC state is detected to be reactivated and the SpeedControl state is entered, LCK determines whether there are lane lines. If there are lane lines, it controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels within the lane lines. If there are no lane lines, LCK is not activated.

[0036] Step 10: Based on the information above, when the ACC status is detected to be exited, the LCK function will be deactivated and will not be automatically restored thereafter. When the driver needs the lateral LCK function, the LCK function switch needs to be pressed again to activate it.

[0037] To ensure the reliability and comfort of the lateral control disengagement process in the assisted driving system, this invention considers low-speed following and starting scenarios in LCK control. It ensures the intelligence of LCK control during low-speed following stops and the transition from stop to start, allowing the driver to effectively control the vehicle. Simultaneously, it meets the needs of drivers in urban areas with traffic lights and congested traffic where the vehicle needs to follow and stop the vehicle in front and then start again, without frequently activating the lateral control LCK function. LCK optimizes lateral control based on the vehicle's speed and the operating status of ACC (Adaptive Cruise Control).

[0038] Activating the LCK function requires meeting various conditions, the main ones of which are as follows:

[0039] The vehicle speed must meet the LCK activation conditions, and the speed range generally needs to be less than 120km / h, mainly to ensure vehicle safety.

[0040] If the lane markings meet the requirements, the vehicle needs to be in a lane with lane markings, or there is no lane markings but there is a target vehicle ahead. The ACC system controls the vehicle to follow the vehicle in front. The LCK can simulate the driving trajectory of the target vehicle ahead and use it as a lane marking for lateral control. The LCK controls the vehicle to follow the vehicle in front.

[0041] ACC function is activated. ACC is used for longitudinal control of the vehicle. LCK function is only allowed to be activated after ACC function is activated.

[0042] The vehicle must meet certain conditions, primarily including that the steering wheel angle is less than a certain angle, the turn signal is not activated, the brake pedal is not pressed, and the LCK-related systems are functioning correctly. The requirements may vary between companies, but the main purpose is to ensure the safety of lateral control and prevent lateral control from interfering with the driver's operation of the vehicle. When the driver has a strong intention to control the vehicle, the LCK function needs to be suppressed.

[0043] To enhance the safety and comfort of the lateral control function of the driver assistance controller during low-speed following and starting, this invention comprehensively considers the vehicle speed and the activation status of the ACC system to optimize the control of LCK, and considers disengaging and automatically resuming at appropriate times. The specific considerations are as follows:

[0044] Vehicle speed detection: For LCK speed detection, when the vehicle speed exceeds a certain value, typically above 120 km / h for a certain period, the LCK function will deactivate. When the vehicle speed is below 0.5 km / h, LCK remains active but no longer outputs requested lateral control torque or steering angle values ​​to prevent the vehicle from requesting lateral control while stationary, which could cause it to steer. LCK is only allowed to output lateral control torque or steering angle values ​​when the vehicle speed exceeds 0.6 km / h.

[0045] ACC Status Detection: When the ACC system transitions from active to Stop mode, the vehicle follows the vehicle in front to a stop. The ACC system maintains the vehicle at a complete stop, and the LCK function exits and records the exit status. When ACC reactivates from Stop, the LCK performs corresponding operations based on the following two scenarios: 1. If the ACC system remains in Stop mode for a period of time (generally 3 to 5 minutes, but this may vary depending on the company), the ACC system will exit Stop mode and enter an inactive state. 2. If the vehicle in front of the ACC system starts moving from a standstill, the ACC system can reactivate from Stop in two ways: one is when the driver presses the accelerator pedal, the ACC system reactivates and enters Override mode. In this case, the LCK clearly indicates the driver's intention to operate the vehicle, but it does not automatically reactivate; instead, it waits for the driver to relinquish control of the vehicle before automatically reactivating. 3. When the driver does not press the accelerator pedal, the ACC system enters On mode or SpeedControl mode. When LCK detects that ACC is in the On state, LCK returns to the active state and checks for lane markings. If lane markings exist, LCK controls the vehicle's lateral movement according to the lane markings, ensuring the vehicle stays in the center of the lane. If lane markings are absent, LCK fits a lane centerline based on the trajectory of the vehicle ahead and uses this fitted lane line to control the vehicle's lateral movement. When LCK detects that ACC is in SpeedControl state, it indicates that the vehicle ahead has been lost or the speed of the vehicle ahead exceeds the driver's set cruise speed. In this case, LCK checks for lane markings. If lane markings exist, LCK reactivates and controls the vehicle's lateral movement, keeping the vehicle in the center of the lane. If lane markings are absent, LCK is not allowed to automatically reactivate because there is no target vehicle ahead. Another method is for the driver to operate the ACC on / off switch to directly activate ACC, and the ACC system state directly changes from Stop to On or SpeedControl state. LCK determines that the driver has not intervened in vehicle control. Unlike the previous method where it waits in Override mode, LCK can directly enter active mode. When LCK detects that ACC is in On state, LCK returns to active mode and checks whether lane lines exist. When lane lines exist, LCK controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels in the center area of ​​the lane. When lane lines are not detected, LCK fits the lane center line based on the movement trajectory of the vehicle in front followed by ACC and uses the fitted lane line to control the vehicle's lateral movement.When LCK detects that ACC has entered SpeedControl mode, it means that the target vehicle ahead has been lost, or the speed of the vehicle ahead is greater than the cruise speed set by the driver. At this time, LCK checks whether the lane lines exist. When the lane lines exist, LCK is reactivated and controls the lateral movement of the vehicle to keep the vehicle in the center of the lane. When the lane lines are not detected, because there is no target vehicle ahead, LCK is not allowed to automatically resume.

[0046] ACC Function Deactivation Detection: When the ACC system is deactivated, the LCK function will not automatically reactivate. In the next cycle, after ACC is activated, if the driver wants to activate the lateral control function, they need to reactivate the LCK function switch. During the vehicle stop phase, the driver can deactivate the ACC function as needed, such as by pressing the brake pedal, or by pressing the ACC cancel or function exit button. Alternatively, if the ACC controls the vehicle to stop for longer than the maximum allowed Stop time, the ACC function will also deactivate.

[0047] Lane detection and processing when LCK is reactivated: When a vehicle is on an urban road, it follows the vehicle in front through a traffic light or intersection. While waiting at the traffic light, it will stop following the vehicle in front. After the vehicle in front starts moving, ACC is reactivated, and LCK is reactivated. Since there are no lane lines at the traffic light or intersection, the LCK system needs to fit a lane line based on the trajectory of the vehicle in front and the movement state of the vehicle itself. In this invention, a fifth-order polynomial is used to fit the lane center line. The algorithm for the lane line during the vehicle's starting phase will be explained in detail later.

[0048] LCK function status detection: When the vehicle is in a stop-and-go phase, LCK also detects the LCK system's conditions. When the LCK function exit conditions are met, LCK remains in the exit state. During this cycle, LCK will not automatically return to the active state. The driver needs to operate the LCK function switch again to reactivate the LCK function. The LCK exit conditions include, but are not limited to, the driver pressing the brake pedal, pulling the handbrake, and related system EPS, camera malfunction or obstruction, etc.

[0049] The following section focuses on using the vehicle's motion parameters and those of the vehicle following ahead to fit a fifth-order polynomial to the lane centerline. The LCK (Lane Centering Kinematics Control) uses this fitted centerline to control the vehicle's movement along the trajectory of the target vehicle. This ensures the vehicle follows the movement trend of the vehicle in front. ACC (Adaptive Cruise Control) controls the vehicle's longitudinal speed, and LCK controls its lateral movement. This ensures that when crossing traffic lights, the vehicle follows the vehicle ahead, stopping and restarting before passing through the intersection. The start and end points of the fifth-order polynomial can be set as follows: the start point is the vehicle's origin, whose parameters can be obtained from the vehicle's sensors; the end point is the rear bumper center point of the target vehicle.

[0050] Fifth-degree polynomial: f(x) = C0 + C1x + C2x 2 +C3x 3 +C4x 4 +C5x 5 (1)

[0051] Differentiate with respect to x: f'(x) = C1 + 2C2x + 3C3x 2 +4C4x 3 +5C5x 4 (2)

[0052] Find the second derivative with respect to x: f' ‘ (x) = 2C² + 6C³x + 12C⁴x 2 +20x 3 (3)

[0053] When x = 0, substituting the motion parameters at the origin of the vehicle, we get:

[0054] f(0)=C0=y0=0 (4)

[0055] f'(0)=C1=v y0 (5)

[0056] f(0)=2C2=a y0 (6)

[0057] Where y0 represents the lateral position error of the vehicle, and the starting point of the vehicle's motion planning is the current point of the vehicle, so it is equal to 0;

[0058] For v y0 This represents the vehicle's lateral speed, a value that can be obtained through the vehicle's sensors.

[0059] For a y0 This represents the vehicle's lateral acceleration, a value that can also be obtained through the vehicle's sensors.

[0060] When x = x pAt this point, point p represents the motion parameter of the rear center point of the vehicle ahead. Setting point p as the rear center point of the preceding vehicle, and using it as the endpoint of the fifth-order polynomial lane line, LCK can control the vehicle to move from its current position to the corresponding lateral position of the preceding vehicle, thus following its movement. Substituting the relevant motion parameters into the fifth-order polynomial, calculating the first and second derivatives, and then substituting them into x = x... p :

[0061]

[0062] Differentiate with respect to x:

[0063] Find the second derivative with respect to x:

[0064] Where y p The lateral position representing the center of the rear bumper of the target vehicle ahead;

[0065] For v yp The lateral velocity representing the center of the rear bumper of the target vehicle ahead;

[0066] For a yp The lateral acceleration representing the center of the rear bumper of the target vehicle ahead;

[0067] These three values ​​can all be obtained by testing with sensors such as cameras or front millimeter-wave radar.

[0068] Solving equations (4), (5), (6), (7), (8), and (9) simultaneously yields C3, C4, and C5, as shown below:

[0069]

[0070] Then, the obtained parameters C0, C1, C2, C3, C4, and C5 are substituted into the above equation (1) as the control lane line of the lateral LCK. The LCK controls the vehicle to drive according to the fitted fifth-order polynomial. Starting from the current position of the vehicle, it moves to the target vehicle in front and reaches the same lateral position as the target vehicle in front. The lateral speed and lateral acceleration follow the vehicle in front perfectly after starting at the traffic light position and crossing the intersection. The control effect is quite ideal.

[0071] This invention combines the longitudinal control (ACC) state with the vehicle status provided by ACC during longitudinal vehicle control to identify vehicle following, stopping, and starting. It then optimizes the lateral control (LCK) function and comprehensively considers the stability of lateral control at low speeds, as well as the motion parameters of the vehicle in front, to achieve ideal lateral control of the vehicle. This also increases the vehicle's intelligence, making it easier to operate when following other vehicles on urban roads and crossing traffic lights.

[0072] After real-vehicle testing, in urban areas, when the vehicle follows the vehicle in front, with the ACC function activated, the LCK function for lateral control is also activated. When following the vehicle through areas with heavy traffic or at traffic light intersections, the vehicle in front may sometimes stop to wait for a traffic light or other congested traffic. In this case, the vehicle's ACC system will control the vehicle to stop. Once the LCK detects that the ACC has entered the stop-and-go state, the LCK function will deactivate and record this deactivation. When the driver determines that the vehicle in front has started moving and the vehicle can restart, the driver can activate the ACC system by pressing the accelerator pedal or operating the ACC function recovery switch to control the vehicle to start moving again. After the LCK detects this situation, if the ACC has been reactivated by the driver, the LCK will directly resume, using a lane line fitted by a fifth-order polynomial to control the vehicle to follow the vehicle in front. If the driver restarts the vehicle by controlling the accelerator pedal, the ACC system is reactivated. When the driver stops pressing the accelerator pedal, ACC takes control of the vehicle. LCK, detecting this situation, automatically reactivates. When lane markings are detected, the system uses them to center the vehicle. When there are no lane markings but a vehicle is following ahead, a virtual fifth-order polynomial is used to control the vehicle's movement. This algorithm effectively controls the vehicle in urban or congested areas. With ACC and LCK lateral control activated, the vehicle frequently follows the vehicle in front, stopping and starting with minimal manual intervention. This makes the vehicle's driver assistance functions more intelligent, reducing driver stress in urban and congested areas, making vehicle operation more convenient, and improving overall vehicle performance.

[0073] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A lateral control strategy for low-speed stopping and starting, characterized in that, Includes the following steps: The system acquires target information output from the front-end sensing device and vehicle information input from the vehicle itself, and activates longitudinal control ACC and lateral control LCK function. The LCK system detects the status of the ACC system. When the vehicle speed is less than 0.5 km / h or the ACC enters the Stop state, the LCK will handle it accordingly. That is, when the vehicle speed is less than 0.5 km / h, the requested torque or steering angle will not be output. When the ACC enters the Stop state, the LCK function will exit and record, while monitoring the ACC status. The Stop state means that the ACC controls the vehicle to stop following the vehicle in front. When the ACC state is reactivated and enters the Override state, the LCK does not reactivate. After entering the On state from the Override state, if there are lane lines, the vehicle is controlled laterally according to the lane lines. If there are no lane lines, the vehicle is controlled laterally by fitting a fifth-order polynomial using the motion parameters of the vehicle in front. The Override state means that when the ACC function is activated, the driver operates the accelerator pedal, and the depth of the accelerator pedal exceeds the accelerator pedal depth value requested by ACC, and the vehicle responds to the driver's accelerator pedal operation. ON state means that when there is a target vehicle in front of the vehicle, and the speed set by the driver is greater than the speed of the target vehicle in front, ACC controls the vehicle to travel at the speed of the target vehicle in front. When ACC transitions from Override to SpeedControl, if there are lane lines, the vehicle will be controlled laterally according to the lane lines. If there are no lane lines, LCK will not be activated. SpeedControl means that when there is no target vehicle in front, or when there is a target vehicle ahead but the speed of the target vehicle ahead is greater than the cruise speed set by the driver, ACC will control the vehicle to travel at the set cruise speed. When ACC mode is deactivated, LCK function is deactivated and will not automatically resume. The driver must press the LCK function switch again to activate it.

2. The lateral control strategy for low-speed stopping and starting according to claim 1, characterized in that, It also includes the following specific steps: Step 1: Obtain the target information output by the front-end sensing device and the vehicle information input by the vehicle; Step 2: Based on the information in Step 1, the driver activates the ACC function and then operates the LCK switch. After the LCK determines that the lateral system meets the lateral activation conditions, the system is activated, calculates the torque or angle required for the desired lateral control under the current operating conditions, performs lateral control on the vehicle, and monitors the vehicle speed and the status of ACC.

3. The lateral control strategy for low-speed following, stopping, and starting according to claim 2, characterized in that: Based on the information in step 2, when the vehicle speed is detected to be less than 0.5 km / h, LCK will not output the requested torque or steering angle. When the ACC state is detected to enter the Stop state, the LCK function will exit and record the exit, while monitoring the ACC state.

4. The lateral control strategy for low-speed stopping and starting according to claim 3, characterized in that: When the ACC state is detected to be reactivated and enter the Override state, the LCK does not reactivate. When the ACC state changes from the Override state to the On state, the LCK determines whether there are lane lines. If there are lane lines, it controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels within the lane lines.

5. The lateral control strategy for low-speed stopping and starting according to claim 4, characterized in that: When the ACC state is detected to be reactivated and enter the Override state, the LCK does not reactivate. When the ACC state changes from the Override state to the On state, the LCK determines whether there are lane lines. If there are no lane lines, it uses the motion parameters of the preceding vehicle to fit a fifth-order polynomial. The fitted fifth-order polynomial is used to control the vehicle's lateral movement to ensure that the vehicle follows the trajectory of the preceding vehicle.

6. The lateral control strategy for low-speed following, stopping, and starting according to claim 5, characterized in that: When the ACC state is detected to be reactivated and the vehicle enters the Override state, the LCK does not reactivate. When the ACC state changes from the Override state to the SpeedControl state, the LCK determines whether there are lane lines. If there are lane lines, the LCK controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels within the lane lines. If the LCK determines that there are no lane lines, the LCK does not activate.

7. The lateral control strategy for low-speed stopping and starting according to claim 6, characterized in that: When the ACC state is detected to be reactivated and enter the ON state, LCK determines whether there are lane lines. If there are no lane lines, it uses the motion parameters of the vehicle in front to fit a fifth-order polynomial. The fitted fifth-order polynomial is used to control the vehicle's lateral movement to ensure that the vehicle follows the trajectory of the vehicle in front.

8. The lateral control strategy for low-speed stopping and starting according to claim 7, characterized in that: When the ACC state is detected to be reactivated and the SpeedControl state is entered, LCK determines whether there are lane lines. If there are lane lines, it controls the vehicle's lateral movement according to the lane lines to ensure that the vehicle travels within the lane lines; if there are no lane lines, LCK is not activated.

9. A lateral control strategy for low-speed stopping and starting according to claim 8, characterized in that: When the ACC status is detected as exiting, the LCK function is deactivated and will not automatically resume thereafter. When the driver needs the lateral LCK function, the LCK function switch needs to be pressed again to activate it.

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