Method of speed control in driving assistance system
By employing a dynamic compensation algorithm in the driver assistance system, vehicle speed instability caused by actuator response deviation and other factors is eliminated, thereby improving the accuracy of vehicle speed control and enhancing driving comfort.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2026-03-10
AI Technical Summary
The unstable speed control in existing driver assistance systems results in a large deviation between the actual speed and the set speed, which may be caused by actuator errors, control algorithm limitations, mechanical differences, environmental factors, and software defects.
A dynamic compensation algorithm is adopted to eliminate actuator response deviation by determining a first adjustment speed and to determine a vehicle speed compensation value based on the actual vehicle speed difference, which is then provided to the vehicle motion controller as a second adjustment speed to eliminate or reduce other causes of unstable vehicle speed control.
It significantly improves the accuracy of vehicle speed control, reduces deviations, and enhances driving comfort and safety.
Smart Images
Figure CN121626115A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vehicle speed control, and more specifically, to a method for speed control in a driver assistance system, a computer program product, a computer-readable storage medium, and a domain controller. Background Technology
[0002] In driver assistance systems, speed setting allows drivers to preset vehicle speeds based on personal needs and road conditions. For example, adaptive cruise control (ACC) systems typically have cruise speed control functionality. When cruise speed control is activated, the driver can input or adjust a desired vehicle speed via the vehicle's control interface (such as buttons on the steering wheel or a touchscreen), thereby reducing driving workload while maintaining a certain speed, minimizing unnecessary acceleration and deceleration, and improving fuel efficiency.
[0003] In existing solutions, the user-defined speed Vsetspd is typically provided directly to the vehicle motion controller (VMC) for speed control. However, this speed control is not very stable, resulting in a large deviation between the actual vehicle speed and the set speed. Summary of the Invention
[0004] The inventors of this application have realized that there may be a variety of reasons for unstable vehicle speed control, including but not limited to: (1) actuator error: the throttle, transmission or other actuators may have manufacturing or aging errors, resulting in an inability to respond accurately to control signals; (2) control algorithm limitation: the control algorithm used may not be advanced enough or optimized for a specific speed range, resulting in insufficient control accuracy; (3) mechanical differences: different mechanical components of the vehicle (such as tires, engine, transmission system) may have differences, affecting the consistency of speed control; (4) environmental factors: road conditions (such as slope, coefficient of friction), wind resistance, temperature and other environmental factors may affect vehicle speed; (5) software defects: the control software may have defects or deficiencies, and fail to properly handle all driving scenarios, etc.
[0005] Based on the above understanding, the inventors of this application considered using a dynamic compensation algorithm to adjust the vehicle speed. First, a first adjustment speed is determined based on the user-set speed Vsetspd, which is used to eliminate the response deviation of the actuator. Then, based on the difference between the first adjustment speed and the actual vehicle speed, a vehicle speed compensation value is determined, and a second adjustment speed is then determined for the vehicle motion controller VMC, so as to eliminate or reduce other causes of unstable vehicle speed control as much as possible.
[0006] According to one aspect of this application, a method for speed control in a driver assistance system is provided, the method comprising: receiving a user-defined speed Vsetspd; determining a first adjustment speed based on the user-defined speed Vsetspd, the first adjustment speed being used to eliminate actuator response deviation; and determining a vehicle speed compensation value based on the difference between the first adjustment speed and an actual vehicle speed, and further determining a second adjustment speed to be provided to a vehicle motion controller (VMC), wherein the second adjustment speed is equal to the sum of the first adjustment speed and the vehicle speed compensation value.
[0007] As a supplement or replacement to the above scheme, in the above method, the first adjustment speed is equal to the user-set speed Vsetspd plus an offset value, and wherein the offset value is a calibration value that changes according to the speed segment in which the user-set speed Vsetspd is located.
[0008] As a supplement or replacement to the above scheme, in the above method, determining the vehicle speed compensation value based on the difference between the first adjustment speed and the actual vehicle speed includes: when the first adjustment speed is greater than the actual vehicle speed, determining the first index i based on the quotient of the difference and the first step length value; and retrieving the corresponding compensation value array1[i] from the first compensation array queue array1 as the vehicle speed compensation value based on the first index i.
[0009] As a supplement or replacement to the above scheme, in the above method, determining the vehicle speed compensation value based on the difference between the first adjustment speed and the actual vehicle speed further includes: when the first adjustment speed is less than the actual vehicle speed, determining the second index j based on the quotient of the difference and the second step value; and retrieving the corresponding compensation value array2[j] from the second compensation array queue array2 as the vehicle speed compensation value based on the second index j.
[0010] As a supplement or replacement to the above scheme, in the above method, the values in the first compensation array queue array1 and the second compensation array queue array2 are both adjustable values, which are determined based on actual vehicle testing.
[0011] As a supplement or replacement to the above scheme, in the above method, the vehicle motion controller (VMC) is configured to coordinate the various control systems of the vehicle to achieve the expected motion trajectory and behavior.
[0012] As a supplement or alternative to the above scheme, the above method is executed in an adaptive cruise control system (ACC) or a traffic jam assist system (TJA).
[0013] According to another aspect of this application, a computer program product is provided, comprising a computer program that, when executed by a processor, implements the method described above.
[0014] According to another aspect of this application, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the method described above.
[0015] According to another aspect of this application, a domain controller is provided, including a memory, a processor, and a computer program stored in the memory, the processor executing the computer program to perform the following steps: performing the speed control method as described above to determine a second adjustment speed based on a received user-set speed Vsetspd; and sending the second adjustment speed to a vehicle motion controller VMC.
[0016] The speed control scheme of this application determines a first adjustment speed based on a user-defined speed Vsetspd, which is used to eliminate actuator response deviations. Then, based on the difference between the first adjustment speed and the actual vehicle speed, a vehicle speed compensation value is determined, and subsequently, a second adjustment speed is provided to the vehicle motion controller (VMC) to minimize or eliminate other causes of unstable vehicle speed control. This dynamic compensation algorithm significantly improves the accuracy of vehicle speed control, reduces deviations, and enhances driving comfort. Attached Figure Description
[0017] The above and other objects and advantages of this application will become more fully clear from the following detailed description taken in conjunction with the accompanying drawings, wherein the same or similar elements are denoted by the same reference numerals.
[0018] Figure 1 A flowchart illustrating a method for speed control in a driver assistance system according to an embodiment of this application is shown.
[0019] Figure 2 A flowchart illustrating a method for speed control in a driver assistance system according to an embodiment of this application is shown; and
[0020] Figure 3 A schematic diagram of the structure of a domain controller according to an embodiment of this application is shown. Detailed Implementation
[0021] In the following, schemes for target selection in lane-changing scenarios using visual recognition according to various exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings.
[0022] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction.
[0023] Figure 1 A schematic flowchart of a speed control method 1000 in a driver assistance system according to an embodiment of this application is shown. Figure 1 As shown, the method 1000 includes the following steps:
[0024] In step S110, the user-defined speed Vsetspd is received;
[0025] In step S120, a first adjustment speed is determined based on the user-defined speed Vsetspd, the first adjustment speed being used to eliminate actuator response deviation; and
[0026] In step S130, a vehicle speed compensation value is determined based on the difference between the first adjustment speed and the actual vehicle speed, and a second adjustment speed is then determined to be provided to the vehicle motion controller (VMC), wherein the second adjustment speed is equal to the sum of the first adjustment speed and the vehicle speed compensation value.
[0027] In the following description, the speed control method 1000 in the driver assistance system will be primarily described in the application scenario of the adaptive cruise control system ACC. Those skilled in the art will understand that, in addition to the adaptive cruise control system ACC, the method 1000 can also be executed in other driver assistance systems, such as the traffic jam assist system TJA, and this application is not limiting in this regard.
[0028] In the context of this application, the term "Adaptive Cruise Control System (ACC)" also refers to the adaptive cruise control function, which sends commands to the actuator based on the driving status (e.g., distance and speed) of the target vehicle ahead and the vehicle itself, thereby determining whether to accelerate, decelerate, or disengage cruise control. In some embodiments, the adaptive cruise control system includes a cruise speed control function, the main purpose of which is to detect moving and static targets directly in front of the vehicle using sensor signals such as cameras and radar, control the vehicle's speed, and maintain a safe distance from the target vehicle. After the driver sets a speed, when there are no vehicles ahead, the vehicle will accelerate or decelerate to reach the set speed and maintain it. In this way, the Adaptive Cruise Control System (ACC) can not only significantly improve driving comfort and safety, but also effectively reduce driver fatigue during long-distance driving and in congested traffic.
[0029] In step S110, the user-set speed Vsetspd is received. In one embodiment, the driver or user inputs or selects the desired cruise speed via the vehicle's user interface (such as a lever on the instrument panel, steering wheel buttons, or a touchscreen). The Adaptive Cruise Control (ACC) system needs to verify that the user-input speed is within an acceptable range, including minimum and maximum speed limits. After verification, the user-set speed is transmitted from the input device to the vehicle's central control unit or domain controller. Furthermore, the currently set speed is displayed to the driver on the vehicle's instrument panel or information display screen to confirm that their input has been accepted by the system.
[0030] After receiving the user-defined speed Vsetspd, in step S120, a first adjustment speed is determined to eliminate actuator response deviation. In one embodiment, the first adjustment speed is equal to the user-defined speed Vsetspd plus an offset value, wherein the offset value is a calibration value that changes according to the speed segment in which the user-defined speed Vsetspd is located.
[0031] In the context of this application, the "first adjustment speed" is used to address inconsistencies in actuator response across different speed ranges. Specifically, the actuator's response to different speed ranges may deviate, potentially causing a discrepancy between the actual vehicle speed and the set speed. To eliminate this deviation, the system fine-tunes the set speed based on the characteristics of each speed range. This is achieved by adding or subtracting a specific offset to adjust the speed command, ensuring the actuator responds more accurately and reaches the desired speed. The exact value of this offset is typically determined based on the vehicle's response during the actual calibration process.
[0032] By adjusting the initial speed, the performance of the ACC system and the vehicle's handling stability are improved. Especially at different speed ranges, the ACC system can ensure that the vehicle follows the vehicle in front more smoothly or travels at the set speed. By finely adjusting the actuator response, unnecessary speed fluctuations caused by differences in actuator performance can be reduced, thereby improving ride comfort and driving safety.
[0033] In order to further eliminate or reduce other causes of unstable vehicle speed control, in step S130, a vehicle speed compensation value is determined based on the difference between the first adjustment speed and the actual vehicle speed, and then a second adjustment speed is determined to be provided to the vehicle motion controller (VMC), wherein the second adjustment speed is equal to the sum of the first adjustment speed and the vehicle speed compensation value.
[0034] In other words, in step S130, the difference between the first adjusted speed and the actual vehicle speed is calculated, and a vehicle speed compensation value is determined based on the difference and a predefined compensation strategy (e.g., possibly involving looking up compensation arrays such as the first compensation array queue array1 or the second compensation array queue array2). Next, the vehicle speed compensation value is added to the first adjusted speed to obtain the second adjusted speed. This second adjusted speed is the target speed provided to the vehicle motion controller (VMC). Finally, through a closed-loop control system, the actual vehicle speed is continuously monitored, and the second adjusted speed is adjusted as needed to ensure that the actual vehicle speed is as close as possible to the user-set speed.
[0035] Obtaining the actual vehicle speed is fundamental to vehicle motion control. In one embodiment, wheel speed sensors (such as Hall effect sensors or photoelectric sensors) are used to measure the rotational speed of the wheels, and the vehicle's electronic control unit (ECU) then calculates the vehicle speed. Furthermore, to improve accuracy, the wheel speed sensor data is typically calibrated and compensated by software to eliminate errors caused by factors such as tire wear, changes in tire pressure, and road surface inclination. In another embodiment, a Global Positioning System (GPS) can also provide real-time vehicle speed information, a method that is highly effective in determining the vehicle's actual speed under different road conditions.
[0036] In one embodiment, step S130 includes: when the first adjustment speed is greater than the actual vehicle speed, determining a first index i based on the quotient of the difference and the first step length value; and retrieving a corresponding compensation value array1[i] from the first compensation array queue array1 as the vehicle speed compensation value based on the first index i. In one embodiment, step S130 further includes: when the first adjustment speed is less than the actual vehicle speed, determining a second index j based on the quotient of the difference and the second step length value; and retrieving a corresponding compensation value array2[j] from the second compensation array queue array2 as the vehicle speed compensation value based on the second index j.
[0037] In one or more embodiments, the first index i is calculated by dividing the difference between the first adjusted speed and the actual vehicle speed by the first step length value and rounding down. Similarly, the second index j is calculated by dividing the absolute value of the difference between the first adjusted speed and the actual vehicle speed (which is less than 0) by the second step length value and rounding down. In the above example, both the first step length value and the second step length value are set to be greater than 0. It can be understood that the closer the first step length value and the second step length value are to 0, the more precise the speed adjustment (which can further reduce speed fluctuations), but at the same time, the more frequently the adjustment calculations are performed.
[0038] For example, suppose the first adjustment speed is 16.66667 m / s (60 kph), the actual vehicle speed is 16.38889 m / s (59 kph), the first step length is 0.1 m / s (0.36 kph), and the first compensation array queue is array1[i] = {0.05, 0.25, 0.40, 0.425, 0.475, 0.55, 0.65, 0.75, 0.85, 0.95, 1.05, 1.15, 1.25, 1.35}, where the unit is m / s. It is necessary to note that in the above compensation array queue, the value of i is an integer greater than or equal to 0. That is, when i = 0, array1[0] = 0.05; when i = 1, array1[1] = 0.25; when i = 2, array1[2] = 0.40, and so on.
[0039] Therefore, the first adjustment speed minus the actual vehicle speed equals 0.27778 m / s. Based on this difference and the first step length, the first index i = 2 can be obtained. The corresponding compensation value can be determined from the first compensation array queue as 0.40. Finally, the second adjustment speed provided to the vehicle motion controller (VMC) equals 16.66667 + 0.40 = 17.0667 m / s.
[0040] In the example given above, since the first adjustment speed is greater than the actual vehicle speed, the speed request (i.e., the second adjustment speed) finally provided to the vehicle motion controller is set to a value greater than the first adjustment speed, so that the actual vehicle speed can be greater and closer to the speed set by the user.
[0041] It is important to note that the values in both the first compensation array queue (array1) and the second compensation array queue (array2) are adjustable and can be determined based on real-vehicle testing to adapt to different driving conditions and actuator characteristics. Furthermore, the magnitudes of the first and second step lengths will affect the determination of the first index i and the second index j, respectively, thus influencing the selection of the compensation value. Therefore, in one or more embodiments, the first and second step lengths are determined based on the requirements of system response speed and control accuracy.
[0042] In one or more embodiments, the vehicle motion controller (VMC) adjusts the vehicle's throttle, brakes, etc., according to a second adjustment speed to control the vehicle's actual speed and is configured to achieve the desired motion trajectory and behavior by coordinating the various control systems of the vehicle.
[0043] Figure 2 A schematic flowchart of a speed control method 2000 in a driver assistance system according to an embodiment of this application is shown. Figure 2 As shown, the method 2000 includes:
[0044] In step S210, the user-defined speed Vsetspd is received;
[0045] In step S220, a first adjustment speed is determined based on the user-defined speed Vsetspd, and the first adjustment speed is used to eliminate the response deviation of the actuator;
[0046] In step S230, it is determined whether the first adjusted speed is greater than the actual vehicle speed; if so, step S240 is executed, otherwise step S250 is executed.
[0047] In step S240, when the first adjustment speed is greater than the actual vehicle speed, the second adjustment speed provided to the vehicle motion controller VMC is equal to the first adjustment speed plus the compensation value array1[i], where array1[] is the first compensation array queue (which can be adjusted according to the actual vehicle test), and i is the first index, which is determined according to the difference between the first adjustment speed and the actual vehicle speed.
[0048] In step S250, when the first adjustment speed is less than the actual vehicle speed, the second adjustment speed provided to the vehicle motion controller (VMC) is equal to the first adjustment speed plus the compensation value array2[j], where array2[] is the second compensation array queue (which can be adjusted according to actual vehicle testing), and j is the second index, which is determined based on the difference between the first adjustment speed and the actual vehicle speed.
[0049] although Figure 2As not shown in the figure, in one or more embodiments, after executing step S240 or step S250, step S230 is re-executed, that is, the actual vehicle speed is continued to be monitored, and the compensation value is adjusted as appropriate (step S240 or S250) to ensure that the actual speed of the vehicle is as close as possible to the speed set by the user.
[0050] Furthermore, those skilled in the art will readily understand that the speed control method 1000 or 2000 in a driving assistance system provided in one or more embodiments of this application can be implemented by a computer program. For example, the computer program is included in a computer program product, and when executed by a processor, it implements the speed control method 1000 or 2000 in a driving assistance system according to one or more embodiments of this application. As another example, when a computer-readable storage medium (e.g., a USB flash drive) storing the computer program is connected to a computer, running the computer program executes one or more embodiments of this application, the speed control method 1000 or 2000 in a driving assistance system.
[0051] refer to Figure 3 It shows a schematic diagram of the structure of a domain controller 3000 according to an embodiment of this application. Figure 3 As shown, the domain controller 3000 includes a memory 310 and a processor 320, on which a computer program is stored. In one embodiment, the processor 320 executes the computer program to perform the following functions or steps: executing the speed control method 1000 or 2000 as described above to determine a second adjustment speed based on a received user-set speed Vsetspd; and sending the second adjustment speed to the vehicle motion controller VMC, causing the vehicle motion controller VMC to adjust the vehicle's throttle, brakes, etc., according to this second adjustment speed to control the actual speed of the vehicle.
[0052] In summary, the speed control scheme of this application determines a first adjustment speed based on a user-defined speed Vsetspd, which is used to eliminate actuator response deviations. Then, based on the difference between the first adjustment speed and the actual vehicle speed, a vehicle speed compensation value is determined, and subsequently, a second adjustment speed is provided to the vehicle motion controller (VMC) to minimize or eliminate other causes of vehicle speed control instability. This dynamic compensation algorithm significantly improves the accuracy of vehicle speed control, reduces deviations, and enhances driving comfort.
[0053] The above examples primarily illustrate the speed control scheme of embodiments of this application. Although only some embodiments of this application have been described, those skilled in the art should understand that this application can be implemented in many other forms without departing from its spirit and scope. Therefore, the examples and embodiments shown are considered illustrative rather than restrictive, and this application may cover various modifications and substitutions without departing from the spirit and scope of this application as defined in the claims.
Claims
1. A method of speed control in a driver assistance system, characterized in that, The method comprises: receiving a user set speed Vsetspd; determining a first adjusted speed based on the user set speed Vsetspd, the first adjusted speed being used to eliminate response bias of an actuator; and determining a speed compensation value based on a difference between the first adjusted speed and an actual vehicle speed, and in turn determining a second adjusted speed provided to a vehicle motion controller VMC, wherein the second adjusted speed is equal to a sum of the first adjusted speed and the speed compensation value.
2. The method of claim 1, wherein, The first adjusted speed is equal to the user set speed Vsetspd plus an offset value, and wherein the offset value is a calibration value that varies according to a speed segment in which the user set speed Vsetspd is located.
3. The method of claim 1, wherein, Determining a speed compensation value based on a difference between the first adjusted speed and an actual vehicle speed comprises: when the first adjusted speed is greater than the actual vehicle speed, determining a first index i based on a quotient of the difference and a first step value; and retrieving a corresponding compensation value array1[i] from a first compensation array queue array1 as the speed compensation value based on the first index i.
4. The method of claim 1, wherein, Determining a speed compensation value based on a difference between the first adjusted speed and an actual vehicle speed further comprises: when the first adjusted speed is less than the actual vehicle speed, determining a second index j based on a quotient of the difference and a second step value; and retrieving a corresponding compensation value array2[j] from a second compensation array queue array2 as the speed compensation value based on the second index j.
5. The method of claim 3 or 4, wherein, The values in the first compensation array queue array1 and the second compensation array queue array2 are tunable values determined from real vehicle testing.
6. The method of claim 1, wherein, The vehicle motion controller VMC is configured to achieve a desired motion trajectory and behavior by coordinating various control systems of the vehicle.
7. The method of claim 1, wherein, The method is performed in an adaptive cruise control system ACC or a traffic jam assist system TJA.
8. A computer program product comprising a computer program, characterized in that, The computer program, which when executed by a processor, implements the method of any one of claims 1 to 7.
9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program, which when executed by a processor, implements the method of any one of claims 1 to 7.
10. A domain controller comprising a memory, a processor, and a computer program stored on the memory, wherein the computer program comprises instructions that, when executed by the processor, cause the domain controller to perform the method of any one of claims 1-9. The processor executes the computer program to implement the following steps: performing the method of speed control of any one of claims 1 to 7 to determine a second adjusted speed based on a received user set speed Vsetspd; and sending the second adjusted speed to a vehicle motion controller VMC. The processor executes the computer program to implement the following steps: performing the method of speed control of any one of claims 1 to 7 to determine a second adjusted speed based on a received user set speed Vsetspd; and sending the second adjusted speed to a vehicle motion controller VMC.