Vehicle speed control method, device, medium and vehicle

Abstract

The present disclosure relates to a vehicle speed control method, device, medium and vehicle, and relates to the technical field of vehicles, which can control the vehicle speed with a smaller adjustment torque when the change rate of the vehicle speed error reaches a threshold value, thereby avoiding overshoot. The vehicle speed control method can include: obtaining an actual vehicle speed of a vehicle. Calculating a vehicle speed error between the actual vehicle speed and a target vehicle speed of the vehicle, wherein the vehicle speed error is used to obtain a lookup integral coefficient and a proportional coefficient from a PI coefficient mapping table. When the change rate of the vehicle speed error is less than or equal to a change rate threshold value, the vehicle speed is controlled with a first adjustment torque, wherein the first adjustment torque is smaller than a second adjustment torque obtained by proportional integral PI calculation based on the lookup integral coefficient and the proportional coefficient.

Description

Technical Field

[0001] This disclosure relates to the field of vehicle technology, and more specifically, to a vehicle speed control method, device, medium, and vehicle. Background Technology

[0002] The cruise control function of new energy vehicles can be implemented using the proportional-integral control (PI control) algorithm. The PI control algorithm uses the speed error between the target vehicle speed and the actual vehicle speed to query parameters.

[0003] When the target speed and the actual speed increase simultaneously, the speed error exhibits a dynamic characteristic of first increasing and then decreasing. During the speed error increase phase, the integral term continues to accumulate to a value far exceeding the actual requirement; while during the speed error decrease phase, the integral term cannot be released quickly, resulting in control lag and causing overshoot and other problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this disclosure provides a vehicle speed control method, device, medium, and vehicle that can solve the problem of vehicle overshoot.

[0005] To achieve the above objectives, in a first aspect, this disclosure provides a vehicle speed control method, the method comprising: Obtain the vehicle's actual speed; Calculate the speed error between the actual vehicle speed and the target vehicle speed, wherein the speed error is used to obtain the lookup integral coefficient and proportional coefficient from the PI coefficient mapping table; When the rate of change of the vehicle speed error is less than or equal to the rate of change threshold, the vehicle speed is controlled by a first adjusting torque, wherein the first adjusting torque is less than the second adjusting torque calculated by proportional integral PI based on the lookup table integral coefficient and the proportional coefficient.

[0006] Secondly, this disclosure provides a vehicle speed control device, the device comprising: The vehicle speed acquisition module is used to acquire the actual vehicle speed. An error calculation module is used to calculate the speed error between the actual vehicle speed and the target vehicle speed, wherein the speed error is used to obtain the lookup integral coefficient and proportional coefficient from the PI coefficient mapping table. The vehicle speed control module is used to control the vehicle speed with a first regulating torque when the rate of change of the vehicle speed error is less than or equal to a rate of change threshold, wherein the first regulating torque is less than the second regulating torque calculated by proportional-integral (PI) based on the lookup table integral coefficient and the proportional coefficient.

[0007] Thirdly, this disclosure provides a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method described in the first aspect.

[0008] Fourthly, this disclosure provides a vehicle, including: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the method described in the first aspect.

[0009] Fifthly, this disclosure provides a computer program product, including a computer program that, when executed by a processor, implements the method described in the first aspect.

[0010] In a sixth aspect, this disclosure provides a vehicle speed control device for use in a vehicle, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program implementing the method described in the first aspect when executed by the processor.

[0011] Through the above technical solution, when the rate of change of vehicle speed error is less than or equal to the rate of change threshold, the vehicle speed is controlled by a first adjusting torque that is less than the second adjusting torque. The second adjusting torque is calculated by a PI control algorithm using the integral and proportional coefficients obtained from a lookup table based on the vehicle speed error. The rate of change of vehicle speed error is used to determine the speed error descent phase. During this descent phase, the vehicle is adjusted with an adjusting torque less than the coefficients calculated from the lookup table, thus achieving reasonable speed regulation and avoiding overshoot.

[0012] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0013] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating a vehicle speed control method according to an exemplary embodiment of the present disclosure.

[0014] Figure 2 It is a linear schematic diagram illustrating the changing trend of various parameters according to an exemplary embodiment of this disclosure.

[0015] Figure 3 This is another flowchart illustrating a vehicle speed control method according to an exemplary embodiment of the present disclosure.

[0016] Figure 4This is a block diagram of a vehicle speed control device according to an exemplary embodiment of the present disclosure.

[0017] Figure 5 This is a block diagram of a vehicle according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0018] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0019] Cruise Control System (CCS) allows a vehicle to automatically maintain a constant speed without the driver needing to press the accelerator pedal. CCS uses a PI control algorithm to adjust torque, thereby controlling vehicle speed. Specifically, the PI control algorithm uses the speed difference between the target speed and the actual speed to look up the P / I coefficient mapping (MAP) table to obtain the proportional coefficient K corresponding to the speed difference. p and K i Then the proportionality coefficient K p and the integral coefficient K from the table i Substitute into the output formula of the PI controller PI calculations are performed. Here, u(t) represents the output signal of the PI controller; e(t) represents the error signal; K... p K represents the scaling factor, used to determine the strength of the response to the current error; i This represents the lookup table integral coefficient, used to determine the strength of the response to accumulated errors; The error integral (or error cumulative sum) represents the time from 0 to t, and the PI total torque (equivalent to the adjustment torque) is calculated. The actual vehicle speed is adjusted based on the PI total torque.

[0020] The inventors discovered that the I term in the above output formula will continue to accumulate torque until the actual vehicle speed equals the target vehicle speed. However, at this point, the accumulated torque of the I term is at its highest level, which is much greater than the torque required to stabilize the target vehicle speed. Therefore, the vehicle speed will continue to increase, resulting in an overshoot problem.

[0021] In view of this, the present disclosure provides a vehicle speed control method, device, medium and vehicle. When the vehicle is using cruise control, especially when the cruise control is activated by pressing and holding the acceleration and deceleration button and when waiting for the cruise control to resume, if the rate of change of the vehicle speed error meets the conditions, the torque calculated based on PI can be adjusted to control the vehicle speed at a lower torque than the calculated torque to avoid overshoot.

[0022] Figure 1This is a flowchart illustrating a vehicle speed control method according to an exemplary embodiment of this disclosure. This vehicle speed control method can be used with any type of vehicle, such as a hybrid vehicle, a non-hybrid vehicle, an electric vehicle, a fuel cell vehicle, or other types of vehicles. This vehicle speed control method can also be used with a vehicle speed control system, which can be installed on the vehicle to control the vehicle speed. Figure 1 As shown, the vehicle speed control method may include the following steps: In step S101, the actual vehicle speed is obtained.

[0023] In some embodiments, the actual vehicle speed refers to the instantaneous speed at which the vehicle is currently traveling, which can be measured by a vehicle speed sensor. In this step, acquiring the actual vehicle speed can refer to real-time acquisition of the actual vehicle speed, or it can refer to real-time reception of the actual vehicle speed transmitted by other devices. For example, when the vehicle speed control system or the vehicle is equipped with a vehicle speed sensor, step S101 can be understood as the vehicle speed control system or the vehicle acquiring the vehicle's actual vehicle speed in real time. As another example, when the vehicle speed control system is not equipped with a vehicle speed sensor, step S101 can be understood as the vehicle speed control system receiving the actual vehicle speed transmitted by the vehicle speed sensor on the vehicle in real time.

[0024] In step S102, the speed error between the actual vehicle speed and the target vehicle speed is calculated, wherein the speed error is used to obtain the lookup integral coefficient and proportional coefficient from the PI coefficient mapping table.

[0025] The target speed can be the actual speed of the vehicle in front; alternatively, it can be a desired speed set for the vehicle, which can be set by the driver or by the CCS (Carrier Controller System). The speed error is the difference between the actual speed and the target speed, and can be the actual speed minus the target speed. The PI coefficient mapping table can be a preset table in the PI controller, containing the proportional coefficient K corresponding to different magnitudes of speed error. p and the integral coefficient K from the table i Therefore, based on the vehicle speed error, the corresponding proportional coefficient K can be looked up from the PI coefficient mapping table. p and the integral coefficient K from the table i .

[0026] It should be noted that in actual operation, the proportional coefficient K can be looked up from the PI coefficient mapping table based solely on the vehicle speed error. p Or look up the integral coefficient K in the table i For example, when determining that the integral coefficient of term I is a constant value, the proportional coefficient K can be looked up simply from the PI coefficient mapping table. p .

[0027] In step S103, when the rate of change of the vehicle speed error is less than or equal to the rate of change threshold, the vehicle speed is controlled by a first regulating torque, wherein the first regulating torque is less than the second regulating torque calculated by proportional integral PI based on the lookup table integral coefficient and the proportional coefficient.

[0028] The rate of change characterizes how quickly the vehicle speed error changes over time. A larger rate of change indicates a faster change in vehicle speed error; a smaller rate of change indicates a slower change in vehicle speed error. A positive rate of change indicates an increase in vehicle speed error, while a negative rate of change indicates a decrease in vehicle speed error.

[0029] The inventors discovered that when the target vehicle speed and the actual vehicle speed increase synchronously, the speed error and its related parameters exhibit a regular changing trend. For details, please refer to... Figure 2 , Figure 2 This is a linear schematic diagram illustrating the changing trends of various parameters according to an exemplary embodiment of this disclosure. Figure 2 In the diagram, L1 represents the vehicle speed error, L2 represents the vehicle speed, L3 represents the torque of the P-term, L4 represents the accumulated torque of the I-term, and L5 represents the first adjustment torque. The vertical axis of L1 first increases and then decreases, indicating that the vehicle speed error exhibits a dynamic characteristic of first increasing and then decreasing. The trend of L4 shows that during the increasing phase of the vehicle speed error, the accumulated torque of the I-term continues to accumulate to a value higher than the actual requirement; during the decreasing phase of the vehicle speed error, the accumulated torque of the I-term cannot be released quickly, resulting in the second adjustment torque directly obtained from the PI calculation being greater than the actual required torque. Therefore, during the decreasing phase of the vehicle speed error, the first adjustment torque is used as the torque to control the vehicle speed. The first adjustment torque is less than the second adjustment torque directly obtained from the PI calculation, thus the torque adjustment is more accurate, avoiding over-adjustment that could cause the actual vehicle speed to exceed the target speed.

[0030] It should be understood that in related technologies, the proportional coefficient K is obtained by directly looking up a table based on the vehicle speed error. p and the integral coefficient K from the table i The previous method did not consider that different rates of change of vehicle speed error would affect the cumulative torque of term I. However, this disclosure uses the relationship between the rate of change of vehicle speed error and a preset rate of change threshold to determine whether the vehicle speed error is in a decreasing phase. When the vehicle speed error is in a decreasing phase, the vehicle speed is controlled with a first adjustment torque lower than the coefficient calculated from the lookup table. This avoids excessive torque output due to integral saturation, effectively preventing speed overshoot or repeated oscillations and improving control stability.

[0031] In this disclosure, the calculation method of vehicle torque can be dynamically controlled based on a dynamic comparison between the rate of change of vehicle speed error and a rate of change threshold, thereby achieving fine-grained adjustment of vehicle speed control. Specifically, when the rate of change of vehicle speed error is less than or equal to the rate of change threshold, it indicates that the vehicle speed error is in a decreasing phase. At this time, a smaller first adjustment torque is used for control to avoid overshoot caused by continuing to apply a larger torque. As another example, the absolute value of the rate of change of vehicle speed error can also be compared with the absolute value of the rate of change threshold to determine whether the trend of vehicle speed error is decreasing. Specifically, when the rate of change of vehicle speed error is negative and the absolute value of the rate of change is greater than or equal to the absolute value of the rate of change threshold, the vehicle speed is controlled with a first adjustment torque. In one feasible implementation, both detection methods can be used simultaneously to more reliably identify the decreasing trend of vehicle speed error.

[0032] In this disclosure, the rate of change threshold is a calibrated value and can be set empirically. As an example, the steps for obtaining the rate of change threshold include: Select at least one rate of change of vehicle speed error during the decrease process after the vehicle speed error reaches its peak. The rate of change threshold is determined based on at least one rate of change.

[0033] For example, the rate of change threshold can be taken from the rate of change of the vehicle speed error during the decreasing phase of the vehicle testing phase. For instance, the rate of change of the vehicle speed error at a certain moment in the decreasing phase can be used as the rate of change threshold; or, for example, data processing operations such as averaging the rate of change of the vehicle speed error at multiple moments in the decreasing phase can be performed to obtain the rate of change threshold. This application does not limit the method of setting the rate of change threshold.

[0034] In this embodiment, a first adjusting torque is used as the control benchmark during the speed error reduction phase. This first adjusting torque is lower than the second adjusting torque calculated by the conventional PI algorithm, effectively solving the control lag and overshoot problems caused by excessive accumulation of the integral term (I term) in traditional PI control. Regarding control accuracy, this disclosure actively reduces the torque control intensity when the error is predicted to converge, allowing the vehicle speed to approach the target value more smoothly, thus improving control accuracy. In terms of energy consumption optimization, this disclosure reduces unnecessary torque output, avoiding energy waste caused by overcompensation and frequent actuator movements, thereby reducing losses.

[0035] To help those skilled in the art better understand the vehicle speed control method provided in this disclosure, the steps of the vehicle speed control method are described in detail below.

[0036] In one feasible implementation, the vehicle speed control method may further include: When the rate of change of vehicle speed error exceeds the rate of change threshold, the vehicle speed is controlled by the second regulating torque.

[0037] Specifically, if the rate of change of vehicle speed error is greater than the rate of change threshold, it indicates that the vehicle speed error is increasing rapidly. The PI controller uses the P term to respond quickly and the I term to gradually eliminate the steady-state error, so as to prevent the vehicle speed from deviating significantly from the target speed.

[0038] For example, if the vehicle encounters a steep slope and its actual speed drops rapidly, exceeding the rate of change threshold for the speed error, then the system switches to PI control using a first adjusting torque calculated from the integral and proportional coefficients obtained from a lookup table. The first adjusting torque is larger than the second adjusting torque, thus increasing the vehicle speed.

[0039] In one feasible implementation, before controlling the vehicle speed with the first regulating torque, the vehicle speed control method may further include: The proportional-integral (PI) calculation is performed based on the proportional coefficient and the fixed integral coefficient to obtain the first adjustment torque corresponding to the vehicle. The fixed integral coefficient is less than the lookup table integral coefficient.

[0040] For example, during the decrease phase of the vehicle speed error, the integral coefficient is no longer obtained from a table based on the vehicle speed error, but instead, a fixed integral coefficient K0 replaces the table-lookup integral coefficient K. i K0 is less than K i .

[0041] In some embodiments, K0 can be a preset fixed value, which can be continuously optimized during the testing phase to obtain a calibration value. Specifically, the calibration steps for the fixed integral coefficient include: The fixed integral coefficients to be set next are adjusted based on the cumulative acceleration rate of the integral calculated based on the fixed integral coefficients set this time. The fixed integral coefficients to be set next time decrease as the cumulative acceleration rate of the integral increases. When the cumulative integral rate meets the preset conditions, the calibration of the fixed integral coefficients is completed, and the fixed integral coefficients are obtained.

[0042] For example, the smaller K0 is, the greater the reduction in the accumulation rate of the I term in the PI calculation. Therefore, in real vehicle calibration, K0 decreases as the integral accumulation rate increases to slow down the accumulation rate of the I term. Specifically, when the vehicle speed error accumulates rapidly, K0 will dynamically decrease, thereby reducing the output increment of the integral term and avoiding torque overshoot or oscillation caused by the excessively rapid accumulation of the I term; conversely, when the vehicle speed error changes slowly, K0 maintains a large value to ensure that the vehicle speed error returns to zero.

[0043] On the one hand, real-vehicle calibration K0 can achieve a balance between rapid response and stability. On the other hand, real-vehicle calibration covers different environments, making the data obtained from calibration adaptable to environmental changes, and thus more reliable.

[0044] In some embodiments, the fixed integral coefficient refers to a value that does not change with the vehicle speed error relative to the lookup integral coefficient, and the value can be dynamically adjusted as long as it is less than the lookup integral coefficient.

[0045] The inventors discovered that the PI control algorithm directly calculates the PI based on the original vehicle speed error. When the driver presses the button, the vehicle speed error exhibits a fluctuating upward trend, causing fluctuations in the torque calculated based on the PI, resulting in poor overall vehicle comfort. Therefore, step S103 calculates the vehicle speed error between the actual vehicle speed and the vehicle's target speed, including: The difference between the actual vehicle speed and the target vehicle speed is filtered to obtain the vehicle speed error.

[0046] It's worth noting that filtering refers to removing noise or high-frequency fluctuations using filtering algorithms. Specifically, this involves calculating the difference between the actual vehicle speed and the target vehicle speed, filtering this difference, and outputting the filtered vehicle speed error. This filtered vehicle speed error serves as the input to the PI controller. Compared to the original vehicle speed error, the filtered error reduces the impact of noise on the stability of the PI control, thus resulting in better PI control performance.

[0047] Continue to refer to Figure 2 Before filtering, the vehicle speed error fluctuates, resulting in fluctuations in the adjusted torque calculated based on the vehicle speed error, leading to poor overall vehicle comfort. After filtering, the vehicle speed error and torque are stable, resulting in good overall vehicle comfort. Therefore, filtering can reduce the sensitivity of the PI controller to noise, avoid torque oscillation caused by error signal jitter, and bring a stable riding experience.

[0048] In one feasible implementation, filtering the difference between the actual vehicle speed and the target vehicle speed to obtain the vehicle speed error may include: The difference between the actual vehicle speed and the target vehicle speed is filtered using the first filtering method. The difference obtained by filtering is processed by the second filtering method. The first filtering method includes moving average filtering, and the second filtering method includes first-order low-pass filtering.

[0049] This implementation uses two types of filtering to perform mixed filtering on the difference, thereby suppressing noise in stages and achieving good filtering results. The choice between the two filtering methods can be optimized based on the noise characteristics and control requirements of the actual application scenario. For example, and not as a limitation, the first-stage filtering includes moving average filtering, median filtering, amplitude limiting filtering, weighted average filtering, etc.; the second-stage filtering includes second-order low-pass filtering, Kalman filtering, Fourier transform filtering, etc.

[0050] For example, high-frequency noise can be eliminated first by using a moving average filter, and then mid-to-high frequency fluctuations can be suppressed by using a first-order low-pass filter, while preserving the low-frequency trend of the difference. Since hybrid filtering can improve the noise processing effect, the PI controller adjustment effect is also more stable.

[0051] The following describes in detail the complete steps of the vehicle speed control method provided in this disclosure using one embodiment: during the vehicle's cruise control activation, especially during the cruise control acceleration / deceleration process and during the waiting period after entering cruise control, a dynamic integral separation strategy is activated.

[0052] The following is combined with Figure 3 The dynamic integral separation strategy is explained. For example... Figure 3 As shown, the vehicle speed control methods include: First, a hybrid filter is applied to the vehicle speed error to eliminate the fluctuations caused by button presses during speed adjustment. Specifically, a moving average filter is used to remove sharp-angle jitter, and then a first-order low-pass filter is used to smooth the error.

[0053] Then, the rate of change of the vehicle speed error after hybrid filtering is obtained by differentiating the error. Since the trend of error change is first rising and then falling, a rate of change 'a' (equivalent to the rate of change threshold mentioned above) is taken during the decline process after the vehicle speed error reaches its peak. At this time, the vehicle speed error e > 0. The actual vehicle speed is still close to the target speed, but there is no need to accumulate item I too quickly. Therefore, when When the integral coefficient is used, the normal lookup table value is no longer used; instead, a calibration value K0 is used to reduce the cumulative acceleration rate of the I term. For details on how the calibration value K0 is set, please refer to the above introduction to the actual vehicle calibration; it will not be repeated here.

[0054] Next, based on the vehicle speed error after hybrid filtering, the proportional coefficient K is looked up from the MAP table. p With the proportionality coefficient K p The first adjusting torque is calculated using a fixed integral coefficient K0.

[0055] In addition, when At that time, the proportional coefficient K is looked up from the MAP table based on the vehicle speed error after hybrid filtering. pand the integral coefficient K from the table i With the proportionality coefficient K p and the integral coefficient K from the table i Calculate the second adjusting torque.

[0056] This embodiment of the disclosure performs hybrid filtering on the vehicle speed error to remove the impact of fluctuations in the difference between the target vehicle speed and the actual vehicle speed caused by dynamic changes in the target vehicle speed. The vehicle speed error after hybrid filtering changes linearly, and the PI torque calculated based on this vehicle speed error is free from fluctuations, thus ensuring driving stability. Furthermore, in the dynamic integral separation strategy, the I-term integral accumulation rate is determined based on the rate of change of the vehicle speed error. Two I-term value strategies are used for the rising and falling phases of the vehicle speed error to reduce invalid I-term integrals and improve the accuracy of vehicle speed control.

[0057] Based on the same inventive concept, this disclosure also provides a vehicle speed control device, such as... Figure 4 As shown, the vehicle speed control device includes: Vehicle speed acquisition module 401 is used to acquire the actual vehicle speed; Error calculation module 402 is used to calculate the speed error between the actual vehicle speed and the target vehicle speed. The speed error is used to obtain the lookup integral coefficient and proportional coefficient from the PI coefficient mapping table. The vehicle speed control module 403 is used to control the vehicle speed with a first regulating torque when the rate of change of the vehicle speed error is less than or equal to the rate of change threshold. The first regulating torque is less than the second regulating torque calculated by proportional-integral (PI) based on the lookup table integral coefficient and the proportional coefficient.

[0058] In this embodiment, when the rate of change of the vehicle speed error is less than or equal to a threshold value, the vehicle speed is controlled by a first adjustment torque less than the second adjustment torque. The second adjustment torque is calculated by a PI control algorithm using the integral and proportional coefficients obtained from a lookup table based on the vehicle speed error. The rate of change of the vehicle speed error is used to determine the speed error descent phase. During this descent phase, the vehicle speed is adjusted using an adjustment torque less than the coefficients calculated from the lookup table, thereby achieving reasonable speed control and avoiding overshoot.

[0059] Optionally, the error calculation module 402 is used to filter the difference between the actual vehicle speed and the target vehicle speed to obtain the vehicle speed error.

[0060] Optionally, the error calculation module 402 is used to filter the difference between the actual vehicle speed and the target vehicle speed using a first filtering method. The difference obtained by filtering is processed by the second filtering method. The first filtering method includes moving average filtering, and the second filtering method includes first-order low-pass filtering.

[0061] Optionally, the vehicle speed control module 403 is used to control the vehicle speed through a second regulating torque when the rate of change of the vehicle speed error is greater than the rate of change threshold.

[0062] Regarding the vehicle speed control device in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0063] Based on the same inventive concept, this disclosure also provides a vehicle, including: A memory on which computer programs are stored; The processor is used to execute computer programs in memory to implement the vehicle speed control method described above.

[0064] In this embodiment, when the rate of change of the vehicle speed error is less than or equal to a threshold value, the vehicle speed is controlled by a first adjustment torque less than the second adjustment torque. The second adjustment torque is calculated by a PI control algorithm using the integral and proportional coefficients obtained from a lookup table based on the vehicle speed error. The rate of change of the vehicle speed error is used to determine the speed error descent phase. During this descent phase, the vehicle speed is adjusted using an adjustment torque less than the coefficients calculated from the lookup table, thereby achieving reasonable speed control and avoiding overshoot.

[0065] Figure 5 This is a block diagram illustrating a vehicle 500 according to an exemplary embodiment. For example, vehicle 500 can be a hybrid vehicle, a non-hybrid vehicle, an electric vehicle, a fuel cell vehicle, or other types of vehicle. Vehicle 500 can be an autonomous vehicle or a semi-autonomous vehicle.

[0066] Reference Figure 5 The vehicle 500 may include various subsystems, such as an infotainment system 510, a perception system 520, a decision control system 530, a drive system 540, and a computing platform 550. The vehicle 500 may also include more or fewer subsystems, and each subsystem may include multiple components. Furthermore, each subsystem and component of the vehicle 500 can be interconnected via wired or wireless means.

[0067] In some embodiments, the infotainment system 510 may include a communication system, an entertainment system, and a navigation system, etc.

[0068] The perception system 520 may include several sensors for sensing information about the environment surrounding the vehicle 500. For example, the perception system 520 may include a global positioning system (which may be a GPS system, a BeiDou system, or another positioning system), an inertial measurement unit (IMU), lidar, millimeter-wave radar, ultrasonic radar, and a camera device.

[0069] The decision control system 530 may include a computing system, a vehicle controller, a steering system, a throttle, and a braking system.

[0070] The drive system 540 may include components that provide powered motion to the vehicle 500. In one embodiment, the drive system 540 may include an engine, an energy source, a transmission system, and wheels. The engine may be one or a combination of internal combustion engines, electric motors, and compressed air engines. The engine is capable of converting energy provided by the energy source into mechanical energy.

[0071] Some or all of the functions of vehicle 500 are controlled by computing platform 550. Computing platform 550 may include at least one processor 551 and memory 552, and processor 551 may execute instructions 553 stored in memory 552.

[0072] The processor 551 can be any conventional processor, such as a commercially available CPU. The processor may also include graphics processing units (GPUs), field-programmable gate arrays (FPGAs), systems on chips (SoCs), application-specific integrated circuits (ASICs), or combinations thereof.

[0073] The memory 552 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0074] In addition to instruction 553, memory 552 can also store data, such as vehicle status information, engine coolant temperature, intake air temperature, preset heating temperature, and preset cooling temperature. The data stored in memory 552 can be used by computing platform 550.

[0075] In this embodiment of the disclosure, the processor 551 may execute instruction 553 to complete all or part of the steps of the above-described vehicle speed control method.

[0076] In another exemplary embodiment, a computer-readable storage medium including program instructions is also provided, which, when executed by a processor, implement the steps of the vehicle speed control method described above. For example, the computer-readable storage medium may be the memory 552 including the program instructions, which may be executed by the processor 551 of the vehicle 500 to complete the vehicle speed control method described above.

[0077] In another exemplary embodiment, a computer program product is also provided, which includes a computer program executable by a programmable device, the computer program having a code portion for performing the above-described vehicle speed control method when executed by the programmable device.

[0078] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0079] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0080] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A vehicle speed control method, characterized in that, The method includes: Obtain the vehicle's actual speed; Calculate the speed error between the actual vehicle speed and the target vehicle speed, wherein the speed error is used to obtain the lookup integral coefficient and proportional coefficient from the PI coefficient mapping table; When the rate of change of the vehicle speed error is less than or equal to the rate of change threshold, the vehicle speed is controlled by a first adjusting torque, wherein the first adjusting torque is less than the second adjusting torque calculated by proportional integral PI based on the lookup table integral coefficient and the proportional coefficient; the step of obtaining the rate of change threshold includes: selecting at least one rate of change of the vehicle speed error during the decrease process after the vehicle speed error reaches its peak; and determining the rate of change threshold based on the at least one rate of change.

2. The vehicle speed control method according to claim 1, characterized in that, Before controlling the vehicle speed with the first adjusting torque, the method further includes: Based on the proportional coefficient and the fixed integral coefficient, a proportional-integral (PI) calculation is performed to obtain the first adjustment torque corresponding to the vehicle, wherein the fixed integral coefficient is less than the lookup table integral coefficient.

3. The vehicle speed control method according to claim 2, characterized in that, The calibration steps for the fixed integral coefficients include: The fixed integral coefficients to be set next are adjusted based on the cumulative integral rate calculated based on the fixed integral coefficients set this time, wherein the fixed integral coefficients to be set next decrease as the cumulative integral rate increases. When the integral accumulator rate meets the preset conditions, the calibration of the fixed integral coefficients is completed, and the fixed integral coefficients are obtained.

4. The vehicle speed control method according to claim 1, characterized in that, The method further includes: When the rate of change of the vehicle speed error exceeds the rate of change threshold, the vehicle speed is controlled by the second regulating torque.

5. The vehicle speed control method according to any one of claims 1-4, characterized in that, The calculation of the speed error between the actual vehicle speed and the target vehicle speed includes: The difference between the actual vehicle speed and the target vehicle speed is filtered to obtain the vehicle speed error.

6. The vehicle speed control method according to claim 5, characterized in that, The step of filtering the difference between the actual vehicle speed and the target vehicle speed to obtain the vehicle speed error includes: The difference between the actual vehicle speed and the target vehicle speed is filtered using the first filtering method. The difference obtained by filtering is processed by the second filtering method. The first filtering method includes moving average filtering, and the second filtering method includes first-order low-pass filtering.

7. A vehicle speed control device, characterized in that, The device includes: The vehicle speed acquisition module is used to acquire the actual vehicle speed. An error calculation module is used to calculate the speed error between the actual vehicle speed and the target vehicle speed, wherein the speed error is used to obtain the lookup integral coefficient and proportional coefficient from the PI coefficient mapping table. A vehicle speed control module is used to control the vehicle speed with a first regulating torque when the rate of change of the vehicle speed error is less than or equal to a rate of change threshold, wherein the first regulating torque is less than a second regulating torque calculated by proportional-integral (PI) based on the lookup table integral coefficient and the proportional coefficient; the step of obtaining the rate of change threshold includes: selecting at least one rate of change of the vehicle speed error during the decrease process after the vehicle speed error reaches its peak; and determining the rate of change threshold based on the at least one rate of change.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 6.

9. A vehicle, characterized in that, include: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the method of any one of claims 1 to 6.

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