Vehicle speed closed-loop control method and system, vehicle and storage medium

Abstract

The invention provides a vehicle speed closed-loop control method and system, a vehicle and a storage medium, and relates to the technical field of automatic driving. According to the method, the PI controller and the dynamic sliding mode controller are combined, the critical integral value corresponding to the PI controller is restrained through the first sliding mode surface critical value corresponding to the dynamic sliding mode controller, excessive accumulation of the integral value in the PI controller is avoided, and overshoot in the vehicle speed closed-loop control process is reduced. Meanwhile, the first sliding mode surface critical value is calculated based on the first vehicle speed difference and the required acceleration, the critical integral value is reduced based on the first vehicle speed difference and the first sliding mode surface critical value, the target integral value is obtained, rapid convergence of the first vehicle speed difference is achieved, and the performance of the vehicle for rapidly responding to the target vehicle speed is improved.

Description

Technical Field

[0001] The present application relates to the field of unmanned driving technology, and in particular to a vehicle speed closed-loop control method, system, vehicle, and storage medium. Background Art

[0002] Currently, the control systems of autonomous logistics vehicles typically employ a layered architecture, with the Autonomous Control Unit (ACU) and the Chassis Domain Control Unit (CDCU) working in tandem. The ACU is responsible for planning the vehicle's route and target speed, while the CDCU executes the planned route and target speed instructions from the ACU.

[0003] In related technologies, the ACU sends a target speed command to the CDCU. Based on vehicle dynamics, the CDCU adjusts the motor torque to achieve closed-loop control of the target speed. Typically, the CDCU uses a proportional-integral (PI) controller to calculate the current required acceleration based on the deviation between the target and actual speeds. This is then used to achieve closed-loop control of the target speed.

[0004] However, the above-mentioned method of using a PI controller to perform closed-loop control on the target vehicle speed may have a large overshoot problem during the closed-loop control process of the vehicle speed, that is, the actual vehicle speed temporarily far exceeds the target vehicle speed. Summary of the Invention

[0005] The present application provides a vehicle speed closed-loop control method, system, vehicle and storage medium to solve the problem of large overshoot in the closed-loop control process of the vehicle speed using a PI controller to perform closed-loop control of the target vehicle speed in the related art.

[0006] In a first aspect, the present application provides a vehicle speed closed-loop control method, comprising: obtaining a first vehicle speed and a target vehicle speed of a target vehicle, wherein the first vehicle speed is the actual vehicle speed of the target vehicle at the current moment; determining a first vehicle speed difference and a required acceleration based on the first vehicle speed and the target vehicle speed; determining a first synovial face boundary value corresponding to a dynamic synovial controller and a critical integral value corresponding to a PI controller based on the first vehicle speed difference and the required acceleration; reducing the critical integral value based on the first vehicle speed difference and the first synovial face boundary value to obtain a target integral value; determining a target acceleration based on the target integral value, and controlling the target vehicle speed closed-loop based on the target acceleration.

[0007] In one possible implementation, a first synovial surface boundary value corresponding to the dynamic synovial controller and a critical integral value corresponding to the PI controller are determined based on the first vehicle speed difference and the required acceleration, including: inputting the first vehicle speed difference and the required acceleration into the dynamic synovial controller to determine whether the first vehicle speed difference enters the synovial surface; in response to the first vehicle speed difference entering the synovial surface, determining that the product of the required acceleration and the synovial surface coefficient corresponding to the dynamic synovial controller is the first synovial surface boundary value, and determining that the integral value corresponding to the PI controller outputting the required acceleration based on the first vehicle speed difference is the critical integral value.

[0008] In one possible implementation, the critical integral value is reduced according to the first vehicle speed difference and the first synovial membrane facing boundary value to obtain the target integral value, including: determining the quotient of the first vehicle speed difference and the first synovial membrane facing boundary value as the integral reset coefficient, and the integral reset coefficient is less than 1; according to the integral reset coefficient, the critical integral value is reduced to obtain the target integral value.

[0009] In one possible implementation, the critical integral value is reduced according to the integral reset coefficient to obtain a target integral value, including: determining whether the critical integral value is successfully reduced according to the first vehicle speed difference; if the critical integral value is successfully reduced, determining the product of the integral reset coefficient and the critical integral value as the target integral value; if the critical integral value fails to be reduced, determining half of the first vehicle speed difference as the second synovial membrane facing boundary value, and repeating the steps of reducing the critical integral value according to the first vehicle speed difference and the second synovial membrane facing boundary value until the critical integral value is successfully reduced.

[0010] In one possible implementation, determining whether the critical integral value is successfully reduced is based on the first vehicle speed difference, including: determining whether the first vehicle speed difference is less than or equal to 0; if the first vehicle speed difference is less than or equal to 0, determining that the critical integral value is successfully reduced; if the first vehicle speed difference is equal to the second vehicle speed difference, and the second vehicle speed difference remains unchanged within a preset time length, or if the first vehicle speed difference is less than the second vehicle speed difference, and the first vehicle speed difference is greater than the synovial face critical threshold, then determining that the critical integral value has failed to be reduced, the second vehicle speed difference is the difference between the second vehicle speed and the target vehicle speed, and the second vehicle speed is the actual vehicle speed corresponding to the target vehicle at the previous moment adjacent to the current moment.

[0011] In one possible implementation, a first vehicle speed difference and a required acceleration are determined based on a first vehicle speed and a target vehicle speed, including: calculating the difference between the first vehicle speed and the target vehicle speed as the first vehicle speed difference; determining a current proportional parameter and a current integral parameter corresponding to the PI controller based on a mapping relationship between a first error interval and PI controller parameters according to the first vehicle speed difference; determining a compensation proportional parameter and a compensation integral parameter corresponding to the PI controller according to the target vehicle speed based on a mapping relationship between a second error interval and PI controller parameters; compensating the current proportional parameter using the compensation proportional parameter to obtain a target proportional parameter; compensating the current integral parameter using the compensation integral parameter to obtain a target integral parameter; and the PI controller outputs the required acceleration based on the target proportional parameter and the target integral parameter according to the first vehicle speed difference.

[0012] In the second aspect, the present application provides a vehicle speed closed-loop control system, including: an autonomous driving control system and a chassis domain control system; the autonomous driving control system is used to send a target vehicle speed planning instruction to the chassis domain control system; the chassis domain control system is used to respond to the target vehicle speed planning instruction and execute the vehicle speed closed-loop control method provided in the first aspect above.

[0013] In a third aspect, the present application provides a chassis domain control system, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the vehicle speed closed-loop control method provided in the first aspect above.

[0014] In a fourth aspect, the present application provides a vehicle, comprising a vehicle speed closed-loop control system as provided in the second aspect above, or comprising a chassis domain control system as provided in the third aspect above.

[0015] In a fifth aspect, the present application provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed by a processor, they are used to implement the vehicle speed closed-loop control method provided in the first aspect above.

[0016] In a sixth aspect, the present application provides a computer program product, comprising: a computer program, which, when executed by a processor, implements the vehicle speed closed-loop control method provided in the first aspect above.

[0017] The vehicle speed closed-loop control method, system, vehicle, and storage medium provided in this application obtain the actual vehicle speed of the target vehicle at the current moment, namely the first vehicle speed, and the target vehicle speed, and determine the first vehicle speed difference and the required acceleration based on the first vehicle speed and the target vehicle speed. Furthermore, based on the first vehicle speed difference and the required acceleration, the first synovial face threshold value corresponding to the dynamic synovial controller and the critical integral value corresponding to the PI controller are determined. Then, based on the first vehicle speed difference and the first synovial face threshold value, the critical integral value is reduced to obtain the target integral value. Finally, based on the target integral value, the target acceleration is determined, and the target vehicle speed closed-loop is controlled based on the target acceleration. This application utilizes a combination of a PI controller and a dynamic synovial controller, constraining the critical integral value corresponding to the PI controller through the first synovial face threshold value corresponding to the dynamic synovial controller, thereby avoiding excessive accumulation of integral values ​​in the PI controller and reducing overshoot during the vehicle speed closed-loop control process. At the same time, by calculating the first synovial pressure limit value based on the first vehicle speed difference and the required acceleration, and reducing the critical integral value based on the first vehicle speed difference and the first synovial pressure limit value, the target integral value is obtained, thereby achieving rapid convergence of the first vehicle speed difference and improving the vehicle's performance in quickly responding to the target vehicle speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0019] Figure 1 A schematic diagram of the structure of a vehicle speed closed-loop control system provided in an embodiment of the present application;

[0020] Figure 2 Schematic diagram of the process of the vehicle speed closed-loop control method provided in the embodiment of the application Figure 1 ;

[0021] Figure 3 Schematic diagram of the process of the vehicle speed closed-loop control method provided in the embodiment of the application Figure 2 ;

[0022] Figure 4 Schematic diagram of the process of the vehicle speed closed-loop control method provided in the embodiment of the application Figure 3 ;

[0023] Figure 5 Schematic diagram of the process of the vehicle speed closed-loop control method provided in the embodiment of the application Figure 4 ;

[0024] Figure 6 A logic diagram of the closed-loop speed control of the vehicle provided in an embodiment of the present application;

[0025] Figure 7 A schematic structural diagram of a chassis domain control system provided in one embodiment of the present application.

[0026] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0027] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0028] In related technologies, the ACU sends a target speed command to the CDCU, which then adjusts the motor torque based on vehicle dynamics to achieve closed-loop control of the target speed. Typically, the CDCU uses a proportional integral (PI) controller to calculate the current required acceleration based on the deviation between the target speed and the actual speed, and further achieves closed-loop control of the target speed based on the current required acceleration. However, when the PI controller is used for closed-loop speed control, if the vehicle's response performance is to be ensured, the proportional (Kp) parameter or integral (Ki) parameter of the PI controller needs to be increased. However, if the proportional parameter or integral parameter is too large, the vehicle's weight, vehicle inertia, and other factors will cause the vehicle to have large overshoot and slow callback.

[0029] To address the challenges of related technologies, the present invention combines a PI controller with a dynamic sliding film controller. The dynamic sliding film controller's sliding film face threshold constrains the critical integral value of the PI controller, preventing excessive accumulation of integral values ​​in the PI controller and reducing overshoot during closed-loop speed control. Furthermore, by determining a first sliding film face threshold based on the speed difference between the actual and target speeds and the required acceleration, and then reducing the critical integral value based on the speed difference and the sliding film face threshold, the target integral value is obtained. Rapid convergence of the speed difference is achieved, improving the vehicle's ability to quickly respond to the target speed.

[0030] First, combine Figure 1 The vehicle speed closed-loop control system provided in the embodiment of the present application is described in detail.

[0031] Figure 1 This is a schematic diagram of the structure of the vehicle speed closed-loop control system provided in the embodiment of the present application. Figure 1As shown, the vehicle speed closed-loop control system provided in the embodiment of the present application includes an autonomous driving control system and a chassis domain control system.

[0032] Among them, the self-driving control system is used to send target vehicle speed planning instructions to the chassis domain control system;

[0033] The chassis domain control system is used to respond to the target vehicle speed planning instruction and execute the vehicle speed closed-loop control method provided in the embodiment of the present application.

[0034] The target vehicle speed is carried in the target vehicle speed planning instruction sent by the self-driving control system to the chassis domain control system.

[0035] Exemplarily, the autonomous driving control system and the chassis domain control system may be communicatively connected via a communication bus.

[0036] like Figure 1 As shown in , the chassis domain control system includes a PI controller and a dynamic sliding film controller. The chassis domain control system provided in the embodiment of the present application realizes closed-loop control of the target vehicle speed by combining the PI controller and the dynamic sliding film controller.

[0037] Below is Figure 1 The chassis domain control system shown in is the execution body, and the specific implementation method of the vehicle speed closed-loop control method provided in the embodiment of the present application is described in detail in combination with specific embodiments.

[0038] Figure 2 Schematic diagram of the process of the vehicle speed closed-loop control method provided in the embodiment of the application Figure 1 .like Figure 2 As shown, the specific implementation of the vehicle speed closed-loop control method includes the following steps:

[0039] S201: Acquire a first vehicle speed and a target vehicle speed of a target vehicle.

[0040] Exemplarily, the first vehicle speed is the actual vehicle speed of the target vehicle at the current moment.

[0041] For example, the target vehicle may be an unmanned logistics vehicle, etc.

[0042] For example, the first vehicle speed of the target vehicle can be obtained based on a wheel speed sensor, a global positioning system (GPS), an inertial measurement unit (IMU), etc. The embodiment of the present application does not specifically limit the method for obtaining the first vehicle speed, and the method can be determined based on actual application requirements.

[0043] For example, the target speed of the target vehicle can be Figure 1The self-driving control system shown in the figure is dynamically calculated based on factors such as route planning, traffic conditions, road conditions, and traffic regulations, and sent to the chassis domain control system.

[0044] S202: Determine a first vehicle speed difference and a required acceleration according to the first vehicle speed and the target vehicle speed.

[0045] In one possible implementation, the difference between the first vehicle speed and the target vehicle speed is determined as a first vehicle speed difference, and the first vehicle speed difference is input into a PI controller to obtain a required acceleration output by the PI controller. The proportional and integral parameters of the PI controller can be dynamically adjusted based on the first vehicle speed difference.

[0046] S203 : Determine a first synovial pressure limit value corresponding to the dynamic synovial pressure controller and a critical integral value corresponding to the PI controller according to the first vehicle speed difference and the required acceleration.

[0047] Illustratively, the first synovial surface threshold value may be a critical value corresponding to when the first vehicle speed difference enters the synovial surface.

[0048] Illustratively, the first synovial surface face threshold is determined according to the required acceleration and the synovial surface coefficient.

[0049] In a possible implementation, when the first vehicle speed difference enters the synovial surface, the product of the synovial surface coefficient and the required acceleration may be determined as the first synovial surface entry threshold value.

[0050] For example, the sliding surface coefficient is determined based on the target vehicle speed. For example, when the target vehicle speed is less than 2 km / h, the sliding surface coefficient is determined to be 1.2; when the target vehicle speed is between 2 km / h and 5 km / h, the sliding surface coefficient is determined to be 1.1; when the target vehicle speed is greater than 5 km / h, the sliding surface coefficient is determined to be 1, and so on.

[0051] For example, when the target vehicle speed is in a low speed range, such as less than 5 km / h, the sliding surface coefficient is negatively correlated with the target vehicle speed.

[0052] For example, the critical integral value corresponding to the PI controller may be an integral value output by the PI controller based on the integral parameter at the moment when the first vehicle speed difference enters the sliding surface.

[0053] S204: According to the first vehicle speed difference and the first synovial membrane face threshold value, the critical integral value is reduced to obtain a target integral value.

[0054] In a possible implementation, an integral reset coefficient may be determined according to the first vehicle speed difference and the first synovial contact threshold value, and the critical integral value may be reduced based on the integral reset coefficient to obtain a target integral value.

[0055] For example, the target integral value may be an integral value corresponding to when the PI controller outputs the target acceleration when controlling the target vehicle speed in a closed loop.

[0056] S205: Determine a target acceleration based on the target integral value, and control the target vehicle speed closed loop based on the target acceleration.

[0057] In one possible implementation, the first vehicle speed difference is input into a PI controller, so that the PI controller outputs a target acceleration based on the target integral value and the first vehicle speed difference. Then, the motor controller in the target vehicle uses a vehicle dynamics model to calculate the motor drive torque required to achieve the target acceleration according to the target acceleration, and outputs the motor drive torque by adjusting the current and voltage of the motor, thereby controlling the actual speed of the target vehicle to reach the target speed, that is, realizing a closed loop of the target speed.

[0058] For example, before the motor driving torque is output by adjusting the current and voltage of the motor, the motor driving torque calculated by the vehicle dynamics model may be filtered to achieve smoothing of the motor driving torque.

[0059] Exemplarily, the filter may be a low-pass filter.

[0060] In an embodiment of the present application, the actual speed of the target vehicle at the current moment, i.e., a first speed, and a target speed are obtained. Based on the first speed and the target speed, a first speed difference and a required acceleration are determined. Furthermore, based on the first speed difference and the required acceleration, a first synovial face threshold corresponding to a dynamic synovial controller and a critical integral value corresponding to a PI controller are determined. The critical integral value is then reduced based on the first speed difference and the first synovial face threshold to obtain a target integral value. Finally, based on the target integral value, a target acceleration is determined, and the target speed closed-loop control is performed based on the target acceleration. In an embodiment of the present application, a PI controller and a dynamic synovial controller are combined. The critical integral value corresponding to the PI controller is constrained by the first synovial face threshold corresponding to the dynamic synovial controller, thereby preventing excessive accumulation of integral values ​​in the PI controller and reducing overshoot during closed-loop speed control. Furthermore, by calculating the first synovial face threshold based on the first speed difference and the required acceleration, and reducing the critical integral value based on the first speed difference and the first synovial face threshold to obtain a target integral value, rapid convergence of the first speed difference is achieved, thereby improving the vehicle's ability to quickly respond to the target speed.

[0061] The following combination Figure 3 The specific implementation method of determining the first synovial membrane face threshold value corresponding to the dynamic synovial membrane controller and the critical integral value corresponding to the proportional-integral controller according to the first vehicle speed difference and the required acceleration in step S203 is described in detail.

[0062] Figure 3 Schematic diagram of the process of the vehicle speed closed-loop control method provided in the embodiment of the application Figure 2 .like Figure 3 As shown, in the vehicle speed closed-loop control method, a specific implementation method for determining the first sliding membrane face threshold value corresponding to the dynamic sliding membrane controller and the critical integral value corresponding to the proportional-integral controller according to the first vehicle speed difference and the required acceleration may include the following steps:

[0063] S301 : Inputting a first vehicle speed difference and a required acceleration into a dynamic sliding film controller to determine whether the first vehicle speed difference enters a sliding film surface.

[0064] Exemplarily, a synovial surface comparator is designed in the dynamic synovial controller.

[0065] In one possible implementation, the first vehicle speed difference and the required acceleration are input into a sliding membrane surface comparator in the dynamic sliding membrane controller. The sliding membrane surface comparator compares the first vehicle speed difference with the product of the required acceleration and the sliding membrane surface coefficient to determine whether the first vehicle speed difference enters the sliding membrane surface.

[0066] Exemplarily, when the first vehicle speed difference is less than the product of the required acceleration and the synovial surface coefficient, it is determined that the first vehicle speed difference enters the synovial surface; when the first vehicle speed difference is greater than or equal to the product of the required acceleration and the synovial surface coefficient, it is determined that the first vehicle speed difference does not enter the synovial surface.

[0067] In one possible implementation, when it is determined that the first vehicle speed difference enters the sliding surface, step S302 is executed; when it is determined that the first vehicle speed difference does not enter the sliding surface, the proportional parameter and the integral parameter in the PI controller are dynamically adjusted based on the first vehicle speed difference and the target vehicle speed, thereby adjusting the required acceleration output by the PI controller, and the adjusted required acceleration and the first vehicle speed difference are input into the sliding surface for comparison, and the sliding surface comparator compares the first vehicle speed difference with the product of the adjusted required acceleration and the sliding surface coefficient again, and repeats this process until the first vehicle speed difference enters the sliding surface, that is, the first vehicle speed difference is less than the product of the adjusted required acceleration and the sliding surface coefficient.

[0068] S302, in response to the first vehicle speed difference entering the synovial surface, determining that the product of the required acceleration and the synovial surface coefficient corresponding to the dynamic synovial controller is the first synovial surface boundary value, and determining that the integral value corresponding to the proportional-integral controller outputting the required acceleration according to the first vehicle speed difference is the critical integral value.

[0069] In a possible implementation, in response to the first vehicle speed difference entering the synovial surface, the first synovial surface boundary value and the critical integral value are locked.

[0070] In an embodiment of the present application, by inputting the first vehicle speed difference and the required acceleration into a dynamic sliding film controller, it is determined whether the first vehicle speed difference enters the sliding film surface, and in response to the first vehicle speed difference entering the sliding film surface, the product of the required acceleration and the sliding film surface coefficient corresponding to the dynamic sliding film controller is determined as the first sliding film surface boundary value, and the integral value corresponding to the proportional-integral controller when outputting the required acceleration according to the first vehicle speed difference is determined to be the critical integral value. This can prevent the integral value in the PI controller from being too large to cause overshoot in advance, so that the first vehicle speed of the target vehicle can quickly converge near the target vehicle speed, thereby improving the vehicle's performance in quickly responding to the target vehicle speed.

[0071] The following combination Figure 4 A detailed description will be given of a specific implementation method for reducing the critical integral value and obtaining the target integral value according to the first vehicle speed difference and the first synovial membrane face threshold value in step S204.

[0072] Figure 4 Schematic diagram of the process of the vehicle speed closed-loop control method provided in the embodiment of the application Figure 3 .like Figure 4 As shown, in the vehicle speed closed-loop control method, a specific implementation method of reducing the critical integral value according to the first vehicle speed difference and the first synovial face critical value to obtain the target integral value may include the following steps:

[0073] S401: Determine the quotient of the first vehicle speed difference and the first synovial contact threshold as an integral reset coefficient, where the integral reset coefficient is less than 1.

[0074] Exemplarily, the integral reset coefficient is used to reduce the critical integral value.

[0075] Illustratively, the integral reset coefficient is used to update the integral part of a PI controller.

[0076] It is understandable that, during the closed-loop control of the target vehicle speed, as the first vehicle speed difference decreases, the integral reset coefficient will also decrease.

[0077] S402: Reduce the critical integral value according to the integral reset coefficient to obtain a target integral value.

[0078] Optionally, a possible implementation method may be: determining whether the critical integral value is successfully reduced based on the first vehicle speed difference; if the critical integral value is successfully reduced, determining the product of the integral reset coefficient and the critical integral value as the target integral value; if the critical integral value fails to be reduced, determining half of the first vehicle speed difference as the second synovial membrane facing boundary value, and repeating the steps of reducing the critical integral value based on the first vehicle speed difference and the second synovial membrane facing boundary value until the critical integral value is successfully reduced.

[0079] For example, when the critical integral value fails to be reduced, half of the first vehicle speed difference is determined as the second synovial surface critical value to achieve the reduction of the synovial surface.

[0080] Exemplarily, when the critical integral value fails to be reduced, half of the first speed difference is determined as the second synovial surface boundary value, and the product of the integral reset coefficient and the critical integral value is determined as the reset integral value. The PI controller outputs a reset acceleration based on the first speed difference and the reset integral value, and further obtains the current actual speed of the target vehicle based on the reset acceleration. The actual speed is less than the target speed. The current speed difference is calculated based on the actual speed and the target speed. The current speed difference is input into the synovial surface comparator to determine whether the current speed difference is less than the second synovial surface boundary value. When the current speed difference is less than the second synovial surface boundary value, the reset integral value is reduced according to the current speed difference and the second synovial surface boundary value until the reset integral value is successfully reduced.

[0081] In this embodiment of the present application, the quotient of the first vehicle speed difference and the first synovial contact threshold is determined as an integral reset coefficient, and the critical integral value is reduced based on the integral reset coefficient to obtain a target integral value. In this embodiment of the present application, by reducing the critical integral value based on the integral reset coefficient, smooth adjustment of the integral gain in the PI controller is achieved, thereby reducing vehicle speed oscillations in closed-loop vehicle speed control.

[0082] Optionally, a possible implementation method for determining whether the critical integral value has been successfully reduced based on the first speed difference may be: determining whether the first speed difference is less than or equal to 0; if the first speed difference is less than or equal to 0, determining that the critical integral value has been successfully reduced; if the first speed difference is equal to the second speed difference, and the second speed difference remains unchanged within a preset time length, or if the first speed difference is less than the second speed difference, and the first speed difference is greater than the synovial face critical threshold, then determining that the critical integral value has failed to be reduced, the second speed difference is the difference between the second speed and the target speed, and the second speed is the actual speed corresponding to the target vehicle at the previous moment adjacent to the current moment.

[0083] It should be noted that the embodiment of the present application does not limit the specific size of the synovial membrane face critical threshold, which can be determined according to actual application requirements.

[0084] For example, when the first speed difference is equal to 0, it means that the actual speed of the target vehicle at the current moment is the same as the target speed, that is, closed-loop control of the target speed is achieved; when the first speed difference is less than 0, it means that the actual speed of the target vehicle at the current moment is greater than the target speed, that is, closed-loop control of the target speed is achieved, and there is overshoot in the closed-loop control.

[0085] It should be noted that in the vehicle speed closed-loop control method provided in the embodiment of the present application, when the first differential difference is less than 0, the absolute value of the first differential difference is less than 0.5, that is, the overshoot in the closed-loop control of the target vehicle speed is small.

[0086] Exemplarily, the preset duration may be 300ms.

[0087] It can be understood that when the first speed difference is equal to the second speed difference and the second speed difference remains unchanged within a preset time period, it means that the speed difference between the actual speed of the target vehicle and the target speed has narrowed to a position midway between 0 and the current speed difference, and cannot be further reduced and remains at the current position.

[0088] For example, the target vehicle speed is 10 km / s, the first vehicle speed of the target vehicle at the current moment is 9.5 km / s, and the second vehicle speed of the target vehicle at the previous moment adjacent to the current moment is 9 km / s. The first vehicle speed difference is 0.5 km / s, and the second vehicle speed difference is 1 km / s. If the second vehicle speed difference remains unchanged within 300ms, it means that the second vehicle speed difference cannot be further reduced, that is, the critical integral value fails to be reduced.

[0089] It can be understood that when the first vehicle speed difference is smaller than the second vehicle speed difference, it means that the first vehicle speed difference has not decreased but increased, and when the first vehicle speed difference is greater than the synovial surface boundary threshold, it means that the first vehicle speed difference has not entered the synovial surface.

[0090] For example, the synovial surface boundary threshold may be adaptively and dynamically adjusted according to a speed difference between an actual speed of the target vehicle and a target speed.

[0091] The following combination Figure 5 The specific implementation method of determining the first vehicle speed difference and the required acceleration according to the first vehicle speed and the target vehicle speed in step S202 is described in detail.

[0092] Figure 5 Schematic diagram of the process of the vehicle speed closed-loop control method provided in the embodiment of the application Figure 4 .like Figure 5 As shown, the specific implementation of determining the first vehicle speed difference and the required acceleration according to the first vehicle speed and the target vehicle speed in the vehicle speed closed-loop control method may include the following steps:

[0093] S501: Calculate the difference between the first vehicle speed and the target vehicle speed as a first vehicle speed difference.

[0094] S502 : Based on a mapping relationship between the first error interval and the proportional-integral controller parameters, and according to the first vehicle speed difference, determine a current proportional parameter and a current integral parameter corresponding to the proportional-integral controller.

[0095] Exemplarily, the first error interval may be a vehicle speed difference interval.

[0096] Illustratively, the first error interval may be [0, 5Km / h], [5Km / h, 10Km / h], [10Km / h, 15Km / h], [15Km / h, 20Km / h], [20Km / h, 25Km / h], [25Km / h, 30Km / h], and [30Km / h, 35Km / h], etc.

[0097] For example, when the target vehicle speed is 35 km / h and the actual vehicle speed is 0 km / h, the corresponding vehicle speed difference is 35 km / h. The first error interval can be obtained by dividing the vehicle speed difference into equal parts at intervals of 5 km / h.

[0098] Exemplarily, the mapping relationship between the first error interval and the proportional-integral controller parameters may be such that two endpoint values ​​of the first error interval, ie, the speed differences between the two endpoints, are respectively set with fixed proportional parameters and integral parameters.

[0099] It should be noted that in the vehicle speed closed-loop control method provided in the embodiment of the present application, the larger the vehicle speed difference, the larger the error interval, the proportional parameter and the integral parameter should be appropriately reduced to avoid overshoot caused by excessive control output; the smaller the vehicle speed difference, the smaller the error interval, the proportional parameter and the integral parameter should be appropriately increased to speed up the convergence speed of the vehicle speed difference.

[0100] Correspondingly, in the mapping relationship between the first error interval and the proportional-integral controller parameters provided in the embodiment of the present application, the smaller the difference in vehicle speed between the two endpoints corresponding to the first error interval, the larger the corresponding proportional parameter and integral parameter; conversely, the larger the difference in vehicle speed between the two endpoints corresponding to the first error interval, the smaller the corresponding proportional parameter and integral parameter.

[0101] A possible implementation method for determining the current proportional parameter and the current integral parameter corresponding to the proportional-integral controller based on the first vehicle speed difference may be: determining the first error interval in which the vehicle speed difference is located based on the first vehicle speed difference, and linearly adjusting the proportional coefficient and the integral coefficient corresponding to the first vehicle speed difference based on the proportional parameters and the integral parameters corresponding to the two endpoint speed differences corresponding to the first error interval, so as to obtain the current proportional parameter and the current integral parameter corresponding to the PI controller.

[0102] For example, if the first speed difference is 8 km / h, the first error interval of the first speed difference is [5 km / h, 10 km / h]. Assume that the proportional parameter corresponding to the endpoint speed difference of 5 km / h in the first error interval is , the integral parameter is The proportional parameter corresponding to the endpoint speed difference of 10 km / h in the first error interval is , the integral parameter is ,in, Greater than , Greater than .

[0103] Based on the linear relationship between the first speed difference of 8 km / h, the endpoint speed difference of 5 km / h and the endpoint speed difference of 10 km / h, the proportional parameter corresponding to the endpoint speed difference of 5 km / h is , the integral parameter is , and the proportional parameter corresponding to the endpoint speed difference of 10Km / h is , the integral parameter is , linearly determine the current proportional parameter and the current integral parameter corresponding to the first vehicle speed difference.

[0104] S503 : Based on the mapping relationship between the second error interval and the proportional-integral controller parameters and according to the target vehicle speed, a compensation proportional parameter and a compensation integral parameter corresponding to the proportional-integral controller are determined.

[0105] For example, the embodiment of the present application adopts a two-stage approach, dividing the target vehicle speed into a low speed range and a high speed range. For example, when the target vehicle speed is less than or equal to 5 km / h, it is determined to be a low speed range, and when the target vehicle speed is greater than 5 km / h, it is determined to be a high speed range.

[0106] Illustratively, the second error interval may be [0, 1 km / h], [1 km / h, 2 km / h], [2 km / h, 3 km / h], [3 km / h, 4 km / h], and [4 km / h, 5 km / h], etc.

[0107] For example, when the target vehicle speed is 5 km / h and the actual vehicle speed is 0 km / h, the corresponding vehicle speed difference is 5 km / h. The second error interval can be obtained by dividing the vehicle speed difference into equal parts at intervals of 1 km / h.

[0108] It should be noted that in the vehicle speed closed-loop control method provided in the embodiment of the present application, when the target vehicle speed is in the low-speed range, the compensation proportional parameter and the compensation integral parameter are designed to improve the low-speed response speed; when the target vehicle speed is in the high-speed range, the compensation proportional parameter and the compensation integral parameter are designed to be 0, that is, the current proportional parameter and the current integral parameter are not compensated to suppress high-speed oscillations.

[0109] Based on the mapping relationship between the second error interval and the parameters of the proportional-integral controller, a possible implementation method for determining the compensation proportional parameter and compensation integral parameter corresponding to the proportional-integral controller according to the target vehicle speed can be: in response to the target vehicle speed being greater than a preset vehicle speed threshold, the compensation proportional parameter and compensation integral parameter corresponding to the proportional-integral controller are both determined to be 1; in response to the target vehicle speed being less than or equal to the preset vehicle speed threshold, the second error interval in which the speed difference lies is determined based on the speed difference between the target vehicle speed and the actual vehicle speed, and the compensation proportional coefficient and compensation integral coefficient corresponding to the speed difference are linearly adjusted based on the proportional parameters and integral parameters corresponding to the speed differences at the two endpoints of the second error interval. The specific implementation method is similar to the above and will not be repeated here.

[0110] It can be understood that in the vehicle speed closed-loop control method provided in the embodiment of the present application, a two-stage representation is adopted to distinguish the low-speed range and the high-speed range of the target vehicle speed, and when the target vehicle speed is in the low-speed range, certain compensation proportion parameters and compensation integral parameters are designed to ensure a rapid response to the low-speed target speed.

[0111] S504 , compensating the current proportional parameter using the compensation proportional parameter to obtain a target proportional parameter; and compensating the current integral parameter using the compensation integral parameter to obtain a target integral parameter.

[0112] Exemplarily, the compensation proportion parameter and the current proportion parameter are summed to obtain the target proportion parameter; and the compensation integral parameter and the current integral parameter are summed to obtain the target integral parameter.

[0113] S505 : The proportional-integral controller outputs a required acceleration based on the target proportional parameter and the target integral parameter and according to the first vehicle speed difference.

[0114] In the embodiment of the present application, the proportional parameter and the integral parameter are dynamically expressed to change in different speed difference intervals, i.e., error intervals, and smaller proportional parameters and integral parameters are calibrated in the large error interval to avoid overshoot caused by excessive control output. Appropriately large proportional parameters and integral parameters are calibrated in the small error interval to ensure stability and the adjustment speed of the small error interval, thereby accelerating the convergence speed of the actual vehicle speed to the target vehicle speed. At the same time, by using a two-stage expression to distinguish between the low-speed interval and the high-speed interval of the target vehicle speed, when the target vehicle speed is in the low-speed interval, certain compensation proportional parameters and compensation integral parameters are designed to ensure rapid response to the low-speed target speed and improve the low-speed response speed. In the high-speed interval, no compensation of the proportional parameters and integral parameters is performed to suppress high-speed oscillation.

[0115] Figure 6 This is a logic diagram of the closed-loop speed control provided by the embodiment of the present application. Figure 6As shown, the PI controller outputs a proportional value and an integral value based on a first vehicle speed difference between a target vehicle speed and an actual vehicle speed, and based on a target proportional parameter and a target integral parameter, and outputs a required acceleration based on the proportional value and the integral value.

[0116] The synovial surface comparator in the dynamic synovial controller compares the first vehicle speed difference with the product of the required acceleration and the synovial surface coefficient to determine whether the first vehicle speed difference enters the synovial surface, and locks the synovial surface boundary when the first vehicle speed difference enters the synovial surface, that is, locks the first synovial surface boundary value and the critical integral value corresponding to the proportional integral controller, and further reduces the critical integral value based on the first vehicle speed difference and the first synovial surface boundary value, and outputs the target integral value to the PI controller when the critical integral value is successfully reduced. Then the PI controller outputs the target acceleration based on the target integral value, and reduces the synovial surface by determining half of the first vehicle speed difference as the second synovial surface boundary value when the critical integral value fails to be reduced, and repeats the step of determining whether the first vehicle speed difference enters the synovial surface.

[0117] The specific implementation method in this embodiment is similar to the above and will not be repeated here.

[0118] In summary, the closed-loop speed control method provided by the embodiments of the present application has the following beneficial effects:

[0119] 1) By dynamically indicating that the proportional and integral parameters vary in different speed difference intervals, i.e., error intervals, and calibrating smaller proportional and integral parameters in large error intervals, this method avoids overshoot caused by excessive control output. Appropriately larger proportional and integral parameters are calibrated in small error intervals to ensure stability and regulation speed in small error intervals, thereby accelerating the convergence of the actual speed to the target speed.

[0120] 2) By using a two-stage representation to distinguish between low-speed and high-speed ranges of the target vehicle speed, when the target vehicle speed is in the low-speed range, specific compensation proportional parameters and compensation integral parameters are designed to ensure a rapid response to the low-speed target speed and improve the low-speed response speed. In the high-speed range, no compensation of proportional parameters and integral parameters is performed to suppress high-speed oscillation.

[0121] 3) By combining a PI controller with a dynamic sliding film controller, the critical integral value of the PI controller is constrained by the sliding film boundary value corresponding to the dynamic sliding film controller, thus avoiding excessive accumulation of the integral value in the PI controller and reducing the overshoot in the closed-loop speed control process;

[0122] 4) By calculating the first synchromesh boundary value based on the speed difference between the target speed and the actual speed and the required acceleration, and reducing the critical integral value based on the speed difference and the synchromesh boundary value, the target integral value is obtained, thereby achieving rapid convergence of the speed difference and improving the vehicle's ability to quickly respond to the target speed. At the same time, by reducing the critical integral value based on the integral reset coefficient, smooth adjustment of the integral gain in the PI controller is achieved to reduce speed oscillation in the speed closed-loop control.

[0123] The following are device embodiments of the present application, which can be used to implement the method embodiments of the present application. For details not disclosed in the device embodiments of the present application, please refer to the method embodiments of the present application.

[0124] Figure 7 This is a schematic diagram of the structure of the chassis domain control system provided in one embodiment of the present application. Figure 7 As shown, the chassis domain control system 70 provided in this embodiment includes: at least one processor 701 and a memory 702. Optionally, the chassis domain control system 70 also includes a communication component 703. The processor 701, the memory 702, and the communication component 703 are connected via a bus 704.

[0125] During the specific implementation process, at least one processor 701 executes the computer-executable instructions stored in the memory 702, so that the at least one processor 701 performs the above method.

[0126] The specific implementation process of the processor 701 can be found in the above method embodiment. Its implementation principle and technical effects are similar and will not be repeated here in this embodiment.

[0127] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the present invention may be directly executed by a hardware processor or by a combination of hardware and software modules in the processor.

[0128] The memory may include a high-speed memory (Random Access Memory, referred to as RAM), and may also include a non-volatile memory (NVM), such as at least one disk storage.

[0129] A bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. Buses can be categorized as address buses, data buses, and control buses. For ease of presentation, the buses in the drawings of this application are not limited to just one bus or just one type of bus.

[0130] An embodiment of the present application also provides a vehicle, including a vehicle speed closed-loop control system as shown in the above embodiment, or including a chassis domain control system as shown in the above embodiment.

[0131] Exemplarily, the vehicle may be an unmanned logistics vehicle.

[0132] An embodiment of the present application also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0133] An embodiment of the present application further provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the above-mentioned method is implemented.

[0134] The readable storage medium may be implemented by any type of volatile or non-volatile memory 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. The readable storage medium may be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0135] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

[0136] The division of units is merely a logical functional division; actual implementations may employ alternative divisions, such as combining or integrating multiple units or components into another system, or omitting or disabling certain features. Furthermore, any direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units, either through an interface, electrical, mechanical, or other means.

[0137] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0138] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0139] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the method of the present invention. The aforementioned storage medium includes various media that can store program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0140] Those skilled in the art will appreciate that all or part of the steps in the above-described method embodiments can be implemented using hardware associated with program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0141] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A closed-loop vehicle speed control method, characterized in that: include: Obtaining a first speed and a target speed of a target vehicle, where the first speed is the actual speed of the target vehicle at the current moment; determining a first vehicle speed difference and a required acceleration according to the first vehicle speed and the target vehicle speed; Determining a first sliding membrane face threshold value corresponding to a dynamic sliding membrane controller and a critical integral value corresponding to a proportional-integral controller according to the first vehicle speed difference and the required acceleration; reducing the critical integral value according to the first vehicle speed difference and the first synovial face threshold value to obtain a target integral value; A target acceleration is determined according to the target integral value, and the target vehicle speed closed loop is controlled according to the target acceleration.

2. The closed-loop vehicle speed control method according to claim 1, characterized in that: The determining, based on the first vehicle speed difference and the required acceleration, a first sliding membrane face threshold value corresponding to the dynamic sliding membrane controller and a critical integral value corresponding to the proportional-integral controller includes: inputting the first vehicle speed difference and the required acceleration into the dynamic sliding film controller to determine whether the first vehicle speed difference enters the sliding film surface; In response to the first vehicle speed difference entering the sliding membrane surface, the product of the required acceleration and the sliding membrane surface coefficient corresponding to the dynamic sliding membrane controller is determined to be a critical value of the first sliding membrane surface, and the integral value corresponding to the proportional-integral controller outputting the required acceleration according to the first vehicle speed difference is determined to be the critical integral value.

3. The vehicle speed closed-loop control method according to claim 1 or 2, characterized in that: The reducing the critical integral value to obtain a target integral value according to the first vehicle speed difference and the first synovial membrane facing threshold value includes: Determine the quotient of the first vehicle speed difference and the first synovial contact threshold as an integral reset coefficient, wherein the integral reset coefficient is less than 1; The critical integral value is reduced according to the integral reset coefficient to obtain the target integral value.

4. The closed-loop vehicle speed control method according to claim 3, characterized in that: The step of reducing the critical integral value according to the integral reset coefficient to obtain the target integral value includes: determining, based on the first vehicle speed difference, whether the critical integral value is successfully reduced; If the critical integral value is successfully reduced, the product of the integral reset coefficient and the critical integral value is determined as the target integral value; If the critical integral value fails to be reduced, half of the first vehicle speed difference is determined as the second synovial membrane facing threshold value, and the step of reducing the critical integral value according to the first vehicle speed difference and the second synovial membrane facing threshold value is repeated until the critical integral value is successfully reduced.

5. The closed-loop vehicle speed control method according to claim 4, characterized in that: The determining, based on the first vehicle speed difference, whether the critical integral value is successfully reduced includes: determining whether the first vehicle speed difference is less than or equal to 0; If the first vehicle speed difference is less than or equal to 0, it is determined that the critical integral value is successfully reduced; If the first speed difference is equal to the second speed difference, and the second speed difference remains unchanged within a preset time period, or if the first speed difference is less than the second speed difference, and the first speed difference is greater than the synovial face critical threshold, it is determined that the critical integral value has failed to be reduced, and the second speed difference is the difference between the second speed and the target speed, and the second speed is the actual speed corresponding to the target vehicle at the previous moment adjacent to the current moment.

6. The vehicle speed closed-loop control method according to claim 1 or 2, characterized in that: The determining a first vehicle speed difference and a required acceleration according to the first vehicle speed and the target vehicle speed includes: calculating a difference between the first vehicle speed and the target vehicle speed as the first vehicle speed difference; determining, based on a mapping relationship between a first error interval and parameters of a proportional-integral controller and according to the first vehicle speed difference, a current proportional parameter and a current integral parameter corresponding to the proportional-integral controller; determining a compensation proportional parameter and a compensation integral parameter corresponding to the proportional integral controller according to the target vehicle speed based on a mapping relationship between the second error interval and the proportional integral controller parameters; The current proportional parameter is compensated by using the compensation proportional parameter to obtain a target proportional parameter; the current integral parameter is compensated by using the compensation integral parameter to obtain a target integral parameter; The proportional-integral controller outputs the required acceleration according to the first vehicle speed difference based on the target proportional parameter and the target integral parameter.

7. A closed-loop vehicle speed control system, characterized in that: include: Self-driving control system and chassis domain control system; The self-driving control system is used to send a target vehicle speed planning instruction to the chassis domain control system; The chassis domain control system is used to respond to the target vehicle speed planning instruction and execute the vehicle speed closed-loop control method according to any one of claims 1 to 6.

8. A chassis domain control system, characterized in that: include: a processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the vehicle speed closed-loop control method according to any one of claims 1 to 6.

9. A vehicle, characterized in that: Including the vehicle speed closed-loop control system as described in claim 7, or including the chassis domain control system as described in claim 8.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which are used to implement the vehicle speed closed-loop control method according to any one of claims 1 to 6 when executed by a processor.

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