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

Abstract

This application provides a vehicle speed closed-loop control method, system, vehicle, and storage medium, relating to the field of autonomous driving technology. The method combines a PI controller and a dynamic sliding diaphragm controller. The critical integral value of the PI controller is constrained by the first sliding diaphragm surface boundary value corresponding to the dynamic sliding diaphragm controller, preventing excessive accumulation of integral values ​​in the PI controller and reducing overshoot during the vehicle speed closed-loop control process. Simultaneously, the first sliding diaphragm surface boundary value is calculated based on the first vehicle speed difference and the required acceleration. Based on the first vehicle speed difference and the first sliding diaphragm surface boundary value, the critical integral value is reduced to obtain the target integral value, achieving rapid convergence to the first vehicle speed difference and improving the vehicle's performance in quickly responding to the target speed.

Description

Technical Field

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

[0002] Currently, in the autonomous logistics vehicle industry, the control system of autonomous logistics vehicles typically adopts a hierarchical structure, with the Autonomous Control Unit (ACU) and the Chassis Domain Control Unit (CDCU) working together. The ACU is responsible for planning the vehicle's driving path and target speed, while the CDCU is responsible for executing the planning commands sent by the ACU, including the driving path and target speed.

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

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

[0005] This 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 vehicle speed using a PI controller in related technologies.

[0006] In a first aspect, this application provides a vehicle speed closed-loop control method, comprising: acquiring 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 sliding surface threshold value corresponding to a dynamic sliding 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 sliding surface threshold value to obtain a target integral value; determining a target acceleration based on the target integral value, and controlling the target vehicle speed in a closed loop based on the target acceleration.

[0007] In one possible implementation, the critical integral value of the first sliding surface corresponding to the dynamic sliding surface controller and the critical integral value of the PI controller are determined based on the first vehicle speed difference and the demand acceleration. This includes: inputting the first vehicle speed difference and the demand acceleration into the dynamic sliding surface controller to determine whether the first vehicle speed difference enters the sliding surface; responding to the first vehicle speed difference entering the sliding surface, determining that the product of the demand acceleration and the sliding surface coefficient corresponding to the dynamic sliding surface controller is the critical integral value of the first sliding surface, and determining that the integral value corresponding to the PI controller outputting the demand acceleration according to the first vehicle speed difference is the critical integral value.

[0008] In one possible implementation, the target integral value is obtained by reducing the critical integral value based on the first vehicle speed difference and the first slip surface boundary value, including: determining the quotient of the first vehicle speed difference and the first slip surface boundary value as the integral reset coefficient, wherein the integral reset coefficient is less than 1; and the target integral value is obtained by reducing the critical integral value based on the integral reset coefficient.

[0009] In one possible implementation, the critical integral value is reduced to obtain the target integral value based on the integral reset coefficient, including: determining whether the critical integral value has been successfully reduced based on the first vehicle speed difference; if the critical integral value has been 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 has failed to be reduced, half of the first vehicle speed difference is determined as the second slip surface boundary value, and the steps of reducing the critical integral value based on the first vehicle speed difference and the second slip surface boundary value are repeated until the critical integral value is successfully reduced.

[0010] In one possible implementation, determining whether the critical integral value has been successfully reduced based on the first vehicle speed difference 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, determining that the critical integral value has been 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 period, 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 sliding surface boundary 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 time adjacent to the current time.

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

[0012] Secondly, this 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 command to the chassis domain control system; the chassis domain control system is used to respond to the target vehicle speed planning command and execute the vehicle speed closed-loop control method provided in the first aspect above.

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

[0014] Fourthly, this application provides a vehicle including a vehicle speed closed-loop control system as provided in the second aspect above, or a chassis domain control system as provided in the third aspect above.

[0015] Fifthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the vehicle speed closed-loop control method provided in the first aspect above.

[0016] In a sixth aspect, this application provides a computer program product, comprising: a computer program that, 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 acquire the actual vehicle speed (i.e., the first vehicle speed) and the target vehicle speed at the current moment. Based on the first and target vehicle speeds, a first speed difference and a required acceleration are determined. Further, based on the first speed difference and the required acceleration, a first sliding face boundary value corresponding to the dynamic sliding controller and a critical integral value corresponding to the PI controller are determined. Then, based on the first speed difference and the first sliding face boundary 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 control is performed based on the target acceleration. This application employs a combination of a PI controller and a dynamic sliding controller. The first sliding face boundary value corresponding to the dynamic sliding controller constrains the critical integral value corresponding to the PI controller, preventing excessive accumulation of integral values ​​in the PI controller and reducing overshoot during the vehicle speed closed-loop control process. Meanwhile, by calculating the critical value of the first slicker face based on the first speed difference and the required acceleration, and by reducing the critical integral value based on the first speed difference and the first slicker face, the target integral value is obtained, thereby achieving rapid convergence of the first speed difference and improving the vehicle's performance in responding quickly to the target speed. Attached Figure Description

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

[0019] Figure 1 This is a schematic diagram of the structure of the vehicle speed closed-loop control system provided in the embodiments of this application;

[0020] Figure 2 A flowchart illustrating the vehicle speed closed-loop control method provided in this application embodiment. Figure 1 ;

[0021] Figure 3 A flowchart illustrating the vehicle speed closed-loop control method provided in this application embodiment. Figure 2 ;

[0022] Figure 4 A flowchart illustrating the vehicle speed closed-loop control method provided in this application embodiment. Figure 3 ;

[0023] Figure 5 A flowchart illustrating the vehicle speed closed-loop control method provided in this application embodiment. Figure 4 ;

[0024] Figure 6 A schematic diagram of the closed-loop speed control provided in the embodiments of this application;

[0025] Figure 7 This is a schematic diagram of the chassis domain control system provided in one embodiment of this application.

[0026] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0028] In related technologies, the ACU sends a target vehicle speed command to the CDCU. Based on vehicle dynamics, the CDCU adjusts the motor torque to achieve closed-loop control of the target vehicle speed. Typically, the CDCU uses a proportional-integral (PI) controller to calculate the required acceleration based on the deviation between the target speed and the actual vehicle speed, and then uses this required acceleration to achieve closed-loop control of the target vehicle speed. However, when using a PI controller for vehicle speed closed-loop control, to ensure good vehicle response performance, the proportional (Kp) or integral (Ki) parameters of the PI controller need to be increased. However, excessively large proportional or integral parameters can lead to problems such as large overshoot and slow recovery due to factors like vehicle weight and inertia.

[0029] To address the problems existing in related technologies, this application adopts a combination of a PI controller and a dynamic sliding diaphragm controller. The critical integral value of the PI controller is constrained by the sliding diaphragm surface boundary value of the dynamic sliding diaphragm controller, preventing excessive accumulation of the integral value in the PI controller and reducing overshoot in the vehicle speed closed-loop control process. Simultaneously, by using the speed difference between the actual vehicle speed and the target vehicle speed and the first sliding diaphragm surface boundary value of the required acceleration, and based on the speed difference and the sliding diaphragm surface boundary value, the critical integral value is reduced to obtain the target integral value. This achieves rapid convergence of the speed difference and improves the vehicle's performance in quickly responding to the target speed.

[0030] The following is a combination of... Figure 1 The vehicle speed closed-loop control system provided in the embodiments of this application will be described in detail.

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

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

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

[0034] The target vehicle speed is included in the target speed planning command sent by the autonomous driving control system to the chassis domain control system.

[0035] For example, the autonomous driving control system and the chassis domain control system can communicate with each other via a communication bus.

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

[0037] The following is based on Figure 1 The chassis domain control system shown is the execution subject. The specific implementation of the vehicle speed closed-loop control method provided in this application embodiment will be described in detail with reference to specific embodiments.

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

[0039] S201, obtain the first speed and target speed of the target vehicle.

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

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

[0042] For example, the first speed of the target vehicle can be obtained based on wheel speed sensors, Global Positioning System (GPS) and Inertial Measurement Unit (IMU). This application embodiment does not specifically limit the method of obtaining the first speed, but can be determined according to the actual application requirements.

[0043] For example, the target vehicle speed can be as described above. Figure 1The autonomous driving control system shown dynamically calculates based on factors such as route planning, traffic conditions, road conditions, and traffic regulations, and then sends the results to the chassis domain control system.

[0044] S202, determine the first speed difference and the required acceleration based on 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 defined as the first vehicle speed difference, and this first vehicle speed difference is input into a PI controller to obtain the 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, based on the first vehicle speed difference and the required acceleration, determine the first sliding surface critical value of the dynamic sliding surface controller and the critical integral value of the PI controller.

[0047] For example, the critical value of the first slip surface can be the critical value corresponding to the first vehicle speed difference entering the slip surface.

[0048] For example, the first synovial surface boundary value is determined based on the demand acceleration and the synovial surface coefficient.

[0049] In one possible implementation, when the first speed difference enters the slip surface, the product of the slip surface coefficient and the required acceleration can be determined as the first slip surface boundary value.

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

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

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

[0053] S204. Based on the first vehicle speed difference and the first slip surface boundary value, the critical integral value is reduced to obtain the target integral value.

[0054] In one possible implementation, the integral reset coefficient can be determined based on the first vehicle speed difference and the first slip surface threshold value, and the critical integral value can be reduced based on the integral reset coefficient to obtain the target integral value.

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

[0056] S205 determines the target acceleration based on the target integral value, and controls the target vehicle speed in a closed loop based on the target acceleration.

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

[0058] For example, before adjusting the motor's current and voltage to achieve the output of the motor's drive torque, the motor drive torque calculated by the vehicle dynamics model can be filtered to achieve smoothing of the motor drive torque.

[0059] For example, the filter can be a low-pass filter.

[0060] In this embodiment, the actual speed of the target vehicle at the current moment (i.e., the first speed) and the target speed are obtained. Based on the first speed and the target speed, a first speed difference and a required acceleration are determined. Further, based on the first speed difference and the required acceleration, a first sliding surface boundary value corresponding to the dynamic sliding controller and a critical integral value corresponding to the PI controller are determined. Then, based on the first speed difference and the first sliding surface boundary 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 speed closed-loop control is performed based on the target acceleration. This embodiment uses a combination of a PI controller and a dynamic sliding controller. The first sliding surface boundary value corresponding to the dynamic sliding controller constrains the critical integral value corresponding to the PI controller, preventing excessive accumulation of integral values ​​in the PI controller and reducing overshoot in the speed closed-loop control process. Simultaneously, by calculating the first sliding surface boundary value 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 sliding surface boundary value to obtain the target integral value, rapid convergence of the first speed difference is achieved, improving the vehicle's performance in quickly responding to the target speed.

[0061] The following is combined with Figure 3 The specific implementation method of determining the first sliding surface critical value of the dynamic sliding controller and the critical integral value of the proportional-integral controller based on the first vehicle speed difference and the required acceleration in step S203 is explained in detail.

[0062] Figure 3 A flowchart illustrating the vehicle speed closed-loop control method provided in this application embodiment. Figure 2 .like Figure 3 As shown, the specific implementation method of determining the first sliding face critical value of the dynamic sliding diaphragm controller and the critical integral value of the proportional-integral controller based on the first vehicle speed difference and the required acceleration in this vehicle speed closed-loop control method may include the following steps:

[0063] S301, input the first vehicle speed difference and the required acceleration into the dynamic sliding membrane controller to determine whether the first vehicle speed difference enters the sliding membrane surface.

[0064] For example, a slid surface comparator is designed into a dynamic slid controller.

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

[0066] For example, when the first speed difference is less than the product of the required acceleration and the slip surface coefficient, it is determined that the first speed difference has entered the slip surface; when the first speed difference is greater than or equal to the product of the required acceleration and the slip surface coefficient, it is determined that the first speed difference has not entered the slip surface.

[0067] In one possible implementation, when it is determined that the first vehicle speed difference has entered the sliding surface, step S302 is executed; when it is determined that the first vehicle speed difference has not entered the sliding surface, the proportional and integral parameters in the PI controller are dynamically adjusted based on the first vehicle speed difference and the target vehicle speed, thereby adjusting the demand acceleration output by the PI controller. The adjusted demand acceleration and the first vehicle speed difference are then compared with the sliding surface. The sliding surface comparator compares the first vehicle speed difference with the product of the adjusted demand acceleration and the sliding surface coefficient again. This process is repeated 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 demand acceleration and the sliding surface coefficient.

[0068] S302, in response to the first vehicle speed difference entering the slip surface, determine that the product of the required acceleration and the slip surface coefficient corresponding to the dynamic slip surface controller is the critical value of the first slip surface, and determine 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 one possible implementation, in response to the first vehicle speed difference entering the slid surface, the first slid surface boundary value and critical integral value are locked.

[0070] In this embodiment, by inputting the first vehicle speed difference and the required acceleration into the dynamic slip surface controller, it is determined whether the first vehicle speed difference enters the slip surface. When responding to the first vehicle speed difference entering the slip surface, the product of the required acceleration and the slip surface coefficient corresponding to the dynamic slip surface controller is determined to be the critical value of the first slip surface. The integral value corresponding to the output of the required acceleration by the proportional-integral controller based on 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 and causing overshoot, thereby enabling the first vehicle speed of the target vehicle to converge quickly near the target vehicle speed and improving the vehicle's performance in responding quickly to the target vehicle speed.

[0071] The following is combined with Figure 4 The specific implementation method of reducing the critical integral value and obtaining the target integral value based on the first vehicle speed difference and the first slip surface boundary value in step S204 is explained in detail.

[0072] Figure 4 A flowchart illustrating the vehicle speed closed-loop control method provided in this application embodiment. Figure 3 .like Figure 4 As shown, the specific implementation method of reducing the critical integral value and obtaining the target integral value based on the first vehicle speed difference and the first sliding diaphragm surface boundary value in this vehicle speed closed-loop control method may include the following steps:

[0073] S401, the quotient of the first vehicle speed difference and the first slurry surface boundary value is determined as the integral reset coefficient, which is less than 1.

[0074] For example, the integral reset factor is used to reduce the critical integral value.

[0075] For example, the integral reset factor is used to update the integral portion in the PI controller.

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

[0077] S402, based on the integral reset coefficient, reduce the critical integral value to obtain the target integral value.

[0078] Optionally, one possible implementation is as follows: determine whether the critical integral value has been successfully reduced based on the first vehicle speed difference; if the critical integral value has been successfully reduced, then the product of the integral reset coefficient and the critical integral value is determined as the target integral value; if the critical integral value has failed to be reduced, then half of the first vehicle speed difference is determined as the second slip surface boundary value, and the steps of reducing the critical integral value based on the first vehicle speed difference and the second slip surface boundary value are repeated until the critical integral value is successfully reduced.

[0079] For example, when the critical integral value fails to shrink, half of the first vehicle speed difference is determined as the critical value of the second slid surface, thereby reducing the slid surface.

[0080] For example, when the critical integral value fails to decrease, half of the first vehicle speed difference is determined as the second slip surface boundary value, and the product between 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 vehicle speed difference and the reset integral value, and further obtains the current actual vehicle speed of the target vehicle based on the reset acceleration. The actual vehicle speed is less than the target vehicle speed. The current vehicle speed difference is calculated using the actual vehicle speed and the target vehicle speed. The current vehicle speed difference is input into the slip surface comparator to determine whether the current vehicle speed difference is less than the second slip surface boundary value. When the current vehicle speed difference is less than the second slip surface boundary value, the reset integral value is reduced according to the current vehicle speed difference and the second slip surface boundary value until the reset integral value is successfully reduced.

[0081] In this embodiment, the quotient of the first vehicle speed difference and the critical value of the first sliding diaphragm surface is determined as the integral reset coefficient. Based on the integral reset coefficient, the critical integral value is reduced to obtain the target integral value. This embodiment achieves smooth adjustment of the integral gain in the PI controller by reducing the critical integral value based on the integral reset coefficient, thereby reducing vehicle speed oscillations in the vehicle speed closed-loop control.

[0082] Optionally, one possible implementation of determining whether the critical integral value has been successfully reduced based on the first vehicle speed difference is as follows: determine 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, determine that the critical integral value has been 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 period, 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 sliding surface boundary threshold, then determine 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 time adjacent to the current time.

[0083] It should be noted that the specific size of the synovial surface boundary threshold is not limited in the embodiments of this application; it can be determined according to the 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 this application embodiment, 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] For example, the preset duration can be 300ms.

[0087] It is understandable that when the first speed difference equals the second speed difference, and the second speed difference remains unchanged within a preset time period, it means that after the speed difference between the actual speed of the target vehicle and the target speed is reduced to the middle position between 0 and the current speed difference, it cannot be reduced further and remains at the current position.

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

[0089] It is understandable that when the first speed difference is less than the second speed difference, it means that the first speed difference has not decreased but has increased. And when the first speed difference is greater than the slip surface boundary threshold, it means that the first speed difference has not entered the slip surface.

[0090] For example, the synovial surface boundary threshold can be adaptively and dynamically adjusted based on the speed difference between the actual speed of the target vehicle and the target speed.

[0091] The following is combined with Figure 5 The specific implementation method of determining the first speed difference and the required acceleration based on the first vehicle speed and the target vehicle speed in step S202 is explained in detail.

[0092] Figure 5 A flowchart illustrating the vehicle speed closed-loop control method provided in this application embodiment. Figure 4 .like Figure 5 As shown, the specific implementation method for determining the first speed difference and the required acceleration based on the first vehicle speed and the target vehicle speed in this closed-loop speed control method may include the following steps:

[0093] S501, calculate the difference between the first vehicle speed and the target vehicle speed as the first vehicle speed difference.

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

[0095] For example, the first error range can be the vehicle speed difference range.

[0096] For example, the first error range can be [0, 5 km / h], [5 km / h, 10 km / h], [10 km / h, 15 km / h], [15 km / h, 20 km / h], [20 km / h, 25 km / h], [25 km / h, 30 km / h], and [30 km / h, 35 km / 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 speed difference is 35 km / h. Dividing this speed difference into equal intervals of 5 km / h, the first error range mentioned above can be obtained.

[0098] For example, the mapping relationship between the first error interval and the proportional-integral controller parameters can be that the two endpoint values ​​of the first error interval, i.e., the speed difference 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 this application embodiment, the larger the vehicle speed difference, i.e. the larger the error range, the more appropriate the proportional and integral parameters should be to avoid excessive control output leading to overshoot; the smaller the vehicle speed difference, i.e. the smaller the error range, the more appropriate the proportional and integral parameters should be to accelerate the convergence speed of the vehicle speed difference.

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

[0101] One possible way to determine the current proportional and integral parameters of the proportional-integral controller based on the first vehicle speed difference is as follows: determine the first error interval in which the vehicle speed difference is located based on the first vehicle speed difference, and linearly adjust the proportional and integral coefficients corresponding to the first vehicle speed difference based on the proportional and integral parameters corresponding to the two endpoints of the first error interval, so as to obtain the current proportional and integral parameters of the PI controller.

[0102] For example, if the first speed difference is 8 km / h, then the first error interval where the first speed difference lies is [5 km / h, 10 km / h]. Assume the proportional parameter corresponding to the midpoint speed difference of 5 km / h in this first error interval is... The integral parameter is The proportional parameter corresponding to the speed difference of 10 km / h at the midpoint of 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 speed difference at the end of the first error interval of 5 km / h, and the speed difference at the end of the first error interval of 10 km / h, the proportional parameter corresponding to the speed difference at the end of the first error interval of 5 km / h is... The integral parameter is And the proportional parameter corresponding to a speed difference of 10 km / h at the endpoints is The integral parameter is The current proportional parameter and the current integral parameter corresponding to the first speed difference are linearly determined.

[0104] S503, based on the mapping relationship between the second error interval and the proportional-integral controller parameters, determines the corresponding proportional compensation parameters and integral compensation parameters of the proportional-integral controller according to the target vehicle speed.

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

[0106] For example, the second error range can 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 speed difference is 5 km / h. Dividing this speed difference into equal intervals of 1 km / h, the second error interval mentioned above can be obtained.

[0108] It should be noted that in the vehicle speed closed-loop control method provided in this application embodiment, the target vehicle speed is in the low-speed range, and compensation proportional parameters and compensation integral parameters are designed to improve the low-speed response speed; when the target vehicle speed is in the high-speed range, the compensation proportional parameters and compensation integral parameters are both 0, that is, no compensation is made for the current proportional parameters and the current integral parameters, so as to suppress high-speed oscillation.

[0109] Based on the mapping relationship between the second error interval and the proportional-integral (PI) controller parameters, one possible implementation for determining the proportional compensation parameter and integral compensation parameter of the PI controller according to the target vehicle speed is as follows: When the target vehicle speed is greater than a preset speed threshold, determine that both the proportional compensation parameter and the integral compensation parameter of the PI controller are 1; when the target vehicle speed is less than or equal to the preset speed threshold, determine the second error interval containing the speed difference between the target speed and the actual speed, and linearly adjust the proportional compensation coefficient and the integral compensation coefficient corresponding to the speed difference based on the proportional and integral parameters corresponding to the two endpoints of the second error interval. The specific implementation is similar to the above and will not be elaborated further here.

[0110] It is understood that in the vehicle speed closed-loop control method provided in this application embodiment, a two-segment representation is used to distinguish the low-speed range and high-speed range of the target vehicle speed. When the target vehicle speed is in the low-speed range, certain compensation proportional parameters and compensation integral parameters are designed to ensure rapid response to the low-speed target speed.

[0111] S504, the current proportional parameter is compensated using the compensation proportional parameter to obtain the target proportional parameter; the current integral parameter is compensated using the compensation integral parameter to obtain the target integral parameter.

[0112] For example, the target proportional parameter is obtained by summing the compensation proportional parameter and the current proportional parameter; the target integral parameter is obtained by summing the compensation integral parameter and the current integral parameter.

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

[0114] In this embodiment, the values ​​of proportional and integral parameters change dynamically across different speed difference ranges (error ranges). Smaller proportional and integral parameters are calibrated within the large error range to avoid overshoot due to excessive control output. Appropriately larger proportional and integral parameters are calibrated within the small error range to ensure stability and adjustment speed, thus accelerating the convergence of the actual vehicle speed to the target speed. Simultaneously, a two-segment representation distinguishes between the low-speed and high-speed ranges of the target vehicle speed. When the target speed is in the low-speed range, certain compensation proportional and integral parameters are designed to ensure rapid response to the low-speed target speed and improve low-speed response. No compensation for proportional and integral parameters is performed in the high-speed range to suppress high-speed oscillations.

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

[0116] The slip surface comparator in the dynamic slip surface controller compares the first vehicle speed difference with the product of the required acceleration and the slip surface coefficient to determine whether the first vehicle speed difference enters the slip surface. When the first vehicle speed difference enters the slip surface, the slip surface boundary is locked, that is, the first slip surface boundary value and the critical integral value corresponding to the proportional-integral controller are locked. Based on the first vehicle speed difference and the first slip surface boundary value, the critical integral value is reduced. When the critical integral value is successfully reduced, the target integral value is output to the PI controller. Then, the PI controller outputs the target acceleration based on the target integral value. When the critical integral value fails to be reduced, the slip surface is reduced by determining half of the first vehicle speed difference as the second slip surface boundary value, and the steps of determining whether the first vehicle speed difference enters the slip surface are repeated.

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

[0118] In summary, the vehicle speed closed-loop control method provided in this application has the following beneficial effects:

[0119] 1) By dynamically representing the changes in the values ​​of proportional and integral parameters in different speed difference ranges, i.e. error ranges, smaller proportional and integral parameters are calibrated in the large error range to avoid overshoot caused by excessive control output, and appropriately larger proportional and integral parameters are calibrated in the small error range to ensure stability and adjustment speed in the small error range, thereby accelerating the convergence speed of the actual vehicle speed to the target vehicle speed.

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

[0121] 3) By combining a PI controller and a dynamic sliding diaphragm controller, the critical integral value of the PI controller is constrained by the critical value of the sliding diaphragm surface corresponding to the dynamic sliding diaphragm controller, so as to avoid excessive accumulation of integral value in the PI controller and reduce overshoot in the vehicle speed closed-loop control process.

[0122] 4) The critical integral value of the first sliding diaphragm is calculated based on the speed difference between the target speed and the actual speed and the required acceleration. Based on the speed difference and the critical integral value of the sliding diaphragm, the critical integral value is reduced to obtain the target integral value, thereby achieving rapid convergence of the speed difference and improving the vehicle's performance in responding quickly to the target speed. At the same time, by reducing the critical integral value based on the integral reset coefficient, the integral gain in the PI controller is smoothly adjusted to reduce speed oscillation in the closed-loop speed control.

[0123] The following are embodiments of the apparatus described in this application, which can be used to execute the embodiments of the method described in this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the method described in this application.

[0124] Figure 7 This is a schematic diagram of the chassis domain control system provided in one embodiment of this 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 further includes a communication component 703. The processor 701, memory 702, and communication component 703 are connected via a bus 704.

[0125] In a specific implementation, at least one processor 701 executes computer execution instructions stored in memory 702, causing at least one processor 701 to perform the above-described method.

[0126] The specific implementation process of processor 701 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0127] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0128] The memory may include random access memory (RAM) and non-volatile memory (NVM), such as at least one disk storage device.

[0129] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

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

[0131] For example, the vehicle could be an unmanned logistics vehicle.

[0132] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0133] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0134] The aforementioned readable storage medium 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. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0135] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0136] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0137] The units described as separate components may or may not be physically separate. The 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 the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0138] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can 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 this invention, or the part that contributes to the prior art, or a part 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 to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0140] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to 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; and 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 other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A closed-loop speed control method, characterized in that, include: Obtain the first speed and the target speed of the target vehicle, wherein the first speed is the actual speed of the target vehicle at the current moment; Based on the first vehicle speed and the target vehicle speed, determine the first speed difference and the required acceleration; Based on the first vehicle speed difference and the required acceleration, determine the first sliding surface critical value of the dynamic sliding surface controller and the critical integral value of the proportional-integral controller. Based on the first vehicle speed difference and the first slip surface boundary value, the critical integral value is reduced to obtain the target integral value; Based on the target integral value, the target acceleration is determined, and based on the target acceleration, the target vehicle speed is controlled in a closed loop.

2. The vehicle speed closed-loop control method according to claim 1, characterized in that, The step of determining the first slip surface critical value corresponding to the dynamic slip surface controller and the critical integral value corresponding to the proportional-integral controller based on the first vehicle speed difference and the required acceleration includes: The first vehicle speed difference and the required acceleration are input into the dynamic slip film controller to determine whether the first vehicle speed difference enters the slip film surface; In response to the first vehicle speed difference entering the slip surface, the product of the required acceleration and the slip surface coefficient corresponding to the dynamic slip surface controller is determined to be the critical value of the first slip 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 step of reducing the critical integral value based on the first vehicle speed difference and the first slip surface boundary value to obtain the target integral value includes: The quotient of the first vehicle speed difference and the first sliding diaphragm surface boundary value is determined as the integral reset coefficient, and the integral reset coefficient is less than 1. The target integral value is obtained by reducing the critical integral value based on the integral reset coefficient.

4. The vehicle speed closed-loop 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: Based on the first vehicle speed difference, determine whether the critical integral value has been 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 reduction of the critical integral value fails, half of the first vehicle speed difference is determined as the second slip surface boundary value, and the steps of reducing the critical integral value based on the first vehicle speed difference and the second slip surface boundary value are repeated until the critical integral value is successfully reduced.

5. The vehicle speed closed-loop control method according to claim 4, characterized in that, The step of determining whether the critical integral value has been successfully reduced based on the first vehicle speed difference includes: Determine 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 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 period, or if the first speed difference is less than the second speed difference, and the first speed difference is greater than the sliding surface boundary threshold, then it is determined that the reduction of the critical integral value has failed. The second speed difference is the difference between the second speed and the target speed, and the second speed is the actual speed of the target vehicle at the previous time adjacent to the current time.

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

7. A vehicle speed closed-loop control system, characterized in that, include: Autonomous driving control system and chassis domain control system; The autonomous driving control system is used to send target speed planning instructions to the chassis domain control system; The chassis domain control system is used to respond to the target vehicle speed planning command and execute the vehicle speed closed-loop control method as described in 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-executed instructions; The processor executes computer execution instructions stored in the memory to implement the vehicle speed closed-loop control method as described in any one of claims 1 to 6.

9. A vehicle, characterized in that, It includes the vehicle speed closed-loop control system as described in claim 7, or 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, when executed by a processor, are used to implement the vehicle speed closed-loop control method as described in any one of claims 1 to 6.

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