Semitrailer truck reverse control method, controller and system, and semitrailer truck

Abstract

The application provides a semi-trailer train reverse control method, a controller, a system and a semi-trailer, and solves the problem that it is difficult to realize high precision and track a predetermined trajectory to realize reverse parking in the prior art. The semi-trailer train reverse control method is based on a reverse reference trajectory and a trailer pose to calculate a desired front wheel steering angle of a tractor, can control a tractor-trailer included angle to be consistent with a desired tractor-trailer included angle, and realize path tracking during reverse parking. Meanwhile, the desired throttle opening and / or desired brake pressure are determined according to the speed of the tractor and the reference speed of the tractor, so that the actual speed of the tractor during reverse parking can be controlled to be consistent with the reference speed, speed tracking is realized, the speed and the path are cooperated to realize tracking of the reverse reference trajectory, the tracking precision of the reference trajectory during reverse parking is improved, and the reverse stability of the semi-trailer train is improved.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, specifically to a method and controller for reversing semi-trailer truck trains, a system, and a semi-trailer truck. Background Technology

[0002] With the continuous maturation of artificial intelligence and autonomous driving technologies, the application scope of autonomous driving in commercial vehicles is constantly expanding in scenarios such as trunk logistics, ports, mines, and industrial parks. Semi-trailer trucks have become the mainstay of logistics cargo transportation due to their large load capacity, high transportation efficiency, low cost, and good fuel economy; in enclosed port scenarios, semi-trailer container trucks are the preferred choice. In port and industrial park applications, semi-trailer trucks need to automatically track reference paths with high precision at low speeds to achieve accurate reversing into parking positions.

[0003] A semi-trailer truck train system consists of a tractor unit and a trailer, connected by a traction saddle and a drawbar. While the dynamics of a semi-trailer truck train are open-loop stable when moving forward, the kinematic model remains nonlinear, unstable, and uncertain during reversing, even at low speeds. The kinematics and dynamics during reversing are open-loop unstable, making collisions and folding more likely, thus hindering high-precision reversing into parking positions while tracking a predetermined trajectory. Summary of the Invention

[0004] In view of this, this application provides a semi-trailer truck reversing control method, controller, system, and semi-trailer truck, which solves the problem in the prior art that semi-trailer trucks are difficult to reverse into position with high precision and by tracking a predetermined trajectory.

[0005] As a first aspect of this application, this application provides a method for reversing a semi-trailer truck train, comprising: constructing a tractor-trailer kinematic model of the semi-trailer truck train, wherein the tractor-semi-trailer kinematic model includes at least the geometric parameters of the semi-trailer truck train; acquiring the current trailer position and the trailer's reversing reference trajectory; calculating the desired front wheel angle of the tractor based on the trailer's reversing reference trajectory, the current trailer position, the current angle between the tractor and trailer, and the tractor-trailer kinematic model, so as to control the front wheels of the tractor to rotate at the desired front wheel angle; determining the reference speed of the tractor based on the trailer's reversing reference trajectory; acquiring the current speed of the tractor, and determining a desired throttle opening and / or a desired braking pressure based on the current speed of the tractor and the reference speed of the tractor, so as to control the throttle system of the semi-trailer to operate at the desired throttle opening and the braking system to operate at the desired braking pressure.

[0006] The reversing control method for semi-trailer trucks disclosed in this application calculates the desired front wheel angle of the tractor unit based on a reversing reference trajectory and the trailer's position, thereby controlling the front wheels of the tractor unit to rotate at the desired front wheel angle. This ensures that the tractor-trailer angle matches the desired tractor-trailer angle, achieving path tracking during reversing. Simultaneously, the method determines the desired throttle opening and / or desired braking pressure based on the tractor unit's speed and reference speed, controlling the semi-trailer's throttle system to operate at the desired throttle opening and the braking system to operate at the desired braking pressure. The braking pressure is applied to control the actual speed of the tractor unit during reversing to maintain consistency with the reference speed, thereby achieving speed tracking. In other words, the semi-trailer truck reversing control method provided in this application is based on a reversing reference trajectory, using both speed and path as two working forces to track the reversing reference trajectory. This improves the accuracy of tracking the reference trajectory during reversing, thus enhancing the reversing stability of the semi-trailer truck. Furthermore, when the semi-trailer truck operates in application scenarios requiring different reversing speeds, it can achieve precise reversing into position based on the reversing reference trajectory.

[0007] In one embodiment of this application, calculating the desired front wheel angle of the tractor based on the reversing reference trajectory of the trailer, the current trailer position, the current angle between the tractor and trailer, and the tractor-trailer kinematic model includes: calculating the desired angle between the tractor and trailer corresponding to the semi-trailer train based on the reversing reference trajectory and the current trailer position; and calculating the desired front wheel angle of the tractor based on the tractor-trailer kinematic model, according to the current angle between the tractor and trailer and the desired angle between the tractor and trailer.

[0008] In one embodiment of this application, the step of calculating the expected angle between the tractor and trailer corresponding to the semi-trailer train based on the reversing reference trajectory and the current trailer position includes: obtaining the longitudinal distance between the rear axle center of the tractor and the tractor-trailer articulation point, and the longitudinal distance between the tractor-trailer articulation point and the rear axle center of the trailer; calculating the normal distance between the rear axle center of the trailer and the projection point, and the difference between the heading angle of the trailer and the heading angle of the projection point, based on the reversing reference trajectory and the current trailer position, wherein the projection point is the trajectory point on the reversing reference trajectory with the shortest straight-line distance to the rear axle center of the trailer; and calculating the expected angle between the tractor and trailer corresponding to the semi-trailer train based on the normal distance between the rear axle center of the trailer and the projection point, the difference between the heading angle of the trailer and the heading angle of the projection point, the curvature of the projection point, the longitudinal distance between the rear axle center of the tractor and the tractor-trailer articulation point, and the longitudinal distance between the tractor-trailer articulation point and the rear axle center of the trailer. The desired tractor-trailer angle can be calculated by calculating the lateral and heading errors and then using these errors as a basis.

[0009] In one embodiment of this application, after calculating the expected angle between the tractor and trailer corresponding to the semi-trailer train based on the normal distance between the center of the trailer's rear axle and the projection point, the difference between the trailer's heading angle and the projection point's heading angle, the curvature of the projection point, the longitudinal distance between the center of the tractor's rear axle and the tractor-trailer articulation point, and the longitudinal distance between the tractor-trailer articulation point and the center of the trailer's rear axle, the step of calculating the expected angle between the tractor and trailer corresponding to the semi-trailer train based on the reversing reference trajectory and the current trailer pose further includes: determining the curvature of the reversing reference trajectory based on the trailer's reversing reference trajectory; Based on the curvature of the reversing reference trajectory, the desired angle between the tractor and trailer is compensated to determine the compensated desired angle between the tractor and trailer. Specifically, calculating the desired front wheel angle of the tractor based on the tractor-trailer kinematic model, according to the current angle and the desired angle of the tractor-trailer, includes: obtaining the compensated desired angle of the tractor-trailer, and calculating the desired front wheel angle of the tractor based on the tractor-trailer kinematic model, according to the current angle and the compensated desired angle of the tractor-trailer. The calculation of the desired angle between the tractor and trailer... At the same time, the desired tractor-trailer angle is compensated based on the system feedforward vector (the curvature of the projection point in the reference reversing trajectory) to ensure that the tractor-trailer system can better track the curve reversing trajectory, so as to meet the needs of different reference reversing trajectories.

[0010] In one embodiment of this application, obtaining the current speed of the tractor and determining the desired throttle opening and / or desired braking pressure based on the current speed and a reference speed of the tractor includes: obtaining the current speed of the tractor and determining the desired acceleration of the tractor based on the current speed and a reference speed of the tractor; calculating the desired throttle opening and / or desired braking pressure based on a preset calibration table, the desired acceleration of the tractor, and the current speed of the tractor. When the desired throttle opening and / or desired braking pressure are determined, the throttle system of the semi-trailer is controlled to operate at the desired throttle opening, and the braking system is controlled to operate at the desired braking pressure, so that the current speed of the tractor remains consistent with the reference speed, thereby achieving speed tracking.

[0011] In one embodiment of this application, between obtaining the current speed of the tractor and determining the desired acceleration of the tractor based on the current speed and a reference speed of the tractor, and calculating the desired throttle opening and / or desired braking pressure based on a preset calibration table, the desired acceleration of the tractor, and the current speed of the tractor, the step of obtaining the current speed of the tractor and determining the desired throttle opening and / or desired braking pressure further includes: obtaining the current gradient of the road on which the tractor is traveling, and compensating the desired acceleration of the tractor based on the current gradient to determine the compensated desired acceleration of the tractor; wherein, the step of calculating the desired throttle opening and / or desired braking pressure based on the preset calibration table, the desired acceleration of the tractor, and the current speed of the tractor includes: calculating the desired throttle opening and / or desired braking pressure based on the preset calibration table, the compensated desired acceleration of the tractor, and the current speed of the tractor. By incorporating the road slope during reversing to compensate for the towing vehicle's desired acceleration, speed tracking under different slopes can be achieved, and precise reversing into parking spaces can be realized based on the reversing reference trajectory.

[0012] In one embodiment of this application, the geometric parameters of the semi-trailer truck train include: the tractor wheelbase, the longitudinal distance between the center of the tractor's rear axle and the tractor-trailer articulation point, and the longitudinal distance between the tractor-trailer articulation point and the center of the trailer's rear axle. By considering the longitudinal distance between the center of the tractor's rear axle and the tractor-trailer articulation point—a crucial factor leading to system nonlinearity—the system error during reversing is reduced, the system stability during reversing is improved, and thus the trajectory following effect during reversing is enhanced.

[0013] As a second aspect of this application, this application also provides a reversing controller for a semi-trailer truck train, comprising: a model building module for building a tractor-trailer kinematic model of the semi-trailer truck train; a data acquisition module for acquiring the current trailer position, the current angle between the tractor and trailer, the current speed of the tractor, the current slope, and a reversing reference trajectory; a lateral controller for calculating the desired front wheel angle of the tractor based on the reversing reference trajectory of the trailer, the current trailer position, the current angle between the tractor and trailer, and the tractor-trailer kinematic model, so as to control the front wheels of the tractor to rotate at the desired front wheel angle; and a longitudinal controller for determining the desired throttle opening and / or desired braking pressure based on the current speed and reference speed of the tractor, so as to control the throttle system of the semi-trailer truck to operate at the desired throttle opening and the braking system to operate at the desired braking pressure.

[0014] As a second aspect of this application, this application also provides a semi-trailer truck train control system, comprising: the semi-trailer truck train reversing controller described above; a front wheel rotation drive system for driving the front wheels of the tractor to rotate at the desired front wheel rotation angle; a throttle system for executing the desired throttle opening; and / or a braking system for executing the desired braking pressure; wherein the semi-trailer truck train reversing controller is communicatively connected to the front wheel rotation drive system, the throttle system, and the braking system, respectively.

[0015] As a third aspect of this application, this application also provides a semi-trailer truck train, including the semi-trailer truck train control system described above. Attached Figure Description

[0016] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain the application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0017] Figure 1 The diagram shown is a flowchart illustrating a reversing control method for a semi-trailer truck train according to an embodiment of this application.

[0018] Figure 2 The diagram shown is a schematic of a semi-trailer truck train system.

[0019] Figure 3 The diagram shown is a flowchart illustrating a reversing control method for a semi-trailer truck train according to another embodiment of this application.

[0020] Figure 4 The diagram shown is a flowchart illustrating a reversing control method for a semi-trailer truck train according to another embodiment of this application.

[0021] Figure 5 The diagram shown is a flowchart illustrating a reversing control method for a semi-trailer truck train according to another embodiment of this application.

[0022] Figure 6 The diagram shown is a flowchart illustrating a reversing control method for a semi-trailer truck train according to another embodiment of this application.

[0023] Figure 7 The diagram shown is a flowchart illustrating a reversing control method for a semi-trailer truck train according to another embodiment of this application.

[0024] Figure 8 The diagram shown is a schematic diagram illustrating the working principle of a semi-trailer truck reversing controller according to an embodiment of this application.

[0025] Figure 9 The diagram shown is a schematic diagram of the working principle of a semi-trailer truck reversing controller provided in another embodiment of this application.

[0026] Figure 10 The diagram shown is a schematic diagram of the working principle of a semi-trailer truck reversing controller provided in another embodiment of this application.

[0027] Figure 11 The diagram shown is a schematic diagram illustrating the working principle of a semi-trailer truck reversing control system according to an embodiment of this application.

[0028] Figure 12 The diagram shown is a schematic diagram of the working principle of a test system provided in an embodiment of this application.

[0029] Figure 13 The figure shown is an example of the curve showing the change of the tractor-trailer angle over time when the tractor-trailer system is laterally controlled using the control method described in this application.

[0030] Figure 14 The image shows the reversing reference trajectory and the actual running trajectory of the trailer when using the reversing control method of this application for the tractor-trailer system for lateral and longitudinal control.

[0031] Figure 15 The diagram shown is a schematic diagram of the working principle of an electronic device provided in an embodiment of this application. Detailed Implementation

[0032] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, top, bottom, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of the components in a specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0033] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] Application Overview A semi-trailer truck train system consists of a tractor and a trailer, which are connected by a traction saddle and a traction pin. The dynamics of a semi-trailer truck train are open-loop stable when traveling forward, but when reversing, even at low speeds, the kinematic model still exhibits nonlinear, unstable, and uncertain characteristics.

[0035] Existing trajectory tracking control technologies for semi-trailer truck systems mostly focus on the forward driving process. During forward driving, except in cases of large steering angles of the tractor's front wheels, the rate of change of the tractor-trailer angle is less than 0, and the overall system tends to be stable. However, because the trend of change of the tractor-trailer angle differs between forward driving and reversing, it exhibits an "asymmetry" in the overall motion. Therefore, during reversing, even without any operation, the rate of change of the tractor-trailer articulation angle is greater than 0, causing the tractor-trailer articulation angle to increase and the overall system to diverge.

[0036] To achieve reverse parking by tracking a predetermined trajectory, the kinematic equations of the semi-trailer truck system are used as a basis. The error between the system's motion trajectory and the reference trajectory is optimized using optimization theory to calculate the control quantity. However, the computational load is too large and cannot meet the real-time requirements of the on-board equipment. Therefore, a hierarchical control method for controlling the reversing of semi-trailer trucks has been proposed. Hierarchical control divides the lateral control into an upper controller and a lower controller. The output of the upper controller is the desired trailer yaw rate, and the input of the lower controller is the desired tractor yaw rate. Although the hierarchical control method reduces the computational load for controlling the reversing of semi-trailer trucks, using the desired trailer yaw rate and the desired tractor yaw rate as the output of the upper controller and the input of the lower controller, respectively, makes it difficult to consider the tractor-trailer angle constraint. Furthermore, the conversion process between the two at low speeds can easily introduce large errors.

[0037] Therefore, this application provides a reversing control method for a semi-trailer truck. Based on the reversing reference trajectory and the trailer's position, the desired front wheel angle of the tractor is calculated to control the front wheels of the tractor to rotate at the desired angle. This allows the tractor-trailer angle to be consistent with the desired angle, achieving path tracking during reversing and thus enabling lateral control of the tractor-trailer system. Simultaneously, the desired throttle opening and / or desired braking pressure are determined based on the tractor's speed and reference speed to control the semi-trailer's throttle system to operate at the desired throttle opening and the braking system to operate at the desired braking pressure. The desired braking pressure is applied to control the actual speed of the tractor unit during reversing, ensuring it remains consistent with the reference speed. This achieves speed tracking and longitudinal control of the tractor-trailer system. Specifically, the semi-trailer reversing control method provided in this application is based on a reversing reference trajectory. It utilizes both speed tracking and path tracking to achieve tracking of the reversing reference trajectory, improving the accuracy of trajectory tracking during reversing and thus enhancing the reversing stability of the semi-trailer. Furthermore, the semi-trailer can achieve precise reversing into position based on the reversing reference trajectory in various application scenarios requiring different reversing speeds.

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0039] As a first aspect of this application, this application provides a method for controlling the reversing of a semi-trailer truck train. Figure 1 The diagram shown is a flowchart illustrating a reversing control method for a semi-trailer truck train according to an embodiment of this application. Figure 1 As shown, the reversing control method for this semi-trailer truck train includes the following steps: Step S1: Construct a tractor-trailer kinematic model, wherein the tractor-semi-trailer kinematic model includes at least the geometric parameters of the semi-trailer truck train.

[0040] Optional, the geometric parameters of the semi-trailer truck train include: The tractor wheelbase, the longitudinal distance between the center of the tractor's rear axle and the tractor-trailer articulation point, and the longitudinal distance between the tractor-trailer articulation point and the center of the trailer's rear axle are all important factors contributing to the nonlinear characteristics of the semi-trailer train system's motion. Therefore, the tractor-trailer kinematic model constructed in this application fully considers the nonlinear characteristics of the semi-trailer train system's motion, reduces system errors, improves system stability, and thus enhances the trajectory following effect during reversing.

[0041] Specifically, Figure 2 The diagram shown is of a semi-trailer truck train system. Figure 2 middle, v : Rear axle center speed of the tractor (not shown); v T : Trailer rear axle center speed (not shown); Φ The angle between the front wheel of the tractor and the longitudinal direction of the tractor; φ The steering angle of the front wheels of the tractor is approximately considered to be... φ = Φ ; θ 1: The heading angle of the tractor unit, that is: the longitudinal direction of the tractor unit relative to the tractor unit's heading angle. x Angle between axes; x , y ): Coordinates of the rear axle center of the tractor in an inertial frame ( x x-axis y (where y is the vertical axis) θ 2: The heading angle of the trailer, that is: the longitudinal direction of the trailer relative to the yaw angle of the trailer. x Angle between axes; ψ The angle between the tractor and trailer is defined as follows: ψ = θ 2- θ 1; ( x T , y T ): The coordinates of the rear axle center of the trailer in an inertial frame; L Tractor wheelbase, which is the longitudinal distance between the center of the front wheel of the tractor and the center of the rear axle of the tractor. L 1: The longitudinal distance between the center of the rear axle of the tractor and the articulation point between the tractor and trailer; L 2: The longitudinal distance between the articulation point of the tractor-trailer and the center of the rear axle of the trailer; k 1: The curvature of the tractor's trajectory; k 2: The curvature of the trailer's trajectory.

[0042] Construct a kinematic model of the tractor unit. The kinematic model of the tractor unit is as follows: in,v : Rear axle center speed of the tractor; θ 1: The heading angle of the tractor unit; φ : The turning angle of the front wheels of the tractor; L Tractor wheelbase Construct a kinematic model of the trailer. The kinematic model of the trailer is as follows: in, θ 2: The heading angle of the trailer; ψ : The angle between the tractor and the trailer; φ : The turning angle of the front wheels of the tractor; L 1: The longitudinal distance between the center of the rear axle of the tractor and the articulation point between the tractor and trailer; L 2: The longitudinal distance between the articulation point of the tractor-trailer and the center of the rear axle of the trailer; L Tractor wheelbase; v : Rear axle center speed of the tractor; v T : Trailer rear axle center speed.

[0043] When constructing the kinematic model of the tractor-trailer, the longitudinal distance between the rear axle center of the tractor and the articulation point of the tractor-trailer was considered. L 1. This is an important factor that leads to the nonlinearity of the system. Therefore, reducing the system error and improving the system stability will improve the trajectory following effect during reversing.

[0044] S2: Obtain the current trailer position and the trailer's reversing reference trajectory; Specifically, the reversing reference trajectory of the trailer is output by the upstream trajectory planning module.

[0045] Specifically, the current trailer pose can include the coordinates of the trailer's rear axle center in the inertial frame. x T , y T ) and the heading angle of the trailer θ 2.

[0046] S3: Based on the trailer's reversing reference trajectory, current trailer position, current angle between the tractor and trailer, and the tractor-trailer kinematic model, calculate the desired front wheel angle of the tractor to control the tractor's front wheels to rotate at the desired front wheel angle. Once the desired front wheel angle of the tractor is calculated, this desired front wheel angle is used to control the front wheels of the tractor to rotate at the desired front wheel angle. This allows the tractor-trailer angle to be consistent with the desired tractor-trailer angle, enabling path tracking during reversing. This allows the tractor-trailer system to travel along the reversing reference trajectory, thus achieving lateral control of the tractor-trailer system.

[0047] S4: Determine the reference speed of the tractor based on the reversing reference trajectory of the trailer; S5: Determine the desired throttle opening and / or desired braking pressure based on the current speed and reference speed of the tractor unit, so as to control the throttle system of the semi-trailer to operate at the desired throttle opening and the braking system to operate at the desired braking pressure.

[0048] When the desired throttle opening and / or desired braking pressure are determined, the throttle system of the semi-trailer is controlled to operate at the desired throttle opening, and the braking system is controlled to operate at the desired braking pressure, so that the current speed of the tractor unit is kept consistent with the reference speed, thereby achieving speed tracking, longitudinal control of the tractor-trailer system can be achieved.

[0049] The semi-trailer truck reversing control method provided in this application is based on a reversing reference trajectory. It uses both speed and path to work together to track the reversing reference trajectory, thereby improving the accuracy of tracking the reference trajectory during reversing and thus improving the reversing stability of the semi-trailer truck. In addition, when the semi-trailer truck is working in application scenarios that require different reversing speeds, it can accurately reverse into position based on the reversing reference trajectory.

[0050] In one embodiment of this application, the lateral control method of the tractor-trailer system using step S3 can adopt the following specific control methods, such as... Figure 3 As shown, S3 (calculating the desired front wheel steering angle of the tractor based on the trailer's reversing reference trajectory, the current trailer position, the current angle between the tractor and trailer, and the tractor-trailer kinematic model) specifically includes the following steps: S31: Calculate the expected angle between the tractor and trailer corresponding to the semi-trailer truck train based on the reversing reference trajectory and the current trailer position; Specifically, such as Figure 2 As shown, the desired angle between the tractor and trailer is calculated based on the reversing reference trajectory and the current trailer position. ψ .

[0051] S32: Based on the tractor-trailer kinematic model, calculate the expected front wheel angle of the tractor according to the current angle between the tractor and the trailer and the expected angle between the tractor and the trailer.

[0052] Specifically, such as Figure 2 As shown, the current angle between the tractor and trailer. ψ This refers to the actual angle between the tractor and the trailer. When the current angle between the tractor and the trailer is determined... ψ and the expected angle between the tractor and trailer ψ Based on the tractor-trailer kinematic model constructed in step S1, the desired front wheel angle of the tractor can be calculated. φ .

[0053] Specifically, if step S32 is calculated by the PID controller, then according to the final value theorem (a method that transforms the calculation of values ​​approaching infinity in the time domain into the calculation of values ​​approaching zero in the complex frequency domain), we know that: in, k P Represents the proportionality coefficient. t Indicates system time. ψ This represents the desired angle between the tractor and the trailer. ψ Indicates the current angle between the tractor and the trailer. L 1 represents the longitudinal distance between the center of the rear axle of the tractor and the articulation point between the tractor and the trailer; L 2 indicates the longitudinal distance between the articulation point of the tractor-trailer and the center of the rear axle of the trailer; L Indicates the wheelbase of the tractor unit; s represents the undamped natural frequency; s represents the complex frequency domain. When the system is stable ψ and ψ The relationship is as follows: Therefore, based on the tractor-trailer kinematic model from step S1, we can conclude that: in, t Indicates system time. φ This indicates the desired front wheel angle of the tractor unit. ψ This represents the desired angle between the tractor and the trailer. ψ Indicates the current angle between the tractor and the trailer. k P Represents the proportionality coefficient. k I Represents the integral coefficient. ψ d This indicates the revised expected angle between the tractor and trailer.

[0054] Optionally, when the desired front wheel angle of the tractor is determined in step S32... φ Then, based on the desired front wheel angle of the tractor. φ When controlling the rotation of the tractor unit, the control limit constraints of the tractor-trailer system need to be considered, including the maximum tractor-trailer angle constraint and the maximum tractor front wheel steering angle constraint, namely: in, ψ min This indicates the minimum allowable angle between the tractor and trailer. ψ max Indicates the maximum permissible angle between the tractor and trailer. φ min This indicates the minimum allowable front wheel angle for the tractor unit. φ max This represents the maximum permissible front wheel angle of the tractor unit. That is, the desired angle between the tractor and trailer calculated according to step S31. ψ To calculate the desired front wheel angle of the tractor φ First, the desired angle between the tractor and trailer determined in step S31 is set. ψ Maximum permissible angle between tractor and trailer ψ max and the minimum allowable angle between the tractor and trailer. ψ min To be determined together, for example, when ψ min ≤ ψ ≤ ψ max If so, then in step S32, the desired angle between the tractor and trailer determined in step S31 will be used. ψ To directly calculate the expected front wheel angle of the tractor φ .when ψ min > ψ If so, then in step S32, the minimum allowable angle between the tractor and trailer is used. ψ min To directly calculate the expected front wheel angle of the tractor φ .when ψ > ψmax If so, then in step S32, the maximum allowable angle between the tractor and trailer is used. ψ max To directly calculate the expected front wheel angle of the tractor φ .

[0055] Optional, such as Figure 4 As shown, step S31 (calculating the expected angle between the tractor and trailer corresponding to the semi-trailer truck train based on the reversing reference trajectory and the current trailer position) includes the following steps: S311: Obtain the longitudinal distance between the center of the rear axle of the tractor and the articulation point between the tractor and trailer. L 1. The longitudinal distance between the tractor-trailer articulation point and the center of the trailer's rear axle. L 2; Specifically, based on the kinematic models of the tractor and trailer in step S1, the tractor-trailer angle can be determined. ψ The differential equation is as follows: in, φ Indicates the steering angle of the front wheels of the tractor unit. L 1 represents the longitudinal distance between the center of the rear axle of the tractor and the articulation point between the tractor and the trailer; L 2 indicates the longitudinal distance between the articulation point of the tractor-trailer and the center of the rear axle of the trailer; L Indicates the wheelbase of the tractor unit; ψ Indicates the angle between the tractor and the trailer; exist φ =0 and ψ Linearizing the above equation at the point = 0, we have: S312: Calculate the normal distance between the center of the trailer's rear axle and the projection point based on the reversing reference trajectory and the current trailer position. e d And the difference between the trailer's heading angle and the projection point's heading angle. e θ The projection point is the trajectory point on the reversing reference trajectory with the shortest straight-line distance to the center of the trailer's rear axle; Specifically, the normal distance between the center of the trailer's rear axle and the projection point. e d That is, the lateral error of the trailer. e d The difference between the trailer's heading angle and the heading angle of the projection point. e θ That is, the heading error of the trailer. e θ .

[0056] Among them, heading error e θ The calculation formula is as shown in equation (1). ： Equation (I), in Equation (I), θ 2 indicates the heading angle of the trailer. θ r This indicates the heading angle of the projection point.

[0057] Differentiating both sides of equation (i), we get: in, k r Indicates the curvature of the projection point. v T Indicates the speed at the center of the rear axle of the trailer. ψ Indicates the angle between the tractor and the trailer. L Indicates the wheelbase of the tractor unit. L 1 represents the longitudinal distance between the center of the rear axle of the tractor and the articulation point between the tractor and trailer. L 2 indicates the longitudinal distance between the articulation point of the tractor-trailer and the center of the trailer's rear axle. φ Indicates the steering angle of the front wheels of the tractor unit; lateral error e d The calculation formula is as shown in equation (II): Equation (II), in equation (II), X This represents the vector indicating the center position of the rear axle of the trailer. X =( x T , y T ); X r Represents the position vector of the projection point. X r =( x r , y r ); n r This represents the normal vector of the projected point line. n r =(-sin θ r cos θ r ).

[0058] Differentiating both sides of equation (ii), we get: in,v T Indicates the speed at the center of the rear axle of the trailer. e θ Indicates heading error. θ 2 indicates the heading angle of the trailer. θ r This indicates the heading angle of the projection point.

[0059] Therefore, the state-space equation of the trailer is as follows: From the kinematic model of the tractor-trailer in step S1, it can be seen that, under steady state, the angle between the tractor and trailer is... ψ and front wheel cornering φ The relationship between them is as follows: Linearizing the above equation at φ=0 and ψ=0, we get: The simplified state-space equations are as follows: S313: Calculate the expected angle between the tractor and trailer for the semi-trailer truck train based on the normal distance between the center of the trailer's rear axle and the projection point, the difference between the heading angle of the trailer and the heading angle of the projection point, the curvature of the projection point, the longitudinal distance between the center of the tractor's rear axle and the tractor-trailer articulation point, and the longitudinal distance between the tractor-trailer articulation point and the center of the trailer's rear axle.

[0060] When the lateral error is determined in step S312 e d and heading error e θ Then, based on the lateral error e d and heading error e θ Calculate the desired tractor-trailer angle to ensure that the tractor-trailer system can eliminate lateral and heading errors as quickly as possible.

[0061] Specifically, the expected angle between the tractor and trailer. The calculation formula is as follows: In the formula, Represents the system state vector. Represents the system feedback vector. This represents the lateral error coefficient. This represents the heading error proportionality coefficient. e d Indicates lateral error. eθ This indicates the heading error.

[0062] Optional, such as Figure 5 As shown, after step S313, step S31 (calculating the desired angle between the tractor and trailer based on the reversing reference trajectory and the current trailer position) further includes the following steps: Step S314: Determine the curvature of the projection point based on the reversing reference trajectory of the trailer; Step S315: Based on the curvature of the projection point, compensate for the desired angle between the tractor and the trailer to determine the compensated desired angle between the tractor and the trailer. After step S315, the desired angle between the tractor and trailer. The calculation formula is as follows: , In the formula, Represents the system state vector. Represents the system feedback vector. This represents the lateral error coefficient. This represents the heading error proportionality coefficient. e d Indicates lateral error. e θ Indicates heading error. δψ Represents the system feedforward term. This represents the curvature of the projection point. The system feedback vector includes the lateral error. e d and heading error e θ The system feedforward term includes the curvature of the projected points in the reversing reference trajectory.

[0063] Calculating the expected angle between the tractor and trailer At the same time, the desired tractor-trailer angle is compensated based on the system feedforward vector (the curvature of the projection point in the reference reversing trajectory) to ensure that the tractor-trailer system better tracks the curved reversing trajectory, thereby meeting the requirements of different reference reversing trajectories. This achieves compensation for state variables and improves the dynamic response characteristics of the semi-trailer truck train system.

[0064] In this case, step S32 (obtaining the current angle between the tractor and trailer, and calculating the expected front wheel angle of the tractor based on the tractor-trailer kinematic model, according to the current angle and the expected angle of the tractor and trailer) includes: Step S321: Obtain the compensated expected angle between the tractor and trailer, and based on the tractor-trailer kinematic model, calculate the expected front wheel angle of the tractor according to the current angle between the tractor and trailer and the compensated expected angle between the tractor and trailer.

[0065] That is, the expected front wheel angle of the tractor is calculated based on the expected angle between the tractor and the trailer obtained after compensation.

[0066] In another embodiment of this application, the longitudinal control method of the tractor-trailer system using step S5 can adopt the following specific control methods, such as... Figure 6 As shown, step S5 (obtaining the current speed of the tractor and determining the desired throttle opening and / or desired braking pressure based on the current speed and the reference speed of the tractor) specifically includes the following steps: Step S51: Obtain the current speed of the tractor and determine the desired acceleration of the tractor based on the current speed of the tractor and the reference speed of the tractor. Specifically, the reference speed of the tractor can be determined based on the reversing reference trajectory.

[0067] Step S52: Calculate the desired throttle opening and / or desired braking pressure based on the preset calibration table, the desired acceleration of the tractor, and the current speed of the tractor.

[0068] Since the desired throttle opening / brake pressure is a function of the tractor speed and tractor acceleration, the desired throttle opening / brake pressure can be obtained by interpolation based on the preset calibration table, the desired tractor acceleration, and the current tractor speed.

[0069] When the desired throttle opening and / or desired braking pressure are determined, the throttle system of the semi-trailer is controlled to operate at the desired throttle opening, and the braking system is controlled to operate at the desired braking pressure, so that the current speed of the tractor unit is kept consistent with the reference speed, thereby achieving speed tracking.

[0070] Optional, such as Figure 7 As shown, between S51 and S52, S5 (obtaining the current speed of the tractor and determining the desired throttle opening and / or desired braking pressure based on the current speed of the tractor and the reference speed of the tractor) also includes the following steps: S510: Obtain the current gradient of the road on which the tractor is traveling, and compensate the expected acceleration of the tractor based on the current gradient to determine the expected acceleration of the tractor after compensation. S52: Based on the preset calibration table, the desired acceleration of the tractor, and the current speed of the tractor, calculate the desired throttle opening and / or the desired braking pressure, including: Step S520: Calculate the desired throttle opening and / or desired braking pressure based on the preset calibration table, the desired acceleration of the tractor after compensation, and the current speed of the tractor.

[0071] By incorporating the road slope during reversing to compensate for the towing vehicle's desired acceleration, speed tracking under different slopes can be achieved, and precise reversing into parking spaces can be realized based on the reversing reference trajectory.

[0072] Exemplary controller As a second aspect of this application, this application also provides a reversing controller for a semi-trailer truck train. Figure 8 The diagram shown is a schematic diagram illustrating the working principle of a semi-trailer truck reversing controller according to an embodiment of this application. Figure 8 As shown, the semi-trailer truck reversing controller 1 includes: Model building module 10 is used to build the kinematic model of the tractor-trailer; The data acquisition module 20 is used to acquire the current trailer position, the current angle between the tractor and the trailer, the current speed of the tractor, the current slope, and the reversing reference trajectory; that is, the data acquisition module 20 is used to execute step S2 (acquiring the current trailer position and the trailer reversing reference trajectory) and step S4 (determining the reference speed of the tractor based on the trailer's reversing reference trajectory) in the semi-trailer truck reversing control method described above.

[0073] Specifically, the current trailer position may include, but is not limited to: the coordinates of the trailer rear axle center in the inertial frame ( x T , y T ) and the heading angle of the trailer θ 2.

[0074] Specifically, the reversing reference trajectory can be output by the upstream trajectory planning module. Therefore, the data acquisition module 20 is communicatively connected to the upstream trajectory planning module and the trailer pose detector.

[0075] The lateral controller 30 is used to calculate the desired front wheel angle of the tractor based on the trailer's reversing reference trajectory, the current trailer position, the current angle between the tractor and trailer, and the tractor-trailer kinematic model, so as to control the front wheels of the tractor to rotate at the desired front wheel angle; that is, the lateral controller 30 executes step S3 in the semi-trailer train reversing control method described above (calculating the desired front wheel angle of the tractor based on the trailer's reversing reference trajectory and the current trailer position, so as to control the front wheels of the tractor to rotate at the desired front wheel angle). After the desired front wheel angle of the tractor is calculated, the desired front wheel angle is used to control the front wheels of the tractor to rotate at the desired front wheel angle, thereby controlling the tractor-trailer angle to be consistent with the desired tractor-trailer angle, realizing path tracking during the reversing process, so that the tractor-trailer system travels along the reversing reference trajectory, thus realizing lateral control of the tractor-trailer system.

[0076] The longitudinal controller 40 is used to determine the desired throttle opening and / or desired braking pressure based on the current speed and reference speed of the tractor unit, so as to control the throttle system of the semi-trailer truck to operate at the desired throttle opening and the braking system to operate at the desired braking pressure. That is, the longitudinal controller 40 is used to execute step S5 in the semi-trailer truck reversing control method described above (obtaining the current speed of the tractor unit, and determining the desired throttle opening and / or desired braking pressure based on the current speed and reference speed of the tractor unit, so as to control the throttle system of the semi-trailer truck to operate at the desired throttle opening and the braking system to operate at the desired braking pressure).

[0077] When the desired throttle opening and / or desired braking pressure are determined, the throttle system of the semi-trailer is controlled to operate at the desired throttle opening, and the braking system is controlled to operate at the desired braking pressure, so that the current speed of the tractor unit is kept consistent with the reference speed, thereby achieving speed tracking, longitudinal control of the tractor-trailer system can be achieved.

[0078] Optional, such as Figure 9 As shown, the horizontal controller 30 specifically includes: a first upper-level controller 31 and a first lower-level controller 32, wherein the first upper-level controller 31 is used to execute the above... Figure 3 In the semi-trailer truck reversing control method, step S31 involves the first upper-level controller 31 calculating the desired angle between the tractor and trailer based on the reversing reference trajectory and the current trailer position. The first lower-level controller 32 executes the above steps. Figure 3 In the semi-trailer truck reversing control method, step S32, namely the first lower-level controller 32, is used to obtain the current angle between the tractor and the trailer, and calculate the expected front wheel angle of the tractor based on the kinematic model of the tractor and the expected angle between the tractor and the trailer.

[0079] The vertical controller 40 specifically includes a second upper-level controller 41 and a second lower-level controller 42, wherein the second upper-level controller 41 is used to execute the above... Figure 6 In step S51 of the semi-trailer truck reversing control method described above, the second upper-level controller 41 is used to acquire the current speed of the tractor and determine the desired acceleration of the tractor based on the current speed and the reference speed of the tractor. The second lower-level controller 42 is used to execute the above... Figure 7 In step S52 of the semi-trailer truck reversing control method shown above, the second lower-level controller 42 is used to calculate the desired throttle opening and / or desired braking pressure based on a preset calibration table, the desired acceleration of the tractor, and the current speed of the tractor.

[0080] Specifically, such as Figure 10As shown, the first upper-level controller 31 specifically includes: a feedback controller 311 and a feedforward controller 312.

[0081] The feedback controller 311 is used to perform the above. Figure 4 In the semi-trailer truck reversing control method described above, steps S311-S313, namely, the feedback controller 311, is used to obtain the longitudinal distance between the rear axle center of the tractor and the tractor-trailer articulation point in the current trailer position. L 1. The longitudinal distance between the tractor-trailer articulation point and the center of the trailer's rear axle. L 2. Based on the reversing reference trajectory and the current trailer position, calculate the normal distance between the center of the trailer's rear axle and the projection point. e d And the difference between the trailer's heading angle and the projection point's heading angle. e θ The projection point is the trajectory point on the reversing reference trajectory with the shortest straight-line distance to the center of the trailer's rear axle; and the expected angle between the tractor and trailer is calculated based on the normal distance between the center of the trailer's rear axle and the projection point, the difference between the trailer's heading angle and the projection point's heading angle, the curvature of the projection point, the longitudinal distance between the center of the tractor's rear axle and the tractor-trailer articulation point, and the longitudinal distance between the tractor-trailer articulation point and the center of the trailer's rear axle. That is, the feedback controller 301 can obtain the lateral error through calculation. e d and heading error e θ And based on the lateral error e d and heading error e θ Calculate the desired tractor-trailer angle to ensure that the tractor-trailer system can eliminate lateral and heading errors as quickly as possible.

[0082] The feedforward controller 312 is used to perform Figure 5 In the semi-trailer truck reversing control method, steps S314-S315 involve the feedforward controller 312 determining the curvature of the projection point based on the trailer's reversing reference trajectory; and compensating for the desired angle between the tractor and trailer based on the projection point curvature to determine the compensated desired angle between the tractor and trailer; that is, calculating the desired angle between the tractor and trailer. At the same time, the feedforward controller 312 compensates for the desired tractor-trailer angle based on the system feedforward vector (the curvature of the projection point in the reference reversing trajectory) to ensure that the tractor-trailer system better tracks the curved reversing trajectory, so as to meet the needs of different reference reversing trajectories.

[0083] As a third aspect of this application, this application also provides a semi-trailer truck train control system, such as... Figure 11As shown, the control system includes: the aforementioned semi-trailer truck reversing controller 1; a front wheel rotation drive system 2 for driving the front wheels of the tractor to rotate at a desired front wheel angle; a throttle system 3 for executing a desired throttle opening; and / or a braking system 4 for executing a desired braking pressure; wherein the semi-trailer truck reversing controller 1 is communicatively connected to the front wheel rotation drive system 2, the throttle system 3, and the braking system 4, respectively. After determining the desired throttle opening and / or the desired braking pressure, the semi-trailer truck reversing controller 1 transmits the desired throttle opening and the desired braking pressure to the throttle system 3 and the braking system 4, respectively. The throttle system 3 controls the throttle opening according to the desired throttle opening, and the braking system 4 controls the braking pressure of the braking mechanism according to the desired braking pressure. Simultaneously, after determining the desired front wheel angle of the tractor, the semi-trailer truck reversing controller 1 transmits the desired front wheel angle of the tractor to the front wheel rotation drive system 2, and the front wheel rotation drive system 2 controls the front wheel rotation according to the desired front wheel angle.

[0084] To quickly verify the reversing control method for semi-trailer trucks proposed in this application, the method was tested and verified using simulation methods. Figure 12 The diagram shown illustrates the working principle of the testing system. Figure 12 As shown, the test system includes: a trajectory planning module 704, an angle / velocity sensor module 701, a positioning module 703, a controller simulation module 702, and a semi-trailer train dynamics simulation module 705. The trajectory planning module 704, the angle / velocity sensor module 701, and the positioning module 703 are all communicatively connected to the controller simulation module 702, and the angle / velocity sensor module 701 and the positioning module 703 are all communicatively connected to the semi-trailer train dynamics simulation module 705. Among them, the trajectory planning module 704 is used to simulate the upstream trajectory planning module, output the reversing reference trajectory, and send the reversing reference trajectory to the controller simulation module 702; The positioning module 703 is used to locate the pose information of the semi-trailer truck train system in real time, such as the coordinates of the rear axle center of the tractor in the inertial frame. x , y The coordinates of the rear axle center of the trailer in the inertial frame ( x T , y T The longitudinal distance between the center of the front wheel of the tractor and the center of the rear axle of the tractor. L Longitudinal distance between the center of the rear axle of the tractor and the articulation point between the tractor and trailer. L 1; Longitudinal distance between the tractor-trailer articulation point and the center of the trailer's rear axle L 2; The angle / speed sensor module 701 is used to detect the speed information of the semi-trailer train system and the angle information such as the angle between the tractor and the trailer in real time, for example: the center speed of the rear axle of the tractor. v Trailer rear axle center speed v T ， Angle between the front wheel of the tractor and the longitudinal direction of the tractor Φ ; Tractor front wheel steering angle φ The heading angle of the tractor θ 1. Trailer heading angle θ 2. Real-time angle between tractor and trailer ψ ; The controller simulation module 702 calculates the desired front wheel angle, desired throttle opening, and / or desired braking pressure of the tractor vehicle based on the pose information transmitted by the positioning module 703, the speed and angle information transmitted by the angle / speed sensor module 701, and the reversing reference trajectory transmitted by the trajectory planning module 704. It then transmits these parameters to the semi-trailer train dynamics simulation module 705. Specifically, the calculation method for the desired front wheel angle, desired throttle opening, and / or desired braking pressure of the tractor vehicle by the controller simulation module 702 is as described in steps S1-S5 of the semi-trailer train reversing control method above, and will not be repeated here.

[0085] The semi-trailer train dynamics simulation module 705 performs dynamics simulations based on the tractor's desired front wheel steering angle, desired throttle opening, and / or desired braking pressure, and outputs the trailer's running trajectory, for example... Figure 14 As shown. From Figure 14 As can be seen, after using the above-described semi-trailer train reversing control method to control the lateral and longitudinal aspects of the tractor-trailer system, the actual running trajectory of the trailer rear axle center has a high degree of overlap with the reversing reference trajectory, and can effectively complete the reversing trajectory tracking task.

[0086] Specifically, when testing and verifying the method for reversing a semi-trailer truck train proposed in this application using the simulation methods described above, the lateral control of the tractor-trailer system (after calculating the desired front wheel angle of the tractor, this desired front wheel angle is used to control the front wheels of the tractor to rotate at the desired front wheel angle, thereby controlling the tractor-trailer angle to be consistent with the desired tractor-trailer angle, realizing path tracking during reversing) was tested and verified. The curve of the tractor-trailer angle changing with time in the test and verification results is shown below. Figure 13 As shown. Desired angle between tractor and trailer. The actual angle between the tractor and trailer is 0° at time 0, which is 30°. The tractor wheelbase is... LThe longitudinal distance between the center of the rear axle of the tractor and the articulation point of the tractor and trailer is 4 m. L 1 The longitudinal distance between the tractor-trailer articulation point and the center of the trailer's rear axle is 0.5 m. L 2 is 14 m, and the curve of the angle between the tractor and trailer changing over time is as follows: Figure 13 As shown. From Figure 13 As can be seen, when laterally controlling the tractor-trailer system (i.e., laterally controlling the front wheels of the tractor to rotate at the desired front wheel angle based on the desired front wheel angle), the actual angle between the tractor and trailer can be kept consistent with the reference angle between the tractor and trailer. This means that the tractor-trailer angle can be well controlled, thus ensuring that the tractor-trailer angle matches the desired angle. This enables path tracking during reversing, allowing the tractor-trailer system to travel along the reversing reference trajectory, thereby achieving lateral control of the tractor-trailer system.

[0087] When testing and verifying the reversing control method for a semi-trailer truck proposed in this application using the simulation methods described above, the lateral and longitudinal control of the tractor-trailer system were tested and verified. The reversing reference trajectory and trailer running trajectory in the test and verification results are as follows: Figure 14 As shown. Initially, the lateral error is 1 m, the heading error is 5°, the actual tractor-trailer angle at time 0 is 0°, the tractor wheelbase L is 4 m, the longitudinal distance L1 between the tractor rear axle center and the tractor-trailer articulation point is 0.5 m, and the longitudinal distance L2 between the tractor-trailer articulation point and the trailer rear axle center is 14 m. The reversing reference trajectory and trailer running trajectory are as follows: Figure 14 As shown. From Figure 14 As can be seen, after using the above-described semi-trailer train reversing control method to control the lateral and longitudinal aspects of the tractor-trailer system, the actual running trajectory of the trailer rear axle center has a high degree of overlap with the reversing reference trajectory, and can effectively complete the reversing trajectory tracking task.

[0088] Exemplary semi-trailer This application also provides a semi-trailer truck train, including the semi-trailer truck train control system described above.

[0089] Exemplary electronic devices Below, for reference Figure 15 This describes an electronic device according to embodiments of the present application. Figure 15 The diagram shown is a structural schematic of an electronic device provided in an embodiment of this application.

[0090] like Figure 15 As shown, the electronic device 600 includes one or more processors 601 and memory 602.

[0091] The processor 601 may be a central processing unit (CPU) or other form of processing unit with information processing and / or information execution capabilities, and may control other components in the electronic device 600 to perform desired functions.

[0092] The memory 601 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program information may be stored on the computer-readable storage medium, and the processor 601 may run the program information to implement the semi-trailer truck reversing control method of the various embodiments of this application described above, or other desired functions.

[0093] In one example, the electronic device 600 may also include an input device 603 and an output device 604, which are interconnected via a bus system and / or other forms of connection mechanism (not shown).

[0094] The input device 603 may include, for example, a keyboard, a mouse, etc.

[0095] The output device 604 can output various information to the outside. The output device 604 may include, for example, a display, a communication network, and remote output devices connected thereto.

[0096] Of course, for the sake of simplicity, Figure 15 Only some of the components of the electronic device 600 relevant to this application are shown in this illustration; components such as buses, input / output interfaces, etc., are omitted. In addition, the electronic device 600 may include any other suitable components depending on the specific application.

[0097] In addition to the methods and devices described above, embodiments of this application may also be computer program products, which include computer program information that, when run by a processor, causes the processor to perform the steps in the semi-trailer truck reversing control method according to various embodiments of this application as described in this specification.

[0098] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Python and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0099] Furthermore, embodiments of this application may also be computer-readable storage media storing computer program information thereon, which, when run by a processor, causes the processor to execute the steps in the semi-trailer truck reversing control method according to various embodiments of this application.

[0100] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0101] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0102] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0103] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. Such disassembly and / or recombination should be considered as equivalent to the present application.

[0104] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features of the invention herein.

[0105] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Any modifications or equivalent substitutions made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. A method for controlling the reversing of a semi-trailer truck train, characterized in that, include: Construct a tractor-trailer kinematic model of a semi-trailer truck train, wherein the tractor-semi-trailer kinematic model includes at least the geometric parameters of the semi-trailer truck train. Obtain the current trailer position and the trailer's reversing reference trajectory; Based on the trailer's reversing reference trajectory, the current trailer position, the current angle between the tractor and trailer, and the tractor-trailer kinematic model, the desired front wheel angle of the tractor is calculated to control the front wheels of the tractor to rotate at the desired front wheel angle. The reference speed of the tractor is determined based on the reversing reference trajectory of the trailer; The current speed of the tractor is obtained, and the desired throttle opening and / or desired braking pressure are determined based on the current speed and reference speed of the tractor, so as to control the throttle system of the semi-trailer to operate at the desired throttle opening and the braking system to operate at the desired braking pressure. The geometric parameters of the semi-trailer include: the wheelbase of the tractor, the longitudinal distance between the center of the rear axle of the tractor and the articulation point of the tractor and trailer, and the longitudinal distance between the articulation point of the tractor and the center of the rear axle of the trailer.

2. The control method according to claim 1, characterized in that, The step of calculating the desired front wheel steering angle of the tractor based on the trailer's reversing reference trajectory, the current trailer position, the current angle between the tractor and trailer, and the tractor-trailer kinematic model includes: Based on the reversing reference trajectory and the current trailer position, calculate the expected angle between the tractor and trailer corresponding to the semi-trailer truck train; Based on the tractor-trailer kinematic model, the desired front wheel angle of the tractor is calculated according to the current angle between the tractor and the trailer and the desired angle between the tractor and the trailer.

3. The control method according to claim 2, characterized in that, The step of calculating the expected angle between the tractor and trailer corresponding to the semi-trailer truck train based on the reversing reference trajectory and the current trailer position includes: Obtain the longitudinal distance between the center of the rear axle of the tractor and the articulation point between the tractor and the trailer, and the longitudinal distance between the articulation point between the tractor and the trailer and the center of the rear axle of the trailer; Based on the reversing reference trajectory and the current trailer position, calculate the normal distance between the center of the trailer's rear axle and the projection point, as well as the difference between the trailer's heading angle and the projection point's heading angle, wherein the projection point is the trajectory point on the reversing reference trajectory with the shortest straight-line distance to the center of the trailer's rear axle. The expected angle between the tractor and trailer for the semi-trailer truck train is calculated based on the normal distance between the rear axle center of the trailer and the projection point, the difference between the heading angle of the trailer and the heading angle of the projection point, the curvature of the projection point, the longitudinal distance between the rear axle center of the tractor and the tractor-trailer articulation point, and the longitudinal distance between the tractor-trailer articulation point and the rear axle center of the trailer.

4. The control method according to claim 3, characterized in that, After calculating the expected angle between the tractor and trailer corresponding to the semi-trailer train based on the normal distance between the trailer's rear axle center and the projection point, the difference between the trailer's heading angle and the projection point's heading angle, the curvature of the projection point, the longitudinal distance between the tractor's rear axle center and the tractor-trailer articulation point, and the longitudinal distance between the tractor-trailer articulation point and the trailer's rear axle center, the calculation of the expected angle between the tractor and trailer corresponding to the semi-trailer train based on the reversing reference trajectory and the current trailer position further includes: The curvature of the reversing reference trajectory is determined based on the reversing reference trajectory of the trailer; Based on the curvature of the reversing reference trajectory, the desired angle between the tractor and trailer is compensated to determine the compensated desired angle between the tractor and trailer. The step of calculating the desired front wheel angle of the tractor based on the tractor-trailer kinematic model, according to the current angle between the tractor and trailer and the desired angle between the tractor and trailer, includes: Obtain the compensated expected angle between the tractor and trailer, and based on the kinematic model of the tractor and trailer, calculate the expected front wheel angle of the tractor according to the current angle between the tractor and trailer and the compensated expected angle between the tractor and trailer.

5. The control method according to claim 1, characterized in that, The step of obtaining the current speed of the tractor and determining the desired throttle opening and / or desired braking pressure based on the current speed of the tractor and a reference speed of the tractor includes: The current speed of the tractor is obtained, and the desired acceleration of the tractor is determined based on the current speed of the tractor and the reference speed of the tractor. Based on the preset calibration table, the desired acceleration of the tractor, and the current speed of the tractor, calculate the desired throttle opening and / or desired braking pressure.

6. The control method according to claim 5, characterized in that, Between obtaining the current speed of the tractor and determining the desired acceleration of the tractor based on the current speed and a reference speed of the tractor, and calculating the desired throttle opening and / or desired braking pressure based on a preset calibration table, the desired acceleration of the tractor, and the current speed of the tractor, the step of obtaining the current speed of the tractor and determining the desired throttle opening and / or desired braking pressure based on the current speed and a reference speed of the tractor further includes: The current gradient of the road on which the tractor is traveling is obtained, and the expected acceleration of the tractor is compensated according to the current gradient to determine the expected acceleration of the tractor after compensation. The step of calculating the desired throttle opening and / or desired braking pressure based on a preset calibration table, the desired acceleration of the tractor, and the current speed of the tractor includes: Based on the preset calibration table, the expected acceleration of the tractor after compensation, and the current speed of the tractor, the expected throttle opening and / or expected braking pressure are calculated.

7. A reversing controller for a semi-trailer truck train, characterized in that, include: The model building module is used to build the tractor-trailer kinematic model of a semi-trailer truck train. The data acquisition module is used to acquire the current trailer position, the current angle between the tractor and the trailer, the current speed of the tractor, the current slope, and the reversing reference trajectory. A lateral controller is used to calculate the desired front wheel turning angle of the tractor based on the reversing reference trajectory of the trailer, the current trailer position, the current angle between the tractor and the trailer, and the kinematic model of the tractor and the trailer, so as to control the front wheels of the tractor to rotate at the desired front wheel turning angle. A longitudinal controller is used to determine a desired throttle opening and / or a desired braking pressure based on the current speed of the tractor and a reference speed of the tractor, so as to control the throttle system of the semi-trailer to operate at the desired throttle opening and the braking system to operate at the desired braking pressure. The geometric parameters of the semi-trailer include: the wheelbase of the tractor, the longitudinal distance between the center of the rear axle of the tractor and the articulation point between the tractor and the trailer, and the longitudinal distance between the articulation point between the tractor and the rear axle of the trailer.

8. A semi-trailer train control system, characterized in that, include: The semi-trailer truck reversing controller as described in claim 7; A front wheel rotation drive system for driving the front wheels of the tractor to rotate at the desired front wheel angle; Throttle system for executing the desired throttle opening; and / or Braking system for applying the desired braking pressure; The semi-trailer truck reversing controller is communicatively connected to the front wheel rotation drive system, the throttle system, and the braking system.

9. A semi-trailer truck train, characterized in that, Including the semi-trailer truck as described in claim 8.

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