SPEED CONTROL PROCEDURES

Abstract

Speed ​​control procedures that include: Determine that a host vehicle (10) is traveling downhill; Determining an instruction of axle torque to maintain a predetermined following distance (38) from the host vehicle (10) to a lead vehicle (40) while the host vehicle (10) travels downhill along a roadway (48), the lead vehicle (40) being immediately in front of the host vehicle (10), the instruction of axle torque being a function of a roadway gradient, the roadway (48) having a road surface (50) and the roadway gradient being an angle from the road surface (50) to a virtual horizontal line (52); Determine that a brake of the host vehicle (10) is applied to provide the previously determined instruction of axle torque; Comparing the axle torque instruction with a braking termination threshold to determine whether the axle torque instruction is greater than the braking termination threshold; Comparing, in response to determining that the axle torque instruction is greater than the threshold to stop braking, a current following distance between the host vehicle (10) and the lead vehicle (40) with a threshold to exit following operation, to determine whether the current following distance between the host vehicle (10) and the lead vehicle (40) is greater than the threshold to exit following operation; and Instructing the host vehicle (10) to release its brakes in response to the determination that the current following distance between the host vehicle (10) and the lead vehicle (40) is greater than the threshold for exiting pursuit operations to stop braking.

Description

INTRODUCTION

[0001] This disclosure relates to adaptive speed control. Specifically, this disclosure describes a system and a method for downhill tracking operation control using speed control. For prior art, reference is made to DE 10 2005 015 819 A1, DE 600 16 500 T2, DE 10 2016 012 414 A1 and DE 11 2020 003 601 T5.

[0002] This introduction presents the content of the disclosure in general terms. Neither the work of the inventors currently named, to the extent described in this introduction, nor those aspects of the description that cannot otherwise qualify as prior art at the time of filing, are expressly or implicitly recognized as prior art contrary to this disclosure. When a host vehicle travels downhill, maintaining a following distance between the host vehicle and a lead vehicle is difficult due to the use of two actuators (i.e., the propulsion and braking systems) and the gravitational forces resulting from the gradient of the road. Because two actuators are involved during the downhill movement of the host vehicle, two actuation control instructions are necessary to maintain the following distance between the host vehicle and the lead vehicle.If this following distance is maintained, gravitational forces cause the host vehicle 10 to accelerate towards the lead vehicle. If the roadway is sufficiently steep and long, braking may be necessary to maintain the following distance between the host vehicle and the lead vehicle. Once the desired following distance is reached, the braking instruction is terminated, and the host vehicle accelerates again towards the lead vehicle. However, this braking and acceleration cycle causes, among other things, driver discomfort and an oscillating control of the following distance. It is therefore desirable to develop a method and a system to maintain the following distance between the host vehicle 10 and the lead vehicle in such a way as to avoid the oscillatory nature of the braking and acceleration cycles. SUMMARY

[0003] The present invention is defined by the features of the accompanying independent claim 1. Advantageous embodiments are specified in the following description and in the dependent claims.

[0004] The present disclosure describes a speed control method. The speed control method also includes determining that a host vehicle is traveling downhill and determining the instruction of an axle torque to maintain a predetermined following distance from the host vehicle to a lead vehicle while the host vehicle travels downhill along a roadway. The lead vehicle is located immediately in front of the host vehicle. The instruction of the axle torque is a function of the roadway gradient. The roadway has a road surface. The roadway gradient is the angle of the road surface to a virtual horizontal line.The procedure further comprises determining that a brake on the host vehicle is applied to provide the previously determined axle torque instruction, and comparing the axle torque instruction with a braking termination threshold to determine whether the axle torque instruction is greater than the braking termination threshold. In response to determining that the axle torque instruction is greater than the braking termination threshold, the procedure further comprises comparing the following distance between the host vehicle and the lead vehicle with a tracking exit threshold to determine whether the following distance between the host vehicle and the lead vehicle is greater than the tracking exit threshold.The method, in response to determining that the current following distance between the host vehicle and the lead vehicle is greater than the threshold for exiting following operation, also includes instructing the host vehicle to release its brakes to terminate braking. Further embodiments of this aspect include appropriate computer systems, devices, and computer programs recorded in one or more computer storage devices, each configured to perform the actions of the method. The method described in this paragraph improves vehicle technology by maintaining a predetermined distance between the host vehicle and a lead vehicle when the host vehicle is traveling downhill and by employing speed control, thereby minimizing the risk of the host vehicle making contact with the lead vehicle while traveling downhill.

[0005] According to some aspects of the present disclosure, the speed control method may include determining the instruction for a maximum axle torque. The instruction for the maximum torque is a function of the road gradient. Furthermore, in response to determining that the instruction for the axle torque is not greater than the threshold for ending braking, the method includes limiting the instruction for the axle torque to the instruction for the maximum axle torque. The speed delta is the difference between the speed of the lead vehicle and the speed of the host vehicle. The speed control method may include comparing the speed delta with a lead speed threshold to determine whether the speed delta is greater than the lead speed threshold.The speed control procedure may, in response to determining that the speed delta is greater than the guide speed threshold, further include determining that the braking termination threshold is equal to a difference between an initial braking termination threshold and a deceleration offset value. The speed control procedure may, in response to determining that the speed delta is greater than the guide speed threshold, further include determining that the tracking exit threshold is equal to a difference between an initial tracking exit threshold and a tracking exit offset value.The speed control procedure may, in response to determining that the speed delta is not greater than the leading speed threshold, include determining that the braking termination threshold is equal to an initial braking termination threshold. The speed control procedure may, in response to determining that the speed delta is not greater than the leading speed threshold, include determining that the exit tracking threshold is equal to an initial exit tracking threshold. The axle torque instruction is a function of the specified following distance from the host vehicle to the lead vehicle. The vehicle is attached to a trailer. The axle torque instruction is determined using the following equation: AxCommand=K1*HDerr+K2*ΔHDerr−mg*sin(θ) where: m is the mass of the vehicle plus the mass of the trailer; K1 is a first calibration factor; K2 is a second calibration factor; g is the gravitational constant; V is the speed of the host vehicle; HT is the tracking operating time selected by the driver; HD is the specified following distance (V*HT) from the host vehicle to the lead vehicle; L is the measured distance from the host vehicle to the lead vehicle; HD err The tracking operation error HD - L is; θ is the angle from the road surface to the virtual horizontal line; and ΔHD err This is a first derivation of the tracking operational error with respect to time.

[0006] The present disclosure further describes a vehicle comprising sensors, a propulsion system, a braking system, and a controller. The controller communicates with the sensors, the braking system, and the propulsion system and is programmed to execute the procedure described above.

[0007] The present disclosure also describes a material non-transient machine-readable medium containing machine-readable instructions which, when executed by a processor, cause the processor to perform the procedure described above.

[0008] Further applications of this disclosure will become apparent from the detailed description provided below. It should be understood that the detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the disclosure.

[0009] The features and advantages described above, and further features and advantages of the system and method disclosed herein, will become apparent from the detailed description, including the claims and exemplary embodiments, when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present revelation is more fully understood from the detailed description and the accompanying drawings; they show: Fig. 1 a schematic representation of a host vehicle containing a speed control system; Fig. 2 a schematic representation of a host vehicle attached to a trailer, wherein the host vehicle is traveling downhill and is spaced apart from the lead vehicle, and wherein the lead vehicle is also traveling downhill; Fig. 3 a flowchart of a speed control procedure for maintaining a following distance between a host vehicle and a lead vehicle while the host vehicle is traveling downhill; and Fig. 4. A flowchart of a procedure for determining a threshold for ending braking and a threshold for exiting tracking operation, which are used in the procedure of Fig. 3 can be used. DETAILED DESCRIPTION

[0011] Now, specific reference is made to some examples from the revelation, illustrated in accompanying drawings. Where possible, the same or similar reference symbols are used in the drawings and the description to refer to the same or similar sections or steps.

[0012] With reference to Fig. Figure 1 comprises a host vehicle 10, generally consisting of a body 12 and several wheels 14 coupled to the body 12. The host vehicle 10 can be an autonomous vehicle. In the illustrated embodiment, the host vehicle 10 is depicted as a sedan; however, it should be noted that other vehicles, including trucks, coupes, SUVs, recreational vehicles (RVs), etc., can also be used.

[0013] The host vehicle 10 further includes one or more sensors 24 which are coupled to the body 12. The sensors 24 detect observable conditions of the external environment and / or the internal environment of the host vehicle 10.As non-restrictive examples, the sensors 24 may include one or more cameras, one or more light detection and distance sensors (LIDAR sensors), one or more radars, one or more global positioning system transceivers (GPS transceivers), one or more tilt sensors, one or more inertial measurement units (IMUs), one or more accelerometers, one or more vehicle speed sensors, one or more wheel speed sensors, one or more yaw rate sensors, one or more gyroscopes, one or more proximity sensors, one or more cameras, one or more ultrasonic sensors, one or more thermal imaging sensors, and / or other sensors 24. Each sensor 24 is configured to generate a signal that reflects the detected observable conditions (e.g., sensor data) of the external environment and / or the internal environment of the host vehicle 10.

[0014] The host vehicle 10 contains a vehicle controller 34 communicating with the sensors 24. The vehicle controller 34 contains at least one vehicle processor 44 and a non-transient computer-readable vehicle memory device or a non-transient computer-readable vehicle memory medium 46. The vehicle processor 44 can be a custom-made or commercially available processor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processor among several processors associated with the vehicle controller 34, a semiconductor-based microprocessor (in the form of a microchip or a chipset), a macroprocessor, a combination thereof, or generally a device for executing instructions. The computer-readable vehicle memory device or the computer-readable vehicle memory medium 46 can, for example, be aThe vehicle contains volatile and non-volatile memory in read-only memory (ROM), read / write memory (RAM), and persistent memory (KAM). KAM is persistent or non-volatile memory that can be used to store various operating variables while the vehicle processor 44 is powered off. The computer-readable vehicle memory device or computer-readable vehicle memory medium 46 can be implemented using a number of memory devices such as PROMs (programmable read-only memory), EPROMs (electrical PROMs), EEPROMs (electrically erasable PROMs), flash memory, or other electrical, magnetic, optical, or combined memory devices capable of storing data, some of which represent executable instructions used by the vehicle controller 34 in controlling the host vehicle 10. The host vehicle 10's vehicle controller 34 can be programmed to execute the procedure 100 (. Fig. 3) and the procedure 200 ( Fig. 4) to be carried out as described in detail below.

[0015] The instructions can contain one or more separate programs, each comprising an ordered list of executable instructions for implementing logical functions. When executed by the vehicle processor 44, the instructions receive and process signals from sensors, perform logic, calculations, procedures, and / or algorithms to automatically control the components of the carrier vehicle 10, and generate control signals to automatically control the components of the carrier vehicle 10 based on the logic, calculations, procedures, and / or algorithms. Although in Fig. While a single vehicle controller 34 is shown in Figure 1, embodiments of the host vehicle 10 can include multiple vehicle controllers 34 that communicate via a suitable communication medium or a combination of communication media and that work together to process the sensor signals, perform logic, calculations, procedures and / or algorithms, and generate control signals to automatically control features of the host vehicle 10. The vehicle controller 34 is part of a system 21 for downhill tracking operation control using adaptive speed control across the entire speed range.

[0016] The host vehicle 10 includes a propulsion system 26 for driving the host vehicle 10 forward. The propulsion system 26 is coupled to one or more wheels 14 and can include an internal combustion engine 28 and / or an electric motor 30. The propulsion system 26 communicates with the vehicle controller 34. Accordingly, the vehicle controller 34 can receive information from the propulsion system 26. Furthermore, the vehicle controller 34 can send instructions to the propulsion system 26.

[0017] Additionally, the host vehicle 10 includes a braking system 32 for decelerating the host vehicle 10. The braking system 32 is coupled to one or more wheels 14 and includes one or more brakes 36. The braking system 32 communicates with the vehicle controller 34. Accordingly, the vehicle controller 34 can receive information from the braking system 32. Furthermore, the vehicle controller 34 can send instructions to the braking system 32.

[0018] If the host vehicle is 10, as in Fig. As shown in Figure 2, when traveling downhill, it is desirable to maintain a predetermined following distance 38 (e.g., three meters) from the lead vehicle 40. The lead vehicle 40 is located directly and immediately in front of the host vehicle 10, and thus no other vehicle is located between the host vehicle 10 and the lead vehicle 40. A trailer 42 may be attached to the host vehicle 10 while the host vehicle 10 is traveling downhill. In this case, the host vehicle 10 travels along a roadway 48, which has a road surface 50. The gradient of the roadway 48 is defined as the angle θ from the road surface 58 to a virtual horizontal line 52.

[0019] Fig. Figure 3 shows a method 100 for maintaining the specified following distance 38 between the host vehicle 10 and the lead vehicle 40 while the host vehicle 10 is traveling downhill. The method 100 begins in block 102. In block 102, the vehicle controller 34 determines whether the host vehicle 10 is traveling downhill. To do this, the vehicle controller 34 can receive road gradient data from the sensors 24 (e.g., one or more tilt sensors) and / or GPS data from the GPS transceivers. The vehicle controller 34 then uses the road gradient data to determine that the host vehicle 10 is traveling downhill. The road gradient data can include the road gradient (i.e., the angle θ from the road surface 58 to a virtual horizontal line 52) of the roadway 48.Furthermore, the vehicle controller 34 determines the axle torque instruction to maintain the specified following distance 38 between the host vehicle 10 and the lead vehicle 40 while the host vehicle 10 travels downhill along the roadway 48. As explained, the lead vehicle 40 is located directly in front of the host vehicle 10. The axle torque instruction is a function of the roadway gradient of the roadway 48. As explained above, the roadway gradient is defined as the angle θ from the roadway surface 58 to a virtual horizontal line 52. The axle torque instruction can be a braking instruction. During a braking instruction, the vehicle controller 34 instructs the braking system 32 to apply the brakes 36 to decelerate the host vehicle 10. The vehicle controller 34 can use the following equation to determine the axle torque instruction: AxCommand=K1*HDerr+K2*ΔHDerr−mg*sin(θ) where: m is the mass of the host vehicle 10 plus the mass of the trailer 42; K1 is a first calibration factor; K2 is a second calibration factor; g is the gravitational constant; V is the speed of the host vehicle; HT is the tracking operating time selected by the driver; HD is the specified following distance (V*HT) 38 from the host vehicle to the lead vehicle; L is the measured distance from the host vehicle to the lead vehicle; HD err The tracking operation error HD - L is; θ is the angle from the road surface 50 to the virtual horizontal line 52; and ΔHD err a first derivation of the tracking operational error 38 with respect to time.

[0020] Procedure 100 then continues with block 104. In block 104, the vehicle controller 34 determines whether one or more brakes 36 of the host vehicle's braking system 32 are actuated to provide the previously determined axle torque instruction to maintain the specified following distance 38 from the host vehicle 10 to the lead vehicle 40.

[0021] If one or more brakes 36 are not applied, procedure 100 continues with block 104. In block 104, the vehicle controller 34 sets the brake application flag to false. Procedure 100 then continues with block 106. In block 106, procedure 100 restarts. If one or more brakes 36 are applied, procedure 100 continues with block 108.

[0022] In block 108, the vehicle controller 34 determines the maximum axle torque instruction. The maximum axle torque instruction is the instruction for the maximum permissible braking with respect to acceleration and is a function of the road gradient. The maximum axle torque instruction can be determined using a lookup table. This lookup table can be developed by testing the host vehicle 10 and contains the road gradient and acceleration as inputs and the maximum axle torque instruction as output. Alternatively, the vehicle controller 34 can use the following equation to determine the maximum axle torque instruction: AxCommandMax=max(0,g*sin(θ)) where: AxCommandMax is the instruction for the maximum axle torque; g is the gravitational constant; and θ is the angle from the road surface 50 to the virtual horizontal line 52, and where θ is defined as a positive value when going downhill and as a negative value when going uphill, and g*sin(θ) is a positive value.

[0023] The procedure then continues with block 110. In block 110, the vehicle controller 34 determines a threshold value for ending braking, which in Fig. 4 is described in detail. The procedure then continues with block 112. In block 112, the vehicle controller 34 determines the threshold for exiting tracking mode, which in Fig. 4 is described in detail. The procedure then continues with block 114, as described in section 100.

[0024] In block 114, the controller 34 compares the maximum axle torque instruction with the braking termination threshold to determine if the axle torque instruction is greater than the braking termination threshold. If the axle torque instruction is greater than the braking termination threshold, procedure 100 continues to block 116. In block 116, the vehicle controller 34 compares the current following distance between the host vehicle 10 and the lead vehicle 40 with a tracking exit threshold to determine if the current following distance between the host vehicle 10 and the lead vehicle 40 is greater than the tracking exit threshold. If the current following distance between the host vehicle 10 and the lead vehicle 40 is greater than the tracking exit threshold, procedure 100 continues to block 104.In block 104, the vehicle controller 34 instructs the braking system 32 (and thus one or more brakes 36) of the host vehicle 10 to release the brakes in order to end braking. If the current following distance between the host vehicle 10 and the lead vehicle 40 is not greater than the threshold for exiting the following operation, procedure 100 continues with block 118. In block 118, the vehicle controller 34 limits the axle torque instruction to the instruction for maximum axle torque. Therefore, braking is not ended in block 118, but is limited to the instruction for maximum axle torque. After block 118, procedure 100 continues with block 106.

[0025] Fig. Figure 4 shows a flowchart of a procedure 200 for determining a threshold for ending braking and a threshold for exiting tracking mode, which are used in procedure 100 of Fig.3. Procedure 200 begins in block 202. Procedure 200 then continues to block 204. In block 204, the vehicle controller 34 determines an initial braking threshold. The initial braking threshold is determined using a lookup table developed by testing the host vehicle 10. The input to the lookup table is the road gradient of lane 48. Therefore, the initial braking threshold is a function of the road gradient. Procedure 200 then continues to block 206.

[0026] In block 206, the vehicle controller 34 determines a deceleration offset value. As explained below, the deceleration offset value is used when the speed of the lead vehicle 40 is greater than the speed of the host vehicle, and the lead vehicle 40 is therefore moving away from the host vehicle 10. The deceleration offset value is determined using a lookup table developed by testing the host vehicle 10. The input to this lookup table is the road gradient of lane 48. Therefore, the deceleration offset value is a function of the road gradient. Subsequently, procedure 300 proceeds to block 208.

[0027] In block 208, the vehicle controller 34 determines an initial threshold for exiting tracking mode. This initial threshold is determined using a lookup table developed by testing the host vehicle 10. The input to the lookup table is the road gradient of lane 48. Therefore, the initial threshold for exiting tracking mode is a function of the road gradient. Subsequently, procedure 200 proceeds to block 210.

[0028] In block 210, the vehicle controller 34 determines a tracking operating offset value. This value is determined using a lookup table developed by testing the host vehicle 10. The input to this lookup table is the road gradient of lane 48. Therefore, the tracking operating offset value is a function of the road gradient. Subsequently, procedure 300 proceeds to block 212.

[0029] In block 212, the vehicle controller 34 determines a speed delta. The speed delta is the difference between the speed of the lead vehicle 40 and the speed of the host vehicle 10. The vehicle controller 34 then compares the speed delta to a lead speed threshold to determine if the speed delta is greater than the lead speed threshold. If the speed delta is greater than the lead speed threshold, procedure 200 continues to block 214. If the speed delta is not greater than the lead speed threshold, procedure 200 continues to block 218.

[0030] In block 214, the vehicle controller 34, in response to determining that the speed delta is greater than the guide speed threshold, sets the braking termination threshold equal to the difference between the initial braking termination threshold and the deceleration offset value. The procedure 200 then continues with block 216.

[0031] In block 216, the vehicle controller 34, in response to determining that the speed delta is greater than the guide speed threshold, sets the threshold for exiting tracking mode to the difference between an initial threshold for exiting tracking mode and a tracking mode offset value. The procedure then continues with block 222. The procedure ends in block 222.

[0032] In block 218, the vehicle controller 34 sets the braking termination threshold to the same as the initial braking termination threshold. Procedure 200 then continues with block 220. In block 220, the vehicle controller 34 sets the initial exit threshold for tracking mode to the same as the initial exit threshold for tracking mode. Procedure 200 then continues with block 222. Procedure 200 ends in block 22w.

[0033] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the application text are descriptive rather than limiting, and it is understood that various modifications may be made without departing from the intent and scope of the disclosure. As previously described, features of different embodiments may be combined to form further embodiments of the system and method disclosed at present, which need not be expressly described or illustrated.While various embodiments may have been described as offering advantages or being preferred over other embodiments or implementations of the prior art with respect to one or more desired properties, those skilled in the art recognize that one or more features or properties may be subject to a trade-off in order to achieve desired overall system characteristics, which depend on the specific application and implementation. These features may include, but are not limited to, cost, strength, durability, life-cycle costs, marketability, appearance, packaging, size, usability, weight, manufacturability, ease of assembly, etc.Therefore, embodiments that are described as less desirable than other embodiments or implementations of the prior art with respect to one or more properties are not outside the scope of disclosure and may be desirable for certain applications.

[0034] The drawings are presented in simplified form and are not to scale. For the sake of simplification and clarity only, directional terms such as top, bottom, left, right, upwards, over, above, under, below, back, and front may be used in relation to the drawings. These and similar directional terms should not be interpreted as limiting the scope of disclosure in any way.

[0035] Here, embodiments of the present disclosure are described. However, it should be understood that the disclosed embodiments are merely examples and that further embodiments may take different and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of certain components. Therefore, specific structural and functional details disclosed here should not be interpreted as limiting, but merely as a representative basis for instructing a person skilled in the art in the use of the presently disclosed system and method in different ways.As relevant experts understand, various features illustrated and described with reference to any of the figures can be combined with features illustrated in one or more other figures to create embodiments not expressly illustrated or described. The combinations of illustrated features provide representative embodiments for typical applications. However, various combinations and modifications of the features in accordance with the instructions of this disclosure may be desirable for certain applications or implementations.

[0036] Here, embodiments of the present disclosure can be described with respect to functional and / or logical block components and various processing steps. It should be acknowledged that such block components can be implemented by several hardware, software, and / or firmware components configured to perform the specified functions. For example, an embodiment of the present disclosure may employ various integrated circuit components, such as memory elements, digital signal processing elements, logic elements, lookup tables, or the like, which can perform a variety of functions under the control of one or more microprocessors or other control devices.In addition, those skilled in the art understand that embodiments of the present disclosure can be practiced in connection with several systems and that the systems described herein are merely exemplary embodiments of the present disclosure.

[0037] For the sake of brevity, techniques relating to signal processing, data fusion, signaling, control, and other functional aspects of the systems (and the individual operating components of the systems) need not be described in detail here. Furthermore, the connecting lines shown in the various figures included herein are intended to represent examples of functional relationships and / or physical couplings between the various elements. It should be noted that alternative or additional functional relationships or physical connections may exist in an embodiment of this disclosure.

[0038] This description is for illustrative purposes only and is in no way intended to limit the disclosure, its application, or uses. The comprehensive teachings of the disclosure can be implemented in various forms. While this disclosure contains specific examples, the true scope of protection of the disclosure should therefore not be so limited as to reveal other modifications upon study of the drawings, the description, and the following claims. legend

[0039] In the drawing figures, N stands for no and Y for yes.

Claims

[1] Speed ​​control procedure, which includes: Determine that a host vehicle (10) is traveling downhill; Determining an instruction of axle torque to maintain a predetermined following distance (38) from the host vehicle (10) to a lead vehicle (40) while the host vehicle (10) travels downhill along a roadway (48), the lead vehicle (40) being immediately in front of the host vehicle (10), the instruction of axle torque being a function of a roadway gradient, the roadway (48) having a road surface (50) and the roadway gradient being an angle from the road surface (50) to a virtual horizontal line (52); Determine that a brake of the host vehicle (10) is applied to provide the previously determined instruction of axle torque; Comparing the axle torque instruction with a braking termination threshold to determine whether the axle torque instruction is greater than the braking termination threshold; Comparing, in response to determining that the axle torque instruction is greater than the threshold to stop braking, a current following distance between the host vehicle (10) and the lead vehicle (40) with a threshold to exit following operation, to determine whether the current following distance between the host vehicle (10) and the lead vehicle (40) is greater than the threshold to exit following operation; and Instructing the host vehicle (10) to release its brakes in response to the determination that the current following distance between the host vehicle (10) and the lead vehicle (40) is greater than the threshold for exiting pursuit operations to stop braking. [2] Speed ​​control method according to claim 1, further comprising: Determining the instruction of a maximum axle torque, wherein the instruction of the maximum axle torque is a function of the road gradient; and Restricting the axle torque instruction, in response to the determination that the axle torque instruction is not greater than the threshold for stopping braking, to the instruction of the maximum axle torque. [3] Speed ​​control method according to claim 2, further comprising: Determining the speed of the host vehicle (10); Determining the speed of the lead vessel (40); and Determining a speed delta, where the speed delta is a difference between the speed of the lead vehicle (40) and the speed of the host vehicle (10). [4] Speed ​​control method according to claim 3, further comprising: Comparing the velocity delta with a guide velocity threshold to determine if the velocity delta is greater than the guide velocity threshold. [5] Speed ​​control method according to claim 4, further comprising: Setting the threshold for stopping braking in response to determining that the speed delta is greater than the guide speed threshold, to a difference between an initial threshold for stopping braking and a value of the deceleration offset. [6] Speed ​​control method according to claim 5, further comprising: Setting the threshold for exiting tracking operations in response to determining that the velocity delta is greater than the guide velocity threshold to a difference between an initial threshold for exiting tracking operations and a tracking operation offset value. [7] Speed ​​control method according to claim 4, further comprising: Determine, in response to determining that the velocity delta is not greater than the guide velocity threshold, that the threshold for stopping braking is equal to an initial threshold for stopping braking. [8] Speed ​​control method according to claim 7, further comprising: Determine in response to determining that the speed delta is not greater than the initial threshold for exiting pursuit operation, that the threshold for exiting pursuit operation is equal to an initial threshold for exiting pursuit operation. [9] Speed ​​control method according to claim 1, wherein the instruction of the axle torque is a function of the predetermined following distance (38) from the host vehicle (10) to the lead vehicle (40). [10] Speed ​​control method according to claim 1, wherein the host vehicle (10) is attached to a trailer (42) and the instruction of the axle torque is determined using the following equation: AxCommand=K1*HDerr+K2*ΔHDerr−mg*sin(θ) where: m is the mass of the vehicle plus the mass of the trailer; K1 is a first calibration factor; K2 is a second calibration factor; g is the gravitational constant; V is the speed of the host vehicle; HT is a tracking operating time selected by the driver; HD is a predetermined following distance (V*HT) from the host vehicle to the lead vehicle; L is a measured distance from the host vehicle to the lead vehicle; HD err a tracking operational error HD - L is; θ is an angle from the road surface to the virtual horizontal line; and ΔHD err This is a first derivation of the tracking operational error with respect to time.

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