Main suspension braking coordination control method and system and traction trailer

Abstract

The invention relates to the technical field of main suspension braking coordination control and the technical field of anti-lock braking systems, in particular to a main suspension braking coordination control method and system and a traction trailer, and the main suspension braking coordination control method comprises the steps that the main vehicle speed, the trailer speed, the traction trailer speed, the main vehicle ABS state and the trailer ABS state are monitored in real time; controlling the speed of the main vehicle, the speed of the trailer, the speed of the traction trailer, the ABS state of the main vehicle and the ABS state of the trailer based on the braking coordination between the main vehicle and the trailer, and determining the braking coordination state of the main trailer; the main trailer braking coordination state is controlled based on the braking coordination between the main trailer and the trailer, main trailer braking coordination of the traction trailer is controlled, and the main trailer and the trailer are controlled through the braking coordination between the main trailer and the trailer.

Description

Technical Field

[0001] The present disclosure relates to the technical field of main brake coordination control and anti-lock braking system (ABS), and in particular to a main brake coordination control method, system and towing trailer. Background Art

[0002] With the growth of the drop-and-hook transport industry, the safety issues caused by the coordination of the main and trailer brakes of tractor trailers have become more and more prominent. In the current commercial vehicle market in my country, the main vehicle and trailer of tractor trailers are often produced by different companies, and the main vehicle and trailer are usually purchased separately during the purchase process. Users rarely pay attention to the matching of the main and trailer brake performance of tractor trailers, so it is easy to have problems such as poor coordination of the main and trailer brakes and folding of the main and trailer brakes.

[0003] In addition, the tractor trailer market has a serious problem of trailer modification, especially the use of trailer "brake king", which leads to nonlinear changes in the braking force of the trailer, making the coordination problem of the main trailer brake of the tractor trailer more prominent. At present, the industry tends to use regulatory constraints to improve the coordination status of the main trailer brake, but the effect is minimal. Summary of the invention

[0004] Based on the above technical problems, the present invention provides a main suspension brake coordination control method, system and tractor trailer, which are used to solve the problems of poor main suspension brake coordination and main suspension brake folding.

[0005] According to one aspect of the present disclosure, a main-trailer brake coordination control method is provided, which is characterized by comprising: real-time monitoring of the main vehicle speed, trailer speed, tractor trailer speed, main vehicle ABS status, and trailer ABS status; determining the main-trailer brake coordination status based on the main vehicle speed, trailer speed, tractor trailer speed, main vehicle ABS status, and trailer ABS status; and controlling the tractor trailer main-trailer brake coordination based on the main-trailer brake coordination status, wherein the tractor trailer includes the main vehicle and the trailer.

[0006] In addition, according to a main trailer brake coordination control method of one aspect of the present disclosure, the main trailer brake coordination state includes at least one or more of the trailer braking force being too small, the trailer braking force being too large, and the main trailer brake force being coordinated; based on the main vehicle speed, the trailer speed, the towing trailer speed, the main vehicle ABS state, and the trailer ABS state, the main trailer brake coordination state is determined, including: when the trailer ABS state is normal and the trailer speed can be obtained, obtaining the towing trailer target speed, determining the towing trailer speed and the towing trailer target speed When the speed of the towing trailer is greater than the target speed of the towing trailer, and the difference between the speed of the trailer and the speed of the main vehicle is greater than the first threshold value of the speed difference, it is determined that the braking force of the trailer is too small; or, when the speed of the towing trailer is not greater than the target speed of the towing trailer, and the difference between the speed of the main vehicle and the speed of the trailer is greater than the second threshold value of the speed difference, it is determined that the braking force of the trailer is too large; or, when the size relationship between the speed of the towing trailer and the target speed of the towing trailer does not meet the conditions for determining that the braking force of the trailer is too small or the braking force of the trailer is too large, it is determined that the braking force of the main trailer is coordinated.

[0007] In addition, according to a main trailer brake coordination control method according to one aspect of the present disclosure, the main trailer brake coordination state includes at least one or more of the trailer braking force being too small, the trailer braking force being too large, the main trailer brake force being coordinated, and the towing trailer brake force exceeding the road adhesion limit; based on the main vehicle speed, the trailer speed, the towing trailer speed, the main vehicle ABS state, and the trailer ABS state, the main trailer brake coordination state is determined, including: when the trailer ABS state is normal but the trailer speed cannot be obtained: when the trailer ABS state is not activated and the main vehicle ABS state is activated, it is determined that the trailer braking force is too small; or, when the trailer ABS state is activated and the main vehicle ABS state is not activated, it is determined that the trailer braking force is too large; or, when the trailer ABS state is not activated and the main vehicle ABS state is not activated, it is determined that the main trailer brake force is coordinated; or, when the trailer ABS state is activated and the main vehicle ABS state is activated, it is determined that the towing trailer brake force exceeds the road adhesion limit.

[0008] In addition, according to an aspect of the present disclosure, a main trailer brake coordination control method determines the main trailer brake coordination state based on the main vehicle speed, the trailer speed, the towing trailer speed, the main vehicle ABS state, and the trailer ABS state, and also includes: in the case of a trailer ABS state failure, obtaining the main vehicle deceleration, the towing trailer target speed and the towing trailer target deceleration, and judging the magnitude relationship between the towing trailer speed and the towing trailer target speed; when the towing trailer speed is not less than the towing trailer target speed, and the difference between the towing trailer target deceleration and the main vehicle deceleration is greater than a second deceleration difference threshold value, judging that the trailer braking force is too small; or, when the towing trailer speed is less than the towing trailer target speed, and the difference between the main vehicle deceleration and the towing trailer target deceleration is greater than a first deceleration difference threshold value, judging that the trailer braking force is too large; or, when the comparison result of the main vehicle deceleration difference and the towing vehicle target deceleration does not meet the conditions for judging that the trailer braking force is too small or judging that the trailer braking force is too large, judging that the main trailer braking force is coordinated.

[0009] In addition, according to an aspect of the main trailer brake coordination control method disclosed herein, the main trailer brake coordination state includes at least one or more of the trailer braking force being too small, the trailer braking force being too large, the main trailer brake force being coordinated, and the trailer brake force exceeding the road adhesion limit; based on the main trailer brake coordination state, the main trailer brake coordination of the tractor trailer is controlled, including: when the main trailer brake coordination state is that the trailer brake force is too small, the trailer is pressurized; when the main trailer brake coordination state is that the trailer brake force is too large, the vehicle trailer is first depressurized and then pressurized; when the main trailer brake coordination state is main trailer brake force coordination, there is no need to control the main trailer brake coordination, and the tractor trailer is braked according to the pedal travel; when the main trailer interactive coordination state is that the trailer brake force exceeds the road adhesion limit, the main vehicle and the trailer are depressurized.

[0010] In addition, according to an aspect of the present disclosure, the main trailer brake coordination control method further includes: determining whether the towing trailer has a braking intention based on the difference between the main vehicle speed and the trailer speed; if the braking intention is determined to be to release the brake, the trailer is braked to maintain pressure, and when the trailer returns to a natural state, it is decelerated together with the main vehicle; if the braking intention is determined to be to strengthen the brake, the trailer is pressurized separately;

[0011] If it is determined that the braking intention does not meet the judgment conditions for releasing the brake or strengthening the brake, the towing trailer is braked according to the pedal travel.

[0012] In addition, according to the main hanging brake coordination control method of one aspect of the present disclosure, the method for judging the braking intention includes: obtaining the initial pedal stroke; if the initial pedal stroke is not 0, obtaining k consecutive pedal strokes; when the k consecutive pedal strokes are not less than the initial pedal stroke, it is determined that the braking intention is to strengthen the braking; when the k consecutive pedal strokes are not greater than the initial pedal stroke, it is determined that the braking intention of the towing trailer is to release the braking; when the judgment conditions for strengthening the braking or releasing the braking are not met, it is determined that the braking intention is conventional braking.

[0013] In addition, according to an aspect of the main trailer brake coordination control method of the present disclosure, the target deceleration of the tractor trailer is obtained, including: obtaining the axle load, the air chamber brake torque gradient, the air chamber pressure, the road adhesion coefficient, and the tire rolling radius; when the ABS state of the tractor trailer is not activated, the target deceleration of the tractor trailer is determined based on the axle load, the air chamber brake torque gradient, the air chamber pressure and the tire rolling radius; when the ABS state of the tractor trailer is activated, the target deceleration of the tractor trailer is determined based on the road adhesion coefficient.

[0014] According to another aspect of the present disclosure, a main-trailer brake coordination control system is provided, including a brake control module, the brake control module is used to: monitor the main vehicle speed, trailer speed, traction trailer speed, main vehicle ABS status, trailer ABS status in real time; determine the main-trailer brake coordination status based on the main vehicle speed, trailer speed, traction trailer speed, main vehicle ABS status, trailer ABS status; based on the main-trailer brake coordination status, control the traction trailer main-trailer brake coordination, wherein the traction trailer includes the main vehicle and the trailer.

[0015] In addition, according to another aspect of the main trailer brake coordination control system of the present disclosure, the brake control module is also used to: control the electronically controlled trailer valve to control the braking force of the trailer; output a brake control signal to the main trailer brake coordination control valve to control the braking force of the trailer and the main vehicle.

[0016] In addition, according to another aspect of the main trailer brake coordination control system of the present disclosure, the brake control module is also used to: control the mechanical trailer valve through the trailer brake signal control valve and the two-way one-way valve to adjust the braking force of the trailer; output the brake control signal to the main trailer brake coordination control valve to control the braking force of the trailer and the main vehicle.

[0017] According to another aspect of the present disclosure, a tractor trailer is provided, which adopts the above-mentioned main trailer brake coordination control method to achieve brake coordination control between the main vehicle and the trailer.

[0018] The main-hook brake coordination control method, system and tractor trailer provided by the present invention can accurately determine the main-hook brake coordination state by monitoring the main vehicle speed, trailer speed, tractor trailer speed, main vehicle ABS state and trailer ABS state, and then dynamically adjust the braking force according to the main-hook brake coordination state, thereby ensuring the braking coordination of the tractor trailer and avoiding the problem of main-hook brake folding. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present disclosure or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 It is a graph showing the actual measured curve of the air chamber pressure of a tractor trailer using the trailer "Brake King" in the prior art provided according to an embodiment of the present disclosure.

[0021] Figure 2 It is a flowchart illustrating a method for coordinated control of main braking provided according to an embodiment of the present disclosure.

[0022] Figure 3 It is a flowchart further illustrating the main brake coordination control method provided according to an embodiment of the present disclosure.

[0023] Figure 4 It is a flowchart further illustrating the main brake coordination control method provided according to an embodiment of the present disclosure.

[0024] Figure 5 It is a flowchart of the target deceleration calculation of the tractor trailer.

[0025] Figure 6 Graph showing the measured curve of the air chamber braking torque gradient provided according to an embodiment of the present disclosure.

[0026] Figure 7 It is a flowchart further illustrating the main brake coordination control method provided according to an embodiment of the present disclosure.

[0027] Figure 8 is a flowchart illustrating a braking intention judgment provided according to an embodiment of the present disclosure.

[0028] Fig. 9 Detailed description is a functional block diagram of a main brake coordination control system provided according to an embodiment of the present disclosure.

[0029] Fig.10 2 is a diagram illustrating a main trailer brake coordination control device of an electronically controlled trailer valve system provided according to an embodiment of the present disclosure.

[0030] Fig.11 The diagram shows a main trailer brake coordination control device of a mechanical trailer valve system provided according to an embodiment of the present disclosure.

[0031] Fig.12 2 is a schematic diagram of a main brake coordination control valve provided according to an embodiment of the present disclosure.

[0032] Fig.13 2 is a schematic diagram of a trailer brake signal control valve according to an embodiment of the present disclosure.

[0033] Reference numerals:

[0034] Fig.10 Middle: 2-trailer valve; 3-main trailer brake coordination control valve; 4-trailer handshake red; 5-trailer handshake yellow; 6-trailer ABS signal; 7-brake control module; 3-port 3 of trailer valve; 11-port 11 of trailer valve; 21-port 21 of trailer valve, 22-port 22 of trailer valve; 41-port 41 of trailer valve, 42-port 42 of trailer valve; 43-port 43 of trailer valve.

[0035] Fig.11 Middle: 2-trailer valve; 3-main trailer brake coordination control valve; 4-trailer handshake red; 5-trailer handshake yellow; 6-trailer ABS signal; 7-brake control module; 8-trailer brake signal control valve; 9-two-way check valve.

[0036] Fig.12 Middle: 3-main brake coordination control valve; 1-port 1 of the main brake coordination control valve; 2-port 2 of the main brake coordination control valve;

[0037] Fig.13 Middle: 8-trailer brake signal control valve; 1-port 1 of the trailer brake signal control valve, 2-port 2 of the trailer brake signal control valve; 3-port 3 of the trailer brake signal control valve. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the technical solutions in the present disclosure will be clearly and completely described below in conjunction with the drawings in the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0039] like Figure 1 As shown in the prior art, the measured pressure curve of the air chamber of the tractor trailer under the trailer "Brake King" is Figure 1It shows the air chamber pressure of the main vehicle front axle air chamber, the main vehicle rear axle air chamber and the trailer air chamber under different pedal strokes. It can be seen from the figure that, except for the pedal idle stroke of about 1mm, the entire air chamber pressure curve has three stages. The pedal stroke in the first stage is 1mm to 4.2mm. In this stage, the trailer air chamber pressure is lower than the front and rear axle air chamber pressure. Due to the influence of the brake disc, brake drum and tire, the theoretical trailer air chamber pressure should be slightly larger than the main vehicle air chamber pressure. In this stage, the trailer will have insufficient braking force. The pedal stroke in the second stage is 4.2mm to 7.1mm. In this stage, due to the use of the trailer "brake king", the trailer air chamber pressure will increase sharply and be much higher than the main vehicle air chamber pressure. The change trend of the trailer braking force does not match that of the main vehicle braking force, which will make the overall braking of the traction trailer unbalanced. At the same time, if the trailer does not have ABS, there is a risk of the trailer locking and skidding. If the trailer has ABS, the trailer ABS will intervene in the adjustment too early, and the main vehicle's braking force has not been fully exerted. The braking force of the entire tractor trailer has not reached the limit state, which will affect the maximum braking force of the tractor trailer as a whole. The third stage pedal travel is 7.1mm to 10mm. In this stage, the air chamber pressure of the trailer has reached the maximum pressure, and the trailer braking force has been exerted to the limit. When the pedal travel is 7.1mm, the air chamber pressure of the main vehicle is only about 4bar, and the main vehicle still has 6bar of braking pressure that is not involved. The use of the "Brake King" causes a serious mismatch in the braking force of the main trailer, and the maximum braking performance of the tractor trailer cannot be exerted, affecting the driving safety of the tractor trailer.

[0040] Figure 2 It is a flowchart illustrating a method for coordinated control of main braking provided according to an embodiment of the present disclosure.

[0041] like Figure 2 As shown, the main brake coordination control method provided according to the embodiment of the present disclosure specifically includes the following steps.

[0042] In step S101, the main vehicle speed, the trailer speed, the towing trailer speed, the main vehicle ABS status, and the trailer ABS status are monitored in real time.

[0043] In an embodiment of the present disclosure, during the driving of the tractor trailer, the main vehicle speed, the trailer speed, the tractor trailer speed, the main vehicle ABS status and the trailer ABS status are monitored in real time.

[0044] In step S102, the main vehicle and trailer braking coordination state is determined based on the main vehicle speed, the trailer speed, the towing trailer speed, the main vehicle ABS state, and the trailer ABS state.

[0045] In the embodiments of the present disclosure, the main-trailer brake coordination state mainly refers to the state of mutual cooperation and interaction between the main vehicle and the trailer during the braking process, ensuring that the main vehicle and the trailer can maintain coordination during braking to achieve good braking effect and driving safety. Combined with the real-time monitored main vehicle speed, trailer speed, traction trailer speed, main vehicle ABS state, and trailer ABS state, the braking process of the main vehicle and the trailer is analyzed. On the basis of the braking analysis, the coordination of the main vehicle and the trailer during the braking process is further evaluated, thereby determining the main-trailer brake coordination state during the driving of the traction trailer.

[0046] In step S103, based on the main trailer brake coordination state, the main trailer brake coordination of the tractor trailer is controlled, wherein the tractor trailer includes a main vehicle and a trailer.

[0047] In an embodiment of the present disclosure, braking control is performed on the tractor trailer according to the determined main trailer braking coordination state to ensure braking coordination and driving safety between the main vehicle and the trailer.

[0048] In summary, according to the technical solution provided by the embodiment of the present disclosure, the present disclosure can accurately determine the coordination state of the main trailer brake by monitoring the main vehicle speed, the trailer speed, the towing trailer speed, the main vehicle ABS status, and the trailer ABS status, and then dynamically adjust the braking force according to the main trailer brake coordination state, thereby ensuring the braking coordination of the towing trailer and avoiding the problem of main trailer brake folding.

[0049] Furthermore, the main trailer braking coordination state includes at least one or more of the following: the trailer braking force is too small, the trailer braking force is too large, the main trailer braking force is coordinated, and the braking force exceeds the road adhesion limit.

[0050] Here, during the driving of the towing trailer, the main-trailer braking coordination state is usually one or more of the trailer braking force being too small, the trailer braking force being too large, and the main-trailer braking force being coordinated. The small trailer braking force means that during the braking process, the braking force applied by the trailer is relatively small compared to the main vehicle. The large trailer braking force means that during the braking process, the braking force applied by the trailer is relatively large compared to the main vehicle. The main-trailer braking force coordination means that the main vehicle and the trailer can cooperate and interact with each other during the braking process to maintain consistent braking force and response time. This state is an ideal braking coordination state. The braking force exceeding the road adhesion limit means that the braking force exceeds the maximum friction that the road surface can provide.

[0051] Further, based on the main vehicle speed, the trailer speed, the towing trailer speed, the main vehicle ABS state, and the trailer ABS state, the main and trailer braking coordination state is determined, including:

[0052] When the trailer ABS is in a normal state and the trailer speed can be obtained, the target speed of the towing trailer is obtained, and the magnitude relationship between the towing trailer speed and the target speed of the towing trailer is determined;

[0053] When the speed of the towing trailer is greater than the target speed of the towing trailer, and the difference between the speed of the trailer and the speed of the main vehicle is greater than the first threshold value of the speed difference, it is determined that the braking force of the trailer is too small; or,

[0054] When the speed of the towing trailer is not greater than the target speed of the towing trailer, and the difference between the speed of the main vehicle and the speed of the trailer is greater than the second threshold value of the speed difference, it is determined that the braking force of the trailer is too large; or,

[0055] When the magnitude relationship between the towing trailer speed and the towing trailer target speed does not satisfy the condition for determining that the trailer braking force is too small or the trailer braking force is too large, it is determined that the main trailer braking force is coordinated.

[0056] Specifically, based on the real-time monitored main vehicle speed, trailer speed, tractor trailer speed, main vehicle ABS status, and trailer ABS status, when the trailer ABS status can be determined and the trailer speed can be determined based on the trailer ABS signal, the tractor trailer target speed is obtained, and the main trailer brake coordination status is determined based on the real-time monitored tractor trailer speed (i.e., the current tractor trailer speed) and the tractor trailer target speed.

[0057] Here, if the speed of the tractor trailer is greater than the target tractor trailer speed, the speed difference is the difference between the trailer speed and the main vehicle speed. It is determined whether the speed difference is greater than the first speed difference threshold. If it is greater, it is determined that the braking force of the tractor trailer is too small at this time.

[0058] If the speed of the towing trailer is not greater than the target speed of the towing trailer, the speed difference is the difference between the speed of the main vehicle and the speed of the trailer. It is judged whether the speed difference is greater than the second threshold value of the speed difference. If it is greater, it is determined that the braking force of the towing trailer is too large at this time.

[0059] If the relationship between the speed of the towing trailer and the target speed of the towing trailer does not meet the above conditions for determining that the braking force of the trailer is too small or too large, it is determined that the towing trailer main trailer braking is coordinated at this time.

[0060] The first speed difference threshold is used to determine whether the trailer braking force is too small, while the second speed difference threshold is used to determine whether the trailer braking force is too large. These thresholds ensure that the tractor trailer system can maintain the best braking balance under different driving conditions. The thresholds can be dynamically adjusted to adapt to real-time changing driving conditions. This dynamic adjustment can be based on real-time sensor data, prediction models, or driver input, etc. This disclosure is not limited here.

[0061] In summary, according to the technical solution provided by the embodiment of the present disclosure, by real-time monitoring and analysis of the vehicle speed, ABS status and other parameters of the main vehicle and trailer, the main trailer brake coordination state can be more accurately judged, so as to take corresponding control measures to improve the braking safety of the entire tractor trailer system. Further, according to the accurate judgment of the main trailer brake coordination state, the braking force can be dynamically adjusted to avoid the problem of excessive braking distance or unstable braking caused by uncoordinated braking, thereby improving the braking efficiency. The method can adapt to different driving conditions, main trailer and trailer configurations, ensure effective braking coordination in various situations, and improve the adaptability and flexibility of the system. Through effective coordinated control, the brake system failure caused by brake mismatch, such as trailer brake folding or excessive braking distance, is reduced, and the service life of the brake system is extended. And the coordinated braking action reduces the impact and vibration of the vehicle during braking, providing the driver with a smoother and more comfortable driving experience. By reducing the repair and replacement costs caused by braking problems, the method helps to reduce the overall maintenance cost of the vehicle. Users can have more trust in the braking performance of the vehicle, and can remain safe even when the main vehicle and trailer are not well matched, thereby enhancing the user's confidence in the vehicle's braking system.

[0062] Further, based on the main vehicle speed, the trailer speed, the towing trailer speed, the main vehicle ABS state, and the trailer ABS state, the main and trailer braking coordination state is determined, including:

[0063] When the trailer ABS is in normal condition but the trailer speed cannot be obtained:

[0064] When the trailer ABS is not activated and the host vehicle ABS is activated, it is determined that the trailer braking force is too small; or,

[0065] When the trailer ABS is activated and the host vehicle ABS is inactive, it is determined that the trailer braking force is too large; or,

[0066] When the trailer ABS state is inactive and the host vehicle ABS state is inactive, it is determined that the host trailer braking force is coordinated; or,

[0067] When the trailer ABS is activated and the host vehicle ABS is activated, it is determined that the braking force of the towing trailer exceeds the road adhesion limit.

[0068] Specifically, based on the real-time monitoring of the main vehicle speed, trailer speed, traction trailer speed, main vehicle ABS status, and trailer ABS status. When the trailer ABS status is normal but the trailer speed cannot be obtained through the trailer ABS signal. Determine the activation status of the trailer ABS and the main vehicle ABS. If the trailer ABS is not activated and the main vehicle ABS is activated at the same time, the trailer braking force is too small at this time. If the trailer ABS is activated and the main vehicle ABS is not activated at the same time, the trailer braking force is too large at this time. If the trailer ABS is not activated and the main vehicle ABS is not activated at the same time, the main trailer braking force is coordinated at this time. If the trailer ABS is activated and the main vehicle ABS is activated at the same time, the traction trailer braking force exceeds the road adhesion limit at this time.

[0069] In summary, according to the technical solution provided by the embodiments of the present disclosure, by real-time monitoring of the speed and ABS status of the main vehicle and the trailer, when the ABS of the trailer is normal but the speed cannot be obtained, the braking force of the trailer and the coordination of the main trailer brake are judged according to the ABS activation status, thereby optimizing the braking strategy, improving braking safety, driving stability and driving experience, and reducing the risk of traffic accidents.

[0070] Since the trailer speed cannot be monitored, the main trailer brake coordination state cannot be accurately obtained when the ABS states of both the main vehicle and trailer are not activated. Therefore, it is necessary to use the traction trailer main trailer brake coordination control method for trailer ABS failure to monitor the main vehicle deceleration to perform main trailer brake coordination control.

[0071] Further, based on the main vehicle speed, the trailer speed, the towing trailer speed, the main vehicle ABS state, and the trailer ABS state, determining the main and trailer brake coordination state also includes:

[0072] In the case of a trailer ABS failure, the main vehicle deceleration, the towing trailer target speed and the towing trailer target deceleration are obtained to determine the magnitude relationship between the towing trailer speed and the towing trailer target speed;

[0073] When the speed of the towing trailer is not less than the target speed of the towing trailer, and the difference between the target deceleration of the towing trailer and the deceleration of the main vehicle is greater than the second threshold value of the deceleration difference, it is determined that the braking force of the trailer is too small; or,

[0074] When the speed of the towing trailer is less than the target speed of the towing trailer, and the difference between the main vehicle deceleration and the target deceleration of the towing trailer is greater than the first deceleration difference threshold, it is determined that the trailer braking force is too large; or,

[0075] When the comparison result between the main vehicle deceleration difference and the target deceleration of the tractor does not satisfy the conditions for determining that the trailer braking force is too small or determining that the trailer braking force is too large, it is determined that the main and trailer braking forces are coordinated.

[0076] Specifically, when the trailer ABS state fails, the main vehicle deceleration, the tractor trailer target speed and the tractor trailer target deceleration are obtained, the tractor trailer speed and the tractor trailer target speed are judged, and the current main trailer brake coordination state is judged.

[0077] If the speed of the tractor trailer is not less than the target tractor trailer speed, the deceleration difference is the difference between the target deceleration of the tractor trailer and the deceleration of the main vehicle. It is determined whether the deceleration difference is greater than the second threshold value of the deceleration difference. If so, it is determined that the braking force of the tractor trailer is too small.

[0078] If the speed of the tractor trailer is lower than the target tractor trailer speed, the deceleration difference is the difference between the main vehicle deceleration and the target deceleration of the tractor trailer. It is determined whether the deceleration difference is greater than the first deceleration difference threshold. If so, it is determined that the trailer braking force is too large.

[0079] If the comparison result of the main vehicle deceleration difference and the tractor target deceleration does not satisfy the conditions for determining that the trailer braking force is too small or the conditions for determining that the trailer braking force is too large, it is determined that the tractor trailer main trailer braking is coordinated at this time.

[0080] The first threshold value of the vehicle deceleration difference is used to determine whether the braking force of the trailer is too large, and the second threshold value of the deceleration difference is used to determine whether the braking force of the trailer is too small. These threshold values ​​ensure that the tractor trailer system can maintain the best braking balance under different driving conditions. The threshold values ​​can be dynamically adjusted to adapt to the real-time changing driving conditions. This dynamic adjustment can be based on real-time sensor data, prediction models or driver input, etc. This disclosure is not limited here.

[0081] In summary, according to the technical solution provided by the embodiment of the present disclosure, by comprehensively considering the speed of the main vehicle and the trailer, the ABS state and other factors, the braking coordination state of the main trailer can be more accurately judged, so that corresponding control measures can be taken to improve the braking safety of the entire tractor trailer system. Even if the trailer ABS fails or the trailer speed information cannot be obtained, the braking coordination can be judged and adjusted by monitoring the deceleration of the main vehicle and the target deceleration of the tractor trailer.

[0082] Furthermore, obtaining the target deceleration of the tractor trailer includes:

[0083] Obtain axle load, air chamber brake torque gradient, air chamber pressure, road adhesion coefficient, and tire rolling radius;

[0084] When the ABS state of the tractor trailer is not activated, the target deceleration of the tractor trailer is determined based on the axle load, the air chamber brake torque gradient, the air chamber pressure and the tire rolling radius;

[0085] When the ABS state of the tractor trailer is activated, the target deceleration of the tractor trailer is determined based on the road adhesion coefficient.

[0086] Specifically, load refers to the load on the vehicle axle, that is, the distribution of the vehicle weight on each axle. The size of the axle load directly affects the braking force required during braking to ensure that the vehicle can stop safely. The air chamber brake torque gradient refers to the relationship between the braking torque and air pressure that can be generated by the brake chamber under different air pressures. The brake torque gradient is usually used to describe the law of the braking force output by the brake chamber changing with the air pressure. The air chamber pressure refers to the air pressure in the brake chamber. In the pneumatic brake system, the level of the air chamber pressure directly determines the size of the braking force generated by the brake. The road adhesion coefficient reflects the friction characteristics between the tire and the road surface, which depends on the road material, road conditions (such as dry, wet, icy) and tire type. The tire rolling radius refers to the distance from the tire to the center of the tire contact point with the ground. By obtaining the axle load, air chamber brake torque gradient, air chamber pressure, road adhesion coefficient, and tire rolling radius, when the ABS state of the tractor trailer is not activated, the braking force is mainly determined by the braking force generated by the air chamber. In this case, the target deceleration of the tractor trailer can be calculated by the ratio of the air chamber output braking torque to the product of the vehicle load and the tire rolling radius. When the ABS state of the tractor trailer is activated, the vehicle braking force is the same as the maximum friction of the road surface. At this time, the target deceleration of the tractor trailer is the product of the road adhesion coefficient and the acceleration of gravity.

[0087] In summary, according to the technical solution provided by the embodiment of the present disclosure, through the above method, the target deceleration of the tractor trailer can be dynamically adjusted according to the activation state of the ABS and the parameters obtained in real time. This helps to achieve the best braking performance under different driving and road conditions and improve braking safety and efficiency. When the ABS is not activated, the braking force is controlled by the air chamber pressure and vehicle parameters to ensure that the braking capacity of the vehicle is not exceeded. When the ABS is activated, the braking force is adjusted according to the road conditions to prevent wheel locking and loss of traction.

[0088] Further, based on the main-hook brake coordination state of the tractor-trailer, the main-hook brake coordination of the tractor-trailer is controlled, including:

[0089] When the traction trailer main trailer brake coordination state is that the traction trailer trailer braking force is too small, the traction trailer trailer is pressurized;

[0090] When the braking coordination state of the tractor trailer is that the braking force of the tractor trailer is too large, the vehicle trailer is first depressurized and then pressurized;

[0091] When the main trailer brake coordination state of the tractor trailer is the main trailer brake force coordination, there is no need to control the main trailer brake coordination of the tractor trailer, and the tractor trailer brake is braked according to the pedal travel;

[0092] When the interactive coordination state of the tractor-trailer main vehicle and the tractor-trailer is that the trailer braking force exceeds the road adhesion limit, the tractor-trailer main vehicle and the tractor-trailer trailer are decompressed.

[0093] Specifically, when it is determined that the trailer braking force of the tractor trailer is too small, the trailer needs to be pressurized. This means that the trailer braking system needs to increase the braking force to match the braking effect of the main vehicle to ensure the braking coordination of the entire tractor trailer system. If it is determined that the trailer braking force is too large, the trailer needs to be decompressed first, and then the pressure needs to be appropriately increased (i.e., pressurized). This step is intended to adjust the braking force of the trailer so that it does not exceed the main vehicle, avoiding braking problems caused by excessive trailer braking force. When the main trailer braking force of the tractor trailer is in a coordinated state, there is no need to perform additional control on the braking coordination. In this case, the braking of the tractor trailer is mainly determined by the driver's pedal stroke, that is, the driver can directly adjust the braking force by controlling the pedal stroke. If the tractor trailer is in a state where the braking force exceeds the road adhesion limit, the main vehicle and the trailer need to be decompressed. This is to avoid wheel locking or loss of traction due to excessive braking force, and to ensure that the vehicle can maintain the best braking effect under various road conditions.

[0094] In summary, according to the technical solution provided by the embodiment of the present disclosure, the present disclosure can cope with different brake coordination states, aiming to ensure that the tractor trailer can maintain good braking performance and safety under various driving and braking conditions. And through real-time monitoring and dynamic adjustment, it can effectively solve the problems of poor coordination of main suspension brakes and main suspension brake folding, and improve the overall braking efficiency and safety of the tractor trailer.

[0095] Furthermore, when preventing the main brake from folding, the main brake coordination control method further includes:

[0096] Based on the difference between the speed of the main vehicle and the speed of the trailer, determining whether the towing trailer has a braking intention;

[0097] If it is determined that the braking intention is to release the brake, the trailer is braked to maintain pressure, and when the trailer returns to its natural state, it slows down together with the main vehicle;

[0098] If it is determined that the braking intention is to strengthen the brake, pressurize the trailer alone;

[0099] If it is determined that the braking intention does not meet the judgment conditions for releasing the brake or strengthening the brake, the towing trailer is braked according to the pedal travel.

[0100] Specifically, based on the real-time monitored main vehicle speed and trailer speed, the speed difference is defined as the difference between the trailer speed and the main vehicle speed. Determine whether the speed difference is greater than the third threshold value of the speed difference. If it is, it is determined that the current tractor trailer has a braking intention. If the tractor trailer's braking intention is to release the brakes, the current main trailer folds because the trailer's braking force decreases faster than the main vehicle. At this time, it is necessary to maintain the pressure of the trailer brakes and wait for the trailer to return to its natural state and slow down together with the main vehicle. If the tractor trailer's braking intention is to strengthen the brakes, the main trailer folds because the trailer's braking force is too small. At this time, the trailer needs to be pressurized separately. If the above judgment conditions are not met (that is, the braking intention does not meet the judgment conditions for releasing the brakes or strengthening the brakes), it is determined that the train has no risk of main trailer folding at this time, and the tractor trailer brake is based on the pedal travel.

[0101] The third threshold value of the vehicle speed difference is used to determine whether the tractor trailer has a braking intention. It can ensure that the tractor trailer can maintain the best braking balance under different driving conditions. The threshold value can be dynamically adjusted to adapt to the real-time changing driving conditions. This dynamic adjustment can be based on real-time sensor data, prediction models or driver input, etc. This disclosure is not limited here.

[0102] In summary, according to the technical solution provided by the embodiment of the present disclosure, by real-time monitoring of the speed of the main vehicle and the trailer, and judging the braking intention according to the speed difference, the braking behavior of the trailer can be more accurately controlled, thereby improving the braking coordination between the main and trailer. The operation of braking pressure maintenance or separate pressurization of the trailer can effectively reduce the risk of main trailer folding due to mismatched braking force and improve the driving safety of the train. According to different braking intentions, different braking measures can be taken to more flexibly respond to different braking requirements, thereby optimizing the braking performance of the train. By reducing the occurrence of abnormal situations such as main trailer folding, the driver's driving experience can be improved, making the driving process smoother and more comfortable.

[0103] The above braking intention can be judged in the following ways:

[0104] Get the initial pedal stroke;

[0105] If the initial pedal stroke is not 0, obtain k consecutive pedal strokes;

[0106] When the k consecutive pedal strokes are not less than the initial pedal stroke, it is determined that the braking intention is to strengthen braking;

[0107] When the k consecutive pedal strokes are not greater than the initial pedal stroke, it is determined that the braking intention of the towing trailer is to release the brake;

[0108] When the above two conditions (ie, the determination conditions for strengthening braking or releasing braking) are not satisfied, it is determined that the braking intention is normal braking.

[0109] Specifically, the initial pedal stroke is obtained. If the initial pedal stroke is not 0, k pedal strokes are obtained continuously. If the k consecutive pedal strokes are greater than or equal to the initial pedal stroke, the train braking intention is to strengthen the braking at this time; if the k consecutive pedal strokes are less than or equal to the initial stroke, the train braking intention is to release the braking at this time; if none of them are satisfied, the train braking intention is conventional braking at this time, which means that the driver is maintaining a relatively stable braking force or making fine adjustments. During the braking process of the tractor trailer, the driver's operation is given priority. That is, the driver's control of the tractor trailer braking has a higher priority than the control logic. If the initial pedal stroke is 0, there is no braking demand at this time.

[0110] In summary, according to the technical solution provided by the embodiment of the present disclosure, the present disclosure can accurately judge the braking intention of the tractor trailer by continuously monitoring the change of the pedal stroke, thereby improving the accuracy and response speed of braking, while ensuring the flexibility and safety of driving, and improving the overall driving experience. In addition, when the initial pedal stroke is 0, the method can identify that there is no braking demand, avoiding unnecessary braking operations, and improving driving comfort and fuel economy.

[0111] In order to better understand the technical solution of the present disclosure, refer to Figure 3-8 The main brake coordination control method provided according to the embodiment of the present disclosure is further illustrated.

[0112] like Figure 3 As shown, a flow chart of a coordinated control method for main suspension brake according to an embodiment of the present disclosure is further illustrated. The flow chart indicates that when the trailer ABS is normal, information such as the trailer ABS state and the trailer speed can be obtained through the trailer ABS signal 6. The coordinated control method for main suspension brake includes the following steps:

[0113] Step 10: The towing trailer is powered on for self-test to determine whether the trailer ABS status is normal. If normal, proceed to step 11; otherwise, proceed to step 34.

[0114] Step 11: When the tractor trailer starts braking, obtain the initial tractor trailer speed v at the beginning of the braking cycle e0 , go to step 12.

[0115] Step 12: Get the braking cycle period t and go to step 13.

[0116] Step 13: Obtain the target deceleration a of the tractor trailer for this braking cycle aim , target deceleration of the tractor trailer a aim The calculation method of Figure 5 Calculation flow chart of target deceleration of tractor trailer, proceed to step 14.

[0117] Step 14: Calculate the target vehicle speed v of the tractor trailer during this braking cycle aim , go to step 15.

[0118] The target speed v of the tractor trailer during this braking cycle aim The initial tractor trailer speed v of this braking cycle e0 and the target deceleration a of the tractor trailer aim The difference between the product of the cycle period t, that is:

[0119] v aim =v e0 -a aim t

[0120] Step 15: Get the current vehicle speed v m , go to step 16.

[0121] Step 16: Get the current tractor trailer speed v e , go to step 17.

[0122] Step 17: Determine whether the trailer ABS signal can obtain the trailer speed v t If the signal can be obtained, go to step 18, otherwise, go to step 27. Due to the chaos in the trailer market, there are a large number of trailers and main vehicle communication failures that cannot obtain the trailer speed, but the trailer ABS can be used normally and can receive the trailer ABS status.

[0123] Step 18: Determine the current tractor trailer speed v e Is it greater than the target speed v of the towing trailer? aim If yes, go to step 19, otherwise, go to step 23.

[0124] Step 19: Calculate the main trailer speed difference Δv and proceed to step 20.

[0125] Since the current tractor trailer speed v e Greater than the target speed v of the tractor trailer aim , and the target speed of the tractor trailer is v aim Mainly related to the target deceleration of the tractor trailer a aim The target deceleration of the tractor trailer is a aim It is related to the braking torque gradient of the main vehicle. Therefore, the speed v of the towing trailer can be determined. e Greater than the target speed v of the tractor trailer aim It may be caused by the small braking force of the trailer, the main vehicle speed v m Less than the trailer speed v t , the main trailer speed difference Δv is the trailer speed v t With the host vehicle speed v m The difference is:

[0126] Δv=v t -v m .

[0127] Step 20: Determine whether the main vehicle and trailer speed difference Δv is greater than the first vehicle speed difference threshold value v th1 If it is greater than, then go to step 21, otherwise, go to step 29. The first threshold value of the vehicle speed difference v th1 Can be obtained by calibration.

[0128] Step 21: Determine that the braking force of the trailer is too small at this time, and proceed to step 22.

[0129] Step 22: The trailer needs to be pressurized separately. Fig.11 The main brake coordination control device of the electric-controlled trailer valve system requires the main vehicle brake electronic control unit of the traction trailer brake control module 7 to send a signal to control the electric-controlled trailer valve to increase the pressure at port 22 alone to achieve the main brake coordination control. Fig.11 The main brake coordination control device of the mechanical trailer valve system requires the main brake coordination control unit in the towing trailer control module 7 to control the trailer brake signal control valve 8, and adjust the trailer brake signal control valve 8 from the exhaust state to the boost state to achieve the main brake coordination control.

[0130] Step 23: Calculate the main trailer speed difference Δv and proceed to step 24.

[0131] Since the current tractor trailer speed v e Not greater than the target speed v of the towing trailer aim , and the target speed of the tractor trailer is v aim Mainly related to the target deceleration of the tractor trailer a aim The target deceleration of the tractor trailer is a aim It is related to the braking torque gradient of the main vehicle. Therefore, the speed v of the towing trailer can be determined. e Not greater than the target speed v of the towing trailer aim It may be caused by the excessive braking force of the trailer, the main vehicle speed v m Greater than the trailer speed v t , the main trailer speed difference Δv is the main vehicle speed v m and trailer speed v t The difference is:

[0132] Δv=v m -v t .

[0133] Step 24: Determine the speed difference v between the main vehicle and the trailer t Is it greater than the second speed difference threshold v th2 If it is greater than, then go to step 25, otherwise, go to step 29. The second threshold value v of the vehicle speed differenceth2 Can be obtained by calibration.

[0134] Step 25: Determine that the braking force of the trailer is too large at this time, and proceed to step 26.

[0135] Step 26: At this time, the trailer needs to be decompressed and then maintained in pressure, that is, the main suspension brake coordination control unit in the traction trailer control module 7 controls the main suspension brake coordination control valve 3 to be in a decompression state, reduces the gas pressure of the trailer handshake valve (control) 5, and then maintains the pressure after reduction, and adjusts in a pulse form to realize the main suspension brake coordination control.

[0136] Step 27: Determine whether the trailer ABS status is activated. If not, proceed to step 28; otherwise, proceed to step 31.

[0137] Trailer ABS status is Mode ABS_t The value of the trailer ABS is indicated by the value of Mode. ABS_t 1, trailer ABS status is not activated assignment Mode ABS_t is 0.

[0138] Step 28: Determine whether the ABS status of the main vehicle is inactive. If not, proceed to step 29; otherwise, proceed to step 21.

[0139] The ABS status of the main vehicle is Mode ABS_m The value is used to indicate that the ABS state of the main vehicle is activated and the value Mode is assigned ABS_m If it is 1, the ABS state of the main vehicle is not activated, then the value Mode is assigned ABS_m is 0.

[0140] Step 29: Determine that the main braking force is coordinated at this time, and proceed to step 30.

[0141] Step 30: At this time, the main suspension braking force of the tractor trailer is matched and the main suspension braking is coordinated. Therefore, the braking force of the tractor trailer is based on the pedal travel and is mainly adjusted by the driver. There is no need to perform coordinated control of the main suspension braking.

[0142] Step 31: Determine whether the ABS status of the main vehicle is activated. If activated, proceed to step 32; otherwise, proceed to step 25.

[0143] Step 32: Determine that the overall braking force of the tractor trailer exceeds the limit (ie, the braking force of the tractor trailer exceeds the road adhesion limit), and proceed to step 33.

[0144] The conditions for determining whether the braking force of a tractor trailer exceeds the limit (the braking force of a tractor trailer exceeds the road adhesion limit) are as follows:

[0145] Mode ABS_t =1 and Mode ABS_m =1

[0146] Step 33: At this time, the braking force of the main vehicle and the trailer is greater than the extreme limit of the road surface, and the main trailer ABS is in an activated state. The main trailer braking force should be appropriately reduced to reach the maximum extreme limit of the road surface. At this time, the main trailer brake coordination control unit in the towing trailer control module 7 needs to control the main trailer brake coordination control valve 3 to decompress, reduce the gas pressure of the trailer handshake valve (control) 5, and then maintain the pressure after reduction, and adjust in the form of pulses to achieve the main trailer brake coordination control. The main vehicle needs to use the main vehicle brake control unit in the vehicle control module 7 to adjust the main vehicle brake.

[0147] Step 34: If the trailer ABS is faulty, proceed as follows: Figure 7 The flowchart of the main brake coordination control method provided by the embodiment of the present disclosure is shown, and the main brake coordination control is performed on the towing trailer with the trailer ABS failure. t When the signal is on, the main suspension brake coordination cannot be accurately judged, especially when the main vehicle ABS status and the trailer ABS status are not activated. At this time, it is necessary to cooperate with the main suspension brake coordination control method under the trailer ABS failure to realize the main suspension brake coordination control.

[0148] like Figure 4 As shown, a flow chart of the main suspension brake coordination control method provided according to an embodiment of the present disclosure is further illustrated, which considers that when the trailer ABS fails, the main suspension brake coordination control of the towing trailer is performed, and includes the following steps:

[0149] When the trailer ABS fails, the vehicle speed v e After that, the process should proceed to step 35, that is, after completing steps 11 to 16, proceed to step 35.

[0150] Step 35: Obtain the initial vehicle speed v of this braking cycle m0 , proceed to step 36.

[0151] Step 36: Calculate the vehicle deceleration a m , go to step 37.

[0152] Main vehicle deceleration a m The initial vehicle speed v of this cycle is m0 and the current vehicle speed v m The ratio of the difference between and the cycle period t is:

[0153]

[0154] Step 37: Determine the speed v of the towing trailer at this time e Is it less than the target speed v of the towing trailer? aimIf it is less than, the process goes to step 38 ; otherwise, the process goes to step 40 .

[0155] Step 38: Calculate the deceleration difference Δa and proceed to step 39.

[0156] At this time, the speed of the tractor trailer v e Less than the target speed v of the tractor trailer aim , it means that the braking force of the trailer may be too large, which will be reflected in the deceleration of the main vehicle a m The main vehicle deceleration is a m will be greater than the target deceleration a of the tractor trailer calculated by the braking torque gradient aim , define the deceleration difference Δa as the main vehicle deceleration a m and the target deceleration a of the tractor trailer aim The difference is:

[0157] Δa=a m -a aim

[0158] Step 39: Determine whether the deceleration difference Δa is greater than the first deceleration difference threshold a th1 If it is greater than, go to step 25, otherwise, go to step 29. The first threshold value a of the deceleration difference th1 Can be obtained by calibration.

[0159] Step 40: Calculate the deceleration difference Δa and proceed to step 41.

[0160] At this time, the speed of the tractor trailer v e Not less than the target speed v of the towing trailer aim , it means that the braking force of the trailer may be too small, which is reflected in the deceleration of the main vehicle a m The main vehicle decelerates a m will be less than the target deceleration a of the tractor trailer calculated by the braking torque gradient aim , define the deceleration difference Δa as the target deceleration a of the tractor trailer aim With the main vehicle deceleration a m The difference is:

[0161] Δa=a aim -a m

[0162] Step 41: Determine whether the deceleration difference Δa is greater than the deceleration difference second threshold a th2 If it is greater than, go to step 21, otherwise, go to step 29. The second threshold value a of the deceleration difference th2 Can be obtained by calibration.

[0163] Combination Figure 3 and Figure 4There are four main states of braking coordination of a tractor trailer, namely: the trailer braking force is too large, the trailer braking force is too small, the main trailer braking force is coordinated, and the main trailer braking force exceeds the limit.

[0164] The trailer braking force is too large. There are three judgment conditions in different trailer states: the main trailer speed difference Δv is greater than the second speed difference threshold v th2 , trailer ABS activated and host vehicle ABS not activated and deceleration difference Greater than the first deceleration difference threshold a th1 ,Right now:

[0165] v m -v t >v th2

[0166] or Mode ABS_t =1 and Mode ABS_m =0

[0167] or

[0168] a m -a aim >a th1

[0169] The trailer braking force is too small. There are three judgment conditions in different trailer states: the main trailer speed difference Δv is greater than the first speed difference threshold v th1 , the trailer ABS is not activated and the host vehicle ABS is activated and the deceleration difference Δa is greater than the deceleration difference second threshold a th2 ,Right now:

[0170] v t -v m >v th1

[0171] or

[0172] Mode ABS_t =0 and Mode ABS_m =1 or

[0173] a aim -a m >a th1

[0174] The main trailer braking force exceeds the limit state. When the trailer ABS is normal but the trailer speed v cannot be obtained t It can be determined in the case that the main vehicle ABS state is activated and the trailer ABS state is activated, that is:

[0175] Mode ABS_t =1 and Mode ABS_m =1

[0176] If the above judgment conditions are not met, it is considered that the braking force of the main trailer is coordinated, and the braking force is mainly based on the pedal travel.

[0177] like Figure 5 As shown in the figure, the target deceleration calculation flow chart of the tractor trailer, taking a certain axle as an example, includes the following steps:

[0178] Step 42: Obtain the axle load m, and proceed to step 43. The axle load can be obtained by calculating the output torque of the gearbox and the wheel speed and acceleration of each wheel during the acceleration process.

[0179] Step 43: Obtain the air chamber braking torque gradient T(P) of the shaft, and proceed to step 44. The air chamber torque gradient T(P) needs to be preset in the main vehicle brake electronic control unit in advance and self-corrected during the braking process.

[0180] Step 44: Obtain the air chamber pressure P and proceed to step 45.

[0181] Step 45: Obtain the road adhesion coefficient μ, and proceed to step 46. The road adhesion coefficient μ can be calculated by referring to the output torque of the gearbox, the wheel speed of each wheel, and the slip rate of each wheel during driving or acceleration.

[0182] Step 46: Get the tire rolling radius R roll , proceed to step 47.

[0183] Step 47: Determine whether ABS is not activated. If activated, proceed to step 48; otherwise, proceed to step 49.

[0184] Step 48: When ABS is not activated, the braking force of the tractor trailer is the same as the braking force generated by the air chamber. At this time, the target deceleration of the tractor trailer is a aim is the air chamber braking torque gradient T(P) and the load m and tire rolling radius R roll The ratio of the products, that is:

[0185]

[0186] Step 49: When ABS is activated, it can be assumed that the braking force of the tractor trailer is equal to the maximum friction force that can be generated by the ground. At this time, the target deceleration of the tractor trailer is a aim It is the product of the road adhesion coefficient μ and the gravitational acceleration g, that is: aim =μg

[0187] like Figure 6 As shown, the measured curve of the air chamber braking torque gradient is the measured 22.5-inch disc brake air chamber torque gradient curve. As the air pressure in the air chamber increases, the braking torque increases basically linearly.

[0188] like Figure 7As shown in the figure, the main suspension anti-folding control flow chart, the main vehicle folding is a typical problem often encountered by tractors, which is mainly caused by the main suspension brake mismatch. The main suspension folding control method includes the following steps:

[0189] Step 50: Get the vehicle speed v m , proceed to step 51.

[0190] Step 51: Get the trailer speed v t , proceed to step 52.

[0191] Step 52: Calculate the main trailer speed difference Δv, the main trailer speed difference Δv is the trailer speed v t With the host vehicle speed v m The process goes to step 53.

[0192] Step 53: Determine whether the speed difference Δv between the main vehicle and the trailer is greater than the third speed difference threshold value v th3 If it is greater than, proceed to step 56, otherwise, proceed to step 54. The third threshold value v th3 Can be obtained by calibration.

[0193] Step 54: Determine that there is no risk of main suspension folding at this time, and proceed to step 55.

[0194] Step 55: At this time, the braking force of the main suspension of the tractor trailer matches, there is no risk of the main suspension folding, and the braking force of the tractor trailer is based on the pedal travel.

[0195] Step 56: Determine whether the braking intention of the tractor trailer is to release the pedal braking intention mode Mode BST Is it 0?

[0196] If yes, go to step 57, otherwise, go to step 59.

[0197] Step 57: It is determined that there is a risk of main trailer folding when the brakes of the towing trailer are released, and the process goes to step 58.

[0198] Step 58: At this time, the tractor trailer is in the brake release state, and the brake signal of the tractor trailer is attenuating. The risk of main trailer folding exists because the braking force of the trailer is too small. Therefore, when the tractor trailer is depressurized, the main trailer brake coordination control valve 3 needs to enter the pressure holding mode and not depressurize along with the decompression signal of the tractor trailer. Since the tractor trailer is currently in the brake release state, the pressure at port 1 of the main trailer brake coordination control valve 3 is decreasing. When the main trailer brake coordination control valve 3 enters the pressure holding mode, it is not necessary to enter the decompression mode to achieve the brake reduction of the trailer. It can return to the natural state and be controlled by the brake air pressure of the tractor trailer.

[0199] Step 59: It is determined that there is a risk of main trailer folding when the towing trailer is braked more strongly, and the process goes to step 60.

[0200] Step 60: At this time, the towing trailer is in a reinforced braking state. When there is a risk of the main trailer folding, the braking force of the trailer is relatively small. Therefore, when the towing trailer is braked, the trailer needs to be pressurized separately. Figure 2 The main trailer brake coordination control device of the electronically controlled trailer valve system can directly control the trailer valve 3 by the traction trailer brake control module 7 to complete the separate pressurization of the trailer and realize the main trailer anti-folding control. Fig.11 The main trailer brake coordination control device of the mechanical trailer valve system requires the main trailer brake coordination control unit in the towing trailer control module 7 to control the trailer brake signal control valve 8, adjust the trailer brake signal control valve 8 from the exhaust state to the boost state, and control the main trailer anti-folding.

[0201] For a tractor trailer that cannot obtain the trailer speed, the risk of main trailer folding cannot be accurately determined. However, if the main trailer folds when the tractor trailer turns a large angle, it will have a serious impact. Therefore, for a tractor trailer that cannot obtain the trailer speed, the turning angle and lateral acceleration of the tractor trailer need to be considered, and the trailer braking force should be increased if necessary to prevent the main trailer from folding. This control logic is not described in detail.

[0202] like Figure 8 As shown, the braking intention judgment flow chart includes the following steps:

[0203] Step 61: Get Initial Pedal Travel x BST_0 , proceed to step 62.

[0204] Step 62: Determine the initial pedal travel x BST_0 Is it 0? If so, go to step 71; otherwise, go to step 63.

[0205] Step 63: Get k consecutive pedal strokes x BST_1 to x BST_k , proceed to step 64. The number k of continuous pedal strokes can be obtained by calibration.

[0206] Step 64: Determine whether the k consecutive pedal strokes are not less than the initial stroke x BST_0 If yes, go to step 65, otherwise, go to step 67.

[0207] Determine whether the k consecutive pedal strokes are not less than the initial pedal stroke x BST_0 The convertible judgment logic is: pedal travel x BST_1 to x BST_k Is the minimum value of greater than or equal to the initial pedal stroke x BST_0 ,Right now:

[0208] min{x BST_1 ...x BST_k}≥x BST_0

[0209] Step 65 : Determine that the braking intention of the towing trailer at this time is to strengthen braking, and proceed to step 66 .

[0210] Step 66: At this time, the pedal braking intention is to strengthen braking, and the pedal braking intention mode Mode is assigned BST is 1.

[0211] Step 67: Determine whether the k consecutive pedal strokes are not greater than the initial stroke x BST_0 If yes, go to step 68, otherwise, go to step 70.

[0212] Determine whether the k consecutive pedal strokes are not greater than the initial pedal stroke x BST_0 The convertible judgment logic is: pedal travel x BST_1 to x BST_k Is the maximum value of less than or equal to the initial pedal stroke x BST_0 ,Right now:

[0213] min{x BST_1 ...x BST_k}≤x BST_0

[0214] The number k of continuous pedal strokes can be obtained by calibration.

[0215] Step 68 : Determine that the braking intention of the towing trailer is to release the brake at this time, and proceed to step 69 .

[0216] Step 69: At this time, the pedal braking intention is to release the brake, and the pedal braking intention mode Mode is assigned BST is 0.

[0217] Step 70: It is determined that the braking intention of the tractor trailer is normal braking at this time, which means that the driver is maintaining a relatively stable braking force or making fine adjustments. That is, the driver is adjusting the braking of the tractor trailer at this time, and the braking control logic of the tractor trailer should not violate the braking intention of the driver. Therefore, it is determined that the braking intention is normal braking, and the process goes to step 61.

[0218] Step 71: Determine that there is no braking intention at this time, and go to step 61.

[0219] Fig. 9 Detailed description is a functional block diagram of a main brake coordination control system provided according to an embodiment of the present disclosure.

[0220] like Fig. 9 As shown, the main brake coordination control system 900 provided according to an embodiment of the present disclosure includes a brake control module 901, and the brake control module 901 is used to:

[0221] Real-time monitoring of the main vehicle speed, trailer speed, towing trailer speed, main vehicle ABS status, trailer ABS status;

[0222] Determine the main and trailer brake coordination status based on the main vehicle speed, trailer speed, towing trailer speed, main vehicle ABS status, and trailer ABS status;

[0223] Based on the main trailer brake coordination state, the main trailer brake coordination of the tractor trailer is controlled, wherein the tractor trailer includes a main vehicle and a trailer.

[0224] Furthermore, the brake control module is also used for:

[0225] Control the electronically controlled trailer valve to control the braking force of the trailer;

[0226] Output brake control signal to the main trailer brake coordination control valve to control the braking force of the trailer and the main vehicle.

[0227] Furthermore, the brake control module is also used for:

[0228] The mechanical trailer valve is controlled by the trailer brake signal control valve and the two-way check valve to adjust the braking force of the trailer;

[0229] Output brake control signal to the main trailer brake coordination control valve to control the braking force of the trailer and the main vehicle.

[0230] according to Fig. 9 The main suspension brake coordination control system shown in the present disclosure provides a main suspension brake coordination control device of an electronically controlled trailer valve system.

[0231] Fig.10 2 is a schematic diagram illustrating a coordinated control device for main trailer brake of an electronically controlled trailer valve system provided according to an embodiment of the present disclosure.

[0232] like Fig.10As shown, the main trailer brake coordination control device of the electric-controlled trailer valve system provided according to the embodiment of the present disclosure includes: a trailer valve 2 (i.e., an electric-controlled trailer valve), a main trailer brake coordination control valve 3, a trailer handshake red (gas source) 4, a trailer handshake yellow (control) 5, a trailer ABS signal 6 and a train control module 7 (i.e., the above-mentioned brake control module). The main trailer brake coordination control device is applied to the brake circuit, and the trailer valve 2 is an electric-controlled trailer valve, which can be controlled by the train control module 7. The trailer valve 2 is also controlled by the gas circuit. The 11th port of the trailer valve 2 is connected to the main vehicle air source, and the trailer is supplied with air through the trailer handshake red (gas source). The pressure of the air source and the trailer air circuit is generally 8.5 bar. The 21st port of the trailer valve 2 is connected to the trailer handshake red (gas source) 4, and the trailer handshake red (gas source) 4 is long-connected with the 11th port of the trailer valve and connected to the trailer. Port 22 of trailer valve 2 is connected to trailer handshake yellow (control) 5 through main trailer brake coordination control valve 3, and trailer handshake yellow (control) 5 is connected to the trailer to provide an air pressure control signal for the trailer brake air circuit, and control the braking force of the trailer by the size of the air pressure.

[0233] The main trailer brake coordination control valve 3 is a three-position three-way valve, corresponding to the natural state, pressure-maintaining state and pressure-reducing state, to achieve the adjustment of the trailer braking force. In the natural state, it is long-pass, which can achieve the functions of pass, pressure-maintaining and pressure-reducing. For details, please refer to Figure 4 .

[0234] Port 4 of trailer valve 2 is mainly connected to the control gas signal from the pedal and hand valve. Port 41 of trailer valve 2 is connected to the pedal gas signal, which is also the gas signal of the rear axle brake circuit; port 42 is connected to the pedal gas signal, which is also the gas signal of the front axle brake circuit; port 43 is connected to the hand valve gas signal, which is the gas signal sent by the trailer hand valve, and port 3 of trailer valve is mainly used for exhaust. Port 43 is normally ventilated during driving, and ports 41 and 42 have air pressure signals when there is a braking demand, and there is no air pressure during driving. The trailer ABS signal 6 comes from the trailer, which usually contains information such as whether the trailer ABS is faulty, the trailer ABS status, and the trailer speed. This information is given to the train brake control module 7 for calculation. The train brake control module 7 mainly includes a brake signal processing device, a main vehicle brake control unit, and a main trailer brake coordination control unit. The brake signal processing device mainly receives the brake signals of the main vehicle and the trailer, filters and analyzes them according to the priority, and forwards them to the main vehicle brake control unit and the main trailer brake coordination control unit. The main vehicle brake electronic control unit mainly controls the main vehicle front axle module, rear axle module and trailer valve, and can directly control the main vehicle braking force, and indirectly control the trailer braking force through the trailer valve. The main trailer brake coordination control unit mainly controls the main trailer brake coordination control valve 3 and the trailer brake signal control valve 8 in the main trailer brake coordination control device of the mechanical trailer valve system. The main trailer brake coordination control valve 3 and the trailer brake signal control valve 8 cooperate to realize the coordinated control of the main trailer brake of the train.

[0235] according to Fig. 9 The main suspension brake coordination control system shown in the present disclosure provides a main suspension brake coordination control device of an electronically controlled trailer valve system.

[0236] Fig.11 2 is a schematic diagram illustrating a coordinated control device for main trailer brakes of a mechanical trailer valve system provided according to an embodiment of the present disclosure.

[0237] like Fig.11 As shown, the main trailer brake coordination control device of the mechanical trailer valve system includes: trailer valve 2 (i.e., mechanical trailer valve), main trailer brake coordination control valve 3, trailer handshake red (air source) 4, trailer handshake yellow (control) 5, trailer ABS signal 6, train control module 7, trailer brake signal control valve 8 and two-way check valve 9. The device is basically the same as the main trailer brake coordination control device of the electronically controlled trailer valve system, the difference is that the trailer valve 2 in the device is a mechanical trailer valve, which can only be controlled by air signal and is not controlled by the main vehicle brake electronic control unit. Therefore, in the control circuit of the trailer valve 2, the control air pressure at port 41 can come from the pedal air signal and the trailer brake signal control valve 8 signal, and the three are connected through the two-way check valve 9. The outlet of the two-way check valve 9 is connected to port 41 of the trailer valve 2, and the air intake is respectively connected to the pedal air signal and the main vehicle air source through the trailer brake signal control valve 8. The two-way check valve 9 has the characteristic of high selection, and the air pressure of the two air inlets is the larger one. The trailer brake signal control valve 8 is a two-position three-way valve that can realize the amplification and exhaust of the brake signal. In the natural state, the solenoid valve is in the exhaust state. For specific implementation details, please refer to Fig.13 .

[0238] according to Fig. 9 The main brake coordination control system shown in the present disclosure provides a main brake coordination control valve schematic diagram.

[0239] Fig.12 2 is a schematic diagram of a main brake coordination control valve according to an embodiment of the present disclosure. Fig.12As shown, port 1 of the main hanging brake coordination control valve 3 is connected to port 22 of the trailer valve 2, port 2 is connected to the trailer handshake (control) 5, and port 3 is an exhaust port to the atmosphere. In the natural state, the main hanging brake coordination control valve 3 is in the lower position. At this time, port 1 of the main hanging brake coordination control valve 3 is connected to port 2, and the air pressure of port 1 is directly transmitted to port 2. The air pressure signal transmitted to the trailer circuit at the trailer handshake (control) 5 is not adjusted and is equal to the pressure at port 22 of the trailer valve. The middle position port 1 and port 2 of the main hanging brake coordination control valve 3 are both blocked. At this time, the pressure of port 1 cannot be transmitted to port 2, and the air pressure of port 2 remains at the state before entering the middle position. The air pressure signal transmitted to the trailer circuit at the trailer handshake (control) 5 is equal to the pressure of port 22 of the trailer valve before adjustment, and the main hanging brake coordination control valve 3 is in the pressure maintaining state. The upper port 1 of the main brake coordination control valve 3 is in a blocked state, and port 2 is connected to the exhaust port 3. At this time, the pressure at port 2 will decrease, and the air pressure signal transmitted to the trailer circuit at the trailer handshake yellow (control) 5 will decrease, and the main brake coordination control valve 3 is in a decompression state.

[0240] according to Fig. 9 The main trailer brake coordination control system shown in the present disclosure provides a schematic diagram of the trailer brake signal control valve.

[0241] Fig.13 2 is a schematic diagram of a trailer brake signal control valve according to an embodiment of the present disclosure.

[0242] like Fig.13 As shown, the schematic diagram of the trailer brake signal control valve, port 1 of the trailer brake signal control valve 8 is connected to the main vehicle air source, port 2 is connected to the two-way check valve 9, and port 3 is an exhaust port connected to the atmosphere. In the natural state, the trailer brake signal control valve 8 is located in the lower position, at which time port 1 of the trailer brake signal control valve 8 is in a blocked state, and port 2 is connected to the exhaust port 3. At this time, the pressure at port 2 is atmospheric pressure, and port 41 of the trailer valve 2 receives the pedal air signal, and the natural state is the exhaust state of the trailer brake signal control valve 8. The upper port 1 of the trailer brake signal control valve 8 is connected to port 2, at which time the pressure at port 2 is the air source pressure of 8.5 bar, and the pressure at port 2 increases. When the pedal air signal is less than the air source pressure, port 41 of the trailer valve 2 receives the pressure of the air source, and at this time, the trailer brake signal control valve 8 is in the pressurized state.

[0243] The above-mentioned trailer brake signal control valve is mainly used to connect the main vehicle air source at one end, the air source pressure is the maximum pressure of the trailer 8.5bar, and the other end is connected to the two-way one-way valve and then connected to the trailer valve 41 port to provide a brake signal for the trailer valve. The trailer brake signal control valve increases the trailer braking force through the on-off state.

[0244] On the other hand, the present disclosure further provides a tractor trailer, which is braked by using the above-mentioned main trailer brake coordination control method.

[0245] On the other hand, the present disclosure also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the main brake coordination control method provided by the above methods.

[0246] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0247] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0248] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A main brake coordination control method, characterized in that: include: Real-time monitoring of the main vehicle speed, trailer speed, towing trailer speed, main vehicle ABS status, trailer ABS status; Determining the main vehicle and trailer braking coordination state based on the main vehicle speed, trailer speed, towing trailer speed, main vehicle ABS state, and trailer ABS state; Based on the main trailer brake coordination state, the main trailer brake coordination of the tractor trailer is controlled, wherein the tractor trailer includes a main vehicle and a trailer.

2. The main brake coordination control method according to claim 1, characterized in that: The main trailer brake coordination state includes at least one or more of the following: the trailer braking force is too small, the trailer braking force is too large, and the main trailer brake force is coordinated; The determining of the main vehicle and trailer braking coordination state based on the main vehicle speed, trailer speed, towing trailer speed, main vehicle ABS state, and trailer ABS state includes: When the trailer ABS is in a normal state and the trailer speed can be obtained, obtaining the target speed of the towing trailer, and determining the magnitude relationship between the towing trailer speed and the target speed of the towing trailer; When the speed of the towing trailer is greater than the target speed of the towing trailer, and the difference between the speed of the trailer and the speed of the main vehicle is greater than a first threshold value of the speed difference, it is determined that the braking force of the trailer is too small; or, When the speed of the towing trailer is not greater than the target speed of the towing trailer, and the difference between the speed of the main vehicle and the speed of the trailer is greater than a second threshold value of the speed difference, it is determined that the braking force of the trailer is too large; or, When the magnitude relationship between the towing trailer speed and the towing trailer target speed does not satisfy the condition for determining that the trailer braking force is too small or the trailer braking force is too large, it is determined that the main trailer braking force is coordinated.

3. The main brake coordination control method according to claim 1, characterized in that: The main trailer braking coordination state includes at least one or more of the following: the trailer braking force is too small, the trailer braking force is too large, the main trailer braking force is coordinated, and the towing trailer braking force exceeds the road adhesion limit; The determining of the main vehicle and trailer braking coordination state based on the main vehicle speed, trailer speed, towing trailer speed, main vehicle ABS state, and trailer ABS state includes: When the trailer ABS is in normal state but the trailer speed cannot be obtained: When the trailer ABS is inactive and the host vehicle ABS is active, it is determined that the trailer braking force is too small; or, When the trailer ABS state is activated and the host vehicle ABS state is not activated, it is determined that the trailer braking force is too large; or, When the trailer ABS state is inactive and the host vehicle ABS state is inactive, it is determined that the host trailer braking force is coordinated; or, When the trailer ABS state is activated and the host vehicle ABS state is activated, it is determined that the braking force of the towing trailer exceeds the road adhesion limit.

4. The main brake coordination control method according to claim 3, characterized in that: The method of determining the main vehicle and trailer braking coordination state based on the main vehicle speed, trailer speed, towing trailer speed, main vehicle ABS state, and trailer ABS state further includes: In the case of a failure in the trailer ABS state, obtaining the main vehicle deceleration, the towing trailer target speed and the towing trailer target deceleration, and determining the magnitude relationship between the towing trailer speed and the towing trailer target speed; When the speed of the tractor trailer is not less than the target speed of the tractor trailer, and the difference between the target deceleration of the tractor trailer and the deceleration of the main vehicle is greater than the second threshold value of the deceleration difference, it is determined that the braking force of the trailer is too small; or, When the speed of the tractor trailer is less than the target speed of the tractor trailer, and the difference between the deceleration of the main vehicle and the target deceleration of the tractor trailer is greater than a first threshold value of the deceleration difference, it is determined that the braking force of the trailer is too large; or, When the comparison result of the main vehicle deceleration difference and the tractor target deceleration does not satisfy the condition of determining that the trailer braking force is too small or determining that the trailer braking force is too large, it is determined that the main and trailer braking forces are coordinated.

5. The main brake coordination control method according to claim 1, characterized in that: The main trailer braking coordination state includes at least one or more of the following: the trailer braking force is too small, the trailer braking force is too large, the main trailer braking force is coordinated, and the trailer braking force exceeds the road adhesion limit; The controlling the main suspension brake coordination of the tractor trailer based on the main suspension brake coordination state includes: When the main trailer brake coordination state is that the trailer braking force is too small, pressurizing the trailer; When the main trailer brake coordination state is that the trailer braking force is too large, the trailer is first depressurized and then pressurized; When the main suspension brake coordination state is the main suspension brake force coordination, there is no need to control the main suspension brake coordination, and the tractor trailer is braked according to the pedal travel; When the main vehicle and trailer interaction coordination state is that the trailer braking force exceeds the road adhesion limit, the main vehicle and the trailer are decompressed.

6. The main brake coordination control method according to claim 1, characterized in that: The method further comprises: Determining whether the towing trailer has a braking intention based on the difference between the speed of the main vehicle and the speed of the trailer; If it is determined that the braking intention is to release the brake, the trailer is braked to maintain pressure, and when the trailer returns to a natural state, it is decelerated together with the main vehicle; If it is determined that the braking intention is to strengthen braking, pressurize the trailer alone; If it is determined that the braking intention does not meet the determination condition for releasing the brake or strengthening the brake, the tractor trailer is braked according to the pedal travel.

7. The main brake coordination control method according to claim 6, characterized in that: The method for determining the braking intention includes: Get the initial pedal stroke; If the initial pedal stroke is not 0, obtain k consecutive pedal strokes; When the k consecutive pedal strokes are not less than the initial pedal stroke, it is determined that the braking intention is to strengthen braking; When the k consecutive pedal strokes are not greater than the initial pedal stroke, it is determined that the braking intention of the towing trailer is to release the brake; When the determination condition for strengthening braking or releasing braking is not satisfied, it is determined that the braking intention is normal braking.

8. The main brake coordination control method according to claim 4, characterized in that: The step of obtaining the target deceleration of the tractor trailer includes: Obtain axle load, air chamber brake torque gradient, air chamber pressure, road adhesion coefficient, and tire rolling radius; When the ABS state of the tractor trailer is not activated, determining the target deceleration of the tractor trailer based on the axle load, the air chamber brake torque gradient, the air chamber pressure and the tire rolling radius; When the ABS state of the tractor trailer is activated, the target deceleration of the tractor trailer is determined based on the road adhesion coefficient.

9. A main brake coordination control system, characterized in that: A brake control module is included, wherein the brake control module is used to: Real-time monitoring of the main vehicle speed, trailer speed, towing trailer speed, main vehicle ABS status, trailer ABS status; Determining the main vehicle and trailer braking coordination state based on the main vehicle speed, trailer speed, towing trailer speed, main vehicle ABS state, and trailer ABS state; Based on the main trailer brake coordination state, the main trailer brake coordination of the tractor trailer is controlled, wherein the tractor trailer includes a main vehicle and a trailer.

10. The main brake coordination control system according to claim 9, characterized in that: The brake control module is also used for: Controlling the electronically controlled trailer valve to control the braking force of the trailer; Output a brake control signal to the main trailer brake coordination control valve to control the braking force of the trailer and the main vehicle.

11. The main brake coordination control system according to claim 9, characterized in that: The brake control module is also used for: Controlling the mechanical trailer valve through the trailer brake signal control valve and the two-way check valve to adjust the braking force of the trailer; Output a brake control signal to the main trailer brake coordination control valve to control the braking force of the trailer and the main vehicle.

12. A tractor trailer, characterized in that: The tractor trailer is braked using the main trailer brake coordination control method according to any one of claims 1 to 8.

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