A method for regulating towing torque based on a commercial vehicle EBS system

Abstract

The application discloses a kind of based on commercial vehicle EBS system's tow torque regulation method, including the two-dimensional relationship table about vehicle speed, driving wheel slip rate and engine torque value is constructed;Real-time acquisition of the wheel speed of each wheel of vehicle, the maximum wheel speed method is used to calculate vehicle speed;According to vehicle speed and real-time driving wheel speed, determine real-time driving wheel slip rate;According to vehicle speed and real-time driving wheel slip rate, in two-dimensional relationship table corresponding engine torque value is inquired, or calculate engine torque value, engine torque value is output to EBS system;EBS system according to the engine torque value received, through the whole vehicle CAN bus TSC1_E message, to the engine with the set period frame sends request torque, to request torque and target torque NT between meet, complete EBS system's tow torque regulation. Through the way of table lookup, the complex input-output relationship is solved, and the operation efficiency of EBS system is improved.

Description

Technical Field

[0001] This invention belongs to the field of automotive safety control technology, specifically relating to a method for controlling drag torque based on the EBS system of commercial vehicles. Background Technology

[0002] The EBS system in commercial vehicles is a brake-by-wire system. This system employs a modular structure and can be integrated with dozens of functions such as deceleration control, brake force distribution, ABS, ESC, TCS, and DTC. Among these, drag torque control (DTC), a derivative function of the electronic stability control system, is primarily used to prevent drive wheel lock-up caused by transmission inertia or engine braking when commercial vehicles are driving on low-traction surfaces (such as ice, snow, or slippery surfaces). When the drive wheels are the front wheels, lock-up will cause the vehicle to lose steering ability; when the drive wheels are the rear wheels, lock-up will lead to the risk of sideslip or fishtailing. The drag torque control function typically monitors drive wheel speed and slip ratio. When it detects a tendency for the drive wheels to lock up, the system requests increased torque from the engine or electric motor to prevent prolonged wheel lock-up due to transmission system drag, thus ensuring vehicle stability. Currently, most commercial vehicle drag torque control methods based on EBS systems, both domestically and internationally, use the drive wheel slip ratio as input to perform PID control based on the drive wheel slip ratio difference in order to determine the torque increase value. However, due to the delay and low accuracy in calculating the drive wheel slip ratio, DTC control based solely on the drive wheel slip ratio is ineffective. Furthermore, the actual torque of the engine is not taken into account in actual control, resulting in jerking of the engine torque increase value, which urgently needs improvement. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a drag torque control method based on the EBS system of commercial vehicles, thereby solving the technical problem that the DTC control effect based solely on slip ratio in existing technologies is poor.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A method for controlling drag torque based on a commercial vehicle EBS system, characterized by the following steps: Step S1: Construct a two-dimensional relationship table between vehicle speed, drive wheel slip ratio, and engine torque boost, where vehicle speed and drive wheel slip ratio are inputs and engine torque boost is output. Step S2: Collect the wheel speed of each wheel of the vehicle in real time, and calculate the vehicle speed using the maximum wheel speed method; Step S3: Determine the real-time drive wheel slip ratio based on the vehicle speed determined in Step 2 and the collected real-time drive wheel speed; Step S4: Based on the vehicle speed determined in Step S2 and the real-time drive wheel slip ratio determined in Step S3, query the corresponding engine torque boost value in the two-dimensional relationship table constructed in Step S1: If both vehicle speed and real-time drive wheel slip ratio can be found in the two-dimensional relationship table, then the corresponding engine torque boost value is queried in the two-dimensional relationship table based on vehicle speed and real-time drive wheel slip ratio, and the queried engine torque boost value is output to the EBS system. If neither the vehicle speed nor the real-time drive wheel slip ratio is found in the two-dimensional relational table, or if the vehicle speed is not found in the two-dimensional relational table but the real-time drive wheel slip ratio is found in the two-dimensional relational table, or if the vehicle speed is found in the two-dimensional relational table but the real-time drive wheel slip ratio is not found in the two-dimensional relational table, then the bilinear interpolation equation is used to determine the engine torque increase value, and then the determined engine torque increase value is output to the EBS system. Step S5: Based on the received engine torque boost value, the EBS system sends a torque request to the engine frame by frame at a set period via the vehicle CAN bus TSC1_E message. To the requested torque With the target torque N T Between Complete the drag torque regulation of the EBS system; Among them, the requested torque Determined by the following formula:

[0006] In the formula: N To request torque; N R Increase engine torque; N A This represents the current actual torque output by the engine. t is the set period.

[0007] The present invention also has the following technical features: Specifically, in the two-dimensional relationship table, all vehicle speeds are stored in ascending order in the form of a one-dimensional table X_Axis, all drive wheel slip ratios are stored in ascending order in the form of a one-dimensional table Y_Axis, and the correspondence between vehicle speed and drive wheel slip ratio is stored in the form of a one-dimensional table Z_Table.

[0008] Furthermore, the real-time drive wheel slip ratio mentioned in step S4 is determined by the following formula: 100% In the formula: For real-time drive wheel slip ratio; Vehicle speed, in km / h; This represents the real-time drive wheel speed, expressed in km / h.

[0009] Furthermore, the bilinear interpolation equation described in step S4 is as follows:

[0010] In the formula: N R Increase engine torque; s For real-time drive wheel slip ratio; The speed is expressed in km / h.

[0011] Furthermore, the period set in step S6 is 100~200ms.

[0012] Furthermore, in step S5, ; In the formula: N To request torque; N R Increase engine torque; N T The target torque.

[0013] Compared with the prior art, the present invention has the following technical effects: This invention constructs a two-dimensional relationship table between vehicle speed, drive wheel slip ratio, and engine torque boost. Using vehicle speed and drive wheel slip ratio as inputs, it performs drag torque control. This approach resolves complex input-output relationships through table lookup, improving the operating efficiency of the EBS system. The interpolation calculation method simplifies the calculation process and ensures easily controllable accuracy. Simultaneously, the engine torque request is linearly boosted based on the engine's current actual torque, achieving smooth torque boost and reducing vehicle jerking caused by sudden torque changes. Detailed Implementation

[0014] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0015] The technical concept of this invention is to construct a two-dimensional relationship table between vehicle speed, real-time drive wheel slip ratio, and engine torque increase value, wherein vehicle speed and real-time drive wheel slip ratio are inputs, and engine torque increase value is output; determine the drive wheel slip ratio; calculate the engine torque increase value; after determining the torque increase value, perform linear torque increase based on the current actual torque of the engine to achieve smooth control and reduce engine jerking.

[0016] Example 1 Following the above technical solution, this embodiment provides a method for controlling drag torque based on a commercial vehicle EBS system, including the following steps: Step S1: Construct a two-dimensional relationship table between vehicle speed, drive wheel slip ratio, and engine torque boost, where vehicle speed and drive wheel slip ratio are inputs and engine torque boost is output. Specifically, in the two-dimensional relationship table, all vehicle speeds are stored in ascending order in the form of a one-dimensional table X_Axis, all drive wheel slip ratios are stored in ascending order in the form of a one-dimensional table Y_Axis, and the correspondence between vehicle speed and drive wheel slip ratio is stored in the form of a one-dimensional table Z_Table.

[0017] The two-dimensional relationship table constructed in this embodiment is as follows:

[0018] Table 1. Two-dimensional relationship between vehicle speed, drive wheel slip ratio, and engine torque increase. Step S2: Collect the wheel speed of each wheel of the vehicle in real time, and calculate the vehicle speed using the existing maximum wheel speed method. The collected wheel speed includes the real-time drive wheel speed.

[0019] Step S3: Determine the real-time drive wheel slip ratio based on the vehicle speed determined in Step 2 and the collected real-time drive wheel speed; Specifically, the real-time drive wheel slip ratio is determined by the following formula: 100% In the formula: For real-time drive wheel slip ratio; Vehicle speed, in km / h; This represents the real-time drive wheel speed, expressed in km / h.

[0020] Step S4: Based on the vehicle speed determined in Step S2 and the real-time drive wheel slip ratio determined in Step S3, query the corresponding engine torque boost value in the two-dimensional relationship table constructed in Step S1: If both vehicle speed and real-time drive wheel slip ratio are found in the two-dimensional relationship table, then the corresponding engine torque boost value is queried in the two-dimensional relationship table based on vehicle speed and real-time drive wheel slip ratio, and the queried engine torque boost value is output to the EBS system. If neither the vehicle speed nor the real-time drive wheel slip ratio is found in the two-dimensional relational table, or if the vehicle speed is not found in the two-dimensional relational table but the real-time drive wheel slip ratio is found in the two-dimensional relational table, or if the vehicle speed is found in the two-dimensional relational table but the real-time drive wheel slip ratio is not found in the two-dimensional relational table, then the bilinear interpolation equation is used to determine the engine torque increase value, and then the determined engine torque increase value is output to the EBS system. The bilinear interpolation equation is as follows:

[0021] In the formula: N R Increase engine torque; s For real-time drive wheel slip ratio; The speed is expressed in km / h.

[0022] Step S5: Based on the received engine torque boost value, the EBS system sends a torque request to the engine frame by frame at a set period via the vehicle CAN bus TSC1_E message. To the requested torque With the target torque N T Between Complete the drag torque regulation of the EBS system; Among them, the requested torque Determined by the following formula:

[0023] In the formula: N To request torque; N R Increase engine torque; N A This represents the current actual torque output by the engine. t is the set period.

[0024] In this embodiment, the set period is 100~200ms.

[0025] Application Example 1 In this application example, the vehicle speed calculated by the maximum wheel speed method at a certain moment is 60 km / h, and the real-time drive wheel speed collected is 42 km / h. Substituting these values ​​into the following formula: 100% In the formula: For real-time drive wheel slip ratio; Vehicle speed, in km / h; This represents the real-time drive wheel speed, expressed in km / h.

[0026] The calculated real-time drive wheel slip ratio s is 30%. At this point, the engine torque boost value can be directly obtained from the table. =13.

[0027] Based on the received engine torque boost value, the EBS system sends a torque request to the engine frame by frame via the vehicle CAN bus TSC1_E message at a set period (100ms). N To the requested torque With the target torque N T Between satisfy Complete the drag torque regulation of the EBS system; Among them, the requested torque N Determined by the following formula:

[0028] In the formula: N To request torque; N R Increase engine torque; N A This represents the current actual torque output by the engine. t is the set period.

[0029] Specifically, the target torque: .

[0030] Assuming at this time =13, =23, message sending period =0.1s, (When t=0.1, N=12.6; when t=0.2, N=15.2; ...). N specifically is [12.6, 15.2, 17.8, 20.4, 23]. Application Example 2 In this application example, at a certain moment, the maximum wheel speed method calculates the vehicle speed to be 50 km / h. The collected real-time drive wheel speed is 37.5 km / h, the vehicle speed V is 50 km / h, and the drive wheel slip ratio S is 25%. At this state, the engine torque boost value cannot be directly obtained from a table. The following formula needs to be substituted into the equation for calculation:

[0031] Calculated 10.28, rounded down to the nearest integer is =10: The EBS node monitors the actual torque of the engine in real time via the EEC1 message. The actual torque of the engine at the time of DTC triggering is recorded as follows: EBS communicates via the vehicle's CAN bus TSC1_E message at regular intervals. Sending torque request signals to the engine frame by frame : to the requested torque Achieve target torque value nearby( ).

[0032] =10, =20, message sending period =0.1s, (When t=0.1, N=12; when t=0.2, N=14...). At this time, the torque request signal N is sent frame by frame as [12, 14, 16, 18, 20].

[0033] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0034] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0035] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for controlling drag torque based on a commercial vehicle EBS system, characterized in that, Includes the following steps: Step S1: Construct a two-dimensional relationship table between vehicle speed, drive wheel slip ratio, and engine torque boost, where vehicle speed and drive wheel slip ratio are inputs and engine torque boost is output. Step S2: Collect the wheel speed of each wheel of the vehicle in real time, and calculate the vehicle speed using the maximum wheel speed method; Step S3: Determine the real-time drive wheel slip ratio based on the vehicle speed determined in Step 2 and the collected real-time drive wheel speed; Step S4: Based on the vehicle speed determined in Step S2 and the real-time drive wheel slip ratio determined in Step S3, query the corresponding engine torque boost value in the two-dimensional relationship table constructed in Step S1: If both vehicle speed and real-time drive wheel slip ratio can be found in the two-dimensional relationship table, then the corresponding engine torque boost value is queried in the two-dimensional relationship table based on vehicle speed and real-time drive wheel slip ratio, and the queried engine torque boost value is output to the EBS system. If neither the vehicle speed nor the real-time drive wheel slip ratio is found in the two-dimensional relational table, or if the vehicle speed is not found in the two-dimensional relational table but the real-time drive wheel slip ratio is found in the two-dimensional relational table, or if the vehicle speed is found in the two-dimensional relational table but the real-time drive wheel slip ratio is not found in the two-dimensional relational table, then the bilinear interpolation equation is used to determine the engine torque increase value, and then the determined engine torque increase value is output to the EBS system. Step S5: Based on the received engine torque boost value, the EBS system sends a torque request to the engine frame by frame at a set period via the vehicle CAN bus TSC1_E message. To the requested torque With the target torque N T Between satisfy Complete the drag torque regulation of the EBS system; Among them, the requested torque Determined by the following formula: In the formula: N To request torque; N R Increase engine torque; N A This represents the current actual torque output by the engine. t is the set period.

2. The drag torque control method based on the EBS system of commercial vehicles as described in claim 1, characterized in that, The construction of the two-dimensional relationship table in step S1 specifically includes: storing all vehicle speeds in ascending order in the form of a one-dimensional table X_Axis, storing all drive wheel slip ratios in ascending order in the form of a one-dimensional table Y_Axis, and storing the correspondence between vehicle speed and drive wheel slip ratio in the form of a one-dimensional table Z_Table.

3. The drag torque control method based on the EBS system of commercial vehicles as described in claim 1, characterized in that, The real-time drive wheel slip ratio mentioned in step S4 is determined by the following formula: 100% In the formula: For real-time drive wheel slip ratio; Vehicle speed, in km / h; This represents the real-time drive wheel speed, expressed in km / h.

4. The drag torque control method based on the EBS system of commercial vehicles as described in claim 3, characterized in that, The bilinear interpolation equation described in step S4 is as follows: In the formula: N R Increase engine torque; s For real-time drive wheel slip ratio; The speed is expressed in km / h.

5. The drag torque control method based on the EBS system of commercial vehicles as described in claim 1, characterized in that, The period set in step S6 is 100~200ms.

6. The drag torque control method based on the EBS system of commercial vehicles as described in claim 1, characterized in that, In step S5 ; In the formula: N To request torque; N R Increase engine torque; N T The target torque.

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