Inter-axle differential control method and device, electronic equipment and storage medium

Abstract

The invention relates to an inter-axle differential control method and device, electronic equipment and a storage medium, the method is applied to a vehicle with a first drive axle and a second drive axle, and the method comprises the steps that running parameters of the vehicle are obtained, and the running parameters comprise the vehicle speed, the steering angle, the accelerator opening degree and the output rotating speeds of the first drive axle and the second drive axle; when the absolute value of the steering angle is smaller than a preset angle threshold value, the accelerator opening degree is smaller than a preset opening degree threshold value, and the vehicle speed is smaller than a preset speed threshold value, it is judged that rotating speed control conditions are met, rotating speed control is conducted on the first drive axle and the second drive axle, and the output rotating speed of the first drive axle and the output rotating speed of the second drive axle are kept consistent; when it is judged that the rotating speed control condition is not met, the slip rate of the first drive axle and the slip rate of the second drive axle are determined according to the driving parameters, and when the slip rate of one drive axle is larger than a preset slip rate threshold value, torque output of the other drive axle is increased.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to an inter-axle differential control method, device, electronic equipment and storage medium. Background Art

[0002] Traditional commercial vehicles, such as tractors, usually adopt a centrally driven double rear axle structure. In this structure, a mechanical differential lock is provided between the driven middle axle and the driven rear axle. The two driving axles are forcibly locked through the mechanical structure, thereby achieving uniform power distribution and achieving the purpose of getting out of trouble. Although this design can effectively improve the vehicle's passing performance under complex road conditions, it has a complex mechanical structure, is heavy, and is not flexible enough to operate.

[0003] With the development of new energy vehicle technology, dual electric drive axle structures are gradually being used in the commercial vehicle field. In this structure, the middle axle and the rear axle are each equipped with an independent electric drive system, and the two drive axles no longer need to be connected by a traditional mechanical drive shaft, which greatly reduces the complexity of the transmission system and provides greater flexibility for vehicle layout.

[0004] However, due to the elimination of mechanical connection, the dual electric drive axle structure also brings new challenges under certain working conditions. For example, under complex road conditions such as slippery roads, icy roads, etc., due to the lack of forced synchronization of the mechanical differential lock, one or more drive wheels are prone to slip. When the drive wheel slips, a large amount of power is lost from the slipping wheel, which not only reduces the vehicle's traction performance, but may also cause the vehicle to fall into a dilemma where it cannot escape. In addition, the slippage of the drive wheel will also cause abnormal wear of the tires, increasing the cost of use.

[0005] Furthermore, during the energy recovery process, the dual electric drive axle structure also faces control difficulties: when one of the electric drive axles is at risk of locking, the existing technology often adopts a conservative strategy of overall exit from energy recovery, which not only reduces the energy recovery efficiency, but also affects driving stability.

[0006] Therefore, how to achieve coordinated control of the dual electric drive axles without relying on mechanical differential locks, improve the vehicle's passing performance under complex road conditions, and take into account energy recovery efficiency and driving stability is a technical problem that needs to be solved urgently. Summary of the invention

[0007] The invention discloses an inter-axle differential control method, device, electronic equipment and storage medium, aiming to solve the technical problems existing in the prior art.

[0008] The present invention adopts the following technical solutions:

[0009] In a first aspect, an embodiment of the present invention provides an inter-axle differential control method, which is applied to a vehicle having a first drive axle and a second drive axle, and includes the following steps:

[0010] Acquiring driving parameters of the vehicle, the driving parameters including vehicle speed, steering angle, throttle opening, and output speeds of the first drive axle and the second drive axle;

[0011] When the absolute value of the steering angle is less than a preset angle threshold, the throttle opening is less than a preset opening threshold, and the vehicle speed is less than a preset speed threshold, it is determined that the speed control condition is met, and the speed control is performed on the first drive axle and the second drive axle so that the output speeds of the first drive axle and the second drive axle are kept consistent;

[0012] When it is determined that the speed control condition is not met, the slip ratios of the first drive axle and the second drive axle are determined according to the driving parameters, and when the slip ratio of one drive axle is greater than a preset slip ratio threshold, the torque output of the other drive axle is increased.

[0013] In a possible implementation, the step of obtaining the driving parameters of the vehicle includes:

[0014] Acquiring tire rotation speeds of the front axle, the first drive axle, and the second drive axle;

[0015] obtaining the steering angle;

[0016] Acquiring an input rotation speed and an output rotation speed of the first drive axle and the second drive axle;

[0017] The vehicle speed is determined based on the tire speed, the steering angle, and the output speed.

[0018] In a possible implementation, the preset angle threshold is 45 degrees, the preset opening threshold is 75%, and the preset speed threshold is 15 km / h;

[0019] The speed control specifically includes:

[0020] detecting the output rotation speeds of the first drive axle and the second drive axle respectively;

[0021] According to the difference in the output speeds, the speeds of the first drive axle and the second drive axle are adjusted until the difference in the output speeds is zero.

[0022] In a possible implementation, the step of determining the slip rates of the first drive axle and the second drive axle according to the driving parameter, and increasing the torque output of the other drive axle when the slip rate of one drive axle is greater than a preset slip rate threshold, includes:

[0023] determining the slip ratios of the first drive axle and the second drive axle respectively based on the wheel speed of the front axle;

[0024] When the slip ratio of one of the drive axles is greater than the preset slip ratio threshold, the torque output of the drive axle is reduced through closed-loop control, while the torque output of the other drive axle is increased.

[0025] In a possible implementation, the method further includes:

[0026] Counting the number of fluctuations of the front axle speed and the first drive axle and the second drive axle within a unit time;

[0027] When the number of fluctuations is greater than a preset number threshold, the speed control is forcibly performed to keep the output speeds of the first drive axle and the second drive axle consistent;

[0028] The vehicle status is monitored, and the speed control is exited when the vehicle status returns to normal.

[0029] In a possible implementation, the method further includes:

[0030] Detect whether the driver has turned on the inter-wheel differential lock;

[0031] When it is detected that the driver turns on the inter-wheel differential lock, the inter-axle differential control is forcibly activated.

[0032] In a possible implementation, the method further includes:

[0033] Detect whether the driver turns off the driving anti-skid function;

[0034] When it is detected that the driver turns off the driving anti-skid function, the inter-axle differential control is forcibly turned off, wherein the priority of the forced turning off is higher than the forced activation.

[0035] In a second aspect, an embodiment of the present invention provides an inter-axle differential control device, which is applied to a vehicle having a first drive axle and a second drive axle, and includes:

[0036] A parameter acquisition module, used for acquiring driving parameters of the vehicle, wherein the driving parameters include vehicle speed, steering angle, throttle opening, and output rotation speeds of the first drive axle and the second drive axle;

[0037] a speed control module, configured to, when the absolute value of the steering angle is less than a preset angle threshold, the throttle opening is less than a preset opening threshold, and the vehicle speed is less than a preset speed threshold, determine that a speed control condition is satisfied, and perform the speed control on the first drive axle and the second drive axle so that the output speeds of the first drive axle and the second drive axle are kept consistent;

[0038] The slip control module is used to determine the slip rates of the first drive axle and the second drive axle according to the driving parameters when it is determined that the speed control condition is not met, and to increase the torque output of the other drive axle when the slip rate of one drive axle is greater than a preset slip rate threshold.

[0039] In a third aspect, an embodiment of the present invention provides an electronic device, including:

[0040] Processor; and

[0041] A memory arranged to store computer executable instructions, which when executed causes the processor to perform a method as described in any one of the above.

[0042] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, which stores one or more programs. When the one or more programs are executed by an electronic device including multiple application programs, the electronic device executes a method as described in any one of the above items.

[0043] One embodiment of the above invention has the following advantages or beneficial effects:

[0044] The present invention mainly provides an inter-axle differential control method, device, electronic device and storage medium. By acquiring vehicle driving parameters in real time and performing intelligent analysis, different control strategies are adopted under different working conditions, which effectively solves the risk of dual electric drive axles being unable to escape due to drive wheel slipping and vehicle loss of control on icy and slippery roads.

[0045] Specifically, when the vehicle is traveling in a straight line at a low speed, the present invention can judge parameters such as steering angle, throttle opening and vehicle speed, and adopt a speed control strategy to keep the output speed of the two drive axles consistent, thereby avoiding mechanical losses caused by differential speed; when the vehicle turns or encounters complex road conditions, torque is dynamically distributed based on the slip rate, which not only ensures the vehicle's handling stability, but also solves the problem of overall exit due to locking of one set of electric drive axles during energy recovery, thereby improving energy recovery efficiency.

[0046] Furthermore, the embodiments of the present invention allow the driver to directly intervene in the functions to enhance the adaptability of the control; at the same time, electronic limited slip control is implemented under high-speed four-wheel drive conditions, thereby improving the driving quality of the entire vehicle, which not only improves the response speed and accuracy of the inter-axle differential control, but also increases the driving stability, thereby ensuring the vehicle's passing performance and driving safety under various complex road conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0048] Figure 1 A flow chart of an inter-axle differential speed control method provided by an embodiment of the present invention;

[0049] Figure 2 A flow chart of an inter-axle differential speed control method provided by another embodiment of the present invention;

[0050] Figure 3 A partial flow chart of an inter-axle differential speed control method provided by an embodiment of the present invention;

[0051] Figure 4 A flow chart of an inter-axle differential speed control method provided by another embodiment of the present invention;

[0052] Figure 5 A flow chart of an inter-axle differential speed control method provided by another embodiment of the present invention;

[0053] Figure 6 A structural block diagram of an inter-axle differential control device provided by an embodiment of the present invention;

[0054] Figure 7 A structural block diagram of an inter-axle differential control device provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0056] In the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. It should be understood by those skilled in the art that in the following embodiments, "electric drive axle" is "drive axle".

[0057] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] In the prior art, when a tractor with dual electric drive axles faces low-adhesion roads such as ice, snow, and wet roads, the drive wheels are prone to slipping, which not only causes power loss and reduced traction performance, but also may put the vehicle in a difficult situation where it cannot escape, while also aggravating tire wear. In addition, during the energy recovery process, when a group of electric drive axles is at risk of locking, the prior art adopts a conservative control strategy of overall exit, which not only reduces the energy recovery efficiency, but also affects driving stability.

[0059] In order to solve the deficiencies in the prior art, an embodiment of the present invention provides an inter-axle differential control method, which is preferably applicable to a pure electric drive commercial vehicle equipped with two electric drive axles. Preferably, the commercial vehicle described in this embodiment can be an electric truck, an electric bus, an electric transport vehicle, an electric tractor, etc. In the electric drive commercial vehicle, the two electric drive axles are respectively arranged at the intermediate shaft and the rear axle of the vehicle. For the convenience of explanation, the electric drive axle of the intermediate shaft is defined as the first drive axle, and the electric drive axle of the rear axle is referred to as the second drive axle. Specifically, each electric drive axle includes components such as a motor, a transmission and a differential, which are used to provide driving force for the corresponding axle. The front axle of the vehicle is a steering axle, which does not provide driving force and is only used for steering function.

[0060] In one embodiment of the present invention, the output power of the first drive axle and the second drive axle can be the same, or they can be configured differently according to the needs of the whole vehicle, which is not specifically limited here; both electric drive axles can achieve precise control of speed and torque through their own independent motor controllers, and can work together through the whole vehicle controller to provide greater power output, and also provide more flexible adjustment space for inter-axle differential control.

[0061] like Figure 1 In one embodiment of the present invention, the inter-axle differential speed control method at least includes steps S110 to S130.

[0062] Step S110, obtaining driving parameters of the vehicle, the driving parameters including vehicle speed, steering angle, throttle opening, and output rotation speeds of the first drive axle and the second drive axle.

[0063] In one embodiment of the present invention, the driving parameters in step S110 come from different sensors and / or control units.

[0064] Specifically, the EBS (electronic braking system) wheel speed sensor collects the rotation speed of each tire of the front axle, the first drive axle and the second drive axle; the ESC (electronic stability control system) steering angle sensor collects the vehicle's steering angle and monitors the vehicle's driving status, which includes straight driving, left turn, right turn, U-turn, etc.; the input and output speed sensors of the first drive axle collect the actual output speed of the first drive axle, and the input and output speed sensors of the second drive axle collect the actual output speed of the second drive axle.

[0065] Specifically, EBS is an electronically controlled braking system that controls pneumatic brakes through electronic signals. In this embodiment, the wheel speed sensor in the EBS system is mainly used to collect the rotation speed of each wheel. The wheel speed sensor of the EBS is installed at each wheel to collect the instantaneous rotation speed of all wheels, including the left and right wheel speeds of the front axle, the left and right wheel speeds of the first drive axle, and the left and right wheel speeds of the second drive axle; ESC is a vehicle active safety control system used to prevent the vehicle from skidding or losing control when turning. In this embodiment, the steering angle sensor in the ESC system is mainly used to collect the steering angle of the steering wheel. Furthermore, the ESC system can determine the driving state of the vehicle based on the data of the steering angle sensor.

[0066] For the first drive axle and the second drive axle, each drive axle is equipped with an input speed sensor and an output speed sensor, wherein the input speed sensor is installed on the motor output shaft to collect the actual speed of the motor, and the output speed sensor is installed on the transmission output shaft to collect the actual speed of the transmission output shaft. After the speed of the transmission output shaft is converted through the differential transmission ratio, the actual output speed of the drive axle can be obtained.

[0067] In one embodiment of the present invention, the vehicle controller determines the real speed of the vehicle through comprehensive calculation based on three sets of data: tire speed, steering angle and output speed.

[0068] Specifically, firstly, based on the tire speed collected by the EBS wheel speed sensor and combined with the dynamic radius of the tire, the vehicle speed value corresponding to each wheel is calculated. Among them, since the front axle is a non-drive axle, its tire speed data is less affected by the driving force and has a good reference value.

[0069] Taking into account the difference in rotation speed between the inner and outer tires when the vehicle is turning, the tire rotation speed needs to be corrected according to the steering angle collected by the ESC steering angle sensor. Therefore, when the vehicle is in a turning state, the rotation speed of the inner tire is less than that of the outer tire. The correction coefficient can be calculated based on parameters such as the vehicle's wheelbase and track width.

[0070] The data collected by the output speed sensors of the first drive axle and the second drive axle are used as reference values, and the weighted average is performed with the above calculation results. The output speed of the drive axle can be converted into the corresponding vehicle speed value after the dynamic radius of the wheel. By fusing and calculating these three sets of data, a more accurate real vehicle speed can be obtained. When a set of data is abnormal, the system will automatically adjust the weight of each set of data to ensure the reliability of the speed calculation.

[0071] Step S120: When the absolute value of the steering angle is less than a preset angle threshold, the throttle opening is less than a preset opening threshold, and the vehicle speed is less than a preset speed threshold, it is determined that the speed control condition is met, and the speed of the first drive axle and the second drive axle is controlled to keep the output speeds of the first drive axle and the second drive axle consistent.

[0072] Through the above-mentioned speed control, tire slippage caused by the speed difference between the drive axles can be effectively prevented, thereby improving the vehicle's passing performance.

[0073] In one embodiment of the present invention, the preset angle threshold is 45°, the preset throttle opening threshold is 75%, and the preset speed threshold is 15 km / h.

[0074] Specifically, when making a judgment on speed control, the current steering angle is first detected, and its absolute value is compared with the preset 45° threshold value to ensure that the vehicle performs speed control only at a smaller steering angle, avoiding unnecessary speed matching when steering at a large angle; at the same time, since power output needs to be guaranteed under high throttle conditions, the throttle opening is detected to see if it is less than the preset threshold value of 75% to avoid speed control when the driver accelerates with high throttle; in addition, it is necessary to confirm whether the vehicle speed is lower than the preset threshold value of 15km / h. This judgment mainly takes into account that tire slip is more likely to occur under low-speed conditions, so it is more necessary to perform speed control at this time.

[0075] When the above three conditions are met at the same time, speed control is started: first, the output speeds of the first drive axle and the second drive axle are detected, and the speed difference between the two is calculated. Then, according to the difference in output speeds, the speeds of the first drive axle and the second drive axle are adjusted to gradually reduce the difference until the difference in output speeds is zero.

[0076] In one embodiment of the present invention, during the speed control process, by comparing the output speeds of the first drive axle and the second drive axle, the size and direction of the speed difference are first determined. For example, when the speed of the first drive axle is greater than the speed of the second drive axle, it is necessary to appropriately reduce the speed of the first drive axle, or increase the speed of the second drive axle.

[0077] In one embodiment of the present invention, when adjusting the speed, the speed difference between the two is not directly adjusted to zero, but it is preferably adjusted step by step in small steps. By adjusting the output torque of the motor, the drive axle with a higher speed gradually slows down, and the drive axle with a lower speed gradually speeds up, so as to avoid the impact of a sudden change in the speed of a certain electric drive axle on the vehicle.

[0078] During the adjustment process, the output speeds of the two drive axles are continuously monitored. After each adjustment, the speed difference is recalculated and the adjustment is continued according to the new difference until the difference is close to zero. The whole process adopts a closed-loop control strategy to dynamically adjust the control amount according to the changes in the actual speed difference.

[0079] In one embodiment of the present invention, in order to ensure the stability of the speed control, the step size limit can be adjusted to avoid a single adjustment range that is too large. This gradual adjustment method can ensure the control effect while avoiding power output fluctuations caused by drastic adjustments.

[0080] During the energy recovery process of the vehicle, through the above control, even if a certain drive axle tends to slip, timely speed control can be used to prevent the single drive axle from locking and avoid the entire energy recovery system from shutting down, thereby improving the energy recovery efficiency.

[0081] Step S130: When it is determined that the speed control condition is not met, the slip rates of the first drive axle and the second drive axle are determined according to the driving parameters, and when the slip rate of one of the drive axles is greater than a preset slip rate threshold, the torque output of the other drive axle is increased.

[0082] In one embodiment of the present invention, when the vehicle does not meet the speed control condition, it is necessary to monitor the slip ratio and adjust the torque.

[0083] Specifically, first obtain the reference vehicle speed. Since the front axle is a non-drive axle, its wheel speed is less affected by the driving force and can be used as the reference vehicle speed for calculating the slip rate. Then convert the actual output speeds of the first drive axle and the second drive axle into corresponding vehicle speeds, compare them with the front axle speed, and calculate the slip rates of the two drive axles respectively. Those skilled in the art should understand that the slip rate indicates the degree of difference between the linear speed of the drive wheel and the actual driving speed of the vehicle.

[0084] Furthermore, the slip rates of the two drive axles are monitored in real time. Once the slip rate of one of the drive axles is detected to exceed the preset threshold, it means that the drive axle has a large slip. At this time, the closed-loop control is started: for the drive axle that has slipped, its motor output torque is gradually reduced to reduce the slip degree. At the same time, in order to ensure the power output of the vehicle, the torque of the other drive axle is increased accordingly. The torque is adjusted in a progressive manner to avoid the impact caused by sudden changes. In this embodiment, the specific value of the preset slip rate threshold is no longer specifically limited, and those skilled in the art can make adaptive adjustments according to actual needs.

[0085] During the closed-loop process, changes in slip rate are continuously monitored and torque distribution is dynamically adjusted accordingly until the slip rate drops to a reasonable range, in order to suppress wheel slippage while ensuring vehicle dynamics.

[0086] In one embodiment of the present invention, in the process of closed-loop control of torque, various real-time data are continuously collected, including the front axle vehicle speed, the output speed of the two drive axles, the current torque output value, etc., and the real-time slip rate is calculated based on these data and used as feedback. Then, the target slip rate is set as the expected value, and compared with the actual slip rate to obtain the slip rate deviation. When adjusting the torque, closed-loop control is performed through the PID strategy. When a slipping drive axle appears, the controller will calculate the torque value that needs to be adjusted based on the slip rate deviation; for the slipping drive axle, its torque output is gradually reduced, and at the same time, in order to maintain the total driving force, the torque of the other drive axle is gradually increased. The amplitude of each adjustment is determined by the deviation size, and the larger the deviation, the larger the adjustment amplitude. Then continue this process, and continuously adjust the torque distribution of the two drive axles until the slip rate drops to within the target range.

[0087] Through the above-mentioned torque adjustment strategy, the vehicle can maintain good traction performance under complex road conditions, improving passability and safety.

[0088] like Figure 2 In one embodiment of the present invention, in step S130, the following steps are also included:

[0089] Step S131, counting the number of fluctuations of the front axle speed and the first drive axle and the second drive axle within a unit time.

[0090] Specifically, the system will compare the difference between the front axle speed and the two drive axle speeds within a fixed time window. When the difference exceeds the set threshold, it is recorded as a fluctuation. The number of such fluctuations is continuously monitored and accumulated. In this embodiment, the specific value of the time window should be able to reflect the situation of continuous fluctuations, but should not be too long to cause statistical delays. It is not specifically limited here, and those skilled in the art can make adaptive settings as needed.

[0091] Step S132: when the number of fluctuations is greater than a preset number threshold, the speed control is forcibly performed to keep the output speeds of the first drive axle and the second drive axle consistent.

[0092] Specifically, when the number of fluctuations counted exceeds the preset threshold, it indicates that the vehicle is experiencing complex or severe road conditions (such as slippery roads, uneven roads, etc.). At this time, the wheels are prone to slipping or jumping. Even if the conventional speed control conditions (such as steering angle, throttle opening, vehicle speed, etc.) are not met at present, the system will start the forced speed control mode. At this time, other constraints will be temporarily ignored, and priority will be given to ensuring the speed consistency of the two drive axles to prevent wheel slippage due to differences in drive axle speeds, which helps to maintain vehicle stability and improve passing performance.

[0093] Furthermore, the controller will collect the current output speeds of the two drive axles, calculate the speed difference, and then progressively adjust the outputs of their respective motors to gradually make the speeds of the two tend to be consistent, avoiding the impact of sudden changes.

[0094] Step S133, monitor the vehicle status, and exit the speed control when the vehicle status returns to normal.

[0095] Specifically, while executing forced speed control, the system will continue to monitor multiple parameters to determine the vehicle status, including wheel speed stability, output speed fluctuation of the drive axle, and change trend of the front axle speed. When these parameters remain within the normal range for a period of time, it means that the vehicle status has returned to normal. When the vehicle status is monitored to be stable for a period of time, the system will smoothly exit the forced speed control mode and return to the normal control mode.

[0096] In a specific implementation, the above-mentioned inter-axle differential control method is executed by a vehicle controller (VCU, Vehicle Control Unit). The vehicle controller communicates with various sensors, motor controllers and other control units through the on-board CAN bus, obtains and processes the vehicle's driving parameters in real time, and thus coordinates and controls the working states of the first drive axle and the second drive axle.

[0097] The vehicle controller is responsible for executing the entire process from step S110 to step S130, including obtaining driving parameters, determining control conditions, calculating slip ratios, and outputting corresponding control instructions. Specifically, the vehicle controller sends the calculated target speed or torque value to the motor controllers of the first drive axle and the second drive axle through the CAN bus, and the motor controllers perform specific execution adjustments.

[0098] like Figure 3 In one embodiment of the present invention, the process further includes steps S141 to S142.

[0099] Step S141: Detect whether the driver turns on the inter-wheel differential lock.

[0100] Specifically, the function of the inter-wheel differential lock is to lock the speed difference between the left and right wheels of the same drive axle so that they rotate synchronously. The system will monitor the status of the inter-wheel differential lock in real time and detect whether the driver has operated the differential lock switch through relevant sensors.

[0101] Step S142: When it is detected that the driver turns on the inter-wheel differential lock, the inter-axle differential control is forcibly activated.

[0102] Specifically, when the driver actively turns on the inter-wheel differential lock, it means that the current road conditions may be more complicated and require better passing performance. At this time, the inter-axle differential control function is automatically triggered to coordinate the speed relationship between the two drive axles. It should be noted that the inter-axle differential function that is triggered at this time refers to the execution of the above steps S110 to S130, rather than just executing step S120. That is, even if the inter-axle differential is forced to execute, when the speed control conditions are not met, the adjustment in step S130 will still be performed and the inter-wheel differential lock function will be exited, such as Figure 3 .

[0103] In one embodiment of the present invention, when the driver turns on the inter-wheel differential lock, the system will force the execution of the complete inter-axle differential control process, namely the above-mentioned steps S110 to S130. Specifically: first, it is determined whether the speed control condition is met (step S110); if the condition is met, the speed control is performed (step S120) to keep the output speeds of the two drive axles consistent; if the speed control condition is not met, the system will proceed to step S130 to calculate and monitor the slip rate of the two drive axles according to the driving parameters. When the slip rate exceeds the threshold, the system will respond by adjusting the torque distribution of the two drive axles instead of forcibly maintaining the speed consistency.

[0104] That is to say, even if the driver turns on the inter-wheel differential lock, the system still needs to flexibly adjust the control method according to the actual driving conditions. If necessary, it can exit the forced speed synchronization control and instead adopt torque adjustment based on the slip rate to ensure the vehicle's driving safety and passing performance.

[0105] like Figure 4 In one embodiment of the present invention, the method further includes steps S151 to S152.

[0106] Step S151: Detect whether the driver turns off the driving anti-skid function.

[0107] Step S152: when it is detected that the driver turns off the driving anti-skid function, the inter-axle differential control is forcibly turned off, wherein the priority of forced turning off is higher than that of forced activation.

[0108] Specifically, the system will continuously monitor the switch status of the drive anti-skid function. When it detects that the driver actively turns off the drive anti-skid function through the relevant switch, it usually indicates that the driver wants to fully control the vehicle, which may be to cope with special driving scenarios or perform professional driving operations. At this time, the system should immediately respond to the driver's operation and forcibly turn off the inter-axle differential control to avoid the system's automatic intervention affecting the driver's operation.

[0109] In one embodiment of the present invention, even when other conditions (such as opening the inter-wheel differential lock) require forced activation of the inter-axle differential control, the driver's instruction to turn off the drive anti-skid function still has a higher priority, that is, the instruction to turn off the drive anti-skid function will override all other instructions requiring the activation of the inter-axle differential control, so that the driver can obtain full control of the vehicle at this time.

[0110] like Figure 5 In one embodiment of the present invention, a method for controlling an inter-axle differential speed is also provided, comprising steps S210 to S290.

[0111] Step S210: monitor the rotation speed of each tire of the front axle, the first drive axle and the second drive axle through the EBS wheel speed sensor.

[0112] Step S220: Monitor the steering angle of the vehicle through the ESC steering angle sensor and determine the driving status, including straight driving, left turn, right turn, U-turn, etc.

[0113] Step S230: determine the actual output speed of the first drive axle through the input and output speed sensors of the gearbox of the first drive axle, and confirm the actual output speed of the second drive axle through the input and output speed sensors of the gearbox of the second drive axle.

[0114] Step S240: Calculate and obtain the final real vehicle speed based on the tire speed, steering angle and output speed.

[0115] Step S250: confirm the current driving force and the actual intended driving speed of the vehicle through the accelerator pedal opening.

[0116] Step S260: When |ESC steering angle signal| is less than 45°, the throttle opening is ≤75% and the vehicle speed is less than 15 km / h, the control mode of the first drive axle and the second drive axle is adjusted to speed control to keep the output speeds of the first drive axle and the second drive axle consistent, which is equivalent to forcibly synchronizing the two.

[0117] Step S270: For working conditions other than step S260, the slip rate of the first drive axle and the second drive axle is detected based on the front axle speed. When the slip rate of one of the drive axles is greater than the preset value, the torque of the other axle is increased through PID torque adjustment and distribution to reduce the burden of the slipping drive axle, and the number of slips is counted. When the front axle speed fluctuates greatly with the first drive axle and the second drive axle for many times within a unit time, the control mode of step S260 is forced to proceed, and the vehicle status is monitored at the same time. After returning to normal, the differential mode is exited.

[0118] Step S280: When the driver turns on the inter-wheel differential lock, the above steps S210 to S260 are forcibly executed.

[0119] Step S290: When the driver turns off the ASR anti-skid function, the above steps S210 to S260 can be forcibly prohibited, and the prohibition priority is higher than that of step S280.

[0120] The embodiment of the present invention provides an inter-axle differential control device 300, such as Figure 6 , applied to a vehicle having a first drive axle and a second drive axle, the inter-axle differential control device 300 at least includes a parameter acquisition module 310, a speed control module 320, and a slip control module 330.

[0121] In one embodiment of the present invention, the parameter acquisition module 310 is used to acquire the driving parameters of the vehicle, wherein the driving parameters include vehicle speed, steering angle, throttle opening, and output rotation speeds of the first drive axle and the second drive axle.

[0122] In one embodiment of the present invention, the speed control module 320 is used to determine that the speed control condition is met when the absolute value of the steering angle is less than a preset angle threshold, the throttle opening is less than a preset opening threshold, and the vehicle speed is less than a preset speed threshold, and to perform the speed control on the first drive axle and the second drive axle so that the output speeds of the first drive axle and the second drive axle remain consistent.

[0123] In one embodiment of the present invention, the slip control module 330 is used to determine the slip rates of the first drive axle and the second drive axle according to the driving parameters when it is determined that the speed control condition is not met, and to increase the torque output of the other drive axle when the slip rate of one of the drive axles is greater than a preset slip rate threshold.

[0124] In one embodiment of the present invention, the slip control module 330 is also used to count the number of fluctuations between the front axle vehicle speed and the first drive axle and the second drive axle within a unit time. When the number of fluctuations is greater than a preset threshold, the speed control is enforced to keep the output speeds of the first drive axle and the second drive axle consistent.

[0125] like Figure 7 In one embodiment of the present invention, the inter-axle differential control device 300 further includes a differential lock detection module 340 and an anti-skid control module 350 .

[0126] In one embodiment of the present invention, the differential lock detection module 340 is used to detect whether the driver turns on the inter-wheel differential lock; when it is detected that the driver turns on the inter-wheel differential lock, the inter-axle differential control is forcibly activated.

[0127] In one embodiment of the present invention, the anti-skid control module 350 is used to detect whether the driver turns off the driving anti-skid function; when it is detected that the driver turns off the driving anti-skid function, the inter-axle differential control is forcibly turned off, wherein the forced closing has a higher priority than the forced activation.

[0128] It should be noted that the inter-axle differential control device 300 provided in the above embodiment and the embodiment of the inter-axle differential control method belong to the same concept, and the specific implementation process thereof is detailed in the embodiment of the control method, which will not be described one by one here.

[0129] In one embodiment of the present invention, a vehicle is also provided, which is equipped with the above-mentioned inter-axle differential control method. Preferably, the vehicle in this embodiment is a purely electrically driven commercial vehicle, such as an electric truck, an electric bus, an electric transport vehicle, an electric tractor, etc.

[0130] An embodiment of the present invention further provides an electronic device, which includes a memory and a processor, wherein a computer program executed by the processor is stored in the memory, and when the computer program is executed by the processor, the processor executes the inter-axle differential control method described above. Various applications and various data, such as various data used and / or generated by the application, may also be stored in the memory. The processor may be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other forms of processing units having data processing capabilities and / or instruction execution capabilities.

[0131] The embodiment of the present invention further provides a computer-readable storage medium, on which a computer program executed by a processor is stored. When the computer program is executed by the processor, the processor executes the inter-axle differential control method as described above. Exemplarily, the computer storage medium may include a memory card of a smart phone, a storage component of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disk read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. The computer-readable storage medium may be any combination of one or more computer-readable storage media.

[0132] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0133] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0134] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0135] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0136] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for controlling an inter-axle differential speed, characterized in that: The method is applied to a vehicle having a first drive axle and a second drive axle, and comprises the steps of: Acquiring driving parameters of the vehicle, wherein the driving parameters include vehicle speed, steering angle, throttle opening, and output speeds of the first drive axle and the second drive axle; When the absolute value of the steering angle is less than a preset angle threshold, the throttle opening is less than a preset opening threshold, and the vehicle speed is less than a preset speed threshold, it is determined that the speed control condition is met, and the speed control is performed on the first drive axle and the second drive axle so that the output speeds of the first drive axle and the second drive axle are kept consistent; When it is determined that the speed control condition is not met, the slip ratios of the first drive axle and the second drive axle are determined according to the driving parameters, and when the slip ratio of one drive axle is greater than a preset slip ratio threshold, the torque output of the other drive axle is increased.

2. The inter-axle differential speed control method according to claim 1, characterized in that: The step of obtaining the driving parameters of the vehicle includes: Acquiring tire rotation speeds of the front axle, the first drive axle, and the second drive axle; obtaining the steering angle; Acquiring an input rotation speed and an output rotation speed of the first drive axle and the second drive axle; The vehicle speed is determined based on the tire speed, the steering angle, and the output speed.

3. The inter-axle differential speed control method according to claim 2, characterized in that: The preset angle threshold is 45 degrees, the preset opening threshold is 75%, and the preset speed threshold is 15 km / h; The speed control specifically includes: detecting the output rotation speeds of the first drive axle and the second drive axle respectively; According to the difference in the output speeds, the speeds of the first drive axle and the second drive axle are adjusted until the difference in the output speeds is zero.

4. The inter-axle differential speed control method according to claim 1, characterized in that: The step of determining the slip ratios of the first drive axle and the second drive axle according to the driving parameters, and increasing the torque output of the other drive axle when the slip ratio of one drive axle is greater than a preset slip ratio threshold, comprises: determining the slip ratios of the first drive axle and the second drive axle respectively based on the wheel speed of the front axle; When the slip ratio of one of the drive axles is greater than the preset slip ratio threshold, the torque output of the drive axle is reduced through closed-loop control, while the torque output of the other drive axle is increased.

5. The inter-axle differential speed control method according to claim 4, characterized in that: Also includes: Counting the number of fluctuations of the front axle speed and the first drive axle and the second drive axle within a unit time; When the number of fluctuations is greater than a preset number threshold, the speed control is forcibly performed to keep the output speeds of the first drive axle and the second drive axle consistent; The vehicle status is monitored, and the speed control is exited when the vehicle status returns to normal.

6. The inter-axle differential speed control method according to claim 1, characterized in that: Also includes: Detect whether the driver has turned on the inter-wheel differential lock; When it is detected that the driver turns on the inter-wheel differential lock, the inter-axle differential control is forcibly activated.

7. The inter-axle differential speed control method according to claim 6, characterized in that: Also includes: Detect whether the driver turns off the driving anti-skid function; When it is detected that the driver turns off the driving anti-skid function, the inter-axle differential control is forcibly turned off, wherein the priority of the forced turning off is higher than the forced activation.

8. An inter-axle differential control device, characterized in that: Applicable to a vehicle having a first drive axle and a second drive axle, comprising: A parameter acquisition module, used for acquiring driving parameters of the vehicle, wherein the driving parameters include vehicle speed, steering angle, throttle opening, and output rotation speeds of the first drive axle and the second drive axle; a speed control module, configured to, when the absolute value of the steering angle is less than a preset angle threshold, the throttle opening is less than a preset opening threshold, and the vehicle speed is less than a preset speed threshold, determine that a speed control condition is satisfied, and perform the speed control on the first drive axle and the second drive axle so that the output speeds of the first drive axle and the second drive axle are kept consistent; The slip control module is used to determine the slip rates of the first drive axle and the second drive axle according to the driving parameters when it is determined that the speed control condition is not met, and to increase the torque output of the other drive axle when the slip rate of one drive axle is greater than a preset slip rate threshold.

9. An electronic device, characterized in that: include: processor; as well as A memory arranged to store computer executable instructions, which when executed cause the processor to perform the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores one or more programs, which, when executed by an electronic device including a plurality of application programs, enable the electronic device to execute the method according to any one of claims 1 to 7.

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