A control method and device of a double-bridge electric drive axle, a vehicle and a medium

Abstract

The application discloses a control method and device of a double-bridge electric drive bridge, a vehicle and a medium, the double-bridge electric drive bridge comprising a middle bridge and a rear bridge with different gear numbers, comprising: determining a to-be-shifted electric drive bridge according to an obtained gear shifting instruction and a pre-constructed gear mapping relationship; wherein the gear mapping relationship is a corresponding relationship among system gears, a vehicle speed value range corresponding to the system gears and physical gears of the double-bridge electric drive bridge; determining a gear shifting priority of the to-be-shifted electric drive bridge according to the gear number; and controlling the to-be-shifted electric drive bridge to shift gears according to the gear shifting priority based on a preselected gear shifting reference; wherein the gear shifting reference is used to equivalently regard the middle bridge and the rear bridge as the same output shaft speed. Thus, the heterogeneous configuration takes into account the cost and power performance at the same time, and based on the gear mapping relationship and the gear shifting reference, it is ensured that the gear shifting instruction is correctly mapped to the corresponding electric drive bridge. In addition, based on the gear shifting priority, the gear shifting avoids the risk of motor overspeed and ensures the gear shifting safety and reliability.

Description

Technical Field

[0001] This application relates to the field of vehicle drive system control technology, and in particular to a control method, device, vehicle, and medium for a dual-bridge electric drive axle. Background Technology

[0002] With the continuous development of electric drive axle technology, dual-axle electric drive axles are widely used in heavy-duty trucks and other fields. Currently, in dual-axle electric drive axle control schemes, the middle and rear axles typically adopt a homogeneous configuration with the same number of gears, such as dual 2-speed axles or dual 4-speed axles. For homogeneous dual axles, since the transmission characteristics of the two axles are consistent, shift control is relatively simple, and the same or symmetrical shift strategies can be adopted.

[0003] However, in practical applications, dual 2-speed axles are less expensive but suffer from insufficient climbing power. Dual 4-speed axles offer strong power but are more expensive. When using heterogeneous gear configurations (i.e., the middle and rear axles have different numbers of gears), the speed ratio range, shift timing, and output shaft speed characteristics of the two axles differ significantly. Existing homogeneous shift control methods cannot be directly applied, easily leading to problems such as asynchronous shifting, power interruption, or even motor overspeed.

[0004] Therefore, how to safely shift gears on a heterogeneous dual-axle electric drive axle while balancing the cost and performance of the dual-axle electric drive axle and ensuring vehicle safety and reliability is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, one aspect of this application provides a control method for a dual-bridge electric drive axle, the dual-bridge electric drive axle comprising a middle axle and a rear axle with different numbers of gears; the method includes: Obtain shift commands used to adjust the system gears; Based on the shift command and the pre-built gear mapping relationship, the electric drive axle to be shifted is determined from the dual-axle electric drive axle; wherein, the gear mapping relationship is the correspondence between the system gear, the vehicle speed range corresponding to the system gear, and the physical gear of the dual-axle electric drive axle; The shift priority of the electric drive axle to be shifted is determined based on the number of gears. Based on a pre-selected shift reference, the electric drive bridge to be shifted is controlled to shift gears according to the shift priority; wherein, the shift reference is used to make the middle bridge and the rear bridge equivalent to the same output shaft speed.

[0006] Optionally, the step of constructing the gear mapping relationship includes: The transmission ratios of the middle axle and the rear axle are obtained respectively; Based on the transmission ratio and the preset maximum motor speed, determine the maximum vehicle speed of the middle axle and the rear axle in each physical gear. The system gear is generated based on the physical gear position of the middle axle and the physical gear position of the rear axle; The physical gear of the middle axle is matched with the physical gear of the rear axle to determine the upper limit of the corresponding speed range under the same system gear, which is the smaller of the maximum speed of the middle axle and the maximum speed of the rear axle. Establish a one-to-one correspondence between the system gears, the physical gears of the middle axle, and the physical gears of the rear axle, and associate each system gear with a corresponding vehicle speed range to obtain the gear mapping relationship.

[0007] Optionally, the upper limit value is the difference between the smaller value and the preset value; the preset value corresponds one-to-one with the system gear, and the preset value is different for different system gears.

[0008] Optionally, the shift command includes upshift command and downshift command; determining the shift priority of the electric drive axle to be shifted based on the number of gears includes: Compare whether the number of gears on the middle axle is less than the number of gears on the rear axle; If the shift priority is less than the specified value, when the shift command is an upshift command, the shift priority of the middle axle is higher than that of the rear axle; when the shift command is a downshift command, the shift priority of the rear axle is higher than that of the middle axle. If the shift priority is greater than the value of the shift command, when the shift command is an upshift command, the shift priority of the rear axle is higher than that of the middle axle; when the shift command is a downshift command, the shift priority of the middle axle is higher than that of the rear axle.

[0009] Optionally, the step of setting the shift reference includes: The axle with the smaller number of gears between the middle axle and the rear axle is used as the reference electric drive axle, and the other is used as a non-reference electric drive axle. Based on the output shaft speed and throttle opening of the reference electric drive axle, the shift line of the system gear is set; the shift line is the output shaft speed threshold that triggers shifting under different throttle openings; When the output shaft speed of the reference electric drive bridge exceeds the output shaft speed threshold, the reference electric drive bridge is triggered to shift gears. When the output shaft speed of the non-reference electric drive bridge exceeds the product of the output shaft speed threshold and the virtual speed ratio, the non-reference electric drive bridge is triggered to shift gears. Wherein, the virtual speed ratio is the ratio of the main reduction ratio of the non-reference electric drive bridge to the main reduction ratio of the reference electric drive bridge, and the virtual speed ratio is used to convert the output shaft speed of the non-reference electric drive bridge into the output shaft speed of the reference electric drive bridge.

[0010] Optionally, when the electric drive axle to be shifted includes the middle axle and the rear axle; controlling the electric drive axle to be shifted to perform shifting according to the shift priority includes: According to the shift priority, the shift command is executed after the torque of the high-priority electric drive axle to be shifted is cleared to zero; at the same time, the low-priority electric drive axle to be shifted performs torque compensation to maintain the total torque at the wheel end without interruption. Specifically, the torque compensation control increases the output torque of the low-priority electric drive bridge to compensate for the zeroing torque of the high-priority electric drive bridge.

[0011] Optionally, the middle axle and the rear axle include 2 physical gears and 4 physical gears.

[0012] Another aspect of this application provides a control device for a dual-bridge electric drive axle, the dual-bridge electric drive axle comprising a middle axle and a rear axle with different numbers of gears; the device includes: The shift command acquisition module is used to acquire shift commands for adjusting the system gears; The module for determining the electric drive axle to be shifted is used to determine the electric drive axle to be shifted from the dual-axle electric drive axles according to the shift command and the pre-built gear mapping relationship; wherein, the gear mapping relationship is the correspondence between the system gear, the vehicle speed range corresponding to the system gear, and the physical gear of the dual-axle electric drive axle; The shift priority determination module is used to determine the shift priority of the electric drive axle to be shifted based on the number of gears. The shift control module is used to control the electric drive bridge to shift gears according to the shift priority based on a pre-selected shift reference; wherein the shift reference is used to make the middle bridge and the rear bridge equivalent to the same output shaft speed.

[0013] Another aspect of this application provides a vehicle including a dual-axle electric drive axle, a memory, and a processor; The dual-bridge electric drive axle includes a middle axle and a rear axle with different numbers of gears; The memory stores computer programs that can run on the processor; The steps of the control method for the dual-bridge electric drive bridge are implemented when the processor executes the computer program.

[0014] Another aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the control method for the dual-bridge electric drive bridge.

[0015] The control method, device, vehicle, and medium for a dual-axle electric drive axle provided in this application offer the following advantages: By employing a heterogeneous configuration with different numbers of gears on the middle and rear axles, both cost and power performance are simultaneously achieved. Furthermore, under this heterogeneous configuration architecture, based on gear mapping relationships and shifting benchmarks, the middle and rear axles are equivalent to having the same output shaft speed, enabling shifting control in the heterogeneous configuration and ensuring that shifting commands are correctly mapped to the corresponding electric drive axles. In addition, determining shifting priority based on the number of gears avoids the risk of motor overspeed due to unreasonable combinations of low-gear and high-gear axles, thereby ensuring shifting safety and reliability. Attached Figure Description

[0016] Figure 1 A flowchart illustrating a control method for a dual-bridge electric drive bridge provided in an embodiment of this application; Figure 2 This is a schematic diagram of a dual-bridge electric drive bridge provided in an embodiment of this application; Figure 3 This is a schematic diagram of a two-speed electric drive bridge provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a four-speed electric drive bridge provided in an embodiment of this application; Figure 5 A schematic diagram of the architecture of a control system for a dual-bridge electric drive bridge provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a control device for a dual-bridge electric drive bridge provided in an embodiment of this application; Figure 7 This is a structural schematic diagram of a vehicle provided in an embodiment of this application.

[0017] The reference numerals in the attached diagram are as follows: 60 is the shift command acquisition module, 61 is the electric drive bridge to be shifted electric bridge determination module, 62 is the shift priority determination module, 63 is the shift control module, 70 is the memory, 71 is the processor, 72 is the display screen, 73 is the input / output interface, 74 is the communication interface, 75 is the power supply, 76 is the communication bus, 701 is the computer program, 707 is the operating system, and 703 is the data. Detailed Implementation

[0018] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0019] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0020] Figure 1 This is a flowchart illustrating a control method for a dual-bridge electric drive axle provided in an embodiment of this application. The dual-bridge electric drive axle includes a middle axle and a rear axle with different numbers of gears, such as... Figure 1 As shown, the method includes: S10: Obtain shift command for adjusting system gear position; First, it should be noted that the control method for the dual-axle electric drive bridge provided in this application can be applied to the vehicle control unit (VCU) or a domain controller in a vehicle; this application does not limit the application in this regard. The vehicle can be, but is not limited to, a mini-truck, a light truck, a heavy truck, or a light commercial vehicle (LCV).

[0021] Furthermore, the control method of this application is used to control a dual-bridge electric drive bridge, which includes a middle bridge and a rear bridge with different numbers of gears. For example, in an optional embodiment, the middle bridge has 2 physical gears and the rear bridge has 4 physical gears. This application does not limit the specific number of gears for the middle bridge and the rear bridge.

[0022] Figure 2 This is a schematic diagram of a dual-bridge electric drive bridge provided in an embodiment of this application. Figure 3 This is a schematic diagram of a two-speed electric drive bridge provided in an embodiment of this application. Figure 4 This is a schematic diagram of a four-speed electric drive bridge provided in an embodiment of this application.

[0023] To facilitate understanding, the following examples of dual-bridge electric drive systems will use two-speed and four-speed electric drive systems as examples, combined with... Figure 2 , Figure 3 and Figure 4 Provide examples. For instance... Figure 2 As shown, the vehicle's dual-axle electric drive system includes a middle axle and a rear axle. The middle axle uses a two-speed electric drive, while the rear axle uses a four-speed electric drive. The middle axle is connected to motor 1, and the rear axle is connected to motor 2. The two electric drive axles independently drive their respective wheels, forming a heterogeneous drive architecture with the middle and rear axles.

[0024] Specifically, such as Figure 3 As shown, the two-speed electric drive bridge includes a motor 1, an input shaft gear, an intermediate shaft gear, a shift shaft gear, an output shaft, and wheel ends. The torque of the motor 1 is transmitted to the intermediate shaft gear through the input shaft gear, and then to the wheel ends via the shift shaft gear to select different gear paths.

[0025] like Figure 4 As shown, the four-speed electric drive bridge includes a motor 2, an input shaft gear, an intermediate shaft gear, a shift shaft gear, an output shaft, and wheel ends. Figure 3 Compared to the two-speed axle shown, the four-speed axle has more sets of intermediate shaft gears and shift shaft gears, which can achieve four different transmission ratios.

[0026] Figure 5 This is a schematic diagram of the architecture of a control system for a dual-bridge electric drive bridge provided in an embodiment of this application. In an optional embodiment, such as... Figure 5 As shown, the control system uses the VCU as the core control unit, and communicates with Transmission Control Unit 1 (TCU1), Transmission Control Unit 2 (TCU2), Motor Control Unit 1 (MCU1), and Motor Control Unit 2 (MCU2) via a Controller Area Network (CAN) bus. TCU1 and MCU1 correspond to the middle axle (such as the two-speed electric drive axle in the example above), while TCU2 and MCU2 correspond to the rear axle (such as the four-speed electric drive axle in the example above).

[0027] In the above Figures 2 to 5 Based on this, in a specific embodiment, the VCU monitors the driver's accelerator pedal position, gear shift lever signal, and other operations in real time, as well as the vehicle speed, throttle opening, and other operating states. When the VCU determines that a change in the current system gear is needed based on the monitoring results, it generates a corresponding shift command. It should be noted that in the specific embodiment, the shift command includes upshift and downshift commands, and the shift command is calculated internally by the VCU to trigger the system gear switching.

[0028] S11: Based on the shift command and the pre-built gear mapping relationship, determine the electric drive axle to be shifted from the dual-axle electric drive axle; wherein, the gear mapping relationship is the correspondence between the system gear, the vehicle speed range corresponding to the system gear, and the physical gear of the dual-axle electric drive axle; In a specific embodiment, the VCU pre-stores gear mapping relationships. After obtaining the shift command, the VCU queries the gear mapping relationship based on the current system gear and the target system gear to determine the electric drive axle whose physical gear needs to be changed.

[0029] It is understandable that the gear mapping relationship includes the correspondence between the system gears, the physical gear of the intermediate gear, and the physical gear of the rear gear. Based on this mapping relationship, it can be determined whether the intermediate gear or the rear gear needs to be shifted. In a specific embodiment, the electric drive axle to be shifted may be only the intermediate axle, or it may be only the rear axle, or it may be necessary to shift both the intermediate axle and the rear axle simultaneously.

[0030] For example, if the current system gear corresponds to gear 1 on the middle axle and gear 1 on the rear axle, and the target system gear corresponds to gear 1 on the middle axle and gear 2 on the rear axle, then the electric drive axle to be shifted is only the rear axle. If the target system gear corresponds to gear 2 on the middle axle and gear 3 on the rear axle, then the electric drive axle to be shifted includes both the middle axle and the rear axle.

[0031] S12: Determine the shift priority of the electric drive axle to be shifted based on the number of gears; Because the middle axle and rear axle have different numbers of gears (e.g., the middle axle has 2 gears and the rear axle has 4 gears), when both axles need to shift gears simultaneously, it is necessary to determine which shifts first and which shifts last, i.e., to determine the shift priority of the middle and rear axles. Specifically, the VCU compares the number of gears on the middle and rear axles and combines this with the type of shift command (upshift or downshift) to determine the shift priority.

[0032] S13: Based on the pre-selected shift reference, control the electric drive bridge to be shifted to perform shifting according to the shift priority; wherein, the shift reference is used to make the middle bridge and the rear bridge equivalent to the same output shaft speed.

[0033] To unify the reference frame for shift control, this application pre-sets a shift reference. Furthermore, based on the shift priority of the above embodiments and this shift reference, the electric drive bridge to be shifted is controlled to perform the shift. It should be noted that, in the embodiments of this application, this shift reference is used to unify the output shaft speeds of the middle and rear axles, ensuring that shift commands are correctly mapped to the corresponding electric drive bridges, thus realizing shift control under heterogeneous electric drive bridges.

[0034] Specifically, such as Figure 5 As shown, the VCU sends control commands to the corresponding transmission control unit and motor control unit according to the shift priority and shift reference. In a specific embodiment, if the middle axle needs to shift gears, the VCU sends a target gear command to the TCU1 and a torque zeroing command to the MCU1. After the TCU1 reports that the shift has been completed, the VCU sends a torque recovery command to the MCU1.

[0035] Similarly, if the rear axle needs to shift gears, the VCU sends the target gear command to the TCU2 and simultaneously sends a torque zeroing command to the MCU2. After the TCU2 reports that the shift has been completed, the VCU sends a torque recovery command to the MCU2. If both axles need to shift gears sequentially, the VCU executes the above control process according to the shift priority based on the shift reference, thereby achieving heterogeneous shift control.

[0036] Therefore, the control method for the dual-bridge electric drive axle provided in this application adopts a heterogeneous configuration with different numbers of gears on the middle and rear axles, achieving a balance between cost and power performance. Simultaneously, under this heterogeneous configuration architecture, based on the gear mapping relationship and shift benchmark, the middle and rear axles are equivalent to having the same output shaft speed, realizing shift control for the heterogeneous configuration and ensuring that shift commands are correctly mapped to the corresponding electric drive axles. Furthermore, shift priority is determined according to the number of gears, avoiding the risk of motor overspeed due to an unreasonable combination of low-gear and high-gear axles, thereby ensuring shift safety and reliability.

[0037] In one optional embodiment, the step of constructing the gear mapping relationship includes: Obtain the transmission ratios of the middle axle and the rear axle respectively; Based on the transmission ratio and the preset maximum motor speed, determine the maximum vehicle speed of the middle axle and the rear axle in each physical gear. The system gears are generated based on the physical gears of the middle axle and the rear axle. Match the physical gear of the middle axle with the physical gear of the rear axle to the vehicle speed, so that under the same system gear, the upper limit of the corresponding vehicle speed range is limited by the smaller of the maximum vehicle speed of the middle axle and the maximum vehicle speed of the rear axle. Establish a one-to-one correspondence between the system gears, the physical gears of the middle axle, and the physical gears of the rear axle, and associate each system gear with a corresponding vehicle speed range to obtain the gear mapping relationship.

[0038] For ease of understanding, the following explanation will use an example where the middle axle has 2 physical gears and the rear axle has 4 physical gears to illustrate the gear mapping relationship. Table 1 is a schematic table of transmission ratios under different physical gears of a dual-axle electric drive axle provided in the embodiments of this application.

[0039] Table 1 shows the transmission ratios of a dual-bridge electric drive axle under different physical gear positions. In one optional embodiment, the transmission ratios of the middle and rear axles are shown in Table 1, wherein the physical gear ratios of the 2-speed electric drive axle (middle axle) are 59 for 1st gear and 16.85 for 2nd gear. The physical gear ratios of the 4-speed electric drive axle (rear axle) are 89 for 1st gear, 53 for 2nd gear, 30 for 3rd gear, and 16.89 for 4th gear.

[0040] Furthermore, the maximum speed of the middle and rear axles in each physical gear is determined according to formula (1): (1) in, The speed is expressed in kilometers per hour (km / h). This refers to the motor speed, expressed in revolutions per minute (r / pm). The radius of the wheel's rolling radius is expressed in meters (m). This represents the overall reduction ratio of the transmission system.

[0041] Table 2 is a schematic table of the maximum vehicle speed under different physical gears of a dual-bridge electric drive axle provided in the embodiments of this application. In the embodiments of this application, the maximum speed of the motor is preset to be 10000r / pm. According to the above calculation formula (1), the maximum vehicle speed under each physical gear shown in Table 2 can be obtained.

[0042] Table 2 shows the maximum vehicle speed of a dual-axle electric drive axle under different physical gears. Referring to Table 2, the maximum speed of the middle axle in 2nd gear is 32 km / h when physically in 1st gear, and 113 km / h when physically in 2nd gear. The maximum speed of the rear axle in 4th gear is 21 km / h when physically in 1st gear, 36 km / h when physically in 2nd gear, 63 km / h when physically in 3rd gear, and 113 km / h when physically in 4th gear.

[0043] Since the rear axle has four physical gears while the mid-axle only has two, this embodiment sets the system gears to four. System gear 1 corresponds to gear 1 on the mid-axle and gear 1 on the rear axle; system gear 2 corresponds to gear 1 on the mid-axle and gear 2 on the rear axle; system gear 3 corresponds to gear 2 on the mid-axle and gear 3 on the rear axle; and system gear 4 corresponds to gear 2 on the mid-axle and gear 4 on the rear axle. Table 3 is a schematic table of gear mapping relationships provided in this embodiment.

[0044] Table 3 is a schematic diagram of a gear mapping relationship. It should be noted that, in specific embodiments, to prevent the middle bridge motor from overspeeding, as shown in Table 3, the settings of middle bridge 1st gear and rear axle 3rd gear, and middle bridge 1st gear and rear axle 4th gear are not used when the system gear is in 3rd and 4th gear.

[0045] Furthermore, after generating the system gears, the physical gears of the middle axle and the rear axle are matched for vehicle speed to determine the range of vehicle speed values ​​under different system gears.

[0046] For example, referring to Table 3, in one optional embodiment, system gear 1 corresponds to the first gear of the middle axle (maximum speed 32 km / h) and the first gear of the rear axle (maximum speed 21 km / h), with the smaller of 21 km / h taken as the upper limit of the system gear. System gear 2 corresponds to the first gear of the middle axle (32 km / h) and the second gear of the rear axle (36 km / h), with the smaller of 32 km / h taken as the upper limit.

[0047] System gear 3 corresponds to the middle axle's 2nd gear (113 km / h) and the rear axle's 3rd gear (63 km / h), with the smaller of 63 km / h as the upper limit. System gear 4 corresponds to the middle axle's 2nd gear (113 km / h) and the rear axle's 4th gear (113 km / h), with the smaller of 113 km / h as the upper limit.

[0048] Therefore, the physical gears of the system, the middle axle, and the rear axle are mapped one-to-one, and associated with the corresponding vehicle speed range, thus obtaining the gear mapping relationship shown in Table 3.

[0049] In this embodiment of the application, the speed limit of each system gear is reasonably limited by speed matching to ensure that the speed range of the middle axle and the rear axle is coordinated and consistent under the same system gear, so as to provide data support for subsequent gear shifting.

[0050] Based on the above embodiments, as an optional embodiment, the upper limit value is the difference between the smaller value and the preset value; the preset value corresponds one-to-one with the system gear, and the preset value is different for different system gears.

[0051] Based on the gear mapping relationship shown in Table 3, in a specific embodiment, shifting gears when the vehicle speed reaches the upper limit of the speed range shown in Table 3 will cause the vehicle to shift gears frequently or generate shifting oscillations when it just reaches the theoretical maximum speed, thereby affecting the reliability and safety of vehicle shifting.

[0052] Therefore, in order to solve the above-mentioned technical problems, in this embodiment of the application, a certain margin is set for the upper limit of vehicle speed, that is, the upper limit is set as the difference between the smaller of the highest vehicle speed of the middle axle and the highest vehicle speed of the rear axle and a preset value.

[0053] For example, for system gear 1, the theoretical upper limit is 21 km / h, and the preset value can be set to 4 km / h. Then the upper limit of the actual vehicle speed range is 21-4=17 km / h, that is, system gear 1 is allowed to be used when the vehicle speed is below 17 km / h.

[0054] Similarly, the theoretical upper limit of system gear 2 is 32 km / h, and the preset value can be set to 6.3 km / h, resulting in an actual upper limit of 25.7 km / h. The theoretical upper limit of system gear 3 is 63 km / h, and the preset value can be set to 13 km / h, resulting in an actual upper limit of 50 km / h.

[0055] It should be noted that, in specific embodiments, this application does not limit the specific preset values ​​corresponding to different system gears, and can set them according to actual business needs. Furthermore, in another optional embodiment, referring to Table 3, a certain margin is also set for the maximum motor speed, that is, the maximum motor speed of 10000 r / pm is adjusted to 8000 r / pm.

[0056] Therefore, by introducing a preset value to adjust the upper limit of the vehicle speed range, frequent gear shifts near the critical speed can be avoided, thereby improving the reliability of gear shift control and the driving comfort of the vehicle.

[0057] In one optional embodiment, the shift command includes an upshift command and a downshift command; determining the shift priority of the electric drive axle to be shifted based on the number of gears includes: Compare whether the number of gears on the middle axle is less than the number of gears on the rear axle; If the shift priority is less than 1, when the shift command is an upshift command, the shift priority of the middle axle is higher than that of the rear axle; when the shift command is a downshift command, the shift priority of the rear axle is higher than that of the middle axle. If the value is greater than the specified value, when the shift command is an upshift command, the rear axle has a higher shift priority than the middle axle; when the shift command is a downshift command, the middle axle has a higher shift priority than the rear axle.

[0058] Similarly, for ease of understanding, the embodiments of this application will be described below using 2-speed and 4-speed dual-axle electric drive axle configurations as examples. In a specific embodiment, when a configuration with 2-speed for the middle axle and 4-speed for the rear axle is adopted, since the number of gears in the middle axle is less than the number of gears in the rear axle, during upshifting, if the rear axle upshifts first while the middle axle remains in a low gear (such as 1st gear for the middle axle and 3rd gear for the rear axle), the middle axle motor may experience overspeed risk after the vehicle speed increases due to the large transmission ratio of the 1st gear in the middle axle.

[0059] Therefore, in order to avoid the aforementioned risk of speeding, in this embodiment of the application, if the number of gears on the middle axle is less than the number of gears on the rear axle, and the shift command is upshift, the middle axle is prioritized to upshift, and the rear axle is upshifted only after the middle axle has completed the upshift.

[0060] Similarly, during downshifting, if the middle axle downshifts first while the rear axle remains in a higher gear (e.g., the middle axle is in 1st gear and the rear axle is in 4th gear), it will also cause the middle axle motor to overspeed. Therefore, in this embodiment, the rear axle downshifts first during downshifting.

[0061] Based on the above analysis, it can be inferred that if the middle axle has 4 gears and the rear axle has 2 gears, that is, the number of gears in the middle axle is greater than that in the rear axle, in order to avoid the risk of speeding, in this heterogeneous configuration, when upshifting, the rear axle will be prioritized to upshift, and when downshifting, the middle axle will be prioritized to downshift.

[0062] Therefore, based on the comparison results of the number of gears in the middle and rear axles, corresponding shift priority rules are formulated to avoid the risk of motor overspeed caused by improper gear combinations, thereby ensuring the shifting safety of the heterogeneous dual-bridge electric drive axle.

[0063] In one optional embodiment, the step of setting the shift reference includes: The axle with the smaller number of gears between the middle and rear axles is used as the reference electric drive axle, and the other is used as a non-reference electric drive axle. Based on the output shaft speed and throttle opening of the reference electric drive axle, the shift line of the system gear is set; the shift line is the output shaft speed threshold that triggers shifting under different throttle openings. When the output shaft speed of the reference electric drive bridge exceeds the output shaft speed threshold, the reference electric drive bridge is triggered to shift gears. When the output shaft speed of the non-reference electric drive bridge exceeds the product of the output shaft speed threshold and the virtual speed ratio, the non-reference electric drive bridge is triggered to shift gears. The virtual speed ratio is the ratio of the main reduction ratio of the non-reference electric drive bridge to the main reduction ratio of the reference electric drive bridge. The virtual speed ratio is used to convert the output shaft speed of the non-reference electric drive bridge into the output shaft speed of the reference electric drive bridge.

[0064] For ease of understanding, the embodiments of this application will be described below using 2-speed and 4-speed dual-axle electric drive bridge configurations as examples. Based on this, in this example, the number of gears on the middle axle is relatively small, so the middle axle is used as the reference electric drive bridge, and the rear axle is used as a non-reference electric drive bridge.

[0065] In a specific embodiment, gear shifting is triggered when the output shaft speed and throttle opening of the intermediate axle meet certain conditions. For the reference electric drive axle (intermediate axle), the actual output shaft speed of the intermediate axle is directly compared with the output shaft speed threshold; if it exceeds the threshold, gear shifting is triggered.

[0066] In another alternative embodiment, for a non-reference electric drive axle (rear axle), if the main reduction ratio of the rear axle is different from that of the middle axle, that is, the vehicle speeds of the middle axle and the rear axle are not the same, the actual output shaft speed of the rear axle cannot be directly compared with the output shaft speed threshold as the reference for triggering gear shifting of the rear axle.

[0067] To achieve gear shifting in the heterogeneous dual-bridge electric drive axle, a virtual gear ratio is set based on the main reduction ratios of the middle and rear axles, i.e., the virtual gear ratio. =Non-reference electric drive axle main reduction ratio / Reference electric drive axle main reduction ratio. For example, Figure 3 and Figure 4 As shown, when the rear axle final drive ratio is 3.4 and the middle axle final drive ratio is 3.6, =3.4 / 3.6≈0.94.

[0068] In a specific embodiment, the actual output shaft speed of the rear axle With the actual output shaft speed of the middle bridge ,satisfy Therefore, in order to ensure that the rear axle triggers shifting at the same reference output shaft speed, the shifting trigger condition for the rear axle is as follows: ,in, This is the output shaft speed threshold.

[0069] Therefore, by using a virtual speed ratio, the output shaft speed of the non-reference electric drive bridge is equivalently converted to the output shaft speed of the reference electric drive bridge, thus solving the problem that the middle and rear axles cannot perform shift control under different references.

[0070] In one optional embodiment, when the electric drive axle to be shifted includes a middle axle and a rear axle; controlling the electric drive axle to be shifted to perform gear shifting according to shift priority includes: Based on the shift priority, the shift command is executed after the torque of the high-priority electric drive axle to be shifted is cleared to zero; at the same time, the low-priority electric drive axle to be shifted performs torque compensation to maintain the total torque at the wheel end without interruption. Among them, the electric drive bridge with low torque compensation control increases the output torque to compensate for the torque of the electric drive bridge with high priority when it is reset to zero.

[0071] In a specific embodiment where both the middle and rear axles need to shift gears simultaneously, for example, referring to Table 3, shifting from system gear 2 to system gear 3 requires the middle axle to shift from gear 1 to gear 2 and the rear axle to shift from gear 2 to gear 3.

[0072] The VCU determines the shift priority of the middle axle and the rear axle according to the method described in the above embodiment. Taking a configuration with the middle axle in 2nd gear and the rear axle in 4th gear and executing an upshift command as an example, in this example, the upshift priority of the middle axle is higher than that of the rear axle.

[0073] During gear shifting, the VCU sends a torque zeroing command to the motor controller of the middle axle, reducing the output torque of the middle axle motor to zero to disengage the current gear. At the same time, the VCU controls the rear axle to increase its output torque to compensate for the torque portion of the middle axle that was zeroed, thus maintaining continuous total torque at the wheel ends, achieving gear shifting control without power interruption.

[0074] Specifically, in the example above, if the current wheel-end torque requirement is... The output torque of the middle axle before shifting gears is The rear axle output torque is ,but When the mid-axle torque is reset to zero, the output torque changes. The value is 0, at which point the VCU controls the rear axle to increase the output torque to 0. Thus maintaining the total torque at the wheel end equal to .

[0075] Once the intermediate axle completes the gear shift and restores torque, the rear axle gradually withdraws from compensation, returning to normal torque distribution. Similarly, in another optional embodiment, if the rear axle is the higher-priority axle for gear shifting, the intermediate axle performs torque compensation.

[0076] Therefore, by clearing the torque of the electric drive axle with high shift priority and compensating for the torque of the electric drive axle with low shift priority, the heterogeneous dual-axle electric drive axles can achieve uninterrupted shifting when shifting gears simultaneously, avoiding the jerking sensation caused by shifting gears and improving vehicle comfort.

[0077] Understandably, in specific embodiments, dual 2-speed axles are less expensive but suffer from insufficient climbing power. Dual 4-speed axles, on the other hand, offer strong power but are more expensive. Therefore, to balance cost and performance, in one optional embodiment, the middle and rear axles include 2 physical gears and 4 physical gears, respectively.

[0078] See Figure 2 , Figure 3 and Figure 4 This invention provides a method for controlling a dual-axle electric drive axle with two physical gears on the middle axle and four physical gears on the rear axle. Combined with the control method for the dual-axle electric drive axle provided in the above embodiments, it reduces costs while ensuring sufficient power performance. It also achieves smooth and safe gear shifting control of the heterogeneous dual-axle electric drive axle, ensuring vehicle safety and reliability.

[0079] In the above embodiments, the control method for the dual-bridge electric drive bridge has been described in detail. This application also provides an embodiment of the control device for the dual-bridge electric drive bridge.

[0080] Figure 6 This is a schematic diagram of the structure of a control device for a dual-bridge electric drive bridge provided in an embodiment of this application, as shown below. Figure 6 As shown, the device includes: The shift command acquisition module 60 is used to acquire shift commands for adjusting the system gears; The module 61 for determining the electric drive axle to be shifted is used to determine the electric drive axle to be shifted from the dual-axle electric drive axles according to the shift command and the pre-built gear mapping relationship; wherein, the gear mapping relationship is the correspondence between the system gear, the vehicle speed range corresponding to the system gear, and the physical gear of the dual-axle electric drive axle. The shift priority determination module 62 is used to determine the shift priority of the electric drive axle to be shifted based on the number of gears. The shift control module 63 is used to control the electric drive bridge to shift gears according to the shift priority based on the pre-selected shift reference; wherein, the shift reference is used to make the middle bridge and the rear bridge equivalent to the same output shaft speed.

[0081] Furthermore, the control device for the dual-bridge electric drive bridge provided in this application embodiment also includes: The transmission ratio acquisition module is used to acquire the transmission ratios of the middle axle and the rear axle respectively. The maximum speed determination module is used to determine the maximum speed of the middle axle and the rear axle in each physical gear according to the transmission ratio and the preset maximum motor speed. The system gear generation module is used to generate system gears based on the physical gears of the middle axle and the rear axle. The speed matching module is used to match the physical gear of the middle axle with the physical gear of the rear axle, so that under the same system gear, the upper limit of the corresponding speed range is limited by the smaller of the maximum speed of the middle axle and the maximum speed of the rear axle. The mapping relationship establishment module is used to establish a one-to-one correspondence between the system gears, the physical gears of the middle axle, and the physical gears of the rear axle, and to associate each system gear with the corresponding vehicle speed range to obtain the gear mapping relationship.

[0082] The gear quantity comparison module is used to compare whether the number of gears on the middle axle is less than the number of gears on the rear axle; the shift commands include upshift commands and downshift commands; if it is less, the first setting module is called; if it is greater, the second setting module is called. The first setting module is used to prioritize the shifting of the middle axle over the rear axle when the shifting command is an upshift command; and to prioritize the shifting of the rear axle over the middle axle when the shifting command is a downshift command. The first setting module is used to prioritize the rear axle over the middle axle when the shift command is an upshift command, and to prioritize the middle axle over the rear axle when the shift command is a downshift command.

[0083] The reference determination module is used to select the electric drive axle with the smaller number of gears between the middle axle and the rear axle as the reference electric drive axle, and the other is a non-reference electric drive axle. The shift line setting module is used to set the shift line of the system gear based on the output shaft speed and throttle opening of the reference electric drive axle; the shift line is the output shaft speed threshold that triggers shifting under different throttle openings; The first shift trigger determination module is used to trigger the shift of the reference electric drive bridge when the output shaft speed of the reference electric drive bridge exceeds the output shaft speed threshold. The first shift trigger determination module is used to trigger the shift of the non-reference electric drive bridge when the output shaft speed of the non-reference electric drive bridge exceeds the product of the output shaft speed threshold and the virtual speed ratio; wherein, the virtual speed ratio is the ratio of the main reduction ratio of the non-reference electric drive bridge to the main reduction ratio of the reference electric drive bridge, and the virtual speed ratio is used to convert the output shaft speed of the non-reference electric drive bridge into the output shaft speed of the reference electric drive bridge.

[0084] The uninterrupted power shifting module is used to control the high-priority electric drive axle to be shifted to execute the shift command after the torque is cleared to zero, according to the shift priority; at the same time, it controls the low-priority electric drive axle to be shifted to perform torque compensation to maintain the total torque at the wheel end without interruption; wherein, the torque compensation control increases the output torque of the low-priority electric drive axle to be shifted to compensate for the torque cleared to zero by the high-priority electric drive axle to be shifted.

[0085] Figure 7This is a schematic diagram of the structure of a vehicle provided in an embodiment of this application, such as... Figure 7 As shown, the vehicle includes: a dual-axle electric drive axle 77; Memory 70 is used to store computer programs; The processor 71 is used to execute computer programs to implement the steps of the control method for the dual-bridge electric drive bridge as described in the above embodiments.

[0086] It should be noted that the vehicles in the embodiments of this application include, but are not limited to, mini-trucks, light trucks, heavy trucks, and light commercial vehicles (LCVs).

[0087] The processor 71 may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor 71 may be implemented using at least one of the following hardware forms: Digital Signal Processor (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). The processor 71 may also include a main processor and a coprocessor. The main processor, also known as the Central Processing Unit (CPU), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor 71 may integrate a Graphics Processing Unit (GPU), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, the processor 71 may also include an Artificial Intelligence (AI) processor, which is used to handle computational operations related to machine learning.

[0088] The memory 70 may include one or more computer-readable storage media, which may be non-transitory. The memory 70 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In this embodiment, the memory 70 is used to store at least the following computer program 701, which, after being loaded and executed by the processor 71, is capable of implementing the relevant steps of the dual-bridge electric drive bridge control method disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory 70 may also include an operating system 702 and data 703, and the storage method may be temporary or permanent storage. The operating system 702 may include Windows, Unix, Linux, etc. The data 703 may include, but is not limited to, the relevant data involved in the dual-bridge electric drive bridge control method.

[0089] In some embodiments, the vehicle may also include a display screen 72, an input / output interface 73, a communication interface 74, a power supply 75, and a communication bus 76.

[0090] Those skilled in the art will understand that Figure 7 The structure shown does not constitute a limitation on the vehicle and may include more or fewer components than illustrated.

[0091] The vehicle provided in this application includes a dual-axle electric drive axle, a memory, and a processor. When the processor executes the program stored in the memory, it can implement the control method of the dual-axle electric drive axle described in the above embodiments.

[0092] It should be noted that although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order shown or sequentially, or requiring all illustrated operations to be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system modules and components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Claims

1. A control method for a dual-bridge electric drive bridge, characterized in that, The dual-bridge electric drive axle includes a middle axle and a rear axle with different numbers of gears; the method includes: Obtain shift commands used to adjust the system gears; Based on the shift command and the pre-built gear mapping relationship, the electric drive axle to be shifted is determined from the dual-axle electric drive axle; wherein, the gear mapping relationship is the correspondence between the system gear, the vehicle speed range corresponding to the system gear, and the physical gear of the dual-axle electric drive axle; The shift priority of the electric drive axle to be shifted is determined based on the number of gears. Based on a pre-selected shift reference, the electric drive bridge to be shifted is controlled to shift gears according to the shift priority; wherein, the shift reference is used to make the middle bridge and the rear bridge equivalent to the same output shaft speed.

2. The control method for a dual-bridge electric drive bridge as described in claim 1, characterized in that, The steps for constructing the gear mapping relationship include: The transmission ratios of the middle axle and the rear axle are obtained respectively; Based on the transmission ratio and the preset maximum motor speed, determine the maximum vehicle speed of the middle axle and the rear axle in each physical gear. The system gear is generated based on the physical gear position of the middle axle and the physical gear position of the rear axle; The physical gear of the middle axle is matched with the physical gear of the rear axle to determine the upper limit of the corresponding speed range under the same system gear, which is the smaller of the maximum speed of the middle axle and the maximum speed of the rear axle. Establish a one-to-one correspondence between the system gears, the physical gears of the middle axle, and the physical gears of the rear axle, and associate each system gear with a corresponding vehicle speed range to obtain the gear mapping relationship.

3. The control method for the dual-bridge electric drive bridge as described in claim 2, characterized in that, The upper limit value is the difference between the smaller value and the preset value; the preset value corresponds one-to-one with the system gear, and the preset value is different for different system gears.

4. The control method for a dual-bridge electric drive bridge as described in claim 1, characterized in that, The shift commands include upshift commands and downshift commands; the shift priority of the electric drive axle to be shifted is determined according to the number of gears, including: Compare whether the number of gears on the middle axle is less than the number of gears on the rear axle; If the shift priority is less than the specified value, when the shift command is an upshift command, the shift priority of the middle axle is higher than that of the rear axle; when the shift command is a downshift command, the shift priority of the rear axle is higher than that of the middle axle. If the shift priority is greater than the value of the shift command, when the shift command is an upshift command, the shift priority of the rear axle is higher than that of the middle axle; when the shift command is a downshift command, the shift priority of the middle axle is higher than that of the rear axle.

5. The control method for a dual-bridge electric drive bridge as described in claim 1, characterized in that, The steps for setting the shift reference include: The axle with the smaller number of gears between the middle axle and the rear axle is used as the reference electric drive axle, and the other is used as a non-reference electric drive axle. Based on the output shaft speed and throttle opening of the reference electric drive axle, the shift line of the system gear is set; the shift line is the output shaft speed threshold that triggers shifting under different throttle openings; When the output shaft speed of the reference electric drive bridge exceeds the output shaft speed threshold, the reference electric drive bridge is triggered to shift gears. When the output shaft speed of the non-reference electric drive bridge exceeds the product of the output shaft speed threshold and the virtual speed ratio, the non-reference electric drive bridge is triggered to shift gears. Wherein, the virtual speed ratio is the ratio of the main reduction ratio of the non-reference electric drive bridge to the main reduction ratio of the reference electric drive bridge, and the virtual speed ratio is used to convert the output shaft speed of the non-reference electric drive bridge into the output shaft speed of the reference electric drive bridge.

6. The control method for a dual-bridge electric drive bridge as described in claim 1, characterized in that, When the electric drive axle to be shifted includes the middle axle and the rear axle; controlling the electric drive axle to be shifted to perform shifting according to the shifting priority includes: According to the shift priority, the shift command is executed after the torque of the high-priority electric drive axle to be shifted is cleared to zero; at the same time, the low-priority electric drive axle to be shifted performs torque compensation to maintain the total torque at the wheel end without interruption. Specifically, the torque compensation control increases the output torque of the low-priority electric drive bridge to compensate for the zeroing torque of the high-priority electric drive bridge.

7. The control method for a dual-bridge electric drive bridge as described in any one of claims 1 to 6, characterized in that, The middle axle and the rear axle include 2 physical gears and 4 physical gears, respectively.

8. A control device for a dual-bridge electric drive bridge, characterized in that, The dual-bridge electric drive axle includes a middle axle and a rear axle with different numbers of gears; the device includes: The shift command acquisition module is used to acquire shift commands for adjusting the system gears; The module for determining the electric drive axle to be shifted is used to determine the electric drive axle to be shifted from the dual-axle electric drive axles according to the shift command and the pre-built gear mapping relationship; wherein, the gear mapping relationship is the correspondence between the system gear, the vehicle speed range corresponding to the system gear, and the physical gear of the dual-axle electric drive axle; The shift priority determination module is used to determine the shift priority of the electric drive axle to be shifted based on the number of gears. The shift control module is used to control the electric drive bridge to shift gears according to the shift priority based on a pre-selected shift reference; wherein the shift reference is used to make the middle bridge and the rear bridge equivalent to the same output shaft speed.

9. A vehicle, characterized in that, Includes a dual-bridge electric drive, memory, and processor; The dual-bridge electric drive axle includes a middle axle and a rear axle with different numbers of gears; The memory stores computer programs that can run on the processor; When the processor executes the computer program, it implements the steps of the control method for the dual-bridge electric drive bridge according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the control method for the dual-bridge electric drive bridge according to any one of claims 1 to 7.

Images