Electric drive axle control system and commercial vehicle

Abstract

The application relates to the technical field of electric drive axle of commercial vehicles, in particular to an electric drive axle control system and a commercial vehicle. The electric drive axle control system comprises a left two-axle motor, a right two-axle motor, a left two-axle wheel, a right two-axle wheel, a three-axle motor, a differential, a left three-axle wheel and a right three-axle wheel and a controller; the left two-axle motor is connected with the left two-axle wheel through a left two-axle transmission mechanism, the right two-axle motor is connected with the right two-axle wheel through a right two-axle transmission mechanism, and the controller can control the driving torque of the left two-axle motor and the right two-axle motor respectively; the three-axle motor is connected with the differential through a three-axle transmission mechanism, and the differential is connected with the left three-axle wheel and the right three-axle wheel respectively; when the actual vehicle speed of the whole vehicle is greater than a predetermined high-speed limit value, the controller controls the three-axle motor to start and controls the left two-axle motor and the right two-axle motor to be closed. The electric drive axle control system and the commercial vehicle solve the technical problems existing in the existing electric drive axle of commercial vehicles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric drive axle of commercial vehicle, and particularly to an electric drive axle control system and a commercial vehicle. BACKGROUND

[0002] For the electric drive axle of commercial vehicle, the traditional electric drive axle of commercial vehicle usually includes two configurations of distributed type and central centralized type. The distributed type can realize independent control of left and right wheels, but due to large axle load of heavy commercial vehicle, speed control error is prone to occur, which causes tire wear, so the distributed type is rarely applied.

[0003] The central centralized type adopts a single motor or a double motor, and both need to realize torque distribution to the left and right sides through a common mechanical differential. However, the central centralized type cannot realize independent control of the two sides of driving and cannot realize the demand of chassis vector control. SUMMARY

[0004] The present application aims to provide an electric drive axle control system and a commercial vehicle, thereby solving the above technical problems existing in the prior art.

[0005] According to a first aspect of the present application, an electric drive axle control system is provided, which includes a left two-axle motor, a right two-axle motor, a left two-axle wheel, a right two-axle wheel, a left two-axle transmission mechanism, a right two-axle transmission mechanism, a three-axle motor, a differential, a left three-axle wheel, a right three-axle wheel, a three-axle transmission mechanism, and a controller. The left two-axle motor is connected with the left two-axle wheel through the left two-axle transmission mechanism, the right two-axle motor is connected with the right two-axle wheel through the right two-axle transmission mechanism, and the controller can control driving torque of the left two-axle motor and the right two-axle motor respectively. The three-axle motor is connected with the differential through the three-axle transmission mechanism, and the differential is connected with the left three-axle wheel and the right three-axle wheel respectively. The controller pre-stores a predetermined high-speed limit value. When the actual vehicle speed is greater than the predetermined high-speed limit value, the controller controls the three-axle motor to start and controls the left two-axle motor and the right two-axle motor to be closed.

[0006] In any of the above technical solutions, further, the controller pre-stores a first threshold value, and the controller can determine a target acceleration a t of the vehicle according to vehicle throttle input. When the vehicle starts, the controller controls the three-axle motor to start. When the difference between the target acceleration a t of the vehicle and the actual acceleration a v of the vehicle exceeds the first threshold value, the controller controls the left two-axle motor and the right two-axle motor to start until the actual acceleration a v of the vehicle reaches the target acceleration at The controller controls the left two-axle motor and the right two-axle motor to be turned off.

[0007] In any of the above technical solutions, further, the electric drive axle control system further comprises a left one-axle wheel, a right one-axle wheel and a TCS system; the controller pre-stores a set value V th and a predetermined ideal vehicle speed value, the controller is capable of determining a corresponding vehicle speed V 3L according to the wheel speed of the left three-axle wheel, determining a corresponding vehicle speed V 3R according to the wheel speed of the right three-axle wheel, and determining a corresponding vehicle speed V fa according to the wheel speed of the left one-axle wheel and the right one-axle wheel; when the vehicle starts, if (V 3L +V 3R ) / 2-V fa >V th , the TCS system is turned on, the controller controls the left two-axle motor and the right two-axle motor to be started, and the three-axle motor to be turned off; during the operation of the left two-axle motor and the right two-axle motor, the controller controls the driving torque of the left two-axle motor and the right two-axle motor respectively, so that the wheel speed corresponding to the left two-axle wheel and the right two-axle wheel reaches the predetermined ideal vehicle speed value.

[0008] In any of the above technical solutions, further, the predetermined ideal vehicle speed value V t =(1+S)V fa , wherein S is a driving slip rate; when the wheel speed corresponding to the left two-axle wheel and the right two-axle wheel of the vehicle reaches the predetermined ideal vehicle speed value V t , the controller controls the three-axle motor to be started, and controls the left two-axle motor and the right two-axle motor to be turned off.

[0009] In any of the above technical solutions, further, the controller pre-stores a second threshold value, the controller is capable of determining an expected yaw rate w t according to the steering wheel input, and when the three-axle motor is in energy recovery, if the difference between the actual yaw rate w z of the vehicle and the expected yaw rate w t of the vehicle exceeds the second threshold value, the controller controls the left two-axle motor or the right two-axle motor to be started until the actual yaw rate w z of the vehicle reaches the expected yaw rate w t of the vehicle, and then controls the left two-axle motor or the right two-axle motor to be turned off.

[0010] In any of the above technical solutions, further, when the three-axle motor is in energy recovery, if the difference between the actual yaw rate w z of the vehicle and the expected yaw rate w t of the vehicle exceeds the second threshold value, the controller controls the left two-axle motor or the right two-axle motor to be started until the actual yaw rate w z of the vehicle reaches the expected yaw rate w t of the vehicle, and then controls the left two-axle motor or the right two-axle motor to be turned off.z the difference between the actual yaw rate w t of the vehicle and the expected yaw rate w z of the vehicle is positive, the controller increases the regenerative braking torque of the right two-axle motor; and t the difference between the actual yaw rate w t of the vehicle and the expected yaw rate w z of the vehicle is negative, the controller increases the driving torque of the left two-axle motor.

[0011] In any of the above technical solutions, further, the controller can determine the expected yaw rate w t according to the steering wheel input; when the vehicle is turning left, if the difference between the actual yaw rate w z of the vehicle and the expected yaw rate w t of the vehicle is positive, the controller increases the driving torque of the left two-axle motor; and if the difference between the actual yaw rate w z of the vehicle and the expected yaw rate w t of the vehicle is negative, the controller increases the driving torque of the right two-axle motor; when the vehicle is turning right, if the difference between the actual yaw rate w z of the vehicle and the expected yaw rate w t of the vehicle is positive, the controller increases the driving torque of the right two-axle motor; and if the difference between the actual yaw rate w z of the vehicle and the expected yaw rate w t of the vehicle is negative, the controller increases the driving torque of the left two-axle motor.

[0012] In any of the above technical solutions, further, the controller can determine the corresponding wheel slip ratio according to the wheel speed of the left one-axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the right one-axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the left two-axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the right two-axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the left three-axle wheel, and determine the corresponding wheel slip ratio according to the wheel speed of the right three-axle wheel; when the vehicle is braking on a split road surface, if the wheel slip ratio of the left one-axle wheel is greater than the wheel slip ratio of the right one-axle wheel, the wheel slip ratio of the left two-axle wheel is greater than the wheel slip ratio of the right two-axle wheel, and the wheel slip ratio of the left three-axle wheel is greater than the wheel slip ratio of the right three-axle wheel, the controller controls the left one-axle wheel, the right one-axle wheel, the left two-axle wheel, the left three-axle wheel, and the right three-axle wheel to brake, and controls the torque of the right two-axle motor so that the right two-axle wheel generates driving force.

[0013] When the vehicle is braking on a split road surface, if the wheel slip rate of the left front wheel is less than the wheel slip rate of the right front wheel, the wheel slip rate of the left rear wheel is less than the wheel slip rate of the right rear wheel, and the wheel slip rate of the left rear wheel is less than the wheel slip rate of the right rear wheel, the controller controls the left front wheel, the right front wheel, the right rear wheel, the left rear wheel and the right rear wheel to brake, and controls the torque of the left rear motor so that the left rear wheel generates driving force.

[0014] In any of the above technical solutions, further, the three-axle transmission mechanism comprises a first shaft, a first gear, a second gear, a second shaft, a first-gear driving gear, a second-gear driving gear, a third shaft, a first-gear driven gear, a second-gear driven gear, a synchronizer, a third gear and a transmission member;

[0015] The three-axle motor is connected with the first gear through the first shaft, the first gear is engaged with the second gear, the second gear, the first-gear driving gear and the second-gear driving gear are fixed on the second shaft, the first-gear driven gear and the second-gear driven gear are sleeved on the third shaft, the synchronizer and the third gear are fixed on the third shaft, the synchronizer is arranged between the first-gear driven gear and the second-gear driven gear, the first-gear driving gear is engaged with the first-gear driven gear, the second-gear driving gear is engaged with the second-gear driven gear, the third gear is connected with the differential through the transmission member, and the differential is connected with the left rear wheel and the right rear wheel through two half shafts respectively.

[0016] According to the second aspect of the present application, a commercial vehicle is provided, which comprises the electric drive axle control system as described above.

[0017] The electric drive axle control system of the present application comprises a left rear motor, a right rear motor, a left rear wheel, a right rear wheel, a left rear transmission mechanism, a right rear transmission mechanism, a three-axle motor, a differential, a left rear wheel, a right rear wheel, a three-axle transmission mechanism and a controller. The left rear motor is connected with the left rear wheel through the left rear transmission mechanism, the right rear motor is connected with the right rear wheel through the right rear transmission mechanism, and the controller can control the driving torque of the left rear motor and the right rear motor respectively. The three-axle motor is connected with the differential through the three-axle transmission mechanism, and the differential is connected with the left rear wheel and the right rear wheel respectively. The controller pre-stores a predetermined high-speed limit value. When the actual vehicle speed of the vehicle is greater than the predetermined high-speed limit value, the controller controls the three-axle motor to start and controls the left rear motor and the right rear motor to be turned off.

[0018] According to the above technical features, the present application has the following beneficial effects:

[0019] The electric drive axle control system of the present application can independently control the driving torque of the left two-axle motor and the right two-axle motor respectively, so as to realize independent control of the left and right side driving torque; and when the whole vehicle is running at high speed, the controller only controls the three-axle motor to start, so that the whole vehicle can also avoid excessive wear of the tires when running at high speed on a curve. That is, the electric drive axle control system of the present application can realize independent control of the left and right wheel torque in special working conditions, and can also ensure that the left and right wheel speed difference is reasonably matched to prevent excessive wear of the tires when running at high speed on a curve.

[0020] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are specifically described below, and the accompanying drawings are described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0022] Figure 1 The overall principle schematic diagram of the electric drive axle control system of the embodiment of the present application is shown;

[0023] Figure 2 The structural schematic diagram of the three-axle transmission mechanism of the embodiment of the present application is shown.

[0024] Figure legend: 10-first shaft; 20-first gear; 30-second gear; 40-second shaft; 51-one gear driving gear; 52-two gear driving gear; 80-third shaft; 61-one gear driven gear; 62-two gear driven gear; 70-synchronizer; 90-third gear; 91-transmission member;

[0025] 100-left two-axle motor; 200-right two-axle motor; 300-left two-axle wheel; 400-right two-axle wheel; 500-three-axle motor; 600-differential; 700-left three-axle wheel; 800-right three-axle wheel; 900-controller; 1000-three-axle transmission mechanism; 2000-left two-axle transmission mechanism; 3000-right two-axle transmission mechanism. DETAILED DESCRIPTION

[0026] The following detailed description is presented to aid the reader in gaining a comprehensive understanding of the methods, apparatuses, and / or systems described herein. However, various changes, modifications, and equivalents can be used, and thus particular embodiments described herein are not intended as being exhaustive of what the present disclosure can provide. For example, although operations are described as following a certain order, embodiments can be practiced in any order that is practicable unless otherwise stated or required by the circumstances. Moreover, it is to be understood that certain features can be utilized twofold or threesold, just as they are described herein in multiple instances. Furthermore, to the extent that the terms "includes," "containing," "has," "having," and / or the like are used in the detailed description and / or claims, such terms are intended to be inclusive in a manner similar to the term "comprising" as an open term with the most possible scope, unless otherwise stated.

[0027] The described features can be implemented in different forms and are not to be construed as limited to the examples described herein. Rather, these described examples have been provided for illustrative purposes so that those skilled in the art will be able to implement the methods, apparatuses, and / or systems described herein in a variety of ways.

[0028] Throughout the specification, when an element (such as a layer, region, or substrate) is referred to as being "on" another element, "connected to" another element, "coupled to" another element, "adjacent to" another element, "on top of" another element, or "covering" another element, it can be directly on, connected to, coupled to, adjacent to, on top of, or covering the other element, or one or more other elements can be interposed therebetween. In contrast, when an element is referred to as being "directly on," "directly connected to," "directly coupled to," "directly adjacent to," "directly on top of," or "directly covering" another element, there are no other elements interposed therebetween.

[0029] As used herein, the term "and / or" includes any one and any combination of the associated items in the list.

[0030] Although terms such as "first" and "second" can be used herein to describe various elements, components, regions, layers, or sections, these elements, components, regions, layers, or sections should not be limited by these terms. Rather, these terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, the first element, component, region, layer, or section described in the examples described herein could also be called a second element, component, region, layer, or section, without departing from the teachings of the examples.

[0031] For ease of description, spatially relative terms, such as "on", "upper", "lower", "above", and "below", can be used herein for the purpose of illustrating one element's relationship to another element in the drawings. Such spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientations depicted in the drawings. For example, if the device in the drawings is turned over, elements described as being "on" or "above" other elements would then be oriented "below" or "on" the other elements. Thus, the term "on" can encompass both an "on" and "below" position depending on the spatial orientation of the device. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative terms used herein interpreted accordingly.

[0032] The terminology used herein is for the purpose of describing various examples only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has", "having" and the like are inclusive and open-ended and specify the presence of stated features, integers, operations, members, elements and / or groups but do not preclude the presence or addition of one or more other features, integers, operations, members, elements and / or groups thereof.

[0033] Variations in shapes that are shown in the drawings can occur as a result of manufacturing processes and / or tolerances. Thus, the examples described herein are not limited to the precise shapes shown in the drawings, but include variations in shapes that occur as a result of manufacturing processes.

[0034] Features of the examples described herein can be combined with one another in any manner, as would be apparent to one of skill in the art after understanding the disclosure provided herein. Furthermore, although examples described herein have various configurations, other configurations are possible as would be apparent to one of skill in the art after understanding the disclosure provided herein.

[0035] Before the present application, for commercial vehicle electric drive axle, the conventional commercial vehicle electric drive axle generally includes two configurations of distributed and central centralized, wherein the distributed configuration can realize independent control of left and right wheels, but due to large axle load of heavy commercial vehicle, speed control error is prone to occur, causing tire wear, so the distributed configuration is rarely applied. The central centralized configuration adopts single motor or double motor, both of which need to realize torque distribution to left and right sides through a shared mechanical differential, but the central centralized configuration cannot realize independent control of two-side driving and cannot realize the demand of chassis vector control.

[0036] In view of this, the first aspect of the present application provides an electric drive axle control system, thereby solving the above technical problems existing in the existing commercial vehicle electric drive axle. The following refers to the accompanying drawings to describe the electric drive axle control system in detail. Figure 1 and Figure 2The electric drive axle control system described in some embodiments of the present application is described.

[0037] As shown in Figure 1 , the electric drive axle control system of the present application is applied to a multi-axle driven commercial vehicle. The electric drive axle control system comprises a left two-axle motor 100, a right two-axle motor 200, a left two-axle wheel 300, a right two-axle wheel 400, a left two-axle transmission mechanism 2000, a right two-axle transmission mechanism 3000, a three-axle motor 500, a differential 600, a left three-axle wheel 700, a right three-axle wheel 800, a three-axle transmission mechanism 1000, and a controller 900.

[0038] Among them, the left two-axle motor 100 is connected with the left two-axle wheel 300 through the left two-axle transmission mechanism 2000, the right two-axle motor 200 is connected with the right two-axle wheel 400 through the right two-axle transmission mechanism 3000, and the controller 900 can control the driving torque of the left two-axle motor 100 and the right two-axle motor 200 respectively. That is, the two-axle adopts a left-right independent driving scheme, and the left two-axle wheel 300 and the right two-axle wheel 400 are driven by two single-sided driving motors through single-sided transmission mechanisms, and the driving torque and regenerative braking torque of the left two-axle wheel 300 and the right two-axle wheel 400 can be independently controlled.

[0039] Among them, the three-axle motor 500 is connected with the differential 600 through the three-axle transmission mechanism 1000, and the differential 600 is connected with the left three-axle wheel 700 and the right three-axle wheel 800 through two half shafts respectively. That is, the three-axle adopts a single motor central driving scheme, and the driving torque of the three-axle motor 500 is transmitted through the three-axle transmission mechanism 1000 and the differential 600, and then drives the left three-axle wheel 700 and the right three-axle wheel 800 through the left and right half shafts respectively.

[0040] Among them, the left two-axle motor 100, the right two-axle motor 200 and the three-axle motor 500 work under the control of the controller 900.

[0041] In embodiments of the present application, the electric drive axle control system further comprises a left one-axle wheel and a right one-axle wheel (front axle, not shown in the figure).

[0042] In embodiments of the present application, as shown in Figure 2 , the three-axle transmission mechanism 1000 comprises a first shaft 10, a first gear 20, a second gear 30, a second shaft 40, a first gear 51, a second gear 52, a third shaft 80, a first driven gear 61, a second driven gear 62, a synchronizer 70, a third gear 90 and a transmission member 91.

[0043] The three-axle motor 500 is connected with the first gear 20 through the first shaft 10, the first gear 20 is engaged with the second gear 30, the second gear 30, the first-gear driving gear 51 and the second-gear driving gear 52 are fixed on the second shaft 40, the first-gear driven gear 61 and the second-gear driven gear 62 are sleeved on the third shaft 80, the synchronizer 70 and the third gear 90 are fixed on the third shaft 80, the synchronizer 70 is arranged between the first-gear driven gear 61 and the second-gear driven gear 62, the first-gear driving gear 51 is engaged with the first-gear driven gear 61, the second-gear driving gear 52 is engaged with the second-gear driven gear 62, the third gear 90 is connected with the differential 600 through the transmission member 91, and the differential 600 is connected with the left three-axle wheel 700 and the right three-axle wheel 800 through two half shafts.

[0044] In this way, the three-axle transmission mechanism 1000 adopts a relatively simple parallel shaft type gear shifting mechanism, occupies a small volume, has low cost, is convenient to assemble, and has high transmission precision and efficiency.

[0045] The power flow is: the first shaft 10-the first gear 20-the second gear 30-the second shaft 40-the first-gear driving gear 51+the second-gear driving gear 52-the first-gear driven gear 61+the second-gear driven gear 62-the synchronizer 70-the third shaft 80-the third gear 90-the transmission member 91-the differential 600-the left and right half shafts-the left three-axle wheel 700+the right three-axle wheel 800. When the vehicle is in the first gear, the synchronizer 70 is combined with the first-gear driven gear 61; when the vehicle is in the second gear, the synchronizer 70 is combined with the second-gear driven gear 62.

[0046] In the embodiment of the present application, as shown in Figure 1 The left two-axle transmission mechanism 2000 and the right two-axle transmission mechanism 3000 have the same structure and both include two gears engaged with each other.

[0047] In the embodiment of the present application, the controller 900 pre-stores a predetermined high-speed limit value; when the actual vehicle speed is greater than the predetermined high-speed limit value, the controller 900 controls the three-axle motor 500 to start and controls the left two-axle motor 100 and the right two-axle motor 200 to be closed.

[0048] As described above, the electric drive axle control system of the present application can independently control the driving torque of the left two-axle motor 100 and the right two-axle motor 200 respectively to realize independent control of the left and right side driving torques; and when the vehicle is running at high speed, the controller 900 only controls the three-axle motor 500 to start, so that the vehicle can also avoid excessive wear of the tires when running at high speed on a curve. That is, the electric drive axle control system of the present application can not only realize independent control of the left and right wheel torques in special working conditions, but also ensure that the left and right wheel speed differences are reasonably matched to prevent excessive wear of the tires when running at high speed on a curve.

[0049] Based on the above electric drive axle control system, the electric drive axle control system of the application includes control modes in different working states, so that the system has the whole vehicle vector control capability. The system specifically has the following working modes:

[0050] Normal starting mode:

[0051] The controller 900 pre-stores a first threshold value, and the controller 900 can determine the target acceleration a of the whole vehicle according to the whole vehicle throttle input t . When the whole vehicle starts, the controller 900 controls the three-axle motor 500 to start, and when the difference between the target acceleration a of the whole vehicle a t and the actual acceleration a of the whole vehicle a v exceeds the first threshold value, the controller 900 controls the left two-axle motor 100 and the right two-axle motor 200 to start, until the actual acceleration a of the whole vehicle a v reaches the target acceleration a of the whole vehicle a t , the controller 900 controls the left two-axle motor 100 and the right two-axle motor 200 to be closed.

[0052] Specifically, in the normal starting stage, the three-axle motor 500 is preferentially used for starting, and the two-axle is in a follow-up idling mode. The controller 900 determines the target acceleration a of the whole vehicle a t according to the driver's throttle (the characteristic can be calibrated), and adjusts the driving torque of the three-axle motor 500 in combination with the actual acceleration a of the vehicle a v (calculated by vehicle speed) to make the vehicle accelerate according to the expected acceleration; when the integral of the difference between a t and a v exceeds the first threshold value A, it is considered that the driving capability of the three-axle motor 500 is insufficient to make the vehicle accelerate according to the driver's expectation, and then the left two-axle motor 100 and the right two-axle motor 200 are controlled to input driving torque on the basis of the three-axle motor 500 to drive the vehicle to accelerate, so as to improve the vehicle acceleration performance and make it reach the target acceleration a t .

[0053] TCS working mode:

[0054] The controller 900 pre-stores a set value V th and a predetermined ideal vehicle speed value, and the controller 900 can determine the corresponding vehicle speed V 3L according to the wheel speed of the left three-axle wheel 700, determine the corresponding vehicle speed V 3R according to the wheel speed of the right three-axle wheel 800, and determine the corresponding vehicle speed V fa according to the wheel speed of the left one-axle wheel and the right one-axle wheel. When the whole vehicle starts, if (V 3L +V 3R ) / 2-V fa >V th, the TCS system is started, and the controller 900 controls the left two-axle motor 100 and the right two-axle motor 200 to start, and the three-axle motor 500 is closed. During the operation of the left two-axle motor 100 and the right two-axle motor, the controller 900 controls the driving torque of the left two-axle motor 100 and the right two-axle motor respectively, so that the wheel speed of the left two-axle wheel 300 and the right two-axle wheel 400 corresponds to the vehicle speed reaching the predetermined ideal vehicle speed value.

[0055] Specifically, the TCS working mode. When starting to slip, the TCS system needs to intervene, for the three-axle with differential, it is easy to appear one side wheel slip, thereby limiting the torque to play the phenomenon (in the most typical open road, in fact, in the low adhesion road, due to the small difference of the left and right wheel road adhesion coefficient, it is also easy to appear one side wheel slip phenomenon). At this time, for the three-axle with differential, only by applying brake to the slipping side wheel to increase the actual torque that can be reached (BTC function in TCS).

[0056] To solve the above problems, in this case (when TCS is activated), the two-axle drive is preferred to start. The left two-axle motor 100 and the right two-axle motor can independently output driving force under the control of the controller 900 (ECU) according to their respective working states, avoiding the influence of the differential 600, so that the maximum ground adhesion of each wheel can be exerted on various road surfaces (including open road and low adhesion road), providing the maximum driving torque and obtaining the best starting ability. The specific working process is as follows:

[0057] 1. At the beginning of starting, the system is in the normal starting state in the (normal starting mode). During the starting process, the vehicle speed V 3L , V 3R and the average value V fa of the wheel speed of the left and right one-axle wheels are detected in real time. 3L -V 3R ) / 2-V fa exceeds the set value V th (Vt h can be calibrated as a fixed value or a value related to the actual vehicle speed), it is indicated that the driving wheel has excessive slip compared with the vehicle, and the TCS system driving anti-slip function is activated. At this time, in order to better control the TCS function, the driving function is gradually transferred from the normal three-axle to the two-axle, and the two-axle takes over the whole vehicle driving task.

[0058] 2. During the above switching process, based on the torque T0 of the three-axle motor 500 at the time when the TCS function is activated, the torque of the three-axle motor 500 is gradually reduced by a gradient ΔT (which can be calibrated according to the actual situation): T4 = T0-ΔT t, where t is the time from the TCS function activation to the present moment. The torque of the left two-axle motor 100 and the right two-axle motor 200 is gradually increased by a gradient ΔT (which can be calibrated according to actual conditions): T1 = T0 + ΔT t , and is evenly distributed between the left two-axle motor 100 and the right two-axle motor 200. In this way, the driving torque can be gradually transitioned from three-axle to two-axle, facilitating subsequent control.

[0059] 3. After the driving torque is transitioned to two-axle, since the left two-axle motor 100 and the right two-axle motor 200 of the two-axle are independent of each other, they can be independently controlled, so in the subsequent driving process, the driving torque of the left two-axle motor 100 and the right two-axle motor 200 can be controlled according to the rotational speed of the left two-axle wheel 300 and the right two-axle wheel 400 of the two-axle, respectively, to achieve the best control effect. The ideal driving slip rate for acceleration is (which can be 15%, and the specific value can be calibrated according to the actual vehicle parameters), so the predetermined ideal vehicle speed value V t of the left two-axle wheel 300 and the right two-axle wheel 400 of the two-axle is fa . The controller 900 monitors the vehicle speed V 2L , V 2R corresponding to the rotational speed of the left two-axle wheel 300 and the right two-axle wheel 400, takes V t as the target value, and adjusts the driving torque of the two motors in real time through closed-loop control (which can be through PID algorithm), so that the left two-axle motor 100 and the right two-axle motor 200 are maintained in the ideal driving slip rate working interval, achieving the best acceleration capability.

[0060] High-speed driving mode:

[0061] The controller 900 has a predetermined high-speed limit value stored in advance, and when the actual vehicle speed of the vehicle is greater than the predetermined high-speed limit value, the controller 900 controls the three-axle motor 500 to start and controls the left two-axle motor 100 and the right two-axle motor 200 to be closed.

[0062] Specifically, the high-speed driving mode. When driving at high speed, in order to reduce the error caused by independent control of the left and right wheel speeds when turning, which causes excessive wear of the tires, in this mode, the three-axle is preferentially used for driving. At this time, the differential 600 of the three-axle can automatically differentially the left and right wheels according to the turning radius, thereby achieving the minimum wear of the tires. The specific implementation method is that when it is judged that the vehicle speed is greater than the predetermined high-speed limit value (threshold value V th2When the speed is generally 40km / h, if the vehicle was previously in the normal start mode, the TCS working mode will be disabled and the three-axle drive will be maintained. If the vehicle was previously in the TCS working mode, it will be driven by the second axle. After entering the high-speed driving mode, the torque of the second axle motor (referring to the sum of the torques of the left second axle motor 100 and the right second axle motor 200) will be transferred to the third axle according to the torque gradient method of the TCS working mode. After that, the vehicle will be driven by the third axle. When maintaining high speed, the differential 600 will be used to ensure that the tires on both sides do not experience excessive wear when driving in corners.

[0063] Energy recovery mode:

[0064] The controller 900 has a second threshold value pre-stored, and the controller 900 can determine the desired yaw rate w based on the steering wheel input. t When the three-axle motor recovers energy at 500 rpm, the actual yaw rate of the vehicle is w. z The expected yaw rate w of the whole vehicle t When the difference exceeds the second threshold, the controller 900 controls the left second axle motor 100 or the right second axle motor 200 to start until the actual yaw rate of the vehicle w. z The desired yaw rate w of the whole vehicle t The controller 900 controls the left second axle motor 100 or the right second axle motor 200 to shut down. When the third axle motor 500 is recovering energy, the actual yaw rate of the vehicle is w... z The expected yaw rate w of the whole vehicle t When the difference is positive, controller 900 increases the regenerative braking torque of the right second axle motor 200, when the actual yaw rate of the vehicle is w z The expected yaw rate w of the whole vehicle t When the difference is negative, the controller 900 increases the regenerative braking torque of the left second axle motor 100.

[0065] Specifically, in the energy recovery mode, during energy recovery, the third-axle motor 500 (the central motor of the third axle) is prioritized to recover braking energy, ensuring that the regenerative braking force on the left and right sides is equal, which is beneficial for maintaining directional stability. When the vehicle yaws slightly due to steering, road conditions, or other factors, regenerative braking of the corresponding wheels on the second axle intervenes to adjust the vehicle's posture and keep the vehicle traveling in the desired direction. The specific implementation method is as follows: during energy recovery on the third axle, if the actual yaw rate w... z (Measured by the IMU set in controller 900) and the driver's desired yaw rate w t(Calculated based on the driver's steering wheel angle input and the Ackermann formula, details omitted here) When the deviation between the input and the second threshold value is greater than the second threshold, it indicates that the actual steering of the vehicle body is inconsistent with the driver's expected steering. Compensation can be achieved by controlling the regenerative braking torque of the single-sided wheel of the second axle. Specifically, when w z -w t When the value is positive (with leftward / counterclockwise rotation as positive), the regenerative braking torque of the right second axle motor 200 is increased; conversely, when w is negative... z -w t When the value is negative, the regenerative braking torque of the left second axle motor is increased by 100. The specific increase can be achieved through closed-loop control using PID or other methods, or through open-loop adjustment using a fixed gradient increase.

[0066] Wheel-end vector control mode:

[0067] The controller 900 can determine the desired yaw rate w based on the steering wheel input. t When the vehicle turns left, the actual yaw rate of the vehicle is w z The expected yaw rate w of the whole vehicle t When the difference is positive, controller 900 increases the drive torque of the left second axle motor 100; when the actual yaw rate of the vehicle is w z The expected yaw rate w of the whole vehicle t When the difference is negative, controller 900 increases the drive torque of the right second axle motor 200. When the vehicle turns right, when the actual yaw rate w of the vehicle... z The expected yaw rate w of the whole vehicle t When the difference is positive, the controller 900 increases the drive torque of the right second axle motor 200; when the actual yaw rate of the vehicle is w z The expected yaw rate w of the whole vehicle t When the difference is negative, the controller 900 increases the drive torque of the left second axle motor 100.

[0068] Specifically, this involves wheel-end vector control. In this mode, the system can generate a certain yaw moment on the vehicle by individually controlling the torque of the left second axle motor 100 or the right second axle motor 200, thereby achieving some functions of assisting vehicle stability through drive. For example, when understeer occurs, a system without wheel-end vector control can only assist in yaw control by applying braking to the inner front or rear wheels. However, this system can also correct understeer by controlling the drive torque of the outer wheels of the second axle. For oversteer conditions, active yaw control can also be achieved by applying driving force to the inner drive wheels of the second axle.

[0069] Split-road braking mode:

[0070] The controller 900 can determine the corresponding wheel slip ratio according to the wheel speed of the left front axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the right front axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the left rear axle wheel 300, determine the corresponding wheel slip ratio according to the wheel speed of the right rear axle wheel 400, determine the corresponding wheel slip ratio according to the wheel speed of the left rear axle wheel 700, and determine the corresponding wheel slip ratio according to the wheel speed of the right rear axle wheel 800. When the vehicle brakes on the split road surface, if the wheel slip ratio of the left front axle wheel is greater than that of the right front axle wheel, the wheel slip ratio of the left rear axle wheel 300 is greater than that of the right rear axle wheel 400, and the wheel slip ratio of the left rear axle wheel 700 is greater than that of the right rear axle wheel 800, the controller 900 controls the left front axle wheel, the right front axle wheel, the left rear axle wheel 300, the left rear axle wheel 700 and the right rear axle wheel 800 to brake, and controls the torque of the right rear axle motor 200 to make the right rear axle wheel 400 generate driving force Ft. Conversely, when the vehicle brakes on the split road surface, if the wheel slip ratio of the left front axle wheel is less than that of the right front axle wheel, the wheel slip ratio of the left rear axle wheel 300 is less than that of the right rear axle wheel 400, and the wheel slip ratio of the left rear axle wheel 700 is less than that of the right rear axle wheel 800, the controller 900 controls the left front axle wheel, the right front axle wheel, the right rear axle wheel 400, the left rear axle wheel 700 and the right rear axle wheel 800 to brake, and controls the torque of the left rear axle motor 100 to make the left rear axle wheel 300 generate driving force Ft.

[0071] Specifically, when braking on the split road surface, under normal circumstances, the high-attached side braking force is much greater than the low-attached side, thereby generating a torque to the high-attached side of the vehicle, causing the directional stability to be difficult to maintain. In this working condition, the high-attached side of the second axle is not braked, and the other wheels are normally braked, and a driving torque is applied to the high-attached side wheel of the second axle to generate a lateral yaw torque to offset the lateral yaw torque generated by the unbalanced braking force, thereby assisting in maintaining the directional stability of the vehicle, thereby improving both the braking intensity and the directional stability. The specific implementation method is as follows: during braking, the wheel slip ratio (the percentage of the difference between the corresponding wheel speed and the reference speed, wherein the reference speed can be calculated by integral method, wheel speed vertex method, etc., which is not the content of the present application and will not be described in detail) of each wheel is monitored in real time. If the wheel slip ratios of the left wheels of the first, second and third axles are all greater than those of the right wheels, it indicates that the current road condition is left low and right high (the left side is low-attached and the right side is high-attached). At this time, since the right side braking force is greater than the left side, the vehicle will deflect to the right side. At this time, the right rear axle wheel 400 is no longer subjected to braking force, but generates a certain driving force Ft t to offset the right deflection of the vehicle. t The specific value of F zAs close to 0 as possible, which can be achieved by a PID algorithm or a lookup table, etc.

[0072] According to the second aspect of the application, a commercial vehicle is provided, which comprises the electric drive axle control system as described above.

[0073] In summary, the application provides an electric drive axle control system to meet the torque vectoring control requirements of an intelligent chassis of a commercial vehicle. The electric drive axle control system can independently control the driving torque of the left two-axle motor 100 and the right two-axle motor 200, respectively, to achieve independent control of the driving torque of the left and right sides. Moreover, when the vehicle is running at high speed, the controller 900 only controls the three-axle motor 500 to start, so that the vehicle can avoid excessive wear of the tires when driving on a high-speed curve. That is, the electric drive axle control system of the application can not only achieve independent control of the left and right wheel torques in special working conditions, but also ensure that the left and right wheel speed differences are reasonably coordinated to prevent excessive wear of the tires when driving at high speed, thus meeting the control requirements of an intelligent chassis.

[0074] Finally, it should be noted that the above-described embodiments are merely specific implementations of the application, which are used to illustrate the technical solutions of the application, but not to limit the same. The protection scope of the application is not limited thereto, although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily think of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed by the application, or make equivalent replacements to some technical features thereof; and these modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application, and should be covered within the protection scope of the application.

Claims

1. An electric drive axle control system, characterized in that The electric drive axle control system comprises a left two-axle motor, a right two-axle motor, a left two-axle wheel, a right two-axle wheel, a left two-axle transmission mechanism, a right two-axle transmission mechanism, a three-axle motor, a differential, a left three-axle wheel, a right three-axle wheel, a three-axle transmission mechanism, and a controller; The left two-axle motor is connected to the left two-axle wheel through the left two-axle transmission mechanism, the right two-axle motor is connected to the right two-axle wheel through the right two-axle transmission mechanism, and the controller can control the driving torque of the left two-axle motor and the right two-axle motor, respectively; The three-axle motor is connected to the differential through the three-axle transmission mechanism, and the differential is connected to the left three-axle wheel and the right three-axle wheel, respectively; The controller pre-stores a predetermined high-speed limit value; When the actual vehicle speed is greater than the predetermined high-speed limit value, the controller controls the three-axle motor to start and controls the left two-axle motor and the right two-axle motor to stop; The controller is able to determine a desired yaw rate w from the steering wheel input t ; When the difference between the actual yaw rate w z of the vehicle and the desired yaw rate w t of the vehicle is positive, the controller increases the driving torque of the left two-axle motor; when the difference between the actual yaw rate w z of the vehicle and the desired yaw rate w t of the vehicle is negative, the controller increases the driving torque of the right two-axle motor; When the difference between the actual yaw rate w z of the vehicle and the desired yaw rate w t of the vehicle is positive, the controller increases the driving torque of the right two-axle motor; when the difference between the actual yaw rate w z of the vehicle and the desired yaw rate w t of the vehicle is negative, the controller increases the driving torque of the left two-axle motor.

2. The electric drive axle control system of claim 1, wherein, The controller pre-stores a first threshold value, and the controller can determine a target acceleration a of the vehicle according to an accelerator input of the vehicle t ; When the whole vehicle starts, the controller controls the three-axle motor to start, when the difference between the target acceleration a t of the whole vehicle and the actual acceleration a v of the whole vehicle exceeds the first threshold value, the controller controls the left two-axle motor and the right two-axle motor to start, until the actual acceleration a v of the whole vehicle reaches the target acceleration a t of the whole vehicle, the controller controls the left two-axle motor and the right two-axle motor to be closed.

3. The electric drive axle control system of claim 2, wherein, The electric drive axle control system further comprises a left one-axle wheel, a right one-axle wheel, and a TCS system; The controller pre-stores a set value V th and a predetermined ideal vehicle speed value, and can determine a corresponding vehicle speed V 3L according to the wheel speed of the left three-axle wheels, 3R according to the wheel speed of the right three-axle wheels, and fa according to the wheel speed of the left and right single-axle wheels. If (V 3L +V 3R ) / 2-V fa >V th , the TCS system is started, the controller controls the left two-axle motor and the right two-axle motor to start, and the three-axle motor is closed; During the operation of the left two-axle motor and the right two-axle motor, the controller controls the driving torque of the left two-axle motor and the right two-axle motor, respectively, so that the vehicle speed corresponding to the wheel speed of the left two-axle wheel and the right two-axle wheel reaches the predetermined ideal vehicle speed value.

4. The electric drive axle control system of claim 3, wherein, the predetermined ideal vehicle speed value V t = (1 + S) V fa where S is the drive slip ratio. When the wheel speeds of the left two-axle wheels and the right two-axle wheels of the whole vehicle correspond to a vehicle speed of the predetermined ideal vehicle speed value V t , the controller controls the three-axle motor to start and controls the left two-axle motor and the right two-axle motor to stop.

5. The electric drive axle control system of claim 1, wherein, The controller pre-stores a second threshold value, and the controller can determine the desired yaw rate w t , When the three-axle motor recovers energy, when the actual yaw rate w z of the whole vehicle exceeds the second threshold value from the expected yaw rate w t of the whole vehicle, the controller controls the left two-axle motor or the right two-axle motor to start until the actual yaw rate w z of the whole vehicle reaches the expected yaw rate w t of the whole vehicle, and the controller controls the left two-axle motor or the right two-axle motor to stop.

6. The electric drive axle control system of claim 5, wherein, When the three-axle motor recovers energy, when the difference between the actual yaw rate w z of the vehicle and the expected yaw rate w t of the vehicle is positive, the controller increases the regenerative braking torque of the right two-axle motor. When the actual yaw rate w z the difference between the desired yaw rate w t of the vehicle is negative, the controller increases the regenerative braking torque of the left two-axle motor.

7. The electric drive axle control system of claim 3, wherein, The controller can determine the corresponding wheel slip ratio according to the wheel speed of the left one-axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the right one-axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the left two-axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the right two-axle wheel, determine the corresponding wheel slip ratio according to the wheel speed of the left three-axle wheel, and determine the corresponding wheel slip ratio according to the wheel speed of the right three-axle wheel; When the vehicle brakes on a split road surface, if the wheel slip ratio of the left one-axle wheel is greater than the wheel slip ratio of the right one-axle wheel, the wheel slip ratio of the left two-axle wheel is greater than the wheel slip ratio of the right two-axle wheel, and the wheel slip ratio of the left three-axle wheel is greater than the wheel slip ratio of the right three-axle wheel, the controller controls the left one-axle wheel, the right one-axle wheel, the left two-axle wheel, the left three-axle wheel, and the right three-axle wheel to brake, and controls the torque of the right two-axle motor so that the right two-axle wheel generates driving force; When the vehicle brakes on a split road surface, if the wheel slip ratio of the left one-axle wheel is less than the wheel slip ratio of the right one-axle wheel, the wheel slip ratio of the left two-axle wheel is less than the wheel slip ratio of the right two-axle wheel, and the wheel slip ratio of the left three-axle wheel is less than the wheel slip ratio of the right three-axle wheel, the controller controls the left one-axle wheel, the right one-axle wheel, the right two-axle wheel, the left three-axle wheel, and the right three-axle wheel to brake, and controls the torque of the left two-axle motor so that the left two-axle wheel generates driving force.

8. The electric drive axle control system according to any one of claims 1-7, characterized by, The three-axle transmission mechanism comprises a first shaft, a first gear, a second gear, a second shaft, a first-gear driving gear, a second-gear driving gear, a third shaft, a first-gear driven gear, a second-gear driven gear, a synchronizer, a third gear, and a transmission member; The three-axle motor is connected with the first gear through the first shaft, the first gear is engaged with the second gear, the second gear, the first-gear drive gear and the second-gear drive gear are fixed on the second shaft, the first-gear driven gear and the second-gear driven gear are sleeved on the third shaft, the synchronizer and the third gear are fixed on the third shaft, the synchronizer is arranged between the first-gear driven gear and the second-gear driven gear, the first-gear drive gear is engaged with the first-gear driven gear, the second-gear drive gear is engaged with the second-gear driven gear, the third gear is connected with the differential through the transmission part, and the differential is connected with the left three-axle wheel and the right three-axle wheel through two half shafts.

9. A commercial vehicle characterized in that An electric drive axle control system as claimed in any one of claims 1-8.

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