A control method and system for improving vehicle trafficability
By automatically identifying the vehicle's slipping state and distributing the front and rear axle torque, the problem that traditional vehicles cannot accurately control the torque distribution when the wheels are slipping is solved, and the vehicle's easy escape on ice and snowy roads and the vehicle's passing ability is improved, reducing driving Staff operation requirements and vehicle costs.
Patent Information
- Application Number
- CN202110002347.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-01-04
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2041-01-04
AI Technical Summary
When traditional fuel vehicles and electric vehicles encounter wheel slippage, they cannot accurately control the torque distribution, resulting in the inability to exert their vehicle's ability to pass, especially on ice and snowy roads.
It provides a control method for improving the passing of the vehicle. By obtaining the vehicle speed and wheel speed, it automatically recognizes the current slipping state, and distributes the front and rear axle torque according to the target torque of the vehicle to improve the passing of the vehicle. The method includes determining the slipping state of the vehicle when the vehicle speed is greater than or equal to the preset threshold value, and distributing torque according to different slipping states to ensure that the vehicle can easily get out of trouble.
It realizes automatic identification and correction of the vehicle's slipping state, avoids the driver's need for manual control, improves the vehicle's vehicle's passing ability and escape ability, reduces the driver's operating requirements, and avoids stable body control under small torque requirements. The system reduces the driving torque of the sliding wheels, maintaining the steering and driving comfort of the vehicle.
Smart Images
Figure CN114714918B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of automobile braking, and in particular to a control method and system for improving the trafficability of a whole vehicle. Background Art
[0002] Most of the four-wheel drive systems of traditional fuel vehicles use an intelligent torque distribution transmission system. This system can only distribute the torque of the front and rear axles at discrete proportional points, and when a single-axle wheel slips, the torque distribution cannot be accurately controlled, making it easy for the other wheel to slip, resulting in the inability to fully utilize the vehicle's passing ability. In order to improve the vehicle's passing ability, a common method for traditional fuel vehicles is to add a differential lock device on a single axle and between axles, but this method requires the driver to manually set it on and off, which not only requires high skills from the driver, but also greatly increases the cost of the vehicle and the complexity of the design. However, even if the driver of a traditional fuel vehicle has high driving skills, the torque distribution system cannot accurately distribute the torque of the front and rear axles, and the front wheel slips or the front and rear wheels slip at the same time on icy and snowy roads and cannot get out of trouble.
[0003] For electric vehicles with split-axle dual-motor drive systems, there is no treatment measure for single-axle slippage. When wheel slippage occurs, the body stability control system (ESP) is used to reduce the torque of the axle where the slipping wheel is located. However, this part of the reduced torque will be lost, making it impossible for the vehicle to exert its full vehicle passing ability, and even the single-axle wheel or dual-axle wheel will continue to slip and cannot get out of trouble (especially for electric vehicles driven by a single motor).
[0004] Therefore, there is an urgent need to provide a control method for improving the vehicle's passability, which can replace the driver's precise control through technical means to redistribute the front and rear axle torque, so as to achieve the purpose of easily getting the vehicle out of trouble. Summary of the invention
[0005] The technical problem to be solved by the embodiments of the present invention is to provide a control method and system for improving the passability of the entire vehicle, which can replace the driver's precise control through technical means to redistribute the front and rear axle torque, thereby achieving the purpose of easily getting the vehicle out of trouble and improving the vehicle's passability.
[0006] In order to solve the above technical problems, an embodiment of the present invention provides a control method for improving vehicle trafficability, which is used in a vehicle with a split-axle dual-motor four-wheel drive system. The method includes the following steps:
[0007] Get the vehicle speed and four wheel speeds;
[0008] If the vehicle speed is greater than or equal to the preset vehicle speed threshold value, the current slip state of the vehicle is determined according to the wheel speeds of the four wheels; wherein the current slip state of the vehicle is one of at least one wheel slipping on the front axle and no wheel slipping on the rear axle, at least one wheel slipping on the rear axle and no wheel slipping on the front axle, wheel slipping on both the front and rear axles, and frequent alternating slipping of the wheels on the front and rear axles;
[0009] Obtaining the accelerator pedal depth and combining it with the vehicle speed to obtain the vehicle target required torque;
[0010] According to the current slip state of the vehicle, the target required torque of the whole vehicle is distributed to the front and rear axle torques to improve the passability of the whole vehicle.
[0011] The step of distributing the target required torque of the vehicle to the front and rear axle torques according to the current slip state of the vehicle to improve the passability of the vehicle specifically includes:
[0012] When the current slip state of the vehicle is that at least one wheel on the front axle slips but no wheel on the rear axle slips, if it is determined that the target required torque of the whole vehicle is greater than a first preset torque threshold value, the target required torque of the whole vehicle is distributed to the front and rear axle torques according to a first distribution ratio pre-formed between the front axle torque and the rear axle torque; or
[0013] If it is determined that the vehicle target demand torque is less than or equal to the first preset torque threshold value, the vehicle target demand torque is first distributed to the rear axle torque according to the preset first upper limit value, and then the remaining torque is distributed to the front axle torque.
[0014] The step of distributing the target required torque of the vehicle to the front and rear axle torques according to the current slip state of the vehicle to improve the passability of the vehicle further specifically includes:
[0015] When the current slip state of the vehicle is that at least one wheel on the rear axle slips but no wheel on the front axle slips, if it is determined that the target required torque of the whole vehicle is greater than a second preset torque threshold value, the target required torque of the whole vehicle is distributed to the front and rear axle torques according to a second distribution ratio pre-formed between the front axle torque and the rear axle torque; or
[0016] If it is determined that the vehicle target demand torque is less than or equal to the second preset torque threshold value, the vehicle target demand torque is first distributed to the front axle torque according to the preset second upper limit value, and then the remaining torque is distributed to the rear axle torque.
[0017] The step of distributing the target required torque of the vehicle to the front and rear axle torques according to the current slip state of the vehicle to improve the passability of the vehicle further includes:
[0018] When the current slip state of the vehicle is that wheels slip simultaneously on the front and rear axles, if it is determined that the target required torque of the whole vehicle is greater than a third preset torque threshold value, the target required torque of the whole vehicle is distributed to the front and rear axle torques according to a third distribution ratio pre-formed between the front axle torque and the rear axle torque; or
[0019] If it is determined that the vehicle target demand torque is less than or equal to the third preset torque threshold value, the vehicle target demand torque is distributed to the front and rear axle torques according to a fourth distribution ratio pre-formed between the front axle torque and the rear axle torque.
[0020] The step of distributing the target required torque of the vehicle to the front and rear axle torques according to the current slip state of the vehicle to improve the passability of the vehicle further includes:
[0021] When the current slipping state of the vehicle is that the front and rear axle wheels slip frequently and alternately, if it is determined that the whole vehicle target demand torque is greater than a fourth preset torque threshold value, the whole vehicle target demand torque is distributed to the front and rear axle torques according to a fifth distribution ratio pre-formed between the front axle torque and the rear axle torque; or
[0022] If it is determined that the vehicle target demand torque is less than or equal to the fourth preset torque threshold value, the vehicle target demand torque is distributed to the front and rear axle torques according to a sixth distribution ratio pre-formed between the front axle torque and the rear axle torque.
[0023] The embodiment of the present invention also provides a control system for improving vehicle trafficability, which is used in a vehicle with a split-axle dual-motor four-wheel drive system, and includes a vehicle speed and wheel speed acquisition unit, a slip state determination unit, a target demand torque calculation unit, and a front and rear axle torque distribution unit; wherein,
[0024] The vehicle speed and wheel speed acquisition unit is used to acquire the vehicle speed and the wheel speeds of the four wheels;
[0025] The slip state determination unit is used to determine the current slip state of the vehicle according to the wheel speeds of the four wheels if the vehicle speed is greater than or equal to a preset vehicle speed threshold value; wherein the current slip state of the vehicle is one of at least one wheel slipping on the front axle and no wheel slipping on the rear axle, at least one wheel slipping on the rear axle and no wheel slipping on the front axle, simultaneous wheel slipping on the front and rear axles, and frequent alternating slipping of the wheels on the front and rear axles;
[0026] The target required torque calculation unit is used to obtain the accelerator pedal depth and, in combination with the vehicle speed, obtain the vehicle's entire vehicle target required torque;
[0027] The front and rear axle torque distribution unit is used to distribute the target required torque of the whole vehicle to the front and rear axle torque according to the current slip state of the vehicle, so as to improve the passability of the whole vehicle.
[0028] Wherein, the front and rear axle torque distribution unit comprises:
[0029] A first torque distribution module is used for distributing the target torque of the whole vehicle to the front and rear axle torques according to a first distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slip state of the vehicle is that at least one wheel of the front axle slips and no wheel of the rear axle slips, if it is determined that the target torque required by the whole vehicle is greater than a first preset torque threshold value; or
[0030] If it is determined that the vehicle target demand torque is less than or equal to the first preset torque threshold value, the vehicle target demand torque is first distributed to the rear axle torque according to the preset first upper limit value, and then the remaining torque is distributed to the front axle torque.
[0031] Wherein, the front and rear axle torque distribution unit further includes:
[0032] A second torque distribution module is used for distributing the target torque of the whole vehicle to the front and rear axle torques according to a second distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slip state of the vehicle is that at least one wheel of the rear axle slips and no wheel of the front axle slips, if it is determined that the target torque required for the whole vehicle is greater than a second preset torque threshold value; or
[0033] If it is determined that the vehicle target demand torque is less than or equal to the second preset torque threshold value, the vehicle target demand torque is first distributed to the front axle torque according to the preset second upper limit value, and then the remaining torque is distributed to the rear axle torque.
[0034] Wherein, the front and rear axle torque distribution unit further includes:
[0035] A third torque distribution module is used for distributing the target torque of the whole vehicle to the front and rear axles according to a third distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slip state of the vehicle is that the wheels of the front and rear axles slip at the same time, if it is determined that the target torque required by the whole vehicle is greater than a third preset torque threshold value; or
[0036] If it is determined that the vehicle target demand torque is less than or equal to the third preset torque threshold value, the vehicle target demand torque is distributed to the front and rear axle torques according to a fourth distribution ratio pre-formed between the front axle torque and the rear axle torque.
[0037] Wherein, the front and rear axle torque distribution unit further includes:
[0038] a fourth torque distribution module, configured to distribute the target torque of the vehicle to the front and rear axle torques according to a fifth distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slipping state of the vehicle is that the front and rear axle wheels slip frequently and alternately, if it is determined that the target torque required for the whole vehicle is greater than a fourth preset torque threshold value; or
[0039] If it is determined that the vehicle target demand torque is less than or equal to the fourth preset torque threshold value, the vehicle target demand torque is distributed to the front and rear axle torques according to a sixth distribution ratio pre-formed between the front axle torque and the rear axle torque.
[0040] Implementing the embodiments of the present invention has the following beneficial effects:
[0041] 1. The present invention realizes automatic identification of the current slipping state of the vehicle for correction of the required torque of the whole vehicle, avoiding the problem that the driver chooses whether to turn on the passability improvement function according to his own cognition, greatly improving the applicability of the function, so that the front and rear axle torques can be redistributed by technical means instead of the driver's precise control, so as to achieve the purpose of making the vehicle easily get out of trouble;
[0042] 2. The present invention can correct the torque redistribution under small torque demand, and will avoid the direct loss of the driving torque reduction of the axle where the slipping wheel is located by the vehicle stability control system ESP as much as possible, without obvious influence on the steering performance and driving comfort of the vehicle;
[0043] 3. The present invention can achieve vehicle escape based on a small throttle, which reduces the driver's operating requirements and has strong adaptability;
[0044] 4. The present invention does not require any additional hardware, and will not increase the cost of the vehicle or the design complexity of the transmission system. BRIEF DESCRIPTION OF THE DRAWINGS
[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.
[0046] Figure 1 A flow chart of a control method for improving vehicle trafficability provided by an embodiment of the present invention;
[0047] Figure 2 A schematic structural diagram of a control system for improving vehicle trafficability provided by an embodiment of the present invention. DETAILED DESCRIPTION
[0048] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.
[0049] like Figure 1 As shown in the figure, a control method for improving the vehicle trafficability is provided in an embodiment of the present invention, and the method comprises the following steps:
[0050] Step S1, obtaining the vehicle speed and the four wheel speeds;
[0051] The specific process is to detect the wheel speeds of the four wheels through sensors and report them to the vehicle control unit (VCU) in real time through the ESP system. The vehicle controller calculates the vehicle's center of mass speed based on other parameters.
[0052] It is understandable that in order to ensure the validity of the collected data to realize the identification of subsequent slip conditions and torque redistribution, the VCU will detect the validity of the vehicle speed and wheel speed (such as signal validity detection or reference to ESP's determination of the validity of the original signal of wheel speed detection), and discard invalid data such as invalid vehicle speed and the wheel speed of the four wheels that do not meet the requirements.
[0053] Step S2, if the vehicle speed is greater than or equal to the preset vehicle speed threshold value, determining the current slip state of the vehicle according to the wheel speeds of the four wheels; wherein the current slip state of the vehicle is one of at least one wheel slipping on the front axle and no wheel slipping on the rear axle, at least one wheel slipping on the rear axle and no wheel slipping on the front axle, simultaneous wheel slipping on the front and rear axles, and frequent alternating slipping of the wheels on the front and rear axles;
[0054] The specific process is to determine whether to activate the torque ratio correction function for improving passability (i.e., redistribute the front and rear axle torque) based on the vehicle speed and the preset speed threshold (e.g., 20m / s); once the vehicle speed is greater than or equal to the preset speed threshold, it is activated; and if the vehicle speed is lower than the preset speed threshold, it is not activated (i.e., the front and rear axle torque is not redistributed). Of course, if the vehicle speed is invalid, it is not activated either.
[0055] At this time, based on the activation of the torque ratio correction function for improving passability, the vehicle's current slip state is obtained according to the judgment conditions of the four wheel speeds (such as determining that a wheel is slipping when its slip rate is higher than a certain value, and the certain value set for the front and rear wheels can be the same or different), which specifically includes the following four types: at least one wheel on the front axle slips but no wheel on the rear axle, at least one wheel on the rear axle slips but no wheel on the front axle, wheel slips on both the front and rear axles, and the front and rear axles frequently slip alternately.
[0056] It is understandable that the above four slip states are indicated by the activation states of different flags, for example, the front wheel flag FTCS and the rear wheel flag RTCS are set to indicate that when at least one front wheel slips, the activation state of FTCS is set to 1; when at least one rear wheel slips, the activation state of RTCS is set to 1.
[0057] Therefore, at least one wheel slipping on the front axle while no wheel slipping on the rear axle can be represented by FTCS being activated and set to 1, and RTCS being inactivated and set to 0; at least one wheel slipping on the rear axle while no wheel slipping on the front axle can be represented by FTCS being inactivated and set to 0, and RTCS being activated and set to 1; simultaneous wheel slipping on the front and rear axles can be represented by both FTCS and RTCS being activated and set to 1; frequent alternating slipping of the front and rear axle wheels can be represented by FTCS and RTCS being alternately activated within a certain time window (such as 2S to 3S), and the number of transitions between 0 and 1 exceeding a preset number (such as 3 times).
[0058] Step S3, obtaining the accelerator pedal depth, and combining it with the vehicle speed to obtain the vehicle target required torque;
[0059] The specific process is to obtain the accelerator pedal depth (ie, the accelerator pedal opening is greater than a preset value of 0), and to look up the preset driving torque table according to the vehicle speed and the accelerator pedal depth to obtain the target required torque of the whole vehicle.
[0060] Step S4: Distribute the target required torque of the vehicle to the front and rear axle torques according to the current slip state of the vehicle to improve the passability of the vehicle.
[0061] The specific process is to distribute the target required torque of the vehicle accordingly according to the above four slip states, so as to realize the torque correction of the front and rear axles of the vehicle to improve the vehicle's passability, as follows:
[0062] (1) when the current slip state of the vehicle is that at least one wheel on the front axle slips and no wheel on the rear axle slips, if it is determined that the target required torque of the vehicle is greater than a first preset torque threshold value, the target required torque of the vehicle is distributed to the front and rear axle torques according to a first distribution ratio pre-formed between the front axle torque and the rear axle torque; or
[0063] If it is determined that the target required torque of the vehicle is less than or equal to the first preset torque threshold value, the target required torque of the vehicle is first distributed to the rear axle torque according to the preset first upper limit value, and then the remaining torque is distributed to the front axle torque.
[0064] (2) when the current slip state of the vehicle is that at least one wheel on the rear axle slips but no wheel on the front axle slips, if it is determined that the target required torque of the vehicle is greater than a second preset torque threshold value, the target required torque of the vehicle is distributed between the front and rear axle torques according to a second distribution ratio pre-formed between the front axle torque and the rear axle torque; or
[0065] If it is determined that the target required torque of the vehicle is less than or equal to the second preset torque threshold value, the target required torque of the vehicle is first distributed to the front axle torque according to the preset second upper limit value, and then the remaining torque is distributed to the rear axle torque.
[0066] (3) when the current slip state of the vehicle is that wheels slip simultaneously on the front and rear axles, if it is determined that the target required torque of the vehicle is greater than a third preset torque threshold value, the target required torque of the vehicle is distributed to the front and rear axles according to a third distribution ratio pre-formed between the front axle torque and the rear axle torque; or
[0067] If it is determined that the target required torque of the whole vehicle is less than or equal to the third preset torque threshold value, the target required torque of the whole vehicle is distributed to the front and rear axle torques according to a fourth distribution ratio pre-formed between the front axle torque and the rear axle torque.
[0068] (4) when the current slipping state of the vehicle is that the front and rear axle wheels slip frequently and alternately, if it is determined that the target required torque of the whole vehicle is greater than the fourth preset torque threshold value, the target required torque of the whole vehicle is distributed to the front and rear axle torques according to a fifth distribution ratio pre-formed between the front axle torque and the rear axle torque; or
[0069] If it is determined that the target required torque of the whole vehicle is less than or equal to the fourth preset torque threshold value, the target required torque of the whole vehicle is distributed to the front and rear axle torques according to a sixth distribution ratio pre-formed between the front axle torque and the rear axle torque.
[0070] It should be noted that the VCU calibrates the correction value of the basic distribution ratio, including the first upper limit value, the second upper limit value, and the first to sixth distribution ratios, according to the adhesion coefficient of the low-adhesion boundary road surface that the vehicle needs to pass unconditionally, the climbing ability of the low-adhesion road surface, the current driver's target demand torque, the vehicle speed, and the mass of the vehicle. In the application scenario, in order to avoid slipping, the driver often accelerates by stepping on the accelerator pedal; at this time, when the VCU determines that the vehicle speed is higher than the preset speed threshold, it will calculate the vehicle's target demand torque based on the accelerator pedal and the vehicle speed, and further redistribute the vehicle's target demand torque on the front and rear axles according to the vehicle's current slip state, so that the vehicle can quickly get rid of the current slip state and improve the vehicle's passability.
[0071] It should be noted that, in the control method for improving the vehicle's trafficability provided in the embodiment of the present invention, the front axle torque and the rear axle torque are respectively output to the front and rear axle drive motors.
[0072] like Figure 2As shown, a control system for improving vehicle trafficability is provided in an embodiment of the present invention, which is used in a vehicle with a split-axle dual-motor four-wheel drive system, including a vehicle speed and wheel speed acquisition unit 110, a slip state determination unit 120, a target demand torque calculation unit 130 and a front and rear axle torque distribution unit 140; wherein,
[0073] The vehicle speed and wheel speed acquisition unit 110 is used to acquire the vehicle speed and the wheel speeds of the four wheels;
[0074] The slip state determination unit 120 is used to determine the current slip state of the vehicle according to the wheel speeds of the four wheels if the vehicle speed is greater than or equal to a preset vehicle speed threshold value; wherein the current slip state of the vehicle is one of at least one wheel slipping on the front axle and no wheel slipping on the rear axle, at least one wheel slipping on the rear axle and no wheel slipping on the front axle, simultaneous wheel slipping on the front and rear axles, and frequent alternating slipping of the wheels on the front and rear axles;
[0075] The target required torque calculation unit 130 is used to obtain the accelerator pedal depth and, in combination with the vehicle speed, obtain the vehicle target required torque;
[0076] The front and rear axle torque distribution unit 140 is used to distribute the target required torque of the whole vehicle to the front and rear axle torques according to the current slip state of the vehicle, so as to improve the passability of the whole vehicle.
[0077] The front and rear axle torque distribution unit 140 includes:
[0078] The first torque distribution module 1401 is used for distributing the target torque of the whole vehicle to the front and rear axle torques according to a first distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slip state of the vehicle is that at least one wheel of the front axle slips and no wheel of the rear axle slips, if it is determined that the target torque required by the whole vehicle is greater than a first preset torque threshold value; or
[0079] If it is determined that the vehicle target demand torque is less than or equal to the first preset torque threshold value, the vehicle target demand torque is first distributed to the rear axle torque according to the preset first upper limit value, and then the remaining torque is distributed to the front axle torque.
[0080] The front and rear axle torque distribution unit 140 further includes:
[0081] The second torque distribution module 1402 is used for distributing the target torque of the whole vehicle to the front and rear axle torques according to a second distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slip state of the vehicle is that at least one wheel of the rear axle slips and no wheel of the front axle slips, if it is determined that the target torque required by the whole vehicle is greater than a second preset torque threshold value; or
[0082] If it is determined that the vehicle target demand torque is less than or equal to the second preset torque threshold value, the vehicle target demand torque is first distributed to the front axle torque according to the preset second upper limit value, and then the remaining torque is distributed to the rear axle torque.
[0083] The front and rear axle torque distribution unit 140 further includes:
[0084] A third torque distribution module 1403 is used for distributing the target torque of the vehicle to the front and rear axles according to a third distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slip state of the vehicle is that the wheels of the front and rear axles slip at the same time, if it is determined that the target torque required by the whole vehicle is greater than the third preset torque threshold value; or
[0085] If it is determined that the vehicle target demand torque is less than or equal to the third preset torque threshold value, the vehicle target demand torque is distributed to the front and rear axle torques according to a fourth distribution ratio pre-formed between the front axle torque and the rear axle torque.
[0086] The front and rear axle torque distribution unit 140 further includes:
[0087] The fourth torque distribution module 1404 is used for distributing the target torque of the whole vehicle to the front and rear axle torques according to a fifth distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slipping state of the vehicle is that the front and rear axle wheels slip frequently and alternately, if it is determined that the target torque required for the whole vehicle is greater than a fourth preset torque threshold value; or
[0088] If it is determined that the vehicle target demand torque is less than or equal to the fourth preset torque threshold value, the vehicle target demand torque is distributed to the front and rear axle torques according to a sixth distribution ratio pre-formed between the front axle torque and the rear axle torque.
[0089] Implementing the embodiments of the present invention has the following beneficial effects:
[0090] 1. The present invention realizes automatic identification of the current slipping state of the vehicle for correction of the required torque of the whole vehicle, avoiding the problem that the driver chooses whether to turn on the passability improvement function according to his own cognition, greatly improving the applicability of the function, so that the front and rear axle torques can be redistributed by technical means instead of the driver's precise control, so as to achieve the purpose of making the vehicle easily get out of trouble;
[0091] 2. The present invention can correct the torque redistribution under small torque demand, and will avoid the direct loss of the driving torque reduction of the axle where the slipping wheel is located by the vehicle stability control system ESP as much as possible, without obvious influence on the steering performance and driving comfort of the vehicle;
[0092] 3. The present invention can achieve vehicle escape based on a small throttle, which reduces the driver's operating requirements and has strong adaptability;
[0093] 4. The present invention does not require any additional hardware, and will not increase the cost of the vehicle or the design complexity of the transmission system.
[0094] It is worth noting that in the above system embodiment, the various system units included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of the various functional units are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.
[0095] A person skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, disk, CD-ROM, etc.
[0096] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.
Claims
1. A control method for improving vehicle trafficability, characterized in that: Used on a vehicle with a split-axle dual-motor four-wheel drive system, the method comprises the following steps: Get the vehicle speed and four wheel speeds; If the vehicle speed is greater than or equal to the preset vehicle speed threshold value, the current slip state of the vehicle is determined according to the wheel speeds of the four wheels; wherein the current slip state of the vehicle is one of at least one wheel slipping on the front axle and no wheel slipping on the rear axle, at least one wheel slipping on the rear axle and no wheel slipping on the front axle, wheel slipping on both the front and rear axles, and frequent alternating slipping of the wheels on the front and rear axles; Obtaining the accelerator pedal depth and combining it with the vehicle speed to obtain the vehicle target required torque; According to the current slip state of the vehicle, the target required torque of the whole vehicle is distributed to the front and rear axle torques to improve the passability of the whole vehicle; The step of distributing the target required torque of the vehicle to the front and rear axle torques according to the current slip state of the vehicle to improve the passability of the vehicle specifically includes: When the current slip state of the vehicle is that at least one wheel on the front axle slips and no wheel on the rear axle slips, if it is determined that the target required torque of the whole vehicle is greater than a first preset torque threshold value, the target required torque of the whole vehicle is distributed to the front and rear axle torques according to a first distribution ratio pre-formed between the front axle torque and the rear axle torque; If it is determined that the vehicle target demand torque is less than or equal to the first preset torque threshold value, the vehicle target demand torque is first distributed to the rear axle torque according to the preset first upper limit value, and then the remaining torque is distributed to the front axle torque.
2. The control method for improving vehicle trafficability according to claim 1, characterized in that: The step of distributing the target required torque of the vehicle to the front and rear axle torques according to the current slip state of the vehicle to improve the passability of the vehicle further specifically includes: When the current slip state of the vehicle is that at least one wheel of the rear axle slips but no wheel of the front axle slips, if it is determined that the target required torque of the whole vehicle is greater than a second preset torque threshold value, the target required torque of the whole vehicle is distributed to the front and rear axle torques according to a second distribution ratio pre-formed between the front axle torque and the rear axle torque; If it is determined that the vehicle target demand torque is less than or equal to the second preset torque threshold value, the vehicle target demand torque is first distributed to the front axle torque according to the preset second upper limit value, and then the remaining torque is distributed to the rear axle torque.
3. The control method for improving vehicle trafficability according to claim 1, characterized in that: The step of distributing the target required torque of the vehicle to the front and rear axle torques according to the current slip state of the vehicle to improve the passability of the vehicle further includes: When the current slip state of the vehicle is that wheels on both the front and rear axles slip at the same time, if it is determined that the target required torque of the entire vehicle is greater than a third preset torque threshold value, the target required torque of the entire vehicle is distributed to the front and rear axles according to a third distribution ratio pre-formed between the front axle torque and the rear axle torque; If it is determined that the vehicle target demand torque is less than or equal to the third preset torque threshold value, the vehicle target demand torque is distributed to the front and rear axle torques according to a fourth distribution ratio pre-formed between the front axle torque and the rear axle torque.
4. The control method for improving vehicle trafficability as claimed in claim 1, characterized in that: The step of distributing the target required torque of the vehicle to the front and rear axle torques according to the current slip state of the vehicle to improve the passability of the vehicle further includes: When the current slipping state of the vehicle is that the front and rear axle wheels slip frequently and alternately, if it is determined that the whole vehicle target demand torque is greater than a fourth preset torque threshold value, the whole vehicle target demand torque is distributed to the front and rear axle torques according to a fifth distribution ratio pre-formed between the front axle torque and the rear axle torque; If it is determined that the vehicle target demand torque is less than or equal to the fourth preset torque threshold value, the vehicle target demand torque is distributed to the front and rear axle torques according to a sixth distribution ratio pre-formed between the front axle torque and the rear axle torque.
5. A control system for improving vehicle trafficability, characterized in that: Used in vehicles with split-axle dual-motor four-wheel drive systems, it includes a vehicle speed and wheel speed acquisition unit, a slip state determination unit, a target demand torque calculation unit, and a front and rear axle torque distribution unit; wherein, The vehicle speed and wheel speed acquisition unit is used to acquire the vehicle speed and the wheel speeds of the four wheels; The slip state determination unit is used to determine the current slip state of the vehicle according to the wheel speeds of the four wheels if the vehicle speed is greater than or equal to a preset vehicle speed threshold value; wherein the current slip state of the vehicle is one of at least one wheel slipping on the front axle and no wheel slipping on the rear axle, at least one wheel slipping on the rear axle and no wheel slipping on the front axle, simultaneous wheel slipping on the front and rear axles, and frequent alternating slipping of the wheels on the front and rear axles; The target required torque calculation unit is used to obtain the accelerator pedal depth and, in combination with the vehicle speed, obtain the vehicle's entire vehicle target required torque; The front and rear axle torque distribution unit is used to distribute the target required torque of the whole vehicle to the front and rear axle torques according to the current slip state of the vehicle, so as to improve the passability of the whole vehicle; The front and rear axle torque distribution unit comprises: The first torque distribution module is used to distribute the front and rear axle torques according to a first distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slip state of the vehicle is that at least one wheel on the front axle slips but no wheel on the rear axle slips. If it is determined that the target demand torque of the whole vehicle is greater than a first preset torque threshold value, the target demand torque of the whole vehicle is distributed to the front and rear axle torques according to a first distribution ratio pre-formed between the front axle torque and the rear axle torque; if it is determined that the target demand torque of the whole vehicle is less than or equal to the first preset torque threshold value, the target demand torque of the whole vehicle is first distributed to the rear axle torque according to a preset first upper limit value, and then the remaining torque is distributed to the front axle torque.
6. The control system for improving vehicle trafficability as claimed in claim 5, characterized in that: The front and rear axle torque distribution unit further includes: The second torque distribution module is used to distribute the front and rear axle torques according to a second distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slip state of the vehicle is that at least one wheel on the rear axle slips but no wheel on the front axle slips. If it is determined that the target demand torque of the whole vehicle is greater than a second preset torque threshold value, the target demand torque of the whole vehicle is distributed to the front and rear axle torques according to a second distribution ratio pre-formed between the front axle torque and the rear axle torque; if it is determined that the target demand torque of the whole vehicle is less than or equal to the second preset torque threshold value, the target demand torque of the whole vehicle is first distributed to the front axle torque according to a preset second upper limit value, and then the remaining torque is distributed to the rear axle torque.
7. The control system for improving vehicle trafficability as claimed in claim 5, characterized in that: The front and rear axle torque distribution unit further includes: The third torque distribution module is used for distributing the target torque of the whole vehicle to the front and rear axles according to a third distribution ratio pre-formed between the front axle torque and the rear axle torque when the current slip state of the vehicle is that the wheels on the front and rear axles slip at the same time. If it is determined that the target torque required by the whole vehicle is greater than a third preset torque threshold value, the target torque required by the whole vehicle is distributed to the front and rear axles according to a third distribution ratio pre-formed between the front axle torque and the rear axle torque; if it is determined that the target torque required by the whole vehicle is less than or equal to the third preset torque threshold value, the target torque required by the whole vehicle is distributed to the front and rear axles according to a fourth distribution ratio pre-formed between the front axle torque and the rear axle torque.
8. The control system for improving vehicle trafficability as claimed in claim 5, characterized in that: The front and rear axle torque distribution unit further includes: The fourth torque distribution module is used to distribute the front and rear axle torques according to a fifth distribution ratio pre-formed by the front axle torque and the rear axle torque when the current slip state of the vehicle is that the front and rear axle wheels slip frequently and alternately. If it is determined that the target demand torque of the whole vehicle is greater than the fourth preset torque threshold value, the target demand torque of the whole vehicle is distributed to the front and rear axle torques according to a fifth distribution ratio pre-formed by the front axle torque and the rear axle torque; if it is determined that the target demand torque of the whole vehicle is less than or equal to the fourth preset torque threshold value, the target demand torque of the whole vehicle is distributed to the front and rear axle torques according to a sixth distribution ratio pre-formed by the front axle torque and the rear axle torque.