Motor torque limiting method, device, vehicle controller and vehicle

Abstract

The present application relates to the field of new energy vehicle technology, and in particular to a motor torque limiting method, device, vehicle controller and vehicle. The method comprises: obtaining tire status information and motor status information, wherein the tire status information indicates whether the tire is slipping, and the motor status information indicates whether the motor speed has failed; based on the tire status information and the motor status information, calculating the corresponding motor correction speed, and updating the collected motor current speed according to the motor correction speed; determining the power distribution ratio according to the motor current speed; calculating the motor torque limit value according to the power distribution ratio, and limiting the obtained motor original output torque according to the motor torque limit value. The use of this method can improve the problems of difficult power estimation and unreasonable power distribution in scenarios such as tire slippage and motor speed failure.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicle technology, and in particular to a motor torque limiting method, device, vehicle controller, and vehicle. Background Art

[0002] In recent years, motor torque limitation methods for new energy vehicles have been widely studied and applied. The main purpose is to ensure the safety of power batteries and extend their service life, thereby ensuring the vehicle's power performance and driving stability.

[0003] At present, common motor torque limitation methods mainly include speed-based motor torque limitation methods, which monitor the motor speed in real time. When the speed exceeds a preset limit, the motor torque output is controlled to limit the speed.

[0004] However, this method is difficult to apply to scenarios such as tire slippage and motor speed failure, and cannot cope with problems such as difficulty in power estimation and unreasonable power distribution, which in turn leads to insufficient vehicle power or excessive power. Summary of the Invention

[0005] Based on this, a motor torque limiting method, device, vehicle controller and vehicle are provided to improve problems such as difficult power estimation and unreasonable power distribution in scenarios such as tire slippage and motor speed failure.

[0006] In a first aspect, a method for limiting motor torque is provided, the method comprising:

[0007] Acquiring tire status information and motor status information, wherein the tire status information indicates whether the tire is slipping, and the motor status information indicates whether the motor speed is failing;

[0008] Calculating a corresponding motor correction speed based on the tire state information and the motor state information, and updating the collected motor current speed according to the motor correction speed;

[0009] determining a power distribution ratio according to the current speed of the motor;

[0010] A motor torque limit value is calculated according to the power distribution ratio, and the acquired original output torque of the motor is limited according to the motor torque limit value.

[0011] In conjunction with the first aspect, in a first possible implementation manner of the first aspect, the steps of calculating a corresponding corrected motor speed based on the tire state information and the motor state information, and updating the collected current motor speed according to the corrected motor speed include:

[0012] When the tire status information indicates that the tire is not slipping and the motor status information indicates that only the front motor speed has failed, calculating a corrected front motor speed using the collected current rear motor speed, and updating the collected current front motor speed based on the corrected front motor speed;

[0013] When the tire status information indicates that the tire is not slipping and the motor status information indicates that only the rear motor speed has failed, calculating a corrected rear motor speed based on the collected current front motor speed, and updating the collected current rear motor speed based on the corrected rear motor speed;

[0014] When the tire status information indicates that the tire is not slipping and the motor status information indicates that the front and rear motor speeds are both invalid, a front motor correction speed is calculated based on the collected wheel speed corresponding to the front axle and a preset front motor speed ratio, and the collected current front motor speed is updated based on the front motor correction speed; a rear motor correction speed is calculated based on the collected wheel speed corresponding to the rear axle and a preset rear motor speed ratio, and the collected current rear motor speed is updated based on the rear motor correction speed;

[0015] The motor correction speed includes at least one of the front motor correction speed and the rear motor correction speed.

[0016] In combination with the first possible implementation of the first aspect, in a second possible implementation of the first aspect, the step of calculating the corresponding motor correction speed based on the tire state information and the motor state information, and updating the collected current motor speed according to the motor correction speed further includes:

[0017] When the tire state information indicates tire slip and the motor state information indicates that both front and rear motor speeds have failed, obtaining a current adhesion coefficient, a current tire slip state, and a wheel speed of the slipping wheel, wherein the current tire slip state indicates one of unilateral slip and bilateral slip;

[0018] Obtaining a corresponding current speed correction coefficient according to the current adhesion coefficient, the current tire slip state, and a preset mapping relationship, wherein the mapping relationship records the relationship between different tire slip states, adhesion coefficients, and speed correction coefficients;

[0019] The motor correction speed is obtained according to the product of the slipping wheel speed and the current speed correction coefficient, and the collected current speeds of the front motor and the rear motor are updated according to the motor correction speed.

[0020] In combination with the second possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, the step of calculating the corresponding motor correction speed based on the tire state information and the motor state information, and updating the collected current motor speed according to the motor correction speed further includes:

[0021] When the tire status information indicates tire slippage and the motor status information indicates that only the front motor speed has failed, a first front motor estimated speed is calculated using the collected current speed of the rear motor and a second front motor estimated speed is calculated using the collected current wheel speed of the front motor; the first front motor estimated speed and the second front motor estimated speed are fused and calculated to obtain a corrected front motor speed, and the collected current front motor speed is updated based on the corrected front motor speed;

[0022] When the tire status information indicates that the tire is slipping and the motor status information indicates that only the rear motor speed has failed, the first rear motor estimated speed is calculated using the collected current speed of the front motor and the second rear motor estimated speed is calculated using the collected current wheel speed of the rear motor; the first rear motor estimated speed and the second rear motor estimated speed are fused and calculated to obtain a corrected rear motor speed, and the collected current rear motor speed is updated based on the corrected rear motor speed.

[0023] In combination with the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the step of calculating the estimated speed of the second front motor based on the collected current wheel speed of the front motor includes: calculating a front motor conversion speed based on the current wheel speed of the front motor and a preset front motor speed ratio; and obtaining the second front motor estimated speed based on the product of the front motor conversion speed and the current speed correction coefficient;

[0024] The step of calculating the estimated speed of the second rear motor by collecting the current wheel speed of the rear motor includes: calculating the conversion speed of the rear motor according to the current wheel speed of the rear motor and the preset rear motor speed ratio; and obtaining the estimated speed of the second rear motor according to the product of the conversion speed of the rear motor and the current speed correction coefficient.

[0025] In combination with the first aspect, in a fifth possible implementation manner of the first aspect, the step of determining the power distribution ratio according to the current speed of the motor includes:

[0026] Obtain the front motor torque and the rear motor torque;

[0027] When the current speed of the motor is greater than or equal to a preset threshold, calculating the power distribution ratio according to the front motor torque, the rear motor torque and the current speed of the motor;

[0028] When the current speed of the motor is less than the preset threshold, calculating the power distribution ratio according to the front motor torque and the rear motor torque;

[0029] The current motor speed includes the current front motor speed and the current rear motor speed, and the power distribution ratio includes the front motor power distribution ratio and the rear motor power distribution ratio.

[0030] In combination with the first aspect, in a sixth possible implementation manner of the first aspect, the step of calculating the motor torque limit value according to the power distribution ratio, and limiting the obtained original output torque of the motor according to the motor torque limit value includes:

[0031] Calculating a motor torque limit value according to the power distribution ratio, the current motor speed, and a preset motor allowable power, wherein the motor torque limit value includes a front motor torque limit value and a rear motor torque limit value;

[0032] When the motor torque limit value is a positive value, the minimum value between the motor torque limit value and the original output torque of the motor is used as the final output torque of the motor;

[0033] When the motor torque limit value is a negative value, the maximum value between the motor torque limit value and the original output torque of the motor is used as the final output torque of the motor.

[0034] In a second aspect, a motor torque limiting device is provided, the device comprising:

[0035] a state acquisition unit, configured to acquire tire state information and motor state information, wherein the tire state information indicates whether the tire is slipping, and the motor state information indicates whether the motor speed is ineffective;

[0036] a motor speed correction unit, configured to calculate a corresponding motor speed correction based on the tire state information and the motor state information, and update the collected current motor speed according to the motor speed correction;

[0037] A power distribution ratio determination unit is used to determine the power distribution ratio according to the current speed of the motor; a torque limitation unit is used to calculate the motor torque limit value according to the power distribution ratio and limit the obtained motor original output torque according to the motor torque limit value.

[0038] In a third aspect, a vehicle controller is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the motor torque limiting method as described in any one of the first to sixth possible implementations of the first aspect or in combination with the first aspect are implemented.

[0039] In a fourth aspect, a vehicle is provided, comprising the vehicle controller as described in the third aspect.

[0040] The motor torque limiting method, device, vehicle controller, and vehicle described above obtain tire status information and motor status information, wherein the tire status information indicates whether the tire is slipping and the motor status information indicates whether the motor speed has failed; calculate the corresponding motor correction speed based on the tire status information and the motor status information, and update the acquired motor current speed according to the motor correction speed; redetermine the power distribution ratio according to the updated motor current speed; calculate the motor torque limit value according to the power distribution ratio, and limit the acquired motor original output torque according to the motor torque limit value. It can be seen that compared with the prior art, the motor torque limiting method of the present application has the beneficial effect of realizing redundant calculation of the motor speed in scenarios such as tire slipping and motor speed failure, improving the accuracy of the motor speed, thereby avoiding the problem of difficulty in estimating the power after the motor speed fails; and redetermining the power distribution ratio based on the motor speed obtained by the redundant calculation can avoid the problem of unreasonable power distribution to a certain extent, thereby improving the problems of insufficient vehicle power or excessive power, and improving the vehicle's power performance and driving stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 1 is a flow chart of a method for limiting motor torque in one embodiment;

[0042] Figure 2 FIG. 4 is a structural block diagram of a motor torque limiting device in one embodiment. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0044] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present application in a schematic manner. Therefore, the illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0045] The structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not intended to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modifications, changes in proportional relationships, or adjustments in size, without affecting the efficacy and objectives that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0046] The directions or positional relationships indicated in this specification, such as "upper," "lower," "left," "right," "center," "longitudinal," "transverse," "horizontal," "inner," "outer," "radial," and "circumferential," are based on the directions or positional relationships shown in the accompanying drawings and are intended solely for the purpose of simplifying the description. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In one embodiment, Figure 1 As shown, a motor torque limiting method is provided, which is described by taking the application of the method to a vehicle controller as an example, and includes the following steps:

[0048] Step 202: Obtain tire status information and motor status information.

[0049] Among them, the tire status information indicates whether the tire is slipping, and tire slipping includes unilateral slipping and bilateral slipping; the motor status information indicates whether the motor speed has failed, and motor speed failure includes only the front motor speed failure, only the rear motor speed failure, and both the front and rear motor speeds fail.

[0050] As a specific implementation, whether the tire is slipping can be determined based on the wheel speed and vehicle speed, specifically including: taking the first-order derivative of the wheel speed to calculate the corresponding wheel acceleration; calculating the slip rate based on the wheel speed and vehicle speed; and determining that the tire is slipping when the wheel acceleration is greater than a preset acceleration threshold and the slip rate is also greater than a preset slip rate threshold.

[0051] Among them, the steps of calculating the slip rate based on the wheel speed and vehicle speed include: when the wheel speed is greater than the vehicle speed, the slip rate = (wheel speed - vehicle speed) / wheel speed × 100%; when the vehicle speed is greater than the wheel speed, the slip rate = (vehicle speed - wheel speed) / vehicle speed × 100%; the tire slip flag can also be set in advance. When it is determined that the tire is slipping, the tire slip flag is set, otherwise the tire slip flag is reset.

[0052] Motor speed failure means that the current motor speed cannot correctly represent the actual motor speed due to factors such as sensor failure. When motor speed failure occurs, the motor controller will send a motor speed invalid command.

[0053] Step 204 : Calculate the corresponding motor correction speed based on the tire state information and the motor state information, and update the collected motor current speed according to the motor correction speed.

[0054] As a specific implementation, step 204 may specifically include: when the tire status information indicates that the tire is not slipping and the motor status information indicates that only the front motor speed has failed, calculating the front motor corrected speed by using the collected current speed of the rear motor, and updating the collected current speed of the front motor according to the front motor corrected speed; when the tire status information indicates that the tire is not slipping and the motor status information indicates that only the rear motor speed has failed, calculating the rear motor corrected speed by using the collected current speed of the front motor, and updating the collected current speed of the rear motor according to the rear motor corrected speed; when the tire status information indicates that the tire is not slipping and the motor status information indicates that both the front and rear motor speeds have failed, calculating the front motor corrected speed by using the collected wheel speed corresponding to the front axle and a preset front motor speed ratio, and updating the collected current speed of the front motor according to the front motor corrected speed; calculating the rear motor corrected speed by using the collected wheel speed corresponding to the rear axle and a preset rear motor speed ratio, and updating the collected current speed of the rear motor according to the rear motor corrected speed; wherein the motor corrected speed includes at least one of the front motor corrected speed and the rear motor corrected speed.

[0055] In the above steps, the mathematical expressions used to calculate the front motor correction speed by collecting the current speed of the rear motor include: f_x =n r ×(i f / i r ), where n f_x Indicates the corrected speed of the front motor, n r Indicates the current speed of the rear motor, i f Indicates the front motor speed ratio, i r Indicates the rear motor speed ratio; the mathematical expressions used to calculate the rear motor correction speed by collecting the current speed of the front motor include: n r_x =n f ×(i r / i f ), where n r_x Indicates the corrected speed of the rear motor, n f Indicates the current speed of the front motor; the mathematical expressions used to calculate the front motor correction speed by collecting the wheel speed corresponding to the front axle and the preset front motor speed ratio include: n f_x =(V f_wheel ×60×i f ) / (2πr×3.6), where V f_wheel Indicates the wheel speed corresponding to the front axle. Since the wheel speeds of the left and right wheels connected to the front axle are not much different when the tires are not slipping, V f_wheel Either the left front wheel speed or the right front wheel speed can be used, and r represents the tire rolling radius. Similarly, the mathematical expressions used to calculate the rear motor correction speed by collecting the wheel speed corresponding to the rear axle and the preset rear motor speed ratio include: nr_x =(V r_wheel ×60×i r ) / (2πr×3.6), where V r_wheel Indicates the wheel speed corresponding to the rear axle. Since the wheel speeds of the left and right wheels connected to the rear axle are not much different when the tires are not slipping, V r_wheel Either the left rear wheel speed or the right rear wheel speed can be used.

[0056] Furthermore, step 204 may also include: when the tire status information indicates tire slip and the motor status information indicates that the front and rear motor speeds are both failed, obtaining the current adhesion coefficient, the current tire slip status and the slipping wheel speed, wherein the current tire slip status indicates one of unilateral slip and bilateral slip; obtaining the corresponding current speed correction coefficient according to the current adhesion coefficient, the current tire slip status and a preset mapping relationship, wherein the mapping relationship records the relationship between different tire slip states, adhesion coefficients and speed correction coefficients; obtaining the motor correction speed according to the product of the slipping wheel speed and the current speed correction coefficient, and updating the collected front motor current speed and rear motor current speed according to the motor correction speed.

[0057] It should be noted that, since the degree of slippage of each tire on a uniform road surface is not much different, the wheel speed of the slipping wheel can be taken as the wheel speed of any slipping tire; and regardless of whether it is unilateral slippage or bilateral slippage, since the front and rear motor speeds are both invalid, after calculating the motor correction speed, the current speed values ​​of the front and rear motors are replaced by the motor correction speed values ​​to achieve the update of the current speeds of the front and rear motors.

[0058] In the mapping relationship, under the same adhesion coefficient, the speed correction coefficients corresponding to unilateral slip and bilateral slip are different, with the speed correction coefficient corresponding to unilateral slip being smaller than that corresponding to bilateral slip. This mapping relationship can be determined through actual vehicle testing. For example, compared to ordinary roads, vehicles are more likely to experience tire slip when driving on snow and ice. Through actual vehicle testing, the mapping relationship shown in Table 1 can be obtained:

[0059] Table 1 Mapping relationship

[0060]

[0061] Furthermore, step 204 may also include: when the tire status information indicates that the tire is slipping and the motor status information indicates that only the front motor speed is invalid, calculating the first front motor estimated speed by using the collected current speed of the rear motor and calculating the second front motor estimated speed by using the collected current wheel speed of the front motor; fusing the first front motor estimated speed and the second front motor estimated speed to obtain the front motor corrected speed, and updating the collected current speed of the front motor according to the front motor corrected speed; when the tire status information indicates that the tire is slipping and the motor status information indicates that only the rear motor speed is invalid, calculating the first rear motor estimated speed by using the collected current speed of the front motor and calculating the second rear motor estimated speed by using the collected current wheel speed of the rear motor; fusing the first rear motor estimated speed and the second rear motor estimated speed to obtain the rear motor corrected speed, and updating the collected current speed of the rear motor according to the rear motor corrected speed; wherein, the motor corrected speed includes at least one of the front motor corrected speed and the rear motor corrected speed.

[0062] In the above steps, the mathematical expression used to calculate the estimated speed of the first front motor is the same as the mathematical expression used to calculate the corrected speed of the front motor through the current speed of the rear motor in the above steps. The mathematical expression used to calculate the estimated speed of the first rear motor is the same as the mathematical expression used to calculate the corrected speed of the rear motor through the current speed of the front motor in the above steps. The relevant content can be found in the specific limitations above and will not be repeated here.

[0063] It should be noted that when the current motor speed fails but the rear motor speed does not fail, the actual current speed of the front motor can be roughly equal to the approximate value obtained by reversely calculating the current speed of the rear motor through the front and rear motor speed ratio conversion (that is, the above-mentioned first front motor estimated speed); but this approximate value is difficult to represent the actual current speed of the front motor, so the approximate value is corrected by reversely calculating the current speed of the front motor to the corresponding speed (that is, the above-mentioned second front motor estimated speed) to obtain the final current speed of the front motor (that is, the corrected front motor speed) to improve the accuracy of the current speed of the front motor.

[0064] Similarly, when the rear motor speed fails but the front motor speed does not fail, the actual current speed of the rear motor can be roughly equal to the approximate value obtained by reversely calculating the current speed of the front motor through the front and rear motor speed ratio conversion (i.e., the above-mentioned first rear motor estimated speed); but this approximate value is difficult to represent the actual current speed of the rear motor, so the approximate value is corrected by reversely calculating the current speed of the rear motor into the corresponding speed (i.e., the above-mentioned second rear motor estimated speed) to obtain the final current speed of the rear motor (i.e., the rear motor corrected speed) to improve the accuracy of the current speed of the rear motor.

[0065] In the above steps, the step of fusing the estimated speed of the first front motor and the estimated speed of the second front motor to obtain the corrected speed of the front motor specifically includes: looking up a table based on the current adhesion coefficient to obtain a current fusion coefficient, wherein the table records the relationship between different adhesion coefficients and fusion coefficients determined through actual vehicle testing and calibration, and the fusion coefficient is used to fuse the estimated speed of the first front motor and the estimated speed of the second front motor, and the lower the adhesion coefficient, the higher the proportion of the estimated speed of the first front motor in the fusion calculation process; fusing the estimated speed of the first front motor and the estimated speed of the second front motor by the current fusion coefficient to obtain the corrected speed of the front motor, wherein the mathematical expressions used include: n f_x =μ×n f_Wheel +(1-μ)×n f_Motor , n f_x Indicates the corrected speed of the front motor, μ indicates the current fusion coefficient, n f_Wheel Indicates the estimated speed of the second front motor, n f_Motor Indicates the estimated speed of the first front motor.

[0066] Similarly, the step of fusing the estimated speed of the first rear motor and the estimated speed of the second rear motor to obtain the corrected speed of the rear motor specifically includes: looking up a table based on the current adhesion coefficient to obtain a current fusion coefficient, wherein the table records the relationship between different adhesion coefficients and fusion coefficients determined through actual vehicle testing and calibration, and the fusion coefficient is used to fuse the estimated speed of the first rear motor and the estimated speed of the second rear motor, and the lower the adhesion coefficient, the higher the proportion of the estimated speed of the first rear motor in the fusion calculation process; fusing the estimated speed of the first rear motor and the estimated speed of the second rear motor through the current fusion coefficient to obtain the corrected speed of the rear motor, wherein the mathematical expressions used include: n r_x =μ×n r_Wheel +(1-μ)×n r_Motor , n r_x Indicates the corrected speed of the rear motor, μ indicates the fusion coefficient, n r_Wheel Indicates the estimated speed of the second rear motor, n r_Motor Indicates the estimated speed of the first rear motor.

[0067] In the above steps, the step of calculating the estimated speed of the second front motor by collecting the current wheel speed of the front motor includes: calculating the front motor conversion speed according to the current wheel speed of the front motor and the preset front motor speed ratio; obtaining the second front motor estimated speed according to the product of the front motor conversion speed and the current speed correction coefficient; the step of calculating the estimated speed of the second rear motor by collecting the current wheel speed of the rear motor includes: calculating the rear motor conversion speed according to the current wheel speed of the rear motor and the preset rear motor speed ratio; obtaining the second rear motor estimated speed according to the product of the rear motor conversion speed and the current speed correction coefficient.

[0068] Among them, the calculation of the front motor conversion speed is the same as the mathematical expression used in the aforementioned step to calculate the front motor correction speed through the wheel speed corresponding to the front axle and the preset front motor speed ratio. The calculation of the rear motor conversion speed is the same as the mathematical expression used in the aforementioned step to calculate the rear motor correction speed through the wheel speed corresponding to the rear axle and the preset rear motor speed ratio. Relevant content can be found in the specific limitations above, and the specific limitations of the above-mentioned current speed correction coefficient can also be found in the specific limitations above, which will not be repeated here.

[0069] It should also be noted that in the step of updating the collected current motor speed according to the corrected motor speed, it is sufficient to update the current speed of the motor whose speed has failed. The current speed of the motor whose speed has not failed does not need to be updated, and the current speed collected by the sensor can be directly used.

[0070] Step 206: Determine the power distribution ratio according to the current speed of the motor.

[0071] As a specific implementation, step 206 may specifically include: obtaining the front motor torque and the rear motor torque; when the current speed of the motor is greater than or equal to a preset threshold, calculating the power distribution ratio based on the front motor torque, the rear motor torque and the current speed of the motor; when the current speed of the motor is less than the preset threshold, calculating the power distribution ratio based on the front motor torque and the rear motor torque; wherein, the current speed of the motor includes the current speed of the front motor and the current speed of the rear motor, and the power distribution ratio includes the front motor power distribution ratio and the rear motor power distribution ratio.

[0072] For example, the power distribution ratio is calculated differently based on different vehicle models and different application scenarios. Specifically, when the vehicle is configured with two-wheel drive, the power distribution ratio is equal to 1. When the vehicle is configured with four-wheel drive, the following situations may occur:

[0073] The first method is to obtain the front motor power according to the product of the front motor torque and the current speed of the front motor, obtain the rear motor power according to the product of the rear motor torque and the current speed of the rear motor, obtain the total power according to the sum of the front motor power and the rear motor power, obtain the front motor power distribution ratio according to the quotient of the front motor power and the total power, and obtain the rear motor power distribution ratio according to the quotient of the rear motor power and the total power;

[0074] The second type is that when the current speed of the motor is less than a preset threshold, for example, when the current speed of the motor fluctuates around zero, in order to avoid fluctuations in the power distribution ratio, the total torque is obtained according to the sum of the front motor torque and the rear motor torque, the front motor power distribution ratio is obtained according to the quotient of the front motor torque and the total torque, and the rear motor power distribution ratio is obtained according to the quotient of the rear motor torque and the total torque.

[0075] The third type is when the motor sensor is abnormal and cannot indicate the front and rear motor speeds and wheel speeds, and there is no available information to calculate the true motor speed, the front motor power distribution ratio and the rear motor power distribution ratio are evenly divided.

[0076] Step 208 : Calculate the motor torque limit value according to the power distribution ratio, and limit the acquired original output torque of the motor according to the motor torque limit value.

[0077] Among them, the step of calculating the motor torque limit value according to the power distribution ratio specifically includes: calculating the motor torque limit value according to the power distribution ratio, the current speed of the motor and the preset motor allowable power, wherein the motor torque limit value includes the front motor torque limit value and the rear motor torque limit value.

[0078] Specifically, the front motor torque limit value is calculated based on the front motor power distribution ratio, the current front motor speed, and the preset front motor allowable power; the rear motor torque limit value is calculated based on the rear motor power distribution ratio, the current rear motor speed, and the preset rear motor allowable power; wherein, the mathematical expressions used to calculate the front and rear motor torque limit values ​​include: T x =i x ×(9550×P x_allow / n x ), T x Indicates the front motor torque limit value or the rear motor torque limit value, i x Indicates the front motor power distribution ratio or the rear motor power distribution ratio, P x_allow Indicates the front motor allowed power or the rear motor allowed power, n x Indicates the current speed of the front motor or the current speed of the rear motor.

[0079] After the motor torque limit value is calculated, when the motor torque limit value is a positive value, the minimum value between the motor torque limit value and the original output torque of the motor is used as the final output torque of the motor; when the motor torque limit value is a negative value, the maximum value between the motor torque limit value and the original output torque of the motor is used as the final output torque of the motor.

[0080] In summary, the above-mentioned motor torque limiting method obtains tire status information and motor status information, and calculates the corresponding motor correction speed based on the tire status information and the motor status information, and updates the acquired motor current speed according to the motor correction speed; redetermines the power distribution ratio according to the updated motor current speed; and then calculates the motor torque limit value according to the power distribution ratio to limit the original output torque of the motor according to the motor torque limit value. It can be seen that the motor torque limiting method of the present application improves the accuracy of the motor speed by redundantly calculating the motor speed in scenarios such as tire slippage and motor speed failure, thereby avoiding the problem of difficulty in estimating the power after the motor speed fails; and redetermines the power distribution ratio based on the motor speed obtained by the redundant calculation, which can avoid the problem of unreasonable power distribution to a certain extent, thereby improving problems such as insufficient vehicle power or excessive power, and improving the vehicle's power performance and driving stability.

[0081] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0082] In one embodiment, Figure 2 As shown, a motor torque limiting device is provided, comprising: a state acquisition unit, a motor speed correction unit, a power distribution ratio determination unit and a torque limiting unit, wherein:

[0083] a state acquisition unit, configured to acquire tire state information and motor state information, wherein the tire state information indicates whether the tire is slipping, and the motor state information indicates whether the motor speed is ineffective;

[0084] a motor speed correction unit, configured to calculate a corresponding motor speed correction based on the tire state information and the motor state information, and update the collected current motor speed according to the motor speed correction;

[0085] a power distribution ratio determining unit, configured to determine the power distribution ratio according to the current speed of the motor;

[0086] The torque limiting unit is configured to calculate a motor torque limit value according to the power distribution ratio, and to limit the acquired original output torque of the motor according to the motor torque limit value.

[0087] In a specific embodiment, the motor speed correction unit is used to calculate the corresponding motor correction speed based on the tire status information and the motor status information, and update the collected current motor speed according to the motor correction speed, specifically including: when the tire status information indicates that the tire is not slipping and the motor status information indicates that only the front motor speed is invalid, the front motor correction speed is calculated by using the collected current speed of the rear motor, and the collected current speed of the front motor is updated according to the front motor correction speed; when the tire status information indicates that the tire is not slipping and the motor status information indicates that only the rear motor speed is invalid, the rear motor correction speed is calculated by using the collected current speed of the front motor. The motor corrected speed is calculated based on the collected wheel speed corresponding to the front axle and the preset front motor speed ratio, and the collected current speed of the rear motor is updated according to the rear motor corrected speed; when the tire status information indicates that the tire is not slipping and the motor status information indicates that the front and rear motor speeds are both invalid, the front motor corrected speed is calculated based on the collected wheel speed corresponding to the front axle and the preset front motor speed ratio, and the collected current speed of the front motor is updated according to the front motor corrected speed; the rear motor corrected speed is calculated based on the collected wheel speed corresponding to the rear axle and the preset rear motor speed ratio, and the collected current speed of the rear motor is updated according to the rear motor corrected speed; wherein, the motor corrected speed includes at least one of the front motor corrected speed and the rear motor corrected speed.

[0088] In a specific embodiment, the motor speed correction unit is used to calculate the corresponding motor correction speed based on the tire status information and the motor status information, and update the collected current motor speed according to the motor correction speed, specifically including: when the tire status information indicates tire slip and the motor status information indicates that both the front and rear motor speeds are invalid, obtaining the current adhesion coefficient, the current tire slip state and the slipping wheel speed, wherein the current tire slip state represents one of unilateral slip and bilateral slip; obtaining the corresponding current speed correction coefficient according to the current adhesion coefficient, the current tire slip state and a preset mapping relationship, wherein the mapping relationship records the relationship between different tire slip states, adhesion coefficients and speed correction coefficients; obtaining the motor correction speed according to the product of the slipping wheel speed and the current speed correction coefficient, and updating the collected current speed of the front motor and the current speed of the rear motor according to the motor correction speed.

[0089] In a specific embodiment, the motor speed correction unit is used to calculate the corresponding motor correction speed based on the tire status information and the motor status information, and update the collected current motor speed according to the motor correction speed, specifically including: when the tire status information indicates tire slippage and the motor status information indicates that only the front motor speed is invalid, calculating a first front motor estimated speed by using the collected current speed of the rear motor and calculating a second front motor estimated speed by using the collected current wheel speed of the front motor; fusing the first front motor estimated speed and the second front motor estimated speed to obtain a front motor correction speed, and updating the collected current front motor speed according to the front motor correction speed; when the tire status information indicates tire slippage and the motor status information indicates that only the rear motor speed is invalid, calculating a first rear motor estimated speed by using the collected current speed of the front motor and calculating a second rear motor estimated speed by using the collected current wheel speed of the rear motor; fusing the first rear motor estimated speed and the second rear motor estimated speed to obtain a rear motor correction speed, and updating the collected current rear motor speed according to the rear motor correction speed; wherein the motor correction speed includes at least one of the front motor correction speed and the rear motor correction speed.

[0090] In a specific embodiment, the motor speed correction unit is used to calculate the second front motor estimated speed through the collected current wheel speed of the front motor, specifically including: calculating the front motor conversion speed based on the current wheel speed of the front motor and the preset front motor speed ratio; obtaining the second front motor estimated speed based on the product of the front motor conversion speed and the current speed correction coefficient; the motor speed correction unit is used to calculate the second rear motor estimated speed through the collected current wheel speed of the rear motor, specifically including: calculating the rear motor conversion speed based on the current wheel speed of the rear motor and the preset rear motor speed ratio; obtaining the second rear motor estimated speed based on the product of the rear motor conversion speed and the current speed correction coefficient.

[0091] The power distribution ratio determination unit is used to determine the power distribution ratio according to the current speed of the motor, specifically including: obtaining the front motor torque and the rear motor torque; when the current speed of the motor is greater than or equal to a preset threshold, calculating the power distribution ratio according to the front motor torque, the rear motor torque and the current speed of the motor; when the current speed of the motor is less than the preset threshold, calculating the power distribution ratio according to the front motor torque and the rear motor torque; wherein, the current speed of the motor includes the current speed of the front motor and the current speed of the rear motor, and the power distribution ratio includes the front motor power distribution ratio and the rear motor power distribution ratio.

[0092] The torque limiting unit is used to calculate the motor torque limit value according to the power distribution ratio, and limit the obtained motor original output torque according to the motor torque limit value, specifically including: calculating the motor torque limit value according to the power distribution ratio, the current motor speed and the preset motor allowable power, wherein the motor torque limit value includes the front motor torque limit value and the rear motor torque limit value; when the motor torque limit value is a positive value, the minimum value between the motor torque limit value and the motor original output torque is used as the motor final output torque; when the motor torque limit value is a negative value, the maximum value between the motor torque limit value and the motor original output torque is used as the motor final output torque.

[0093] The specific definition of the motor torque limiting device can be found in the definition of the motor torque limiting method above and will not be repeated here. Each module in the aforementioned motor torque limiting device can be implemented in whole or in part via software, hardware, or a combination thereof. Each of the aforementioned modules can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a computer device memory in software form, so that the processor can call and execute the corresponding operations of each module.

[0094] In one embodiment, a vehicle controller is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the motor torque limiting method described in the foregoing embodiment are implemented.

[0095] In one embodiment, a vehicle is provided, comprising the vehicle controller described in the above embodiment.

[0096] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0097] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A motor torque limiting method, characterized in that: include: Acquiring tire status information and motor status information, wherein the tire status information indicates whether the tire is slipping, and the motor status information indicates whether the motor speed is failing; Calculating a corresponding motor correction speed based on the tire state information and the motor state information, and updating the collected motor current speed according to the motor correction speed; determining a power distribution ratio according to the current speed of the motor; Calculating a motor torque limit value according to the power distribution ratio, and limiting the acquired original output torque of the motor according to the motor torque limit value; The step of calculating the corresponding motor correction speed based on the tire state information and the motor state information, and updating the collected current motor speed according to the motor correction speed includes: When the tire status information indicates that the tire is not slipping and the motor status information indicates that only the front motor speed has failed, calculating a corrected front motor speed using the collected current rear motor speed, and updating the collected current front motor speed based on the corrected front motor speed; When the tire status information indicates that the tire is not slipping and the motor status information indicates that only the rear motor speed has failed, the rear motor correction speed is calculated based on the collected current speed of the front motor, and the collected current speed of the rear motor is updated based on the rear motor correction speed.

2. The motor torque limiting method according to claim 1, characterized in that: The step of calculating a corresponding motor correction speed based on the tire state information and the motor state information, and updating the collected current motor speed according to the motor correction speed also includes: When the tire status information indicates that the tire is not slipping and the motor status information indicates that the front and rear motor speeds are both invalid, a front motor correction speed is calculated based on the collected wheel speed corresponding to the front axle and a preset front motor speed ratio, and the collected current front motor speed is updated based on the front motor correction speed; a rear motor correction speed is calculated based on the collected wheel speed corresponding to the rear axle and a preset rear motor speed ratio, and the collected current rear motor speed is updated based on the rear motor correction speed; The motor correction speed includes at least one of the front motor correction speed and the rear motor correction speed.

3. The motor torque limiting method according to claim 2, characterized in that: The step of calculating a corresponding motor correction speed based on the tire state information and the motor state information, and updating the collected current motor speed according to the motor correction speed also includes: When the tire state information indicates tire slip and the motor state information indicates that both front and rear motor speeds have failed, obtaining a current adhesion coefficient, a current tire slip state, and a wheel speed of the slipping wheel, wherein the current tire slip state indicates one of unilateral slip and bilateral slip; Obtaining a corresponding current speed correction coefficient according to the current adhesion coefficient, the current tire slip state, and a preset mapping relationship, wherein the mapping relationship records the relationship between different tire slip states, adhesion coefficients, and speed correction coefficients; The motor correction speed is obtained according to the product of the slipping wheel speed and the current speed correction coefficient, and the collected current speeds of the front motor and the rear motor are updated according to the motor correction speed.

4. The motor torque limiting method according to claim 3, characterized in that: The step of calculating a corresponding motor correction speed based on the tire state information and the motor state information, and updating the collected current motor speed according to the motor correction speed also includes: When the tire status information indicates tire slippage and the motor status information indicates that only the front motor speed has failed, a first front motor estimated speed is calculated using the collected current speed of the rear motor and a second front motor estimated speed is calculated using the collected current wheel speed of the front motor; the first front motor estimated speed and the second front motor estimated speed are fused and calculated to obtain a corrected front motor speed, and the collected current front motor speed is updated based on the corrected front motor speed; When the tire status information indicates that the tire is slipping and the motor status information indicates that only the rear motor speed has failed, the first rear motor estimated speed is calculated using the collected current speed of the front motor and the second rear motor estimated speed is calculated using the collected current wheel speed of the rear motor; the first rear motor estimated speed and the second rear motor estimated speed are fused and calculated to obtain a corrected rear motor speed, and the collected current rear motor speed is updated based on the corrected rear motor speed.

5. The motor torque limiting method according to claim 4, characterized in that: The step of calculating the second front motor estimated speed based on the collected current wheel speed of the front motor includes: calculating the front motor conversion speed based on the current wheel speed of the front motor and a preset front motor speed ratio; obtaining the second front motor estimated speed based on the product of the front motor conversion speed and the current speed correction coefficient; The step of calculating the estimated speed of the second rear motor by collecting the current wheel speed of the rear motor includes: calculating the conversion speed of the rear motor according to the current wheel speed of the rear motor and the preset rear motor speed ratio; and obtaining the estimated speed of the second rear motor according to the product of the conversion speed of the rear motor and the current speed correction coefficient.

6. The motor torque limiting method according to claim 1, characterized in that: The step of determining the power distribution ratio according to the current speed of the motor includes: Obtain the front motor torque and the rear motor torque; When the current speed of the motor is greater than or equal to a preset threshold, calculating the power distribution ratio according to the front motor torque, the rear motor torque and the current speed of the motor; When the current speed of the motor is less than the preset threshold, calculating the power distribution ratio according to the front motor torque and the rear motor torque; The current motor speed includes the current front motor speed and the current rear motor speed, and the power distribution ratio includes the front motor power distribution ratio and the rear motor power distribution ratio.

7. The motor torque limiting method according to claim 1, characterized in that: The step of calculating a motor torque limit value according to the power distribution ratio and limiting the acquired original output torque of the motor according to the motor torque limit value includes: Calculating a motor torque limit value according to the power distribution ratio, the current motor speed, and a preset motor allowable power, wherein the motor torque limit value includes a front motor torque limit value and a rear motor torque limit value; When the motor torque limit value is a positive value, the minimum value between the motor torque limit value and the original output torque of the motor is used as the final output torque of the motor; When the motor torque limit value is a negative value, the maximum value between the motor torque limit value and the original output torque of the motor is used as the final output torque of the motor.

8. A motor torque limiting device, characterized in that: The device comprises: a state acquisition unit, configured to acquire tire state information and motor state information, wherein the tire state information indicates whether the tire is slipping, and the motor state information indicates whether the motor speed is ineffective; a motor speed correction unit, configured to calculate a corresponding motor speed correction based on the tire state information and the motor state information, and update the collected current motor speed according to the motor speed correction; a power distribution ratio determining unit, configured to determine the power distribution ratio according to the current speed of the motor; a torque limiting unit, configured to calculate a motor torque limit value according to the power distribution ratio, and limit the acquired original output torque of the motor according to the motor torque limit value; Wherein, the motor speed correction unit is specifically used for: When the tire status information indicates that the tire is not slipping and the motor status information indicates that only the front motor speed has failed, calculating a corrected front motor speed using the collected current rear motor speed, and updating the collected current front motor speed based on the corrected front motor speed; When the tire status information indicates that the tire is not slipping and the motor status information indicates that only the rear motor speed has failed, the rear motor correction speed is calculated based on the collected current speed of the front motor, and the collected current speed of the rear motor is updated based on the rear motor correction speed.

9. A vehicle controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the motor torque limiting method according to any one of claims 1 to 7 are implemented.

10. A vehicle, characterized in that: The vehicle includes the vehicle controller according to claim 9.

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