Anti-skid processing method and device of vehicle, vehicle, medium and program product
By monitoring wheel slip ratio and adjusting wheel torque, the problem of brake system wear and deviation caused by wheel slippage on low-traction surfaces in distributed drive vehicles has been solved, achieving higher control accuracy and power performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG GEELY HLDG GRP CO LTD
- Filing Date
- 2022-12-30
- Publication Date
- 2026-05-19
AI Technical Summary
In existing technologies, distributed drive vehicles are prone to wheel slippage on low-traction surfaces, leading to overheating and premature wear of the braking system, low control accuracy, and a tendency for the vehicle to veer off course.
By monitoring the slip ratio of each wheel, and using parameters such as moment of inertia, wheel radius, angular acceleration, slip ratio, and vehicle speed, the target driving torque for each slipping wheel is calculated. Based on the vehicle speed, the target yaw torque is determined, and the wheel torque is adjusted to prevent slippage, avoid brake disc adjustment, reduce wear, and improve control accuracy.
It effectively avoids unnecessary wear on the braking system, improves the accuracy of vehicle control, prevents vehicle deviation, and balances power and handling performance.
Smart Images
Figure CN115946534B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vehicle technology, and more particularly to a method, device, vehicle, medium, and program product for anti-skid treatment of vehicles. Background Technology
[0002] In recent years, new energy vehicles have gained widespread popularity due to their energy efficiency, environmental friendliness, strong power, and comfortable ride. Distributed drive vehicles, employing four wheel-side or four hub motors for independent drive, offer significantly stronger performance compared to centralized drive systems. However, precisely because of their superior power and larger number of drive wheels, distributed drive vehicles are more prone to wheel slippage on low-friction surfaces compared to traditional vehicles. Once slipping, the driving force cannot be increased, and the lateral traction of the wheels decreases, making the vehicle susceptible to skidding, fishtailing, and even serious traffic accidents. Therefore, implementing anti-skid measures for vehicles is a pressing issue that needs to be addressed.
[0003] Currently, anti-skid measures for vehicles primarily involve estimating the road surface adhesion coefficient, then calculating the optimal wheel slip ratio, and controlling the wheel's motion to remain at the optimal slip ratio point, thereby preventing wheel slippage. Specifically, vehicles can use a differential to distribute torque evenly to the two wheels. When one wheel slips and spins freely, the other wheel can only provide the same driving force as the slipping wheel. Therefore, the brakes can increase the driving force of the other wheel by engaging the slipping wheel, thus ensuring that the non-slipping wheel outputs torque and maintaining the wheel slip ratio at the optimal level.
[0004] However, existing technologies suffer from problems such as overheating of the braking system, premature wear, and low control accuracy, leading to vehicle deviation. Summary of the Invention
[0005] This application provides a method, device, vehicle, medium, and program product for anti-skid treatment of vehicles, in order to solve the problems of overheating of the braking system, premature wear, low control accuracy, and vehicle deviation in the prior art.
[0006] In a first aspect, embodiments of this application provide a method for anti-skid treatment of a vehicle, comprising:
[0007] Based on the slip ratio of each wheel of the vehicle and a preset slip ratio, determine whether the vehicle has wheel slippage;
[0008] If the vehicle has wheel slippage, the target driving torque for each slipping wheel is determined by the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel.
[0009] If there are two slipping wheels on the same side, the target yaw torque of the vehicle is determined based on the vehicle speed.
[0010] Based on the vehicle's requested torque, the target yaw torque, and the target drive torque of each slipping wheel, adjust the torque of each wheel.
[0011] In one possible design of the first aspect, adjusting the torque of each wheel based on the requested torque of the vehicle, the target yaw torque, and the target drive torque of each slipping wheel includes:
[0012] Based on the requested torque, determine the requested sub-torque for each wheel;
[0013] Based on the target yaw torque, the requested sub-torque of each slipping wheel, and the target drive torque, adjust the torque of each wheel.
[0014] Optionally, adjusting the torque of each wheel based on the target yaw torque, the requested sub-torque of each slipping wheel, and the target drive torque includes:
[0015] For each slipping wheel, calculate the first difference between the requested sub-torque and the target drive torque of the slipping wheel;
[0016] If the first difference of each slipping wheel is greater than the target yaw torque, then the torque of each non-slipping wheel is increased by half of the target yaw torque, and the torque of each slipping wheel is reduced to the target drive torque of the slipping wheel.
[0017] If the first difference of each slipping wheel is less than or equal to the target yaw torque, then the torque of each non-slipping wheel is increased by half the sum of the first differences of all slipping wheels, and the torque of each slipping wheel is reduced to the target drive torque of the slipping wheel.
[0018] Optionally, determining the requested sub-torque for each wheel based on the requested torque includes:
[0019] Based on the number of wheels of the vehicle, the requested torque is evenly distributed to each wheel to determine the requested sub-torque for each wheel.
[0020] In another possible design of the first aspect, if the vehicle experiences wheel slippage, the target driving torque for each slipping wheel is determined using the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel, including:
[0021] If the vehicle has wheel slippage, the target driving torque for each slipping wheel is determined by the switching torque determined by the constant velocity approach rate, the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel.
[0022] In another possible design of the first aspect, after determining the target driving torque for each slipping wheel by means of the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel if wheel slippage occurs, the method further includes:
[0023] If there is only one slipping wheel, then the requested sub-torque for each wheel is determined based on the requested torque.
[0024] Calculate the second difference between the requested sub-torque and the target drive torque of the slipping wheel;
[0025] The second difference is then evenly distributed to the wheels on the non-slipping axles.
[0026] Secondly, embodiments of this application provide an anti-skid treatment device for a vehicle, comprising:
[0027] The determination module is used to determine whether the vehicle has wheel slippage based on the slip ratio of each wheel and a preset slip ratio;
[0028] The determining module is further configured to determine the target driving torque of each slipping wheel by using the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed and torque of each slipping wheel if the vehicle has wheel slippage.
[0029] The determining module is further configured to determine the target yaw torque of the vehicle based on the vehicle speed if there are two slipping wheels on the same side.
[0030] An adjustment module is used to adjust the torque of each wheel based on the vehicle's requested torque, the target yaw torque, and the target drive torque of each slipping wheel.
[0031] In one possible design of the second aspect, the adjustment module is specifically used for:
[0032] Based on the requested torque, determine the requested sub-torque for each wheel;
[0033] Based on the target yaw torque, the requested sub-torque of each slipping wheel, and the target drive torque, adjust the torque of each wheel.
[0034] Optionally, the adjustment module is specifically used for:
[0035] For each slipping wheel, calculate the first difference between the requested sub-torque and the target drive torque of the slipping wheel;
[0036] If the first difference of each slipping wheel is greater than the target yaw torque, then the torque of each non-slipping wheel is increased by half of the target yaw torque, and the torque of each slipping wheel is reduced to the target drive torque of the slipping wheel.
[0037] If the first difference of each slipping wheel is less than or equal to the target yaw torque, then the torque of each non-slipping wheel is increased by half the sum of the first differences of all slipping wheels, and the torque of each slipping wheel is reduced to the target drive torque of the slipping wheel.
[0038] Optionally, the adjustment module is specifically used for:
[0039] Based on the number of wheels of the vehicle, the requested torque is evenly distributed to each wheel to determine the requested sub-torque for each wheel.
[0040] In another possible design of the second aspect, the determining module is specifically used for:
[0041] If the vehicle has wheel slippage, the target driving torque for each slipping wheel is determined by the switching torque determined by the constant velocity approach rate, the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel.
[0042] In another possible design of the second aspect, after determining the target driving torque for each slipping wheel by means of its moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque if wheel slip occurs in the vehicle, the determining module is further configured to:
[0043] If there is only one slipping wheel, then the requested sub-torque for each wheel is determined based on the requested torque.
[0044] Calculate the second difference between the requested sub-torque and the target drive torque of the slipping wheel;
[0045] The second difference is then evenly distributed to the wheels on the non-slipping axles.
[0046] Thirdly, embodiments of this application provide a vehicle, including: a processor, a memory, and computer program instructions stored in the memory and executable on the processor, wherein the processor executes the computer program instructions to implement the methods provided in the first aspect and various possible designs.
[0047] Fourthly, embodiments of this application may provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods provided in the first aspect and various possible designs.
[0048] Fifthly, embodiments of this application provide a computer program product, including a computer program, which, when executed by a processor, is used to implement the methods provided in the first aspect and various possible designs.
[0049] This application provides a vehicle anti-skid treatment method, device, vehicle, medium, and program product. In this method, the vehicle determines whether wheel slippage exists based on the slip ratio of each wheel and a preset slip ratio. If wheel slippage exists, the target driving torque for each slipping wheel is determined using its moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque. If there are two slipping wheels on the same side, the target yaw torque is determined based on the vehicle speed. The torque of each wheel is adjusted based on the requested torque, the target yaw torque, and the target driving torque of each slipping wheel. This technical solution can monitor the slip ratio of each wheel using a TCS (Traction Control System) and control each wheel individually via a CAN bus. When one wheel or one side of the wheels slips, torque control is applied to the slipping wheel. By reducing the torque of the slipping wheel, the slip ratio of the wheel is adjusted, thus avoiding adjustment of the slip ratio through the brake disc, reducing unnecessary wear on the braking system, increasing its service life, and reducing the need for brake disc and brake pad replacements. Meanwhile, when the vehicle experiences unilateral slippage, the permissible target yaw torque is determined based on the vehicle speed, and the torque of each wheel is reasonably controlled. This balances power and wheel handling performance, improves control accuracy, and prevents the vehicle from veering off course. Attached Figure Description
[0050] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0051] Figure 1 A schematic diagram showing the mapping relationship between wheel slip ratio and adhesion coefficient under different road surfaces;
[0052] Figure 2 A schematic flowchart of an embodiment of the anti-skid treatment method for vehicles provided in this application;
[0053] Figure 3 A schematic diagram illustrating the mapping relationship between vehicle speed and target yaw torque provided for embodiments of this application;
[0054] Figure 4A schematic flowchart of Embodiment 2 of the vehicle anti-skid treatment method provided in this application;
[0055] Figure 5 A schematic flowchart of Embodiment 3 of the vehicle anti-skid treatment method provided in this application;
[0056] Figure 6 This is a schematic diagram of wheel force analysis provided in an embodiment of this application;
[0057] Figure 7 A schematic flowchart of Embodiment 4 of the vehicle anti-skid treatment method provided in this application;
[0058] Figure 8 This is a schematic diagram of the anti-skid treatment device for a vehicle provided in an embodiment of this application.
[0059] The accompanying drawings have illustrated specific embodiments of this disclosure, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this disclosure to those skilled in the art through reference to particular embodiments. Detailed Implementation
[0060] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0061] Before introducing the embodiments of this application, the application background of the embodiments of this application will be explained first:
[0062] Because vehicle skidding can easily lead to skidding, fishtailing, and even serious traffic accidents, anti-skid measures are essential for vehicles.
[0063] Existing technologies mainly employ two methods to prevent vehicle slippage:
[0064] Method 1:
[0065] Figure 1 This diagram illustrates the mapping relationship between wheel slip ratio and adhesion coefficient under different road surface conditions. Figure 1 As shown, on dry concrete pavements, as the wheel slip ratio increases, the longitudinal adhesion coefficient of the vehicle first increases and then decreases, while the lateral adhesion coefficient gradually decreases. Furthermore, the optimal slip ratio varies depending on the pavement type; the optimal slip ratio for icy and snowy pavements is lower than that for dry concrete pavements. Based on... Figure 1As shown, current mainstream traction control systems (TCS) estimate the road surface adhesion coefficient and then calculate the optimal slip ratio to keep the controlled wheel's motion at the optimal slip ratio point, thereby preventing wheel slippage. However, in reality, due to differences in wheel structure, tire tread pattern, wheel usage, wheel speed, and road conditions, the optimal slip ratio also varies. Therefore, identifying the road surface and determining the optimal slip ratio is crucial for the implementation of slip ratio control methods; inaccurate estimation leads to poor vehicle control.
[0066] TCS (Transmission Control System) is commonly found in high-end vehicles, including traditional gasoline-powered cars and direct-drive new energy vehicles. It primarily uses a single electric motor and a differential to distribute torque evenly between the two wheels. This means that if one wheel slips, the other wheel can only provide the same driving force. Therefore, TCS can use the brakes to engage the slipping wheel, increasing the driving force on the other wheel. However, because this method requires simultaneously driving and braking one wheel, it leads to overheating and premature wear of the braking system.
[0067] Method 2:
[0068] TCS reduces the output torque of the engine or motor to below the maximum road surface traction, thus preventing wheel slippage. However, this reduces overall torque and sacrifices power.
[0069] In both of the above methods, under unilateral slippage conditions, the difference in driving force between the left and right wheels will generate yaw torque, causing the high-speed wheels to veer off course and even run into the opposite lane.
[0070] In summary, the existing technology has the following problems:
[0071] 1. It is necessary to estimate the road surface adhesion coefficient in real time and control the wheel slip rate based on this coefficient. However, estimating the road surface adhesion coefficient is a difficult point in the industry. In addition, it is difficult to estimate the road surface adhesion coefficient in real time for roads with large variations, which affects the control effect.
[0072] 2. When a wheel slips, in order to output torque to the non-slipping wheel, the TCS needs to output braking force to the slipping wheel and control the slip ratio, which causes the friction pads to heat up severely and the wheel brake disc and friction pads to wear prematurely.
[0073] 3. When a single wheel slips, whether the yaw torque is reduced or the slipping wheel is controlled by the brake disc, the overall driving force of the vehicle will decrease, resulting in insufficient power.
[0074] 4. When one wheel slips, the TCS will adjust the torque of the slipping wheel. The uneven force on the left and right sides will cause the vehicle to yaw torque, resulting in the vehicle veering to one side.
[0075] Furthermore, for distributed drive systems, because the vehicles are not physically connected, even if a slipping wheel is locked, torque cannot be transferred to the other side. In other words, neither of the above two methods is directly applicable to distributed drive systems. Therefore, for distributed drive systems, a new type of TCS (Traction Control System) needs to be designed to adjust wheel torque based on slippage conditions, controlling the wheel slip ratio appropriately. Simultaneously, it should adjust lateral torque to prevent yaw torque and avoid vehicle deviation.
[0076] Research in related fields has revealed that, since each wheel in a distributed drive system is individually controlled, the slip ratio of a wheel can be controlled by reducing the torque of the slipping wheel. Therefore, this application provides a vehicle anti-skid treatment method, device, vehicle, medium, and program product. The vehicle can determine whether wheel slippage exists based on the slip ratio of each wheel and a preset slip ratio. When slippage occurs and is unilateral, the target driving torque for each slipping wheel is determined using its moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque. This target driving torque is then compared with the vehicle's requested torque. If a difference exists, the torque of each wheel is adjusted based on this difference and the theoretically maximum target yaw torque. This effectively solves problems such as vehicle deviation, overheating of the braking system, and premature wear, improving the accuracy of vehicle control.
[0077] The technical solution of this application will now be described in detail through specific embodiments.
[0078] It should be noted that the following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.
[0079] Figure 2 This is a schematic flowchart of an embodiment of the anti-skid treatment method for vehicles provided in this application. Figure 2 As shown, the anti-skid treatment method for this vehicle may include the following steps:
[0080] S201. Determine whether wheel slippage exists in the vehicle based on the slip ratio of each wheel and the preset slip ratio.
[0081] In this step, since this application aims to prevent further wheel slippage by adjusting the torque of each wheel when wheel slippage occurs, but not when wheel slippage does not occur, it is first necessary to determine whether wheel slippage exists.
[0082] It should be understood that if the slip ratio of a wheel is relatively high, that wheel is likely to be slipping. Therefore, a preset slip ratio can be set according to the performance requirements of the vehicle. If the slip ratio of a wheel is greater than the preset slip ratio threshold, then the wheel is determined to be slipping.
[0083] For example, the slip ratio of a wheel can be calculated using formula (1):
[0084]
[0085] Where slipRate is the slip ratio, w is the wheel speed, v is the vehicle speed, and r is the rolling radius.
[0086] S202. If the vehicle has wheel slippage, the target driving torque for each slipping wheel is determined by the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel.
[0087] In this step, when the vehicle has wheel slippage, the target driving torque of each slipping wheel can be determined by the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel. This target driving torque is the optimal driving torque of the slipping vehicle, which can be understood as the ideal driving torque of the slipping vehicle.
[0088] For example, the target driving torque of the slipping wheel can be calculated using formula (2):
[0089]
[0090] Among them, T meq For the target driving torque, I ω Let λ be the moment of inertia of the wheel, r be the wheel radius, and λ be the slip ratio. Angular acceleration, For torque.
[0091] Optionally, λ can be determined using formula (3):
[0092]
[0093] In one possible implementation, when the system state is outside the sliding surface, to ensure the system state can reach the sliding surface, constant velocity approach rate control can be used to determine the switching torque, and further adjust T based on the switching torque. meq Corrections are made to obtain a more accurate target drive torque. In other words, if wheel slippage occurs, the target drive torque for each slipping wheel is determined by the switching torque determined by the constant velocity approach rate, the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel.
[0094] In this implementation, the switching torque determined by constant velocity approach rate control can be expressed by formula (4):
[0095] T sw =-K sgn(s) Formula (4)
[0096] Among them, T sw For switching torque, K is the approach coefficient, and sgn(s) is the sign of s.
[0097] Furthermore, the corrected target driving torque can be expressed by formula (5). It should be understood that the corrected target driving torque is the target driving torque in this implementation.
[0098]
[0099] Optionally, before S201, formulas (3) and (5) need to be determined in advance. The specific determination process will be described in detail in the following embodiments, and will not be repeated here.
[0100] S203. If there are two slipping wheels on the same side, the target yaw torque of the vehicle is determined based on the vehicle speed.
[0101] In this step, when one wheel of the vehicle slips, the force on the left and right sides of the vehicle is uneven, resulting in inconsistent torque and generating yaw torque. This yaw torque affects the stability of the vehicle, causing it to veer off course, and in severe cases, leading to traffic accidents. Therefore, after confirming that a wheel is slipping, it is necessary to further determine whether it is slipping on only one side and to determine the maximum permissible yaw torque (i.e., the target yaw torque) based on the vehicle's speed, so that the wheel torque can be controlled accordingly in subsequent steps.
[0102] The maximum allowable yaw torque of a vehicle varies at different speeds. At high speeds, the vehicle requires high stability, so a smaller maximum yaw torque is allowed to prevent the vehicle from veering off course or entering oncoming lanes. At low speeds, the driver has greater control and can correct the vehicle's direction by adjusting the steering wheel, preventing dangerous accidents. Therefore, a larger maximum yaw torque can be designed. Also, considering power performance, a larger maximum yaw torque helps the vehicle climb hills. In other words, the maximum allowable yaw torque at different speeds needs to be calibrated based on the vehicle's actual performance.
[0103] In one possible implementation, the mapping relationship between vehicle speed and target yaw torque can be achieved through... Figure 3 To express. Figure 3This is a schematic diagram illustrating the mapping relationship between vehicle speed and target yaw torque provided in an embodiment of this application, as shown below. Figure 3 As shown, the higher the vehicle speed, the smaller the target yaw torque.
[0104] In other words, prior to S201, a yaw torque allowance table could be designed based on vehicle speed. In this yaw torque allowance table, the higher the vehicle speed, the smaller the target yaw torque, and it was even permissible for both left and right wheels to be the same. At low vehicle speeds, the driver has a strong ability to control the vehicle, and the allowable target yaw torque can be appropriately increased.
[0105] S204. Adjust the torque of each wheel according to the vehicle's requested torque, target yaw torque, and target drive torque of each slipping wheel.
[0106] In this step, the requested torque is the torque input by the driver through the accelerator pedal. Based on the requested torque, the target yaw torque, and the target drive torque for each slipping wheel, the torque of the slipping wheel can be reduced, and the torque of the non-slipping wheel can be increased to prevent the wheel from continuing to slip.
[0107] It should be understood that the specific implementation process and principles of S204 can be found by referring to... Figure 4 The embodiments shown are not described in detail here.
[0108] The vehicle anti-skid treatment method provided in this application determines whether wheel slippage exists based on the slip ratio of each wheel and a preset slip ratio. If wheel slippage exists, the target driving torque for each slipping wheel is determined using its moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque. If there are two slipping wheels on the same side, the target yaw torque is determined based on the vehicle speed. The torque of each wheel is adjusted according to the vehicle's requested torque, the target yaw torque, and the target driving torque for each slipping wheel. This technical solution can monitor the slip ratio of each wheel using a TCS (Traction Control System) and control each wheel individually via a CAN bus. When one wheel or one side of the wheels slips, torque control is applied to the slipping wheel. By reducing the torque of the slipping wheel, the slip ratio is adjusted, thus avoiding adjustment of the slip ratio through the brake disc, reducing unnecessary wear on the braking system, increasing its service life, and reducing the need for brake disc and brake pad replacements. Meanwhile, when the vehicle experiences unilateral slippage, the permissible target yaw torque is determined based on the vehicle speed, and the torque of each wheel is reasonably controlled. This balances power and wheel handling performance, improves control accuracy, and prevents the vehicle from veering off course.
[0109] based on Figure 2 The embodiment shown will now be further explained in detail below. Figure 4 This is a schematic flowchart of Embodiment 2 of the vehicle anti-skid treatment method provided in this application. Figure 4 As shown, S204 may include the following steps:
[0110] S401. Determine the requested sub-torque for each wheel based on the requested torque.
[0111] In this step, after the vehicle receives the requested torque input by the user through the accelerator pedal, it can determine the requested sub-torque for each wheel based on the requested torque.
[0112] In one possible implementation, the requested torque can be evenly distributed to each wheel based on the number of wheels of the vehicle, thereby determining the requested sub-torque for each wheel.
[0113] For example, assuming the requested torque is Freq, the requested sub-torque for each wheel can be expressed by formula (6):
[0114] Fw=Freq / 4 Formula (6)
[0115] Where Fw is the requested sub-torque.
[0116] S402. Adjust the torque of each wheel according to the target yaw torque, the requested sub-torque of each slipping wheel, and the target drive torque.
[0117] In this step, the available torque difference can be calculated based on the requested sub-torque of the slipping wheel and the target drive torque, and the wheel can be controlled based on this torque difference and the target yaw torque.
[0118] In one possible implementation, S302 can be achieved through steps (1)-(3):
[0119] Step (1): For each slipping wheel, calculate the first difference between the requested sub-torque of the slipping wheel and the target drive torque. This first difference is the available torque difference mentioned above.
[0120] For example, the first difference can be expressed by formula (7):
[0121] Fdif=Freq / 4-Fact formula (7)
[0122] Where Fact is the target driving torque, which is T m and T sw Another way to express it.
[0123] Step (2): If the first difference of each slipping wheel is greater than the target yaw torque, increase the torque of each non-slipping wheel by half of the target yaw torque, and reduce the torque of each slipping wheel to the target drive torque of the slipping wheel.
[0124] For example, suppose the slipping wheels are Fw2 and Fw4, with corresponding target yaw torques of Fact2 and Fact4, and the vehicle's target yaw torque is FdifAlow. Comparing Freq / 4 - Fact2 with FdifAlow and Freq / 4 - Fact4 with FdifAlow, if Freq / 4 - Fact2 is greater than FdifAlow and Freq / 4 - Fact4 is greater than FdifAlow, directly distributing the first difference equally between Fw2 and Fw4 would result in a yaw torque greater than the target yaw torque, leading to vehicle instability. Therefore, the non-slipping wheels (Fw1 and Fw3) can be adjusted to Freq / 4 + FdifAlow / 2, while the slipping wheels (Fw2 and Fw4) can be adjusted to the target yaw torque. This ensures that the vehicle's yaw torque does not exceed the target yaw torque while maintaining the vehicle's power performance and stability.
[0125] Step (3): If the first difference of each slipping wheel is less than or equal to the target yaw torque, then increase the torque of each non-slipping wheel by half the sum of the first differences of all slipping wheels, and reduce the torque of each slipping wheel to the target drive torque of the slipping wheel.
[0126] For example, suppose the slipping wheels are Fw2 and Fw4, and their corresponding target yaw torques are Fact2 and Fact4, respectively. The vehicle's target yaw torque is FdifAlow. When Freq / 4 - Fact2 is less than or equal to FdifAlow, and Freq / 4 - Fact4 is less than or equal to FdifAlow, it means that the available torque difference is less than or equal to the target yaw torque. The non-slipping wheels (Fw1 and Fw3) can be directly adjusted to Freq / 4 + (Freq / 4 - Fact2 + Freq / 4 - Fact4) / 2, while the slipping wheels (Fw2 and Fw4) are adjusted to the target yaw torque.
[0127] In the above embodiment, the available torque difference is calculated based on the requested sub-torque of the slipping wheel and the target driving torque, and the target yaw torque is determined based on the vehicle speed. The available torque difference is then transferred to the non-slipping wheel. This ensures that the vehicle does not veer off course, thereby maximizing the vehicle's climbing ability and power performance, ensuring the rationality of torque control for each wheel, and balancing the vehicle's power and the wheel's handling performance.
[0128] The above embodiments have specifically described the process and principle of controlling wheel torque when two wheels are slipping and are on the same side. However, in practical applications, there may be situations where only one wheel of the vehicle slips, in which case anti-skid measures are also required.
[0129] Based on any of the above embodiments Figure 5 This is a flowchart illustrating Embodiment 3 of the vehicle anti-skid treatment method provided in this application. Figure 5 As shown, after S202, the anti-skid treatment method for this vehicle may also include the following steps:
[0130] S501. If there is only one slipping wheel, then determine the requested sub-torque for each wheel based on the requested torque.
[0131] It should be understood that the determination of the requested sub-torque for each wheel in this step, based on the requested torque, can be referred to the relevant content in S401, and will not be repeated here.
[0132] S502, Calculate the second difference between the requested sub-torque of the slipping wheel and the target drive torque.
[0133] In this step, after calculating the requested sub-torque for each wheel, it means that the requested sub-torque for the slipping wheel has been determined. Therefore, the available torque difference for the slipping wheel can be calculated based on the requested sub-torque of the slipping wheel and the target drive torque.
[0134] It should be understood that the specific implementation method and implementation principle of this step can be referred to the relevant content of step (2) of S402, and will not be repeated here.
[0135] S503, Distribute the second difference equally to the wheels of the non-slipping axle.
[0136] In this step, to suppress further slippage of the slipping wheel, the available torque difference (second difference) can be evenly distributed to the wheels on the non-slipping axle. At this point, the torque of each wheel on the non-slipping axle is adjusted to the sum of the allocated portion of the second difference (i.e., half of the second difference) and the requested sub-torque. In other words, the torque of each non-slipping wheel is adjusted to Fw + (Freq / 4 - Fact) / 2.
[0137] In the above embodiments, after a single wheel of the vehicle slips, the torque is promptly transferred to the non-slipping axle, the overall vehicle power remains unchanged, there is no sudden torque change, and the ride comfort is improved.
[0138] Optionally, this application may also pre-design a drive anti-slip film controller, which includes formulas (3) and (5) for determining the target drive torque of the slipping wheel.
[0139] The specific design process of the anti-slip diaphragm controller is as follows:
[0140] As an important component of vehicle dynamics models, wheel models mainly describe wheel motion through two parts: torque balance equations and vertical loads. Figure 6This is a schematic diagram of wheel force analysis provided for an embodiment of this application. Figure 6 As shown, ignoring the effect of rolling resistance, the wheel torque balance equation during driving can be expressed by formula (8):
[0141]
[0142] Among them, T d For driving torque, F x This is the longitudinal force acting on the wheel.
[0143] When the vehicle is stationary, the wheels bear the weight of the vehicle body and all components integrated into the body; at this time, the vertical load borne by the wheels is a static load. When the vehicle is in motion, the vertical load borne by the wheels will change due to the influence of suspension characteristics, driver operation, and road surface disturbances, and the vertical load borne by each wheel will be different. However, obtaining the suspension characteristics and road surface disturbances is relatively difficult. Therefore, in the research process, the influence of inertial drag torque, air lift, suspension and road surface characteristics on the vertical load of the wheels is ignored. Then, the vertical load of each wheel can be expressed by formula (9):
[0144]
[0145] Among them, l r l f These are the distances from the center of mass to the rear axle and the front axle, respectively, a x a y These represent the longitudinal and lateral accelerations, respectively, where g is the acceleration due to gravity, and h is the acceleration due to gravity. g Where m is the vehicle's center of gravity height, l is the curb weight, and d is the wheelbase.
[0146] The longitudinal force of the wheel can be expressed by formula (10):
[0147]
[0148] The first derivative of formula (3) can be expressed by formula (11):
[0149]
[0150] When designing the sliding surface of the anti-slip controller, the two forms shown in formula (12) are generally adopted:
[0151]
[0152] Among them, China Here, s is a positive constant, e is the slip ratio error, and λ is a negative constant. opt This represents the optimal slip ratio.
[0153] The slip ratio error can be expressed by formula (13):
[0154] e = λ - λ opt Formula (13)
[0155] The design of the sliding surface can be expressed by formula (14):
[0156] s=λ-λ opt Formula (14)
[0157] By employing equivalent control plus switching control, the sliding mode control exhibits better robustness to modeling uncertainties and other disturbances. The control quantity of the system is then expressed by formula (15):
[0158] u = u eq +u sw Formula (15)
[0159] Where u is the control variable of the system, u eq For theoretical calculation of control quantity, u sw This is the amount of synovial control.
[0160] Equivalent control appears At this time, the optimal transfer rate λ opt It can be assumed to be a constant, that is Formula (3) can be obtained from equations (10) and (11).
[0161] Furthermore, formula (5) satisfies formulas (16) and (17):
[0162]
[0163] In the formula, η is the approach rate, which is greater than 0 and is a constant.
[0164]
[0165] Based on the anti-skid treatment method for vehicles shown in any of the above embodiments, the method will be illustrated by a specific example below.
[0166] Figure 7 This is a schematic flowchart of Embodiment 4 of the vehicle anti-skid treatment method provided in this application. Figure 7 As shown, the anti-skid treatment method for this vehicle includes:
[0167] Step 1: Determine whether the vehicle has wheel slippage based on the slip ratio of each wheel and the preset slip ratio.
[0168] Step 2: If the vehicle has wheel slippage, the target drive torque for each slipping wheel is determined by the slippage drive anti-slip film controller.
[0169] Step 3: Determine the slippage status of all four wheels. If only one wheel is slipping, proceed to step 4; if only one wheel is slipping, proceed to step 6.
[0170] Step 4: Calculate the second difference between the requested sub-torque of the slipping wheel and the target drive torque, then proceed to Step 5.
[0171] Step 5: Distribute the second difference evenly to the wheels of the non-slipping axle, and then end the adjustment of the vehicle torque.
[0172] Step 6: Determine the target yaw torque of the vehicle based on the vehicle speed, and then proceed to Step 7.
[0173] Step 7: For each slipping wheel, calculate the first difference between the requested sub-torque and the target drive torque of the slipping wheel, and then proceed to Step 8.
[0174] Step 8: Determine if the first difference of each slipping wheel is greater than the target yaw torque. If so, proceed to step 9; otherwise, proceed to step 10.
[0175] Step 9: Increase the torque of each non-slipping wheel by half of the target yaw torque, and reduce the torque of each slipping wheel to the target drive torque of the slipping wheel. Then, the adjustment of the vehicle torque is complete.
[0176] Step 10: Increase the torque of each non-slipping wheel by half the sum of the first differences of all slipping wheels, reduce the torque of each slipping wheel to the target drive torque of the slipping wheel, and then end the adjustment of the vehicle torque.
[0177] The following are embodiments of the apparatus described in this application, which can be used to execute the embodiments of the method described in this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the method described in this application.
[0178] Figure 8 This is a schematic diagram of the anti-skid treatment device for a vehicle provided in an embodiment of this application. Figure 8 As shown, the anti-skid treatment device 800 of the vehicle includes:
[0179] The determination module 801 is used to determine whether the vehicle has wheel slippage based on the slip ratio of each wheel and a preset slip ratio.
[0180] The determination module 801 is also used to determine the target driving torque of each slipping wheel by using the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed and torque of each slipping wheel if wheel slippage occurs in the vehicle.
[0181] The determination module 801 is also used to determine the target yaw torque of the vehicle based on the vehicle speed if there are two slipping wheels on the same side.
[0182] The adjustment module 802 is used to adjust the torque of each wheel according to the vehicle's requested torque, the target yaw torque, and the target drive torque of each slipping wheel.
[0183] In one possible design of this application embodiment, the adjustment module 802 is specifically used for:
[0184] Based on the requested torque, determine the requested sub-torque for each wheel.
[0185] Adjust the torque of each wheel based on the target yaw torque, the requested sub-torque of each slipping wheel, and the target drive torque.
[0186] Optionally, adjustment module 802 is specifically used for:
[0187] For each slipping wheel, calculate the first difference between the requested sub-torque of the slipping wheel and the target drive torque.
[0188] If the first difference of each slipping wheel is greater than the target yaw torque, then increase the torque of each non-slipping wheel by half of the target yaw torque, and reduce the torque of each slipping wheel to the target drive torque of the slipping wheel.
[0189] If the first difference of each slipping wheel is less than or equal to the target yaw torque, then the torque of each non-slipping wheel is increased by half the sum of the first differences of all slipping wheels, and the torque of each slipping wheel is reduced to the target drive torque of the slipping wheel.
[0190] Optionally, adjustment module 802 is specifically used for:
[0191] Based on the number of wheels of the vehicle, the requested torque is evenly distributed to each wheel to determine the requested sub-torque for each wheel.
[0192] In another possible design of this application embodiment, the determining module 801 is specifically used for:
[0193] If the vehicle has wheel slippage, the target driving torque for each slipping wheel is determined by the switching torque determined by the constant velocity approach rate, the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel.
[0194] In another possible design of this application embodiment, if wheel slippage occurs in the vehicle, after determining the target driving torque for each slipping wheel based on its moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque, the determining module 801 is further configured to:
[0195] If there is only one slipping wheel, then the requested sub-torque for each wheel is determined based on the requested torque.
[0196] Calculate the second difference between the requested sub-torque of the slipping wheel and the target drive torque.
[0197] The second difference is then evenly distributed among each non-slipping wheel.
[0198] The anti-skid treatment device for vehicles provided in this application embodiment can be used to perform the anti-skid treatment method for vehicles in any of the above embodiments. Its implementation principle and technical effect are similar, and will not be described again here.
[0199] It should be noted that the division of the various modules in the above device is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, these modules can be implemented entirely in software via processing element calls; they can be fully implemented in hardware; or some modules can be implemented by processing element calls to software, while others are implemented in hardware. Additionally, these modules can be fully or partially integrated together, or implemented independently. The processing element mentioned here can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each of the above modules can be completed through the integrated logic circuits in the hardware of the processor element or through software instructions.
[0200] This application provides a vehicle that may include a processor, a memory, and computer program instructions stored in the memory and executable on the processor. When the processor executes the computer program instructions, it implements the anti-skid treatment method for the vehicle provided in any of the foregoing embodiments.
[0201] The vehicle can be driven by four motors, three motors, or two motors, depending on the actual situation. This application does not impose specific restrictions on this.
[0202] Optionally, the various components of the vehicle can be connected via a system bus.
[0203] Memory can be a separate storage unit or a storage unit integrated into the processor. There can be one or more processors.
[0204] Optionally, the vehicle may also include interfaces for interacting with other devices.
[0205] It should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. A general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this application can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.
[0206] The system bus can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The system bus can be divided into address bus, data bus, control bus, etc. For ease of representation, only one thick line is used in the diagram, but this does not indicate that there is only one bus or one type of bus. Memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.
[0207] All or part of the steps in the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a readable memory. When the program is executed, it performs the steps of the above-described method embodiments; and the aforementioned memory (storage medium) includes: read-only memory (ROM), RAM, flash memory, hard disk, solid-state drive, magnetic tape, floppy disk, optical disk, and any combination thereof.
[0208] The vehicle provided in this application embodiment can be used to perform the anti-skid treatment method for the vehicle provided in any of the above method embodiments. The implementation principle and technical effect are similar, and will not be repeated here.
[0209] This application provides a computer-readable storage medium storing computer instructions that, when executed on a computer, cause the computer to perform the aforementioned anti-skid treatment method for vehicles.
[0210] The aforementioned computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory, electrically erasable programmable read-only memory, erasable programmable read-only memory, programmable read-only memory, read-only memory, magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.
[0211] Optionally, a readable storage medium can be coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Alternatively, the readable storage medium can be an integral part of the processor. Both the processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components within the device.
[0212] This application also provides a computer program product, which includes a computer program stored in a computer-readable storage medium. At least one processor can read the computer program from the computer-readable storage medium, and when the at least one processor executes the computer program, it can implement the above-mentioned anti-skid treatment method for vehicles.
[0213] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.
Claims
1. A method for preventing skidding on a vehicle, characterized in that, include: Based on the slip ratio of each wheel of the vehicle and a preset slip ratio, determine whether the vehicle has wheel slippage; If the vehicle has wheel slippage, the target driving torque for each slipping wheel is determined by the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel. If there are two slipping wheels on the same side, the target yaw torque of the vehicle is determined based on the vehicle speed. Based on the vehicle's requested torque, the target yaw torque, and the target drive torque of each slipping wheel, adjust the torque of each wheel. If the number of slipping wheels is one, then the requested sub-torque for each wheel is determined based on the requested torque; Calculate the second difference between the requested sub-torque and the target drive torque of the slipping wheel; The second difference is then evenly distributed to the wheels on the non-slipping axles.
2. The method according to claim 1, characterized in that, The step of adjusting the torque of each wheel based on the requested torque of the vehicle, the target yaw torque, and the target drive torque of each slipping wheel includes: Based on the requested torque, determine the requested sub-torque for each wheel; Based on the target yaw torque, the requested sub-torque of each slipping wheel, and the target drive torque, adjust the torque of each wheel.
3. The method according to claim 2, characterized in that, The step of adjusting the torque of each wheel based on the target yaw torque, the requested sub-torque of each slipping wheel, and the target drive torque includes: For each slipping wheel, calculate the first difference between the requested sub-torque and the target drive torque of the slipping wheel; If the first difference of each slipping wheel is greater than the target yaw torque, then the torque of each non-slipping wheel is increased by half of the target yaw torque, and the torque of each slipping wheel is reduced to the target drive torque of the slipping wheel. If the first difference of each slipping wheel is less than or equal to the target yaw torque, then the torque of each non-slipping wheel is increased by half the sum of the first differences of all slipping wheels, and the torque of each slipping wheel is reduced to the target drive torque of the slipping wheel.
4. The method according to claim 2 or 3, characterized in that, The step of determining the requested sub-torque for each wheel based on the requested torque includes: Based on the number of wheels of the vehicle, the requested torque is evenly distributed to each wheel to determine the requested sub-torque for each wheel.
5. The method according to any one of claims 1 to 3, characterized in that, If the vehicle experiences wheel slippage, the target driving torque for each slipping wheel is determined based on its moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque, including: If the vehicle has wheel slippage, the target driving torque for each slipping wheel is determined by the switching torque determined by the constant velocity approach rate, the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel.
6. A vehicle anti-skid treatment device, characterized in that, include: The determination module is used to determine whether the vehicle has wheel slippage based on the slip ratio of each wheel and a preset slip ratio; The determining module is further configured to determine the target driving torque of each slipping wheel by using the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed and torque of each slipping wheel if the vehicle has wheel slippage. The determining module is further configured to determine the target yaw torque of the vehicle based on the vehicle speed if there are two slipping wheels on the same side. An adjustment module is used to adjust the torque of each wheel according to the requested torque of the vehicle, the target yaw torque, and the target drive torque of each slipping wheel; The determining module is further configured to: if the number of slipping wheels is one, determine the requested sub-torque of each wheel based on the requested torque; Calculate the second difference between the requested sub-torque and the target drive torque of the slipping wheel; The second difference is then evenly distributed to the wheels on the non-slipping axles.
7. The apparatus according to claim 6, characterized in that, The adjustment module is specifically used for: Based on the requested torque, determine the requested sub-torque for each wheel; Based on the target yaw torque, the requested sub-torque of each slipping wheel, and the target drive torque, adjust the torque of each wheel.
8. The apparatus according to claim 7, characterized in that, The adjustment module is specifically used for: For each slipping wheel, calculate the first difference between the requested sub-torque and the target drive torque of the slipping wheel; If the first difference of each slipping wheel is greater than the target yaw torque, then the torque of each non-slipping wheel is increased by half of the target yaw torque, and the torque of each slipping wheel is reduced to the target drive torque of the slipping wheel. If the first difference of each slipping wheel is less than or equal to the target yaw torque, then the torque of each non-slipping wheel is increased by half the sum of the first differences of all slipping wheels, and the torque of each slipping wheel is reduced to the target drive torque of the slipping wheel.
9. The apparatus according to claim 7 or 8, characterized in that, The adjustment module is specifically used for: Based on the number of wheels of the vehicle, the requested torque is evenly distributed to each wheel to determine the requested sub-torque for each wheel.
10. The apparatus according to any one of claims 6 or 8, characterized in that, The determining module is specifically used for: If the vehicle has wheel slippage, the target driving torque for each slipping wheel is determined by the switching torque determined by the constant velocity approach rate, the moment of inertia, wheel radius, angular acceleration, slip ratio, vehicle speed, and torque of each slipping wheel.
11. A vehicle comprising: A processor, a memory, and computer program instructions stored in the memory and executable on the processor, characterized in that the processor executes the computer program instructions to implement the anti-skid treatment method for a vehicle as described in any one of claims 1 to 5.
12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the anti-skid treatment method for a vehicle as described in any one of claims 1 to 5.
13. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it is used to implement the anti-skid treatment method for a vehicle as described in any one of claims 1 to 5.