A method for controlling slippage of electric two-wheeled vehicles considering road surface slippage

Abstract

This application discloses a slip control method for electric two-wheelers that takes into account the degree of road slippage, relating to the field of vehicle technology. When slippage is detected in the electric two-wheeler, the method first controls the motor to work according to a predetermined negative torque to quickly suppress slippage. The road slippage coefficient is determined based on the driving state parameters of the electric two-wheeler when slippage occurs. Then, after the predetermined negative torque control of the motor reaches a predetermined condition, the method proceeds to the second stage, starting from the initial given torque, increasing the torque in increments according to the torque increments in control cycles and controlling the motor to work. The larger the road slippage coefficient, the higher the degree of road slippage, and the smaller the determined torque increment. This achieves the effect of slowly increasing torque on slippery roads to avoid slippage again, and rapidly increasing torque on relatively non-slippery roads to avoid jerking. This ensures the smoothness of the electric two-wheeler's driving and optimizes the riding experience.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a method for controlling the slippage of an electric two-wheeled vehicle that takes into account the degree of road slippage. Background Technology

[0002] Electric two-wheelers are prone to slippage during start-up, acceleration, and on slippery surfaces. To reduce safety issues caused by slippage, electric two-wheelers typically use a traction control system (TCS) for slippage control. The core idea is that when the speed difference between the drive wheel and the driven wheel exceeds a set value, slippage is considered to have occurred. At this point, torque is calculated based on the speed difference and distributed to the drive wheel, thus reducing torque to suppress slippage. However, the road conditions for electric two-wheelers are varied, and simply reducing torque can easily cause a jerking sensation, affecting the ride stability and passenger experience. Summary of the Invention

[0003] This application addresses the aforementioned problems and technical requirements by proposing a method for controlling the slippage of electric two-wheeled vehicles that takes into account the degree of road surface slippage. The technical solution of this application is as follows:

[0004] A method for controlling the slippage of an electric two-wheeled vehicle that takes into account the degree of road surface slippage, the method comprising:

[0005] When slippage is detected in an electric two-wheeled vehicle, the road slippage coefficient k is determined based on the vehicle's driving state parameters at the time of slippage, and a predetermined negative torque T is applied. r Control the motor to work; among them, the larger the road surface slip coefficient k, the higher the degree of road surface slipperiness;

[0006] The torque increment T is determined based on the road surface slip coefficient k. d The larger the road surface slip coefficient k, the greater the torque increment T. d The smaller;

[0007] According to the predetermined negative torque T r After the motor operates under predetermined conditions, starting from the initial given torque T1, control cycles are performed according to the torque increment T. d Increase torque and control motor operation.

[0008] A further technical solution is that the slippage control method for electric two-wheeled vehicles also includes:

[0009] According to the predetermined negative torque T r When the motor operates for a slippage suppression time t, or when the driving speed of the electric two-wheeler is detected to be lower than the speed threshold, the predetermined negative torque T is determined.r The motor is controlled to operate under predetermined conditions; otherwise, it is determined that the predetermined conditions have not yet been met.

[0010] A further technical solution is that the slippage control method for electric two-wheeled vehicles also includes:

[0011] The slippage suppression time t is determined based on the road surface slippage coefficient k. The larger the road surface slippage coefficient k, the smaller the slippage suppression time t.

[0012] The further technical solution is that the initial given torque T1 is greater than 0.

[0013] A further technical solution is that the slippage control method for electric two-wheeled vehicles also includes:

[0014] The initial torque T1 is determined based on the road surface slip coefficient k. The larger the road surface slip coefficient k, the smaller the initial torque T1.

[0015] A further technical solution is that the slippage control method for electric two-wheeled vehicles also includes:

[0016] During the operation of the electric two-wheeled vehicle, the speed of the drive wheels is collected by a speed sensor installed on the drive wheels, and the vehicle is used to detect whether the vehicle is slipping based on the speed of the drive wheels.

[0017] A further technical solution involves detecting whether the electric two-wheeler is slipping based on the speed of the drive wheels, including:

[0018] The drive wheel acceleration 'a' is determined based on the drive wheel speeds of the current and previous control cycles. When the drive wheel acceleration 'a' reaches the acceleration threshold 'a' during the operation of the electric two-wheeled vehicle... th At that time, it was determined that the electric two-wheeled vehicle was slipping.

[0019] A further technical solution involves determining the road surface slip coefficient k based on the driving state parameters of the electric two-wheeled vehicle when slippage occurs, including:

[0020] The slip coefficient lookup table is used to determine the drive wheel acceleration *a* and motor torque *T* when slippage occurs on an electric two-wheeled vehicle. e The corresponding road surface slip coefficient k;

[0021] Among them, the slip coefficient lookup table is pre-established, and the motor torque T is obtained under the same drive wheel acceleration a. e The smaller the value, the larger the corresponding road surface slip coefficient k. For the same motor torque T, e The greater the acceleration 'a' of the lower drive wheel, the greater the corresponding road surface slip coefficient 'k'.

[0022] A further technical solution is that the slippage control method for electric two-wheeled vehicles also includes:

[0023] Starting from the initial given torque T1, control cycles are performed according to the torque increment T. d Increase the torque and control the motor to work until slippage of the electric two-wheeler is detected again, or until the maximum torque is reached and the motor is controlled to work at the maximum torque.

[0024] The beneficial technical effects of this application are:

[0025] This application discloses a slip control method for electric two-wheelers that takes into account the degree of road slippage. When slippage is detected, the method controls the vehicle in two stages. In the first stage, a given negative torque is applied to quickly suppress slippage, and the road slippage coefficient is determined based on the driving state parameters of the electric two-wheeler when slippage occurs. Then, the torque increment matching the degree of road slippage can be determined based on the road slippage coefficient. In the second stage, the torque is increased according to the torque increment matching the degree of road slippage. This achieves the effect of slowly increasing torque on slippery roads to avoid slippage again, and rapidly increasing torque on relatively dry roads to avoid jerking. This ensures the smoothness of the electric two-wheeler and optimizes the riding experience.

[0026] The initial torque given in the second stage of this method is not fixed to start from 0, which can improve vehicle response. In addition, the duration of the first stage is also determined according to the road slip coefficient to match the road slipness. The initial torque given in the second stage is also determined according to the road slip coefficient to match the road slipness. This makes the entire slip control process based on the road slipness, which can better adapt to the slip control needs of different road slipness levels and ensure the driving stability and riding experience of electric two-wheelers.

[0027] This method uses the acceleration of the drive wheel to detect whether the electric two-wheeler is slipping. It eliminates the need to install a speed sensor on the driven wheel, which reduces the number of components used, thus reducing computation and lowering costs. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating an embodiment of an electric two-wheeled vehicle slippage control method according to this application.

[0029] Figure 2 This is a torque-time curve for an example. Detailed Implementation

[0030] The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0031] This application discloses a method for controlling the slippage of an electric two-wheeled vehicle that takes into account the degree of road slippage. Please refer to [reference needed]. Figure 1 The flowchart shown illustrates the following steps in the electric two-wheeler slip control method:

[0032] Step 1: Detect whether the electric two-wheeler slips while it is in motion.

[0033] Traditional methods detect slippage in electric two-wheelers by detecting the speed difference between the drive and driven wheels. This method requires speed sensors on both the drive and driven wheels, necessitating the use of multiple sensors and resulting in high computational complexity. To avoid this problem, in one embodiment, during the electric two-wheeler's operation, a speed sensor located on the drive wheel collects the drive wheel's speed, and slippage is detected based on this speed. In other words, in this embodiment, only the drive wheel needs a speed sensor, eliminating the need for sensors on the driven wheels. Detecting slippage based on drive wheel speed includes:

[0034] The fundamental reason for slippage in electric two-wheeled vehicles is the low friction between the tires and the ground on slippery surfaces. However, the driving force of the motor is relatively high compared to this friction. Therefore, according to Newton's second law of motion, when slippage occurs, the wheel acceleration increases sharply in a short period of time. Thus, after detecting the drive wheel speed in each control cycle, the drive wheel acceleration 'a' is determined based on the drive wheel speed in the current control cycle and the previous control cycle. When the drive wheel acceleration 'a' reaches the acceleration threshold 'a' during the electric two-wheeled vehicle's operation... th At that time, it was determined that the electric two-wheeled vehicle was slipping. The acceleration threshold a was... th It can be pre-calibrated and determined.

[0035] If no slippage is detected, continue driving in the current state. If slippage is detected in the electric two-wheeler, proceed to step 2 below.

[0036] Step 2: When slippage of the electric two-wheeler is detected, determine the road slippage coefficient k based on the driving state parameters of the electric two-wheeler when slippage occurs, and apply the predetermined negative torque T. r Controlling the motor's operation, wherein the predetermined negative torque T r This is a negative torque, and the specific torque value can be pre-calibrated. Upon detecting slippage, it first switches to the predetermined negative torque T. r It can quickly suppress wheel slippage, preventing the vehicle from continuing to slip for a period of time due to the presence of positive torque when slipping.

[0037] The driving parameters of an electric two-wheeler when slippage occurs include the acceleration 'a' of the drive wheel and the torque 'T' of the motor when slippage occurs. eDetermining the road slip coefficient k based on driving state parameters includes: consulting a slip coefficient lookup table to determine the drive wheel acceleration a and motor torque T when slippage occurs with the electric two-wheeler. e The corresponding road surface slip coefficient k. The larger the determined road surface slip coefficient k, the higher the degree of road surface slipperiness.

[0038] Since the wheel radius and overall mass of the electric two-wheeler are known, the slip coefficient lookup table can be pre-established. In the established slip coefficient lookup table, the motor torque T under the same drive wheel acceleration 'a'... e The smaller the value, the lower the road surface adhesion coefficient, the more slippery the surface, and the larger the corresponding road surface slip coefficient k. For the same motor torque T... e The greater the acceleration 'a' of the lower drive wheel, the lower the road surface adhesion coefficient and the more slippery the surface, and the greater the corresponding road surface slip coefficient 'k'.

[0039] Step 3: Determine the torque increment T based on the road surface slip coefficient k. d The larger the road surface slip coefficient k, the greater the torque increment T will be. d The smaller the value, the lower the coefficient of slip k and the torque increment T. d The correspondence can be pre-built and set.

[0040] Step 4, according to the predetermined negative torque T r After the motor operates under predetermined conditions, starting from the initial given torque T1, control cycles are performed according to the torque increment T. d Increase torque and control motor operation.

[0041] In one embodiment, according to a predetermined negative torque T r When the motor operates for a slippage suppression time t, or when the driving speed of the electric two-wheeler is detected to be lower than the speed threshold, the predetermined negative torque T is determined. r The control motor operates until a predetermined condition is met; otherwise, it is determined that the predetermined condition has not yet been met. The slippage suppression time t can be a fixed empirical value, or, for better slippage suppression, it can be determined based on the road surface slippage coefficient k. The larger the road surface slippage coefficient k, i.e., the wetter the road surface, the smaller the slippage suppression time t.

[0042] In the second torque processing stage, the initial given torque T1 is not fixed at 0, but is a value greater than 0. This avoids the vehicle response delay caused by the torque being added back from 0, thus improving the response speed. Furthermore, this initial given torque T1 is not a fixed value, but is matched to the road surface slippage. In one embodiment, the initial given torque T1 is determined according to the road surface slippage coefficient k. The larger the road surface slippage coefficient k, the smaller the initial given torque T1.

[0043] That is, the slip control of this application after detecting slippage in the electric two-wheeled vehicle is divided into two stages. The first stage is based on a predetermined negative torque T. r The second stage is the torque processing stage, which quickly suppresses slippage and adjusts the torque increment T according to the degree of road surface slippage. d Increasing torque, a torque-time curve in one example is as follows Figure 2 As shown, in Figure 2 During the period from 0 to t1, the electric two-wheeler operates normally, and the motor torque continuously increases. At time t1, the motor torque is T. e The system detected slippage in the electric two-wheeler and switched to a predetermined negative torque T with a negative value. r At time t2, the predetermined negative torque T is determined. r If the control motor operates until the slippage suppression time t is reached, then starting from the initial given torque T1 corresponding to the road slippage coefficient k, the torque increment T corresponding to the road slippage coefficient k will be applied. d Increase torque. During the torque processing stage, the larger the road surface slip coefficient k, meaning the higher the road surface slipperiness, the more important it is to adjust the initial torque T1 and the torque increment T. d If both are relatively small, the torque is gradually increased from a small initial torque T1 to prevent the electric two-wheeler from slipping sharply again on the wet road surface. Conversely, when the road surface slip coefficient k is smaller, indicating a less slippery surface, the initial torque T1 and torque increment T... d Both are relatively large to achieve a rapid increase in torque, avoiding the noticeable jerking that occurs when the torque of an electric two-wheeler increases slowly. This results in smooth operation and optimized user experience under various road surface conditions.

[0044] Starting from the initial given torque T1, control cycles are performed according to the torque increment T. d Increase the torque and control the motor to work until slippage of the electric two-wheeler is detected again, then repeat steps 2-4, or continue to control the motor to work at the maximum torque until the maximum torque is reached.

[0045] The above descriptions are merely preferred embodiments of this application, and this application is not limited to the above embodiments. It is understood that other improvements and variations that can be directly derived or conceived by those skilled in the art without departing from the spirit and concept of this application should be considered to be included within the protection scope of this application.

Claims

1. A method for controlling the slippage of an electric two-wheeled vehicle considering the degree of road surface slippage, characterized in that, The method for controlling slippage in the electric two-wheeled vehicle includes: When slippage is detected in an electric two-wheeled vehicle, the road slippage coefficient k is determined based on the vehicle's driving state parameters at the time of slippage, and a predetermined negative torque T is applied. r Control the motor to work; among them, the larger the road surface slip coefficient k, the higher the degree of road surface slipperiness; The torque increment T is determined based on the road surface slip coefficient k. d The larger the road surface slip coefficient k, the greater the torque increment T. d The smaller; According to the predetermined negative torque T r After the motor operates under predetermined conditions, starting from the initial given torque T1, control cycles are performed according to the torque increment T. d Increase torque and control motor operation.

2. The method for controlling slippage of an electric two-wheeled vehicle according to claim 1, characterized in that, The electric two-wheeled vehicle slippage control method also includes: According to the predetermined negative torque T r When the motor operates for a slippage suppression time t, or when the driving speed of the electric two-wheeler is detected to be lower than the speed threshold, the predetermined negative torque T is determined. r The motor is controlled to operate under predetermined conditions; otherwise, it is determined that the predetermined conditions have not yet been met.

3. The method for controlling slippage of an electric two-wheeled vehicle according to claim 2, characterized in that, The electric two-wheeled vehicle slippage control method also includes: The slippage suppression time t is determined based on the road surface slippage coefficient k. The larger the road surface slippage coefficient k, the smaller the slippage suppression time t.

4. The method for controlling slippage of an electric two-wheeled vehicle according to claim 1, characterized in that, The initial given torque T1 is greater than 0.

5. The method for controlling slippage of an electric two-wheeled vehicle according to claim 4, characterized in that, The electric two-wheeled vehicle slippage control method also includes: The initial torque T1 is determined based on the road surface slip coefficient k. The larger the road surface slip coefficient k, the smaller the initial torque T1.

6. The method for controlling slippage of an electric two-wheeled vehicle according to claim 1, characterized in that, The electric two-wheeled vehicle slippage control method also includes: During the operation of the electric two-wheeled vehicle, the speed of the drive wheels is collected by a speed sensor installed on the drive wheels, and the vehicle is used to detect whether the vehicle is slipping based on the speed of the drive wheels.

7. The method for controlling slippage of an electric two-wheeled vehicle according to claim 6, characterized in that, Detecting whether an electric two-wheeler is slipping based on the speed of the drive wheels includes: The drive wheel acceleration 'a' is determined based on the drive wheel speeds of the current and previous control cycles. When the drive wheel acceleration 'a' reaches the acceleration threshold 'a' during the operation of the electric two-wheeled vehicle... th At that time, it was determined that the electric two-wheeler was slipping.

8. The method for controlling slippage of an electric two-wheeled vehicle according to claim 1, characterized in that, The road surface slip coefficient k is determined based on the driving state parameters of the electric two-wheeled vehicle when slippage occurs, including: The slip coefficient lookup table is used to determine the drive wheel acceleration *a* and motor torque *T* when slippage occurs on an electric two-wheeled vehicle. e The corresponding road surface slip coefficient k; Among them, the slip coefficient lookup table is pre-established, and the motor torque T is obtained under the same drive wheel acceleration a. e The smaller the value, the larger the corresponding road surface slip coefficient k. For the same motor torque T, e The greater the acceleration 'a' of the lower drive wheel, the greater the corresponding road surface slip coefficient 'k'.

9. The method for controlling slippage of an electric two-wheeled vehicle according to claim 1, characterized in that, The electric two-wheeled vehicle slippage control method also includes: Starting from the initial given torque T1, control cycles are performed according to the torque increment T. d Increase the torque and control the motor to work until slippage of the electric two-wheeler is detected again, or until the maximum torque is reached and the motor is controlled to work at the maximum torque.

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