Skid control method for electric two-wheeled vehicle considering slippery degree of road surface

Abstract

The invention discloses an electric two-wheeled vehicle slip control method considering the slippery degree of a road surface, and relates to the technical field of vehicles, and the method comprises the following steps: when detecting that an electric two-wheeled vehicle slips, firstly, controlling a motor to work according to a preset negative torque in a first stage, and rapidly inhibiting slip; determining a road surface slip coefficient according to a driving state parameter of the electric two-wheeled vehicle when the electric two-wheeled vehicle slips, then controlling the motor to work according to a preset negative torque to reach a preset condition, increasing the torque according to the torque increment and controlling the motor to work from the initial given torque one by one in a control period in a second stage, and controlling the motor to work when the road surface slip coefficient is larger. The higher the represented road surface wet and slippery degree is, the smaller the determined torque increment is, so that the effects of slowly increasing the torque on the wet and slippery road surface to avoid slipping again and rapidly increasing the torque on the relatively non-wet and slippery road surface to avoid pause are achieved, the driving stability of the electric two-wheeled vehicle can be guaranteed, and the riding experience can be optimized.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a method for controlling the slippage of an electric two-wheeled vehicle taking into account the degree of slipperiness of a road surface. Background Art

[0002] Electric two-wheelers are prone to slipping when starting, accelerating, and on slippery roads. In order to reduce the unsafe problems caused by slipping of electric two-wheelers, electric two-wheelers are generally controlled by traction control systems (TCS). The core idea is to consider slipping when the speed difference between the driving wheel and the driven wheel of the electric two-wheeler is greater than the set value. At this time, torque will be calculated and distributed to the driving wheel based on the speed difference, and slipping will be suppressed by reducing torque. However, the road conditions of electric two-wheelers are changeable, and a simple and single method of reducing torque can easily cause frustration, affecting the driving stability of the electric two-wheeler and the riding experience. Summary of the invention

[0003] In view of the above problems and technical requirements, this application proposes a skidding control method for an electric two-wheeled vehicle taking into account the slippery degree of the road surface. The technical solution of this application is as follows:

[0004] A method for controlling the slippage of an electric two-wheeled vehicle taking into account the slipperiness of a road surface, the method comprising:

[0005] When the electric two-wheeled vehicle is detected to be slipping, the road slip coefficient k is determined according to the driving state parameters of the electric two-wheeled vehicle when the slipping occurs, and the road slip coefficient k is set according to the predetermined negative torque T r Control the motor to work; wherein, the larger the road slip coefficient k is, the higher the slipperiness of the road surface represented;

[0006] Determine the torque increment T according to the road slip coefficient k d , the larger the road slip coefficient k, the greater the torque increment T d The smaller;

[0007] According to the predetermined negative torque T r After the motor reaches the predetermined working condition, the torque increment T is set in each control cycle starting from the initial given torque T1. d Increases torque and controls motor operation.

[0008] A further technical solution is that the electric two-wheeled vehicle skidding control method further includes:

[0009] According to the predetermined negative torque T r When the motor is controlled to work for the slip suppression time t, or when it is detected that the driving force speed of the electric two-wheeled vehicle is lower than the speed threshold, it is determined to be in accordance with the predetermined negative torque Tr The motor is controlled to work to meet the predetermined conditions, otherwise it is determined that the predetermined conditions have not been met.

[0010] A further technical solution is that the electric two-wheeled vehicle skidding control method further includes:

[0011] The slip suppression time t is determined according to the road slip coefficient k. The larger the road slip coefficient k is, the smaller the slip suppression time t is.

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

[0013] A further technical solution is that the electric two-wheeled vehicle skidding control method further includes:

[0014] The initial given torque T1 is determined according to the road slip coefficient k. The larger the road slip coefficient k is, the smaller the initial given torque T1 is.

[0015] A further technical solution is that the electric two-wheeled vehicle skidding control method further includes:

[0016] During the driving of the electric two-wheeled vehicle, the speed sensor disposed on the driving wheel of the electric two-wheeled vehicle collects the speed of the driving wheel, and detects whether the electric two-wheeled vehicle is slipping according to the speed of the driving wheel.

[0017] A further technical solution is to detect whether the electric two-wheeled vehicle is slipping according to the driving wheel speed, including:

[0018] The driving wheel acceleration a is determined according to the driving wheel speed in the current control cycle and the previous control cycle. When the driving wheel acceleration a is detected to reach the acceleration threshold a during the driving process of the electric two-wheeled vehicle, th When the electric two-wheeled vehicle is detected, it is determined that the electric two-wheeled vehicle is slipping.

[0019] A further technical solution is to determine the road slip coefficient k according to the driving state parameters of the electric two-wheeled vehicle when slipping occurs, including:

[0020] Query the slip coefficient lookup table to determine the driving wheel acceleration a and motor torque T when the electric two-wheeled vehicle slips e The corresponding road slip coefficient k;

[0021] Among them, the slip coefficient lookup table is pre-established, and the motor torque T under the same driving wheel acceleration a is e The smaller the value, the larger the corresponding road slip coefficient k. For the same motor torque T e The greater the lower driving wheel acceleration a is, the greater the corresponding road slip coefficient k is.

[0022] A further technical solution is that the electric two-wheeled vehicle skidding control method further includes:

[0023] Starting from the initial given torque T1, the torque increment T is set in each control cycle. d The torque is increased and the motor is controlled to work until the electric two-wheeled vehicle is detected to slip again, or until the torque is increased to the maximum torque and the motor is controlled to work according to the maximum torque.

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

[0025] The present application discloses a method for controlling the slippage of an electric two-wheeled vehicle taking into account the slippage of a road surface. When the slippage of the electric two-wheeled vehicle is detected, the method is controlled in two stages. In the first stage, a given negative torque is used to quickly suppress the slippage, and a road slip coefficient is determined according to the driving state parameters of the electric two-wheeled vehicle when the slippage occurs. Then, a torque increment matching the road slip coefficient can be determined according to the road slip coefficient. In the second stage, the torque can be increased according to the torque increment matching the road slippage, thereby achieving the effect of slowly increasing the torque on a slippery road surface to avoid slipping again, and quickly increasing the torque on a relatively non-slip road surface to avoid stalling. This can ensure the driving stability of the electric two-wheeled vehicle and optimize the riding experience.

[0026] The initial given torque of the second stage of the method is not fixed and starts 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 slip degree. The initial given torque of the second stage is also determined according to the road slip coefficient to match the road slip degree, so that the entire slip control process is carried out according to the road slip degree, which can better adapt to the slip control needs of different road slip degrees and ensure the driving stability and driving experience of the electric two-wheeled vehicle.

[0027] The method uses the acceleration of the driving wheel to detect whether the electric two-wheeled vehicle is slipping. There is no need to install a speed sensor on the driven wheel, which can reduce the use of devices, help reduce the amount of calculation and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of a method for controlling slippage of an electric two-wheeled vehicle according to an embodiment of the present application.

[0029] Figure 2 is a torque-time graph for an example. DETAILED DESCRIPTION

[0030] The specific implementation of the present application is further described below in conjunction with the accompanying drawings.

[0031] This application discloses a method for controlling the slippage of an electric two-wheeled vehicle taking into account the slipperiness of the road surface. Figure 1 As shown in the flowchart, the electric two-wheeled vehicle skidding control method comprises the following steps:

[0032] Step 1: Detect whether the electric two-wheeled vehicle slips during its travel.

[0033] The traditional method is to detect whether the electric two-wheeled vehicle is slipping by detecting the wheel speed difference between the driving wheel and the driven wheel of the electric two-wheeled vehicle. This method requires the arrangement of speed sensors on both the driving wheel and the driven wheel, requires the use of multiple speed sensors, and results in a high amount of calculation. In order to avoid this problem, in one embodiment, during the driving process of the electric two-wheeled vehicle, the speed of the driving wheel is collected by a speed sensor arranged on the driving wheel of the electric two-wheeled vehicle, and the slip of the electric two-wheeled vehicle is detected based on the speed of the driving wheel. That is, in this embodiment, it is only necessary to arrange a speed sensor on the driving wheel, and it is not necessary to arrange a speed sensor on the driven wheel. Detecting whether the electric two-wheeled vehicle is slipping based on the speed of the driving wheel includes:

[0034] The fundamental reason for the slippage of electric two-wheeled vehicles is that the friction between the tires and the ground is small on slippery roads, but the driving force of the motor is relatively large compared to the friction. Therefore, according to Newton's second law of motion, when slippage occurs, the acceleration of the wheel will rise sharply in a short time. Therefore, after the driving wheel speed is detected in each cycle, the driving wheel acceleration a is determined based on the driving wheel speed of the current control cycle and the previous control cycle. When the driving wheel acceleration a reaches the acceleration threshold a during the driving process of the electric two-wheeled vehicle, the acceleration of the driving wheel is determined based on the current control cycle and the previous control cycle. th When the electric two-wheeled vehicle is determined to be slipping. th Can be pre-calibrated.

[0035] When no slipping is detected, the current driving state is maintained and the vehicle continues to drive. When slipping is detected, the following step 2 is executed.

[0036] Step 2: when the electric two-wheeled vehicle is detected to be slipping, the road slip coefficient k is determined according to the driving state parameters of the electric two-wheeled vehicle when the slipping occurs, and the road slip coefficient k is adjusted according to the predetermined negative torque T r Control the motor to work, wherein the predetermined negative torque T r The torque is negative, and the specific torque value can be pre-calibrated and determined. When slippage is detected, the predetermined negative torque T is first switched to. r It can quickly suppress wheel slip and avoid the situation where there is still positive torque during slipping, causing the vehicle to continue slipping for a period of time.

[0037] The driving state parameters of the electric two-wheeled vehicle when slipping include the driving wheel acceleration a and the motor torque T when the electric two-wheeled vehicle slips. e, determining the road slip coefficient k according to the driving state parameters includes: querying the slip coefficient lookup table to determine the driving wheel acceleration a and the motor torque T when the electric two-wheeled vehicle slips e The corresponding road slip coefficient k. The larger the road slip coefficient k is, the higher the slipperiness of the road surface represented.

[0038] The wheel radius and vehicle mass of the electric two-wheeled vehicle are known, so the slip coefficient lookup table can be established in advance. In the established slip coefficient lookup table, the motor torque T under the same driving wheel acceleration a is e The smaller the road surface is, the lower the road surface adhesion coefficient is, the more slippery it is, and the corresponding road surface slip coefficient k is larger. e The greater the lower driving wheel acceleration a is, the lower the road adhesion coefficient is and the more slippery it is, and the corresponding road slip coefficient k is greater.

[0039] Step 3: Determine the torque increment T according to the road slip coefficient k d The larger the road slip coefficient k is, the larger the torque increment T will be. d The smaller the road slip coefficient k and the torque increment T d The corresponding relationship can be pre-built and set.

[0040] Step 4: According to the predetermined negative torque T r After the motor reaches the predetermined working condition, the torque increment T is set in each control cycle starting from the initial given torque T1. d Increases torque and controls motor operation.

[0041] In one embodiment, according to the predetermined negative torque T r When the motor is controlled to work for the slip suppression time t, or when it is detected that the driving force speed of the electric two-wheeled vehicle is lower than the speed threshold, it is determined to be in accordance with the predetermined negative torque T r The motor is controlled to work to meet the predetermined condition, otherwise it is determined that the predetermined condition has not been met. The skid suppression time t can be a fixed empirical value, or in order to achieve a better skid suppression effect, the skid suppression time t is determined according to the road surface slip coefficient k. The larger the road surface slip coefficient k, that is, the more slippery the road surface, the smaller the skid suppression time t.

[0042] In the second torque processing stage, the initial given torque T1 is not fixed to 0 torque, but a value greater than 0, so as to avoid the vehicle response delay caused by the torque being added again from 0, thereby improving the response speed. Furthermore, the initial given torque T1 is not a fixed value, but is matched with the slipperiness of the road surface. In one embodiment, the initial given torque T1 is determined according to the road slip coefficient k. The larger the road slip coefficient k, the smaller the initial given torque T1.

[0043] That is, the present invention is divided into two stages of skidding control after detecting the skidding of the electric two-wheeled vehicle. The first stage is based on the predetermined negative torque T r The second stage is the torque processing stage, which is based on the torque increment T corresponding to the slippery degree of the road surface. d Increasing the torque, the torque-time curve in an example is as follows Figure 2 As shown, in Figure 2 In the period from 0 to t1, the electric two-wheeled vehicle runs normally, and the motor torque continues to rise. At t1, the motor torque is T e When the electric two-wheeled vehicle is detected to be slipping, the predetermined negative torque T is switched to a negative value. r At time t2, the predetermined negative torque T r The motor is controlled to work until the slip suppression time t is reached. Then, starting from the initial given torque T1 corresponding to the road slip coefficient k, the torque increment T corresponding to the road slip coefficient k is set. d Increase the torque. In the torque processing stage, the larger the road slip coefficient k, that is, the higher the road slip degree, the initial given torque T1 and the torque increment T d If both are small, the torque will be increased slowly from the smaller initial given torque T1 to prevent the electric two-wheeled vehicle from slipping sharply again on the slippery road. When the road slip coefficient k is smaller, it means that the road is relatively non-slippery. d The torque is increased rapidly to avoid the slow increase of torque and the obvious setback of the electric two-wheeled vehicle. This allows for smooth operation and optimal body feel on different road surfaces.

[0044] Starting from the initial given torque T1, the torque increment T is set in each control cycle. d The torque is increased and the motor is controlled to work until the electric two-wheeled vehicle is detected to slip again and steps 2-4 are executed again, or until the torque is increased to the maximum torque and the motor is controlled to work according to the maximum torque.

[0045] The above is only a preferred embodiment of the present application, and the present application is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the protection scope of the present application.

Claims

1. A method for controlling the slippage of an electric two-wheeled vehicle taking into account the slipperiness of the road surface, characterized in that: The electric two-wheeled vehicle skidding control method comprises: When the electric two-wheeled vehicle is detected to be slipping, the road slip coefficient k is determined according to the driving state parameters of the electric two-wheeled vehicle when the slipping occurs, and the road slip coefficient k is set according to the predetermined negative torque T r Control the motor to work; wherein, the larger the road slip coefficient k is, the higher the slipperiness of the road surface represented; Determine the torque increment T according to the road slip coefficient k d , the larger the road slip coefficient k, the greater the torque increment T d The smaller; According to the predetermined negative torque T r After the motor reaches the predetermined working condition, the torque increment T is set in each control cycle starting from the initial given torque T1. d Increases torque and controls motor operation.

2. The electric two-wheeled vehicle skidding control method according to claim 1, characterized in that: The electric two-wheeled vehicle skidding control method further comprises: According to the predetermined negative torque T r When the motor is controlled to work for the slip suppression time t, or when it is detected that the driving force speed of the electric two-wheeled vehicle is lower than the speed threshold, it is determined to be in accordance with the predetermined negative torque T r The motor is controlled to work to meet a predetermined condition, otherwise it is determined that the predetermined condition has not been met.

3. The electric two-wheeled vehicle skidding control method according to claim 2, characterized in that: The electric two-wheeled vehicle skidding control method further comprises: The slip suppression time t is determined according to the road slip coefficient k. The larger the road slip coefficient k is, the smaller the slip suppression time t is.

4. The electric two-wheeled vehicle skidding control method according to claim 1, characterized in that: The initial given torque T1 is greater than 0.

5. The electric two-wheeled vehicle skidding control method according to claim 4, characterized in that: The electric two-wheeled vehicle skidding control method further comprises: The initial given torque T1 is determined according to the road slip coefficient k. The larger the road slip coefficient k is, the smaller the initial given torque T1 is.

6. The electric two-wheeled vehicle skidding control method according to claim 1, characterized in that: The electric two-wheeled vehicle skidding control method further comprises: During the driving of the electric two-wheeled vehicle, the speed sensor disposed on the driving wheel of the electric two-wheeled vehicle collects the speed of the driving wheel, and detects whether the electric two-wheeled vehicle is slipping according to the speed of the driving wheel.

7. The electric two-wheeled vehicle skidding control method according to claim 6, characterized in that: Detecting whether the electric two-wheeled vehicle is slipping based on the driving wheel speed includes: The driving wheel acceleration a is determined according to the driving wheel speed in the current control cycle and the previous control cycle. When the driving wheel acceleration a is detected to reach the acceleration threshold a during the driving process of the electric two-wheeled vehicle, th When the electric two-wheeled vehicle is detected, it is determined that the electric two-wheeled vehicle is slipping.

8. The electric two-wheeled vehicle skidding control method according to claim 1, characterized in that: The road slip coefficient k is determined based on the driving state parameters of the electric two-wheeled vehicle when slipping, including: Query the slip coefficient lookup table to determine the driving wheel acceleration a and motor torque T when the electric two-wheeled vehicle slips e The corresponding road slip coefficient k; Among them, the slip coefficient lookup table is pre-established, and the motor torque T under the same driving wheel acceleration a is e The smaller the value, the larger the corresponding road slip coefficient k. For the same motor torque T e The greater the lower driving wheel acceleration a is, the greater the corresponding road slip coefficient k is.

9. The electric two-wheeled vehicle skidding control method according to claim 1, characterized in that: The electric two-wheeled vehicle skidding control method further comprises: Starting from the initial given torque T1, the torque increment T is set in each control cycle. d The torque is increased and the motor is controlled to work until the electric two-wheeled vehicle is detected to slip again, or until the torque is increased to the maximum torque and the motor is controlled to work according to the maximum torque.

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