Driving anti-skid control method, motor controller and electric two-wheeled vehicle
By monitoring motor current and speed, and calculating drive wheel speed using Hall sensor signals, the problem of slippage on low-friction surfaces of electric two-wheeled vehicles has been solved. This achieves rapid and accurate slippage suppression without the need for additional sensors, improving the intelligence and safety of the motor controller.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YADEA TECH GRP CO LTD
- Filing Date
- 2023-11-13
- Publication Date
- 2026-06-12
Smart Images
Figure CN117325670B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electric vehicle control technology, and in particular to a drive anti-skid control method, a motor controller, and an electric two-wheeler. Background Technology
[0002] On certain road surfaces with low tire-to-ground friction coefficients, such as when electric two-wheelers are traveling on icy, muddy, or slippery roads, the motor's output torque can easily exceed the friction between the ground and the tires, causing the drive wheels to slip and potentially leading to rollovers or other dangerous situations. Typically, wheel speed or acceleration sensors need to be installed on the electric two-wheeler to determine if the vehicle is slipping and to take appropriate control measures. However, this increases the vehicle's manufacturing cost and requires regular maintenance, making it inconvenient for owners. Summary of the Invention
[0003] To address the aforementioned problems and technical needs, the inventors have proposed a drive anti-slip control method, a motor controller, and an electric two-wheeler. This method eliminates the need for additional sensors, relying on the motor's current and speed to monitor the vehicle's status. At the moment of slippage, it intervenes to control the motor's speed and output torque to suppress slippage, maintain vehicle stability, and assist the user in controlling the vehicle. The technical solution of this invention is as follows:
[0004] In a first aspect, this application provides a drive anti-slip control method, comprising the following steps:
[0005] The overall condition of the vehicle is determined based on the current and speed of the two-wheeled vehicle's motor.
[0006] When it is determined that the vehicle is slipping, adjust the speed of the drive wheels to ensure that it does not exceed the target speed;
[0007] The motor output torque is gradually increased from zero, and the speed of the drive wheels is monitored in real time.
[0008] The vehicle slip ratio is calculated based on the speed of the drive wheels during the torque change process. When the vehicle slip ratio is less than the expected slip ratio and the slip suppression exit condition is met, the vehicle status is re-evaluated based on the current and speed of the two-wheel motors. If the slip suppression exit condition is not met, the torque is continuously increased.
[0009] When the vehicle slip ratio is not less than the expected slip ratio, the vehicle is again judged to be slipping, and the drive wheel speed is readjusted to ensure that it does not exceed the target speed.
[0010] The slip suppression exit condition is that the motor output torque increases to the target torque or the drive wheel speed recovers to the speed before the most recent vehicle slippage, and the target torque is the motor output torque before the most recent vehicle slippage.
[0011] Its further technical solution involves determining the overall vehicle status based on the current and speed of the two-wheeled vehicle's motor, including:
[0012] Real-time monitoring of the current and speed of the two-wheeled vehicle's motor;
[0013] When the motor current is lower than the set minimum current value and the motor speed is higher than the set maximum speed value, the vehicle is judged to be slipping.
[0014] Otherwise, the current change rate and drive wheel acceleration are calculated. When the current change rate is less than zero and the drive wheel acceleration is greater than the set acceleration threshold, the vehicle is determined to be slipping.
[0015] A further technical solution involves calculating the vehicle slip ratio during torque changes based on the drive wheel speed, including:
[0016] During the torque change process, when the speed of the driving wheel V2 at a certain sampling moment is greater than the speed of the driving wheel V1 at the previous sampling moment, the vehicle slip ratio S' during the sampling period is calculated; otherwise, the torque is continuously increased.
[0017] The calculation expression is: S'=(V2-V1) / V1.
[0018] A further technical solution is that the method also includes:
[0019] The target speed Vm' is calculated based on the drive wheel speed Vc before the most recent vehicle slippage and the expected slip ratio So. The expression is: Vm'=(So+1)*Vc.
[0020] A further technical solution is that the method also includes:
[0021] For different vehicle power and weight, a self-learning method is used to select the corresponding minimum current, maximum speed, acceleration threshold and desired slip ratio.
[0022] A further technical solution is that the method also includes:
[0023] The speed of the drive wheel is calculated based on the signal changes of the Hall sensor built into the motor and the rolling radius of the drive wheel.
[0024] A further technical solution is that the method also includes:
[0025] When the slip suppression exit condition is met, the motor output torque is gradually restored to the input value of the throttle signal, and the overall vehicle status is monitored again.
[0026] Secondly, this application also provides a motor controller, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described in the first aspect.
[0027] The further technical solution is that the motor controller receives the threshold parameters required by the method input from the external terminal according to its own communication protocol, including the minimum current value, the maximum speed value, the acceleration threshold and the desired slip ratio;
[0028] The motor controller connects to a remote server to upload controller parameters and data generated during execution, and to receive controller optimization parameters and threshold optimization parameters from the server.
[0029] Thirdly, this application also provides an electric two-wheeled vehicle that uses the motor controller described in the second aspect to achieve anti-slip control during vehicle operation.
[0030] The beneficial technical effects of this invention are:
[0031] 1) There is no need to install an additional front wheel sensor on the electric two-wheeler. The system can determine whether the vehicle is slipping by collecting motor current and motor speed.
[0032] 2) There is no need to install additional wheel speed sensors on the electric two-wheeler. The motor speed is calculated by the signal of the Hall sensor inside the motor, and the wheel speed of the drive wheel is further converted by combining the rolling radius of the vehicle's drive wheel.
[0033] 3) When slippage occurs, reduce the speed of the drive wheels and control the motor output torque to gradually increase from zero. During the torque change process, monitor the degree of slippage and exit slippage control by comparing the overall vehicle slip ratio with the desired slip ratio.
[0034] 4) Compared to the traditional method of using the ABS (Anti-lock Braking System) controller to monitor wheel speed in real time and then sending corresponding control signals to the motor controller based on the monitoring results, this application integrates the computer program of the drive anti-slip control method into the motor controller. That is, the judgment of the vehicle slip state and the slip suppression processing are both realized through the motor controller, which can more quickly and accurately control the motor directly, achieve timely response and tracking of vehicle status, and ensure the user's riding safety.
[0035] 5) The threshold parameters required for control can be selected through self-learning, which improves the versatility of the motor controller. It can also be used with the help of the vehicle's intelligent architecture to quickly give threshold parameters through external terminals.
[0036] 6) The motor controller uploads its own parameters and the parameters generated during execution to a remote server, collects the number of trigger slips and information on different scenarios, performs big data analysis and processing, and supports the continuous optimization and upgrading of the motor controller. Attached Figure Description
[0037] Figure 1 This is a flowchart of the drive anti-slip control method provided in this application.
[0038] Figure 2 This is a flowchart of the vehicle status determination method provided in this application.
[0039] Figure 3 This is a schematic diagram of motor speed acquisition provided in this application.
[0040] Figure 4 This is a flowchart of the slip suppression processing method provided in this application.
[0041] Figure 5 This is a schematic diagram of the intelligent architecture of the whole vehicle provided in this application. Detailed Implementation
[0042] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.
[0043] Please refer to Figure 1 As shown, the driving anti-slip control method provided in this application specifically includes the following steps:
[0044] Step 1: Determine the overall condition of the vehicle based on the current and speed of the two-wheeled vehicle's motor. For example... Figure 2 As shown, it includes the following steps:
[0045] Step 1.1: When a throttle signal is input, the two-wheeled vehicle's motor starts operating. Optionally, this motor is a hub motor, used to provide power to the two-wheeled vehicle's drive wheels.
[0046] Step 1.2: Monitor the current and speed of the two-wheeled vehicle motor in real time.
[0047] The motor speed is calculated based on the signal changes from the Hall effect sensor built into the motor. For example... Figure 3 As shown, the inner ring is the motor stator, and the Hall sensor is fixed on the stator. The outer ring is the motor rotor, and multiple permanent magnets are bonded to the inner surface of the rotor. When the rotor rotates, the Hall sensor on the stator senses the change in the magnetic field and outputs a corresponding pulse signal. Based on the number of pulses m captured within a fixed sampling time t, the motor speed n = 1000*m / (p*t) is calculated, where n is in revolutions per second, t is in milliseconds, and p is the number of pole pairs of the motor magnets, i.e., how many pairs of magnetic poles are in one ring inside the motor.
[0048] Step 1.3: When the motor current is lower than the set minimum current value and the motor speed is greater than the set maximum speed value, it is determined that the vehicle is slipping (side slipping). At this time, the slip status flag is set to 1.
[0049] Step 1.4: When the motor current is not lower than the set minimum current value and the motor speed is not greater than the set maximum speed value, calculate the current change rate Ki and the drive wheel acceleration a2.
[0050] The speed V of the driving wheel is calculated based on the motor speed n and the rolling radius r of the driving wheel. The calculation expression is: V=2π*r*n=2π*r*1000*m / (p*t); r is in meters, and V is in meters / second; then the acceleration of the driving wheel a=dV / dt.
[0051] Step 1.5: When the rate of change of current is less than zero (Ki < 0) and the acceleration of the drive wheel is greater than the set acceleration threshold a1 (a2 > a1), it is determined that the vehicle is slipping. At this time, the slip status flag is set to 1; otherwise, the motor runs normally and steps 1.2 to 1.5 are repeated.
[0052] When a vehicle skids, it is necessary to actively and quickly control the motor speed and output torque, i.e., to initiate the slip suppression process to maintain vehicle stability. Combined with... Figure 1 , Figure 4 As shown, it includes the following steps:
[0053] Step 2: When it is determined that the vehicle is slipping, adjust the speed of the drive wheels so that it does not exceed the target speed.
[0054] Step 2.1: When the slip state flag is 1, the drive wheel speed Vc before the most recent vehicle slippage is defined as the vehicle speed, and the motor output torque before the most recent vehicle slippage is defined as the target torque Tc. The drive wheel speed Vm after slippage is sampled at certain time intervals, and then the vehicle slip ratio Sc = (Vm - Vc) / Vc is obtained.
[0055] Step 2.2: Calculate the target speed Vm' based on the drive wheel speed Vc before the most recent vehicle slippage and the expected slip ratio So. From So = (Vm' - Vc) / Vc, we get: Vm' = (So + 1) * Vc. Where So is the set upper limit of the slip ratio when the vehicle is not slipping (So ≤ Sc), abbreviated as expected slip ratio, and its specific value is obtained through comprehensive vehicle and road surface testing and calibration; the target speed Vm' can be understood as the maximum drive wheel speed that the vehicle can achieve under the upper limit of the slip ratio.
[0056] Step 2.3: Control the motor speed to decrease so that the drive wheel speed Vmt does not exceed the target speed Vm', so that the vehicle can quickly get out of the slipping state.
[0057] Step 3: Control the motor output torque to gradually increase from zero, and monitor the drive wheel speed in real time.
[0058] When the wheel speed decreases, in order to avoid slipping again immediately, consider first removing the drive wheel torque (i.e., adjusting it to zero), and then gradually increasing it to the target torque Tc. The torque can be increased by increasing the motor current.
[0059] Step 4: Calculate the vehicle slip ratio during the torque change process based on the drive wheel speed.
[0060] During the torque change process, when the driving wheel speed V2 at a certain sampling time t2 is greater than the driving wheel speed V1 at the previous sampling time t1, the vehicle slip ratio S' = (V2 - V1) / V1 during the sampling period is calculated; when V2 ≤ V1, the torque is continuously increased.
[0061] Step 5: When the vehicle slip ratio S' is less than the desired slip ratio So and the slip suppression exit condition is met, set the slip status flag to 0, gradually restore the motor output torque to the input value of the throttle signal, and re-execute Step 1, i.e., monitor the vehicle status in real time; if the slip suppression exit condition is not met, continuously increase the torque.
[0062] The slip suppression exit condition is that the motor output torque increases to the target torque or the drive wheel speed returns to the speed before the most recent vehicle slippage.
[0063] Step 6: When the vehicle slip ratio S' is not less than the expected slip ratio So, determine again that the vehicle is slipping, and repeat step 2 to update the target torque Tc and target speed Vm'.
[0064] In this embodiment, no additional sensors are required. The motor speed is obtained by the Hall sensor built into the two-wheeled vehicle motor, and the speed of the drive wheel is obtained by combining the rolling radius of the drive wheel. The overall vehicle status is determined by monitoring the motor speed and current. When the vehicle is driving normally, the calculated drive wheel speed can be taken as the overall vehicle speed. When the vehicle slips, the motor speed and output torque are controlled to suppress the slippage phenomenon, that is, the wheel speed is reduced to the target speed and the output torque is gradually increased from zero. During the slip suppression process, the updated overall vehicle slip ratio S' is used as the closed-loop input. The motor controller controls the closed-loop output torque of the motor to keep the slip ratio within a controllable range and make the motor output torque gradually track to the target torque value, thereby maintaining the vehicle stable driving on special road surfaces and assisting the user in controlling the vehicle.
[0065] The threshold parameters required by the above methods, such as minimum current, maximum speed, acceleration threshold, and desired slip ratio, will vary depending on the vehicle's power and weight. Therefore, calibration and adjustment are necessary for different vehicle models. One approach is to use a self-learning method to select the appropriate minimum current, maximum speed, acceleration threshold, and desired slip ratio. Specifically, an unloaded test is performed on each vehicle model, with the throttle turned to its maximum. The motor current and speed are collected during this process, generating their respective change curves to determine the minimum current and maximum speed for that model. A loaded road test is then performed on each model, collecting the motor speed during this process. The acceleration of the drive wheel corresponding to the speed at which slippage is about to occur is identified as the acceleration threshold for that model, and the overall vehicle slip ratio calculated at the point where slippage is about to occur is identified as the desired slip ratio for that model. After the test is completed, a threshold parameter table for all test models is generated and stored in the motor controller. When the motor controller is put into self-learning mode through certain operation methods, the corresponding threshold parameter is selected from the threshold parameter table according to the current model. Then, the self-learning mode is exited through certain operation methods, and the threshold parameter adjustment and calibration are completed. In this way, a motor controller can perform anti-skid control for multiple models, which not only reduces the vehicle recycling cost but also improves the overall vehicle intelligence.
[0066] Another method is to directly write the corresponding threshold parameters into the motor controller during production, based on the vehicle model being installed, through a programming process. While this is convenient and quick, the motor controller cannot be reused. Yet another method is to use an external terminal to adjust and calibrate the threshold parameters in the motor controller via communication.
[0067] Based on the same inventive concept, this application also provides a motor controller, including a connected processor, memory, and network interface. The processor provides computational and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The motor controller's database stores threshold parameters and calculated data. The motor controller's network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements the various steps of a drive anti-slip control method. The method steps are the same as steps 1 to 6 described above and will not be repeated here.
[0068] like Figure 5As shown, the motor controller receives threshold parameters required by the method input from an external terminal according to its built-in communication protocol. These parameters include the minimum current, maximum speed, acceleration threshold, and desired slip ratio. The external terminal can be a host computer, a mobile app, or other communication terminal. The motor controller connects to a remote server via communication modules such as 4G and GPRS to upload controller parameters and data generated during method execution (including the number of slip triggers). Developers can use the server to perform big data analysis on the uploaded data, combining it with information from different scenarios, to optimize controller parameters and threshold parameters. The motor controller receives optimized controller parameters and threshold optimization parameters from the server, enabling controller optimization and upgrades.
[0069] Based on the same inventive concept, this application also provides an electric two-wheeled vehicle that uses the motor controller described above to achieve anti-slip control during vehicle operation.
[0070] The above descriptions are merely preferred embodiments of this application, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.
Claims
1. A drive slip control method, characterized by, The method includes: The overall condition of the vehicle is determined based on the current and speed of the two-wheeled vehicle's motor. When it is determined that the vehicle is slipping, adjust the speed of the drive wheels to ensure that it does not exceed the target speed; The motor output torque is gradually increased from zero, and the speed of the drive wheels is monitored in real time. The vehicle slip ratio is calculated based on the speed of the drive wheels during the torque change process. When the vehicle slip ratio is less than the expected slip ratio and the slip suppression exit condition is met, the process of judging the vehicle state based on the current and speed of the two-wheeled vehicle motors is repeated. If the slip suppression exit condition is not met, the torque is continuously increased. When the vehicle slip ratio is not less than the expected slip ratio, it is determined again that the vehicle is slipping, and the adjustment of the drive wheel speed is repeated to ensure that it does not exceed the target speed. The step of determining the overall vehicle status based on the current and speed of the two-wheeled vehicle motor includes: Real-time monitoring of the current and speed of the two-wheeled vehicle's motor; When the motor current is lower than the set minimum current value and the motor speed is higher than the set maximum speed value, the vehicle is judged to be slipping. Otherwise, calculate the rate of change of current and the acceleration of the drive wheel. If the rate of change of current is less than zero and the acceleration of the drive wheel is greater than the set acceleration threshold, then it is determined that the vehicle is slipping. The slip suppression exit condition is that the motor output torque increases to the target torque or the drive wheel speed recovers to the speed before the most recent vehicle slippage, where the target torque is the motor output torque before the most recent vehicle slippage.
2. The drive slip control method according to claim 1, characterized in that The calculation of the vehicle slip ratio during the torque change process based on the drive wheel speed includes: During the torque change process, when the speed of the driving wheel V2 at a certain sampling moment is greater than the speed of the driving wheel V1 at the previous sampling moment, the vehicle slip ratio S' during the sampling period is calculated; otherwise, the torque is continuously increased. The calculation expression is: S'=(V2-V1) / V1.
3. The drive anti-slip control method according to claim 1, characterized in that, The method further includes: The target speed Vm' is calculated based on the drive wheel speed Vc before the most recent vehicle slippage and the expected slip ratio So. The expression is: Vm'=(So+1)*Vc.
4. The drive anti-slip control method according to claim 1, characterized in that, The method further includes: For different vehicle power and weight, a self-learning method is used to select the corresponding minimum current, maximum speed, acceleration threshold and desired slip ratio.
5. The drive anti-slip control method according to claim 1, characterized in that, The method further includes: The speed of the drive wheel is calculated based on the signal changes of the Hall sensor built into the motor and the rolling radius of the drive wheel.
6. The drive anti-slip control method according to claim 1, characterized in that, The method further includes: When the slip suppression exit condition is met, the motor output torque is gradually restored to the input value of the throttle signal, and the overall vehicle status is monitored again.
7. A motor controller, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.
8. The motor controller according to claim 7, characterized in that, The motor controller receives threshold parameters required by the method from an external terminal according to its built-in communication protocol, including minimum current, maximum speed, acceleration threshold, and desired slip ratio. The motor controller is connected to a remote server to upload controller parameters and data generated during execution, and to receive controller optimization parameters and threshold optimization parameters from the server.
9. An electric two-wheeled vehicle, characterized in that, The motor controller described in claim 7 or 8 is used to achieve drive anti-slip control during vehicle operation.