Drive Anti-slip control method, electric motor controller, and electric two-wheeled vehicle

Abstract

The present invention relates to the technical field of electric vehicle control. Disclosed are a drive anti-slip control control method, an electric motor controller, and an electric two-wheeled vehicle. The method comprises: determining the state of a vehicle on the basis of the current and rotation speed of an electric motor; when it is determined that the vehicle slips, adjusting the speed of a driving wheel, such that the speed of the driving wheel does not exceed a target speed; controlling an output torque of the electric motor to gradually increase from zero, and monitoring the speed of the driving wheel in real time; calculating a slip rate of the vehicle in a torque change process, and when a calculated value is less than an expected slip rate and a slip suppression exit condition is met, re-determining the state of the vehicle; when the slip suppression exit condition is not met, continuously increasing the torque; and when the calculated value is not less than the expected slip rate, re-determining that the vehicle slips, and readjusting the speed of the driving wheel, such that the speed of the driving wheel does not exceed the updated target speed. The present method does not require an additional sensor, reduces the rotation speed of an electric motor at the moment of slipping, and smoothly and accurately controls an output torque to suppress the phenomenon of slipping, thereby maintaining the stability of a vehicle.

Description

Drive anti-skid control method, motor controller and electric two-wheeled vehicle Technical Field

[0001] The present invention relates to the technical field of electric vehicle control, in particular to a drive anti-skid control method, a motor controller and an electric two-wheeled vehicle. Background Art

[0002] On some special road surfaces with a low coefficient of friction between the tire and the ground, such as when an electric two-wheeler is driving on ice, snow, mud, or slippery surfaces, the motor output torque can easily far exceed the friction between the ground and the tire, causing the drive wheels to slip and potentially leading to dangerous situations such as rollover. Electric two-wheelers typically require sensors such as wheel speed or acceleration to determine whether the vehicle is slipping and to implement appropriate control measures. However, this increases vehicle manufacturing costs and requires regular maintenance, making it inconvenient for owners.

[0003] Summary of the Invention

[0004] In response to the above-mentioned problems and technical needs, the inventors have proposed a drive anti-skid control method, a motor controller, and an electric two-wheeled vehicle. These methods, without requiring additional sensors, rely on the current and speed of the two-wheeled vehicle's motor to monitor the vehicle's status. At the moment of slippage, the motor speed and output torque are controlled to suppress slippage, maintain vehicle stability, and assist the user in controlling the vehicle. The technical solutions of the present invention are as follows:

[0005] In a first aspect, the present application provides a drive anti-skid control method, comprising the following steps:

[0006] Determine the status of the vehicle based on the current and speed of the two-wheeled vehicle motor;

[0007] When it is determined that the vehicle is slipping, the driving wheel speed is adjusted so that it does not exceed the target speed;

[0008] Control the motor output torque to gradually increase from zero and monitor the drive wheel speed in real time;

[0009] The vehicle slip ratio during the torque change process is calculated based on the driving wheel speed. 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-determined based on the current and speed of the two-wheeled vehicle motor. If the slip suppression exit condition is not met, the torque is continuously increased.

[0010] When the vehicle slip rate is not less than the expected slip rate, the vehicle is again determined to be slipping, and the drive wheel speed is adjusted again so that it does not exceed the target speed;

[0011] Among them, the slip suppression exit condition is that the motor output torque increases to the target torque size or the drive wheel speed returns to the speed before the vehicle slipped last time, and the target torque is the motor output torque before the vehicle slipped last time.

[0012] A further technical solution is to determine the status of the entire vehicle based on the current and speed of the two-wheeled vehicle motor, including:

[0013] Real-time monitoring of the current and speed of two-wheeled vehicle motors;

[0014] 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;

[0015] Otherwise, the current change rate and the driving wheel acceleration are calculated. When the current change rate is less than zero and the driving wheel acceleration is greater than the set acceleration threshold, it is determined that the vehicle is slipping.

[0016] A further technical solution is to calculate the vehicle slip rate during the torque change process based on the driving wheel speed, including:

[0017] During the torque change process, when the driving wheel speed V2 at a certain sampling moment is greater than the driving wheel speed V1 at the previous sampling moment, the vehicle slip rate S' of the sampling period is calculated, otherwise the torque is continuously increased;

[0018] The calculation expression is: S'=(V2-V1) / V1.

[0019] Its further technical solution is that the method further comprises:

[0020] The target speed Vm' is calculated based on the driving wheel speed Vc before the vehicle slipped the most recently and the expected slip ratio So, and the expression is: Vm'=(So+1)*Vc.

[0021] Its further technical solution is that the method further comprises:

[0022] For different vehicle powers and weights, the corresponding minimum current, maximum speed, acceleration threshold and expected slip rate are selected by self-learning.

[0023] Its further technical solution is that the method further comprises:

[0024] The driving wheel speed is calculated based on the signal change of the Hall sensor built into the motor and the rolling radius of the driving wheel.

[0025] Its further technical solution is that the method further comprises:

[0026] When the slip suppression exit conditions are met, the motor output torque is gradually restored to the input value of the throttle signal, and the vehicle status is re-monitored.

[0027] In a second aspect, the present application further provides a motor controller comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method described in the first aspect when executing the computer program.

[0028] A 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 value and the expected slip rate;

[0029] The motor controller is connected to a remote server to upload controller parameters and data generated when executing the method, and to receive controller optimization parameters and threshold optimization parameters sent by the server.

[0030] In a third aspect, the present application also provides an electric two-wheeled vehicle, which adopts the motor controller described in the second aspect to achieve drive anti-skid control during vehicle driving.

[0031] The beneficial technical effects of the present invention are:

[0032] 1) No additional front wheel sensor is required on the electric two-wheeled vehicle. The vehicle can be judged whether it has entered a slipping state by collecting motor current and motor speed.

[0033] 2) No additional wheel speed sensor is required on the electric two-wheeled vehicle. The motor speed is calculated using the Hall sensor signal inside the motor, and the driving wheel speed is further converted into the rolling radius of the vehicle's driving wheel.

[0034] 3) When slip occurs, the drive wheel speed is reduced and the motor output torque is gradually increased from zero. During the torque change, the vehicle slip rate is compared with the expected slip rate to monitor the slip degree and exit slip control;

[0035] 4) Compared to the traditional method of using an ABS (Anti-lock Braking System) controller to monitor wheel speed in real time and then send corresponding control signals to the motor controller based on the monitoring results, the present application integrates the computer program driving the anti-skid control method into the motor controller. That is, the entire vehicle slip state judgment and slip suppression processing are both implemented by the motor controller. This can directly control the motor more quickly and accurately, achieve timely response and tracking of vehicle status, and ensure user riding safety;

[0036] 5) The threshold parameters required for control can be selected through self-learning, which improves the versatility of the motor controller. Threshold parameters can also be quickly set through external terminals using the vehicle's intelligent architecture.

[0037] 6) The motor controller uploads its own parameters and the parameters generated during the execution method to the remote server, collects the number of triggered slips and different scenario information, performs big data analysis and processing, and supports continuous optimization and upgrading of the motor controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG1 is a flow chart of the drive anti-skid control method provided in this application.

[0039] FIG2 is a flow chart of the vehicle status determination method provided in this application.

[0040] FIG3 is a schematic diagram of motor speed acquisition provided by this application.

[0041] FIG4 is a flow chart of the slip suppression processing method provided in this application.

[0042] Figure 5 is a schematic diagram of the vehicle intelligent architecture provided by this application. DETAILED DESCRIPTION

[0043] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0044] Referring to FIG1 , the present application provides a driving anti-skid control method, which specifically includes the following steps:

[0045] Step 1: Determine the vehicle status based on the current and speed of the two-wheeled vehicle motor. As shown in Figure 2, this includes the following steps:

[0046] Step 1.1: When a throttle signal is input, the motor of the two-wheeled vehicle starts running. Optionally, the motor is a hub motor used to provide power to the drive wheels of the two-wheeled vehicle.

[0047] Step 1.2: Monitor the current and speed of the two-wheeler motor in real time.

[0048] The motor speed is calculated based on the signal changes from the built-in Hall effect sensors. As shown in Figure 3, the inner ring is the motor stator, to which the Hall effect sensors are fixed. The outer ring is the motor rotor, with multiple permanent magnets bonded to its inner surface. As the rotor rotates, the Hall effect sensors on the stator sense the changes in the magnetic field and output corresponding pulse signals. Based on the number of pulses m captured within a fixed sampling time t, the motor speed is calculated as n = 1000 * m / (p * t), where n is in revolutions per second and t is in milliseconds. p is the number of magnetic pole pairs in the motor, that is, the number of magnetic pole pairs within one rotation of the motor.

[0049] 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 sliding), and the slip status flag is set to 1.

[0050] Step 1.4: When the motor current is not less than the set minimum current value and the motor speed is not greater than the set maximum speed, calculate the current change rate Ki and the driving wheel acceleration a2.

[0051] The driving wheel speed V 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 driving wheel acceleration a = dV / dt.

[0052] Step 1.5: When the current change rate is less than zero (Ki < 0) and the drive wheel acceleration is greater than the set acceleration threshold a1 (a2 > a1), the vehicle is determined to be slipping, and the slip status flag is set to 1; otherwise, the motor operates normally and steps 1.2 to 1.5 are repeated.

[0053] When the vehicle skids, it is necessary to actively and quickly control the motor speed and output torque accordingly, that is, to enter the slip suppression process to maintain vehicle stability. As shown in Figures 1 and 4, the following steps are included:

[0054] Step 2: When it is determined that the vehicle is slipping, adjust the driving wheel speed so that it does not exceed the target speed.

[0055] Step 2.1: When the slip status flag is 1, obtain the drive wheel speed Vc before the most recent vehicle slip and define it as the vehicle speed. Also obtain the motor output torque before the most recent vehicle slip and define it as the target torque Tc. Sample the drive wheel speed Vm after the slip at regular intervals. The vehicle slip ratio Sc at this point is calculated as (Vm - Vc) / Vc.

[0056] Step 2.2: Calculate the target speed Vm' based on the drive wheel speed Vc before the most recent vehicle slip and the desired slip ratio So. So = (Vm' - Vc) / Vc, resulting in: Vm' = (So + 1) * Vc. So is the upper limit of the vehicle's slip ratio (So ≤ Sc) when the vehicle is not slipping, also referred to as the desired slip ratio. The specific value is determined through comprehensive vehicle and road surface testing and calibration. The target speed Vm' can be understood as the maximum drive wheel speed the vehicle can achieve within the upper limit of the slip ratio.

[0057] 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 escape from the skidding state.

[0058] Step 3: Control the motor output torque to gradually increase from zero, and monitor the drive wheel speed in real time.

[0059] When the wheel speed decreases, in order to avoid immediately entering the slip state again, 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.

[0060] Step 4: Calculate the vehicle slip rate during torque changes based on the drive wheel speed.

[0061] 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 rate S'=(V2-V1) / V1 during the sampling period is calculated; when V2≤V1, the torque continues to increase.

[0062] Step 5: When the vehicle slip rate S' is less than the expected slip rate So and the slip suppression exit condition is met, the slip status flag is set to 0, and the motor output torque is gradually restored to the input value of the throttle signal. Then, step 1 is executed again, that is, the vehicle status is monitored in real time. When the slip suppression exit condition is not met, the torque is continuously increased.

[0063] Among them, the slip suppression exit condition is that the motor output torque increases to the target torque size or the drive wheel speed returns to the speed before the vehicle slipped last time.

[0064] Step 6: When the vehicle slip ratio S' is not less than the expected slip ratio So, it is determined again that the vehicle is slipping, and step 2 is re-executed to update the target torque Tc and target speed Vm'.

[0065] In this embodiment, no additional sensors are required. The motor speed is obtained by relying on the Hall sensor built into the motor of the two-wheeled vehicle, and the driving wheel speed is obtained by combining it with the rolling radius of the driving wheel. The state of the entire vehicle is determined by monitoring the motor speed and current. When the vehicle is driving normally, the calculated driving wheel speed can be identified as the speed of the entire vehicle. At the moment the vehicle slips, the motor speed and output torque are controlled to suppress the slip phenomenon, that is, the wheel speed is reduced to the target speed and the output torque is gradually increased from zero. In the slip suppression process, the feedback-updated vehicle slip rate S' is used as the closed-loop input, and the motor output torque closed-loop output is controlled by the motor controller to keep the slip rate always within a controllable range and gradually track the motor output torque to the target torque size, thereby maintaining the vehicle's stable driving even on special road surfaces and assisting the user in controlling the vehicle.

[0066] The threshold parameters required by the above method, such as minimum current, maximum speed, acceleration threshold, and expected slip ratio, vary depending on vehicle power and weight, requiring calibration and adjustment for each vehicle model. One method involves using self-learning to select the corresponding minimum current, maximum speed, acceleration threshold, and expected slip ratio. Specifically, each vehicle model is tested with no load, the throttle turned to its maximum, and the motor current and speed are measured. Separate curves are generated to determine the minimum current and maximum speed for that vehicle model. Each vehicle model is also tested on a loaded road surface, with the motor speed measured. The drive wheel acceleration corresponding to the impending slip is determined as the acceleration threshold for that vehicle model, and the vehicle slip ratio calculated at the impending slip is used as the expected slip ratio for that vehicle 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 enters the self-learning mode through a certain operation method, the corresponding threshold parameters are selected from the threshold parameter table according to the current model, and then the self-learning mode is exited in a certain operation method to complete the adjustment and calibration of the threshold parameters. In this way, a motor controller can perform drive anti-skid control for a variety of models, which not only reduces the vehicle recovery cost but also improves the intelligence of the entire vehicle.

[0067] Another method involves directly programming the corresponding threshold parameters for the vehicle model during motor controller production through a programming process. While this method is convenient and quick, it prevents the motor controller from being reused. Another method involves using an external terminal to adjust and calibrate the threshold parameters in the motor controller via communication.

[0068] Based on the same inventive concept, the present application also provides a motor controller, including a connected processor, memory and network interface. The processor is used to provide computing and control capabilities. The memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the motor controller is used to store threshold parameters and data generated by calculation. The network interface of the motor controller is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements the various steps of a drive anti-skid control method. The method steps refer to the contents of steps 1 to 6 above and will not be repeated here.

[0069] As shown in Figure 5, the motor controller uses its own communication protocol to receive the threshold parameters required for the method, including minimum current, maximum speed, acceleration threshold, and desired slip rate, from an external terminal. The external terminal can be a host computer, mobile app, or other communication terminal. The motor controller connects to a remote server via a communication module such as 4G or GPRS to upload controller parameters and data generated during method execution (including the number of triggered slips). Developers can use the server to perform big data analysis on the uploaded data, combined with information from different scenarios, to optimize controller parameters and threshold parameters. The motor controller then receives the optimized controller and threshold parameters from the server, enabling controller optimization and upgrades.

[0070] Based on the same inventive concept, the present application also provides an electric two-wheeled vehicle, which adopts the motor controller introduced above to achieve drive anti-skid control during vehicle driving.

[0071] The above description is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiment. It is understood that other improvements and variations directly derived or imagined by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the scope of protection of the present invention.

Claims

1. A driving anti-skid control method, characterized in that: The method comprises: Determine the vehicle status based on the current and speed of the two-wheeled vehicle motor; When it is determined that the vehicle is slipping, the driving wheel speed is adjusted so that it does not exceed the target speed; Control the motor output torque to gradually increase from zero, and monitor the drive wheel speed in real time; Calculating the vehicle slip rate during the torque change process according to the driving wheel speed, and when the vehicle slip rate is less than the expected slip rate and meets the slip suppression exit condition, re-execute the determination of the vehicle state according to the current and speed of the two-wheeled vehicle motor; when the slip suppression exit condition is not met, continuously increase the torque; When the vehicle slip rate is not less than the expected slip rate, determining that the vehicle is slipping again, and re-executing the step of adjusting the driving wheel speed so that it does not exceed the target speed; Among them, the slip suppression exit condition is that the motor output torque increases to the target torque size or the driving wheel speed returns to the speed before the vehicle slipped most recently, and the target torque is the motor output torque before the vehicle slipped most recently.

2. The driving anti-skid control method according to claim 1, characterized in that: The determining of the vehicle state according to the current and speed of the motor of the two-wheeled vehicle comprises: Real-time monitoring of the current and speed of two-wheeler motors; 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; Otherwise, the current change rate and the driving wheel acceleration are calculated, and when the current change rate is less than zero and the driving wheel acceleration is greater than a set acceleration threshold, it is determined that the vehicle is slipping.

3. The driving anti-skid control method according to claim 1, characterized in that: Calculating the vehicle slip rate during the torque change process according to the driving wheel speed includes: During the torque change process, when the driving wheel speed V2 at a certain sampling moment is greater than the driving wheel speed V1 at the previous sampling moment, the vehicle slip rate S' during the sampling period is calculated, otherwise the torque is continuously increased; The calculation expression is: S'=(V2-V1) / V1.

4. The driving anti-skid control method according to claim 1, characterized in that: The method further comprises: The target speed is calculated based on the driving wheel speed Vc and the expected slip ratio So before the vehicle slipped most recently. Vm', the expression is: Vm'=(So+1)*Vc.

5. The driving anti-skid control method according to claim 2, characterized in that: The method further comprises: For different vehicle powers and weights, the corresponding minimum current, maximum speed, acceleration threshold and expected slip rate are selected by self-learning.

6. The driving anti-skid control method according to claim 1, characterized in that: The method further comprises: The driving wheel speed is calculated based on the signal change of the Hall sensor built into the motor and the rolling radius of the driving wheel.

7. The driving anti-skid control method according to claim 1, characterized in that: The method further comprises: 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 vehicle status is monitored again.

8. 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, the steps of the method according to any one of claims 1 to 7 are implemented.

9. The motor controller according to claim 8, characterized in that: The motor controller receives the threshold parameters required by the method input from an external terminal according to its own communication protocol, including a minimum current value, a maximum speed value, an acceleration threshold value, and an expected slip rate; The motor controller is connected to a remote server to upload controller parameters and data generated when the method is executed, and to receive controller optimization parameters and threshold optimization parameters sent by the server.

10. An electric two-wheeled vehicle, characterized in that: The motor controller described in claim 8 or 9 is used to implement drive anti-skid control during vehicle driving.

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