Driving anti-skid control method for two-wheeled electric vehicle
By combining moving average filtering and physical models, the system can judge the change rate of motor speed and load torque in real time and use virtual damping torque control to solve the problems of accuracy and smoothness in identifying and suppressing slippage of two-wheeled electric vehicles on low-traction surfaces, thereby improving the riding experience and safety.
Patent Information
- Application Number
- CN202511856416.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-01-20
AI Technical Summary
Existing anti-slip control technologies for two-wheeled electric vehicles suffer from problems such as lag, misjudgment, and poor riding experience, especially on low-traction surfaces where they are difficult to accurately identify and effectively suppress slippage.
By combining moving average filtering with a physical model, the rate of change of motor speed and load torque are judged in real time. Virtual damping torque is generated using a virtual inertia coefficient, and the torque output is flexibly controlled to achieve accurate identification and smooth suppression of slippage.
It improves the accuracy of slip recognition on low-traction surfaces, enhances riding smoothness and safety, ensures operational response speed and riding continuity, and avoids sudden torque changes and secondary slippage.
Smart Images
Figure CN121361464A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of two-wheeled electric vehicle anti-skid control, and particularly relates to a two-wheeled electric vehicle driving anti-skid control method. BACKGROUND
[0002] With the rapid increase in the number of two-wheeled electric vehicles, the two-wheeled electric vehicles play an increasingly important role in daily commuting and short-distance travel of residents. The two-wheeled electric vehicles have the advantages of simple structure, low cost and convenient use, but have weak safety protection capability. Once out of control or falling down, the driver is easily seriously injured. In the low adhesion conditions such as rain and snow, sandy road surface and slope starting, if the driver sharply twists the accelerator, the driving wheel is prone to slip, which causes the vehicle to suddenly deviate and spin, and the driver even falls down. At the same time, some electric vehicles with energy recovery function may have the rear wheel locked or slip due to excessive braking torque when descending or braking after releasing the accelerator, which also has safety hazards.
[0003] However, the existing two-wheeled electric vehicle driving anti-skid control technology mainly includes two types: one type is a control method based on the speed difference between the front and rear wheels. When the speed difference is detected, the slip has usually occurred, and the control has hysteresis. The other type is a control method based on the parameters of the motor itself, which usually relies on a single acceleration threshold to determine. Due to the high-frequency jitter and noise of the motor speed signal in the actual acquisition process, and the complex change of the road adhesion coefficient, such as the distinction between dry road sudden acceleration and ice slip, the judgment is prone to misjudgment, which misjudges the normal sudden acceleration as slip, or misses the low adhesion road slip, in addition, the simple torque reduction often causes sudden change of power output, causing strong jerk of the vehicle, poor riding experience, and easy to cause slip again when exiting the anti-skid mode due to instantaneous recovery of torque. Therefore, a two-wheeled electric vehicle driving anti-skid control method is proposed. SUMMARY
[0004] The purpose of the present application is to provide a two-wheeled electric vehicle driving anti-skid control method to solve the problems mentioned in the background.
[0005] A two-wheeled electric vehicle driving anti-skid control method, comprising: Step 1: set a plurality of sampling time intervals with fixed sampling time intervals, and obtain the motor speed corresponding to each motor speed at a plurality of continuous sampling time intervals, analyze the motor speed change between adjacent sampling time intervals and the fixed sampling time interval, and obtain the current motor speed change rate of the motor. Step two: according to the current motor speed of the motor, the maximum output torque corresponding to the motor at the speed is obtained by looking up the table, the maximum output torque is divided by the equivalent rotational inertia of the system, the maximum angular acceleration that the vehicle can theoretically reach at the current speed is obtained, and the maximum angular acceleration is multiplied by a preset safety factor slightly greater than 1 to obtain the dynamic acceleration threshold of the motor at the current time; Step three: the real-time torque current of each sampling time is obtained synchronously, the real-time torque current is multiplied by the motor torque constant to obtain the total electromagnetic torque at each sampling time, and the real-time speed change rate is multiplied by the equivalent rotational inertia of the system to obtain the actual inertia consumption torque; finally, the difference between the total electromagnetic torque at each sampling time and the actual inertia consumption torque is obtained as the observed load torque at each sampling time; Step four: according to the handle opening degree of the driver, it is judged whether the vehicle has a driving request, when there is a driving request, according to the determination condition one and the determination condition two, when any of the determination conditions is met, it is judged that the vehicle currently has tire driving slip phenomenon; Step five: when it is determined that the vehicle currently has tire driving slip phenomenon, the controller switches from normal driving mode to anti-slip control mode, multiplies the current motor speed change rate of the motor by the virtual inertia coefficient to obtain the virtual damping torque, obtains the original request torque of the driver, subtracts the virtual damping torque from the original request torque of the driver to obtain the target torque, and analyzes the target torque to obtain a new target torque. Step six: set determination mode one and determination mode two, and determine the conditions for exiting the anti-slip control mode according to the order that determination mode one is prior to determination mode two, when the exit condition is met, the anti-slip control mode is exited and the normal driving mode is restored.
[0006] As a further scheme of the application: the specific way of obtaining the current motor speed change rate of the motor is: The change amount of the motor speed between adjacent sampling times is sequentially obtained and divided by the fixed sampling time interval, the motor speed change rates are added and divided by the total number of change amounts to obtain the current motor speed change rate of the motor.
[0007] As a further scheme of the application: the specific way of judging whether the vehicle has a driving request according to the handle opening degree of the driver is: When the handle opening degree of the driver is greater than 0, it is determined that the vehicle has a driving request, otherwise, it is determined that the vehicle does not have a driving request.
[0008] As a further scheme of the present application, the first determination condition is specifically: when the motor speed variation rate is greater than the dynamic acceleration threshold, it is determined that the vehicle currently has the tire driving slip phenomenon. The second determination condition is specifically: the variation amount of the observed load torque at each sampling time between two adjacent sampling times is obtained and divided by the fixed sampling time interval, to obtain the variation rate of each variation amount, the sum of each variation rate is added and divided by the total number of variation rates, to obtain the observed load torque variation rate, and when the observed load torque variation rate is less than the preset negative drop threshold, it is determined that the vehicle currently has the tire driving slip phenomenon.
[0009] As a further scheme of the present application, the specific way of analyzing the target torque to obtain the new target torque is: When the target torque is negative, the new target torque is limited to zero, and when the target torque is not negative, the target torque is taken as the new target torque.
[0010] As a further scheme of the present application, the first determination mode is specifically: when the driver releases the throttle handle and the original torque request is zero, the first determination mode is entered: the motor speed variation rate is detected, and when the motor speed variation rate is less than the dynamic acceleration threshold, the virtual inertia coefficient is immediately cleared to zero, and the anti-slip control mode is switched to the normal driving mode, otherwise, the second determination mode is entered.
[0011] The second determination mode is specifically: when the driver does not release the throttle handle and the original torque request is not zero, or the driver has released the throttle handle and the original torque request is zero, but the motor speed variation rate is not less than the dynamic acceleration threshold, the difference between the driver's original request torque and the new target torque is calculated, and when the difference between the two is less than the preset convergence threshold within a set time window, the virtual inertia coefficient is slowly reduced to zero, the anti-slip control mode is switched to the normal driving mode, and the set time window is 300 milliseconds.
[0012] The specific way of slowly reducing the virtual inertia coefficient to zero is: The virtual inertia coefficient is uniformly reduced to 0 from the current value within a predetermined time t, instead of instantaneously becoming 0, and the predetermined time t is in the range of 150 milliseconds to 300 milliseconds. If the first determination mode and the second determination mode are not met, the anti-slip control mode is continuously maintained.
[0013] Compared with the prior art, the present application has the following beneficial effects: (1) The application adopts double-channel feature judgment under the premise of driving request, and if the real-time speed change rate exceeds the dynamic threshold, it is determined as violent slipping, the change rate of the observed load torque in the sampling interval is calculated and averaged, and if it is lower than the preset negative drop threshold, it is determined as low adhesion dark sliding, and the acceleration overrun is combined with the load drop to accurately identify the slipping without misjudgment of dry high adhesion strong acceleration, and on the ice surface and other working conditions with no obvious acceleration overrun; (2) The application introduces a virtual inertia coefficient, multiplies it with the motor acceleration to generate a virtual damping torque, deducts the virtual damping torque from the driver torque instruction to obtain the final target torque, the virtual damping increases as the acceleration increases, and the reverse braking is realized; the damping automatically decreases after the acceleration decreases, without cutting off the power, the slipping is flexibly inhibited, and the riding smoothness is improved; (3) The application immediately clears the virtual inertia coefficient when the driver's requested torque is zero and the real-time speed change rate falls below the corresponding dynamic acceleration threshold, and quickly exits the anti-skid to restore normal driving; when there is still torque request or the acceleration has not completely fallen, the difference between the driver's requested torque and the new target torque is monitored within the time window, and if it is less than the preset convergence threshold, the virtual inertia coefficient is slowly attenuated to zero within the preset 150 to 300 milliseconds, and the target torque change rate is limited to smooth transition, otherwise the anti-skid mode is maintained, through two-stage exit and slow-release control, the system responsiveness, riding comfort and safety redundancy are further improved, the operation response speed is ensured, and the continuity and safety of driving are ensured. BRIEF DESCRIPTION OF DRAWINGS
[0014] Figure 1 The figure is a schematic diagram of the method framework structure of the application. DETAILED DESCRIPTION
[0015] The technical solutions of the application will be described in detail below with reference to the embodiments, obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.
[0016] Embodiment one: please refer to Figure 1 The application provides a two-wheeled electric vehicle driving anti-skid control method, comprising the following steps: Step one: set a fixed sampling time interval in the motor controller, set a plurality of continuous sampling time points according to the fixed sampling time interval and number them in turn, obtain the motor speed corresponding to the motor at the plurality of continuous sampling time points respectively, calculate the change of the motor speed between adjacent sampling time points in turn and divide by the fixed sampling time interval, add the motor speed change rates and divide by the total number of changes to obtain the current motor speed change rate of the motor. Through this moving average method, high-frequency jitter and noise in the motor speed measurement can be effectively filtered out, making the subsequent acceleration-based judgment more stable and reliable.
[0017] For example: the fixed sampling time interval is set to 1 millisecond, and the motor speeds at the five continuous sampling time points are 10, 12, 15, 19 and 23 (units are arbitrary speed units) in turn. The speed changes between adjacent sampling time points are 2 / 1 millisecond, 3 / 1 millisecond, 4 / 1 millisecond and 4 / 1 millisecond respectively. Adding the 2 / 1 millisecond, 3 / 1 millisecond, 4 / 1 millisecond and 4 / 1 millisecond and dividing by 4 gives the current motor speed change rate of the motor. In the motor controller, set a fixed sampling time interval and continuously collect the motor speed at multiple time points. The instantaneous change rate is obtained by calculating the speed difference between adjacent sampling time points, and the speed change rates at the continuous sampling points are added and averaged to obtain the smoothed motor speed change rate at the current time. The high-frequency jitter and random noise in the speed measurement caused by vibration, electromagnetic interference or Hall sensor precision limitations during motor operation are effectively filtered out. Compared with directly using instantaneous difference to calculate acceleration, the data after moving average processing can better reflect the real motion trend of the vehicle, providing a stable and reliable data basis for subsequent slip judgment based on acceleration, and avoiding false triggering of the anti-slip function due to signal glitches.
[0018] Step two: according to the current real-time motor speed of the motor, the maximum output torque corresponding to the motor at this speed is obtained by looking up the table, the maximum output torque is divided by the equivalent moment of inertia of the system to obtain the maximum angular acceleration that the vehicle can theoretically reach at the current speed, and the maximum angular acceleration is multiplied by a preset safety factor slightly greater than 1 to obtain the dynamic acceleration threshold of the motor at the current time. The corresponding relationship table between the motor speed and the maximum output torque is established in the controller in advance according to the motor prototype bench test or the motor specification book, and the specific mode is as follows: in the motor prototype test, the motor is tested under loading at different speed points, the output current is gradually increased at each speed point, and the maximum output torque that can be continuously output under the condition that the motor and the inverter are not exceeded is recorded to obtain the maximum output torque data at each speed point; the data is divided according to the speed interval or stored in the controller in the form of speed breakpoints to form a maximum torque curve for table lookup, and when the real-time motor speed at a certain time is obtained, the controller can obtain the maximum torque value that the motor can theoretically output at the speed according to the interval of the speed in the above table or by using an interpolation method. Then, the maximum output torque is divided by the equivalent rotational inertia of the system to obtain the maximum angular acceleration that the vehicle can theoretically reach at the speed; then, the maximum angular acceleration is multiplied by a preset safety factor slightly greater than 1 to obtain the dynamic acceleration threshold at the time; It should be noted that a system equivalent rotational inertia parameter is set at the vehicle level to approximately represent the comprehensive influence of the vehicle mass, the hub, the motor rotor and the like on the acceleration, and the system equivalent rotational inertia parameter is an empirical constant calibrated in advance, representing the rotational inertia characteristics of the vehicle under no load or standard load; It should be noted that the system equivalent rotational inertia can be obtained only by the rotor rotational inertia of the motor itself in the motor prototype bench test or the motor specification book, and the system equivalent rotational inertia is used to represent the comprehensive influence of the motor, the hub, the tire and the vehicle mass and the like on the inertial force in the vehicle acceleration process, and cannot be directly obtained only by the motor bench data. Therefore, in actual application, the system equivalent rotational inertia is usually obtained by theoretical conversion of the vehicle mass and the tire radius, or is obtained by reverse calculation of the equivalent rotational inertia under the condition that the motor output torque is known through the vehicle acceleration test, and the final inertia parameter is calibrated in the controller in the form of an empirical constant: According to the current real-time motor speed of the motor, the maximum output torque corresponding to the speed of the motor is obtained by table lookup, the maximum output torque value is divided by the system equivalent rotational inertia to obtain the maximum angular acceleration that the vehicle can reach under the maximum output torque; to avoid misjudgment caused by model error or environmental change, the maximum angular acceleration is multiplied by a preset safety factor slightly greater than 1, and the preset safety factor is in the range of 1.1-1.3 to obtain the dynamic acceleration threshold of the motor at the current time; The relationship between the rotation speed and the maximum output torque is established based on the physical characteristics of the motor. The controller obtains the corresponding output torque according to the real-time rotation speed lookup table, and combines the pre-calibrated equivalent rotational inertia of the system to calculate the physical limit acceleration that the vehicle can theoretically achieve under the current working condition. Multiply the limit value by a safety factor to get the dynamic acceleration threshold for determining the slip. The threshold is not a fixed constant, but changes dynamically with the motor speed and physical limit. This solves the problem of inconsistent acceleration characteristics at low and high speeds. The threshold calculated by the physical model represents the maximum possible acceleration when the vehicle has good traction. If the measured acceleration exceeds this value, it is certain that the motor is idling. This fundamentally distinguishes between high-torque rapid acceleration with good traction and rapid rotation caused by slipping, ensuring that the anti-slip function is not triggered by mistake when accelerating rapidly on dry roads.
[0019] Step three: Synchronously obtain the real-time torque current of the motor at each sampling time, i.e. the q-axis current. Multiply the real-time torque current by the motor torque constant to get the total electromagnetic torque at each sampling time. At the same time, multiply the real-time rotation speed change rate obtained in step one by the equivalent rotational inertia of the system to get the actual inertia consumption torque. Finally, subtract the actual inertia consumption torque from the total electromagnetic torque at each sampling time to get the observed load torque at each sampling time. First, according to the motor control principle, the electromagnetic torque is proportional to the current. In order to build an accurate disturbance observer, the controller synchronously records the real-time torque current of the motor at the same sampling time when collecting the motor speed. Multiply the real-time torque current by the motor torque constant to get the total electromagnetic torque at each sampling time. Second, multiply the real-time rotation speed change rate obtained in step one by the equivalent rotational inertia of the system to get the actual inertia consumption torque. It should be noted that in order to ensure the consistency of the calculation dimension, the motor speed involved in the above calculation has been converted to angular speed (rad / s), and the current involved has been converted to effective value, ensuring that the calculated torque is in units of Newton-meters (N·m).
[0020] Finally, subtract the inertia consumption torque from the total electromagnetic torque at each sampling time to get the observed load torque at each sampling time. This physical quantity directly reflects the traction between the wheels and the ground at each sampling time, and is used to reflect the current road adhesion.
[0021] The total electromagnetic torque is calculated by multiplying the real-time torque current of the motor by the motor torque constant, and the inertia consumption torque is calculated by multiplying the real-time rotation speed change rate by the equivalent rotational inertia of the system. The difference between the two is the observed external load torque, which is directly related to the adhesion between the tire and the ground. A large load torque indicates good traction, and a sudden decrease in load torque indicates that the road has become slippery or the tire has lost traction, providing key data support for identifying low-adhesion roads.
[0022] Step four: comparing the motor speed change rate obtained in step one with the dynamic acceleration threshold value obtained in step two, obtaining the change amount of the observed load torque at each sampling time in step three between adjacent sampling times, obtaining the observed load torque change rate according to the change amount, performing multi-dimensional feature analysis on the vehicle operating state, and comprehensively analyzing the motor speed change rate and the observed load torque under the premise that the vehicle has an acceleration request to determine whether the vehicle currently has a tire driving slip phenomenon; First, it is determined whether there is a driving request, for example, whether the throttle handle opening is greater than a certain minimum value, whether the target torque instruction is greater than zero, etc. The slip determination logic is started only when there is a clear acceleration intention. When the handle opening of the driver is greater than 0, i.e., there is a driving request, if any of the following determination conditions is met, it is determined that the vehicle is in a slip state; Determination condition one: if the motor speed change rate is greater than the dynamic acceleration threshold value, it means that the acceleration is abnormally large at the current speed, and the driving force is too large to cause slip, which is considered as a violent slip feature, and it is determined that the vehicle currently has a tire driving slip phenomenon; Determination condition two: the change amount of the observed load torque at each sampling time between two adjacent sampling times is calculated and divided by a fixed sampling time interval to obtain the change rate of each change amount. The sum of the change rates is added and then divided by the total number of change rates to obtain the observed load torque change rate. When the observed load torque change rate is less than a preset negative drop threshold value, it means that the observed load torque decreases rapidly and greatly, i.e., the load change rate is less than the preset negative drop threshold value, indicating that the frictional resistance of the tire to the ground suddenly decreases, which is considered as a low adhesion slip feature. This represents the feature of the vehicle driving into an ice surface or other low adhesion road surface, and the resistance disappears instantaneously. Therefore, it can be determined that the vehicle has a tire driving slip. The absolute value of the negative drop threshold value should be calibrated through low adhesion road surface verification data, and the value range is 0.1-0.2 N·m, representing the rapid change of the adhesion of the wheel to the ground. When any of the above two types of features meets the determination condition, it is determined that the vehicle has a tire driving slip; Under the premise that there is a driving request, dual-channel feature determination is adopted. If the real-time speed change rate exceeds the dynamic threshold value, it is determined as violent slip. The change rate of the observed load torque between samples is calculated and averaged. If it is lower than the preset negative drop threshold value, it is determined as low adhesion dark slip. The combination of acceleration overrun and load drop can accurately identify slip in ice and other working conditions without misjudgment of dry high adhesion strong acceleration, and is sensitive and robust.
[0023] Step five: after determining that the vehicle has occurred in the tire driving slip state, the controller immediately switches from the normal driving mode to the anti-slip control mode, and obtains a final target torque by multiplying the current motor speed change rate of the motor by a virtual inertia coefficient according to the current motor speed change rate of the motor, subtracting the virtual damping torque from the original request torque of the driver to obtain the final target torque containing the virtual damping term, and controlling the motor to execute; First, a virtual inertia coefficient is preset, and when the controller switches to the anti-slip control mode, the virtual inertia coefficient is assigned a larger initial set value, which is used to adjust the strength of the virtual damping. A basic value is generally set during factory calibration, and it can also be adjusted by real vehicle calibration. According to the current motor speed change rate of the motor obtained in step one, the virtual damping torque is obtained by multiplying the current motor speed change rate of the motor by the virtual inertia coefficient. The virtual damping torque is proportional to the motor acceleration in mathematical form, and can be equivalent to a larger virtual rotational inertia superimposed on the motor shaft, thereby providing a reverse restraining effect when the motor speed rises rapidly. The virtual inertia coefficient is an empirical calibration parameter for generating a virtual damping torque. Its acquisition method is as follows: first, determine the basic value of the virtual inertia coefficient according to the equivalent rotational inertia of the vehicle system, which is usually 2-10 times the equivalent rotational inertia; then correct the basic value through acceleration test of the vehicle on low adhesion road surface, so that it can provide sufficient inhibition when the vehicle appears to slip; finally, store the corrected virtual inertia coefficient in the controller as a fixed parameter.
[0024] According to the current motor speed change rate of the motor obtained in step one, the virtual damping torque is obtained by multiplying the current motor speed change rate of the motor by the virtual inertia coefficient. The virtual damping torque physically simulates a large flywheel exerting a reverse resistance on the motor shaft, and the resistance is proportional to the acceleration. The direction of the virtual damping torque is opposite to that of the acceleration, i.e. when the motor speed rises rapidly, the damping torque plays a reverse restraining effect. Get the original request torque of the driver, subtract the virtual damping torque from the original request torque of the driver to obtain the target torque, and perform non-negative limit processing on the target torque to obtain a new target torque. The controller obtains the original torque requested by the driver through the accelerator as the original request torque of the driver. After subtracting the virtual damping torque from the original request torque of the driver, the target torque is obtained. If the target torque is negative, the new target torque is limited to zero and sent to the motor control module to avoid reverse driving. If the target torque is not negative, the target torque value is sent to the motor control module as the new target torque, which is further converted into a current command for closed-loop control. By introducing a virtual inertia coefficient, a virtual damping torque is generated by multiplying the motor acceleration, and the virtual damping torque is deducted from the driver torque command to obtain the final target torque. The greater the acceleration, the greater the virtual damping, which realizes reverse braking. When the acceleration decreases, the damping automatically decreases, without the need to cut off the power, which can flexibly suppress the slip and improve the riding smoothness. Compared with directly cutting off the power or fixed proportion flow limiting, this method realizes automatic adjustment of the torque by simulating physical damping. The more serious the slip, the greater the damping, and the damping automatically decreases when the slip disappears, avoiding the phenomenon of sudden stop and sudden start in traditional control. While suppressing the slip, part of the driving force is retained to help the vehicle drive out of the slippery area.
[0025] Under the fixed sampling period, the motor speed is differentiated and moving average is performed to obtain the noise-reduced speed change rate; the maximum torque in each speed point torque is obtained according to the real-time speed lookup table, and the dynamic acceleration threshold is formed by combining the system equivalent moment of inertia and multiplying a safety factor; the product of the real-time torque current of the motor and the motor torque constant is taken as the total electromagnetic torque, and the inertia consumption torque obtained by the speed change rate and the system equivalent moment of inertia is deducted to construct the observed load torque; when there is a driving request, if the speed change rate exceeds the dynamic threshold or the average change rate of the observed load torque is lower than the negative drop threshold, the slip is determined and the anti-slip control is cut in, a virtual damping torque is generated by a virtual inertia coefficient x speed change rate, and the virtual damping torque is deducted from the driver requested torque to obtain the final target torque for closed-loop execution.
[0026] By moving average filtering and dynamic threshold setting based on physical limits, the technical problems of traditional sensorless schemes being easily disturbed by signal noise and misjudging the sudden acceleration on dry road as slip are effectively solved. At the same time, the observed load torque change rate is introduced as a supplementary judgment basis, which greatly improves the recognition ability of the vehicle on ice and other low adhesion roads. In the control strategy, the virtual damping torque is used instead of the harsh power-off or current limiting, which simulates the smooth characteristics of physical large inertia, realizes the flexible automatic adjustment of the torque, avoids the jerk of the vehicle, and retains the necessary driving force while effectively suppressing the slip, thereby improving the riding smoothness and safety.
[0027] Embodiment two: as the second embodiment of the present application, compared with embodiment one, the technical solution of the present embodiment is only different from that of embodiment one in that the present embodiment further comprises step six. Step six: set the determination mode one and the determination mode two, and determine the conditions for exiting the anti-slip control mode in the order that the determination mode one is prior to the determination mode two. When the exit condition is met, the anti-slip control mode is exited and the normal driving mode is restored. The first and second determination modes are set, and the conditions for exiting the anti-slip control mode are determined according to the priority order of the determination modes, and when the exit condition is met, the normal torque control mode is switched back smoothly, and the anti-slip control process is completed; The system executes the following two determination modes according to the priority order; When the driver releases the throttle handle and the original torque request is zero, the first determination mode is entered: the motor speed change rate is detected, and when the motor speed change rate has fallen below the dynamic acceleration threshold value, i.e., the motor speed change rate is less than the dynamic acceleration threshold value, it indicates that the wheels are no longer in an out-of-control idling state, and the virtual inertia coefficient is immediately cleared to zero, switching from the anti-slip control mode to the normal driving mode, ensuring that the system is in an initial standby state when the throttle is twisted next time; When the motor speed change rate has fallen below the dynamic acceleration threshold value corresponding to the current motor speed, i.e., the motor speed change rate is less than the dynamic acceleration threshold value, it indicates that the wheels are no longer in an out-of-control idling or significant slip state, and the controller immediately clears the virtual inertia coefficient to zero, switching from the anti-slip control mode to the normal driving mode, ensuring that the system is in an initial standby state when the driver twists the throttle handle again, and re-performs anti-slip judgment, otherwise, the second determination mode is entered: When the driver does not release the throttle handle and the original torque request is not zero, or the driver has released the throttle handle and the original torque request is zero, but the motor speed change rate is still greater than or equal to the dynamic acceleration threshold value, it indicates that the wheel speed change is still large, and there is a risk of residual slip or inertial idling, then the second determination mode is entered; In the second determination mode, the difference between the driver's original requested torque and the new target torque is calculated, and when the difference between the two is less than the preset convergence threshold value within a set time window, it indicates that there is no new slip trend in the recent period of time, which indicates that the virtual damping torque is very small, and the vehicle has stabilized and is close to the normal driving state, and the vehicle has approached the normal driving state, the controller slowly reduces the virtual inertia coefficient to zero, switching from the anti-slip control mode to the normal driving mode, and if the above conditions are not met, the anti-slip control mode is continuously maintained, and the length of the set time window is 30-50 milliseconds; The specific way for the controller to slowly reduce the virtual inertia coefficient to zero is to uniformly reduce the virtual inertia coefficient from the current value to 0 within a predetermined time t, rather than instantaneously changing to 0, thereby avoiding the vehicle jerk caused by sudden torque changes, and the predetermined time t is in the range of 150-300 milliseconds; The specific value of the preset convergence threshold value is determined by relevant personnel according to actual needs; When the torque difference is determined to be less than the torque difference threshold value in mode two for a set time window, the controller starts to slowly reduce the virtual inertia coefficient to zero at a preset time length, and limits the change rate of the final target torque in the process of reducing the virtual inertia coefficient, so that the torque recovery process is smooth and continuous, and a new torque mutation caused by mode switching is avoided. When the virtual inertia coefficient is linearly reduced from the current value to zero at the preset time length, and the new target torque and the original requested torque of the driver remain consistent for a long time, the system determines that the vehicle has stabilized, and the smooth switching from the anti-slip control mode to the normal driving mode is completed. After observation in the set time window, the actual output torque is almost equal to the driver's requested torque, and the speed change is smooth without sharp fluctuations. The system determines to exit the anti-slip control mode according to this, and the subsequent vehicle acceleration is completely controlled by the driver's handle. The riding experience is natural and smooth. When the virtual inertia coefficient decays to zero and the new target torque and the original requested torque of the driver remain consistent for a long time, the switching from the anti-slip control mode to the normal driving mode is completed. If the above conditions are not met, the anti-slip control mode is continuously maintained. If the driver releases the accelerator or the speed change rate has returned to normal, the coefficient is immediately exited and cleared, preparing for the next acceleration. If the driver does not release the accelerator, the difference between the actual output torque and the requested torque is monitored. If the difference converges within a period of time, it indicates that the system has stabilized, and the virtual inertia coefficient is linearly decreased to zero within 150-300 ms. If the anti-slip is exited instantaneously, the motor torque will suddenly recover to the maximum, which will cause the vehicle to slip again under the condition that the road surface is still wet. Linear exit ensures smooth transition of power, distinguishes between the driver's active stop intention and the vehicle's automatic stabilization process, and guarantees the response speed of operation, as well as the continuity and safety of travel. When the driver's requested torque is zero and the real-time speed change rate falls below the corresponding dynamic acceleration threshold value, the virtual inertia coefficient is immediately cleared to zero, and the anti-slip is quickly exited to return to normal driving. When there is still a torque request or the acceleration has not completely fallen, the difference between the driver's requested torque and the new target torque is monitored within a time window to determine whether it is continuously less than a preset convergence threshold value. If it is, the virtual inertia coefficient is slowly decayed to zero within a preset time length of 150 to 300 milliseconds, and the target torque change rate is limited to smooth the transition. Otherwise, the anti-slip mode is maintained. Through two-stage exit and slow-release control, the system can quickly and smoothly return to regular driving without introducing torque mutation and secondary slipping, further improving system responsiveness, riding comfort, and safety redundancy.
[0028] Embodiment three: As an embodiment of the present application, in specific implementation, compared to embodiment one and embodiment two, the technical solution of the present embodiment is to combine the solutions of embodiment one and embodiment two.
[0029] The above formulas are all dimensionless values calculated, the formulas are obtained by collecting a large amount of data to simulate a formula of the most recent real situation, and preset parameters and threshold values in the formulas are set by a person skilled in the art according to actual conditions.
[0030] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. A two-wheel electric vehicle drive slip control method characterized by, Comprise: Step one: set multiple sampling time points with fixed sampling time interval, obtain the motor speed corresponding to the motor at the continuous multiple sampling time points, analyze the motor speed change between adjacent sampling time points and the fixed sampling time interval, and obtain the current motor speed change rate of the motor; Step two: according to the current real-time motor speed of the motor, the maximum output torque corresponding to the motor at the speed is obtained, the maximum output torque is divided by the equivalent rotational inertia of the system, the maximum angular acceleration of the vehicle at the current speed is obtained, and the maximum angular acceleration is multiplied by the preset safety factor to obtain the current dynamic acceleration threshold of the motor; Step three: the real-time torque current of each sampling time point is obtained synchronously, the real-time torque current is multiplied by the motor torque constant, which is used as the total electromagnetic torque of each sampling time point, at the same time, the real-time speed change rate is multiplied by the equivalent rotational inertia of the system to obtain the actual inertia consumption torque; finally, the difference between the total electromagnetic torque of each sampling time point and the actual inertia consumption torque is obtained as the observed load torque of each sampling time point; Step four: according to the handle opening degree of the driver, it is judged whether the vehicle exists driving request, when the driving request exists, according to the determination condition one and the determination condition two, when any one of the determination conditions is met, it is judged that the vehicle currently exists tire driving slip phenomenon; Step five: when it is judged that the vehicle currently exists tire driving slip phenomenon, the controller is switched from normal driving mode to anti-slip control mode, the current motor speed change rate of the motor is multiplied by the virtual inertia coefficient to obtain the virtual damping torque, the original request torque of the driver is obtained, the original request torque of the driver is subtracted from the virtual damping torque to obtain the target torque, and the target torque is analyzed to obtain the new target torque; Step six: set determination mode one and determination mode two, according to the order that determination mode one is prior to determination mode two, the conditions for exiting the anti-slip control mode are determined, when the exit condition is met, the anti-slip control mode is exited and the normal driving mode is restored.
2. The drive slip control method of a two-wheeled electric vehicle according to claim 1, characterized by, The specific way to obtain the current motor speed change rate of the motor is: The change of the motor speed between adjacent sampling time points is calculated in turn and divided by the fixed sampling time interval, the motor speed change rates are added and divided by the total number of changes to obtain the current motor speed change rate of the motor.
3. The drive slip control method of a two-wheeled electric vehicle according to claim 2, characterized by, The specific way to judge whether the vehicle exists driving request according to the handle opening degree of the driver is: When the handle opening degree of the driver is greater than 0, it is determined that the vehicle exists driving request, otherwise, it is determined that the vehicle does not exist driving request.
4. The drive slip control method of a two-wheeled electric vehicle according to claim 3, characterized by, The specific determination condition one is: When the motor speed change rate is greater than the dynamic acceleration threshold, it is judged that the vehicle currently exists tire driving slip phenomenon.
5. The drive slip control method of a two-wheeled electric vehicle according to claim 4, characterized by, The specific determination condition two is: The change of the observed load torque at each sampling time point between two adjacent sampling time points is obtained and divided by the fixed sampling time interval to obtain the change rate of each change, the sum of the change rates is added and divided by the total number of change rates to obtain the observed load torque change rate, when the observed load torque change rate is less than the preset negative drop threshold, it is judged that the vehicle currently exists tire driving slip phenomenon.
6. The drive slip control method of a two-wheeled electric vehicle according to claim 1, characterized by, The specific way to analyze the target torque to obtain the new target torque is: When the target torque is negative, the new target torque is limited to zero, and when the target torque is not negative, the target torque is taken as the new target torque.
7. The drive slip control method of a two-wheeled electric vehicle according to claim 1, characterized by, The determination mode one is specifically: When the driver releases the throttle grip and the original torque request is zero, the determination mode one is entered: the motor speed change rate is detected, and when the motor speed change rate is less than the dynamic acceleration threshold, the virtual inertia coefficient is immediately cleared to zero, and the anti-slip control mode is switched to the normal driving mode, otherwise, the determination mode two is entered.
8. The drive slip control method of a two-wheeled electric vehicle according to claim 7, characterized by, The determination mode two is specifically: When the driver does not release the throttle grip and the original torque request is not zero, or the driver has released the throttle grip and the original torque request is zero, but the motor speed change rate is not less than the dynamic acceleration threshold, the difference between the driver's original request torque and the new target torque is calculated, and when the difference between the two is less than the preset convergence threshold within the set time window, the virtual inertia coefficient is slowly reduced to zero, the anti-slip control mode is switched to the normal driving mode, and the set time window is 30-50 milliseconds in length.
9. The drive slip control method of a two-wheeled electric vehicle according to claim 8, characterized by, The specific way of slowly reducing the virtual inertia coefficient to zero is: The virtual inertia coefficient is uniformly reduced from the current value to 0 within a predetermined time t, rather than instantaneously becoming 0, and the predetermined time t is in the range of 150-300 milliseconds.
10. The drive slip control method of a two-wheeled electric vehicle according to claim 9, characterized by, If neither the determination mode one nor the determination mode two is met, the anti-slip control mode is continuously maintained.