Anti-skid control method and device for power-assisted bicycle, power-assisted bicycle and storage medium

Abstract

The application is suitable for the technical field of power-assisted bicycles, and provides a power-assisted bicycle anti-skid control method and device, a power-assisted bicycle and a storage medium. The power-assisted bicycle is provided with a middle motor. The method comprises the following steps: when the power-assisted bicycle is in a trolley mode, the actual output torque of the middle motor of the power-assisted bicycle is acquired; it is judged whether the actual output torque is greater than a torque threshold value, the torque threshold value being calculated in real time through the slope, the chain transmission ratio and the driving wheel friction coefficient of the power-assisted bicycle, the driving wheel friction coefficient being the friction coefficient between the driving wheel and the current road surface of the bicycle; when it is determined that the actual output torque is greater than the torque threshold value, first torque control is performed on the middle motor, and after the first torque control is finished, the actual output torque is less than or equal to the torque threshold value. The application can reduce the probability of power-assisted bicycle skidding.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power-assisted bicycles, and particularly relates to a power-assisted bicycle anti-skid control method and device, a power-assisted bicycle and a computer readable storage medium. BACKGROUND

[0002] Power-assisted bicycle skidding refers to a phenomenon that the power-assisted bicycle cannot normally travel according to the intention of the driver due to the decrease in friction between the power-assisted bicycle and the ground caused by wet and slippery road surface, rapid acceleration and uphill, etc. when the power-assisted bicycle travels. When the power-assisted bicycle skids, it may deviate from the predetermined route, and forward sliding, side sliding or even rotation may occur, which seriously affects the driving safety.

[0003] At present, the phenomenon of vehicle skidding is usually controlled by reducing the speed. However, in fact, the reason for the skidding of the power-assisted bicycle in the push mode is irrelevant to the vehicle speed, and the current way of controlling vehicle skidding is not applicable to the skidding of the power-assisted bicycle in the push mode. SUMMARY

[0004] The power-assisted bicycle anti-skid control method and device, the power-assisted bicycle and the storage medium provided by the embodiments of the application can reduce the probability of power-assisted bicycle skidding.

[0005] In a first aspect, the embodiments of the application provide a power-assisted bicycle anti-skid control method, comprising:

[0006] When the power-assisted bicycle is in the push mode, the actual output torque of the middle motor is acquired.

[0007] It is judged whether the actual output torque is greater than a torque threshold value, the torque threshold value being calculated in real time according to the chain transmission ratio corresponding to the power-assisted bicycle and the adhesion between the power-assisted bicycle and the road surface, and reflecting the maximum torque that the middle motor can output in the case that the power-assisted bicycle does not skid;

[0008] When it is determined that the actual output torque is greater than the torque threshold value, the first torque control is performed on the middle motor, and after the first torque control is ended, the torque output by the middle motor in real time is less than or equal to the torque threshold value.

[0009] In a second aspect, the embodiments of the application provide a power-assisted bicycle anti-skid control device, the power-assisted bicycle being provided with a middle motor, comprising:

[0010] An actual output torque determination module is configured to acquire the actual output torque of the middle motor when the power-assisted bicycle is in the push mode.

[0011] determining module, configured to determine whether the actual output torque is greater than a torque threshold, the torque threshold being calculated in real time according to a chain transmission ratio of the power-assisted bicycle and adhesion between the power-assisted bicycle and the road surface, and reflecting a maximum torque that the middle motor can output in a case that the power-assisted bicycle does not slip;

[0012] a first torque control module, configured to perform first torque control on the middle motor when it is determined that the actual output torque is greater than the torque threshold, and the torque output by the middle motor in real time after the first torque control is completed is less than or equal to the torque threshold.

[0013] In a third aspect, an embodiment of the present application provides a power-assisted bicycle, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements steps of the power-assisted bicycle anti-slip control method in the first aspect when executing the computer program.

[0014] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, and the computer readable storage medium stores a computer program, and the computer program implements steps of the power-assisted bicycle anti-slip control method in the first aspect when executed by a processor.

[0015] In a fifth aspect, an embodiment of the present application provides a computer program product, and when the computer program product is executed on a power-assisted bicycle, the power-assisted bicycle executes the power-assisted bicycle anti-slip control method in the first aspect.

[0016] Compared with the prior art, the embodiment of the present application has the following beneficial effects:

[0017] In the embodiment of the present application, after the actual output torque of the middle motor of the power-assisted bicycle is obtained, it is first determined whether the actual output torque is greater than a torque threshold, and the middle motor is controlled in a first torque control mode after it is determined that the actual output torque is greater than the torque threshold. Since the torque threshold is calculated in real time according to the chain transmission ratio of the power-assisted bicycle and the adhesion, and reflects the maximum torque that the middle motor can output when the power-assisted bicycle does not slip, that is, when the torque output by the middle motor of the power-assisted bicycle is less than or equal to the torque threshold, the power-assisted bicycle does not slip, therefore, when it is determined that the actual output torque is greater than the torque threshold, that is, the probability of the power-assisted bicycle slipping is relatively high, the torque output by the middle motor of the power-assisted bicycle can be directly adjusted to a value less than or equal to the torque threshold through the first torque control, so that the phenomenon of the power-assisted bicycle slipping can be quickly and effectively controlled. Moreover, the driving speed of the power-assisted bicycle and the braking do not need to be reduced in the control process, effectively ensuring the user driving experience and driving safety. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced.

[0019] Figure 1 is a flow diagram of a power-assisted bicycle anti-skid control method provided by an embodiment of the present application;

[0020] Figure 2 is a flow diagram of determining a road surface friction coefficient provided by an embodiment of the present application;

[0021] Figure 3 is a structural diagram of a power-assisted bicycle anti-skid control device provided by an embodiment of the present application;

[0022] Figure 4 is a structural diagram of a power-assisted bicycle provided by an embodiment of the present application. DETAILED DESCRIPTION

[0023] In the following description, for the purpose of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

[0024] It should be understood that the term "comprising" as used in the specification and in the claims indicates the presence of the recited features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0025] It should also be understood that the term "and / or" as used in the specification and in the claims indicates any combination of one or more of the associated listed items and all possible combinations of the items.

[0026] In addition, in the description of the specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0027] Reference to "one embodiment" or "some embodiments" or "one implementation" or "some implementations" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" or "in some embodiments" or "in one implementation" or "in some implementations" in various places in the specification are not necessarily all referring to the same embodiment, but can refer to different embodiments.

[0028] Embodiment one:

[0029] Figure 1 A flowchart of a method for preventing a power-assisted bicycle from slipping is shown. The power-assisted bicycle has a mid-drive motor. The method is described as follows:

[0030] Step S101, when the power-assisted bicycle is in a cart mode, the actual output torque of the mid-drive motor is obtained.

[0031] The power-assisted bicycle refers to a personal transportation vehicle that combines a traditional bicycle and an electric motor. The electric motor is powered by a built-in battery to provide power assistance to the rider.

[0032] The cart mode refers to a mode of travel that includes human-powered driving, such as a walking assistance mode or a power-assisted mode.

[0033] Torque refers to a moment of force that causes an object to rotate. The torque output by the motor of a power-assisted bicycle is a measure of the rotational force that the motor can generate during operation.

[0034] When the torque output by the mid-drive motor of a power-assisted bicycle is transmitted to the wheels, it can be converted into driving force to propel the power-assisted bicycle forward or backward. However, if the driving force exceeds the adhesion between the power-assisted bicycle and the ground, the tires of the power-assisted bicycle will typically slip. Therefore, in the present embodiment, the actual output torque of the mid-drive motor of the power-assisted bicycle is obtained to determine whether the power-assisted bicycle is slipping based on the actual output torque.

[0035] Step S102, determine whether the actual output torque is greater than a torque threshold. The torque threshold is calculated in real time based on the chain ratio corresponding to the power-assisted bicycle and the adhesion between the power-assisted bicycle and the road surface. It reflects the maximum torque that the mid-drive motor can output without slipping.

[0036] The torque threshold is determined according to the maximum torque that the middle motor can theoretically output under the condition that the power-assisted bicycle does not slip, so as to ensure that the power-assisted bicycle does not slip when the torque output by the middle motor is less than or equal to the torque threshold.

[0037] The maximum torque is determined according to the adhesion between the power-assisted bicycle and the road surface and the chain transmission ratio corresponding to the power-assisted bicycle, the adhesion being the friction generated between the tire of the power-assisted bicycle and the road surface, and the chain transmission ratio reflecting the rotation speed ratio of the output shaft of the middle motor to the driving wheel. Alternatively, the chain transmission ratio can be determined according to the technical specifications of the power-assisted bicycle or manual measurement and calculation.

[0038] Since the torque output by the middle motor needs to be transmitted to the driving wheel through the transmission components such as the chain, the actual torque transmitted to the driving wheel is affected by the transmission ratio of the transmission components, and therefore, in order to ensure the accuracy of the torque threshold, the torque threshold corresponding to the middle motor needs to be calculated in combination with the transmission ratio of the transmission components. In the embodiment of the present application, the transmission components of the electric bicycle include the chain. It can be understood that, in actual application, the torque threshold corresponding to the middle motor needs to be calculated in combination with the type of the power-assisted bicycle and the actual transmission components of the power-assisted bicycle when the power-assisted bicycle is other types of power-assisted bicycles or uses other transmission components.

[0039] In the embodiment of the present application, since the power-assisted bicycle does not slip when the actual output torque of the middle motor of the power-assisted bicycle is less than or equal to the set torque threshold, the power-assisted bicycle can be quickly and accurately determined to slip according to whether the actual output torque is greater than the torque threshold, so that corresponding measures can be taken to control the slipping phenomenon of the power-assisted bicycle in a timely manner when the power-assisted bicycle is determined to slip.

[0040] In step S103, when it is determined that the actual output torque is greater than the torque threshold, the first torque control is performed on the middle motor, and after the first torque control is completed, the torque output by the middle motor in real time is less than or equal to the torque threshold.

[0041] Since the power-assisted bicycle usually slips when the actual output torque is greater than the torque threshold, in order to effectively control the slipping of the power-assisted bicycle, if the actual output torque is greater than the torque threshold, the first torque control is performed on the motor of the power-assisted bicycle, that is, the torque output by the motor of the power-assisted bicycle is reduced, so that the torque output by the middle motor of the power-assisted bicycle in real time (i.e., the latest actual output torque) is reduced to the torque threshold or less than the torque threshold, so as to control the slipping phenomenon of the power-assisted bicycle.

[0042] In some embodiments, due to external factors, the torque output by the middle motor in real time may be affected and increased to a value greater than the torque threshold value again within a period of time after the first torque control of the motor, so as to ensure the effect of the anti-slip control, and the actual output torque of the motor can be determined again after a first preset time (for example, 30 seconds) after the first torque control of the motor, to determine whether the actual output torque is still greater than the torque threshold value. If it is determined whether the actual output torque is still greater than the torque threshold value, the first torque control of the motor can be returned to, to ensure that the actual output torque is less than or equal to the torque threshold value.

[0043] In the embodiments of the present application, after the actual output torque of the middle motor of the assist bicycle is obtained, it is first determined whether the actual output torque is greater than the current torque threshold value, and the first torque control of the motor is performed after it is determined that the actual output torque is greater than the torque threshold value. Since the torque threshold value is calculated in real time according to the chain transmission ratio and the adhesion of the assist bicycle, it can reflect the maximum torque that can be output by the middle motor of the assist bicycle when the assist bicycle does not slip, that is, when the actual output torque of the middle motor of the assist bicycle is less than or equal to the torque threshold value, the assist bicycle does not slip, and when the actual output torque is greater than the torque threshold value, the assist bicycle usually slips, so when it is determined that the actual output torque is greater than the torque threshold value, that is, the probability of slipping of the assist bicycle is relatively high, the torque output by the middle motor of the assist bicycle can be directly adjusted to a value less than or equal to the torque threshold value through the first torque control, so that the phenomenon of slipping of the assist bicycle can be quickly and effectively controlled. In the control process, the speed of the assist bicycle does not need to be reduced and the braking does not need to be performed, and the difficulty of pushing the bicycle by the user can be reduced, and the user's riding experience and safety can be effectively ensured.

[0044] In some embodiments, after the step S103, the method further comprises:

[0045] In the case where the torque output by the middle motor in real time is less than or equal to the torque threshold value, the actual speed of the drive wheel of the assist bicycle is determined, and the actual speed reflects the current actual speed of the drive wheel of the assist bicycle.

[0046] In the case where the actual speed is less than the expected speed, the speed control of the middle motor is performed, the speed control is used to increase the output speed of the middle motor, and the expected speed is the expected speed of the drive wheel.

[0047] Optionally, the expected speed can be a speed set by the user or a speed determined according to the gear of the assist bicycle, and the embodiments of the present application do not make specific limitations in this regard.

[0048] To further ensure the user driving experience, if the latest actual output torque is less than or equal to the torque threshold, i.e., the power-assisted bicycle does not slip, the actual speed of the driving wheel of the power-assisted bicycle at the latest actual output torque can be obtained to obtain the actual speed of the driving wheel.

[0049] Optionally, when obtaining the actual speed of the driving wheel of the power-assisted bicycle, the actual speed of the driving wheel can be obtained by a wheel speed sensor or a wheel speed meter, or can be obtained by a related electronic system such as an on-board diagnostic system.

[0050] After obtaining the actual speed of the driving wheel, it can be determined whether the current speed of the driving wheel of the power-assisted bicycle has reached the expected speed, so that when it is determined that the speed of the driving wheel of the power-assisted bicycle does not reach the expected speed, the speed of the motor of the power-assisted bicycle is controlled (first speed control) in time to increase the output speed of the motor so that the speed of the driving wheel of the power-assisted bicycle reaches the expected speed as soon as possible.

[0051] Optionally, when the speed of the motor of the power-assisted bicycle is controlled, the output speed of the motor can be adjusted by changing the output current or output voltage of the internal controller of the motor, changing the duty cycle of the PWM signal, or field-oriented control (FOC), so that the output speed of the motor increases.

[0052] In other embodiments, when the actual speed is greater than the expected speed, and the speed deviation between the actual speed and the expected speed is greater than the speed deviation threshold (such as 2 revolutions per second), to ensure driving safety, the motor can be controlled according to the speed deviation (second torque control) to reduce the output speed of the motor, so that the actual speed of the driving wheel is kept within a safe speed range based on the expected speed.

[0053] In some embodiments, after the speed of the motor is controlled, or after a second preset time (such as 20 seconds) after the speed of the motor is controlled, it can be determined whether the real-time actual speed of the driving wheel is still less than the expected speed. If it is determined that the real-time actual speed is still less than the expected speed, the motor can be controlled to return to the speed control step until the real-time actual speed is greater than or equal to the expected speed.

[0054] In the embodiments of the present application, on the basis that the power-assisted bicycle does not slip, it is further determined whether the actual speed of the driving wheel of the power-assisted bicycle has reached the expected speed, and when it is determined that the actual speed has not reached the expected speed, the output speed of the motor is increased in time, which can improve the driving speed of the power-assisted bicycle as much as possible on the basis of no slip, thereby improving the control effect of the power-assisted bicycle, reducing the difficulty of the user pushing the cart, and effectively improving the user driving experience.

[0055] In some embodiments, the above steps perform speed control on the above-mentioned in-wheel motor, including:

[0056] The target control signal is calculated according to the speed deviation between the actual speed and the expected speed and a PID control algorithm.

[0057] The speed output by the in-wheel motor is adjusted by using the target control signal.

[0058] The PID control algorithm (Proportion Integral Differential) is a control algorithm that combines proportion, integral and differential in one, which can adjust control parameters according to the change of system characteristics, has good adaptive ability, and can effectively suppress overshoot while quickly responding to adjustment requirements, making the adjustment process smoother.

[0059] In the embodiments of the present application, when the in-wheel motor needs to be controlled, the speed deviation between the actual speed and the expected speed can be determined first, and then the control amount corresponding to the speed deviation can be calculated by using the PID algorithm. The control amount can include a proportional term, an integral term and a differential term.

[0060] After obtaining the control amount corresponding to the speed deviation, the target control signal of the in-wheel motor can be determined according to the control amount, and the in-wheel motor can be controlled by using the target control signal, so as to adjust the speed output by the in-wheel motor.

[0061] Optionally, when the target control signal is determined according to the control amount, the target control signal can be determined according to the sum of the proportional term, the integral term and the differential term. Optionally, the target control signal can be a control signal such as a voltage control signal or a current control signal, and the type of target control signal can be set according to the actual application scenario, which is not limited in the embodiments of the present application.

[0062] In the embodiments of the present application, based on the speed deviation between the actual speed and the expected speed, the PID control algorithm is used to calculate the control signal that reduces the speed deviation, that is, the control signal that can increase the speed output by the in-wheel motor and make the speed deviation between the actual speed of the driving wheel and the expected speed tend to 0, to obtain the target control signal. Then, the target control signal can be used to better adjust the speed output by the in-wheel motor. Moreover, the PID algorithm can provide stable control effect by adjusting each control amount, so that when the in-wheel motor is controlled by using the target control signal, there is a certain adaptability and robustness to external disturbances, which can improve the effect of speed control.

[0063] In some embodiments, before step S102, the method further comprises:

[0064] The non-driving wheel resistance is determined based on the load of the non-driving wheel and the road surface friction coefficient.

[0065] The driving wheel adhesion is determined based on the load of the driving wheel, the road surface friction coefficient, and the non-driving wheel resistance.

[0066] The torque threshold is determined according to the driving wheel adhesion and the chain transmission ratio.

[0067] The road surface friction coefficient can reflect the road condition of the current road on which the power-assisted bicycle is located. Alternatively, the road surface friction coefficient can be determined according to user input road condition information, can be determined by a vibration sensor of the power-assisted bicycle, or can be obtained by a navigation system, and the application embodiments do not make specific limitations on the obtaining method of the road surface friction coefficient.

[0068] Since the adhesion between the tire of the power-assisted bicycle and the ground is the key to preventing and controlling the skidding of the power-assisted bicycle, in the application embodiments, the torque threshold can be determined according to the adhesion between the power-assisted bicycle and the ground and the chain transmission ratio of the power-assisted bicycle. Since the driving wheel is the direct source of power of the power-assisted bicycle and directly affects the probability of skidding of the power-assisted bicycle, the torque threshold can be determined according to the adhesion of the driving wheel when determining the torque threshold, so as to further ensure that the actual output torque of the power-assisted bicycle is less than or equal to the torque threshold, and the power-assisted bicycle will not skid, that is, the accuracy and reliability of the torque threshold are improved.

[0069] Due to the structure of the electric bicycle, the loads of the driving wheel and the non-driving wheel have a great influence on the adhesion provided by the driving wheel, and therefore, in the application embodiments, the resistance generated by the non-driving wheel can be determined according to the load of the non-driving wheel and the road surface friction coefficient to obtain the non-driving wheel resistance, then the adhesion that can be provided by the driving wheel is calculated according to the load of the driving wheel, the road surface adhesion coefficient, and the non-driving wheel resistance to obtain the driving wheel adhesion, and finally the torque threshold is calculated according to the driving wheel adhesion and the chain transmission ratio.

[0070] In some embodiments, since the power-assisted bicycle can be in an uphill state, the slope of the road surface also has a certain influence on the adhesion of the driving wheel, and therefore, in order to further improve the accuracy of the adhesion of the driving wheel, the adhesion of the driving wheel can be calculated in combination with the road surface slope, the load of the driving wheel, the road surface friction coefficient, and the non-driving wheel resistance. Alternatively, in order to guarantee the accuracy of the adhesion of the driving wheel while reducing the calculation complexity, the adhesion of the driving wheel can be directly calculated when the road surface slope is less than a slope threshold (such as 10 degrees), and the adhesion of the driving wheel can be calculated in combination with the road surface slope when the road surface slope is greater than or equal to the slope threshold.

[0071] In some embodiments, the driving wheel adhesion force can be expressed as follows:

[0072]

[0073] F_ad is the driving wheel adhesion force, L1 is the load of the driving wheel, L2 is the whole load of the power-assisted bicycle, g is the acceleration of gravity, μ is the road friction coefficient, F_fric is the non-driving wheel resistance, θ is the road slope, and a is the slope threshold.

[0074] Optionally, the road slope described above can be obtained by a navigation system or user input, etc. In some embodiments, the road slope can be determined according to the load of the front wheel and the load of the rear wheel of the power-assisted bicycle. For example, the load of the front wheel and the load of the rear wheel are determined first, and then the load distribution ratio is calculated according to the load of the front wheel and the load of the rear wheel, which is the percentage of the weight of the front wheel to the weight of the rear wheel. After the load distribution ratio is calculated, the road slope can be obtained based on the slope function and the load distribution ratio and the flat load distribution ratio (i.e. the load distribution ratio of the power-assisted bicycle on the ground with a slope of 0, such as 0.85).

[0075] Optionally, the road slope described above can be expressed as follows:

[0076] θ = f(x) = k1*(x) 2 +k2*cos(x-b)+k3*(x-b)+k4

[0077] wherein x is the load distribution ratio, b is the flat load distribution ratio, f(x) is the slope function of the ground slope with respect to the load distribution ratio, b is the flat load distribution ratio, k1, k2, k3 and k4 are all constants, k2, k3 and k4 can be the same value or different values from each other, and k2, k3 and k4 are all less than k1.

[0078] In the embodiments of the present application, since the driving wheel is the direct source of power of the power-assisted bicycle, the torque transmitted to the driving wheel by the motor directly affects the probability of slipping of the power-assisted bicycle, therefore, the torque that the driving wheel should have can be analyzed well through the adhesion force of the driving wheel, so as to determine the motor torque threshold according to the torque. By determining the torque threshold through the above steps, it can be ensured that the power-assisted bicycle will not slip when the actual output torque of the power-assisted bicycle is less than or equal to the torque threshold, i.e. the accuracy and reliability of the torque threshold are improved.

[0079] In some embodiments, the determination of the torque threshold according to the driving wheel adhesion force described above comprises:

[0080] determining the adhesion torque according to the driving wheel adhesion force and the radius of the driving wheel.

[0081] The torque threshold is determined according to the attachment torque and the chain transmission ratio.

[0082] In the process of determining the torque threshold based on the attachment force of the driving wheel, the torque matched with the attachment force of the driving wheel can be calculated according to the attachment force of the driving wheel and the radius of the driving wheel, to obtain an attachment torque. Then, the maximum torque that the motor can output is calculated according to the attachment torque and the chain transmission ratio. The maximum torque is the maximum torque that the motor can output without slipping. That is, when the torque output by the motor is the maximum torque, the torque transmitted to the driving wheel through the chain is exactly equal to the attachment torque corresponding to the attachment force of the driving wheel.

[0083] Further, the torque threshold less than or equal to the maximum torque is determined according to the maximum torque. When the actual output torque of the motor is less than or equal to the torque threshold, the electric bicycle will not slip.

[0084] In some embodiments, the torque threshold can be expressed in the following form:

[0085] M_threshold = F_ad * R_ack * i_chain * c

[0086] Wherein, M_threshold is the torque threshold, F_ad is the attachment force of the driving wheel, R_ack is the radius of the driving wheel, i_chain is the chain transmission ratio, and c is a correction coefficient, whose value range is (0, 1]. In some embodiments, the value range of the correction coefficient can be [0.85, 0.95].

[0087] In some embodiments, the chain transmission ratio can be determined according to the following steps:

[0088] The motor output speed and the driving wheel speed of the electric bicycle in a third preset time period (such as 30 seconds) are obtained, and then the motor output speed and the driving wheel speed are sampled based on a preset time interval (such as 0.5 seconds) to obtain the instantaneous output speed and the instantaneous driving wheel speed corresponding to each sampling time.

[0089] For each sampling time, the reference chain transmission ratio corresponding to the sampling time is calculated according to the instantaneous output speed and the instantaneous driving wheel speed corresponding to the sampling time. After obtaining the reference chain transmission ratio corresponding to each sampling time, it is determined whether there are N (such as 3) continuous same reference chain transmission ratios based on the order of the sampling times.

[0090] If there are N continuous same reference chain transmission ratios, the reference chain transmission ratio can be taken as the actual chain transmission ratio, and the calculation of the torque threshold is based on the chain transmission ratio.

[0091] In the embodiments of the present application, the size of the torque corresponding to the adhesion force of the drive wheel is calculated according to the adhesion force and the radius of the drive wheel, the adhesion torque is obtained, and the maximum torque corresponding to the adhesion torque is inversely deduced in combination with the transmission ratio (i.e., the chain transmission ratio) of the torque output by the output shaft of the middle motor to the drive wheel. Then, the torque threshold can be better determined according to the maximum torque, thereby ensuring the accuracy and reliability of the obtained torque threshold.

[0092] In some embodiments, before determining the non-drive wheel resistance based on the load of the non-drive wheel and the road surface friction coefficient, the method further comprises:

[0093] The drive wheel torque is determined according to the preset friction coefficient, the load of the drive wheel, and the radius of the drive wheel.

[0094] The theoretical output torque is determined according to the drive wheel torque.

[0095] The first rotation speed and the second rotation speed are determined, the first rotation speed and the second rotation speed respectively correspond to the actual rotation speed of the drive wheel and the actual rotation speed of the non-drive wheel when the output torque of the middle motor is the theoretical output torque.

[0096] When the first rotation speed is the same as the second rotation speed, the preset friction coefficient is updated to obtain an updated preset friction coefficient.

[0097] Based on the updated preset friction coefficient, the steps of determining the drive wheel torque and determining the first rotation speed and the second rotation speed are returned until the latest first rotation speed and the latest second rotation speed are different.

[0098] The road surface friction coefficient is determined according to the latest preset friction coefficient.

[0099] In some embodiments, the preset friction coefficient can be determined according to the friction coefficient in the preset friction coefficient interval. For example, assuming that the preset friction coefficient interval is [m, n], where m is less than n, at this time, n can be used as the preset friction coefficient.

[0100] Since the rotation speeds of the drive wheel and the non-drive wheel of the assist bicycle are usually different when slipping occurs, in the process of determining the road surface friction coefficient, the drive torque of the drive wheel under the current load can be calculated according to the preset friction coefficient, the torque that the motor should output is inversely deduced according to the drive torque and the chain transmission ratio, and the theoretical output torque is obtained.

[0101] After obtaining the theoretical output torque, the actual speed of the drive wheel when the motor outputs the theoretical output torque is calculated to obtain the first speed, and the actual speed of the non-drive wheel when the motor outputs the theoretical output torque is calculated to obtain the second speed. Then, it is determined whether the first speed and the second speed are the same. If they are determined to be the same, the preset friction coefficient can be updated by combining the preset friction coefficient difference (such as 0.01) to obtain the updated preset friction coefficient.

[0102] For example, assuming the preset friction coefficient is 0.8 and the preset friction coefficient difference is 0.02; assuming it is determined that the first rotational speed and the second rotational speed are the same, the preset friction coefficient needs to be updated according to the preset friction coefficient difference. At this time, the updated preset friction coefficient is 0.78 (calculated from 0.8-0.02).

[0103] like Figure 2 As shown, after obtaining the updated preset friction coefficient, the process returns to the steps of determining the drive wheel torque and then determining the first and second rotational speeds based on this updated preset friction coefficient. Then, the latest first and second rotational speeds are compared. If the latest determined first and second rotational speeds are the same, the process continues to return to the steps of determining the drive wheel torque and then determining the first and second rotational speeds, until the latest first and second rotational speeds are different.

[0104] When it is determined that the latest first speed and the second speed are different, the actual road surface friction coefficient can be determined based on the latest preset friction coefficient.

[0105] Optionally, if it is initially determined that the latest first speed and second speed are different, the currently updated preset friction coefficient (target preset friction coefficient) can be updated again, and then the process can return to the step of determining the drive wheel torque to determining the first speed and second speed. If this step still determines that the latest first speed and second speed are different, the road surface friction coefficient can be determined based on the target preset friction coefficient. Otherwise, the process can return to the step of determining the drive wheel torque to determining the first speed and second speed, and then judging the latest first speed and second speed.

[0106] In the embodiments of the present application, based on the load of the driving wheel, the preset friction coefficient is set to calculate the driving torque corresponding to the load, and the theoretical output torque corresponding to the driving torque, and then the actual speeds of the driving wheel and the non-driving wheel under the output of the theoretical output torque are combined to determine whether the power-assisted bicycle will slip currently. Since the actual speed of the driving wheel and the actual speed of the non-driving wheel are the same, the power-assisted bicycle usually does not slip, and therefore, the preset friction coefficient can be updated at this time, and the updated preset friction coefficient is used for further analysis until the latest actual speed of the driving wheel and the actual speed of the non-driving wheel are different. The latest preset friction coefficient is taken as the final road surface friction coefficient, that is, the friction coefficient under which the power-assisted bicycle is most likely to slip is found as the actual road surface friction coefficient, so as to calculate the torque threshold, and further improve the reliability of the torque threshold.

[0107] In some embodiments, after the above step S102, the method further comprises:

[0108] In the case where the actual output torque is less than the torque threshold, the second torque control is performed on the middle motor, and the second torque control is used to increase the torque output by the middle motor.

[0109] Since sufficient torque can ensure that the power-assisted bicycle maintains good traction on bad road conditions such as wet ground, reduces the risk of slipping, and improves driving stability, in order to ensure the user's driving experience, if the actual output torque is less than the torque threshold, the second torque control can be performed on the middle motor according to the torque deviation between the actual output torque and the torque threshold, so as to increase the torque output by the middle motor, so that the torque output by the motor is as close as possible to the torque threshold, and the probability of slipping is smaller.

[0110] The torque deviation can be the difference between the actual output torque and the torque threshold.

[0111] It can be understood that after the first torque control or the second torque control is performed on the middle motor, the latest output torque of the middle motor can be obtained, and then whether the power-assisted bicycle will slip currently is determined according to whether the latest actual output torque is greater than the torque threshold, that is, whether the power-assisted bicycle will still slip is determined according to the torque deviation between the latest actual output torque and the torque threshold.

[0112] If the torque deviation is greater than 0, it indicates that the latest actual output torque is greater than the torque threshold, and the power-assisted bicycle will slip. At this time, the first torque control can be performed on the motor according to the torque deviation, that is, the torque output by the motor is reduced, so that the latest actual output torque of the motor is less than or equal to the torque threshold, thereby effectively controlling the slipping phenomenon of the power-assisted bicycle.

[0113] If the torque deviation is less than 0, it indicates that the latest actual output torque is less than the torque threshold, at this time, the output torque of the motor can not be controlled, or the motor can be controlled according to the torque deviation, that is, the output torque of the motor is increased to reduce the torque deviation, and the latest actual output torque is increased to the torque threshold as much as possible to improve the acceleration performance of the power-assisted bicycle and improve the riding stability of the power-assisted bicycle.

[0114] In the embodiments of the present application, when the actual output torque is not equal to the torque threshold, whether the power-assisted bicycle slips or not, the motor of the power-assisted bicycle is controlled according to the size relationship between the actual output torque and the torque threshold first, through the torque control, the output torque of the motor is adjusted to fit the torque threshold as much as possible to reduce the probability of slipping of the power-assisted bicycle, or to improve the acceleration performance of the power-assisted bicycle as much as possible under the condition that the power-assisted bicycle does not slip, thereby improving the riding experience of the user.

[0115] It should be noted that the embodiments of the present application take the control of the torque and speed of the output of the middle motor as an example for description, and in other embodiments, when the torque and speed of the output of the motor in the middle motor are controlled, the transmission ratio of the transmission components in the middle motor (such as the gear transmission ratio in the motor) needs to be combined to calculate the torque threshold and other related data.

[0116] It should be understood that the size of the serial number of each step in the above embodiments does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0117] Embodiment two:

[0118] According to the power-assisted bicycle anti-slip control method described in the above embodiments, Figure 3 The structure block diagram of the power-assisted bicycle anti-slip control device provided by the embodiments of the present application is shown, and only the parts related to the embodiments of the present application are shown for ease of description.

[0119] Referring to Figure 3 The device comprises an actual output torque determination module 31, a judgment module 32 and a first torque control module 33. Among them,

[0120] The actual output torque determination module 31 is used to acquire the actual output torque of the middle motor when the power-assisted bicycle is in the cart mode.

[0121] A judgment module 32 is configured to judge whether the actual output torque is greater than a torque threshold, the torque threshold being calculated in real time according to the chain transmission ratio of the power-assisted bicycle and the adhesion between the power-assisted bicycle and the road surface, and reflecting the maximum torque that the central motor can output in the case that the power-assisted bicycle does not slip.

[0122] A first torque control module 33 is configured to perform first torque control on the central motor when it is determined that the actual output torque is greater than the torque threshold, and the torque output by the central motor in real time after the first torque control is less than or equal to the torque threshold.

[0123] In the embodiments of the present application, after the actual output torque of the central motor of the power-assisted bicycle is obtained, it is first judged whether the actual output torque is greater than the current torque threshold, and first torque control is performed on the motor when it is judged that the actual output torque is greater than the torque threshold. Since the torque threshold is calculated in real time according to the chain transmission ratio of the power-assisted bicycle and the adhesion, it can reflect the maximum torque that the central motor can output in the case that the power-assisted bicycle does not slip, that is, when the actual output torque of the central motor of the power-assisted bicycle is less than or equal to the torque threshold, the power-assisted bicycle will not slip, and when the actual output torque is greater than the torque threshold, the power-assisted bicycle will generally slip, therefore, when it is judged that the actual output torque is greater than the torque threshold, that is, the probability of the power-assisted bicycle slipping is relatively high, the torque output by the central motor of the power-assisted bicycle can be directly adjusted to a value of the torque threshold or below through the first torque control, so that the phenomenon of the power-assisted bicycle slipping can be quickly and effectively controlled. In the control process, the speed of the power-assisted bicycle does not need to be reduced and braking is not required, and the difficulty of pushing the bicycle by the user can be reduced, effectively ensuring the user's riding experience and traffic safety.

[0124] In some embodiments, the power-assisted bicycle anti-slip control device further comprises:

[0125] An actual speed determination module is configured to determine the actual speed of the drive wheel of the power-assisted bicycle when the torque output by the central motor in real time is less than or equal to the torque threshold, the actual speed reflecting the current actual speed of the drive wheel.

[0126] A speed control module is configured to perform speed control on the central motor when the actual speed is less than an expected speed, the speed control being configured to increase the speed output by the central motor, and the expected speed being the expected speed of the drive wheel.

[0127] In some embodiments, the power-assisted bicycle anti-slip control device further comprises:

[0128] A target control signal determination module is configured to determine a target control signal according to a speed deviation between the actual speed and the expected speed and a PID control algorithm.

[0129] An adjustment module is configured to adjust the speed of the output of the mid-motor according to the target control signal.

[0130] In some embodiments, the power-assisted bicycle is an electric bicycle, and the power-assisted bicycle anti-slip control device further comprises:

[0131] A non-driving wheel resistance determination module is configured to determine a non-driving wheel resistance based on a load of the non-driving wheel and a road friction coefficient.

[0132] A driving wheel adhesion determination module is configured to determine a driving wheel adhesion based on the load of the driving wheel, the road friction coefficient, and the non-driving wheel resistance.

[0133] A torque threshold determination module is configured to determine the torque threshold according to the driving wheel adhesion and the chain transmission ratio.

[0134] In some embodiments, in a case where the mid-motor is a mid-motor, the power-assisted bicycle anti-slip control device further comprises:

[0135] An adhesion torque determination module is configured to determine an adhesion torque according to the driving wheel adhesion and a radius of the driving wheel.

[0136] A torque threshold calculation module is configured to determine the torque threshold according to the adhesion torque and the chain transmission ratio.

[0137] In some embodiments, the power-assisted bicycle anti-slip control device further comprises:

[0138] A driving wheel torque determination module is configured to determine a driving wheel torque according to a preset friction coefficient, the load of the driving wheel, and the radius of the driving wheel.

[0139] A theoretical output torque determination module is configured to determine a theoretical output torque according to the driving wheel torque.

[0140] A speed acquisition module is configured to determine a first speed and a second speed, the first speed and the second speed respectively corresponding to an actual speed of the driving wheel and an actual speed of the non-driving wheel in a case where the output torque of the mid-motor is the theoretical output torque.

[0141] A friction coefficient updating module is configured to update the preset friction coefficient to obtain an updated preset friction coefficient in a case where the first speed is the same as the second speed.

[0142] The loop module is used to return to the steps of determining the drive wheel torque and determining the first speed and the second speed based on the updated preset friction coefficient, until the latest first speed and the second speed are different.

[0143] The road surface friction coefficient determination module is used to determine the road surface friction coefficient based on the latest preset friction coefficient.

[0144] In some embodiments, after determining whether the actual output torque is greater than the torque threshold, the method further includes:

[0145] The second torque control module is used to perform second torque control on the mid-drive motor when the actual output torque is less than the torque threshold. The second torque control is used to increase the output torque of the mid-drive motor.

[0146] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0147] Example 3:

[0148] Figure 4 This is a schematic diagram of the structure of a power-assisted bicycle provided in one embodiment of this application. Figure 4 As shown, the power-assisted bicycle 4 of this embodiment includes: at least one processor 40 ( Figure 4 The diagram shows only one processor, a memory 41, and a computer program 42 stored in the memory 41 and executable on the at least one processor 40, which, when executing the computer program 42, performs the steps in any of the above method embodiments.

[0149] The electric bicycle 4 can be an electric bicycle, electric motorcycle, or electric-assisted bicycle, etc. This electric bicycle may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will understand that... Figure 4 This is merely an example of the power-assisted bicycle 4 and does not constitute a limitation on the power-assisted bicycle 4. It may include more or fewer components than shown in the figure, or combine certain components, or different components, such as input / output devices, network access devices, etc.

[0150] The processor 40 can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0151] The memory 41 can be an internal storage unit of the power-assisted bicycle 4, such as a hard disk or a memory provided in the power-assisted bicycle 4 in some embodiments. The memory 41 can also be an external storage device of the power-assisted bicycle 4, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. provided on the power-assisted bicycle 4 in other embodiments. Further, the memory 41 can include both the internal storage unit and the external storage device of the power-assisted bicycle 4. The memory 41 is used to store an operating system, an application program, a boot loader, data, and other programs, such as program codes of the computer program, etc. The memory 41 can also be used to temporarily store data that has been output or will be output.

[0152] It can be clearly understood by those skilled in the art that, for the convenience and brevity of description, only the division of the above functional units and modules is taken as an example for illustration, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to complete all or part of the above-described functions. Each functional unit and module in the embodiments can be integrated in one processing unit, or each unit can exist physically independently, or two or more units can be integrated in one unit, and the integrated unit can be realized in the form of hardware or in the form of a software functional unit. In addition, the specific names of the functional units and modules are only for the purpose of mutual distinction, and do not limit the protection scope of the present application. The specific working process of the units and modules in the system can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0153] The embodiments of the present application further provide a network device, comprising at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, wherein the processor implements the steps in any of the above method embodiments when executing the computer program.

[0154] The embodiments of the present application further provide a computer readable storage medium, which stores a computer program, wherein the computer program is executable by a processor to implement the steps in any of the above method embodiments.

[0155] The embodiments of the present application provide a computer program product, which, when executed on the power-assisted bicycle, enables the power-assisted bicycle to implement the steps in any of the above method embodiments.

[0156] The integrated unit, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the present application implements all or part of the processes in the above embodiments, which can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer readable storage medium, and the computer program, when executed by a processor, can implement the steps in any of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium at least includes any entity or device capable of carrying the computer program code to the photographing device / power-assisted bicycle, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium. For example, U disk, mobile hard disk, magnetic disk or optical disk, etc. In some jurisdictions, according to legislation and patent practice, the computer readable medium cannot be an electrical carrier signal and a telecommunication signal.

[0157] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0158] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0159] In the embodiments provided in the present application, it should be understood that the disclosed apparatus / network device and method can be implemented by other ways. For example, the apparatus / network device embodiments described above are only schematic, for example, the division of the modules or units is only a logical function division, and there can be another division in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between different parts can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0160] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0161] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method for preventing skidding of a power-assisted bicycle provided with a mid-drive motor, characterized by, The method comprises the following steps: When the power-assisted bicycle is in the stroller mode, the actual output torque of the middle motor is obtained; It is determined whether the actual output torque is greater than a torque threshold, the torque threshold being calculated in real time according to the chain transmission ratio corresponding to the power-assisted bicycle and the adhesion between the power-assisted bicycle and the road surface, reflecting the maximum torque that the middle motor can output without slipping of the power-assisted bicycle; When it is determined that the actual output torque is greater than the torque threshold, the first torque control is performed on the middle motor, and after the first torque control is completed, the torque output by the middle motor in real time is less than or equal to the torque threshold; Before the step of determining whether the actual output torque is greater than the torque threshold, the method further comprises the following steps: The non-driven wheel resistance is determined based on the load of the non-driven wheel and the road surface friction coefficient; The driving wheel adhesion is determined based on the load of the driving wheel, the road surface friction coefficient and the non-driven wheel resistance; The torque threshold is determined according to the driving wheel adhesion and the chain transmission ratio.

2. The assisted bicycle anti-skid control method according to claim 1, wherein After the step of performing the first torque control on the middle motor, the method further comprises the following steps: In the case that the torque output by the middle motor in real time is less than or equal to the torque threshold, the actual speed of the driving wheel of the power-assisted bicycle is determined, the actual speed reflecting the current actual speed reached by the driving wheel; In the case that the actual speed is less than an expected speed, the speed control is performed on the middle motor, the speed control being used to increase the speed output by the middle motor, the expected speed being the expected speed reached by the driving wheel.

3. The antiskid control method of a power-assisted bicycle according to claim 2, wherein The step of performing the speed control on the middle motor comprises the following steps: The target control signal is obtained by calculating according to the speed deviation between the actual speed and the expected speed and a PID control algorithm; The speed output by the middle motor is adjusted by using the target control signal.

4. The antiskid control method of a power-assisted bicycle according to claim 1, characterized in that, The step of determining the torque threshold according to the driving wheel adhesion and the chain transmission ratio comprises the following steps: The adhesion torque is determined according to the driving wheel adhesion and the radius of the driving wheel; The torque threshold is determined according to the adhesion torque and the chain transmission ratio.

5. The antiskid control method of a power-assisted bicycle according to claim 1, wherein, Before the step of determining the non-driven wheel resistance based on the load of the non-driven wheel and the road surface friction coefficient, the method further comprises the following steps: The driving wheel torque is determined according to a preset friction coefficient, the load of the driving wheel and the radius of the driving wheel; The theoretical output torque is determined according to the driving wheel torque; The first speed and the second speed are determined, the first speed and the second speed respectively corresponding to the actual speed of the driving wheel and the actual speed of the non-driven wheel in the case that the output torque of the middle motor is the theoretical output torque; In the case that the first speed is the same as the second speed, the preset friction coefficient is updated to obtain an updated preset friction coefficient; Based on the updated preset friction coefficient, the steps of determining the driving wheel torque and determining the first speed and the second speed are returned until the latest first speed and the latest second speed are different; The road surface friction coefficient is determined according to the latest preset friction coefficient.

6. The antiskid control method for a power-assisted bicycle according to any one of claims 1 to 5, characterized in that, After the judging whether the actual output torque is greater than a torque threshold, further comprising: In a case that the actual output torque is less than the torque threshold, performing a second torque control on the middle motor, the second torque control being used to increase the torque output by the middle motor.

7. An anti-skid control device for a power-assisted bicycle, characterized by The power-assisted bicycle is provided with a middle motor, comprising: An actual output torque determination module, configured to acquire an actual output torque of the middle motor when the power-assisted bicycle is in a cart mode; A judging module, configured to judge whether the actual output torque is greater than a torque threshold, the torque threshold being calculated in real time according to a chain transmission ratio corresponding to the power-assisted bicycle and adhesion between the power-assisted bicycle and a road surface, and reflecting a maximum torque outputtable by the middle motor in a case that the power-assisted bicycle does not slip; A first torque control module, configured to perform a first torque control on the middle motor when it is determined that the actual output torque is greater than the torque threshold, the torque output in real time by the middle motor being less than or equal to the torque threshold after the first torque control ends; The power-assisted bicycle anti-slip control device further comprises: The power-assisted bicycle anti-slip control device further comprises: A non-driving wheel resistance determination module, configured to determine a non-driving wheel resistance based on a load of a non-driving wheel and a road surface friction coefficient; A driving wheel adhesion determination module, configured to determine a driving wheel adhesion based on a load of a driving wheel, the road surface friction coefficient and the non-driving wheel resistance; A torque threshold determination module, configured to determine the torque threshold according to the driving wheel adhesion and the chain transmission ratio.

8. An assisted bicycle comprising a memory, a processor and a computer program stored in the memory and loadable into the processor, characterized in that, The computer program is executed by the processor to implement the method of any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 8. The computer program is executed by the processor to implement the method of any one of claims 1 to 6.

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