WO2023231128A1

WO2023231128A1 - Speed control method and device for use in electric bicycle pushing mode

Info

Publication number: WO2023231128A1
Application number: PCT/CN2022/102730
Authority: WO
Inventors: 陈衍钦
Original assignee: 广东高标智能科技股份有限公司
Priority date: 2022-06-02
Filing date: 2022-06-30
Publication date: 2023-12-07
Also published as: CN114834585A; CN114834585B; DE112022002517T5

Abstract

Embodiments of the present application disclose a speed control method and device for use in an electric bicycle pushing mode. The speed control method for use in an electric bicycle pushing mode comprises: determining a rotating speed estimate value of a mid-drive motor and a rotating speed compensation value of the mid-drive motor according to a target mechanical gear and a rear wheel speed; determining a rotating speed target value of the mid-drive motor according to the rotating speed estimate value and the rotating speed compensation value; determining a motor target driving torque value of the mid-drive motor according to the rotating speed target value and an actual rotating speed of the mid-drive motor; and gradually adjusting the motor driving torque value of the mid-drive motor to the motor target driving torque value within a preset time period.

Description

Electric vehicle push mode vehicle speed control method and device

This application claims priority to the Chinese patent application with application number 202210625647.8, which was submitted to the China Patent Office on June 2, 2022. The entire content of this application is incorporated into this application by reference.

Technical field

The embodiments of the present application relate to the technical field of electric vehicle control, and in particular, to a method and device for controlling the speed of an electric vehicle in push cart mode.

Background technique

As the global greenhouse effect gradually intensifies, people's demands for environmental protection become stronger and stronger. Among them, exhaust emissions from fuel vehicles are an important reason for the global greenhouse effect. In response to the concept of green environmental protection, electric bicycles are becoming more and more popular with their environmental protection and energy-saving advantages. Favored by people.

The stroller walking mode is one of the important functions of electric bicycles. In the stroller walking mode, the electric bicycle needs to provide the user with auxiliary driving force so that the user can more easily follow the car and walk. Therefore, the speed of the electric bicycle needs to be maintained at 6km/h in the stroller walking mode.

In order to reduce the cost and manufacturing structural complexity of electric bicycles, electric bicycles mainly use low-precision wheel speed sensors to detect vehicle speed in real time, thereby achieving low speed control of electric bicycles. However, the use of low-precision wheel speed sensors to control the low speed of electric bicycles has the problem of slow response speed, which will cause the constant speed control of electric bicycles to lag and the speed limit of electric bicycles to lag behind, which will cause huge safety risks. In addition, the traditional constant speed control of the electric bicycle cart mode has the problem of poor user experience. In order to make the vehicle speed reach the target speed, the traditional speed closed-loop control easily makes people feel like being dragged by the vehicle.

Contents of the invention

Embodiments of the present application provide a method and device for controlling the speed of an electric vehicle in push-cart mode, which improves the control accuracy of low vehicle speeds and improves the comfort of user experience on the premise of using a low-precision wheel speed sensor.

In the first aspect, embodiments of the present application provide a method for controlling the speed of an electric vehicle in push cart mode, which includes:

Based on the target mechanical gear and rear wheel speed, determine the estimated speed of the mid-mounted motor and the speed compensation value of the mid-mounted motor;

According to the estimated speed value and the speed compensation value, determine the speed target value of the mid-mounted motor;

According to the target speed value and the actual speed of the mid-mounted motor, determine the motor target driving torque value of the mid-mounted motor;

Within the preset time, the motor driving torque value of the mid-mounted motor is gradually adjusted to the motor target driving torque value.

Optionally, the method for determining the estimated speed of the mid-mounted motor includes:

According to the target mechanical gear, obtain the target sprocket ratio of the mid-mounted motor;

The rpm estimate is determined based on the rear wheel speed, target sprocket ratio, and mid-motor gear ratio.

Optionally, after determining the target speed value of the mid-mounted motor and before determining the target driving torque value of the mid-mounted motor, the method also includes:

Determine the speed range of the mid-mounted motor based on the target vehicle speed, maximum mechanical gear, minimum mechanical gear, and the transmission ratio of the mid-mounted motor;

Determine whether the speed target value is within the speed range;

If not, reset the speed target value according to the speed range.

Optionally, methods for determining the speed range of the mid-mounted motor include:

Get the first sprocket ratio based on the maximum mechanical gear;

According to the target vehicle speed, transmission ratio and first sprocket ratio, determine the maximum speed value of the mid-mounted motor speed;

Obtain the second sprocket ratio based on the minimum mechanical gear;

According to the target vehicle speed, transmission ratio and second sprocket ratio, determine the minimum speed value of the mid-mounted motor speed.

Optionally, the method for determining the motor target driving torque value of the mid-mounted motor includes:

Get the actual speed of the mid-mounted motor;

According to the target speed value and the actual speed of the mid-mounted motor, the target difference value is obtained;

According to the target difference value, determine the target driving torque value of the motor.

Optionally, methods for obtaining the actual speed of the mid-mounted motor include:

Obtain the mechanical angle of the mid-mounted motor in the current sampling cycle, the mechanical angle of the mid-mounted motor in the previous sampling cycle, and the sampling frequency of the mid-mounted motor's mechanical angle;

The actual rotation speed of the mid-mounted motor is calculated based on the mechanical angle of the mid-mounted motor in the current sampling period, the mechanical angle of the mid-mounted motor in the previous sampling cycle, and the sampling frequency of the mechanical angle of the mid-mounted motor.

Optionally, the method of gradually adjusting the motor driving torque value of the mid-mounted motor to the motor target driving torque value includes:

According to the rear wheel speed, obtain the maximum driving torque value of the motor;

In the process of gradually adjusting the motor driving torque value to the motor target driving torque value, it is judged in real time whether the motor driving torque value after each adjustment is greater than the motor's maximum driving torque value;

If yes, the maximum driving torque value is output;

Otherwise, output the motor drive torque value.

Optionally, the motor driving torque value changes linearly within a preset time until it is equal to the motor target driving torque value.

Optionally, methods for obtaining the maximum driving torque value of the motor include:

Obtain the relationship curve between the rear wheel speed and the maximum driving torque value of the motor;

According to the relationship curve between the rear wheel speed and the maximum driving torque value of the motor and the rear wheel speed, the maximum driving torque value of the motor is obtained.

In a second aspect, embodiments of the present application also provide a vehicle speed control device in push-cart mode for an electric vehicle, which includes:

The first determination module is used to determine the speed estimate of the mid-mounted motor and the speed compensation value of the mid-mounted motor based on the target mechanical gear and the rear wheel speed;

The second determination module is used to determine the target speed value of the mid-mounted motor based on the estimated speed value and the speed compensation value;

The third determination module is used to determine the motor target driving torque value of the mid-mounted motor based on the target speed value and the actual speed of the mid-mounted motor;

The adjustment module is used to gradually adjust the motor drive torque value of the mid-mounted motor to the indicated motor target drive torque value within a preset time.

The embodiment of the present application determines the estimated rotation speed of the mid-mounted motor and the rotation speed compensation value of the mid-mounted motor based on the target mechanical gear and the rear wheel speed, which can facilitate subsequent adjustments based on the estimated rotation speed of the mid-mounted motor. According to the estimated speed value and the speed compensation value, the speed target value of the mid-mounted motor is determined, and the target speed value of the mid-mounted motor can be obtained indirectly without knowing the sprocket ratio. According to the speed target value and the actual speed of the mid-mounted motor, the motor target driving torque value of the mid-mounted motor is determined. Within the preset time, the motor driving torque value of the mid-mounted motor is gradually adjusted to the motor target driving torque value, so that the user will not have an obvious pulling feeling in the stroller mode, thereby improving the comfort of the user experience. In summary, this solution can convert the adjustment of the vehicle speed into the adjustment of the speed target value of the mid-mounted motor, thus improving the control accuracy at low vehicle speeds.

Description of the drawings

Figure 1 is a schematic flowchart of a method for controlling the speed of an electric vehicle in push cart mode provided by an embodiment of the present application;

Figure 2 is a relationship graph between rear wheel speed and rotational speed compensation value provided by an embodiment of the present application;

Figure 3 is a schematic flowchart of a method for determining an estimated rotation speed of a mid-mounted motor provided by an embodiment of the present application;

Figure 4 is a schematic flowchart of a method for determining the rotation speed target value of the mid-mounted motor provided by an embodiment of the present application;

Figure 5 is a schematic flowchart of another vehicle speed control method in the push cart mode of an electric vehicle provided by an embodiment of the present application;

Figure 6 is a schematic flowchart of a method for determining the rotation speed range of a mid-mounted motor provided by an embodiment of the present application;

Figure 7 is a schematic flowchart of a method for determining the motor target driving torque value of a mid-mounted motor provided by an embodiment of the present application;

Figure 8 is a schematic flow chart of a method for obtaining the actual rotation speed of a mid-mounted motor provided by an embodiment of the present application;

Figure 9 is a schematic flowchart of a method for gradually adjusting the motor driving torque value of a mid-mounted motor to the motor target driving torque value according to an embodiment of the present application;

Figure 10 is a schematic flow chart of a method for obtaining the maximum driving torque value of a motor provided by an embodiment of the present application;

Figure 11 is a relationship graph between the rear wheel speed and the maximum driving torque value of the motor provided by the embodiment of the present application;

Figure 12 is a schematic structural diagram of a loop control circuit provided by an embodiment of the present application;

Figure 13 is a schematic diagram showing the results of an electric vehicle push mode speed control device provided by an embodiment of the present application.

Detailed ways

In order to enable those in the technical field to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only These are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the scope of protection of this application.

It should be noted that the terms "target", "first", "second", etc. in the description and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific sequence. Or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances so that the embodiments of the application described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the term "comprises" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or apparatus that includes a series of steps or units need not be limited to those steps or units expressly listed. , but may include other steps or elements not expressly listed or inherent to such processes, methods, products or devices.

Figure 1 is a schematic flowchart of a method for controlling the speed of an electric bicycle in the push cart mode provided by an embodiment of the present application. This embodiment can be applied to low-speed control in the electric bicycle push mode. This method can be controlled by the speed of an electric bicycle in the push cart mode. The device can be implemented by hardware and/or software. The method specifically includes the following steps:

S110. Determine the estimated speed value of the mid-mounted motor and the speed compensation value of the mid-mounted motor based on the target mechanical gear and the rear wheel speed.

Specifically, the mid-mounted motor refers to the drive motor installed in the middle position (pedal position) of the electric bicycle body. The mid-mounted motor is connected to the body of the electric bicycle and connected to the rear wheel through multiple chains to realize power transmission from the drive motor to the rear wheel. Among them, the mid-mounted motor includes multiple mechanical gears. Each different mechanical gear corresponds to a different chain connected to the rear wheel. You can choose any mechanical gear as the target mechanical gear. For example, the middle gear of the electric bicycle can be selected as the target mechanical gear. The rear wheel speed can be collected through a low-precision wheel speed sensor. It should be noted that the rear wheel speed collected through a low-precision wheel speed sensor is inaccurate.

Since the current specific gear position and actual vehicle speed of the electric bicycle are not accurate values, the estimated speed of the mid-mounted motor calculated based on the target mechanical gear and the current vehicle speed is not the actual speed of the current mid-mounted motor, but an estimate of the mid-mounted motor speed. An estimated value of the motor speed, which facilitates subsequent adjustments based on the estimated speed of the mid-mounted motor.

The speed compensation value of the mid-mounted motor can be obtained by looking up the relationship between the rear wheel speed and the speed compensation value based on the rear wheel speed or the relationship curve between the rear wheel speed and the speed compensation value. Among them, the correspondence table of the relationship between the rear wheel speed and the rotational speed compensation value or the relationship curve between the rear wheel speed and the rotational speed compensation value that is consulted based on the rear wheel speed is preset by the designer. Exemplarily, FIG. 2 is a relationship graph between rear wheel speed and rotational speed compensation value provided by an embodiment of the present application, in which the abscissa is the rear wheel speed and the ordinate is the rotational speed compensation value. Figure 2 includes three curves of the relationship between rear wheel speed and rotational speed compensation value, namely curve 210, curve 220 and curve 230. When curve 210, curve 220 and curve 230 are the corresponding rotational speeds when the rear wheel speed is too large or too small The compensation values are the same. Curve 210, curve 220 and curve 230 are all 0 when the rear wheel speed is 6.

It should be noted that when the designer presets the relationship curve between the rear wheel speed and the rotation speed compensation value, since the rear wheel speed collected by the low-precision wheel speed sensor is in a stepped shape, the relationship curve between the rear wheel speed and the rotation speed compensation value will also be different. It also shows a staircase shape. At this time, it is necessary to design a filter based on the motor speed estimation filter coefficient to make the transition of the relationship curve between the rear wheel speed and the speed compensation value smoother, so that the obtained speed compensation values corresponding to different rear wheel speeds are more stable. , the designed speed compensation value follows the rear wheel speed curve more smoothly.

S120. Determine the target speed value of the mid-mounted motor based on the estimated speed value and the speed compensation value.

Specifically, every time the rear wheel makes one revolution, a rising edge appears in the wheel speed signal. When the rising edge is detected, the rear wheel speed is updated, and then the speed compensation value is obtained through the updated relationship curve between the rear wheel speed and the speed compensation value, and based on The estimated speed value and the estimated speed value determine the target speed value of the mid-mounted motor, that is, the target speed value of the mid-mounted motor is equal to the sum of the estimated speed value and the speed compensation value. Therefore, the above process can indirectly obtain the target speed value of the mid-mounted motor without knowing the sprocket ratio.

It should be noted that since the electric bicycle is driven by the rear wheel, the speed of the rear wheel of the electric bicycle is equal to the speed of the electric bicycle.

S130. Determine the motor target driving torque value of the mid-mounted motor based on the target speed value and the actual speed of the mid-mounted motor.

Among them, the torque output by the motor is related to the speed of the mid-mounted motor. From this, the difference between the target speed value and the actual speed of the mid-mounted motor can be calculated based on the target speed value and the actual speed of the mid-mounted motor. According to the target speed value, The difference between the actual speed of the mid-mounted motor and the actual speed of the mid-mounted motor determines the motor target driving torque value of the mid-mounted motor.

S140. Within the preset time, gradually adjust the motor driving torque value of the mid-mounted motor to the motor target driving torque value.

Specifically, in order to enhance the user's comfort in the stroller mode and avoid the obvious pulling sensation caused by the mid-mounted motor speed following the motor's target driving torque value under the motor speed closed-loop control, the center motor can be gradually adjusted within a preset time. Set the motor drive torque value of the motor to the motor target drive torque value to gradually adjust the speed of the mid-mounted motor, thereby adjusting the rear wheel speed, that is, adjusting the vehicle speed.

The embodiment of the present application determines the estimated rotation speed of the mid-mounted motor and the rotation speed compensation value of the mid-mounted motor based on the target mechanical gear and the rear wheel speed, which can facilitate subsequent adjustments based on the estimated rotation speed of the mid-mounted motor. According to the estimated speed value and the speed compensation value, the speed target value of the mid-mounted motor is determined, and the target speed value of the mid-mounted motor can be obtained indirectly without knowing the sprocket ratio. According to the speed target value and the actual speed of the mid-mounted motor, the motor target driving torque value of the mid-mounted motor is determined. Within the preset time, the motor driving torque value of the mid-mounted motor is gradually adjusted to the motor target driving torque value, so that the user will not have an obvious pulling feeling in the stroller mode, thereby improving the comfort of the user experience. In summary, this solution can convert the adjustment of the vehicle speed into the adjustment of the speed target value of the mid-mounted motor, thereby improving the control accuracy at low vehicle speeds.

Exemplarily, Figure 3 is a schematic flowchart of a method for determining the estimated rotation speed of a mid-mounted motor provided by an embodiment of the present application. Based on the above embodiment, the method for determining the estimated rotation speed of a mid-mounted motor is further performed. Detailed description:

S310. According to the target mechanical gear, obtain the target sprocket ratio of the mid-mounted motor.

Among them, the sprocket ratio is the rotation ratio between the chain and the rear wheel driven by the mid-mounted motor. For example, if the mid-mounted motor drives the chain of the rear wheel to rotate once, and the rear wheel also rotates once, the sprocket ratio at this time is 1:1. Each different mechanical gear of the mid-mounted motor corresponds to a different chain connected to the rear wheel. Therefore, according to the selected target mechanical gear, the chain driven by the mid-mounted motor to rotate with the rear wheel can be determined, thereby determining the target sprocket ratio.

S320: Determine the speed estimate based on the rear wheel speed, the target sprocket ratio and the transmission ratio of the mid-mounted motor.

Specifically, the transmission ratio of the mid-mounted motor refers to the angular velocity ratio between the mechanical gears that mesh with each other inside the motor. Estimated speed = rear wheel speed * target sprocket ratio * transmission ratio of the mid-mounted motor.

In summary, the above method can be used to estimate the rotation speed in advance, so that subsequent adjustments can be made based on the rotation speed estimate of the mid-mounted motor to obtain a rotation speed target value that meets the requirements.

Exemplarily, Figure 4 is a schematic flowchart of a method for determining the target speed value of the mid-mounted motor provided by an embodiment of the present application. Based on the above embodiment, further steps are taken to determine the target speed value of the mid-mounted motor. Detailed description:

S410. Determine whether the rising edge of the wheel speed signal is detected. If yes, execute S420; if not, execute S410 again.

S420. Determine the speed compensation value of the mid-mounted motor based on the rear wheel speed.

S430. Determine the target speed value of the mid-mounted motor based on the estimated speed value and the speed compensation value.

S440: Determine the speed range of the mid-mounted motor based on the target vehicle speed, the maximum mechanical gear, the minimum mechanical gear, and the transmission ratio of the mid-mounted motor.

S450. Determine whether the speed target value is within the speed range. If yes, execute S470; if not, execute S460.

S460. Reset the speed target value according to the speed range.

S470, output speed target value.

In summary, the above scheme determines the speed range of the mid-mounted motor after determining the target speed value of the motor, and can determine whether the estimated speed target value is reasonable, thereby ensuring the rationality of subsequent steps.

Figure 5 is a schematic flowchart of another method for controlling the speed of an electric vehicle in cart mode provided by an embodiment of the present application. The method specifically includes the following steps:

S510. Determine the speed estimate of the mid-mounted motor and the speed compensation value of the mid-mounted motor based on the target mechanical gear and the rear wheel speed.

S520. Determine the target speed value of the mid-mounted motor based on the estimated speed value and the speed compensation value.

S530: Determine the speed range of the mid-mounted motor based on the target vehicle speed, the maximum mechanical gear, the minimum mechanical gear, and the transmission ratio of the mid-mounted motor.

Among them, the target vehicle speed is the speed to which the rear wheel speed needs to be adjusted. Since the maximum mechanical gear, the minimum mechanical gear, and the transmission ratio of the mid-mounted motor of the electric bicycle are all known, the speed range of the mid-mounted motor can be accurately obtained, and the estimate can be confirmed based on the speed range of the mid-mounted motor. Is the speed estimate reasonable?

S540. Determine whether the speed target value is within the speed range.

S550. If not, reset the speed target value according to the speed range.

It should be noted that resetting the speed target value requires a value within the speed range.

S560: Determine the motor target driving torque value of the mid-mounted motor based on the target speed value and the actual speed of the mid-mounted motor.

S570. Within the preset time, gradually adjust the motor driving torque value of the mid-mounted motor to the motor target driving torque value.

In summary, this solution can convert the adjustment of the vehicle speed into the adjustment of the speed target value of the mid-mounted motor, thus improving the control accuracy at low vehicle speeds.

Exemplarily, FIG. 6 is a schematic flowchart of a method for determining the rotation speed range of a mid-mounted motor provided by an embodiment of the present application. Based on the above embodiment, the method for determining the rotation speed range of a mid-mounted motor is further refined. illustrate:

S610, obtain the first sprocket ratio based on the maximum mechanical gear.

S620: Determine the maximum speed value of the mid-mounted motor speed based on the target vehicle speed, transmission ratio and first sprocket ratio.

Among them, the target vehicle speed is the current rear wheel speed that you want to adjust to. The maximum speed value of the mid-mounted motor speed = target vehicle speed * transmission ratio * first sprocket ratio.

S630, obtain the second sprocket ratio based on the minimum mechanical gear.

S640: Determine the minimum speed value of the mid-mounted motor speed based on the target vehicle speed, transmission ratio and second sprocket ratio.

Among them, the minimum speed value of the mid-mounted motor speed = target vehicle speed * transmission ratio * second sprocket ratio.

In summary, the above solution can accurately determine the speed range of the mid-mounted motor, thereby determining whether the estimated speed value is reasonable and ensuring the rationality of subsequent steps.

Exemplarily, FIG. 7 is a schematic flowchart of a method for determining the motor target driving torque value of a mid-mounted motor provided by an embodiment of the present application. Based on the above embodiment, the method is used to determine the motor target driving torque value of a mid-mounted motor. The method is further detailed:

S710. Obtain the actual speed of the mid-mounted motor.

S720: Obtain the target difference based on the target speed value and the actual speed of the mid-mounted motor.

Among them, by making a difference between the speed target value and the actual speed of the mid-mounted motor, the difference between the actual speed of the mid-mounted motor and the desired speed target value can be known, that is, the target difference value. From this, the mid-mounted motor can be clearly known The actual speed needs to be adjusted for the speed difference.

S730. Determine the target driving torque value of the motor according to the target difference value.

Among them, after obtaining the target difference value, the target difference can be converted into a motor driving torque value that needs to be adjusted, so that the current motor driving torque value of the motor can be adjusted to the motor target driving torque value to adjust the actual speed of the mid-mounted motor. to the speed target value of the mid-mounted motor.

To sum up, the above solution exemplarily shows a way to adjust the speed of the mid-mounted motor. Designers can also adjust the speed of the mid-mounted motor through other technical means, and this solution does not impose specific restrictions on this.

Exemplarily, FIG. 8 is a schematic flowchart of a method for obtaining the actual rotation speed of a mid-mounted motor provided by an embodiment of the present application. Based on the above embodiment, the method for obtaining the actual rotation speed of a mid-mounted motor is further refined. illustrate:

S810: Obtain the mechanical angle of the middle motor in the current sampling period, the mechanical angle of the previous sampling period of the middle motor, and the sampling frequency of the mechanical angle of the middle motor.

Specifically, the mechanical angle of the mid-mounted motor in the current sampling cycle and the mechanical angle of the mid-mounted motor in the previous sampling cycle can be detected and obtained through the motor angle detection module. The sampling frequency of the mechanical angle of the mid-mounted motor is the frequency at which the motor angle detection module samples the mechanical angle of the mid-mounted motor in unit time.

S820: Calculate the actual rotation speed of the mid-mounted motor based on the mechanical angle of the mid-mounted motor in the current sampling period, the mechanical angle of the mid-mounted motor in the previous sampling cycle, and the sampling frequency of the mechanical angle of the mid-mounted motor.

For example, if the mechanical angle of the middle motor in the current sampling period is X1, the mechanical angle of the previous sampling period of the middle motor is X2, and the sampling frequency of the mechanical angle of the middle motor is f1, then the actual rotation speed n of the middle motor is :

To sum up, the above solution exemplarily shows a way to calculate the actual speed of the mid-mounted motor. Designers can also obtain the actual speed of the mid-mounted motor through other technical means, and this solution does not impose specific restrictions on this.

Exemplarily, FIG. 9 is a schematic flowchart of a method for gradually adjusting the motor driving torque value of the mid-mounted motor to the motor target driving torque value according to the embodiment of the present application. Based on the above embodiment, the stepwise adjustment of the motor driving torque value of the mid-mounted motor is performed. The method of setting the motor drive torque value of the motor to the motor target drive torque value is further explained in detail:

S910. Obtain the maximum driving torque value of the motor based on the rear wheel speed.

Specifically, the maximum driving torque value of the motor can be obtained by searching the relationship between the rear wheel speed and the maximum driving torque value of the motor or the relationship curve between the rear wheel speed and the maximum driving torque value of the motor according to the rear wheel speed. Among them, the correspondence table of the relationship between the rear wheel speed and the maximum driving torque value of the motor, or the relationship curve between the rear wheel speed and the maximum driving torque value of the motor, which is consulted based on the rear wheel speed, is preset by the designer.

S920. In the process of gradually adjusting the motor driving torque value to the motor target driving torque value, determine in real time whether the motor driving torque value after each adjustment is greater than the motor's maximum driving torque value.

S930. If yes, output the maximum driving torque value.

S940. Otherwise, output the motor driving torque value.

Among them, in the process of gradually adjusting the motor driving torque value to the motor target driving torque value, the motor driving torque value cannot be directly adjusted to the motor target driving torque value to avoid the user having an obvious pulling feeling when pushing the cart. , allowing users to follow the car naturally and comfortably, improving the user's experience and comfort of the stroller.

In summary, the above solution achieves control of the starting strength of the electric self-phase bicycle by controlling the output driving torque value of the electric bicycle.

Optionally, there are many ways to gradually adjust the motor driving torque value to the motor target driving torque value. For example, the motor driving torque value changes linearly within a preset time until it is equal to the motor target driving torque value.

Specifically, the preset motor driving torque value is a function that changes linearly within the preset time. The function is as follows:

in,

is the motor drive torque value, T _ecmd is the motor target drive torque value, K is the step coefficient of the motor drive torque value changing with time, and t is time.

Exemplarily, FIG. 10 is a schematic flowchart of a method for obtaining the maximum driving torque value of a motor provided by an embodiment of the present application. Based on the above embodiment, the method for obtaining the maximum driving torque value of a motor is further refined. illustrate:

S1010. Obtain the relationship curve between the rear wheel speed and the maximum driving torque value of the motor.

For example, FIG. 11 is a relationship graph between the rear wheel speed and the maximum driving torque value of the motor provided by an embodiment of the present application. The abscissa is the rear wheel speed, and the ordinate is the maximum driving torque value of the motor. When the rear wheel speed is 0, the maximum driving torque value of the motor output is 50; when the rear wheel speed is greater than or equal to 6, the maximum driving torque value of the motor output is 0.

S1020. Obtain the maximum driving torque value of the motor according to the relationship curve between the rear wheel speed and the maximum driving torque value of the motor and the rear wheel speed.

It should be noted that when designers pre-set the relationship curve between rear wheel speed and motor maximum driving torque value, they need to consider the process of starting an electric bicycle on a steep slope. Therefore, in order to start on a steep slope, the rear wheel speed designed by the designer When it is lower, the corresponding maximum driving torque value of the motor should not be too small. Therefore, it is necessary to follow the principle that the lower the rear wheel speed is, the greater the maximum allowable torque is, and when the rear wheel speed is close to the target vehicle speed, the maximum allowable torque is smaller.

In summary, the above solution can limit the starting force of the electric bicycle by obtaining the maximum driving torque value of the motor.

Figure 12 is a schematic structural diagram of a loop control circuit provided by an embodiment of the present application. As shown in Figure 12, specifically, the rear wheel speed input correction circuit 001 can output the speed compensation value of the mid-mounted motor. The speed compensation value of the mid-mounted motor and the estimated speed value of the mid-mounted motor are input into the summing circuit 002, which can output the target speed value of the mid-mounted motor. The rotational speed target value of the mid-mounted motor is input to the rotational speed limiter circuit 003, which can determine whether the rotational speed target value of the mid-mounted motor is within the rotational speed range, and output the rotational speed target value of the mid-mounted motor within the rotational speed range. The speed target value of the mid-mounted motor and the actual speed of the mid-mounted motor are input to the difference circuit 004, and the target difference value can be output. The target difference input PI circuit can convert the target difference into the motor target driving torque value and output the motor target driving torque value. The motor target driving torque value input adjustment circuit 006 can gradually adjust the motor driving torque value of the mid-mounted motor to the motor target driving torque value within a preset time. Each time the adjusted output motor driving torque value is input to the torque limiting circuit 007, the final output motor driving torque value can be determined.

Figure 12 is a schematic diagram showing the results of an electric vehicle push-cart mode speed control device provided by an embodiment of the present application. The electric vehicle push-cart mode speed control device includes:

The first determination module 01 is used to determine the estimated speed of the mid-mounted motor and the speed compensation value of the mid-mounted motor based on the target mechanical gear and the rear wheel speed;

The second determination module 02 is used to determine the target speed value of the mid-mounted motor based on the estimated speed value and the speed compensation value;

The third determination module 03 is used to determine the motor target driving torque value of the mid-mounted motor based on the target speed value and the actual speed of the mid-mounted motor;

The adjustment module 04 is used to gradually adjust the motor driving torque value of the mid-mounted motor to the indicated motor target driving torque value within a preset time.

The embodiment of the present application uses the first determination module to determine the estimated rotation speed of the mid-mounted motor and the rotation speed compensation value of the mid-mounted motor based on the target mechanical gear and the rear wheel speed, which can facilitate subsequent calculations based on the estimated rotation speed of the mid-mounted motor. Make adjustments. The second determination module determines the target speed value of the mid-mounted motor based on the estimated speed value and the speed compensation value, and can indirectly obtain the target speed value of the mid-mounted motor without knowing the sprocket ratio. The third determination module determines the motor target driving torque value of the mid-mounted motor based on the target speed value and the actual speed of the mid-mounted motor. The adjustment module gradually adjusts the motor driving torque value of the mid-mounted motor to the motor target driving torque value within a preset time, so that the user will not have an obvious pulling feeling in the cart mode, thereby improving the comfort of the user experience. In summary, this solution can convert the adjustment of the vehicle speed into the adjustment of the speed target value of the mid-mounted motor, thus improving the control accuracy at low vehicle speeds.

Optionally, the first determination module includes:

The target sprocket ratio acquisition unit is used to acquire the target sprocket ratio of the mid-mounted motor according to the target mechanical gear;

The rotation speed estimation value determination unit is used to determine the rotation speed estimation value based on the rear wheel speed, the target sprocket ratio and the transmission ratio of the mid-mounted motor.

Optionally, the electric vehicle push mode speed control device also includes: a judgment module, which includes:

A speed range determination unit used to determine the speed range of the mid-mounted motor based on the target vehicle speed, the maximum mechanical gear, the minimum mechanical gear, and the transmission ratio of the mid-mounted motor;

The first judgment unit is used to judge whether the speed target value is within the speed range;

The setting unit is used to reset the speed target value according to the speed range if the speed target value is not within the speed range.

Optionally, the rotation speed range determination unit includes:

The first acquisition subunit is used to acquire the first sprocket ratio according to the maximum mechanical gear;

The maximum speed value determination subunit is used to determine the maximum speed value of the mid-mounted motor speed based on the target vehicle speed, transmission ratio and first sprocket ratio;

The second acquisition subunit is used to acquire the second sprocket ratio according to the minimum mechanical gear;

The minimum speed value determination subunit is used to determine the minimum speed value of the mid-mounted motor speed based on the target vehicle speed, transmission ratio and second sprocket ratio.

Optionally, the third determination module includes:

The actual speed acquisition unit is used to obtain the actual speed of the mid-mounted motor;

The target difference obtaining unit is used to obtain the target difference based on the speed target value and the actual speed of the mid-mounted motor;

The motor target driving torque value determination unit is used to determine the motor target driving torque value according to the target difference value.

Optionally, the actual speed acquisition unit includes:

The parameter acquisition subunit is used to obtain the mechanical angle of the mid-mounted motor in the current sampling cycle, the mechanical angle of the mid-mounted motor in the previous sampling cycle, and the sampling frequency of the mid-mounted motor mechanical angle;

The actual speed calculation subunit of the mid-mounted motor is used to calculate the actual speed of the mid-mounted motor based on the mechanical angle of the mid-mounted motor in the current sampling period, the mechanical angle of the mid-mounted motor in the previous sampling cycle, and the sampling frequency of the mechanical angle of the mid-mounted motor.

Optionally, the adjustment module includes:

The motor's maximum driving torque value acquisition unit is used to obtain the motor's maximum driving torque value based on the rear wheel speed;

The second judgment unit is used to judge in real time whether the motor driving torque value after each adjustment is greater than the maximum driving torque value of the motor during the process of gradually adjusting the motor driving torque value to the motor target driving torque value;

If yes, the maximum driving torque value is output;

Otherwise, output the motor driving torque value.

Optionally, the motor maximum driving torque value acquisition unit includes:

Retrieve the subunit to obtain the relationship curve between the rear wheel speed and the maximum driving torque value of the motor;

The motor maximum driving torque value acquisition subunit is used to obtain the motor maximum driving torque value based on the relationship curve between the rear wheel speed and the motor maximum driving torque value and the rear wheel speed.

The electric vehicle push-cart mode speed control device provided by the embodiments of the present application can execute the electric vehicle push-cart mode speed control method provided by any embodiment of the present application, and has functional modules and beneficial effects corresponding to the execution method.

It should be understood that various forms of the process shown above may be used, with steps reordered, added or deleted. For example, each step described in this application can be executed in parallel, sequentially, or in a different order. As long as the desired results of the technical solution of this application can be achieved, there is no limitation here.

Claims

A method for controlling the speed of an electric vehicle in push cart mode, including:

Based on the target mechanical gear and rear wheel speed, determine the estimated speed of the mid-mounted motor and the speed compensation value of the mid-mounted motor;

Determine the target speed value of the mid-mounted motor according to the estimated speed value and the speed compensation value;

Determine the motor target driving torque value of the mid-mounted motor according to the target speed value and the actual speed of the mid-mounted motor;

Within a preset time, the motor driving torque value of the mid-mounted motor is gradually adjusted to the motor target driving torque value.
The electric vehicle push mode speed control method according to claim 1, wherein the method for determining the estimated rotation speed of the mid-mounted motor includes:

According to the target mechanical gear, obtain the target sprocket ratio of the mid-mounted motor;

The estimated rotation speed is determined based on the rear wheel speed, the target sprocket ratio, and the transmission ratio of the mid-mounted motor.
The electric vehicle cart mode speed control method according to claim 1, after determining the rotational speed target value of the mid-mounted motor and before determining the motor target driving torque value of the mid-mounted motor, it further includes:

Determine the speed range of the mid-mounted motor according to the target vehicle speed, the maximum mechanical gear, the minimum mechanical gear, and the transmission ratio of the mid-mounted motor;

Determine whether the rotation speed target value is within the rotation speed range;

If not, reset the rotation speed target value according to the rotation speed range.
The electric vehicle cart mode speed control method according to claim 3, wherein the method for determining the rotation speed range of the mid-mounted motor includes:

Obtain the first sprocket ratio according to the maximum mechanical gear;

Determine the maximum speed value of the mid-mounted motor speed according to the target vehicle speed, the transmission ratio and the first sprocket ratio;

Obtain the second sprocket ratio according to the minimum mechanical gear;

According to the target vehicle speed, the transmission ratio and the second sprocket ratio, the minimum rotation speed value of the mid-mounted motor rotation speed is determined.
The electric vehicle push mode vehicle speed control method according to claim 1, wherein the method for determining the motor target driving torque value of the mid-mounted motor includes:

Obtain the actual speed of the mid-mounted motor;

According to the target speed value and the actual speed of the mid-mounted motor, a target difference value is obtained;

According to the target difference value, the target driving torque value of the motor is determined.
The electric vehicle push mode speed control method according to claim 5, wherein the method for obtaining the actual rotation speed of the mid-mounted motor includes:

Obtain the mechanical angle of the current sampling period of the mid-mounted motor, the mechanical angle of the previous sampling cycle of the mid-mounted motor, and the sampling frequency of the mechanical angle of the mid-mounted motor;

The actual rotation speed of the mid-mounted motor is calculated based on the mechanical angle of the mid-mounted motor in the current sampling period, the mechanical angle of the mid-mounted motor in the previous sampling cycle, and the sampling frequency of the mechanical angle of the mid-mounted motor.
The electric vehicle push mode speed control method according to claim 1, wherein the method of gradually adjusting the motor driving torque value of the mid-mounted motor to the motor target driving torque value includes:

According to the rear wheel speed, obtain the maximum driving torque value of the motor;

In the process of gradually adjusting the motor driving torque value to the motor target driving torque value, it is determined in real time whether the motor driving torque value after each adjustment is greater than the motor maximum driving torque value;

If so, output the maximum driving torque value;

Otherwise, the motor driving torque value is output.
The method for controlling the speed of an electric vehicle in push cart mode according to claim 1, wherein the motor driving torque value changes linearly within the preset time until it is equal to the motor target driving torque value.
The electric vehicle push mode speed control method according to claim 7, wherein the method for obtaining the maximum driving torque value of the motor includes:

Obtain the relationship curve between the rear wheel speed and the maximum driving torque value of the motor;

According to the relationship curve between the rear wheel speed and the maximum driving torque value of the motor and the rear wheel speed, the maximum driving torque value of the motor is obtained.
A speed control device for an electric vehicle in push-cart mode, including:

The first determination module is used to determine the speed estimate of the mid-mounted motor and the speed compensation value of the mid-mounted motor based on the target mechanical gear and the rear wheel speed;

a second determination module, configured to determine the target speed value of the mid-mounted motor according to the estimated speed value and the speed compensation value;

A third determination module, configured to determine the motor target driving torque value of the mid-mounted motor based on the target speed value and the actual speed of the mid-mounted motor;

The adjustment module is used to gradually adjust the motor drive torque value of the mid-mounted motor to the indicated motor target drive torque value within a preset time.