A pure electric vehicle anti-shake control method

Abstract

The application provides a kind of pure electric vehicle anti-shake control method, comprising: the compensation speed needed under different motor speed fluctuation acceleration is calibrated by test bench, and the corresponding table of speed fluctuation acceleration and compensation speed is established;Real-time acquisition of vehicle motor speed signal, and the motor speed signal is filtered to remove the influence of high-frequency noise and random load on motor speed;The speed fluctuation acceleration and motor speed of motor in the set period are calculated according to the filtered motor speed signal, and the corresponding compensation speed is obtained through the corresponding table;Anti-shake compensation torque is calculated according to the motor speed and the compensation speed, and the compensation torque is superimposed on the request torque output by the vehicle controller to suppress vehicle jitter.The application can reduce vehicle jitter and improve user comfort.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anti-shake control of electric vehicles, in particular to an anti-shake control method for pure electric vehicles. BACKGROUND

[0002] The power system of an electric vehicle includes a vehicle control system, an electric drive system and a power battery system. The vehicle control system converts driving requirements into a demand torque instruction and sends it to the electric drive system. The electric drive system outputs torque to drive the vehicle according to the demand torque instruction and in combination with its own output capability. For a front-engine front-drive vehicle, the electric drive system usually includes a motor, a reducer, a drive shaft and a wheel end. The components of the electric drive system are rigidly connected and form an under-damped system, which is prone to damped oscillation and causes the vehicle to shake. The speed fluctuation in the low-speed region is easily perceived by the driver and affects the driving comfort. Therefore, it is of great significance to control the electric vehicle to prevent shaking and improve user comfort. SUMMARY

[0003] The present application provides an anti-shake control method for pure electric vehicles, which solves the problem of damped oscillation and vehicle shaking caused by the rotation of the electric drive system components of the existing electric vehicle, reduces vehicle shaking and improves user comfort.

[0004] To achieve the above object, the present application provides the following technical scheme:

[0005] An anti-shake control method for pure electric vehicles, comprising:

[0006] Compensating the speed fluctuation acceleration of the motor under different motor speed fluctuations through bench calibration, and establishing a corresponding table of speed fluctuation acceleration and compensating speed;

[0007] Real-time acquisition of the motor speed signal of the vehicle, and filtering processing of the motor speed signal to remove the influence of high-frequency noise and random load on the motor speed;

[0008] Calculation of the motor speed fluctuation acceleration and motor speed in a set period according to the filtered motor speed signal, and obtaining the corresponding compensating speed through the corresponding table;

[0009] Calculation of the anti-shake compensation torque according to the motor speed and the compensating speed, and superposition of the compensation torque on the request torque output by the vehicle controller to suppress vehicle shaking.

[0010] Preferably, it further comprises:

[0011] Setting the vehicle to enter the vehicle anti-shake control in the starting and low-speed working conditions, and starting the anti-shake function when the motor speed is 5rpm-N, wherein N is the motor speed corresponding to 30km / h of the vehicle.

[0012] Preferably, the anti-shake compensation coefficient is calculated according to the current vehicle motor speed and the requested torque of the vehicle controller by table lookup.

[0013] A two-dimensional table of anti-shake compensation torque coefficients under different speeds and different torque conditions is obtained by calibration, and the anti-shake compensation torque coefficient is obtained by table lookup.

[0014] Preferably, the anti-shake compensation torque is calculated according to the motor speed and the compensation speed.

[0015] The anti-shake compensation coefficient is calculated according to the current vehicle motor speed and the requested torque of the vehicle controller by table lookup, the motor speed filtered from high-frequency noise is subtracted from the result of the compensation speed and the non-desired speed, and the anti-shake compensation coefficient is multiplied to calculate the anti-shake compensation torque.

[0016] Preferably, the anti-shake compensation torque calculated according to the motor speed and the compensation speed further comprises:

[0017] The motor speed without high-frequency signal is subtracted from the motor speed without random vibration, and the motor jitter speed is obtained after subtracting the compensation speed, and the anti-shake compensation torque is calculated by multiplying the motor jitter speed by the anti-shake compensation coefficient.

[0018] Preferably, it further comprises:

[0019] According to the current vehicle controller request torque instruction, the maximum torque allowed under the request torque instruction is obtained, and the maximum torque is taken as the request torque.

[0020] Preferably, it further comprises:

[0021] Determine whether the anti-shake compensation torque is greater than the maximum compensation torque limit value allowed under the current working condition, if yes, the anti-shake compensation torque takes the maximum compensation torque limit value as the anti-shake compensation torque value.

[0022] The anti-shake compensation torque is superimposed on the instruction torque of the vehicle controller to obtain the actual torque of the motor, and the obtained actual torque of the motor is limited within the motor external characteristic torque range.

[0023] The present application provides a kind of pure electric vehicle anti-shake control method, establishes the corresponding table of speed fluctuation acceleration and compensation speed, calculates the speed fluctuation acceleration according to current motor speed, and obtains the corresponding compensation speed by table lookup, and then calculates the anti-shake compensation torque, solves the problem that the parts of existing electric vehicle electric drive system are prone to decay oscillation when rotating, leading to vehicle shaking, which can reduce vehicle shaking and improve user comfort. BRIEF DESCRIPTION OF DRAWINGS

[0024] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

[0025] Figure 1 This is a schematic diagram of a vibration control method for a pure electric vehicle provided by the present invention.

[0026] Figure 2 A flowchart of a pure electric vehicle anti-shake control logic is provided for an embodiment of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the embodiments of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and implementation methods.

[0028] To address the issue of vibration in electric vehicles at low speeds, this invention provides a vibration control method for pure electric vehicles. This method solves the problem of damped oscillations caused by the rotation of components in the electric drive system of existing electric vehicles, which leads to vehicle vibration. It can reduce vehicle vibration and improve user comfort.

[0029] like Figure 1 As shown, a method for stabilizing vibrations in a pure electric vehicle includes:

[0030] S1: The required compensation speed under different motor speed fluctuation accelerations is determined by bench calibration, and a correspondence table between speed fluctuation acceleration and compensation speed is established.

[0031] S2: Real-time acquisition of the vehicle's motor speed signal, and filtering of the motor speed signal to remove the influence of high-frequency noise and random load on the motor speed.

[0032] S3: Calculate the motor speed fluctuation acceleration and motor speed within a set time period based on the filtered motor speed signal, and obtain the corresponding compensation speed through the corresponding table.

[0033] S4: Calculate the anti-shake compensation torque based on the motor speed and the compensation speed, and add the compensation torque to the requested torque output by the vehicle controller to suppress vehicle vibration.

[0034] Specifically, based on the actual motor speed of the vehicle, it is determined whether the anti-shake entry condition is met. If the motor speed meets the set threshold, the anti-shake compensation torque flag is set to 1. The resolver signal is collected, and the motor speed signal is calculated. The motor speed signal is then passed through a first-order low-pass filter to filter out high-frequency noise and unwanted motor speed filters to eliminate the impact of random loads on motor speed. The acceleration of speed fluctuation is calculated using the collected motor speed signal. The compensation speed is obtained by looking up the current speed fluctuation acceleration value in a table, and then the compensation torque is obtained. The anti-shake compensation torque is superimposed on the VCU request torque command, thereby suppressing vehicle vibration and improving driving smoothness.

[0035] The method also includes: setting the vehicle to enter vehicle anti-shake control under starting and low speed conditions, and activating the anti-shake function when the motor speed is between 5 rpm and N, where N is the motor speed corresponding to 30 km / h of the vehicle.

[0036] Furthermore, the step of calculating the anti-shake compensation coefficient by looking up a table based on the current vehicle motor speed and the requested torque of the vehicle controller includes:

[0037] A two-dimensional table of anti-shake compensation torque coefficients under different speed and torque conditions is obtained by calibration, and the anti-shake compensation torque coefficients are obtained by looking up the table.

[0038] Furthermore, the step of calculating the anti-vibration compensation torque based on the motor speed and the compensation speed includes:

[0039] The anti-shake compensation coefficient is calculated by looking up a table based on the current vehicle motor speed and the requested torque of the vehicle controller. The anti-shake compensation torque is calculated by multiplying the result of subtracting the compensation speed and the non-desired speed from the motor speed that filters high-frequency noise by the anti-shake compensation coefficient.

[0040] Furthermore, the step of calculating the anti-vibration compensation torque based on the motor speed and the compensation speed also includes:

[0041] The motor speed without random vibration is subtracted from the motor speed without high-frequency signal. After subtracting the compensation speed, the motor vibration speed is obtained. The motor vibration speed is then multiplied by the anti-vibration compensation coefficient to calculate the anti-vibration compensation torque.

[0042] The method also includes:

[0043] Based on the requested torque command from the current vehicle controller, obtain the maximum allowable torque under the requested torque command, and use the maximum torque as the requested torque.

[0044] The method also includes:

[0045] Determine whether the anti-shake compensation torque is greater than the maximum compensation torque limit allowed under the current operating conditions. If so, the anti-shake compensation torque will use the maximum compensation torque limit as the anti-shake compensation torque value.

[0046] The anti-shake compensation torque is superimposed on the command torque of the vehicle controller to obtain the actual torque of the motor, and the obtained actual torque of the motor is limited within the range of the motor's external characteristic torque.

[0047] In one embodiment, such as Figure 2 As shown, the vibration stabilization control process for electric vehicles is as follows:

[0048] ① Calculate the acceleration due to rotational speed fluctuation (ACC):

[0049] The system period is 20ms, and V T It is the motor speed at the current moment, V T-1 It is the motor speed at the previous moment. By superimposing the speed differences within 50 cycles, the acceleration of the speed fluctuation can be obtained.

[0050] ② Calculate the compensation speed:

[0051] Based on the speed fluctuation acceleration ACC, the compensation speed is calculated by referring to the table, and the required compensation speed under different speed accelerations is calibrated in advance.

[0052] ③ Determine if the anti-shake function is activated. Based on experience, vehicle vibration mainly occurs during vehicle start-up and low-speed operation. Considering the impact of anti-shake compensation torque on the overall vehicle power, the anti-shake activation condition is set as follows: the motor speed is between 5 rpm and n, where N is the motor speed corresponding to 30 km / h of the vehicle. When the above conditions are met, the anti-shake function is activated.

[0053] ③ Calculate the maximum stabilization torque:

[0054] Based on the current VCU torque command, the maximum allowable torque under the requested torque of the VCU is calculated by looking up the table. The maximum allowable torque for different VCU torques has been pre-calibrated.

[0055] ④ Extracting motor speed without high-frequency signals

[0056] By using a first-order low-pass filter, the collected motor speed is filtered to remove high-frequency noise. The filter coefficient was determined by bench testing and verified by the whole vehicle, which can meet the requirements of the whole vehicle under different speed conditions.

[0057] The motor speed without a high-frequency signal is SpeedNew = (1-a)*SpeedNew1-a*V, where SpeedNew1 is the motor speed value output by the filter at the previous moment, V is the motor speed at the current moment, and a is the filter coefficient.

[0058] ⑤ Extract the motor speed Speed ​​without random vibration:

[0059] After processing the collected motor speed using a first-order low-pass filter 2, the motor speed fluctuations caused by random vibrations are filtered out.

[0060] The motor speed without random vibration is Speed ​​= (1-b)*Speed1-b*V, where Speed1 is the motor speed value output by the filter at the previous moment, V is the motor speed at the current moment, and b is the filter coefficient.

[0061] ⑥ Calculate the jitter speed:

[0062] Subtracting the motor speed without random vibration from the motor speed without high-frequency signals, and then subtracting the compensation speed, yields the motor vibration speed V. d .

[0063] ⑦ Calculate the image stabilization compensation torque:

[0064] Based on the vehicle's current motor speed and VCU command torque, the anti-shake compensation torque coefficient is calculated by referring to a table. The two-dimensional table of anti-shake compensation coefficients has been calibrated in advance. Multiplying the shaking speed by the anti-shake compensation coefficient yields the anti-shake compensation torque.

[0065] ⑧ Output motor torque:

[0066] Determine whether the anti-vibration torque is greater than the maximum compensation torque limit allowed under the current operating conditions. If it exceeds the anti-vibration torque limit, the anti-vibration compensation torque is taken as the maximum compensation torque limit. The anti-vibration compensation torque is then superimposed on the VCU command torque to obtain the actual motor torque, and the obtained motor torque is limited to the range of the motor's external characteristic torque.

[0067] As can be seen, the present invention provides a method for anti-shake control of pure electric vehicles. It establishes a correspondence table between speed fluctuation acceleration and compensation speed, calculates the speed fluctuation acceleration based on the current motor speed, and obtains the corresponding compensation speed by looking up the table. Then, it calculates the anti-shake compensation torque, which solves the problem that the electric drive system components of existing electric vehicles are prone to damped oscillation when rotating, causing vehicle shaking. It can reduce vehicle shaking and improve user comfort.

[0068] The structure, features, and effects of the present invention have been described in detail above with reference to the embodiments shown in the figures. The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall be within the protection scope of the present invention as long as they do not exceed the spirit covered by the specification and figures.

Claims

1. A method for stabilizing vibrations in a pure electric vehicle, characterized in that, include: The required compensation speed under different motor speed fluctuation accelerations was determined by bench calibration, and a correspondence table between speed fluctuation acceleration and compensation speed was established. The vehicle's motor speed signal is acquired in real time and filtered to remove the influence of high-frequency noise and random load on the motor speed. The motor speed fluctuation acceleration and motor speed within a set time period are calculated based on the filtered motor speed signal, and the corresponding compensation speed is obtained through the corresponding table. The anti-vibration compensation torque is calculated based on the motor speed and the compensation speed, and the compensation torque is superimposed on the requested torque output by the vehicle controller to suppress vehicle vibration. The step of calculating the anti-vibration compensation torque based on the motor speed and the compensation speed includes: The anti-shake compensation coefficient is calculated by looking up a table based on the current vehicle motor speed and the requested torque of the vehicle controller. The anti-shake compensation torque is calculated by multiplying the result of subtracting the compensation speed and the non-desired speed from the motor speed that filters high-frequency noise by the anti-shake compensation coefficient.

2. The anti-shake control method for pure electric vehicles according to claim 1, characterized in that, Also includes: The vehicle is set to enter anti-shake control during start-up and low-speed operation, and the anti-shake function is activated when the motor speed is between 5 rpm and N, where N is the motor speed corresponding to 30 km / h of the vehicle.

3. The anti-shake control method for pure electric vehicles according to claim 2, characterized in that, The anti-shake compensation coefficient is calculated by looking up a table based on the current vehicle motor speed and the requested torque of the vehicle controller, including: A two-dimensional table of anti-shake compensation torque coefficients under different speed and torque conditions is obtained by calibration, and the anti-shake compensation torque coefficients are obtained by looking up the table.

4. The anti-shake control method for pure electric vehicles according to claim 3, characterized in that, The step of calculating the anti-vibration compensation torque based on the motor speed and the compensation speed also includes: The motor speed without random vibration is subtracted from the motor speed without high-frequency signal. After subtracting the compensation speed, the motor vibration speed is obtained. The motor vibration speed is then multiplied by the anti-vibration compensation coefficient to calculate the anti-vibration compensation torque.

5. The anti-shake control method for pure electric vehicles according to claim 4, characterized in that, Also includes: Based on the requested torque command from the current vehicle controller, obtain the maximum allowable torque under the requested torque command, and use the maximum torque as the requested torque.

6. The anti-shake control method for pure electric vehicles according to claim 5, characterized in that, Also includes: Determine whether the anti-shake compensation torque is greater than the maximum compensation torque limit allowed under the current operating conditions. If so, the anti-shake compensation torque will use the maximum compensation torque limit as the anti-shake compensation torque value. The anti-shake compensation torque is superimposed on the command torque of the vehicle controller to obtain the actual torque of the motor, and the obtained actual torque of the motor is limited within the range of the motor's external characteristic torque.

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