阅读说明：本技术 一种电动车辆起步抖动抑制方法及装置 (Method and device for suppressing starting jitter of electric vehicle ) 是由 刘斌 谢富科 于 2020-07-01 设计创作，主要内容包括：本发明涉及一种电动车辆起步抖动抑制方法及装置,属于汽车噪声抑制领域。本发明首先确定电动车辆中动力总成悬置系统绕扭矩轴的固有频率,从而确定电动车辆中动力总成悬置系统绕扭矩轴的固有周期,然后再根据电机冲击响应谱特性选择动载系数最小值所对应的扭矩稳定时间与固有周期的比值,根据该比值以及油门开度百分比来对扭矩稳定时间进行标定,根据标定所得扭矩稳定时间进行车辆起步控制,便可以使整车动力性和抖动抑制性达到最优。(The invention relates to a method and a device for suppressing starting jitter of an electric vehicle, and belongs to the field of automobile noise suppression. The method comprises the steps of firstly determining the natural frequency of a power assembly suspension system in the electric vehicle around a torque shaft, thereby determining the natural period of the power assembly suspension system in the electric vehicle around the torque shaft, then selecting the ratio of the torque stabilization time corresponding to the minimum value of the dynamic load coefficient to the natural period according to the characteristics of the motor impact response spectrum, calibrating the torque stabilization time according to the ratio and the percentage of the opening degree of an accelerator, and carrying out vehicle starting control according to the calibrated torque stabilization time, so that the power performance and the jitter suppression performance of the whole vehicle can be optimal.)

1. An electric vehicle start judder suppression method, characterized by comprising:

1) determining a natural frequency f of a power assembly suspension system in the electric vehicle around a torque axis, and calculating a natural period T of the power assembly suspension system around the torque axis according to the natural frequency f, wherein T is 1/f;

2) acquiring a motor impact response spectrum, determining the characteristics of the motor impact response spectrum, and further selecting an n value corresponding to the minimum value of the dynamic load coefficient; the motor impact response spectrum characteristic is the relation between an n value and a dynamic load coefficient; the n value is the ratio of the torque stabilization time T to the inherent period T; the torque stabilization time t is the time for the torque of the motor to reach a stable value from zero after the motor is started;

3) calibrating the torque stabilization time t by taking the complete vehicle dynamic property and the jitter suppression property as the optimal targets, and determining the torque stabilization time t under the set accelerator opening percentage and the selected n value;

4) and performing vehicle starting control according to the torque stabilization time t.

2. The electric vehicle startup shake suppression method according to claim 1, characterized in that the types of the motor impulse response spectrum characteristics include a diagonal step type, a normal vector type, and a cycloid type.

3. The electric vehicle starting shake suppression method according to claim 1 or 2, characterized in that when the motor shock response spectrum characteristic is a diagonal step type, n-1, 2, or 3 is selected.

4. The electric vehicle starting shake suppression method according to claim 1 or 2, characterized in that when the motor shock response spectrum characteristic is of a positive vector type, n-1.5 or 3 is selected.

5. The electric vehicle starting shake suppression method according to claim 1 or 2, characterized in that when the motor shock response spectrum characteristic is a cycloid type, n-2 is selected.

6. An electric vehicle start judder suppression device, characterized by comprising a memory and a processor for executing a computer program stored in the memory to implement the electric vehicle start judder suppression method as follows:

1) determining a natural frequency f of a power assembly suspension system in the electric vehicle around a torque axis, and calculating a natural period T of the power assembly suspension system around the torque axis according to the natural frequency f, wherein T is 1/f;

2) acquiring a motor impact response spectrum, determining the characteristics of the motor impact response spectrum, and further selecting an n value corresponding to the minimum value of the dynamic load coefficient; the motor impact response spectrum characteristic is the relation between an n value and a dynamic load coefficient; the n value is the ratio of the torque stabilization time T to the inherent period T; the torque stabilization time t is the time for the torque of the motor to reach a stable value from zero after the motor is started;

3) calibrating the torque stabilization time t by taking the complete vehicle dynamic property and the jitter suppression property as the optimal targets, and determining the torque stabilization time t under the set accelerator opening percentage and the selected n value;

4) and performing vehicle starting control according to the torque stabilization time t.

7. The electric vehicle startup shake suppression device according to claim 6, wherein the types of the motor impulse response spectrum characteristics include a diagonal step type, a positive vector type, and a cycloid type.

8. The electric vehicle starting shake suppression device according to claim 6 or 7, wherein when the motor shock response spectrum characteristic is a diagonal step type, n-1, 2, or 3 is selected.

9. The electric vehicle starting shake suppression device according to claim 6 or 7, characterized in that when the motor shock response spectrum characteristic is of a positive vector type, n is 1.5 or 3.

10. The electric vehicle starting judder suppression device according to claim 6 or 7, wherein when the motor shock response spectrum characteristic is a cycloid type, n-2 is selected.

Technical Field

The invention relates to a method and a device for suppressing starting jitter of an electric vehicle, and belongs to the field of automobile noise suppression.

Background

With the social development, people's environmental awareness is gradually improved, and the electric automobile market is more and more popular. However, the electric automobile has large torque at the moment of starting and is correspondingly fast, so that the problems of motor vibration, transmission system knocking and the like are more easily caused.

At present, aiming at the problems of starting shake and knocking of the electric automobile, the conventional solution is to increase the modal frequency of the power assembly around the axial direction or change the accelerator response characteristic to reduce the accelerator response speed. Increasing the modal frequency of the power assembly around the axial direction can be realized by improving the shock resistance of the suspension system, and particularly, if a nearly solid rubber suspension cushion is adopted, the rigidity of the suspension cushion is increased, and the limit capability of the cushion is improved; the reduction of the accelerator response speed can be realized by increasing the torque rising time of the motor, so that the impact caused by large and fast torque change is improved.

However, the adoption of the nearly solid over-rigid rubber suspension cushion sacrifices the vibration isolation capability of the vehicle suspension system, which is not beneficial to improving the riding comfort; the method for reducing the accelerator response speed to change the motor torque response speed influences the power and acceleration performance of the whole vehicle, and usually needs to sacrifice the dynamic property to a great extent in order to really achieve the effect of inhibiting the starting shake of the whole vehicle, and the driving safety can be directly influenced by the lack of the dynamic property of the whole vehicle.

It can be seen that the starting shaking suppression methods of the electric vehicles in the prior art all have obvious limitations, and a new starting shaking suppression method of the electric vehicles, which can overcome the limitations, needs to be provided.

Disclosure of Invention

The invention aims to provide a method and a device for suppressing starting shaking of an electric vehicle, and aims to solve the problem that the methods for suppressing starting shaking of the electric vehicle in the prior art have obvious limitations.

In order to achieve the above object, the present invention provides a starting judder suppressing method for an electric vehicle, comprising the steps of:

1) determining a natural frequency f of a power assembly suspension system in the electric vehicle around a torque axis, and calculating a natural period T of the power assembly suspension system around the torque axis according to the natural frequency f, wherein T is 1/f;

2) acquiring a motor impact response spectrum, determining the characteristics of the motor impact response spectrum, and further selecting an n value corresponding to the minimum value of the dynamic load coefficient; the motor impact response spectrum characteristic is the relation between an n value and a dynamic load coefficient; the n value is the ratio of the torque stabilization time T to the inherent period T; the torque stabilization time t is the time for the torque of the motor to reach a stable value from zero after the motor is started;

3) calibrating the torque stabilization time t by taking the complete vehicle dynamic property and the jitter suppression property as the optimal targets, and determining the torque stabilization time t under the set accelerator opening percentage and the selected n value;

4) and performing vehicle starting control according to the torque stabilization time t.

The invention has the beneficial effects that:

the method comprises the steps of firstly determining the natural frequency f of the power assembly suspension system around the torque shaft, thereby determining the natural period T of the power assembly suspension system around the torque shaft, then selecting the n value corresponding to the minimum value of the dynamic load coefficient by combining the characteristics of the motor impact response spectrum, completing the calibration of the torque stable time T according to the determined n value and the opening percentage of the accelerator, and completing the vehicle starting control by utilizing the torque stable time T obtained by the calibration, so that the power performance and the jitter suppression performance of the whole vehicle can be optimized, and the power performance of the whole vehicle is ensured while the vehicle starting jitter suppression is completed.

Further, the types of the motor impulse response spectrum characteristics include a diagonal step type, a positive vector type and a cycloid type.

Further, when the motor shock response spectrum characteristic is in a slope line step type, n is 1, 2 or 3.

Further, when the motor shock response spectrum characteristic is of a positive vector type, n is 1.5 or 3.

Further, when the motor shock response spectrum characteristic is a cycloid type, n is 2.

In order to achieve the above object, the present invention further provides an electric vehicle start judder suppression device, which includes a memory and a processor, wherein the processor is configured to execute a computer program stored in the memory, so as to implement the following electric vehicle start judder suppression method:

1) determining a natural frequency f of a power assembly suspension system in the electric vehicle around a torque axis, and calculating a natural period T of the power assembly suspension system around the torque axis according to the natural frequency f, wherein T is 1/f;

2) acquiring a motor impact response spectrum, determining the characteristics of the motor impact response spectrum, and further selecting an n value corresponding to the minimum value of the dynamic load coefficient; the motor impact response spectrum characteristic is the relation between an n value and a dynamic load coefficient; the n value is the ratio of the torque stabilization time T to the inherent period T; the torque stabilization time t is the time for the torque of the motor to reach a stable value from zero after the motor is started;

3) calibrating the torque stabilization time t by taking the complete vehicle dynamic property and the jitter suppression property as the optimal targets, and determining the torque stabilization time t under the set accelerator opening percentage and the selected n value;

4) and performing vehicle starting control according to the torque stabilization time t.

The invention has the beneficial effects that:

the method comprises the steps of firstly determining the natural frequency f of the power assembly suspension system around the torque shaft, thereby determining the natural period T of the power assembly suspension system around the torque shaft, then selecting the n value corresponding to the minimum value of the dynamic load coefficient by combining the characteristics of the motor impact response spectrum, completing the calibration of the torque stable time T according to the determined n value and the opening percentage of the accelerator, and completing the vehicle starting control by utilizing the torque stable time T obtained by the calibration, so that the power performance and the jitter suppression performance of the whole vehicle can be optimized, and the power performance of the whole vehicle is ensured while the vehicle starting jitter suppression is completed.

Further, the types of the motor impulse response spectrum characteristics include a diagonal step type, a positive vector type and a cycloid type.

Further, when the motor shock response spectrum characteristic is in a slope line step type, n is 1, 2 or 3.

Further, when the motor shock response spectrum characteristic is of a positive vector type, n is 1.5 or 3.

Further, when the motor shock response spectrum characteristic is a cycloid type, n is 2.

Drawings

FIG. 1 is a flow chart of an electric vehicle start judder suppression method in accordance with the present invention;

FIG. 2 is a diagram showing the characteristics of an impact response spectrum of the slant line step type according to an embodiment of the present invention.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings.

The embodiment of the method provided by the invention comprises the following steps:

fig. 1 shows a flowchart of the start shaking suppression method for an electric vehicle according to the present invention, which includes the following steps:

1. the natural frequency of the powertrain suspension system about the torque axis is determined, thereby determining the natural period of the powertrain suspension system about the torque axis.

In this embodiment, the design of the powertrain suspension system is performed first, so as to determine the natural frequency of the powertrain suspension system around the torque axis and obtain the natural period of the powertrain suspension system around the torque axis.

The method comprises the steps of testing parameters such as rotational inertia and a mass center position of a power assembly suspension system through a three-wire pendulum or other mass center rotational inertia test stand, determining a proper suspension center point position and optimizing suspension rigidity parameters by using suspension design software such as ADAMS (adaptive dynamic analysis system), optimally designing the power assembly suspension system, enabling the decoupling rate of the power assembly suspension in the direction (Roll X) around a torque axis to reach more than 90%, simultaneously calculating the natural frequency f of the power assembly suspension around the torque axis, and calculating the natural period T of the power assembly suspension around the torque axis according to the relation of T1/f.

Since the higher the natural frequency f of Roll X represents the stronger the suspension system can resist the torsion of the powertrain, the higher the natural frequency f is, the better the natural frequency f is, when the suspension system of the powertrain is optimally designed, but considering that the suspension system is also expected to have good vibration isolation capability, the value range of the natural frequency f is limited to 20Hz to 40Hz by the design in the present embodiment.

In addition, the suspension rubber cushion can be selected to be a solid rubber cushion structure, so that the natural frequency f is improved to improve the torsion resistance of the power assembly of the suspension system.

2. And calibrating the torque stabilization time of the motor according to the shock response spectrum characteristic of the motor.

After the design of the suspension system is completed, the structure of the power assembly suspension system is uniquely determined, and the inherent period T of the power assembly suspension system around the torque axis is also determined. After the inherent period T of the powertrain suspension system around the torque axis is determined, the motor torque stabilization time T can be calibrated. The motor torque stabilization time t is a time required for the motor torque to reach a certain stable value after the motor is started.

The specific calibration contents of the motor torque stabilization time t comprise:

first, it is determined which of a ramp step type, a normal vector type, and a cycloid type the shock response spectrum characteristic of the motor belongs to, by motor information provided by a motor supplier. As shown in fig. 2, in this embodiment, the impact response spectrum characteristic of the motor is taken as an example that:

when the opening of the accelerator is 100%, the ratio n of the torque stabilization time T to the inherent period T of the power assembly suspension around the torque axis is 1, the torque stabilization time T can be calibrated according to the expected value, and the torque stabilization time T is selected in a set range approximately equal to the fixed period T, so that the dynamic performance and the jitter suppression performance of the whole vehicle can be optimal.

When the accelerator opening is 70%, the ratio n of the torque stabilization time T to the inherent period T of the powertrain suspension around the torque shaft is 2, the torque stabilization time T is calibrated according to the expected value, and the torque stabilization time T is selected in a set range approximately equal to twice the fixed period T.

When the accelerator opening is 50%, the ratio n of the torque stabilization time T to the inherent period T of the powertrain suspension around the torque shaft is 3, the torque stabilization time T is calibrated according to the expected value, and the torque stabilization time T is selected in a set range approximately equal to three times of the fixed period T.

Because the calibration experiment cost is usually high and time is consumed, the torque stabilization time t under all the accelerator opening conditions is difficult to calibrate, and in the embodiment, after calibrating a plurality of typical opening percentages, the stabilization time corresponding to other opening percentages is obtained in a difference mode. Thus, a correspondence table of the accelerator opening degree and the torque stabilization time t shown in the following table is obtained and used for driving control during actual running of the vehicle.

And storing the table in a memory, looking up a table by a processor according to the current throttle percentage during operation to select a corresponding t value, and using the t value in the vehicle starting control process.

The storage in the form of a table and the table look-up are one way to realize the control, and as other implementation manners, a function representing the relationship between the accelerator opening percentage and the torque stabilization time t can be fitted according to calibrated data, and when starting control is performed, the corresponding torque stabilization time t is calculated according to the current accelerator opening percentage and the function.

In the calibration process of the embodiment, the ratio n is less than or equal to 3, so that the torque stabilization time t is not too long, and the power and acceleration performance of the whole vehicle are ensured.

In addition, in order to ensure the acceleration performance, the n values corresponding to the throttle opening percentage can be selected to be 1.

In this embodiment, the reason why the suppression of the vehicle shaking and the transmission system knocking can be realized by calibrating the torque stabilization time t is as follows:

as can be seen from fig. 2, in this embodiment, when calibrating the torque stabilization time T, the dynamic load coefficient V corresponding to the ratio n (T/T) can be controlled by making the ratio n between the torque stabilization time T and the natural frequency T approach to an integer multiple of 1_max/F (maximum response V of suspension system)_maxThe ratio to the static response F) approaches its minimum value.

Coefficient of dynamic load V_maxWhen the minimum value of the force is obtained, the maximum stress of the power assembly suspension system is equal to the static working condition, the force transmitted by the motor to the suspension system is minimum, and the vibration caused by the motor is also minimum; at the same time, the drive train moves to the equilibrium position at time t, and remains stationary after that, without residual vibrations. Because the force transmitted by the motor to the suspension system is minimum and the power assembly moves to the balance position just at the moment t, the problems of starting shake of the whole vehicle and knocking of the transmission system can be solvedAnd (5) problems are solved.

The calibration process is specifically described in the case that the shock response spectrum characteristic of the motor belongs to a diagonal step type, and when the shock response spectrum characteristic of the motor belongs to a normal vector type, similarly, in order to prevent jitter, the ratio n between the torque stabilization time T and the natural frequency T needs to be controlled to be a corresponding multiple, such as an integral multiple of 1.5; if the shock response spectrum characteristic of the motor belongs to a cycloid type, the ratio n between the torque stabilization time T and the natural frequency T needs to be controlled to be an integral multiple of 2.

In addition, the invention also provides an embodiment of the device:

the electric vehicle starting shaking suppression device comprises a memory, a processor and a computer program which is stored in the memory and can run on the processor, wherein when the processor executes the program, the electric vehicle starting shaking suppression device realizes the electric vehicle starting shaking suppression method of the method embodiment.

The device can be intelligent equipment such as a whole vehicle processor, a tablet personal computer, a mobile phone or a personal computer.

When the specific programming is performed, since knowledge of the programming language such as syntax is common knowledge in the art, it is fully within the ability of the skilled person to perform the corresponding programming by using the existing programming language (for example, C language, JAVA, assembly language, C #, C + +, etc.) according to the specific processing method for enhancing the infrared temperature measurement image of the power device of the present invention, and this process is not described herein again.

The specific embodiments are given above, but the present invention is not limited to the described embodiments. The basic idea of the present invention is to provide the basic solution described above, and variations, modifications, replacements, and variations of the embodiments can be made without departing from the principle and spirit of the present invention, and still fall within the protection scope of the present invention.