CN114734798A

CN114734798A - Vehicle and control method of the vehicle

Info

Publication number: CN114734798A
Application number: CN202210466003.9A
Authority: CN
Inventors: 袁仪
Original assignee: Weilai Power Technology Hefei Co Ltd
Current assignee: Weilai Power Technology Hefei Co Ltd
Priority date: 2022-04-26
Filing date: 2022-04-26
Publication date: 2022-07-12

Abstract

The invention relates to the technical field of vehicles, and particularly provides a vehicle and a control method of the vehicle. In order to solve the problem that the existing vehicle is seriously influenced by other vibration signals when the health degree of the electric drive system is detected, the vehicle comprises the electric drive system and a wheel transmission shaft, wherein the electric drive system is provided with a gear box for outputting power to the wheel transmission shaft, and a coupling device is arranged between an output shaft of the gear box and the wheel transmission shaft. The decoupling device is disconnected to enable the electric drive system and the wheel transmission shaft to be decoupled, decoupling between electric drive rotation and vehicle running can be achieved, the electric drive rotation is achieved under the condition that the vehicle does not run, then the vibration value of the electric drive system is obtained through the vibration sensor, the health state of the electric drive system is judged, the influence of tire noise, road noise and noise of other parts is effectively avoided, conditions are provided for the vibration sensor to obtain a signal with a high signal to noise ratio, the measured vibration value of the electric drive system is more accurate, and the detection result is more accurate.

Description

Vehicle and control method of the vehicle

Technical Field

The invention relates to the technical field of vehicles, and particularly provides a vehicle and a control method of the vehicle.

Background

The reliability of components and functions of a vehicle is a crucial subject of the industry, and in order to improve the reliability of the vehicle, monitoring equipment is used for monitoring the state of the components or the functions in real time, and potential failure parts are quickly identified and replaced, so that the improvement of the reliability of a system or the functions is one of important means in the field of vehicles. The electric drive system is a core component for ensuring the work of the electric automobile, the electric drive system drives the electric automobile to move, the electric drive system is composed of a mechanical component and an electrical component, and the reliability of the electric drive system is determined by the stability of each component.

In the prior art, when a vibration sensor is used for analyzing the health degree of mechanical parts in an electric drive system, a necessary condition is that the electric drive system needs to be in a running state, but when vibration information is collected, a vehicle can also be in a moving state, when the vehicle moves in a running process, besides a vibration signal sent by the electric drive system, other systems (such as steering, suspension and the like) on the vehicle can also start the vibration signal because the other systems are in a working state, wind noise, road noise and tire noise can be generated in the running process of the vehicle, and the vibration signal can also be indirectly generated, and the signals can seriously interfere the vibration sensor to collect an effective vibration signal of the electric drive system.

Accordingly, there is a need in the art for a new vehicle that addresses the problem of existing vehicles being severely affected by other vibration signals when performing health diagnostics on electric drive systems.

Disclosure of Invention

The invention aims to solve the technical problem that the existing vehicle is seriously influenced by other vibration signals when the health degree of the electric drive system is diagnosed.

In a first aspect, the present invention provides a vehicle comprising an electric drive system and a wheel drive shaft, the electric drive system being provided with a gearbox for outputting power to the wheel drive shaft, a coupling device being provided between an output shaft of the gearbox and the wheel drive shaft.

In a preferred embodiment of the vehicle, the coupling device is a friction plate clutch or a dog-tooth clutch.

The invention also provides a control method of the vehicle, wherein the vehicle is the vehicle in any one of the technical schemes; the control method of the vehicle includes:

controlling the vehicle to enter a diagnostic state;

controlling the coupling device to open after the vehicle enters the diagnostic state;

controlling the electric drive system to work;

acquiring a vibration value of the electric drive system;

and judging the health condition of the electric drive system according to the vibration value.

In a preferable embodiment of the control method of the vehicle, the step of "controlling the electric drive system to operate" further includes:

and controlling the electric drive system to work at a preset speed.

In a preferable aspect of the control method of the vehicle, the step of "controlling the vehicle to enter the diagnostic state" further includes:

acquiring the time of last diagnosis of the vehicle;

and controlling the vehicle to enter a diagnosis state when the time interval between the vehicle and the last diagnosis is larger than or equal to a first preset time.

In a preferred embodiment of the above vehicle control method, the step of controlling the vehicle to enter the diagnostic state when the time interval from the last diagnosis is greater than or equal to a first preset time further includes:

when the time interval between the vehicle and the last diagnosis is not less than first preset time, judging whether the vehicle is in a shutdown state or not;

controlling the vehicle to enter a diagnostic state when the vehicle is in a shut-down state.

In a preferable embodiment of the control method of the vehicle described above, after the step of "controlling the electric drive system to operate", the control method further includes:

judging whether the wheel transmission shaft rotates or not;

and controlling the electric drive system to be closed when the wheel transmission shaft rotates.

In a preferable embodiment of the control method of the vehicle described above, after the step of "determining the health of the electric drive system based on the vibration value", the control method further includes:

controlling the coupling device to engage; controlling the vehicle to end the diagnostic state.

In a preferable aspect of the control method of the vehicle described above, the step of "determining the health condition of the electric drive system based on the vibration value" further includes:

performing time domain signal analysis or frequency domain signal analysis on the obtained vibration value and a preset healthy vibration value;

obtaining a health of the electric drive system;

or substituting the obtained vibration value into a preset vibration value health data model for comparison and analysis;

a health of the electric drive system is obtained.

In a preferable aspect of the control method of the vehicle described above, after the step of "determining whether or not the wheel propeller shaft is rotating", the control method further includes:

and when the wheel transmission shaft does not rotate, acquiring the vibration value of the electric drive system.

As will be appreciated by those skilled in the art, the vehicle of the present invention includes an electric drive system and a wheel drive shaft, the electric drive system being provided with a gearbox for outputting power to the wheel drive shaft, a coupling device being provided between an output shaft of the gearbox and the wheel drive shaft.

In the case of the above technical solution, the vehicle according to the present invention is provided with the coupling device between the output shaft of the gear box of the electric drive system and the wheel drive shaft, so that the electric drive system is diagnosed individually without rotating the wheels by disconnecting the coupling device when the vehicle is in a standstill state. Particularly, the output shaft of the electric drive system is decoupled from the wheel transmission shaft through the coupling device, the electric drive rotation and the wheel rotation can be decoupled, namely the decoupling between the driving of the vehicle can be realized, the electric drive rotation is realized under the condition that the vehicle does not drive, the vibration value of the components in the electric drive system is obtained through the vibration sensor, the health state of the electric drive system is judged, the influence of the noise of tires, road noise and other components can be effectively avoided, conditions are provided for the vibration sensor to obtain a signal with a high signal-to-noise ratio, the measured vibration value of the electric drive system is more accurate, and the detection result is more accurate.

In addition, when the vehicle runs, the vehicle-mounted controller, the processor and each communication line are in a high-load working state, data analysis is carried out by using data collected by the vibration sensor, and the effectiveness of an analysis algorithm depends on the quality and the quantity of the data and the advancement of the algorithm. Thus, there is a need for both the power of the controller and the bandwidth of the communication line when using the monitoring system. According to the method, diagnosis is performed by using the time when the vehicle stops (for example, stops at night) through the independent work of the electric drive system, the diagnosis is performed by using the state that the vehicle does not run, and the calculation force and the communication bandwidth of the controller are both in an idle state, so that the vibration sensor can be fully used for high-frequency high-precision data acquisition, and an advanced complex algorithm can be deployed for diagnosis. Therefore, the active diagnosis system based on the disconnecting mechanism can realize time division multiplexing of hardware equipment for signal communication and processing, simultaneously reduce interference influence, reasonably use the maximum transmission path, improve the quality of signals, reduce the performance index requirements of the vibration sensor on one hand, and improve the diagnosis effect on the other hand.

Drawings

Preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

FIG. 1 is a schematic illustration of the connection of the electric drive system of the vehicle of the present invention to the wheel drive shafts;

FIG. 2 is a flow chart of the main steps of the control method of the vehicle of the invention;

FIG. 3 is a flow chart of the steps of one embodiment of a control method of a vehicle of the present invention;

fig. 4 is a flowchart of steps of another embodiment of a control method of a vehicle of the present invention.

List of reference numerals:

1. an electric drive system; 11. a motor; 12. a gear case; 121. a differential mechanism; 122. an input gear; 123. an output gear; 2. a wheel drive shaft; 3. a coupling device; 4. and (7) wheels.

Detailed Description

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention. And can be adjusted as needed by those skilled in the art to suit particular applications. For example, although the present application is described in connection with an electric vehicle, this is not limiting, and the vehicle of the present invention may be an electric tricycle, an electric bicycle, or the like, or may also be a hybrid vehicle.

It is to be understood that, in the description of the present invention, unless otherwise explicitly specified or limited, the term "connected" is to be interpreted broadly, e.g., as either a fixed connection, a removable connection, or an integral connection; may be a mechanical connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

As shown in fig. 1, in order to solve the problem that the existing vehicle is seriously affected by other vibration signals when the health degree of the electric drive system is diagnosed, the vehicle of the invention comprises an electric drive system 1 and a wheel transmission shaft 2, wherein two ends of the wheel transmission shaft 2 are connected with wheels 4 of the vehicle; the electric drive system 1 specifically comprises an electric motor 11 and a gear box 12, an output shaft of the electric motor 11 is connected with an input gear 122 of the gear box 12, an output gear 123 of the gear box 12 is connected with a differential 121, an output shaft (not shown in the figure) of the gear box 12 is arranged on the differential 121 for outputting power to the wheel transmission shafts 2, and a coupling device 3 is arranged between the output shaft of the gear box 12 and the wheel transmission shafts 2, so that the gear box 12 and the wheel transmission shafts 2 are coupled or decoupled through the coupling device 3. Fig. 1 is a schematic diagram of the coupling device 3 in a coupling state, and a decoupling state is not shown, but does not affect the understanding of those skilled in the art. Preferably, the coupling device 3 is a friction plate clutch or a dog clutch, and may also be a step motor dog clutch or an electromagnetic switch dog clutch, etc., so that there is no limitation on the type of the coupling device 3 as long as the coupling device 3 can couple and decouple the electric drive system 1 and the wheel transmission shaft 2, and a person skilled in the art can set the coupling device according to needs.

The setting mode has the advantages that: the vehicle of the invention diagnoses the electric drive system 1 without turning the wheels 4 by disconnecting the coupling device 3 when the vehicle is in a standstill state by providing the coupling device 3 between the output shaft of the gear box 12 of the electric drive system 1 and the wheel drive shaft 2. Specifically, the electric drive system 1 and the wheel transmission shaft 2 are decoupled through the coupling device 3, decoupling between electric drive rotation and wheel 4 rotation, namely vehicle running can be achieved, electric drive rotation is achieved under the condition that a vehicle does not run, then the vibration value of the electric drive system 1 is obtained through the vibration sensor, the health state of the electric drive system 1 is judged according to the vibration value, the influence of tire noise, road noise and noise of other parts can be effectively avoided, conditions are provided for the vibration sensor to obtain a signal with a high signal to noise ratio, the measured vibration value of the electric drive system 1 is more accurate, and the detection result is more accurate.

In addition, when the vehicle runs, the vehicle-mounted controller, the processor and each communication line are in a high-load working state, data analysis is carried out by using data collected by the vibration sensor, and the effectiveness of an analysis algorithm depends on the quality and the quantity of the data and the advancement of the algorithm. Thus, when using a monitoring system, there is a need for the computing power of the controller and the bandwidth of the communication line. According to the method, diagnosis is performed by using the time when the vehicle stops (for example, stops at night) through the independent work of the electric drive system 1, the diagnosis is performed by using the state that the vehicle does not run, and the calculation force and the communication bandwidth of the controller are both in an idle state, so that the vibration sensor can be fully used for high-frequency and high-precision data acquisition, and advanced and complex algorithms can be deployed for diagnosis. Therefore, the active diagnosis system based on the disconnecting mechanism can realize time division multiplexing of hardware equipment for signal communication and processing, simultaneously reduce interference influence, reasonably use the maximum transmission path, improve the quality of signals, reduce the performance index requirements of the vibration sensor on one hand, and improve the diagnosis effect on the other hand.

As mentioned in the first paragraph of this section, the above embodiments are only used for illustrating the principle of the present invention, and are not intended to limit the protection scope of the present invention, and those skilled in the art can make modifications to the above structures so that the present invention can be applied to more specific application scenarios without departing from the principle of the present invention.

Further, the present invention provides a control method of a vehicle having the vehicle described in any of the above embodiments. Referring to fig. 1, specifically, the vehicle includes an electric drive system 1 and a wheel drive shaft 2, the electric drive system 1 is provided with a gear box 12 for outputting power to the wheel drive shaft 2, and a coupling device 3 is provided between an output shaft of the gear box 12 and the wheel drive shaft 2;

referring to fig. 2, a control method of a vehicle includes:

step S01: controlling the vehicle to enter a diagnostic state;

step S011: after the vehicle enters a diagnosis state, controlling the coupling device to be disconnected;

step S012: controlling an electric drive system to work;

step S013: acquiring a vibration value of the electric drive system;

step S014: and judging the health condition of the electric drive system according to the vibration value.

The original software of the electrically-driven controller is modified, and the state machine for active diagnosis is added, so that the vehicle enters a diagnosis state firstly, the diagnosis state comprises that the vehicle is in a static state, devices of an air conditioner, a sound device and the like of the vehicle, which generate interference vibration signals, are in a closed state and are controlled not to be turned on, and the like, so that the vehicle is in an advantageous condition before the health diagnosis of the components, but the diagnosis state is not limited at all, and the diagnosis state can also comprise other states which are beneficial to the health diagnosis of the electric drive system 1. Further, after the vehicle enters a diagnosis state, the coupling device 3 is controlled to be disconnected, so that electric drive rotation and wheel 4 rotation are decoupled, namely vehicle running is performed, then the electric drive system 1 is controlled to work, the wheel transmission shaft 2 does not rotate along with the rotation of the output shaft of the gearbox 12, a vibration sensor, a communication interface and a cable are arranged on the vehicle, a diagnosis algorithm responding to development and deployment enters a relevant controller, a vibration value of a mechanical component of the electric drive system 1 is obtained through the vibration sensor, the health degradation or failure of the mechanical component can be reflected in abnormal vibration, and finally the health condition of the mechanical component is analyzed or judged through the deployed algorithm through the vibration value so as to obtain the health condition of the electric drive system 1. It should be noted that the vibration sensor may be disposed on any one of the components to be detected of the electric drive system 1, for example, volatile components such as various rotating mechanical components of the electric drive system 1.

In one possible embodiment, step S012 further includes:

and controlling the electric drive system to work at a preset speed.

The rotating speed of the electric drive system 1 is determined according to the driving condition of a vehicle, the failure frequency of mechanical vibration is related to the design and parameters of a mechanical structure, the transfer efficiency from a vibration excitation point to a vibration sensor is related to a transfer function in a transfer path, wherein, according to different modes, the transfer efficiency is higher in a plurality of frequency bands, and the energy of a vibration signal is further enhanced by actively controlling the rotating speed of the electric drive system 1 to enable the failure characteristic frequency to be matched with the maximum transfer efficiency frequency.

Further, referring to fig. 3, step S01 further includes:

step S0151: acquiring the last diagnosis time of the vehicle;

step S0152: when the time interval between the vehicle and the last diagnosis is larger than or equal to first preset time, judging whether the vehicle is in a shutdown state or not;

step S0153: controlling the vehicle to enter a diagnostic state when the vehicle is in a shut-down state;

step S0154: the vehicle is controlled not to enter the diagnostic state when the vehicle is not in the shut-down state.

The method comprises the steps of obtaining the time of last diagnosis of a vehicle, when the time interval from the last diagnosis is larger than a first preset time, wherein the first preset time is seven days, for example, the fact that the vehicle does not detect the electric drive system 1 for a long time and the health condition of the electric drive system 1 needs to be detected, then judging whether the vehicle is in a running stop state or not, for example, judging whether wheels 4 rotate or not through a sensor, and controlling the vehicle to enter a diagnosis state if the vehicle is in the running stop state, so that traffic accidents caused by vehicle stalling due to the fact that the vehicle enters the diagnosis state when the vehicle is still running are prevented.

Alternatively, in an alternative embodiment, step S01 further includes:

judging whether the vehicle is in a shutdown state or not;

the vehicle is controlled to enter a diagnostic state when the vehicle is in a shut-down state.

The state of the vehicle is detected directly before the vehicle enters the diagnostic state, which is not allowed when the vehicle is in the on state and which is controlled when the vehicle is in the off state.

Still alternatively, in another alternative embodiment, step S01 further includes:

acquiring the last diagnosis time of the vehicle;

and controlling the vehicle to enter a diagnosis state when the time interval with the last diagnosis is more than or equal to a first preset time.

The last diagnosis time of the vehicle is acquired, and if the time interval between the vehicle and the last diagnosis time is too long, the vehicle is controlled to enter the diagnosis state.

In the above embodiment, the running state of the vehicle is a state when the vehicle is in motion, and the shutdown state is a state after the vehicle is stopped in motion. However, this is not limiting and the diagnostic state may be a vehicle off-stream state such that health of the electric drive system may be detected while the vehicle is off-stream.

Referring to fig. 4, in another possible embodiment, after the step of S012, the control method further includes:

step S0161: judging whether the wheel transmission shaft rotates or not;

step S0162: when the wheel transmission shaft rotates, the electric drive system is controlled to be closed;

step S0163: when the wheel transmission shaft does not rotate, acquiring a vibration value of the electric drive system;

step S0141: substituting the obtained vibration value into a preset vibration value health degree data model;

step S0142: when the health degree of the electric drive system is not good, alarming is carried out;

step S017: controlling the coupling device to engage; controlling the vehicle end diagnostic state.

When the electric drive system 1 is controlled to work, the output shaft of the gear box 12 rotates, whether the wheels 4 rotate along with the output shaft of the gear box 12 or not is judged firstly, whether the wheel transmission shaft 2 rotates or not can be detected through a sensor to test whether the coupling device 3 fails or not, whether power transmission between the electric drive system 1 and the wheel transmission shaft 2 can be disconnected or not can be judged, when the coupling device 3 fails, the wheel transmission shaft 2 can rotate along with the wheel transmission shaft 2 when the electric drive system 1 works, when the wheel transmission shaft 2 rotates, the electric drive system 1 is controlled to be closed, health diagnosis of the electric drive system 1 is not carried out any more, and the coupling device 3 can be maintained or replaced. Further, when the wheel propeller shaft 2 is not rotating, indicating that the coupling device 3 is not failed, the vibration values of the mechanical components of the electric drive system 1 are continuously obtained.

Substituting the obtained vibration value into a data model of a preset vibration value in a controller for comparison analysis, wherein a plurality of vibration values and the health degree of a component corresponding to the vibration values are preset in a vibration value health degree data model, the health degree of the corresponding component in the electric drive system 1 can be obtained after the measured vibration value is substituted, when the health degree of the component of the electric drive system 1 is not good, further detection or maintenance is needed, and a user is warned through alarming. The vibration value health data model may be created using a data-driven approach to train machine learning, and then analyze and classify the substituted vibration values to determine whether the electric drive system 1 is faulty. Finally, the diagnosis state is ended after the diagnosis of the electric drive system 1 is completed, and the control coupling device 3 is re-engaged to enable the wheel drive shafts 2 to rotate with the gear box 12 of the electric drive system 1, so that the vehicle can normally travel under the drive of the electric drive system 1.

In an alternative embodiment, step S0141 may also be replaced by performing time domain signal analysis on the obtained vibration value and the preset healthy vibration value. Specifically, the obtained vibration signal and the vibration signal in the state of health of the component are subjected to time domain signal analysis, such as sheath degree, skewness, peak value, and the like, to obtain a diagnosis result. Alternatively, step S0141 may also be replaced by performing frequency domain signal analysis on the obtained vibration value and a preset healthy vibration value. Specifically, the health of the electric drive system 1 is obtained by observing abnormal frequencies, such as FFT (fast fourier transform), spectral kurtosis, etc., that appear in the frequency spectrum of the acquired vibration signal.

In summary, the coupling device 3 is arranged between the output shaft of the gear box 12 of the electric drive system 1 and the wheel transmission shaft 2, so that the coupling or decoupling between the electric drive system 1 and the wheel transmission shaft 2 can be realized, further, when the health degree of the components of the electric drive system 1 is diagnosed through the vibration sensor, the influence of tire noise, road noise and noise of other components is effectively avoided, a condition is provided for the vibration sensor to obtain a signal with a high signal-to-noise ratio, the measured vibration value of the electric drive system 1 is more accurate, and the detection result is more accurate. Further, in the control method for diagnosing the health degree of the electric drive system 1 by the vehicle, the vehicle is controlled to enter a diagnosis state, namely the coupling device 3 is controlled to be disconnected, so that the power transmission between the gear box 12 and the wheel transmission shaft 2 of the electric drive system 1 is disconnected, the electric drive system 1 is controlled to work, at the moment, the electric drive system 1 rotates independently, the wheel transmission shaft 2 does not rotate along with the gear box 12, then the vibration value of the component in the electric drive system 1 is obtained through a vibration sensor, the obtained vibration value is substituted into a vibration value health degree data model preset in a controller for comparison and analysis, and if the health degree of the component in the electric drive system 1 is not good, an alarm is given to a user. Further, in order to be able to ensure the safety of the vehicle and the periodicity of the diagnosis of the electric drive system 1, the vehicle is controlled to diagnose the electric drive system 1 when the vehicle does not diagnose the vehicle for a long time. Furthermore, after the coupling device 3 is disconnected and the electric drive system 1 is operated, the coupling device 3 is self-checked, specifically, whether the wheel transmission shaft 2 rotates along with the electric drive system 1 is judged, and when the wheel transmission shaft 2 rotates along with the gear box 12, the coupling device 3 fails, so that the safety of vehicle diagnosis is improved.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

Claims

1. A vehicle comprising an electric drive system and a wheel transmission shaft, the electric drive system being provided with a gearbox for outputting power to the wheel transmission shaft, characterised in that a coupling device is provided between an output shaft of the gearbox and the wheel transmission shaft.

2. The vehicle of claim 1, characterized in that the coupling is a friction plate clutch or a dog tooth clutch.

3. A control method of a vehicle, characterized in that the vehicle comprises an electric drive system and a wheel drive shaft, the electric drive system is provided with a gear box for outputting power to the wheel drive shaft, and a coupling device is arranged between an output shaft of the gear box and the wheel drive shaft; the control method comprises the following steps:

controlling the vehicle to enter a diagnostic state;

controlling the electric drive system to work;

acquiring a vibration value of the electric drive system;

4. The control method of a vehicle according to claim 3, wherein the step of controlling the electric drive system to operate further comprises:

and controlling the electric drive system to work at a preset speed.

5. The control method of a vehicle according to claim 3, wherein the step of "controlling the vehicle to enter a diagnostic state" further comprises:

acquiring the last diagnosis time of the vehicle;

6. The control method of a vehicle according to claim 5, wherein the step of controlling the vehicle to enter the diagnostic state when the time interval from the last diagnosis is greater than or equal to a first preset time further comprises:

7. The control method of the vehicle according to claim 3, characterized in that after the step of "controlling the electric drive system to operate", the control method further comprises:

judging whether the wheel transmission shaft rotates or not;

controlling the electric drive system to shut down when the wheel drive shaft is rotating.

8. The control method of a vehicle according to claim 3, characterized in that, after the step of "judging the health of the electric drive system based on the vibration value", the control method further comprises:

9. The control method of the vehicle according to claim 3, wherein the step of "judging the health of the electric drive system based on the vibration value" further includes:

obtaining a health of the electric drive system;

a health of the electric drive system is obtained.

10. The control method of a vehicle according to claim 7, wherein, after the step of "determining whether the wheel transmission shaft is rotated", the control method further comprises: