Control method for avoiding false triggering of vehicle TCS function and reducing vehicle speed fluctuation

Abstract

The invention discloses a control method for avoiding false triggering of a vehicle TCS function and reducing vehicle speed fluctuation, and relates to the technical field of electric vehicle control, the method comprises the steps that a vehicle MCU obtains the rotation acceleration alpha 1 of a vehicle driving wheel and a judgment parameter, and whether the vehicle is on a bumpy road surface or not is judged according to the rotation acceleration alpha 1 of the driving wheel and the judgment parameter; when the vehicle MCU judges that the vehicle is on the bumpy road surface, the TCS function of the vehicle is closed, the rotating speed of the driving wheel is adjusted according to the target rotating speed v1 of the driving wheel, and the target rotating speed v1 of the driving wheel is the rotating speed of the driving wheel at the moment before the vehicle is on the bumpy road surface. According to the control method, the TCS function can be prevented from being frequently triggered by mistake when passing through a bumpy road surface, and the smoothness and safety of vehicle driving are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle control, and in particular to a control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations. Background Art

[0002] The TCS (Traction Control System) of existing electric vehicles determines the skidding condition of the vehicle by detecting the slip ratio of the driving wheels or the change in the acceleration of the driving wheels. When the vehicle skids, the TCS function is triggered, that is, the torque applied to the driving wheels is adjusted through the torque control system to suppress skidding and improve the stability of the vehicle body.

[0003] When the vehicle passes over a speed bump or a bumpy road surface, the tires will leave the ground. Due to the existence of the driving torque, the rotational speed of the driving wheels will increase rapidly, which will cause the vehicle TCS system to misjudge that the vehicle is skidding, thereby triggering the TCS system to reduce the torque. When the vehicle lands again, at this time the torque is small and it is necessary to re-track to the target torque, resulting in the vehicle being unable to drive smoothly, with a poor experience, affecting the driving smoothness and the system life. Summary of the Invention

[0004] In view of the above problems and technical requirements, the inventor of the present invention has proposed a control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations. The technical solution of the present invention is as follows:

[0005] A control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations, comprising:

[0006] The vehicle MCU obtains the rotational acceleration α1 of the vehicle driving wheels and a judgment parameter, and determines whether the vehicle is on a bumpy road surface according to the rotational acceleration α1 of the driving wheels and the judgment parameter;

[0007] When the vehicle MCU determines that the vehicle is on a bumpy road surface, it turns off the TCS function of the vehicle and adjusts the rotational speed of the driving wheels according to the target rotational speed v1 of the driving wheels, where the target rotational speed v1 of the driving wheels is the rotational speed of the driving wheels at the previous moment when the vehicle is on a bumpy road surface.

[0008] A further technical solution thereof is that when the rotational acceleration α1 of the driving wheels is greater than the skidding acceleration threshold α th , and the judgment parameter is greater than the judgment threshold, the vehicle MCU determines that the vehicle is on a bumpy road surface.

[0009] A further technical solution thereof is that the judgment parameter includes an inertia coefficient J1, and the judgment threshold includes an inertia coefficient threshold J th ;

[0010] The inertia coefficient J1 = α / T e, where α is the rotational acceleration of the motor, and T e is the driving torque of the motor;

[0011] The inertia coefficient threshold J th is obtained by the vehicle MCU querying the inertia coefficient threshold regulation table according to the vehicle weight; the inertia coefficient threshold regulation table is used to describe the corresponding relationship between the vehicle weight and the inertia coefficient threshold J th of.

[0012] A further technical solution thereof is that the judgment parameter includes the vertical acceleration change rate Jerk1 of the vehicle's rear wheel, and the judgment threshold includes the vertical acceleration change rate threshold Jerk th ;

[0013] The vertical acceleration change rate threshold Jerk th is obtained by the vehicle MCU querying the vertical acceleration change rate threshold regulation table according to the vehicle weight;

[0014] The vertical acceleration change rate threshold regulation table is used to describe the corresponding relationship between the vehicle weight and the vertical acceleration change rate threshold Jerk th of.

[0015] A further technical solution thereof is that the judgment parameter includes the impulse change rate v of the vehicle's shock absorber I , and the judgment threshold includes the impulse change rate threshold v th .

[0016] A further technical solution thereof is that when the vehicle MCU determines that the vehicle is on a bumpy road surface, the vehicle MCU calculates the rotational speed of the driving wheel at the previous moment when the vehicle is on a bumpy road surface according to the current rotational acceleration α1 of the driving wheel of the vehicle and the current rotational speed v2 of the driving wheel;

[0017] When the vehicle MCU adjusts the rotational speed of the driving wheel according to the target rotational speed v1 of the driving wheel, it includes adjusting the rotational speed of the driving wheel when the current rotational speed v2 of the driving wheel is greater than the target rotational speed v1, so that the rotational speed of the driving wheel is equal to the target rotational speed v1.

[0018] A further technical solution thereof is to include installing a height sensor or a gyroscope on the vehicle's rear wheel to measure the height of the vehicle's rear wheel, and calculating the vertical acceleration change rate Jerk1 of the vehicle's rear wheel according to the height of the vehicle's rear wheel.

[0019] A further technical solution thereof is that in the inertia coefficient threshold regulation table, the inertia coefficient threshold J th is inversely proportional to the vehicle weight.

[0020] A further technical solution thereof is that in the vertical acceleration change rate threshold regulation table, the vertical acceleration change rate threshold v th is inversely proportional to the vehicle weight.

[0021] A further technical solution thereof is that the control method is used to execute when the vehicle has a throttle input.

[0022] The beneficial technical effects of the present invention are as follows:

[0023] According to the rotational acceleration α1 of the vehicle's driving wheels and the judgment parameter, the present invention determines whether the vehicle is on a bumpy road surface. When the vehicle is on a bumpy road surface, the TCS function is turned off to prevent the TCS function from being frequently mis-triggered when passing through a bumpy road surface. After determining that the vehicle is on a bumpy road surface, by controlling the rotational speed of the driving wheels to maintain the rotational speed of the driving wheels before the mutation, the influence caused by the wheel inertia is reduced, the vehicle speed fluctuation is decreased, the ride comfort and safety of the vehicle are improved, and the service life of the vehicle control system is prolonged. Description of the Drawings

[0024] Figure 1 It is a schematic flowchart of an embodiment of a control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuation provided by the present invention. Detailed Embodiments

[0025] The following further describes the detailed embodiments of the present invention with reference to the drawings. It can be understood that the detailed embodiments described herein are only used to explain the relevant content and are not intended to limit the present disclosure.

[0026] To solve the problem that the vehicle TCS function is frequently mis-triggered when passing through a bumpy road surface and the problem of vehicle speed fluctuation when the vehicle passes through a bumpy road surface, the present invention discloses a control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuation, including: the vehicle MCU obtains the rotational acceleration α1 of the vehicle's driving wheels and the judgment parameter, and determines whether the vehicle is on a bumpy road surface according to the rotational acceleration α1 of the driving wheels and the judgment parameter;

[0027] When the vehicle MCU determines that the vehicle is on a bumpy road surface, it turns off the TCS function of the vehicle and adjusts the rotational speed of the driving wheels according to the target rotational speed v1 of the driving wheels, where the target rotational speed v1 of the driving wheels is the rotational speed of the driving wheels at the previous moment when the vehicle is on a bumpy road surface.

[0028] The fundamental reason why the vehicle TCS function is mis-triggered when passing through a bumpy road surface is that when the driving wheels of the vehicle are lifted off the ground when passing through a bumpy road surface, the motor driving torque T e is still applied to the driving motor, and there is no friction between the tires, resulting in the rotational acceleration α1 of the driving wheels being greater than the set TCS function trigger threshold, that is, the slip acceleration threshold α th , and finally the vehicle determines that the vehicle has slipped and mis-triggers the TCS function. Therefore, the current trigger strategy of the TCS function is imperfect. The specific definition of the TCS function is consistent with the background technology and will not be elaborated here.

[0029] The present invention determines whether the vehicle is on a bumpy road surface based on the rotational acceleration α1 of the driving wheel and a judgment parameter. When it is determined that the vehicle is on a bumpy road surface, the TCS function of the vehicle is turned off, thereby avoiding the situation of false triggering of the TCS function when the vehicle is on a bumpy road surface.

[0030] After it is determined that the vehicle is on a bumpy road surface, since the vehicle MCU will turn off the TCS function and will not execute the torque control strategy, the torque applied to the motor will not be reduced, which will cause the rotational speed of the driving wheel to continue to rise rapidly after being lifted by the bumpy road surface. Due to inertia, the driving wheel will still maintain the tendency of moving forward at high speed when it lands, affecting the driving smoothness and safety of the vehicle. The above vehicle includes an electric two-wheeler.

[0031] Therefore, in order to reduce the vehicle speed fluctuation and improve the driving smoothness and safety, when the vehicle MCU determines that the vehicle is on a bumpy road surface, while turning off the TCS function of the vehicle, it is also necessary to adjust the rotational speed of the driving wheel when the rotational speed of the driving wheel is greater than the target rotational speed v1 of the driving wheel. The target rotational speed v1 of the driving wheel is the rotational speed of the driving wheel at the previous moment when the vehicle is on the bumpy road surface. The rotational speed of the driving wheel at the previous moment when the vehicle is on the bumpy road surface, that is, the rotational speed before the rotational speed suddenly changes due to the driving wheel being lifted by the bumpy road surface. The specific method of determining whether the vehicle is on a bumpy road surface based on the rotational acceleration α1 of the driving wheel and the judgment parameter can be referred to the following description.

[0032] Further, when the vehicle MCU determines that the vehicle is on a bumpy road surface, the vehicle MCU calculates the rotational speed of the driving wheel at the previous moment when the vehicle is on the bumpy road surface based on the current rotational acceleration α1 of the driving wheel of the vehicle and the current rotational speed v2 of the driving wheel.

[0033] Specifically, from the above description, it can be seen that the rotational speed of the driving wheel will increase when the driving wheel is lifted by the bumpy road surface, that is, v2 is usually greater than v1. Therefore, the rotational speed of the driving wheel at the previous moment when the vehicle is on the bumpy road surface, that is, the target rotational speed v1 = v2 - α1Δt, where Δt is the time difference between the current moment and the previous moment when the vehicle is on the bumpy road surface. When the vehicle MCU adjusts the rotational speed of the driving wheel according to the target rotational speed v1, it includes adjusting the rotational speed of the driving wheel when the current rotational speed v2 of the driving wheel is greater than the target rotational speed v1, so that the rotational speed of the driving wheel is equal to the target rotational speed v1, thereby reducing the acceleration feeling caused when the wheel lands after being lifted and vacated by the bumpy road surface, avoiding danger and optimizing the driving experience.

[0034] Generally, a vehicle control system controls the rotational speed of a driving wheel through a speed limit loop. Specifically, when the driving wheel is lifted over a bumpy road surface, the vehicle MCU determines that the vehicle is on a bumpy road surface. The vehicle control system detects that v2 > v1, and the speed limit loop outputs a negative torque to the motor through a speed limit regulator, causing the rotational speed of the driving wheel to decrease until the rotational speed of the driving wheel equals the target rotational speed v1 of the driving wheel. The specific forms of the speed limit loop and the speed limit regulator may be consistent with the prior art.

[0035] Further, the rotational acceleration α1 of the driving wheel is greater than the slip acceleration threshold α th , and when the judgment parameter is greater than the judgment threshold, the vehicle MCU determines that the vehicle is on a bumpy road surface. The rotational acceleration α1 of the driving wheel is greater than the slip acceleration threshold α th , and when the judgment parameter is not greater than the judgment threshold, the vehicle MCU determines that the vehicle has slipped and normally triggers the TCS function.

[0036] Optionally, the judgment parameter may be the inertia coefficient J1, and the judgment threshold may correspond to the inertia coefficient threshold J th . The inertia coefficient J1 = α / T e , where α is the rotational acceleration of the motor, and the T e is the motor drive torque. According to Newton's laws of motion, when the motor is running, it satisfies: T e - T L = Jα, where T L is the load torque and J is the motor inertia. When the driving wheel of the vehicle is lifted over a bumpy road surface, the load torque T L is approximately 0, so the ratio of the rotational acceleration α of the motor and the motor drive torque T e can be calculated and denoted as the inertia coefficient J1.

[0037] In an embodiment of the present invention, when the rotational acceleration α1 of the driving wheel is greater than the slip acceleration threshold α th and the inertia coefficient J1 is greater than the inertia coefficient threshold J th , it is determined that the vehicle is on a bumpy road surface, and the vehicle MCU turns off the TCS function. When the vehicle is driving on a slippery road surface or a bumpy road surface, it will cause the rotational acceleration α1 of the driving wheel to increase abnormally. However, when the driving wheel is lifted over a bumpy road surface, the driving wheel is completely free from friction, and the rotational acceleration α1 of the driving wheel when the vehicle is driving on a bumpy road surface will be much greater than the rotational acceleration α1 of the driving wheel when the vehicle is driving on a slippery road surface. Therefore, when the vehicle is driving on a bumpy road surface, the inertia coefficient J1 will be greater than the inertia coefficient threshold J th , the vehicle MCU determines that the vehicle is on a bumpy road surface, and the vehicle MCU forcibly turns off the TCS function. Therefore, the TCS function will not be mis-triggered due to α1 > α th when the vehicle is driving on a bumpy road surface.

[0038] For extremely slippery road surfaces or extremely light vehicles, assume that when the vehicle is driving on a wet and bumpy road surface, the rotational acceleration α1 of the driving wheel is similar. When the rotational acceleration α1 of the driving wheel is similar, since the motor driving torque T required when the driving wheel is lifted on the bumpy road surface e is much smaller than the motor driving torque T required under the wet road surface e , so the inertia coefficient J1 of the vehicle when driving on the bumpy road surface will be greater than the inertia coefficient threshold J th . The vehicle MCU determines that the vehicle is on a bumpy road surface, and the vehicle MCU forcibly turns off the TCS function. Therefore, the TCS function will not be accidentally triggered due to α1>α when the vehicle is driving on the bumpy road surface th .

[0039] The inertia coefficient threshold J th is obtained by the vehicle MCU querying the inertia coefficient threshold regulation table according to the vehicle weight. The inertia coefficient threshold regulation table is used to describe the corresponding relationship between the vehicle weight and the inertia coefficient threshold J th , and it is a two-dimensional table of the preset corresponding relationship between the vehicle weight and the inertia coefficient threshold J th . In the inertia coefficient threshold regulation table, the inertia coefficient threshold J th is inversely proportional to the vehicle weight. The corresponding relationships between different vehicle weights and the inertia coefficient threshold J th in the inertia coefficient threshold regulation table can be set according to the actual situation

[0040] In another embodiment of the present invention, the judgment parameter is the vertical acceleration change rate Jerk1 of the vehicle's rear wheels, and the judgment threshold is the vertical acceleration change rate threshold Jerk th ; similarly to the above embodiment, when the rotational acceleration α1 of the driving wheel is greater than the slip acceleration threshold α th , and the vertical acceleration change rate Jerk1 of the vehicle's rear wheels is greater than the vertical acceleration change rate threshold Jerk th , the vehicle MCU determines that the vehicle is on a bumpy road surface, and the vehicle MCU turns off the TCS function. It can be understood that the vertical acceleration change rate Jerk1 of the vehicle's rear wheels when the vehicle is driving on the bumpy road surface will be greater than the vertical acceleration change rate Jerk1 of the vehicle's rear wheels when the vehicle is driving on the wet road surface. Therefore, the vertical acceleration change rate Jerk1 of the vehicle's rear wheels when the vehicle is driving on the bumpy road surface will be greater than the vertical acceleration change rate threshold Jerk th . The vehicle MCU determines that the vehicle is on a bumpy road surface and forcibly turns off the TCS function. Therefore, the TCS function will not be accidentally triggered due to α1>α when the vehicle is driving on the bumpy road surface thThe TCS function is accidentally triggered. During specific implementation, a height sensor or a gyroscope can be installed on the rear wheels of the vehicle to measure the height of the rear wheels of the vehicle, and the change rate of the vertical acceleration Jerk1 of the rear wheels of the vehicle can be calculated based on the height of the rear wheels of the vehicle. The specific method for calculating the change rate of the vertical acceleration Jerk1 of the rear wheels of the vehicle based on the height of the rear wheels of the vehicle is consistent with the prior art.

[0041] The vertical acceleration change rate threshold Jerk th is obtained by the vehicle MCU querying the vertical acceleration change rate threshold regulation table according to the vehicle weight; the vertical acceleration change rate threshold regulation table is used to describe the corresponding relationship between the vehicle weight and the vertical acceleration change rate threshold Jerk th and is a two-dimensional table of the preset corresponding relationship between the vehicle weight and the vertical acceleration change rate threshold Jerk th In the vertical acceleration change rate threshold regulation table, the vertical acceleration change rate threshold v th is inversely proportional to the vehicle weight. The corresponding relationships between different vehicle weights and the vertical acceleration change rate threshold v th in the vertical acceleration change rate threshold regulation table can be set according to the actual situation.

[0042] In another embodiment of the present invention, the judgment parameter is the impulse change rate v I of the vehicle shock absorber, and the judgment threshold is the impulse change rate threshold v th . During specific implementation, an impulse sensor can be installed on the shock absorber at the rear of the vehicle, and the impulse change rate v I of the vehicle shock absorber can be calculated by measuring the impulse of the shock absorber. The specific method for calculating the impulse change rate v I of the vehicle shock absorber through the impulse of the shock absorber is consistent with the prior art. The impulse change rate threshold v th can be an empirical value. It can be understood that when the vehicle is driving on a bumpy road surface, the impulse change rate v I of the vehicle shock absorber will be greater than the impulse change rate v I of the vehicle shock absorber when the vehicle is driving on a slippery road surface. Therefore, when the vehicle is driving on a bumpy road surface, the impulse change rate v I of the vehicle shock absorber will be greater than the impulse change rate threshold v th , and the vehicle MCU will determine that the vehicle is on a bumpy road surface and forcefully turn off the TCS function. Therefore, the TCS function will not be accidentally triggered due to α1>α th when the vehicle is driving on a bumpy road surface. It should be noted that during specific implementation, the above control method needs to be executed when the vehicle has a throttle input. For an electric two-wheeler, it means that it is executed when the throttle is twisted or stepped on. When the vehicle has no throttle input, the vehicle MCU does not execute the above control method.

[0043] In summary, the present invention determines whether the vehicle is on a bumpy road surface based on the vehicle's drive wheel rotational acceleration α1 and a judgment parameter, and disables the TCS function when the vehicle is on a bumpy road surface, effectively preventing frequent false triggering of the TCS function when traversing bumpy roads. Furthermore, after determining that the vehicle is on a bumpy road surface, the present invention also controls the drive wheel speed to maintain the speed before the sudden change, thereby mitigating the effects of wheel inertia, reducing vehicle speed fluctuations, improving driving smoothness and safety, and extending the service life of the vehicle control system.

[0044] Reference to the term "one embodiment" or the like means that a specific feature or characteristic described in conjunction with that embodiment is included in at least one embodiment of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment. Moreover, the specific features or characteristics described may be combined in any suitable manner in any one or more embodiments. Furthermore, those skilled in the art may combine and associate the different embodiments and features of the different embodiments described in this specification without conflicting opinions.

[0045] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment. It is understood that other improvements and variations directly derived or imagined by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the scope of protection of the present invention.

Claims

1. A control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations, characterized in that, Including: The vehicle MCU obtains the rotational acceleration α1 of the vehicle's driving wheels and the judgment parameter, and determines whether the vehicle is on a bumpy road surface based on the rotational acceleration α1 of the driving wheels and the judgment parameter; When the vehicle MCU determines that the vehicle is on a bumpy road surface, it turns off the TCS function of the vehicle and adjusts the rotational speed of the driving wheels according to the target rotational speed v1 of the driving wheels, where the target rotational speed v1 of the driving wheels is the rotational speed of the driving wheels at the previous moment when the vehicle is on a bumpy road surface.

2. The control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations according to claim 1, characterized in that, The rotational acceleration α1 of the drive wheel is greater than the slip acceleration threshold α th , and when the judgment parameter is greater than the judgment threshold, the vehicle MCU determines that the vehicle is on a bumpy road surface.

3. The control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations according to claim 2, wherein The judgment parameter includes an inertia coefficient J1, and the judgment threshold includes an inertia coefficient threshold J th ; The inertia coefficient J1 = α / T e , where α is the rotational acceleration of the motor, and T e is the driving torque of the motor; The inertia coefficient threshold J th is obtained by the vehicle MCU querying the inertia coefficient threshold regulation table according to the vehicle weight; the inertia coefficient threshold regulation table is used to describe the corresponding relationship between the vehicle weight and the inertia coefficient threshold J th of.

4. The control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuation according to claim 2, characterized in that, The determination parameter includes the vertical acceleration change rate Jerk1 of the vehicle's rear wheels, and the determination threshold includes the vertical acceleration change rate threshold Jerk th ; The vertical acceleration change rate threshold Jerk th is obtained by the vehicle MCU querying the vertical acceleration change rate threshold regulation table according to the vehicle weight; The vertical acceleration change rate threshold regulation table is used to describe the corresponding relationship between vehicle weight and the vertical acceleration change rate threshold Jerk th of.

5. The control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations according to claim 2, wherein The judgment parameter includes the impulse change rate v of the vehicle shock absorber I , and the judgment threshold includes the impulse change rate threshold v th .

6. The control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations according to claim 1, wherein When the vehicle MCU determines that the vehicle is on a bumpy road surface, the vehicle MCU calculates the rotational speed of the driving wheels at the previous moment when the vehicle is on a bumpy road surface based on the current rotational acceleration α1 of the vehicle's driving wheels and the current rotational speed v2 of the driving wheels; When the vehicle MCU adjusts the rotational speed of the driving wheels according to the target rotational speed v1 of the driving wheels, it includes adjusting the rotational speed of the driving wheels when the current rotational speed v2 of the driving wheels is greater than the target rotational speed v1 of the driving wheels, so that the rotational speed of the driving wheels is equal to the target rotational speed v1.

7. The control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations according to claim 4, characterized in that, Including installing a height sensor or a gyroscope on the vehicle's rear wheels to measure the height of the vehicle's rear wheels, and calculating the vertical acceleration change rate Jerk1 of the vehicle's rear wheels based on the height of the vehicle's rear wheels.

8. The control method for avoiding false triggering of the vehicle TCS function and reducing vehicle speed fluctuation according to claim 3, characterized in that, In the inertia coefficient threshold regulation table, the inertia coefficient threshold J th is inversely proportional to the vehicle weight.

9. The control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuation according to claim 4, characterized in that, In the vertical acceleration change rate threshold regulation table, the vertical acceleration change rate threshold v th is inversely proportional to the vehicle weight.

10. The control method for avoiding mis-triggering of the vehicle TCS function and reducing vehicle speed fluctuations according to any one of claims 1-9, characterized in that, The control method is used to execute when the vehicle has a throttle input.

Images