CN117962638A

CN117962638A - Vehicle control method, controller and vehicle

Info

Publication number: CN117962638A
Application number: CN202410268804.3A
Authority: CN
Inventors: 周志军; 陆国祥; 朱小锋; 周彩锋; 高翔
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2024-03-06
Filing date: 2024-03-06
Publication date: 2024-05-03

Abstract

The disclosure relates to a vehicle control method, a controller and a vehicle, and relates to the technical field of vehicles. Comprising the following steps: identifying a driving state of the vehicle under the condition that the vehicle is determined to be in a stationary state, hydraulic braking force is applied to wheels, and a target motor is operated normally; the hydraulic braking force is a braking force provided by brake fluid; when the driving state is a starting state, switching the hydraulic braking force applied to the wheels to a motor braking force; the motor braking force is a braking force provided by the target motor; in the case where the driving force of the vehicle is greater than the running resistance of the vehicle, the motor braking force applied to the wheels is offloaded. By using the vehicle control method provided by the disclosure, the braking noise of the vehicle during hill start can be solved from the source.

Description

Vehicle control method, controller and vehicle

Technical Field

The disclosure relates to the technical field of vehicles, and in particular relates to a vehicle control method, a controller and a vehicle.

Background

An automobile is a vehicle that transports passengers or cargo, and is generally composed of an engine, a transmission system, a chassis, a body, and other components, and is capable of traveling on a road.

With the increasing standard of living, the comfort requirements of people on vehicles are gradually improved, however, the vehicles usually generate larger noise when starting, so that the use experience of users is reduced.

Disclosure of Invention

An object of the present disclosure is to provide a vehicle control method, a controller, and a vehicle.

In order to achieve the above object, the present disclosure provides a vehicle control method including:

identifying a driving state of the vehicle under the condition that the vehicle is determined to be in a stationary state, hydraulic braking force is applied to wheels, and a target motor is operated normally; the hydraulic braking force is a braking force provided by brake fluid;

When the driving state is a starting state, switching the hydraulic braking force applied to the wheels to a motor braking force; the motor braking force is a braking force provided by the target motor;

in the case where the driving force of the vehicle is greater than the running resistance of the vehicle, the motor braking force applied to the wheels is offloaded.

Optionally, the wheel is a rear wheel of the vehicle; the switching of the hydraulic braking force applied to the wheels to the motor braking force when the driving state is a start state includes:

When the driving state is a starting state, the hydraulic braking force applied to the rear wheels is switched to the motor braking force.

Optionally, the driving state of the vehicle includes a vehicle gear, an accelerator opening and a state of an electronic parking brake; the identifying a driving state of the vehicle in a case where it is determined that the vehicle is in a stationary state, hydraulic braking force is applied to wheels, and a target motor is operating normally includes:

Under the condition that the vehicle is in a static state, hydraulic braking force is applied to wheels, and a target motor runs normally, identifying the gear of the vehicle, the opening degree of an accelerator and the state of the electronic parking brake;

and determining that the driving state is a starting state under the condition that the vehicle gear is a driving gear, the accelerator opening is larger than a preset opening and the state of the electronic parking brake is released.

Optionally, the switching the hydraulic braking force applied to the wheels to the motor braking force in the case where the driving state is a start state includes:

When the driving state is a start state and the motor braking force is greater than the hydraulic braking force, the hydraulic braking force applied to the wheels is switched to the motor braking force.

And when the driving state is a starting state and the gradient of the slope on which the vehicle is positioned is larger than the preset gradient, switching the hydraulic braking force applied to the wheels to the motor braking force.

Optionally, the method further comprises:

obtaining the motor braking force according to the residual electric quantity of the vehicle and the environmental temperature of the vehicle;

and applying the motor braking force to the wheels to control the vehicle to park.

Optionally, the obtaining the motor braking force according to the remaining power of the vehicle and the ambient temperature of the vehicle includes:

and taking the residual electric quantity and the ambient temperature as input parameters of a first PID controller, and taking the stationary state of the vehicle as a target to obtain the motor braking force.

Optionally, the unloading the motor braking force applied to the wheels in a case where the driving force of the vehicle is greater than the running resistance of the vehicle includes:

Unloading the motor braking force applied to the wheels according to the driving force of the vehicle and the gradient of the ramp on which the vehicle is positioned; the driving force of the vehicle is inversely proportional to the motor braking force.

Optionally, the unloading the motor braking force applied to the wheels according to the driving force of the vehicle and the gradient of the slope on which the vehicle is located includes:

And taking the driving force and the slope gradient as input parameters of a second PID controller, and taking the vehicle as a stationary state as a target to obtain a target motor braking force after the motor braking force on the wheels is unloaded.

Optionally, the method further comprises:

Controlling the target motor not to output a motor braking force in the presence of at least one of the following conditions:

the speed of the vehicle is larger than the preset speed, the motor braking force is smaller than the hydraulic braking force, the state of the electronic parking brake of the vehicle is unreleased, and the target motor fault and the vehicle gear are parking gears.

In order to achieve the above object, the present disclosure provides a controller for executing the above-described vehicle control method.

In order to achieve the above object, the present disclosure provides a vehicle on which the controller described above is disposed.

Through the technical scheme, when the driving state of the vehicle is identified as the starting state, if the hydraulic braking force is still applied to the wheels, the wheels can receive the hydraulic braking force and the motor driving force at the same time, and braking noise is generated; in the embodiment of the disclosure, when the driving state of the vehicle is identified as the starting state, the hydraulic braking force applied to the wheels is replaced by the motor braking force, and since the target motor can only provide the motor driving force or the motor braking force at the same time, the motor driving force cannot be provided for the wheels at the same time after the target motor provides the motor braking force for the wheels, and only the motor braking force is applied to the wheels at the moment, thereby avoiding braking noise caused by the braking force and the motor driving force at the same time and fundamentally solving the occurrence of the braking noise.

Additional features and advantages of the present disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification, illustrate the disclosure and together with the description serve to explain, but do not limit the disclosure. In the drawings:

Fig. 1 is a flowchart illustrating steps of a vehicle control method according to an exemplary embodiment of the present disclosure.

Fig. 2 is a logic diagram of a method of adjusting hydraulic braking force according to an exemplary embodiment of the present disclosure.

Fig. 3 is a logic diagram of a method of adjusting hydraulic braking force according to an exemplary embodiment of the present disclosure.

Fig. 4 is a schematic diagram of a target slope employed when unloading motor braking force according to an exemplary embodiment of the present disclosure.

Fig. 5 is a logic diagram of a vehicle control method according to an exemplary embodiment of the present disclosure.

Fig. 6 is a diagram illustrating various states of a vehicle during hill start according to an exemplary embodiment of the present disclosure.

Fig. 7 is a system architecture diagram for a vehicle parking initiation according to an exemplary embodiment of the present disclosure.

Fig. 8 is a signal interaction schematic diagram of a vehicle according to an exemplary embodiment of the present disclosure when the vehicle is parked and started.

Fig. 9 is a block diagram of a vehicle control apparatus according to an exemplary embodiment of the present disclosure.

Detailed Description

Specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the disclosure, are not intended to limit the disclosure.

At present, the vehicle generally can send great noise when starting, leads to the user to use and experience to reduce, in order to reduce the noise that the vehicle started and sent, can adopt following scheme:

In the scheme a, referring to fig. 2, a vibration time domain signal generated when a vehicle vibrates is acquired through an acceleration sensor, and a sound time domain signal generated when the vehicle vibrates is detected through a microphone; and performing Fourier transform processing on the vibration time domain signal and the sound time domain signal, comparing the processed signals with a preset decibel threshold value respectively, judging whether coupling frequency band noise exists or not, and if the coupling frequency band noise exists, adjusting hydraulic braking force so as to reduce the vibration noise.

In the scheme, the braking state information of the vehicle is obtained according to the vibration time domain signal and the sound time domain signal, and the vehicle is controlled to reduce the braking force, so that vibration and noise caused by large braking force are reduced, and the noise influence is reduced.

In the scheme B, referring to fig. 3, under the condition that a vehicle unlocking signal is received, whether the friction plate needs to be heated is determined, and if the temperature of the friction plate is less than a heating threshold, the friction plate is heated by a first heating power; and if the temperature of the friction plate is greater than the heating threshold, heating the friction plate with the second heating power.

In this scheme, because the friction disc can produce the braking noise under the lower circumstances of temperature, the friction disc contacts with the brake disc, so can adopt different heating power to heat the friction disc to avoid the friction disc because of low temperature environment hardness grow, the easy problem that takes place of the braking noise that leads to, thereby reduced the influence of braking noise.

However, in the above-described embodiments a and B, the hydraulic braking is used to brake the wheels, and the principle of the hydraulic braking is as follows: the vehicle generates braking force by controlling the flow of brake fluid, the braking force is applied to the friction plate through the wheel axle of the vehicle, the friction plate clamps the brake disc after receiving the braking force, and the friction plate and the brake disc mutually rub to absorb the kinetic energy of the vehicle, so that the vehicle is decelerated to a stop.

In the process of vehicle hill start, if the hydraulic braking force is directly released and then the vehicle is driven to advance, the vehicle can lose the parking force suddenly and then obtain the advancing force, so that the vehicle can advance suddenly after slipping, and bad experience is brought to a user. Therefore, during the hill start of the vehicle, the driving force of the vehicle is controlled to be increased first, and when the driving force is increased to be larger than the running resistance of the vehicle, the hydraulic braking force is released, so that even if the hydraulic braking force is released, the driving force is enough to support the vehicle not to back, and the vehicle does not slip.

Although avoiding the phenomenon of sliding, the brake disc can not only be subjected to the braking force of the friction plate in the process of hill start, but also be subjected to the driving force of the motor, so that the stick-slip effect occurs, and the braking noise of the vehicle is larger. Therefore, although the above-mentioned solutions a and B can reduce the braking noise, the braking noise cannot be avoided fundamentally, which also results in a reduced user experience.

Based on this, the present disclosure proposes a vehicle control method that is executed by a controller, as shown with reference to fig. 1, the method including the following steps.

In step S11, in the case where it is determined that the vehicle is in a stationary state, hydraulic braking force is applied to wheels, and the target motor is operating normally, the driving state of the vehicle is identified.

The vehicle being in a stationary state may be that a vehicle speed of the vehicle is less than a preset vehicle speed, taking the preset vehicle speed as an example, and when the vehicle speed is less than 3km/h, the vehicle is considered to be in a stationary state.

The hydraulic braking force is a braking force applied to the friction plate and the brake disc by a hydraulic pressure of a brake fluid in a vehicle brake system, and is used to brake the wheels. Referring to fig. 5, it may be determined that a hydraulic braking force is applied to wheels in a case where an automatic parking function of the vehicle has been activated.

The front axle motor drives the front wheels of the vehicle to rotate; the target motor is a motor of a rear axle of the vehicle, and can be used as a driving motor of rear wheels of the vehicle or a parking motor, the driving motor drives the rear wheels of the vehicle to advance, and the parking motor provides motor braking force for the rear wheels of the vehicle.

As can be appreciated, in the related art, when the vehicle is running normally, the target motor drives the rear wheels of the vehicle to advance; when the vehicle starts on a hill, the front axle motor applies driving force to the front wheels of the vehicle, the target motor applies driving force to the brake disc so that the wheels have forward running power, and the hydraulic braking force applies braking force to the brake disc so as to prevent the vehicle from sliding down, and the driving force and the braking force are simultaneously applied to the brake disc so as to generate braking noise.

In the embodiment of the disclosure, when the vehicle runs normally, the target motor drives the rear wheels of the vehicle to advance; when the vehicle starts on a hill, the front axle motor drives the front wheels of the vehicle to apply driving force, hydraulic braking force is not applied to the brake disc of the rear axle any more, driving force applied to the brake disc by the target motor of the rear axle is converted into braking force, and braking force is applied to the brake disc at the same time, so that braking noise generated by simultaneously applying driving force and braking force to the brake disc is avoided.

The driving state of the vehicle represents the user's driving intention, for example, when the driving state of the vehicle is a start state, it represents that the user's driving intention is start.

When the vehicle is determined to be in a stationary state and hydraulic braking force is applied to the wheels, the vehicle is stationary, and the vehicle is parked by means of hydraulic braking at the moment; under the condition that the target motor normally operates, the target motor representing the rear axle of the vehicle can be normally used, and motor braking force can be provided for the brake disc. Therefore, in the case where the vehicle is parked by means of hydraulic braking and the vehicle is able to provide motor braking force to the brake disc, the driving state of the vehicle can be recognized, thereby judging whether the user has a start intention.

Of course, in the event of a failure of the target motor, the representative target motor cannot supply the motor braking force to the brake disc, and therefore the hydraulic braking force applied to the wheels can be prevented from being switched.

In addition, when the non-target motor on the vehicle fails, the hydraulic braking force applied to the wheels may not be switched to the motor braking force, and when the front axle motor fails and the target motor of the rear axle is still switched to the motor braking force from the motor driving force, the vehicle loses the forward driving force, and the vehicle does not travel forward at this time, so that in this case, the target motor of the rear axle is controlled to maintain the motor driving force, and the vehicle can be ensured to travel forward.

In step S12, when the driving state is a start state, the hydraulic braking force applied to the wheels is switched to the motor braking force.

The process of switching the hydraulic braking force to the motor braking force includes: the hydraulic braking force is released, and the motor driving force of the target motor of the rear axle is converted into motor braking force.

The hydraulic braking force applied to the wheels is actually the hydraulic braking force applied to the brake disc, and therefore switching the hydraulic braking force applied to the wheels to the motor braking force is actually switching the hydraulic braking force applied to the brake disc to the motor braking force.

In the embodiment of the present disclosure, the wheels are rear wheels, and switching the hydraulic braking force applied to the wheels to the motor braking force is switching the hydraulic braking force applied to the rear wheels of the vehicle to the motor braking force. In this scenario, the front wheels of the vehicle are subjected to the driving force of the front axle motor, the rear wheels of the vehicle are subjected to the motor braking force of the target motor of the rear axle, and the motor braking force replaces the hydraulic braking force to provide a temporary braking function for the vehicle.

When the driving state is a starting state, it is indicated that the user has a starting intention, and when the vehicle starts, the vehicle is subjected to both the hydraulic braking force and the driving force of the target motor, and a stick-slip effect is generated, so that braking noise is generated. To avoid braking noise generated by the brake disc, embodiments of the present disclosure switch hydraulic braking force applied to the wheels to motor braking force when it is recognized that the user has a start intention.

For example, when it is recognized that the user has a start intention, the hydraulic braking force applied to the wheels is released, and the motor driving force applied to the wheels by the target motor is converted into the motor braking force, so that the acting force applied to the wheels is only the motor braking force, thereby avoiding the generation of the stick-slip effect, and enabling the motor braking force to provide a temporary parking function for the vehicle.

It will be appreciated that the vehicle determined in the embodiment of the present disclosure is in a state of being started, which is a state before the user has a start intention, but the vehicle is not yet started, and may be regarded as a state in which the vehicle is ready to start by stepping on the accelerator in fig. 6. When the vehicle is in a starting state, the vehicle is stationary, and after the hydraulic braking force is switched to the motor braking force and the starting is successful, the vehicle is switched from the stationary state to the running state.

In step S13, in the case where the driving force of the vehicle is greater than the running resistance of the vehicle, the motor braking force applied to the wheels is offloaded.

The driving force of the vehicle refers to the driving force provided by the front axle motor of the vehicle, which drives the front wheels forward, and the target motor of the rear axle provides braking force for the rear wheels of the vehicle.

The running resistance of the vehicle means motor braking force, friction force, wind force, resistance caused by gravity of the vehicle, and the like, which cause the vehicle to slip backward on the slope when the vehicle does not have forward driving force.

Unloading the motor braking force applied to the wheels does not directly release the motor braking force on the wheels, but rather means gradually reducing the motor braking force applied to the wheels. For example, the motor braking force is gradually decreased while the vehicle driving force is gradually increased until the motor braking force is completely unloaded.

In the case where the driving force of the vehicle is greater than the running resistance of the vehicle, it is indicated that the driving force of the vehicle is sufficient to advance the vehicle without slipping the vehicle, at which time the motor braking force applied to the wheels can be offloaded.

Referring to fig. 6, the arrow on the left side of the drive wheel represents the braking torque and the arrow on the right side of the drive wheel represents the driving torque. When the automatic parking function of the vehicle is activated, the vehicle provides braking torque through hydraulic braking force; when the user steps on the accelerator, recognizing that the user has a starting intention, switching the hydraulic braking force into a motor braking force, wherein the motor braking force is larger than the driving force; when the vehicle is starting, the driving force of the vehicle is gradually increased, the braking force of the motor is gradually reduced, and the vehicle is still in a static state; after the vehicle starts successfully, the motor braking force of the vehicle is completely unloaded, and the driving force of the vehicle drives the vehicle to advance.

According to the technical scheme, when the fact that the vehicle is parked through the hydraulic braking force and the target motor normally runs is determined, the driving state of the vehicle is identified, if the driving state is a starting state, the fact that the user has a starting intention is determined, and at the moment, the hydraulic braking force applied to the vehicle can be replaced by the motor braking force; and under the condition that the driving force of the vehicle is larger than the running resistance of the vehicle, the vehicle is determined to have a forward trend, and the motor braking force output by the target motor is controlled to be continuously reduced, so that the vehicle is ensured to smoothly move forward.

In the process, when the driving state of the vehicle is identified as the starting state, if the hydraulic braking force is still applied to the wheels, the wheels are subjected to the hydraulic braking force and the motor driving force at the same time, and braking noise occurs; in the embodiment of the disclosure, when the driving state of the vehicle is identified as the starting state, the hydraulic braking force applied to the wheels is replaced by the motor braking force, and since the target motor can only provide the motor driving force or the motor braking force at the same time, the motor driving force cannot be provided for the wheels at the same time after the target motor provides the motor braking force for the wheels, and only the motor braking force is applied to the wheels at the moment, thereby avoiding braking noise caused by the braking force and the motor driving force at the same time and fundamentally solving the occurrence of the braking noise.

In the second aspect, compared with the method of directly adopting the target motor to brake the rear wheels of the vehicle and completely discarding the hydraulic braking mode to brake the rear wheels of the vehicle, when the target motor brakes the rear wheels of the vehicle for a long time, the target motor can be overheated, and the target motor is extremely fragile. Therefore, in the embodiment of the disclosure, in the process of hill start, the hydraulic braking force is replaced by the motor braking force provided by the target motor, so that the motor braking force temporarily replaces the hydraulic braking force to realize the braking function, and the duration of the motor braking force is relatively short, so that the target motor is not overheated and damaged.

In the third aspect, since the embodiments of the present disclosure solve the problem of braking noise without adding additional components, but with program improvement based on components of the vehicle itself, no additional production cost is generated.

A specific embodiment related to the above step S11 is described below, which is used to explain how to identify whether the driving state of the vehicle is a starting state according to the gear position of the vehicle, the accelerator opening degree, and the state of the electronic parking brake.

(1) And under the condition that the vehicle is in a static state, hydraulic braking force is applied to wheels, and a target motor normally operates, identifying the vehicle gear, the accelerator opening and the state of the electronic parking brake.

In the case where it is determined that the vehicle is in a stationary state, hydraulic braking force is applied to wheels, and the target motor is operating normally, it is determined that the vehicle is braked by the hydraulic braking force in a stopped state, and the target motor is able to provide motor braking force. In this case, whether the user has a start intention may be determined by the vehicle gear, the accelerator opening degree, and the state of the electronic parking brake.

The vehicle gear comprises a driving gear and a parking gear, wherein the driving gear comprises a driving gear (D gear) and a reverse gear (R gear); the parking gear comprises a parking gear (P gear) and a neutral gear (N gear).

The accelerator opening is used for reflecting the depth of the accelerator depression, and the larger the accelerator opening is, the higher the acceleration requirement of a representative user is.

The electronic parking brake is an electronic parking brake system (ELECTRICAL PARK brake, EPB), the electronic parking brake replaces a traditional hand brake to realize braking, and the electronic parking brake controls the parking brake through an electronic circuit to realize parking.

(2) And determining that the driving state is a starting state under the condition that the vehicle gear is a driving gear, the accelerator opening is larger than a preset opening and the state of the electronic parking brake is released.

When the vehicle gear is a driving gear, representing that the vehicle is in a running state; when the accelerator opening is larger than the preset opening, the vehicle is in a starting state, and when the accelerator opening is smaller than the preset opening, the vehicle is in a non-starting state; in the case where the electronic parking brake is released, it represents that the vehicle is in an out-of-park state.

Therefore, if the electronic parking brake releases the vehicle and the vehicle is not parked any more, and the user adjusts the vehicle gear to the driving gear and steps on the accelerator, a start intention exists on behalf of the user, and at this time, it can be determined that the driving state of the vehicle is the start state.

In one possible mode, in the case where the driving state is a starting state and the motor braking force is greater than the hydraulic braking force, the hydraulic braking force applied to the wheels is switched to the motor braking force.

Because the hydraulic braking force is adopted to brake the brake disc before the motor braking force is not used for braking the brake disc, the vehicle can just stay on the ramp without sliding down when the hydraulic braking force brakes the brake disc. If the motor braking force provided by the target motor cannot be larger than the hydraulic braking force, the vehicle can slide on the ramp even if the target motor outputs the motor braking force to brake the brake disc, so that the use experience of a user is reduced.

Therefore, in order to avoid the vehicle from sliding, when the motor braking force is larger than the hydraulic braking force, the target motor can be controlled to output the motor braking force to brake the vehicle when the motor braking force provided by the target motor is determined to be enough to support the vehicle to park on the slope, so that the vehicle is prevented from sliding.

In one possible manner, referring to fig. 5, in the case where the driving state is a start state and the slope gradient of the vehicle is greater than a preset gradient, the hydraulic braking force applied to the wheels is switched to the motor braking force.

When a vehicle starts on a flat road, since the vehicle directly releases hydraulic braking force to drive the vehicle forward on the flat road and does not cause the vehicle to roll, the logic of starting the vehicle on the flat road is generally: the hydraulic braking force is directly released, and driving force is respectively applied to the front wheels and the rear wheels through the front shaft motor and the rear shaft motor to drive the vehicle to advance.

In the process of starting on a flat road surface, the brake disc only receives hydraulic braking force or motor driving force at the same time and does not receive the hydraulic braking force and the motor driving force at the same time, so that large braking noise cannot be generated, and if the hydraulic braking force applied to the wheels is switched to the motor braking force to reduce the noise, the benefits are not brought, and the electric quantity resources of the vehicle are wasted.

Therefore, the embodiment of the present disclosure switches the hydraulic braking force applied to the wheels to the motor braking force in the case where the gradient of the hill is greater than the preset gradient.

When the vehicle starts on a slope, if the driving force is applied after the hydraulic braking force is released, the vehicle slides, because the vehicle loses power in the period between the release of the hydraulic braking force and the application of the driving force, and thus the vehicle slides. Thus, on a grade, the vehicle launch logic is typically: the driving force is controlled to increase first, and when the driving force is increased to be larger than the running resistance of the vehicle, the driving force is enough to drive the vehicle to reside on the slope, and then the hydraulic braking force is released, so that the sliding of the vehicle is avoided.

However, in the process of starting on the road surface of the slope, the brake disc receives hydraulic braking force and motor driving force at the same time, so that large braking noise is generated. Therefore, when the gradient of the slope on which the vehicle is positioned is larger than the preset gradient, the hydraulic braking force applied to the wheels is switched to the motor braking force, so that the acting force applied to the vehicle in the process of hill start is only the motor braking force, and the braking noise is reduced.

For example, taking a case where the vehicle gear is a driving gear and the slope gradient is greater than the preset gradient, when the vehicle is in a starting state and the slope gradient is greater than the preset gradient and the vehicle gear is a driving gear, it is explained that the vehicle starts when advancing uphill, and at this time, the hydraulic braking force may be switched to the motor braking force.

For example, taking an example that the vehicle gear is reverse gear and the gradient of the ramp is greater than the preset gradient, when the vehicle is in a starting state and the gradient of the ramp is greater than the preset gradient and the vehicle gear of the vehicle is a driving gear, it is described that the vehicle starts when backing up to the reverse gear, that is, starts when the reverse gear is ascending, and at this time, the hydraulic braking force can be switched to the motor braking force.

Through the technical scheme, in the first aspect, under the condition that the vehicle gear is a driving gear, the accelerator opening is larger than the preset opening and the electronic parking brake is released, the user is determined to have a starting intention, and the hydraulic braking force is switched to the motor braking force before the vehicle really starts to run; the second aspect is that the hydraulic braking force is switched to the motor braking force only when the motor braking force is larger than the hydraulic braking force, so that the phenomenon of sliding vehicles when the motor braking force is adopted to brake the vehicles is avoided; in the third aspect, the hydraulic braking force is controlled to be switched to the motor braking force only when the vehicle starts on a hill, so that the situation that the vehicle starts on a flat ground and is switched to the motor braking force is avoided, and the waste of electric quantity resources is avoided.

An alternative embodiment of the present disclosure is described below, with reference to fig. 5, which is provided to illustrate how the motor braking force provided by the vehicle may be achieved.

(1) And obtaining the motor braking force according to the residual electric quantity of the vehicle and the environment temperature of the vehicle.

The remaining power of the vehicle may be the remaining power of a high-voltage battery of the vehicle, and the smaller the remaining power is, the smaller the motor braking force can be provided; the ambient temperature refers to the external ambient temperature of the vehicle, and the ambient temperature affects the braking force output by the target motor.

Therefore, the residual electric quantity and the ambient temperature of the vehicle can be used as input parameters of the first PID controller, and the vehicle is in a stationary state as a target, so that the motor braking force of the vehicle can be obtained. The stationary state of the vehicle is understood to be a state in which the vehicle speed is 0.

The first PID controller is a proportional-integral-derivative controller, and can continuously adjust the motor braking force according to the residual electric quantity and the ambient temperature, so that the output vehicle speed is continuously close to 0, and when the vehicle speed is close to 0, the motor braking force is the motor braking force output by the target motor.

(2) In the case where the motor braking force is greater than the hydraulic braking force, the motor braking force is applied to the wheels, and the vehicle is controlled to park.

Under the condition that the motor braking force output by the first PID controller is larger than the hydraulic braking force, the motor braking force is applied to wheels to realize parking; when the motor braking force output by the first PID controller is smaller than the hydraulic braking force, the motor braking force is not applied, and the original hydraulic braking force is maintained.

Of course, in the case where the accelerator opening is smaller than the preset opening or the vehicle gear is not the drive gear, the hydraulic braking force is not switched to the motor braking force.

Through the technical scheme, the motor braking force capable of enabling the vehicle to be in a static state can be obtained through the first PID controller according to the current residual electric quantity of the vehicle and the environment temperature of the vehicle.

Next, a specific embodiment relating to the above-described step S13 will be described, referring to fig. 5, for explaining how to gradually unload the motor braking force according to the gradually increasing driving force in the case where the driving force of the vehicle is greater than the running resistance of the vehicle.

And unloading the motor braking force applied to the wheels according to the driving force of the vehicle and the gradient of the slope on which the vehicle is positioned.

The driving force of the vehicle is inversely proportional to the motor braking force, and the greater the driving force of the vehicle, the smaller the target motor braking force applied to the wheels after the partial braking force is unloaded.

The gradient of the ramp determines the target gradient of the decrease of the motor braking force, please refer to the target gradient shown in fig. 4, the unloading of the motor braking force means that the motor braking force output by the target motor is controlled to decrease with the target gradient, the larger the gradient value is, the larger the running resistance of the vehicle is, the smaller the target gradient is, thereby ensuring that the motor braking force decreases at a slower speed, avoiding the vehicle from sliding down, and ensuring the safety of users in the vehicle.

Unloading the motor braking force applied to the wheels according to the driving force and the gradient of the hill includes: and taking the driving force and the slope gradient as input parameters of a second PID controller, and taking the vehicle as a stationary state as a target to obtain a target motor braking force after the motor braking force on the wheels is unloaded. The vehicle being stationary refers to a state in which the vehicle speed is 0.

The second PID controller is a proportional-integral-derivative controller, and can continuously unload the motor braking force according to the driving force and the gradient of the ramp, so that the output vehicle speed is continuously close to 0, and when the vehicle speed is close to 0, the motor braking force is the target motor braking force capable of enabling the vehicle to park on the ramp.

It will be appreciated that the above scheme refers to unloading the motor braking force, wherein the unloading gradually reduces the motor braking force until the motor braking force is 0, and the following scenario is that the target motor is directly controlled to not output the motor braking force.

And when the vehicle speed is greater than the preset vehicle speed, the motor braking force is smaller than the hydraulic braking force, the state of the electronic parking brake of the vehicle is unreleased, and any one of the target motor fault and the vehicle gear is the parking gear exists, the target motor is controlled not to output the motor braking force.

In the first case, when the vehicle speed is greater than the preset vehicle speed, the representative vehicle is in a running state, and the wheels can be parked without using the motor braking force, so that the motor braking force can be directly released.

In the second case, when the motor braking force is smaller than the hydraulic braking force, the target motor can be directly controlled not to output the motor braking force, and the target motor can cause the vehicle to roll even if the target motor outputs the motor braking force, so that the original logic is directly used for parking by adopting the hydraulic braking force.

In the third case, when the state of the electronic parking brake of the vehicle is unreleased, it is indicated that the user does not want to park, and at this time, the target motor can be controlled not to output the motor braking force, so that the user experience is prevented from being influenced.

In the fourth case, when the target motor fails, it is indicated that the target motor cannot output the motor braking force, so that the target motor can be controlled not to output the motor braking force,

In the fifth case, when the vehicle gear is the parking gear, it is indicated that the user does not have a start intention, and the vehicle needs to be parked at this time, so that the hydraulic braking force can be controlled to park without using the motor braking force.

It can be seen that in the case where any one of the above five conditions exists, it is explained that the hydraulic braking force cannot be switched to the motor braking force or the vehicle does not need to be braked. Referring to fig. 5, when the hydraulic braking force cannot be switched to the motor braking force, parking can be performed using the hydraulic braking force without parking using the motor braking force. After the hydraulic braking force is adopted for parking, when the accelerator opening of the vehicle is larger than the preset opening and the driving force of the vehicle is larger than the preset driving force, the hydraulic braking force is controlled to decline at a certain slope, and the hydraulic braking force gradually declines along with the increase of the driving force, so that the vehicle is in a parking state and cannot slip before actually starting.

According to the technical scheme, after the driving force of the vehicle overcomes the running resistance of the vehicle and has a forward trend, the motor braking force applied to the wheels is gradually unloaded through the second PID controller according to the driving force output by the motor of the front axle of the vehicle and the gradient of the ramp where the vehicle is located, so that the motor braking force of the rear axle is reasonably and smoothly released, the gradually reduced motor braking force can be matched with the gradually increased driving force, and the vehicle can be parked on the ramp in the process of unloading the motor braking force.

Of course, after the vehicle starts and resumes, the target motor is controlled to output motor driving force, so as to drive the rear wheels to rotate, so that the vehicle runs normally, at this time, the motor driving forces output by the front axle motor and the target motor of the rear axle are distributed in torque, and the motor driving forces are reasonably distributed to the left wheels and the right wheels of the vehicle, so that the driving smoothness of the vehicle is ensured.

An alternative embodiment of the disclosed embodiment is described below for explaining a starting system architecture for use in a hill start of a vehicle as referred to in the disclosed embodiment.

Referring to fig. 7, the starting system architecture includes an inertial measurement sensor (Inertial Measurement Unit, IMU), a vehicle harness, a pedal switch sensor (PAD), an electronic parking Brake (ELECTRICAL PARK Brake, EPB), an integrated Brake controller (INTEGRATE POWER BRAKE, IPB), a gear controller (Shift Control Uni, SCU), a motor controller (Motor Control Unit, MCU), a motor rotation speed sensor, a rotational sensor, a left domain controller, a right domain controller, a Brake, a Wheel Speed Sensor (WSS) of each wheel, wheels, and Brake pedals.

IPB controller: the controller is arranged in a braking system of the vehicle, and is used for controlling the braking pressure of each wheel by collecting information such as the depth of stepping on a brake pedal by a driver, the wheel speeds of four wheels, the current driving gear, the automatic parking requirement, the driving torque and the like and combining the current working condition and the driver requirement, so that the automatic parking and releasing functions are realized, and the automatic parking and releasing functions comprise the main functions of wheel anti-lock, traction control, vehicle body stability control and the like.

MCU controller and driving motor: the driving motor provides corresponding driving moment for the vehicle, the vehicle is ensured to run, and the driving motor comprises a front shaft motor and a rear shaft target motor.

IMU controller: the integrated VCU (vehicle control unit, vehicle controller) is internally and externally arranged outside the VCU controller, and mainly collects information such as vehicle transverse acceleration, longitudinal acceleration, yaw rate sensor and the like, and sends the information to a vehicle public CAN network for other modules to receive and use.

EPB controller: when a driver presses a button of an electronic parking brake or presses a brake pedal to send a PAD switch signal, the EPB controller applies corresponding current and direction to a motor of an actuating mechanism, torque output by the motor is increased through a speed reducing device, so that a brake piston is pushed to move, thrust is converted into pressure on a brake friction plate compressed brake disc, braking parking of the vehicle is achieved, and a parking system state signal is sent to an instrument to inform the driver.

PAD: the system is used for collecting signals which are collected and sent to the public CAN network of the whole vehicle according to requirements, and simultaneously displaying the schematic diagrams before and after the function execution to the driver through the PAD.

The SCU controller and motor rotation speed sensor of each wheel: the method is responsible for collecting the rotating speed of the corresponding motor of each wheel and is connected with the corresponding electric control, so that the electric control can obtain the actual rotating speed of the current motor and send a rotating speed signal to the VCU controller. And acquiring the current gear of the vehicle and sending the current gear to the CAN bus of the whole vehicle.

Left and right domain controllers: and the system is responsible for collecting actual information of the main driving door and the main driving seat safety belt of the vehicle and sending the information to the CAN bus.

Wheel speed sensor of each wheel: the system is responsible for collecting the rotating speed of each wheel and is connected with the vehicle stability controller, so that the vehicle stability controller can obtain the actual rotating speed of the current wheel and send a rotating speed signal to the VCU controller.

Spin-change sensors for each motor: the micro rotation direction and rotation amount of each driving motor are measured through the sensor body, the head and the measuring device, and the information is fed back to the control system.

Each wheel: is the final application end of the driving moment, feedback moment and braking moment of the vehicle to the road surface.

A brake: the braking torque of the vehicle is applied to the friction plate through hydraulic pressure, and the friction plate is applied to the brake disc, so that braking and parking functions are realized.

A brake pedal: the brake input source of the driver realizes the brake pressure through the depth of the driver stepping on the brake pedal.

Having described the function of the various components in the launch system architecture described above, the following describes how the various components in the launch system interact to achieve a reduction in braking noise at launch.

Fig. 8 is a schematic diagram of a framework of functional signal interaction shown in an embodiment of the disclosure.

Referring to fig. 8, after collecting signals such as a brake depth signal, a brake fluid pressure signal, a vehicle body inertia signal, a wheel speed signal, a longitudinal acceleration signal, an automatic parking state and fault signal, a motor parking request signal, etc., the IPB controller sends the signals to corresponding controllers including but not limited to an MCU controller, a PAD, an EPB controller and a VCU controller, and simultaneously controls the hydraulic caliper to establish and release hydraulic braking as required.

It is to be understood that the IPB controller controls hydraulic braking, and the IPB controller controls only motor braking at the time of hill start, but does not control motor braking at the time of traveling on a flat road surface, and the VCU control target motor output driving force at the time of traveling on a flat road surface.

The VCU controller can collect accelerator depth signals, motor parking state signals and required torque signals and send the signals to the IPB controller, and meanwhile, driving torque output by target motors of each front shaft motor and each rear shaft motor is controlled according to driver requirements.

The MCU controller can collect motor rotation speed signals, motor fault position signals and motor rotation change signals and send the motor rotation change signals to the IPB controller and the VCU controller, and meanwhile, driving torque of each motor is controlled according to VCU requirements.

In the disclosed embodiment, the IPB controller transmits the collected signals such as a braking depth signal, a brake fluid pressure signal, a vehicle body inertia signal, a wheel speed signal, a longitudinal acceleration signal, an automatic parking state and fault signal, a motor parking request signal and the like to the VCU controller, and the VCU controller judges the time for switching the hydraulic brake to the motor brake, the switching time and whether the hydraulic brake can be switched to the motor brake according to the signals; when the VCU controller judges that the hydraulic braking can be switched to motor braking, a switching signal is sent to the MCU controller; the MCU controller sends control signals to each device such as a target motor and hydraulic braking devices to execute, so that switching from hydraulic braking to motor braking is completed.

Fig. 9 is a vehicle control apparatus according to an exemplary embodiment, the vehicle control apparatus 900 including: an identification module 910, a switching module 920, and an offloading module 930.

An identification module 910 configured to identify a driving state of the vehicle in a case where it is determined that the vehicle is in a stationary state, a hydraulic braking force is applied to wheels, and a target motor is operating normally; the hydraulic braking force is a braking force provided by brake fluid;

A switching module 920 configured to switch the hydraulic braking force applied to the wheels to the motor braking force in the case where the driving state is a start state; the motor braking force is a braking force provided by the target motor;

An unloading module 930 configured to unload a motor braking force applied to the wheels in a case where a driving force of the vehicle is greater than a running resistance of the vehicle.

Optionally, the wheel is a rear wheel of the vehicle; the switching module 920 includes:

A first switching sub-module configured to switch a hydraulic braking force applied to the rear wheels to a motor braking force in a case where the driving state is a starting state.

Optionally, the driving state of the vehicle includes a vehicle gear, an accelerator opening and a state of an electronic parking brake; the identification module 910 includes:

the first identification submodule is configured to identify the gear of the vehicle, the opening degree of the accelerator and the state of the electronic parking brake under the condition that the vehicle is in a static state, hydraulic braking force is applied to wheels and a target motor normally runs;

and the second identification sub-module is configured to determine that the driving state is a starting state when the vehicle gear is a driving gear, the accelerator opening is larger than a preset opening and the state of the electronic parking brake is released.

Optionally, the switching module 920 includes:

A second switching sub-module configured to switch the hydraulic braking force applied to the wheels to a motor braking force in a case where the driving state is a start state and the motor braking force is greater than the hydraulic braking force.

Optionally, the switching module 920 includes:

And the third switching sub-module is configured to switch the hydraulic braking force applied to the wheels to the motor braking force under the condition that the driving state is a starting state and the gradient of the slope on which the vehicle is positioned is larger than the preset gradient.

Optionally, the vehicle control device 900 includes:

The calculation module is configured to obtain the motor braking force according to the residual electric quantity of the vehicle and the environment temperature of the vehicle;

an application module configured to apply the motor braking force to the wheels and control the vehicle to park.

Optionally, the computing module includes:

And the first calculation sub-module is configured to take the residual electric quantity and the ambient temperature as input parameters of a first PID controller, and target that the vehicle is in a stationary state to obtain the motor braking force.

Optionally, the unloading module 930 includes:

An unloading submodule configured to unload a motor braking force applied to the wheels according to a driving force of the vehicle and a slope gradient on which the vehicle is located; the driving force of the vehicle is inversely proportional to the motor braking force.

Optionally, the unloading submodule includes:

And the second calculation sub-module is configured to take the driving force and the gradient of the ramp as input parameters of a second PID controller, and target the stationary state of the vehicle to obtain target motor braking force after the motor braking force on the wheels is unloaded.

Optionally, the vehicle control device 900 includes:

a control module configured to control the target motor not to output a motor braking force in the presence of at least one of the following conditions: the speed of the vehicle is larger than the preset speed, the motor braking force is smaller than the hydraulic braking force, the state of the electronic parking brake of the vehicle is unreleased, and the target motor fault and the vehicle gear are parking gears.

Based on the same inventive concept, the disclosed embodiments propose a controller for performing the vehicle control method proposed by the disclosed embodiments, which may be a VCU controller.

Based on the same inventive concept, embodiments of the present disclosure provide a vehicle on which an IPB controller, a VCU controller, and an MCU controller are configured. The IPB controller sends the collected signals such as the braking depth signal, the brake fluid pressure signal, the vehicle body inertia signal, the wheel speed signal, the longitudinal acceleration signal, the automatic parking state and fault signal, the motor parking request signal and the like to the VCU controller, and the VCU controller judges the time for switching the hydraulic brake into the motor brake, the switching time and whether the hydraulic brake can be switched into the motor brake or not according to the signals; when the VCU controller judges that the hydraulic braking can be switched to motor braking, a switching signal is sent to the MCU controller; the MCU controller sends control signals to each device such as a target motor and hydraulic braking devices to execute, so that switching from hydraulic braking to motor braking is completed.

The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, but the present disclosure is not limited to the specific details of the embodiments described above, and various simple modifications may be made to the technical solutions of the present disclosure within the scope of the technical concept of the present disclosure, and all the simple modifications belong to the protection scope of the present disclosure.

In addition, the specific features described in the foregoing embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, the present disclosure does not further describe various possible combinations.

Moreover, any combination between the various embodiments of the present disclosure is possible as long as it does not depart from the spirit of the present disclosure, which should also be construed as the disclosure of the present disclosure.

Claims

1. A vehicle control method characterized by comprising:

2. The method of claim 1, wherein the wheel is a rear wheel of the vehicle; the switching of the hydraulic braking force applied to the wheels to the motor braking force when the driving state is a start state includes:

3. The method of claim 1, wherein the driving state of the vehicle includes a vehicle gear, an accelerator opening, and a state of an electronic parking brake; the identifying a driving state of the vehicle in a case where it is determined that the vehicle is in a stationary state, hydraulic braking force is applied to wheels, and a target motor is operating normally includes:

4. The method according to claim 1, wherein, in the case where the driving state is a starting state, switching the hydraulic braking force applied to the wheels to the motor braking force includes:

5. The method according to claim 1, wherein, in the case where the driving state is a starting state, switching the hydraulic braking force applied to the wheels to the motor braking force includes:

6. The method according to claim 1, wherein the method further comprises:

7. The method according to claim 6, wherein the obtaining the motor braking force based on the remaining amount of electricity of the vehicle and the ambient temperature in which the vehicle is located includes:

8. The method according to claim 1, wherein the unloading the motor braking force applied to the wheels in the case where the driving force of the vehicle is greater than the running resistance of the vehicle, includes:

9. The method according to claim 8, wherein unloading the motor braking force applied to the wheels according to the driving force of the vehicle and the slope gradient of the slope on which the vehicle is located, comprises:

10. The method according to claim 1, wherein the method further comprises:

11. A controller, characterized in that the method according to any one of claims 1-10 is performed.

12. A vehicle having the controller according to claim 11 disposed thereon.