CN118790207A - Vehicle control method, device and vehicle - Google Patents

Abstract

The present application relates to a vehicle control method, device and vehicle. The method comprises: obtaining the current wheel speed of the wheels in the target vehicle under the current braking behavior, the current piston pressure of the brake piston and the current pedal stroke of the brake pedal; determining the current friction coefficient of the friction brake member in the target vehicle according to the current wheel speed and the current piston pressure; determining the target braking strength of the brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke when the current friction coefficient meets the braking force attenuation condition; and performing braking control on the target vehicle according to the target braking strength. The method can improve the accuracy of braking control on the target vehicle.

Description

Vehicle control method, device and vehicle

Technical Field

The present application relates to the field of vehicle control technology, and in particular to a vehicle control method, device and vehicle.

Background Art

As vehicles move toward electrification and intelligence, the brake pedal of vehicles has promoted the transformation and upgrading of vehicles with its universalization, integration and wire control level. In the implementation of the current dry braking solution of the wire control brake system, in order to give the driver the same braking feeling as the traditional brake system, a brake pedal simulator is usually set in the wire control brake system to ensure that the driver can accurately grasp the braking intensity applied to the pedal to achieve control of the vehicle.

However, the pedal simulator design only relies on pedal travel to identify braking intentions, and does not have a master cylinder pressure feedback mechanism, such as a traditional wet hydraulic brake system, to transmit braking reaction force to the driver. In addition, the current fully decoupled hydraulic control system is centered on minimizing the user's perception of hydraulic pressure feedback to ensure consistent foot feel under braking force control. However, when the braking system decays in this design, the driver cannot perceive it in time and continues to drive aggressively until the system fails, causing safety hazards.

Summary of the invention

Based on this, it is necessary to provide a vehicle control method, device and vehicle that can accurately control the braking process of the vehicle in response to the above technical problems.

In a first aspect, the present application provides a vehicle control method, comprising:

Obtaining the current wheel speed of the wheels of the target vehicle under the current braking behavior, the current piston pressure of the brake piston, and the current pedal travel of the brake pedal;

determining a current friction coefficient of a friction brake member in the target vehicle according to the current wheel speed and the current piston pressure;

In the case where the current friction coefficient satisfies the braking force attenuation condition, determining a target braking intensity of the brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke;

The target vehicle is braked according to the target braking intensity.

In one of the embodiments, determining the target braking intensity of the brake pedal in the target vehicle based on the current friction coefficient and the current pedal stroke includes: determining a reference braking intensity of the brake pedal under the current pedal stroke; determining a current fade compensation coefficient of the brake pedal based on the current friction coefficient and the current pedal stroke; determining the target braking intensity of the brake pedal based on the product of the current fade compensation coefficient and the reference braking intensity.

In one embodiment, determining the current fade compensation coefficient of the brake pedal based on the current friction coefficient and the current pedal stroke includes: determining the current degree of brake weakening of the brake pedal under the current friction coefficient; based on a preset exponential function, exponentially decaying the difference between the current pedal stroke and the current degree of brake weakening according to a first preset smoothing coefficient to determine the current fade compensation coefficient.

In one of the embodiments, braking control is performed on the target vehicle according to the target braking strength, including: determining a first offset compensation strength of the brake pedal according to the current degree of brake weakening, the current pedal stroke and the maximum pedal stroke of the brake pedal; accumulating the first offset compensation strength on the target braking strength to update the target braking strength; and braking control is performed on the target vehicle according to the updated target braking strength.

In one embodiment, the first offset compensation strength of the brake pedal is determined according to the current degree of brake weakening, the current pedal stroke and the maximum pedal stroke of the brake pedal, including: based on the preset exponential function, according to a second preset smoothing coefficient, exponentially decaying the difference between the current pedal stroke and the maximum pedal stroke to determine a first basic compensation strength; wherein the second preset smoothing coefficient is 1; based on the preset exponential function, according to the first preset smoothing coefficient, exponentially decaying the difference between the maximum pedal stroke and the current degree of brake weakening to obtain an offset compensation coefficient; determining the first offset compensation strength of the brake pedal according to the product of the offset compensation coefficient and the first basic compensation strength.

In one of the embodiments, braking control is performed on the target vehicle according to the target braking intensity, including: determining a second offset compensation intensity of the brake pedal according to the maximum pedal stroke, the current degree of brake weakening and the minimum pedal stroke of the brake pedal; reducing the second offset compensation intensity on the target braking intensity to update the target braking intensity; and braking control is performed on the target vehicle according to the updated target braking intensity.

In one embodiment, the second offset compensation strength of the brake pedal is determined based on the maximum pedal stroke, the current degree of brake weakening and the minimum pedal stroke of the brake pedal, including: based on the preset exponential function, according to the second preset smoothing coefficient, exponentially decaying the difference between the minimum pedal stroke and the maximum pedal stroke to determine the second basic compensation strength; based on the preset exponential function, according to the first preset smoothing coefficient, exponentially decaying the difference between the maximum pedal stroke and the current degree of brake weakening to obtain the offset compensation coefficient; determining the second offset compensation strength of the brake pedal based on the product of the offset compensation coefficient and the second basic compensation strength.

In one embodiment, determining the current braking weakening degree of the brake pedal under the current friction coefficient includes: determining a first braking weakening degree of the brake pedal under the current friction coefficient; if the current braking behavior is the first braking behavior, selecting the smaller value between the first braking weakening degree and the default instantaneous braking weakening degree as the current braking weakening degree of the brake pedal; if the current braking behavior is not the first braking behavior, determining the instantaneous braking weakening degree of the current braking behavior based on the instantaneous braking weakening degree corresponding to the previous braking behavior of the current braking behavior, the historical pedal travel of the previous braking behavior, and the braking interval between the current braking behavior and the previous braking behavior, and selecting the smaller value between the first braking weakening degree and the instantaneous braking weakening degree of the current braking behavior as the current braking weakening degree of the brake pedal.

In one embodiment, the instantaneous braking weakening degree of the current braking behavior is determined based on the instantaneous braking weakening degree corresponding to the previous braking behavior of the current braking behavior, the historical pedal stroke of the previous braking behavior, and the braking interval between the current braking behavior and the previous braking behavior, including: determining the instantaneous braking weakening amplitude based on the product of the historical pedal stroke of the previous braking behavior and a preset pedaling amplitude; and determining the instantaneous braking compensation amplitude based on the product of the braking interval and a preset compensation amplitude; determining the instantaneous braking weakening degree of the current braking behavior based on the instantaneous braking weakening degree corresponding to the previous braking behavior, the instantaneous braking weakening amplitude and the instantaneous braking compensation amplitude.

In one embodiment, the instantaneous braking weakening degree of the current braking behavior is determined based on the instantaneous braking weakening degree corresponding to the previous braking behavior, the instantaneous braking weakening amplitude and the instantaneous braking compensation amplitude, including: selecting the larger value between the target difference and the default braking weakening degree as the second braking weakening degree; the target difference is the difference between the instantaneous braking weakening degree corresponding to the previous braking behavior and the instantaneous braking weakening amplitude; and taking the sum of the second braking weakening degree and the instantaneous braking compensation amplitude as the instantaneous braking weakening degree of the current braking behavior.

In a second aspect, the present application also provides a vehicle control device, comprising:

An information acquisition module, used to acquire the current wheel speed of the wheels of the target vehicle under the current braking behavior, the current piston pressure of the brake piston and the current pedal travel of the brake pedal;

a coefficient determination module, configured to determine a current friction coefficient of a friction brake member in the target vehicle according to the current wheel speed and the current piston pressure;

a strength determination module, configured to determine a target braking strength of a brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke when the current friction coefficient satisfies a braking force attenuation condition;

A braking control module is used to perform braking control on the target vehicle according to the target braking intensity.

In a third aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

Obtaining the current wheel speed of the wheels of the target vehicle under the current braking behavior, the current piston pressure of the brake piston, and the current pedal travel of the brake pedal;

determining a current friction coefficient of a friction brake member in the target vehicle according to the current wheel speed and the current piston pressure;

In the case where the current friction coefficient satisfies the braking force attenuation condition, determining a target braking intensity of the brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke;

The target vehicle is braked according to the target braking intensity.

In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the following steps are implemented:

Obtaining the current wheel speed of the wheels of the target vehicle under the current braking behavior, the current piston pressure of the brake piston, and the current pedal travel of the brake pedal;

determining a current friction coefficient of a friction brake member in the target vehicle according to the current wheel speed and the current piston pressure;

In the case where the current friction coefficient satisfies the braking force attenuation condition, determining a target braking intensity of the brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke;

The target vehicle is braked according to the target braking intensity.

In a fifth aspect, the present application further provides a computer program product, including a computer program, which implements the following steps when executed by a processor:

Obtaining the current wheel speed of the wheels of the target vehicle under the current braking behavior, the current piston pressure of the brake piston, and the current pedal travel of the brake pedal;

determining a current friction coefficient of a friction brake member in the target vehicle according to the current wheel speed and the current piston pressure;

In the case where the current friction coefficient satisfies the braking force attenuation condition, determining a target braking intensity of the brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke;

The target vehicle is braked according to the target braking intensity.

In a sixth aspect, the present application further provides a vehicle, wherein the vehicle is provided with a device for implementing the following method steps:

Obtaining the current wheel speed of the wheels of the target vehicle under the current braking behavior, the current piston pressure of the brake piston, and the current pedal travel of the brake pedal;

determining a current friction coefficient of a friction brake member in the target vehicle according to the current wheel speed and the current piston pressure;

In the case where the current friction coefficient satisfies the braking force attenuation condition, determining a target braking intensity of the brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke;

The target vehicle is braked according to the target braking intensity.

The above vehicle control method, device and vehicle, after obtaining the current wheel speed of the wheel in the target vehicle under the current braking behavior, the current piston pressure of the brake piston and the current pedal stroke of the brake pedal, determine the current friction coefficient of the friction brake in the target vehicle according to the current wheel speed and the current piston pressure; further, when the current friction coefficient meets the braking force attenuation condition, determine the target braking strength of the brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke, and perform braking control on the target vehicle according to the target braking strength. The above scheme introduces the current friction coefficient and accurately detects whether the target vehicle enters the braking force attenuation state according to the friction coefficient; when it is determined that the target vehicle enters the braking force attenuation state, the perception of the weakened braking performance is realized according to the current friction coefficient and the current pedal stroke, and the braking strength of the target vehicle in the braking force attenuation state is accurately simulated; in addition, since the current wheel speed, the current piston pressure and the current pedal stroke are real-time acquired data, the timeliness and accuracy of the determined target braking strength are guaranteed, thereby realizing effective and precise control of the braking process of the target vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

FIG1 is an application environment diagram of a vehicle control method according to an embodiment;

FIG2 is a schematic flow chart of a vehicle control method in one embodiment;

FIG3 is a curve showing the variation of the friction coefficient of the friction brake member with the temperature of the brake material in one embodiment;

FIG4 is a curve showing the change of braking strength with braking stroke at different degrees of brake weakening in one embodiment;

FIG5 is a comparison diagram of the curves of the braking intensity versus the pedal stroke of the present application and the prior art in one embodiment;

FIG6 is a schematic flow chart of a vehicle control method in another embodiment;

FIG7 is a block diagram of a vehicle control device according to an embodiment;

FIG. 8 is a diagram showing the internal structure of a computer device in one embodiment.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

The vehicle control method provided in the embodiment of the present application can be applied in the application environment as shown in FIG1 . Among them, the braking system 110 is a system for controlling the vehicle speed in the target vehicle, and the wire-controlled chassis angle controller 120 is a device in the target vehicle that monitors and controls the operating state of the target vehicle through electrical signals. Optionally, the braking system 110 obtains the current wheel speed of the wheel in the target vehicle under the current braking behavior monitored by the wire-controlled chassis angle controller 120, the current piston pressure of the brake piston, and the current pedal stroke of the brake pedal; and determines the current friction coefficient of the friction brake part in the target vehicle based on the current wheel speed and the current piston pressure; further, when the current friction coefficient meets the braking force attenuation condition, the target braking strength of the brake pedal in the target vehicle is determined based on the current friction coefficient and the current pedal stroke; and the target vehicle is braked and controlled based on the target braking strength.

In one embodiment, as shown in FIG. 2 , a vehicle control method is provided, which is described by taking the method applied to the braking system 110 in FIG. 1 as an example, and specifically includes the following steps:

S210, obtaining the current wheel speed of the wheels of the target vehicle under the current braking behavior, the current piston pressure of the brake piston, and the current pedal travel of the brake pedal.

Among them, braking behavior is an act of controlling the speed of the vehicle by stepping on the brake pedal; current braking behavior refers to the braking behavior generated by the driver of the target vehicle at the current stepping moment. The current wheel speed is the rotation speed of the wheels of the target vehicle at the current stepping moment; the brake piston is a device in the target vehicle used to increase the braking force, improve the stability and smoothness of the brake; the current piston pressure is the pressure that the brake piston bears at the current stepping moment; the brake pedal is a pedal used to limit the speed of the target vehicle, that is, the brake pedal; the current pedal stroke is the stroke of the brake pedal at the current stepping moment.

Optionally, when the driver of the target vehicle needs to control the deceleration of the target vehicle, the driver will control the deceleration of the target vehicle by stepping on the brake pedal in the target vehicle; at this time, the target vehicle will recognize the current braking behavior of the driver. Further, under the current braking behavior, the vehicle status data such as the current wheel speed of the wheel in the target vehicle, the current piston pressure of the brake piston, and the current pedal travel of the brake pedal monitored in real time by the wire-controlled chassis angle controller are obtained.

It should be noted that, in the embodiment of the present application, the pedal stroke may range from 0% to 100%, or may be a numerical range corresponding to 0% to 100% and scaled in equal proportion, such as 0 to 10. That is, the pedal stroke may be presented in the form of a percentage or a number.

S220: Determine a current friction coefficient of a friction brake component in the target vehicle according to the current wheel speed and the current piston pressure.

The friction brake is a component used to decelerate the target vehicle, and may include at least one of a brake disc and a brake drum, etc., and the present application does not impose any limitation on this. The current friction coefficient is the friction coefficient of the friction brake in the target vehicle at the current stepping moment.

Optionally, considering that there are many factors involved in the actual calculation of the friction coefficient, in the embodiment of the present application, the friction coefficient can be directly estimated based on the wheel speed and the piston pressure. In other words, the current friction coefficient of the friction brake in the target vehicle can be calculated based on the current wheel speed and the current piston pressure. Specifically, the current friction coefficient can be expressed by the following formula (1):

(1)

in, is the current friction coefficient; The simplified preset fixed coefficient can be determined by experiment; is the current piston pressure; is the current wheel speed.

For example, the current friction coefficient of each wheel of the target vehicle can be determined according to formula (1), and the current friction coefficient of the target vehicle can be determined based on the statistical results of the current friction coefficients of each wheel. The statistical results can be average values, second largest values, or preset quantiles, etc., and this application does not impose any limitation on this.

S230: When the current friction coefficient satisfies the braking force attenuation condition, a target braking intensity of the brake pedal in the target vehicle is determined according to the current friction coefficient and the current pedal travel.

The braking force attenuation condition is a condition that needs to be met for the braking performance to weaken. The target braking intensity represents the braking capacity of the brake pedal.

It is understandable that the brake material in the target vehicle can maintain a relatively ideal performance within the set temperature. However, if the temperature of the brake material is not within the set temperature range, the performance of the brake material will be reduced and unstable. In this case, the friction coefficient of the friction brake component decreases, resulting in a weakened braking performance. The curve of the friction coefficient of the friction brake component in the target vehicle changing with the temperature of the brake material as shown in Figure 3. When the temperature of the brake material is too low or too high (that is, not within the set temperature range), the friction coefficient is lower than a preset threshold. Therefore, it is possible to determine whether the target vehicle needs to enter a state of braking force attenuation based on the relationship between the friction coefficient and the preset threshold.

Optionally, if the current friction coefficient is lower than the preset friction coefficient threshold, it means that the current friction coefficient meets the braking force attenuation condition. At this time, it is necessary to combine the actual operating law of the target vehicle under the braking force attenuation state, and simulate the braking strength of the brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke to obtain the target braking strength of the brake pedal in the target vehicle. If the current friction coefficient is not lower than the preset friction coefficient threshold, the traditional method can be used to directly determine the target braking strength of the brake pedal in the target vehicle based on the product of the current pedal stroke and the preset coefficient.

It is worth noting that, referring to Figure 3, when the friction coefficient of the friction brake of the target vehicle exceeds a certain threshold, the braking system of the target vehicle can no longer provide sufficient braking force for safe driving of the vehicle. In this case, an early warning is sent to the driver to remind the driver that the target vehicle needs to enter a degraded operation mechanism, thereby guiding the driver to take necessary intervention measures in a timely manner, such as reducing the speed or pulling over.

S240, performing braking control on the target vehicle according to the target braking intensity.

After obtaining the current wheel speed of the wheel in the target vehicle under the current braking behavior, the current piston pressure of the brake piston and the current pedal stroke of the brake pedal, the embodiment of the present application determines the current friction coefficient of the friction brake in the target vehicle according to the current wheel speed and the current piston pressure; further, when the current friction coefficient meets the braking force attenuation condition, the target braking strength of the brake pedal in the target vehicle is determined according to the current friction coefficient and the current pedal stroke, and the target vehicle is braked according to the target braking strength. The above scheme introduces the current friction coefficient and accurately detects whether the target vehicle enters the braking force attenuation state according to the friction coefficient; when it is determined that the target vehicle enters the braking force attenuation state, the perception of the weakened braking performance is realized according to the current friction coefficient and the current pedal stroke, and the braking strength of the target vehicle in the braking force attenuation state is accurately simulated; in addition, since the current wheel speed, the current piston pressure and the current pedal stroke are real-time acquired data, the timeliness and accuracy of the determined target braking strength are guaranteed, thereby realizing effective and precise control of the braking process of the target vehicle.

On the basis of the technical solutions of the above embodiments, in order to ensure the accuracy of the determined target braking intensity, the present application further provides an optional embodiment, in which the step of determining the target braking intensity of S230 is refined, and the step includes:

S410, determining a reference braking strength of the brake pedal under the current pedal stroke.

The reference braking intensity is used to characterize the pedal intensity corresponding to the brake pedal in the target vehicle determined by traditional methods, and at this time the driver cannot perceive any foot feedback of the piston force.

Exemplarily, the reference braking intensity of the brake pedal under the current pedal stroke may be determined according to the product of the current pedal stroke and the first preset coefficient.

The first preset coefficient can be understood as a mapping coefficient between the current pedal stroke and the reference braking strength, through which the current pedal stroke can be converted into the braking strength of the brake pedal. It is worth noting that the first preset coefficients corresponding to different current pedal strokes can be the same or different, and can be determined through a large number of experiments, and this application does not impose any limitation on this.

Specifically, the reference braking intensity can be expressed by the following formula (2):

(2)

in, is the reference braking intensity; is the first preset coefficient; is the current pedal travel.

S420: Determine a current fade compensation coefficient of the brake pedal according to the current friction coefficient and the current pedal travel.

The current decay compensation coefficient is a coefficient that needs to be used to perform decay compensation on the reference braking intensity.

Optionally, in order to enable the driving user to clearly perceive the weak front-end travel control of the braking strength of the target vehicle braking system and the increase in the required braking force, in the embodiment of the present application, an exponential function is used to simulate the braking force decay process of the brake pedal. Specifically, the current decay compensation coefficient constructed by the exponential function model can be expressed by the following formula (3):

(3)

in, is the current recession compensation coefficient; is the current friction coefficient; Represents a function related to the current pedal travel and the current friction coefficient.

Furthermore, in order to ensure the accuracy and rationality of the determined current fading compensation coefficient, a parameter of brake weakening degree may be introduced to numerically quantify the degree to which the brake pedal feel needs to be weakened.

Optionally, considering that the degree of brake weakening is proportional to the friction coefficient, the current degree of brake weakening of the brake pedal under the current friction coefficient can be determined; based on a preset exponential function, according to a first preset smoothing coefficient, the difference between the current pedal stroke and the current degree of brake weakening is exponentially decayed to determine the current decay compensation coefficient. The preset exponential function is a pre-set exponential function used to simulate the braking force decay process of the brake pedal.

Exemplarily, the current brake weakening degree of the brake pedal under the current friction coefficient may be determined based on the product of the current friction coefficient and the second preset coefficient.

Among them, the current brake weakening degree is used to characterize the quantitative degree value when the reference brake strength is weakened in order to allow the driving user to perceive the foot feel feedback of the piston force. Among them, the second preset coefficient can be understood as a mapping coefficient between the current friction coefficient and the current brake weakening degree, through which the current friction coefficient can be converted into the current brake weakening degree when the braking strength of the brake pedal is weakened. It is worth noting that the second preset coefficients corresponding to different current friction coefficients can be the same or different, and can be determined through a large number of experiments, and this application does not impose any restrictions on this. It should be noted that the second preset coefficient is independent of the aforementioned first preset coefficient.

Therefore, the current brake weakening degree can be expressed by the following formula (4):

(4)

in, is the current brake weakening degree; is the second preset coefficient.

Furthermore, in the above formula (3) , can be expressed by the following formula (5):

(5)

in, is the first preset smoothing coefficient, which is a positive number not greater than 1 and is used to characterize the attenuation degree corresponding to the exponential decay process. Its specific value can be set based on experience or determined through a large number of experiments, and this application does not impose any limitation on this. In a specific implementation, the first preset smoothing coefficient can be 0.5.

Finally, combining the above formula (3) and formula (5), the current decay compensation coefficient can be expressed by the following formula (6):

(6)

S430: Determine a target braking intensity of the brake pedal according to the product of the current fade compensation coefficient and the reference braking intensity.

The target braking intensity is the result of reducing the braking force of the reference braking intensity of the brake pedal, so as to achieve the purpose of enabling the driving user to feel the foot feel feedback of the piston force.

Optionally, the product of the current decay compensation coefficient and the reference braking strength can be directly used as the target braking strength of the brake pedal. Specifically, the target braking strength of the brake pedal can be expressed by the following formula (7):

(7)

in, Indicates the target braking strength of the brake pedal.

The embodiment of the present application introduces the current fade compensation coefficient of the brake pedal according to the current friction coefficient and the current pedal travel, and performs fade compensation on the reference braking intensity based on the current fade compensation coefficient on the existing reference braking intensity, thereby accurately simulating the target braking intensity of the target vehicle under the braking force attenuation state.

On the basis of the technical solutions of the above embodiments, in order to achieve precise braking control of the target vehicle, the present application also provides an optional embodiment. In this optional embodiment, the braking control step in S240 is refined, and the step includes:

S510: Determine a first offset compensation strength of the brake pedal according to a current brake weakening degree, a current pedal stroke, and a maximum pedal stroke of the brake pedal.

The first offset compensation strength is used to compensate for the braking strength value when the brake pedal reaches 100% travel.

Optionally, in the embodiment of the present application, an exponential function model is introduced to simulate the braking force decay process of the brake pedal, but since the exponential function cannot reach infinity, the original braking intensity value (i.e., the reference braking intensity) cannot be fully reached when the brake pedal reaches 100% travel. Therefore, it is necessary to introduce the first offset compensation intensity of the brake pedal to compensate the brake pedal.

Optionally, the actual braking strength of the brake pedal when it reaches 100% of the stroke can be comprehensively considered and combined with the characteristics of the exponential function model to derive a calculation method for the first offset compensation strength. Furthermore, based on the calculation method of the first offset compensation strength, the first offset compensation strength of the brake pedal can be determined according to the current degree of brake weakening, the current pedal stroke and the maximum pedal stroke of the brake pedal.

S520: Accumulate the first offset compensation intensity on the target braking intensity to update the target braking intensity.

Optionally, in order to compensate for the target braking strength, the first offset compensation strength is accumulated on the basis of the target braking strength, and the target braking strength is updated to obtain an updated target braking strength. Specifically, based on the above formula (7), the first offset compensation strength is accumulated to obtain an updated target braking strength, which can be specifically shown by the following formula (8):

(8)

in, is the updated target braking intensity; is the first offset compensation strength.

S530: Perform braking control on the target vehicle according to the updated target braking intensity.

Optionally, braking control is performed on the target vehicle based on the updated target braking intensity, replacing the target braking intensity before the update.

The embodiment of the present application introduces a first offset compensation strength of the brake pedal according to the current degree of brake weakening, the current pedal stroke and the maximum pedal stroke of the brake pedal, and compensates the target braking strength according to the first offset compensation strength, thereby ensuring that when the brake pedal reaches 100% of the stroke, the braking strength of the target vehicle can be accurately simulated, thereby further realizing precise braking control of the target vehicle.

On the basis of the technical solutions of the above embodiments, in order to ensure the accuracy of the determined first offset compensation, the present application further provides an optional embodiment. In this optional embodiment, the step of determining the first offset compensation strength in S510 is refined, and the step includes:

S610 , based on a preset exponential function and according to a second preset smoothing coefficient, exponentially decay the difference between the current pedal stroke and the maximum pedal stroke to determine a first basic compensation intensity.

The second preset smoothing coefficient is used to characterize the attenuation degree corresponding to the maximum attenuation in the exponential attenuation process; the second preset smoothing coefficient can be 1, or any value fluctuating around 1, and the specific fluctuation range can be determined based on experience or through a large number of experiments. It can be understood that by performing the maximum exponential attenuation on the difference between the current pedal stroke and the maximum pedal stroke, a relatively fixed first basic compensation strength can be obtained.

Optionally, based on a preset exponential function and according to a second preset smoothing coefficient, the difference between the current pedal stroke and the maximum pedal stroke is exponentially decayed to determine the first basic compensation strength, which can be expressed by the following formula (9):

(9)

in, is the first basic compensation intensity; is a second preset smoothing coefficient; is the current pedal travel; is the maximum pedal stroke. It should be noted that when When , the above formula (9) Does not need to participate in the calculation process.

S620: Based on a preset exponential function and according to a first preset smoothing coefficient, exponentially decay the difference between the maximum pedal travel and the current brake weakening degree to obtain an offset compensation coefficient.

The offset compensation coefficient is used to characterize the degree of compensation when offset compensation is performed on the target braking intensity at 100% stroke on the basis of the first basic compensation intensity.

Optionally, based on a preset exponential function, according to a first preset smoothing coefficient, the difference between the maximum pedal stroke and the current brake weakening degree is exponentially decayed to obtain the offset compensation coefficient, which can be expressed by the following formula (10):

(10)

in, is the offset compensation coefficient; is a first preset smoothing coefficient; is the maximum pedal travel; Indicates the current degree of brake weakening.

S630: Determine a first offset compensation strength of the brake pedal according to the product of the offset compensation coefficient and the first basic compensation strength.

Optionally, in order to ensure the accuracy of the first offset compensation strength, a first preset coefficient is introduced for optimization based on the offset compensation coefficient. Further, according to the product of the offset compensation coefficient and the first basic compensation strength, the first offset compensation strength of the brake pedal can be expressed by the following formula (11):

(11)

in, Indicates the first preset coefficient.

The embodiment of the present application fully considers the actual state of the target vehicle by introducing the offset compensation coefficient and the first basic compensation strength, thereby ensuring the accuracy of the first offset compensation strength of the brake pedal determined according to the product of the offset compensation coefficient and the first basic compensation strength.

On the basis of the technical solutions of the above embodiments, in order to further improve the accuracy of the braking process, the present application also provides an optional embodiment. In this optional embodiment, the braking control step in S240 is refined, and the step includes:

S710: Determine a second offset compensation strength of the brake pedal according to the maximum pedal travel, the current brake weakening degree, and the minimum pedal travel of the brake pedal.

The second offset compensation strength is used to compensate for the braking strength value when the brake pedal is at 0% travel.

Optionally, for the same consideration, the introduced exponential function cannot reach infinity. At the starting position (i.e., when the brake pedal is at 0% travel), to ensure that when the braking force demand is 0%, the actual output braking intensity should also be 0, it is necessary to introduce a second offset compensation intensity for compensation. Further, based on the preset exponential function, according to the second preset smoothing coefficient, the difference between the minimum pedal travel and the maximum pedal travel is exponentially decayed to determine the second basic compensation intensity; according to the product of the offset compensation coefficient and the second basic compensation intensity, the second offset compensation intensity of the brake pedal is determined.

The second preset smoothing coefficient may be 1, which is used to characterize the attenuation degree corresponding to the maximum attenuation in the exponential attenuation process. It is understandable that by performing the maximum exponential attenuation on the difference between the minimum pedal stroke and the maximum pedal stroke, a relatively fixed second basic compensation strength can be obtained.

Specifically, the second basic compensation strength of the brake pedal can be expressed by the following formula (12):

(12)

in, is the second basic compensation intensity; is a second preset smoothing coefficient; is the minimum pedal travel; is the maximum pedal travel.

Based on the above formula (12) and formula (10), the second offset compensation strength of the brake pedal can be obtained as shown in the following formula (13):

(13)

in, is the second offset compensation strength.

S720: Reduce the second offset compensation intensity on the target braking intensity to update the target braking intensity.

Optionally, the second offset compensation strength is subtracted from the target braking strength to compensate the target braking strength again to obtain the updated target braking strength. Specifically, based on the above formula (7) and combined with the above formula (13), the updated target braking strength can be expressed by the following formula (14):

(14)

in, is the target braking intensity after being updated again.

It should be noted that, since the second offset compensation strength is reduced from the target braking strength, it is inevitable that the target braking strength after being updated again is less than 0, that is, At this time, in order to ensure that the updated target braking intensity value is meaningful, in this case, the updated target braking intensity is set to 0. That is, if , but .

Furthermore, in another optional embodiment, the target braking intensity can be updated comprehensively based on the aforementioned first deviation compensation intensity and the second offset compensation intensity in this embodiment. Since the compensation value of the second offset compensation intensity is extremely small and can be almost ignored, when considering the maximum braking intensity at 100% travel and the influence of the initial small travel at the starting position, these small changes can be regarded as having no effect.

In summary, based on formulas (8)-(14), the following formula can also be used to comprehensively update the target braking intensity:

(15)

It is worth noting that, since the second offset compensation strength is reduced from the target braking strength, it is inevitable that the target braking strength after being updated again is less than 0, that is, At this time, in order to ensure that the updated target braking intensity value is meaningful, in this case, the updated target braking intensity is set to 0. That is, if ,but .

S730: Perform braking control on the target vehicle according to the updated target braking intensity.

The embodiment of the present application introduces a second offset compensation strength of the brake pedal based on the maximum pedal travel, the current degree of brake weakening and the minimum pedal travel of the brake pedal, and compensates the updated target braking strength based on the second offset compensation strength, thereby ensuring that the braking strength of the target vehicle can be accurately simulated when the brake pedal is at 0% travel, thereby further achieving precise braking control of the target vehicle.

It should be noted that, in order to enable the driver to perceive the failure of the brake system, in the embodiment of the present application, the accuracy of the current brake weakening degree determined is improved by simulating the braking characteristic that the secondary pressurization can increase the brake pressure. That is, it is considered that the brake weakening degree when the brake pedal is stepped on for the second time is related to the brake weakening degree when the brake pedal is stepped on for the last time. Therefore, the first brake weakening degree of the brake pedal under the current friction coefficient can be determined first; further, the current brake weakening degree can be determined based on the braking information in the previous braking behavior process of the current braking behavior.

Exemplarily, the first degree of brake weakening can be determined based on the product of the current friction coefficient and the second preset coefficient as the basis for determining the current degree of weakening. Subsequently, based on whether the current braking behavior is the first braking behavior, combined with the first degree of brake weakening, the current degree of brake weakening of the brake pedal can be differentiated and determined.

In an optional embodiment, if the current braking behavior is the first braking behavior, a smaller value between the first braking weakening degree and the default instantaneous braking weakening degree is selected as the current braking weakening degree of the brake pedal.

The instantaneous brake weakening degree is the magnitude of the associated brake weakening caused by the previous braking behavior, and the default instantaneous brake weakening degree is the preset instantaneous brake weakening degree. It is understandable that since there is no previous braking behavior for the first braking behavior, the default instantaneous brake weakening degree is used to replace the instantaneous brake weakening degree of the previous braking behavior, and the smaller value is selected from the calculated first brake weakening degree and the default instantaneous brake weakening degree as the current brake weakening degree of the brake pedal.

In another optional embodiment, if the current braking behavior is not the first braking behavior, the instantaneous braking weakening degree of the current braking behavior is determined according to the instantaneous braking weakening degree corresponding to the previous braking behavior of the current braking behavior, the historical pedal travel of the previous braking behavior, and the braking interval between the current braking behavior and the previous braking behavior, and the smaller value between the first braking weakening degree and the instantaneous braking weakening degree of the current braking behavior is selected as the current braking weakening degree of the brake pedal. Among them, the instantaneous braking weakening degree corresponding to the previous braking behavior of the current braking behavior is the braking weakening degree of the previous braking behavior; the historical pedal travel of the previous braking behavior is the pedal travel of the previous braking behavior.

Specifically, when the current behavior is not the first braking behavior, the instantaneous braking weakening degree of the current braking behavior can be determined according to the instantaneous braking weakening degree of the previous braking behavior, the influence of the historical pedal travel and the braking interval on the braking weakening degree of the current braking behavior. Further, a smaller value is selected from the first braking weakening degree and the instantaneous braking weakening degree of the current braking behavior as the current braking weakening degree of the brake pedal.

Optionally, in order to ensure the accuracy of the instantaneous brake weakening degree of the current braking behavior, the present application further provides an optional embodiment, in which the step of determining the instantaneous brake weakening degree of the current braking behavior is refined, and the step includes:

S810: Determine an instantaneous brake weakening amplitude according to the product of a historical pedal travel of a previous braking action and a preset pedaling amplitude.

Among them, the instantaneous brake weakening amplitude is the associated brake weakening amplitude caused by the previous braking behavior; the preset pedaling amplitude is the attenuation amplitude of the instantaneous brake weakening degree when the brake pedal is fully stepped on.

Optionally, a curve showing the change of braking intensity with braking stroke under different degrees of braking weakening is shown in FIG4. The horizontal axis x is the braking stroke, and a braking stroke of 0 represents the minimum value of the braking stroke (corresponding to 0%), and a braking stroke of 10 represents the maximum value of the braking stroke (corresponding to 100%); the vertical axis y represents the braking intensity; the black dotted line is the linear change curve of the braking intensity with braking stroke in the existing method, i.e., the reference braking intensity in the above embodiment (refer to the above formula (2)); different solid lines correspond to different degrees of braking weakening (i.e., u in FIG4), and the specific values of the degree of braking weakening are shown in the annotations in FIG4. It can be seen from FIG4 that as the degree of braking weakening gradually increases, the obtained curve deviates more from the curve corresponding to the reference braking intensity.

In addition, it can be seen from FIG4 that after the brake weakening degree is greater than 13, the curve will not change much. Based on this, the preset pedaling amplitude can be set to 6. Specifically, the process of determining the instantaneous brake weakening amplitude according to the product of the historical pedal travel of the previous braking behavior and the preset pedaling amplitude can be expressed by the following formula (16):

(16)

in, is the instantaneous brake weakening amplitude; It is the historical pedal travel of the previous braking action and can be expressed as a percentage.

Of course, the preset pedaling amplitude can also be set to other values, and this application does not impose any limitation on this.

S820, determining an instantaneous braking compensation amplitude according to the product of the braking interval and a preset compensation amplitude.

The instantaneous braking compensation amplitude is the braking compensation amplitude caused by the previous braking behavior. The braking interval is the time length between the current braking behavior and the previous braking behavior; the preset compensation amplitude is the preset amplitude required for compensation per unit time length, which can be set by technicians according to needs or experience, or determined through a large number of tests, and this application does not impose any restrictions on this. In a specific implementation, the preset compensation amplitude can be set to 1.

Optionally, as the time interval between the previous braking action and the current braking action increases, the degree of brake weakening will gradually recover, that is, for every 1 second increase in the braking interval, the degree of brake weakening will decrease by 1 unit. Specifically, according to the product of the braking interval and the preset compensation amplitude, the process of determining the instantaneous braking compensation amplitude can be expressed by the following formula (17):

(17)

in, is the instantaneous braking compensation amplitude; is the braking interval; is a preset compensation amplitude, which may be 1, for example.

S830: Determine the instantaneous braking weakening degree of the current braking behavior according to the instantaneous braking weakening degree, the instantaneous braking weakening amplitude and the instantaneous braking compensation amplitude corresponding to the previous braking behavior.

The instantaneous braking weakening degree is a quantitative degree value of weakening the reference braking intensity determined by the influence of the previous braking behavior.

Optionally, the instantaneous braking weakening degree of the current braking behavior can be calculated based on the functional relationship between the instantaneous braking weakening degree, instantaneous braking weakening amplitude and instantaneous braking compensation amplitude corresponding to the previous braking behavior and the instantaneous braking weakening degree of the current braking behavior.

In order to ensure the accuracy of the determined instantaneous brake weakening degree, the larger value of the target difference and the default brake weakening degree can be selected as the second brake weakening degree; the sum of the second brake weakening degree and the instantaneous brake compensation amplitude is used as the instantaneous brake weakening degree of the current braking behavior. Among them, the target difference is the difference between the instantaneous brake weakening degree corresponding to the previous braking behavior and the instantaneous brake weakening amplitude; the default brake weakening degree is a pre-set brake weakening degree. In the embodiment of the present application, the default brake weakening degree is 0.

Specifically, combined with the above formula (16), the target difference can be expressed by the following formula (18):

(18)

in, is the target difference; It is the instantaneous brake weakening degree corresponding to the previous braking behavior.

Furthermore, the process of selecting the larger value between the target difference and the default brake weakening degree as the second brake weakening degree can be expressed according to the following formula (19):

(19)

in, Indicates the second brake weakening level; 0 indicates the default brake weakening level.

Furthermore, combining the above formula (19) and formula (17), the instantaneous braking weakening degree of the current braking behavior can be expressed by the following formula (20):

(20)

in, It should be noted that, combined with the above formula (4), if , then let .

Optionally, combined with the above formula (8), according to For formula (8) The updated target braking intensity is obtained, which can be specifically expressed by the following formula (21):

(twenty one)

Or optionally, combined with the above formula (14), according to For formula (14) The target braking intensity is updated and obtained, which can be specifically expressed by the following formula (22):

(twenty two)

It should be noted that for the above formula (22), when hour, .

Or optionally, combined with the above formula (15), according to For formula (15) The target braking intensity is updated again, which can be specifically expressed by the following formula (23):

(twenty three)

It should be noted that for the above formula (23), when hour, .

The embodiment of the present application introduces an instantaneous braking weakening amplitude according to the product of the historical pedal travel of the previous braking behavior and the preset pedaling amplitude, and introduces an instantaneous braking compensation amplitude according to the product of the braking interval and the preset compensation amplitude; further, the instantaneous braking weakening degree of the current braking behavior is determined according to the instantaneous braking weakening degree, the instantaneous braking weakening amplitude and the instantaneous braking compensation amplitude corresponding to the previous braking behavior, fully considering the influence of the previous braking behavior on the current braking behavior, compensating for the braking weakening degree, and ensuring the accuracy of the determined instantaneous braking weakening degree of the current braking behavior.

It should be noted that, as can be seen from FIG. 4 in the above embodiment, when the braking intensity exceeds 20%, the slope of the curve of the braking intensity changing with the braking stroke changes significantly, and this change may cause the driver to misjudge the braking performance. Therefore, in order to avoid accidents caused by the driver's misjudgment, once the braking intensity is detected to exceed 20%, the braking system in the target vehicle will activate the sound and light alarm mechanism to warn the driver that the target vehicle is in an abnormal state where the braking system is connected to increase the braking force, thereby guiding the driver to take necessary intervention measures in time, such as reducing the speed of the vehicle in time or reducing the frequency of stepping on the brake pedal.

Furthermore, as shown in FIG5 , the curve of the change of the braking intensity and the pedal stroke of the present application is compared with the curve of the change of the braking intensity and the pedal stroke of the prior art. Among them, the horizontal axis x represents the pedal stroke (range is 0-10), and the vertical axis y represents the braking intensity (range is 0-10, corresponding to 0%-100% of the maximum braking intensity); the black solid line (i.e., curve 1) is the curve of the change of the braking intensity and the pedal stroke in the prior art without considering the braking force decay; the black dotted line (i.e., curve 2) is the curve of the change of the braking intensity and the pedal stroke of the vehicle control method provided in the embodiment of the present application; the gray dotted line (i.e., curve 3) is the deviation value after weakening correction. It can be seen from FIG5 that the control response of the pedal stroke in the front section of curve 2 will be moderately slowed down, and the subsequent stage will gradually return to the expected braking force performance, that is, compared with the prior art, the vehicle control method provided in the embodiment of the present application can more accurately simulate the braking force decay state of the target vehicle and improve the driver's perception of braking force decay.

Based on the technical solutions of the above embodiments, the present application also provides an optional embodiment, in which the vehicle control process is described in detail.

Referring to the vehicle control method shown in FIG6 , the method includes:

S901, obtaining the current wheel speed of the wheels of the target vehicle under the current braking behavior, the current piston pressure of the brake piston, and the current pedal travel of the brake pedal.

S902: Determine a current friction coefficient of a friction brake component in the target vehicle according to the current wheel speed and the current piston pressure.

S903: Determine a reference braking intensity of the brake pedal according to the product of the current pedal travel and the first preset coefficient.

S904: Determine the current brake weakening degree of the brake pedal according to the product of the current friction coefficient and the second preset coefficient.

S905 , based on a preset exponential function and according to a first preset smoothing coefficient, exponentially decay the difference between the current pedal travel and the current brake weakening degree to determine a current decay compensation coefficient.

S906: Determine a target braking intensity of the brake pedal according to the product of the current fade compensation coefficient and the reference braking intensity.

S907 , based on a preset exponential function and according to a first preset smoothing coefficient, exponentially decay the difference between the maximum pedal travel and the current brake weakening degree to obtain an offset compensation coefficient.

S908 , based on a preset exponential function and according to a second preset smoothing coefficient, exponentially decay the difference between the current pedal stroke and the maximum pedal stroke to determine a first basic compensation intensity.

The second preset smoothing coefficient is 1.

S909: Determine a first offset compensation strength of the brake pedal according to the product of the offset compensation coefficient and the first basic compensation strength.

S910: Accumulate the first offset compensation intensity on the target braking intensity to update the target braking intensity.

S911, determining a second offset compensation strength of the brake pedal according to the maximum pedal travel, the current brake weakening degree and the minimum pedal travel of the brake pedal.

Optionally, based on a preset exponential function, the difference between the minimum pedal stroke and the current pedal stroke is exponentially decayed according to a second preset smoothing coefficient to determine a second basic compensation strength; the second offset compensation strength of the brake pedal is determined according to the product of the offset compensation coefficient and the second basic compensation strength.

S912: Reduce the second offset compensation intensity based on the updated target braking intensity to update the target braking intensity again.

S913, performing braking control on the target vehicle according to the target braking intensity that has been updated again.

The specific process of S901-S913 above can refer to the description of the above method embodiment, and its implementation principle and technical effect are similar, which will not be repeated here.

It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

Based on the same inventive concept, the embodiment of the present application also provides a vehicle control device for implementing the vehicle control method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more vehicle control device embodiments provided below can refer to the limitations on the vehicle control method above, and will not be repeated here.

In an exemplary embodiment, as shown in FIG. 7 , a vehicle control device is provided, including: an information acquisition module 1010, a coefficient determination module 1020, an intensity determination module 1030 and a braking control module 1040, wherein:

The information acquisition module 1010 is used to acquire the current wheel speed of the wheels in the target vehicle, the current piston pressure of the brake piston and the current pedal travel of the brake pedal under the current braking behavior.

The coefficient determination module 1020 is used to determine the current friction coefficient of the friction brake in the target vehicle according to the current wheel speed and the current piston pressure.

The strength determination module 1030 is used to determine the target braking strength of the brake pedal in the target vehicle according to the current friction coefficient and the current pedal travel when the current friction coefficient meets the braking force attenuation condition.

The brake control module 1040 is used to perform brake control on the target vehicle according to the target brake intensity.

In one embodiment, the strength determination module 1030 includes: a first determination unit, configured to determine a reference braking strength of the brake pedal under a current pedal stroke; a coefficient determination unit, configured to determine a current decay compensation coefficient of the brake pedal according to a current friction coefficient and a current pedal stroke; and a second determination unit, configured to determine a target braking strength of the brake pedal according to a product of the current decay compensation coefficient and the reference braking strength.

In one embodiment, the coefficient determination unit includes: a degree determination slave unit, which is used to determine the current brake weakening degree of the brake pedal under the current friction coefficient. The coefficient determination slave unit is used to perform exponential decay on the difference between the current pedal stroke and the current brake weakening degree based on a preset exponential function and a first preset smoothing coefficient to determine the current decay compensation coefficient.

In one embodiment, the brake control module 1040 includes: a first compensation determination unit, used to determine a first offset compensation strength of the brake pedal according to a current brake weakening degree, a current pedal stroke, and a maximum pedal stroke of the brake pedal; a first strength updating unit, used to add the first offset compensation strength to a target brake strength to update the target brake strength; and a first brake control unit, used to perform brake control on a target vehicle according to the updated target brake strength.

In one embodiment, the compensation determination unit is specifically used to: based on a preset exponential function, according to a second preset smoothing coefficient, exponentially decay the difference between the current pedal stroke and the maximum pedal stroke to determine a first basic compensation strength; wherein the second preset smoothing coefficient is 1; based on a preset exponential function, according to a first preset smoothing parameter, exponentially decay the difference between the maximum pedal stroke and the current degree of brake weakening to obtain an offset compensation coefficient; and determine the first offset compensation strength of the brake pedal according to the product of the offset compensation coefficient and the first basic compensation strength.

In one embodiment, the strength determination module 1030 includes: a second compensation strength determination unit, configured to determine a second offset compensation strength of the brake pedal according to a maximum pedal stroke, a current brake weakening degree, and a minimum pedal stroke of the brake pedal; a second strength update unit, configured to reduce the second offset compensation strength on the target braking strength to update the target braking strength; and a second braking control unit, configured to perform braking control on the target vehicle according to the updated target braking strength.

In one embodiment, the second compensation strength determination unit is specifically used to: based on a preset exponential function, according to a second preset smoothing coefficient, exponentially decay the difference between the minimum pedal stroke and the current pedal stroke to determine the second basic compensation strength; based on a preset exponential function, according to a first preset smoothing coefficient, exponentially decay the difference between the maximum pedal stroke and the current degree of brake weakening to obtain an offset compensation coefficient; determine the second offset compensation strength of the brake pedal according to the product of the offset compensation coefficient and the second basic compensation strength.

In one embodiment, the degree determination slave unit includes: a determination subunit, which is used to determine the first brake weakening degree of the brake pedal under the current friction coefficient. A first selection subunit, which is used to select the smaller value between the first brake weakening degree and the default instantaneous brake weakening degree as the current brake weakening degree of the brake pedal if the current braking behavior is the first braking behavior. A second selection subunit, which is used to determine the instantaneous brake weakening degree of the current braking behavior according to the instantaneous brake weakening degree corresponding to the previous braking behavior of the current braking behavior, the historical pedal stroke of the previous braking behavior, and the braking interval between the current braking behavior and the previous braking behavior if the current braking behavior is not the first braking behavior, and select the smaller value between the first brake weakening degree and the instantaneous brake weakening degree of the current braking behavior as the current brake weakening degree of the brake pedal.

In one embodiment, the second selection subunit is specifically used to: determine the instantaneous braking weakening amplitude based on the product of the historical pedal travel of the previous braking behavior and the preset pedaling amplitude; and determine the instantaneous braking compensation amplitude based on the product of the braking interval and the preset compensation amplitude; determine the instantaneous braking weakening degree of the current braking behavior based on the instantaneous braking weakening degree, instantaneous braking weakening amplitude and instantaneous braking compensation amplitude corresponding to the previous braking behavior.

In one embodiment, the second selection subunit is also used to: select the larger value between the target difference and the default braking weakening degree as the second braking weakening degree; the target difference is the difference between the instantaneous braking weakening degree and the instantaneous braking weakening amplitude corresponding to the previous braking behavior; and use the sum of the second braking weakening degree and the instantaneous braking compensation amplitude as the instantaneous braking weakening degree of the current braking behavior.

Each module in the above vehicle control device can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each module.

In an exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be shown in FIG8. The computer device includes a processor, a memory, an input/output interface (Input/Output, referred to as I/O) and a communication interface. The processor, the memory and the input/output interface are connected via a system bus, and the communication interface is connected to the system bus via the input/output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input/output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a vehicle control method is implemented.

Those skilled in the art will understand that the structure shown in FIG. 8 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps of the above-mentioned vehicle control method when executing the computer program.

In an optional embodiment, the present application also provides a vehicle, in which the computer device shown in FIG. 8 is arranged.

In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned vehicle control method are implemented.

In one embodiment, a computer program product is provided, comprising a computer program, which implements the steps of the above vehicle control method when executed by a processor.

It should be noted that the data involved in this application (including but not limited to data used for analysis, storage, display, etc.) are all information and data fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims (12)

1. A vehicle control method, characterized in that the method comprises:

Acquiring the current wheel speed of a wheel in a target vehicle under the current braking action, the current piston pressure of a braking piston and the current pedal stroke of a braking pedal;

determining a current coefficient of friction of a friction brake in the target vehicle based on the current wheel speed and the current piston pressure;

determining a target brake strength of a brake pedal in the target vehicle according to the current friction coefficient and the current pedal travel under the condition that the current friction coefficient meets a brake force attenuation condition;

and according to the target braking intensity, performing braking control on the target vehicle.

2. The method of claim 1, wherein said determining a target brake strength of a brake pedal in the target vehicle based on the current coefficient of friction and the current pedal travel comprises:

Determining a reference brake strength of the brake pedal under a current pedal stroke;

determining a current fade compensation coefficient of the brake pedal according to the current friction coefficient and the current pedal travel;

And determining the target braking intensity of the brake pedal according to the product of the current fading compensation coefficient and the reference braking intensity.

3. The method of claim 2, wherein said determining a current fade compensation coefficient for said brake pedal based on said current coefficient of friction and said current pedal travel comprises:

determining a current brake weakness of the brake pedal at a current coefficient of friction;

And based on a preset exponential function, according to a first preset smoothing coefficient, carrying out exponential decay on the difference between the current pedal stroke and the current braking weakening degree, and determining a current decay compensation coefficient.

4. A method according to claim 3, wherein said brake control of said target vehicle in accordance with said target brake strength comprises:

Determining a first offset compensation strength of the brake pedal according to the current brake weakness, the current pedal stroke and a maximum pedal stroke of the brake pedal;

accumulating the first offset compensation intensity over the target brake intensity to update the target brake intensity;

and according to the updated target braking intensity, performing braking control on the target vehicle.

5. The method of claim 4, wherein said determining a first offset compensation strength of said brake pedal based on said current brake fade, said current pedal travel, and a maximum pedal travel of said brake pedal comprises:

Based on the preset exponential function, carrying out exponential decay on the difference value between the current pedal stroke and the maximum pedal stroke according to a second preset smoothing coefficient, and determining a first basic compensation intensity; wherein the second preset smoothing coefficient is 1;

based on the preset exponential function, according to the first preset smoothing coefficient, carrying out exponential decay on the difference between the maximum pedal stroke and the current braking weakening degree to obtain an offset compensation coefficient;

a first offset compensation intensity of the brake pedal is determined based on a product of the offset compensation coefficient and the first base compensation intensity.

6. The method according to any one of claims 3 to 5, wherein the brake control of the target vehicle according to the target brake intensity includes:

Determining a second offset compensation strength of the brake pedal based on the maximum pedal travel, the current brake weakness, and a minimum pedal travel of the brake pedal;

Reducing the second offset compensation intensity on the target brake intensity to update the target brake intensity;

and according to the updated target braking intensity, performing braking control on the target vehicle.

7. The method of claim 6, wherein said determining a second offset compensation strength of said brake pedal based on said maximum pedal travel, said current brake fade, and a minimum pedal travel of said brake pedal comprises:

based on the preset exponential function, according to the second preset smoothing coefficient, carrying out exponential decay on the difference value between the minimum pedal stroke and the maximum pedal stroke, and determining a second basic compensation intensity;

based on the preset exponential function, according to the first preset smoothing coefficient, carrying out exponential decay on the difference between the maximum pedal stroke and the current braking weakening degree to obtain an offset compensation coefficient;

And determining a second offset compensation intensity of the brake pedal according to the product of the offset compensation coefficient and the second basic compensation intensity.

8. The method of any one of claims 3-5, wherein said determining a current brake weakness of the brake pedal at a current coefficient of friction comprises:

determining a first brake weakness of the brake pedal at the current coefficient of friction;

If the current braking behavior is a first braking behavior, selecting the smaller value of the first braking weakening degree and a default instantaneous braking weakening degree as the current braking weakening degree of the brake pedal;

If the current braking behavior is a non-first braking behavior, determining the instantaneous braking weakening degree of the current braking behavior according to the instantaneous braking weakening degree corresponding to the previous braking behavior of the current braking behavior, the historical pedal travel of the previous braking behavior and the braking interval between the current braking behavior and the previous braking behavior, and selecting the smaller value of the instantaneous braking weakening degree of the current braking behavior and the first braking weakening degree as the current braking weakening degree of the brake pedal.

9. The method of claim 8, wherein the determining the instantaneous brake weakness of the current braking action based on the corresponding instantaneous brake weakness of the previous braking action of the current braking action, the historical pedal travel of the previous braking action, and the braking interval between the current braking action and the previous braking action comprises:

Determining an instantaneous braking weakening amplitude according to the product of the historical pedal travel of the previous braking action and a preset stepping amplitude; and

Determining an instantaneous braking compensation amplitude according to the product of the braking interval and a preset compensation amplitude;

And determining the instantaneous braking weakening degree of the current braking action according to the instantaneous braking weakening degree, the instantaneous braking weakening degree and the instantaneous braking compensation degree corresponding to the previous braking action.

10. The method of claim 9, wherein said determining the instantaneous brake weakness of the current braking action based on the corresponding instantaneous brake weakness of the previous braking action, the instantaneous brake weakness and the instantaneous brake compensation amplitude comprises:

selecting a larger value of the target difference value and the default brake weakening degree as a second brake weakening degree; the target difference value is the difference value between the instantaneous braking weakening degree corresponding to the previous braking action and the instantaneous braking weakening amplitude;

And taking the sum value between the second braking weakening degree and the instantaneous braking compensation amplitude as the instantaneous braking weakening degree of the current braking action.

11. A vehicle control apparatus, characterized in that the apparatus comprises:

the information acquisition module is used for acquiring the current wheel speed of the wheels in the target vehicle, the current piston pressure of the brake piston and the current pedal stroke of the brake pedal under the current braking action;

The coefficient determining module is used for determining the current friction coefficient of the friction braking piece in the target vehicle according to the current wheel speed and the current piston pressure;

the intensity determining module is used for determining target braking intensity of a brake pedal in the target vehicle according to the current friction coefficient and the current pedal stroke under the condition that the current friction coefficient meets a braking force attenuation condition;

and the brake control module is used for carrying out brake control on the target vehicle according to the target brake intensity.

12. A vehicle, characterized in that it is provided with a device for implementing the method according to any one of claims 1-10.