Brake control method, controller, medium, product, and vehicle

Abstract

The application relates to a brake control method, a controller, a medium, a product and a vehicle. In the case that the vehicle has a brake demand, a brake torque curve is obtained, wherein the brake torque curve comprises at least two brake torques with different brake sequences and switching control parameters of adjacent brake torques, the brake torque with a later brake sequence is smaller than the brake torque with an earlier brake sequence; and the brake movement of the vehicle is controlled based on the brake torque in the brake torque curve and the switching control parameter. Therefore, the brake movement of the vehicle is controlled by adopting the brake torque curve comprising multiple brake torques with different sizes and different brake sequences, so that the user experience is improved by reducing the pitching impact of the vehicle when stopping.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of brake control, in particular to a brake control method, a controller, a medium, a product and a vehicle. BACKGROUND

[0002] When the existing vehicle brakes, due to the action of the ground longitudinal force, the elastic elements in the automobile suspension are constantly compressed or stretched, so that the body produces corresponding pitching motion and longitudinal impact, which has adverse effects on the riding comfort of passengers and the steering stability of drivers.

[0003] The existing brake mode has a large amplitude of pitching impact due to a large ground longitudinal force, which affects the user experience. SUMMARY

[0004] The embodiments of the present application provide a brake control method, a controller, a storage medium, a computer program product and a vehicle, by adopting a brake torque curve containing multiple brake torques with different sizes and different brake sequences, the brake motion of the vehicle is controlled to reduce the pitching impact of the vehicle when stopping and improve the user experience.

[0005] The embodiments of the present application provide a brake control method, comprising:

[0006] In the case that the vehicle has a brake demand, a brake torque curve is obtained, wherein the brake torque curve includes at least two brake torques with brake sequences and switching control parameters of adjacent brake torques, the brake torque with a later brake sequence is smaller than the brake torque with an earlier brake sequence;

[0007] Based on the brake torque in the brake torque curve and the switching control parameter, the brake motion of the vehicle is controlled.

[0008] In addition, the embodiments of the present application also provide a controller, which includes one or more processors and a memory, the above-mentioned memory stores a computer program, and the above-mentioned processor is used to run the computer program in the above-mentioned memory to realize the brake control method provided by the embodiments of the present application.

[0009] In addition, the embodiments of the present application also provide a storage medium, which stores a computer program, when the above-mentioned computer program runs on the controller, the above-mentioned computer program is used to make the controller execute any brake control method provided by the embodiments of the present application.

[0010] In addition, the embodiments of the present application also provide a computer program product, which includes a computer program or instructions, when the computer program or instructions are executed by a processor, any brake control method provided by the embodiments of the present application is realized.

[0011] In addition, the embodiment of the present application also provides a vehicle comprising the controller.

[0012] In the embodiment of the present application, the braking torque curve is obtained when the vehicle has braking demand, wherein the braking torque curve comprises at least two braking torques with different braking sequences and switching control parameters of adjacent braking torques, and the braking torque with later braking sequence is smaller than the braking torque with earlier braking sequence; and the braking movement of the vehicle is controlled based on the braking torque in the braking torque curve and the switching control parameter. Based on this, the braking movement of the vehicle is controlled by adopting the braking torque curve comprising multiple braking torques with different sizes and different braking sequences, so as to reduce the braking torque to gently reduce the pitching impact of the vehicle when stopping, and improve the user experience. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0014] Figure 1 is an implementation environment scene diagram of the braking control method provided in the embodiment of the present application;

[0015] Figure 2 is a flowchart of the braking control method provided in the embodiment of the present application;

[0016] Figure 3 is a braking torque curve diagram of the braking control method provided in the embodiment of the present application;

[0017] Figure 4 is a pitch angular velocity simulation comparison diagram of different candidate braking torque curves and a fixed braking torque curve provided in the embodiment of the present application;

[0018] Figure 5 is an architecture diagram of a vehicle body-suspension-tire coupling system provided in the embodiment of the present application;

[0019] Figure 6 is a schematic diagram of a half-active suspension vehicle dynamics model provided in the embodiment of the present application;

[0020] Figure 7 is a C-class road noise disturbance input simulation diagram provided in the embodiment of the present application;

[0021] Figure 8 is a specific flowchart of the braking control method provided in the embodiment of the present application;

[0022] Figure 9 : is a schematic diagram of the simulation of the front and rear wheel braking torque input curves provided in an embodiment of the present application;

[0023] Figure 10 : This is a comparison diagram of simulated pitch angular velocity of the active suspension without a controller, with a PID controller, and with a fuzzy PID controller, provided in the embodiments of the present application;

[0024] Figure 11 This is a comparison chart of pitch angular velocity simulations without pitch motion adjustment, using only active suspension adjustment, using only comfort braking torque curve adjustment, and using combined control adjustment, provided in the embodiments of the present application;

[0025] Figure 12 This is a diagram of a braking strategy architecture for different road adhesion coefficients provided in an embodiment of the present application;

[0026] Figure 13 It is a schematic diagram of the structure of the controller provided in the embodiment of the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0028] In addition, the term "a plurality of" in the embodiments of the present application refers to two or more than two. The terms "first" and "second" in the embodiments of the present application are used to distinguish descriptions and should not be understood to imply relative importance.

[0029] Research has found that when existing vehicles brake, the longitudinal ground force causes the elastic elements in the vehicle's suspension to continuously compress or expand, resulting in corresponding pitch motion and longitudinal impact on the vehicle body. This negatively impacts both passenger comfort and driver stability. In particular, when the amplitude of the vehicle's pitch angular velocity is excessive, passengers are prone to symptoms such as dizziness and nausea. Adjusting the dynamic characteristics of the vehicle's pitch motion is currently an important research direction for improving passenger comfort.

[0030] To solve the above problems, embodiments of the present application provide a braking control method, a controller, a storage medium, a computer program product, and a vehicle. The braking control method can be applied to a controller, which can be a server or a terminal.

[0031] The server can be a stand-alone physical server, a server cluster composed of multiple physical servers, or a distributed system, and can also be a cloud server providing cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content delivery network (CDN), and basic cloud computing services such as big data and artificial intelligence platforms.

[0032] The terminal can be a smartphone, a tablet computer, a notebook computer, a desktop computer, a smart speaker, a smart watch, and the like, but is not limited thereto. The terminal and the server can be directly or indirectly connected through wired or wireless communication, which is not limited in the present application.

[0033] Please refer to Figure 1 For example, the brake control method is applied in a controller, Figure 1 The implementation scenario of the brake control method provided by the embodiments of the present application is shown in the figure, wherein the controller can be a terminal device. In the case that the vehicle has a braking demand, a brake torque curve is obtained, wherein the brake torque curve includes at least two brake torques with different braking sequences and switching control parameters of adjacent brake torques, and the brake torque with a later braking sequence is smaller than the brake torque with an earlier braking sequence. The braking movement of the vehicle is controlled based on the brake torque in the brake torque curve and the switching control parameter. Based on this, the braking movement of the vehicle is controlled by using a brake torque curve containing multiple brake torques with different sizes and different braking sequences, so as to reduce the brake torque to reduce the pitching impact of the vehicle when parking, and improve the user experience.

[0034] It should be noted that Figure 1 The implementation environment scenario of the brake control method shown in the figure is only an example, and the implementation environment scenario of the brake control method described in the embodiments of the present application is used to more clearly illustrate the technical solutions of the embodiments of the present application, and does not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art can know that, with the evolution of data processing and the emergence of new business scenarios, the technical solutions provided by the present application are also applicable to similar technical problems.

[0035] The scheme provided by the embodiments of the present application is described in detail through the following embodiments. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments.

[0036] This embodiment will be described from the perspective of the brake control method, which can be applied in a controller. The controller can be a terminal and / or a server, which is not limited in the present application.

[0037] Please refer to Figure 2, Figure 2 is a flowchart of a brake control method provided by an embodiment of the present application. The brake control method can include the following steps S101-S102:

[0038] S101, in the case where the vehicle has a brake demand, obtaining a brake torque curve, wherein the brake torque curve includes at least two brake torques with a brake sequence and switching control parameters of adjacent brake torques, the brake torque after the brake sequence is smaller than the brake torque before the brake sequence.

[0039] wherein the vehicle refers to a vehicle that needs to be controlled in braking motion. The brake demand refers to the need of the vehicle for brake control.

[0040] wherein the brake torque curve is used to describe the curve of the relationship between the brake torque and a parameter during the braking process of the vehicle. The parameter can include but is not limited to time, brake pressure, vehicle speed, brake temperature, etc. The specific parameter can be adjusted according to the actual situation, and the embodiment of the present application does not make any limitation.

[0041] Exemplarily, please refer to Figure 3 , Figure 3 is a schematic diagram of the brake torque curve provided by the embodiment of the present application. As shown in Figure 3 , the brake torque curve is used to describe the change of the brake torque with time during the braking process of the vehicle.

[0042] wherein the number of brake torques contained in the brake torque curve can be adjusted according to the actual situation, and the embodiment of the present application does not make any limitation. For example, the brake torque curve includes a first brake torque and a second brake torque, and the brake sequence of the first brake torque is before the brake sequence of the second brake torque. For another example, the brake torque curve includes three brake torques A, B and C, the brake sequence of the brake torque A is before the brake sequence of the brake torque B, and the brake sequence of the brake torque B is before the brake sequence of the brake torque C.

[0043] wherein the brake torque refers to the torque exerted by the brake system on the wheels or transmission shaft of the vehicle, which is used to hinder the motion of the vehicle and make the vehicle decelerate or stop.

[0044] wherein the switching control parameter is used to control the switching from the brake torque before the brake sequence to the brake torque after the brake sequence. The number of switching control parameters is related to the number of brake torques contained in the brake torque curve. For example, when the brake torque curve contains three brake torques, the number of switching control parameters is two.

[0045] It should be noted that the embodiment of the present application changes the fixed braking torque curve in the past. In the case of meeting the switching control parameter, the braking system changes the braking torque according to the braking torque curve, controls the braking movement of the vehicle with smaller braking torque, reduces the braking torque to gently impact the pitch of the vehicle when parking, and improves the user experience.

[0046] S102, control the braking movement of the vehicle based on the braking torque in the braking torque curve and the switching control parameter.

[0047] Therefore, the braking control method provided by the embodiment of the present application, by acquiring the braking torque curve when the vehicle has braking demand, wherein the braking torque curve includes at least two braking torques with braking sequence and switching control parameters of adjacent braking torques, the braking torque after the braking sequence is smaller than the braking torque before the braking sequence; based on the braking torque in the braking torque curve and the switching control parameter, the braking movement of the vehicle is controlled. Based on this, by adopting the braking torque curve containing multiple braking torques with different sizes and different braking sequences, the braking movement of the vehicle is controlled to reduce the braking torque to gently impact the pitch of the vehicle when parking, and improve the user experience.

[0048] It should be noted that the switching control parameter can include various types of data, and its specific content can be adjusted according to the braking torque curve, which is not limited by the embodiment of the present application. For example, when the braking torque curve is the change relationship between the braking torque and the time, the switching control parameter can include the torque drop starting time and the torque drop ending time. For example, t1 in the formula (1) is the torque drop starting time, and t2 is the torque drop ending time. Figure 3 For another example, when the braking torque curve is the change relationship between the braking torque and the vehicle speed, the switching control parameter can include the preset vehicle speed to which the vehicle speed needs to be reduced when the braking torque switching needs to be performed.

[0049] In some embodiments, the above-mentioned switching control parameter includes a switching starting condition.

[0050] The switching starting condition refers to the condition for triggering the start of switching the braking torque.

[0051] The above-mentioned switching starting condition includes that the vehicle speed is reduced to a preset vehicle speed, and / or the braking time of controlling the braking movement of the vehicle based on the braking torque reaches the torque drop starting time.

[0052] When the braking torque curve includes a first braking torque and a second braking torque, the braking sequence of the first braking torque is before the braking sequence of the second braking torque, and the switching starting condition indicates switching from the first braking torque to the second braking torque, the process of controlling the braking motion of the vehicle based on the braking torque in the braking torque curve and the switching control parameter can include: controlling the braking motion of the vehicle based on the first braking torque; in the case where the switching starting condition is met, controlling the switching from the first braking torque to the second braking torque based on the switching control parameter to continue controlling the braking motion of the vehicle.

[0053] In some embodiments, the switching control parameter further includes a torque drop speed.

[0054] Based on this, the process of controlling the switching from the first braking torque to the second braking torque based on the switching control parameter to continue controlling the braking motion of the vehicle can include: controlling the reduction of the braking torque of the vehicle from the first braking torque to the second braking torque according to the torque drop speed; and continuing to control the braking motion of the vehicle based on the second braking torque.

[0055] In some embodiments, the switching control parameter further includes a torque drop end time, the torque drop end time being used to indicate an end time of the reduction of the braking torque of the vehicle, and the braking torque of the vehicle is the second braking torque at the torque drop end time.

[0056] In some embodiments, the process of obtaining the braking torque curve in the case where the vehicle has a braking demand can include the following steps:

[0057] In the case where the vehicle has a braking demand, predicting a deceleration curve and a pitch angular velocity curve of the vehicle in the braking process;

[0058] According to the pitch angular velocity curve, determining an optimization target required for generating the braking torque curve, and according to the deceleration curve, determining a constraint condition required for generating the braking torque curve;

[0059] According to the optimization target and the constraint condition, determining the braking torque curve.

[0060] Wherein, the deceleration curve is used to describe the change relationship between the vehicle speed and the time in the braking process of the vehicle.

[0061] Wherein, the pitch angular velocity curve is used to describe the change relationship between the pitch angular velocity and the time in the braking process of the vehicle.

[0062] Wherein, the optimization target is determined based on the peak value and the valley value of the pitch angular velocity curve.

[0063] Wherein, the constraint condition includes a braking torque range, a braking distance range and a parking time determined based on the deceleration curve.

[0064] The braking torque range is used to indicate a range of the braking torque that can be adjusted. The braking torque range includes a minimum braking torque and a maximum braking torque.

[0065] The braking distance range is used to indicate a distance traveled by the vehicle from when the braking is started to when the vehicle is completely stopped. The braking distance range includes a minimum braking distance and a maximum braking torque.

[0066] The parking time indicates time information when the vehicle is parked based on the braking torque curve.

[0067] In some embodiments, the process of determining the constraint condition required for generating the braking torque curve according to the deceleration curve can include determining the constraint condition according to the deceleration curve and an environmental parameter of an environment in which the vehicle is located.

[0068] The environmental parameter includes a road adhesion coefficient.

[0069] Based on this, the constraint condition can further include a braking torque range, a braking distance range, and a parking time determined based on the road adhesion coefficient and the deceleration curve.

[0070] In some embodiments, the process of predicting the deceleration curve and the pitch angular velocity curve of the vehicle during the braking process can include setting an initial adjustment parameter for generating the braking torque curve according to an initial braking torque when the vehicle has a braking demand, the initial adjustment parameter including the initial braking torque, at least one braking torque after the initial braking torque in the braking sequence, and a switching control parameter between adjacent braking torques; and predicting the deceleration curve and the pitch angular velocity curve of the vehicle during the braking process based on the initial adjustment parameter.

[0071] The initial braking torque refers to a braking torque determined when the vehicle has a braking demand.

[0072] For example, the braking torque curve includes a first braking torque and a second braking torque, and the braking sequence of the first braking torque is before the braking sequence of the second braking torque. Based on this, the initial braking torque is the first braking torque. For another example, the braking torque curve includes three braking torques, a braking torque A, a braking torque B, and a braking torque C, the braking sequence of the braking torque A is before the braking sequence of the braking torque B, and the braking sequence of the braking torque B is before the braking sequence of the braking torque C. Based on this, the initial braking torque is the braking torque A.

[0073] The initial braking torque is determined based on a pedal depth of the vehicle and a preset correspondence between a preset pedal depth and a preset braking torque.

[0074] The initial adjustment parameter refers to a parameter set for adjusting the braking torque curve for generating the braking torque curve.

[0075] Based on this, in some embodiments, the process of determining the braking torque curve according to the optimization target and the constraint condition can include: based on the initial adjustment parameter, the optimization target and the constraint condition, constructing a plurality of candidate braking torque curves, wherein the adjustment parameters of different candidate braking torque curves are different; performing parameter optimization processing on the plurality of candidate braking torque curves, and taking the candidate braking torque curve obtained by optimization as the braking torque curve.

[0076] In order to facilitate understanding of the above-mentioned scheme, the braking torque curve shown in Figure 3 is taken as an example for explanation and description.

[0077] As shown in Figure 3 , T b1 is the initial braking torque, T b2 is the parking braking torque, t1 is the starting time of the braking torque drop, t2 is the ending time of the braking torque drop, and t3 is the parking time. T b1 is generally determined according to the depth of the brake pedal stepped by the driver. According to the above-mentioned parameters, the initial adjustment parameters (T b1 , T b2 , t1, t2, t3) for generating the braking torque curve are set.

[0078] After the initial adjustment parameters are set, the deceleration curve and the pitch angular velocity curve of the vehicle in the braking process are predicted based on the initial adjustment parameters.

[0079] It should be noted that a plurality of candidate braking torque curves are constructed based on the initial adjustment parameter, the optimization target and the constraint condition. The adjustment parameters corresponding to different candidate braking torque curves are different. For each candidate braking torque curve, the corresponding deceleration curve and pitch angular velocity curve of the vehicle in the braking process are predicted based on the adjustment parameter corresponding to the candidate braking torque curve.

[0080] The simulation results of the pitch angular velocity curves obtained by different candidate braking torque curves can be referred to Figure 4 . Through Figure 4It is found that due to the influence of the two groups of independent ground longitudinal force inputs of slope descending and vehicle parking, the peak and valley superimposed phenomenon of the pitch angular velocity curve predicted by different braking torque curves occurs when the vehicle brakes, and according to the phenomenon, the pitch angular velocity curve peak and valley is taken as an optimization target, the braking distance increase, the parking time and the minimum braking torque are taken as constraint conditions, a plurality of candidate braking torque curves with different adjustment parameters can be designed for simulation, and the GA genetic algorithm is used to optimize the parameters from the plurality of candidate braking torque curves, so that the optimal braking torque curve adjustment parameter can be solved, and the optimal braking torque curve is taken as the braking torque curve used for controlling the vehicle braking motion in the embodiment of the application.

[0081] It should be noted that, from Figure 4 It can be known from the displayed pitch angular velocity curve simulation result that the pitch angular velocity oscillation amplitude during the parking stage is greatly improved and the pitch angular velocity compensation effect is significantly improved after the vehicle braking motion is controlled by using the candidate braking torque curve. By comparing the candidate braking torque curves, it can be found that the optimal braking torque curve based on the genetic algorithm is the candidate braking torque curve 1, and the comprehensive performance of the candidate braking torque curve 1 is the best. Through the adjustment of the curve, the peak and valley values of the pitch angular velocity during the braking stage are reduced by more than 60%, the pitch angle is also reduced by more than 60%, and the braking distance increase is not more than 0.15 m, which effectively improves the ride comfort.

[0082] Therefore, compared with the existing vehicle braking, after the driver steps on the brake pedal, the braking torque rises to a fixed value until the braking ends, and the ground longitudinal force is large, which makes the front and rear suspension compression or extension amount large when parking, thereby generating a pitch impact with a large amplitude, causing the discomfort of passengers. The comfort braking torque curve (i.e. the braking torque curve mentioned in the embodiment of the application) is proposed, so that the braking torque of the brake disc can be actively reduced to a calculated value after the vehicle speed decreases to a certain threshold. Based on the above content, not only can the ground longitudinal braking force during the braking and parking stage be reduced to reduce the pitch angular velocity amplitude of the parking impact, but also a slope excitation can be introduced to the vehicle body pitch system in advance, the slope excitation response and the parking pitch impact response are superimposed and compensated with each other, and under reasonable design, the maximum amplitude of the pitch angular velocity at the end of braking can be greatly reduced, and the braking distance is not increased too much.

[0083] In some embodiments, the vehicle is configured with a braking analysis model.

[0084] The braking analysis model refers to a model for analyzing the braking motion process of the vehicle.

[0085] Based on this, the process of predicting the deceleration curve and the pitch angular velocity curve of the vehicle during braking based on the initial adjustment parameter can include: predicting, by the braking analysis model, the vehicle speed information and the pitch angular velocity information of the vehicle during braking based on the initial adjustment parameter and the initial vehicle speed of the vehicle in the case of having braking demand; constructing the deceleration curve according to the multiple vehicle speeds with the sequential order contained in the vehicle speed information; and constructing the pitch angular velocity curve according to the multiple pitch angular velocities with the sequential order contained in the pitch angular velocity information.

[0086] In particular, the braking analysis model includes a tire model and a target dynamics model, wherein the target dynamics model is determined based on at least a dynamics model of the vehicle and a suspension model of the vehicle.

[0087] Based on this, the process of predicting, by the braking analysis model, the vehicle speed information and the pitch angular velocity information of the vehicle during braking based on the initial adjustment parameter and the initial vehicle speed of the vehicle in the case of having braking demand includes: predicting, by the tire model and the target dynamics model, the vehicle speed information and the pitch angular velocity information of the vehicle during braking based on the initial adjustment parameter and the initial vehicle speed of the vehicle in the case of having braking demand.

[0088] In some embodiments, the process of predicting the vehicle speed information of the vehicle during braking includes: determining, by the tire model, the ground longitudinal force based on the initial vehicle speed and the initial adjustment parameter; updating the vehicle speed based on the ground longitudinal force and a preset corresponding relationship between the preset tire ground longitudinal force and the preset vehicle speed; and determining a new ground longitudinal force based on the updated vehicle speed and the initial adjustment parameter, and continuing to perform the step of updating the vehicle speed based on the ground longitudinal force and the preset corresponding relationship between the preset tire ground longitudinal force and the preset vehicle speed to obtain the vehicle speed information.

[0089] In particular, the process of determining, by the tire model, the ground longitudinal force based on the initial vehicle speed and the initial adjustment parameter can include: predicting the braking torque corresponding to the initial vehicle speed based on the initial adjustment parameter; determining the slip rate based on the braking torque corresponding to the initial vehicle speed and the initial vehicle speed; and determining the ground longitudinal force based on the slip rate and the wheel load information of the vehicle according to the tire magic formula.

[0090] In particular, the process of determining the slip rate based on the braking torque corresponding to the initial vehicle speed and the initial vehicle speed can include: updating the wheel speed of the vehicle according to the braking torque corresponding to the initial vehicle speed; and determining the slip rate according to the wheel speed and the initial vehicle speed.

[0091] In some embodiments, the process of predicting the pitch angular velocity information of the vehicle during braking comprises: determining the pitch angle of the vehicle based on the ground longitudinal force determined by the tire model and the suspension information of the vehicle by the target dynamics model; updating the suspension information of the vehicle according to the pitch angle; updating the pitch angle of the vehicle based on the updated suspension information and the new ground longitudinal force determined by the tire model, and continuing to perform the step of updating the suspension information of the vehicle according to the pitch angle to determine the pitch angular velocity information based on the obtained pitch angle.

[0092] The suspension information of the vehicle comprises vertical dynamic force of the suspension on the vehicle and vertical displacement of the suspension on the vehicle.

[0093] In some embodiments, the process of updating the suspension information of the vehicle according to the pitch angle can comprise: updating the vertical displacement according to the pitch angle and the dynamic parameters of the vehicle; and updating the vertical dynamic force based on the updated vertical displacement.

[0094] In some embodiments, the brake control method further comprises: generating an angular velocity error based on the pitch angular velocity, and generating a pitch angle error based on the pitch angle; and updating the vertical dynamic force of the suspension by a target regulation algorithm based on the pitch angle error and the angular velocity error.

[0095] The target regulation algorithm comprises a fuzzy proportional-integral-derivative control algorithm.

[0096] In some embodiments, the brake control method further comprises: updating the wheel load information of the vehicle based on the vertical dynamic force of the suspension, so that the tire model determines the ground longitudinal force based on the adjusted wheel load information.

[0097] In some embodiments, the target dynamics model further comprises a road roughness model.

[0098] Based on this, the process of determining the pitch angle of the vehicle based on the ground longitudinal force determined by the tire model and the suspension information of the vehicle by the target dynamics model can comprise: determining the pitch angle of the vehicle based on the ground longitudinal force determined by the tire model, the suspension information of the vehicle and a target noise by the target dynamics model, wherein the target noise is obtained by analyzing the roughness of the ground where the vehicle is located based on the road roughness model.

[0099] In order to facilitate understanding of the above-mentioned scheme, the brake analysis model shown in Figure 5 is used to explain and describe a specific embodiment.

[0100] Specifically, the present application provides a brake analysis model, which is a vehicle body-suspension-tire coupling system, mainly comprising two parts, namely a tire model and a vehicle body-suspension model (i.e. the target dynamics model mentioned in the embodiments of the present application).

[0101] Wherein, the tire model includes magic tire longitudinal force calculation module 201, vehicle speed calculation module 202, braking torque module 203, front wheel slip ratio calculation module 204 and rear wheel slip ratio calculation module 205. The vehicle speed output by the vehicle speed calculation module 202 and the braking torque output by the braking torque module 203 are jointly introduced into the front wheel slip ratio calculation module 204 and the rear wheel slip ratio calculation module 205, the wheel speed is updated based on the current braking torque, and the slip ratio is obtained by subtracting the vehicle speed, and the slip ratio is introduced into the magic tire longitudinal force calculation module 201 to solve the actual ground longitudinal force of the tire, and finally the ground longitudinal force is transmitted into the vehicle speed calculation module 202 to update the vehicle speed, forming a calculation closed loop.

[0102] Wherein, the body-suspension model includes active suspension displacement calculation module 206, active suspension output force calculation module 207, tire vertical acceleration calculation module 208, fuzzy PID controller 209, pitch angular velocity calculation module 210. When the pitch angular velocity calculation module 210 receives the ground longitudinal force provided by the magic tire longitudinal force calculation module 201, the whole vehicle produces pitch movement, the change of the pitch angle promotes the active suspension displacement calculation module 206 and the active suspension output force calculation module 207 to produce displacement and output force change in turn, and the results are input into the pitch angular velocity calculation module 210, and the system also forms a closed loop. At the same time, the active suspension output force calculation module 207 also causes the front and rear tire vertical load to change, which is then introduced back to the magic tire calculation process through the tire vertical acceleration calculation module 208. In order to suppress the pitch movement of the vehicle body, the fuzzy PID controller 209 is designed, which adjusts the suspension active force output in real time according to the pitch angle error and the pitch angular velocity error, and reduces the pitch impact of the whole vehicle. In addition to the above two parts, the system also has a ground unevenness disturbance module 211 to provide a ground disturbance signal.

[0103] It should be noted that the brake analysis model of the present application adds the vehicle body pitch center offset, the tire elastic damping model, the tire ground slip model, the ground unevenness disturbance model and the brake model on the basis of the existing dynamics model. When the vehicle brakes, the braking torque generates ground longitudinal force through the tire model, and the ground longitudinal force has an inertial pitch moment on the vehicle body. Secondly, the ground unevenness disturbance is also introduced to the vehicle body through the tire elastic damping model and the active suspension model in turn, and the pitch movement of the vehicle is generated by the joint action of the above factors. The previous analysis of the brake analysis model is too ideal, and cannot consider the effect of the vehicle body-suspension-tire coupling in the actual working condition, so that there is a certain deviation in the analysis and calculation of the whole vehicle pitch angle and angular velocity. The supplemented dynamics model can comprehensively analyze the influence of internal coupling, external disturbance and different driving conditions.

[0104] In some examples, as Figure 6As shown, the brake analysis model in the present application is a half-active suspension vehicle dynamics model, mainly including front and rear tires, front and rear active suspensions and a vehicle body and the like. The physical meanings of the variables of the dynamics model are shown in Table 1. Since the comfort braking regulation function generally intervenes at the end of braking, the vehicle speed is lower than 2 m / s, and the rolling resistance and the external resistance such as wind resistance can be ignored during analysis.

[0105] Table 1

[0106]

[0107] Specifically, the motion equation of the vertical displacement of the vehicle body can be:

[0108] The second derivative of the vertical displacement of the sprung mass * vehicle body = the vertical dynamic force of the front suspension + the vertical dynamic force of the rear suspension, which is specifically shown in the following formula (1-1), wherein is the vertical dynamic force of the front and rear suspensions.

[0109] (1-1).

[0110] When the ground longitudinal force intervenes, the process of calculating the vertical dynamic force of the front and rear active suspensions is respectively:

[0111] The vertical dynamic force of the front suspension = - the front suspension spring stiffness * (the vertical displacement of the front suspension - the vertical displacement of the front wheel) - the front suspension damping coefficient * (the first derivative of the vertical displacement of the front suspension - the first derivative of the vertical displacement of the front wheel) + the front suspension active force;

[0112] The vertical dynamic force of the rear suspension = - the rear suspension spring stiffness * (the vertical displacement of the rear suspension - the vertical displacement of the rear wheel) - the rear suspension damping coefficient * (the first derivative of the vertical displacement of the rear suspension - the first derivative of the vertical displacement of the rear wheel) + the rear suspension active force.

[0113] Specifically, as shown in the following formula (1-2):

[0114] (1-2).

[0115] It should be noted that the ground longitudinal force in the present application is taken as the positive direction in the direction of automobile braking, and the pitch moment is taken as the positive direction in the nodding direction of the vehicle.

[0116] In addition, since the pitch angle is small, combined with Figure 1 and formula (1-2), the process of calculating the vertical displacement of the front and rear active suspensions is respectively:

[0117] The vertical displacement of the front suspension = the vertical displacement of the vehicle body - the square root of [(the front wheelbase + the horizontal distance from the mass center to the pitch center) squared + the vertical distance from the mass center to the pitch center] * the pitch angle of the whole vehicle + the vertical displacement of the front wheel.

[0118] Rear suspension vertical displacement = vehicle body vertical displacement + square root of [ (rear wheelbase - horizontal distance from mass center to pitch center) squared + vertical distance from mass center to pitch center] * vehicle pitch angle + rear wheel vertical displacement.

[0119] Specifically, as shown in formula (1-3):

[0120] (1-3).

[0121] It should be noted that in the horizontal direction, the ground longitudinal force acting on the motion equation of the vehicle can be: half vehicle mass * vehicle speed first derivative = - (front wheel ground longitudinal force + rear wheel ground longitudinal force), which is specifically shown in formula (1-4):

[0122] (1-4).

[0123] Since the ground longitudinal force mainly comes from the frictional resistance generated when the front and rear wheels of the vehicle slip on the ground during braking, the torque motion equation when the wheels are braking can be expressed as:

[0124] Front wheel moment of inertia * front wheel speed first derivative = front wheel ground longitudinal force * wheel effective radius - front wheel braking torque;

[0125] Rear wheel moment of inertia * rear wheel speed first derivative = rear wheel ground longitudinal force * wheel effective radius - rear wheel braking torque.

[0126] Specifically, as shown in formula (1-5):

[0127] (1-5)

[0128] For the front and rear wheels, the vertical motion equation can be expressed as:

[0129] Second derivative of front wheel mass * front wheel vertical displacement = - front tire spring stiffness * (front wheel vertical displacement - front ground vertical displacement) - front suspension damping coefficient * (first derivative of front wheel vertical displacement - first derivative of front ground vertical displacement) - front suspension vertical dynamic force;

[0130] Second derivative of rear wheel mass * rear wheel vertical displacement = - rear tire spring stiffness * (rear wheel vertical displacement - rear ground vertical displacement) - rear suspension damping coefficient * (first derivative of rear wheel vertical displacement - first derivative of rear ground vertical displacement) - rear suspension vertical dynamic force.

[0131] Specifically, as shown in formula (1-6):

[0132] (1-6).

[0133] The vertical load between the front and rear tires and the ground in formula (1-6) is composed of a static vertical load and a dynamic vertical load, which can be specifically represented as:

[0134] Front wheel ground vertical force = rear wheelbase * half vehicle mass * g / (front wheelbase + rear wheelbase) - front suspension vertical dynamic force;

[0135] Rear wheel ground vertical force = front wheelbase * half vehicle mass * g / (front wheelbase + rear wheelbase) - rear suspension vertical dynamic force;

[0136] Front suspension vertical dynamic force = front tire spring stiffness * (front wheel vertical displacement - front ground vertical displacement) + front tire damping coefficient * (first derivative of front wheel vertical displacement - first derivative of front ground vertical displacement) + front suspension active force;

[0137] Rear suspension vertical dynamic force = rear tire spring stiffness * (rear wheel vertical displacement - rear ground vertical displacement) + rear tire damping coefficient * (first derivative of rear wheel vertical displacement - first derivative of rear ground vertical displacement) + rear suspension active force;

[0138] Specifically, as shown in formula (1-7):

[0139]

[0140] (1-7).

[0141] Further, according to the parallel axis theorem, the roll center moment of inertia can be represented as:

[0142] Roll center moment of inertia = vehicle body center of mass moment of inertia + sprung mass * square of horizontal distance from center of mass to roll center + square of vertical distance from center of mass to roll center.

[0143] Specifically, as shown in formula (1-8):

[0144] (1-8).

[0145] Based on the above formula, the overall vehicle body pitch motion equation can be determined, which can be represented as: roll center moment of inertia * second derivative of overall vehicle pitch angle = -front suspension vertical dynamic force * (front wheelbase + horizontal distance from center of mass to roll center) + rear suspension vertical dynamic force * (rear wheelbase - horizontal distance from center of mass to roll center) + front wheel ground longitudinal force * front wheel longitudinal force arm + rear wheel ground longitudinal force * rear wheel longitudinal force arm. Specifically, as shown in formula (1-9):

[0146] (1-9).

[0147] Wherein, the longitudinal force arm The solution mode of the front wheel longitudinal force arm is: the height of the mass center - the vertical distance from the mass center to the trim center + the vertical displacement of the vehicle body - the vertical displacement of the front suspension; the rear wheel longitudinal force arm = the height of the mass center - the vertical distance from the mass center to the trim center + the vertical displacement of the vehicle body - the vertical displacement of the rear suspension, which can be specifically shown according to the following formula (1-10):

[0148] (1-10).

[0149] Wherein, the vertical displacement of the ground is That is, the unevenness of the ground will affect the height of the longitudinal force acting on the wheel.

[0150] When braking, the front and rear wheel slip rate calculation mode is: front wheel slip rate = (real-time vehicle speed - front wheel speed * wheel travel effective radius) / real-time vehicle speed; rear wheel slip rate = (real-time vehicle speed - rear wheel speed * wheel travel effective radius) / real-time vehicle speed. It can be specifically shown according to the following formula (1-11):

[0151] (1-11).

[0152] For the tire model and the ground disturbance model, the application can use the classic magic tire formula to solve the ground longitudinal force. Wherein, the magic tire formula calculates the ground longitudinal force of the tire As shown in formula (1-12):

[0153] (1-12).

[0154] Wherein, is a stiffness factor, is a shape factor, is a peak factor, is a curvature factor.

[0155] Specifically, the calculation mode of the above stiffness factor, shape factor, peak factor and curvature factor is calculated according to formula (1-13):

[0156] (1-13).

[0157] Wherein, is the vertical load of the tire, that is, ,

[0158] It should be noted that the standard for describing the unevenness of the road surface of the vehicle vibration system input is the road surface power spectral density , which can be expressed as formula (1-14):

[0159] (1-14).

[0160] where, is the ground reference spatial frequency, generally taken as 0.1 m -1 , is the road roughness power spectral density at the reference spatial frequency, is the frequency exponent in different frequency ranges, generally a piecewise function.

[0161] Further, the time-domain excitation equation caused by the ground roughness can be simulated according to the following formula (1-15):

[0162] (1-15).

[0163] where, is the road roughness displacement input, i.e. , is the spatial frequency of the selected road, is the vehicle speed, is a white noise function.

[0164] Based on the above formula (1-15), the following formula (1-16) is obtained by rational function fitting, and the model parameters are obtained based on multi-level road simulation analysis .

[0165] (1-16)

[0166] where, the road roughness is mainly A, B, and C, in order to correspond to the road classification, generally select C road for simulation, the sampling time is taken as 10 ms , the noise power is set to 0.01 m 2 , then the ground roughness noise interference input is shown in Figure 7 .

[0167] Based on the above content, refer to Figure 8The braking control flow of a specific embodiment of the braking control method of the present application is as follows: initially, the vehicle travels at a constant speed, and when it is detected that the driver steps on the brake pedal, the comfortable braking function is triggered, and the initial state of the ground longitudinal force before the vehicle braking is taken as 0. The initial wheel speed is obtained by dividing the real-time vehicle speed estimated by the IMU state by the effective radius of the wheel travel. The wheel angular acceleration is calculated based on the brake torque measured by the wheel cylinder pressure sensor using formula (1-5). The wheel speed is updated by time integration. The slip ratio is obtained by formula (1-11) by subtracting the real-time vehicle speed signal. The calculated slip ratio is introduced into the magic tire longitudinal force calculation module 201, and the actual ground longitudinal force is solved by formula (1-12), and the result is substituted into formula (1-5) to iteratively calculate and update the wheel speed. The ground longitudinal force and wheel jump are introduced into the pitch angular velocity calculation module 210 as inputs. Since the ground longitudinal force generates a pitch moment on the center of gravity, but the suspension has damping characteristics, the vehicle body will produce a damped pitch motion. By coupling formula (1-4) and (1-9) with the suspension system, and integrating the instantaneous pitch angular acceleration, the pitch angular velocity, angle curve and deceleration curve generated by braking can be predicted. The difference between the predicted pitch angular velocity and pitch angle and zero is taken as a two-dimensional error variable, which is input into the fuzzy PID controller 209 for feedback calculation. The required suspension active force request value for suppressing suspension pitch motion is calculated by the fuzzy control rule table, and the peak value of the pitch angular velocity curve is reduced to reduce the impact. According to the predicted deceleration curve and pitch angular velocity curve, the peak and valley values of the pitch angular velocity curve are taken as the fitness function, and the braking distance, parking time and minimum brake torque are taken as the constraint conditions. The shape adjustment parameters of the brake torque curve are optimized by the GA genetic algorithm, so as to calculate the optimal brake torque curve in the middle of the brake Figure 3 At the end of the braking stage, the wheel brake torque is actively reduced until the vehicle is completely stopped, and the comfortable braking function is exited. For different road adhesion coefficients, the maximum brake torque and braking danger of the vehicle under the non-locking condition are different, so the range of the internal constraint condition is adjusted according to the size of the road adhesion coefficient, so as to effectively reduce the maximum amplitude of the pitch angular velocity at the braking parking time on the basis of ensuring braking safety, improve the comfort of passengers, and prevent car sickness.

[0168] In this way, under different braking intensities and road adhesion coefficients, the system can automatically adjust the comfortable braking torque curve to achieve optimal compensation of the vehicle body pitch angular velocity and improve the driving comfort. In addition, the influence on the braking distance is also analyzed.

[0169] Specifically, a fuzzy PID controller is designed based on the active suspension to adjust the pitch motion, taking the pitch angle error e and the angular velocity error ec as input signals, selecting the fuzzy domain according to the pitch angle and the angular velocity error of the vehicle without control during braking, and integrating the input and output signals into the domain through normalization operation. Seven fuzzy language variable subsets are selected as {NB, NM, NS, ZO, PS, PM, PB}, the input variables are fuzzified by using the Gaussian membership function, the controller output value is the adjustment variable of the PID control unit, which is the proportional variable Δkp, the integral variable Δki and the differential variable Δkd, respectively. A fuzzy rule table is formulated to determine the relationship between the fuzzy input signals and the output signals, and then the PID adjustment variable value corresponding to the current input signal is obtained by means of defuzzification, the adjustment variable is summed with the initial PID parameters to update the control unit, and adaptive PID control of the system is realized.

[0170] Before simulation Figure 6 The parameters of the active suspension vehicle dynamics model, such as mass, wheelbase, spring stiffness and damping, are set, as shown in Figure 9 An initial braking torque embodiment of the present application is shown, the brake pedal is pressed to brake at 3s, the braking torque rises to the maximum at 4s, and the front and rear wheel braking torque distribution coefficient is 0.5. Considering the actual suspension performance limit, the maximum adjustment force range that the active suspension can output is set, and the active suspension is simulated without control, PID controller and fuzzy PID controller, respectively, and the pitch angular velocity simulation results are shown in Figure 10 It can be seen that the adaptive fuzzy PID algorithm can reduce the pitch angular velocity peak value and valley value at the end of braking, and the effect is better than that of the PID controller, and the braking distance is not affected. This method can improve the vehicle ride comfort and does not affect the braking efficiency, but the adjustment range of the active suspension is affected by many factors such as cost and structure, and the ability to improve the braking pitch impact is limited.

[0171] Further, a combined control method is designed for vehicle braking comfort by combining the above fuzzy PID suspension controller and the comfortable braking torque curve. The body-suspension-tire coupling model is simulated without pitch motion adjustment, only using the active suspension fuzzy PID controller, only using the comfortable braking torque curve, and using the active suspension fuzzy PID controller and the comfortable braking torque curve at the same time, and the pitch angular velocity comparison is shown in Figure 11 It can be observed that under the combined adjustment strategy, the peak value of the vehicle pitch angular velocity during braking is reduced by 74%, and the valley value is reduced by 63%.

[0172] Thus, a fuzzy PID controller was designed, using the pitch velocity error and pitch angle error during vehicle braking as inputs. The controller then controlled the suspension damping current in real time to adjust the vehicle's pitch velocity using feedback. Simulated pitch velocity curves before and after the fuzzy PID controller were compared under different braking conditions. The results show that compared to conventional PID controllers, the fuzzy PID controller reduced both the pitch velocity amplitude and pitch angle overshoot during braking. Compared to other algorithms, this algorithm offers low resource consumption and high robustness, making it suitable for practical vehicle applications.

[0173] Based on this, this application proposes a vehicle comfort braking strategy for different road adhesion coefficients, such as Figure 12 As shown in the figure, first, sensors are used to collect vehicle driving information. The sensor system mainly includes a center of mass accelerometer, a center of mass gyroscope, a wheel speed sensor, a brake pedal depth sensor, and a lidar ranging unit. The collected data is collected in a central domain processor for filtering and state estimation. The road adhesion coefficient of each wheel, slip rate, vehicle speed, brake pedal braking force, distance to the obstacle in front and other signals are calculated. Based on this signal, the working logic of the vehicle's comfort braking function is determined.

[0174] In some embodiments, when the vehicle has a braking demand, the process of obtaining the braking torque curve may include: obtaining the braking torque curve when the vehicle has a braking demand and the environment in which the vehicle is located meets a safety environment condition.

[0175] Among them, the safety environment conditions are determined based on the road adhesion coefficient of the vehicle's environment.

[0176] In other embodiments, the above-mentioned braking control method may further include: when the vehicle has a braking demand and the environment in which the vehicle is located does not meet the safety environment conditions, controlling the braking movement of the vehicle based on the initial braking torque when the vehicle has a braking demand.

[0177] Specifically, the vehicle's comfort braking combination control strategy actively reduces wheel braking torque at the end of braking, slightly increasing the final stopping distance and weakening the vehicle's braking performance. Therefore, this comfort braking function must be used while ensuring driving safety. It is only suitable for routine braking conditions in daily traffic and should not be triggered under extreme braking conditions. For example, during braking, the function will automatically deactivate if the ABS function requires anti-lock braking or the AEB function requires emergency braking for collision avoidance.

[0178] In addition, due to the different adhesion coefficients of each wheel during vehicle driving, the vehicle will also pass through opposing roads or connecting roads. In order to maintain the vehicle driving stability, the comfort braking function will be interrupted when the stability function of the opposing roads or connecting roads is turned on, and the comfort braking function will be restarted after the road surface is restored.

[0179] The comfortable braking function on the uniform road surface should change the braking combination adjustment strategy according to the difference of the road surface adhesion coefficient, and the road surface with different adhesion coefficients has a significant influence on the effective adjustment range of the braking torque. Considering that the braking distance of the low adhesion ground such as ice and snow surface is generally higher than that of the high adhesion ground, the braking safety risk is high and the accident rate is high, and the braking distance should not be increased. Therefore, the algorithm provided in the application does not adjust the braking torque curve on the ice surface with a road surface adhesion coefficient less than 0.3, and on the wet road surface and the dust road surface with a road surface adhesion coefficient greater than 0.3 and less than 0.6, the braking distance calculated according to the initial braking torque and the road surface adhesion coefficient is used as a boundary constraint condition for genetic optimization of the braking torque curve, and the braking torque adjustment range needs to be reduced. On the dry concrete road surface and the asphalt road surface with a road surface adhesion coefficient greater than 0.6, the braking torque adjustment ability is completely opened. The combined adjustment strategy of the vehicle braking pitch comfort provided in the application can greatly optimize the driving comfort under the condition of ensuring the driving safety.

[0180] In this way, the comfortable braking function is designed by combining the advantages of the active suspension and the braking torque curve, and the pitch impact of the vehicle is suppressed in the vehicle braking working condition. The comfortable braking function is generally used in the daily driving braking working condition, and the interaction of a series of functions such as ABS, AEB and ADAS is considered. The comfortable braking torque curve can increase the braking distance to a certain extent, and the driving safety is considered comprehensively. An intelligent chassis comfortable braking control strategy that can be dynamically adjusted according to the difference of the road surface adhesion coefficient is proposed, and the driving comfort can be effectively improved.

[0181] The embodiment of the application further provides a controller, as shown in Figure 13 The embodiment of the application further provides a controller, as shown in

[0182] The controller can include a processor 301 with one or more processing cores, a memory 302 with one or more storage media, a power supply 303 and an input unit 304 and the like. Those skilled in the art can understand that Figure 13 The controller structure shown in the figure does not constitute a limitation on the controller, and can include more or fewer components than the figure, or combine certain components, or different component arrangements. Among them:

[0183] The processor 301 is the control center of the controller, and connects various parts of the controller through various interfaces and lines, and performs various functions of the controller and processes data by running or executing computer programs and / or modules stored in the memory 302 and calling data stored in the memory 302. Optionally, the processor 301 can include one or more processing cores; preferably, the processor 301 can integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface and application program, etc., and the modem processor mainly processes wireless communication. It can be understood that the above-mentioned modem processor can also not be integrated into the processor 301.

[0184] The memory 302 can be used to store computer programs and modules, and the processor 301 executes various functions and brake controls by running the computer programs and modules stored in the memory 302. The memory 302 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, computer programs required by at least one function (such as an audible and light prompt function, a brake control function, etc.), etc.; and the data storage area can store data created according to the use of the controller, etc. In addition, the memory 302 can include a high-speed random access memory, and can also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other volatile solid-state memory device. Accordingly, the memory 302 can also include a memory controller to provide the processor 301 with access to the memory 302.

[0185] The controller also includes a power supply 303 for powering various components, and preferably the power supply 303 can be logically connected to the processor 301 through a power management system, so as to realize functions such as management of charging, discharging and power consumption management through the power management system. The power supply 303 can also include one or more than one direct current or alternating current power supply, a recharging system, a power failure detection circuit, a power converter or inverter, a power state indicator, etc. Any component.

[0186] The controller can also include an input unit 304, which can be used to receive input digital or character information, and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function controls.

[0187] Although not shown, the controller can also include a display unit, etc., which will not be described here. In particular, in the present embodiment, the processor 301 in the controller will load the executable file corresponding to the process of one or more computer programs into the memory 302 according to the following instructions, and the processor 301 will run the computer programs stored in the memory 302, so as to realize various functions, such as:

[0188] In a case where the vehicle has a braking demand, a braking torque curve is acquired, wherein the braking torque curve comprises at least two braking torques with a braking sequence and switching control parameters of adjacent braking torques, and the braking torque in the later braking sequence is smaller than the braking torque in the earlier braking sequence;

[0189] The braking motion of the vehicle is controlled based on the braking torque in the braking torque curve and the switching control parameters.

[0190] Therefore, the controller provided in the embodiments of the present application acquires a braking torque curve in a case where the vehicle has a braking demand, wherein the braking torque curve comprises at least two braking torques with a braking sequence and switching control parameters of adjacent braking torques, and the braking torque in the later braking sequence is smaller than the braking torque in the earlier braking sequence; and the braking motion of the vehicle is controlled based on the braking torque in the braking torque curve and the switching control parameters. In this way, the braking motion of the vehicle is controlled by using a braking torque curve comprising multiple braking torques with different sizes and different braking sequences, so as to reduce the braking torque to reduce the pitching impact of the vehicle when stopping and improve the user experience.

[0191] The specific implementation manners of the above operations and the corresponding advantages can be referred to the detailed description of the braking control method, and will not be described herein.

[0192] Those skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by a computer program, or by a computer program controlling related hardware, which can be stored in a storage medium and loaded and executed by a processor.

[0193] Therefore, the present application provides a storage medium, which stores a computer program capable of being loaded by a processor to execute the steps in any one of the braking control methods provided in the embodiments of the present application. For example, the computer program can execute the following steps:

[0194] In a case where the vehicle has a braking demand, a braking torque curve is acquired, wherein the braking torque curve comprises at least two braking torques with a braking sequence and switching control parameters of adjacent braking torques, and the braking torque in the later braking sequence is smaller than the braking torque in the earlier braking sequence;

[0195] The braking motion of the vehicle is controlled based on the braking torque in the braking torque curve and the switching control parameters.

[0196] Therefore, the storage medium provided in the embodiments of the present application can obtain a braking torque curve in the case that the vehicle has a braking demand, wherein the braking torque curve comprises at least two braking torques with braking sequences and switching control parameters of adjacent braking torques, and the braking torque with a later braking sequence is smaller than the braking torque with an earlier braking sequence; and the braking movement of the vehicle is controlled based on the braking torque and the switching control parameter in the braking torque curve. Based on this, the braking movement of the vehicle is controlled by using the braking torque curve comprising multiple braking torques with different sizes and different braking sequences, so as to reduce the braking torque to reduce the pitching impact of the vehicle when parking, and improve the user experience.

[0197] The specific implementation and corresponding beneficial effects of each operation above can be referred to the embodiments above, and will not be described here.

[0198] The storage medium can include a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0199] The computer program stored in the storage medium can execute the steps of any one of the braking control methods provided in the embodiments of the present application, so that the beneficial effects of any one of the braking control methods provided in the embodiments of the present application can be achieved. Details can be referred to the embodiments above, and will not be described here.

[0200] According to an aspect of the present application, a computer program product or a computer program is provided, which comprises computer instructions stored in a storage medium. The processor of a computer device reads the computer instructions from the storage medium, and the processor executes the computer instructions to make the computer device execute the braking control method described above.

[0201] The embodiments of the present application also provide a vehicle comprising the controller described above or the computer program product described above.

[0202] For example, the vehicle comprises the controller described above, which obtains a braking torque curve in the case that the vehicle has a braking demand, wherein the braking torque curve comprises at least two braking torques with braking sequences and switching control parameters of adjacent braking torques, and the braking torque with a later braking sequence is smaller than the braking torque with an earlier braking sequence; and the braking movement of the vehicle is controlled based on the braking torque and the switching control parameter in the braking torque curve. Based on this, the braking movement of the vehicle is controlled by using the braking torque curve comprising multiple braking torques with different sizes and different braking sequences, so as to reduce the braking torque to reduce the pitching impact of the vehicle when parking, and improve the user experience.

[0203] The specific structure of the vehicle is not limited in the present application. The specific implementation and the corresponding beneficial effects of the above operations of the control device are also applicable to the vehicle, and specific reference can be made to the detailed description of the vehicle control method above, which is not repeated here.

[0204] The above describes in detail the brake control method, controller, storage medium, computer program product and vehicle provided by the embodiments of the present application. The principles and implementation manners of the present application are described by applying specific examples. The above embodiment description is only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, the specific implementation manner and application range will be changed according to the idea of the present application. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A braking control method, characterized in that: The method comprises: When the vehicle has a braking demand, predicting a deceleration curve and a pitch angular velocity curve of the vehicle during the braking process; determining an optimization target required for generating a braking torque curve based on the pitch angular velocity curve, and determining a constraint condition required for generating the braking torque curve based on the deceleration curve; determining a braking torque curve according to the optimization objective and the constraint condition, wherein the braking torque curve includes at least two braking torques having a braking sequence and a switching control parameter of adjacent braking torques, and a braking torque in a later braking sequence is smaller than a braking torque in an earlier braking sequence; controlling a braking motion of the vehicle based on the braking torque in the braking torque curve and the switching control parameter; The switching control parameter includes a switching start condition, the braking torque curve includes a first braking torque and a second braking torque, and a braking order of the first braking torque is located before a braking order of the second braking torque; and controlling the braking movement of the vehicle based on the braking torque in the braking torque curve and the switching control parameter includes: controlling a braking movement of the vehicle based on the first braking torque; When the switching start condition is met, the first braking torque is switched to the second braking torque based on the switching control parameter to continue controlling the braking movement of the vehicle, wherein the switching start condition includes the vehicle speed being reduced to a preset speed, and / or the braking moment of the braking movement of the vehicle controlled based on the braking torque reaches the torque reduction start moment.

2. The braking control method according to claim 1, characterized in that: The switching control parameter further includes a torque decreasing speed, and the controlling the switching of the first braking torque to the second braking torque based on the switching control parameter to continue controlling the braking movement of the vehicle includes: controlling, according to the torque reduction speed, to reduce the braking torque of the vehicle from the first braking torque to the second braking torque; Based on the second braking torque, the braking movement of the vehicle continues to be controlled.

3. The braking control method according to claim 2, characterized in that: The switching control parameter also includes a torque reduction end time, which is used to indicate an end time for reducing the braking torque of the vehicle. At the torque reduction end time, the braking torque of the vehicle is the second braking torque.

4. The braking control method according to claim 1, wherein: The optimization target is determined based on peak values ​​and valley values ​​of the pitch rate curve.

5. The braking control method according to claim 1, characterized in that: Determining the constraint conditions required for generating the braking torque curve based on the deceleration curve includes: The constraint condition is determined according to the deceleration curve and environmental parameters of the environment in which the vehicle is located.

6. The braking control method according to claim 5, characterized in that: The environmental parameters include a road adhesion coefficient, and the constraint conditions include a braking torque range, a braking distance range, and a stopping time determined based on the road adhesion coefficient and the deceleration curve.

7. The brake control method according to claim 1, characterized in that: The predicting of a deceleration curve and a pitch angular velocity curve of the vehicle during braking includes: setting initial adjustment parameters for generating a braking torque curve according to an initial braking torque when the vehicle has a braking demand, the initial adjustment parameters including the initial braking torque, at least one braking torque subsequent to the initial braking torque in a braking sequence, and a switching control parameter between adjacent braking torques; Based on the initial adjustment parameters, a deceleration curve and a pitch angular velocity curve of the vehicle during braking are predicted.

8. The brake control method according to claim 7, characterized in that: The initial braking torque is determined based on a pedal depth of the vehicle and a corresponding relationship between a preset pedal depth and a preset braking torque.

9. The braking control method according to claim 7, characterized in that: Determining the braking torque curve according to the optimization objective and the constraint conditions includes: constructing a plurality of candidate braking torque curves based on the initial adjustment parameters, the optimization target, and the constraint conditions, wherein the adjustment parameters of different candidate braking torque curves are different; Parameter optimization processing is performed on the plurality of candidate braking torque curves, and the candidate braking torque curve obtained by the optimization is used as the braking torque curve.

10. The brake control method according to claim 7, wherein: The vehicle is equipped with a braking analysis model, and the deceleration curve and pitch angular velocity curve of the vehicle during braking are predicted based on the initial adjustment parameters, including: Predicting, by the braking analysis model, vehicle speed information and pitch angular velocity information of the vehicle during braking based on the initial adjustment parameters and the initial vehicle speed of the vehicle when braking is required; constructing the deceleration curve according to a plurality of vehicle speeds in a sequential order included in the vehicle speed information; The pitch angular velocity curve is constructed according to a plurality of pitch angular velocities in a sequential order included in the pitch angular velocity information.

11. The brake control method according to claim 10, characterized in that: The braking analysis model includes a tire model, and the process of predicting the vehicle speed information during braking includes: Determining a ground longitudinal force based on the tire model and the initial vehicle speed and the initial adjustment parameters; updating the vehicle speed based on the ground longitudinal force and a preset correspondence between the tire ground longitudinal force and a preset vehicle speed; Based on the updated vehicle speed and the initial adjustment parameters, a new ground longitudinal force is determined, and the step of updating the vehicle speed based on the ground longitudinal force and the corresponding relationship between the preset tire ground longitudinal force and the preset vehicle speed is continued to obtain the vehicle speed information.

12. The brake control method according to claim 11, characterized in that: Determining the ground longitudinal force based on the initial vehicle speed and the initial adjustment parameters using the tire model includes: predicting a braking torque corresponding to the initial vehicle speed based on the initial adjustment parameters; determining a slip ratio based on a braking torque corresponding to the initial vehicle speed and the initial vehicle speed; The ground longitudinal force is determined based on the slip ratio and wheel load information of the vehicle according to a tire magic formula.

13. The brake control method according to claim 12, wherein: The determining of the slip ratio based on the braking torque corresponding to the initial vehicle speed and the initial vehicle speed includes: updating the wheel speed of the vehicle according to the braking torque corresponding to the initial vehicle speed; A slip ratio is determined based on the wheel speed and the initial vehicle speed.

14. The brake control method according to claim 11, characterized in that: The braking analysis model includes a target dynamics model determined based on at least a dynamics model of the vehicle and a suspension model of the vehicle.

15. The brake control method according to claim 14, characterized in that: The process of predicting the pitch angular velocity information of the vehicle during braking includes: determining, by the target dynamics model, a pitch angle of the vehicle based on the ground longitudinal force determined by the tire model and suspension information of the vehicle; updating suspension information of the vehicle according to the pitch angle; Based on the updated suspension information and the new ground longitudinal force determined by the tire model, the pitch angle of the vehicle is updated, and the step of updating the suspension information of the vehicle according to the pitch angle is continued to determine the pitch angular velocity information based on the obtained pitch angle.

16. The brake control method according to claim 15, characterized in that: The suspension information of the vehicle includes the vertical dynamic force of the suspension on the vehicle and the vertical displacement of the suspension on the vehicle.

17. The brake control method according to claim 16, characterized in that: The updating of the suspension information of the vehicle according to the pitch angle includes: updating the vertical displacement according to the pitch angle and the dynamic parameters of the vehicle; The vertical dynamic force is updated based on the updated vertical displacement.

18. The brake control method according to claim 16, wherein: The method further comprises: generating an angular velocity error based on the pitch angular velocity, and generating a pitch angle error based on the pitch angle; The vertical dynamic force of the suspension is updated based on the pitch angle error and the angular velocity error through a target adjustment algorithm.

19. The brake control method according to claim 18, characterized in that: The target adjustment algorithm includes a fuzzy proportional-integral-derivative control algorithm.

20. The brake control method according to claim 16, wherein: The method further comprises: Based on the vertical dynamic force of the suspension, wheel load information of the vehicle is updated so that the tire model determines the ground longitudinal force based on the adjusted wheel load information.

21. The brake control method according to claim 15, characterized in that: The target dynamics model further includes a ground roughness model. Determining the pitch angle of the vehicle by using the target dynamics model based on the ground longitudinal force determined by the tire model and suspension information of the vehicle includes: The pitch angle of the vehicle is determined by the target dynamics model based on the ground longitudinal force determined by the tire model, the suspension information of the vehicle, and target noise, wherein the target noise is obtained by analyzing the unevenness of the ground on which the vehicle is located based on the ground unevenness model.

22. The brake control method according to any one of claims 1 to 21, characterized in that: The step of obtaining a braking torque curve when the vehicle has a braking demand includes: When the vehicle has a braking demand and the environment in which the vehicle is located meets a safety environment condition, a braking torque curve is obtained.

23. The brake control method according to claim 22, characterized in that: The safety environment condition is determined based on a road adhesion coefficient of an environment in which the vehicle is located.

24. The brake control method according to claim 22, wherein: The method further comprises: When the vehicle has a braking demand and the environment in which the vehicle is located does not meet a safety environment condition, the braking movement of the vehicle is controlled based on an initial braking torque when the vehicle has a braking demand.

25. A controller, characterized in that: The invention comprises one or more processors and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor is caused to perform the steps of the brake control method according to any one of claims 1 to 24.

26. A storage medium, characterized in that The invention comprises a computer program, which is used to make the controller perform the steps of the brake control method according to any one of claims 1 to 24 when the computer program is run on the controller.

27. A computer program product, characterized in that The method comprises a computer program or instructions, which implements the steps of the braking control method according to any one of claims 1 to 24 when the computer program or instructions are executed by a processor.

28. A vehicle, characterized in that: The vehicle includes the controller of claim 25.

Images