A brake-by-wire vehicle slip ratio control method and system

Abstract

The application relates to a kind of line control brake vehicle slip rate control method and system, comprising the following steps: based on the vehicle speed of the vehicle to be controlled, wheel rotation speed and current road adhesion coefficient collected, judge whether it needs to activate slip rate control: if it needs to activate, based on the control-oriented slip rate control system model and preset performance control strategy constructed in advance, the road adhesion coefficient is estimated, and the road adhesion coefficient estimated is used by the motor servo line control brake system of the vehicle itself to control the vehicle to be controlled;Otherwise, the current road adhesion coefficient is used by the motor servo line control brake system of the vehicle itself to control the vehicle to be controlled.Using the method of the application, the dynamic and steady-state response error of the key parameter slip rate in the vehicle braking slip process can be converged to the pre-set error boundary within a limited time.Therefore, the application can be widely applied to the slip rate control of vehicle.

Description

Technical Field

[0001] This invention proposes a method and system for controlling the slip ratio of brake-by-wire vehicles, relating to the field of vehicle brake-by-wire. Background Technology

[0002] Autonomous driving is a disruptive technology that will lead the future and have a profound impact on social development. It is a strategic high ground for the upgrading of the global automotive industry and the transformation of transportation development models. Among them, slip ratio control is a key factor in ensuring vehicle stability during braking and a prerequisite for accurately handling emergency collision avoidance. It is of great significance for realizing advanced levels of autonomous driving, expanding the safety boundaries of autonomous driving, and accelerating the implementation of the technology.

[0003] As a core underlying technology for autonomous vehicles, the development of brake-by-wire technology has injected more possibilities into slip ratio control. Different brake-by-wire systems have different impacts on achieving slip ratio control. The electric servo hydraulic brake-by-wire system uses a servo motor to drive the master cylinder to achieve active braking. Depending on whether the servo motor and the driver directly drive the same master cylinder, the electric servo hydraulic brake-by-wire system can be further divided into a single-master-cylinder scheme represented by Bosch iBooster and a dual-master-cylinder scheme represented by Continental MKC1. Regardless of whether it's a single-master-cylinder or dual-master-cylinder scheme, the principle behind this type of hydraulic brake-by-wire system is that the electric servo motor drives the brake fluid in the master cylinder to achieve active braking. Its system control is simple and its response speed is fast, thus it has a significant advantage in slip ratio control and the potential to precisely control the vehicle's slip ratio.

[0004] However, autonomous driving demands high levels of safety. Currently, insufficient vehicle controllability and imprecise control in emergency collision avoidance scenarios severely limit the implementation and widespread adoption of autonomous driving technology. Autonomous driving is primarily applied to routine driving conditions and cannot handle sudden situations such as high-speed collision avoidance, which is one of the major causes of autonomous driving accidents. Summary of the Invention

[0005] To address the aforementioned problems, the purpose of this invention is to provide a slip ratio control method and system for brake-by-wire vehicles. Taking advantage of the fast response speed and high response accuracy of motor servo hydraulic brake-by-wire systems, a precision slip ratio control method based on preset performance is designed.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for controlling the slip ratio of a brake-by-wire vehicle, comprising the following steps:

[0008] Based on the collected data on the vehicle speed, wheel speed, and current road surface adhesion coefficient of the controlled vehicle, it is determined whether slip ratio control needs to be activated:

[0009] If activation is required, the road adhesion coefficient is estimated based on a pre-built control-oriented slip ratio control system model and a preset performance control strategy. The vehicle's own motor servo brake-by-wire system then uses the estimated road adhesion coefficient to control the vehicle.

[0010] Otherwise, the vehicle's own motor servo drive system controls the vehicle using the current road surface adhesion coefficient.

[0011] Furthermore, the determination of whether slip ratio control needs to be activated includes:

[0012] The current vehicle slip ratio is obtained based on the collected vehicle speed and wheel speed of the controlled vehicle.

[0013] The current vehicle slip ratio is compared with the preset slip ratio control trigger threshold. If the slip ratio control trigger threshold is greater than the current vehicle slip ratio, the slip ratio control mode is triggered.

[0014] Furthermore, the estimation of the road surface adhesion coefficient based on the pre-constructed control-oriented slip ratio control system model and the preset performance control strategy includes:

[0015] Collect the ground support force on the wheels of the controlled vehicle and the current road surface adhesion coefficient to generate the optimal slip ratio target value;

[0016] Based on the target value of the optimal slip ratio and the current slip ratio of the controlled vehicle, the road adhesion coefficient is estimated using a preset performance control strategy.

[0017] Furthermore, the step of collecting the ground support force on the wheels of the controlled vehicle and the current road surface adhesion coefficient to generate the optimal slip ratio target value includes:

[0018] The forces acting on the wheels of the controlled vehicle during operation are analyzed, and a tire dynamics model is established.

[0019] Determine the slip ratio dynamic model of the controlled vehicle;

[0020] Based on the established tire dynamics model and slip ratio dynamics model, a slip ratio control system model oriented towards control is obtained;

[0021] Based on the control-oriented slip ratio control system model, the ground support force on the wheels of the controlled vehicle, and the current road surface adhesion coefficient, the optimal slip ratio target value is calculated.

[0022] Furthermore, the estimation of the road surface adhesion coefficient based on the optimal slip ratio target value and the current slip ratio of the controlled vehicle, using a preset performance control strategy, includes:

[0023] Based on the state response requirements of the slip ratio control system and the motor servo brake-by-wire system, preset performance parameters are selected and preset performance functions are designed.

[0024] Based on the predetermined performance function, a first error transformation is performed to obtain the intermediate control input x. 2d This allows for the constraint of system errors through a preset performance function;

[0025] Based on the predetermined performance function, a second error variable is calculated to obtain the road surface adhesion coefficient.

[0026] Furthermore, the preset performance function is:

[0027]

[0028] Where φ1(t) is a smooth function, and it satisfies the following conditions:

[0029] a. φ1(t) is monotonically decreasing and φ1(t) > 0;

[0030] b. Under the initial conditions, φ1(0)>|e1(0)|;

[0031] c. The limit of the function as time approaches infinity. Existence, and

[0032] d、δ 10 ≥δ 1∞ >0,

[0033] Where, δ 10 δ 1∞ a1 and a1 represent the upper and lower boundaries of the pre-set reasonable shift rate control error and the convergence speed, respectively, all of which are unitless.

[0034] Furthermore, the input to the motor servo brake-by-wire system is:

[0035]

[0036] Where u represents the displacement control input of the motor servo linear braking system, and the unit is m.

[0037] In a second aspect, the present invention provides a slip ratio control system for brake-by-wire vehicles, comprising:

[0038] The activation judgment module is used to determine whether slip ratio control needs to be activated based on the collected vehicle speed, wheel speed, and current road surface adhesion coefficient of the controlled vehicle. If activation is required, a signal is sent to the road surface adhesion coefficient estimation module; otherwise, a signal is sent to the vehicle's own motor servo brake-by-wire system.

[0039] The slip ratio control module is used to estimate the road adhesion coefficient based on a pre-built control-oriented slip ratio control system model and a preset performance control strategy. The estimated road adhesion coefficient is then used by the vehicle's own motor servo brake-by-wire system to control the controlled vehicle.

[0040] The conventional control module is used by the vehicle's own motor servo drive-by-wire braking system to control the vehicle using the current road surface adhesion coefficient.

[0041] Thirdly, the present invention provides a processing device, the processing device including at least a processor and a memory, the memory storing a computer program, and the processor executing the steps of the skid ratio control method for the brake-by-wire vehicle when running the computer program.

[0042] Fourthly, the present invention provides a computer storage medium having computer-readable instructions stored thereon, the computer-readable instructions being executable by a processor to implement the steps of the brake-by-wire vehicle slip ratio control method.

[0043] The present invention has the following advantages due to the adoption of the above technical solutions:

[0044] This invention, through a pre-set performance method, allows for the pre-setting of the transient and steady-state performance of the slip ratio response of brake-by-wire vehicles, thereby meeting the requirements of technological development. Compared to traditional experience-based proportional-derivative-integral methods, this invention possesses model-based precision. Compared to common methods such as slip diaphragm control, this invention features pre-setting of the dynamic and steady-state responses of the slip ratio. This invention can achieve pre-set transient and steady-state response requirements for vehicle slip ratio control; rigorous mathematical proof demonstrates that the slip ratio under this method will necessarily achieve the pre-set performance. The method proposed in this invention can improve the slip ratio control accuracy of vehicles based on motor servo brake-by-wire systems, ensuring more precise braking force output. This invention plays a fundamental role in improving the emergency collision avoidance capabilities of future high-level brake-by-wire automated vehicles. Attached Figure Description

[0045] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0046] Figure 1 This is a schematic diagram of the physical system model provided in an embodiment of the present invention;

[0047] Figure 2This is a graph showing the relationship between the preset performance function and the error of the controlled system provided in this embodiment of the invention.

[0048] Figure 3 This is a schematic flowchart of the slip ratio control method for brake-by-wire vehicles provided in an embodiment of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0050] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0051] In some embodiments of the present invention, a slip ratio control method for a brake-by-wire vehicle is provided. By presetting the transient and steady-state performance of the slip ratio response of the brake-by-wire vehicle through a preset performance method, the transient and steady-state response requirements of the vehicle's slip ratio control can be achieved, thereby improving the slip ratio control accuracy of the vehicle based on the motor servo brake-by-wire system and ensuring more precise braking force output.

[0052] Correspondingly, in some embodiments of the present invention, a slip ratio control system, device, and medium for brake-by-wire vehicles are also provided.

[0053] Example 1

[0054] like Figure 1 As shown, this embodiment provides a slip ratio control method for a brake-by-wire vehicle, including the following steps:

[0055] 1) Based on the collected vehicle speed and wheel speed of the controlled vehicle, obtain the current vehicle slip ratio, determine whether slip ratio control needs to be activated, if activation is required, proceed to step 2), otherwise proceed to step 3).

[0056] 2) Based on the pre-built control-oriented slip ratio control system model and the preset performance control strategy, the road adhesion coefficient is estimated, and the vehicle's own motor servo brake-by-wire system uses the estimated road adhesion coefficient to control the controlled vehicle.

[0057] 3) Based on the pressure-position dual closed-loop control strategy, the vehicle's own motor servo drive system uses the measured current road surface adhesion coefficient to control the controlled vehicle.

[0058] Preferably, step 1) above includes the following steps:

[0059] 1.1) The current vehicle slip ratio λ is obtained based on the collected vehicle speed and wheel speed of the controlled vehicle.

[0060] In the field of vehicle control, the slip ratio of a vehicle is defined as follows:

[0061]

[0062] Among them, v x Represents the longitudinal velocity of the vehicle, measured in m / s; ω r This represents the rotational speed of the wheel.

[0063] 1.2) Compare the current vehicle slip ratio with the preset slip ratio control trigger threshold λ s The comparison is performed, and if the slip ratio control trigger threshold is greater than the current vehicle slip ratio, then the slip ratio control mode is triggered.

[0064] Among them, the slip ratio control trigger threshold λ s The setting varies depending on the road surface conditions, and is generally selected within the range of 0.15-0.2.

[0065] Preferably, in step 2) above, estimating the road surface adhesion coefficient includes the following steps:

[0066] 2.1) Collect the ground support force on the wheels of the controlled vehicle and the current road surface adhesion coefficient to generate the optimal slip ratio target value λ. d .

[0067] The ground support force on the wheel is represented by F. z The coefficient of adhesion of the current road surface is expressed in μ (N). est It indicates that there are no units; and the measurement of the two parameters is a fundamental function in the field of vehicle control, and the measurement method will not be discussed in detail in this invention.

[0068] 2.2) Based on the target value λ of the optimal slip ratio d Given the current slip ratio λ of the controlled vehicle, the road surface adhesion coefficient is estimated using a preset performance control strategy.

[0069] Preferably, in step 2.1) above, the target value λ for the optimal slip ratio is generated. d The method includes the following steps:

[0070] 2.1.1) Analyze the forces acting on the wheels of the controlled vehicle during operation and establish a tire dynamics model.

[0071] like Figure 1 The diagram shows the forces acting on the wheels of a vehicle during operation. Here, Road represents the road surface, Wheel represents the wheel, and F... z F represents the ground support force exerted on the wheel. w ω represents the longitudinal resistance of the wheel to the ground. r v represents the rotational speed of the wheel. x The speed of the vehicle is represented by r, and the wheel radius is represented by r.

[0072] Therefore, the tire dynamics model of the vehicle braking process can be represented as follows:

[0073]

[0074] Where J represents the moment of inertia of the wheel, measured in kgm. 2 ; The angular acceleration of the wheel, expressed in rad / m. 2 ;m w This represents 1 / 4 of the vehicle's mass, expressed in kg. Represents the longitudinal acceleration of a vehicle, measured in m / s². 2 ;T b F represents braking torque, with units of Nm; a This represents the air resistance experienced by the vehicle, measured in N.

[0075] 2.1.2) Determine the slip ratio dynamic model of the controlled vehicle.

[0076] For the longitudinal resistance F of the ground on the wheel w There are multiple models that can describe it, and the present invention adopts the following model for description:

[0077]

[0078] Where μ(λ) represents the vehicle's road adhesion coefficient (unitless); λ represents the vehicle's slip ratio (unitless); F z The force exerted on the wheel by the ground is represented by N; C1, C2 and C3 are shape parameters and have no unit.

[0079] Taking the derivative of the slip ratio λ, we have

[0080]

[0081] in, T represents the derivative of slip ratio with respect to time, and is dimensionless. bT represents the braking torque applied to the braked wheel, measured in Nm. In a hydraulic braking system, T b It can be represented in the following form:

[0082]

[0083] Where x represents the displacement of the brake master cylinder push rod inside the brake-by-wire device, in meters (m). R represents the speed of the push rod, in m / s. b Represents the radius from the brake caliper to the wheel hub, in meters (m); A b This represents the friction area of ​​the brake caliper, measured in meters (m²). 2 ;k p The pressure-master cylinder pushrod displacement coefficient is represented by MPa / m; u represents the displacement control input of the braking system, in meters; τ represents the inertia coefficient of the braking system, in 1 / s; t represents time, in seconds; d M This represents the disturbance input at the wheel end, measured in 1 / s; k in represents the control input gain, which is dimensionless; c represents the gain correction factor, with the unit being 1 / s.

[0084] 2.1.3) Based on the established tire dynamics model and slip ratio dynamics model, a slip ratio control system model oriented towards control is obtained.

[0085] make

[0086]

[0087] Here, f(x) and K represent two temporary substitutions, which facilitates the subsequent discussion.

[0088] Substituting the above substitutions into the vehicle tire dynamics model and slip ratio dynamics model, we get:

[0089]

[0090] Let x2 = x, x1 = λ. After the above simplification and substitution, the slip ratio control system model oriented towards control can be expressed as follows.

[0091]

[0092] Where u represents the displacement control input of the motor servo linear braking system, and the unit is m; and

[0093] d represents the derivatives of λ and x with respect to time, respectively, with units of 1 / s and m / s; W This represents the disturbance input at the braking system end, measured in m / s.

[0094] 2.1.4) Based on the control-oriented slip ratio control system model and the ground support force on the wheels of the controlled vehicle and the current road surface adhesion coefficient, the optimal slip ratio target value is calculated.

[0095] The slip rate tracking error of the system can be expressed as:

[0096] e1 = x1 - x 1d (9)

[0097] Where, x 1d =λ d e1 represents the target value of the optimal slip ratio; e1 represents the slip ratio tracking error, which is unitless.

[0098] Preferably, in step 2.2) above, based on the optimal slip ratio λ d The method for estimating the road surface adhesion coefficient using a preset performance control strategy, based on the current slip ratio λ of the controlled vehicle, includes the following steps:

[0099] 2.2.1) Based on the state response requirements of the slip ratio control system and the motor servo brake-by-wire system, i.e. the transient and steady-state characteristics of the system, select preset performance parameters and design preset performance functions.

[0100] To accurately constrain the transient and steady-state responses of the push rod displacement, a preset performance function is introduced as follows:

[0101]

[0102] Wherein, φ1(t) is a smooth function that satisfies the following condition:

[0103] a. φ1(t) is monotonically decreasing and φ1(t) > 0;

[0104] b. Under the initial conditions, φ1(0)>|e1(0)|;

[0105] c. The limit of the function as time approaches infinity. Existence, and

[0106] d、δ 10 ≥δ 1∞ >0,

[0107] Where, δ 10 δ 1∞ a1 and a1 represent the upper and lower boundaries of the pre-set reasonable shift rate control error and the convergence speed, respectively, all of which are unitless.

[0108] like Figure 3The figure shows the relationship between the preset performance function and the error of the controlled system. It can be seen that only the parameter δ needs to be designed according to the transient and steady-state performance requirements. 1∞ ,δ 10 ,a1 can be used to implement explicit constraints on the system's state performance.

[0109] 2.2.2) Based on the determined preset performance function, perform the first error transformation to obtain the intermediate control input x. 2d This allows for the constraint of system errors through a preset performance function.

[0110] The first error transformation is performed based on the slip ratio tracking error e1 and the smoothing function to obtain a new system error, denoted as the first transformation error z1, as follows:

[0111]

[0112] The first derivative of the first transformation error It can be represented as follows:

[0113]

[0114] in, and Let e1 be the slip ratio tracking error and e1 be the first derivative of the smooth function φ1(t), respectively; Ξ1 is an intermediate variable, denoted as Ξ1=φ1(t) / (φ1(t)-|e1|). 2 .

[0115] To design a stable and convergent controller, the following Lyapunov function for the first part is selected:

[0116]

[0117] in, x is the first derivative of the target value of the optimal slip ratio; 2d As an intermediate control input variable, and design the intermediate control input x. 2d for:

[0118]

[0119] Where, k NC11 k NC12 k NC13 All are control parameters greater than 0, β NC It is a positive control parameter. This represents the disturbance experienced by the vehicle.

[0120] 2.2.3) Based on the intermediate control input, a second error variable is calculated to obtain the road surface adhesion coefficient μ.

[0121] Specifically, the system error e2 is obtained based on the intermediate control input, and a second error transformation is performed to obtain the second transformed error z2 and its derivative. for:

[0122] e² = x² - x 2d (15)

[0123]

[0124]

[0125] Where Ξ2=φ2(t) / (φ2(t)-|e2|) 2 .

[0126] The Lyapunov function from the second part is selected and substituted into the controlled system model and error transformation as follows:

[0127]

[0128] The control inputs of the final designed system are as follows:

[0129]

[0130] The controller design is now complete. Applying the aforementioned control method, stable constrained transient and steady-state performance control can be achieved for the slip ratio of vehicles based on motor-servo-type automotive brake-by-wire systems. This enables accurate and efficient control of the vehicle's braking force.

[0131] Example 2

[0132] The above-described embodiment 1 provides a slip ratio control method for a brake-by-wire system. Correspondingly, this embodiment provides a slip ratio control system for a brake-by-wire system. The system provided in this embodiment can implement the slip ratio control method for a brake-by-wire system of embodiment 1. This system can be implemented through software, hardware, or a combination of both. For example, the system may include integrated or separate functional modules or units to execute the corresponding steps in the methods of embodiment 1. Since the system in this embodiment is basically similar to the method embodiment, the description process in this embodiment is relatively simple. Relevant details can be found in the description of embodiment 1. The system embodiment provided in this embodiment is merely illustrative.

[0133] This embodiment provides a slip ratio control system for a brake-by-wire system, including:

[0134] The activation judgment module is used to obtain the current vehicle slip ratio based on the collected vehicle speed and wheel speed of the controlled vehicle, and to determine whether slip ratio control needs to be activated. If activation is required, a signal is sent to the slip ratio control module; otherwise, a signal is sent to the regular control module.

[0135] The slip ratio control module is used to estimate the road surface adhesion coefficient based on a pre-built control-oriented slip ratio control system model and a preset performance control strategy.

[0136] The conventional control module is used to control the vehicle based on a pressure-position dual closed-loop control strategy by the vehicle's own motor servo-drive braking system using the estimated road adhesion coefficient.

[0137] Example 3

[0138] This embodiment provides a processing device corresponding to the slip ratio control method of the brake-by-wire system provided in Embodiment 1. The processing device can be a processing device for a client, such as a mobile phone, laptop, tablet computer, desktop computer, etc., to execute the method of Embodiment 1.

[0139] The processing device includes a processor, a memory, a communication interface, and a bus. The processor, memory, and communication interface are connected via the bus to enable communication between them. The memory stores a computer program that can run on the processor. When the processor runs the computer program, it executes the slip ratio control method for the brake-by-wire system provided in Embodiment 1.

[0140] In some embodiments, the memory may be high-speed random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage device.

[0141] In other embodiments, the processor can be a general-purpose processor of various types, such as a central processing unit (CPU) or a digital signal processor (DSP), and is not limited thereto.

[0142] Example 4

[0143] The slip ratio control method for the brake-by-wire system in Embodiment 1 can be specifically implemented as a computer program product. The computer program product may include a computer-readable storage medium on which computer-readable program instructions for executing the slip ratio control method for the brake-by-wire system described in Embodiment 1 are loaded.

[0144] A computer-readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination thereof.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A brake-by-wire vehicle slip ratio control method characterized by, The method comprises the following steps: Based on the collected vehicle speed, wheel speed and current road adhesion coefficient of the controlled vehicle, it is determined whether the slip ratio control needs to be activated: If it needs to be activated, the road adhesion coefficient is estimated based on the pre-constructed control-oriented slip ratio control system model and the preset performance control strategy, and the vehicle itself motor servo brake-by-wire system controls the controlled vehicle by using the estimated road adhesion coefficient; Otherwise, the vehicle itself motor servo brake-by-wire system controls the controlled vehicle by using the current road adhesion coefficient; The determination of whether the slip ratio control needs to be activated comprises: Based on the collected vehicle speed and wheel speed of the controlled vehicle, the current vehicle slip ratio is obtained; The current vehicle slip ratio is compared with the preset slip ratio control trigger threshold value, and if the slip ratio control trigger threshold value is greater than the current vehicle slip ratio, the slip ratio control mode is triggered; The estimation of the road adhesion coefficient based on the pre-constructed control-oriented slip ratio control system model and the preset performance control strategy comprises: The ground support force and the current road adhesion coefficient of the controlled vehicle wheel are collected to generate an optimal slip ratio target value; Based on the optimal slip ratio target value and the current slip ratio of the controlled vehicle, the road adhesion coefficient is estimated by using the preset performance control strategy; The estimation of the road adhesion coefficient based on the optimal slip ratio target value and the current slip ratio of the controlled vehicle by using the preset performance control strategy comprises: According to the state response requirements of the slip ratio control system and the motor servo brake-by-wire system, the preset performance parameters are selected, and the preset performance function is designed; Based on the determined preset performance function, a first error transformation is performed to obtain an intermediate control input quantity Thus, the system error is constrained by the preset performance function. Based on the determined preset performance function, a second error variable is obtained to obtain the road adhesion coefficient.

2. A brake-by-wire vehicle slip ratio control method according to claim 1, characterized by, The collection of the ground support force and the current road adhesion coefficient of the controlled vehicle wheel to generate the optimal slip ratio target value comprises: The force condition of the wheel of the controlled vehicle during operation is analyzed, and a tire dynamics model is established; The slip ratio dynamics model of the controlled vehicle is determined; Based on the established tire dynamics model and the slip ratio dynamics model, a control-oriented slip ratio control system model is obtained; Based on the control-oriented slip ratio control system model and the ground support force and the current road adhesion coefficient of the controlled vehicle wheel, the optimal slip ratio target value is calculated.

3. A brake-by-wire vehicle slip ratio control method according to claim 1, characterized by, The preset performance function is: wherein is a smooth function and satisfies the following conditions: a、 monotonically decreasing, and ; b. under initial conditions, ; c. Limit of a function as time approaches infinity There is, and ; d、 , ； wherein, , and respectively represent the upper bound, the lower bound and the convergence speed of the pre-set reasonable migration control error, all without unit.

4. A brake-by-wire vehicle slip ratio control method according to claim 1, characterized by, The input of the motor servo brake-by-wire system is: wherein, represents a displacement control input of the motor servo brake-by-wire system, in units of .

5. A brake-by-wire vehicle slip ratio control system characterized by, It comprises: An activation determination module is configured to determine whether the slip ratio control needs to be activated based on the collected vehicle speed, wheel speed and current road adhesion coefficient of the controlled vehicle, and if it needs to be activated, a signal is sent to a road adhesion coefficient estimation module, otherwise a signal is sent to a vehicle itself motor servo brake-by-wire system; A slip ratio control module is configured to estimate the road adhesion coefficient based on the pre-constructed control-oriented slip ratio control system model and the preset performance control strategy, and the vehicle itself motor servo brake-by-wire system controls the controlled vehicle by using the estimated road adhesion coefficient; A conventional control module is configured to control the controlled vehicle by using the current road adhesion coefficient by the vehicle itself motor servo brake-by-wire system. The judging whether the slip ratio control needs to be activated comprises: obtaining a current vehicle slip ratio based on the collected vehicle speed and wheel speed of the controlled vehicle; comparing the current vehicle slip ratio with a preset slip ratio control triggering threshold value, and triggering the slip ratio control mode if the slip ratio control triggering threshold value is greater than the current vehicle slip ratio; The estimation of the road adhesion coefficient based on the pre-constructed control-oriented slip ratio control system model and the preset performance control strategy comprises: collecting the ground support force and the current road adhesion coefficient of the controlled vehicle wheel to generate an optimal slip ratio target value; estimating the road adhesion coefficient based on the optimal slip ratio target value and the current slip ratio of the controlled vehicle by using the preset performance control strategy; The estimation of the road adhesion coefficient based on the optimal slip ratio target value and the current slip ratio of the controlled vehicle by using the preset performance control strategy comprises: selecting preset performance parameters according to the state response requirements of the slip ratio control system and the motor servo line control braking system, and designing a preset performance function; Based on the determined preset performance function, a first error transformation is performed to obtain an intermediate control input quantity Thus, the system error is constrained by the preset performance function. determining a second error variable based on the preset performance function to obtain the road adhesion coefficient.

6. A processing device comprising at least a processor and a memory having stored thereon a computer program, characterized in that, The processor executes the computer program to implement the steps of the slip ratio control method of the line control braking vehicle according to any one of claims 1 to 4.

7. A computer storage medium, characterized in that The computer readable instructions stored thereon can be executed by the processor to implement the steps of the slip ratio control method of the line control braking vehicle according to any one of claims 1 to 4.

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