An electric wheel brake chattering prediction control system and method thereof

Abstract

The application provides an electric wheel brake chatter prediction control system and method, which comprises a chatter prediction control unit, used for acquiring a desired braking force signal, a wheel angular velocity signal and a wheel hub motor angular velocity signal and predicting chatter, calculating wheel cylinder braking pressure and wheel hub motor compensation torque; and / or an electric wheel brake unit, interconnected with the chatter prediction control unit, used for controlling the action of the brake wheel cylinder and the wheel hub motor to suppress chatter. The electric wheel brake chatter prediction control system and method can actively predict the occurrence of chatter, avoid the chatter of the brake system by adjusting the hydraulic braking force, and compensate for the deficiency of the braking torque by the motor torque.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle chatter control, in particular to an electric wheel brake chatter prediction control system and method. BACKGROUND

[0002] With the continuous development of China's industrial technology, the demand for automobiles is increasing, leading to continuous improvement of automobile consumption level, and the safety and comfort of automobiles are increasingly valued by consumers. Among them, the chatter problem of the friction brake system of the automobile has always been the focus of consumers' concern. Traditionally, the chatter of the friction brake system of the automobile is mainly solved by improving the friction material performance of the brake system or changing the structural parameters of the vehicle. However, these methods belong to passive suppression technology and are relatively lagging. How to actively predict and control the chatter of the vehicle friction brake remains to be further studied. Therefore, there is an urgent need to design an electric wheel brake chatter prediction control system and method. SUMMARY

[0003] In order to solve the above problems, the purpose of the present application is to provide an electric wheel brake chatter prediction control system and method, which solves the technical problem of passive suppression by improving the friction material performance of the brake system or changing the structural parameters of the vehicle in the prior art, and is relatively lagging. It can actively predict the occurrence of chatter, avoid the chatter of the brake system by adjusting the hydraulic braking force, and compensate for the lack of braking torque by the motor torque at the same time.

[0004] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0005] As an aspect of the present application, an electric wheel brake chatter prediction control system is provided, comprising:

[0006] a chatter prediction control unit for obtaining a desired braking force signal, a wheel angular velocity signal and a hub motor angular velocity signal and predicting chatter, calculating wheel cylinder braking pressure and hub motor compensation torque; and / or

[0007] an electric wheel brake unit interconnected with the chatter prediction control unit for controlling the action of the brake wheel cylinder and the hub motor to suppress chatter.

[0008] As an electric wheel brake chatter prediction control system of the above aspect of the present application, the chatter prediction control unit comprises:

[0009] an information acquisition module for obtaining a desired braking force signal, a wheel angular velocity signal and a hub motor angular velocity signal; and / or

[0010] a chatter prediction module for predicting chatter according to the obtained desired braking force signal and wheel angular velocity signal, and outputting a wheel cylinder braking pressure signal to avoid chatter; and / or

[0011] a desired braking torque module configured to calculate a desired braking torque based on the received desired braking force signal; and / or

[0012] a hydraulic braking torque module configured to receive the wheel cylinder braking force signal from the chatter prediction module and calculate a hydraulic braking torque; and / or

[0013] a torque observer configured to observe the torque of the elastic connection between the wheel hub motor and the brake disc based on the wheel angular velocity and the wheel hub motor angular velocity; and / or

[0014] a motor compensation torque module configured to receive the signals from the desired braking torque module, the hydraulic braking torque module and the torque observer, calculate a wheel hub motor compensation torque, and transmit the wheel hub motor compensation torque to the drive motor controller.

[0015] As an electric wheel brake chatter prediction control system according to the above aspect of the present application, the information acquisition module comprises:

[0016] a wheel hub motor angular velocity sensor configured to obtain a wheel hub motor angular velocity signal; and / or

[0017] a wheel angular velocity sensor configured to obtain a wheel angular velocity signal; and / or

[0018] a microprocessor configured to process the wheel hub motor angular velocity signal and the wheel angular velocity signal, and communicate with the vehicle controller to obtain a desired braking force signal.

[0019] As an electric wheel brake chatter prediction control system according to the above aspect of the present application, the wheel hub motor braking unit comprises:

[0020] a brake wheel cylinder pressure controller configured to receive the wheel cylinder braking force signal from the chatter prediction module, and control the brake wheel cylinder to suppress chatter; and / or

[0021] a drive motor controller configured to receive the wheel hub motor compensation torque signal from the motor compensation torque module, and control the action of the wheel hub motor to compensate for the deficiency of the desired braking torque.

[0022] As another aspect of the present application, an electric wheel brake chatter prediction control method is provided, comprising the following steps:

[0023] S1. An information acquisition module acquires a wheel angular velocity signal and a wheel hub motor angular velocity signal, and communicates with a vehicle controller to obtain a desired braking force signal;

[0024] S2. A chatter prediction module predicts chatter based on the obtained desired braking force signal and the wheel angular velocity signal, outputs a wheel cylinder braking pressure signal to avoid chatter, and transmits the wheel cylinder braking pressure signal to a hydraulic braking torque module and a brake wheel cylinder pressure controller;

[0025] S3. The desired braking torque module calculates the desired braking torque according to the received desired braking pressure signal; the hydraulic braking torque module calculates the hydraulic braking torque according to the wheel cylinder braking pressure signal;

[0026] S4. The torque observer observes the torque of the elastic connecting part between the wheel hub motor and the brake disc and transmits to the motor compensation torque module to obtain the wheel hub motor compensation torque and transmit to the drive motor controller;

[0027] S5. The brake wheel cylinder pressure controller and the drive motor controller control the actions of the brake wheel cylinder and the wheel hub motor respectively according to the input signals to suppress the chatter.

[0028] As an electric wheel brake chatter prediction control method of the above aspect of the application, wherein S2 comprises the following steps:

[0029] S21. Establish a stability boundary curve with the wheel angular velocity and the desired braking pressure as the x-axis and y-axis respectively;

[0030] S22. Establish a coordinate point with the wheel angular velocity signal and the desired braking pressure signal as the x-axis value and y-axis value respectively;

[0031] S23. Compare the position of the coordinate point relative to the stability boundary curve, if the coordinate point is on the upper left side of the stability boundary curve, chatter will occur;

[0032] S24. Keep the x-axis value of the coordinate point unchanged, intercept a new coordinate point on the stability boundary curve, and take the y-axis value of the new coordinate point as the wheel cylinder braking pressure signal to avoid chatter;

[0033] S25. Transmit the wheel cylinder braking pressure signal to the hydraulic braking torque module and the brake wheel cylinder pressure controller.

[0034] As an electric wheel brake chatter prediction control method of the above aspect of the application, wherein the formula of the stability boundary curve in S21 is as follows:

[0035] a1-a2a3=0;

[0036] Wherein, a1, a2, a3 are three combination parameters, which are only to make the expression of the formula more concise, and the specific expression is as follows:

[0037] a1=(Ak x rσ0+Bk θ σ0 + Cd x k θ +Ck x d θ -k x kθ ) / Im;

[0038] a2=-(Amrσ1+BIσ1+CIm-ID x -md θ ) / Im;

[0039] a3=-Ck x k e / Im;

[0040] k x is the stiffness of the brake pad, r is the radius of the brake disc, k θ is the stiffness of the elastic connection, σ0 is the contact stiffness coefficient, d x is the damping of the brake pad, d θ is the damping of the elastic connection, m is the mass of the brake pad, σ1 is the contact damping coefficient, I is the moment of inertia of the brake disc;

[0041] A, B, C are three combined parameters in the expressions of a1, a2, a3, which are only for the sake of making the formula more concise, and their specific expressions are as follows:

[0042] A=(μ s -μ d )r 2 ω / (v s (μ s -μ d +μ d exp(ωr / v s )));

[0043] B=(μ s -μ d )rω / (v s (μ s -μ d +μ d exp(ωr / v s )));

[0044] C=-rσ0ω / (K p Nμ d +K p N(μ s -μ d )exp(-ωr / v s ));

[0045] wherein: μ s is the static friction coefficient, μ d is the dynamic friction coefficient, ω is the angular velocity of the wheel, v s is the Stribeck speed, K p is the brake pressure coefficient, and N is the hydraulic line pressure.

[0046] As an electric wheel brake chatter prediction control method of the above aspect of the application, the calculation formula of the expected brake torque in S3 is as follows:

[0047] F R = F N μ d ;

[0048] Wherein, F N is the wheel cylinder brake pressure, and μ d is the Coulomb friction coefficient.

[0049] As an electric wheel brake chatter prediction control method of the above aspect of the application, the specific calculation formula of the hydraulic brake torque in S3 is as follows:

[0050] F R ' = F N ' μ d ;

[0051] Wherein, F N ' is the wheel cylinder pressure to avoid chatter; and μ is the Coulomb friction coefficient.

[0052] As an electric wheel brake chatter prediction control method of the above aspect of the application, S4 comprises the following steps:

[0053] S41. The torque observer observes the torque of the elastic connecting part between the hub motor and the brake disc and transmits it to the motor compensation torque module;

[0054] S42. The motor compensation torque module compares the expected brake torque and the hydraulic brake torque to obtain the difference as the expected motor torque, and the difference between the expected motor torque and the observed torque signal is used as the input signal of the drive motor controller.

[0055] With the above technical scheme, the application has the following advantages:

[0056] The application provides an electric wheel brake chatter prediction control system and method, a chatter prediction control unit predicts chatter according to an obtained expected braking force signal and a wheel angular velocity signal, and outputs a wheel cylinder braking pressure signal; a wheel cylinder braking pressure controller controls brake wheel cylinder actuation according to the wheel cylinder braking pressure signal to suppress chatter; an expected braking torque module calculates an expected braking torque based on the expected braking force signal; a hydraulic braking torque module calculates a hydraulic braking torque according to the wheel cylinder braking pressure signal; a torque observer observes torque of an elastic connecting component between a wheel hub motor and a brake disc; a motor compensation torque module calculates wheel hub motor compensation torque according to the expected braking torque, the hydraulic braking torque and the torque observed by the torque observer, and delivers the wheel hub motor compensation torque to a drive motor controller to compensate for a deficiency of braking torque. The electric wheel brake chatter prediction control system and method can actively predict occurrence of chatter, avoid chatter of a braking system by adjusting hydraulic braking force, and compensate for a deficiency of braking torque by motor torque. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 Figure 1 is a structural diagram of the electric wheel brake chatter prediction control system of the application;

[0058] Figure 2 Figure 2 is a flowchart of the electric wheel brake chatter prediction control method of the application;

[0059] Figure 3 Figure 3 is a stability boundary curve of chatter prediction of the application;

[0060] Figure 4 Figure 4 is a phase trajectory diagram of the wheel hub motor braking unit in the embodiment of the application;

[0061] Figure 5 Figure 5 is a total braking torque time history diagram in the embodiment of the application. DETAILED DESCRIPTION

[0062] The technical solutions of the application are described in detail below in combination with the accompanying drawings of the specification. It should be noted that, in this document, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or sequence between the entities or operations. Moreover, the term “comprise”, “include” or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device.

[0063] Embodiment 1

[0064] First embodiment of the application Figure 1As shown, the embodiment provides an electric wheel brake chatter prediction control system, including a chatter prediction control unit for obtaining a desired braking force signal, a wheel angular velocity signal and a wheel hub motor angular velocity signal and predicting chatter, calculating a wheel cylinder braking pressure and a wheel hub motor compensation torque; and / or

[0065] An electric wheel brake unit is interconnected with the chatter prediction control unit for controlling the actions of the brake wheel cylinder and the wheel hub motor to suppress chatter.

[0066] The chatter prediction control unit includes:

[0067] The information acquisition module includes a wheel hub motor angular velocity sensor for obtaining a wheel hub motor angular velocity signal; an angular velocity sensor for obtaining a wheel angular velocity signal; a microprocessor for processing the wheel hub motor angular velocity signal and the wheel angular velocity signal; and a vehicle controller for obtaining a desired braking force signal; and / or

[0068] The chatter prediction module is used to predict chatter according to the obtained desired braking force signal and wheel angular velocity signal, and output a wheel cylinder braking pressure signal to avoid chatter; and / or

[0069] The desired braking torque module calculates a desired braking torque according to the received desired braking force signal; and / or

[0070] The hydraulic braking torque module receives the wheel cylinder braking force signal sent by the chatter prediction module and calculates a hydraulic braking torque; and / or

[0071] The torque observer observes the torque of the elastic connecting part between the wheel hub motor and the brake disc according to the wheel angular velocity and the wheel hub motor angular velocity; and / or

[0072] The motor compensation torque module receives signals transmitted by the desired braking torque module, the hydraulic braking torque module and the torque observer, calculates a wheel hub motor compensation torque, and transmits the wheel hub motor compensation torque to the drive motor controller.

[0073] The electric wheel brake unit includes:

[0074] The brake wheel cylinder pressure controller receives the wheel cylinder braking force signal transmitted by the chatter prediction module, and is used to control the brake wheel cylinder to suppress chatter; and / or

[0075] The drive motor controller receives the wheel hub motor compensation torque signal transmitted by the motor compensation torque module, and is used to control the action of the wheel hub motor to compensate for the deficiency of the desired braking torque.

[0076] The application discloses an electric wheel brake chatter prediction control system. A chatter prediction control unit predicts chatter according to an obtained expected braking force signal and a wheel angular velocity signal, and outputs a wheel cylinder braking pressure signal; a wheel cylinder braking pressure controller controls braking wheel cylinder actuation according to the wheel cylinder braking pressure signal to suppress chatter; an expected braking torque module calculates an expected braking torque based on the expected braking force signal; a hydraulic braking torque module calculates a hydraulic braking torque according to the wheel cylinder braking pressure signal; a torque observer observes torque of an elastic connecting part between a wheel hub motor and a brake disc; and a motor compensation torque module calculates wheel hub motor compensation torque according to the expected braking torque, the hydraulic braking torque and the torque observed by the torque observer, and transmits the wheel hub motor compensation torque to a drive motor controller to compensate for a deficiency of braking torque.

[0077] Embodiment 2

[0078] A second embodiment of the application Figure 2 As shown in the figure, the embodiment provides an electric wheel brake chatter prediction control method, comprising the following steps:

[0079] S1. An information acquisition module acquires a wheel angular velocity signal and a wheel hub motor angular velocity signal, and communicates with a vehicle controller to obtain an expected braking force signal;

[0080] S2. A chatter prediction module predicts chatter according to the obtained expected braking pressure signal and the wheel angular velocity signal, outputs a wheel cylinder braking pressure signal for avoiding chatter, and transmits the wheel cylinder braking pressure signal to a hydraulic braking torque module and a braking wheel cylinder pressure controller;

[0081] Specifically, S2 comprises the following steps:

[0082] S21. The wheel angular velocity and the expected braking pressure are taken as an x-axis and a y-axis respectively, and a stability boundary curve is established;

[0083] S22. A coordinate point is established by taking the wheel angular velocity signal and the expected braking pressure signal as an x-axis value and a y-axis value respectively;

[0084] S23. The position of the coordinate point relative to the stability boundary curve is compared, and if the coordinate point is on the upper left side of the stability boundary curve, chatter will occur;

[0085] S24. The x-axis value of the coordinate point is kept unchanged, a new coordinate point is obtained by intercepting the stability boundary curve, and the y-axis value of the new coordinate point is taken as the wheel cylinder braking pressure signal for avoiding chatter;

[0086] S25. The wheel cylinder braking pressure signal is transmitted to the hydraulic braking torque module and the braking wheel cylinder pressure controller.

[0087] In addition, the formula of the stability boundary curve in S21 is as follows:

[0088] a1-a2a3=0;

[0089] wherein a1, a2, a3 are three combination parameters, and the three combination parameters are only for making the expression of the formula more concise, and the specific expression is as follows:

[0090] a1 = -(Ak x rσ0+Bk θ σ0+Cd x k θ +Ck x d θ -k x k θ ) / Im;

[0091] a2 = -(Amrσ1+BIσ1+Cim-Id x -md θ ) / Im;

[0092] a3 = -Ck x k θ / Im;

[0093] k x is the stiffness of the brake block, r is the radius of the brake disc, k θ is the stiffness of the elastic connection, σ0 is the contact stiffness coefficient, d x is the damping of the brake block, d θ is the damping of the elastic connection, m is the mass of the brake block, σ1 is the contact damping coefficient, and I is the moment of inertia of the brake disc;

[0094] A, B, C are three combination parameters in the expressions of a1, a2, a3, and the three combination parameters are only for making the expression of the formula more concise, and the specific expression is as follows:

[0095] A = (μ s -μ d )r 2 ω / (v s (μ s -μ d +μ d exp(ωr / v s ))) ;

[0096] B = (μ s -μ d )rω / (v s (μ s -μ d +μ d ep(ωr / v s ))) ;

[0097] C = -rσ0ω / (K p Nμ d +Kp N(μ s -μ d )exp(-ωr / v s ));

[0098] wherein: μ s is the static friction coefficient, μ d is the dynamic friction coefficient, ω is the wheel angular velocity, v s is the Stribeck velocity, K p is the brake pressure coefficient, N is the hydraulic line pressure.

[0099] S3. The desired brake torque module calculates the desired brake torque according to the received desired brake pressure signal; the hydraulic brake torque module calculates the hydraulic brake torque according to the wheel cylinder brake pressure signal;

[0100] wherein the calculation formula of the desired brake torque in S3 is as follows:

[0101] F R =F N μ d ;

[0102] wherein F N is the wheel cylinder brake pressure, μ d is the Coulomb friction coefficient.

[0103] The specific calculation formula of the hydraulic brake torque in S3 is as follows:

[0104] F R ′=F N ′μ d ;

[0105] wherein F N ′ is the wheel cylinder pressure for avoiding chatter; μ is the Coulomb friction coefficient.

[0106] S4. The torque observer observes the torque of the elastic connecting part between the hub motor and the brake disc and transmits it to the motor compensation torque module to obtain the hub motor compensation torque and transmit it to the drive motor controller;

[0107] wherein S4 specifically comprises the following steps:

[0108] S41. The torque observer observes the torque of the elastic connecting part between the hub motor and the brake disc and transmits it to the motor compensation torque module;

[0109] S42. The motor compensation torque module compares the desired brake torque and the hydraulic brake torque to obtain the difference as the motor desired torque, and the difference between the motor desired torque and the observed torque signal is as the input signal of the drive motor controller.

[0110] S5. The brake wheel cylinder pressure controller and the drive motor controller control the actions of the brake wheel cylinder and the in-wheel motor respectively according to the input signals to suppress the chatter.

[0111] Embodiment 3

[0112] As shown in Figure 3 、 Figure 4 , the embodiment provides a method for predicting and controlling the chatter of the electric wheel brake, comprising the following steps:

[0113] S1, the information acquisition module obtains the expected brake pressure of 9N and the wheel angular velocity of 0.2 rad / s;

[0114] S2, the chatter prediction module predicts the chatter according to the obtained expected brake pressure and wheel angular velocity, outputs the wheel cylinder brake pressure signal to avoid the chatter, and transmits it to the hydraulic brake torque module and the brake wheel cylinder pressure controller, wherein the stability boundary curve of the chatter prediction is as shown in Figure 3 ;

[0115] S3, the expected brake torque module calculates the expected brake torque of 168 Nm according to the received wheel cylinder brake pressure signal, and transmits it to the motor compensation torque module; the hydraulic brake torque module calculates the hydraulic brake torque of 10 Nm, and transmits it to the motor compensation torque module.

[0116] S4. The elastic connection torque observer observes the torque signal and transmits it to the motor compensation torque module, obtains the in-wheel motor compensation torque, and transmits it to the drive motor controller and the brake wheel cylinder pressure control module to suppress the chatter.

[0117] S4 comprises the following specific steps:

[0118] S41. The torque observer observes the torque of the elastic connection component between the in-wheel motor and the brake disc and transmits it to the motor compensation torque module;

[0119] S42. The motor compensation torque module compares the expected brake torque and the hydraulic brake torque to obtain the difference as the motor expected torque, and the difference between the motor expected torque and the observed torque signal as the input signal of the drive motor controller.

[0120] S5. The brake wheel cylinder pressure controller and the drive motor controller control the actions of the brake wheel cylinder and the in-wheel motor respectively according to the input signals to suppress the chatter.

[0121] In step S2, the wheel angular velocity and the expected brake pressure are taken as the x-axis and the y-axis respectively to establish a stability boundary curve; the wheel angular velocity signal and the expected brake pressure signal are taken as the x-axis value and the y-axis value respectively to establish a coordinate point; the position of the coordinate point relative to the stability boundary curve is compared, and if the coordinate point is on the upper left side of the stability boundary curve, chatter will occur; the x-axis value of the coordinate point is kept unchanged, a new coordinate point is obtained by intercepting the stability boundary curve, and the y-axis value of the new coordinate point is taken as the wheel cylinder brake pressure signal to avoid chatter; the wheel cylinder brake pressure signal is transmitted to the hydraulic brake torque module and the brake wheel cylinder pressure controller. The stability boundary curve is obtained according to the following formula:

[0122] a1-a2a3=0;

[0123] wherein:

[0124] a1=-284444.4444A-384000B-C+1509.876543;

[0125] a2=-2.902511111*10 15 A-2.031071605*10 13 B-1.742222222*10 8 C+5.049540741 *10 11 ;

[0126] a3=-5.049540741*10 11 C;

[0127] wherein:

[0128] A=0.0675ω / (0.075+0.325exp(6.0ω));

[0129] B=0.45ω / (0.075+0.325exp(6.0ω));

[0130] C=-5.955*10^7ω / (0.325p+0.075pexp(-6.0ω));

[0131] wherein, ω is the wheel angular velocity.

[0132] Table 1 is the system parameters of the brake system, which are as follows:

[0133] Table 1 System Parameters

[0134]

[0135] From Figure 3It can be seen that the stability boundary curve a divides the parameter plane into two regions I and II, when the parameters are in the region I, the phase trajectory of the brake system converges to the stable equilibrium point eventually, and the brake system does not vibrate; when the parameters are in the region II, the phase trajectory of the brake system moves outside the limit cycle, and the brake system vibrates.

[0136] Figure 4 The phase trajectory diagram of the hub motor brake unit in the embodiment of the application is shown, Figure 4 wherein b represents using the torque observer, c represents not using the torque observer, e represents the stable equilibrium point, and f represents the vibration limit cycle. The angle difference is the difference between the hub motor angle and the wheel angle, and the angle difference derivative is the corresponding derivative. The initial state of the brake system is set to the vibration state, i.e., the phase trajectory moves along the vibration limit cycle f. By Figure 4 It can be seen that whether the torque observer is used or not, the phase trajectory of the brake system can be controlled from the vibration state of moving around the limit cycle to the state of not vibrating, i.e., converging to the stable equilibrium point e. Compared with the case of not using the torque observer c, when the torque observer b is used, the vibration amplitude of the brake system is significantly reduced.

[0137] Figure 5 The total brake torque time history diagram is shown in FIG. 6, Figure 5 wherein the m line represents the time history diagram of using the torque observer; and the n line represents the time history diagram of not using the torque observer. Figure 5 The initial state in FIG. 6 corresponds to Figure 4 The electric wheel brake vibration prediction control method of the application is started at the time of 3s. It can be seen from FIG. 6 that Figure 5 It can be seen that whether the torque observer is used or not, the total brake torque can converge to a stable value, i.e., the vibration can be avoided, and at the same time, when the torque observer is used, the peak value of the brake torque is 153.9Nm, and when the torque observer is not used, the peak value of the brake torque is 315Nm, which shows that the torque observer can better suppress the impact caused by the response lag of the hydraulic brake and the motor brake in the control process.

[0138] Finally, it should be pointed out that although the application has been described with reference to the current specific embodiments, those skilled in the art should recognize that the above embodiments are only used to illustrate the application, and are not used as a limitation on the application, and various equivalent changes or replacements can be made without departing from the concept of the application, therefore, any changes or modifications of the above embodiments within the scope of the spirit of the application will fall within the scope of the claims of the application.

Claims

1. An electrically motorized wheel brake chatter prediction control system, characterized by, The application relates to an electric wheel brake system, comprising: a chatter prediction control unit for obtaining a desired braking force signal, a wheel angular velocity signal and a wheel hub motor angular velocity signal and predicting chatter, calculating wheel cylinder braking pressure and wheel hub motor compensation torque; an electric wheel brake unit interconnected with the chatter prediction control unit for controlling the actions of the brake wheel cylinder and the wheel hub motor to suppress chatter; the chatter prediction control unit comprises: an information acquisition module for obtaining a desired braking force signal, a wheel angular velocity signal and a wheel hub motor angular velocity signal; the information acquisition module comprises: a wheel hub motor angular velocity sensor for obtaining a wheel hub motor angular velocity signal; an angular velocity sensor for obtaining a wheel angular velocity signal; a microprocessor for processing the wheel hub motor angular velocity signal and the wheel angular velocity signal, and communicating with a vehicle controller to obtain a desired braking force signal; a chatter prediction module for predicting chatter according to the obtained desired braking force signal and the wheel angular velocity signal, and outputting a wheel cylinder braking pressure signal for avoiding chatter, wherein the wheel angular velocity and the desired braking pressure are taken as the x-axis and the y-axis respectively, and a stability boundary curve is established; the formula of the stability boundary curve is as follows: ； wherein a 1, a 2, a 3 are three combined parameters, the specific expressions of which are as follows: ； ； ； Kb as the stiffness of the brake pad, Rd as the radius of the brake disc, Kc as the stiffness of the elastic connection, Kt as the contact stiffness coefficient, Cp as the damping of the brake pad, Cc as the damping of the elastic connection, Mp as the mass of the brake pad, Ct as the contact damping coefficient, Jd as the moment of inertia of the brake disc; A, B, C are a 1, a 2, a 3 three combination parameters in the expression, the three combination parameters are only for making the expression of the formula more concise, and the specific expression is as follows: ； ； ； wherein: is the static friction coefficient, is the dynamic friction coefficient, is the wheel angular velocity, is the Stribeck velocity, is the brake pressure coefficient, is the hydraulic line pressure; a desired braking torque module for calculating a desired braking torque according to the received desired braking force signal; a hydraulic braking torque module for receiving the wheel cylinder braking force signal sent by the chatter prediction module and calculating a hydraulic braking torque; a torque observer for observing the torque of the elastic connecting component between the wheel hub motor and the brake disc according to the wheel angular velocity and the wheel hub motor angular velocity; a motor compensation torque module for receiving the signals transmitted by the desired braking torque module, the hydraulic braking torque module and the torque observer, calculating a wheel hub motor compensation torque, and transmitting the wheel hub motor compensation torque to a drive motor controller.

2. The electrically driven wheel brake chattering prediction control system according to claim 1, characterized in that, the electric wheel brake unit comprises: a brake wheel cylinder pressure controller for receiving the wheel cylinder braking force signal transmitted by the chatter prediction module, and controlling the brake wheel cylinder to suppress chatter; a drive motor controller for receiving the wheel hub motor compensation torque signal transmitted by the motor compensation torque module, and controlling the action of the wheel hub motor to compensate for the deficiency of the desired braking torque.

3. An electrically powered wheel brake chattering prediction control method, characterized by, The application further discloses an electric wheel brake method, comprising the following steps: S1. the information acquisition module acquires the wheel angular velocity signal and the wheel hub motor angular velocity signal, and communicates with the vehicle controller to obtain the desired braking force signal; S2. the chatter prediction module predicts chatter according to the obtained desired braking force signal and the wheel angular velocity signal, outputs the wheel cylinder braking pressure signal for avoiding chatter, and transmits the wheel cylinder braking pressure signal to the hydraulic braking torque module and the brake wheel cylinder pressure controller; the S2 comprises the following steps: S21. the wheel angular velocity and the desired braking pressure are taken as the x-axis and the y-axis respectively, and a stability boundary curve is established; the formula of the stability boundary curve in the S21 is as follows: ； wherein a 1, a 2, a 3 are three combined parameters, the specific expressions of which are as follows: ； ； ； Kb for the stiffness of the brake pad, Rb for the radius of the brake disc, Kc for the stiffness of the elastic connection, Kt for the contact stiffness coefficient, Cp for the damping of the brake pad, Cc for the damping of the elastic connection, Mp for the mass of the brake pad, Ct for the contact damping coefficient, Jb for the moment of inertia of the brake disc; A, B, C are a 1, a 2, a 3 three combination parameters in the expression, the three combination parameters are only to make the expression of the formula more concise, and the specific expression is as follows: ； ； ； wherein: is the static friction coefficient, is the dynamic friction coefficient, is the wheel angular velocity, is the Stribeck velocity, is the brake pressure coefficient, is the hydraulic line pressure; S22. the wheel angular velocity signal and the desired braking pressure signal are taken as the x-axis value and the y-axis value respectively, and a coordinate point is established; S23. the position of the coordinate point relative to the stability boundary curve is compared, and if the coordinate point is on the upper left side of the stability boundary curve, chatter will occur. S24. Keep the x-axis value of the coordinate point unchanged, intercept a new coordinate point on the stability boundary curve, and take the y-axis value of the new coordinate point as the wheel cylinder brake pressure signal to avoid chattering; S25. The wheel cylinder brake pressure signal is transmitted to the hydraulic brake torque module and the brake wheel cylinder pressure controller; S3. The expected brake torque module calculates the expected brake torque according to the received expected brake pressure signal; the hydraulic brake torque module calculates the hydraulic brake torque according to the wheel cylinder brake pressure signal; S4. The torque observer observes the torque of the elastic connecting component between the hub motor and the brake disc and transmits it to the motor compensation torque module, obtains the hub motor compensation torque, and transmits it to the drive motor controller; S5. The brake wheel cylinder pressure controller and the drive motor controller control the actions of the brake wheel cylinder and the hub motor respectively according to the input signals to suppress chattering.

4. The electrically driven wheel brake chattering prediction control method according to claim 3, characterized in that, The calculation formula of the expected brake torque in S3 is as follows: ； wherein is the wheel cylinder brake pressure, is the Coulomb friction coefficient.

5. The electrically driven wheel brake chattering prediction control method according to claim 3, characterized in that, The specific calculation formula of the hydraulic brake torque in S3 is as follows: ； wherein to avoid chattering of the wheel cylinder pressure; is the Coulomb friction coefficient.

6. The electrically driven wheel brake chattering prediction control method according to claim 3, characterized in that, S4 includes the following steps: S41. The torque observer observes the torque of the elastic connecting component between the hub motor and the brake disc and transmits it to the motor compensation torque module; S42. The motor compensation torque module compares the expected brake torque and the hydraulic brake torque to obtain the difference as the motor expected torque, and the difference between the motor expected torque and the observed torque signal is taken as the input signal of the drive motor controller.

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