Actuator intelligent failure estimation and safety guarantee system for composite braking system

Abstract

The invention discloses an actuator intelligent failure estimation and safety guarantee system for a composite braking system. Comprising a composite brake-by-wire system actuator state information acquisition module, an electronic mechanical braking system actuator state evaluation module, a regenerative braking system actuator state evaluation module, a composite brake-by-wire system actuator safety state judgment module and a safety guarantee module. The composite brake-by-wire system actuator state information acquisition module is used for acquiring actuator state information of an electronic mechanical braking system and a regenerative braking system; the electromechanical braking system actuator state evaluation module is used for calculating an electromechanical braking system actuator failure estimation factor; the regenerative braking system actuator state evaluation module is used for calculating a regenerative braking system actuator failure estimation factor; the composite brake-by-wire system actuator safety state judgment module is used for judging the safety state of the actuator; and the safety guarantee module executes corresponding safety guarantee measures according to the safety state of the actuator.

Description

Technical Field

[0001] The present invention belongs to the field of automobile safety, relates to electric vehicle safety control technology, and specifically relates to an actuator intelligent failure prediction and safety assurance system for a composite braking system. Background Art

[0002] With the rapid development of automobile intelligence and electrification, the composite wire control brake system composed of an electromechanical brake system and a regenerative brake system has attracted widespread attention. The composite wire control brake system controls the vehicle's braking process through electronic signals, replacing the traditional hydraulic brake system, and has the advantages of fast response speed, high control accuracy and high system integration.

[0003] The electromechanical brake system uses electronic signals to perform braking operations, and its core component is the electromechanical brake actuator. The performance of this actuator directly affects the braking effect and safety of the vehicle. However, during long-term use, the electromechanical brake actuator may fail due to factors such as electrical performance degradation, mechanical wear, thermal management problems, or changes in the external environment. The regenerative braking system recycles braking energy by converting it into electrical energy, but its mechanical properties, electrical properties, thermal properties, and braking efficiency may be affected by various factors, resulting in system failure.

[0004] In the prior art, the failure prediction and safety assurance measures for the actuators of the composite wire control brake system are still not perfect. In addition, the existing safety assurance measures are mostly passive responses, and fail to take the initiative to prevent and grade the risk of actuator failure. Therefore, there is an urgent need for a system that can comprehensively evaluate the failure risk of the actuators of the composite wire control brake system and provide multi-level safety assurance measures to improve the safety and reliability of the composite wire control brake system. Summary of the invention

[0005] The purpose of the present invention is to provide an intelligent failure prediction and safety assurance system for actuators of a composite brake system, so as to solve the problems faced in the above-mentioned background technology.

[0006] In order to achieve the above object, the present invention provides the following scheme:

[0007] An actuator intelligent failure prediction and safety assurance system for a composite brake system, comprising a composite wire control brake system actuator state information acquisition module, an electromechanical brake system actuator state evaluation module, a regenerative brake system actuator state evaluation module, a composite wire control brake system actuator safety state judgment module and a safety assurance module;

[0008] The composite brake-by-wire system actuator state information acquisition module is used to obtain state information of the electromechanical brake system actuator and the regenerative brake system actuator, and provide the electromechanical brake system actuator state evaluation module and the regenerative brake system actuator state evaluation module with information sources required for state evaluation;

[0009] The electronic mechanical brake system actuator state assessment module uses a long short-term memory network algorithm to calculate the failure prediction factor of the electronic mechanical brake system actuator according to the electrical performance index of the electronic mechanical brake system actuator, the mechanical structure and component state index of the electronic mechanical brake system actuator, the thermal management and heat dissipation capacity index of the electronic mechanical brake system actuator, and the external environment index of the electronic mechanical brake system actuator;

[0010] The calculation formula of the failure prediction factor of the electronic mechanical brake system actuator is:

[0011]

[0012] In the formula, is the state input vector of the electronic mechanical brake system actuator of the i-th wheel at time t, i=1, 2, 3, 4 represent the left front wheel, right front wheel, left rear wheel and right rear wheel respectively; is the normalized state input vector of the electromechanical brake system actuator of the i-th wheel at time t; is the electrical performance index of the electromechanical brake system actuator of the i-th wheel at time t; is the mechanical structure and component status index of the electronic mechanical brake system actuator of the i-th wheel at time t; is the thermal management and heat dissipation capability index of the electronic mechanical brake system actuator of the i-th wheel at the moment; is the external environment index of the electronic mechanical brake system actuator of the i-th wheel at time t; is the hidden state of the failure prediction of the actuator of the electronic mechanical brake system of the i-th wheel at time t-1; is the memory unit state of the failure prediction of the actuator of the electromechanical brake system of the i-th wheel at time t; is the memory unit state of the failure prediction of the actuator of the electronic mechanical brake system of the i-th wheel at time t-1; and is the weight matrix for predicting the failure of the actuator of the electromechanical brake system of the i-th wheel; and is the bias term for failure prediction of the electronic mechanical brake system actuator of the i-th wheel; σ is the sigmoid activation function; tanh is the hyperbolic tangent activation function; is the failure prediction factor of the electronic mechanical brake system actuator of the i-th wheel at time t, and its value range is between 0 and 1;

[0013] The regenerative braking system actuator state evaluation module calculates the regenerative braking system actuator failure prediction factor using a long short-term memory network algorithm based on the mechanical performance index of the regenerative braking system actuator, the electrical performance index of the regenerative braking system actuator, the thermal performance index of the regenerative braking system actuator, and the braking efficiency index of the regenerative braking system actuator;

[0014] The calculation formula of the regenerative braking system actuator failure prediction factor is:

[0015]

[0016] In the formula, is the state input vector of the regenerative braking system actuator of the i-th wheel at time t, i=1, 2, 3, 4 represent the left front wheel, right front wheel, left rear wheel and right rear wheel respectively; is the normalized state input vector of the regenerative braking system actuator of the i-th wheel at time t; is the mechanical performance index of the regenerative braking system actuator of the i-th wheel at time t; is the electrical performance index of the regenerative braking system actuator of the i-th wheel at time t; is the thermal performance index of the regenerative braking system actuator of the i-th wheel at time t; is the braking efficiency index of the regenerative braking system actuator of the i-th wheel at time t; is the hidden state of the regenerative braking system actuator failure prediction of the i-th wheel at time t-1; is the memory unit state of the regenerative braking system actuator failure prediction of the i-th wheel at time t; is the memory unit state of the regenerative braking system actuator failure prediction of the i-th wheel at time t-1; and is the weight matrix for predicting the failure of the regenerative braking system actuator of the i-th wheel; and is the bias term for failure prediction of the regenerative braking system actuator of the i-th wheel; σ is the sigmoid activation function; tanh is the hyperbolic tangent activation function; is the failure prediction factor of the regenerative braking system actuator of the i-th wheel at time t, and its value range is between 0 and 1;

[0017] The composite brake-by-wire system actuator safety state judgment module determines the composite brake-by-wire system actuator safety state judgment coefficient according to the electromechanical brake system actuator failure prediction factor and the regenerative brake system actuator failure prediction factor; the composite brake-by-wire system actuator safety state judgment coefficient is used to judge the safety state of the composite brake-by-wire system actuator;

[0018] The calculation formula of the safety state judgment coefficient of the composite brake-by-wire system actuator is:

[0019]

[0020] In the formula, is the failure prediction factor of the electronic mechanical brake system actuator of the i-th wheel at time t, where i=1, 2, 3, 4 represent the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively; is the failure prediction factor of the regenerative braking system actuator of the i-th wheel at time t; is the safety state judgment coefficient of the composite brake-by-wire system actuator of the i-th wheel at time t; the specific meaning of the calculation formula of the safety state judgment coefficient of the composite brake-by-wire system actuator is: and When , it indicates that the electronic mechanical brake system executive motor and the regenerative brake system hub motor of the i-th wheel at time t are in normal working condition; when and When , it indicates that the actuator motor of the electronic mechanical brake system of the i-th wheel at time t is in a critical failure state, while the wheel hub motor of the regenerative brake system is in a normal working state; when and When , it indicates that the wheel hub motor of the regenerative braking system of the i-th wheel at time t is in a critical failure state, while the actuator motor of the electronic mechanical braking system is in a normal working state; when and When , it indicates that the electronic mechanical brake system executive motor and the regenerative brake system hub motor of the i-th wheel at time t are both in a critical failure state;

[0021] The safety assurance module executes corresponding safety assurance measures according to the value of the safety state judgment coefficient of the composite wire control brake system actuator; the safety assurance measures include first-level safety assurance measures, second-level safety assurance measures, third-level safety assurance measures, fourth-level safety assurance measures and fifth-level safety assurance measures.

[0022] The calculation formula of the electrical performance index of the electromechanical brake system actuator is:

[0023]

[0024] In the formula, xEec It is the electrical performance index of the actuator of the electromechanical brake system; E Current of the motor that executes the electromechanical brake system; V E Input voltage to the motor for the electromechanical brake system; τ E The delay time for the motor to run for the electromechanical brake system; E is the electromagnetic interference level of the electric motor of the electronic mechanical brake system; α1, α2, α3 and α4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0025] The calculation formula of the mechanical structure and component status index of the electromechanical brake system actuator is:

[0026]

[0027] In the formula, x Emc It is the mechanical structure and component status indicator of the electromechanical brake system actuator; W Ebea The bearing wear of the motor for the electromechanical brake system; L Eg Fatigue life of the transmission gear tooth surface of the motor for the electronic mechanical brake system; A vib Vibration amplitude of the motor for the electromechanical brake system; E n is the noise level of the motor executing the electronic mechanical brake system; β1, β2, β3 and β4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0028] The calculation formula for the thermal management and heat dissipation capability index of the electromechanical brake system actuator is:

[0029]

[0030] In the formula, x Ett It is the thermal management and heat dissipation capability index of the electronic mechanical brake system actuator; T Er The rotor temperature of the motor that executes the electromechanical brake system; T Es The stator temperature of the motor that performs the electromechanical brake system; T Eh The housing temperature of the motor that performs the electromechanical brake system; η Ec is the cooling system efficiency of the electronic mechanical brake system actuator; ε1, ε2 and ε3 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0031] The calculation formula of the external environment index of the electronic mechanical brake system actuator is:

[0032]

[0033] In the formula, x EeIt is the external environment index of the electronic mechanical brake system actuator; T Ee The ambient temperature of the motor of the electronic mechanical brake system; H Ee The humidity of the environment where the motor of the electronic mechanical brake system is located; D Ee The dust concentration in the environment where the motor of the electronic mechanical brake system is located; C Ec Metal corrosion rates of winding wires in motors that perform electromechanical brake systems; and is the weight coefficient, and its specific value is determined through simulation and experiments.

[0034] The calculation formula of the mechanical performance index of the regenerative braking system actuator is:

[0035]

[0036] Where x Im It is the mechanical performance index of the regenerative braking system actuator; t Ires is the response time of the hub motor; A Ivib is the vibration amplitude of the hub motor; I n is the noise level of the hub motor; W Ib is the wear amount of the hub motor bearing; ω1, ω2, ω3 and ω4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0037] The calculation formula of the electrical performance index of the regenerative braking system actuator is:

[0038]

[0039] In the formula, x Ie It is the electrical performance index of the regenerative braking system actuator; I Bcm is the maximum operating current of the hub motor; V Bm is the maximum operating voltage of the hub motor; R Ins is the insulation resistance of the hub motor winding; ρ1, ρ2, ρ3 and ρ4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0040] The calculation formula of the thermal performance index of the regenerative braking system actuator is:

[0041]

[0042] In the formula, x It It is the thermal performance index of the regenerative braking system actuator; Q Ia is the heat accumulation of the hub motor; T Is is the shell temperature of the hub motor; T Ic is the coolant temperature of the hub motor; vIc is the coolant flow rate of the hub motor; ζ1, ζ2, ζ3 and ζ4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0043] The calculation formula of the braking efficiency index of the regenerative braking system actuator is:

[0044]

[0045] In the formula, x Ire It is the braking efficiency index of the regenerative braking system actuator; P Ire is the regenerative braking power of the hub motor; I Ire is the regenerative braking current of the hub motor; T Ire is the regenerative braking torque of the hub motor; η Ire is the regenerative braking energy recovery rate of the hub motor; λ1, λ2, λ3 and λ4 are weight coefficients, and their specific values ​​are determined through simulation and experiments.

[0046] The execution condition of the first-level safety guarantee measure is: the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the four wheels at the current moment are all equal to 0; the first-level safety guarantee measure is specifically: the vehicle completes the braking process normally, and no intervention is required on the vehicle;

[0047] The execution condition of the second-level safety guarantee measure is: at the current moment, the value of the safety state judgment coefficient of the composite wire control brake system actuator of only one wheel is equal to 1, while the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the other three wheels are all equal to 0; the second-level safety guarantee measure is specifically: using the failure prediction factor of the electronic mechanical brake system actuator to calculate the first advance opening time for regenerative braking compensation of the wheel corresponding to the critical failure state of the electronic mechanical brake system actuator motor; making the regenerative braking torque of the wheel corresponding to the critical failure state of the electronic mechanical brake system actuator motor equal to the mechanical braking torque generated when the electronic mechanical brake system actuator motor is in the critical failure state; if the regenerative braking torque of the wheel hub motor corresponding to the critical failure state of the electronic mechanical brake system actuator motor cannot meet the mechanical braking torque demand, then the insufficient mechanical braking torque is evenly distributed to the two wheels on the same axle whose values ​​of the safety state judgment coefficients of the composite wire control brake system actuator are both equal to 0, and compensated by the electronic mechanical brake system;

[0048] The calculation formula of the first advance opening time is:

[0049] t1=y E ·(t Icst +t Imdr +t Ier +t Imr +tIfa )

[0050] Where, t1 is the first advance opening time; y E is the failure prediction factor of the electronic mechanical brake system actuator; t Icst is the transmission time of the wheel hub motor control signal; t Imdr is the response time of the wheel hub motor driver; t Ier is the electromagnetic response time of the hub motor; t Imr is the mechanical response time of the hub motor; t Ifa Adjust timing for in-wheel motor control feedback and closed loop.

[0051] The execution condition of the third-level safety guarantee measure is: at the current moment, the value of the safety state judgment coefficient of the composite wire control brake system actuator of only one wheel is equal to 2, and the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the other three wheels are all equal to 0; the third-level safety guarantee measure is specifically: using the regenerative braking system actuator failure estimation factor to calculate the second advance start time of mechanical braking compensation for the wheel corresponding to the critical failure state of the regenerative braking system hub motor; making the mechanical braking torque of the wheel corresponding to the critical failure state of the regenerative braking system hub motor equal to the regenerative braking torque generated when the regenerative braking system hub motor is in the critical failure state;

[0052] The calculation formula of the second advance opening time is:

[0053] t2=y I ·(t Esp +t Ecc +t Ead +t Emr +t Efa )

[0054] Where, t2 is the second advance opening time; y I is the failure prediction factor of the regenerative braking system actuator; t Esp is the signal processing time of the electronic mechanical brake system; t Ecc Calculation time for the electronic mechanical brake system controller; t Ead The motor driving time for the electromechanical brake system; t Emr The mechanical response time of the motor for the electromechanical brake system; t Efa Perform motor control feedback and closed-loop adjustment timing for electromechanical brake systems.

[0055] The execution condition of the fourth-level safety guarantee measure is: at the current moment, the value of the safety state judgment coefficient of the composite wire control brake system actuator of only one wheel is equal to 3, while the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the other three wheels are all equal to 0; the fourth-level safety guarantee measure is specifically: using the failure prediction factor of the electronic mechanical braking system actuator and the failure prediction factor of the regenerative braking system actuator to calculate the third advance start time of the regenerative braking compensation of the same-side wheel corresponding to the wheel where the electronic mechanical braking system execution motor and the regenerative braking system hub motor are both in a critical failure state; making the regenerative braking torque of the same-side wheel equal to the total braking torque of the wheel corresponding to the electronic mechanical braking system execution motor and the regenerative braking system hub motor are both in a critical failure state; if the regenerative braking torque of the same-side wheel cannot meet the total braking torque requirement, the insufficient total braking torque is compensated by the electronic mechanical braking system of the same-side wheel;

[0056] The calculation formula of the third advance opening time is:

[0057] t3=max(y E ,y I )·(t Icst +t Imdr +t Ier +t Imr +t Ifa )

[0058] Where, t3 is the third advance opening time; y E is the failure prediction factor of the electronic mechanical brake system actuator; I is the failure prediction factor of the regenerative braking system actuator; t Icst is the transmission time of the wheel hub motor control signal; t Imdr is the response time of the wheel hub motor driver; t Ier is the electromagnetic response time of the hub motor; t Imr is the mechanical response time of the hub motor; t Ifa Adjust timing for wheel hub motor control feedback and closed loop;

[0059] The execution condition of the fifth-level safety protection measures is: at the current moment, the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of two or more wheels are not equal to 0; the fifth-level safety protection measures are specifically: adopting redundant mechanical braking or redundant hydraulic braking to achieve safe stopping of the vehicle.

[0060] The beneficial effects of the present invention are:

[0061] The present invention uses a long short-term memory network algorithm to achieve actuator failure prediction by comprehensively analyzing the state information of the electronic mechanical brake system and the regenerative brake system actuator, which is conducive to timely discovering potential faults and abnormal conditions and improving the safety of the composite wire control brake system. In addition, the present invention determines the safety state of the composite wire control brake system actuator according to the actuator failure prediction situation, and implements corresponding safety protection measures in a graded manner, ensuring that effective safety responses can be provided under different fault severity levels. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The present invention will be further described below in conjunction with the accompanying drawings:

[0063] Figure 1 The present invention proposes an actuator intelligent failure prediction and safety assurance system for a composite braking system. DETAILED DESCRIPTION

[0064] The present invention is further described in detail below based on the accompanying drawings and specific embodiments.

[0065] See also Figure 1 The intelligent failure prediction and safety assurance system for the actuator of the composite brake system of the present invention comprises a composite wire control brake system actuator state information acquisition module, an electromechanical brake system actuator state evaluation module, a regenerative brake system actuator state evaluation module, a composite wire control brake system actuator safety state judgment module and a safety assurance module;

[0066] The composite brake-by-wire system actuator state information acquisition module is used to obtain state information of the electromechanical brake system actuator and the regenerative brake system actuator, and provide the electromechanical brake system actuator state evaluation module and the regenerative brake system actuator state evaluation module with information sources required for state evaluation;

[0067] The electronic mechanical brake system actuator state assessment module uses a long short-term memory network algorithm to calculate the failure prediction factor of the electronic mechanical brake system actuator according to the electrical performance index of the electronic mechanical brake system actuator, the mechanical structure and component state index of the electronic mechanical brake system actuator, the thermal management and heat dissipation capacity index of the electronic mechanical brake system actuator, and the external environment index of the electronic mechanical brake system actuator;

[0068] The calculation formula of the failure prediction factor of the electronic mechanical brake system actuator is:

[0069]

[0070] In the formula, is the state input vector of the electronic mechanical brake system actuator of the i-th wheel at time t, i=1, 2, 3, 4 represent the left front wheel, right front wheel, left rear wheel and right rear wheel respectively; is the normalized state input vector of the electromechanical brake system actuator of the i-th wheel at time t; is the electrical performance index of the electromechanical brake system actuator of the i-th wheel at time t; is the mechanical structure and component status index of the electronic mechanical brake system actuator of the i-th wheel at time t; is the thermal management and heat dissipation capability index of the electronic mechanical brake system actuator of the i-th wheel at time t; is the external environment index of the electronic mechanical brake system actuator of the i-th wheel at time t; is the hidden state of the failure prediction of the actuator of the electronic mechanical brake system of the i-th wheel at time t-1; is the memory unit state of the failure prediction of the actuator of the electromechanical brake system of the i-th wheel at time t; is the memory unit state of the failure prediction of the actuator of the electronic mechanical brake system of the i-th wheel at time t-1; and is the weight matrix for predicting the failure of the actuator of the electromechanical brake system of the i-th wheel; and is the bias term for failure prediction of the electronic mechanical brake system actuator of the i-th wheel; σ is the sigmoid activation function; tanh is the hyperbolic tangent activation function; is the failure prediction factor of the electronic mechanical brake system actuator of the i-th wheel at time t, and its value range is between 0 and 1;

[0071] The regenerative braking system actuator state evaluation module calculates the regenerative braking system actuator failure prediction factor using a long short-term memory network algorithm based on the mechanical performance index of the regenerative braking system actuator, the electrical performance index of the regenerative braking system actuator, the thermal performance index of the regenerative braking system actuator, and the braking efficiency index of the regenerative braking system actuator;

[0072] The calculation formula of the regenerative braking system actuator failure prediction factor is:

[0073]

[0074] In the formula, is the state input vector of the regenerative braking system actuator of the i-th wheel at time t, i=1, 2, 3, 4 represent the left front wheel, right front wheel, left rear wheel and right rear wheel respectively; is the normalized state input vector of the regenerative braking system actuator of the i-th wheel at time t; is the mechanical performance index of the regenerative braking system actuator of the i-th wheel at time t; is the electrical performance index of the regenerative braking system actuator of the i-th wheel at time t; is the thermal performance index of the regenerative braking system actuator of the i-th wheel at time t; is the braking efficiency index of the regenerative braking system actuator of the i-th wheel at time t; is the hidden state of the regenerative braking system actuator failure prediction of the i-th wheel at time t-1; is the memory unit state of the regenerative braking system actuator failure prediction of the i-th wheel at time t; is the memory unit state of the regenerative braking system actuator failure prediction of the i-th wheel at time t-1; and is the weight matrix for predicting the failure of the regenerative braking system actuator of the i-th wheel; and is the bias term for failure prediction of the regenerative braking system actuator of the i-th wheel; σ is the sigmoid activation function; tanh is the hyperbolic tangent activation function; is the failure prediction factor of the regenerative braking system actuator of the i-th wheel at time t, and its value range is between 0 and 1;

[0075] The composite brake-by-wire system actuator safety state judgment module determines the composite brake-by-wire system actuator safety state judgment coefficient according to the electromechanical brake system actuator failure prediction factor and the regenerative brake system actuator failure prediction factor; the composite brake-by-wire system actuator safety state judgment coefficient is used to judge the safety state of the composite brake-by-wire system actuator;

[0076] The calculation formula of the safety state judgment coefficient of the composite brake-by-wire system actuator is:

[0077]

[0078] In the formula, is the failure prediction factor of the electronic mechanical brake system actuator of the i-th wheel at time t, where i=1, 2, 3, 4 represent the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively; is the failure prediction factor of the regenerative braking system actuator of the i-th wheel at time t; is the safety state judgment coefficient of the composite brake-by-wire system actuator of the i-th wheel at time t; the specific meaning of the calculation formula of the safety state judgment coefficient of the composite brake-by-wire system actuator is: and When , it indicates that the electronic mechanical brake system executive motor and the regenerative brake system hub motor of the i-th wheel at time t are in normal working condition; when and When , it indicates that the actuator motor of the electronic mechanical brake system of the i-th wheel at time t is in a critical failure state, while the wheel hub motor of the regenerative brake system is in a normal working state; when and When , it indicates that the wheel hub motor of the regenerative braking system of the i-th wheel at time t is in a critical failure state, while the actuator motor of the electronic mechanical braking system is in a normal working state; when and When , it indicates that the electronic mechanical brake system executive motor and the regenerative brake system hub motor of the i-th wheel at time t are both in a critical failure state;

[0079] The safety assurance module executes corresponding safety assurance measures according to the value of the safety state judgment coefficient of the composite wire control brake system actuator; the safety assurance measures include first-level safety assurance measures, second-level safety assurance measures, third-level safety assurance measures, fourth-level safety assurance measures and fifth-level safety assurance measures.

[0080] The calculation formula of the electrical performance index of the electromechanical brake system actuator is:

[0081]

[0082] In the formula, x Eec It is the electrical performance index of the actuator of the electromechanical brake system; E Current of the motor that executes the electromechanical brake system; V E Input voltage to the motor for the electromechanical brake system; τ E The delay time for the motor to run for the electromechanical brake system; E is the electromagnetic interference level of the electric motor of the electronic mechanical brake system; α1, α2, α3 and α4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0083] The calculation formula of the mechanical structure and component status index of the electromechanical brake system actuator is:

[0084]

[0085] In the formula, x Emc It is the mechanical structure and component status indicator of the electromechanical brake system actuator; W Ebea The bearing wear of the motor for the electromechanical brake system; L Eg Fatigue life of the transmission gear tooth surface of the motor for the electronic mechanical brake system; A vib Vibration amplitude of the motor for the electromechanical brake system; E nis the noise level of the motor executing the electronic mechanical brake system; β1, β2, β3 and β4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0086] The calculation formula for the thermal management and heat dissipation capability index of the electromechanical brake system actuator is:

[0087]

[0088] In the formula, x Ett It is the thermal management and heat dissipation capability index of the electronic mechanical brake system actuator; T Er The rotor temperature of the motor that executes the electromechanical brake system; T Es The stator temperature of the motor that performs the electromechanical brake system; T Eh The housing temperature of the motor that performs the electromechanical brake system; η Ec is the cooling system efficiency of the electronic mechanical brake system actuator; ε1, ε2 and ε3 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0089] The calculation formula of the external environment index of the electronic mechanical brake system actuator is:

[0090]

[0091] In the formula, x Ee It is the external environment index of the electronic mechanical brake system actuator; T Ee The ambient temperature of the motor of the electronic mechanical brake system; H Ee The humidity of the environment where the motor of the electronic mechanical brake system is located; D Ee The dust concentration in the environment where the motor of the electronic mechanical brake system is located; C Ec Metal corrosion rates of winding wires in motors that perform electromechanical brake systems; and is the weight coefficient, and its specific value is determined through simulation and experiments.

[0092] The calculation formula of the mechanical performance index of the regenerative braking system actuator is:

[0093]

[0094] Where x Im It is the mechanical performance index of the regenerative braking system actuator; t Ires is the response time of the hub motor; A Ivib is the vibration amplitude of the hub motor; I n is the noise level of the hub motor; W Ibis the wear amount of the hub motor bearing; ω1, ω2, ω3 and ω4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0095] The calculation formula of the electrical performance index of the regenerative braking system actuator is:

[0096]

[0097] In the formula, x Ie It is the electrical performance index of the regenerative braking system actuator; I Bcm is the maximum operating current of the hub motor; V Bm is the maximum operating voltage of the hub motor; R Ins is the insulation resistance of the hub motor winding; ρ1, ρ2, ρ3 and ρ4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0098] The calculation formula of the thermal performance index of the regenerative braking system actuator is:

[0099]

[0100] In the formula, x It It is the thermal performance index of the regenerative braking system actuator; Q Ia is the heat accumulation of the hub motor; T Is is the shell temperature of the hub motor; T Ic is the coolant temperature of the hub motor; v Ic is the coolant flow rate of the hub motor; ζ1, ζ2, ζ3 and ζ4 are weight coefficients, and their specific values ​​are determined through simulation and experiments;

[0101] The calculation formula of the braking efficiency index of the regenerative braking system actuator is:

[0102]

[0103] In the formula, x Ire It is the braking efficiency index of the regenerative braking system actuator; P Ire is the regenerative braking power of the hub motor; I Ire is the regenerative braking current of the hub motor; T Ire is the regenerative braking torque of the hub motor; η Ire is the regenerative braking energy recovery rate of the hub motor; λ1, λ2, λ3 and λ4 are weight coefficients, and their specific values ​​are determined through simulation and experiments.

[0104] The execution condition of the first-level safety guarantee measure is: the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the four wheels at the current moment are all equal to 0; the first-level safety guarantee measure is specifically: the vehicle completes the braking process normally, and no intervention is required on the vehicle;

[0105] The execution condition of the second-level safety guarantee measure is: at the current moment, the value of the safety state judgment coefficient of the composite wire control brake system actuator of only one wheel is equal to 1, while the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the other three wheels are all equal to 0; the second-level safety guarantee measure is specifically: using the failure prediction factor of the electronic mechanical brake system actuator to calculate the first advance opening time for regenerative braking compensation of the wheel corresponding to the critical failure state of the electronic mechanical brake system actuator motor; making the regenerative braking torque of the wheel corresponding to the critical failure state of the electronic mechanical brake system actuator motor equal to the mechanical braking torque generated when the electronic mechanical brake system actuator motor is in the critical failure state; if the regenerative braking torque of the wheel hub motor corresponding to the critical failure state of the electronic mechanical brake system actuator motor cannot meet the mechanical braking torque demand, then the insufficient mechanical braking torque is evenly distributed to the two wheels on the same axle whose values ​​of the safety state judgment coefficients of the composite wire control brake system actuator are both equal to 0, and compensated by the electronic mechanical brake system;

[0106] The calculation formula of the first advance opening time is:

[0107] t1=y E ·(t Iest +t Imdr +t Ier + Imr +t Ifa )

[0108] Where, t1 is the first advance opening time; y E is the failure prediction factor of the electronic mechanical brake system actuator; t Icst is the transmission time of the wheel hub motor control signal; t Imdr is the response time of the wheel hub motor driver; t Ier is the electromagnetic response time of the hub motor; t Imr is the mechanical response time of the hub motor; t Ifa Adjust timing for in-wheel motor control feedback and closed loop.

[0109] The execution condition of the third-level safety guarantee measure is: at the current moment, the value of the safety state judgment coefficient of the composite wire control brake system actuator of only one wheel is equal to 2, and the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the other three wheels are all equal to 0; the third-level safety guarantee measure is specifically: using the regenerative braking system actuator failure estimation factor to calculate the second advance start time of mechanical braking compensation for the wheel corresponding to the critical failure state of the regenerative braking system hub motor; making the mechanical braking torque of the wheel corresponding to the critical failure state of the regenerative braking system hub motor equal to the regenerative braking torque generated when the regenerative braking system hub motor is in the critical failure state;

[0110] The calculation formula of the second advance opening time is:

[0111] t2=y I ·(t Esp +t Ecc +t Ead +t Emr +t Efa )

[0112] Where, t2 is the second advance opening time; y I is the failure prediction factor of the regenerative braking system actuator; t Esp is the signal processing time of the electronic mechanical brake system; t Ecc Calculation time for the electronic mechanical brake system controller; t Ead The motor driving time for the electromechanical brake system; t Emr The mechanical response time of the motor for the electromechanical brake system; t Efa Perform motor control feedback and closed-loop adjustment timing for electromechanical brake systems.

[0113] The execution condition of the fourth-level safety guarantee measure is: at the current moment, the value of the safety state judgment coefficient of the composite wire control brake system actuator of only one wheel is equal to 3, while the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the other three wheels are all equal to 0; the fourth-level safety guarantee measure is specifically: using the failure prediction factor of the electronic mechanical braking system actuator and the failure prediction factor of the regenerative braking system actuator to calculate the third advance start time of the regenerative braking compensation of the same-side wheel corresponding to the wheel where the electronic mechanical braking system execution motor and the regenerative braking system hub motor are both in a critical failure state; making the regenerative braking torque of the same-side wheel equal to the total braking torque of the wheel corresponding to the electronic mechanical braking system execution motor and the regenerative braking system hub motor are both in a critical failure state; if the regenerative braking torque of the same-side wheel cannot meet the total braking torque requirement, the insufficient total braking torque is compensated by the electronic mechanical braking system of the same-side wheel;

[0114] The calculation formula of the third advance opening time is:

[0115] t3=max(y E ,y I )·(t Icst + Imdr +t Ier +t Imr +t Ifa )

[0116] Where, t3 is the third advance opening time; y E is the failure prediction factor of the electronic mechanical brake system actuator; I is the failure prediction factor of the regenerative braking system actuator; t Icst is the transmission time of the wheel hub motor control signal; t Imdr is the response time of the wheel hub motor driver; t Ier is the electromagnetic response time of the hub motor; t Imr is the mechanical response time of the hub motor; t Ifa Adjust timing for wheel hub motor control feedback and closed loop;

[0117] The execution condition of the fifth-level safety protection measures is: at the current moment, the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of two or more wheels are not equal to 0; the fifth-level safety protection measures are specifically: adopting redundant mechanical braking or redundant hydraulic braking to achieve safe stopping of the vehicle.

Claims

1. An intelligent failure prediction and safety assurance system for actuators of a composite braking system, characterized in that: It includes a composite wire-controlled brake system actuator state information acquisition module, an electronic mechanical brake system actuator state evaluation module, a regenerative brake system actuator state evaluation module, a composite wire-controlled brake system actuator safety state judgment module and a safety assurance module; The composite brake-by-wire system actuator state information acquisition module is used to obtain state information of the electromechanical brake system actuator and the regenerative brake system actuator, and provide the electromechanical brake system actuator state evaluation module and the regenerative brake system actuator state evaluation module with information sources required for state evaluation; The electronic mechanical brake system actuator state assessment module uses a long short-term memory network algorithm to calculate the failure prediction factor of the electronic mechanical brake system actuator according to the electrical performance index of the electronic mechanical brake system actuator, the mechanical structure and component state index of the electronic mechanical brake system actuator, the thermal management and heat dissipation capacity index of the electronic mechanical brake system actuator, and the external environment index of the electronic mechanical brake system actuator; The calculation formula of the failure prediction factor of the electronic mechanical brake system actuator is: In the formula, is the state input vector of the electronic mechanical brake system actuator of the i-th wheel at time t, i=1, 2, 3, 4 represent the left front wheel, right front wheel, left rear wheel and right rear wheel respectively; is the normalized state input vector of the electromechanical brake system actuator of the i-th wheel at time t; is the electrical performance index of the electromechanical brake system actuator of the i-th wheel at time t; is the mechanical structure and component status index of the electronic mechanical brake system actuator of the i-th wheel at time t; is the thermal management and heat dissipation capability index of the electronic mechanical brake system actuator of the i-th wheel at the moment; is the external environment index of the electronic mechanical brake system actuator of the i-th wheel at time t; is the hidden state of the failure prediction of the actuator of the electronic mechanical brake system of the i-th wheel at time t-1; is the memory unit state of the failure prediction of the actuator of the electromechanical brake system of the i-th wheel at time t; is the memory unit state of the failure prediction of the actuator of the electronic mechanical brake system of the i-th wheel at time t-1; and is the weight matrix for predicting the failure of the actuator of the electromechanical brake system of the i-th wheel; and is the bias term for failure prediction of the electronic mechanical brake system actuator of the i-th wheel; σ is the sigmoid activation function; tanh is the hyperbolic tangent activation function; is the failure prediction factor of the electronic mechanical brake system actuator of the i-th wheel at time t, and its value range is between 0 and 1; The regenerative braking system actuator state evaluation module calculates the regenerative braking system actuator failure prediction factor using a long short-term memory network algorithm based on the mechanical performance index of the regenerative braking system actuator, the electrical performance index of the regenerative braking system actuator, the thermal performance index of the regenerative braking system actuator, and the braking efficiency index of the regenerative braking system actuator; The calculation formula of the regenerative braking system actuator failure prediction factor is: In the formula, is the state input vector of the regenerative braking system actuator of the i-th wheel at time t, i=1, 2, 3, 4 represent the left front wheel, right front wheel, left rear wheel and right rear wheel respectively; is the normalized state input vector of the regenerative braking system actuator of the i-th wheel at time t; is the mechanical performance index of the regenerative braking system actuator of the i-th wheel at time t; is the electrical performance index of the regenerative braking system actuator of the i-th wheel at time t; is the thermal performance index of the regenerative braking system actuator of the i-th wheel at time t; is the braking efficiency index of the regenerative braking system actuator of the i-th wheel at time t; is the hidden state of the regenerative braking system actuator failure prediction of the i-th wheel at time t-1; is the memory unit state of the regenerative braking system actuator failure prediction of the i-th wheel at time t; is the memory unit state of the regenerative braking system actuator failure prediction of the i-th wheel at time t-1; and is the weight matrix for predicting the failure of the regenerative braking system actuator of the i-th wheel; and is the bias term for failure prediction of the regenerative braking system actuator of the i-th wheel; σ is the sigmoid activation function; tanh is the hyperbolic tangent activation function; is the failure prediction factor of the regenerative braking system actuator of the i-th wheel at time t, and its value range is between 0 and 1; The composite brake-by-wire system actuator safety state judgment module determines the composite brake-by-wire system actuator safety state judgment coefficient according to the electromechanical brake system actuator failure prediction factor and the regenerative brake system actuator failure prediction factor; The safety state judgment coefficient of the composite brake-by-wire system actuator is used to judge the safety state of the composite brake-by-wire system actuator; The calculation formula of the safety state judgment coefficient of the composite brake-by-wire system actuator is: In the formula, is the failure prediction factor of the electronic mechanical brake system actuator of the i-th wheel at time t, where i=1, 2, 3, 4 represent the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively; is the failure prediction factor of the regenerative braking system actuator of the i-th wheel at time t; is the safety state judgment coefficient of the composite brake-by-wire system actuator of the i-th wheel at time t; the specific meaning of the calculation formula of the safety state judgment coefficient of the composite brake-by-wire system actuator is: and When , it indicates that the electronic mechanical brake system executive motor and the regenerative brake system hub motor of the i-th wheel at time t are in normal working condition; when and When , it indicates that the actuator motor of the electronic mechanical brake system of the i-th wheel at time t is in a critical failure state, while the wheel hub motor of the regenerative brake system is in a normal working state; when and When , it indicates that the wheel hub motor of the regenerative braking system of the i-th wheel is in a critical failure state, while the actuator motor of the electronic mechanical braking system is in a normal working state; when and When , it indicates that the electronic mechanical brake system executive motor and the regenerative brake system hub motor of the i-th wheel at time i are both in a critical failure state; The safety assurance module executes corresponding safety assurance measures according to the value of the safety state judgment coefficient of the composite wire control brake system actuator; the safety assurance measures include first-level safety assurance measures, second-level safety assurance measures, third-level safety assurance measures, fourth-level safety assurance measures and fifth-level safety assurance measures.

2. The intelligent failure prediction and safety assurance system for actuators of a composite brake system according to claim 1, characterized in that: The calculation formula of the electrical performance index of the electromechanical brake system actuator is: In the formula, x Eec It is the electrical performance index of the actuator of the electromechanical brake system; E Current of the motor that executes the electromechanical brake system; V E Input voltage to the motor for the electromechanical brake system; τ E The delay time for the motor to run for the electromechanical brake system; E is the electromagnetic interference level of the electric motor of the electronic mechanical brake system; α1, α2, α3 and α4 are weight coefficients, and their specific values ​​are determined through simulation and experiments; The calculation formula of the mechanical structure and component status index of the electromechanical brake system actuator is: In the formula, x Emc It is the mechanical structure and component status indicator of the electromechanical brake system actuator; W Ebea The bearing wear of the motor for the electromechanical brake system; L Eg Fatigue life of the transmission gear tooth surface of the motor for the electronic mechanical brake system; A vib Vibration amplitude of the motor for the electromechanical brake system; E n is the noise level of the motor executing the electronic mechanical brake system; β1, β2, β3 and β4 are weight coefficients, and their specific values ​​are determined through simulation and experiments; The calculation formula for the thermal management and heat dissipation capability index of the electromechanical brake system actuator is: In the formula, x Ett It is the thermal management and heat dissipation capability index of the electronic mechanical brake system actuator; T Er The rotor temperature of the motor that executes the electromechanical brake system; T Es The stator temperature of the motor that performs the electromechanical brake system; T Eh The housing temperature of the motor actuating the electromechanical brake system; η Ec is the cooling system efficiency of the electronic mechanical brake system actuator; ε1, ε2 and ε3 are weight coefficients, and their specific values ​​are determined through simulation and experiments; The calculation formula of the external environment index of the electronic mechanical brake system actuator is: In the formula, x Ee It is the external environment index of the electronic mechanical brake system actuator; T Ee The ambient temperature of the motor of the electronic mechanical brake system; H Ee The humidity of the environment where the motor of the electronic mechanical brake system is located; D Ee The dust concentration in the environment where the motor of the electronic mechanical brake system is located; C Ec Metal corrosion rates of winding wires in motors that perform electromechanical brake systems; and is the weight coefficient, and its specific value is determined through simulation and experiments.

3. The intelligent failure prediction and safety assurance system for actuators of a composite brake system according to claim 1, characterized in that: The calculation formula of the mechanical performance index of the regenerative braking system actuator is: Where x Im It is the mechanical performance index of the regenerative braking system actuator; t Ires is the response time of the hub motor; A Ivib is the vibration amplitude of the hub motor; I n is the noise level of the hub motor; W Ib is the wear amount of the hub motor bearing; ω1, ω2, ω3 and ω4 are weight coefficients, and their specific values ​​are determined through simulation and experiments; The calculation formula of the electrical performance index of the regenerative braking system actuator is: In the formula, x Ie It is the electrical performance index of the regenerative braking system actuator; I Bcm is the maximum operating current of the hub motor; V Bm is the maximum operating voltage of the hub motor; R Ins is the insulation resistance of the hub motor winding; ρ1, ρ2, ρ3 and ρ4 are weight coefficients, and their specific values ​​are determined through simulation and experiments; The calculation formula of the thermal performance index of the regenerative braking system actuator is: In the formula, x It It is the thermal performance index of the regenerative braking system actuator; Q Ia is the heat accumulation of the hub motor; T Is is the shell temperature of the hub motor; T Ic is the coolant temperature of the hub motor; v Ic is the coolant flow rate of the hub motor; ζ1, ζ2, ζ3 and ζ4 are weight coefficients, and their specific values ​​are determined through simulation and experiments; The calculation formula of the braking efficiency index of the regenerative braking system actuator is: In the formula, x Ire It is the braking efficiency index of the regenerative braking system actuator; P Ire is the regenerative braking power of the hub motor; I Ire is the regenerative braking current of the hub motor; T Ire is the regenerative braking torque of the wheel hub motor; η Ire is the regenerative braking energy recovery rate of the hub motor; λ1, λ2, λ3 and λ4 are weight coefficients, and their specific values ​​are determined through simulation and experiments.

4. The intelligent failure prediction and safety assurance system for actuators of a composite brake system according to claim 1, characterized in that: The execution condition of the first-level safety guarantee measure is: the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the four wheels at the current moment are all equal to 0; the first-level safety guarantee measure is specifically: the vehicle completes the braking process normally, and no intervention is required on the vehicle; The execution condition of the second-level safety guarantee measure is: at the current moment, the value of the safety state judgment coefficient of the composite wire control brake system actuator of only one wheel is equal to 1, and the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the other three wheels are all equal to 0; the second-level safety guarantee measure is specifically: using the failure prediction factor of the electronic mechanical brake system actuator to calculate the first advance start time of the regenerative braking compensation of the wheel corresponding to the critical failure state of the electronic mechanical brake system actuator motor; The regenerative braking torque of the wheel corresponding to the critical failure state of the electronic mechanical brake system's actuator motor is set equal to the mechanical braking torque generated when the electronic mechanical brake system's actuator motor is in the critical failure state; if the regenerative braking torque of the wheel hub motor corresponding to the critical failure state of the electronic mechanical brake system's actuator motor cannot meet the mechanical braking torque requirement, the insufficient mechanical braking torque is evenly distributed to the two wheels on the same axle whose values ​​of the safety state judgment coefficient of the composite wire control brake system actuator are both equal to 0, and the electronic mechanical brake system is used to compensate for it; The calculation formula of the first advance opening time is: t1=y E ·(t Icst +t Imdr +t Ier +t Imr +t Ifa ) Where, t1 is the first advance opening time; y E is the failure prediction factor of the electromechanical brake system actuator; t Icst is the transmission time of the wheel hub motor control signal; t Imdr is the response time of the wheel hub motor driver; t Ier is the electromagnetic response time of the hub motor; t Imr is the mechanical response time of the hub motor; t Ifa Adjust timing for in-wheel motor control feedback and closed loop.

5. The intelligent failure prediction and safety assurance system for actuators of a composite brake system according to claim 1, characterized in that: The execution condition of the third-level safety guarantee measure is: at the current moment, the value of the safety state judgment coefficient of the composite wire control brake system actuator of only one wheel is equal to 2, and the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the other three wheels are all equal to 0; the third-level safety guarantee measure is specifically: using the regenerative braking system actuator failure estimation factor to calculate the second advance start time of mechanical braking compensation for the wheel corresponding to the critical failure state of the regenerative braking system hub motor; making the mechanical braking torque of the wheel corresponding to the critical failure state of the regenerative braking system hub motor equal to the regenerative braking torque generated when the regenerative braking system hub motor is in the critical failure state; The calculation formula of the second advance opening time is: t2=y I ·(t Esp +t Ecc +t Ead +t Emr +t Efa ) Where, t2 is the second advance opening time; y I is the failure prediction factor of the regenerative braking system actuator; t Esp It is the signal processing time of the electronic mechanical brake system; t Ecc Calculates time for the electromechanical brake system controller; t Ead The motor driving time for the electromechanical brake system; t Emr Implementing motor-mechanical response time for an electromechanical brake system; t Efa Perform motor control feedback and closed-loop adjustment timing for electromechanical brake systems.

6. The intelligent failure prediction and safety assurance system for actuators of a composite brake system according to claim 1, characterized in that: The execution condition of the fourth-level safety guarantee measure is: at the current moment, the value of the safety state judgment coefficient of the composite wire control brake system actuator of only one wheel is equal to 3, and the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of the other three wheels are all equal to 0; the fourth-level safety guarantee measure is specifically: using the failure prediction factor of the electronic mechanical braking system actuator and the failure prediction factor of the regenerative braking system actuator to calculate the third advance start time of the regenerative braking compensation for the same side wheel corresponding to the wheel where both the electronic mechanical braking system actuator motor and the regenerative braking system hub motor are in a critical failure state; The regenerative braking torque of the wheel on the same side is set equal to the total braking torque of the wheel corresponding to the critical failure state of the electronic mechanical braking system executive motor and the regenerative braking system hub motor; if the regenerative braking torque of the wheel on the same side cannot meet the total braking torque requirement, the insufficient total braking torque is compensated by the electronic mechanical braking system of the wheel on the same side; The calculation formula of the third advance opening time is: t3=max(y E ,y I )·(t Icst +t Imdr +t Ier +t Imr +t Ifa ) Where, t3 is the third advance opening time; y E is the failure prediction factor of the electronic mechanical brake system actuator; I is the failure prediction factor of the regenerative braking system actuator; t Icst is the transmission time of the wheel hub motor control signal; t Imdr is the response time of the wheel hub motor driver; t Ier is the electromagnetic response time of the hub motor; t Imr is the mechanical response time of the hub motor; t Ifa Adjust timing for wheel hub motor control feedback and closed loop; The execution condition of the fifth-level safety protection measures is: at the current moment, the values ​​of the safety state judgment coefficients of the composite wire control brake system actuators of two or more wheels are not equal to 0; the fifth-level safety protection measures are specifically: adopting redundant mechanical braking or redundant hydraulic braking to achieve safe stopping of the vehicle.

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