Electronic mechanical brake calipers for braking hub motor and working method of electronic mechanical brake calipers

Abstract

The invention discloses an electronic mechanical brake caliper for braking a hub motor and a working method thereof, and belongs to the field of brake calipers, the electronic mechanical brake caliper comprises an EMB motor, a speed reducer connected with a rotor shaft of the EMB motor, and a caliper body connected with the output end of the speed reducer, the system further comprises a PCB integrated with a brake controller and a double-closed-loop control system and a full-life-cycle state sensing module, the full-life-cycle state sensing module is electrically connected with the input end of the brake controller, the output end of the brake controller is electrically connected with the double-closed-loop control system, and the double-closed-loop control system is electrically connected with the hub motor and the EMB motor. By the adoption of the electronic mechanical brake caliper for hub motor braking and the working method of the electronic mechanical brake caliper, the braking safety, the energy recovery efficiency, the response precision and the service life of parts are cooperatively improved, and the comprehensive requirement for hub motor braking is perfectly met.

Description

An electromechanical brake caliper for hub motor braking and its working method Technical Field

[0001] This invention relates to the field of brake caliper technology, and in particular to an electromechanical brake caliper for hub motor braking and its working method. Background Technology

[0002] With the rapid development of the new energy vehicle industry, hub motors have become one of the core technologies of the next generation of new energy vehicles due to their advantages of distributed drive, short transmission chain and high space utilization. The braking system that works with hub motors mainly adopts the following technologies: 1. Traditional hydraulic braking system: (1) Significant response delay, the brake gap elimination time is usually 150-200ms, which is difficult to meet the rapid response requirements of high-speed emergency braking; (2) Large unsprung mass, the weight of cast iron calipers is generally ≥6kg, which increases the unsprung mass burden of hub motors; (3) Poor energy recovery coordination, unable to dynamically match regenerative braking, and almost no energy recovery capability; (4) Lack of state perception capability, unable to monitor key states such as brake disc wear and cracks, which can easily cause safety hazards due to brake disc failure; (5) High maintenance cost, the hydraulic system has the risk of leakage, and the brake fluid needs to be replaced regularly.

[0003] 2. Ordinary electromechanical brake (EMB) calipers: (1) Insufficient lightweighting, mostly made of aluminum alloy, with a weight of ≥4.5kg, which does not fully meet the lightweighting requirements of hub motors; (2) Lack of state perception, unable to detect brake disc runout, thickness change and crack depth in real time, and the braking force distribution adopts a fixed ratio without considering brake disc state decay; (3) Weak anti-disturbance capability, mostly using traditional PID control, which has poor suppression effect on nonlinear disturbances such as friction coefficient fluctuation and load change during the braking process, and the clamping force error is generally ≥5%.

[0004] In summary, existing braking technologies cannot simultaneously meet the comprehensive requirements of hub motors for lightweight, high precision, high safety, high recyclability, and long lifespan. Summary of the Invention

[0005] The purpose of this invention is to provide an electromechanical brake caliper for hub motor braking and its working method, thereby solving the above-mentioned technical problems.

[0006] To achieve the above objectives, this invention provides an electromechanical brake caliper for hub motor braking, comprising an EMB motor, a reducer connected to the rotor shaft of the EMB motor, and a caliper body connected to the output end of the reducer. The invention also includes a PCB board integrating a brake controller and a dual closed-loop control system, and a full lifecycle status sensing module. The full lifecycle status sensing module is electrically connected to the input end of the brake controller, and the output end of the brake controller is electrically connected to the dual closed-loop control system. The dual closed-loop control system is electrically connected to the hub motor and the EMB motor. The full lifecycle status sensing module is used to combine the ABS wheel speed signal with the caliper... The system uses tension, motor torque, wheel speed, and vibration signals to achieve non-contact detection of brake disc runout, wear, and cracks, and transmits the detection results to the brake controller. The brake controller generates corresponding braking force adjustment commands based on the real-time detection results of the full life cycle state perception module and the vehicle's current braking needs, and outputs them to the dual closed-loop control system. The dual closed-loop control system, based on the commands from the brake controller and the regenerative braking torque of the hub motor, dynamically compensates for the mechanical braking torque through feedforward second-order linear active disturbance rejection control and a braking force extended state observer, ultimately controlling the actions of the hub motor and EMB motor to achieve braking.

[0007] A method for operating an electromechanical brake caliper for hub motor braking includes the following steps: S1. Initiating full lifecycle state perception, synchronously collecting ABS wheel speed, clamping force, motor torque, wheel speed, and vibration signals; extracting brake disc runout, thickness change, and crack depth feature parameters based on a signal feature fusion algorithm; generating a brake disc state detection report after data standardization processing and transmitting it to the brake controller; S2. Receiving the brake disc state detection report, the brake controller, combined with the vehicle's current braking demand signal, analyzes the total braking force demand and allocation ratio based on a preset functional demand weight model, generating a braking force adjustment command including regenerative braking torque target values ​​and mechanical braking torque target values, and outputting it to a dual closed-loop control system; S3. Receiving the braking force adjustment command, the dual closed-loop control system collects the real-time regenerative braking torque of the hub motor, calculates the mechanical braking torque compensation difference based on the torque balance principle, and obtains the target output torque of the EMB motor; S4. Initiating the feedforward second-order linear active disturbance rejection control algorithm of the dual closed-loop control system. By combining the braking force extended state observer to monitor load disturbances during braking in real time, the EMB motor control parameters are dynamically corrected, driving the EMB motor to output the target torque. After being reduced and amplified by the reducer, the torque is transmitted to the ball screw of the caliper body. S5: The ball screw converts the rotational torque into linear motion, pushing the screw nut and piston to move sequentially, causing the friction pads to clamp the brake disc and generate mechanical braking force. At the same time, the dual closed-loop control system collects clamping force feedback signals and brake disc status feedback signals in real time, corrects the torque, and forms a closed-loop adjustment of braking force. S6: Deployed IoT sensors continuously collect EMB motor operating parameters, reducer transmission efficiency, caliper clamping force stability, and brake disc status change data to build a full life cycle operation database. S7: Based on the full life cycle operation database, a parameter adjustment model is trained. The parameter adjustment model outputs optimized reducer transmission ratio parameters, EMB motor control gain, and braking force extended state observer compensation coefficients, dynamically updating the modular unit parameter library to achieve full life cycle adaptive optimization of braking performance.

[0008] Therefore, the present invention employs the above-mentioned electromechanical brake caliper for hub motor braking and its working method, which has the following beneficial effects: 1. Significantly improved braking safety: Real-time monitoring of brake disc runout, thickness change, and crack depth, dynamic adjustment of safety margin, and embedded ABS / ESP control logic effectively reduce the risk of brake failure; 2. Optimized energy recovery efficiency: Based on a dynamic weight model, the ratio of regeneration to mechanical braking is allocated, and adaptive adjustment is made in combination with working conditions and brake disc status to maximize the recovery of braking energy; 3. Balance of lightweight and high strength: The carbon fiber SMC caliper is 22%-42% lighter than traditional metal calipers, while meeting the mechanical requirements of equivalent stress ≤350MPa and deformation ≤0.02mm, reducing unsprung mass; 4. Strong braking accuracy and disturbance rejection: Feedforward second-order linear active disturbance rejection control + braking force extended state observer, real-time compensation for nonlinear disturbances, clamping force error ≤2%, which is better than traditional control schemes; 5. Stable performance throughout the entire life cycle: Based on a random forest model, the control parameters are optimized to extend the life of brake disc and caliper components, maintaining consistent braking performance over a long period of time.

[0009] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0010] Figure 1 is a perspective view of an electromechanical brake caliper for hub motor braking according to the present invention; Figure 2 is an assembly diagram of an electromechanical brake caliper for hub motor braking according to the present invention; Figure 3 is a flowchart of the working method of an electromechanical brake caliper for hub motor braking according to the present invention.

[0011] The attached diagram shows: 1. EMB motor; 2. Reducer; 3. Cylinder; 4. Friction plate; 5. Brake disc. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0013] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device.

[0014] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0015] As shown in Figures 1 and 2, an electromechanical brake caliper for hub motor braking includes an EMB motor 1, a reducer 2 connected to the rotor shaft of the EMB motor 1, and a caliper body connected to the output end of the reducer 2. The invention also includes a PCB board integrating a brake controller and a dual closed-loop control system, as well as a full lifecycle status sensing module. The full lifecycle status sensing module is electrically connected to the input end of the brake controller, and the output end of the brake controller is electrically connected to the dual closed-loop control system. The dual closed-loop control system is electrically connected to the hub motor and the EMB motor. The full lifecycle status sensing module is used to clamp the caliper in conjunction with the ABS wheel speed signal. The system uses force, motor torque, wheel speed, and vibration signals to achieve non-contact detection of brake disc 5-speed runout, wear, and cracks, and transmits the detection results to the brake controller. The brake controller generates corresponding braking force adjustment commands based on the real-time detection results of the full life cycle state perception module and the vehicle's current braking needs, and outputs them to the dual closed-loop control system. The dual closed-loop control system, based on the commands from the brake controller and the regenerative braking torque of the hub motor, dynamically compensates for the mechanical braking torque through feedforward second-order linear active disturbance rejection control and a braking force extended state observer, ultimately controlling the actions of the hub motor and EMB motor to achieve braking.

[0016] It should be noted that the above perception is achieved using the vehicle's built-in sensors, without the need to add sensing technology. Furthermore, the above electronic components are all mature products on the market. This embodiment only requires purchasing them and connecting them according to the instruction manual, without making any modifications. Therefore, their circuit connection structure and principle will not be described in detail here.

[0017] The caliper body is made of carbon fiber sheet molding compound through compression molding. The fiber content of the caliper body is 53wt%±2wt%, the fiber length is 25.4mm, and the porosity after molding is ≤2%. The compression molding process parameters meet the following requirements: mold temperature 140℃±5℃, molding pressure 8MPa±0.5MPa, curing time 3min / mm±0.2min / mm, followed by aging treatment at 325℃×240min. The equivalent stress of the caliper body is ≤350MPa, and the deformation is ≤0.02mm. The EMB motor 1 transmits torque to the ball screw of the caliper body through the reducer 2. The torque is converted into clamping force of the caliper body through the screw nut, piston, and friction plate 4, and the transmission ratio is... The following requirements must be met: ;in, ; In the formula, and These represent the minimum transmission ratio and the maximum transmission ratio, respectively. Indicates the target clamping thrust; Indicates the lead of the ball screw; This indicates the rated torque of the EMB motor; Indicates the transmission efficiency of the reducer; Indicates the efficiency of the ball screw drive; Indicates the maximum speed of the EMB motor; Indicates the maximum permissible linear speed of the ball screw; Indicates the unit conversion factor; the diameter of the ball screw. The following constraints must be met: In the formula, Indicates the maximum clamping force; This represents the allowable stress of the ball screw material; the lead and response time of the ball screw must satisfy the following conditions: In the formula, Indicates the braking clearance elimination time; This indicates the initial gap between the friction pads of the caliper body and the brake disc 5; This indicates the rated angular velocity of the EMB motor; Indicates the maximum permissible brake clearance elimination time; caliper body cylinder wall thickness 3 The following conditions must be met: In the formula, This indicates the bending moment borne by the cylinder of the caliper body during braking; This indicates the outer diameter of the cylinder section of the caliper body; This indicates the allowable stress of the carbon fiber sheet molding compound.

[0018] A method for operating an electromechanical brake caliper for hub motor braking includes the following steps: S1. Initiating full lifecycle state perception, synchronously collecting ABS wheel speed, clamping force, motor torque, wheel speed, and vibration signals; extracting brake disc runout, thickness change, and crack depth feature parameters based on a signal feature fusion algorithm; generating a brake disc state detection report after data standardization processing and transmitting it to the brake controller; S2. Receiving the brake disc state detection report, the brake controller, combined with the vehicle's current braking demand signal, analyzes the total braking force demand and allocation ratio based on a preset functional demand weight model, generating a braking force adjustment command including regenerative braking torque target values ​​and mechanical braking torque target values, and outputting it to a dual closed-loop control system; S3. Receiving the braking force adjustment command, the dual closed-loop control system collects the real-time regenerative braking torque of the hub motor, calculates the mechanical braking torque compensation difference based on the torque balance principle, and obtains the target output torque of the EMB motor; S4. Initiating the feedforward second-order linear active disturbance rejection control algorithm of the dual closed-loop control system. By combining the braking force extended state observer to monitor load disturbances during braking in real time, the EMB motor control parameters are dynamically corrected, driving the EMB motor to output the target torque. After being reduced and amplified by the reducer, the torque is transmitted to the ball screw of the caliper body. S5: The ball screw converts the rotational torque into linear motion, pushing the screw nut and piston to move sequentially, causing the friction pads to clamp the brake disc and generate mechanical braking force. At the same time, the dual closed-loop control system collects clamping force feedback signals and brake disc status feedback signals in real time, corrects the torque, and forms a closed-loop adjustment of braking force. S6: Deployed IoT sensors continuously collect EMB motor operating parameters, reducer transmission efficiency, caliper clamping force stability, and brake disc status change data to build a full life cycle operation database. S7: Based on the full life cycle operation database, a parameter adjustment model is trained. The parameter adjustment model outputs optimized reducer transmission ratio parameters, EMB motor control gain, and braking force extended state observer compensation coefficients, dynamically updating the modular unit parameter library to achieve full life cycle adaptive optimization of braking performance.

[0019] Step S1 specifically includes the following steps: S11, synchronous acquisition via CAN bus S11: Clamping force, motor torque, wheel speed, and vibration signals; S12: Use a 5th-order Butterworth high-pass filter to filter out low-frequency interference in the signals acquired in step S11; S13: Extract brake disc runout separately. Thickness variation and crack depth Feature parameters: ; ; In the formula, This represents the amplitude of linear velocity fluctuation, and , This indicates the frequency corresponding to the wheel speed after the wheel linear velocity signal is transformed by FFT. The frequency domain amplitude at that point, and , , This represents the frequency domain function obtained by performing a Fourier transform (FFT) on the wheel linear velocity signal. Indicates the linear velocity of the wheel. , This represents the wheel speed after noise reduction. Indicates the effective rolling radius of the wheel; This indicates the frequency corresponding to the wheel speed, and , This represents the average angular velocity of the wheel speed signal after noise reduction; This represents the average value of the torque fluctuation of the EMB motor; Indicates the transmission efficiency of the reducer; Indicates the efficiency of the ball screw drive; Indicates the stiffness of the friction plate; Indicates the effective contact area of ​​the friction pads; This indicates the coefficient of friction between the friction pads and the brake disc; Represents the peak value of the power spectral density of the vibration signal; This represents the vibration-crack depth correction factor; S14. The extracted brake disc runout is normalized using Min-Max standardization. Thickness variation and crack depth The brake disc runout is obtained by standardization. Thickness variation and crack depth S15. Generate a brake disc status detection report and transmit it to the brake controller.

[0020] Step S2 specifically includes the following steps: S21, using the brake pedal displacement and speed to reflect the driver's braking intention, and combining vehicle speed and wheel-end load, converting it into a quantified braking intensity requirement through a calibration mapping relationship. and target deceleration : ; In the formula, and These represent the displacement coefficient and the velocity coefficient, respectively. Indicates the displacement of the brake pedal; Indicates the speed of the brake pedal; Indicates braking intensity; S22: Dynamically allocate weights based on preset function priorities. ; ; In the formula, , and These represent the final safety weight, energy recovery weight, and component lifespan weight, respectively. , and These represent the basic safety weight, energy recovery weight, and component lifespan weight, respectively. ; and These represent the state correction factor and the operating condition correction factor, respectively. , S23. Based on the target deceleration Calculate the total braking force and dynamically allocate the ratio of regenerative to mechanical braking based on functional weights: Total braking force requirement of the braking system : Regeneration allocation ratio : Mechanical braking distribution ratio ; Target value for regenerative braking : Mechanical braking target value : In the formula, Indicates the total mass of the vehicle; This indicates the maximum braking force of regenerative braking, and , This indicates the maximum regenerative braking torque; S24, considering the brake disc condition level, a safety margin is added, and the target braking force value after adding the safety margin is converted into a torque command for the EMB motor, which is output to the dual closed-loop control system via the CAN bus; where, the target regenerative braking torque value The expression is as follows: Target value of mechanical braking torque The expression is as follows: In the formula, Indicates a safety margin, and .

[0021] Step S3 specifically includes the following steps: S31, acquiring real-time regenerative braking torque through a torque sensor. The real-time regenerative braking torque was obtained by applying a moving average filter. S32. Based on the torque balance principle, and considering the transmission efficiency of the reducer. Calculate the mechanical braking torque compensation difference. : ;in, In the formula, Indicates regenerative torque deviation; S33, compensates for the difference in mechanical braking torque. Using the basic target torque of the EMB motor as a reference, and adding a safety margin based on the condition of the brake disc, the target output torque of the EMB motor is determined. : In the formula, This indicates the maximum output torque of the EMB motor.

[0022] Step S4 specifically includes the following steps: S41, Initialize the parameters of the feedforward second-order linear active disturbance rejection control algorithm based on the static characteristics of the EMB motor: ; ; ; ; In the formula, This indicates the bandwidth of the extended state observer; , and Both represent the extended state observer gain; Represents the feedforward coefficient; This represents the bandwidth of the feedforward second-order linear active disturbance rejection controller; This indicates the torque coefficient of the EMB motor; This represents the moment of inertia of the EMB motor. S42. Initialize the extended state observer state based on the static characteristics of the EMB motor, representing the armature resistance of the EMB motor. , , In the formula, , and All represent the state values ​​of the extended state observer; This indicates the initial value of the actual output torque of the EMB motor; Indicates the rate of change of torque; This represents the initial value of the total disturbance; S43, synchronously acquire the armature current and angular velocity of the EMB motor via the CAN bus, and calculate the actual output torque of the EMB motor using the motor dynamics model: ;in, In the formula, Indicates the EMB motor at time The actual output torque; This indicates the torque coefficient of the EMB motor; Indicates the EMB motor at time armature current; Indicates the EMB motor at time angular acceleration; and These represent the EMB motor at time [time]. and Angular velocity; S44, Treat the nonlinear disturbance during braking as a total disturbance, and incorporate feedforward coefficients. The extended state observer tracks torque output and disturbance changes in real time, and the discretized expression of the extended state observer is as follows: In the formula, , and Indicates time The actual output torque observation, torque change rate observation, and total disturbance observation; , and Indicates time The actual output torque observation, torque change rate observation, and total disturbance observation; , and express The rate of change of the observed values ​​at time points; S45. The total disturbance observation is verified based on the 3σ criterion combined with threshold constraints. The validity of the output is the total effective disturbance value. : ;in, ; In the formula, and These represent the lower and upper limits of the total disturbance threshold, respectively; This represents the mean of the total disturbance sliding window; This represents the standard deviation of the total disturbance sliding window; Indicates time The effective total disturbance value; Indicates the sliding window size; S46. Based on the feedforward second-order linear active disturbance rejection law, combined with feedforward compensation and known disturbances, the EMB motor control voltage is corrected: ;in, ; ; ; In the formula, This indicates the corrected EMB motor control voltage; This indicates the control quantity after disturbance compensation; This indicates the maximum control voltage of the EMB motor; Indicates the basic control quantity; and Both represent PID feedback gain; This indicates the torque tracking error, and ; Indicates the rate of change of error; S47, the control voltage is converted through a three-phase full-bridge inverter. It is converted into motor drive current, which drives the EMB motor to output the target torque, and then transmitted to the ball screw through the reducer.

[0023] Step S5 specifically includes the following steps: S51, the motor torque is reduced and increased by the reducer and then transmitted to the ball screw, converting the rotational motion into linear motion, which pushes the piston forward; wherein, the ball screw shaft , This indicates the actual output torque of the EMB motor; piston thrust. Piston displacement , This indicates the cumulative rotation angle of the EMB motor, and S52, the piston thrust pushes the friction pads to clamp the brake disc, generating mechanical braking force through friction. : S53, Calculate clamping force error By combining the brake disc status update, the target torque of the motor is dynamically corrected to form a closed-loop adjustment of braking force; among which, the corrected target torque The expression is as follows: ;in, In the formula, This indicates the amount of torque correction.

[0024] Step S7 specifically includes the following steps: S71, using the EMB motor operating parameters and optimization objectives from the full lifecycle operation database as input, and the optimal parameter adjustment amount as output, train a random forest model; its loss function... The expression is as follows: In the formula, , and All represent the weights of the loss function; Indicates braking response time; Indicates the maximum permissible response speed; Indicates the design life of the component; Indicates component lifespan; parameter adjustment amount , S72 represents the input feature vector; with the optimization objectives of improving response speed, reducing clamping force error, and extending component life, the current EMB motor operating status parameters are input into the random forest model to obtain the parameter adjustment amount, and the optimal value is calculated by combining the original parameters; among them, the optimal transmission ratio of the reducer is... EMB motor optimal control gain ; Optimal compensation coefficients for extended state observers: , , In the formula, Indicates the original gear ratio of the reducer; This represents the gear ratio adjustment amount output by the random forest model; and This indicates the original EMB motor control gain; and This represents the EMB motor control gain adjustment amount output by the random forest model; , and This represents the gain of the optimal extended state observer; , , This represents the compensation coefficient of the original extended state observer; , , S73 represents the adjustment amount of the extended state observer compensation coefficient output by the random forest model; S74 writes the optimal value output by S72 into the modular unit parameter library and overwrites the original parameters, and verifies the performance improvement through actual vehicle operation.

[0025] Experimental conditions: 1. Vehicle parameters: total mass 1500kg, effective wheel rolling radius 0.33m, maximum regenerative braking torque 200N.m, target deceleration range 0-8m / s² 2 2. Braking System Parameters: The caliper in this experiment is made of carbon fiber SMC material, with a fiber content of 53wt%, integrating full life cycle sensing and dual closed-loop control; Comparative Example 1 (cast iron material, hydraulic transmission, no regenerative braking coordination function, no state sensing module); Comparative Example 2 (aluminum alloy material, traditional PID control, fixed regenerative braking distribution ratio of 30%, no full life cycle sensing and optimization function); 3. Test Conditions: Urban conditions (vehicle speed 0-60km / h, frequent start-stop, brake pedal displacement 0-50mm), high-speed conditions (vehicle speed 80-120km / h, emergency braking, brake pedal speed 0.8m / s), and icy and snowy conditions (road friction coefficient 0.2, vehicle speed 40-60km / h); 4. Test Equipment: MATLAB / Simulink simulation platform, torque sensor (accuracy ±0.5%), braking response time tester (accuracy ±1ms), energy recovery efficiency analyzer.

[0026] Experimental Procedure: First, a simulation model was built: Braking system models for this experimental example and the comparative example were constructed in MATLAB / Simulink, and the parameters of each component (material properties, transmission efficiency, control algorithm, etc.) were imported. Then, test scenarios were set: Simulation parameters were set according to the initial conditions (vehicle speed, braking intent) for urban, highway, and icy / snowy conditions to ensure a consistent test environment for each scenario. Next, data acquisition was performed: Key indicators such as braking response time, regenerative braking energy, clamping force output value, brake disc wear, and caliper quality were collected synchronously. Then, repeatability testing was conducted: Each condition was repeated 10 times, random errors were eliminated, and the average value was taken as the final test result. Finally, parameter verification was performed: For the full lifecycle optimization function of this experimental example, a 100,000 km usage scenario was simulated, and component lifespan and performance degradation data were collected.

[0027] Table 1 Test Results

[0028] As shown in Table 1, this invention has the following advantages compared to Comparative Example 1 and Comparative Example 2: 1. Braking response speed: This invention eliminates hydraulic transmission delay and traditional PID regulation lag through a dual closed-loop control system and a feedforward second-order linear active disturbance rejection algorithm. The response time is shortened by 62% compared to Comparative Example 1 and by 41% compared to Comparative Example 2, enabling rapid response to the driver's braking intentions, especially suitable for high-speed emergency braking scenarios; 2. Energy recovery efficiency: Based on a dynamic weight model (dynamic adjustment of safety, energy recovery, and lifespan weights), this invention optimizes the regenerative braking ratio by combining brake disc status and operating conditions, improving efficiency by more than 45% compared to Comparative Example 2, significantly reducing the energy consumption of new energy vehicles and extending the driving range; 3. Braking accuracy: This invention tracks nonlinear disturbances (such as friction coefficient fluctuations) in real time through an extended state observer and compensates for errors through closed-loop correction, resulting in clamping force... The error is controlled within 1.5%, which is 87% and 79% lower than Comparative Examples 1 and 2, respectively, improving braking stability and comfort; 4. Lightweight and lifespan: The carbon fiber SMC material reduces the weight of the caliper by 50% compared to Comparative Example 1 and 30% compared to Comparative Example 2, reducing unsprung mass and improving handling; The full life cycle optimization model reduces component wear by adjusting parameters such as transmission ratio and control gain, extending the brake disc life by 83% compared to Comparative Example 1 and 55% compared to Comparative Example 2, with a performance degradation rate of only 5% over 100,000 kilometers, far superior to existing technologies; 5. Adaptability: In icy and snowy conditions, this invention adjusts the braking force distribution through a condition correction coefficient (ke=0.8) to avoid brake lock-up, while Comparative Examples 1 and 2, lacking dynamic adaptation capabilities, have braking distances 15%-20% longer than this invention, further verifying the condition adaptability advantage of this invention.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An electromechanical brake caliper for hub motor braking, comprising an EMB motor, a reducer connected to the rotor shaft of the EMB motor, and a caliper body connected to the output end of the reducer, characterized in that: It also includes a PCB board integrating a brake controller and a dual closed-loop control system, as well as a full lifecycle state perception module. The full lifecycle state perception module is electrically connected to the input of the brake controller, and the output of the brake controller is electrically connected to the dual closed-loop control system. The dual closed-loop control system is electrically connected to the hub motor and the EMB motor. The full lifecycle state perception module is used to achieve non-contact detection of brake disc runout, wear, and cracks by combining ABS wheel speed signals with clamping force, motor torque, wheel speed, and vibration signals, and transmits the detection results to the brake controller. The brake controller is used to generate corresponding braking force adjustment commands based on the real-time detection results of the full lifecycle state perception module and the current braking demand of the vehicle, and outputs them to the dual closed-loop control system. The dual closed-loop control system is used to dynamically compensate for mechanical braking torque based on the commands of the brake controller and the regenerative braking torque of the hub motor through feedforward second-order linear active disturbance rejection control and a braking force extended state observer, and finally control the operation of the hub motor and the EMB motor to achieve braking.

2. The electromechanical brake caliper for hub motor braking according to claim 1, characterized in that: The caliper body is made of carbon fiber sheet molding compound through compression molding. The fiber content of the caliper body is 53wt%±2wt%, the fiber length is 25.4mm, and the porosity after molding is ≤2%. The parameters of the compression molding process meet the following requirements: mold temperature 140℃±5℃, molding pressure 8MPa±0.5MPa, curing time 3min / mm±0.2min / mm, and after molding, it is aged at 325℃×240min. The equivalent stress of the caliper body is ≤350MPa, and the deformation is ≤0.02mm.

3. An electromechanical brake caliper for hub motor braking according to claim 2, characterized in that: The EMB motor transmits torque to the ball screw of the caliper body via a reducer. This torque is then converted into clamping force by the screw nut, piston, and friction plates, and the transmission ratio is [not specified]. The following requirements must be met: ;in, ； In the formula, and These represent the minimum transmission ratio and the maximum transmission ratio, respectively. Indicates the target clamping thrust; Indicates the lead of the ball screw; This indicates the rated torque of the EMB motor; Indicates the transmission efficiency of the reducer; Indicates the efficiency of the ball screw drive; Indicates the maximum speed of the EMB motor; Indicates the maximum permissible linear speed of the ball screw; Indicates the unit conversion factor; the diameter of the ball screw. The following constraints must be met: In the formula, Indicates the maximum clamping force; This represents the allowable stress of the ball screw material; the lead and response time of the ball screw must satisfy the following conditions: In the formula, Indicates the braking clearance elimination time; This indicates the initial gap between the friction pads of the caliper body and the brake disc; This indicates the rated angular velocity of the EMB motor; Indicates the maximum permissible brake clearance elimination time; cylinder wall thickness of the caliper body. The following conditions must be met: In the formula, This indicates the bending moment borne by the cylinder of the caliper body during braking; This indicates the outer diameter of the cylinder section of the caliper body; This indicates the allowable stress of the carbon fiber sheet molding compound.

4. The working method of an electromechanical brake caliper for hub motor braking as described in claim 3, characterized in that: Includes the following steps: S1. Initiate full lifecycle status perception, synchronously collect ABS wheel speed, clamping force, motor torque, wheel speed, and vibration signals. Based on signal feature fusion algorithm, extract characteristic parameters of brake disc runout, thickness change, and crack depth. After data standardization processing, generate a brake disc status detection report and transmit it to the brake controller. S2. The brake controller receives the brake disc status detection report, combines it with the vehicle's current braking demand signal, and analyzes the total braking force demand and distribution ratio based on a preset functional demand weight model. It generates a braking force adjustment command containing the target values ​​of regenerative braking torque and mechanical braking torque, and outputs it to the dual closed-loop control system. S3. The dual closed-loop control system receives the braking force adjustment command, collects the real-time regenerative braking torque of the wheel hub motor in real time, calculates the mechanical braking torque compensation difference based on the torque balance principle, and obtains the target output torque of the EMB motor. S4. The feedforward second-order linear active disturbance rejection control algorithm of the dual closed-loop control system is activated. Combined with the braking force extended state observer, the load disturbance during the braking process is monitored in real time, and the EMB motor control parameters are dynamically corrected. The EMB motor is driven to output the target torque, which is then transmitted to the ball screw of the caliper body after being reduced and amplified by the reducer. S5. The ball screw converts the rotational torque into linear motion, which pushes the screw nut and piston to move in sequence, thereby driving the friction plate to clamp the brake disc and generate mechanical braking force. At the same time, the dual closed-loop control system collects the clamping force feedback signal and the brake disc status feedback signal in real time, corrects the torque, and forms a closed-loop adjustment of braking force. S6. The deployed IoT sensors continuously collect data on the EMB motor operating parameters, reducer transmission efficiency, caliper clamping force stability, and brake disc status changes to build a full life cycle operation database. S7. Based on the full life cycle operation database, a parameter adjustment model is trained. The parameter adjustment model outputs optimized reducer transmission ratio parameters, EMB motor control gain and braking force extended state observer compensation coefficients. The modular unit parameter library is dynamically updated to achieve full life cycle adaptive optimization of braking performance.

5. The operating method of an electromechanical brake caliper for hub motor braking according to claim 4, characterized in that: Step S1 specifically includes the following steps: S11, synchronously acquiring ABS wheel speed via CAN bus. S11: Clamping force, motor torque, wheel speed, and vibration signals; S12: Use a 5th-order Butterworth high-pass filter to filter out low-frequency interference in the signals acquired in step S11; S13: Extract brake disc runout separately. Thickness variation and crack depth Feature parameters: ； ； ； ； In the formula, This represents the amplitude of linear velocity fluctuation, and ， This indicates the frequency corresponding to the wheel speed after the wheel linear velocity signal is transformed by FFT. The frequency domain amplitude at that point, and ， ， This represents the frequency domain function obtained by performing a Fourier transform (FFT) on the wheel linear velocity signal. Indicates the linear velocity of the wheel. ， This represents the wheel speed after noise reduction. Indicates the effective rolling radius of the wheel; This indicates the frequency corresponding to the wheel speed, and ， This represents the average angular velocity of the wheel speed signal after noise reduction; This represents the average value of the torque fluctuation of the EMB motor; Indicates the transmission efficiency of the reducer; Indicates the efficiency of the ball screw drive; Indicates the stiffness of the friction plate; Indicates the effective contact area of ​​the friction pads; This indicates the coefficient of friction between the friction pads and the brake disc; Represents the peak value of the power spectral density of the vibration signal; This represents the vibration-crack depth correction factor; S14. The extracted brake disc runout is normalized using Min-Max standardization. Thickness variation and crack depth The brake disc runout is obtained by standardization. Thickness variation and crack depth S15. Generate a brake disc status detection report and transmit it to the brake controller.

6. The operating method of an electromechanical brake caliper for hub motor braking according to claim 5, characterized in that: Step S2 specifically includes the following steps: S21, using the brake pedal displacement and speed to reflect the driver's braking intention, and combining vehicle speed and wheel-end load, converting it into a quantified braking intensity requirement through a calibration mapping relationship. and target deceleration ： ； In the formula, and These represent the displacement coefficient and the velocity coefficient, respectively. Indicates the displacement of the brake pedal; Indicates the speed of the brake pedal; Indicates braking intensity; S22: Dynamically allocate weights based on preset function priorities. ； ； In the formula, 、 and These represent the final safety weight, energy recovery weight, and component lifespan weight, respectively. 、 and These represent the basic safety weight, energy recovery weight, and component lifespan weight, respectively. ； and These represent the state correction factor and the operating condition correction factor, respectively. ， S23. Based on the target deceleration Calculate the total braking force and dynamically allocate the ratio of regenerative to mechanical braking based on functional weights: Total braking force requirement of the braking system ： Regeneration allocation ratio ： Mechanical braking distribution ratio ; Target value for regenerative braking ： Mechanical braking target value ： In the formula, Indicates the total mass of the vehicle; This indicates the maximum braking force of regenerative braking, and ， This indicates the maximum regenerative braking torque; S24, considering the brake disc condition level, a safety margin is added, and the target braking force value after adding the safety margin is converted into a torque command for the EMB motor, which is output to the dual closed-loop control system via the CAN bus; where, the target regenerative braking torque value The expression is as follows: Target value of mechanical braking torque The expression is as follows: In the formula, Indicates a safety margin, and 。 7. The operating method of an electromechanical brake caliper for hub motor braking according to claim 6, characterized in that: Step S3 specifically includes the following steps: S31, acquiring real-time regenerative braking torque through a torque sensor. The real-time regenerative braking torque was obtained by applying a moving average filter. S32. Based on the torque balance principle, and considering the transmission efficiency of the reducer. Calculate the mechanical braking torque compensation difference. ： ;in, In the formula, Indicates regenerative torque deviation; S33, compensates for the difference in mechanical braking torque. Using the basic target torque of the EMB motor as a reference, and adding a safety margin based on the condition of the brake disc, the target output torque of the EMB motor is determined. ： In the formula, This indicates the maximum output torque of the EMB motor.

8. The operating method of an electromechanical brake caliper for hub motor braking according to claim 7, characterized in that: Step S4 specifically includes the following steps: S41, Initialize the parameters of the feedforward second-order linear active disturbance rejection control algorithm based on the static characteristics of the EMB motor: ； ； ； ； In the formula, This indicates the bandwidth of the extended state observer; 、 and Both represent the extended state observer gain; Represents the feedforward coefficient; This represents the bandwidth of the feedforward second-order linear active disturbance rejection controller; This indicates the torque coefficient of the EMB motor; This represents the moment of inertia of the EMB motor. S42. Initialize the extended state observer state based on the static characteristics of the EMB motor, representing the armature resistance of the EMB motor. ， ， In the formula, 、 and All represent the state values ​​of the extended state observer; This indicates the initial value of the actual output torque of the EMB motor; Indicates the rate of change of torque; This represents the initial value of the total disturbance; S43, synchronously acquire the armature current and angular velocity of the EMB motor via the CAN bus, and calculate the actual output torque of the EMB motor using the motor dynamics model: ;in, In the formula, Indicates the EMB motor at time The actual output torque; This indicates the torque coefficient of the EMB motor; Indicates the EMB motor at time armature current; Indicates the EMB motor at time angular acceleration; and These represent the EMB motor at time [time]. and Angular velocity; S44, Treat the nonlinear disturbance during braking as a total disturbance, and incorporate feedforward coefficients. The extended state observer tracks torque output and disturbance changes in real time, and the discretized expression of the extended state observer is as follows: In the formula, 、 and Indicates time The actual output torque observation, torque change rate observation, and total disturbance observation; 、 and Indicates time The actual output torque observation, torque change rate observation, and total disturbance observation; 、 and express The rate of change of the observed values ​​at time points; S45. The total disturbance observation is verified based on the 3σ criterion combined with threshold constraints. The validity of the output is the total effective disturbance value. ： ;in, ； In the formula, and These represent the lower and upper limits of the total disturbance threshold, respectively; This represents the mean of the total disturbance sliding window; This represents the standard deviation of the total disturbance sliding window; Indicates time The effective total disturbance value; Indicates the sliding window size; S46. Based on the feedforward second-order linear active disturbance rejection law, combined with feedforward compensation and known disturbances, the EMB motor control voltage is corrected: ;in, ； ； ； In the formula, This indicates the corrected EMB motor control voltage; This indicates the control quantity after disturbance compensation; This indicates the maximum control voltage of the EMB motor; Indicates the basic control quantity; and Both represent PID feedback gain; This indicates the torque tracking error, and ； Indicates the rate of change of error; S47, the control voltage is converted through a three-phase full-bridge inverter. It is converted into motor drive current, which drives the EMB motor to output the target torque, and then transmitted to the ball screw through the reducer.

9. The operating method of an electromechanical brake caliper for hub motor braking according to claim 8, characterized in that: Step S5 specifically includes the following steps: S51, the motor torque is reduced and increased by the reducer and then transmitted to the ball screw, converting the rotational motion into linear motion, which pushes the piston forward; wherein, the ball screw shaft ， This indicates the actual output torque of the EMB motor; piston thrust. Piston displacement ， This indicates the cumulative rotation angle of the EMB motor, and S52, the piston thrust pushes the friction pads to clamp the brake disc, generating mechanical braking force through friction. ： S53, Calculate clamping force error By combining the brake disc status update, the target torque of the motor is dynamically corrected to form a closed-loop adjustment of braking force; among which, the corrected target torque The expression is as follows: ;in, In the formula, This indicates the amount of torque correction.

10. The method of operating an electromechanical brake caliper for hub motor braking according to claim 9, characterized in that: Step S7 specifically includes the following steps: S71, using the EMB motor operating parameters and optimization objectives from the full lifecycle operation database as input, and the optimal parameter adjustment amount as output, train a random forest model; its loss function... The expression is as follows: In the formula, 、 and All represent the weights of the loss function; Indicates braking response time; Indicates the maximum permissible response speed; Indicates the design life of the component; Indicates component lifespan; parameter adjustment amount ， S72 represents the input feature vector; with the optimization objectives of improving response speed, reducing clamping force error, and extending component life, the current EMB motor operating status parameters are input into the random forest model to obtain the parameter adjustment amount, and the optimal value is calculated by combining the original parameters; among them, the optimal transmission ratio of the reducer is... EMB motor optimal control gain ; Optimal compensation coefficients for extended state observers: ， ， In the formula, Indicates the original gear ratio of the reducer; This represents the gear ratio adjustment amount output by the random forest model; and This indicates the original EMB motor control gain; and This represents the EMB motor control gain adjustment amount output by the random forest model; 、 and This represents the gain of the optimal extended state observer; 、 、 This represents the compensation coefficient of the original extended state observer; 、 、 S73 represents the adjustment amount of the extended state observer compensation coefficient output by the random forest model; S74 writes the optimal value output by S72 into the modular unit parameter library and overwrites the original parameters, and verifies the performance improvement through actual vehicle operation.

Images