Electronic mechanical braking system of commercial vehicle

Abstract

The invention discloses an electronic mechanical braking system of a commercial vehicle, which relates to the technical field of automobile braking and comprises a signal input module, a system controller, four wheel end braking actuators, a multi-source sensor module and a communication module, the signal input module comprises a brake-by-wire pedal, an electronic parking button and an ADAS instruction interface, and is used for acquiring a brake intention and an external brake demand; the system controller adopts a double-vehicle-gauge-level MCU redundant architecture, and an FOC control algorithm and a fault diagnosis algorithm are embedded into the system controller. According to the electronic mechanical braking system for the commercial vehicle, the response time of the braking process is shortened from the traditional air braking response speed larger than 500 ms to within 70 ms, the response time is shortened by 86% compared with traditional braking, the response time is obviously shortened compared with an existing EBS (about 250 ms), the emergency braking distance can be shortened from 45 m of traditional braking to within 38 m at the vehicle speed of 100 km / h, the active safety is greatly improved, and the safety of the commercial vehicle is greatly improved. And all pneumatic and hydraulic components are omitted, so that the weight of the system is greatly reduced compared with that of a traditional commercial vehicle braking system.

Description

Technical Field

[0001] This invention relates to the field of automotive braking technology, specifically to an electromechanical braking system for commercial vehicles. Background Technology

[0002] The vehicle braking system is a core component that ensures driving safety. Traditional braking systems mainly rely on air or hydraulic transmission. In traditional air or hydraulic braking systems, the braking signal needs to be physically transmitted through air or hydraulic lines. The delay from pedal action to brake pad clamping is usually >500ms, which cannot meet the instantaneous response requirements of automatic emergency braking (AEB) and high-speed autonomous driving. In emergency scenarios, a delay of 100ms often leads to an increase in braking distance of 3-5m. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an electromechanical braking system for commercial vehicles, which solves the problems mentioned in the background section.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an electromechanical braking system for commercial vehicles, comprising a signal input module, a system controller, four wheel-end brake actuators, a multi-source sensor module, and a communication module; The signal input module includes a brake-by-wire pedal, an electronic parking button, and an ADAS command interface, which are used to collect braking intentions and external braking demands. The ADAS command interface receives braking demand signals from the AEB, automatic parking, and ADAS systems. The system controller adopts a dual automotive-grade MCU redundancy architecture, embedding FOC control algorithm and fault diagnosis algorithm, which are used to analyze signals, calculate braking force, control actuators and warn of faults. The wheel-end brake actuator is an independent intelligent module, including a torque motor, a planetary gear reducer, a ball screw transmission mechanism, an electromagnetic commutator clearance adjustment mechanism, and an electromagnetic brake parking mechanism, used to perform braking force output and parking; The multi-source sensor module includes a wheel speed sensor, a brake pad wear sensor, a motor temperature sensor, and a braking force sensor, which are used to provide feedback on the system status. The communication module supports the CANFD bus, which enables high-speed communication between the system and the vehicle's VCU and ADAS domain controller.

[0005] Furthermore, the commercial vehicle electromechanical braking system includes the following steps: Step 1: Distinguish between manned and unmanned driving states, and receive braking signals, vehicle speed, and battery SOC data.

[0006] Further, in the first step, data is collected by the steering wheel angle sensor, brake pedal pressure sensor, and accelerator pedal position sensor. If the sensors continuously detect operation signals such as steering wheel rotation and pedal pressure changes, it is determined as the manned driving state; when the sensors have no operation signal input for a long time and the vehicle is in the system ready state for autonomous driving, it is determined as the unmanned driving state.

[0007] Further, the commercial vehicle electro-mechanical braking system further includes the following steps: Step 2: Calculate the target braking force according to the braking demand and vehicle state, and adjust the distribution ratio of the electric motor braking force and the mechanical braking force in combination with the battery SOC.

[0008] Further, the calculation process of the target braking force is as follows: Collect the displacement signal of the driver stepping on the brake pedal through the brake pedal displacement sensor, and map the pedal displacement to the preset pedal-braking force relationship curve to initially estimate the required braking force , receive the active braking request signal sent by the system, and obtain the forced braking force demand under conditions such as emergency braking ; Use the wheel speed sensor to continuously monitor the rotation speeds of the four wheels , where , calculate the actual driving speed of the vehicle through the following formula : where, is the wheel rolling radius, according to the vehicle longitudinal acceleration sensor data , slope sensor data , through the formula: calculate the driving resistance correction value, where is the vehicle mass, is the gravitational acceleration, and the final target braking force:

[0009] Further, the distribution process of the electric motor braking force and the mechanical braking force is as follows: Read the state of charge SOC of the battery feedback by the battery management system BMS in real time. When SOC≥80%, set the upper limit of the electric motor braking force as the braking force corresponding to the rated torque of the motor. When 20%<SOC<80%, adjust according to a linear relationship. When SOC<20%, limit the electric motor braking force to to protect the battery; The linear relationship is the linear relationship between the input current of the motor and the generated braking force, and the magnitude of the current changes proportionally with the braking force; Establish a braking force distribution ratio function : When SOC ≥ 80% and , preferentially use electric braking, , while is the electric braking force distribution coefficient, and the mechanical braking force distribution coefficient is ; When 20% < SOC < 80%, according to and the current relationship, through: perform dynamic allocation to ensure ; When SOC < 20%, , at this time only use mechanical braking; According to the distribution coefficient , calculate the electric braking force , the mechanical braking force , and send them to the motor controller and the mechanical braking actuator respectively.

[0010] Furthermore, the electro-mechanical braking system of the commercial vehicle further includes the following steps: Step three: Drive the wheel-end braking actuator through the FOC algorithm to achieve the target braking force, and automatically compensate the braking gap based on the wear sensor data. Specifically: After the system starts, read the wear sensor data in real time to obtain the initial value of the gap between the current brake pads and the brake disc , and at the same time receive the target braking force command ; According to the target braking force , combined with the motor parameters of the wheel-end braking actuator, use the FOC field-oriented control algorithm to calculate the three-phase current command values required by the motor , , and the corresponding voltage vector angle , and the calculation process is as follows: Clarify the braking torque requirement , and calculate the quadrature-axis current reference value according to the motor torque formula , where , is the torque constant, is the quadrature-axis current; set the direct-axis current reference value , under the maximum torque current ratio control ; will be and converted from rotating coordinate system to stationary coordinate system, and the and , the inverse clark transformation formula is: According to the principle of space vector pulse width modulation (SVPWM), the position of the target voltage vector in the coordinate system is determined, and the voltage vector angle is calculated by the inverse tangent function: where and are the components of the target voltage vector in the coordinate system, which can be obtained by , combined with the motor model and control strategy; The calculated current command and voltage vector angle signal are sent to the drive circuit to drive the motor of the wheel end brake actuator to operate, pushing the brake pad to apply pressure to the brake disc to output the braking force ; The wear sensor data is continuously collected to obtain the current brake clearance , and the gap change amount is calculated. If exceeds the set threshold , the motor's rotation angle and torque are adjusted according to the gap change amount through the FOC algorithm to drive the brake actuator to act additionally, compensate for the brake clearance, and ensure stable braking force output. The actual braking force is monitored in real time by the pressure sensor, and compared with the target braking force . If there is a deviation , the motor drive parameters are fine-tuned again using the FOC algorithm until the actual braking force reaches the target value.

[0011] Further, the commercial vehicle electronic mechanical brake system further comprises the following steps: Step four: monitor system status, enable redundant control or adjacent wheel compensation when fault occurs; Step five: predict motor life and brake pad remaining thickness based on sensor historical data, and send maintenance prompt after reaching the warning threshold.

[0012] Further, the redundant control process is as follows: The system monitors the current, voltage and position signal of the EMB actuator in real time through sensors. If the main controller fails, the motor is stuck or the sensor data is abnormal, the redundancy switching mechanism is triggered immediately. The standby controller, such as a hot standby redundancy unit, receives the fault signal and takes over the brake control authority within 10 ms, calling the pre-stored brake parameters and control strategy. The standby power module is enabled to maintain the power supply of the braking system, while reducing the brake response speed to a safety threshold to avoid vehicle loss of control due to sudden performance changes. The redundancy system continuously synchronizes the main system historical data, and after the fault is repaired, it smoothly switches back to the main system operation, and records the fault log for subsequent analysis.

[0013] Further, the adjacent wheel compensation process is as follows: The wheel speed sensor detects that the single-wheel braking force is insufficient, such as brake disc wear exceeding the threshold, motor failure, and transmits the data to the central controller through the CAN bus. Based on the vehicle dynamics model, combined with the current vehicle speed, steering angle, load distribution, the additional braking torque required by the adjacent wheels is calculated; The motor drive current and brake caliper pressure of the adjacent wheels are corrected in real time to ensure that the vehicle yaw rate fluctuation is controlled within ±5° / s during the compensation process, maintaining driving stability; After the compensation is executed, the four-wheel braking force balance is continuously monitored. If the deviation is >15%, secondary compensation is started until the vehicle returns to normal braking state.

[0014] The present application provides a kind of commercial vehicle electronic mechanical brake system, with the following beneficial effects: 1. The commercial vehicle electronic mechanical brake system, the brake process response time of this system is reduced from the traditional air pressure brake response speed from more than 500 ms to within 70 ms, which is 86% shorter than the traditional brake, and also significantly shorter than the existing EBS (about equal to 250 ms). At a speed of 100 km / h, the emergency braking distance can be shortened from 45 m of traditional brake to within 38 m, greatly improving active safety, and eliminating all air and hydraulic components, greatly reducing the weight of the system compared to the traditional commercial vehicle brake system. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 It is a whole step flowchart of the commercial vehicle electronic mechanical brake system of the present application; Fig. 2 It is a multi-dimensional characteristic comparison diagram of the commercial vehicle electronic mechanical brake system of the present application and traditional air pressure brake and electric control air pressure brake. DETAILED DESCRIPTION

[0016] The embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0017] As shown in Figs. 1-2 The present application provides a technical solution: a commercial vehicle electronic mechanical brake system, comprising a signal input module, a system controller, four wheel end brake actuators, a multi-source sensor module and a communication module; The signal input module includes a line control brake pedal, an electronic parking button and an ADAS instruction interface, which is used to collect braking intention and external braking demand, wherein the ADAS instruction interface receives braking demand signals of AEB, automatic parking and ADAS system; The system controller adopts a dual vehicle-level MCU redundant architecture, embeds FOC control algorithm and fault diagnosis algorithm, and is used to analyze signals, calculate braking force, control actuators and warn faults; The wheel end brake actuator is an independent intelligent module, which includes a torque motor, a planetary gear reducer, a ball screw transmission mechanism, an electromagnetic commutator gap adjustment mechanism and an electromagnetic brake parking mechanism, and is used to execute brake force output and parking; The multi-source sensor module includes a wheel speed sensor, a brake pad wear sensor, a motor temperature sensor and a brake force sensor, which is used to feedback system status; The communication module supports CANFD bus, which is used to realize high-speed communication between the system and the vehicle VCU and ADAS domain controller.

[0018] The commercial vehicle electronic mechanical brake system comprises the following steps: Step one: distinguish between manned and unmanned driving states, receive braking signals, vehicle speed and battery SOC data; Among them, through the steering wheel angle sensor, brake pedal pressure sensor, accelerator pedal position sensor to collect data If the sensor continuously detects steering wheel rotation, pedal pressure change operation signal, it is determined as manned driving state; When the sensor has no operation signal input for a long time, and the vehicle is in a system ready state that can be automatically driven, it is determined as unmanned driving state; Step two: calculate the target braking force according to the braking demand and vehicle state, and adjust the distribution ratio of motor braking force and mechanical braking force combined with battery SOC; The target braking force calculation process is as follows: Collect the displacement signal of the driver stepping on the brake pedal through the brake pedal displacement sensor, map the pedal displacement With the preset pedal-braking force relationship curve To preliminarily estimate the demand braking force , receives the active braking request signal sent by the system, and obtains the forced braking force demand under the emergency braking and other working conditions ; The wheel speed sensor is used to monitor the rotational speed of the four wheels in real time , wherein The actual driving speed of the vehicle is calculated by the following formula : wherein, is the rolling radius of the wheel, which is calculated according to the vehicle longitudinal acceleration sensor data , the slope sensor data , through the formula: The driving resistance correction value is calculated, wherein is the mass of the vehicle, is the acceleration of gravity, and the final target braking force is: The distribution process of the motor braking force and the mechanical braking force is as follows: The battery state of charge SOC fed back by the battery management system BMS is read in real time, and when SOC≥80%, the upper limit of the motor braking force is set is the braking force corresponding to the rated torque of the motor, when 20%<SOC<80%, it is adjusted according to a linear relationship, when SOC<20%, the motor braking force is limited to to protect the battery; Wherein the linear relationship is the linear relationship between the motor input current and the generated braking force, and the current size and the braking force change in direct proportion; The braking force distribution ratio function is established : When SOC≥80% and , the motor braking is preferred, , and is the motor braking force distribution coefficient, and the mechanical braking force distribution coefficient is ; When 20%<SOC<80%, according to the relationship between and the current , through: Dynamic distribution is carried out to ensure ; When SOC<20%, only mechanical braking is used at this time ; According to the distribution coefficient , the motor braking force Mechanical braking force , and are sent to the motor controller and the mechanical brake actuator, respectively; Step three: drive the wheel-end brake actuator through the FOC algorithm to achieve the target braking force, and automatically compensate for the brake clearance based on the wear sensor data, specifically: After the system starts, read the wear sensor data in real time to obtain the initial value of the gap between the current brake pad and the brake disc , while receiving the target braking force command ; According to the target braking force , combined with the motor parameters of the wheel-end brake actuator, the FOC magnetic field orientation control algorithm is used to calculate the three-phase current command value required by the motor 、 、 and the corresponding voltage vector angle , the calculation process is as follows: Clarify the braking torque demand , according to the motor torque formula Calculate the quadrature axis current reference value , where is the torque constant, is the quadrature axis current; Set the direct axis current reference value , under the maximum torque current ratio control ; Convert and from rotating coordinate system to stationary coordinate system through inverse Park transformation, get and , the inverse Clarke transformation formula is: According to the principle of space vector pulse width modulation (SVPWM), determine the position of the target voltage vector in the coordinate system, calculate the voltage vector angle through the inverse tangent function: Where and are the components of the target voltage vector in the coordinate system, which can be obtained by , combined with the motor model and control strategy; Send the calculated current command and voltage vector angle signal to the drive circuit to drive the motor of the wheel-end brake actuator to run, push the brake pad to apply pressure to the brake disc, and output the braking force ; Continuously collect wear sensor data to obtain the current brake clearance , calculate the clearance change , if exceeds the set threshold , adjust the rotation angle and torque of the motor according to the clearance change through the FOC algorithm, drive the brake actuator to act additionally, compensate for the brake clearance, and ensure stable brake force output; Real-time monitoring of actual brake force by pressure sensor , and comparison with target brake force , if there is a deviation , fine-tune the motor drive parameters again using the FOC algorithm until the actual brake force reaches the target value; Step four: monitor system status, enable redundant control or adjacent wheel compensation when fault occurs; Step five: predict motor life and brake pad remaining thickness based on sensor historical data, and send maintenance prompt when reaching the warning threshold; The redundant control process is as follows: The system monitors the current, voltage and position signals of the EMB actuator in real time through the sensor, and immediately triggers the redundant switching mechanism if it detects a main controller failure, motor jamming or abnormal sensor data; The standby controller, such as the hot standby redundant unit, receives the fault signal and takes over the brake control authority within 10ms, and calls the pre-stored brake parameters and control strategy; Enable the standby power supply module to maintain the power supply of the brake system, while reducing the brake response speed to a safety threshold to avoid vehicle loss of control due to sudden performance changes; The redundant system continuously synchronizes the main system historical data, and after the fault is repaired, it smoothly switches back to the main system operation, and records the fault log for subsequent analysis; The adjacent wheel compensation process is as follows: The wheel speed sensor detects insufficient single-wheel brake force, such as brake disc wear exceeding the threshold or motor failure, and transmits the data to the central controller through the CAN bus; Based on the vehicle dynamics model, combined with the current vehicle speed, steering angle, load distribution, calculate the additional brake torque required by the adjacent wheels; Real-time correction of motor drive current and brake caliper pressure of adjacent wheels to ensure that the vehicle yaw rate fluctuation is controlled within ±5° / s during compensation to maintain driving stability; After compensation, continuously monitor the balance of four-wheel brake force, if the deviation > 15%, start secondary compensation until the vehicle returns to normal braking state.

[0019] Taking the "AEB emergency braking at 100km / h" scenario as an example, the control method execution steps are as follows: Signal receiving: the ADAS system (such as laser radar + camera fusion) detects a stationary obstacle 50 m in front, sends an AEB instruction (target braking deceleration 8 m / s2, duration 2 s) to the system controller through CANFD; at the same time, the wheel speed sensor feedbacks the current vehicle speed 100 km / h, and the battery SOC is 60%; Braking force calculation: The system controller calculates the total target braking force through the PID algorithm: according to the total mass of the electric truck 49 tons and the deceleration 8 m / s2, the total braking force demand = 49000 kg x 8 m / s2= 392000 N, which is evenly distributed to four wheels (each wheel target braking force 98000 N); Energy recovery coordination: SOC = 60%, set the motor braking force proportion to 50% (49000 N / wheel), the mechanical braking force proportion to 50% (49000 N / wheel), and send the motor braking force demand to the powertrain; Actuator control: The system controller sends control instructions to four wheel-end brake actuators, and the FOC algorithm drives the torque motor to operate, after planetary gear reduction (1:28) and ball screw transmission (lead 5 mm), the brake pad is pushed to clamp the brake disc, and the target mechanical braking force 49000 N is reached within 15 ms; Gap adjustment: the wear sensor feedbacks the current brake gap 0.05 mm (within the range of ≤0.06 mm), no compensation is needed; Fault monitoring: during braking, the temperature sensor feedbacks the motor temperature 65℃ (<120℃ threshold), and the current 12A (<15A overcurrent threshold), no fault; Braking end: after 2 s, the ADAS system sends a brake release instruction, the system controller controls the motor to reverse, the brake pad returns to the original position, the motor braking force gradually decreases to 0, and the mechanical braking force is synchronously released, the whole braking process response time is 65 ms, and the braking distance is 37.2 m.

[0020] Based on the above description, compared with the traditional gas or hydraulic braking system, please refer to Fig. 2 ( Fig. 2 For multi-dimensional characteristic comparison diagram of the system and traditional gas pressure braking, electric control gas pressure braking), from the comparison results, it can be seen that the system reduces the braking process response time from the traditional gas pressure braking response speed from more than 500 ms to less than 70 ms, which is 86% shorter than the traditional braking, and is also significantly shorter than the existing EBS (about equal to 250 ms), the emergency braking distance at 100 km / h vehicle speed can be shortened from 45 m of traditional braking to less than 38 m, which greatly improves the active safety, and cancels all gas and hydraulic components, the system weight is greatly reduced compared with the traditional commercial vehicle braking system.

[0021] The embodiments of the present application are presented by way of example and description, and are not intended to be exhaustive or to limit the application to the form disclosed. Many modifications and variations will be apparent to those skilled in the art. Embodiments are chosen and described in order to best explain the principles of the application and its practical application, and to thereby enable others skilled in the art to best utilize the application in various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

1. A commercial vehicle electromechanical brake system characterized by: The system comprises a signal input module, a system controller, four wheel-end brake actuators, a multi-source sensor module and a communication module. The signal input module comprises a line control brake pedal, an electronic parking button and an ADAS instruction interface, which are used to collect braking intention and external braking demand, wherein the ADAS instruction interface receives braking demand signals of AEB, automatic parking and ADAS systems. The system controller adopts a dual vehicle-level MCU redundant architecture, embeds a FOC control algorithm and a fault diagnosis algorithm, and is used to analyze signals, calculate braking force, control actuators and warn faults. The wheel-end brake actuators are independent intelligent modules, which comprise a torque motor, a planetary gear reducer, a ball screw transmission mechanism, an electromagnetic commutator gap adjustment mechanism and an electromagnetic brake holding mechanism, and are used to execute brake force output and parking. The multi-source sensor module comprises a wheel speed sensor, a brake pad wear sensor, a motor temperature sensor and a brake force sensor, which are used to feedback system status. The communication module supports CANFD bus, which is used to realize high-speed communication between the system and a vehicle VCU and an ADAS domain controller.

2. An electromechanical brake system for a commercial vehicle according to claim 1, characterized in that: The commercial vehicle electronic mechanical brake system comprises the following steps: Step one: distinguishing between manned and unmanned driving states, receiving braking signals, vehicle speed and battery SOC data.

3. An electro-mechanical brake system for a commercial vehicle according to claim 2, characterized in that: In the step one, data is collected through a steering wheel angle sensor, a brake pedal pressure sensor and a throttle pedal position sensor.

4. An electro-mechanical brake system for a commercial vehicle according to claim 3, characterized in that: The commercial vehicle electronic mechanical brake system further comprises the following steps: Step two: calculating a target braking force according to braking demand and vehicle status, and adjusting the distribution ratio of motor braking force and mechanical braking force in combination with battery SOC.

5. An electro-mechanical brake system for a commercial vehicle according to claim 4, characterized in that: The target braking force calculation process is as follows: The displacement signal of the driver stepping on the brake pedal is collected by a brake pedal displacement sensor, and the pedal displacement amount is mapped with the preset pedal-brake force relationship curve to preliminarily estimate the required brake force The active brake request signal sent by the system is received to obtain the forced brake force demand under the emergency braking condition ; Real-time monitoring of the rotational speed of the four wheels using wheel speed sensors wherein The actual driving speed of the vehicle is calculated by the following equation : wherein, is the wheel rolling radius, according to vehicle longitudinal acceleration sensor data , gradient sensor data by the formula: The running resistance correction value is calculated, wherein is the vehicle mass, is the gravitational acceleration, final target braking force: 。 6. An electromechanical brake system for a commercial vehicle as defined in claim 4, wherein: The distribution process of the motor braking force and the mechanical braking force is as follows: Real-time reading of battery state of charge SOC feedback by battery management system BMS, when SOC≥80%, set the motor braking force upper limit For the rated torque of the motor corresponding to the braking force, when 20%<SOC<80%, Adjust according to linear relationship, when SOC<20%, limit the motor braking force to To protect the battery; The linear relationship is a linear relationship between motor input current and generated braking force, and the current size and the braking force change in direct proportion; Establishing a brake force distribution ratio function : When SOC≥80% and the motor braking is adopted preferentially, and is the motor braking force distribution coefficient, and the mechanical braking force distribution coefficient is ; When 20% < SOC < 80%, according to the relationship with the current is given by: Dynamic allocation is performed to ensure ; When SOC < 20%, At this time only mechanical braking is used; According to the distribution coefficient , the motor braking force , the mechanical braking force , and are respectively sent to the motor controller and the mechanical braking actuator.

7. An electro-mechanical brake system for a commercial vehicle according to claim 6, characterized in that: The commercial vehicle electronic mechanical brake system further comprises the following steps: Step three: driving the wheel-end brake actuators through a FOC algorithm to achieve the target braking force, and automatically compensating for brake clearance based on wear sensor data, specifically: After the system starts, the wear sensor data is read in real time to obtain the initial value of the gap between the current brake pad and the brake disc while receiving a target braking force command ; According to the target braking force , combined with the motor parameters of the wheel end brake actuator, the required three-phase current command value of the motor is calculated by the FOC magnetic field orientation control algorithm 、 、 and the corresponding voltage vector angle , the calculation process is as follows: Clearly braking torque demand , according to motor torque formula Calculate the quadrature axis current reference value , wherein, is the torque constant, is the quadrature axis current; Set the direct axis current reference value Under maximum torque current ratio control ; The and by the inverse park transformation from rotating coordinate system to stationary coordinate system, get and , the inverse Clark transformation formula is: According to the principle of space vector pulse width modulation (SVPWM), the position of the target voltage vector in the coordinate system is determined, and the voltage vector angle is calculated by an inverse tangent function The coordinate system is determined, and the voltage vector angle is calculated by an inverse tangent function : wherein and are components of the target voltage vector in the coordinate system, which can be derived from , in combination with the motor model and control strategy; The calculated current command and voltage vector angle signal are sent to a driving circuit, the motor of the wheel end brake actuator is driven to operate, the brake pad is pushed to apply pressure to the brake disc, and the brake force is output ; Continuously collect wear sensor data to obtain the current brake clearance , calculate the clearance change , if exceeds the set threshold , adjust the rotation angle and torque of the motor according to the clearance change through the FOC algorithm, drive the brake actuator to act additionally, compensate the brake clearance, and ensure the stable brake force output. The actual braking force is monitored in real time by a pressure sensor and compared with the target braking force If there is a deviation the motor drive parameters are again fine-tuned using the FOC algorithm until the actual braking force reaches the target value.

8. An electro-mechanical brake system for a commercial vehicle according to claim 7, characterized in that: The commercial vehicle electronic mechanical brake system further comprises the following steps: Step four: monitoring system status, and enabling redundant control or adjacent wheel compensation when a fault occurs; Step five: predicting motor life and brake pad remaining thickness based on sensor historical data, and sending a maintenance prompt after reaching a warning threshold.

9. An electro-mechanical brake system for a commercial vehicle according to claim 8, characterized in that: The redundant control process is as follows: The system monitors the current, voltage and position signals of the EMB actuators in real time through sensors. The standby controller receives the fault signal, takes over the braking control authority within 10 ms, and calls pre-stored braking parameters and control strategies. The standby power module is enabled to maintain the power supply of the braking system, while reducing the braking response speed to a safety threshold to avoid vehicle out-of-control caused by performance mutation; The redundant system continuously synchronizes the history data of the main system, and after the fault is repaired, it is switched back to the main system operation smoothly, and records the fault log for subsequent analysis.

10. An electro-mechanical brake system for a commercial vehicle according to claim 8, characterized in that: The adjacent wheel compensation process is as follows: The wheel speed sensor detects that the single-wheel braking force is insufficient, such as brake disc wear exceeding the threshold, motor failure, and transmits the data to the central controller through the CAN bus; Based on the vehicle dynamics model, combined with the current vehicle speed, steering angle, load distribution, the additional braking torque required by the adjacent wheel is calculated; The motor drive current and brake caliper pressure of the adjacent wheel are corrected in real time to ensure that the vehicle yaw rate fluctuation is controlled within ±5° / s during the compensation process, and the driving stability is maintained; After the compensation is executed, the four-wheel braking force balance is continuously monitored, and if the deviation is >15%, secondary compensation is started until the vehicle returns to normal braking state.

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