Electromechanical brake system and control method therefor

Abstract

Provided in the present application is an electromechanical brake system. Also disclosed is a control method for an electromechanical brake system. The method comprises: mounting a force sensor on at least one wheel of a vehicle; the wheel that is provided with the force sensor acquiring clamping force information by means of the force sensor; performing contact recognition in light of a motor current, updating the contact-point stroke of a piston, and calculating the piston position on the basis of motor angle information; for a wheel without a force sensor, performing contact calculation by means of acquiring vehicle parameters and the motor current, so as to obtain piston position information; by means of using the clamping force information of the wheel provided with the force sensor and the motor parameters of the wheel without a force sensor, performing stiffness fitting to determine an estimated clamping force of other wheels; and finally, performing a clamping or releasing operation on the basis of the acquired information.

Description

Electromechanical braking system and its control method

[0001] This application claims priority to Chinese Patent Application No. 202411205388.9, filed with the Chinese Patent Office on August 30, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of vehicle electronic control technology, and in particular to an electromechanical braking system, as well as a control method for the electromechanical braking system. Background Technology

[0003] With the development of automotive electronics and intelligence, electronic mechanical braking systems have gradually become an indispensable component of advanced driver assistance systems (ADAS) and autonomous driving technologies.

[0004] Electronic mechanical braking is an important technology in modern automotive braking systems. It uses an electric motor as the driving source of braking force, and converts the motor's power into braking force through a mechanical transmission mechanism to clamp the vehicle's brake disc or brake drum, thereby achieving the purpose of braking.

[0005] Clamping force control in electronic braking systems (EMB) is a crucial prerequisite for realizing the system's basic functions, including active braking, traction control, and anti-lock braking. Accurate identification of the clamping force is key to clamping force control. However, the clamping force sensors in current EMB systems are expensive, posing a cost issue for automakers to widely adopt them in mass-produced vehicles.

[0006] Furthermore, the placement of the clamping force sensor also faces many challenges. For example, placing it too close to the friction lining can shorten its lifespan due to excessively high operating temperatures, while placing it deep within the EMB can cause hysteresis problems that affect measurement accuracy. Completely eliminating the clamping force sensor would increase the difficulty of accurately identifying the clamping force and make it difficult to determine the wear condition of the friction lining, thus affecting the control effect of the clamping force.

[0007] Given the problems existing in the aforementioned related technologies, how to accurately identify and control the clamping force in the EMB system is the problem that this application aims to solve.

[0008] Summary of the Invention

[0009] One objective of this application is to provide an electromechanical braking system that addresses the accuracy and reliability issues of traditional mechanical braking systems. This system, through modular design, achieves high precision braking operation, rapid response, and redundant braking capabilities.

[0010] To solve the above-mentioned technical problems, this application provides an electromechanical braking system, comprising:

[0011] The control module is configured to send operation commands;

[0012] The execution module includes a main execution module and a secondary execution module. The main execution module is equipped with a force sensor and obtains the clamping force through contact recognition, while the secondary execution module obtains the estimated clamping force through contact calculation.

[0013] In some embodiments, the main execution module includes:

[0014] The motor and the speed reduction and torque amplification mechanism are configured to provide the necessary clamping or releasing power.

[0015] The motion conversion mechanism is connected to the motor and the reduction and torque amplification mechanism, and converts the rotational motion of the motor into linear motion. The force sensor is integrated into the motion conversion mechanism and is set to measure the clamping force.

[0016] A motor position sensor, integrated into the motor or motor controller, is configured to sense the rotation angle of the motor in real time.

[0017] A current sensor, integrated into the motor or motor controller, is configured to sense the magnitude of the motor current in real time.

[0018] In some embodiments, the electromechanical braking system further includes a controller connected to the motor position sensor, the current sensor, and the force sensor, configured to receive instructions from the control module and control the rotation of the motor based on real-time information from the motor position sensor, the current sensor, and the force sensor to perform clamping or releasing operations.

[0019] In some embodiments, the secondary execution module includes a calculation unit configured to calculate and estimate the clamping force based on the clamping force data and / or other relevant parameters of the main execution module using a preset algorithm, so as to provide redundancy or auxiliary braking.

[0020] Another objective of this application is to provide a control method for an electromechanical braking system, which achieves precise control of clamping force and effective monitoring of friction lining wear by optimizing sensor arrangement and clamping force identification method.

[0021] This application discloses a control method for an electromechanical braking system, which involves installing force sensors on the wheels of a vehicle; the control method includes the following steps:

[0022] Obtain vehicle parameters and send them to the contact calculation module; perform contact calculations based on the vehicle parameters and motor current;

[0023] If vehicle parameters are not required, contact calculations are performed based on the motor current.

[0024] Based on the above contact calculation, the piston position is calculated according to the motor angle information of the powerless sensor wheel to obtain the piston position information of the powerless sensor wheel.

[0025] Based on the clamping force information of the wheel with force sensor, the motor current and motor angle of the wheel without force sensor, stiffness fitting is performed to determine the estimated clamping force of other wheels.

[0026] Based on the information obtained from the above steps, perform clamping or releasing.

[0027] In some embodiments, after obtaining the estimated clamping force through stiffness fitting and before performing the clamping operation, a friction identification step is further included, in which the friction torque required for friction compensation control is identified by the motor current, motor speed and estimated clamping force.

[0028] In some embodiments, the stiffness fitting method includes receiving clamping force and piston position information from a force sensor wheel, performing data fitting to obtain a functional relationship between clamping force and piston position, and then calculating an estimated clamping force based on the piston position information of a wheel without a force sensor using this functional relationship.

[0029] In some embodiments, the method includes a force sensor wheel control method based on a single force sensor on a vehicle wheel and a force sensor wheel control method based on two force sensors on a vehicle wheel.

[0030] In some embodiments, the method for controlling a vehicle wheel without a force sensor based on a single force sensor mounted on the vehicle wheel is as follows:

[0031] When a force sensor is installed on one of the wheels of a vehicle, but not on the other wheels, determine whether the conditions for triggering contact calculation are met.

[0032] If the conditions are met, proceed with the following steps:

[0033] Obtain vehicle parameter information; perform contact calculations based on the obtained vehicle parameter information and motor current;

[0034] First, the piston position is calculated based on the motor angle; then, the clamping force of the force sensor wheel, the piston position information, and the piston position information of the corresponding force sensor wheel are used for stiffness fitting to obtain the estimated clamping force.

[0035] Then, based on the motor current, motor speed, and estimated clamping force, the friction torque required for friction compensation control is identified.

[0036] Finally, determine and execute the clamp / release command;

[0037] If the conditions are not met, proceed with the following steps:

[0038] First, calculate the piston position based on the motor angle;

[0039] Then, by using the clamping force and piston position information of the force sensor wheel, as well as the current piston position information of the wheel, stiffness fitting is performed to obtain the estimated clamping force.

[0040] Then, based on the motor current, motor speed, and estimated clamping force, the friction torque required for friction compensation control is identified.

[0041] Finally, determine and execute the clamp / release command.

[0042] The method for controlling the vehicle wheel without force sensors, based on two force sensors installed on the vehicle wheel, is as follows:

[0043] Force sensors are installed on two of the vehicle's wheels, while force sensors are not installed on the other wheels;

[0044] First, determine whether the conditions for triggering contact calculation are met:

[0045] If the conditions are met, proceed with the following steps:

[0046] First, perform contact calculations based on the motor current; then, calculate the piston position based on the motor angle.

[0047] Then, based on the clamping force information and piston position information of the wheel with the force sensor, and the piston position information of the wheel without the force sensor, stiffness fitting is performed to obtain the estimated clamping force.

[0048] Then, based on the motor current, motor speed, and estimated clamping force, the friction torque required for friction compensation control is identified.

[0049] Finally, determine and execute the clamp / release command;

[0050] If the conditions are not met, proceed with the following steps:

[0051] First, the piston position is calculated based on the motor angle; then, stiffness fitting is performed using the clamping force of the wheel with force sensor and the piston position information, as well as the piston position information of the wheel without force sensor, to obtain the estimated clamping force.

[0052] Then, based on the motor current, motor speed, and estimated clamping force, the friction torque required for friction compensation control is identified.

[0053] Finally, determine and execute the clamp / release command. Attached Figure Description

[0054] The accompanying drawings, which are provided to further illustrate this application and form part of this application, are intended to explain this application and do not constitute an undue limitation of this application.

[0055] Figure 1 is a schematic diagram of the control principle of the electromechanical braking system in this application;

[0056] Figure 2 is a flowchart of the overall clamping force control of four wheels based on a single force sensor in this application;

[0057] Figure 3 is a flowchart of the four-wheel overall clamping force control based on two force sensors in this application;

[0058] Figure 4 is a flowchart of the wheel clamping force control based on one or two force sensors in this application.

[0059] Figure 5 is a flowchart of the wheel clamping force control based on a single force sensor according to this application;

[0060] Figure 6 is a flowchart of the wheel clamping force control based on two force sensors according to this application. Detailed Implementation

[0061] Various exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the scope of this application or its application or use. This application may be implemented in other different forms and is not limited to the embodiments described herein.

[0062] The clamping force sensors currently used in EMB systems are expensive, making widespread adoption by automakers in mass-produced vehicles difficult. Furthermore, placing the clamping force sensor too close to the friction lining can shorten its lifespan due to excessively high operating temperatures, while placing it deep within the EMB can cause hysteresis, affecting measurement accuracy. Completely eliminating the clamping force sensor would prevent accurate identification of the clamping force, leading to problems such as the inability to determine the wear condition of the friction lining. This application provides a technical solution to address these issues. The technical solution, working principle, and technical effects of this application are detailed below with specific embodiments.

[0063] This application utilizes an electric braking system to identify and control clamping force. The electric braking system includes a main controller, an electromechanical braking system, and a brake disc. The main controller and the electromechanical braking system control the clamping of the brake disc, generating the required clamping force or estimating the clamping force signal, and transmitting this signal to each wheel via an IVN (vehicle network).

[0064] Referring to Figure 1, the electromechanical braking system includes a control module and an execution module.

[0065] The control module is configured to send operation commands, while the execution module is responsible for performing clamping or releasing operations based on the commands. The execution module is further subdivided into a main execution module and a secondary execution module to improve the system's reliability and redundancy.

[0066] The main actuator module is the core of the braking system. It includes the motor and reduction and torque amplification mechanism, motion conversion mechanism, motor position sensor, and current sensor, all integrated within the motor or motor controller. The motor position sensor and current sensor provide real-time feedback, enabling the controller to precisely control the motor's rotation angle and current magnitude.

[0067] The motor and reduction and torque-increasing mechanism provide the necessary clamping or releasing power, while the motion conversion mechanism converts the rotational motion of the motor into linear motion to achieve braking operation.

[0068] The force sensor is integrated into the motion conversion mechanism and is set to measure the clamping force in real time to ensure the accuracy and stability of the braking effect.

[0069] The secondary execution module, serving as a redundancy or auxiliary component to the main execution module, includes a calculation unit. This calculation unit calculates and estimates the clamping force based on the clamping force data and / or other relevant parameters from the main execution module using a preset algorithm. Thus, in the event of a failure in the main execution module, the secondary execution module can take over the braking task, providing redundant braking capability and enhancing the system's reliability and safety.

[0070] The controller is the "brain" of the braking system. It is connected to the motor position sensor, current sensor, and force sensor, receives commands from the control module, and controls the motor's rotation based on real-time information from these sensors. By precisely controlling the motor's rotation angle and current, the controller can perform precise clamping or releasing operations.

[0071] During operation, the control module sends operation commands to the controller, which controls the motor's rotation based on the commands and real-time information from the sensors. The main execution module provides power through the motor and the reduction and torque amplification mechanism, while the motion conversion mechanism converts the rotational motion into linear motion, thus achieving the braking operation.

[0072] Specifically, when the control module sends a braking command, the controller receives the command and precisely controls the motor's rotation based on real-time information from the motor position sensor, current sensor, and force sensor. The motor provides the necessary power through a reduction and torque amplification mechanism, driving the motion conversion mechanism to convert rotational motion into linear motion, thereby achieving clamping or releasing operations. The force sensor measures the clamping force in real time to ensure the accuracy and stability of the braking effect. Simultaneously, the secondary execution module calculates and predicts the clamping force based on the clamping force data from the primary execution module and / or other relevant parameters to provide redundant or auxiliary braking, enhancing the system's reliability and safety.

[0073] As shown in Figures 2 and 3, based on the above-mentioned electromechanical braking system, this application discloses a control method for the electromechanical braking system. Based on this method, the functional modules are first described as follows:

[0074] Upper-level control system: configured to issue commands to control the clamping / releasing of the actuators.

[0075] Vehicle parameters: The single force sensor scheme sends vehicle parameters such as the front-to-back braking force distribution ratio, which affect the wear difference of friction linings, to the contact calculation module in each wheel without a force sensor.

[0076] Contact point identification: The system is set to update the piston's contact point stroke in the force sensor wheel based on the changes in clamping force obtained from the force sensor and the changes in motor current of the wheel's actuator, thereby determining the wear condition of the friction lining and achieving adaptive compensation of the friction lining.

[0077] Contact calculation: The system is set to update the piston's contact point stroke in the wheel with no force sensor based on the contact point identification module in the wheel with force sensor, combined with the change in motor current of the actuator of that wheel, so as to determine the wear condition of the friction lining and realize the adaptive compensation of the friction lining.

[0078] Piston position calculation: The piston position is obtained by integrating the motor angle sensed in real time by the motor position sensor and the actuator parameters.

[0079] Force sensor: senses clamping force and transmits the clamping force from the wheel with the force sensor to each wheel with the force sensor.

[0080] Stiffness fitting: The stiffness fitting is performed by receiving the clamping force and piston position information of the force sensor wheel in the unforced sensor wheel, and then the estimated clamping force is obtained based on the piston position of the wheel.

[0081] Friction identification: In wheels with a force sensor, the friction torque required for friction compensation control is identified based on motor current, motor speed, and clamping force. In wheels without a force sensor, the friction torque required for friction compensation control is identified based on motor current, motor speed, and estimated clamping force.

[0082] Execution layer clamping / release control: When the upper control system issues a clamping / release command, the force sensor wheel executes the motor drive based on the piston position, contact point stroke and clamping force to complete the clamping or release of the friction liner replacement control of the actuator. The forceless sensor wheel executes the motor drive based on the piston position, contact point stroke and the estimated clamping force obtained by the stiffness fitting module to complete the clamping or release of the actuator.

[0083] Actuator: Responds to the motor torque and completes the braking requirement by converting the motor torque into a clamping force acting on the brake disc.

[0084] As shown in Figures 2 and 4, based on the above description, the following describes a wheel clamping force control method based on a single force sensor, where a force sensor is installed on one of the four wheels of a vehicle, while the other three wheels do not have force sensors installed:

[0085] Step S101: Directly obtain the clamping force value of the wheel through the clamping force sensor;

[0086] Step S102: Determine whether the conditions for triggering contact recognition are met:

[0087] If the conditions are met, contact identification is performed based on motor current and clamping force, and the piston position is calculated based on motor rotation angle.

[0088] Then, the frictional torque required for friction compensation control is identified based on the motor current, motor speed, and clamping force.

[0089] If the conditions are not met, the piston position is calculated directly based on the motor rotation angle; then the friction torque required for friction compensation control is identified based on the motor current, motor speed, and clamping force.

[0090] Step S103: Determine whether a clamping / releasing command has been received from the upper control system:

[0091] If received, execute the corresponding command based on the clamping force and piston position;

[0092] If not received, the clamping / releasing action will not be performed.

[0093] Combining the above steps, the specific implementation process is as follows:

[0094] The real-time clamping force value is obtained directly from the clamping force sensor installed on the wheel or braking system.

[0095] After obtaining the clamping force value, a judgment is made on whether the conditions for triggering contact recognition are met.

[0096] a: If the conditions for triggering contact recognition are met:

[0097] Contact identification is performed based on changes in motor current and clamping force. This step is typically to determine whether the wheel and brake disc are in close contact, ensuring that subsequent control actions can be executed accurately.

[0098] Next, the piston position is calculated based on the change in motor rotation angle. The functional relationship between the motor rotation angle and the piston position is as follows:

[0099] s represents the piston position, θ represents the mechanical angle of motor rotation, k represents the transmission ratio of the reduction and torque-increasing mechanism, p represents the thread pitch, and r represents the pitch circle radius.

[0100] The current position of the piston can be indirectly determined by measuring the motor rotation angle.

[0101] If a clamping / releasing command is received from the upper control system at this time, the corresponding command will be executed according to the current clamping force and piston position.

[0102] For example, if the command is to clamp and the current clamping force has not reached the set value, the motor current is increased to increase the clamping force; if the command is to release, the motor current is decreased to reduce the clamping force.

[0103] If no clamping / releasing command is received, no clamping or releasing action will be performed, and the current state will be maintained.

[0104] b: If the conditions for triggering contact recognition are not met:

[0105] The piston position is calculated directly based on the change in motor rotation angle, skipping the contact recognition step.

[0106] The subsequent steps are the same as when the conditions are met, that is, to perform the corresponding clamping / releasing action or maintain the current state according to the instructions and the current state.

[0107] In some implementations, as shown in Figures 3 and 4, when force sensors are installed on two of the four wheels of a vehicle, and no force sensors are installed on the other wheels, the wheel clamping force control method based on two force sensors is the same as the wheel clamping force control method based on a single force sensor, and will not be described in detail here.

[0108] As shown in Figures 2 and 5, in some embodiments, a force sensor is installed on only one wheel of the vehicle (e.g., the left front wheel), while the other wheels do not have force sensors installed. The purpose of this embodiment is to achieve effective control and monitoring of the wheel without a force sensor (hereinafter referred to as the "force sensor wheel") using data from a single force sensor.

[0109] A force sensor is installed on one of the four wheels, while the other three wheels do not have force sensors. That is, the force sensorless wheel control method based on a single force sensor is as follows:

[0110] Step S1: Determine whether the conditions for triggering contact calculation are met;

[0111] Step S2: If the conditions are met, proceed with the following steps:

[0112] Step S201: Obtain vehicle parameter information, including the front and rear force distribution ratio, which affects the wear difference between the front and rear brake pads;

[0113] Step S202: Perform contact calculation based on the obtained vehicle parameter information and motor current;

[0114] Step S203: Calculate the piston position based on the motor angle;

[0115] Step S204: Using the clamping force and piston position information of the force sensor wheel, as well as the piston position information of the current wheel, perform stiffness fitting to obtain the estimated clamping force;

[0116] Step S205: Identify the friction torque required for friction compensation control based on motor current, motor speed, and estimated clamping force;

[0117] Step S206: Determine whether a clamping / releasing command has been received from the upper control system. If received, execute the corresponding command based on the estimated clamping force and piston position. If not received, do not perform the clamping / releasing action.

[0118] Step S3: If the conditions are not met, proceed with the following steps:

[0119] Step 301: Calculate the piston position based on the motor angle;

[0120] Step 302: Using the clamping force and piston position information of the force sensor wheel, as well as the piston position information of the current wheel, perform stiffness fitting to obtain the estimated clamping force;

[0121] Step 303: Identify the friction torque required for friction compensation control based on motor current, motor speed, and estimated clamping force;

[0122] Step 304: Determine whether a clamping / releasing command has been received from the upper control system;

[0123] If received, execute the corresponding command based on the estimated clamping force and piston position;

[0124] If not received, the clamping / releasing action will not be performed.

[0125] In this embodiment, one wheel (e.g., the left front wheel) is specifically chosen as the mounting location for the force sensor, while the other three wheels are not equipped with force sensors. The core objective of this solution is to achieve effective control and precise monitoring of all wheels (especially those "force sensor wheels" without sensors) using data from this single force sensor. The detailed implementation process is as follows:

[0126] Trigger condition evaluation:

[0127] First, the system needs to determine whether the current state meets the conditions for triggering the contact calculation. These conditions may involve changes in vehicle speed, braking system status, or motor current.

[0128] If the trigger condition is met, the system will execute the following steps:

[0129] Vehicle parameter acquisition: Collect key vehicle parameters, such as the front-to-rear force distribution ratio, which are crucial for understanding the wear difference between the front and rear brake pads during braking.

[0130] Contact calculation: Combining the acquired vehicle parameters with real-time motor current data, contact calculation is performed to preliminarily estimate the contact state of the brake pads and the possible clamping force range.

[0131] Piston position calculation: Based on motor angle information, accurately calculate the piston position of all wheels (including wheels with force sensors and wheels without force sensors).

[0132] Stiffness fitting and clamping force estimation: Using the actual clamping force and piston position information of the force sensor wheel, combined with the piston position information of the current unforced sensor wheel, the data is input into the preset stiffness fitting model to perform stiffness fitting calculation and estimate the clamping force of the unforced sensor wheel.

[0133] Friction identification: Identify the friction torque required for friction compensation control based on motor current, motor speed, and estimated clamping force.

[0134] Command Response: Determines whether a clamping / releasing command has been received from the upper control system. If received, the corresponding clamping or releasing action is precisely executed based on the estimated clamping force and piston position information; if no command is received, the current state remains unchanged.

[0135] Execution flow when the triggering condition is not met

[0136] If the current state does not meet the conditions for triggering contact calculation, the system will simplify the process and directly execute the following steps:

[0137] Piston position calculation: Also based on motor angle information, the piston position of all wheels is calculated.

[0138] Stiffness fitting and clamping force estimation: Similar to the trigger condition method, but no additional contact calculation is required. Stiffness fitting is performed directly using the current data to estimate the clamping force of the powerless sensor wheel.

[0139] Friction identification: Identify the friction torque required for friction compensation control based on motor current, motor speed, and estimated clamping force.

[0140] Command Response: Similarly, check and respond to commands from the upper control system, and execute the corresponding clamping / releasing action or maintain the status quo.

[0141] This embodiment significantly reduces hardware costs by installing a force sensor on only one wheel, while simultaneously achieving adaptability to the entire vehicle's enhanced system. This method can adapt to different vehicle parameters and driving conditions, improving the system's adaptability and flexibility by acquiring vehicle parameter information (such as the front-to-rear force distribution ratio) and performing corresponding calculations and adjustments.

[0142] Furthermore, by combining data from the wheel with the force sensor with information such as motor current and piston position, stiffness fitting is performed to estimate the clamping force of the wheel without the force sensor. Then, based on the motor current, motor speed, and estimated clamping force, the friction torque required for friction compensation control is identified. This achieves precise control of the wheel without the force sensor, improving the overall performance and safety of the braking system.

[0143] This method can determine in real time whether a clamping / releasing command has been received from the upper control system, and quickly execute the corresponding command based on the estimated clamping force and piston position, ensuring the rapid response and reliability of the braking system. Furthermore, by monitoring and estimating the wheel clamping force in real time, potential problems in the braking system, such as brake pad wear, can be detected promptly, thus helping to optimize maintenance plans and extend the service life of the braking system.

[0144] This embodiment achieves effective control and monitoring of wheels without force sensors using a single force sensor, reducing costs and improving the reliability and safety of the braking system. Simultaneously, this method combines vehicle parameters and motor status information, improving the accuracy of clamping force estimation and providing strong support for intelligent control of the vehicle braking system.

[0145] As shown in Figures 3 and 6, in some embodiments, force sensors are installed on two of the four wheels. The method for controlling a wheel without force sensors based on a single force sensor installed on a vehicle wheel is as follows:

[0146] a) Determine whether the conditions for triggering contact calculation are met;

[0147] b): If the conditions for triggering contact calculation are met, then perform the following steps:

[0148] Step S401: Perform contact calculations based on motor current;

[0149] Step S402: Calculate the piston position based on the motor angle;

[0150] Step S403: Perform stiffness fitting using the clamping force and piston position information of the wheel with force sensor and the piston position information of the wheel without force sensor to obtain the estimated clamping force;

[0151] Step S404: Identify the friction torque required for friction compensation control based on motor current, motor speed, and estimated clamping force;

[0152] Step S405: Determine whether a clamping / releasing command has been received from the upper control system;

[0153] If so, execute the corresponding clamping / releasing command based on the estimated clamping force and piston position;

[0154] If not, then no clamping / releasing action will be performed;

[0155] c) If the conditions for triggering contact calculation are not met, then perform the following steps:

[0156] Step S501: Calculate the piston position directly based on the motor angle;

[0157] Step S502: Similarly, stiffness fitting is performed using the clamping force and piston position information of the wheel with force sensor and the piston position information of the wheel without force sensor to obtain the estimated clamping force;

[0158] Step S503: Identify the friction torque required for friction compensation control based on motor current, motor speed, and estimated clamping force;

[0159] Step S504: Determine whether a clamping / releasing command has been received from the upper control system;

[0160] If so, execute the corresponding clamping / releasing command based on the estimated clamping force and piston position;

[0161] If not, the clamping / releasing action will not be performed.

[0162] This embodiment proposes a method for controlling wheel control without force sensors, based on installing two force sensors on only two vehicle wheels. This method aims to achieve effective control and monitoring of wheel control without force sensors by installing force sensors on only two wheels of the vehicle. The specific implementation process is as follows:

[0163] Force sensor installation: Force sensors are installed on the left front wheel and right rear wheel of the vehicle, respectively; no force sensors are installed on the other wheels. These two force sensors are configured to measure the clamping force of the wheels and provide data support for subsequent contact calculations and stiffness fitting.

[0164] Trigger Condition Determination: The system continuously monitors the vehicle's status to determine whether the conditions for triggering the contact calculation are met. These conditions may include whether the vehicle speed exceeds a certain threshold, whether the braking system is activated, and whether the motor current changes. If the conditions are met, the system proceeds to the next step; otherwise, it directly performs piston position calculation.

[0165] Contact calculation and piston position calculation: When the triggering conditions are met, the system first performs contact calculations based on the motor current to estimate the contact state of the brake pads and the possible clamping force range. Then, it calculates the piston positions of the force sensor wheel and the non-force sensor wheel based on the motor angle.

[0166] Stiffness Fitting and Clamping Force Estimation: The system uses clamping force information and piston position information from the wheel with force sensor, as well as piston position information from the wheel without force sensor, to perform stiffness fitting. Through stiffness fitting calculation, the system obtains the estimated clamping force of the wheel without force sensor. This estimated clamping force is set for subsequent control and monitoring.

[0167] Friction identification: Identify the friction torque required for friction compensation control based on motor current, motor speed, and estimated clamping force.

[0168] Piston position calculation and stiffness fitting: If the triggering condition is not met, the system first calculates the piston position based on the motor angle. Then, stiffness fitting is performed using the clamping force and piston position information of the force sensor wheel and the piston position information of the forceless sensor wheel to obtain the estimated clamping force of the forceless sensor wheel. Finally, the friction torque required for friction compensation control is identified based on the motor current, motor speed, and estimated clamping force.

[0169] Execute clamping / release commands: The system determines and executes clamping / release commands from the upper-level control system. Based on the estimated clamping force and piston position, the system controls the clamping or releasing action of the wheel to achieve actual control over the wheel clamping force.

[0170] This method uses motor current and vehicle parameter information for contact calculations, accurately estimating the contact state of the brake pads and the possible clamping force range. This provides crucial data support for subsequent stiffness fitting. By utilizing the clamping force and piston position information of the wheel with a force sensor, and the piston position information of the wheel without a force sensor, stiffness fitting can be performed to obtain the estimated clamping force of the wheel without a force sensor. Furthermore, based on the motor current, motor speed, and estimated clamping force, the frictional torque required for friction compensation control can be identified. This method effectively solves the problem of the inability to directly measure the clamping force of the wheel without a force sensor.

[0171] This embodiment significantly reduces system complexity and cost by installing force sensors only on two wheels of the vehicle. This makes the method more economical and feasible in practical applications. Through precise contact calculation and stiffness fitting, this method can accurately estimate and control the clamping force on the wheel without force sensors. This ensures the stability and safety of the vehicle braking system.

[0172] In practical applications, this method can be adjusted and optimized according to the specific characteristics of the vehicle and braking system to achieve the best control effect.

[0173] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0174] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

Claims

1. An electromechanical braking system, wherein, include: The control module is configured to send operation commands to control the operation of the braking system; The execution module includes a main execution module and a secondary execution module. The main execution module is equipped with a force sensor and obtains the clamping force through contact recognition, while the secondary execution module obtains the estimated clamping force through contact calculation.

2. The electromechanical braking system according to claim 1, wherein the main execution module comprises: The motor and the speed reduction and torque amplification mechanism are configured to provide clamping or releasing power; The motion conversion mechanism is connected to the motor and the reduction and torque amplification mechanism, and converts the rotational motion of the motor into linear motion. The force sensor is integrated into the motion conversion mechanism and is set to measure the clamping force. A motor position sensor, integrated into the motor or motor controller, is configured to sense the rotation angle of the motor in real time. A current sensor, integrated into the motor or motor controller, is configured to sense the magnitude of the motor current in real time.

3. The electromechanical braking system according to claim 2, wherein, Also includes: The controller, connected to the motor position sensor, current sensor, and force sensor, is configured to receive instructions from the control module and control the rotation of the motor based on the real-time information from the motor position sensor, current sensor, and force sensor to perform clamping or releasing operations.

4. The electromechanical braking system according to claim 1, wherein, The secondary execution module includes a calculation unit, configured to calculate and estimate the clamping force based on the clamping force data and / or other relevant parameters of the main execution module using a preset algorithm, in order to provide redundancy or auxiliary braking.

5. A control method for an electromechanical braking system, wherein force sensors are installed on the wheels of a vehicle; wherein, Its control method includes the following steps: Obtain vehicle parameters and send them to the contact calculation module; perform contact calculations based on the vehicle parameters and motor current; If vehicle parameters are not required, contact calculations are performed based on the motor current. Based on the above contact calculation, the piston position is calculated according to the motor angle information of the powerless sensor wheel to obtain the piston position information of the powerless sensor wheel. Based on the clamping force information of the wheel with force sensor, the motor current and motor angle of the wheel without force sensor, stiffness fitting is performed to determine the estimated clamping force of other wheels. Based on the information obtained from the above steps, perform clamping or releasing.

6. The method according to claim 5, wherein, After obtaining the estimated clamping force through stiffness fitting, and before performing the clamping operation, a friction identification step is also included. In the friction identification step, friction compensation is identified by motor current, motor speed, and estimated clamping force in order to control the required friction torque.

7. The method according to claim 5 or 6, wherein, The stiffness fitting method includes receiving clamping force and piston position information from a force sensor wheel, performing data fitting to obtain a functional relationship between clamping force and piston position, and then calculating an estimated clamping force based on the piston position information of a wheel without a force sensor using this functional relationship.

8. The method according to claim 5, wherein, The methods include: a power sensor wheel control method based on a single force sensor on a vehicle wheel and a power sensor wheel control method based on two force sensors on a vehicle wheel.

9. The method according to claim 8, wherein, The method for controlling a vehicle wheel without a force sensor, based on a single force sensor mounted on the vehicle wheel, is as follows: When a force sensor is installed on one of the wheels of a vehicle, but not on the other wheels, determine whether the conditions for triggering contact calculation are met. If the conditions are met, proceed with the following steps: Obtain vehicle parameter information; perform contact calculations based on the obtained vehicle parameter information and motor current; First, the piston position is calculated based on the motor angle; then, the clamping force of the force sensor wheel, the piston position information, and the piston position information of the corresponding force sensor wheel are used for stiffness fitting to obtain the estimated clamping force. Then, based on the motor current, motor speed, and estimated clamping force, the friction compensation control required is identified. Friction torque; Finally, determine and execute the clamp / release command; If the conditions are not met, proceed with the following steps: First, calculate the piston position based on the motor angle; Then, by using the clamping force and piston position information of the force sensor wheel, as well as the current piston position information of the wheel, stiffness fitting is performed to obtain the estimated clamping force. Then, based on the motor current, motor speed, and estimated clamping force, the friction torque required for friction compensation control is identified. Finally, determine and execute the clamp / release command.

10. The method according to claim 8, wherein, The method for controlling the vehicle wheel without force sensors, based on two force sensors installed on the vehicle wheel, is as follows: Force sensors are installed on two of the vehicle's wheels, while force sensors are not installed on the other wheels; First, determine whether the conditions for triggering contact calculation are met. If the conditions are met, proceed with the following steps: First, perform contact calculations based on the motor current; then, calculate the piston position based on the motor angle. Then, based on the clamping force information and piston position information of the wheel with the force sensor, and the piston position information of the wheel without the force sensor, stiffness fitting is performed to obtain the estimated clamping force. Then, based on the motor current, motor speed, and estimated clamping force, the friction torque required for friction compensation control is identified. Finally, determine and execute the clamp / release command; If the conditions are not met, proceed with the following steps: First, the piston position is calculated based on the motor angle; then, stiffness fitting is performed using the clamping force of the wheel with force sensor and the piston position information, as well as the piston position information of the wheel without force sensor, to obtain the estimated clamping force. Then, based on the motor current, motor speed, and estimated clamping force, the friction torque required for friction compensation control is identified. Finally, determine and execute the clamp / release command.

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