A method and system for brake heat fade compensation and temperature closed-loop control of a by-wire chassis EMB

Abstract

The present application relates to the technical field of drive-by-wire chassis EMB braking, in particular to a drive-by-wire chassis EMB braking heat decay compensation and temperature closed-loop management method and system. The present application collects wheel end multi-measurement point temperature data and weighted fusion, and constructs a temperature monitoring data set; a heat decay model is established based on real-time temperature, braking frequency, braking intensity and heat dissipation rate to quantify the torque decay amplitude; according to the real-time temperature, the control level is divided, the graded closed-loop strategy is matched to dynamically compensate the EMB output torque; when the temperature reaches the limit threshold, the safety degradation mechanism is triggered, the braking torque and the vehicle speed are constrained, the multi-stage alarm is linked and the braking torque is evenly distributed. The present application realizes accurate perception and graded closed-loop management of the braking heat state, and improves the braking heat stability and safety in all working conditions.

Description

Technical Field

[0001] This invention relates to the field of EMB braking technology for drive-by-wire chassis, and in particular to a method and system for thermal fade compensation and closed-loop temperature control of EMB braking for drive-by-wire chassis. Background Technology

[0002] Electromechanical braking (EMB) is a core actuator in fully hydraulic drive-by-wire chassis and is widely used in modern automotive braking systems. Related technologies utilize the coordinated operation of motor drive, mechanical clamping, and friction braking to construct a brake thermal management system. Specifically, this system covers the entire process from temperature monitoring to torque compensation, including key aspects such as temperature acquisition, thermal fade estimation, and torque compensation.

[0003] However, existing EMB brake thermal management methods rely on indirect temperature estimation without real-time, accurate sensing. This can lead to large temperature monitoring errors and an inability to reflect the true degree of thermal fade. Furthermore, the lack of a dynamic torque compensation mechanism results in a continuous decrease in braking torque as temperature rises, increasing braking distance. Additionally, the absence of a temperature-graded closed-loop control logic increases the risk of thermal runaway. The lack of proactive intervention measures for continuous braking heat accumulation accelerates component aging and failure. The lack of linkage between thermal fade compensation and vehicle chassis control can easily cause vehicle posture imbalance. The absence of a forced degradation mechanism at extreme high temperatures and a safety warning mechanism poses a safety hazard of brake failure. Finally, the lack of self-learning calibration of thermal characteristic parameters leads to a decline in compensation accuracy over long-term use, thus affecting driving safety and braking system reliability. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the prior art cannot accurately monitor the temperature of the EMB braking system, dynamically compensate for thermal fade, control the temperature in stages, and provide extreme thermal safety protection.

[0005] To address the aforementioned technical problems, this invention provides a method for EMB brake fade compensation and temperature closed-loop control in a drive-by-wire chassis, comprising: Acquire temperature data from multiple measuring points of the wheel-end braking assembly, and perform weighted fusion of the temperature data from multiple measuring points to construct a wheel-end temperature monitoring dataset; Based on the real-time temperature, braking frequency, braking intensity and heat dissipation rate in the wheel end temperature monitoring dataset, a thermal decay mathematical model is established to quantify the attenuation amplitude of braking torque. Temperature control levels are divided according to the real-time temperature, and a hierarchical closed-loop control strategy is matched for different temperature levels to dynamically compensate the EMB output torque in real time to offset the torque decay caused by thermal degradation. When the real-time temperature reaches the extreme high temperature threshold, the thermal safety degradation mechanism is triggered, which constrains the maximum braking torque and limits the vehicle speed. At the same time, multiple levels of safety alarms are triggered, and the braking torque is evenly distributed to other wheels.

[0006] Preferably, the step of acquiring multi-point temperature data of the wheel-end braking assembly and weightedly fusing the multi-point temperature data to construct a wheel-end temperature monitoring dataset includes: Temperature data are collected in real time at three points: the friction surface of the EMB brake pads of each wheel, the surface of the brake disc, and the stator winding of the motor, using an embedded temperature sensor at the wheel end. The temperature data from the three measuring points are weighted and fused according to a preset weighting coefficient to obtain fused temperature data; Set up a sensor failure degradation mechanism. When a single measuring point sensor fails, the abnormal data is removed and the data is supplemented by interpolation using the fused data from the remaining measuring points and the historical temperature rise curve. When multiple sensors fail, a sensor failure warning is triggered and the system switches to a temperature estimation model for fallback monitoring, thus constructing a wheel-end temperature monitoring dataset.

[0007] Preferably, the step of establishing a thermal fade mathematical model based on the real-time temperature, braking frequency, braking intensity, and heat dissipation rate in the wheel end temperature monitoring dataset, and quantifying the attenuation amplitude of the braking torque, includes: The real-time temperature, braking frequency, braking intensity, and heat dissipation rate in the wheel end temperature monitoring dataset are used as input parameters, and each input parameter is normalized. Based on the normalized parameters, the attenuation amplitude of the braking torque is quantified by the core thermal decay torque calculation formula. The core thermal decay torque calculation formula determines the torque attenuation based on the standard ambient temperature reference braking torque, the basic thermal decay coefficient, the temperature compensation coefficient, the braking frequency correction coefficient, and the braking intensity correction coefficient.

[0008] Preferably, the step of classifying temperature control levels based on the real-time temperature and matching graded closed-loop control strategies for different temperature levels, and dynamically compensating the EMB output torque in real time to offset the torque attenuation caused by thermal decay, includes: Temperature control levels are classified according to the real-time temperature, including normal operating conditions, mild temperature rise conditions, moderate thermal decay conditions, and extreme high temperature conditions. For conditions with slight temperature rise, a small-scale compensation intervention is adopted; For moderate thermal degradation conditions, full-amplitude compensation is adopted and active thermal intervention is initiated; An incremental PID control algorithm is used for real-time dynamic compensation, limiting the increment of torque compensation in a single operation to ensure that the compensation response time meets the preset requirements.

[0009] Preferably, the thermal safety degradation mechanism includes: The maximum clamping force of a single wheel is limited to a preset ratio of the rated maximum value, the maximum speed of the vehicle is limited to a safe speed threshold, and the continuous braking function is disabled.

[0010] Preferably, the linked multi-level security alarm includes: Based on the real-time temperature range, different levels of alarms are triggered, with the alarm levels ranging from low to high including early warning prompts, torque limiting audible and visual alarms, and forced protection alarms.

[0011] Preferably, the method of coordinating with other wheels to evenly distribute braking torque includes: With the objective function of balancing the temperature of each wheel and minimizing the torque deviation, a weighting coefficient is set according to the deviation of the real-time temperature of each wheel from the average real-time temperature of each wheel. This ensures that the wheels with a real-time temperature higher than the average value bear a smaller braking load, while the wheels with a real-time temperature lower than the average value bear a larger braking load, so as to keep the total braking torque of the vehicle constant and the torque distribution deviation between each wheel within a preset range.

[0012] Preferably, the method further includes: When heat accumulates during continuous braking, the active thermal intervention logic is activated. This involves sending a braking request filter parameter correction command to the upper-level driver assistance system to extend the minimum interval between two effective braking actions, lowering the slope of the single braking clamping force, and simultaneously linking the vehicle controller to increase the regenerative braking ratio and turning on the chassis cooling fan to increase the cooling airflow at the wheel ends.

[0013] Preferably, the method further includes: During the torque compensation process, the chassis attitude control is synchronized. The gradient smoothing filtering algorithm is used to convert the torque compensation step signal into a linear gradual signal, and the vehicle attitude signal is collected in real time. When the deviation of the vehicle attitude parameters exceeds the preset threshold, the torque increment adjustment is paused and the torque difference of each wheel is smoothly corrected.

[0014] This invention also provides a drive-by-wire chassis EMB brake fade compensation and temperature closed-loop control system, comprising: The wheel end temperature real-time acquisition module is used to collect temperature data from multiple measurement points of each wheel's EMB brake pads, brake discs, and drive motor in real time through wheel end embedded temperature sensors, and to perform weighted fusion of the multi-measurement point temperature data to construct a wheel end temperature monitoring dataset. The thermal fade torque estimation module is used to establish a thermal fade mathematical model based on the real-time temperature, braking frequency, braking intensity and heat dissipation rate in the wheel end temperature monitoring dataset, and to quantify the attenuation amplitude of the braking torque. The graded temperature closed-loop control module is used to classify temperature control levels according to the real-time temperature and match graded closed-loop control strategies for different temperature levels. The dynamic torque compensation module is used to dynamically compensate the EMB output torque in real time to counteract the torque decay caused by thermal degradation. The extreme thermal safety degradation module is used to trigger the thermal safety degradation mechanism when the real-time temperature reaches the extreme high temperature threshold, thereby constraining the maximum braking torque and limiting the vehicle speed. A multi-level security alarm module is used to link multiple levels of security alarms. When the temperature at the end of a single wheel reaches the extreme high temperature threshold, the extreme thermal safety degradation module also coordinates with other wheels to evenly distribute the braking torque.

[0015] The technical solution of the present invention has the following advantages compared with the prior art: The steerable chassis EMB brake thermal fade compensation and temperature closed-loop control method described in this invention, through real-time acquisition and weighted fusion of temperatures from multiple measuring points at the wheel ends, can accurately perceive the true thermal state of the EMB brake components, overcoming the shortcomings of large errors in indirect estimation; by establishing a thermal fade mathematical model to quantify the torque attenuation amplitude, it can provide an accurate basis for dynamic compensation, effectively solving the problem of continuous torque attenuation at high temperatures; by classifying temperature control levels and matching graded closed-loop control strategies, it can implement differentiated intervention under different thermal conditions, taking into account both conventional braking performance and thermal safety protection; by triggering a thermal safety degradation mechanism at extreme high temperatures and coordinating with other wheels to evenly distribute braking torque, it can provide a safety net under extreme conditions, avoiding the risk of brake failure; in summary, this invention comprehensively improves the thermal stability, braking safety, and functional safety level of the steerable chassis EMB brake system under all temperature conditions. Attached Figure Description

[0016] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a flowchart illustrating the implementation of a method for compensating for brake thermal fade and controlling temperature closed-loop of a drive-by-wire chassis EMB provided by the present invention. Figure 2 This is a schematic diagram of the structure of a drive-by-wire chassis EMB brake thermal fade compensation and temperature closed-loop control system provided by the present invention. Figure 3 This is a schematic diagram of the structure of a drive-by-wire chassis EMB brake thermal fade compensation and temperature closed-loop control system provided in one embodiment of the present invention. Detailed Implementation

[0017] The core of this invention is to provide a method and system for EMB brake thermal fade compensation and temperature closed-loop control in a steerable chassis. By real-time acquisition and weighted fusion of temperatures from multiple wheel-end measuring points, the system accurately senses the braking thermal state. Based on a thermal fade mathematical model, it quantifies the torque attenuation amplitude and combines it with a graded closed-loop control strategy to dynamically compensate the EMB output torque in real time. Simultaneously, under extreme high-temperature conditions, it triggers a thermal safety degradation mechanism and coordinates the balanced distribution of braking torque to each wheel. This effectively solves the technical problems of inaccurate temperature monitoring, lack of dynamic thermal fade compensation, missing graded control, and lack of safety safeguards under extreme conditions in existing technologies. Therefore, it comprehensively improves the thermal stability, braking safety, and functional safety level of the steerable chassis EMB braking system under all temperature conditions.

[0018] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please refer to Figure 1. Figure 1 The flowchart illustrates the implementation of a method for EMB brake fade compensation and temperature closed-loop control in a drive-by-wire chassis provided by this invention; the specific operation steps are as follows: S101: Obtain multi-point temperature data of the wheel-end braking assembly, perform weighted fusion of the multi-point temperature data, and construct a wheel-end temperature monitoring dataset; Real-time temperature monitoring of key heat-generating components in the braking system using wheel-end embedded temperature sensors is a fundamental step in obtaining braking thermal status information. This step aims to construct a temperature monitoring dataset that accurately reflects the wheel-end thermal load, providing reliable data support for subsequent thermal fade determination and compensation. Specifically, temperature sensing elements are installed on core heat-generating components such as brake pads, brake discs, and drive motors at the braking actuator unit. These elements continuously and dynamically collect temperature signals from each measuring point. Since different components exhibit varying heat generation and conduction characteristics during braking, temperature data from a single measuring point cannot comprehensively characterize the overall thermal state of the wheel-end. Therefore, it is necessary to fuse temperature data from multiple measuring points. By assigning appropriate weights to different measuring points, multi-source temperature information is integrated into a comprehensive temperature representation value, thereby constructing a temperature monitoring dataset that reflects the actual thermal load level of the wheel-end. This multi-point weighted fusion method effectively improves the comprehensiveness and accuracy of temperature monitoring, avoiding misjudgments of the thermal state due to localized temperature anomalies or sensor deviations.

[0020] As one implementation method, the brake pad friction surface, the brake disc surface, and the motor stator winding can be selected as three typical measurement points, and each can be assigned a preset weighting coefficient for weighted fusion. At the same time, a sensor failure degradation mechanism can be set up. When the sensor at an individual measurement point fails, the data from the remaining valid measurement points can be combined with the historical temperature rise curve for interpolation to complete the measurement, so as to ensure the continuity and reliability of temperature monitoring.

[0021] This step, through real-time acquisition and weighted fusion of multiple measurement points, enables precise perception of the wheel-end braking thermal state, providing a high-fidelity data foundation for subsequent thermal fade quantification and compensation, thereby significantly improving the response accuracy and robustness of the thermal management system.

[0022] S102: Based on the real-time temperature, braking frequency, braking intensity and heat dissipation rate in the wheel end temperature monitoring dataset, establish a thermal decay mathematical model to quantify the attenuation amplitude of braking torque. Based on the real-time temperature, braking frequency, braking intensity, and heat dissipation rate from the wheel-end temperature monitoring dataset, a thermal decay mathematical model is established to quantify the attenuation amplitude of braking torque. This model focuses on the thermodynamic characteristics of the braking process, comprehensively considering the influence of friction pair temperature rise, braking energy input frequency and intensity, and environmental heat dissipation conditions on the friction coefficient and torque output capability. Specifically, the model input parameters include at least the real-time temperature of the brake disc, the real-time temperature of the brake pads, the temperature of the drive motor, the single braking intensity, the braking frequency per unit time, the environmental heat dissipation wind speed, and the ambient temperature. These parameters collectively characterize the thermal load state and heat dissipation capacity of the braking system. To eliminate the influence of different dimensions and magnitudes on the model calculation, each input parameter can be normalized to map it to a unified numerical range. The normalization formula is as follows: Based on this, by introducing a basic thermal decay coefficient and correction coefficients for temperature, braking frequency, and braking intensity respectively, a calculation relationship for torque attenuation is constructed, thereby converting the degree of thermal decay into a quantifiable torque loss value.

[0023] As one implementation method, the mathematical model can take the following form: the torque attenuation is obtained by multiplying the standard ambient temperature reference braking torque by a factor related to the thermal decay coefficient and multiple correction coefficients. The temperature compensation coefficient, braking frequency correction coefficient, and braking intensity correction coefficient reflect the contribution of different factors to thermal decay, respectively. The values ​​of each correction coefficient are dynamically calculated using real-time collected input parameters, thereby outputting the torque attenuation amplitude under the current operating condition. This model can adapt to a wide temperature range from slight temperature rise to severe thermal decay, providing accurate quantitative basis for subsequent torque compensation.

[0024] By establishing the above-mentioned thermal fade mathematical model, the torque attenuation amplitude during EMB braking is accurately quantified, overcoming the shortcomings of insufficient accuracy in traditional indirect estimation methods. This provides real-time and reliable input for dynamic torque compensation, thereby significantly improving the accuracy and response speed of thermal fade compensation and ensuring the stability of braking performance under all temperature conditions.

[0025] S103: Based on the real-time temperature, the temperature control level is divided, and a graded closed-loop control strategy is matched for different temperature levels to dynamically compensate the EMB output torque in real time to offset the torque decay caused by thermal decay. Classifying the thermal state of the braking system based on real-time temperature and matching corresponding closed-loop control strategies according to different temperature levels is the core means to ensure stable and safe braking performance across the entire temperature range. This method first divides the braking thermal state into multiple control levels with clearly defined temperature boundaries based on real-time temperature values ​​from wheel-end temperature monitoring datasets. Each level corresponds to a specific degree of thermal fade and torque decay characteristics. For different levels, the system employs differentiated closed-loop control logic, including but not limited to the timing of compensation intervention, the upper limit of the compensation amplitude, the rate of compensation response, and whether to link with active thermal management measures. At the mild thermal fade level, only a small amount of torque compensation is performed to offset slight decay and maintain consistent braking response. At the moderate thermal fade level, a full-amplitude dynamic compensation mechanism is activated, and active thermal intervention measures are simultaneously activated to suppress further temperature increases. The compensation process uses a closed-loop adjustment algorithm, using the deviation between the actual output torque and the target torque as a feedback signal to adjust the compensation amount in real time, ensuring that the braking torque remains stable within a preset range under the influence of thermal fade.

[0026] As one implementation method, temperature control levels can be specifically divided into normal operating conditions, mild temperature rise conditions, moderate heat fade conditions, and extreme high-temperature conditions, with corresponding temperature thresholds set. For example, normal operating conditions are defined as temperatures not exceeding 120 degrees Celsius, mild temperature rise conditions are defined as temperatures between 120 and 220 degrees Celsius, moderate heat fade conditions are defined as temperatures between 220 and 350 degrees Celsius, and extreme high-temperature conditions are defined as temperatures exceeding 350 degrees Celsius. The compensation strategy corresponding to each level can be calibrated and adapted according to the brake pad material. The compensation amplitude and response time are both constrained by preset upper limits to prevent overcompensation from causing sudden torque changes.

[0027] This technical step achieves precise and phased intervention in brake fade through a hierarchical closed-loop control strategy. While ensuring normal braking performance, it effectively slows down the escalation of fade and improves the torque output stability and thermal safety margin of the braking system under all temperature conditions.

[0028] S104: When the real-time temperature reaches the extreme high temperature threshold, the thermal safety degradation mechanism is triggered to constrain the maximum braking torque and limit the vehicle speed. At the same time, multiple safety alarms are triggered, and the braking torque is evenly distributed to other wheels.

[0029] When the real-time temperature at the wheel end reaches the preset extreme high-temperature threshold, the system automatically triggers a safety degradation mechanism. The core of this mechanism lies in actively constraining the output capacity of the braking system to avoid the risk of a sudden drop in braking performance or even failure due to sustained high temperatures. Specifically, this degradation mechanism limits the maximum braking torque that a single wheel-end actuator can output and simultaneously limits the vehicle's maximum speed. This ensures that the braking system can still provide predictable and stable braking force under extremely harsh thermal conditions, preventing further temperature runaway or component damage due to excessive torque output. Simultaneously, the system links with multi-level safety alarm modules, issuing different levels of warning signals to the driver or upper-level control system based on the severity of the temperature exceedance, prompting appropriate evasive action. Furthermore, when the temperature at the end of a single wheel reaches the limit threshold, the system does not restrict that wheel in isolation. Instead, it coordinates with other wheels that have not overheated to redistribute the braking torque of the entire vehicle. This allows the high-temperature wheel to reduce its braking load appropriately, while the low-temperature wheel takes on more braking force. In this way, while maintaining the total braking torque of the entire vehicle, it avoids the aggravation of overheating on one side or brake deviation, thus achieving coordinated thermal safety protection at the vehicle level.

[0030] As one implementation method, when the combined temperature of multiple measuring points continuously and stably exceeds 350℃, the system can limit the maximum clamping force of a single wheel to 60% of the rated maximum value and limit the maximum vehicle speed to 60km / h, while disabling continuous braking functions such as automatic parking and hill descent control. The alarm mechanism can be divided into three levels based on the temperature range: Level 1 warning, Level 2 torque limiting, and Level 3 forced protection, corresponding to instrument text prompts, continuous audible and visual alarms, and high-frequency buzzers and constant malfunction indicator lights, respectively, to guide the driver to pull over and cool down in time. In terms of torque balance distribution, the weighting coefficient can be dynamically adjusted according to the real-time temperature of each wheel, so that the braking load of the high-temperature wheel is reduced while the low-temperature wheel makes up for the torque, ensuring that the torque deviation of the four wheels is controlled within the preset range.

[0031] This technology provides a safety net for the braking system under extreme high-temperature conditions through active degradation constraints and multi-round coordinated allocation, effectively avoiding the risk of brake failure caused by thermal fade. At the same time, it takes into account the overall vehicle braking stability and driver controllability, significantly improving the functional safety level of the drive-by-wire chassis under extreme thermal load conditions.

[0032] Based on the above embodiments, in some embodiments, the step of acquiring multi-point temperature data of the wheel-end braking assembly, and weightedly fusing the multi-point temperature data to construct a wheel-end temperature monitoring dataset includes: Temperature data are collected in real time at three points: the friction surface of the EMB brake pads of each wheel, the surface of the brake disc, and the stator winding of the motor, using an embedded temperature sensor at the wheel end. The temperature data from the three measuring points are weighted and fused according to a preset weighting coefficient to obtain fused temperature data; Set up a sensor failure degradation mechanism. When a single measuring point sensor fails, the abnormal data is removed and the data is supplemented by interpolation using the fused data from the remaining measuring points and the historical temperature rise curve. When multiple sensors fail, a sensor failure warning is triggered and the system switches to a temperature estimation model for fallback monitoring, thus constructing a wheel-end temperature monitoring dataset.

[0033] In this embodiment, step S1 achieves accurate acquisition and reliable monitoring of wheel end temperature through the following sub-steps: First, temperature data is collected in real time at three measurement points: the friction surface of the EMB brake pads, the surface of the brake disc, and the stator winding of the motor, using wheel-end embedded temperature sensors. Specifically, high-response temperature sensors (such as thermocouples or thermistors) are embedded at the friction surface of the brake pads, the surface of the brake disc, and the stator winding of the motor at each wheel end. Each sensor uploads its collected temperature signal to the MDC chassis main controller via the vehicle's CANFD bus at millisecond intervals, forming three independent raw temperature data streams.

[0034] Then, the temperature data from the three measuring points are weighted and fused according to preset weighting coefficients. In a specific example, the weighting coefficient for the brake pad friction surface temperature is 0.6, the weighting coefficient for the brake disc surface temperature is 0.3, and the weighting coefficient for the motor stator winding temperature is 0.1. The fused temperature data is obtained by weighted summation, which can comprehensively reflect the core characteristics of the wheel-end braking thermal state.

[0035] Based on this, a sensor fault degradation mechanism is implemented to ensure system robustness. When a single-point sensor fails, the system automatically identifies and removes the abnormal data, uses the fused data from the other two normal measuring points, and interpolates it using the historical temperature rise curve of the wheel end to maintain the continuity and accuracy of the fused temperature data. When two or more measuring points fail simultaneously, the system determines that the sensor group has suffered a severe failure, immediately triggers a sensor fault warning signal, and switches to a temperature estimation model for fallback monitoring. This temperature estimation model calculates the wheel end temperature based on braking frequency, braking intensity, ambient temperature, and heat dissipation rate parameters using thermodynamic formulas, thus providing temperature estimates even in sensor failure scenarios. Finally, the fused or estimated temperature data after the above fault degradation processing is integrated into a wheel end temperature monitoring dataset. This dataset contains the real-time temperature value and confidence level of each wheel end, which is then used by the subsequent thermal decay torque estimation module.

[0036] Through the above-mentioned multi-point weighted fusion and fault degradation mechanism, the accuracy and reliability of wheel end temperature monitoring can be significantly improved. Even when the sensor fails, the continuous output of temperature data can still be maintained, providing a reliable data foundation for thermal decay compensation and temperature closed-loop control, and effectively avoiding compensation misjudgment or lack of safety protection caused by temperature monitoring distortion.

[0037] Based on the above embodiments, in some embodiments, the step of establishing a thermal fade mathematical model based on the real-time temperature, braking frequency, braking intensity, and heat dissipation rate in the wheel end temperature monitoring dataset, and quantifying the attenuation amplitude of the braking torque, includes: The real-time temperature, braking frequency, braking intensity, and heat dissipation rate in the wheel end temperature monitoring dataset are used as input parameters, and each input parameter is normalized. Based on the normalized parameters, the attenuation amplitude of the braking torque is quantified by the core thermal decay torque calculation formula. The core thermal decay torque calculation formula determines the torque attenuation based on the standard ambient temperature reference braking torque, the basic thermal decay coefficient, the temperature compensation coefficient, the braking frequency correction coefficient, and the braking intensity correction coefficient.

[0038] In this embodiment, step S102 precisely quantifies the attenuation amplitude of the braking torque: First, real-time temperature, braking frequency, braking intensity, and heat dissipation rate are obtained as input parameters from the wheel end temperature monitoring dataset. Among them, the real-time temperature is preferably the weighted fusion value of the temperature values ​​of three measuring points: brake pads, brake discs, and drive motors. The braking frequency is the number of braking operations per unit time, the braking intensity is the clamping force or deceleration during a single braking operation, and the heat dissipation rate comprehensively reflects the ambient temperature, wind speed, and wheel end heat dissipation conditions.

[0039] Subsequently, all input parameters are normalized, mapping them to the interval between 0 and 1. The normalization process uses the formula... ,in These are the original parameter values. and These are the minimum and maximum values ​​of the parameter within the preset calibration range, respectively. These are the dimensionless values ​​after normalization. Normalization eliminates the influence of differences in dimensions and numerical ranges of different parameters on subsequent calculations, enabling each parameter to participate in the quantification of thermal decay torque on the same scale.

[0040] Based on normalized real-time temperature, braking frequency, braking intensity, and heat dissipation rate parameters, the attenuation amplitude of the braking torque is quantified using the core thermal decay torque calculation formula. This formula is... ,in This is the torque attenuation. The standard ambient temperature reference braking torque is the rated braking torque output by EMB when the brake disc temperature is at ambient temperature under normal operating conditions (such as T≤120℃). The base thermal fade coefficient reflects the inherent thermal fade characteristics of brake pad and brake disc materials and is obtained through bench testing or vehicle calibration. This is the temperature compensation coefficient, ranging from 0.1 to 0.95. It is determined based on the normalized real-time temperature through a preset mapping relationship or by looking up a table; the higher the temperature, the greater the coefficient. The smaller the value, the more severe the thermal degradation. This is a braking frequency correction factor, calculated based on the normalized braking frequency, for high-frequency braking. Decrease the value to increase the attenuation; This is a braking intensity correction factor, calculated based on the normalized braking intensity during high-intensity braking. The values ​​are reduced to reflect greater torque decay. All correction coefficients are obtained through fitting or calibration with experimental data to ensure the model accurately reflects actual thermal degradation characteristics.

[0041] The formula outputs the torque attenuation. This value is transmitted in real time to the subsequent dynamic torque compensation module and the graded temperature closed-loop control module, serving as the core basis for calculating the compensation torque and adjusting the control strategy. Through the above sub-steps, accurate quantification of torque attenuation from multi-source input parameters is achieved, providing a reliable data foundation for subsequent closed-loop compensation and graded control.

[0042] This specific implementation eliminates the dimensional differences of different physical parameters through normalization processing, and uses the core thermal decay torque calculation formula that includes multi-dimensional correction coefficients such as temperature, frequency, and intensity to achieve accurate quantification of the braking torque decay amplitude. This provides a high-precision input basis for subsequent dynamic compensation and hierarchical control, thereby significantly improving the accuracy and real-time performance of thermal decay compensation.

[0043] Based on the above embodiments, in some embodiments, for the self-learning optimization process of thermal characteristics, the system collects temperature, torque attenuation and compensation data throughout the process. Specifically, the system continuously acquires temperature data from multiple measurement points on the brake pads, brake discs, and drive motor through a real-time wheel-end temperature acquisition module. Simultaneously, a thermal fade torque estimation module records the baseline braking torque, actual output torque, and torque decay amount for each temperature range. A dynamic torque compensation module synchronously stores the compensation coefficient and compensation amount. These data, along with parameters such as ambient temperature, braking frequency, brake pad wear mileage, and usage time, are stored in the vehicle's non-volatile memory, forming a self-learning sample dataset. To ensure the effectiveness of the learning samples, the system executes sample filtering logic during data acquisition: only data from the baseline operating condition at normal temperature and the steady-state braking phase within each temperature range are selected, while data from non-steady-state conditions such as rapid acceleration, steering interference, and sensor malfunctions are removed, and valid samples are marked. The learning timing is set to automatically trigger offline parameter iteration after each vehicle is turned off and allowed to cool to room temperature. The room temperature condition is defined as the wheel-end temperature dropping below 80°C. Parameter iteration is not performed during driving to avoid affecting braking stability.

[0044] During offline iteration, the system calls upon stored valid sample data and uses the least squares method to fit the temperature-torque decay curve. Specifically, with temperature as the independent variable and torque decay as the dependent variable, the optimal fitting parameters are solved by minimizing the sum of squared residuals, thereby iteratively correcting the basic thermal decay coefficient η and the temperature compensation coefficient K_T. The basic thermal decay coefficient η reflects the fundamental influence of brake pad material and wear condition on thermal decay characteristics, while the temperature compensation coefficient K_T characterizes the sensitivity of temperature changes to torque decay, and its value range is dynamically updated with the iteration results.

[0045] After iteration, the updated η and K_T are written into the core parameter tables of the thermal fade torque estimation module and the dynamic torque compensation module, replacing the original fixed parameters for subsequent thermal fade quantification and torque compensation calculations during braking. Furthermore, the system supports offline host computer calibration tools for manual calibration of the learned parameters, and allows reading or writing parameter values ​​through a diagnostic interface, achieving continuous optimization of thermal compensation accuracy throughout the entire lifecycle. This self-learning mechanism can adapt to thermal characteristic drift caused by factors such as brake pad wear, material aging, and environmental changes, ensuring that the compensation model maintains high accuracy over the long term.

[0046] The beneficial effect is that by iteratively correcting the core parameters of the thermal decay model through offline self-learning, the problem of decreased compensation accuracy caused by component aging and wear of fixed parameters is effectively overcome, so that thermal compensation remains stable and reliable throughout the entire life cycle, and the system's adaptability to complex working conditions and braking safety during long-term use is improved.

[0047] Based on the above embodiments, in some embodiments, said dividing temperature control levels according to said real-time temperature, matching hierarchical closed-loop control strategies for different temperature levels, and performing real-time dynamic compensation on EMB output torque to counteract torque attenuation caused by thermal fade comprises: Dividing temperature control levels according to said real-time temperature, wherein said temperature control levels include normal temperature conventional working condition, mild temperature rise working condition, moderate thermal fade working condition and extreme high temperature working condition; For the mild temperature rise working condition, a small-amplitude compensation intervention is adopted; For the moderate thermal fade working condition, full-amplitude compensation is adopted and active thermal intervention is initiated; An incremental PID adjustment algorithm is used for real-time dynamic compensation, and the single torque compensation increment is limited to ensure that the compensation response time meets the preset requirements.

[0048] In this embodiment, step S103 is further refined into the specific implementation of temperature level division and hierarchical compensation control. In one implementation, said dividing temperature control levels according to said real-time temperature and matching hierarchical closed-loop control strategies for different temperature levels in step S103 specifically comprises the following processes: First, temperature control level division is performed according to the real-time fused temperature T in the wheel-end temperature monitoring data set. In one implementation, it is divided into four levels: the normal temperature conventional working condition corresponds to T≤120℃, the mild temperature rise working condition corresponds to 120℃<T≤220℃, the moderate thermal fade working condition corresponds to 220℃<T≤350℃, and the extreme high temperature working condition corresponds to T>350℃. This division is based on the calibration thresholds of brake pad materials, and the thresholds for different materials (such as semi-metallic, ceramic, low-metallic) can be adapted and adjusted according to actual material characteristics during implementation, so as to ensure differentiated intervention under different degrees of thermal fade.

[0049] In one implementation, corresponding compensation strategies are matched for different temperature levels. When it is determined as the mild temperature rise working condition, the system adopts small-amplitude compensation intervention. Specifically, the upper limit of compensation torque may be set to not exceed 15% of the reference torque, and the compensation coefficient K_T is set to 0.1~0.3, so as to counteract slight thermal fade in real time. When it is determined as the moderate thermal fade working condition, the system adopts full-amplitude compensation and synchronously initiates active thermal intervention. In one implementation, the upper limit of compensation torque does not exceed 30% of the reference torque, the compensation coefficient K_T is 0.3~0.9, which is adjusted linearly in real time according to temperature, so as to completely counteract the torque attenuation caused by moderate thermal fade. Specific measures for active thermal intervention include but are not limited to: starting the full-speed cooling fan, extending the minimum interval between two effective brakings, increasing the proportion of regenerative braking, and reducing the rising slope of single braking clamping force, so as to delay the temperature rise rate. The specific values of the above parameters can be set according to the actual vehicle model, brake system configuration and calibration results.

[0050] In one implementation, an incremental PID control algorithm is used for real-time dynamic compensation. The algorithm's input is the deviation between the current torque attenuation ΔT and the target compensation torque, and its output is the single-cycle torque compensation increment. By setting an upper limit for the single-cycle torque compensation increment (e.g., not exceeding 5% of the output torque at the previous moment) and ensuring that the compensation response time meets preset requirements (e.g., not exceeding 20ms), over-compensation is effectively prevented, ensuring the smoothness and stability of the compensation process. A logical closed loop is formed between the temperature level determination, compensation strategy selection, and incremental PID control: the temperature level determination result serves as the basis for selecting the compensation strategy; the compensation upper limit and the active intervention command serve as constraints for incremental PID control; and the smooth compensation torque output after incremental PID control is ultimately transmitted to the EMB wheel-end execution unit, achieving real-time dynamic compensation of the braking torque.

[0051] This specific implementation achieves differentiated and precise compensation for mild and moderate thermal fade conditions through refined temperature level classification and graded compensation strategies. Combined with incremental PID adjustment algorithm, it effectively suppresses torque overshoot, ensuring rapid response and smooth output in the compensation process. Thus, while maintaining constant braking torque, it avoids the risks of vehicle vibration and brake pull, significantly improving the thermal stability and driving safety of the drive-by-wire chassis EMB braking system under all temperature conditions.

[0052] Based on the above embodiments, in some embodiments, the following further includes: When heat accumulates during continuous braking, the active thermal intervention logic is activated. This involves sending a braking request filter parameter correction command to the upper-level driver assistance system to extend the minimum interval between two effective braking actions, lowering the slope of the single braking clamping force, and simultaneously linking the vehicle controller to increase the regenerative braking ratio and turning on the chassis cooling fan to increase the cooling airflow at the wheel ends.

[0053] In this embodiment, when the system determines that it is in a state of continuous braking heat accumulation, it activates active thermal intervention logic. Specifically, the MDC chassis main controller sends a braking request filter parameter correction command to the upper-level driver assistance system, extending the minimum interval between two effective braking actions to reduce heat accumulation caused by high-frequency braking. In one embodiment, this minimum interval can be extended to 150ms. Simultaneously, the rising slope of the single braking clamping force is lowered to slow down the rate of frictional heat generation during clamping. In one embodiment, this rising slope can be reduced from the conventional 800N / ms to 400N / ms. Furthermore, the MDC chassis main controller, in conjunction with the vehicle VCU, requests an increase in the regenerative braking ratio to reduce the frequency and heat generation of mechanical braking. In one embodiment, the regenerative braking ratio can be increased by up to 20%. The system also simultaneously activates the chassis cooling fan to increase the wheel-end cooling airflow and enhance convective cooling. Through these series of active thermal intervention measures, the rate of brake temperature rise is effectively slowed, the aggravation of thermal fade is suppressed, and the stability of braking performance under continuous braking conditions is ensured.

[0054] In one implementation, the aforementioned active thermal intervention logic, through multi-dimensional coordinated adjustment, intervenes simultaneously from four aspects: braking frequency, clamping force rate, regenerative braking distribution, and heat dissipation airflow. This significantly reduces the rate of heat accumulation during continuous braking, preventing the temperature from rapidly rising to the moderate or extreme high temperature range. Consequently, it enhances the thermal safety margin and continuous braking capability of the EMB braking system in high-frequency braking scenarios such as long downhill slopes and congested road conditions.

[0055] Based on the above embodiments, in some embodiments, chassis attitude control is synchronously linked during torque compensation. A gradient smoothing filtering algorithm is used to convert the torque compensation step signal into a linear gradual signal, and the vehicle attitude signal is collected in real time. When the deviation of the vehicle attitude parameters exceeds the preset threshold, the torque increment adjustment is paused and the torque difference of each wheel is smoothly corrected.

[0056] In this embodiment, the specific implementation of the synchronous linkage chassis attitude control during the torque compensation process is as follows: The input sources for this step are the torque compensation step signal output by the dynamic torque compensation module and the real-time acquired vehicle attitude sensor signals. The processing first employs a gradient smoothing filtering algorithm combining first-order inertial filtering and linear gradient interpolation to convert the torque compensation step signal into a linearly gradual signal. First-order inertial filtering suppresses high-frequency noise, while linear gradient interpolation breaks down the torque step change within a preset time period into multiple gradual outputs, ensuring that the rate of change of torque in a single instance does not exceed a preset threshold, thus smoothing the step signal into a continuously gradual signal. Simultaneously, the system acquires real-time vehicle yaw rate, pitch angle, and lateral acceleration signals, provided by the chassis attitude sensors. During processing, when the yaw rate deviation exceeds a preset limit or the pitch acceleration exceeds a preset limit, the system pauses torque increment adjustment and instead performs a smooth correction of the four-wheel torque difference. This correction is based on the current four-wheel torque output difference and dynamically adjusts the torque distribution of each wheel using a gradient smoothing filtering algorithm, gradually converging the four-wheel torque difference within an acceptable range. The output is a smoothed torque compensation command and a corrected four-wheel torque difference signal. This signal is synchronously transmitted to the EMB wheel-end execution unit of each wheel and the chassis attitude coordination module to ensure that the torque compensation process is coordinated with the vehicle body attitude stability.

[0057] In one implementation, to balance smoothness and response speed, linear gradient interpolation can decompose a torque step change within 10 milliseconds into 5 gradual outputs, with the rate of change of torque in a single output not exceeding 3% every 10 milliseconds. The specific limits of the above attitude parameters can be calibrated according to the vehicle model and chassis tuning characteristics. For example, the yaw rate deviation limit can be set to 0.5° / s, and the pitch acceleration limit can be set to 0.3m / s². When any parameter exceeds the limit, the pause and correction logic is triggered.

[0058] Through the above processing, the torque compensation step signal is transformed into a linearly gradual signal, effectively avoiding vehicle vibration and veer issues caused by sudden torque changes. This specific implementation introduces a gradient smoothing filtering algorithm combining first-order inertial filtering with linear gradient interpolation, and incorporates a pause and correction mechanism for real-time attitude feedback. This achieves coordinated control of torque compensation and chassis attitude, significantly improving the smoothness of braking and driving stability, and avoiding the risk of vehicle vibration and veer due to sudden torque changes.

[0059] Based on the above embodiments, in some embodiments, the thermal safety degradation mechanism includes: The maximum clamping force of a single wheel is limited to a preset ratio of the rated maximum value, the maximum speed of the vehicle is limited to a safe speed threshold, and the continuous braking function is disabled.

[0060] In this embodiment, the specific implementation of the extreme high-temperature thermal safety degradation mechanism involved in step S104 is as follows: The system uses embedded temperature sensors at the wheel ends to collect real-time temperature data from multiple measurement points on the brake pads, brake discs, and drive motor. This data is then weighted and fused to form a wheel end temperature monitoring dataset. When the fused temperature value in this dataset consistently exceeds the extreme high-temperature threshold and the stabilization time reaches a preset duration, the system determines that it has entered an extreme high-temperature operating condition. After eliminating transient temperature interference, it automatically triggers a thermal safety degradation mechanism. In one embodiment, the extreme high-temperature threshold can be set to 350°C, and the stabilization time can be set to 5 seconds.

[0061] The degradation mechanism is implemented by the MDC chassis main controller, which outputs control commands to the EMB wheel-end actuators of each wheel and the vehicle VCU controller according to the preset degradation strategy. Regarding torque constraints, the system limits the maximum clamping force of a single wheel to a preset percentage of its rated maximum value, thereby preventing further attenuation of braking torque or thermal failure of mechanical components due to sustained high temperatures. In one embodiment, this preset percentage can be 60%.

[0062] Regarding speed limiting, the system sends a speed limit command to the VCU, restricting the vehicle's maximum speed to a safe speed threshold. The VCU then adjusts the output power of the drive motor accordingly to ensure the vehicle cannot exceed this safe speed. In one implementation, this safe speed threshold can be 60 km / h.

[0063] Regarding function disabling, the system automatically disables the automatic parking function and the hill descent control continuous braking function to prevent further heat accumulation due to continuous or frequent braking under high temperature conditions, which could exacerbate the risk of thermal runaway. The above degradation measures are implemented simultaneously, forming a mandatory constraint on the braking system and the overall vehicle operating status.

[0064] Simultaneously, the system links with multi-level safety alarm modules, outputting alarm signals of different levels according to the temperature range. In one implementation, when the temperature is within the first temperature range, a level one warning is triggered, with the instrument displaying a text prompt and emitting a low-frequency buzzer; when the temperature is within the second temperature range, a level two torque limiting alarm is triggered, with continuous audible and visual alarms and real-time torque output limitation; when the temperature exceeds the extreme high-temperature threshold, a level three forced protection alarm is triggered, with the brake malfunction light constantly illuminated and a high-frequency buzzer sounding, prompting the driver to immediately pull over and allow the vehicle to cool down. In one implementation, the first temperature range can be 280℃ to 350℃, the second temperature range can be 320℃ to 350℃, and the extreme high-temperature threshold can be 350℃.

[0065] The degradation mechanism exits when the wheel-end temperature drops below a safe temperature threshold for a preset duration without any trend of temperature resurgence. In this case, the system automatically de-degrades and issues alarms, resuming the normal braking control strategy. In one implementation, the preset duration can be 60 seconds, and the safe temperature threshold can be 220°C.

[0066] The above implementation methods provide proactive protection against the risk of brake thermal failure under extreme high-temperature conditions. Through precise threshold determination and multi-dimensional degradation measures, the risk of brake failure caused by a sudden drop in braking torque under extreme high temperatures is effectively prevented. Simultaneously, speed limits and function disabling prevent further heat accumulation, significantly improving the safety and reliability of the drive-by-wire chassis EMB braking system under extreme conditions.

[0067] Based on the above embodiments, in some embodiments, the linked multi-level security alarm includes: Based on the real-time temperature range, different levels of alarms are triggered, with the alarm levels ranging from low to high including early warning prompts, torque limiting audible and visual alarms, and forced protection alarms.

[0068] In this embodiment, the multi-level safety alarm mechanism involved in step S104 is based on real-time wheel end temperature monitoring data, triggering differentiated alarms and protective measures according to different ranges of real-time temperature. Specifically, when the multi-point fused temperature data output by the real-time wheel end temperature acquisition module is within the first preset temperature range, the system determines that it has entered a first-level warning state. At this time, a text prompt message is displayed on the instrument panel, and a low-frequency buzzer alarm is triggered to remind the driver to pay attention to the current thermal state of the braking system, but no active limitation is made on the braking torque output. For example, in one embodiment, the first preset temperature range can be 280°C to 350°C. When the real-time temperature further rises to the second preset temperature range, the system triggers a second-level torque limiting state. At this time, in addition to continuously issuing audible and visual alarms, the active torque limiting logic is also activated. That is, the dynamic torque compensation module calculates and limits the maximum clamping force of a single wheel in real time according to the current temperature to ensure that the output torque does not exceed a specific proportion of the rated maximum value, thereby preventing the braking performance from dropping sharply due to excessive attenuation of braking torque caused by continuous temperature rise. For example, in one embodiment, the second preset temperature range can be 320°C to 350°C. When the real-time temperature exceeds the extreme high-temperature threshold, the system triggers a level three forced protection state. At this time, the instrument malfunction indicator light remains on, and a high-frequency audible and visual alarm is issued. Simultaneously, continuous braking functions are forcibly restricted, such as disabling automatic parking, hill descent control, and other functions requiring continuous braking intervention, and the driver is prompted to immediately pull over to allow the vehicle to cool down. For example, in one embodiment, the extreme high-temperature threshold can be 350°C.

[0069] In one implementation, the triggering conditions for the aforementioned multi-level alarms are all based on the fusion temperature of multiple measurement points continuously and stably exceeding a threshold for a certain period of time to eliminate instantaneous temperature interference and ensure the accuracy and reliability of the alarms. For example, this continuous stabilization time can be 5 seconds. Through this hierarchical alarm mechanism, the system can provide gradient safety intervention as the temperature gradually rises, avoiding premature intervention that could affect normal braking performance, while providing forced protection under extreme high temperatures, effectively preventing the risk of brake thermal failure.

[0070] In one implementation, by establishing a multi-level alarm and protection strategy that precisely corresponds to the temperature range, a gradient safety control from early warning prompts to torque limiting and then to forced protection is achieved. This significantly improves driving safety under extreme high-temperature conditions while ensuring braking performance, and avoids the problems of insufficient protection or excessive intervention caused by single threshold alarms.

[0071] Based on the above embodiments, in some embodiments, the coordinated and balanced distribution of braking torque to other wheels includes: With the objective function of balancing the temperature of each wheel and minimizing the torque deviation, a weighting coefficient is set according to the deviation of the real-time temperature of each wheel from the average real-time temperature of each wheel. This ensures that the wheels with a real-time temperature higher than the average value bear a smaller braking load, while the wheels with a real-time temperature lower than the average value bear a larger braking load, so as to keep the total braking torque of the vehicle constant and the torque distribution deviation between each wheel within a preset range.

[0072] In this embodiment, when the wheel end temperature reaches the extreme high temperature threshold, the system triggers the thermal safety degradation mechanism and simultaneously initiates a wheel braking torque equalization distribution process. The input sources for this process are multi-point fused temperature data of the brake pads, brake discs, and drive motors of each wheel uploaded by the real-time wheel end temperature acquisition module, as well as the actual braking torque values ​​output by the current EMB execution units of each wheel and the total required braking torque issued by the vehicle controller. The core of the processing action is to use the equalization of wheel temperatures and the minimization of torque deviation as the objective function, dynamically setting weight coefficients based on the real-time temperature of each wheel.

[0073] Specifically, in one implementation, the system first calculates the average current fusion temperature of each wheel. Then, for each wheel, the weighting coefficient is adjusted according to the degree of deviation between its temperature and the average temperature: for wheel ends with temperatures higher than the average, their weighting coefficient is lowered by a preset amount, with the reduction increasing as the temperature rises; for wheel ends with temperatures lower than the average, their weighting coefficient is correspondingly increased, with the increase matching the total decrease, ensuring that the sum of the weighting coefficients of all wheel ends is 1. For example, in one implementation, the weighting coefficient of wheel ends with temperatures higher than the average is lowered by 0.1 to 0.3. Subsequently, the system multiplies the total required braking torque of the entire vehicle by the weighting coefficient of each wheel to obtain the target distributed torque for each wheel. During the distribution process, the system monitors the deviation between the actual output torque of each wheel and the target distributed torque in real time, and ensures that the torque distribution deviation between each wheel is within a preset range through closed-loop adjustment. For example, in one implementation, the torque distribution deviation between each wheel does not exceed 8%, that is, the ratio of the difference between the maximum and minimum distributed torque to the average distributed torque is controlled within 8%. The output is a balanced distribution of braking torque commands for each wheel. These commands are sent directly to the EMB wheel-end execution units of each wheel, causing the high-temperature wheels to reduce their braking load and the low-temperature wheels to moderately compensate for the torque. This ensures that the total braking torque of the vehicle remains constant, preventing brake failure caused by continuous overheating of a single wheel, while maintaining the braking performance and driving stability of the entire vehicle. In one embodiment, the extreme high-temperature threshold can be 350°C.

[0074] In one implementation, through the aforementioned torque equalization distribution mechanism, the system achieves a reasonable redistribution of heat load under extreme high-temperature conditions, effectively suppressing the risk of single-wheel thermal runaway and improving the reliability and robustness of thermal safety protection under all operating conditions.

[0075] like Figure 2 The present invention also provides a drive-by-wire chassis EMB brake thermal fade compensation and temperature closed-loop control system, comprising: The wheel end temperature real-time acquisition module is used to collect temperature data from multiple measurement points of each wheel's EMB brake pads, brake discs, and drive motor in real time through wheel end embedded temperature sensors, and to perform weighted fusion of the multi-measurement point temperature data to construct a wheel end temperature monitoring dataset. The thermal fade torque estimation module is used to establish a thermal fade mathematical model based on the real-time temperature, braking frequency, braking intensity and heat dissipation rate in the wheel end temperature monitoring dataset, and to quantify the attenuation amplitude of the braking torque. The graded temperature closed-loop control module is used to classify temperature control levels according to the real-time temperature and match graded closed-loop control strategies for different temperature levels. The dynamic torque compensation module is used to dynamically compensate the EMB output torque in real time to counteract the torque decay caused by thermal degradation. The extreme thermal safety degradation module is used to trigger the thermal safety degradation mechanism when the real-time temperature reaches the extreme high temperature threshold, thereby constraining the maximum braking torque and limiting the vehicle speed. A multi-level security alarm module is used to link multiple levels of security alarms. When the temperature at the end of a single wheel reaches the extreme high temperature threshold, the extreme thermal safety degradation module also coordinates with other wheels to evenly distribute the braking torque.

[0076] Based on the above embodiments, in some embodiments, the wheel end temperature real-time acquisition module collects temperature data from three measuring points—the friction surface of the EMB brake pads of each wheel, the surface of the brake disc, and the stator winding of the motor—in real time using an embedded temperature sensor at the wheel end. The temperature data from the three measuring points are weighted and fused according to a preset weighting coefficient to obtain fused temperature data. The wheel end temperature real-time acquisition module also has a built-in sensor fault degradation unit, which is used to remove abnormal data when a single measuring point sensor fails and use the fused data from the remaining measuring points combined with historical temperature rise curves for interpolation to complete the data. When multiple measuring points fail, a sensor fault warning is triggered and the system switches to a temperature estimation model for fallback monitoring.

[0077] Based on the above embodiments, in some embodiments, the thermal decay torque estimation module includes a parameter normalization unit and a decay calculation unit. The parameter normalization unit is used to normalize the real-time temperature, braking frequency, braking intensity, and heat dissipation rate as input parameters. The decay calculation unit is used to quantify the decay amplitude of the braking torque based on the normalized parameters using the core thermal decay torque calculation formula. The formula determines the torque decay based on the standard ambient temperature reference braking torque, the basic thermal decay coefficient, the temperature compensation coefficient, the braking frequency correction coefficient, and the braking intensity correction coefficient.

[0078] Based on the above embodiments, in some embodiments, the graded temperature closed-loop control module classifies the temperature control levels according to the real-time temperature, including normal operating conditions, mild temperature rise conditions, moderate thermal decay conditions, and extreme high-temperature conditions; for mild temperature rise conditions, a small-amplitude compensation intervention is adopted, and for moderate thermal decay conditions, full-amplitude compensation is adopted and active thermal intervention is initiated; the dynamic torque compensation module adopts an incremental PID adjustment algorithm for real-time dynamic compensation, limits the increment of single torque compensation, and ensures that the compensation response time meets the preset requirements.

[0079] Based on the above embodiments, in some embodiments, the thermal safety degradation mechanism triggered by the extreme thermal safety degradation module includes: limiting the maximum clamping force of a single wheel to a preset proportion of the rated maximum value, limiting the maximum vehicle speed to a safe speed threshold, and disabling continuous braking function; the multi-level safety alarm module triggers alarms of different levels according to the real-time temperature range, and the alarm levels from low to high include early warning prompts, torque limiting audible and visual alarms, and forced protection alarms.

[0080] Based on the above embodiments, in some embodiments, the extreme thermal safety degradation module, in coordination with other wheels, evenly distributes braking torque as follows: taking the temperature balance of each wheel and the minimum torque deviation as the objective function, and setting a weighting coefficient according to the deviation of the real-time temperature of each wheel from the average real-time temperature of each wheel, so that the wheels with real-time temperatures higher than the average value bear a smaller braking load and the wheels with real-time temperatures lower than the average value bear a larger braking load, so as to keep the total braking torque of the vehicle constant and the torque distribution deviation between each wheel within a preset range.

[0081] Based on the above embodiments, in some embodiments, an active thermal intervention linkage module is also included, which is used to activate the active thermal intervention logic when continuous braking heat accumulates. It sends a braking request filter parameter correction instruction to the upper-level driving assistance system to extend the minimum interval between two effective braking, and lowers the slope of the single braking clamping force. At the same time, it links the vehicle controller to increase the regenerative braking ratio and turns on the chassis cooling fan to increase the cooling air volume at the wheel ends.

[0082] Based on the above embodiments, in some embodiments, a chassis attitude coordination module is also included, which is used to synchronously link chassis attitude control during torque compensation. The gradient smoothing filtering algorithm is used to convert the torque compensation step signal into a linear gradual signal, and the vehicle attitude signal is collected in real time. When the deviation of the vehicle attitude parameters exceeds a preset threshold, the torque increment adjustment is paused and the torque difference of each wheel is smoothly corrected.

[0083] Based on the above embodiments, in some embodiments, a thermal characteristic self-learning calibration module is also included, which is used to collect temperature, torque decay and compensation data throughout the process. After the vehicle is turned off and left to cool to room temperature, offline parameter iteration is automatically triggered. The least squares method is used to fit the temperature-torque decay curve, and the core parameters of the thermal decay torque estimation module and the dynamic torque compensation module are iteratively corrected to optimize the thermal compensation accuracy.

[0084] Based on the above embodiments, in some embodiments, it further includes an MDC chassis main controller, EMB wheel-end actuators for each wheel, and a VCU vehicle controller; the MDC chassis main controller, as the core main control unit, establishes bidirectional signal connections with each wheel's EMB wheel-end actuator and the wheel-end temperature real-time acquisition module via the vehicle-mounted CANFD bus; the wheel-end temperature real-time acquisition module unidirectionally transmits multi-point temperature data to the thermal decay torque estimation module; the thermal decay torque estimation module outputs the torque decay quantification result to the graded temperature closed-loop control module and the dynamic torque compensation module; the graded temperature closed-loop control module outputs graded control commands to the active thermal dryer. The system includes a pre-linkage module, the extreme thermal safety degradation module, and the multi-level safety alarm module; the dynamic torque compensation module synchronously transmits the smooth compensation torque signal to the chassis attitude coordination module and the EMB wheel-end execution unit of each wheel; the chassis attitude coordination module feeds back the attitude correction signal to the MDC chassis main controller to form a closed-loop adjustment; the thermal characteristic self-learning calibration module collects full data of temperature, torque, and compensation amount, and after completing parameter iteration, reversely corrects the core parameters of the thermal decay torque estimation module and the dynamic torque compensation module; the extreme thermal safety degradation module links with the multi-level safety alarm module and simultaneously outputs degradation alarm signals to the vehicle instrument panel and the VCU vehicle controller.

[0085] Based on the above embodiments, this embodiment provides a specific implementation of a method for EMB brake fade compensation and temperature closed-loop control in a drive-by-wire chassis. This method relies on a complete system architecture, such as... Figure 3As shown, the system includes an MDC chassis main controller, EMB wheel-end actuators for each wheel (e.g., four wheels), a real-time wheel-end temperature acquisition module, a thermal fade torque estimation module, a graded temperature closed-loop control module, a dynamic torque compensation module, an active thermal intervention linkage module, a chassis attitude coordination module, an extreme thermal safety degradation module, a thermal characteristic self-learning calibration module, and a multi-level safety alarm module. The MDC chassis main controller, as the core control unit, establishes a bidirectional signal connection with the EMB wheel-end actuators and the real-time wheel-end temperature acquisition module via the vehicle-mounted CANFD bus. The real-time wheel-end temperature acquisition module unidirectionally transmits multi-point temperature data to the thermal fade torque estimation module. The thermal fade torque estimation module outputs the torque attenuation quantization result to the graded temperature closed-loop control module and the dynamic torque compensation module. The graded temperature closed-loop control module outputs graded control commands to the active thermal intervention linkage module, the extreme thermal safety degradation module, and the multi-level safety alarm module. The dynamic torque compensation module synchronously transmits the smoothing compensation torque signal to the chassis attitude coordination module. The chassis attitude coordination module and the EMB wheel-end actuator are integrated; the chassis attitude coordination module feeds back attitude correction signals to the MDC chassis main controller to form a closed-loop regulation; the thermal characteristic self-learning calibration module collects full data on temperature, torque, and compensation amount, and after parameter iteration, it reversely corrects the core parameters of the thermal decay torque estimation module and the dynamic torque compensation module; the extreme thermal safety degradation module links with multi-level safety alarm modules and simultaneously outputs degradation alarm signals to the vehicle instrument panel and VCU vehicle controller; the energy flow is supplied to each module by the vehicle's low-voltage power supply, and the EMB wheel-end actuator is supplied by the vehicle's high-voltage power supply through the drive circuit, realizing full-domain coordinated control.

[0086] During the data acquisition and preprocessing stage, temperature data from three measuring points—the friction surface of the EMB brake pads on each wheel, the brake disc surface, and the stator winding of the motor—are collected in real time using wheel-end embedded temperature sensors. In one implementation, the temperature data from these three measuring points are weighted and fused according to preset weighting coefficients, such as 0.6, 0.3, and 0.1, to obtain fused temperature data and construct a wheel-end temperature monitoring dataset. A sensor fault degradation mechanism is also implemented: when a single measuring point sensor fails, abnormal data is discarded, and the fused data from the remaining measuring points is interpolated using historical temperature rise curves; when multiple measuring points (e.g., two or more measuring points) fail, a sensor fault warning is triggered, and the system switches to a temperature estimation model for fallback monitoring to ensure the continuity and reliability of the temperature data.

[0087] Based on real-time temperature, braking frequency, braking intensity, and heat dissipation rate from wheel-end temperature monitoring data, a thermal fade mathematical model is established to quantify the attenuation amplitude of braking torque. Input parameters include real-time brake disc temperature, real-time brake pad temperature, motor temperature, single braking intensity, braking frequency per unit time, ambient cooling wind speed, and ambient temperature. All input parameters are normalized to a uniform numerical range (e.g., 0 to 1), using the following normalization formula: The formula for calculating the core thermal decay moment is as follows: ,in This is the torque attenuation. The standard ambient temperature reference braking torque, Based on the basic thermal decay coefficient, This is the temperature compensation coefficient (value range 0.1~0.95). This is the braking frequency correction factor. This is the braking intensity correction coefficient. This model can accurately quantify the degree of torque attenuation based on real-time operating conditions.

[0088] Temperature control levels are determined based on real-time temperature, and the threshold values ​​for each level can be calibrated and adapted according to the brake pad material (e.g., semi-metallic, ceramic, low-metallic, etc.). In one implementation, the specific quantification thresholds are as follows: For normal operating conditions, the temperature does not exceed the first threshold (e.g., 120°C), there is no thermal decay, and no compensation is required; for mild temperature rise conditions, the temperature is greater than the first threshold but not exceeding the second threshold (e.g., 120°C to 220°C), resulting in slight torque decay, requiring small-scale compensation intervention. The upper limit of the compensation torque does not exceed the first preset proportion of the base torque (e.g., 15%), and the compensation coefficient K_T takes the first range (e.g., 0.1 to 0.3); for moderate thermal decay conditions, the temperature is greater than the second threshold but not exceeding the third threshold (e.g., 220°C to 350°C), resulting in significant thermal decay, requiring full-amplitude dynamic compensation and active thermal intervention. The upper limit of the compensation torque does not exceed the second preset proportion of the base torque (e.g., 30%), and the compensation coefficient K_T takes the second range (e.g., 0.3 to 0.9), with real-time linear adjustment based on temperature; for extreme high-temperature conditions, the temperature is greater than the third threshold (e.g., 350°C), posing a serious risk of thermal failure, triggering safety degradation and multi-level alarms. During the dynamic compensation process, an incremental PID control algorithm is adopted. The single torque compensation increment does not exceed the preset proportion of the output torque at the previous moment (e.g., 5%), the compensation response time does not exceed the preset duration (e.g., 20ms), and overcompensation prevention logic is set to prevent overshoot.

[0089] When continuous braking heat accumulates, active thermal intervention logic is activated. This involves sending a braking request filter parameter correction command to the upper-level driver assistance system, extending the minimum interval between two effective braking actions to a preset duration (e.g., 150ms), thus reducing high-frequency braking heat accumulation. Simultaneously, the rate of increase in single braking clamping force is reduced from a conventional value (e.g., from 800N / ms to 400N / ms), slowing the temperature rise rate. The vehicle's VCU is also linked to increase the regenerative braking ratio (in one implementation, this can be increased by up to 20%), reducing the frequency of mechanical braking and heat generation. The chassis cooling fans are also activated simultaneously to increase wheel-end cooling airflow. In one possible implementation, navigation road condition information can be integrated to predict long downhill slopes or congested road sections, activating a thermal protection preparedness mode in advance to further enhance the active cooling effect.

[0090] The torque compensation process is synchronized with chassis attitude control, employing a gradient smoothing filtering algorithm combining first-order inertial filtering and linear gradient interpolation to transform the torque compensation step signal into a linearly gradual signal, ensuring that the rate of change of torque in a single instance does not exceed a preset proportion (e.g., 3% / 10ms). Real-time acquisition of vehicle yaw rate, pitch angle, and lateral acceleration signals is performed, with set limits for yaw rate deviation (e.g., no more than 0.5° / s), pitch acceleration deviation (e.g., no more than 0.3m / s²), and lateral acceleration deviation (e.g., no more than 0.2m / s²). When the yaw rate deviation exceeds a preset threshold (e.g., 0.5° / s) or the pitch acceleration exceeds a preset threshold (e.g., 0.3m / s²), torque increment adjustment is paused, smoothly correcting the torque difference between each wheel, dynamically matching chassis attitude parameters, and completely avoiding braking pull and vehicle vibration issues, ensuring a smooth and stable braking process.

[0091] When the real-time temperature reaches the extreme high-temperature threshold (e.g., greater than 350°C), a thermal safety degradation mechanism is triggered. Specific measures include: limiting the maximum clamping force of a single wheel to a preset percentage (e.g., 60%) of the rated maximum value; limiting the vehicle's maximum speed to a safe speed threshold (e.g., 60 km / h); and disabling automatic parking and hill descent control continuous braking functions. Simultaneously, multiple levels of safety alarms are triggered: Level 1 warning (e.g., 280°C to 350°C) provides instrument panel text prompts and a low-frequency buzzer alarm; Level 2 torque limiting (e.g., 320°C to 350°C) provides continuous audible and visual alarms and actively limits torque output; Level 3 forced protection (e.g., greater than 350°C) provides high-frequency audible and visual alarms, keeps the instrument panel malfunction indicator light on, and forcibly limits continuous braking, prompting the driver to immediately pull over and allow the vehicle to cool down. In one implementation, the degradation recovery condition is that the wheel-end temperature continuously drops below the safe temperature threshold (e.g., 220°C) for a preset duration (e.g., 60 seconds) without any trend of temperature resurgence. The system automatically deactivates the degradation and alarms, restoring the normal braking control strategy.

[0092] When a single wheel overheats, the braking torque is evenly distributed to the other wheels to achieve coordinated thermal protection for the entire vehicle. The torque distribution among the wheels adopts an optimal load distribution algorithm, with the objective function being to achieve temperature balance and minimize torque deviation among the wheels. Weighting coefficients are set according to the real-time temperature of each wheel. The braking load on the high-temperature wheel is reduced, and the torque on the low-temperature wheel is appropriately supplemented to ensure that the total braking torque of the vehicle remains unchanged. In one implementation, the torque distribution deviation between single wheels does not exceed 8%, eliminating the problems of unilateral overheating and brake pull.

[0093] Temperature, torque decay, and compensation data are collected throughout the entire process for self-learning optimization of thermal characteristics. The learning sample data includes baseline braking torque, actual output torque, torque decay, ambient temperature, braking frequency, brake pad wear mileage, and usage time across different temperature ranges. Learning occurs automatically after each vehicle is turned off and allowed to cool to room temperature (in one implementation, room temperature is defined as wheel end temperature dropping below 80°C), triggering offline parameter iteration automatically. Parameter iteration is not performed during driving to avoid affecting braking stability. The temperature-torque decay curve is fitted using the least squares method, iteratively correcting the basic thermal decay coefficient η and temperature compensation coefficient K_T. The parameter range is updated based on brake pad wear and material aging, ensuring continuous and stable thermal compensation accuracy throughout the vehicle's lifespan. Manual calibration of the learned parameters is also supported via offline host computer calibration tools.

[0094] This embodiment, through the aforementioned complete data processing flow, achieves end-to-end thermal safety management, from precise temperature sensing, quantitative modeling of thermal fade, hierarchical closed-loop control, dynamic smoothing compensation, active thermal intervention, chassis attitude coordination, extreme safety degradation to parameter self-learning. It effectively solves the defects of existing technologies, such as inaccurate temperature monitoring, lack of precise thermal fade compensation, lack of hierarchical temperature control, lack of active thermal intervention, lack of extreme safety backup, lack of parameter self-learning, and lack of chassis coordination. It comprehensively improves the thermal stability and functional safety level of the drive-by-wire chassis EMB braking system under all operating conditions.

[0095] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0096] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0097] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0098] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0099] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for compensation of brake fade and closed-loop temperature control in EMB (Electronic Brake-by-Wire) chassis, characterized in that, include: Acquire temperature data from multiple measuring points of the wheel-end braking assembly, and perform weighted fusion of the temperature data from multiple measuring points to construct a wheel-end temperature monitoring dataset; Based on the real-time temperature, braking frequency, braking intensity and heat dissipation rate in the wheel end temperature monitoring dataset, a thermal decay mathematical model is established to quantify the attenuation amplitude of braking torque. Temperature control levels are divided according to the real-time temperature, and a hierarchical closed-loop control strategy is matched for different temperature levels to dynamically compensate the EMB output torque in real time to offset the torque decay caused by thermal degradation. When the real-time temperature reaches the extreme high temperature threshold, the thermal safety degradation mechanism is triggered, which constrains the maximum braking torque and limits the vehicle speed. At the same time, multiple levels of safety alarms are triggered, and the braking torque is evenly distributed to other wheels.

2. The method according to claim 1, characterized in that, The process of acquiring multi-point temperature data of the wheel-end braking assembly, weighting and fusing the multi-point temperature data, and constructing a wheel-end temperature monitoring dataset includes: Temperature data are collected in real time at three points: the friction surface of the EMB brake pads of each wheel, the surface of the brake disc, and the stator winding of the motor, using an embedded temperature sensor at the wheel end. The temperature data from the three measuring points are weighted and fused according to a preset weighting coefficient to obtain fused temperature data; Set up a sensor failure degradation mechanism. When a single measuring point sensor fails, the abnormal data is removed and the data is supplemented by interpolation using the fused data from the remaining measuring points and the historical temperature rise curve. When multiple sensors fail, a sensor failure warning is triggered and the system switches to a temperature estimation model for fallback monitoring, thus constructing a wheel-end temperature monitoring dataset.

3. The method according to claim 1, characterized in that, Based on the real-time temperature, braking frequency, braking intensity, and heat dissipation rate from the wheel end temperature monitoring dataset, a thermal fade mathematical model is established to quantify the attenuation amplitude of the braking torque, including: The real-time temperature, braking frequency, braking intensity, and heat dissipation rate in the wheel end temperature monitoring dataset are used as input parameters, and each input parameter is normalized. Based on the normalized parameters, the attenuation amplitude of the braking torque is quantified by the core thermal decay torque calculation formula. The core thermal decay torque calculation formula determines the torque attenuation based on the standard ambient temperature reference braking torque, the basic thermal decay coefficient, the temperature compensation coefficient, the braking frequency correction coefficient, and the braking intensity correction coefficient.

4. The method according to claim 1, characterized in that, The step of classifying temperature control levels based on the real-time temperature and matching graded closed-loop control strategies for different temperature levels, and dynamically compensating the EMB output torque in real time to offset the torque attenuation caused by thermal decay, includes: Temperature control levels are classified according to the real-time temperature, including normal operating conditions, mild temperature rise conditions, moderate thermal decay conditions, and extreme high temperature conditions. For conditions with slight temperature rise, a small-scale compensation intervention is adopted; For moderate thermal degradation conditions, full-amplitude compensation is adopted and active thermal intervention is initiated; An incremental PID control algorithm is used for real-time dynamic compensation, limiting the increment of torque compensation in a single operation to ensure that the compensation response time meets the preset requirements.

5. The method according to claim 1, characterized in that, The thermal safety degradation mechanism includes: The maximum clamping force of a single wheel is limited to a preset ratio of the rated maximum value, the maximum speed of the vehicle is limited to a safe speed threshold, and the continuous braking function is disabled.

6. The method according to claim 1, characterized in that, The multi-level safety alarm linkage includes: triggering different levels of alarms based on the real-time temperature range, with the alarm levels ranging from low to high including early warning prompts, torque limiting audible and visual alarms, and forced protection alarms.

7. The method according to claim 1, characterized in that, The coordinated and balanced distribution of braking torque to other wheels includes: With the objective function of balancing the temperature of each wheel and minimizing the torque deviation, a weighting coefficient is set according to the deviation of the real-time temperature of each wheel from the average real-time temperature of each wheel. This ensures that wheels with a real-time temperature higher than the average value bear a smaller braking load, while wheels with a real-time temperature lower than the average value bear a larger braking load, so as to keep the total braking torque of the vehicle constant and the torque distribution deviation between each wheel within a preset range.

8. The method according to claim 1, characterized in that, Also includes: When heat accumulates during continuous braking, the active thermal intervention logic is activated. This involves sending a braking request filter parameter correction command to the upper-level driver assistance system to extend the minimum interval between two effective braking actions, lowering the slope of the single braking clamping force, and simultaneously linking the vehicle controller to increase the regenerative braking ratio and turning on the chassis cooling fan to increase the cooling airflow at the wheel ends.

9. The method according to claim 1, characterized in that, Also includes: During the torque compensation process, the chassis attitude control is synchronized. The gradient smoothing filtering algorithm is used to convert the torque compensation step signal into a linear gradual signal, and the vehicle attitude signal is collected in real time. When the deviation of the vehicle attitude parameters exceeds the preset threshold, the torque increment adjustment is paused and the torque difference of each wheel is smoothly corrected.

10. A drive-by-wire chassis EMB brake thermal fade compensation and temperature closed-loop control system, characterized in that, include: The wheel end temperature real-time acquisition module is used to collect temperature data from multiple measurement points of each wheel's EMB brake pads, brake discs, and drive motor in real time through wheel end embedded temperature sensors, and to perform weighted fusion of the multi-measurement point temperature data to construct a wheel end temperature monitoring dataset. The thermal fade torque estimation module is used to establish a thermal fade mathematical model based on the real-time temperature, braking frequency, braking intensity and heat dissipation rate in the wheel end temperature monitoring dataset, and to quantify the attenuation amplitude of the braking torque. The graded temperature closed-loop control module is used to classify temperature control levels according to the real-time temperature and match graded closed-loop control strategies for different temperature levels. The dynamic torque compensation module is used to dynamically compensate the EMB output torque in real time to counteract the torque decay caused by thermal degradation. The extreme thermal safety degradation module is used to trigger the thermal safety degradation mechanism when the real-time temperature reaches the extreme high temperature threshold, thereby constraining the maximum braking torque and limiting the vehicle speed. A multi-level security alarm module is used to link multiple levels of security alarms. When the temperature at the end of a single wheel reaches the extreme high temperature threshold, the extreme thermal safety degradation module also coordinates with other wheels to evenly distribute the braking torque.

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