EMB system clamping force anomaly detection method, response method and detection device

Abstract

The invention discloses an EMB system clamping force abnormity detection method, coping method and detection device, and the method comprises the steps: calculating a first clamping force based on the motor characteristics of an EMB system, and calculating a second clamping force based on the caliper rigidity of the EMB system; calculating a first absolute value of a difference value between the first clamping force and the second clamping force, and calculating a second absolute value of a difference value between a change slope of the first clamping force and a change slope of the second clamping force; if the first absolute value is larger than a preset first absolute value threshold value and / or the second absolute value is larger than a preset second absolute value threshold value, it is judged that the clamping force is abnormal; the first absolute value threshold value and the second absolute value threshold value are calibrated through an EMB clamping force test experiment. According to the method, the EMB system can identify clamping force estimation result abnormity caused by model drifting, mechanical wear or environment change and the like on line, and the braking safety and reliability can be effectively improved.

Description

Technical Field

[0001] This application relates to the field of electromechanical braking system technology, specifically to a method, countermeasure, and detection device for detecting abnormal clamping force in an EMB system. Background Technology

[0002] With the continuous improvement of automotive electronics and intelligence, electromechanical braking systems are gradually replacing traditional hydraulic brakes, using electric motors to drive brake actuators to achieve clamping and releasing. Accurate estimation and control of clamping force is the core of EMB (Electronic Mechanical Brake) systems, directly affecting vehicle braking safety and performance. Currently, EMB systems typically estimate clamping force based on models built from motor characteristics (such as current and rotation angle). However, this single estimation method carries risks: when model parameters drift due to temperature changes, mechanical wear, component aging, etc., the estimated clamping force deviates from the true value, leading to abnormal clamping force estimation results. The EMB system itself cannot detect these abnormalities, potentially resulting in insufficient or excessive braking force, posing safety hazards. Summary of the Invention

[0003] This application provides a method, solution, and detection device for detecting abnormal clamping force in an EMB system, which can solve the technical problem that the clamping force estimation results are abnormal in existing EMB clamping force estimation technologies, and the EMB system itself cannot detect them.

[0004] To achieve the above objectives, in a first aspect, this application provides a method for detecting abnormal clamping force in an EMB system, the method comprising: The first clamping force is calculated based on the motor characteristics of the EMB system, and the second clamping force is calculated based on the caliper rigidity of the EMB system.

[0005] Calculate the first absolute value of the difference between the first clamping force and the second clamping force, and calculate the second absolute value of the difference between the slope of change of the first clamping force and the slope of change of the second clamping force.

[0006] If the first absolute value is greater than a preset first absolute value threshold and / or the second absolute value is greater than a preset second absolute value threshold, then the clamping force is determined to be abnormal; both the first absolute value threshold and the second absolute value threshold are calibrated through EMB clamping force test experiments.

[0007] Furthermore, in one embodiment, the triggering conditions for the EMB system clamping force anomaly detection method include: If the vehicle is stationary and the vehicle braking control system does not receive a braking request signal, the EMB system actively applies a preset clamping force and performs the detection method under this clamping force; the clamping force is preset based on the resistance of the EMB system and the vehicle's subjective vibration test.

[0008] If the vehicle is in motion and the vehicle braking control system receives a braking request signal, the EMB system executes the detection method under the current clamping force.

[0009] Furthermore, in one embodiment, the calculation of the first clamping force based on the motor characteristics of the EMB system includes: The first clamping force is calculated based on the motor current and rotation angle, combined with the pre-calibrated motor torque model and transmission system model; the motor torque model is calibrated according to the motor characteristics, and the transmission system model is calibrated according to the rigidity of the EMB system.

[0010] Furthermore, in one embodiment, the calculation of the second clamping force based on the EMB system caliper rigidity includes: The second clamping force is calculated based on the caliper piston displacement and the equivalent stiffness of the caliper system in the EMB system; the caliper piston displacement is calculated based on the motor rotation angle, the transmission ratio of the EMB system, and the transmission stroke efficiency.

[0011] Secondly, this application provides an anomaly response method for an abnormal clamping force detection method in an EMB system, the method comprising: If an abnormal clamping force is detected, the first out-of-tolerance ratio is calculated based on the first absolute value and the first absolute value threshold.

[0012] The second deviation ratio is calculated based on the second absolute value and the second absolute value threshold.

[0013] The response strategy is determined based on the first deviation ratio and the second deviation ratio.

[0014] Furthermore, in one embodiment, determining the response strategy based on the first deviation ratio and the second deviation ratio includes: If the first out-of-tolerance ratio and / or the second out-of-tolerance ratio are greater than a preset first ratio threshold and less than or equal to a preset second ratio threshold, an alarm strategy is executed.

[0015] If the first excess ratio and / or the second excess ratio are greater than the second ratio threshold, an alarm and braking control strategy is executed.

[0016] Furthermore, in one embodiment, both the first proportional threshold and the second proportional threshold are determined experimentally by measuring the impact of the EMB system clamping force calculation deviation on the vehicle's braking safety.

[0017] Furthermore, in one embodiment, the alarm strategy is to illuminate the braking system fault indicator light and issue an alarm sound.

[0018] Furthermore, in one embodiment, the braking control strategy is to control the vibration of the brake pedal and send a torque limiting request to the vehicle controller.

[0019] Secondly, this application provides an EMB system clamping force abnormality detection device, the device comprising: The first calculation module is used to calculate the first clamping force based on the motor characteristics of the EMB system and the second clamping force based on the caliper rigidity of the EMB system.

[0020] The second calculation module is used to calculate the first absolute value of the difference between the first clamping force and the second clamping force, and also to calculate the second absolute value of the difference between the slope of change of the first clamping force and the slope of change of the second clamping force.

[0021] An anomaly detection module is used to determine that the clamping force is abnormal if the first absolute value is greater than a preset first absolute value threshold and / or the second absolute value is greater than a preset second absolute value threshold; both the first absolute value threshold and the second absolute value threshold are calibrated through EMB clamping force test experiments.

[0022] The beneficial effects of the technical solutions provided in this application include: This application calculates a first clamping force based on the motor characteristics of the EMB system and a second clamping force based on the caliper rigidity of the EMB system. It calculates the first absolute value of the difference between the first and second clamping forces, and the second absolute value of the difference between the slope of change of the first and second clamping forces. If the first absolute value is greater than a preset first absolute value threshold and / or the second absolute value is greater than a preset second absolute value threshold, the clamping force is determined to be abnormal. The first and second clamping forces are obtained through parallel estimation via dual channels of motor characteristics and caliper rigidity. The difference between the first and second clamping forces, and the difference between the slope of change of the first and second clamping forces, are used to determine whether the clamping force is abnormal. This allows the EMB system to identify abnormal clamping force estimation results caused by model drift, mechanical wear, or environmental changes online, effectively improving braking safety and reliability. Attached Figure Description

[0023] Figure 1 This is a flowchart of the EMB system clamping force abnormality detection method according to an embodiment of this application.

[0024] Figure 2 This is a flowchart of an abnormal response method for the EMB system clamping force abnormal detection method in an embodiment of this application.

[0025] Figure 3 This is a block diagram of the EMB system clamping force abnormality detection device according to an embodiment of this application. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0028] In a first aspect, embodiments of this application provide a method for detecting abnormal clamping force in an EMB system.

[0029] In one embodiment, see Figure 1 As shown, the above-mentioned EMB system clamping force abnormality detection method includes: S1. Calculate the first clamping force based on the motor characteristics of the EMB system, and calculate the second clamping force based on the caliper rigidity of the EMB system.

[0030] S2. Calculate the first absolute value of the difference between the first clamping force and the second clamping force, and calculate the second absolute value of the difference between the slope of the change of the first clamping force and the slope of the change of the second clamping force.

[0031] S3. If the first absolute value is greater than the preset first absolute value threshold and / or the second absolute value is greater than the preset second absolute value threshold, then the clamping force is judged to be abnormal. The first absolute value threshold and the second absolute value threshold are both calibrated by EMB clamping force test experiment. In this embodiment, the formula for the first absolute value threshold is: 100 + 20t, where t represents the braking time. In 3 batches of clamping force generating parts (such as brake caliper body, caliper piston, etc.), 10 samples are randomly selected from each batch to conduct clamping force test experiment calibration to obtain constants of 100 and 20. The second absolute value threshold can be 3kN / mm.

[0032] In this embodiment, a dual-channel parallel computing architecture based on "motor characteristics-caliper rigidity" is used to simultaneously obtain the first clamping force and the second clamping force during braking execution, creating natural redundancy between the two in the time domain and in terms of their changing trends. Subsequently, the two calculation results are double-checked for both the difference in the calculation result and the difference in the slope of change. If either check exceeds the corresponding threshold, an anomaly flag is immediately triggered. This mechanism transforms uncertainties such as model drift, mechanical wear, temperature expansion, and changes in lubrication status—factors that a single model cannot perceive—into two residual signals with independent physical mechanisms and uncorrelated error statistics. This achieves online fault self-identification with extremely low false alarm and false negative rates. Since the caliper rigidity channel is almost unaffected by motor parameter drift, and the motor characteristic channel is insensitive to changes in caliper stiffness, the two serve as mutual references and backups, significantly improving the estimation robustness of the system throughout its entire lifecycle and operating conditions. At the same time, the coordinated judgment of the difference and slope dual thresholds can take into account both abrupt faults and gradual degradation, providing timely and reliable health status information for the braking control strategy. Ultimately, without adding additional sensors, it effectively suppresses the risk of insufficient or excessive braking force caused by inaccurate clamping force estimation, ensuring the braking performance and driving safety of the entire vehicle.

[0033] Furthermore, in one embodiment, the triggering conditions for the above-mentioned EMB system clamping force abnormality detection method include: If the vehicle is stationary and the vehicle braking control system does not receive a braking request signal, the EMB system actively applies a preset clamping force and performs the above detection method under this clamping force; wherein, the clamping force is preset based on the resistance of the EMB system and the subjective vibration test of the vehicle.

[0034] If the vehicle is in motion and the vehicle braking control system receives a braking request signal, the EMB system performs the above detection method under the current clamping force.

[0035] In this embodiment, the monitoring logic is triggered in two modes based on the vehicle status: active monitoring and passive monitoring. In active monitoring mode, if the EMB (Electronic Mechanical Brake) system determines that the vehicle is stationary (based on signals such as zero speed, gear in P or N, and handbrake engaged), and the vehicle braking control system has not received a braking request signal, confirming that the current braking request will not affect driving safety (e.g., no emergency braking requirement), the EMB system actively applies a preset, small clamping force and executes the aforementioned detection method under this clamping force. In passive monitoring mode, when the driver presses the brake pedal to issue a braking request during vehicle operation, the vehicle braking control system performs normal braking operation according to the requested braking force, and the EMB system executes the aforementioned detection method under the current clamping force.

[0036] By employing a dual-mode approach of zero-speed self-testing and on-the-go inspection, clamping force health diagnosis is seamlessly integrated into the entire vehicle lifecycle: when stationary, low-load conditions are proactively established using the parking window to avoid impacting driving safety; while driving, real braking requests are utilized to capture intermittent faults and progressive degradation under real load and temperature rise conditions. The two modes complement and verify each other, improving anomaly detection coverage without requiring additional hardware costs; simultaneously, the preset clamping force reference is based on the calibration principle of just overcoming drag torque and ensuring no vibration felt by occupants, taking into account both diagnostic signal-to-noise ratio and NVH (Noise, Vibration and Harshness) experience, ultimately achieving "all-weather, all-condition, self-triggered, zero-perception" online health monitoring, significantly improving the functional safety and braking reliability of the EMB system throughout its entire lifecycle.

[0037] Furthermore, in one embodiment, in step S1 above, the calculation of the first clamping force based on the motor characteristics of the EMB system specifically involves the following steps: The first clamping force is calculated based on the motor current and rotation angle, combined with the pre-calibrated motor torque model and transmission system model. The motor torque model is calibrated according to the motor characteristics, and the transmission system model is calibrated according to the rigidity of the EMB system.

[0038] Furthermore, in one embodiment, in step S1 above, the second clamping force is calculated based on the caliper rigidity of the EMB system. The specific steps are as follows: The second clamping force is calculated based on the caliper piston displacement and the equivalent stiffness of the caliper system in the EMB system; the caliper piston displacement is calculated based on the motor rotation angle, the transmission ratio of the EMB system, and the transmission stroke efficiency.

[0039] The formula for calculating the second clamping force is as follows: (1), in, This indicates the second clamping force. This indicates the equivalent stiffness of the caliper system. This indicates the displacement of the caliper piston.

[0040] Furthermore, in one embodiment, in step S2 above, the method for calculating the slope of the change of the first clamping force is: the difference between the first clamping force at the current moment and the first clamping force at the previous moment, divided by the sampling time interval between the two first clamping forces.

[0041] The method for calculating the slope of the second clamping force change is: the difference between the second clamping force at the current moment and the second clamping force at the previous moment, divided by the sampling time interval between the two second clamping forces.

[0042] Secondly, embodiments of this application provide an abnormal response method for an EMB system clamping force abnormality detection method.

[0043] In one embodiment, see Figure 2 As shown, the abnormal response methods of the above-mentioned EMB system clamping force abnormality detection method include: A1. If an abnormal clamping force is detected, calculate the first out-of-tolerance ratio based on the first absolute value and the first absolute value threshold mentioned above.

[0044] A2. Calculate the second excess ratio based on the second absolute value and the second absolute value threshold mentioned above.

[0045] A3. Determine the response strategy based on the first and second excess ratios mentioned above.

[0046] In this embodiment, a dual-proportional-gradient response strategy is employed to quantify the abstract clamping force anomaly into calibrable first and second out-of-tolerance ratios. This elevates fault response from simple fault reporting and disabling to tiered intervention and flexible degradation. This proportionalized grading mechanism prevents both a one-size-fits-all approach that degrades braking experience and leads to false alarms after service, while ensuring that truly dangerous faults trigger high-level protection within a short timeframe. This achieves a triple effect of controllable risk, acceptable experience, and extended lifespan, significantly improving the functional safety, availability, and customer satisfaction of the EMB system.

[0047] Furthermore, in one embodiment, the formula for calculating the first deviation ratio in step A1 above is: (2), in, Indicates the first percentage of deviations. Indicates the first clamping force. This represents the first absolute value threshold.

[0048] Furthermore, in one embodiment, the formula for calculating the second deviation ratio in step A2 above is: (3), in, This indicates the second percentage of deviations. This represents the slope of the change in the first clamping force. This indicates the slope of the change in the second clamping force. This represents the second absolute value threshold.

[0049] Furthermore, in one embodiment, in step A3 above, the response strategy is determined based on the first deviation ratio and the second deviation ratio. The specific steps are as follows: If the first excess ratio and / or the second excess ratio are greater than the preset first ratio threshold and less than or equal to the preset second ratio threshold, an alarm strategy is executed.

[0050] If the first excess ratio and / or the second excess ratio are greater than the second ratio threshold, an alarm and braking control strategy is executed.

[0051] The first proportional threshold and the second proportional threshold are both determined by experimental calibration of the impact of the clamping force calculation deviation of the EMB system on the braking safety of the whole vehicle. In this embodiment, the first proportional threshold can be 5% and the second proportional threshold can be 15%.

[0052] The alarm strategy mentioned above involves illuminating the brake system fault indicator light and issuing an alarm sound, while the brake control strategy involves controlling the vibration of the brake pedal and sending a torque limit request to the vehicle controller.

[0053] In this embodiment, a tiered response strategy is formulated, specifically: If the first out-of-tolerance ratio and / or the second out-of-tolerance ratio are greater than the preset first ratio threshold and less than or equal to the preset second ratio threshold, an alarm strategy is executed. A command is sent to the instrument cluster via the CAN (Controller Area Network) bus to illuminate a specific brake system fault indicator light (usually yellow / amber). At the same time, a single or continuous warning sound is triggered, which is emitted through the vehicle audio system or a dedicated buzzer.

[0054] If the first out-of-tolerance ratio and / or the second out-of-tolerance ratio exceed the second ratio threshold, all actions of the above alarm strategy are executed. At the same time, the braking control strategy is also executed, sending a command to the brake pedal simulator to drive its internal vibration motor, causing the brake pedal to vibrate at high frequency. This is an extremely intuitive and hard-to-ignore serious warning. Simultaneously, through the vehicle CAN network, a request message to limit braking torque is sent to the vehicle controller or motor controller. This request will forcibly limit the output torque of the drive motor, for example, limiting the torque to less than 50% of the current level or an absolute safety value, thereby effectively preventing acceleration hazards that may be caused by abnormal braking force and forcing the driver to slow down and stop.

[0055] Thirdly, embodiments of this application provide an EMB system clamping force abnormality detection device.

[0056] In one embodiment, see Figure 3 As shown, the above-mentioned EMB system clamping force anomaly detection device includes a first calculation module, a second calculation module, and an anomaly judgment module: The first calculation module is used to calculate the first clamping force based on the motor characteristics of the EMB system and the second clamping force based on the caliper rigidity of the EMB system.

[0057] The second calculation module is used to calculate the first absolute value of the difference between the first clamping force and the second clamping force, and also to calculate the second absolute value of the difference between the slope of change of the first clamping force and the slope of change of the second clamping force.

[0058] An anomaly detection module is used to determine that the clamping force is abnormal if the first absolute value is greater than a preset first absolute value threshold and / or the second absolute value is greater than a preset second absolute value threshold; wherein the first absolute value threshold and the second absolute value threshold are both calibrated through EMB clamping force test experiments.

[0059] This application provides a method, response method and detection device for detecting abnormal clamping force in an EMB system. The core of this method is: triggering an active monitoring mode or a passive monitoring mode based on the vehicle status, performing fault diagnosis through dual-path clamping force estimation and dual-dimensional cross-comparison, and initiating graded alarm and degradation strategies based on the severity of the fault.

[0060] Through a quadruple redundancy architecture of "dual-mode triggering, dual-path estimation, dual-threshold verification, and dual-proportional grading," the slow drift and sudden failures originally hidden in the motor model or mechanical links are transformed into quantifiable, calibrable, and cloud-trackable health indicators. During the stationary parking phase, a "low-load diagnostic condition" is periodically established in an active monitoring mode to complete self-calibration and early fault incubation without the driver's awareness. During the driving phase, real braking requests are used to capture model mismatch and mechanical mutations in real-time in a high-load, high-temperature, and high-dynamic environment, achieving seamless coverage of the entire lifecycle of "zero-speed self-testing + on-the-go inspection."

[0061] The motor characteristic channel and the caliper rigidity channel have independent physical mechanisms and uncorrelated error statistics. They serve as mutual references and backups, eliminating missed detections caused by single-model parameter drift and avoiding false alarms due to environmental disturbances. The dual thresholds of difference and slope cover both abrupt hard faults and gradual aging, providing full coverage of diagnostic windows from millisecond-level impacts to tens of thousands of kilometers of cumulative wear. Once an anomaly is confirmed, the "out-of-tolerance ratio-graded response" strategy is immediately activated: linking instrument panel audible and visual alarms, pedal vibration, torque limiting, and redundant braking channels to form a "perception-decision-execution" closed loop, ensuring that the driver is forcibly guided to a safe state before braking force gaps occur. The entire solution requires no additional sensors; all algorithms run within the existing EMB controller and interact with the vehicle network in real time via the CAN bus, providing high-value data assets for predictive maintenance, quality traceability, and next-generation braking model calibration. Ultimately, this application transforms the traditionally latent defect of "abnormal clamping force estimation" into a "predictable, manageable, and optimizable" online safety asset, significantly reducing after-sales risks and recall costs, comprehensively improving vehicle braking performance, functional safety, and customer satisfaction, and providing a high-confidence braking redundancy foundation for advanced autonomous driving.

[0062] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0063] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0064] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0065] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0066] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0067] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0068] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for detecting abnormal clamping force in an EMB system, characterized in that, The detection method includes: The first clamping force is calculated based on the motor characteristics of the EMB system, and the second clamping force is calculated based on the caliper rigidity of the EMB system. Calculate the first absolute value of the difference between the first clamping force and the second clamping force, and calculate the second absolute value of the difference between the slope of change of the first clamping force and the slope of change of the second clamping force; If the first absolute value is greater than a preset first absolute value threshold and / or the second absolute value is greater than a preset second absolute value threshold, then the clamping force is determined to be abnormal; both the first absolute value threshold and the second absolute value threshold are calibrated through EMB clamping force test experiments.

2. The EMB system clamping force abnormality detection method as described in claim 1, characterized in that, The triggering conditions for the abnormal clamping force detection method of the EMB system include: If the vehicle is stationary and the vehicle braking control system does not receive a braking request signal, the EMB system actively applies a preset clamping force and performs the detection method under this clamping force; the clamping force is preset based on the resistance of the EMB system and the vehicle's subjective vibration test. If the vehicle is in motion and the vehicle braking control system receives a braking request signal, the EMB system executes the detection method under the current clamping force.

3. The EMB system clamping force abnormality detection method as described in claim 1, characterized in that, The calculation of the first clamping force based on the motor characteristics of the EMB system includes: The first clamping force is calculated based on the motor current and rotation angle, combined with the pre-calibrated motor torque model and transmission system model; the motor torque model is calibrated according to the motor characteristics, and the transmission system model is calibrated according to the rigidity of the EMB system.

4. The EMB system clamping force abnormality detection method as described in claim 1, characterized in that, The calculation of the second clamping force for the caliper rigidity based on the EMB system includes: The second clamping force is calculated based on the caliper piston displacement and the equivalent stiffness of the caliper system in the EMB system; the caliper piston displacement is calculated based on the motor rotation angle, the transmission ratio of the EMB system, and the transmission stroke efficiency.

5. An anomaly response method based on the EMB system clamping force anomaly detection method according to any one of claims 1-4, characterized in that, The method includes: If an abnormal clamping force is detected, the first deviation ratio is calculated based on the first absolute value and the first absolute value threshold. Calculate the second deviation ratio based on the second absolute value and the second absolute value threshold; The response strategy is determined based on the first deviation ratio and the second deviation ratio.

6. The EMB system clamping force abnormality detection method as described in claim 5, characterized in that, The step of determining the response strategy based on the first deviation ratio and the second deviation ratio includes: If the first excess ratio and / or the second excess ratio are greater than a preset first ratio threshold and less than or equal to a preset second ratio threshold, an alarm strategy is executed. If the first excess ratio and / or the second excess ratio are greater than the second ratio threshold, an alarm and braking control strategy is executed.

7. The EMB system clamping force abnormality detection method as described in claim 6, characterized in that, The first and second proportional thresholds were both calibrated experimentally based on the impact of the clamping force calculation deviation of the EMB system on the braking safety of the vehicle.

8. The EMB system clamping force abnormality detection method as described in claim 5, characterized in that, The alarm strategy involves illuminating the brake system fault indicator light and emitting an alarm sound.

9. The EMB system clamping force abnormality detection method as described in claim 5, characterized in that, The braking control strategy involves controlling the vibration of the brake pedal and sending a torque limiting request to the vehicle controller.

10. A device for detecting abnormal clamping force in an EMB system, characterized in that, The device includes: The first calculation module is used to calculate the first clamping force based on the motor characteristics of the EMB system and to calculate the second clamping force based on the caliper rigidity of the EMB system. The second calculation module is used to calculate the first absolute value of the difference between the first clamping force and the second clamping force, and also to calculate the second absolute value of the difference between the slope of the change of the first clamping force and the slope of the change of the second clamping force. An anomaly detection module is used to determine that the clamping force is abnormal if the first absolute value is greater than a preset first absolute value threshold and / or the second absolute value is greater than a preset second absolute value threshold; both the first absolute value threshold and the second absolute value threshold are calibrated through EMB clamping force test experiments.

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