Brake pedal shaking amount detection method and system

Abstract

The invention relates to the technical field of part detection, in particular to a brake pedal shaking quantity detection method and system, after a pedal simulation loading angle is fixed, a servo electric cylinder sequentially applies + / -9.8 N force in the side direction of the pedal, and the force control contact and displacement synchronous triggering technology is adopted to accurately collect displacement values on the two sides; and calculating the total shaking quantity and comparing the total shaking quantity with a standard value (such as less than or equal to 4mm) for judgment. The system correspondingly comprises a positioning and fixing device, a transverse loading device, a displacement detection device and a control processing device. According to the invention, full-automatic and high-precision detection and real-time determination of the shaking amount of the pedal are realized, and by means of automatic identification and data binding of the product number, single-piece accurate tracing of the detection data is ensured, and the product quality control level and the production efficiency are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of component testing technology, and in particular to a method and system for detecting brake pedal wobble. Background Technology

[0002] With the rapid development of the automotive industry, the driving comfort of drivers is constantly improving. Currently, the lateral wobble of brake pedal assemblies is not tested before production and shipment. As a result, brake pedal assemblies with excessive wobble are installed in the vehicle, affecting the driver's comfort and causing abnormal noise when pedaling. It is impossible to achieve automatic and real-time detection and judgment of lateral wobble during the pedal production process. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for detecting brake pedal wobble, enabling automatic, accurate, and real-time detection and determination of lateral wobble during pedal production.

[0004] To achieve the above objectives, in a first aspect, the present invention provides a method for detecting brake pedal wobble, comprising the following steps: The pedal assembly to be tested is fixed at the testing station at a simulated vehicle mounting angle. The lateral loading device is controlled to apply a first target detection force in a first direction to the first side of the test pedal, and when the first target detection force is reached, the displacement detection device is triggered to record the first displacement value. The lateral loading device is controlled to apply a second target detection force opposite to the first direction on the second side of the test pedal, and when the second target detection force is reached, the displacement detection device is triggered to record the second displacement value; Based on the first displacement value and the second displacement value, calculate the total lateral sway of the test pedal; The total lateral sway is compared with the preset tolerance upper limit to determine whether the pedal is qualified; After being determined to be unqualified, the method further includes: An NG warning pop-up window appears on the human-machine interface of the industrial control computer, containing the product number, the measured shaking amount, and information on exceeding the standard, and an audible and visual alert is issued. The control panel activates the three-color alarm light at the site, which illuminates red and flashes, and locks the start button except for the release button of the depressurization clamp. Acquire the processing completion signal and associate it with the detection data record of the corresponding test pedal; The method further includes: Before the pedal to be tested is placed, a unique number is obtained by scanning a barcode or RFID reader and then transmitted to the industrial control computer and PLC. The unique number will be used as the current product ID for this testing process and associated with all process data and judgment results generated during the testing process; After the testing process is completed, the associated complete data package is uploaded and stored in the database, which supports querying and tracing by the product's unique number; Before storing the data packet, verify whether the product ID in the data packet is consistent with the initially obtained product unique number. If they are inconsistent, trigger a binding error alarm.

[0005] The determination condition for reaching the first target detection force or the second target detection force is: the force value fed back by the force sensor is stable within the preset error range of the target value and remains stable for a preset time. When the judgment condition is met, a hardware trigger signal is sent to the displacement detection device through the digital output port of the PLC to synchronously latch and collect the displacement value.

[0006] The process of controlling the lateral loading device to apply the first target detection force or the second target detection force includes an approach phase and a force-controlled contact phase. The approach phase is used to control the servo electric cylinder to move toward the pedal lateral loading point at a first speed; The force-controlled contact stage is used to switch to force closed-loop control when the force sensor detects that the contact force exceeds the contact threshold; when the real-time force value reaches the first target detection force or the first ratio of the second target detection force, predictive deceleration is initiated; when the real-time force value enters the fine-tuning window of the first target detection force or the second target detection force, the servo electric cylinder is controlled to perform creeping fine-tuning at the second speed until the force value stabilizes within the target error band, and the second speed is less than the first speed.

[0007] The fixed pedal assembly includes an adaptive clamping step: Detect the pedal placement signal; The control clamping mechanism drives the clamping head to move towards the pedal surface; After the contact sensor switch is triggered, it switches to the set speed for clamping and reads the value of the clamping force sensor in real time; Closed-loop control is used to stabilize the clamping force within the target clamping force range, while simultaneously verifying whether the displacement of the clamping head is within the permissible window. The clamping is considered successful only when both the clamping force and displacement conditions are met.

[0008] In a second aspect, the present invention provides a brake pedal wobble detection system, applied to a brake pedal wobble detection method as provided in the first aspect, comprising: A positioning and fixing device is used to fix the pedal assembly under test by simulating the vehicle mounting angle; The lateral loading device includes a servo electric cylinder and a force sensor mounted on its force application end, for applying a set first target detection force or a second target detection force to the side of the pedal; A displacement detection device is used to detect the lateral displacement of the test pedal under load in real time. A control and processing device is electrically connected to the lateral loading device and the displacement detection device. The control and processing device includes a PLC and an industrial control computer. The PLC is used to control the movement of the servo electric cylinder, receive signals from the force sensor and the displacement detection device, and calculate the total lateral sway of the pedal. The industrial control computer is used for human-machine interaction, data storage, and traceability.

[0009] The positioning and fixing device includes a clamping mechanism and a pedal positioning photoelectric sensor; The clamping mechanism includes a power unit, a transmission mechanism, a clamping head module, and a clamping force sensor and a displacement detection unit integrated on the clamping head module or the transmission mechanism, which are used to realize automatic clamping of the pedal and dual confirmation of the clamping status. The pedal positioning photoelectric sensor is installed on the side of the product positioning base and is used to detect whether the pedal is in place.

[0010] The PLC is equipped with an adaptive force control algorithm module, which controls the servo electric cylinder to perform a loading process including an approach phase, a force control contact phase, and a stable holding phase. During the force control contact phase, the PLC achieves closed-loop control of the force value and triggering of the position based on the real-time feedback of the force sensor.

[0011] This invention discloses a method and system for detecting brake pedal wobble. After fixing the pedal at a simulated vehicle mounting angle, a servo electric cylinder sequentially applies a force of ±9.8N to its side. Force-controlled contact and displacement synchronous triggering technology are used to accurately collect displacement values ​​from both sides. The total wobble is calculated and compared with a standard value (e.g., ≤4mm) for judgment. The system includes a positioning and fixing device, a lateral loading device, a displacement detection device, and a control and processing device. This invention achieves fully automatic, high-precision detection and real-time judgment of pedal wobble. Furthermore, by automatically identifying and binding product numbers, it ensures accurate traceability of individual test data, effectively improving product quality control and production efficiency. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0013] Figure 1 This is a schematic diagram of the steps of a brake pedal wobble detection method according to the first embodiment of the present invention.

[0014] Figure 2 This is a flowchart illustrating a method for detecting brake pedal wobble provided by the present invention.

[0015] Figure 3This is a schematic diagram of a brake pedal wobbling detection system according to the second embodiment of the present invention.

[0016] Figure 4 This is a schematic diagram of a brake pedal wobbling detection system according to the second embodiment of the present invention.

[0017] Figure 5 This is a schematic diagram of the electronic device of the present invention.

[0018] In the diagram: 101-positioning and fixing device, 102-lateral loading device, 103-displacement detection device, 104-control and processing device, 105-servo electric cylinder, 106-force sensor, 107-industrial control computer, 108-NG box, 109-test pedal. Detailed Implementation

[0019] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0020] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0021] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0022] The first embodiment of this application is as follows: Please see Figures 1-2 This invention provides a method for detecting brake pedal wobble, comprising the following steps: S1. Fix the pedal assembly to be tested at the testing station at a simulated vehicle mounting angle.

[0023] Specifically, the operator places the brake pedal assembly to be tested on the product positioning base of the testing fixture, ensuring the pedal is positioned at the same angle as when it is installed on the vehicle. At this point, the pedal positioning photoelectric sensor mounted on the side of the base is triggered, sending a "pedal placed" signal to the PLC. The system enters a ready state, and the operator then presses the dual start button (pressing both sides simultaneously or sequentially as a safety interlock mechanism). After receiving the start signal, the PLC first confirms the pedal positioning signal is valid again, then initiates the automatic clamping process of the clamping mechanism. Simultaneously, the product ID is scanned and bound.

[0024] The clamping control logic is as follows: The PLC-controlled power unit drives the clamping head module to move rapidly downwards (rapid approach stage). When the contact-sensing microswitch mounted on the clamping head is triggered (indicating contact with the pedal surface), the system immediately switches to the low-speed precision clamping stage. During this stage, the PLC reads the clamping force sensor value in real time and compares it with the preset target clamping force range (e.g., 500N ± 20N). The system employs a closed-loop PID control algorithm to dynamically adjust the power unit output until the measured clamping force stabilizes within the target range and remains there for a predetermined time (e.g., 0.5 seconds) to ensure stable clamping.

[0025] In this embodiment, the closed-loop PID control algorithm is implemented using a standard PID function block integrated within the programmable logic controller (PLC). This function block requires no complex formulas from the user; it can be used simply by configuring parameters. The specific process of dynamically adjusting the power unit output is as follows: First, the PLC reads the electrical signal (e.g., 4-20mA current signal) output by the clamping force sensor installed on the clamping head in real time through the analog input module, and converts it into the current measured clamping force value (unit: Newton).

[0026] Secondly, the PLC sets a target clamping force value (e.g., 500 Newtons) in the program and compares the measured clamping force with the target value to calculate the deviation. If the measured force is less than the target value, it means that the clamping needs to continue; if the measured force is greater than the target value, it means that the clamping has been over-clamped and needs to be slightly reduced.

[0027] Then, the PLC sends the aforementioned deviation value to the PID function block. This function block automatically calculates an output control quantity based on three parameters (proportional gain, integral time, and derivative time) pre-tuned by the user. This control quantity is a value between 0% and 100%, representing the drive intensity that needs to be applied to the power unit.

[0028] Next, the PLC converts the control quantity into a corresponding analog signal (e.g., 0-10V voltage or 4-20mA current) through the analog output module and sends it to the power unit (in this embodiment, the driver of the servo electric cylinder or the proportional pressure valve). The power unit adjusts its output torque or propulsion speed in real time according to the received analog signal: the larger the control quantity, the stronger the power unit output and the faster the pressing head moves; the smaller the control quantity, the weaker the output and the slower the movement; if the control quantity is zero or negative, it stops moving forward or reverses slightly.

[0029] Finally, the above process of "reading force value → calculating deviation → PID calculation → output control → adjustment execution" is repeated at extremely short time intervals (e.g., once every 10 milliseconds), forming a closed-loop control loop. As the clamping head gradually approaches the pedal surface, the measured force value gradually approaches the target value, the deviation becomes smaller and smaller, and the control quantity output by the PID also decreases accordingly, automatically slowing down the movement speed of the clamping head. When the measured force value enters the target allowable error range (e.g., 500 Newtons ± 20 Newtons), the control quantity becomes very small, and the clamping head only performs creeping fine adjustments at an extremely slow speed until the force value is completely stable within the target range. Once the measured force value remains stable within the allowable error range for a preset time (e.g., 0.5 seconds), the PLC determines that the clamping force is stable and ends the PID adjustment process.

[0030] The preset clamping force range is based on a comprehensive consideration of the following three dimensions: Product structural strength analysis: By analyzing the material properties and structural stress of the brake pedal assembly, a maximum safe clamping force is determined that can reliably secure the pedal without causing plastic deformation or damage. This value is usually provided by the product design department and is derived from finite element simulation analysis or destructive testing data of the pedal.

[0031] Stability requirements for the testing benchmark: Insufficient clamping force may cause the pedal to shift or vibrate during lateral loading, interfering with the accuracy of the sway measurement; excessive clamping force may cause pre-deformation of the pedal, also affecting the accuracy of the test. Therefore, the clamping force needs to be set within a range that is "sufficiently stable and does not introduce additional errors." This "sufficiently stable and does not introduce additional errors" clamping force range means that the clamping force value range simultaneously meets two conditions: First, the clamping force is large enough to reliably fix the pedal to be tested on the testing fixture, preventing overall movement, swaying, or elastic jumping during subsequent lateral loading. This ensures that the displacement value collected by the displacement detection device accurately reflects the pedal's own sway, rather than the overall displacement of the fixture or product. Second, the clamping force cannot be too large, as this may cause permanent indentations, elastic pre-deformation, or localized stress in the pedal's plastic or metal structure. Otherwise, it will change the original mechanical properties of the pedal in its free state, leading to an overestimation or underestimation of the sway, introducing testing errors.

[0032] The specific values ​​for this clamping force range can be determined for a specific model of brake pedal through the following three steps: Step 1: Determine the upper limit based on the product's structural strength: The product design department provides the maximum safe clamping force that the pedal can withstand in the clamping direction. This data is usually obtained from three-dimensional finite element simulation analysis of the pedal or through destructive clamping tests on actual samples. The test method is as follows: Take an intact pedal sample, gradually increase the clamping force at the clamping position, and observe whether the pedal surface shows signs of damage such as white marks, cracks, or permanent dents. The clamping force value at which the above damage first appears is multiplied by a safety factor (e.g., 0.7 to 0.8), which is taken as the upper limit of the clamping force range. For example, if the pedal begins to show surface indentations at 600 Newtons, then the safe upper limit is taken as 480 Newtons.

[0033] Step 2: Determine the lower limit value based on detection stability: Take multiple pedal samples (e.g., 10) from the same batch and model, and test the wobble using varying clamping forces, from low to high. Start with a low clamping force, such as 100 Newtons, increasing by 50 Newtons each time until approaching the upper limit obtained in the first step. For each clamping force level, repeat the test multiple times for the same pedal (e.g., 5 times), calculating the repeatability of the wobble test results (i.e., the difference between the maximum and minimum values) and the dispersion between different pedals from the same batch. Select the clamping force value that provides the best repeatability and the smallest dispersion as a reference for the lower limit. Generally, test results fluctuate greatly when the clamping force is too low; as the clamping force increases, the fluctuation gradually decreases and tends to stabilize. The starting point of this stable interval is taken as the lower limit of the clamping force. For example, if the experiment shows that the test results become stable and repeatable when the clamping force starts at 250 Newtons, then the lower limit can be taken as 250 Newtons.

[0034] Step 3: Verify and fine-tune based on engineering experience: The upper limit obtained in the first step and the lower limit obtained in the second step are combined to form an initial range (e.g., 250 Newtons to 480 Newtons). An intermediate value (e.g., 365 Newtons) is selected for small-batch trial production (e.g., 50 to 100 pedals), and the normal distribution and pass rate of the test data are statistically analyzed. If it is found that excessive clamping force causes slight deformation of some pedals or an abnormal drop in the pass rate, the upper limit is appropriately lowered; if it is found that insufficient clamping force causes occasional data fluctuations, the lower limit is appropriately raised. After 2 to 3 rounds of fine-tuning, the finally determined range can be used as the target range of clamping force for mass production of this model of pedal. In this embodiment, the exemplary target clamping force range is 500 Newtons ± 20 Newtons, i.e., 480 Newtons to 520 Newtons.

[0035] Historical data and process experience: For mass-produced products, the optimal clamping force range can be deduced by statistical analysis of the test data during the early small-batch trial production, so as to achieve the best repeatability and the smallest dispersion of the test results.

[0036] Different brake pedal models have different clamping force requirements due to differences in their structure, materials, and dimensions. The system uses a model-parameterized configuration method to achieve dynamic adjustment. Product Model Identification: Before the inspection process begins, the operator scans the product barcode using a barcode scanner. This barcode contains not only the product's unique serial number but also an embedded product model code. The industrial control computer automatically extracts this model code when parsing the barcode.

[0037] Parameter table retrieval: The industrial control computer has a built-in model parameter configuration table, which pre-stores key parameters such as the target clamping force, allowable error range, target loading force, and sway judgment threshold for all in-production pedal models. When a specific model is identified, the system automatically retrieves the corresponding clamping force parameters from the configuration table and sends them to the PLC via the industrial Ethernet.

[0038] Dynamic parameter updates: When a new product model is imported, simply add a new record in the parameter configuration interface of the industrial control computer, input the corresponding clamping force and other parameters for that model, and the system can support the detection of the new product without modifying the PLC program or hardware structure.

[0039] Error prevention check: If the scanned product model does not exist in the configuration table, the system will immediately pop up a prompt "Unknown product model, please configure parameters first" and prevent the detection process from starting, to prevent detection failure or product damage caused by using incorrect parameters.

[0040] To ensure reliable clamping, the system employs a dual confirmation mechanism: Force confirmation: As mentioned above, the measured value of the clamping force sensor must be within the preset range.

[0041] Displacement Confirmation: During the clamping process, the displacement sensor records the final stroke position of the clamping head. This position must fall within the permissible displacement window preset according to the product model. If the displacement is too small, it may indicate that the pedal is not placed in place or that there is a foreign object; if the displacement is too large, it may indicate that the product model is incorrect or that there is a structural abnormality.

[0042] The PLC will only determine "successful clamping" and illuminate the status indicator light when both "clamping force confirmation" and "displacement confirmation" conditions are met simultaneously. If either condition is not met, the system will immediately stop the loading process, control the clamping mechanism to automatically release and reset, and simultaneously display a clear alarm message (such as "abnormal clamping force" or "product positioning error") on the industrial control computer 107 screen to guide the operator to check the product and tooling.

[0043] S2. Control the lateral loading device 102 to apply a first target detection force in a first direction to the first side of the test pedal 109, and trigger the displacement detection device 103 to record the first displacement value when the first target detection force is reached.

[0044] S3. Control the lateral loading device 102 to apply a second target detection force opposite to the first direction on the second side of the test pedal 109, and trigger the displacement detection device 103 to record the second displacement value when the second target detection force is reached.

[0045] S4. Based on the first displacement value and the second displacement value, calculate the total lateral sway of the test pedal 109.

[0046] S5. Compare the total lateral sway with the preset tolerance upper limit to determine whether the pedal is qualified.

[0047] Specifically, since steps S2 and S3 differ only in direction but share the same control principle, they are described together to avoid redundancy. Similarly, due to the close connection between steps S4 and S5 and steps S2 and S3, the entire solution is described together to ensure clarity and completeness.

[0048] The lateral loading process is achieved by a precision servo force control system, which consists of the following core components forming a closed-loop control circuit: Actuation unit: High-precision servo electric cylinder 105 with built-in high-resolution encoder for precise control of displacement and speed.

[0049] Force detection unit: A high dynamic response force sensor 106 installed at the front end of the servo electric cylinder 105 monitors the actual applied load in real time.

[0050] Control unit: A coordinated control system consisting of a programmable logic controller (PLC) and a servo driver.

[0051] Data processing unit: Industrial control computer 107, which runs host computer monitoring software and is responsible for data recording and analysis.

[0052] The entire lateral loading process is carefully designed into three coherent and intelligent phases: rapid approach phase, force-controlled contact phase, and stable holding phase.

[0053] Phase 1: Rapid Approach Phase.

[0054] After receiving the "compression successful" signal, the PLC sends a command to the servo driver according to the preset program, driving the servo cylinder 105 to move towards the target side (e.g., the left side) at a relatively high initial speed (e.g., 100 mm / s). The goal of this stage is to quickly shorten the idle stroke between the cylinder loading head and the lateral loading point of the brake pedal, thereby increasing the detection cycle time. To ensure safety, the system is equipped with dual protection of software and hardware limits to prevent cylinder overshoot.

[0055] Phase Two: Force-Controlled Contact Phase (Achieving "Fast Contact - Slow Fine-Tuning") When the high dynamic response force sensor 106 detects that the force value exceeds a low threshold (e.g., 0.5N, indicating that the pedal has been contacted), the system immediately triggers a state switch.

[0056] At this point, the adaptive force control algorithm in the PLC takes over. This algorithm receives feedback signals from the force sensor 106 in real time and compares them with the target force value (+9.8N or -9.8N). Its control logic is as follows: Rapid contact: After the initial contact, the servo electric cylinder 105 continues to advance at a relatively high speed, and the force value rises rapidly.

[0057] Predictive deceleration: When the real-time force reaches a first proportion of the target force (e.g., 80%, approximately 7.8N), the adaptive force control algorithm calculates the deceleration curve in advance based on the current force increase rate and instructs the servo drive to begin reducing the electric cylinder's propulsion speed. This predictive deceleration avoids force overshoot caused by system inertia. Predictive deceleration is not a simple proportional control, but rather a feedforward predictive control based on the force change rate, specifically implemented as follows: Force change rate calculation: In each control cycle, the system not only reads the current force value, but also calculates the rate of change of the force value relative to time (i.e., the amount by which the force value increases or decreases per unit time). This rate of change reflects the "contact stiffness" characteristic after the electric cylinder and pedal come into contact—the tighter the contact, the greater the rate of force change.

[0058] Deceleration Timing Prediction: When the real-time force value reaches a preset percentage (e.g., 80%) of the target force value, the system calculates backward based on the current rate of force change: if the current speed is maintained, how long will it take for the force value to reach the target value? If the calculated time is too short (e.g., less than the system response time), it determines that "overshoot is imminent" and immediately initiates a deceleration command in advance.

[0059] Deceleration curve planning: The system dynamically calculates a smooth deceleration curve based on the current force change rate, and instructs the servo drive to reduce the speed according to the curve, so that the electric cylinder reaches the target force value at the same time as the speed is reduced to the minimum, thereby achieving the ideal effect of "stopping as soon as it reaches the target position" and avoiding inertial overshoot.

[0060] Slow fine-tuning: When the force value approaches the target value (e.g., entering the fine-tuning window of 9.8N ± 0.5N), the electric cylinder enters a creeping fine-tuning mode, continuing or reversing the fine-tuning at an extremely low second speed (e.g., 1 mm / s). The algorithm uses incremental PID control to dynamically adjust the position of the electric cylinder, making the feedback value of the force sensor 106 infinitely approach and stabilize at the target force value of 9.8N. Its adjustment method is as follows: Proportional adjustment: The adjustment range is determined based on the current force error. The larger the force error, the larger the single position adjustment, in order to quickly reduce the error.

[0061] Integral adjustment: The system accumulates the total force error over a period of time. If the force error persists for a long time but cannot be eliminated (e.g., static error caused by friction), the integral term will gradually increase, continuously applying adjustment commands until the error is completely eliminated.

[0062] Differential adjustment: The system observes the changing trend of force error. If the force error is decreasing rapidly, the differential term will appropriately reduce the adjustment amount to prevent over-adjustment; if the force error is increasing rapidly, the differential term will increase the reverse adjustment amount in advance, acting as a "brake".

[0063] Output as position increment: Unlike traditional PID controllers that directly output speed or force commands, incremental PID controllers calculate a position increment relative to the current position each time. The PLC adds this increment to the current target position to form a new position command, which is then sent to the servo drive. This method avoids sudden changes in commands caused by integral saturation, resulting in smoother motion.

[0064] Stability is achieved when the force value remains stable at the target value (9.8N ± 0.2N) for a predetermined time (e.g., 100 milliseconds). Stability is determined using a continuous sliding window method. Decision window: The system maintains a force value record queue with a length of 100 milliseconds in memory. Every control cycle (e.g., 1 millisecond), the current force value is stored in the queue and the oldest force value is removed.

[0065] Within-window determination: In each control cycle, the system checks whether all force values ​​within the window fall within the target error band (9.8N ± 0.2N). Only when every force value within the window meets the condition is the system determined to be "stable".

[0066] Continuous compliance requirement: This "full-window compliance" judgment method means that the system requires the force value to not exceed the error band even once within a continuous 100 milliseconds. This is more stringent than the lenient judgment of "average value within range" or "occasional exceedance is acceptable", ensuring that the force value is indeed in a truly stable state at the moment the displacement is collected.

[0067] If, during the stable holding period, the force value of a certain control cycle briefly exceeds the error band: The system immediately resets the stabilization timer, clears the accumulated stabilization time, and starts counting again.

[0068] At the same time, the system automatically invokes the fine-tuning mechanism, instructing the electric cylinder to make minor position corrections based on the current force error, and pull the force value back into the target range.

[0069] Only after the condition of "all values ​​meeting the standard for 100 consecutive milliseconds" is met again will the system determine that the force value is stable and trigger displacement acquisition.

[0070] This rigorous stability determination mechanism, while potentially slightly increasing the detection time for individual products, significantly improves the repeatability and reliability of displacement acquisition, and is key to ensuring the accuracy of the final sway measurement results.

[0071] The core of the adaptive force control algorithm lies in converting the real-time feedback value from the force sensor into motion commands for the servo electric cylinder. Its basic logic is as follows: Error calculation: In each control cycle (e.g., 1 millisecond), the PLC program reads the real-time force value from the force sensor and subtracts it from the target force value to obtain the current force error. A positive force error indicates that the current force value is less than the target value, and the process needs to continue; a negative force error indicates that the current force value has exceeded the target value, and the process needs to reverse.

[0072] Control mode switching: Based on the magnitude of the force error, the algorithm automatically determines whether the current stage is "rapid approach", "deceleration approach" or "fine-tuning and holding", and decides the movement speed and direction of the servo electric cylinder.

[0073] Speed ​​command generation: During the rapid approach phase, the force error is relatively large, and the system drives the electric cylinder at a preset constant high speed. Once the force error enters the preset deceleration threshold range, the speed command becomes positively correlated with the magnitude of the force error—the larger the force error, the faster the speed; the smaller the force error, the slower the speed. This proportional relationship of "the larger the error, the faster the speed" ensures a smooth transition from high speed to low speed.

[0074] Position command generation: During the fine-tuning stage, the system no longer directly controls the speed, but converts the force error into a tiny position increment command. Each time, the electric cylinder is only commanded to move a very small distance (e.g., 0.01 mm), and then the force value is read again, forming an iterative cycle of "position fine-tuning - force value reading - fine-tuning again" until the force value stabilizes within the target range.

[0075] Phase 3: Stability Maintenance and Data Acquisition Phase.

[0076] Once the force is applied, the servo cylinder 105 immediately enters the position lock mode, and the servo driver maintains the current position to maintain a constant force output (within the elastic deformation range). Simultaneously, the PLC issues a command to trigger the displacement sensor to acquire the absolute displacement value of the brake pedal loading point at that moment. This displacement value is read in real-time by the PLC as a digital signal via an analog input module or a dedicated high-speed counting module.

[0077] When the servo electric cylinder 105 adjusts through the adaptive force control algorithm during the force control contact phase, so that the feedback value of the high dynamic response force sensor 106 is stabilized within the allowable error range (e.g., ±0.2N) of the target force value (±9.8N) and continues to be stable for more than the preset stabilization time (e.g., 100 milliseconds), the force value stabilization judgment logic in the PLC will immediately set a hardware-triggerable "force value reached" flag signal.

[0078] This flag signal is directly output as a pulse signal to the external trigger sampling port of the displacement sensor via the PLC's high-speed digital output channel. Compared to software polling, this hardware triggering method offers extremely high real-time performance and determinism, ensuring that displacement acquisition and force stability are synchronized within microseconds.

[0079] Upon receiving a trigger pulse, the displacement sensor immediately latches its currently measured analog displacement signal and converts it into a digital value via its built-in analog-to-digital converter. This digital displacement value, representing the current position of the pedal, is read in real time by the PLC's dedicated position acquisition module through the displacement sensor's digital interface (such as SSI or a high-speed parallel interface).

[0080] After reading the displacement value, the PLC's dedicated position acquisition module first performs data verification (such as parity check or CRC check) to ensure that the data is error-free during transmission. Once the verification is successful, the displacement value is stored in the PLC's safety data register area. The PLC program then binds and packages the acquired displacement value with the current loading direction (left / right), the corresponding stabilizing force value, and a precise timestamp, forming a raw data packet, which is temporarily stored in the PLC's non-volatile memory.

[0081] Once loading is complete on both the left and right sides, and the displacement data packets in both directions are ready, the PLC invokes the sway calculation engine. This engine performs the following calculations: a. Take the absolute values ​​of the two displacement values ​​respectively.

[0082] b. Add the two absolute values ​​to obtain the measured total sway.

[0083] c. Compare the measured total wobble with the preset upper limit of tolerance (4mm).

[0084] The comparison result immediately generates a product status code: "0" represents OK, and "1" represents NG. This status code, together with the measured total shaking value, constitutes the core judgment result.

[0085] Once the result is NG, the system immediately initiates a multi-level collaborative early warning process: Level 1: Real-time alerts on the human-computer interface A high-priority NG (Not Acceptable) pop-up immediately appears in the center of the industrial control computer's monitoring screen. The pop-up clearly displays: product number, measured total shaking amount, exceeding value, judgment criteria, and details of the non-conforming side (left / right).

[0086] A specific area of ​​the screen or the entire screen border flashes red, accompanied by an audible warning (a continuous beeping sound or voice prompt "product defective").

[0087] Level 2: Hardware Instructions and Process Locking The three-color alarm light installed on the machine illuminates red and flashes.

[0088] The PLC automatically locks all start and run buttons except the release button for the clamping mechanism to prevent accidental operation. The system will only proceed to the next step (releasing the clamp) after the operator presses the dedicated NG confirmation / reset button.

[0089] Level 3: Physical sorting guidance and data tagging Following the instructions, operators must manually remove NG products and place them in a dedicated NG storage box with a prominent "Non-conforming Product" label.

[0090] When a product is placed in the NG box 108, a simple photoelectric sensor or weight sensor can be set up to send a "NG product disposed of" signal to the system. This signal is recorded and associated with the product's detection data package, forming a closed-loop disposal process.

[0091] In the database and industrial control computer's inspection history query system, this record is permanently marked as "NG" and highlighted for easy subsequent quality traceability and analysis.

[0092] Meanwhile, to facilitate quality traceability and analysis, a fixed industrial barcode scanner or RFID reader is installed at the beginning of the inspection station. Before placing the brake pedal onto the positioning base, the operator first uses the scanner to scan the unique identification mark (1D barcode, 2D barcode, or RFID tag) affixed to the pedal bracket. The scan signal is directly transmitted to the industrial control computer's data management software via serial port or Ethernet.

[0093] The software performs format verification on the scanned serial numbers. After successful verification, the unique serial number of the product is temporarily stored in the memory of the industrial control computer and simultaneously sent to the PLC via Ethernet. It is then stored in a designated register of the PLC as the "current product ID" for this inspection cycle.

[0094] Throughout the entire testing process (compression, left loading, right loading, and judgment), all raw data packets and core judgment results generated by the PLC are automatically associated with the "current product ID" stored internally by the PLC.

[0095] When the testing process is completely finished (regardless of whether it is OK or NG), the PLC will package and upload all process data and result data associated with the product ID to the industrial control computer in one go via industrial Ethernet.

[0096] After receiving data packets, the industrial control computer's data management software writes them to the local SQL database while simultaneously synchronizing them to the central server database via the workshop network. During the write process, a composite primary key is used, consisting of the "product unique number" and the "inspection timestamp," to ensure the uniqueness and traceability of each record.

[0097] After receiving the complete data packet from the PLC, the industrial control computer compares the product ID with the previously scanned and temporarily stored ID. If they do not match, a serious alarm is triggered, indicating a "data binding error," to prevent data corruption caused by signal interference or program malfunctions. Each qualified product, upon leaving the workstation, can have a miniature traceability label printed, containing the product number, key inspection data, inspection date, and an OK mark, which is then affixed to the product packaging, achieving both physical and digital traceability. The system is designed for "one item, one inspection, one binding." Scanning of a new product is only effective after the inspection process of the previous product is completely completed and the data binding is successfully stored, thus preventing missed inspections or data overlap.

[0098] Data binding verification occurs at the end of the detection process and when the data is ready for storage. The specific verification logic is as follows: Dual-end data consistency verification: After receiving the complete data packet uploaded by the PLC, the industrial control computer extracts the "Product ID" field and compares it character by character with the "Currently Scanned Product ID" temporarily stored in the local memory of the industrial control computer.

[0099] Verification Algorithm: The comparison not only requires the strings to be completely identical, but also performs an additional checksum verification. That is, when the data packet is generated, the PLC calculates the checksum of the product ID string and appends this checksum to the data packet; after receiving it, the industrial control computer recalculates the checksum of the product ID and compares it with the checksum in the data packet. This double verification ensures that no bit errors or garbled characters occur during data transmission.

[0100] Timing integrity verification: The system also checks whether the timestamp in the data packet matches the time window of the current detection process to prevent data misalignment caused by communication delays.

[0101] When the verification fails (i.e., the product IDs on both ends are inconsistent or the checksums do not match), the system enters the exception handling branch: Level 1: Immediate Alarm: A prominent red alarm window pops up on the industrial control computer screen, displaying the message "Data binding error: Product ID does not match, please check the scanning and testing process," accompanied by a continuous beeping sound. The on-site three-color alarm lights illuminate red and flash continuously.

[0102] Level 2: Process Lockout: The PLC automatically locks all detection start buttons, preventing the detection of the next product until the anomaly is manually confirmed and handled. This prevents the risk of erroneous data being overwritten or confused.

[0103] Level 3: Anomaly Data Marking and Storage: The system binds all raw data generated during this inspection (including force curves, displacement data, etc.) to a temporarily generated anomaly ID and stores it in the "Anomaly Data Table" of the database. This anomaly ID is associated with the product ID temporarily stored in the industrial control computer and the product ID uploaded by the PLC for easy manual verification later. This step ensures that even if a binding error occurs, the inspection data itself will not be lost and can be used for post-inspection analysis by quality engineers.

[0104] Level 4: Manual intervention and retry mechanism: Based on the alarm prompts, operators check whether the physical barcode on the product is clear and readable, and confirm whether the barcode scanner is working properly.

[0105] Operators can choose between "re-scanning and binding" or "manually entering the product ID" through the "anomaly handling interface" of the industrial control computer.

[0106] If you choose to rescan the barcode, the system will clear the currently stored product ID, requiring the operator to rescan the product barcode and rebind the product ID to the current test data.

[0107] If manual input is selected, authorized personnel must enter the correct product ID. The system will then record the operation log and complete the data binding.

[0108] After a successful retry, the system moves the data previously stored in the "Abnormal Data Table" to the formal test record table and binds it to the correct product ID.

[0109] Level 5: Record Keeping: All verification failure events, alarm records, manual intervention operations, retry results, etc., are stored in the database as system logs, forming a complete operation traceability chain, which facilitates subsequent quality audits and system optimization.

[0110] To prevent frequent verification failures, the system also incorporates the following error prevention designs: Process interlocking: The scanner is only allowed to read the barcode of the next product after the data of the current product has been successfully stored, thus preventing data misalignment caused by "the previous product not being completed before the next product has been scanned".

[0111] Real-time status prompts: The status bar at the top of the industrial control computer screen always displays the "Currently Detected Product ID," allowing operators to check at any time whether the product being detected matches the one displayed on the screen.

[0112] Periodic self-test: When the system is started for the first time each day, it will automatically perform a communication loop test, send test data to the PLC and receive the feedback, verifying the integrity of the industrial Ethernet communication link and data verification function.

[0113] Integrate the above processes, as shown in the appendix. Figure 2 As shown, the summary is as follows: Start: System power-on initialization.

[0114] Product ID binding via barcode scanning: The operator places the pedal to be tested on the positioning base, obtains the unique product number through a barcode scanner or RFID reader, and transmits it to the industrial control computer and PLC as the current product ID.

[0115] Fixed pedal: After the system detects the pedal position signal, it controls the clamping mechanism to automatically press the pedal. Closed-loop PID control is used to stabilize the clamping force within the target range and confirm that the displacement of the clamping head is within the permissible window.

[0116] Force is applied from both sides of the servo motor: including left-side loading and right-side loading; Leftward loading: The servo electric cylinder is controlled to apply a target detection force of +9.8N to the first side of the pedal (such as the left side). Force-controlled contact and predictive deceleration algorithm are used. After the force value stabilizes, the displacement detection device is triggered by hardware to record the first displacement value.

[0117] Rightward loading: Similarly, apply a target detection force of -9.8N to the second side, and record the second displacement value after stabilization.

[0118] Calculate the sway: Add the absolute value of the first displacement to the absolute value of the second displacement to obtain the total lateral sway.

[0119] Judgment: Compare the total wobble with the preset upper tolerance limit (e.g., ≤4mm): If ≤4mm, it is considered qualified (OK); If the diameter is greater than 4mm, it is judged as unqualified (NG) and triggers an audible and visual alarm, interface prompts, locks the start button, and requires manual recording and handling of the signal.

[0120] Data is bound to product IDs for storage: Product IDs are bound to testing process data and judgment results to form a complete data package, which is then uploaded to the database.

[0121] End: Release the clamps, remove the product, and wait for the next test.

[0122] The second embodiment of this application is as follows: Please see Figures 3-4 This invention provides a brake pedal wobble detection system, applied to a brake pedal wobble detection method as provided in the first embodiment, comprising: Positioning and fixing device 101 is used to fix the pedal 109 assembly under test by simulating the vehicle mounting angle; The lateral loading device 102 includes a servo electric cylinder 105 and a force sensor 106 installed at its force application end, for applying a set first target detection force or a second target detection force to the side of the pedal. The displacement detection device 103 is used to detect the lateral displacement of the test pedal 109 under the action of the loading force in real time. The control and processing device 104 is electrically connected to the lateral loading device 102 and the displacement detection device 103. The control and processing device 104 includes a PLC and an industrial control computer 107. The PLC is used to control the movement of the servo electric cylinder 105, receive signals from the force sensor 106 and the displacement detection device 103, and calculate the total lateral sway of the pedal. The industrial control computer 107 is used for human-machine interaction, data storage and traceability.

[0123] The clamping mechanism includes a power unit, a transmission mechanism, a clamping head module, and a clamping force sensor and a displacement detection unit integrated on the clamping head module or the transmission mechanism, which are used to realize automatic clamping of the pedal and dual confirmation of the clamping status. The pedal positioning photoelectric sensor is installed on the side of the product positioning base and is used to detect whether the pedal is in place.

[0124] The PLC is equipped with an adaptive force control algorithm module, which controls the servo electric cylinder 105 to perform a loading process including an approach phase, a force control contact phase, and a stable holding phase. In the force control contact phase, the PLC realizes closed-loop control of the force value and triggering of the position based on the real-time feedback of the force sensor 106.

[0125] In this embodiment, the mechanism of the brake pedal wobble detection system is as follows: Figure 4As shown, the installation steps are as follows: 1. Rack assembly → 2. Machine installation → 3. PLC electrical control cabinet and NG parts storage box installation → 4. Detection device mounting base installation → 5. Product fixing clamp component installation → 6. Shaking detection component installation → 7. Industrial control computer 107 installation → 8. Electrical circuit installation of the two main modules: PLC control and industrial computer display and storage → 9. Upper computer and lower computer program writing and debugging → 10. Verification, acceptance and delivery for use.

[0126] Operating procedures during operation: Normal operation: 1. Manually place the product to be tested in the product clamp → 2. Hold the product with your left hand and press the start button on the right side with your right hand → 3. Fix the clamp to press the product tightly → 4. Press the start button on the left and right sides simultaneously (maintain for about 0.3 seconds) → 5. The sway detection device automatically and intelligently detects and records the lateral sway of the brake pedal (detection time is about 9 seconds) → 6. After the product test is completed, manually remove the product.

[0127] The loading logic for the left side of the servo electric cylinder 105 is as follows: the electric cylinder moves quickly to the left → when it contacts the loading point on the right side and reaches the set force value of 9.8N → the electric cylinder stops → if the force sensor 106 detects a value > 9.8N (considering the inertia of the electric cylinder and the response time of the acquisition card, etc.) → the electric cylinder moves slowly to the right → when 9.8N is detected again → the electric cylinder stops → the displacement sensor acquires the current displacement value.

[0128] PLC Algorithm: Continuing the analysis of the electric cylinder loading logic above; after the left side of the electric cylinder is loaded, the current displacement value collected by the displacement sensor is stored in the PLC's data storage area (such as the data register starting with D100; note: floating-point numbers occupy two data register addresses). The displacement value loaded on the right side follows the same algorithm as the left side. The absolute value of the left displacement + the absolute value of the right displacement = the total pedal wobble. The total wobble ≤ 4mm (OK), the total wobble > 4mm (NG). Regarding the system in the above embodiments, the specific ways in which each module performs operations have been described in detail in the embodiments related to the method, and will not be elaborated here.

[0129] For the system embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0130] Accordingly, this application also provides an electronic device, including: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the brake pedal wobble detection method as described above. Figure 5 The diagram shown is a hardware structure diagram of any device with data processing capabilities, including a brake pedal sway detection system provided in an embodiment of the present invention. (Except for...) Figure 5 In addition to the processor, memory, and network interface shown, any data processing device in the embodiment may also include other hardware depending on the actual function of the data processing device, which will not be described in detail here.

[0131] Accordingly, this application also provides a computer-readable storage medium storing computer instructions thereon, which, when executed by a processor, implement the brake pedal wobbling detection method described above. The computer-readable storage medium can be an internal storage unit of any data-processing device as described in any of the foregoing embodiments, such as a hard disk or memory. The computer-readable storage medium can also be an external storage device, such as a plug-in hard disk, smart media card (SMC), SD card, flash card, etc., equipped on the device. Furthermore, the computer-readable storage medium can include both internal storage units of any data-processing device and external storage devices. The computer-readable storage medium is used to store the computer program and other programs and data required by the data-processing device, and can also be used to temporarily store data that has been output or will be output.

[0132] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0133] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for detecting brake pedal wobble, characterized in that, Includes the following steps: The pedal assembly to be tested is fixed at the testing station at a simulated vehicle mounting angle. The lateral loading device is controlled to apply a first target detection force in a first direction to the first side of the test pedal, and when the first target detection force is reached, the displacement detection device is triggered to record the first displacement value. The lateral loading device is controlled to apply a second target detection force opposite to the first direction on the second side of the test pedal, and when the second target detection force is reached, the displacement detection device is triggered to record the second displacement value; Based on the first displacement value and the second displacement value, calculate the total lateral sway of the test pedal; The total lateral sway is compared with the preset tolerance upper limit to determine whether the pedal is qualified; After being determined to be unqualified, the method further includes: An NG warning pop-up window appears on the human-machine interface of the industrial control computer, containing the product number, the measured shaking amount, and information on exceeding the standard, and an audible and visual alert is issued. The control panel activates the three-color alarm light at the site, which illuminates red and flashes, and locks the start button except for the release button of the depressurization clamp. Acquire the processing completion signal and associate it with the detection data record of the corresponding test pedal; The method further includes: Before the pedal to be tested is placed, a unique number is obtained by scanning a barcode or using an RFID reader and then transmitted to the industrial control computer and PLC. The unique number will be used as the current product ID for this testing process and associated with all process data and judgment results generated during the testing process; After the testing process is completed, the associated complete data package is uploaded and stored in the database, which supports querying and tracing by the product's unique number; Before storing the data packet, verify whether the product ID in the data packet is consistent with the initially obtained product unique number. If they are inconsistent, trigger a binding error alarm.

2. The brake pedal wobble detection method as described in claim 1, characterized in that, The determination condition for achieving the first target detection force or the second target detection force is: the force value fed back by the force sensor is stable within the preset error range of the target value and remains stable for a preset time. When the judgment condition is met, a hardware trigger signal is sent to the displacement detection device through the digital output port of the PLC to synchronously latch and collect the displacement value.

3. The brake pedal wobble detection method as described in claim 1, characterized in that, The process of controlling the lateral loading device to apply the first target detection force or the second target detection force includes an approach phase and a force-controlled contact phase; The approach phase is used to control the servo electric cylinder to move toward the pedal lateral loading point at a first speed; The force-controlled contact phase is used to switch to force closed-loop control when the force sensor detects that the contact force exceeds the contact threshold; and to initiate predictive deceleration when the real-time force value reaches a first proportion of the first target detection force or the second target detection force. When the real-time force value enters the fine-tuning window of the first target detection force or the second target detection force, the servo electric cylinder is controlled to perform creeping fine-tuning at the second speed until the force value stabilizes within the target error band. The second speed is less than the first speed.

4. The brake pedal wobble detection method as described in claim 1, characterized in that, The fixed pedal assembly includes an adaptive clamping step: Detect the pedal placement signal; The control clamping mechanism drives the clamping head to move towards the pedal surface; After the contact sensor switch is triggered, it switches to the set speed for clamping and reads the value of the clamping force sensor in real time; Closed-loop control is used to stabilize the clamping force within the target clamping force range, while simultaneously verifying whether the displacement of the clamping head is within the permissible window. The clamping is considered successful only when both the clamping force and displacement conditions are met.

5. A brake pedal wobble detection system, applied to the brake pedal wobble detection method as described in any one of claims 1 to 4, characterized in that, include: A positioning and fixing device is used to fix the pedal assembly under test by simulating the vehicle mounting angle; The lateral loading device includes a servo electric cylinder and a force sensor mounted on its force application end, for applying a set first target detection force or a second target detection force to the side of the pedal; A displacement detection device is used to detect the lateral displacement of the test pedal under load in real time. A control and processing device is electrically connected to the lateral loading device and the displacement detection device. The control and processing device includes a PLC and an industrial control computer. The PLC is used to control the movement of the servo electric cylinder, receive signals from the force sensor and the displacement detection device, and calculate the total lateral sway of the pedal. The industrial control computer is used for human-machine interaction, data storage, and traceability.

6. The brake pedal wobble detection system as described in claim 5, characterized in that, The positioning and fixing device includes a clamping mechanism and a pedal positioning photoelectric sensor; The clamping mechanism includes a power unit, a transmission mechanism, a clamping head module, and a clamping force sensor and a displacement detection unit integrated on the clamping head module or the transmission mechanism, which are used to realize automatic clamping of the pedal and dual confirmation of the clamping status. The pedal positioning photoelectric sensor is installed on the side of the product positioning base and is used to detect whether the pedal is in place.

7. The brake pedal wobble detection system as described in claim 6, characterized in that, The PLC is equipped with an adaptive force control algorithm module, which is used to control the servo electric cylinder to perform a loading process including an approach phase, a force control contact phase, and a stable holding phase. In the force control contact phase, the PLC realizes closed-loop control of the force value and triggering of the position based on the real-time feedback of the force sensor.

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