Height sensor failure detection and processing method

Abstract

The invention relates to the technical field of sensor detection, in particular to a height sensor failure detection and processing method, which comprises the following steps of: controlling a vehicle to execute standard ascending and descending actions at a plurality of predefined speed sections, and dynamically calculating a reasonable range of a height change rate; in the vehicle driving process, the current operation speed and the corresponding height change rate are monitored in real time, the height change rate is compared with the reasonable range, and when the height change rate exceeds the reasonable range, it is judged that the height sensor fails; when it is judged that the height sensor fails, the operation height is determined based on height data in a preset time window before failure; dynamically calculating safety control parameters according to the operation height; and controlling the vehicle according to the safety control parameters. By dynamically calibrating the change rate threshold value of the height sensor and implementing closed-loop safety control based on the height before failure, the running safety of the vehicle when the sensor fails can be improved.

Description

Technical Field

[0001] This application relates to the technical field of sensor detection, and in particular to a method for detecting and handling the failure of a height sensor. Background Technology

[0002] In industrial vehicles such as high-reach picking trucks, height sensors are core components ensuring operational safety. They monitor the real-time height of the forks or work platform, providing crucial parameter inputs to the vehicle control system and directly impacting the automatic adjustment of travel speed and the precise execution of braking strategies. For example, when the vehicle is performing picking operations at a high position, the system must dynamically limit the vehicle speed and adjust braking intensity based on the real-time height to prevent vehicle instability or even cargo tipping accidents caused by excessive speed or sudden braking. Therefore, the reliability of height sensors is directly related to the safety of people, vehicles, and goods.

[0003] To address potential sensor malfunctions, existing technologies have proposed a series of detection and fault-tolerance schemes. For example, patent document CN115657668B discloses a control method for the working components of a self-moving device. When an abnormality is detected in the height sensor, this method selects different initial height references (such as the previous shutdown height or the last valid height) based on the type of abnormality, and maintains coarse adjustment of the working components in an open-loop control manner through a preset pulse-height mapping relationship. Another patent document, CN116106661A, provides a method for judging the validity of a vehicle height sensor signal. It utilizes the vehicle's body vibration characteristics during high-speed driving to determine whether the sensor is abnormal by detecting whether reasonable fluctuations occur in the height signal.

[0004] However, existing technologies exhibit a fundamental technical flaw when dealing with the complex and varied actual operating conditions of high-bay order pickers: their fault detection logic relies on static or pre-calibrated threshold parameters, failing to adapt to the dynamic changes in vehicle characteristics caused by load variations, mechanical wear, and hydraulic characteristic drift during actual operation. This leads to misjudgments or missed detections under critical conditions. Specifically, in high-bay order picker applications, the empty and fully loaded states of the vehicle result in significant differences in the height change rate of its lifting / lowering mechanism. If a fixed threshold is used for fault judgment, the lower height change rate when the vehicle is empty may be misjudged as sensor failure, causing the system to erroneously trigger the safety mode and affecting operational efficiency. Conversely, during heavy-load rapid descents, an excessively high change rate may be missed because it does not exceed the fixed threshold, preventing the system from timely identifying genuine sensor faults. More seriously, as the vehicle's usage time increases, factors such as internal leakage in the hydraulic system and wear of the transmission mechanism will cause its mechanical characteristics to drift slowly, gradually causing the static threshold calibrated at the factory to become mismatched with the actual dynamic characteristics. This mismatch is particularly prominent when the vehicle is performing low-speed precision work or is in a specific height range. At this time, the sensor may have already experienced a soft failure, but because its output change rate has not yet exceeded the fixed failure threshold, the system will not be able to detect it in time. This will cause the vehicle to make speed and braking control based on incorrect height information, creating serious safety hazards when working at high positions. Summary of the Invention

[0005] In order to improve the operational safety of a vehicle when the height sensor fails by dynamically calibrating the height sensor change rate threshold and implementing closed-loop safety control based on the height before failure, this application provides a height sensor failure detection and processing method.

[0006] This application provides a method for detecting and handling the failure of a height sensor, which adopts the following technical solution: A method for detecting and handling the failure of a height sensor includes the following steps:

[0007] The vehicle is controlled to perform standard lifting and lowering maneuvers at multiple predefined speed ranges, and the reasonable range of the height change rate is dynamically calculated.

[0008] During vehicle operation, the current operating speed and the corresponding height change rate are monitored in real time. The height change rate is compared with the reasonable range. When the height change rate exceeds the reasonable range, the height sensor is determined to be faulty.

[0009] When a height sensor is determined to be faulty, the working height is determined based on the height data within a predetermined time window prior to the fault.

[0010] Safety control parameters are dynamically calculated based on the operating height, including the upper limit of safe vehicle speed and the upper limit of braking deceleration.

[0011] The vehicle is controlled according to the aforementioned safety control parameters.

[0012] Optionally, the reasonable range for the dynamically calculated rate of change of height includes:

[0013] After the vehicle is powered on, the calibration procedure is automatically executed. By controlling the vehicle to perform standard lifting and lowering actions at multiple predefined speed ranges, the height change rate corresponding to each predefined speed range is recorded.

[0014] Perform statistical analysis on the recorded height change rate, and calculate the average height change rate and standard deviation of the height change rate for each predefined speed segment;

[0015] Based on the average height change rate and the standard deviation of the height change rate, and combined with the safety factor threshold set according to the system misjudgment rate requirements, a reasonable range of height change rate for each predefined speed segment is dynamically generated.

[0016] Optionally, the automatic calibration procedure includes:

[0017] After the vehicle is powered on, it automatically enters the calibration ready state and monitors the input of operation instructions from the monitoring system;

[0018] The calibration procedure is automatically started if no work instruction is detected for a predetermined period of time.

[0019] If a work instruction is received during the calibration procedure, the calibration process is immediately paused and the current calibration status is stored.

[0020] Once the task is completed, the system will automatically resume execution of any unfinished calibration procedures from the stored calibration status points.

[0021] Optionally, the reasonable range for the height change rate of each predefined speed segment dynamically generated includes:

[0022] The standard deviation of the height change rate for each predefined speed segment was calculated using an unbiased variance calculation method.

[0023] Based on the average height change rate and the standard deviation of the height change rate, combined with the safety factor threshold, the upper and lower limits of the reasonable range of the height change rate for each predefined speed segment are dynamically generated;

[0024] The upper limit of the reasonable range of height change rate is obtained by adding the average height change rate to the product of the safety factor threshold and the standard deviation of the height change rate, and the lower limit of the reasonable range of height change rate is obtained by subtracting the product of the safety factor threshold and the standard deviation of the height change rate from the average height change rate.

[0025] Optionally, when monitoring the current operating speed in real time during vehicle operation, if the current operating speed does not belong to any predefined speed segment, the reasonable range of the height change rate corresponding to the current operating speed is dynamically calculated based on the reasonable range of the height change rate of adjacent predefined speed segments using a linear interpolation method.

[0026] Optionally, determining the working height based on height data within a predetermined time window before failure includes:

[0027] Smooth the height data within the predetermined time window before failure;

[0028] The working height before failure is dynamically determined based on the smoothed height data.

[0029] The predetermined time window is dynamically set based on the vehicle data sampling frequency and system response time.

[0030] Optionally, during vehicle braking, the braking method is selected based on the comparison result between the working height before failure and the set height threshold.

[0031] When the working height before failure is higher than the set height threshold, regenerative braking is used, and the actual braking deceleration generated by regenerative braking is controlled not to exceed the upper limit of braking deceleration.

[0032] When the working height before failure is lower than or equal to the set height threshold, mechanical braking is applied, and the actual braking deceleration generated by the mechanical braking is controlled not to exceed the upper limit of the braking deceleration.

[0033] The set height threshold is determined based on the vehicle's stability requirements at its highest operating height.

[0034] Optionally, the dynamically calculated security control parameters include:

[0035] Establish a decreasing relationship between working height and upper limit of safe speed, wherein the upper limit of safe speed decreases as working height increases, and the upper limit of safe speed is not less than a preset minimum safe speed threshold.

[0036] Establish a decreasing relationship between working height and upper limit of braking deceleration, wherein the upper limit of braking deceleration decreases as working height increases, and the upper limit of braking deceleration is not less than a preset minimum braking deceleration threshold.

[0037] The minimum safe speed threshold and the minimum braking deceleration threshold are determined based on the vehicle's stability requirements at its highest operating height.

[0038] Optionally, controlling the vehicle based on safety control parameters includes:

[0039] After determining that the height sensor has failed, control the vehicle's operating speed to not exceed the safe speed limit.

[0040] When braking is required, the actual braking deceleration is controlled to not exceed the upper limit of the braking deceleration.

[0041] Optionally, after determining that the height sensor has failed, the rate of change of the height of the height sensor can be continuously monitored;

[0042] Set a sensor recovery confirmation time threshold. When the height change rate is continuously within the reasonable range within the recovery confirmation time threshold, it is determined that the height sensor has recovered to normal. At this time, stop controlling the vehicle according to the safety control parameters and restore the vehicle to its original operating state.

[0043] In summary, this application includes the following beneficial technical effects:

[0044] 1. This application effectively solves the problem of false alarms and missed alarms caused by existing technologies relying on static thresholds, which cannot adapt to changes in vehicle load, mechanical wear, and hydraulic characteristic drift. By automatically executing a calibration program after the vehicle is powered on, the application controls the vehicle to perform standard lifting and lowering actions at multiple predefined speed ranges. The application statistically analyzes the average value and standard deviation of the height change rate of each predefined speed range, and dynamically generates a reasonable range of height change rate for each predefined speed range by combining it with a safety factor threshold. For non-predefined speed ranges, a corresponding reasonable range is calculated using a linear interpolation method. This ensures that the reasonable range of height change rate is accurately matched with the real-time operating conditions of the vehicle, reducing the false alarm rate and missed alarm rate of the height sensor and significantly improving the reliability of failure detection.

[0045] 2. This application addresses the problem in existing technologies where the last valid height is used as the height benchmark after failure, which is susceptible to fluctuations in instantaneous data, leading to height determination errors. When determining the failure of a height sensor, the application extracts the height data within a predetermined time window before failure and performs two sliding average smoothing processes to eliminate instantaneous interference caused by vehicle vibration and hydraulic system pressure fluctuations. This ensures that the error between the determined working height before failure and the actual working height is ≤2mm, providing a reliable benchmark for subsequent dynamic calculation of safety control parameters. This avoids errors in safety control parameter calculation due to height determination errors, reducing the risk of vehicle rollover and cargo tipping.

[0046] 3. This application addresses the problem that existing technologies using fixed safety control parameters after sensor failure cannot adapt to the safety requirements of different operating heights. Based on the determined operating height before failure, it establishes a decreasing relationship between the operating height and the upper limit of safe vehicle speed and the upper limit of braking deceleration. The higher the operating height, the lower the upper limit of safe vehicle speed and the upper limit of braking deceleration. Furthermore, it sets minimum safe vehicle speed thresholds and minimum braking deceleration thresholds to ensure vehicle mobility and braking effectiveness, making the safety control parameters accurately matched to the operating height. Compared with the fixed parameters in existing technologies, this effectively reduces the lateral tipping moment of the vehicle and the tipping moment of the cargo at high operating heights, thereby improving the safety of vehicle operation after sensor failure.

[0047] 4. This application addresses the problems of existing technologies where mechanical braking, when used uniformly after sensor failure, easily leads to cargo tipping due to instantaneous impact at high operating heights, and insufficient braking response affecting efficiency at medium and low operating heights. It selects the braking method based on a comparison between the operating height before failure and a set height threshold. When the operating height before failure is higher than the set height threshold, regenerative braking is used to avoid mechanical impact; when it is lower than or equal to the set height threshold, mechanical braking is used to ensure braking response speed. Simultaneously, it controls the actual braking deceleration to not exceed the upper limit of braking deceleration, ensuring braking deceleration fluctuation ≤0.1m / s², thus balancing the safety and efficiency of braking at different operating heights.

[0048] 5. This application addresses the problem that existing calibration procedures may interfere with normal operating procedures. After the vehicle is powered on, it automatically enters a calibration-ready state, continuously monitors the input of operating instructions, and automatically starts the calibration procedure if no operating instruction is detected for a predetermined period of time. If an operating instruction is received during the calibration procedure, the calibration is immediately paused and the current calibration state is stored. The calibration is resumed from the stored state after the operation is completed, ensuring that the calibration procedure does not interrupt normal operation and improving vehicle operating efficiency while ensuring the integrity of the calibration. Attached Figure Description

[0049] Figure 1 It is the overall logical flowchart of the method;

[0050] Figure 2 This is a flowchart for dynamically calculating the reasonable range of the rate of change of height;

[0051] Figure 3 This is a flowchart for real-time monitoring and determination of height sensor failure;

[0052] Figure 4 It is a flowchart for determining the working height based on the height data before failure;

[0053] Figure 5 It is a flowchart for dynamically calculating safety control parameters;

[0054] Figure 6It is a flowchart for controlling the vehicle based on safety control parameters;

[0055] Figure 7 This is a flowchart of monitoring the sensor recovery status and exiting the safety control mode. Detailed Implementation

[0056] The following is in conjunction with the appendix Figure 1-7 This application will be described in further detail.

[0057] This application discloses a method for detecting and handling the failure of a height sensor. For example... Figure 1 As shown, a method for detecting and handling height sensor failures is presented. The core logic involves automatically and dynamically calibrating the vehicle upon power-up to generate a reasonable range of height change rates that matches the vehicle's characteristics. During vehicle operation, the method monitors the operating speed and height change rate in real time to accurately determine the sensor's failure state. Based on the effective height data before failure, the operating height is determined, and safety control parameters adapted to this height are dynamically calculated. Closed-loop control of vehicle speed and braking is implemented based on these safety control parameters. Simultaneously, continuous monitoring of the sensor status enables mode switching after recovery. This method ultimately solves the technical defects of existing technologies, such as reliance on static thresholds leading to false positives and false negatives, unreasonable safety strategies after failure, and calibration affecting operating efficiency. It ensures vehicle operating safety and efficiency without increasing hardware costs. The specific execution process of each step is described in detail below in chronological order.

[0058] S1. Reasonable range for dynamic calculation of height change rate

[0059] like Figure 2 and Figure 3 As shown, the core purpose of this step is to generate a reasonable range of height change rate that matches the vehicle's real-time load status, mechanical wear degree, and hydraulic characteristics through the automatic calibration program after the vehicle is powered on, replacing the static threshold of the existing technology, and providing an accurate benchmark for subsequent height sensor failure determination.

[0060] S11. Perform automatic calibration procedure.

[0061] After the vehicle is powered on, the vehicle control system automatically enters the calibration-ready state while continuously monitoring the input of system operation commands. The vehicle control system is set to a "preset duration" of 30 seconds. According to statistics from the high-bay picking industry, the response interval for operators issuing operation commands is typically 10-20 seconds. The 30-second setting avoids accidental calibration initiation due to brief periods without commands, while ensuring timely calibration when there is no actual work requirement, thus balancing calibration timeliness with the avoidance of operational interference.

[0062] If the vehicle control system does not detect a work instruction within 30 seconds, the vehicle automatically initiates the calibration procedure. During the calibration procedure, if the vehicle control system receives a work instruction, the vehicle immediately pauses the calibration process and stores the current calibration status, including key information such as completed predefined speed segments and recorded altitude change rate data. Once the work task is completed, the vehicle automatically resumes the incomplete calibration procedure from the stored calibration status point, ensuring that the calibration does not interrupt the normal work process and improving work efficiency while guaranteeing calibration integrity.

[0063] S12. Record the rate of change of altitude for each predefined speed segment.

[0064] During the calibration procedure initiated by S11, the vehicle control system first determines three predefined speed ranges, namely low lift speed... (i.e., 30% of the rated lifting speed), medium lifting speed (i.e., 60% of the rated lifting speed), high lifting speed (i.e., 100% of the rated lifting speed). The reason for selecting three speed ranges and dividing them into 30%, 60%, and 100% is as follows: Based on the statistical distribution of high-level picking vehicle operation speeds, operation scenarios with speeds ≤30% of the rated lifting speed account for 25%, scenarios with speeds between 30% and 60% of the rated lifting speed account for 55%, and scenarios with speeds >60% of the rated lifting speed account for 20%. This division can cover more than 95% of actual operation scenarios, ensuring that the reasonable range generated subsequently can adapt to the vast majority of working conditions.

[0065] Subsequently, the vehicle control system directs the vehicle to execute standard lifting and lowering maneuvers in the sequence of "low lifting speed → medium lifting speed → high lifting speed". During the lifting process at each speed range, the height sensor collects height data at a sampling frequency of 10Hz; the vehicle control system calculates the height change rate of the lifting action at that speed range using the formula "height change rate = height change amount / time interval". Similarly, during the lowering process at each speed range, the height sensor collects height data at the same sampling frequency, and the vehicle control system repeats the above calculation to obtain the height change rate of the lowering action at that speed range, providing accurate basic data for subsequent statistical analysis.

[0066] S13, Statistical analysis of height change rate data

[0067] After S12 completes the recording of the height change rate for each predefined speed segment, the vehicle control system performs statistical analysis on the change rate data for each speed segment.

[0068] The vehicle control system first calculates the average rate of change of height for each predefined speed range. ,in Corresponding to low lifting speed medium lifting speed High lifting speed The calculation method is as follows:

[0069]

[0070] The reason for choosing this calculation method is that the direction of the hydraulic driving force is different during the lifting and lowering process, which may lead to a slight difference in the rate of change. Taking the average value can offset the directional error and ensure the representativeness of the data.

[0071] Next, the vehicle control system uses an unbiased variance calculation method to calculate the standard deviation of the height change rate for each predefined speed range. Because only two rate of change data (climbing and descent) are collected for each speed segment (sample size) If ordinary variance is used (denominator is...), The calculation may underestimate the true range of fluctuation in the sample population. Unbiased variance is corrected by adjusting the denominator to " To eliminate this bias, the formula is derived as follows:

[0072]

[0073] In the formula, For the first The first speed segment Data on the rate of change of height ( The time is the rate of change of rise. (When the rate of change is decreasing) The rate of change data for this velocity range (here) , For the first The average height change rate for each speed range is calculated. By measuring the average and standard deviation, the vehicle control system can accurately capture the "center value" and "natural fluctuation range" of the height change rate for each speed range, providing scientific data support for defining a reasonable range subsequently.

[0074] S14. Dynamically generate a reasonable range for the height change rate of each predefined speed segment.

[0075] The average value obtained based on S13 with standard deviation Vehicle control systems introduce safety factor thresholds Safety threshold here The value is set to 1.5. The reason for choosing 1.5 is: through Monte Carlo simulation analysis (based on 1000 sets of height change rate data under different loads and wear conditions), when... At that time, the rate of change of height exceeded " The probability of the error range is ≤0.1%, which fully meets the safety requirement of "false fault rate ≤0.1%" for high-level picking vehicles; if The false positive rate rises to 3%-5%; if The false negative rate increased to 1.2%, and 1.5 is the optimal value that balances false positives and false negatives.

[0076] Subsequently, the vehicle control system calculates the reasonable range of the rate of change of height for each predefined speed segment:

[0077] Upper limit of reasonable range: That is, the product of the average value, the safety factor, and the standard deviation represents the maximum reasonable value of the rate of change of height in that speed range;

[0078] Lower limit of reasonable range: That is, the product of the average value and the safety factor and the standard deviation, which represents the minimum reasonable value of the rate of change of height in that speed range.

[0079] This reasonable range is strongly tied to the vehicle's current state. For example, when the vehicle is fully loaded, the increased load on the lifting mechanism leads to a decrease in the lifting change rate, and the average value... As the threshold decreases, the reasonable range is adjusted accordingly, completely resolving the shortcomings of the static threshold in existing technologies. Existing technologies with fixed thresholds (such as uniformly set at 8 mm / s) are prone to misjudging a normal low rate of change of 5 mm / s as a failure under full load, and are prone to missing an abnormally high rate of change of 10 mm / s as normal under heavy load and rapid descent. The dynamic range of this step can accurately match the real-time operating conditions, avoiding misjudgment and missed judgment.

[0080] S15. Calculate the reasonable range of height change rate for non-predefined speed segments.

[0081] After S14 completes the generation of a reasonable range for the predefined speed segment, the vehicle may experience a change in the current operating speed during actual operation. In cases where the current operating speed does not fall within any predefined speed range (e.g., the current operating speed is 45% of the rated lifting speed, falling between 30% of the low lifting speed and 60% of the medium lifting speed), it is necessary to calculate the reasonable range of the current speed based on the predefined range in S14. Otherwise, a detection blind spot will occur. Therefore, this step is based on the results of S14.

[0082] The vehicle control system uses a linear interpolation method for calculation, and the specific process is as follows:

[0083] 1. Determine adjacent predefined speed segments: Find the current operating speed. Two adjacent predefined speed segments (such as and Extract the upper limit of the reasonable range for these two speed segments (denoted as ), respectively. ) and lower limit (denoted as respectively) );

[0084] 2. Derivation of the linear interpolation formula: Through actual vehicle testing, it was verified that the reasonable range of speed and height change rate is linearly correlated between adjacent predefined speed segments (for every 1% increase in rated lifting speed, the upper / lower limit of the reasonable range changes linearly by 0.05 mm / s). Therefore, based on the formula "speed difference ratio = range difference ratio", the following formula is derived:

[0085] The upper limit of the reasonable range corresponding to the current speed:

[0086]

[0087] The lower limit of the reasonable range corresponding to the current speed:

[0088]

[0089] This operation achieves full coverage of all reasonable operating speeds, avoiding the problem of missed detection caused by speed blind spots (such as the 30%-60% rated lifting speed range) in existing technologies, increasing the coverage of failure detection from 95% to 100%, and further improving detection accuracy.

[0090] S2. Real-time monitoring and determination of height sensor failure.

[0091] like Figure 3 As shown, the core purpose of this step is to accurately determine whether the height sensor has failed, based on the reasonable range of the height change rate dynamically generated by S1 and combined with real-time data during vehicle operation.

[0092] S21. Real-time monitoring of current operating speed and altitude change rate.

[0093] Once the vehicle enters normal operating mode, the vehicle control system continuously collects two key parameters at a fixed frequency to ensure the real-time nature, accuracy, and comparability of the monitoring data.

[0094] S211, Collect current operation speed

[0095] The vehicle control system collects the real-time speed of the vehicle's drive motor through a speed sensor, and then accurately calculates the current operating speed based on the fixed transmission ratio of "motor speed - operating speed" calibrated at the vehicle's factory. The transmission ratio is an inherent parameter of the vehicle's mechanical structure, with a conversion error ≤0.5%, which meets the speed accuracy requirements for failure determination. The sampling frequency is set to 10Hz, which is completely consistent with the sampling frequency of the height sensor in S12. 10Hz was chosen because this frequency is the industry standard for data sampling in industrial vehicles. It ensures that the speed data is updated every 0.1s, meeting the timeliness requirements for real-time determination, while avoiding increasing the controller's computational load and preventing system lag due to excessively high sampling frequencies (such as 20Hz).

[0096] S212. Calculate the rate of change of current altitude.

[0097] The height sensor continuously collects height data of the forks or work platform at a sampling frequency of 10Hz. The vehicle control system then converts two consecutive height data collections (denoted as...) into... and , Substituting the current sampling time into the calculation formula:

[0098]

[0099] in, The sampling time interval (since the sampling frequency is 10Hz, therefore...) This calculation method is completely consistent with the standard "altitude change rate = altitude change amount / time interval" in S12, ensuring that the change rate data in this step has the same calculation benchmark as the change rate data in the S1 calibration stage, and avoiding judgment deviations caused by differences in calculation logic.

[0100] S22. Compare and determine the failure status of the height sensor.

[0101] The vehicle control system first completes the matching of "current operating speed - reasonable range", and then achieves accurate determination of failure state by comparing the real-time rate of change with the reasonable range.

[0102] S221. Match the reasonable range of the rate of change of height corresponding to the current speed.

[0103] The vehicle control system will collect the current operating speed from S211. Compare with the predefined speed range defined in S12:

[0104] like Rated lifting speed, determine that it belongs to The vehicle control system directly retrieves the data generated by S14 for the corresponding predefined speed range. A reasonable range for the rate of change of height;

[0105] like Rated lifting speed, determine that it belongs to The corresponding predefined speed range is retrieved from S14. Exclusive and reasonable scope;

[0106] like Rated lifting speed, determine that it belongs to The corresponding predefined speed range is retrieved from S14. Exclusive and reasonable scope;

[0107] like Between two predefined speed ranges (e.g., 45% of the rated lifting speed, between...) and Between (the two points), the vehicle control system retrieves the "reasonable range of the current speed-specific height change rate" calculated by linear interpolation from S15 to ensure there are no speed blind spots.

[0108] S222, Compare and determine the sensor status

[0109] The vehicle control system will calculate the current altitude change rate using S212. Compare with the reasonable range of height change rate matched by S221:

[0110] like or The vehicle control system determined that the height sensor had failed.

[0111] like If the height sensor is within the range of "lower limit of reasonable range to upper limit of reasonable range", the vehicle control system determines that the height sensor is in normal condition.

[0112] This judgment logic is precisely adapted to the dynamic operating conditions of the vehicle, completely solving the core defects of existing technologies: existing technologies use a fixed threshold (such as uniformly set to 8mm / s) for judgment, when the vehicle is moving at... During operation at 100% rated lifting speed, the normal height change rate can reach 10mm / s. Because this does not exceed a fixed threshold, it is often missed as "normal," creating a potential safety hazard. When the vehicle... During operation, the normal height change rate is only 5mm / s, which is below a fixed threshold and is therefore mistakenly judged as "failure," incorrectly triggering the safety mode and impacting efficiency. This step, however, precisely binds the "speed-range" parameters, ensuring the judgment result perfectly matches the vehicle's actual operating state. Combined with S1's dynamic calibration logic, this ultimately reduces the height sensor's false positive rate from 3%-5% in existing technologies to below 0.1%, and the false negative rate to below 0.05%, significantly improving the reliability of failure detection.

[0113] S3. Determine the working height based on the height data before failure.

[0114] like Figure 4 As shown, the core purpose of this step is to accurately determine the actual working height by extracting and processing the height data before the failure after S2 determines that the height sensor has failed, so as to provide a reliable benchmark for subsequent calculation of safety control parameters.

[0115] S31. Extract height data within the predetermined time window before failure.

[0116] The vehicle control system immediately initiates the height data extraction process prior to failure the instant the height sensor failure determination result is output in S2. The vehicle control system sets the "pre-determined time window before failure" to 3 seconds. On the one hand, combined with the unified 10Hz data sampling frequency in S12 and S21, 3 seconds can collect 30 consecutive height data points, which is sufficient to offset the random error of a single data point. On the other hand, referring to the 0.5-second system response time of high-level picking vehicles in the industry, the 3-second window length can completely cover the stable operation phase before sensor failure, avoiding the inclusion of abnormal data in the failure transition phase (usually <0.5 seconds) in the extraction range, and ensuring that all extracted data are valid data from when the sensor is working normally.

[0117] Subsequently, the vehicle control system uses the failure determination time as the end point and extracts all 30 raw height data collected by the height sensor within the previous 3 seconds in a time-backtracking order, completely preserving the height change trend before the failure, and providing a complete data foundation for subsequent smoothing processing.

[0118] S32. Smooth the height data.

[0119] The vehicle control system employs a moving average method, commonly used in industrial data noise reduction, to smooth the 30 original height data points extracted by S31. This method requires no new hardware or complex algorithms; it is implemented solely through software logic, thus incurring no additional hardware costs. The specific operation process is as follows:

[0120] The vehicle control system arranges the 30 altitude data points in chronological order of collection time (denoted as...). , For the earliest data collection, (This is the last data collected before it became invalid).

[0121] Set the sliding window size to 5 data points and the sliding step size to 1, meaning the first window contains the data. The second window contains data. This continues until the 26th window contains data. A total of 26 preliminary smoothing data points were generated;

[0122] To further eliminate residual fluctuations, the vehicle control system performs a sliding average process with the same parameters (5 data points in the window, step size 1) on the above 26 preliminary smoothed data, and finally generates 22 secondary smoothed data.

[0123] The vehicle control system calculates the arithmetic mean of these 22 quadratic smoothed data points to obtain a stable mean height data value, which is the effective height reference value after eliminating instantaneous fluctuations.

[0124] The reason for using the moving average method and performing two smoothing processes is that, in actual operation, the height sensor may experience instantaneous data fluctuations of ±1mm due to factors such as vehicle vibration and hydraulic system pressure fluctuations. These fluctuations do not reflect the actual changes in working height. If the raw data is used directly, it may lead to errors in the determination of working height, such as misjudging a 900mm actual height as 898mm or 902mm. By performing two moving average processes, instantaneous interference can be filtered layer by layer, ensuring that the processed data can truly reflect the stable working height before failure, thus ensuring the accuracy of subsequent height determination.

[0125] S33. Determine the working height before failure.

[0126] The vehicle control system dynamically determines the average height data obtained from S32 as the "operating height before failure". The "dynamic determination" here means that if the vehicle is in a slow lifting or lowering state before the failure (e.g., lifting speed of 5mm / s, height change of 15mm within 3 seconds), the average value after two moving averages will be adjusted according to the actual height change trend, rather than taking data from a fixed moment, to ensure... It can accurately reproduce the actual working height at the moment of sensor failure.

[0127] This method was determined through actual vehicle verification. The error between the actual operating height and the sensor's height at the moment of failure is ≤2mm, far superior to existing technologies. Existing technologies typically use the "last effective height" as the height benchmark after failure. If the last effective height fluctuates to 889mm (actual height is 900mm), it will lead to an underestimation of the height by 11mm, resulting in an overestimation of the subsequent safe speed limit calculation. For example, a speed that should be 2km / h might be mistakenly calculated as 2.2km / h, increasing the risk of vehicle rollover. This new process, through "complete data extraction + two smoothing processes," completely avoids the impact of a single data fluctuation, making... It can accurately reflect the actual operating height, laying a reliable foundation for subsequent dynamic calculation of safety control parameters, and improving the safety of vehicle control after sensor failure from the source.

[0128] S4. Dynamically calculate safety control parameters

[0129] like Figure 5 As shown, the core objective of this step is to determine the pre-failure working height based on S3. The system dynamically calculates and adapts the safety control parameters (safe speed limit and braking deceleration limit) to the altitude, providing a scientific basis for subsequent vehicle speed and braking control.

[0130] S41. Establish and calculate the safe speed limit.

[0131] S411. Establish a decreasing relationship between working height and the upper limit of safe speed.

[0132] The vehicle control system first establishes a decreasing relationship between the operating height and the upper limit of the safe speed. This relationship is based on the mechanical characteristics of the high-bay order picker: the higher the operating height, the higher the vehicle's center of gravity (including the cargo), and the greater the lateral tipping moment at the same speed, making it easier to exceed the stability limit and cause a rollover. This was verified through real-vehicle testing of a certain type of high-bay order picker (maximum operating height 1200mm): when... (Maximum operating height of the vehicle) At speeds exceeding 1 km / h, the lateral rollover moment can exceed 90% of the rated stabilizing moment, posing a significant risk of rollover. At the lowest operating height, the vehicle speed can be increased to 5km / h while still ensuring a braking distance of ≤2m, which meets the safety limit for braking distance in the "Safety Requirements for Industrial Vehicles" (GB / T10827.1).

[0133] S412, Setting safe vehicle speed related thresholds

[0134] The vehicle control system sets two key thresholds:

[0135] Minimum safe speed threshold The reason for choosing 1 km / h is that, At this speed, the lateral rollover moment of the vehicle is only 80% of the rated stable moment, and the braking distance is only 0.4m, which can completely offset the risk of rollover, while ensuring that the vehicle has the ability to move slowly, which is convenient for operation adjustment or rescue.

[0136] Minimum operating height and maximum safe speed The reason for choosing 5km / h is that... At this speed, the vehicle's braking distance is approximately 1.5m (calculated based on a braking deceleration of 2m / s²), which meets the mobility efficiency requirements for low-position operations without exceeding the safe braking distance limit of 2m.

[0137] S413, Derive the formula for the upper limit of safe vehicle speed and calculate...

[0138] Since the upper limit of safe vehicle speed needs to decrease linearly with H_f, and two boundary conditions must be met ( ; hour The derivation formula for the vehicle control system is as follows:

[0139] Calculate the height difference ratio: This ratio reflects the difference between the current working height and the highest possible height. The formula is as follows: , The larger the value, the smaller the ratio, and the closer it is to the upper limit of safe speed. ;

[0140] Calculate the speed increment: The speed increment is the product of the "difference between the minimum and minimum safe speeds" and the "proportion of the height difference", as shown in the formula. ;

[0141] Determining the upper limit of safe speed: The upper limit of safe speed is the sum of the minimum safe speed threshold and the speed increment. The final formula is:

[0142]

[0143] In the formula, The maximum safe speed limit after failure (unit: km / h). The maximum operating height of the vehicle is 1200mm, based on the design parameters of this type of high-bay picking vehicle. The working height before failure determined for S3 (unit: mm).

[0144] S414, Verify the reasonableness of the safe speed limit.

[0145] by ( Taking 75% as an example, the vehicle control system is substituted into the formula for calculation:

[0146]

[0147] At this speed, the vehicle's braking distance is approximately 0.8 meters, and the lateral rollover moment is 85% of the rated stable moment, posing no risk of rollover. After existing technology becomes obsolete, the vehicle speed will be uniformly set at 3 km / h. At that time, the braking distance reached 1.2m, and the lateral rollover moment approached 95% of the rated stabilizing moment, significantly increasing the risk of rollover; however, the dynamic calculation in this step... and Precise adaptation effectively mitigates this risk. Simultaneously, the vehicle control system ensures [safety / security] through logical judgment. ,avoid The vehicle was unable to move due to excessively low speed.

[0148] S42. Establish and calculate the upper limit of braking deceleration.

[0149] S421. Establish a decreasing relationship between working height and the upper limit of braking deceleration.

[0150] The vehicle control system establishes a decreasing relationship between operating height and the upper limit of braking deceleration. This relationship is based on cargo stability requirements: the higher the operating height, the higher the center of gravity of the cargo, and the greater the overturning moment generated by the cargo due to inertia during braking. Sudden braking can easily lead to cargo overturning. This is verified through mechanical analysis and real-vehicle testing: when... When braking deceleration exceeds 0.5 m / s², the tipping moment of the cargo on the forks will exceed 10% of the rated anti-tipping moment, reaching the danger threshold; when When the braking deceleration reaches 2m / s², the cargo overturning moment is only 5% of the rated anti-overturning moment, and the braking distance is ≤2m, which meets the safety requirements.

[0151] S422, Set braking deceleration related thresholds

[0152] The vehicle control system sets two key thresholds:

[0153] Minimum braking deceleration threshold The reason for choosing 0.5 m / s² is that, At this deceleration, the cargo overturning moment is 8% of the rated anti-overturning moment, which is less than the dangerous threshold of 10%, and it can ensure that the vehicle can decelerate from a speed of 1 km / h to a standstill within 5 seconds, thus meeting the braking effectiveness requirements.

[0154] Minimum operating height and maximum braking deceleration The reason for choosing 2m / s² is that, At this deceleration, the braking distance at a vehicle speed of 5 km / h is approximately 1.5 m, which satisfies the efficiency requirements for rapid braking without causing the cargo to tip over.

[0155] S423. Derive the formula for the upper limit of braking deceleration and calculate...

[0156] Following the derivation logic of the safe speed limit, the braking deceleration limit must be... Linearly decreasing, and satisfying boundary conditions ( hour ; hour The derivation formula for the vehicle control system is as follows:

[0157] Use the height difference ratio This reflects the degree to which the current altitude affects the braking deceleration;

[0158] Calculate the deceleration increment: The deceleration increment is the product of the "difference between minimum and minimum braking deceleration" and the "ratio of height difference", as shown in the formula. ;

[0159] Determine the upper limit of braking deceleration: The upper limit of braking deceleration is the sum of the minimum braking deceleration threshold and the deceleration increment. The final formula is:

[0160]

[0161] In the formula, The maximum braking deceleration after failure (unit: m / s²). The maximum working height of the vehicle is 1200mm. The working height before failure (unit: mm).

[0162] S424. Verify the rationality of the upper limit of braking deceleration.

[0163] by ( Taking 50% as an example, the vehicle control system is substituted into the formula for calculation:

[0164]

[0165] At this deceleration, the cargo overturning moment is 7% of the rated anti-overturning moment, and the braking distance is approximately 1.0m, balancing safety and efficiency. After existing technology fails, the braking deceleration is uniformly set at 1.0m / s². At a speed of 5 km / h, the braking distance reaches 2.3 m, exceeding the safety limit of 2 m; when At that time, the cargo overturning moment reached 9.5% of the rated anti-overturning moment, approaching the dangerous threshold; however, the dynamic calculation in this step can completely avoid these problems. Simultaneously, the vehicle control system ensures... ,avoid The braking deceleration is too low, causing the braking to be ineffective.

[0166] This step dynamically generates safety control parameters using a linear decreasing model, ensuring a highly accurate match between the safety strategy and the pre-failure operation. Compared to the fixed parameters of existing technologies, this reduces the risk of vehicle instability and cargo rollover after sensor failure, significantly improving operational safety.

[0167] S5. Control the vehicle based on safety control parameters.

[0168] like Figure 6 As shown, the core objective of this step is to calculate the safe speed limit in S4. With upper limit of braking deceleration Then, through precise control of vehicle speed and braking system, closed-loop safe operation is achieved after sensor failure.

[0169] S51. Control the vehicle's operating speed to not exceed the safe speed limit.

[0170] S511, Continuously collect current vehicle speed

[0171] The vehicle control system uses the same acquisition logic as the S211. It obtains the motor speed in real time through the drive motor's speed sensor and combines it with the fixed transmission ratio of "motor speed - operating speed" calibrated at the factory (this transmission ratio is an inherent parameter of the mechanical structure, with a conversion error ≤0.5%) to accurately calculate the current vehicle operating speed. The sampling frequency is maintained at 10Hz, consistent with the sampling frequencies of S12 and S21, ensuring that the vehicle speed data is updated every 0.1s, providing a real-time and accurate input signal for subsequent speed control.

[0172] S512, Speed ​​adjustment based on safe vehicle speed limit

[0173] The vehicle control system will collect data in real time. Calculated with S41 Perform millisecond-level comparisons and implement differential control based on the comparison results:

[0174] like The vehicle control system immediately sends a slow-deceleration command to the drive motor, gradually reducing the motor's output power, with each adjustment increment ≤5% of the rated power, so that... Smoothly decreased The total duration of the deceleration process is strictly controlled to be ≥2s. The reason for choosing 2s is: For example, a deceleration time of 2 seconds can make the average deceleration ≤0.5km / h / s (equivalent to 0.14m / s²), which is far below the cargo sway threshold (usually 0.3m / s²), effectively preventing the cargo from swaying violently;

[0175] like The vehicle control system maintains the current motor output power to keep the vehicle speed, while simultaneously sending a limiting command to the accelerator pedal module to prohibit any actions that could cause the accelerator pedal to malfunction. Exceed Acceleration maneuvers are used to ensure that the vehicle speed remains within a safe range.

[0176] For example, when At that time, S41 calculated If at this time The motor output power gradually decreases from 60% to 30% of the rated power, and the vehicle speed smoothly drops to 2km / h within 2 seconds, with the cargo swaying amplitude ≤2cm. In contrast, existing technology usually forces a rapid deceleration to 1km / h after sensor failure, regardless of the current height, which can easily lead to a sudden drop in vehicle speed and cargo swaying amplitude of more than 10cm. The speed control method in this step significantly improves cargo stability and operational comfort.

[0177] S52. Select braking mode and control braking deceleration based on working height.

[0178] S521, Set the height threshold

[0179] The vehicle control system is set to a "set height threshold" of 300mm. The reason for choosing 300mm is that, through real vehicle testing, the operating height before failure has been verified. When the vehicle's center of gravity (including the cargo) is 300mm above the fork reference plane, the instantaneous impact of mechanical braking can easily cause the cargo to tip over; At this time, the vehicle's center of gravity is low, and the rapid response of the mechanical brakes can meet the operational efficiency requirements, with a rollover risk of ≤5%. This threshold is set entirely based on the vehicle's stability requirements at its highest operating height, and is a critical value for balancing braking safety and efficiency.

[0180] S522. Select braking method according to working height.

[0181] The vehicle control system will determine the pre-failure working height as specified by S33. Compare the braking method with the 300mm height threshold setting and select the appropriate braking method:

[0182] like The vehicle control system selects regenerative braking. Regenerative braking converts the vehicle's kinetic energy into electrical energy by switching the drive motor to a generator. The braking process is free of mechanical friction and impact, and the deceleration change slope is ≤0.2m / s³, which can achieve smooth braking and effectively reduce the risk of cargo tipping over during high-altitude operations.

[0183] like The vehicle control system selects mechanical braking. Mechanical braking generates braking force through the friction between the brake shoes and the brake drum, with a response time of less than 0.3 seconds, which is 0.2 seconds faster than regenerative braking. It can meet the requirements of "rapid braking and shortened braking distance" when operating at low to medium heights. Moreover, the vehicle's center of gravity is low at this time, and the braking impact will not cause the cargo to tip over.

[0184] S523, Control the actual braking deceleration to not exceed the upper limit.

[0185] Regardless of whether regenerative braking or mechanical braking is used, the vehicle control system collects the actual braking deceleration in real time through a brake pressure sensor. (Sampling frequency 10Hz), and compared with the results calculated by S42 Perform real-time comparisons and execute closed-loop control:

[0186] like The vehicle control system sends a pressure regulation command to the braking actuator. Regenerative braking reduces power generation, while mechanical braking reduces air (or hydraulic) pressure in the braking circuit. Smoothly decreased The adjustment accuracy is ≤0.1m / s².

[0187] like The vehicle control system maintains the current braking pressure to ensure that the braking process meets safety requirements while avoiding inefficiency caused by excessive braking.

[0188] For example, when At that time, S42 calculated The vehicle control system selects regenerative braking, which adjusts the power generation in real time to... Stable control at 0.5 m / s², the cargo tipping force is only 5% of the rated load; when hour, Select mechanical braking, and control the air pressure in the braking circuit to... Maintaining a speed of 2 m / s², the braking distance is approximately 1.5 m, which meets industry safety standards.

[0189] In existing technologies, mechanical braking is uniformly employed when sensors fail, with a deceleration fluctuation range of ±0.5 m / s². At that time, the actual deceleration may reach 1.0 m / s², and the cargo tipping force may exceed 10%; however, this step, through "height-braking mode" matching and deceleration closed-loop control, makes the braking deceleration fluctuation ≤0.1 m / s², and the cargo tipping force ≤8%, significantly improving the operational safety after sensor failure.

[0190] S6. Monitor sensor recovery status and exit safety control mode.

[0191] like Figure 7 As shown, the core purpose of this step is to continuously track the real-time status of the altitude sensor while the S5 performs safety control. When the sensor returns to normal function, the system automatically exits the safety control mode and restores the vehicle to its original operating state.

[0192] S61. Continuously monitor the altitude change rate of the altitude sensor.

[0193] During the execution of S5 safety control, the vehicle control system does not interrupt the acquisition and processing of signals from the height sensor. The monitoring logic is completely consistent with the standard for "height change rate calculation" in S21: the height sensor continuously acquires the height data of the forks or work platform at a sampling frequency of 10Hz, and the vehicle control system converts two adjacent height data acquisitions (denoted as...) into... and Substitute " ( The real-time height change rate is obtained from the calculation formula (determined by a 10Hz sampling frequency). This monitoring method ensures that the calculation benchmark for the rate of change is completely consistent with the S1 calibration stage and the S2 judgment stage, avoiding misjudgments of the state due to differences in calculation logic. At the same time, the 10Hz sampling frequency can meet the requirements of real-time tracking of sensor status without adding extra computational load to the controller, achieving parallel and conflict-free operation of safety control and status monitoring.

[0194] S62. Set the sensor recovery confirmation time threshold and determine the recovery status.

[0195] S621. Set recovery confirmation time threshold.

[0196] The vehicle control system sets the "sensor recovery confirmation time threshold" to 5 seconds. The reason for choosing 5 seconds is that, combined with a sampling frequency of 10 Hz, 5 seconds can collect 50 consecutive height change rate data points, which is sufficient to reflect the stable state of the sensor. In the industry, height sensors are affected by electromagnetic interference, momentary stability of wiring contact, and other factors that generate "false normal signals" that usually last for less than 1 second. The 5-second time threshold can effectively filter out such false signals, avoid misjudging "brief normal" as "complete recovery", and ensure the reliability of recovery determination.

[0197] S622, Determine the sensor recovery status

[0198] The vehicle control system will calculate in real time by S61 The current operating speed is compared with the "reasonable range of height change rate corresponding to the current operating speed" generated by S1 at the millisecond level: if the current operating speed belongs to a predefined speed range (low / medium / high lifting speed), the reasonable range of the corresponding speed range generated by S14 is called; if the current operating speed belongs to a non-predefined speed range, the reasonable range obtained by linear interpolation in S15 is called. If the height sensor remains within a reasonable range for 5 consecutive seconds (i.e., none of the 50 data points exceed the corresponding range), the vehicle control system determines that the height sensor has returned to normal. If any data point exceeds the reasonable range within 5 seconds, the sensor is determined to be in a malfunctioning state, and the current monitoring rhythm continues.

[0199] S63. Exit safety control mode and restore the vehicle to its original operating state.

[0200] If S62 determines that the height sensor has returned to normal, the vehicle control system will immediately perform the following actions:

[0201] Stop limiting based on safety control parameters: Terminate the "speed not exceeding" setting in S5. The speed limit instruction was given, and the braking deceleration was stopped at no more than [a certain value]. "Brake adjustment command;

[0202] Restore vehicle's original operating parameters: For speed control, restore the original power limit of the drive motor, allowing the vehicle speed to rise back to the factory-set rated maximum speed; for braking control, restore the original deceleration setting of the braking system, and at the same time stop the "select braking mode based on working height" logic in S5, and restore the conventional braking control strategy, that is, the default mode of directly using mechanical braking or regenerative braking without distinguishing height.

[0203] If S62 does not determine that the sensor has returned to normal, the vehicle control system will continue to execute the safety control operation of S5 to ensure that the vehicle remains in a "low-risk operating state" until the sensor has been stably restored.

[0204] In existing technologies, after the height sensor recovers, the operator needs to manually restart the vehicle control system to exit the safety mode, resulting in an operation interruption time of 5-10 minutes. This new process, through automatic monitoring and switching, reduces the operation interruption time after the sensor recovers to less than 1 second, significantly improving operational continuity. Furthermore, the entire process requires no new hardware modules, only software logic optimization, meeting the technical requirement of "no increase in hardware costs" and balancing safety and economy.

[0205] The implementation principle of the height sensor failure detection and handling method in this application embodiment is as follows: After the vehicle is powered on, the calibration program is automatically started, and the vehicle is controlled to perform standard lifting and lowering actions at multiple predefined speed segments. The average value and standard deviation of the height change rate of each speed segment are statistically analyzed, and a reasonable range is dynamically generated in combination with the safety factor threshold. Non-predefined speed segments are supplemented and covered by linear interpolation. During operation, the current speed and the corresponding height change rate are monitored in real time. If the speed exceeds the reasonable range, the vehicle is judged to have failed. Then, the actual working height is determined based on the smoothed height data within the predetermined time window before the failure. The upper limit of safe vehicle speed and the upper limit of braking deceleration that decrease with the working height are dynamically calculated. Regenerative braking or mechanical braking is selected according to the working height and closed-loop control is implemented. At the same time, the sensor status is continuously monitored. After the sensor continuously meets the reasonable range for a set time, the original operating state is automatically restored. This application fundamentally solves the problem of false positives and false negatives caused by the reliance on static thresholds in existing technologies. Dynamic calibration adapts to load changes, mechanical wear, and hydraulic characteristic drift, reducing the false positive and false negative rates. Smoothing of height data before failure ensures the accuracy of the working height benchmark and avoids deviations in safety parameter calculations caused by single data fluctuations. Dynamic safety control parameters and height-adapted braking method selection significantly reduce the risk of vehicle instability and cargo tipping at high working heights. The pause and resume functions of the calibration program and the automatic sensor recovery function ensure the integrity of calibration while avoiding interference with work efficiency. Closed-loop safety control after sensor failure can be achieved without adding new hardware, greatly improving the safety and continuity of industrial vehicle operations.

[0206] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for detecting and handling the failure of a height sensor, characterized in that, Includes the following steps: The vehicle is controlled to perform standard lifting and lowering maneuvers at multiple predefined speed ranges, and the reasonable range of the height change rate is dynamically calculated. During vehicle operation, the current operating speed and the corresponding height change rate are monitored in real time. The height change rate is compared with the reasonable range. When the height change rate exceeds the reasonable range, the height sensor is determined to be faulty. When a height sensor is determined to be faulty, the working height is determined based on the height data within a predetermined time window prior to the fault. Safety control parameters are dynamically calculated based on the operating height, including the upper limit of safe vehicle speed and the upper limit of braking deceleration. The vehicle is controlled according to the aforementioned safety control parameters.

2. The method according to claim 1, characterized in that, The reasonable range for the dynamically calculated rate of height change includes: After the vehicle is powered on, the calibration procedure is automatically executed. By controlling the vehicle to perform standard lifting and lowering actions at multiple predefined speed ranges, the height change rate corresponding to each predefined speed range is recorded. Perform statistical analysis on the recorded height change rate, and calculate the average height change rate and standard deviation of the height change rate for each predefined speed segment; Based on the average height change rate and the standard deviation of the height change rate, and combined with the safety factor threshold set according to the system misjudgment rate requirements, a reasonable range of height change rate for each predefined speed segment is dynamically generated.

3. The method according to claim 2, characterized in that, The automatic calibration procedure includes: After the vehicle is powered on, it automatically enters the calibration ready state and monitors the input of operation instructions from the monitoring system; The calibration procedure is automatically started if no work instruction is detected for a predetermined period of time. If a work instruction is received during the calibration procedure, the calibration process is immediately paused and the current calibration status is stored. Once the task is completed, the system will automatically resume execution of any unfinished calibration procedures from the stored calibration status points.

4. The method according to claim 2, characterized in that, The reasonable range for the height change rate of each predefined speed segment dynamically generated includes: The standard deviation of the height change rate for each predefined speed segment was calculated using an unbiased variance calculation method. Based on the average height change rate and the standard deviation of the height change rate, combined with the safety factor threshold, the upper and lower limits of the reasonable range of the height change rate for each predefined speed segment are dynamically generated; The upper limit of the reasonable range of height change rate is obtained by adding the average height change rate to the product of the safety factor threshold and the standard deviation of the height change rate, and the lower limit of the reasonable range of height change rate is obtained by subtracting the product of the safety factor threshold and the standard deviation of the height change rate from the average height change rate.

5. The method according to claim 1, characterized in that, When monitoring the current operating speed in real time during vehicle operation, if the current operating speed does not belong to any predefined speed segment, the reasonable range of the height change rate corresponding to the current operating speed is dynamically calculated based on the reasonable range of the height change rate of adjacent predefined speed segments using a linear interpolation method.

6. The method according to claim 1, characterized in that, Determining the working height based on height data within a predetermined time window before failure includes: Smooth the height data within the predetermined time window before failure; The working height before failure is dynamically determined based on the smoothed height data. The predetermined time window is dynamically set based on the vehicle data sampling frequency and system response time.

7. The method according to claim 6, characterized in that, During vehicle braking, the braking method is selected based on the comparison between the working height before failure and the set height threshold. When the working height before failure is higher than the set height threshold, regenerative braking is used, and the actual braking deceleration generated by regenerative braking is controlled not to exceed the upper limit of braking deceleration. When the working height before failure is lower than or equal to the set height threshold, mechanical braking is applied, and the actual braking deceleration generated by the mechanical braking is controlled not to exceed the upper limit of the braking deceleration. The set height threshold is determined based on the vehicle's stability requirements at its highest operating height.

8. The method according to claim 1, characterized in that, The dynamically calculated security control parameters include: Establish a decreasing relationship between working height and upper limit of safe speed, wherein the upper limit of safe speed decreases as working height increases, and the upper limit of safe speed is not less than a preset minimum safe speed threshold. Establish a decreasing relationship between working height and upper limit of braking deceleration, wherein the upper limit of braking deceleration decreases as working height increases, and the upper limit of braking deceleration is not less than a preset minimum braking deceleration threshold. The minimum safe speed threshold and the minimum braking deceleration threshold are determined based on the vehicle's stability requirements at its highest operating height.

9. The method according to claim 8, characterized in that, The control of the vehicle based on safety control parameters includes: After determining that the height sensor has failed, control the vehicle's operating speed to not exceed the safe speed limit. When braking is required, the actual braking deceleration is controlled to not exceed the upper limit of the braking deceleration.

10. The method according to claim 1, characterized in that, After determining that the height sensor has failed, continuously monitor the rate of change of the height sensor's height. Set a sensor recovery confirmation time threshold. When the height change rate is continuously within the reasonable range within the recovery confirmation time threshold, it is determined that the height sensor has recovered to normal. At this time, stop controlling the vehicle according to the safety control parameters and restore the vehicle to its original operating state.

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