A method for measuring forces on a leg of a crane

Abstract

The present application relates to the technical field of hoisting machinery measurement, and discloses a kind of force measurement methods of crane outrigger, comprising: recording the outrigger pressure data of forward and reverse operating conditions and constructing discretization angle coordinate system, data is matched to standard angle node;At the matching node, average pressure component and signed direction pressure deviation component are calculated;Combining effective bearing area, geometric weight coefficient and equivalent support stiffness, a weighted outrigger deformation coordination reference is established;The deviation component is deducted from real-time acquisition to obtain the compensated force value;Calculate the residual of the compensated force value and the reference, and when determining a single abnormal outrigger, the nominal force estimate value is calculated according to the remaining normal outrigger and the reference. Through the present application, the equivalent pressure deviation caused by mechanical hysteresis is eliminated, the force measurement accuracy is improved, and the measurement data output is maintained when a single outrigger is abnormal, enhancing the fault tolerance of the system.

Description

Technical Field

[0001] This invention relates to the field of crane machinery measurement technology, specifically a method for measuring the force on the outriggers of a crane. Background Technology

[0002] When cranes perform lifting operations, they typically deploy hydraulic outriggers to support the undercarriage and ensure overall stability. Existing outrigger stress measurement methods primarily involve installing pressure sensors in the outrigger hydraulic cylinders to collect hydraulic system pressure data and calculate the outrigger stress by combining this data with the effective bearing area. This measurement data provides fundamental support for the crane control system to assess the crane's center of gravity, calculate anti-tipping moments, and perform safety monitoring.

[0003] In actual operation, when the upper slewing body of the crane performs a slewing motion, the driving torque and inertial torque are transmitted to the lower chassis through the slewing bearing. Due to frictional hysteresis in the mechanical structure, the lower chassis will experience torsional deformation related to the direction of rotation. This structural deformation will exert a lateral force on the hydraulic outriggers and, together with the sealing friction of the hydraulic cylinders, create a direction-dependent equivalent pressure deviation. Most existing measurement methods directly use single-shot acquisition or simple time-series filtering, failing to effectively separate and deduct the equivalent pressure deviation that varies with the direction of rotation. This results in deviations in the force measurement values ​​at the same location when the equipment is dynamically rotating or affected by structural hysteresis, thus limiting the overall accuracy of force measurement.

[0004] On the other hand, the crane's four hydraulic outriggers, together with the undercarriage, constitute a statically indeterminate structure with four-point spatial support. During operation, if a local anomaly occurs in an individual hydraulic outrigger, such as internal leakage in the hydraulic cylinder, the corresponding pressure measurement data will deviate from the actual physical support state. Conventional measurement schemes lack physical constraint analysis methods based on the overall structural deformation coordination relationship of the chassis, and the force monitoring of each outrigger is independent. When the pressure data of a local outrigger is distorted, the existing system cannot accurately locate the specific outrigger with the anomaly, nor can it use the data of the other normal outriggers to back-calculate and evaluate the actual force condition at that location, resulting in insufficient fault tolerance of the entire safety monitoring system when faced with single-point measurement anomalies. Therefore, this invention provides a method for measuring the force on the outriggers of a crane to address the shortcomings of the existing technology. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for measuring the force on the outriggers of a crane. This method solves the problems of existing measurement methods, which suffer from equivalent pressure deviations due to mechanical connections and structural friction hysteresis, resulting in limited force measurement accuracy. Furthermore, when individual outriggers experience hydraulic anomalies, the lack of physical constraint analysis methods based on the overall structural deformation coordination of the chassis makes it difficult to accurately locate abnormal outriggers and estimate their true force, leading to insufficient system fault tolerance.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The first aspect of this invention provides a method for measuring the force on the outriggers of a crane, comprising:

[0008] The real-time rotation angle and pressure data of the four hydraulic outriggers are acquired and written into clockwise or counterclockwise rotation discrete data point sets, respectively. Then, in a discretized angle coordinate system containing standard angle nodes, they are converted into clockwise and counterclockwise pressure sequences.

[0009] Using the standard angle node as an index, when the forward and reverse working conditions match and the rotational motion state meets the preset conditions, the clockwise and counterclockwise pressure sequences are matched to determine the effective matching nodes in the forward and reverse directions.

[0010] At the matching node, the average pressure component is obtained by averaging the corresponding clockwise and counterclockwise pressure values, and the signed half-difference is calculated to extract the signed directional pressure deviation component.

[0011] The average pressure component is converted into average axial force based on the effective pressure-bearing area corresponding to each pressure chamber. The weighted calculation is then performed by combining the geometric weight coefficient and equivalent support stiffness of each outrigger to establish a weighted outrigger deformation coordination benchmark.

[0012] The target standard angle node is determined based on the current real-time rotation angle, and the pressure deviation component and the deformation coordination benchmark corresponding to the node are extracted from the calibration data group that matches the current working condition.

[0013] The extracted pressure deviation component is converted from positive to negative according to the current rotation direction and subtracted from the real-time pressure. The compensation force value of each hydraulic outrigger is calculated in combination with the effective pressure bearing area.

[0014] Calculate the deformation coordination residual between each of the compensated force values ​​and the deformation coordination benchmark. When the absolute value of the residual continuously exceeds a preset threshold, and a candidate abnormal outrigger is uniquely identified, the other three outriggers are in normal condition, and the geometric weight coefficient of the candidate abnormal outrigger is non-zero, the compensated force value and the deformation coordination benchmark of the other hydraulic outriggers (excluding the candidate abnormal outrigger) that are in normal measurement and support conditions are used to back-calculate and output the nominal force estimate and abnormality flag of the candidate abnormal outrigger.

[0015] Furthermore, before the step of recording the real-time slewing angle and the pressure data of the four hydraulic outriggers, the method further includes: acquiring the status of the hoisting mechanism brake and the luffing mechanism brake; when both the hoisting mechanism and the luffing mechanism are in braking state, the absolute value of the real-time slewing angular velocity is greater than the angular velocity dead zone threshold, and the absolute value of the real-time slewing angular acceleration is not greater than the calibrated angular acceleration threshold, it is determined that the current working condition meets the calibration data acquisition conditions; the step of writing the clockwise slewing discrete data point set or the counterclockwise slewing discrete data point set respectively specifically involves: determining the slewing direction based on the positive or negative sign of the real-time slewing angular velocity, and writing the real-time slewing angle and the pressure data with a unified timestamp into the slewing discrete data point set corresponding to the slewing direction.

[0016] Furthermore, the step of converting the clockwise and counterclockwise discrete data point sets into clockwise and counterclockwise pressure sequences specifically includes: reading the timestamps associated with the pressure data and the real-time rotation angle; performing time-series synchronization of the pressure data and the real-time rotation angle based on the timestamps; and performing cycle expansion, unidirectional continuous rotation segment division, abnormal sample removal, and angle sorting on the real-time rotation angle; performing linear interpolation calculations to convert the clockwise and counterclockwise discrete data point sets into clockwise and counterclockwise pressure sequences with the same angle step size, respectively; and converting the corresponding real-time rotation angular velocity and real-time rotation angular acceleration to the same standard angle node to generate clockwise and counterclockwise motion state sequences.

[0017] Furthermore, determining the effective matching nodes in both directions specifically includes: determining whether the same standard angle node simultaneously possesses both the effective clockwise pressure value and the effective counterclockwise pressure value; if both are effective, reading the corresponding clockwise motion state sequence and the corresponding counterclockwise motion state sequence, calculating the amplitude difference between the clockwise rotation angular velocity and the counterclockwise rotation angular velocity, and calculating the angular acceleration difference after unifying the sign according to the rotation direction; when the amplitude difference is not greater than the speed matching threshold, the angular acceleration difference is not greater than the acceleration matching threshold, and the corresponding hoisting state, outrigger deployment state, and ground support working condition are all the same, and the corresponding boom length difference and luffing angle difference are not greater than the corresponding preset allowable deviation thresholds, the standard angle node is determined as the effective matching node in both directions.

[0018] Furthermore, the step of averaging the clockwise and counterclockwise pressure values ​​to obtain the average pressure component specifically refers to adding the clockwise and counterclockwise pressure values ​​at the same standard angle node and then dividing by two to obtain the average pressure component; the step of performing a signed half-difference calculation to extract the signed directional pressure deviation component specifically refers to subtracting the counterclockwise pressure value from the clockwise pressure value at the same standard angle node and then dividing by two to obtain the signed directional pressure deviation component that retains the positive and negative signs.

[0019] Furthermore, the step of establishing a weighted outrigger deformation coordination benchmark by weighting the average axial force using geometric weighting coefficients and equivalent support stiffness specifically includes: obtaining the support point coordinates of four support points relative to the chassis reference coordinate system; determining four geometric weighting coefficients based on the support point coordinates; the four geometric weighting coefficients satisfy the following conditions: the sum of the geometric weighting coefficients is zero, the sum of the products of each geometric weighting coefficient and the corresponding support point's lateral coordinate is zero, and the sum of the products of each geometric weighting coefficient and the corresponding support point's longitudinal coordinate is zero; dividing the average axial force corresponding to each hydraulic outrigger by the corresponding equivalent support stiffness, multiplying by the corresponding geometric weighting coefficient, and then taking the algebraic sum of the four calculation results to obtain the weighted outrigger deformation coordination benchmark corresponding to the matching node.

[0020] Furthermore, the step of subtracting the signed directional pressure deviation component from the real-time pressure specifically includes: acquiring the real-time rotational angular velocity; when the real-time rotational angular velocity is greater than the angular velocity dead zone threshold, the rotational direction state coefficient is set to positive one; when the real-time rotational angular velocity is less than the negative angular velocity dead zone threshold, the rotational direction state coefficient is set to negative one; when the absolute value of the real-time rotational angular velocity is not greater than the angular velocity dead zone threshold, and the duration since entering this state is not greater than the preset direction holding time, the rotational direction state coefficient retains the value before entering this state; when the absolute value of the real-time rotational angular velocity is not greater than the angular velocity dead zone threshold, and the duration since entering this state is greater than the preset direction holding time, the rotational direction state coefficient is set to zero; multiplying the signed directional pressure deviation component corresponding to the target standard angle node by the rotational direction state coefficient, and subtracting the resulting product value from the real-time pressure of the corresponding hydraulic outrigger.

[0021] Furthermore, the calculation of the deformation coordination residual between the compensated force value and the weighted outrigger deformation coordination benchmark specifically includes: dividing the compensated force value of each of the four hydraulic outriggers by their respective equivalent support stiffness to obtain the equivalent support displacement of the corresponding hydraulic outrigger; multiplying the equivalent support displacement of each hydraulic outrigger by the corresponding geometric weight coefficient and performing algebraic summation; and subtracting the weighted outrigger deformation coordination benchmark corresponding to the target standard angle node from the algebraic summation result to obtain the deformation coordination residual.

[0022] Furthermore, the step of uniquely identifying a candidate abnormal outrigger specifically includes identifying a unique suspected internal leakage candidate abnormal outrigger. The identification steps are as follows: determining whether the current working condition enters the pressure holding diagnostic window. The entry conditions include the hoisting mechanism and luffing mechanism being in a braking state, the slewing drive command being zero, the absolute value of the real-time slewing angular velocity being continuously not greater than the angular velocity dead zone threshold, and the hoisting state and the boom length and luffing angle remaining unchanged; within the pressure holding diagnostic window, linear fitting is used to calculate the pressure change rate of each hydraulic outrigger; when the pressure change rate of a single hydraulic outrigger is lower than the negative pressure drop rate threshold, the duration of the state being lower than this value exceeds the preset pressure drop duration, and the absolute values ​​of the pressure change rates of the other three hydraulic outriggers are not greater than the preset normal pressure change rate threshold, the hydraulic outrigger is identified as the candidate abnormal outrigger.

[0023] Furthermore, the step of back-calculating the nominal force estimate based on the compensated force values ​​of the remaining normal outriggers and the weighted outrigger deformation coordination benchmark specifically involves: using the weighted outrigger deformation coordination benchmark corresponding to the target standard angle node as the minuend; using the sum of the products of the ratio of the compensated force value of each normal outrigger to the equivalent support stiffness corresponding to that normal outrigger and the corresponding geometric weight coefficient as the subtrahend, and subtracting the difference; the geometric weight coefficient corresponding to the candidate abnormal outrigger is a non-zero value; multiplying the difference obtained by the subtraction by the equivalent support stiffness of the candidate abnormal outrigger, and dividing by the geometric weight coefficient of the candidate abnormal outrigger, to obtain the nominal force estimate of the candidate abnormal outrigger.

[0024] A second aspect of the present invention provides a crane outrigger force measurement system, comprising a mechanical body, a data acquisition unit, and a main controller;

[0025] The main mechanical body includes an upper rotating body, a lower chassis, and four hydraulic outriggers; the four hydraulic outriggers are respectively set at four support positions on the lower chassis, and together with the lower chassis, form a spatial four-point support statically indeterminate structure.

[0026] The data acquisition unit includes an angle encoder, four pressure sensors, and a brake status acquisition node. The angle encoder is installed on the slewing mechanism and is used to output the slewing angle of the upper slewing body relative to the lower chassis. The four pressure sensors are respectively set in the rodless chambers of the four hydraulic outriggers and are used to acquire the pressure of the corresponding hydraulic cylinders. The brake status acquisition node is used to acquire the status of the hoisting mechanism brake and the luffing mechanism brake.

[0027] The main controller communicates with the data acquisition unit via a communication bus, receives and processes the data output by the data acquisition unit, and executes the crane outrigger force measurement method provided in the first aspect of the present invention.

[0028] Furthermore, the main controller reads the slewing angle, the pressure of each hydraulic cylinder, and the status of the hoisting mechanism brake and the luffing mechanism brake according to a preset sampling period; the main controller receives the boom length, luffing angle, hoisting status, outrigger deployment status, hydraulic oil temperature, outrigger hydraulic lock valve status, and outrigger cylinder stroke status output by the external control system through the communication bus.

[0029] Furthermore, when the hoisting state, boom length, luffing angle, outrigger deployment state, and ground support conditions remain unchanged, and the angular velocity amplitude and angular acceleration of clockwise and counterclockwise rotation are within a preset matching range, the static load component and ground support reaction force component under the same absolute rotation angle are not affected by the rotation direction; the main controller matches the clockwise and counterclockwise pressure data under the same absolute rotation angle, obtains the average pressure component through averaging calculation, and extracts the signed directional pressure deviation component through half-difference calculation, so as to separate the direction-independent pressure component and the directional-related equivalent pressure deviation formed by the torsional deformation of the undercarriage, hydraulic cylinder sealing friction, slewing bearing reaction force, and chassis structural hysteresis.

[0030] Furthermore, the main controller calculates the average axial force of each hydraulic outrigger based on the average pressure component, the effective bearing area of ​​each hydraulic outrigger, spatial position parameters, and a predetermined equivalent support stiffness, and establishes a weighted outrigger deformation coordination benchmark. The main controller calculates the deformation coordination residual between each compensated force value and the deformation coordination benchmark, and determines the abnormal state of the hydraulic outrigger based on the deformation coordination residual, pressure sensor status, communication status, and outrigger pressure changes. When a candidate abnormal outrigger is uniquely identified, the other three outriggers are in normal status, and the geometric weight coefficient of the candidate abnormal outrigger is non-zero, the main controller uses the compensated force value and the deformation coordination benchmark of the remaining hydraulic outriggers (excluding the candidate abnormal outrigger) that are in normal measurement and support states to back-calculate and output the nominal force estimate and abnormality flag of the candidate abnormal outrigger. The nominal force estimate is used for data fault tolerance and fault assessment in the case of single-point measurement abnormalities.

[0031] This invention provides a method for measuring the force on the outriggers of a crane. It has the following beneficial effects:

[0032] 1. This invention establishes a discretized angular coordinate system, aligns and matches pressure data in both clockwise and counterclockwise rotation directions using standard angular nodes, and performs averaging and signed half-difference calculations to separate the directional pressure deviation component. This deviation component is subtracted from the collected pressure data during real-time monitoring, effectively eliminating the equivalent pressure deviation caused by undercarriage torsional deformation, structural friction, and hysteresis that varies with the rotation direction. This improves the accuracy of force measurement on the crane outriggers under both static and dynamic conditions.

[0033] 2. This invention is based on the statically indeterminate structural characteristics of a crane chassis with four-point spatial support. It derives geometric weighting coefficients that satisfy static equilibrium conditions by combining the coordinates of the support points, and introduces equivalent support stiffness parameters to transform the pressure of a single hydraulic outrigger into a parameter reflecting the overall structural displacement. By weighted calculation of the force data of each hydraulic outrigger, a weighted outrigger deformation coordination benchmark is established, providing a constraint model that conforms to objective physical laws for the overall stress and deformation state of the chassis. This provides a reliable data comparison basis for subsequent anomaly monitoring.

[0034] 3. This invention accurately identifies abnormal states of hydraulic outriggers by calculating the residual between the compensated force values ​​of each outrigger and the weighted outrigger deformation coordination benchmark. When measurement data is distorted due to internal leakage or other reasons in individual hydraulic outriggers, the system can reverse-engineer the nominal force estimate of the abnormal outrigger based on the force data of the other three normal outriggers and the existing weighted outrigger deformation coordination benchmark. This mechanism enables the measurement system to output complete four-point force data even when facing local hardware failures, significantly enhancing the system's fault-tolerant operation capability and equipment condition assessment capability. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the outrigger force measurement system of the present invention;

[0036] Figure 2 This is an overall flowchart of the outrigger force measurement method of the present invention;

[0037] Figure 3 This is a schematic diagram of the four-point support structure and coordinate system of the crane chassis of the present invention;

[0038] Figure 4 This is a flowchart of the calibration data acquisition and discrete data point set generation process of the present invention;

[0039] Figure 5 This is a flowchart of the determination of effective matching nodes in both directions and the separation of pressure deviations in this invention.

[0040] Figure 6 This is a flowchart of the weighted outrigger deformation coordination benchmark establishment and residual calculation process of the present invention;

[0041] Figure 7 This is a flowchart of the real-time rotation direction status determination and pressure compensation process of the present invention.

[0042] Figure 8 This is a flowchart of the pressure-holding diagnostic window and candidate abnormal support leg determination of the present invention;

[0043] Figure 9 This is a logic diagram for back-calculating the nominal force estimate of a single abnormal outrigger according to the present invention. Detailed Implementation

[0044] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] See attached document Figure 1 The crane outrigger force measurement system provided in this embodiment includes a mechanical body, a data acquisition unit, and a main controller.

[0046] The main mechanical body includes an upper rotating body, a lower chassis, and four hydraulic outriggers. The four hydraulic outriggers are positioned at four support points on the lower chassis, forming a spatially supported, statically indeterminate structure. The main controller communicates with the data acquisition unit via a controller local area network bus, receiving and processing the data output by the data acquisition unit.

[0047] The data acquisition unit includes an angle encoder, four pressure sensors, and a brake status acquisition node. The angle encoder is installed on the slewing mechanism and is used to output the slewing angle of the upper slewing body relative to the lower chassis; the four pressure sensors are respectively set in the rodless chambers of the four hydraulic outriggers and are used to collect the pressure of the corresponding hydraulic cylinders; the brake status acquisition node collects the opening and closing status of the hoisting mechanism brake and the luffing mechanism brake, respectively.

[0048] During system operation, the main controller reads the slewing angle, the pressure of each hydraulic cylinder, and the status of the hoisting mechanism brake and the luffing mechanism brake according to a preset sampling period. The main controller can also receive data from the existing control system of the crane, such as boom length, luffing angle, load status, outrigger deployment status, hydraulic oil temperature, and outrigger hydraulic lock valve status, via the controller area network bus. If the crane is equipped with outrigger cylinder stroke detection nodes, the main controller also receives the stroke status of each outrigger cylinder.

[0049] When a crane performs a slewing motion, the slewing drive torque generated by the upper slewing body and the inertial torque generated during acceleration or deceleration are transmitted to the lower chassis via the slewing bearing, causing torsional deformation of the lower chassis related to the slewing direction. This torsional deformation can exert a lateral force on the hydraulic outriggers and, together with the hydraulic cylinder sealing friction, the slewing bearing reaction force, and the chassis structural hysteresis, forms a direction-related equivalent pressure deviation.

[0050] When the load condition, boom length, luffing angle, outrigger deployment state, and ground support condition remain unchanged, and the angular velocity amplitude and angular acceleration state of clockwise and counterclockwise rotation are within the preset matching range, the static load component and ground support reaction force component under the same absolute rotation angle are basically unaffected by the rotation direction, while the signs of the direction-related equivalent pressure deviation are approximately opposite in the clockwise and counterclockwise rotation conditions.

[0051] Based on the above differences, the main controller matches the clockwise and counterclockwise pressure data under the same absolute rotation angle, obtains the average pressure component through averaging calculation, and obtains the signed directional pressure deviation component through half-difference calculation, thereby separating the direction-independent pressure component and the direction-dependent pressure deviation component.

[0052] The main controller calculates the average axial force on each hydraulic outrigger based on the average pressure component, the effective bearing area of ​​each hydraulic outrigger, spatial position parameters, and a pre-determined equivalent support stiffness, and establishes a weighted outrigger deformation coordination benchmark. During system operation, the main controller performs weighted calculations on the compensated force values ​​of each hydraulic outrigger to obtain the deformation coordination residual. Based on the deformation coordination residual, as well as the pressure sensor status, communication status, and outrigger pressure changes, the main controller determines whether the measurement data or support status of the hydraulic outriggers is abnormal.

[0053] If only one candidate outrigger is identified, and the measurement and support states of the other three hydraulic outriggers are normal, the main controller calculates the nominal force estimate of the candidate outrigger based on the weighted outrigger deformation coordination benchmark and the compensated force values ​​of the other three hydraulic outriggers, and outputs an anomaly alarm message. The nominal force estimate is used for data fault tolerance and fault assessment in the case of single-point measurement anomalies, and does not indicate that the hydraulic outrigger that has experienced hydraulic leakage or reduced support capacity has recovered its actual support capacity.

[0054] Clockwise and counterclockwise pressure values ​​refer to the clockwise and counterclockwise standard pressure values ​​of the corresponding pressure sequence at the standard angle node; the real-time slewing direction is determined based on the positive and negative signs of the real-time slewing angular velocity; the boom posture includes at least the boom length and luffing angle; the equipment status includes at least one of the following: pressure sensor status, data communication status, cylinder stroke status, and hydraulic outrigger support status; the lifting status includes at least the lifting load weight and the lifting device status; a normal outrigger refers to an outrigger whose corresponding pressure sensor status, data communication status, cylinder stroke status, and hydraulic outrigger support status all have no abnormal alarms and no suspected internal leakage has occurred.

[0055] See attached document Figure 2 The crane outrigger force measurement method in this embodiment includes steps S10 to S50, each step being executed in the order of calibration data acquisition, data synchronization and angle resampling, forward and reverse data matching, pressure component separation and deformation coordination benchmark establishment, online compensation and anomaly handling.

[0056] S10: Obtain the status of the hoisting mechanism brake and the luffing mechanism brake from the brake status acquisition node, and determine whether the current working condition meets the calibration data acquisition conditions.

[0057] When both the hoisting mechanism and the luffing mechanism are in braking mode, the absolute value of the real-time slewing angular velocity is greater than the angular velocity dead zone threshold, and the absolute value of the real-time slewing angular acceleration is not greater than the calibrated angular acceleration threshold, the current working condition is determined to meet the calibration data acquisition conditions. The main controller determines the slewing direction based on the sign of the real-time slewing angular velocity and writes the real-time slewing angle with a unified timestamp and the pressure data of the four hydraulic outriggers into either the clockwise slewing discrete data point set or the counterclockwise slewing discrete data point set, respectively.

[0058] S20: Establish a discretized angle coordinate system in the main controller's storage space. The main controller performs time-series synchronization of rotation angle data and pressure data based on a unified timestamp, and performs cycle expansion, unidirectional continuous rotation segment division, abnormal sample removal, and angle sorting on the rotation angle data.

[0059] After data preprocessing, the main controller performs linear interpolation calculations to convert the clockwise and counterclockwise discrete data point sets into clockwise and counterclockwise pressure sequences with the same angular step size, respectively. The main controller also converts the corresponding rotational angular velocity and rotational angular acceleration to the same standard angle node, forming clockwise and counterclockwise motion state sequences.

[0060] S30 uses standard angle nodes as indexes to perform forward and reverse angle matching on clockwise and counterclockwise pressure sequences.

[0061] When a standard angle node simultaneously possesses valid clockwise and counterclockwise pressure values, and the corresponding difference in angular velocity amplitude and the difference in angular acceleration after unifying the sign according to the direction of rotation are both within a preset matching threshold, the standard angle node is determined as a valid matching node in both directions. Standard angle nodes that do not simultaneously possess valid data in both directions or whose motion state does not meet the matching conditions will not participate in subsequent pressure component calculations.

[0062] S40, at each effective matching node in both directions, the clockwise and counterclockwise pressure values ​​are averaged to obtain the average pressure component reflecting the static load distribution and ground support reaction force; the clockwise and counterclockwise pressure values ​​are calculated with a signed half difference to obtain the signed directional pressure deviation component.

[0063] The main controller converts the average pressure component into the average axial force of each hydraulic outrigger based on the effective bearing area of ​​each hydraulic outrigger. It determines the geometric weighting coefficient based on the spatial coordinates of the four outrigger support points and, in conjunction with the equivalent support stiffness of each hydraulic outrigger, performs a weighted calculation of the average axial force of the four hydraulic outriggers to establish a weighted outrigger deformation coordination benchmark corresponding to each standard angle node.

[0064] S50 writes the signed directional pressure deviation sequence formed by the signed directional pressure deviation components, along with the weighted outrigger deformation coordination benchmark sequence, geometric weight coefficients, and equivalent support stiffness established under the same calibration conditions, into a non-volatile storage unit as a set of calibration data.

[0065] The main controller associates and stores the calibration data set with the outrigger deployment status, boom length, calibration load range, hydraulic oil temperature range, and ground support conditions. After entering the normal operation phase, the main controller matches the current operating conditions with the stored calibration data set; if no calibration data set that meets the applicable conditions is found, directional pressure deviation compensation and nominal force estimation are not performed, and a calibration condition mismatch status is output.

[0066] When a calibration data set that meets the applicable conditions exists, the main controller determines the rotation direction state coefficient based on the real-time rotation angular velocity and queries the signed directional pressure deviation sequence based on the real-time rotation angle. The main controller subtracts the corresponding signed directional pressure deviation component from the real-time pressure of each hydraulic outrigger and calculates the compensated force value of each hydraulic outrigger in conjunction with the effective bearing area of ​​the hydraulic cylinder.

[0067] The main controller substitutes the compensated force values ​​of the four hydraulic outriggers into the weighted outrigger deformation coordination to calculate the deformation coordination residual. When the deformation coordination residual continuously exceeds the deformation coordination residual threshold, and only one candidate abnormal outrigger is identified based on the pressure change trend, sensor status, or communication status, the main controller back-calculates the nominal force estimate of the candidate abnormal outrigger based on the compensated force values ​​of the remaining three normal outriggers and the weighted outrigger deformation coordination benchmark.

[0068] The main controller outputs the original pressure-converted force value, compensated force value, nominal force estimate, and abnormal status flag for candidate abnormal outriggers. When it is confirmed that the hydraulic cylinder has internal leakage, retraction, or reduced support capacity, the nominal force estimate is only used for fault assessment and must not replace the measured data to deactivate overload protection, overturning protection, or outrigger failure protection.

[0069] The following is in conjunction with the appendix Figure 3 To be continued Figure 7 The specific implementation process of steps S10 to S50 will be explained separately.

[0070] See attached document Figure 3 Step S10 is used to determine whether the current working condition meets the conditions for collecting forward and reverse calibration data, and if the conditions are met, records the rotation angle, hydraulic outrigger pressure, and corresponding timestamp. Step S10 includes the following sub-steps.

[0071] S101. When the crane performs hoisting or luffing operations, the load will generate vertical or radial displacement, causing a change in the center of gravity of the entire crane and creating additional loads on each hydraulic outrigger. To reduce the impact of hoisting and luffing operations on the directional pressure deviation calibration results, the main controller only collects calibration data when both the hoisting and luffing mechanisms are in braking mode.

[0072] The main controller reads the hoisting mechanism brake state variables output by the brake state acquisition node. and the state variables of the luffing mechanism brake When the brake is in the closed state, the state variable takes the value of 1; when the brake is in the released state, the state variable takes the value of 0.

[0073] The main controller calculates the real-time rotational velocity based on the rotational angle output by the angle encoder. and real-time rotational acceleration In one implementation, the main controller calculates the rotational angular velocity based on the difference in rotational angle between adjacent sampling times and the corresponding sampling time interval, and then calculates the rotational angular acceleration based on the difference in adjacent rotational angular velocities and the corresponding time interval. Before calculation, the main controller can perform low-pass filtering on the rotational angle or rotational angular velocity to reduce the impact of encoder quantization error and mechanical vibration on the calculation results.

[0074] The main controller establishes calibration data acquisition conditions. Its basic Boolean expression is:

[0075] ;

[0076] in, It is the dead zone threshold for angular velocity, used to eliminate minute speed fluctuations caused by encoder zero-position drift, mechanical vibration, or backlash in the rotary mechanism when stationary. The angular acceleration threshold is used to calibrate and exclude large dynamic loads generated during slewing starts, braking, and rapid gear changes. The dead zone threshold for angular velocity can be determined based on the maximum speed noise of the encoder when the crane is stationary and the preset safety margin. For example, it can be determined through test calibration by collecting encoder speed data for a preset time period, such as 10 minutes, under windless and completely stationary conditions. The maximum absolute value of the data is then superimposed with a preset safety factor to obtain the dead zone threshold. , It can be determined based on the maximum rotational acceleration allowed to participate in forward and reverse calibration.

[0077] For cranes equipped with boom telescopic mechanisms or adjustable outrigger mechanisms, the main controller also collects the boom telescopic mechanism locking status and outrigger mechanism locking status as additional data acquisition conditions. Boom length, luffing angle, lifting status, outrigger deployment status, and hydraulic oil temperature are provided by the crane's existing control system via the controller area network bus; if the existing control system does not provide certain operating parameters, these can be input by calibration personnel into the main controller before calibration begins and stored in conjunction with the calibration data.

[0078] When both the hoisting mechanism and the luffing mechanism are in braking mode, the absolute value of the real-time slewing angular velocity is greater than the angular velocity dead zone threshold, and the absolute value of the real-time slewing angular acceleration is not greater than the calibrated angular acceleration threshold, If the determination is true, the main controller begins to collect calibration data. When the real-time rotational angular velocity is positive, the collected data is written into the clockwise rotational discrete data point set; when the real-time rotational angular velocity is negative, the collected data is written into the counterclockwise rotational discrete data point set.

[0079] S102, when When the condition is true, the main controller allocates storage areas for clockwise and counterclockwise rotation data respectively, and establishes a sliding window data queue within the corresponding storage area. The maximum depth of the sliding window is determined based on the available storage space of the main controller, the sampling period, and the rotation angle range to be covered.

[0080] when When the main controller determines that the crane is in a clockwise rotation state, it writes the rotation angle of the current sampling period, the pressure data of the four hydraulic outriggers, and the sampling timestamp into the clockwise rotation discrete data point set. The discrete data point set rotating clockwise is represented as:

[0081] ;

[0082] In the formula, The sampling sequence number of the clockwise rotation data. This represents the total number of sampling points for clockwise rotation data. For the first The measured clockwise angle for each sampling period For the first Within the sampling period, the first Measured pressure of each hydraulic outrigger Each group and All are clockwise sampling timestamps Associated storage.

[0083] when When the main controller determines that the crane is in a counter-clockwise rotation state, it writes the rotation angle of the current sampling period, the pressure data of the four hydraulic outriggers, and the sampling timestamp into the counter-clockwise rotation discrete data point set. The discrete data point set rotating counterclockwise is represented as:

[0084] ;

[0085] In the formula, The sampling sequence number of the counterclockwise rotation data. This represents the total number of sampling points for the counter-clockwise rotation data. For the first The counterclockwise measured angle for each sampling period For the first Within the sampling period, the first Measured pressure of each hydraulic outrigger. (Each group) and All are sampled counterclockwise timestamps Associated storage.

[0086] The main controller divides the acquired data into multiple unidirectional continuous rotation data segments based on the sign of the rotational angular velocity and the continuous sampling time. When the real-time rotational angular velocity enters the angular velocity dead zone and continues for more than the preset segment time, or when the sign of the real-time rotational angular velocity changes, the main controller terminates the current unidirectional continuous rotation data segment and establishes a new unidirectional continuous rotation data segment when the acquisition conditions are met again. The preset segment time is greater than one sampling period and can be determined based on the allowable short-term speed fluctuation duration of the rotation mechanism.

[0087] When a unidirectional continuous rotation data segment crosses the 0° position, the main controller periodically expands the rotation angle. When the clockwise rotation angle changes from approximately 360° to approximately 0°, 360° is added to the angle after 0°; when the counterclockwise rotation angle changes from approximately 0° to approximately 360°, continuous processing is performed in the opposite direction, ensuring that the rotation angle within the same unidirectional continuous rotation data segment remains monotonically changing.

[0088] S103, the angle encoder, pressure sensor, and brake status acquisition nodes can send data to the main controller according to different communication cycles. Since the sampling time and message transmission time of each node are not completely consistent, the rotation angle and pressure data read by the main controller within the same control cycle may correspond to different actual times. Different rotation speeds will also cause changes in the angle increment between adjacent sampling points, resulting in a non-uniform distribution of clockwise and counterclockwise measured angles within the rotation angle range.

[0089] The main controller synchronizes the rotation angle and pressure data based on the timestamp carried in the message; when the message does not carry a timestamp, the message reception time recorded by the main controller is used as the time reference. For any angle sampling time, the main controller searches for adjacent pressure samples that are on either side of the sampling time in time in the pressure samples of the corresponding hydraulic outrigger, and performs linear time interpolation based on the timestamps of the two pressure samples to obtain the synchronous pressure value corresponding to the sampling time of that angle.

[0090] When a pressure sample is missing on one side at the angle sampling time, but the time difference between the pressure sample on the other side and that angle sampling time is not greater than the maximum synchronization error, the main controller uses that pressure sample as the synchronization pressure value. When no pressure sample meets the maximum synchronization error requirement, the corresponding data record is marked as invalid. The maximum synchronization error can be determined based on the crane's maximum calibrated slewing angular velocity, allowable angular misalignment error, and pressure change rate.

[0091] After timing synchronization is completed, the main controller will use the synchronized rotation angle data and pressure data for subsequent angle domain linear interpolation and forward and reverse angle matching.

[0092] See attached document Figure 4 Step S20 is used to establish a standard angular coordinate sequence and convert the clockwise and counterclockwise rotation data that have completed timing synchronization into a pressure sequence with consistent angular step size. Step S20 includes sub-steps S201 and S202.

[0093] S201, the main controller establishes a discretized angular coordinate system covering the entire slewing angle range of the crane within the storage space. Using the slewing direction directly in front of the crane as the 0° reference, the angular range greater than or equal to 0° and less than 360° is divided into multiple standard angular nodes. 0° and 360° correspond to the same slewing position; only the 0° node is retained in the standard angular coordinate sequence.

[0094] The main controller determines the angle deviation step length based on the angle encoder resolution, sampling period, calibration rotation speed, allowable angle matching error, and available storage capacity. . It can be selected within the range of 0.1° to 1°, and meets the following requirements. The value is an integer. The main controller follows... Establish a standard angular coordinate sequence The formula for calculating the standard angle node is:

[0095] ;

[0096] In the formula, This is the index number of the standard angle node. ; The total number of nodes at the standard angle. A standard angular coordinate sequence is used to determine the angular index used for both clockwise and counterclockwise rotation data.

[0097] Before performing linear interpolation in the angle domain, the main controller processes each unidirectional continuous rotation data segment. For a unidirectional continuous rotation data segment that spans the 0° position and has completed periodic unfolding, the main controller adds or subtracts 360° from the standard angle node based on the continuous angle range of the unidirectional continuous rotation data segment to obtain the equivalent unfolding angle within the unidirectional continuous rotation data segment; after the interpolation result is generated, it is written back to the corresponding standard angle node that is greater than or equal to 0° and less than 360°.

[0098] The main controller sorts the samples in each unidirectional continuous rotation data segment according to the rotation angle and merges duplicate samples whose angle difference is not greater than a preset angle merging threshold. When multiple valid samples correspond to the same angular position, one sample can be selected based on the proximity of the sampling time to the target time, or the pressure value, rotation angular velocity, and rotation angular acceleration can be averaged separately.

[0099] The main controller discards data with discontinuous timestamps, pressure values ​​exceeding the sensor's range, or changes in adjacent samples exceeding a preset abnormal change threshold. When the angle difference between adjacent valid samples exceeds the maximum interpolation angle interval, linear interpolation is not performed between the two samples. The processed unidirectional continuous rotation data segments are monotonically arranged according to the expanded rotation angle.

[0100] S202, the main controller converts the valid samples in each unidirectional continuous rotation data segment into a standard angular coordinate sequence. When the adjacent sampling periods are short and the pressure change between adjacent valid samples can be approximated as a linear change, linear interpolation is used to calculate the pressure value at the standard angular node.

[0101] The main controller processes each standard angle node in the standard angle coordinate sequence sequentially, and rotates the discrete data point set clockwise. and counterclockwise rotating discrete data point set Find adjacent valid samples located on either side of the target angle. Rotate the discrete data point set clockwise. For example, let the target standard angle node be... The measured clockwise angles on both sides of the target angle are respectively and Then the following condition is met:

[0102] ;

[0103] For a unidirectional continuous rotation data segment spanning the 0° position, in the formula... The equivalent unfolding angle determined in step S201 is used. When the target angle is the same as a certain measured angle, the main controller directly uses the pressure value corresponding to that measured angle without interpolation.

[0104] When the target angle exceeds the effective angle range of the current unidirectional continuous rotation data segment, there are no effective samples on both sides of the target angle, or the angle difference between two adjacent samples is greater than the maximum interpolation angle interval, the main controller marks the result corresponding to the target angle as invalid and does not perform data extrapolation outside the angle range.

[0105] After determining the valid samples on both sides of the target angle, the main controller extracts the first... Measured pressure of each hydraulic outrigger at two sample locations. and When the absolute value of the difference between two adjacent measured angles is greater than the minimum angle difference threshold... At that time, the clockwise standard pressure value at the target standard angle node is calculated according to the following formula. :

[0106] ;

[0107] Minimum angle difference threshold Determined based on the angle encoder resolution, this is used to avoid division by zero or numerical amplification when two adjacent angle values ​​are the same or too close. When the angle difference between two samples does not meet the minimum angle difference requirement, the main controller skips the current sample combination and continues to search for the next set of adjacent valid samples that meet the conditions; if no sample combination that meets the conditions can be found, the standard angle node is marked as invalid.

[0108] The main controller processes each standard angle node in the same way to generate a clockwise pressure sequence. When there are multiple interpolation results for clockwise continuous unidirectional rotation data segments at the same standard angle node, if the dispersion between the multiple results does not exceed the preset repeatability error threshold, the average value is taken as the clockwise standard pressure value of that node; if it exceeds the repeatability error threshold, the node is marked as invalid.

[0109] Counterclockwise pressure sequence The same processing method is used to generate the data. The counterclockwise rotation data shows a decreasing rotation angle in the sampling time order, but after completing the angle sorting and equivalent unfolding angle processing, the interpolation result is directly written to the corresponding standard angle node, and the array reversal or mirror flipping is not performed on the counterclockwise pressure sequence.

[0110] The main controller also converts the rotational angular velocity and rotational angular acceleration to the same standard angle node according to the adjacent samples and interpolation coefficients used in the pressure data, generating clockwise motion state sequences and counterclockwise motion state sequences respectively. The pressure sequence and motion state sequence use the same valid node flag for forward and reverse angle matching in step S30.

[0111] See attached document Figure 5 Step S30 is used to filter angle nodes in the standard angle coordinate sequence that are valid for both clockwise and counterclockwise rotation and whose motion states match, and to form pairs of matching data with the same angle in both directions. Step S30 includes sub-steps S301 and S302.

[0112] S301, the main controller establishes valid node flags for both clockwise and counterclockwise pressure sequences. Standard angle node. When the pressure values ​​of all four hydraulic outriggers at a given point are obtained through interpolation from valid samples, the valid flag of the node in the corresponding direction is set to 1; when any hydraulic outrigger lacks a valid pressure value at that point, the valid flag of the node in the corresponding direction is set to 0.

[0113] When the standard angle node When both the clockwise and counterclockwise node valid flags are 1, the main controller reads the corresponding rotational angular velocity and rotational angular acceleration from the clockwise and counterclockwise motion state sequences, and determines whether the forward and reverse motion states match.

[0114] The main controller calculates the magnitude difference between the clockwise and counterclockwise rotational angular velocities. For rotational angular acceleration, the main controller first standardizes its sign according to the direction of rotation: for clockwise rotation, it uses the real-time rotational angular acceleration. When rotating counterclockwise, real-time rotational angular acceleration is used. The opposite of the sign. A positive angular acceleration after sign unification indicates acceleration in the current direction of rotation, while a negative angular acceleration indicates deceleration in the current direction of rotation.

[0115] When the difference in slewing angular velocity amplitude is no greater than the velocity matching threshold, the difference in slewing angular acceleration after sign unification is no greater than the acceleration matching threshold, and the corresponding data on hoisting status, boom length, luffing angle, outrigger deployment status, hydraulic oil temperature range, and ground support conditions are all matched, the main controller determines this standard angle node as a valid matching node in both directions. To reduce the impact of slow changes in operating conditions during calibration, the time interval between clockwise and counterclockwise slewing data acquisition should also not exceed the maximum matching time interval. If any condition is not met, the node is marked as invalid.

[0116] The speed matching threshold is determined based on the calibrated slewing speed and the allowable forward and reverse speed deviation; the acceleration matching threshold is determined based on the calibrated angular acceleration threshold and the allowable dynamic load difference; the maximum matching time interval is determined based on the time required for a single forward and reverse calibration and the allowable range of oil temperature, ground support status, and mechanical condition variations. Furthermore, the preset allowable deviation threshold for boom length is determined based on the mechanical clearance of the boom telescopic mechanism and sensor measurement errors; the preset allowable deviation threshold for luffing angle is determined based on the minute displacement fluctuations of the luffing cylinder and the comprehensive error of the angle sensor. For example, through experimental calibration, with a constant load and no telescopic or luffing commands sent, the measured fluctuation amplitudes of boom length and luffing angle are continuously collected over multiple operating cycles. The maximum fluctuation amplitude, superimposed with a preset safety margin, is then used as the preset allowable deviation thresholds for boom length and luffing angle, respectively.

[0117] When multiple sets of clockwise and counterclockwise data exist at the same standard angle node, the main controller will form candidate data pairs based on the order of acquisition time, and then determine whether each candidate data pair is valid according to the aforementioned conditions.

[0118] When multiple valid candidate data pairs exist for the same standard angle node, the main controller calculates the dispersion of the clockwise and counterclockwise standard pressure values ​​of each hydraulic outrigger between different candidate data pairs. If the dispersion is no greater than the repeatability error threshold, the average value is taken for the clockwise and counterclockwise standard pressure values ​​and their corresponding motion parameters. If the pressure dispersion of any hydraulic outrigger exceeds the repeatability error threshold, the standard angle node is marked as invalid. The repeatability error threshold is determined based on the measurement error of the pressure sensor and the fluctuation range of normal repeatability calibration results.

[0119] Both clockwise and counterclockwise pressure sequences follow standard angle nodes. Storage, therefore the same index number Corresponding to the same absolute rotation angle, the main controller directly reads the forward and reverse data according to the same index number, and does not perform array reversal or mirror flipping on the counterclockwise pressure sequence.

[0120] S302, for the valid matching nodes in both directions determined in step S301 The main controller synchronously reads the clockwise and counterclockwise standard pressure values ​​of the four hydraulic outriggers, forming a pair of forward and reverse angle matching data corresponding to the standard angle node.

[0121] Standard angle nodes that are invalid (clockwise or counterclockwise), have mismatched forward and reverse motion states, have mismatched calibration parameters, or do not meet repeatability requirements will not participate in the calculation of subsequent average pressure components and signed directional pressure deviation components.

[0122] When the load, boom length, luffing angle, and ground support conditions remain constant, the upper slewing body has the same geometric position relative to the lower chassis when it is at the same absolute slewing angle. Therefore, when clockwise and counterclockwise slewing reaches this angle, the direction-independent pressure components experienced by each hydraulic outrigger are essentially the same.

[0123] The directional equivalent pressure deviation, caused by torsional deformation related to the chassis and rotation direction, hydraulic cylinder seal friction, rotation drive reaction force, rotation bearing reaction force, and chassis structural hysteresis, has approximately opposite signs when matched in forward and reverse motion states. The forward and reverse angle matching data generated in step S301 is used for averaging and signed half-difference calculations in step S40 to obtain the average pressure component and the signed directional pressure deviation component.

[0124] See attached document Figure 6 Step S40 is used to calculate the average pressure component and the signed directional pressure deviation component based on the forward and reverse angle matching data, and to establish a weighted outrigger deformation coordination benchmark by combining the support point coordinates and equivalent support stiffness of the hydraulic outrigger. Step S40 includes sub-steps S401 to S404.

[0125] S401, the main controller sequentially reads the valid matching nodes in both forward and reverse directions determined in step S30. Step S30 has already completed the screening of node validity, forward and reverse motion status, calibration operating parameters, and data repeatability, so step S401 will not repeat the same judgment.

[0126] For any valid matching node in both directions The main controller reads the first... The standard clockwise pressure value of each hydraulic outrigger and counterclockwise standard pressure value The average pressure component is obtained by averaging the two pressure values. The calculation formula is:

[0127] ;

[0128] In the formula, The index number of the valid matching node in both directions. Number the hydraulic outriggers. ; For the first One hydraulic outrigger at the node The standard pressure value clockwise at the location; For the first One hydraulic outrigger at the node The standard pressure value at the counterclockwise position.

[0129] When the forward and reverse rotation speeds, rotational accelerations, and other calibration conditions are matched, the signs of the directional equivalent pressure deviation are approximately opposite in the clockwise and counterclockwise conditions. Through averaging calculations, the main components of the directional equivalent pressure deviation cancel each other out, and the resulting average pressure component mainly reflects the static load distribution and ground support reaction force at the current rotation angle.

[0130] S402, the main controller performs a signed half-difference calculation on the clockwise and counterclockwise standard pressure values ​​at the same effective matching node in both directions to obtain the... One hydraulic outrigger at the node Signed directional pressure deviation component at the location The calculation formula is:

[0131] ;

[0132] In the formula, Retain the sign of the clockwise standard pressure value minus the counterclockwise standard pressure value. When the value is positive, it indicates that the standard pressure value under clockwise rotation is higher than the standard pressure value under counterclockwise rotation; when... When the value is negative, it indicates that the standard pressure value under clockwise rotation is lower than the standard pressure value under counterclockwise rotation.

[0133] The signed directional pressure deviation component reflects the directional equivalent pressure deviation formed by the torsional deformation of the undercarriage and the direction of rotation, the hydraulic cylinder seal friction, the rotation drive reaction force, the rotation bearing reaction force, and the chassis structural hysteresis, and is not limited to the single hydraulic cylinder seal friction.

[0134] Step S301 has already performed a repeatability check on multiple sets of forward and reverse data at the same standard angle node. Only data that meets the repeatability requirement proceeds to steps S401 and S402; nodes that do not meet the repeatability requirement remain invalid and do not generate average pressure components or signed directional pressure deviation components.

[0135] The S403 features four hydraulic outriggers that support the undercarriage at four different support points, forming a four-point statically indeterminate structure. The weighted outrigger deformation coordination relationship applies to conditions where all four hydraulic outriggers are effectively grounded, the outriggers remain in their deployed state, the undercarriage is within a small deformation elastic range, and there is no significant uneven ground settlement.

[0136] The main controller pre-stores the coordinates of the support points of the four hydraulic outriggers relative to the chassis reference coordinate system. and the equivalent support stiffness of each hydraulic outrigger The four support points are non-coincident and not located on the same straight line to ensure that the geometric weight coefficients have non-zero solutions. The coordinates of the support points can be obtained from the crane's structural design parameters, or they can be measured and written into the main controller during equipment installation or factory calibration.

[0137] No. Equivalent support stiffness of each hydraulic outrigger This is used to characterize the relationship between the increment of the outrigger's supporting force and the increment of the corresponding vertical displacement at the support point. The equivalent support stiffness includes the mechanical equivalent stiffness formed by the hydraulic cylinder and outrigger structure, as well as the ground equivalent vertical stiffness formed by the supporting ground and the outrigger pad.

[0138] The mechanical equivalent stiffness can be determined during the factory calibration stage. During calibration, the crane is placed on a rigid calibration platform, and the four hydraulic outriggers are effectively grounded in a predetermined deployed state. A known increment of vertical support force is applied to the support point to be tested through a calibration loading device, and the corresponding increment of vertical displacement at the support point is measured. The mechanical equivalent stiffness in this deployed state is determined by the ratio of the increment of support force to the increment of vertical displacement.

[0139] When performing on-site incremental calibration on the actual working ground, a temporary displacement measuring device can be used to measure the displacement increment of the support point under the action of a known vertical support force increment, and the comprehensive equivalent support stiffness, including the effects of mechanical structure and ground deformation, can be directly determined. Temporary displacement measuring devices are used only during installation, maintenance, or on-site calibration and are not intended as fixed data acquisition components for routine crane operations.

[0140] When no on-site incremental calibration is performed, the equivalent vertical stiffness of the ground can be determined based on the correspondence established in the pre-test, according to the ground material, outrigger pad specifications, and the equivalent vertical stiffness range of the ground. Then, the mechanical equivalent stiffness and the equivalent vertical stiffness of the ground are converted into the comprehensive equivalent support stiffness according to the equivalent relationship of series elastic elements. When the equivalent vertical stiffness range of the ground cannot be determined, or when the current support conditions exceed the applicable range of the calibration data, the corresponding weighted outrigger deformation coordination benchmark is not used to back-calculate the nominal force estimate.

[0141] The first The vertical displacement of each support point is denoted as When the chassis can be approximated as a small deformation plane, the vertical displacement of each support point can be represented by the overall vertical displacement of the chassis, the rotational component about the transverse axis, and the rotational component about the longitudinal axis.

[0142] The main controller determines the geometric weighting coefficients based on the coordinates of the four support points. The geometric weighting coefficients satisfy the following constraints: the sum of the four geometric weighting coefficients is zero; the sum of the products of each geometric weighting coefficient and the corresponding support point's lateral coordinate is zero; and the sum of the products of each geometric weighting coefficient and the corresponding support point's longitudinal coordinate is zero. Through these constraints, the overall vertical displacement of the chassis and the rotational components in both directions cancel each other out in the weighted calculation.

[0143] The main controller solves the homogeneous linear equation system consisting of the three constraints mentioned above, obtaining four geometric weight coefficients. Since the non-zero solutions of this equation system can be scaled proportionally, the main controller sets one of the non-zero geometric weight coefficients to a predetermined value, or normalizes each geometric weight coefficient according to a predetermined norm, to determine a unique set of weight coefficients.

[0144] When the force increment on the hydraulic outrigger and the vertical displacement increment at the support point satisfy a linear elastic relationship, the first... Axial force on each outrigger With equivalent support stiffness The ratio corresponds to the equivalent support displacement of the outrigger. After the equivalent support displacements of each outrigger are weighted according to the geometric weighting coefficient, they satisfy an approximately stable deformation compatibility relationship under the condition that the outrigger is deployed and the support stiffness remains stable.

[0145] For a rectangular arrangement of four support points, with legs 1 and 4 on one diagonal and legs 2 and 3 on the other diagonal, the geometric weighting coefficient can be taken as... , The corresponding deformation compatibility relationship is expressed as follows: and Sum minus and The sum of these values ​​is approximately kept near the calibration reference.

[0146] When the equivalent support stiffness of the four hydraulic outriggers is the same, or when they have been equivalently normalized through stiffness coefficients, the deformation compatibility relationship can be further converted into an unweighted algebraic relationship of forces on the diagonal outriggers.

[0147] S404, the main controller extracts the average pressure component of the four hydraulic outriggers at the same effective matching node in both directions, and calculates it based on the effective bearing area of ​​each hydraulic cylinder. , will the The average pressure component of each hydraulic outrigger is converted into average axial force. Effective bearing area These are parameters that are predetermined based on the structural dimensions of the hydraulic cylinder and stored in the main controller.

[0148] The main controller is based on geometric weighting coefficients. and equivalent support stiffness The average axial force of the four hydraulic outriggers is weighted and calculated to obtain the node. Corresponding weighted outrigger deformation coordination benchmark . Characterizes the equivalent foundation deformation and displacement at this node. For four The algebraic sum of .

[0149] for , Rectangular support arrangement, for and The sum, minus and sum.

[0150] In the formula, For nodes Weighted outrigger deformation coordination benchmark at the location; For the first One hydraulic outrigger at the node The average axial force at the location; For the first Geometric weighting coefficients of each leg; For the first The equivalent support stiffness of each outrigger. The main controller will... It is stored in association with the corresponding node validity flag, outrigger deployment status, equivalent support stiffness, and calibration working condition parameters.

[0151] Since the overall vertical displacement of the chassis and the rotational components in both directions cancel each other out in the weighted calculation, the influence of the change in the center of gravity position on the weighted result is weakened. It may also include initial installation deviations of the outriggers, chassis manufacturing deviations, initial deformation of the support points, and reference offsets caused by initial ground settlement, therefore, it will not include... It is limited to a value of zero.

[0152] The weighted outrigger deformation coordination benchmark is only applicable to the outrigger deployment state, support stiffness range, and ground support conditions matched with the calibration time. When any outrigger leaves the ground, the support stiffness changes significantly, the chassis exceeds the small deformation elastic range, or significant non-uniform ground settlement occurs, the main controller stops using the corresponding weighted outrigger deformation coordination benchmark to back-calculate the nominal force estimate of the abnormal outrigger.

[0153] See attached document Figure 7 Step S50 is used to store and call the signed directional pressure deviation component and weighted outrigger deformation coordination benchmark obtained in step S40, perform directional deviation compensation on the hydraulic outrigger pressure, calculate the deformation coordination residual, and back-calculate the nominal force estimate of the outrigger when a candidate abnormal outrigger is uniquely determined. Step S50 includes sub-steps S501 to S505.

[0154] S501, the main controller will assign the signed directional pressure deviation components corresponding to each effective standard angle node. A signed directional pressure deviation sequence is constructed according to the node index order and written to non-volatile memory. The main controller also stores the validity flag of each node to prevent the retrieval of data from invalid nodes during subsequent table lookups.

[0155] The main controller will generate a signed directional pressure deviation sequence and a weighted outrigger deformation coordination reference sequence under the same calibration conditions. Geometric weighting coefficients and equivalent support stiffness Save them as the same calibration data group and assign a calibration number to the calibration data group.

[0156] Each calibration data set is also associated with and stores outrigger deployment status, boom length, luffing angle, calibration load range, hydraulic oil temperature range, and ground support conditions. Outrigger deployment status includes outrigger deployment length and locking status; ground support conditions include outrigger pad specifications, ground material type, and equivalent vertical stiffness range of the ground. Relevant parameters are read from the crane's existing control system; parameters not obtainable from the existing control system are entered by calibration personnel before calibration begins.

[0157] Once the routine operation phase begins, the main controller selects the appropriate calibration data set from the non-volatile memory based on the current outrigger deployment status, boom length, luffing angle, load status, hydraulic oil temperature, and ground support conditions. For parameters represented by intervals, the current parameter value should be within the corresponding calibration interval; for parameters represented by status indicators, the current status should be consistent with the calibration status.

[0158] When no applicable calibration data set exists, the main controller does not perform signed directional pressure deviation component compensation, deformation coordination residual calculation, and nominal force estimation back calculation, and outputs a calibration condition mismatch status.

[0159] When the outrigger deployment status changes, or the boom length, luffing angle, lifting status, or hydraulic oil temperature exceeds the applicable range of the calibration data set, or when the ground support working condition is determined to have changed based on the outrigger stroke signal, vehicle level status, continuous drift of deformation coordination residual, or information input by maintenance personnel, the main controller will stop calling the current calibration data set and output a recalibration prompt.

[0160] S502, the main controller determines the rotation direction state coefficient based on the real-time rotation angular velocity. The segmented values ​​of the rotation direction state coefficient are as follows:

[0161] like ,but ;

[0162] like ,but ;

[0163] like Furthermore, the duration from entering the angular velocity dead zone is no greater than the preset direction holding time. ,but ;

[0164] like And the duration from entering the angular velocity dead zone is greater than ,but ;

[0165] In the formula, The real-time rotational angular velocity for the current control cycle; The dead zone threshold for angular velocity; This is the rotation direction state coefficient from the previous control cycle. When the system starts but has not yet detected a valid rotation direction... The initial value is set to 0.

[0166] Direction holding time It is used to maintain the slewing direction before stopping for a short period of time after the slewing deceleration stops, and to prevent the compensation pressure from changing abruptly when the slewing angular velocity enters the dead zone. The duration of the angular velocity dead zone is determined based on the decay time of the directional pressure deviation during the slewing mechanism stop test and is set to be greater than one control cycle. back, Set to 0, and no longer apply pressure compensation related to the direction of rotation.

[0167] When a crane changes its rotation direction, if the absolute value of the reverse rotation angular velocity is greater than... Then, the main controller updates according to the new rotation direction. .

[0168] S503, the main controller obtains the real-time rotation angle at the current moment. and the Real-time pressure of each hydraulic outrigger The real-time rotation angle is converted into a standard angle node index.

[0169] The main controller first Perform a period conversion to obtain the converted angle. Located within a range greater than or equal to 0° and less than 360°, then based on the distance from the angle to the walking distance. Total number of nodes at standard angles Calculate the index of the matching node The matching node index is determined using the following normalization and modulo algorithm to ensure the integrity and conflict-free nature of the mapping rules:

[0170] ;

[0171] In the formula, This is the rounding function. This is for the modulo operation. Therefore, rotation angles close to 0° and close to 360° are mapped to adjacent standard angle nodes according to a periodic relationship.

[0172] Main controller according to Read the signed directional pressure deviation component of the corresponding hydraulic outrigger When a matching node is valid, the pressure deviation component of that node is directly used; when a matching node is invalid, adjacent valid nodes are searched in both directions within the preset maximum interpolation angle range, and linear interpolation is performed according to the periodic distance of the rotation angle.

[0173] When no valid nodes can be found simultaneously on both sides of the current angle within the maximum interpolation angle range, the main controller does not perform compensation for the signed directional pressure deviation component and outputs an invalid compensation data status. In this status, the original pressure-converted force value can still be output, but this force value will not be used to calculate the deformation coordination residual or perform inverse calculation of the nominal force estimate.

[0174] After obtaining the effective signed directional pressure deviation component, the main controller first calculates the... Compensation pressure of each hydraulic outrigger Then, based on the effective pressure-bearing area of ​​the hydraulic cylinder Calculate the compensation force value The calculation relationship is as follows:

[0175] ;

[0176] ;

[0177] In the formula, For the first Compensation pressure of each hydraulic outrigger; For the first The compensation force value of each hydraulic outrigger; This refers to the effective pressure-bearing area of ​​the corresponding hydraulic cylinder.

[0178] This embodiment applies to single-acting piston hydraulic cylinders, or hydraulic cylinders where the rod chamber is connected to the low-pressure return oil passage and the back pressure in the rod chamber is negligible. When the back pressure in the rod chamber cannot be ignored and the rod chamber pressure can be collected, the axial force of the hydraulic cylinder is determined by subtracting the product of the rod chamber pressure and the effective area of ​​the rodless chamber from the product of the rodless chamber pressure and the effective area of ​​the rod chamber. To unify the calculation model, the above calculations all use the pressure of each pressure chamber and its corresponding effective pressure-bearing area as the unified calculation basis. When back pressure exists, the average pressure component and pressure deviation component are equivalent to the net pressure component converted through the unified model. The units and conversion relationships of the physical quantities such as pressure, area, force, and stiffness involved in the above calculations are uniformly referred to Table 1.

[0179] Table 1: Core Variables and Unit Conversion Table for System Formulas

[0180] Hydraulic cylinder pressure P MPa <![CDATA[1MPa=1N / mm 2 ]]> Effective bearing area A <![CDATA[mm 2 ]]> Calculation based on the inner diameter of the hydraulic cylinder structure Axial force F kN F = (P × A) / 1000 Equivalent support stiffness K kN / mm Combined mechanical and ground deformation Equivalent support displacement Eres,Iref mm Equivalent displacement = F / K

[0181] The hydraulic outrigger is subjected to a supporting force generated by the hydraulic cylinder along its axial direction. When the hydraulic cylinder axis coincides with the vertical direction, this supporting force is equal to the vertical supporting reaction force; when there is a non-negligible angle between the hydraulic cylinder axis and the vertical direction, the vertical supporting reaction force is calculated by converting the axial supporting force and the angle into components.

[0182] S504, when the current operating condition matches the calibration data set, all four hydraulic outriggers receive effective compensation force values, and the weighted outrigger deformation coordination benchmark at the matching node is valid, the main controller calculates the deformation coordination residual at the current moment. , The physical dimension is the equivalent displacement.

[0183] The main controller separately sets the compensation force values ​​for the four hydraulic outriggers. Divide by the corresponding equivalent support stiffness The equivalent support displacement of each leg is obtained, and then multiplied by the corresponding geometric weighting coefficient. Then perform an algebraic summation. This algebraic sum is then compared with the weighted leg deformation compatibility datum at the matching node. The difference is the deformation compatibility residual, and the calculation relationship is as follows:

[0184] ;

[0185] In the formula, The deformation coordination residual at the current moment; This indicates the number of elements involved in the residual calculation. The initial force value of each hydraulic outrigger is numerically equal to the compensation force value calculated earlier. In the aforementioned sub-steps and These represent the clockwise and counterclockwise discrete point set indices, respectively. Represents the standard angle node index. The total number of nodes. and For rotation angles and expansion variables, all variable symbols in the document are defined before use and have a consistent meaning; This serves as the weighted outrigger deformation coordination benchmark at the current matching node.

[0186] If the pressure data, signed directional pressure deviation component data, effective bearing area, or equivalent support stiffness of any hydraulic outrigger are invalid, the main controller will not calculate the deformation coordination residual and will output a state where the residual calculation conditions are not met.

[0187] When the measurement link is normal, all four hydraulic outriggers are effectively grounded, the outrigger deployment state and support stiffness remain stable, and the chassis is within the small deformation elastic range, the deformation coordination residual is mainly composed of pressure measurement error, stiffness parameter error, and normal structural deformation fluctuation.

[0188] Deformation coordination residuals may increase when there is uneven ground settlement, outrigger detachment from the ground, a decrease in the actual supporting force of hydraulic outriggers, malfunction of pressure sensors, or significant changes in equivalent support stiffness. Therefore, deformation coordination residuals are used to determine whether the four-point support state deviates from the calibration state, but cannot be used alone to determine the type of anomaly.

[0189] S505, the main controller pre-sets deformation coordination residual threshold. and residual duration period . The determination is based on the comprehensive measurement error of the pressure sensor and data acquisition link, the equivalent support stiffness error, the residual fluctuation range under normal operating conditions, and the preset safety margin.

[0190] In one calibration method, the main controller collects deformation coordination residuals over multiple operating cycles when the hydraulic system, measurement link, and outrigger support status are all normal. The sum of the maximum absolute value of the normal residual or the upper limit of the normal residual statistics and the safety margin is used as the basis for the calibration. . It is determined based on the control cycle of the main controller and the allowable anomaly confirmation time.

[0191] When absolute value continuous One control cycle greater than If the lifting status, boom posture, outrigger deployment status, and ground support condition remain unchanged during the corresponding judgment period, the main controller determines that the four-point support status is abnormal. Possible causes of the abnormality include pressure sensor malfunction, data acquisition link failure, suspected internal leakage in the hydraulic cylinder, localized outrigger settlement, outrigger detachment from the ground, or changes in equivalent support stiffness. The main controller does not determine the specific cause of the abnormality based solely on the deformation coordination residual.

[0192] When it is necessary to determine whether there is suspected internal leakage in the hydraulic cylinder, the main controller calculates the pressure change rate of each hydraulic outrigger in the pressure holding diagnostic window. Entering the pressure holding diagnostic window requires the following simultaneous conditions: the hoisting mechanism and luffing mechanism are in a braking state; the boom extension mechanism is in a locked state during configuration; the slewing drive command is zero; the real-time slewing angular velocity remains within the angular velocity dead zone during the static confirmation time; and the load status and boom attitude remain unchanged. If the crane can provide the slewing brake status, the slewing brake closure status can also be used as an additional condition.

[0193] The main controller performs low-pass filtering or moving average on the pressure data within the pressure holding diagnostic window, and calculates the pressure change rate using linear fitting within a preset calculation time window. The calculation time window contains at least a preset number of continuous valid pressure samples to reduce the impact of individual noise points on the pressure change rate.

[0194] The main controller sets the pressure drop rate threshold. and duration . Determined based on the maximum allowable natural pressure drop rate and safety margin of a normal hydraulic cylinder under pressure-holding conditions; Determined based on the pressure sampling cycle and the allowable anomaly confirmation time.

[0195] When the pressure change rate of a certain hydraulic outrigger is consistently lower than Duration exceeds If the absolute value of the pressure change rate of the other three hydraulic outriggers is not greater than the preset normal pressure change rate threshold, the main controller identifies that outrigger as a candidate abnormal outrigger with continuously decreasing pressure. The preset normal pressure change rate threshold is determined based on the system's hydraulic oil temperature drift characteristics and the background noise of the measurement link, and is used to define the normal pressure fluctuation boundary of outriggers that have not experienced a fault.

[0196] In case of pressure sensor or data acquisition link malfunction, the main controller determines candidate malfunctioning legs based on pressure sensor self-diagnostic information, output over-range, output freeze, message verification error, message counter malfunction, or communication timeout. If the pressure sensor does not have self-diagnostic capabilities, the main controller makes a judgment based on its output status and communication status.

[0197] When there is only one candidate abnormal outrigger, and the pressure sensor status, communication status, and support status of the other three hydraulic outriggers are all normal, the conditions for back-calculation of the nominal force estimate at a single point are met. If there is more than one candidate abnormal outrigger, the candidate abnormal outrigger cannot be determined, or the data of any normal outrigger is invalid, the nominal force estimate back-calculation is not performed.

[0198] When the crane can provide outrigger cylinder stroke signals, the main controller combines pressure changes and cylinder stroke to determine whether the hydraulic support capacity has decreased. When the outrigger hydraulic lock-up valve is locked, the outrigger pressure continues to decrease within the pressure holding diagnostic window, and the corresponding cylinder retracts, the outrigger is marked as having decreased hydraulic support capacity.

[0199] When the pressure sensor output is abnormal, but the outrigger cylinder stroke remains stable, the outrigger hydraulic lock valve is in normal condition, and there is no corresponding load redistribution change in other outriggers, the abnormality can be prioritized as a measurement link abnormality. If the outrigger cylinder stroke signal cannot be obtained, only a single-point support abnormality or suspected internal leakage status is output, and it is not determined as a verified hydraulic cylinder internal leakage.

[0200] When the conditions for back-calculation of the nominal force estimate at a single point are met, the main controller performs nominal force back-calculation based on the compensated force values ​​of the remaining normal outriggers and the weighted outrigger deformation coordination benchmark. Let the currently uniquely determined candidate abnormal outrigger be the [number missing]. Each leg, while satisfying its corresponding geometric weight coefficient Under these conditions, its nominal force estimate The generalized inverse calculation formula is:

[0201] ;

[0202] Hydraulic outrigger No. 1 Taking the only candidate abnormal outrigger as an example, and hydraulic outriggers No. 2, 3, and 4 all meet the normal conditions, due to the constraint conditions... Established, the main controller back-calculates the nominal force estimate of hydraulic outrigger No. 1 based on the weighted outrigger deformation coordination benchmark. The calculation relationship is as follows:

[0203] ;

[0204] In the formula, It should be a non-zero value. This means that, under the assumption that the measurement link and support status of hydraulic outrigger No. 1 are normal, the nominal force estimate obtained by back-calculating the compensated force values ​​of the other three hydraulic outriggers is not equal to the actual support force after hydraulic outrigger No. 1 experiences internal leakage or retraction. When other outriggers are the only candidate abnormal outriggers, the solution is obtained in the same way.

[0205] The main controller outputs the original pressure-converted force value, compensated force value, nominal force estimate, anomaly type flag, and back-calculated valid status flag for each candidate abnormal outrigger. The back-calculated valid status flag is determined based on the calibration condition matching status, node valid status, the uniqueness of the candidate abnormal outrigger, and the data validity of the other three outriggers.

[0206] When the source of the anomaly is confirmed to be a single point of failure in the pressure sensor or data acquisition link, and the hydraulic support remains in normal condition, the nominal force estimate can be used as temporary fault-tolerant data during degraded operation.

[0207] When it is confirmed that the hydraulic cylinder has retracted, leaked internally, or its support capacity has decreased, the nominal force estimate is only used to represent the reference force under normal support assumptions. It must not overwrite the measured data, nor can it be used to deactivate overload protection, overturning protection, or outrigger failure protection. The main controller issues alarms, operation restriction commands, or safety shutdown commands based on the severity of the anomaly.

[0208] When there are two or more candidate abnormal legs, or when the candidate abnormal legs cannot be uniquely determined, the uniqueness condition of single-point force back-calculation is no longer met. The main controller stops the nominal force estimation back-calculation and outputs the multi-point abnormal or abnormal leg uncertain state.

[0209] In a typical construction site scenario, the four hydraulic outriggers of a 50-ton all-terrain crane are deployed in a rectangular configuration, with the undercarriage providing four-point support on the concrete ground. In this embodiment, the system is configured with a data acquisition sampling frequency of 100Hz and a discretized angular coordinate system angle step size... The lifting load during the calibration phase was set to 10t, and the crane's calibrated angular velocity was maintained at approximately 2 r / min. The overall accuracy of the pressure sensor used was 0.5%FS, and the calculation time window for calculating the pressure change rate was set to 2 seconds. To enhance the reproducibility of this embodiment, the following specific calibration parameters were introduced: the equivalent support stiffness of the four outriggers was set to be approximately the same, i.e. Set geometric weight coefficients , Based on system noise, the normal pressure change rate threshold is set at 0.05 MPa / s, and the deformation coordination residual threshold is set at... The setting is 2.5 mm. Before operation, the crane lifts the counterweight, and the hoisting mechanism and luffing mechanism remain braked. When the main controller detects that the slewing state meets the calibration conditions, it triggers calibration data acquisition. The crane completes a continuous 360-degree slewing in both clockwise and counterclockwise directions, and the data acquisition unit records the pressure of each outrigger and the angle encoder data. The main controller eliminates communication asynchronous errors through timing synchronization processing and divides the entire slewing cycle into standard discrete angle nodes with equal step lengths. The forward and reverse matching module compares the clockwise and counterclockwise motion states at the same absolute slewing angle. After verification, the decoupling analysis module extracts the static load component and separates the directional equivalent pressure deviation. The benchmark construction module combines the geometric weights of each outrigger and the equivalent support stiffness parameters to establish a weighted outrigger deformation coordination benchmark for each angle node.

[0210] During lifting and slewing operations, the dynamic compensation module reads the real-time slewing angle and direction, and uses the pressure deviation component to correct the measured pressure of the four hydraulic outriggers. Simultaneously, the anomaly monitoring module calculates the current deformation coordination residual. If the pressure sensor of outrigger 1 experiences an open circuit, the anomaly monitoring module detects that the residual exceeds a threshold and, based on the communication diagnostic status, identifies outrigger 1 as the fault source. Upon confirming a single-point fault and that the support status is normal, the nominal force estimation module uses the compensated force values ​​of the other three outriggers and the weighted outrigger deformation coordination benchmark to calculate the nominal estimated force of outrigger 1, and outputs sensor fault alarms and fault-tolerant data.

[0211] Comparative experiments were conducted using the aforementioned crane, and test data were recorded. The experiments were performed under fixed luffing angle and fixed load conditions. The first stage was a conventional slewing test, comparing the forward and reverse measurements of the force on each outrigger as a function of the slewing angle with and without directional compensation. The second stage was a single-point fault injection test. When the crane was suspended at a specific slewing angle, the signal from the pressure sensor of outrigger No. 1 was cut off, and the system entered a single-point anomaly diagnosis and nominal force estimation inverse calculation mode. The test system recorded the original pressure-converted force value, the dynamically compensated force value, the deformation coordination residual, and the nominal force estimation value. The relevant error index statistics are shown in Table 2.

[0212] Table 2: Statistical Table of Test System Error Indicators

[0213] Maximum deviation of force at the same angle in both directions (kN) Before compensation 15.4 16.2 14.8 15.9 Maximum deviation of force at the same angle in both directions (kN) After compensation 1.2 1.5 1.1 1.3 Single-point fault reconstruction force error (kN) Outrigger #1 broke wire 1.8 - - - Normal operating residual fluctuation range (mm) Continuous rotation [-2.1,1.9] [-1.8,2.2] [-2.0,1.7] [-1.9,2.1]

[0214] See Table 2 and Figure 8 , Figure 9The dynamic compensation scheme suppresses measurement deviations caused by rotational hysteresis. Uncompensated outrigger forces exhibit hysteresis during clockwise and counterclockwise rotations, resulting in differences in force between the forward and reverse directions at the same angle. Through forward and reverse angle matching and component decoupling, the system eliminates directional pressure deviations, and the corrected outrigger force curves coincide in both rotational directions. This mechanism eliminates interference from chassis torsional deformation and hydraulic cylinder friction, ensuring that the output force data reflects the spatial displacement of the crane's center of gravity, thus improving the evaluation accuracy of the anti-tipping system.

[0215] The weighted outrigger deformation coordination benchmark exhibits stability under different operating conditions. With all four outriggers grounded, when the crane rotates to different angles and the center of gravity of the entire vehicle shifts, the deformation coordination residuals calculated by the system remain within the preset tolerance range. The statically indeterminate structure composed of the four hydraulic outriggers satisfies geometric coordination relationships within a small deformation elastic range. The average axial force benchmark extracted by the main controller during the calibration phase filters out dynamic disturbances and can be used as a reference quantity for system state judgment, providing a physical basis for anomaly monitoring.

[0216] During single-point sensor disconnection fault injection, the system possesses single-point fault tolerance and anomaly isolation capabilities. When the original measurement link is interrupted, the anomaly diagnosis module identifies the fault source through residual changes and reconstructs the force data using the nominal force estimation inverse calculation module. The nominal force estimation obtained through inverse calculation is close to the measured force value under the current attitude. This mechanism provides reference support data when the sensor fails, maintaining degraded operation, while simultaneously outputting a status flag to prevent the estimated data from triggering mechanical instability protection, thus realizing the control logic for measurement fault tolerance and safety monitoring.

[0217] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these specific embodiments are merely illustrative. Those skilled in the art can omit, substitute, and modify the details of the above methods and systems in various ways without departing from the principles and essence of the present invention. For example, combining the above method steps to perform substantially the same function and achieve substantially the same result using substantially the same method falls within the scope of the present invention.

Claims

1. A method for measuring the force on the outriggers of a crane, characterized in that, Includes the following steps: The real-time rotation angle and pressure data of the four hydraulic outriggers are acquired and written into clockwise or counterclockwise rotation discrete data point sets, respectively. Then, in a discretized angle coordinate system containing standard angle nodes, they are converted into clockwise and counterclockwise pressure sequences. Using the standard angle node as an index, when the forward and reverse working conditions match and the rotational motion state meets the preset conditions, the clockwise and counterclockwise pressure sequences are matched to determine the effective matching nodes in the forward and reverse directions. At the matching node, the average pressure component is obtained by averaging the corresponding clockwise and counterclockwise pressure values, and the signed half-difference is calculated to extract the signed directional pressure deviation component. The average pressure component is converted into average axial force based on the effective pressure-bearing area corresponding to each pressure chamber. The weighted calculation is then performed by combining the geometric weight coefficient and equivalent support stiffness of each outrigger to establish a weighted outrigger deformation coordination benchmark. The target standard angle node is determined based on the current real-time rotation angle, and the pressure deviation component and the deformation coordination benchmark corresponding to the node are extracted from the calibration data group that matches the current working condition. The extracted pressure deviation component is converted from positive to negative according to the current rotation direction and subtracted from the real-time pressure. The compensation force value of each hydraulic outrigger is calculated in combination with the effective pressure bearing area. Calculate the deformation coordination residual between each of the compensated force values ​​and the deformation coordination benchmark. When the absolute value of the residual continuously exceeds a preset threshold, and a candidate abnormal outrigger is uniquely identified, the other three outriggers are in normal condition, and the geometric weight coefficient of the candidate abnormal outrigger is non-zero, the compensated force value and the deformation coordination benchmark of the other hydraulic outriggers (excluding the candidate abnormal outrigger) that are in normal measurement and support conditions are used to back-calculate and output the nominal force estimate and abnormality flag of the candidate abnormal outrigger.

2. The method for measuring the force on the outriggers of a crane according to claim 1, characterized in that, Before the step of recording the real-time rotation angle and pressure data of the four hydraulic outriggers, the following steps are also included: Acquire the status of the hoisting mechanism brake and the luffing mechanism brake; when both the hoisting mechanism and the luffing mechanism are in braking state, the absolute value of the real-time slewing angular velocity is greater than the angular velocity dead zone threshold, and the absolute value of the real-time slewing angular acceleration is not greater than the calibrated angular acceleration threshold, it is determined that the current working condition meets the calibration data acquisition conditions. The step of writing the discrete data point set for clockwise rotation or counterclockwise rotation respectively specifically involves: determining the rotation direction based on the positive or negative sign of the real-time rotation angular velocity, and writing the real-time rotation angle and pressure data with a unified timestamp into the corresponding rotation discrete data point set for the rotation direction.

3. The method for measuring the force on the outriggers of a crane according to claim 1, characterized in that, The step of converting the clockwise and counterclockwise discrete data point sets into clockwise and counterclockwise pressure sequences specifically includes: Read the timestamp associated with the pressure data and the real-time rotation angle, synchronize the pressure data and the real-time rotation angle in time according to the timestamp, and perform cycle expansion, unidirectional continuous rotation segment division, abnormal sample removal and angle sorting on the real-time rotation angle. Perform linear interpolation calculations to convert the clockwise and counterclockwise discrete data point sets into clockwise and counterclockwise pressure sequences with the same angular step size, respectively; convert the corresponding real-time rotational angular velocity and real-time rotational angular acceleration to the same standard angle node to generate clockwise and counterclockwise motion state sequences.

4. The method for measuring the force on the outriggers of a crane according to claim 3, characterized in that, The determination of valid matching nodes in both directions specifically includes: Determine whether the same standard angle node simultaneously possesses both a valid clockwise pressure value and a valid counterclockwise pressure value; If both are valid, read the corresponding clockwise motion state sequence and the counterclockwise motion state sequence, calculate the amplitude difference between the clockwise rotation angular velocity and the counterclockwise rotation angular velocity, and calculate the difference in angular acceleration after unifying the sign according to the rotation direction; When the amplitude difference is not greater than the speed matching threshold, the angular acceleration difference is not greater than the acceleration matching threshold, and the corresponding hoisting state, outrigger deployment state, and ground support conditions are all the same, and the corresponding boom length difference and luffing angle difference are not greater than the corresponding preset allowable deviation thresholds, the standard angle node is determined as the positive and negative effective matching node.

5. The method for measuring the force on the outriggers of a crane according to claim 1, characterized in that, The average pressure component is obtained by averaging the clockwise and counterclockwise pressure values. Specifically, the average pressure component is obtained by adding the clockwise and counterclockwise pressure values ​​at the same standard angle node and then dividing by two. The process of performing a signed half-difference calculation to obtain the signed directional pressure deviation component specifically refers to subtracting the counterclockwise pressure value from the clockwise pressure value at the same standard angle node and then dividing by two to obtain the signed directional pressure deviation component that retains the positive and negative signs.

6. The method for measuring the force on the outriggers of a crane according to claim 1, characterized in that, The establishment of a weighted outrigger deformation coordination benchmark by combining geometric weighting coefficients and equivalent support stiffness to weight the average axial force specifically includes: Obtain the coordinates of the four support points relative to the chassis reference coordinate system, and determine the four geometric weight coefficients based on the support point coordinates; the four geometric weight coefficients satisfy the following conditions: the sum of the geometric weight coefficients is zero, the sum of the products of each geometric weight coefficient and the corresponding horizontal coordinate of the support point is zero, and the sum of the products of each geometric weight coefficient and the corresponding vertical coordinate of the support point is zero. Divide the average axial force corresponding to each hydraulic outrigger by the corresponding equivalent support stiffness, multiply by the corresponding geometric weight coefficient, and then sum the algebraic values ​​of the four calculation results to obtain the weighted outrigger deformation coordination benchmark corresponding to the matching node.

7. The method for measuring the force on the outriggers of a crane according to claim 1, characterized in that, The step of subtracting the signed directional pressure deviation component from the real-time pressure specifically includes: The real-time rotational angular velocity is obtained. When the real-time rotational angular velocity is greater than the angular velocity dead zone threshold, the rotation direction state coefficient is positive one; when the real-time rotational angular velocity is less than the negative angular velocity dead zone threshold, the rotation direction state coefficient is negative one; when the absolute value of the real-time rotational angular velocity is not greater than the angular velocity dead zone threshold, and the duration since entering this state is not greater than the preset direction holding time, the rotation direction state coefficient retains the value before entering this state; when the absolute value of the real-time rotational angular velocity is not greater than the angular velocity dead zone threshold, and the duration since entering this state is greater than the preset direction holding time, the rotation direction state coefficient is zero. Multiply the signed directional pressure deviation component corresponding to the target standard angle node by the rotation direction state coefficient, and subtract the resulting product value from the real-time pressure of the corresponding hydraulic outrigger.

8. The method for measuring the force on the outriggers of a crane according to claim 1, characterized in that, The calculation of the deformation coordination residual between the compensated force value and the weighted outrigger deformation coordination benchmark specifically includes: Divide the compensated force value of each of the four hydraulic outriggers by their respective equivalent support stiffness to obtain the equivalent support displacement of the corresponding hydraulic outrigger. The equivalent support displacement of each hydraulic outrigger is multiplied by the corresponding geometric weight coefficient and then algebraically summed. The weighted outrigger deformation coordination benchmark corresponding to the target standard angle node is subtracted from the algebraically summed result to obtain the deformation coordination residual.

9. The method for measuring the force on the outriggers of a crane according to claim 1, characterized in that, The process of uniquely identifying a candidate abnormal outrigger specifically includes identifying a unique suspected candidate abnormal outrigger with internal leakage. The identification steps are as follows: The current working condition is determined to enter the pressure holding diagnostic window. The conditions for entering the window include the hoisting mechanism and luffing mechanism being in a braking state, the slewing drive command being zero, the absolute value of the real-time slewing angular velocity being continuously not greater than the angular velocity dead zone threshold, and the hoisting status and the boom length and luffing angle remaining unchanged. The pressure change rate of each hydraulic outrigger is calculated using linear fitting within the pressure-holding diagnostic window. When the pressure change rate of a single hydraulic outrigger is lower than the negative pressure drop rate threshold, the duration of the state below this value exceeds the preset pressure drop duration, and the absolute values ​​of the pressure change rates of the other three hydraulic outriggers are not greater than the preset normal pressure change rate threshold, the hydraulic outrigger is identified as the candidate abnormal outrigger.

10. The method for measuring the force on the outriggers of a crane according to claim 1, characterized in that, The nominal force estimate is calculated by back-calculating the compensated force value of the remaining normal outriggers and the weighted outrigger deformation coordination benchmark, specifically as follows: The weighted outrigger deformation coordination benchmark corresponding to the target standard angle node is used as the minuend; The difference is calculated by subtracting the product of the ratio of the compensated force value of each normal outrigger to the equivalent support stiffness corresponding to that normal outrigger and the corresponding geometric weight coefficient. The geometric weight coefficient corresponding to the candidate abnormal support leg is a non-zero value; The difference obtained by subtraction is multiplied by the equivalent support stiffness of the candidate abnormal outrigger and divided by the geometric weight coefficient of the candidate abnormal outrigger to obtain the nominal force estimate of the candidate abnormal outrigger.

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