Surface abrasion loss monitoring method and system suitable for large shield tunneling machine cutter

Abstract

The invention relates to the technical field of shield tunneling machine cutter quality monitoring, in particular to a surface abrasion loss monitoring method and system suitable for a large shield tunneling machine cutter. Edge width time sequence data of each circle of rotation of the cutter, cutting gap time sequence data of each monitoring position and position coordinate time sequence data are obtained, wherein the cutting gap time sequence data reflect the thickness change of each position of the cutter; as the cutter is influenced by vibration in the operation process, a vibration displacement index is determined based on a cutting gap value and a blade width difference, and the influence of vibration on longitudinal displacement of the cutter is reflected; cutting gap time sequence data are adjusted and corrected through the vibration displacement index of the blade center shaft, the synchronous change and numerical value characteristics of the vibration displacement index of each monitoring position and the position deviation condition; and finally, monitoring the abrasion loss by using the numerical value difference of the cutter at the same moment in the corrected cutting gap time sequence data of different circles. The vibration interference is considered, and the accuracy and effectiveness of the abrasion loss monitoring result are improved.

Description

Technical Field

[0001] The invention relates to the technical field of shield machine cutter quality monitoring, and in particular to a surface wear monitoring method and system suitable for large shield machine cutters. Background Art

[0002] In the tunneling operation of large shield machines, the cutter is a key component that directly acts on the rock and soil medium, and its performance is directly related to the working efficiency and tunneling quality of the shield machine. Under long-term and high-intensity working conditions, the shield machine cutter will gradually lose its cutting ability due to wear, which will not only reduce the tunneling efficiency, but also may cause damage to the cutter itself and other parts of the shield machine; therefore, it is necessary to monitor the wear of the cutter in real time.

[0003] When monitoring the wear of a tool, the existing technology usually analyzes the change in the distance between the blade of the tool and the sensor to determine whether the blade of the tool is worn or damaged. However, during the tunneling operation of the shield machine, the tool will vibrate when it directly acts on media such as rock and soil, and the vibration will cause the tool to shake and move slightly. Therefore, if the impact of vibration on wear monitoring is ignored, the credibility of the final monitoring result will be greatly reduced. Summary of the invention

[0004] In order to solve the technical problem that in the tunneling operation of the shield machine, when the cutter directly acts on the medium such as rock and soil, the vibration phenomenon will cause the cutter to shake slightly and move. Therefore, if the influence of vibration on the wear monitoring is ignored, the credibility of the final monitoring result will be greatly reduced. The purpose of the present invention is to provide a surface wear monitoring method and system for large shield machine cutters. The technical scheme adopted is as follows:

[0005] A surface wear monitoring method for a large shield machine cutter comprises:

[0006] Obtaining blade width time series data of the tool in each rotation, cutting gap time series data at each monitoring position, and position coordinate time series data, wherein the monitoring position includes the blade center axis position and the edge positions on both sides of the blade;

[0007] At each monitoring position, based on the changes in the cutting gap value and the differences in the blade width value at different times, the vibration displacement index at each monitoring position at each time is determined;

[0008] Based on the numerical characteristics of the vibration displacement index at the blade center axis position at each moment, the synchronous changes and numerical characteristics of the vibration displacement index at all monitoring positions at each moment, and the offset of the position coordinates of the monitoring positions over time, the corrected cutting gap time series data at the blade center axis position in each rotation of the tool is obtained;

[0009] The tool wear is monitored based on the difference between the corrected cutting gap values ​​at the blade center axis position under different rotations of the tool.

[0010] Furthermore, the method for obtaining the vibration displacement index includes:

[0011] In the cutting gap time series data at each monitoring position, the absolute value of the difference between the cutting gap values ​​at each two adjacent moments is used as the first vibration displacement factor at the previous moment in the time series between the two adjacent moments;

[0012] In the blade width time series data, the absolute value of the difference between the blade width values ​​at each two adjacent moments is taken as the second vibration displacement factor at the previous moment in the time series between the two adjacent moments;

[0013] The value obtained by normalizing the product of the first vibration displacement factor at each monitoring position at each moment and the second vibration displacement factor corresponding to each moment is used as the vibration displacement index at each monitoring position at each moment.

[0014] Furthermore, the method for obtaining the modified cutting gap time series data includes:

[0015] Based on the vibration displacement index at the blade center axis position at each moment, all moments are divided into normal vibration moments and abnormal vibration moments;

[0016] The cutting gap value at the center axis position of the blade at each normal vibration moment is used as the corrected cutting gap value;

[0017] At the moment of abnormal vibration, analyzing the synchronous changes between the vibration displacement indicators at all monitoring positions to determine the first offset factor;

[0018] At the moment of abnormal vibration, the position coordinates of all monitoring positions are analyzed for their deviation over time, and a second deviation factor is determined;

[0019] The product of the first offset factor and the second offset factor corresponding to each abnormal vibration moment is negatively correlated and normalized to a value as a vibration change unidirectional indicator of the tool at each abnormal vibration moment;

[0020] When the vibration change same-direction index corresponding to a certain abnormal vibration moment is greater than the preset change same-direction threshold, the cutting gap value at the blade center axis position at the normal vibration moment with the smallest time interval with the abnormal vibration moment is used as the corrected cutting gap value at the blade center axis position at the abnormal vibration moment;

[0021] When the vibration change same-direction index corresponding to a certain abnormal vibration moment is less than or equal to the preset change same-direction threshold, the cutting gap value at the blade center axis position at the abnormal vibration moment is used as the corrected cutting gap value;

[0022] The corrected cutting gap values ​​at the blade center axis position at all normal vibration moments and abnormal vibration moments in each rotation of the tool are arranged in time sequence, so as to obtain the corrected cutting gap time sequence data.

[0023] Furthermore, based on the vibration displacement index at the blade center axis position at each moment, all moments are divided into normal vibration moments and abnormal vibration moments, including:

[0024] When the vibration displacement index at the blade center axis position at a certain moment is less than the preset displacement threshold, this moment is considered to be a normal vibration moment;

[0025] When the vibration displacement index at the blade center axis position at a certain moment is greater than or equal to a preset displacement threshold, the moment is considered to be an abnormal vibration moment.

[0026] Furthermore, the method for obtaining the first offset factor includes:

[0027] At each abnormal vibration moment, the difference between the vibration displacement index at the center axis position of the blade and the vibration displacement index at the edge position on each side of the blade is used as the axis deviation coefficient corresponding to the edge position on each side of the blade;

[0028] The absolute value of the difference between the axis deviation coefficients corresponding to the edge positions on both sides of the blade is used as the first offset factor at each abnormal vibration moment.

[0029] Furthermore, the method for obtaining the second offset factor includes:

[0030] At each monitoring position, the position coordinates at each abnormal vibration moment are taken as the end point, and the position at the moment before each abnormal vibration moment is taken as the starting point, to obtain the offset vector at each monitoring position at each abnormal vibration moment;

[0031] At each abnormal vibration moment, the cosine similarity between the offset vector corresponding to the central axis position of the blade and the offset vector corresponding to the edge position on each side of the blade is used as the offset similarity value corresponding to the edge position on each side of the blade;

[0032] The absolute value of the difference between the corresponding offset similarity values ​​at the edge positions on both sides of the blade edge is used as the second offset factor at each abnormal vibration moment.

[0033] Furthermore, the tool wear monitoring is performed based on the difference between the corrected cutting gap values ​​at the blade center axis position under different rotations of the tool, including:

[0034] In the time series data of the corrected cutting gap at the blade center axis position in two adjacent rotations of the tool, the absolute value of the difference between the corrected cutting gap values ​​at the same moment is taken as the blade thickness change value at each moment;

[0035] Based on the fluctuation of blade thickness change value at all times, the wear degree value of the tool under two adjacent rotations is determined;

[0036] When the wear degree value is greater than or equal to the preset wear threshold, a wear warning is required, and when the wear degree value is less than the preset wear threshold, a wear warning is not required.

[0037] Furthermore, the method for obtaining the wear degree value includes:

[0038] The standard deviation of blade thickness variation at all times is normalized as the discrete parameter;

[0039] When the discrete parameter is greater than or equal to a preset discrete threshold, the value after normalizing the maximum blade thickness change value at all moments is used as the wear degree value of the tool;

[0040] When the discrete parameter is less than a preset discrete threshold, the value obtained by normalizing the average of the blade thickness change values ​​at all times is used as the wear degree value of the tool.

[0041] Furthermore, the preset discrete threshold has a value range of (0.6, 1).

[0042] A surface wear monitoring system for large shield machine cutters comprises a processor and a memory, wherein the memory stores at least one instruction, at least one program, a code set or an instruction set, and when the at least one instruction, at least one program, a code set or an instruction set is loaded and executed by the processor, the steps of a surface wear monitoring method for large shield machine cutters are implemented.

[0043] The present invention has the following beneficial effects:

[0044] First, the blade width time series data of the tool under each rotation, the cutting gap time series data of each monitoring position and the position coordinate time series data are obtained, wherein the cutting gap time series data specifically refers to the distance time series data between each monitoring position and the sensor, which can be used to reflect the thickness change of the tool. In view of the fact that the tool of the shield machine is in a rotating state during operation, and the contact with the rock and soil medium will generate vibration, so at each monitoring position, based on the change of the cutting gap value and the difference of the blade width value, the vibration displacement index is determined to preliminarily reflect the influence of vibration on the longitudinal displacement of the tool. When the tool is not worn, when the tool is affected by vibration, the lateral displacement of the tool will cause the displacement of all monitoring positions to be isotropic. Therefore, based on the numerical characteristics of the vibration displacement index at the blade center axis position, the synchronous changes and numerical characteristics of the vibration displacement index at all monitoring positions, and the position offset of the monitoring position, the cutting gap time series data at the blade center axis position of the tool under each rotation is adjusted and corrected, and the corrected cutting gap time series data is obtained. This correction process further reduces the influence of vibration interference on the subsequent wear monitoring results, and improves the accuracy and availability of the data. When the tool is worn, the corrected cutting gap value at the same time will change under different numbers of revolutions. Therefore, the present invention monitors the wear of the tool based on the difference in the corrected cutting gap value under different revolutions. In summary, the present invention takes into account the interference of the vibration of the tool during the operation of the shield machine on the wear monitoring, which can effectively improve the accuracy of the final wear monitoring result. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 A method flow chart of a surface wear monitoring method for a large shield machine cutter provided by an embodiment of the present invention;

[0047] Figure 2 A schematic diagram of three monitoring positions on a tool provided by an embodiment of the present invention;

[0048] Figure 3 A method flow chart of a method for obtaining timing data of a corrected cutting gap provided by an embodiment of the present invention;

[0049] Figure 4 A flow chart of wear monitoring provided by one embodiment of the present invention;

[0050] Figure 5 A system block diagram of a surface wear monitoring system for a large shield machine cutter provided by an embodiment of the present invention;

[0051] Figure 6 A schematic diagram of the system structure of a surface wear monitoring system for a large shield machine cutter provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the surface wear monitoring method and system for large shield machine cutters proposed in accordance with the present invention, in combination with the accompanying drawings and preferred embodiments, and its specific implementation, structure, features and effects are described as follows. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0053] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0054] The following is a detailed description of a method and system for monitoring surface wear of cutting tools of a large shield machine provided by the present invention in conjunction with the accompanying drawings.

[0055] See also Figure 1 , which shows a method flow chart of a surface wear monitoring method for a large shield machine tool provided by an embodiment of the present invention, the method comprising the following steps:

[0056] Step S1: Obtaining the blade width timing data, cutting gap timing data and position coordinate timing data of the tool in each rotation, wherein the monitoring positions include the blade center axis position and the edge positions on both sides of the blade.

[0057] During the operation of the shield machine, the cutter will come into direct contact with the rock and soil medium, thereby cutting the rock and soil medium. Therefore, the cutter must have sufficient strength and wear resistance to ensure stable cutting performance during long-term, high-intensity tunneling. With the development of sensor technology, various high-precision sensors are widely used in the monitoring process of cutter wear, and can capture the operation data of the cutter to reflect the wear condition of the cutter surface.

[0058] Specifically, a laser radar sensor can be embedded in each slot where the tool is installed on the shield machine cutterhead, and the monitoring range should ensure that the width of the tool can be covered. It can obtain the distance parameters between the tool and the laser radar sensor during rotation and the position coordinate data of each position when the tool passes through the sensor coverage range during rotation; the laser wavelength of the laser radar sensor can be set to 1550nm, and the sampling time interval can be set to 1s. At this time, at each moment, the laser radar sensor can obtain the position coordinate data of multiple positions on the width of the tool within the monitoring range and the distance parameters between the tool and the laser radar sensor.

[0059] In view of the fact that the tool will be affected by vibration during contact with the rock and soil medium when working, which may cause slight shaking or displacement of the tool, in the embodiment of the present invention, it is necessary to correct the data changes caused by the vibration phenomenon, so the focus is mainly on the data changes at the center axis position of the blade and the data changes at the edge positions on both sides of the blade, so the center axis position of the blade and the edge positions on both sides of the blade are used as monitoring positions, wherein the center axis position of the blade is the most prominent compared to the entire blade of the tool, so the distance between it and the laser radar sensor will be the shortest, so among the distance parameters of multiple positions acquired by the laser radar sensor at each moment, the minimum value is used as the cutting gap value at the center axis position of the blade, and the position coordinates at the center axis position of the blade can be obtained at the same time; the edge positions on both sides of the blade should be the positions corresponding to the maximum distance parameters on each side of the minimum distance parameter, thereby obtaining the cutting gap value and position coordinates at the edge positions on both sides of the blade, and taking the Euclidean distance between the position coordinates at the edge positions on both sides of the blade as the blade width, so that the blade width timing data of the tool under each rotation, the cutting gap timing data at each monitoring position and the position coordinate timing data can be obtained. Please refer to Figure 2 , which shows a schematic diagram of three monitoring positions on the tool.

[0060] It should be noted that the sampling time interval of the lidar sensor can be adjusted according to the specific implementation scenario, but it should be much shorter than the time it takes for the tool to rotate one circle, to ensure that time series data of sufficient length can be obtained with each rotation of the tool.

[0061] Step S2: At each monitoring position, based on the change of the cutting gap value and the difference of the blade width value at different moments, the vibration displacement index at each monitoring position at each moment is determined.

[0062] Considering that the wear analysis mainly focuses on the blade center axis position, when the cutting gap value at the blade center axis position changes significantly, it means that the blade wear is more obvious. However, in the process of tool wear monitoring, the tool and the cutter disc are both in a rotating state, and the tool will vibrate when it collides with the rock wall in the soil layer during excavation. Then the data monitored by the laser radar sensor may be biased, which will affect the subsequent monitoring accuracy of the tool surface wear; vibration will cause the tool to have lateral and longitudinal displacement, and the longitudinal displacement can be characterized based on the change in the distance between the tool and the laser radar sensor and the change in the blade width value at each monitoring position. Therefore, in order to obtain the actual monitoring data of the tool surface during the excavation process, in the embodiment of the present invention, at each monitoring position, firstly based on the change in the cutting gap value at different times and the difference in the blade width value, the vibration displacement index at each monitoring position at each time is determined to preliminarily reflect the influence of vibration on the longitudinal displacement of the tool.

[0063] Preferably, in one embodiment of the present invention, the method for obtaining the vibration displacement index includes:

[0064] Vibration will cause the distance between the tool and the lidar sensor to change at different times, and this change can be reflected by the changes in the cutting gap value and the blade width value. Therefore, in the cutting gap time series data at each monitoring position, the absolute value of the difference between the cutting gap values ​​at each adjacent moment is taken as the first vibration displacement factor of the previous moment in the time series between the two adjacent moments. The larger the first vibration displacement factor, the more obvious the longitudinal displacement of the tool between the two moments.

[0065] Similarly, in the blade width timing data, the absolute value of the difference between the blade width values ​​at each two adjacent moments is taken as the second vibration displacement factor at the previous moment in the timing sequence between the two adjacent moments. Under normal circumstances, the blade width value of the tool itself should be uniform in one circle, so when the second vibration displacement factor is larger, it can be regarded as being affected by the vibration, and a more obvious longitudinal displacement has occurred, resulting in changes in the blade width value at different moments.

[0066] It should be noted that, in the embodiment of the present invention, the first vibration displacement factor at the last moment in the time sequence is set to be the same as the first vibration displacement factor at the adjacent previous moment; the same applies to the second vibration displacement factor.

[0067] Based on the above analysis, it can be known that both the first vibration displacement factor and the second vibration displacement factor are positively correlated with the longitudinal displacement of the tool caused by vibration, so the product of the first vibration displacement factor at each monitoring position at each moment and the second vibration displacement factor corresponding to each moment is normalized to the value as the vibration displacement index at each monitoring position at each moment. At this time, the larger the vibration displacement index is, the more obvious longitudinal displacement of the tool has occurred at the monitoring position at this moment. Normalization is a technical means well known to those skilled in the art, and the selection of the normalization function can be linear normalization or standard normalization, etc. The specific normalization method is not limited here.

[0068] Step S3: Based on the numerical characteristics of the vibration displacement index at the center axis position of the blade at each moment, the synchronous changes and numerical characteristics of the vibration displacement index at all monitoring positions at each moment, and the offset of the position coordinates of the monitoring positions over time, the corrected cutting gap timing data at the center axis position of the blade in each rotation of the tool is obtained.

[0069] Based on the above steps, the vibration displacement indexes of the three monitoring positions at each moment in the embodiment of the present invention can be obtained to reflect the influence of vibration on the longitudinal displacement of the tool. Then in this step, the influence of vibration on the lateral displacement of the tool is further analyzed, that is, the left and right offsets that the tool may produce. When the tool produces left and right offsets, it is an overall offset. Therefore, the offset of the position coordinates of the monitoring position over time can be used as an indicator for analyzing the influence of lateral displacement, and the vibration displacement index at each monitoring position should also have a synchronous change. Therefore, in this embodiment of the present invention, first, based on the numerical characteristics of the vibration displacement index at the blade center axis position at each moment, the moments can be distinguished, and then according to the synchronous changes and numerical characteristics of the vibration displacement indicators at all monitoring positions, as well as the offset of the position of the monitoring position over time, the cutting gap timing data at the blade center axis position of the tool is corrected to obtain the corrected cutting gap timing data, thereby more accurately reflecting the wear state of the blade part of the tool and providing data support for subsequent wear monitoring.

[0070] Preferably, in one embodiment of the present invention, the method for obtaining the corrected cutting gap timing data includes:

[0071] See also Figure 3 , which shows a method flow chart of a method for obtaining the timing data of the corrected cutting gap in one embodiment of the present invention, the method comprising the following steps:

[0072] Step S301: Based on the vibration displacement index at the blade center axis position at each moment, all moments are divided into normal vibration moments and abnormal vibration moments.

[0073] Based on the analysis in step S2, it can be seen that the larger the vibration displacement index is, the more obvious the longitudinal displacement of the tool has occurred under the influence of vibration. Therefore, when the vibration displacement index at the center axis position of the blade is less than the preset displacement threshold at a certain moment, this moment is considered to be a normal vibration moment, that is, the influence of vibration is small and can be regarded as within the normal range.

[0074] On the contrary, when the vibration displacement index at the center axis position of the blade at a certain moment is greater than or equal to the preset displacement threshold, this moment is considered to be an abnormal vibration moment, that is, it is greatly affected by the vibration, which will have a greater impact on the subsequent wear monitoring and needs to be corrected.

[0075] It should be noted that the preset displacement threshold is 0.45, and the specific value can be adjusted according to the implementation scenario and is not limited here.

[0076] Step S302: taking the cutting gap value at the blade center axis position at each normal vibration moment as the corrected cutting gap value.

[0077] Under normal vibration moments, the vibration of the tool is within the expected range and is considered not to have a significant impact on subsequent wear monitoring. Therefore, in an embodiment of the present invention, the cutting gap value at the center axis position of the blade under each normal vibration moment is directly used as the corrected cutting gap value.

[0078] Step S303: at the moment of abnormal vibration, analyzing the synchronous changes between the vibration displacement indicators at all monitoring positions to determine the first offset factor.

[0079] When the tool deviates to the left or right, the tool will have an overall deviation. If the blade is relatively intact and the wear is weak, the lines will be relatively neat. The vibration displacement index at the center axis monitoring position and the vibration displacement index at the edge position on each side of the blade should change synchronously, that is, the degree of vibration influence should be relatively consistent.

[0080] Therefore, at each moment of abnormal vibration, the difference between the vibration displacement index at the center axis position of the blade and the vibration displacement index at the edge position on each side of the blade is taken as the axis deviation coefficient corresponding to the edge position on each side of the blade. The axis deviation coefficient reflects the consistency between the degree of vibration influence at the edge position on each side of the blade and the degree of vibration influence at the center axis position of the blade, and the smaller the value, the more consistent it is.

[0081] Finally, the absolute value of the difference in the axis deviation coefficients corresponding to the edge positions on both sides of the blade is taken as the first offset factor at each abnormal vibration moment. The larger the first offset factor, the greater the difference in the degree of synchronous change in the degree of vibration influence at the edge positions on both sides of the blade and the center axis position of the blade. The greater the deviation and the smaller the degree of change in the same direction, the higher the possibility of wear on the blade of the tool at the moment of abnormal vibration.

[0082] Step S304: at the moment of abnormal vibration, analyzing the displacement of the position coordinates of all monitoring positions over time, and determining a second displacement factor.

[0083] First, at each monitoring position, the position coordinates at each abnormal vibration moment are taken as the end point, and the position at the moment before each abnormal vibration moment is taken as the starting point, to obtain the offset vector at each monitoring position at each abnormal vibration moment. The offset vector reflects the moving direction and distance of each monitoring position of the tool at each abnormal vibration moment.

[0084] Then, at each moment of abnormal vibration, the cosine similarity between the offset vector corresponding to the center axis position of the blade and the offset vector corresponding to the edge position on each side of the blade is used as the offset similarity value corresponding to the edge position on each side of the blade. The larger the offset similarity value, the higher the degree of consistency between the lateral displacement offset of the center axis of the blade and the lateral displacement offset at the edge position on each side of the blade.

[0085] Finally, the absolute value of the difference between the corresponding offset similarity values ​​at the edge positions on both sides of the blade edge is taken as the second offset factor at each abnormal vibration moment. The larger the second offset factor is, the greater the difference between the offset consistency between the edge positions on both sides of the blade and the center axis position of the blade under the influence of vibration. The smaller the degree of change in the same direction, the higher the possibility of wear on the blade part of the tool at the abnormal vibration moment.

[0086] Step S305: The first offset factor and the second offset factor corresponding to each abnormal vibration moment are integrated to determine the vibration change same direction index of the tool at each abnormal vibration moment.

[0087] Based on the above steps, the first offset factor and the second offset factor at the blade center axis position at each abnormal vibration moment can be obtained, which can be used to measure the same-direction change of the lateral displacement of the monitoring position of the tool under the influence of vibration, and the first offset factor and the second offset factor are both negatively correlated with the degree of the same-direction change. Therefore, the product of the first offset factor and the second offset factor corresponding to each abnormal vibration moment is negatively correlated and normalized to achieve logical relationship correction, thereby obtaining the same-direction index of the vibration change of the tool at each abnormal vibration moment. At this time, the larger the same-direction index of the vibration change, the smaller the wear of the tool at the abnormal vibration moment, and the data offset generated by the tool is caused by vibration, not by the defect or wear of the tool. The negative correlation mapping and normalization here can be performed using the formula exp(-x), where exp() represents an exponential function with the natural constant e as the base, and x represents the independent variable.

[0088] Step S306: Correct the cutting gap value at the blade center axis position at the abnormal vibration moment based on the vibration change same direction index corresponding to the abnormal vibration moment, so as to obtain the corrected cutting gap time series data at the blade center axis position.

[0089] Based on the above analysis, it can be known that the larger the vibration change same-direction index corresponding to a certain abnormal vibration moment is, the more it indicates that the data offset of the tool at the abnormal vibration moment is caused by vibration. Therefore, when the vibration change same-direction index corresponding to a certain abnormal vibration moment is greater than the preset change same-direction threshold, the cutting gap value at the center axis position of the blade at the normal vibration moment with the smallest time interval with the abnormal vibration moment will be used as the corrected cutting gap value at the center axis position of the blade at the abnormal vibration moment.

[0090] On the contrary, the smaller the vibration change same-direction index corresponding to a certain abnormal vibration moment is, the more it indicates that the data offset of the tool at the abnormal vibration moment may be caused by real tool damage or wear. Therefore, when the vibration change same-direction index corresponding to a certain abnormal vibration moment is less than or equal to the preset change same-direction threshold, the cutting gap value at the center axis position of the blade at the abnormal vibration moment is used as the corrected cutting gap value to retain the real tool wear or tool damage data.

[0091] Finally, the corrected cutting gap values ​​at the blade center axis position at all normal vibration moments and abnormal vibration moments in each rotation of the tool are arranged in time sequence to obtain the corrected cutting gap time series data.

[0092] It should be noted that the preset change in the same direction threshold is 0.7, and the specific value can be adjusted according to the implementation scenario and is not limited here.

[0093] At this point, the cutting gap value at the monitoring position of the blade center axis when the tool rotates can be corrected for vibration effects, and corrected cutting gap timing data can be obtained that can truly represent the distance between the blade center axis position and the laser sensor at each moment.

[0094] Step S4: Based on the difference between the corrected cutting gap values ​​at the blade center axis position under different rotations of the tool, the tool wear is monitored.

[0095] Based on the above steps, the real data of the tool surface after correction can be obtained. During use, the tool will collide and grind media such as rock and soil, causing the cutting edge of the tool surface to gradually wear or even become damaged. In an embodiment of the present invention, after obtaining the corrected cutting gap timing data of the tool under each rotation, given that in the corrected cutting gap timing data under different numbers of rotations, the same moment (specifically referring to the moment with the same sequence number in the timing, such as the first moment in the timing data of the first circle and the first moment in the timing data of the second circle are the same moment) corresponds to the point or position on the tool. Therefore, by comparing the difference between the corrected cutting gap values ​​at the position of the blade center axis under different rotations of the tool, the wear state of the tool blade can be analyzed, thereby monitoring the wear of the tool.

[0096] Preferably, in one embodiment of the present invention, based on the difference between the corrected cutting gap values ​​at the blade center axis position under different rotations of the tool, the tool wear is monitored, including:

[0097] See also Figure 4 , which shows a flowchart of wear monitoring in one embodiment of the present invention, specifically comprising the following steps:

[0098] Step S401: Analyze the difference between the corrected cutting gap values ​​when the blade center axis position is at the same time in two adjacent rotations of the tool to obtain the blade thickness change value at each moment.

[0099] In the corrected cutting gap timing data at the blade center axis position under two adjacent rotations of the tool, the absolute value of the difference in the corrected cutting gap values ​​at the same moment is taken as the blade thickness change value at each moment. The larger the blade thickness change value, the more serious the wear of the tool at the corresponding point or position at that moment under two adjacent rotations.

[0100] Step S402: Based on the fluctuation of the blade thickness change value at all times, determine the wear degree value of the tool in two adjacent rotations.

[0101] The normalized value of the standard deviation of the blade thickness change values ​​at all times is used as the discrete parameter. The larger the discrete parameter, the more obvious the discreteness of the blade thickness change values ​​at different times, that is, the greater the fluctuation of the blade thickness, which means that different degrees of wear have occurred in multiple places.

[0102] When the discrete parameter is greater than or equal to the preset discrete threshold, the normalized value of the maximum blade thickness change value at all times is used as the tool wear value; and when the discrete parameter is less than the preset discrete threshold, it means that the blade thickness change value is relatively stable, then the normalized value of the mean of the blade thickness change value at all times is used as the tool wear value. Normalization is a technical means well known to those skilled in the art, and the normalization function can be linear normalization or standard normalization, etc. The specific normalization method is not limited here.

[0103] It should be noted that the preset discrete threshold is set to 0.65, and the specific value can be adjusted according to the implementation scenario and is not limited here.

[0104] Step S403: Monitor the wear of the tool based on the wear degree values ​​of the tool in two adjacent rotations.

[0105] Based on the above analysis, we can get the wear degree value of the tool under two adjacent rotations. Therefore, when the wear degree value is greater than or equal to the preset wear threshold, it is considered that the wear condition is relatively serious and a wear warning is required to remind the construction personnel to repair or replace the tool in time. When the wear degree value is less than the preset wear threshold, no wear warning is required.

[0106] It should be noted that the preset wear threshold in the embodiment of the present invention has a value range of (0.6, 1), which is set to 0.7 here. The specific value can be adjusted according to the implementation scenario and is not limited here.

[0107] In summary, firstly, the blade width time series data of the tool under each rotation, the cutting gap time series data of each monitoring position and the position coordinate time series data are obtained, wherein the cutting gap time series data specifically refers to the distance time series data between each monitoring position and the sensor, which can be used to reflect the thickness change of the tool. In view of the fact that the tool of the shield machine will be in a rotating state during operation, and will vibrate when in contact with the rock and soil medium, the vibration displacement index is determined at each monitoring position based on the change of the cutting gap value and the difference of the blade width value, which is used to preliminarily reflect the influence of vibration on the longitudinal displacement of the tool. When the tool is not worn, when the tool is affected by vibration, the lateral displacement of the tool will cause the displacement of all monitoring positions to be isotropic, so in the present invention, based on the numerical characteristics of the vibration displacement index at the blade center axis position, the synchronous changes and numerical characteristics of the vibration displacement index at all monitoring positions, and the position offset of the monitoring position, the cutting gap time series data at the blade center axis position of the tool under each rotation is adjusted and corrected, and the corrected cutting gap time series data is obtained. This correction process further reduces the influence of vibration interference on the subsequent wear monitoring results, and improves the accuracy and availability of the data. When the tool is worn, the corrected cutting gap value at the same time will change under different numbers of revolutions. Therefore, the embodiment of the present invention monitors the wear of the tool based on the difference in the corrected cutting gap value under different revolutions. The embodiment of the present invention takes into account the interference of the vibration of the tool during the operation of the shield machine on the wear monitoring, which can effectively improve the accuracy of the final wear monitoring result.

[0108] See also Figure 5 , which shows a system block diagram of a surface wear monitoring system for a large shield machine tool provided in one embodiment of the present invention, including a data acquisition module 501, used to implement step S1 in the above method embodiment; a vibration analysis module 502, used to implement step S2 in the above method embodiment; a data correction module 503, used to implement step S3 in the above method embodiment; and a wear monitoring module 504, used to implement step S4 in the above method embodiment.

[0109] It should be noted that the system provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device is divided into different functional modules to complete all or part of the functions described above. In addition, the surface wear monitoring system for large shield machine tools provided in the above embodiment and the surface wear monitoring method for large shield machine tools are of the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0110] See also Figure 6 , which shows a system structure diagram of a surface wear monitoring system for large shield machine tools provided by an embodiment of the present invention, including a processor 600, a memory 601, a bus 602 and a communication interface 603, wherein the processor 600, the communication interface 603 and the memory 601 are connected via the bus 602; wherein the memory 601 may include a high-speed random access memory, the bus 602 may be an ISA bus, a PCI bus or an EISA bus, etc., and the processor 600 may be an integrated circuit chip with signal processing capabilities; the memory 601 stores at least one instruction, at least one program, a code set or an instruction set, and when the at least one instruction, at least one program, a code set or an instruction set is loaded and executed by the processor, a step in a surface wear monitoring method for large shield machine tools is implemented.

[0111] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0112] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A surface wear monitoring method for large shield machine cutters, characterized in that: The method comprises: Obtaining blade width time series data of the tool in each rotation, cutting gap time series data at each monitoring position, and position coordinate time series data, wherein the monitoring position includes the blade center axis position and the edge positions on both sides of the blade; At each monitoring position, based on the changes in the cutting gap value and the differences in the blade width value at different times, the vibration displacement index at each monitoring position at each time is determined; Based on the numerical characteristics of the vibration displacement index at the blade center axis position at each moment, the synchronous changes and numerical characteristics of the vibration displacement index at all monitoring positions at each moment, and the offset of the position coordinates of the monitoring positions over time, the corrected cutting gap time series data at the blade center axis position in each rotation of the tool is obtained; The tool wear is monitored based on the difference between the corrected cutting gap values ​​at the blade center axis position under different rotations of the tool.

2. A surface wear monitoring method for large shield machine cutters according to claim 1, characterized in that: The method for obtaining the vibration displacement index includes: In the cutting gap time series data at each monitoring position, the absolute value of the difference between the cutting gap values ​​at each two adjacent moments is used as the first vibration displacement factor at the previous moment in the time series between the two adjacent moments; In the blade width time series data, the absolute value of the difference between the blade width values ​​at each two adjacent moments is taken as the second vibration displacement factor at the previous moment in the time series between the two adjacent moments; The value obtained by normalizing the product of the first vibration displacement factor at each monitoring position at each moment and the second vibration displacement factor corresponding to each moment is used as the vibration displacement index at each monitoring position at each moment.

3. The surface wear monitoring method for large shield machine cutters according to claim 1 is characterized in that: The method for obtaining the modified cutting gap timing data includes: Based on the vibration displacement index at the blade center axis position at each moment, all moments are divided into normal vibration moments and abnormal vibration moments; The cutting gap value at the center axis position of the blade at each normal vibration moment is used as the corrected cutting gap value; At the moment of abnormal vibration, analyzing the synchronous changes between the vibration displacement indicators at all monitoring positions to determine the first offset factor; At the moment of abnormal vibration, the position coordinates of all monitoring positions are analyzed for their deviation over time, and a second deviation factor is determined; The product of the first offset factor and the second offset factor corresponding to each abnormal vibration moment is negatively correlated and normalized to a value as a vibration change unidirectional indicator of the tool at each abnormal vibration moment; When the vibration change same-direction index corresponding to a certain abnormal vibration moment is greater than the preset change same-direction threshold, the cutting gap value at the blade center axis position at the normal vibration moment with the smallest time interval with the abnormal vibration moment is used as the corrected cutting gap value at the blade center axis position at the abnormal vibration moment; When the vibration change same-direction index corresponding to a certain abnormal vibration moment is less than or equal to the preset change same-direction threshold, the cutting gap value at the blade center axis position at the abnormal vibration moment is used as the corrected cutting gap value; The corrected cutting gap values ​​at the blade center axis position at all normal vibration moments and abnormal vibration moments in each rotation of the tool are arranged in time sequence, so as to obtain the corrected cutting gap time sequence data.

4. A surface wear monitoring method for large shield machine cutters according to claim 3, characterized in that: Based on the vibration displacement index at the blade center axis position at each moment, all moments are divided into normal vibration moments and abnormal vibration moments, including: When the vibration displacement index at the blade center axis position at a certain moment is less than the preset displacement threshold, this moment is considered to be a normal vibration moment; When the vibration displacement index at the blade center axis position at a certain moment is greater than or equal to a preset displacement threshold, the moment is considered to be an abnormal vibration moment.

5. The surface wear monitoring method for large shield machine cutters according to claim 3 is characterized in that: The method for obtaining the first offset factor includes: At each abnormal vibration moment, the difference between the vibration displacement index at the center axis position of the blade and the vibration displacement index at the edge position on each side of the blade is used as the axis deviation coefficient corresponding to the edge position on each side of the blade; The absolute value of the difference between the axis deviation coefficients corresponding to the edge positions on both sides of the blade is used as the first offset factor at each abnormal vibration moment.

6. The surface wear monitoring method for large shield machine cutters according to claim 3 is characterized in that: The method for obtaining the second offset factor includes: At each monitoring position, the position coordinates at each abnormal vibration moment are taken as the end point, and the position at the moment before each abnormal vibration moment is taken as the starting point, to obtain the offset vector at each monitoring position at each abnormal vibration moment; At each abnormal vibration moment, the cosine similarity between the offset vector corresponding to the central axis position of the blade and the offset vector corresponding to the edge position on each side of the blade is used as the offset similarity value corresponding to the edge position on each side of the blade; The absolute value of the difference between the corresponding offset similarity values ​​at the edge positions on both sides of the blade edge is used as the second offset factor at each abnormal vibration moment.

7. The surface wear monitoring method for large shield machine cutters according to claim 1 is characterized in that: The tool wear monitoring is performed based on the difference between the corrected cutting gap values ​​at the blade center axis position under different rotations of the tool, including: In the time series data of the corrected cutting gap at the blade center axis position in two adjacent rotations of the tool, the absolute value of the difference between the corrected cutting gap values ​​at the same moment is taken as the blade thickness change value at each moment; Based on the fluctuation of blade thickness change value at all times, the wear degree value of the tool under two adjacent rotations is determined; When the wear degree value is greater than or equal to the preset wear threshold, a wear warning is required, and when the wear degree value is less than the preset wear threshold, a wear warning is not required.

8. The surface wear monitoring method for large shield machine cutters according to claim 7 is characterized in that: The method for obtaining the wear degree value includes: The standard deviation of blade thickness variation at all times is normalized as the discrete parameter; When the discrete parameter is greater than or equal to a preset discrete threshold, the value after normalizing the maximum blade thickness change value at all moments is used as the wear degree value of the tool; When the discrete parameter is less than a preset discrete threshold, the value obtained by normalizing the average of the blade thickness change values ​​at all times is used as the wear degree value of the tool.

9. A surface wear monitoring method for large shield machine cutters according to claim 8, characterized in that: The value range of the preset discrete threshold is (0.6, 1).

10. A surface wear monitoring system for large shield machine cutters, characterized in that: It includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set or instruction set, and when the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor, the steps of a surface wear monitoring method suitable for a large shield machine tool as described in any one of claims 1 to 9 are implemented.

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