Double-shield guiding system and method

Abstract

The invention provides a double-shield guiding system and method, a supporting shield measuring assembly comprises a total station installed on a duct piece and a laser target arranged on a supporting shield, and the total station obtains coordinates of the laser target; the anterior shield measuring assembly comprises a monocular camera installed on the supporting shield, a feature point set arranged on the anterior shield and a first clinometer, the monocular camera shoots the feature point set in real time, and the first clinometer obtains the inclination angle of the anterior shield; and the upper computer obtains the collected data of the total station, the monocular camera and the first clinometer to obtain the actual postures of the supporting shield and the anterior shield for guiding. According to the guiding system, at least one feature point can be arranged on the anterior shield, the front and rear center coordinates of the anterior shield are obtained through coordinate changes of the feature points captured by the monocular camera in combination with the attitude angle obtained by the first clinometer, the guiding system is simple in hardware, and the needed installation space is small; the guiding method can quickly calculate the deviation between the front and rear center coordinates and the coordinate point on the plan line, and realizes accurate guiding.

Description

Technical Field

[0001] The present application relates to the technical field of shield construction, and in particular to a double shield guiding system and method. Background Art

[0002] The double shield hard rock tunnel boring machine has the characteristics of high construction efficiency for formations with complex rock properties, high rock strength and small turning radius. The cylinder between the support shield and the front shield of the double shield hard rock tunnel boring machine is a spherical cylinder mechanism. The degree of freedom formed by this structure is large. If the stroke of the cylinder is used to calculate the posture of the front shield, it will lead to a large error in the posture of the front shield.

[0003] In related scenarios, for example, a photosensitive target is installed on the front shield, and the laser is emitted through the support shield laser emitter. The photosensitive target collects the offset of the laser, thereby calculating the deviation value of the front shield. However, the width of the photosensitive target is limited. Increasing the width of the photosensitive target leads to an increase in the required installation space, and the system applicability is low. Another example is a method of solving the posture of the front shield by identifying the three-dimensional coordinates of multiple feature points in front based on a monocular or binocular camera. However, the spatial distance between the multiple feature points in front needs to be large enough for the accuracy to meet the requirements.

[0004] Although the above technical solutions all have the function of measuring the front shield posture, they all have the problems of large installation space and high hardware cost. Summary of the invention

[0005] Purpose of the invention: In order to overcome the problems existing in the prior art, the present application provides a dual shield guiding system and method, which ensures the accuracy of the dual shield posture guiding while reducing the installation space.

[0006] Technical solution: The present invention provides a dual shield guiding system, comprising: A support shield measurement assembly, the support shield measurement assembly includes a total station installed on the segment and a laser target set on the support shield, the total station acquires the coordinates of the laser target; A front shield measurement component, the front shield measurement component includes a monocular camera installed on the support shield, a feature point group set on the front shield, and a first inclinometer, the monocular camera shoots the feature point group in real time, and the first inclinometer obtains the inclination angle of the front shield; The host computer obtains the data collected by the total station, the monocular camera, and the first inclinometer, obtains the actual postures of the support shield and the front shield, and performs guidance.

[0007] Furthermore, the host computer obtains the actual posture of the support shield according to the laser target coordinates collected by the total station; On the other hand, the azimuth of the front shield is obtained according to the coordinate changes of the feature point group captured by the monocular camera, and the pitch angle and roll angle of the front shield are obtained by the first inclinometer to obtain the actual posture of the front shield.

[0008] Furthermore, a rear-view prism for rear-view orientation is provided at the rear of the total station.

[0009] Furthermore, at least two spare prisms are provided on the support shield, and the spare prisms are not colinear or coplanar with the laser target.

[0010] Furthermore, the feature point group includes at least one feature point.

[0011] Furthermore, when the number of the feature points is one, the feature points are set on the axis of the monocular camera; when the number of the feature points is greater than one, the feature points are arranged on the center point and the vertex of the cube.

[0012] Furthermore, the front shield measurement component also includes a dual-axis acceleration sensor arranged on the front shield, and the host computer filters the feature point group deviation data recognized by the monocular camera according to the data collected by the dual-axis acceleration sensor.

[0013] A guiding method for a double shield guiding system comprises the following steps: The host computer obtains the coordinates of the laser target collected by the total station and calculates the actual posture of the support shield; The host computer obtains the coordinate change of the feature point group captured by the monocular camera, obtains the angle change of the front shield relative to the supporting shield, and obtains the azimuth angle of the front shield according to the angle change and the azimuth angle of the supporting shield; obtains the pitch angle and roll angle of the front shield according to the first inclinometer, and the host computer calculates the actual posture of the front shield; The host computer guides the front shield according to the deviation between the actual posture of the support shield and the front shield and the planned line.

[0014] Furthermore, the host computer determines whether the dual-axis acceleration sensor data has vibration periodicity, and filters the displacement data accordingly; The data of the dual-axis acceleration sensor has no periodicity, so the median filter method is used to filter the data; The data of the dual-axis acceleration sensor changes periodically, and a low-pass filter is used to filter the data.

[0015] Furthermore, the host computer guides the front shield according to the deviation between the actual posture of the support shield and the front shield and the planned line, which specifically includes the following steps: 1) Obtain all the mileages on the planned line and the three-dimensional coordinate points corresponding to each mileage; 2) According to the distance between the shield machine coordinate point and all the coordinate points on the plan line, select the two plan line coordinate points closest to the shield machine coordinate point from all the distance values, and determine the previous coordinate point and the next coordinate point of the plan line corresponding to the two points according to the mileage elements of the plan line; 3) Calculate the azimuth γ and pitch angle β of the next coordinate point on the plan line relative to the previous coordinate point on the plan line according to the tunneling direction of the shield machine, and set the roll angle α to 0°; 4) Calculate the rotation matrix of the coordinate system with the previous coordinate point of the plan line as the reference point. The calculation method is as follows:

[0016] 5) Calculate the relative position of the shield machine coordinate point in the coordinate system with the previous coordinate point of the planned line as the reference point. The calculation method is as follows:

[0017] Among them, (X 盾构机 , Y 盾构机 , Z 盾构机 ) is the shield machine coordinate, ( X 计划线前一坐标点 , Y 计划线前一坐标点 , Z 计划线前一坐标点 ) are the coordinates of the point in front of the shield machine on the planned line; X is the distance between the coordinate point of the shield machine and the previous coordinate point of the plan line. It is used to determine whether the mileage element in the plan line is excavation from a small mileage to a large mileage. If so, the mileage of the coordinate point of the shield machine is the mileage of the previous coordinate point of the plan line plus X. Otherwise, the mileage of the coordinate point of the shield machine is the mileage of the previous coordinate point of the plan line minus X. Y is the horizontal deviation between the coordinate point of the shield machine and the plan line, and Z is the vertical deviation between the coordinate point of the shield machine and the plan line.

[0018] Beneficial effects: The guidance system of the present invention can set at least one feature point on the front shield, and the front and rear center coordinates of the front shield can be obtained by the coordinate change of the feature point captured by the monocular camera and combined with the posture angle obtained by the first inclinometer. The hardware of the guidance system is simple and the required installation space is small. At the same time, according to the vibration data measured by the acceleration sensor, the situation of large vibration is smoothed, thereby improving the data accuracy of the feature point coordinate change. In addition, the guidance method of the present invention can quickly calculate the deviation of the front and rear center coordinates and the coordinate points on the planned line through the actual posture of the front shield and the support shield, thereby realizing precise guidance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic structural diagram of a double shield guide system according to an exemplary embodiment.

[0021] Figure 2 The figure shows the positional relationship between the coordinate points of the plan line and the coordinate points of the shield machine according to an exemplary embodiment. DETAILED DESCRIPTION

[0022] The following is a further detailed description of the implementation of the present application in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but cannot be used to limit the scope of the present application.

[0023] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0024] A dual shield guidance system, such as Figure 1 As shown, including: A support shield measurement assembly, which includes a total station installed on the segment and a laser target set on the support shield, and the total station obtains the coordinates of the laser target; A front shield measurement component, which includes a monocular camera mounted on the support shield, a feature point group set on the front shield, and a first inclinometer. The monocular camera shoots the feature point group in real time, and the first inclinometer obtains the inclination angle of the front shield. The host computer obtains the data measured by the support shield measurement component and the front shield measurement component and converts them into posture data. It can also communicate with other hardware, read relevant data and control the operation of system-related equipment; it is also used to display, calculate and save data related to the initial calibration and calculation of the system.

[0025] Specifically, the total station in the support shield measurement assembly is installed on the assembled segment, and the laser target is installed on the support shield. The total station emits a laser to the laser target and then reflects it, measures and obtains the coordinates of the laser target, and uploads it to the host computer to derive the actual posture of the support shield. The posture of the support shield mentioned here generally includes the front and rear center coordinates of the support shield, the horizontal and vertical deviations of the front and rear of the support shield, the pitch angle, the roll angle, the azimuth angle, etc. The calculation of the posture is a conventional method in this field, so the calculation principle of the host computer will not be repeated. The posture data obtained by the host computer can be used for real-time display during the shield process, which is convenient for operators to observe in real time.

[0026] In addition, a second inclinometer can be set inside the laser target. The second inclinometer can measure the pitch angle of the support shield and upload it to the host computer for further verification of the calculated pitch angle information.

[0027] In order to better cooperate with the emission of the total station laser, the position where the laser target is installed on the support shield is preferably on the upper part of the support shield and facing the total station; here, the upper part can be understood as the shield segment close to the top of the excavation and away from the shield segment at the bottom of the excavation. The prism on the target needs to be within the visible range of the total station.

[0028] In order to orient the total station, a rear-view prism is set behind the total station. The rear here is set based on the tunneling direction of the shield machine as the front. That is to say, the laser target, total station, and rear-view prism are set in sequence from front to back in the shield direction. The total station first automatically turns to face the rear, measures the coordinates of the rear-view prism for station orientation, and then turns to the front to measure the coordinates of the laser target. The rear-view prism plays the role of rear-view orientation.

[0029] In order to further verify the posture data of the support shield or as a backup measurement method when a problem occurs with the laser target, at least two backup prisms are provided on the support shield, and the two backup prisms are not colinear or coplanar with one of the prisms on the laser target, and the actual posture of the support shield can be calculated by the three-prism method.

[0030] Specifically, the working principle of the front shield measurement component is explained. The monocular camera is set on the support shield to shoot the front shield image, and the feature point group and the first inclinometer are set on the front shield. The monocular camera measures the real-time coordinate changes of the feature point group. The host computer calculates the angle change of the front shield relative to the support shield in combination with the stroke of the main push cylinder of the shield machine, and obtains the azimuth of the front shield based on the angle change and the azimuth of the support shield; then the pitch angle and roll angle of the front shield measured by the first inclinometer are transmitted to the host computer, and the host computer calculates the front and rear center coordinates of the front shield in combination with the data of the main push cylinder stroke and the shield size. So far, the above data can calculate the front and rear center coordinates and attitude angle data of the front shield.

[0031] Here, the setting of the feature point group can be at least one feature point. In the case where the number of feature points is only one, the position of the feature point is preferably located in the axial direction of the monocular camera to ensure that even if the feature point deviates, it can be captured by the monocular camera and will not go out of the field of view. In the case where the number of feature points is multiple, the distribution of the feature points can be that vertex feature points are arranged on each vertex of a cube, and a central feature point is set at the center of the cube. The central feature point serves as the main recognition point of the monocular camera. When the central feature point deviates and cannot be captured by the camera screen, it can be replaced by any vertex feature point located at the vertex of the cube for recognition. Of course, the coordinate changes of multiple feature points can also be simultaneously identified to determine the azimuth of the front shield relative to the support shield, so that more accurate posture data can be obtained.

[0032] Since the front shield vibrates during the excavation process, the coordinates of the feature points collected by the monocular camera are generally fluctuating. The host computer can determine whether there is vibration periodicity by the change of the coordinates. A dual-axis acceleration sensor is set on the front shield. The host computer determines whether the vibration amplitude is periodic based on the data collected by the dual-axis acceleration sensor. Based on the above judgment results, the coordinate values ​​of the feature point group are filtered.

[0033] In order to determine whether the vibration amplitude is periodic, a dual-axis acceleration sensor is set on the front shield, and the measured dual-axis acceleration is transmitted to the host computer. The sampling frequency of the dual-axis acceleration sensor of the host computer must be consistent with the sampling frequency of the monocular camera. The vibration amplitude of the displacement resolved by the monocular camera is calculated and filtered.

[0034] Specifically, the host computer decomposes the data of the dual-axis acceleration sensor, uses the periodic spectrum analysis method in the classical spectrum estimation method to determine whether the data is periodic, and determines the periodicity based on the Fourier transform principle and the autocorrelation coefficient. Specifically, the time series data is expanded into a linear combination of trigonometric functions, and the Fourier coefficients are calculated. The data of the time series is first calculated based on the Fourier coefficients; then the autocorrelation coefficient is used to make a judgment to determine whether it is a periodic function.

[0035] Specifically, the filtering method of displacement data is divided into the following two cases: ① The acceleration sensor data changes without periodicity, and the median filter method is used to filter the data; ② The acceleration sensor data changes periodically, and low-pass filtering is used to process the data.

[0036] The guiding method of the double shield guiding system comprises the following steps: S1. In the initial state, the support shield measurement assembly and the front shield measurement assembly are calibrated.

[0037] The calibration of the support shield measurement assembly refers to the positional relationship between the laser target and the spare prism on the support shield and the support shield coordinate system; The calibration of the front shield measurement component refers to calibrating the deviation of the feature points in the feature point group on the front shield relative to the axis of the monocular camera.

[0038] S2. The host computer obtains the actual posture of the support shield through the data collected by the support shield measurement component, and combines the data collected by the front shield measurement component to obtain the relative angle change of the front shield relative to the support shield, and finally obtains the actual posture of the front shield.

[0039] Specifically, the target coordinates of the laser target on the support shield are measured by a total station installed on the shield segment to obtain the actual posture of the support shield; the pixel coordinates of the feature point group installed on the front shield are measured by a monocular camera installed on the support shield, and the angle change of the front shield relative to the support shield is calculated according to the change, and the azimuth of the front shield is obtained according to the angle change and the azimuth of the support shield; the pitch angle and roll angle of the front shield measured by the first inclinometer are transmitted to the host computer, and the host computer calculates the front and rear center coordinates of the front shield.

[0040] During the excavation process, since the monocular camera is installed on the support shield, the coordinates of the feature points captured by the monocular camera are based on the support shield posture. Therefore, the actual front shield posture needs to be calculated based on the actual posture of the support shield and the conversion relationship between the two.

[0041] The angle change of the front shield relative to the support shield is calculated based on the displacement of the feature point coordinates relative to the monocular camera axis. Initially, the offset of the feature point relative to the monocular camera axis needs to be calibrated, and the deviation between the initial position of the feature point and the monocular camera axis is recorded as (∆x0, ∆y0); if the shield machine advances forward, the monocular camera recognizes that the deviation between the feature point position and the monocular camera axis is (∆xi, ∆yi), then the offset of the feature point coordinates is (∆xi -∆x0, ∆yi -∆y0), and then combined with the main push cylinder stroke data, the azimuth of the front shield is calculated.

[0042] S3. The upper computer makes adjustments based on the deviation between the actual front shield posture and the planned line, which can guide the excavation process and thus achieve precise control of the shield machine posture deviation.

[0043] Specifically, the deviation between the actual front shield posture and the planned line can be calculated according to the following method: like Figure 2 As shown in the figure, the arrow direction is the tunneling direction of the shield machine. The normal tunnel construction plan line includes N mileages, each mileage corresponds to a three-dimensional coordinate point, and each mileage is generally spaced at 0.5m, 1m or 1.5m. The three-dimensional coordinates corresponding to each mileage are input into the guidance system. According to the tunneling direction of the shield machine, the mileage elements in the plan line can be from large mileage to small mileage or from small mileage to large mileage.

[0044] Specifically, the previous coordinate point of the planned line and the next coordinate point of the planned line are determined by the mileage relative to the shield machine coordinate point on the planned line. It should be noted that the shield machine coordinate point mentioned here includes the front and rear center coordinate points of the support shield and the front and rear center coordinate points of the front shield obtained by the above calculation, a total of four. The coordinate point deviation calculation involved below is a separate calculation of the deviation between each coordinate point and the planned line, that is, the deviation of each coordinate point is calculated once, and a total of four deviations are calculated.

[0045] The previous coordinate point of the plan line is the coordinate of the previous mileage point on the mileage plan line of the shield machine coordinate point in the excavation direction. The next coordinate point of the plan line is the coordinate of the next mileage point on the mileage plan line of the shield machine coordinate point in the excavation direction. The interval between the two is 1m. The deviation between the shield machine coordinate point and the plan line can be calculated by the following steps: 1) According to the distance formula between two three-dimensional coordinates, calculate the distance between the shield machine coordinate point and all coordinate points on the plan line, select the two plan line coordinate points closest to the shield machine coordinate point from all distance values, and determine the previous coordinate point and the next coordinate point of the plan line corresponding to the two points according to the mileage elements of the plan line; 2) Calculate the azimuth γ and pitch angle β of the next coordinate point on the plan line relative to the previous coordinate point on the plan line according to the tunneling direction of the shield machine, and set the roll angle α to 0°; 3) Calculate the rotation matrix of the coordinate system with the previous coordinate point of the plan line as the reference point. The calculation method is as follows:

[0046] 4) Calculate the relative position of the shield machine coordinate point in the coordinate system with the previous coordinate point of the planned line as the reference point. The calculation method is as follows:

[0047] Among them, (X 盾构机 , Y 盾构机 , Z 盾构机 ) is the shield machine coordinate, ( X 计划线前一坐标点 , Y 计划线前一坐标点 , Z 计划线前一坐标点 ) are the coordinates of the point in front of the shield machine on the planned line; X is the distance between the coordinate point of the shield machine and the previous coordinate point of the plan line. It is used to determine whether the mileage element in the plan line is excavation from a small mileage to a large mileage. If so, the mileage of the coordinate point of the shield machine is the mileage of the previous coordinate point of the plan line plus X. Otherwise, the mileage of the coordinate point of the shield machine is the mileage of the previous coordinate point of the plan line minus X. Y is the horizontal deviation between the coordinate point of the shield machine and the plan line, and Z is the vertical deviation between the coordinate point of the shield machine and the plan line.

[0048] Finally, it should be noted that the above implementation modes are only used to illustrate the present application, rather than to limit the present application. Although the present application is described in detail with reference to the embodiments, a person skilled in the art should understand that various combinations, modifications or equivalent substitutions of the technical solutions of the present application do not depart from the spirit and scope of the technical solutions of the present application, and should be included in the scope of the claims of the present application.

Claims

1. A double shield guiding system, characterized in that: include: A support shield measurement assembly, the support shield measurement assembly includes a total station installed on the segment and a laser target set on the support shield, the total station acquires the coordinates of the laser target; A front shield measurement component, the front shield measurement component includes a monocular camera installed on the support shield, a feature point group set on the front shield, and a first inclinometer, the monocular camera shoots the feature point group in real time, and the first inclinometer obtains the inclination angle of the front shield; The host computer obtains the data collected by the total station, the monocular camera, and the first inclinometer, obtains the actual postures of the support shield and the front shield, and performs guidance.

2. The double shield guide system according to claim 1, characterized in that: On the one hand, the host computer obtains the actual posture of the support shield according to the laser target coordinates collected by the total station; On the other hand, the azimuth of the front shield is obtained according to the coordinate changes of the feature point group captured by the monocular camera, and the pitch angle and roll angle of the front shield are obtained by the first inclinometer to obtain the actual posture of the front shield.

3. The double shield guide system according to claim 1, characterized in that: A rear-view prism for rear-view orientation is arranged at the rear of the total station.

4. The double shield guide system according to claim 1, characterized in that: The support shield is also provided with at least two spare prisms, and the spare prisms are not colinear or coplanar with the laser target.

5. The double shield guide system according to claim 1, characterized in that: The feature point group includes at least one feature point.

6. The double shield guide system according to claim 5, characterized in that: When the number of the feature points is one, the feature points are set on the axis of the monocular camera; when the number of the feature points is greater than one, the feature points are arranged on the center point and the vertex of the cube.

7. The double shield guide system according to claim 1, characterized in that: The front shield measurement component also includes a dual-axis acceleration sensor arranged on the front shield, and the host computer filters the feature point group deviation data recognized by the monocular camera according to the data collected by the dual-axis acceleration sensor.

8. The guiding method of the double shield guiding system according to claim 1, characterized in that: The following steps are involved: The host computer obtains the coordinates of the laser target collected by the total station and calculates the actual posture of the support shield; The host computer obtains the coordinate change of the feature point group captured by the monocular camera, obtains the angle change of the front shield relative to the supporting shield, and obtains the azimuth angle of the front shield according to the angle change and the azimuth angle of the supporting shield; obtains the pitch angle and roll angle of the front shield according to the first inclinometer, and the host computer calculates the actual posture of the front shield; The host computer guides the front shield according to the deviation between the actual posture of the support shield and the front shield and the planned line.

9. The guiding method of the double shield guiding system according to claim 8, characterized in that: The host computer determines whether the dual-axis acceleration sensor data has vibration periodicity, and filters the displacement data accordingly; The data of the dual-axis acceleration sensor has no periodicity, so the median filter method is used to filter the data; The data of the dual-axis acceleration sensor changes periodically, and a low-pass filter is used to filter the data.

10. The guiding method of the double shield guiding system according to claim 8, characterized in that: The host computer guides the front shield according to the deviation between the actual posture of the support shield and the front shield and the planned line, which specifically includes the following steps: 1) Obtain all the mileages on the planned line and the three-dimensional coordinate points corresponding to each mileage; 2) According to the distance between the shield machine coordinate point and all the coordinate points on the plan line, select the two plan line coordinate points closest to the shield machine coordinate point from all the distance values, and determine the previous coordinate point and the next coordinate point of the plan line corresponding to the two points according to the mileage elements of the plan line; 3) Calculate the azimuth γ and pitch angle β of the next coordinate point on the plan line relative to the previous coordinate point on the plan line according to the tunneling direction of the shield machine, and set the roll angle α to 0°; 4) Calculate the rotation matrix of the coordinate system with the previous coordinate point of the plan line as the reference point. The calculation method is as follows: 5) Calculate the relative position of the shield machine coordinate point in the coordinate system with the previous coordinate point of the planned line as the reference point. The calculation method is as follows: Among them, (X 盾构机 , Y 盾构机 , Z 盾构机 ) is the shield machine coordinate, ( X 计划线前一坐标点 , Y 计划线前一坐标点 , Z 计划线前一坐标点 ) are the coordinates of the point in front of the shield machine on the planned line; X is the distance between the coordinate point of the shield machine and the previous coordinate point of the plan line. It is used to determine whether the mileage element in the plan line is excavation from a small mileage to a large mileage. If so, the mileage of the coordinate point of the shield machine is the mileage of the previous coordinate point of the plan line plus X. Otherwise, the mileage of the coordinate point of the shield machine is the mileage of the previous coordinate point of the plan line minus X. Y is the horizontal deviation between the coordinate point of the shield machine and the plan line, and Z is the vertical deviation between the coordinate point of the shield machine and the plan line.

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