Coal mining machine inertial navigation system correction method based on coal mining technology

Abstract

The invention discloses a method for correcting an inertial navigation system of a coal mining machine based on a coal mining process, which is applied to the field of inertial navigation correction of the coal mining machine and aims to solve the problem that the inertial navigation correction and the positioning accuracy of the coal mining machine are restricted due to the lack of combination with an underground coal mine fully-mechanized coal mining scene in the correction process in the prior art. According to the invention, the coal mining machine process generally cannot push and slide in a coal sweeping stage and a cutter returning stage, that is, the coal mining machine can repeatedly pass through a section of distance when the advancing distance does not change in a period of time in the fully mechanized coal mining process; therefore, data support can be provided for calibrating the track of the coal mining machine and evaluating the influence on inertial navigation calculation of the walking track in different cutting states. Meanwhile, if sliding pushing and sliding pulling conditions in the coal sweeping stage and the cutter returning stage exist, the centralized control center can timely collect support operation information and send the support operation information to the coal cutter inertial navigation system, and the correction algorithm is stopped.

Description

Technical Field

[0001] The present invention belongs to the field of inertial navigation correction of shearers, and particularly relates to a shearer inertial navigation system correction technology. Background Art

[0002] At present, the precise positioning of shearers in fully mechanized coal mining mostly adopts the combined navigation method of the odometer of the inertial navigation system. The accuracy of correction mainly relies on methods such as Kalman filtering or using dual inertial navigation. These methods rely on the data of the IMU and the odometer data, and have good versatility. However, there is a lack of a method combined with the fully mechanized coal mining scenario in underground coal mines, which restricts the inertial navigation correction and the positioning accuracy of shearers. Summary of the Invention

[0003] To solve the above technical problems, the present invention proposes a correction method for the shearer inertial navigation system based on the coal mining process, which combines the fully mechanized coal mining scenario in underground coal mines to correct the inertial navigation and position the shearer.

[0004] The technical solution adopted by the present invention is: a correction method for the shearer inertial navigation system based on the coal mining process, including:

[0005] S1. After entering the process of cutting triangular coal, when the shearer passes through the preset triangular coal return cutter support number and does not adjust the traction direction of the shearer, the inertial navigation system continuously records and updates the position and attitude of the return cutter point until the traction direction of the shearer is adjusted, and then records the position information DataF of the return cutter point;

[0006] S2. When the shearer is in the triangular coal return cutter stage, record the walking dead reckoning trajectory L1 of the inertial navigation system during the triangular coal return cutter stage of the shearer;

[0007] S3. After entering the process of cutting through coal, when the shearer enters the empty return cutter stage, record the walking dead reckoning trajectory L2 of the inertial navigation system during the empty return cutter stage of the shearer;

[0008] S4. When returning to the return cutter point after completing the empty return cutter, the inertial navigation system performs dead reckoning according to the position information DataF of the return cutter point recorded in step S1;

[0009] S5. When returning to the return cutter point after completing the empty return cutter, it also includes calculating the inertial navigation error correction parameters of the coal cutting state of the shearer according to the trajectory L1 recorded in step S2 and the trajectory L2 recorded in step S3;

[0010] S6. Calculate the corrected trajectory during the subsequent coal cutting state of the shearer according to the correction parameters.

[0011] Advantages of the present invention: In the underground, the inertial navigation uses an odometer for integrated navigation to achieve functions such as attitude calculation of the shearer and coal miner positioning. Generally, the optimization of inertial navigation can only be carried out in aspects such as Kalman filter improvement, without considering the application scenarios of underground fully mechanized mining. The present invention fully combines the coal mining process to optimize the inertial navigation system. Considering the problem that the error of inertial navigation increases with time, the present invention uses the points that do not change periodically (return cut points) for dead reckoning to eliminate the stage error. At the same time, it also considers the influence of the coal cutting state on the inertial navigation trajectory of the shearer, and finds the process section where the trajectory does not change but the coal cutting state changes, providing a basis for correcting the through-cut coal cutting trajectory. Brief Description of the Drawings

[0012] Figure 1 The end entry coal mining process table provided by the embodiment of the present invention;

[0013] Figure 2 The middle entry coal mining process table provided by the embodiment of the present invention;

[0014] Figure 3 The shearer end cut triangular coal process table provided by the embodiment of the present invention;

[0015] Figure 4 The flow chart of the solution of the present invention;

[0016] Figure 5 The coal cutting process flow provided by the embodiment of the present invention;

[0017] Figure 6 The triangular coal process stage flow chart provided by the embodiment of the present invention;

[0018] Figure 7 The through-cut process stage flow chart provided by the embodiment of the present invention. Detailed Embodiment

[0019] To facilitate those skilled in the art to understand the technical content of the present invention, the content of the present invention will be further explained below with reference to the accompanying drawings.

[0020] As Figure 4 shown, in fully mechanized mining, the main coal mining processes include cutting triangular coal, sweeping coal, through-cutting, etc. According to the shearer process, generally, pushing the scraper conveyor is not carried out during the coal sweeping stage and the return cut stage, that is, there is a travel distance that does not change within a certain period of time in the fully mechanized mining process, and the shearer will repeatedly pass through this section of distance, which can provide data support for calibrating the shearer trajectory and evaluating the influence of different cutting states on the inertial navigation dead reckoning walking trajectory. In addition, if the situation of pushing the scraper conveyor and pulling the support appears at the end during the coal sweeping and return cut stages, the centralized control center can timely collect the support operation information and send it to the shearer inertial navigation system to abort the current correction algorithm and wait until the next entry to continue the correction.

[0021] The coal mining processes in fully mechanized coal winning faces are similar in most coal mines. The difference lies in that some coal mines use end cutting while some use middle cutting. However, they all have the processes of triangular coal (including triangular coal cutting and triangular coal returning processes), coal sweeping, and roadway clearing. The states of the coal wall, scraper conveyor, and shearer drum are different under different coal mining processes. The present invention optimizes and corrects the inertial navigation system installed on the shearer according to the position of the cutting scraper conveyor and the change of the drum cutting state after cutting. The following is an application description of the solutions for two types of coal cutting and feeding methods.

[0022] In Figure 1 the head cutting process, the head triangular coal cutting of Process 3 is adopted. After reaching the head turning point, Process 4 is adopted to start returning to cut the triangular coal. After repeatedly sweeping the coal by adopting Process 5, the shearer starts to cut the full roadway towards the tail by adopting Process 6.

[0023] In Figure 1 the head cutting process, when the shearer starts from the head turning point by adopting Process 4 and finally returns to the head turning point by adopting Process 6, the scraper conveyor does not push the trough before the shearer moves. The shearer moves on the same trajectory section throughout the process. The same situation also exists in the tail cutting. This solution collects data in the head-to-triangular coal turning point section in Process 4 and Process 6, calculates the correction parameters after reaching the turning point, and applies them in the subsequent coal mining process.

[0024] In Figure 2 the middle inclined cutting process, the shearer cuts obliquely towards the head in the middle by adopting Process 1. After cutting, it directly cuts the full roadway towards the head by adopting Process 2. It repeatedly sweeps the coal at the head by adopting Process 3, and finally returns to cut the full roadway towards the tail by adopting Process 4. In the middle cutting process, the trough pushing occurs after the shearer returns to cut the full roadway, which means that the trajectory of the shearer does not change during this round trip. This solution collects data in the head-to-triangular coal turning point section in Process 2 and Process 4, calculates the correction function after reaching the turning point, and applies it in the subsequent coal mining process. The driving trajectory from the middle to the tail in Process 4 is also consistent with the trajectory of the shearer driving towards the middle in Process 6, and this solution can be used for correction again.

[0025] Take Figure 3Taking the head end cutting as an example, in process a, the inclined cutting is used to cut the triangular coal and the scraper conveyor is moved; in process b, the triangular coal at the head is returned; in process c, the coal at the head area is swept; in process d, it is the empty return stage when the head cuts through to the tail; in process e, it is the normal coal cutting stage when the head cuts through to the tail. By comparing different process sections, it can be found that both processes b and e will return to the return point. If the previously recorded return point data is directly used in section e, the position error generated during the cutting of triangular coal can be eliminated. At the same time, by comparing process sections b and d, it can be found that the shearer has traveled the same trajectory, but the coal cutting states are different. That is, when returning the triangular coal in section b, the A drum cuts the top coal and the B drum cuts the bottom coal in the normal coal cutting state; when returning the empty cut in section d, since the top and bottom coal cutting has been completed in the previous process, the coal cutting amount can be ignored. The influence of the coal cutting of the shearer on the inertial navigation trajectory calculation when cutting through between the head ends can be optimized by the difference in the walking trajectories calculated by inertial navigation in process sections b and d.

[0026] To achieve the above object, the technical solution of the present invention is: a method for correcting the inertial navigation system of a shearer based on the coal mining process, as Figure 4 shown, including the following steps:

[0027] Step 1. Determine whether to enter the process of cutting triangular coal: Both the support electro-hydraulic control automation manufacturer and the shearer manufacturer can identify the cutting process state, usually based on the support number where the shearer is located and the traction direction of the shearer. At the same time, the shearer driver can also manually adjust the process state. All of the above can be input into the shearer inertial navigation system through the underground data transmission network. At this time, the shearer makes an inclined cut, corresponding to Figure 3 process a.

[0028] Step 2. When the shearer passes through the preset support number for returning the triangular coal and does not adjust the traction direction of the shearer; the inertial navigation continuously records and updates the return position and attitude until the return point position information (DataF) is confirmed after adjusting the traction direction. At this time, the support has completed pushing the scraper conveyor, and the scraper conveyor has come to a relatively straight stage. The shearer adjusts the drum direction to cut coal normally, corresponding to Figure 3 process b.

[0029] Step 3. When the shearer is in the stage of returning the triangular coal, according to the previous analysis, it is necessary to completely record the walking calculation trajectory (trajectory L1) of the inertial navigation system during the stage of the shearer returning the triangular coal; the shearer cuts the coal to the head end, completes the return of the triangular coal, and enters the stage of repeatedly sweeping and cutting the bottom coal, corresponding to Figure 3 process c.

[0030] Step 4. After completing the coal sweeping, the shearer enters the empty return stage. According to the previous analysis, it is also necessary to completely record the walking calculation trajectory (trajectory L2) of the inertial navigation system during the empty return stage of the shearer, corresponding to Figure 3 process d.

[0031] Step 5. After completing the return of the empty cutter to the return cutter point, the shearer starts the normal through-cutting stage. At this time, the position coordinates of the return cutter point recorded in Step 2 are replaced (using DataF for dead reckoning), which can eliminate the dead reckoning error of the inertial navigation system during the return cut of triangular coal, coal sweeping, and return of the empty cutter. At the same time, according to the trajectory errors recorded in Steps 3 and 4, the dead reckoning error caused by coal cutting during the through-cutting stage of the shearer is optimized (the correction parameter A is calculated through the L1 and L2 trajectories).

[0032] When calculating the correction parameter, the difference between the two curves and the travel distance of the shearer are used to fit the function. The principal component analysis (PCA) method is used to fit the linear function in the three-dimensional space, and the travel distance of the shearer is brought into the linear function to calculate the correction value A. (In addition to using PCA, the least squares method can also be used for linear function fitting.) The specific operation steps are as follows:

[0033] (1) Data preprocessing. In the actual operation of the inertial navigation, due to different travel times, the number of stored data points is different, resulting in the points on the L1 curve not being completely corresponding to the points on the L2 curve. At the same time, the starting points of the L1 and L2 trajectories are opposite and coordinate conversion is required. Assume the coordinate points of L1 and L2 are as follows:

[0034] L1 = [P 1_1 , P 1_2 , P 1_3 , ……, P 1_n-2 , P 1_n-1 , P 1_n

[0035] L2 = [P 2_1 , P 2_2 , P 2_3 , ……, P 2_m-2 , P 2_m-1 , P 2_m

[0036] Among them, P 1_n represents the nth coordinate point on the L1 trajectory, and P 2_m represents the mth coordinate point on the L2 trajectory. The values of m and n may not be equal.

[0037] Since the number of coordinate points of the two trajectories is unequal, it is necessary to preprocess the trajectories so that the number of coordinate points corresponds. The L1 and L2 trajectories are evenly divided into k parts according to the connection line between the head and tail points. The value of k is determined by the travel trajectory. Usually, 1 meter is divided into 10 parts. During the equal division process, it is certain that the evenly divided points are not on the existing coordinates of L1 or L2, and they are obtained through linear spline interpolation of adjacent points. After processing, it is expressed as follows:

[0038] L1′ = [P′ 1_1 , P′​​1_2 , P' 1_3 , ……, P' 1_k-2 , P' 1_k-1 , P1' _k

[0039] L2' = [P' 2_1 , P' 2_2 , P' 2_3 , ……, P' 2_k-2 , P' 2_k-1 , P2' _k

[0040] Wherein, L1' and L2' respectively represent the trajectories after processing L1 and L2. P1' _k represents the k-th coordinate point in the L1' trajectory, and P2' _k represents the k-th coordinate point in the L2' trajectory.

[0041] After the above processing, L1' and L2' obtained have the same dimension. At this time, it is necessary to calculate the difference between the two trajectories. However, since the curve trajectory directions represented by L1' and L2' are opposite, that is, when subtracting, the L2' trajectory is reversed and participates in the calculation. The result is shown as follows:

[0042] D i = P2' _k-i - P1' _i

[0043] L = [D1, D2, D3, ……, D k-2 , D k-1 , D k

[0044] Wherein, L represents the coordinate difference data group after subtracting the L1' and L2' trajectories, and D k represents the k-th corresponding difference coordinate point.

[0045] (2) Calculate the error correction function

[0046] When fitting the coordinate data group L in three-dimensional space to a straight line, principal component analysis is used to find the main direction of the data, which is usually consistent with the direction of the best-fit straight line. The work is as follows:

[0047] 1) Calculate the mean point. Given the D of the three-dimensional coordinate points in the data group L i coordinate values are (x i , y i , z i ), first calculate the overall mean coordinate of the coordinate group, using to represent:

[0048] ​​​

[0049] 2) Centralized coordinates: Subtract the mean point from each coordinate point to obtain the centralized coordinate points (x i ′, y i ′, z i ′):

[0050]

[0051] 3) Construct the covariance matrix: Use the centralized coordinate points to construct a 3×3 covariance matrix C:

[0052]

[0053] 4) Perform eigenvalue decomposition on the covariance matrix C to find the largest eigenvalue λ max and the corresponding eigenvector v = (v x , v y , v z ). This eigenvector is the direction vector of the best - fitting line.

[0054] 5) Using the mean point and the direction vector v, the parametric equation of the fitting line can be expressed as:

[0055]

[0056] where x, y, and z represent the dependent variables of the fitting line function, and t is the independent variable of the fitting line function, representing the traveling distance of the shearer in the scenario of the present invention.

[0057] (3) Correction of the output trajectory coordinates

[0058] Calculate the straight - line equation through the above formula. When the shearer is in the coal - cutting state, calculate the correction amounts A in the three coordinate directions according to the traveling distance s within the stage to be corrected, and add the correction amounts to the dead - reckoning result to obtain the corrected coordinates, which are expressed as follows:

[0059] A = [A x , A y , A z

[0060]

[0061] where A is the coordinate correction amount, P is the coordinate output by the inertial navigation system, is the corrected coordinate value.

[0062] Step 6. After the shearer finishes cutting a full pass, it enters the coal - sweeping stage at the end. After the coal - sweeping is completed, it enters the triangular - coal process section of the new stage, and repeats step (1) to start a new round of cycle. ​

[0063] Through the above explanations, the entire coal cutting process flow is as follows Figure 5 shown. The correction scheme mainly participates in two stages. The first stage is the triangular coal cutting process section; the second stage is the full cut process section. The participation process of the first stage is as follows Figure 6 shown. As the shearer moves, the coal mining process changes from triangular coal entry cut to triangular coal return cut. The main tasks are: 1. Record the position information DataF of the return cut point; 2. Record the triangular coal return cut trajectory L1. The participation flow chart of the second stage is as follows Figure 7 shown. The main tasks of this stage are: 1. Record the trajectory L2 during the empty return cut stage; 2. Use DataF for dead reckoning at the return cut point; 3. Calculate the inertial navigation error correction parameter A of the coal shearer cutting coal state through L1 and L2; 4. Use the correction parameter A to correct the subsequent trajectory.

[0064] Those of ordinary skill in the art will realize that the embodiments described herein are for helping the reader understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A method for correcting an inertial navigation system of a coal mining machine based on coal mining technology, characterized in that: include: S1. After entering the triangular coal cutting process, when the coal mining machine passes through the preset triangular coal return cutter bracket number and the traction direction of the coal mining machine is not adjusted, the inertial navigation system continuously records and updates the position and posture of the return cutter point until the traction direction of the coal mining machine is adjusted, and records the return cutter point position information DataF; S2, when the coal mining machine is in the triangular coal return stage, record the walking and extrapolation trajectory L1 of the inertial navigation system in the triangular coal return stage of the coal mining machine; S3, after entering the cutting process, when the coal mining machine enters the empty knife return stage, record the walking and extrapolation trajectory L2 of the inertial navigation system in the empty knife return stage of the coal mining machine; S4, when the knife returns to the knife return point after returning to the empty knife, the inertial navigation system performs dead reckoning according to the knife return point position information DataF recorded in step S1; S5, when the return of the empty cutter to the return cutter point is completed, it also includes calculating the inertial guidance error correction parameter of the coal cutting state of the coal mining machine according to the trajectory L1 recorded in step S2 and the trajectory L2 recorded in step S3; S6. Calculate the correction trajectory of the subsequent coal mining machine in the coal cutting state according to the correction parameters.

2. A method for correcting the inertial navigation system of a coal mining machine based on coal mining technology according to claim 1, characterized in that: The implementation process of step S5 includes the following steps: S51, converting the trajectory L1 and the trajectory L2 to the same dimension after preprocessing; then obtaining a coordinate difference data set L by calculating the difference between the two trajectories in the same dimension; S52, fitting a straight line function according to the coordinate difference data set L; S53, substituting the travel distance of the coal mining machine into the linear function to calculate the correction value A.

3. A method for correcting an inertial navigation system of a coal mining machine based on coal mining technology according to claim 2, characterized in that: The specific process of step S51 is as follows: S511, record the trajectory L1 as: L1=[P 1_1 ,P 1_2 ,P 1_3 ,……,P 1_n-2 ,P 1_n-1 ,P 1_n ] The trajectory L2 is recorded as: L2=[P 2_1 ,P 2_2 ,P 2_3 ,……,P 2_m-2 ,P 2_m-1 ,P 2_m ] Among them, P 1_n represents the nth coordinate point in the L1 trajectory, P 2_m Represents the mth coordinate point in the L2 trajectory; S512: If n and m are not equal, execute step S513; otherwise, execute step S514; S513, respectively divide the track L1 and the track L2 into k parts according to the connection line between the first and last points; the processed track L1 and track L2 are expressed as: L1′=[P′ 1_1 ,P′ 1_2 ,P′ 1_3 ,……,P′ 1_k-2 ,P′ 1_k-1 ,P1′ _k ] L2′=[P′ 2_1 ,P′ 2_2 ,P′ 2_3 ,……,P′ 2_k-2 ,P′ 2_k-1 ,P2′ _k ] Among them, L1′ and L2′ represent the trajectories processed by L1 and L2 respectively; P1′ _k represents the kth coordinate point in the L1′ trajectory, P2′ _k represents the kth coordinate point in the L2′ trajectory; S514, subtract the two trajectories to obtain a coordinate difference data set; specifically: the two trajectories are in opposite directions, and when subtracting, the subtracted trajectory is reversed to participate in the calculation.

4. A method for correcting an inertial navigation system of a coal mining machine based on coal mining technology according to claim 2 or 3, characterized in that: Step S52 uses principal component analysis or least squares method to perform straight line function fitting.

5. A method for correcting the inertial navigation system of a coal mining machine based on coal mining technology according to claim 4, characterized in that: The implementation process of linear function fitting using principal component analysis is as follows: 1) Calculate the mean point, given the three-dimensional coordinate point D in the data set L i The coordinate value is (x i ,y i ,z i ), first calculate the overall mean coordinate of the coordinate group, using express: Where k represents the total number of coordinate points in the data set L; 2) Centralize the coordinates. Subtract the mean coordinate from each coordinate point to get the centralized coordinate point (x i ′,y i ′,z i ′): 3) Construct a covariance matrix and use the centralized coordinate points to construct a 3×3 covariance matrix C: 4) Perform eigenvalue decomposition on the covariance matrix C and find the largest eigenvalue λ max The corresponding eigenvector v=(v x ,v y ,v z ); 5) Use mean points and the eigenvector v, the parametric equation of the fitted line is expressed as: Among them, x, y, z represent the dependent variables of the fitted straight line function, and t is the independent variable of the fitted straight line function.

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