Evaluation Method for the Straightness of the Comprehensive Mining Face Space under Complex Coal Seam Conditions

Abstract

The present invention relates to an evaluation method for the spatial straightness of a fully mechanized mining face under complex coal seam conditions. Based on the influence of coal seam undulations on the spatial straightness of the fully mechanized mining face, according to the motion characteristics of the scraper conveyor during the advancing process and the influence of coal seam undulations on the trajectories of the scraper conveyor and the hydraulic support group, by analyzing the spatial straightness density of the equipment group trajectories, a spatial straightness evaluation model is respectively established, taking into account the influence of the motion characteristics of the floating connection mechanism between the hydraulic support group and the scraper conveyor on the coordinated advancement of the fully mechanized mining face, and realizing the analysis of the spatial straightness of the fully mechanized mining face under complex coal seam conditions based on the factors affecting the coordinated advancement between the equipment in the fully mechanized mining face.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining control, and specifically, to an evaluation method for the spatial straightness of a fully mechanized coal mining face under coal seam conditions. Background Art

[0002] The straightness of a fully mechanized coal mining face plays an important role in ensuring the production efficiency and safety of coal mines. If the straightness cannot be well satisfied, the cutting resistance of the shearer and the running resistance of the scraper conveyor will be greatly increased, shortening the service life of the equipment and seriously leading to serious production accidents. With the development of coal mine intelligentization, the coal seam transparency technology has also made certain progress. The requirement for the "three-level and one-straight" of the fully mechanized coal mining face has been upgraded from two-dimensional space to three-dimensional space during the mining process. However, the current description of the spatial straightness of the fully mechanized coal mining face is still relatively vague. Therefore, it is necessary to combine the influence of coal seam undulation and propose a method to describe the straightness of the fully mechanized coal mining face during the entire mining process from three-dimensional space.

[0003] The patent document with the application number 202111399857.1 defines the spatial straightness of a hydraulic support group, obtains the point cloud of the hydraulic support by using a three-dimensional lidar, extracts the key point set of the hydraulic support by using relevant point cloud processing algorithms, and realizes the measurement of the spatial straightness of the hydraulic support group by using the method of fitting a spatial straight line by the least squares method and calculating the distance error.

[0004] The patent document with the application number 202011070660.9 discloses a straightness detection device for a hydraulic support and its working method. By installing an additional device, a linear slide rail and a pulley assembly, on the hydraulic support, and installing a displacement sensor on one side of the linear slide rail to detect the sliding position of the pulley on the linear slide rail, the straightness detection of the hydraulic support on the working face can be realized by detecting the position of the pulley assembly on the hydraulic support.

[0005] The patent document with the application number 201710442811.0 discloses a method for measuring the pose and straightness of an underground hydraulic support group based on a multi-image sequence. Square positioning marks are placed on the hydraulic support, the target image of the hydraulic support is collected by a camera, and the positioning marks in the preprocessed image are extracted; the edge straight lines of each positioning mark are fitted, the normal vector of each positioning mark is calculated, and the pose of each hydraulic support is determined by the normal vector; then the straightness of the hydraulic support group is calculated through the relationship between the positioning mark and the scraper.

[0006] The patent document with the application number 201711232670.6 provides a vision-based straightness detection method for fully mechanized mining faces. A vision system is mounted on the fast inspection platform of the working face. During the fast movement of the inspection platform, a video is taken, and it is ensured as stably as possible that the track of the walking mechanism of the inspection platform always appears in the captured image. When the walking mechanism of the inspection platform moves along the working face in a loop at a relatively high speed, the track of its movement is captured, and then the movement track of the walking mechanism of the inspection platform is calculated based on vision algorithms, thereby detecting the straightness of the fully mechanized mining face and realizing the automatic straightening of the fully mechanized mining face.

[0007] The deficiencies in the above research are as follows: 1) When studying the straightness of fully mechanized mining faces, most consider the definition and control of the straightness of a single equipment group, and the consideration of the overall straightness from the coordination between multiple levels of equipment is not comprehensive enough. 2) When currently analyzing and researching the straightness of fully mechanized mining faces, most are carried out under ideal coal seam conditions, and analyzing the straightness under complex coal seam conditions is closer to the actual working conditions. 3) When considering the influence of coal seam undulations on the straightness of fully mechanized mining faces, the analysis of the straightness of fully mechanized mining faces also needs to transition from two-dimensional space to three-dimensional space to establish a straightness model of fully mechanized mining faces in three-dimensional space. Therefore, considering the influence of coal seam undulations, analyze the straightness of fully mechanized mining faces and establish an evaluation model for the spatial straightness of fully mechanized mining faces under complex coal seam conditions. Summary of the Invention

[0008] The object of the present invention is to provide an evaluation method for the spatial straightness of fully mechanized mining faces under complex coal seam conditions. Aiming at the problem of spatial straightness during the advancement of fully mechanized mining faces under complex coal seam conditions, establish an evaluation model for the spatial straightness of fully mechanized mining faces from a three-dimensional perspective and analyze the spatial straightness of fully mechanized mining faces. According to the coal seam undulation situation determined by coal seam detection information, segment the coal seam, and analyze the spatial straightness of the hydraulic support group and the scraper conveyor from the direction of the shearer's movement and the advancement direction of the fully mechanized mining face, so as to realize the evaluation of the overall spatial straightness during the operation of the fully mechanized mining face.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] An evaluation method for the spatial straightness of fully mechanized mining faces under complex coal seam conditions, comprising:

[0011] Step 1, detect the coal seam undulation at the initial stage of the fully mechanized mining face, and segment the coal seam according to the coal seam undulation situation determined by the detection data;

[0012] Step 2, establish an evaluation model for the spatial straightness of the scraper conveyor for each discrete coal seam segment, including:

[0013] (1) Establish the geometric model of the scraper conveyor trajectory and (2) establish the discrete spatial pose error model of the scraper conveyor;

[0014] Among them, the discrete spatial pose error model of the scraper conveyor includes:

[0015] ① The spatial straightness error model of the scraper conveyor along the walking direction of the shearer, which obtains the lateral propulsion spatial straightness error density ρ of the scraper conveyor s ,

[0016] and ② the spatial direction error model of the scraper conveyor along the overall propulsion direction of the fully mechanized coal mining face, which obtains the longitudinal propulsion spatial straightness error density ρ of the scraper conveyor d ;

[0017] Step 3: Establish the spatial straightness evaluation model of the hydraulic support group for each discrete coal seam section, including:

[0018] (1) Establish the geometric model of the hydraulic support group trajectory and (2) establish the discrete spatial pose error model of the hydraulic support group;

[0019] Among them, the discrete spatial pose error model of the hydraulic support group includes:

[0020] ① The spatial straightness error model of the hydraulic support group along the walking direction of the shearer, which obtains the lateral propulsion spatial straightness error density ρ representing the hydraulic support group s H ,

[0021] and ② the spatial direction error model of the hydraulic support group along the overall propulsion direction of the fully mechanized coal mining face, which obtains the longitudinal propulsion spatial straightness error density ρ representing the hydraulic support group d (H) ;

[0022] Step 4: Establish the spatial straightness evaluation model of the fully mechanized coal mining face for each discrete coal seam section;

[0023] Based on the construction of the spatial straightness evaluation model of the scraper conveyor and the spatial straightness evaluation model of the hydraulic support group, the spatial straightness of the overall fully mechanized coal mining face is defined by combining the motion characteristics of the floating connection mechanism; when the propulsion spatial straightness error density of the hydraulic support group and the scraper conveyor, and the pushing pose consistency index ρ of the floating connection mechanism between the scraper conveyor and the hydraulic support group F meet Equation (23), the fully mechanized coal mining face meets the spatial straightness requirements during mining;

[0024]

[0025] Step 5: Analyze the spatial straightness of the fully mechanized coal mining face for the whole coal seam;

[0026] Perform splicing analysis on the straightness error density of the propulsion space of the hydraulic support groups corresponding to each discrete coal seam body, the scraper conveyor, and the consistency index of the pushing posture of the floating connection mechanism between the scraper conveyor and the hydraulic support groups, and finally obtain the requirements for the straightness of the fully-mechanized coal mining face space for the entire coal seam as shown in formula (27):

[0027]

[0028] where represents the discrete coal seam section at the intersection of the peak and bottom of the coal seam, represents the discrete coal seam section without considering the intersection of the peak and bottom of the coal seam, and s represents the coal seam section where it is located.

[0029] Furthermore, in step one, based on the detection data, perform processing through interpolation and prediction to obtain the coal seam trajectory curve F(x, y, z) = 0; the method for dividing the coal seam section is: along the x-axis direction, use the peak-bottom point of the coal seam curve as the division point for division, analyze the partial derivative of the coal seam trajectory curve, take the partial derivative with respect to the x direction, and then analyze the posture of the scraper conveyor on the divided coal seam section; the coal seam division principle is as shown in the formula:

[0030]

[0031] ∑ represents the coal seam surface, x represents the serial number of the coal seam points collected along the coal seam strike, y represents the overall advancement amount of the fully-mechanized coal mining face along the coal seam dip direction, and z represents the height of the coal seam in the specified coordinate system o-xyz.

[0032] Furthermore, in step two, the method for establishing the geometric model of the scraper conveyor trajectory is:

[0033] Establish an absolute reference coordinate system {O(x, y, z)} at the intersection of the roadway and the fully-mechanized coal mining face, and establish a family of local reference coordinate systems on each middle trough

[0034] The coordinate system during the advancement process of the scraper conveyor is a three-level system, {O} is the absolute coordinate system, is the overall advancement coordinate system, is the local reference coordinate system, k is the number of advancement times, and i is the middle trough serial number; the pose changes along the advancement direction of the middle trough A of the scraper conveyor i and along the cutting direction of the shearer are respectively represented by the vectors and respectively, and the attitude angles of the middle trough relative to the overall advancement coordinate system are (α j , β j , γ j ), then the middle trough A of the scraper conveyor jRelative to the overall propulsion coordinate system The discrete trajectory is represented as Γ t , and the formula is as follows:

[0035]

[0036] The coordinate trajectory of each middle trough relative to the overall propulsion coordinate system is represented by R i , and the local reference coordinate system relative to the overall propulsion coordinate system has the coordinates [R 0j is the angle transformation matrix of the local reference coordinate system relative to the overall propulsion coordinate system ;

[0037] In the local reference coordinate system, for a straight line passing through an arbitrary point parallel to the axis of the middle trough in the transverse propulsion direction, the dihedral angle in the direction of this straight line is (α j ′, β j ′), and the unit vector of this straight line in the local reference coordinate system is represented by p j ;

[0038] p j = [sinα j 'cosβ j ′, sinα j 'sinβ j ′, cosα j ′] T , (j = 1…n) (4)

[0039] In summary, the discrete trajectories of each middle trough in the overall propulsion coordinate system form a discrete surface ∑ t with Γ i as the discrete directrix and p St as the generatrix;

[0040]

[0041] where n is the number of discrete units of the scraper conveyor, that is, the number of middle troughs, and j is the jth middle trough.

[0042] Furthermore, in step two, the method for establishing the spatial straightness error model of the scraper conveyor along the walking direction of the shearer is as follows:

[0043] In the overall propulsion coordinate system, the difference between the discrete curve segment set and the corresponding fitted ideal straight line is the spatial straightness error, which is used as an evaluation index for measuring the spatial straightness of the scraper conveyor;

[0044]

[0045] where R l 0 is the point corresponding to the fitting ideal straight line of the discrete point set of the scraper conveyor in the coordinate system below, p2 is the pose information of the point on the middle trough in the local reference coordinate system, and x is the parametric model of each middle trough in the local reference coordinate system is the spatial straightness error, and R j is the point on the discrete trajectory in the absolute coordinate system, and R0 is the coordinate in the absolute coordinate system ;

[0046] Define the rotating body with the discrete surface of the scraper conveyor as the symmetry plane as the standard discrete body; the rotating body with the fitting ideal straight line as the axis and the discrete reference lines of each middle trough as the generatrix as the error discrete body; define the spatial straightness error density ρ s of the transverse advancement of the scraper conveyor as the mass-volume ratio of the error discrete body to the standard discrete body, and the specific definition is shown in formula (8):

[0047]

[0048] The spatial straightness error density ρ s of the transverse advancement of the scraper conveyor reflects the average spatial straightness error of the scraper conveyor. The smaller the ρ s value, the better the spatial straightness of the scraper conveyor.

[0049] Furthermore, in step two, the method for establishing the spatial direction error model of the scraper conveyor along the overall advancement direction of the fully mechanized coal mining face is as follows:

[0050] Describe it with a spherical curve, and convert the unit vector of any straight line represented by to the overall advancement coordinate system below, and the trajectory of the vector end point is located on the same spherical surface and is expressed in the fixed coordinate system as:

[0051]

[0052] During the advancement of the scraper conveyor, there is a direction that makes the radius of the enveloping sphere the smallest. Define this direction as the minimum error direction during longitudinal advancement. At this time, the spatial straightness of the scraper conveyor is least affected by the undulation of the cutting floor along the coal seam dip direction. According to this direction, obtain the direction error model ΔS d of the entire scraper conveyor in the advancement direction of the fully mechanized coal mining face as follows:

[0053]

[0054] where x is the least dihedral angle parameter relative to the absolute reference coordinate system {o; x; y; z}, is the dihedral angle corresponding to the middle groove of each section (δ1 (j) , δ2 (j) ) parameter of the vector, ΔS d is the direction error model of the entire scraper conveyor in the advancing direction of the fully mechanized coal mining face, and the minimum direction error model is ΔS d (x);

[0055] After establishing the direction error model ΔS d for the discrete point set, determine the straightness error density ρ d of the longitudinal advancing space of the scraper conveyor, ρ d is defined as the ratio of the mass of the spherical direction error to the area of the sphere, as shown in formula (11),

[0056]

[0057] The straightness error density ρ d of the longitudinal advancing space of the scraper conveyor reflects the influence degree of the undulation of the coal seam floor on the pitching attitude of the scraper conveyor. The smaller the ρ d value, the smaller the influence of the undulation of the coal seam floor on the spatial straightness of the scraper conveyor.

[0058] Furthermore, in step three, the method for establishing the geometric model of the hydraulic support group trajectory is as follows:

[0059] Under the absolute reference coordinate system {o; x; y; z} established at the intersection of the roadway and the working face, establish a local reference coordinate system family {o iH ; x iH ; y iH ; z iH} at the centroid position when each hydraulic support is fully supported;

[0060] The coordinate system during the advancement of the hydraulic support group is a three-level system, {O} is the absolute coordinate system, is the overall advancement coordinate system of the hydraulic support group, is the local reference coordinate system; the pose changes along the advancing direction of a single hydraulic support and along the cutting direction of the shearer are represented by vectors and respectively. The attitude angles of a single hydraulic support H j relative to the overall advancement coordinate system are (α j H , β j H , γ j H ), then a single hydraulic support H jRelative to the overall advancing coordinate system The discrete trajectory is represented as Γ t (H) , and the formula is as follows:

[0061]

[0062] The coordinate trajectories of each hydraulic support relative to the overall advancing coordinate system are represented by , and the local reference coordinate system relative to the overall advancing coordinate system has coordinates of [R 0j H is the local reference coordinate system relative to the overall advancing coordinate system angle transformation matrix;

[0063] In the local reference coordinate system, it is also necessary to describe the attitude of each hydraulic support. The dihedral angle in the direction of the straight line passing through any point parallel to the center line of the base of the hydraulic support along the transverse advancing direction is (α j ' (H) , β j ' (H) ), and the unit vector of this straight line in the local reference coordinate system is represented by p i ,

[0064] p j (H) = [sinα j ' (H) cosβ j ' (H) , sinα j ' (H) sinβ j ' (H) , cosα j ' (H) T , (j = 1…n) (14)

[0065] In summary, the discrete trajectories of each hydraulic support in the overall advancing coordinate system form a discrete surface ∑S t H with Γ j (H) as the discrete directrix and p t H .

[0066]

[0067] where n is the number of discrete units of the hydraulic support, that is, the number of middle troughs, and j is the jth hydraulic support. ​

[0068] Furthermore, in step three, the method for establishing the spatial straightness error model of the hydraulic support group along the traveling direction of the shearer is as follows:

[0069] In the overall advancement coordinate system, the difference between the discrete curve segment set and the corresponding fitted ideal straight line is the spatial straightness error, which can be used as an evaluation index for measuring the spatial straightness of the hydraulic support group;

[0070]

[0071] where R l 0(H) is the point corresponding to the fitted ideal straight line of the discrete point set of the hydraulic support in the coordinate system , p2 H is the pose information of the point on the middle trough in the local reference coordinate system, x is the parametric model of each middle trough in the local reference coordinate system, is the spatial straightness error, R H j is the point on the discrete trajectory in the absolute coordinate system, R0 (H) is in the absolute coordinate system coordinates;

[0072] Define the rotating body with the discrete surface at the center of gravity position of a single hydraulic support as the symmetric surface as the standard discrete body of the hydraulic support; the rotating body with the ideal fitted straight line as the axis and the discrete directrix of each hydraulic support as the generatrix is the error discrete body of the hydraulic support; define the spatial straightness error density ρ s H of the hydraulic support group in the transverse advancement direction as the mass-volume ratio of the error discrete body of the hydraulic support to the standard discrete body of the hydraulic support, and the specific definition is shown in formula (18):

[0073]

[0074] The spatial straightness error density ρ s H of the hydraulic support group in the transverse advancement direction reflects the average spatial straightness error of the hydraulic support group and also reflects the overall spatial straightness characteristics of the hydraulic support group; the smaller the ρ s H value, the better the spatial straightness of the hydraulic support group.

[0075] Furthermore, in step three, the method for establishing the spatial direction error model of the hydraulic support group along the overall advancement direction of the fully mechanized coal mining face is as follows:

[0076] Describe it using a spherical curve, and convert the unit vector of any straight line represented to the overall advancement coordinate system Under the condition, the trajectories of the vector endpoints are all located on the same spherical surface. In the fixed coordinate system, it is shown as:

[0077]

[0078] During the advancement of the hydraulic support group, there is a direction in which the radius of the spherical curve is the smallest. This direction is defined as the minimum error direction when the hydraulic support group advances longitudinally. At this time, the spatial straightness of the hydraulic support group is least affected by the undulation of the cut floor in the direction along the coal seam dip. According to this direction, the direction error model ΔS of the entire hydraulic support group in the advancing direction of the fully mechanized coal face is obtained. d (H) As follows:

[0079]

[0080] Where x is the least square dihedral angle parameter relative to the absolute reference coordinate system {o; x; y; z}. is the vector under the dihedral angle (δ1 (j)H , δ2 (j)H ) parameter, and ΔS d (H) is the direction error model of the entire hydraulic support group in the advancing direction of the fully mechanized coal face. The minimum direction error model is ΔS d (H) (x);

[0081] After establishing the direction error model ΔS for the hydraulic support, d (H) the straightness error density ρ of the longitudinal advancement space of the hydraulic support group is determined. d (H) , ρ d (H) is defined as the ratio of the mass of the spherical direction error to the area of the spherical surface, as shown in formula (21).

[0082]

[0083] The straightness error density ρ of the longitudinal advancement space of the hydraulic support group d (H) reflects the influence degree of the undulation of the coal seam floor on the pitching attitude of the hydraulic support group. The smaller the value of ρ d (H) , the smaller the influence of the undulation of the coal seam floor on the spatial straightness of the hydraulic support group.

[0084] Further, in step four, the movement of the floating connection mechanism includes the elongation of the piston rod, the yaw movement and pitch movement of the push rod, and the yaw movement of the connecting head. On the basis of ensuring the spatial straightness of the hydraulic support and the scraper conveyor, the overall spatial straightness of the hydraulic support group and the scraper conveyor can be obtained according to the movement characteristics of the floating connection mechanism. Through the overall movement characteristics M<d i , θ2, θ3, θ4> evaluation, where d i represents the displacement of the piston rod in the floating connection mechanism, θ2 represents the pitch angle of the push rod, θ3 represents the yaw angle of the push rod, and θ4 represents the yaw angle of the connecting head, as shown in formula (22),

[0085]

[0086] ρ F represents the consistency index of the displacement pose of the floating connection mechanism between the scraper conveyor and the hydraulic support group. The value of this index ranges between 0 and 1, reflecting the similarity of the trajectories of the hydraulic support group and the scraper conveyor with respect to spatial straightness. The larger the ρ F value, the more consistent the spatial straightness of the hydraulic support group and the scraper conveyor, and it also indicates a higher degree of satisfaction with the overall spatial straightness of the hydraulic support group and the scraper conveyor.

[0087] Further, in step five, on the basis that the spatial straightness of the fully-mechanized coal mining face corresponding to each discrete coal seam body is satisfied, m middle troughs and the corresponding hydraulic supports are selected separately from both sides of the peak bottom point of the coal seam to analyze the overall spatial straightness of the fully-mechanized coal mining face. Among them, the peak bottom point satisfies formula (24):

[0088]

[0089] Select m middle troughs and the corresponding hydraulic supports separately from both sides of the peak bottom point of the coal seam. Use formulas (8), (11), (18), (21), and (22) to obtain the lateral propulsion spatial straightness error density ρ s of the scraper conveyor at the splicing point of the two discrete coal seam segments at the peak bottom point of the coal seam, the longitudinal propulsion spatial straightness error density ρ d of the scraper conveyor, the lateral propulsion spatial straightness error density ρ s H of the hydraulic support group, the longitudinal propulsion spatial straightness error density ρ d (H) of the hydraulic support group, and the consistency index ρ F of the displacement pose of the floating connection mechanism between the scraper conveyor and the hydraulic support group, as shown in formula (25),

[0090]

[0091] The value of m is determined according to the number of equipment a laid in the discrete coal seam section and the number of middle troughs b involved when the shearer cuts the triangular coal, and m = max(a, b);

[0092] Judge the spatial straightness accuracy of the fully mechanized coal mining face at the peak bottom point according to the calculation results.

[0093]

[0094] If the key parameter values of the spatial straightness of the trajectories of the scraper conveyor and the hydraulic support group in the coal seam after the peak bottom splicing during the mining process meet the formula (26), then the fully mechanized coal mining face meets the spatial straightness requirements.

[0095] The present invention proposes a description method for the spatial straightness of a fully mechanized coal mining face under complex coal seam conditions, and its advantages and outstanding innovation points are as follows:

[0096] (1) Based on the influence of the coal seam undulation on the spatial straightness of the fully mechanized coal mining face, the influence of the shearer cutting and the coal seam undulation on the spatial straightness of the fully mechanized coal mining face is analyzed respectively from the direction of the shearer cutting the coal wall and the overall advancing direction of the fully mechanized coal mining face, and a spatial straightness evaluation model is established, laying a theoretical foundation for the research on straightening the fully mechanized coal mining face under complex coal seam conditions.

[0097] (2) Fully consider the motion characteristics of the scraper conveyor during the advancing process and the influence of the coal seam undulation on the trajectories of the scraper conveyor and the hydraulic support group. By analyzing the spatial straightness density of the trajectories of the equipment group, spatial straightness evaluation models are established respectively, giving full play to the role of the spatial straightness of the scraper conveyor and the spatial straightness of the hydraulic support group as important analysis criteria for the spatial straightness of the fully mechanized coal mining face.

[0098] (3) Take into account the influence of the motion characteristics of the floating connection mechanism between the hydraulic support group and the scraper conveyor on the coordinated advancement of the fully mechanized coal mining face. On the basis of analyzing the spatial straightness of the hydraulic support group and the scraper conveyor, evaluate the spatial straightness of the fully mechanized coal mining face by evaluating the motion characteristics of the floating connection mechanism, realizing the analysis of the spatial straightness of the fully mechanized coal mining face under complex coal seam conditions based on the factors affecting the coordinated advancement between the equipment in the fully mechanized coal mining face.

[0099] (4) Establish a spatial straightness analysis model at the transition of the equipment trajectories of the fully mechanized coal mining face at the peak bottom of the coal seam. By combining the spatial straightness analysis models of the fully mechanized coal mining face in each discrete coal seam section, an analysis model for the spatial straightness of the fully mechanized coal mining face covering the entire coal seam undulation condition is established, which provides an evaluation standard for ensuring the "three-level and one-straight" of the fully mechanized coal mining face. Brief Description of the Drawings

[0100] Figure 1Analysis framework for the spatial straightness of fully mechanized coal mining face;

[0101] Figure 2 Schematic diagram of coal seam parameterization;

[0102] Figure 3 Schematic diagram of the geometric model of the scraper conveyor trajectory for discrete coal seam segments;

[0103] Figure 4 Schematic diagram for the analysis of the discrete spatial pose error model of the scraper conveyor for discrete coal seam segments;

[0104] Figure 5 Schematic diagram of the geometric model of the trajectory of the hydraulic support group for discrete coal seam segments;

[0105] Figure 6 Schematic diagram for the analysis of the discrete spatial pose error of the hydraulic support group for discrete coal seam segments;

[0106] Figure 7 Schematic diagram for the analysis of the spatial straightness evaluation model of the fully mechanized coal mining face for discrete coal seam segments;

[0107] Figure 8 Schematic diagram for the analysis of the spatial straightness evaluation model of the fully mechanized coal mining face at the peak and bottom of the coal seam. Specific implementation manners

[0108] The technical solution of the present invention will be further described in more detail below in conjunction with specific implementation manners. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0109] As Figure 1 shown is the analysis framework for the spatial straightness of the fully mechanized coal mining face. On the basis of realizing coal seam parameterization, the coal seam is segmented according to the undulation of the coal seam. The spatial straightness of the hydraulic support group and the scraper conveyor is analyzed respectively on each discrete coal seam segment, and on this basis, the spatial straightness of the fully mechanized coal mining face is analyzed in combination with the motion characteristics of the floating connection mechanism between the hydraulic support group and the scraper conveyor. Finally, considering the spatial straightness of the equipment group at the peak and bottom of the coal seam, the spatial straightness of the whole fully mechanized coal mining face is analyzed. The specific process is as follows:

[0110] Step 1: Method for segmenting the undulation of the coal seam

[0111] During the formation of coal seams, due to factors such as crustal movement, when there is an inclination in the coal seam floor, there may be complex geology such as undulations. Due to the long length of the fully mechanized mining face and the influence of the undulations along the coal seam dip, when analyzing the spatial pose of the scraper conveyor, the long laying length of the scraper conveyor and the coal seam undulations will result in large errors in direct pose analysis. As Figure 2 shown, at the initial stage of mining in the fully mechanized mining face, a detection of the coal seam undulations will be carried out. According to the detection data, it will be processed through interpolation and prediction to obtain the coal seam trajectory curve F(x, y, z) = 0. Method for dividing coal seam segments: Divide along the x-axis direction with the peak bottom points of the coal seam curve as the dividing points. By analyzing the partial derivatives of the coal seam trajectory curve, taking the partial derivative with respect to the x direction, and then analyzing the pose of the scraper conveyor on the divided coal seam, the division principle is as shown in the formula.

[0112]

[0113] ∑ represents the coal seam surface, x represents the serial number of the coal seam points collected along the coal seam strike, y represents the overall advancement amount of the fully mechanized mining face along the coal seam dip direction, and z represents the height of the coal seam under the specified coordinate system o-xyz. The present invention selects any divided coal seam segment for analysis of the spatial straightness model of the scraper conveyor.

[0114] Step 2: Establishment of the straightness evaluation model of the scraper conveyor for each discrete coal seam segment

[0115] ⑴ Establishment of the geometric model of the scraper conveyor trajectory

[0116] As Figure 3 shown, an absolute reference coordinate system {o; x; y; z} is established at the junction of the roadway and the working face, and a local reference coordinate system family {o i ; x i ; y i ; z i} is established on each middle trough.

[0117] The geometric model of the scraper conveyor trajectory is a model for describing the pose of the scraper conveyor, and the spatial pose of the scraper conveyor is represented by discrete surfaces and lines. The coordinate system during the advancement process of the scraper conveyor is a three-level system, {O} is the absolute coordinate system, is the overall advancement coordinate system, [[ID= 36]]is the local reference coordinate system. The pose changes along the advancement direction of the middle trough A i and along the cutting direction of the shearer are respectively represented by vectors and respectively, and the attitude angle of the middle trough relative to the overall advancement coordinate system is (α j , βj , γ j ), then the middle trough A of the scraper conveyor j with respect to the overall propulsion coordinate system has a discrete trajectory represented as Γ t , and the formula is as follows:

[0118]

[0119] The coordinate trajectories of each middle trough with respect to the overall propulsion coordinate system are represented by R i , and the local reference coordinate system with respect to the overall propulsion coordinate system has coordinates [R 0j is the angle transformation matrix of the local reference coordinate system with respect to the overall propulsion coordinate system .

[0120] In the local reference coordinate system, it is also necessary to describe the attitude of each middle trough. The straight line passing through an arbitrary point parallel to the axis of the middle trough along the transverse propulsion direction has a dihedral angle of (α j ′, β j ′) in the direction of this straight line, and the unit vector of this straight line in the local reference coordinate system is represented by p j .

[0121] p j = [sinα j ′ cosβ j ′, sinα j ′ sinβ j ′, cosα j ′] T , (i = 1…n) (4)

[0122] In summary, the discrete trajectories of each middle trough in the overall propulsion coordinate system form a discrete surface ∑ t with Γ j as the discrete directrix and p St .

[0123]

[0124] where n is the number of discrete units of the scraper conveyor, i.e., the number of middle troughs, and j is the jth middle trough section.

[0125] ⑵ Establishment of the discrete spatial pose error model of the scraper conveyor

[0126] ① Spatial straightness error model of the scraper conveyor along the shearer travel direction (transverse propulsion)

[0127] As Figure 4As shown in a of , the selected discrete coal seam section S i When the scraper conveyor is pushed under ideal conditions, the trajectory of the scraper conveyor is an ideal straight line. However, in actual situations, due to the undulation of the coal seam and the pushing error of the pushing mechanism of the hydraulic support, the trajectory of the scraper conveyor approximately presents the form of a space curve. Due to the gap between adjacent two sections during the connection of the middle troughs, the trajectory of the scraper conveyor appears as a set of discrete curve segments that are not collinear in the space position.

[0128] In the overall advancing coordinate system, the difference between the set of discrete curve segments and the corresponding fitted ideal straight line is the space straightness error, which can be used as an evaluation index to measure the space straightness of the scraper conveyor.

[0129]

[0130] Where R l 0 is the corresponding point on the fitted ideal straight line of the discrete point set of the scraper conveyor in the coordinate system , p2 is the pose information of the point on the middle trough in the local reference coordinate system, and x is the parametric model of each middle trough in the local reference coordinate system. is the space straightness error, R j is the point on the discrete trajectory in the absolute coordinate system, and R0 is the coordinate in the absolute coordinate system .

[0131] In order to describe the overall space straightness characteristics of the scraper conveyor, the space straightness error density ρ of the scraper conveyor in the lateral advancing direction is introduced s . In the present invention, the rotating body with the discrete surface of the scraper conveyor as the symmetry plane is defined as the standard discrete body; the rotating body with the fitted ideal straight line as the axis and the discrete quasi-lines of each middle trough as the generatrices is defined as the error discrete body. The present invention defines the space straightness error density as the mass volume ratio of the error discrete body to the standard discrete body. The specific definition is shown in formula (8):

[0132]

[0133] The space straightness error density ρ of the scraper conveyor in the lateral advancing direction s reflects the average straightness error of the scraper conveyor and reflects the overall space straightness characteristics of the scraper conveyor. The smaller the value of ρ s , the better the space straightness of the scraper conveyor.

[0134] ② Spatial direction error model of the scraper conveyor along the overall advancing direction (longitudinal advancing) of the fully mechanized coal mining face

[0135] Under the discrete coal seam section S i , the discrete surface ∑S of the scraper conveyor tThe spatial straightness characteristic can be obtained from the content of step ①. However, when constructing its pose model, the characteristic in the advancing direction of the working face reflects the pitching characteristic of the scraper conveyor and the cutting undulation of the coal seam floor. This characteristic is called the direction characteristic of the middle trough. As Figure 4 shown in b of, the present invention uses a spherical curve to describe this characteristic, and the unit vector of any straight line represented by is transformed into the overall advancing coordinate system . The trajectory of the vector end points is located on the same spherical surface. In the fixed coordinate system, it is shown as:

[0136]

[0137] When the coal seam cutting floor is an ideal flat surface, the trajectory of the scraper conveyor along the advancing direction of the fully mechanized coal mining face always remains parallel, and the values of each middle trough are the same. However, in the actual mining process, the coal seam cutting floor is not flat after being affected by the undulation of the coal seam base and the cutting of the shearer. Therefore, is transformed into the overall advancing coordinate system , and the obtained spherical curve is a set of non-coincident discrete points. However, during the advancement of the scraper conveyor, there is a direction in which the radius of the enveloping sphere is the smallest. This direction is defined as the minimum error direction during longitudinal advancement. At this time, the spatial straightness of the scraper conveyor is least affected by the undulation of the cutting floor in the coal seam dip direction. According to this direction, the direction error model ΔS d of the entire scraper conveyor in the advancing direction of the fully mechanized coal mining face can be obtained as follows:

[0138]

[0139] where x is the least square dihedral angle parameter relative to the absolute reference coordinate system {o}, is the vector under the dihedral angle (δ1 (j) , δ2 (j) ) parameter corresponding to each middle trough, ΔS d is the direction error model of the entire scraper conveyor in the advancing direction of the fully mechanized coal mining face, and the minimum direction error model is ΔS d (x).

[0140] During the advancement of the fully mechanized coal mining face, it is desired to ensure the straightness of the scraper conveyor to make the mining process safe and efficient. Therefore, it is necessary to determine the overall direction error of the scraper conveyor. After establishing the direction error model for the discrete point set, it is necessary to determine the direction error density model ρ d of the scraper conveyor. ρ dDefined as the ratio of the mass of the spherical direction error to the area of the sphere, as shown in formula (11).

[0141]

[0142] ρ d is the straightness error density of the longitudinal advancement space of the scraper conveyor, reflecting the influence degree of the undulation of the coal seam floor on the pitching attitude of the scraper conveyor. The smaller the ρ d value, the smaller the influence of the undulation of the coal seam floor on the space straightness of the scraper conveyor.

[0143] Step 3: Establishment of the space straightness evaluation model for the hydraulic support group facing each discrete coal seam section

[0144] ⑴ Establishment of the geometric model of the hydraulic support group trajectory

[0145] As Figure 5 shown, under the absolute reference coordinate system {o; x; y; z} established at the intersection of the roadway and the working face, a local reference coordinate system family {o iH ; x iH ; y iH ; z iH} is established at the centroid position of each fully supported hydraulic support.

[0146] The geometric model of the trajectory of the hydraulic support group is a model for describing the pose of the scraper conveyor, and the spatial pose of the scraper conveyor is represented by discrete planes and lines. The coordinate system during the advancement process of the hydraulic support group is a three-level system, {O} is the absolute coordinate system, is the overall advancement coordinate system of the hydraulic support group, is the local reference coordinate system. The pose changes along the advancement direction of a single hydraulic support and along the cutting direction of the shearer are represented by vectors and respectively. The attitude angles of a single hydraulic support H j relative to the overall advancement coordinate system are (α j H , β j H , γ j H ), then the trajectory of a single hydraulic support H j relative to the overall advancement coordinate system is represented as Γ t (H) , and the formula is as follows:

[0147]

[0148] The coordinate trajectories of each hydraulic support relative to the overall advancement coordinate system are represented by indicates the local reference coordinate system relative to the overall advancing coordinate system the coordinates are is the local reference coordinate system relative to the overall advancing coordinate system the angular transformation matrix.

[0149] In the local reference coordinate system, it is also necessary to describe the attitude of each hydraulic support. The straight line passing through any point parallel to the center line of the hydraulic support base along the transverse advancing direction, and the dihedral angle in the direction of this straight line is (α j ' (H) , β j ' (H) ). The unit vector of this straight line in the local reference coordinate system is represented by p i .

[0150] p j (H) = [sinα j ' (H) cosβ j ' (H) , sinα j ' (H) sinβ j ' (H) , cosα j ' (H) T , (j = 1…n) (14)

[0151] In summary, the discrete trajectories of each hydraulic support in the overall advancing coordinate system form a discrete surface ∑S t H with Γ i (H) as the discrete directrix and p t H .

[0152]

[0153] where n is the number of discrete units of the hydraulic support, i.e., the number of middle troughs, and j is the jth hydraulic support.

[0154] ⑵ Establishment of the discrete spatial pose error model of the hydraulic support group

[0155] ① Spatial straightness error model of the hydraulic support group along the shearer walking direction (transverse advancement)

[0156] Similar to the spatial straightness requirement of the scraper conveyor, such as Figure 6As shown in a of , under the discrete coal seam section S1, the hydraulic support group needs to maintain its spatial straightness to meet the requirements during the advancement of the fully mechanized coal mining face, so as to ensure the spatial straightness of the scraper conveyor after the pushing action is executed. However, in actual situations, due to the undulations of the coal seam and the execution errors of the hydraulic cylinders, the trajectory of the hydraulic support group approximately presents the form of a spatial curve. Due to the gaps between adjacent hydraulic supports, the hydraulic support group also appears as a set of discrete curve segments that are not collinear in the spatial position.

[0157] In the overall advancement coordinate system, the difference between the set of discrete curve segments and the corresponding fitted ideal straight line is the spatial straightness error, which can be used as an evaluation index to measure the spatial straightness of the hydraulic support group.

[0158]

[0159] Where R l 0(H) is the corresponding point on the fitted ideal straight line of the discrete point set of the hydraulic support in the coordinate system , p2 H is the pose information of the point on the middle trough in the local reference coordinate system, x is the parametric model of each middle trough in the local reference coordinate system, is the spatial straightness error, R H j is the point on the discrete trajectory in the absolute coordinate system, R0 (H) is in the absolute coordinate system coordinates.

[0160] In order to describe the overall straightness characteristics of the hydraulic support group, the present invention introduces the spatial straightness error density ρ s H of the hydraulic support group. The present invention defines the rotating body with the discrete surface at the center of gravity position of a single hydraulic support as the symmetry plane as the standard discrete body of the hydraulic support; the rotating body with the ideal fitted straight line as the axis and the discrete directrix of each hydraulic support as the generatrix is the error discrete body of the hydraulic support. The present invention defines the spatial straightness error density as the mass volume ratio of the error discrete body of the hydraulic support to the standard discrete body of the hydraulic support. The specific definition is shown in formula (18):

[0161]

[0162] The spatial straightness error density ρ s H of the lateral advancement of the hydraulic support group reflects the average spatial straightness error of the hydraulic support group and also reflects the overall spatial straightness characteristics of the hydraulic support group. The smaller the value of ρ s H , the better the spatial straightness of the hydraulic support group.

[0163] ②Spatial Direction Error Model of Hydraulic Support Group along the Overall Advancement Direction (Longitudinal Advancement) of Fully Mechanized Coal Mining Face

[0164] As Figure 6 shown in b of [], when constructing the pose model of the hydraulic support group under the discrete coal seam section S1, the characteristics in the working face advancement direction reflect the pitching characteristics of the hydraulic support group and the cutting undulation of the coal seam floor. In this section, this characteristic is called the direction characteristic of the hydraulic support group. The present invention uses a spherical curve to describe this characteristic, and converts the unit vector of any straight line represented by to the overall advancement coordinate system . The trajectory of the vector end point is located on the same spherical surface, . In the fixed coordinate system, it is shown as: When the coal seam cutting floor is an ideal flat surface, the trajectories of the hydraulic supports along the advancement direction of the fully mechanized coal mining face always remain parallel, and the

[0165]

[0166] values of each hydraulic support are the same. However, in the actual mining process, the coal seam cutting floor is not flat due to the influence of the coal seam basement undulation and shearer cutting. Therefore, after converting to the overall advancement coordinate system of the hydraulic support group, the obtained spherical curve is a set of non-coincident discrete points. However, during the advancement of the hydraulic support group, there is a direction that makes the radius of the spherical curve the smallest. This direction is defined as the minimum error direction during the longitudinal advancement of the hydraulic support group. At this time, the straightness of the hydraulic support group is least affected by the cutting floor undulation in the coal seam dip direction. According to this direction, the direction error model ΔS of the entire hydraulic support group in the advancement direction of the fully mechanized coal mining face can be obtained as follows: d (H) As shown below:

[0167]

[0168] where x is the least square dihedral angle parameter relative to the absolute reference coordinate system {o}, is the vector under the dihedral angle (δ1 (j)H , δ2 (j)H ) parameter, ΔS d (H) is the direction error model of the entire hydraulic support group in the advancement direction of the fully mechanized coal mining face, and the minimum direction error model is ΔS d (H) (x).

[0169] During the advancement of the fully mechanized coal mining face, it is desired to ensure that the pitching and yawing advancement of the hydraulic support group meets the requirements, enabling the mining process to proceed safely and efficiently. Therefore, it is necessary to determine the overall direction error of the hydraulic support group. After establishing the direction error model for the hydraulic support, it is necessary to determine the direction error density model ρ of the hydraulic support group. d (H) ρ d (H) is defined as the ratio of the mass of the spherical direction error to the area of the sphere, as shown in formula (21).

[0170]

[0171] ρ d (H) represents the straightness error density of the longitudinal advancement space of the hydraulic support group, reflecting the influence degree of the undulation of the coal seam floor on the pitching and yawing postures of the hydraulic support group. The smaller the value of ρ d (H) , the smaller the influence of the undulation of the coal seam floor on the straightness of the space of the hydraulic support group.

[0172] Step 4: Establishment of the space straightness evaluation model for the fully mechanized coal mining face facing each discrete coal seam section

[0173] On the basis of completing the construction of the space straightness evaluation models for the scraper conveyor and the hydraulic support group, it is necessary to define the overall space straightness of the fully mechanized coal mining face in combination with the motion characteristics of the floating connection mechanism.

[0174] As Figure 7 shown, the analysis of the space straightness of the fully mechanized coal mining face under the discrete coal seam section S1:

[0175] The motion of the floating connection mechanism includes the elongation of the piston rod, the yawing motion and the pitching motion of the push rod, and the yawing motion of the connection head. On the basis of ensuring the space straightness of the hydraulic support and the scraper conveyor, the overall space straightness situation of the hydraulic support group and the scraper conveyor can be obtained according to the motion characteristics of the floating connection mechanism. Through the overall motion characteristics M<d i , θ2, θ3, θ4> evaluation, where d i represents the pushing amount of the piston rod in the floating connection mechanism, θ2 represents the pitching angle of the push rod, θ3 represents the yawing angle of the push rod, and θ4 represents the yawing angle of the connection head, as shown in formula (22).

[0176]

[0177] ρ FIt represents the consistency index of the pushing posture of the scraper conveyor and the floating connection mechanism of the hydraulic support group. The value of this index ranges between 0 and 1, reflecting the similarity of the trajectories of the hydraulic support group and the scraper conveyor in terms of spatial straightness. The larger this value is, the more consistent the spatial straightness of the hydraulic support group and the scraper conveyor is, indicating a higher degree of satisfaction with the overall spatial straightness of the hydraulic support group and the scraper conveyor.

[0178] When the advancing spatial straightness error density of the hydraulic support group and the scraper conveyor, and the consistency index of the pushing posture of the floating connection mechanism between the scraper conveyor and the hydraulic support group satisfy Equation (23), the spatial straightness requirements are met during the fully mechanized coal mining face mining.

[0179]

[0180] Step Five: Analysis of the Spatial Straightness of the Fully Mechanized Coal Mining Face Facing the Whole Coal Seam

[0181] After completing the analysis of the spatial straightness of the fully mechanized coal mining face in discrete coal seam sections, this step will analyze the spatial straightness of the fully mechanized coal mining face under the conditions of the entire coal seam, and splice and analyze the advancing spatial straightness error density of the hydraulic support group and the scraper conveyor corresponding to each discrete coal seam body, as well as the consistency index of the pushing posture of the floating connection mechanism between the scraper conveyor and the hydraulic support group. As Figure 8 shown, taking the coal seam section spliced from discrete coal seam sections S2 and S3 as an example for analysis. On the basis that the spatial straightness of the fully mechanized coal mining face corresponding to each discrete coal seam body is satisfied, m middle troughs and the corresponding hydraulic supports are respectively selected from both sides of the coal seam peak bottom point to analyze the overall spatial straightness of the fully mechanized coal mining face. Among them, the coal seam peak bottom point satisfies Equation (24):

[0182]

[0183] Three middle troughs and the corresponding hydraulic supports are respectively selected from both sides of the coal seam peak bottom point of the coal seam section spliced from discrete coal seam sections S2 and S3. Using Equations (8), (11), (18), (21), and (22), the lateral advancing spatial straightness error density ρ s of the scraper conveyor, the longitudinal advancing spatial straightness error density ρ d of the scraper conveyor, the lateral advancing spatial straightness error density ρ s H of the hydraulic support group, the longitudinal advancing spatial straightness error density ρ d (H) of the hydraulic support group, and the consistency index ρ F of the pushing posture of the floating connection mechanism between the scraper conveyor and the hydraulic support group are obtained respectively, as shown in Equation (25).

[0184]

[0185] Judge the spatial straightness accuracy of the fully mechanized coal mining face at the peak bottom point according to the calculation results. If during the mining process, the key parameter values of the straightness of the trajectories of the scraper conveyor and the hydraulic support group at the coal seam peak bottom junction meet the formula (26), then the fully mechanized coal mining face meets the spatial straightness requirements.

[0186]

[0187] Among them, the key parameter values of spatial straightness include the lateral advancement spatial straightness error density ρ of the scraper conveyor s 、the lateral advancement spatial straightness error density ρ of the hydraulic support group s H 、the longitudinal advancement spatial straightness error density ρ of the scraper conveyor d 、the longitudinal advancement spatial straightness error density ρ of the hydraulic support group d (H) 、the pushing pose consistency index ρ of the floating connection mechanism between the scraper conveyor and the hydraulic support group F 、and the pushing pose consistency index ρ of the floating connection mechanism between the scraper conveyor and the hydraulic support group F .

[0188] Then for the entire coal seam the spatial straightness requirements of the fully mechanized coal mining face are as shown in formula (27):

[0189]

[0190] Among them, represents the discrete coal seam section at the coal seam peak bottom junction, represents the discrete coal seam section without considering the coal seam peak bottom junction, and s represents the coal seam section where it is located.

Claims

1. An evaluation method for the spatial straightness of a fully-mechanized mining face under complex coal seam conditions, characterized in that, Including: Step 1: Detect the undulation of the coal seam at the initial stage of the fully mechanized coal mining face. According to the detected undulation of the coal seam determined by the detection data, segment the coal seam. Step 2: Establish a spatial straightness evaluation model for the scraper conveyor facing each discrete coal seam segment, including: (1) Establish a geometric model of the scraper conveyor trajectory and (2) establish a discrete spatial pose error model of the scraper conveyor. Among them, the discrete spatial pose error model of the scraper conveyor includes: ① Spatial straightness error model of scraper conveyor along the traveling direction of shearer, and the density ρ of the lateral propulsion spatial straightness error of the scraper conveyor is obtained by this model s , and ② the spatial direction error model of the scraper conveyor along the overall advancing direction of the fully mechanized coal face, and this model obtains the straightness error density ρ of the longitudinal advancing space of the scraper conveyor d ; Step 3: Establish a spatial straightness evaluation model for the hydraulic support group facing each discrete coal seam segment, including: (1) Establish a geometric model of the hydraulic support group trajectory and (2) establish a discrete spatial pose error model of the hydraulic support group. Among them, the discrete spatial pose error model of the hydraulic support group includes: ①The spatial straightness error model of the hydraulic support group along the traveling direction of the shearer, which obtains the density ρ of the spatial straightness error of the lateral advancement of the hydraulic support group s H , and ② the spatial direction error model of the hydraulic support group along the overall advancing direction of the fully mechanized coal mining face, which obtains the straightness error density ρ of the longitudinal advancing space of the hydraulic support group d (H) ; Step 4: Establish a spatial straightness evaluation model for the fully mechanized coal mining face facing each discrete coal seam segment. Based on the construction of the spatial straightness evaluation models for scraper conveyors and hydraulic support groups, the overall spatial straightness of the fully mechanized coal mining face is defined by combining the motion characteristics of the floating connection mechanism; when the spatial straightness error density of the advancing space of the hydraulic support group and the scraper conveyor, and the displacement pose consistency index ρ of the floating connection mechanism between the scraper conveyor and the hydraulic support group F meet the formula (23), the fully mechanized coal mining face meets the requirements of spatial straightness during mining; Step 5: Analyze the spatial straightness of the fully mechanized coal mining face for the whole coal seam. The straightness error density of the advancing space of the hydraulic support groups corresponding to each discrete coal seam body, the scraper conveyor, and the consistency index of the pushing pose of the floating connection mechanism between the scraper conveyor and the hydraulic support groups are spliced and analyzed, and finally the space straightness requirement of the fully-mechanized coal mining face for the entire coal seam is obtained is as shown in formula (27): Among them, represents the discrete coal seam section at the intersection of the peak and bottom of the coal seam, represents the discrete coal seam section without considering the intersection of the peak and bottom of the coal seam, and s represents the coal seam section where it is located.

2. The evaluation method for the spatial straightness of the fully mechanized coal mining face under complex coal seam conditions according to claim 1, characterized in that: In Step 1, process the detection data through interpolation and prediction to obtain the coal seam trajectory curve F(x, y, z) = 0 in the specified coordinate system o-xyz; the method for segmenting the coal seam segment is: along the x-axis direction, use the peak-bottom point of the coal seam curve as the segmentation point for segmentation. Analyze the attitude of the scraper conveyor on the segmented coal seam segment by analyzing the partial derivative of the coal seam trajectory curve and taking the partial derivative in the x direction; the coal seam segmentation principle is shown in the formula: ∑ represents the coal seam surface, x represents the serial number of the coal seam points collected along the coal seam strike, y represents the overall advancement of the fully mechanized coal mining face along the coal seam dip direction, and z represents the height of the coal seam in the specified coordinate system o-xyz.

3. The evaluation method for the spatial straightness of the fully-mechanized mining face under complex coal seam conditions according to claim 2, wherein: In Step 2, the method for establishing the geometric model of the scraper conveyor trajectory is: An absolute reference coordinate system {O(x, y, z)} is established at the junction of the roadway and the fully mechanized coal mining face, and a family of local reference coordinate systems is established on each middle trough section. The coordinate system for the advancing process of the scraper conveyor is a three-level system, {O} is the absolute coordinate system, which is the overall advancing coordinate system, and is the local reference coordinate system. k is the number of advancing times, and i is the serial number of the middle trough. Along the middle trough A of the scraper conveyor i The pose changes in the advancing direction and along the cutting direction of the shearer are respectively represented by the vectors and . The attitude angles of the middle trough relative to the overall advancing coordinate system are (α j , β j , γ j ). Then the discrete trajectory of the middle trough A of the scraper conveyor j relative to the overall advancing coordinate system is represented as Γ t , and the formula is as follows: The coordinate trajectories of each middle trough relative to the overall propulsion coordinate system are represented by R i The local reference coordinate system relative to the overall propulsion coordinate system has coordinates [R 0j is the local reference coordinate system relative to the overall propulsion coordinate system is the angular transformation matrix; In the local reference coordinate system, a straight line passing through an arbitrary point parallel to the axis of the middle groove in the transverse advancement direction, and the dihedral angle in the direction of this straight line is (α j ′, β j ′), and the unit vector of this straight line in the local reference coordinate system is represented by p j ; p j = [sinα j ′ cosβ j ′, sinα j ′ sinβ j ′, cosα j ′] T , j = 1…n (4) In summary, the discrete trajectories of each middle trough in the overall propulsion coordinate system form a discrete surface ∑ t with Γ i as the discrete directrix and p St as the generatrix; Where n is the number of discrete units of the scraper conveyor, that is, the number of middle troughs, and j is the jth middle trough.

4. The evaluation method for the spatial straightness of the fully mechanized coal mining face under complex coal seam conditions according to claim 3, characterized in that: In Step 2, the method for establishing the spatial straightness error model of the scraper conveyor along the walking direction of the shearer is: In the overall advancement coordinate system, the difference between the discrete curve segment set and the corresponding fitted ideal straight line is the spatial straightness error, which is used as an evaluation index for measuring the spatial straightness of the scraper conveyor. where R l 0 is the point corresponding to the discrete point set of the scraper conveyor on the fitted ideal straight line in the coordinate system , p2 is the pose information of the point on the middle trough in the local reference coordinate system, and x is the parametric model of each middle trough in the local reference coordinate system is the spatial straightness error, and R j is the point on the discrete trajectory in the absolute coordinate system, and R0 is the coordinate in the absolute coordinate system ; Define the rotating body with the discrete surface of the scraper conveyor as the symmetry plane as the standard discrete body; the rotating body with the axis of the fitted ideal straight line and the discrete reference lines of each middle trough as the generatrix as the error discrete body; define the straightness error density ρ of the transverse propulsion space of the scraper conveyor s as the mass volume ratio of the error discrete body to the standard discrete body, and the specific definition is shown in formula (8): The straightness error density ρ of the transverse propulsion space of the scraper conveyor s reflects the average space straightness error of the scraper conveyor, ρ s The smaller the value, the better the space straightness of the scraper conveyor.

5. The evaluation method for the spatial straightness of the fully mechanized coal mining face under complex coal seam conditions according to claim 4, characterized in that: In Step 2, the method for establishing the spatial direction error model of the scraper conveyor along the overall advancement direction of the fully mechanized coal mining face is: Described by a spherical curve, the unit vector of any straight line represented by is transformed to the overall propulsion coordinate system Under this condition, the trajectories of the vector endpoints are all located on the same spherical surface, which is manifested in the fixed coordinate system as: During the advancement of the scraper conveyor, there is a direction in which the radius of the envelope sphere is minimized. This direction is defined as the minimum error direction during longitudinal advancement. At this time, the spatial straightness of the scraper conveyor is least affected by the undulation of the cut floor in the direction along the coal seam dip. Based on this direction, the direction error model ΔS of the entire scraper conveyor in the advancement direction of the fully mechanized coal mining face is obtained d As follows: Where x is relative to the absolute reference coordinate system {o; x; y; The least dihedral angle parameter of z}, is the vector under the dihedral angle (δ1 (j) , δ2 (j) ) parameter corresponding to the middle slot of each section, and ΔS d is the direction error model of the entire scraper conveyor in the advancing direction of the fully mechanized coal mining face. The minimum direction error model is ΔS d (x); After establishing the direction error model ΔS for the discrete point set d the linearity error density ρ of the longitudinal advancement space of the scraper conveyor is determined d , ρ d is defined as the ratio of the mass of the spherical direction error to the area of the sphere, as shown in formula (11). Longitudinal straightness error density ρ of scraper conveyor in the advancing direction d reflects the influence degree of the undulation of coal seam floor on the pitching attitude of the scraper conveyor. The smaller the value of ρ d is, the smaller the influence of the undulation of coal seam floor on the spatial straightness of the scraper conveyor is.

6. The evaluation method for the spatial straightness of the fully mechanized coal mining face under complex coal seam conditions according to claim 5, characterized in that: In Step 3, the method for establishing the geometric model of the hydraulic support group is: Under the absolute reference coordinate system {o; x; y; z} established at the intersection of the roadway and the working face, a family of local reference coordinate systems {o iH ; x iH ; y iH ; z iH} is established at the center-of-gravity position when each hydraulic support is fully supported; The coordinate system for the advancement process of a hydraulic support group is a three - level system, where {O} is the absolute coordinate system, which is the overall advancement coordinate system of the hydraulic support group, and which is the local reference coordinate system; the pose changes along the advancement direction of a single hydraulic support and along the cutting direction of the shearer are represented by vectors and respectively. The attitude angle of a single hydraulic support H j relative to the overall advancement coordinate system is Then the discrete trajectory of a single hydraulic support H j relative to the overall advancement coordinate system is represented as Γ t (H) , and the formula is as follows: The coordinate trajectories of each hydraulic support relative to the overall advancing coordinate system are represented by denote the local reference coordinate system relative to the overall advancing coordinate system The coordinates are is the local reference coordinate system relative to the overall advancing coordinate system is the angular transformation matrix; In the local reference coordinate system, it is also necessary to describe the attitude of each hydraulic support. A straight line passing through an arbitrary point parallel to the center line of the base of the hydraulic support along the transverse advancing direction, and the dihedral angle in the direction of this straight line is (α j '(H) , β j ′(H) ). The unit vector of this straight line in the local reference coordinate system is represented by p i . p j (H) = [sinα j ′ (H) cosβ j ′ (H) , sinα j ′ (H) sinβ j ′ (H) , cosα j ′ (H) T , j = 1…n (14)​ In summary, the discrete trajectories of each hydraulic support in the overall propulsion coordinate system form a discrete surface ∑S t H with Γ j (H) as the discrete directrix and p t H as the generatrix. Where n is the number of discrete units of the hydraulic support, that is, the number of middle troughs, and j is the jth hydraulic support.

7. The evaluation method for the spatial straightness of the fully mechanized coal mining face under complex coal seam conditions according to claim 6, characterized in that: In Step 3, the method for establishing the spatial straightness error model of the hydraulic support group along the traveling direction of the shearer is as follows: In the overall advancing coordinate system, the difference between the discrete curve segment set and the corresponding fitted ideal straight line is the spatial straightness error, which can be used as an evaluation index for measuring the spatial straightness of the hydraulic support group; where R l 0(H) is the point corresponding to the fitted ideal straight line of the discrete point set of the hydraulic support in the coordinate system below, p2 H is the pose information of the point on the middle trough in the local reference coordinate system, x is the parametric model of each middle trough in the local reference coordinate system, is the spatial straightness error, R H j is the point on the discrete trajectory in the absolute coordinate system, R0 (H) is in the absolute coordinate system coordinates; Define the rotating body with the discrete surface at the center of gravity position of a single hydraulic support as the symmetry plane as the standard discrete body of the hydraulic support; the rotating body with the ideal fitting straight line as the axis and the discrete quasi-line of each hydraulic support as the generatrix as the error discrete body of the hydraulic support; define the straightness error density ρ of the lateral propulsion space of the hydraulic support group s H as the mass-volume ratio of the error discrete body of the hydraulic support to the standard discrete body of the hydraulic support, and the specific definition is shown in formula (18): The linearity error density ρ of the lateral advancement space of a group of hydraulic supports s H reflects the average linearity error of the group of hydraulic supports and also reflects the overall linearity characteristics of the group of hydraulic supports; ρ s H The smaller the value, the better the linearity of the group of hydraulic supports.

8. The evaluation method for the spatial straightness of the fully mechanized coal mining face under complex coal seam conditions according to claim 7, wherein: In Step 3, the method for establishing the spatial direction error model of the hydraulic support group along the overall advancing direction of the fully mechanized coal mining face is as follows: Described by spherical curves, the unit vector of any straight line represented by is transformed to the overall propulsion coordinate system where the trajectory of the vector end point lies on the same spherical surface, which appears in the fixed coordinate system as: During the advancement of a group of hydraulic supports, there is a direction in which the radius of the spherical curve is minimized. This direction is defined as the minimum error direction when the group of hydraulic supports advances longitudinally. At this time, the spatial straightness of the group of hydraulic supports is least affected by the undulation of the cut floor in the direction along the coal seam dip. Based on this direction, the direction error model ΔS of the entire group of hydraulic supports in the advancing direction of the fully mechanized coal mining face is obtained. d (H) As shown below: where x is relative to the absolute reference coordinate system {o; x; y; The least dihedral angle parameter of z is the vector under the dihedral angle (δ1 (j)H , δ2 (j)H ) parameter, and ΔS d (H) is the direction error model of the entire hydraulic support group in the advancing direction of the fully mechanized coal mining face. The least direction error model is ΔS d (H) (x); After establishing the direction error model ΔS for the hydraulic support d (H) the linearity error density ρ of the longitudinal propulsion space of the hydraulic support group is determined d (H) , ρ d (H) is defined as the ratio of the mass of the spherical direction error to the area of the sphere, as shown in formula (21). Longitudinal straightness error density ρ of a group of hydraulic supports d (H) reflects the influence degree of the undulation of coal seam floor on the pitching attitude of a group of hydraulic supports. The smaller the value of ρ d (H) , the smaller the influence of the undulation of coal seam floor on the spatial straightness of a group of hydraulic supports.

9. The evaluation method for the spatial straightness of the fully mechanized coal mining face under complex coal seam conditions according to claim 8, wherein: In step 4, the movement of the floating connection mechanism includes the elongation of the piston rod, the yaw movement and the pitch movement of the push rod, and the yaw movement of the connection head. On the basis of ensuring the spatial straightness of the hydraulic support and the scraper conveyor, the overall spatial straightness of the hydraulic support group and the scraper conveyor is obtained according to the movement characteristics of the floating connection mechanism. The overall movement characteristics M<d i , θ2, θ3, θ4> of the floating connection mechanism are evaluated, where d i represents the pushing amount of the piston rod in the floating connection mechanism, θ2 represents the pitch angle of the push rod, θ3 represents the yaw angle of the push rod, and θ4 represents the yaw angle of the connection head, as shown in formula (22). ρ F represents the consistency index of the pushing pose of the scraper conveyor and the floating connection mechanism of the hydraulic support group. The value of this index ranges between 0 and 1, reflecting the similarity of the trajectories of the hydraulic support group and the scraper conveyor in terms of spatial straightness. ρ F The larger the value of ρ, the more consistent the spatial straightness of the hydraulic support group and the scraper conveyor, indicating a higher degree of satisfaction with the overall spatial straightness of the hydraulic support group and the scraper conveyor.

10. The evaluation method for the spatial straightness of the fully mechanized coal mining face under complex coal seam conditions according to claim 9, wherein: In Step 5, on the basis that the spatial straightness of the fully mechanized coal mining face corresponding to each discrete coal seam body is satisfied, m middle troughs and the corresponding hydraulic supports are respectively selected from both sides of the peak bottom point of the coal seam to analyze the overall spatial straightness of the fully mechanized coal mining face, and the peak bottom point satisfies formula (24): Select m middle troughs and their corresponding hydraulic supports on both sides from the bottom point of the coal seam peak, and use formulas (8), (11), (18), (21), and (22) to obtain the straightness error density ρ of the transverse propulsion space at the splicing point of the two discrete coal seam segments at the bottom point of the coal seam peak s , the straightness error density ρ of the longitudinal propulsion space of the scraper conveyor d , the straightness error density ρ of the transverse propulsion space of the hydraulic support group s H , the straightness error density ρ of the longitudinal propulsion space of the hydraulic support group d (H) , the consistency index ρ of the pushing pose of the floating connection mechanism between the scraper conveyor and the hydraulic support group F , as shown in formula (25). The value of m is determined according to the number of equipment a laid in the discrete coal seam section and the number of middle troughs b involved when the shearer cuts triangular coal, m = max(a, b); Judge the spatial straightness accuracy of the fully mechanized coal mining face at the peak bottom point according to the calculation result. If the key parameter value of the straightness of the trajectory of the scraper conveyor and the hydraulic support group of the coal seam after the peak and bottom of the coal seam are spliced during the mining process meets the formula (26), then the fully mechanized mining face meets the spatial straightness requirements.

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