A coal mining face advance control method

Abstract

This invention provides a method for controlling a coal mining advance face, characterized by comprising multiple driven coal mining advance faces connected by multiple drive units, wherein N coal mining advance faces form an advance group (N is an integer greater than 1), the advance group includes a millimeter-wave radar and / or a lidar, the multiple coal mining advance faces form M advance groups (M is an integer greater than or equal to 2), all adjacent advance groups of the M advance groups include at least one identical coal mining advance face, the millimeter-wave radar and / or lidar in each advance group generates control signals to control each advance face in the advance group, and by setting an overlapping scheme, the multiple coal mining advance faces can have a unified reference, thereby enabling the control signals generated by the millimeter-wave radar and / or lidar to adjust the multiple coal mining advance faces to work efficiently in an overall mode.

Description

Technical Field

[0001] This invention relates to the field of coal mining face control technology, and more specifically, to a coal mining face control scheme using radar. Background Technology

[0002] Key production equipment in a fully mechanized coal mining face includes: scraper conveyors, coal mining machines, and hydraulic supports. The coal mining machine moves along the chute of the scraper conveyor, cutting coal off the coal face. The scraper conveyor transports the falling coal out of the mining face and provides a track for the coal mining machine's movement. Hydraulic supports provide support for the working face and move the scraper conveyor. Specifically, the mining face consists of multiple hydraulic supports arranged sequentially on the face to support the roof and facilitate the movement of the scraper conveyor.

[0003] Typically, during operation, multiple hydraulic supports on the working face need to be roughly on the same plane to ensure normal operation of the working face. In coal mining, the scraper conveyor serves as the track for the coal mining machine; therefore, the straightness of the hydraulic supports on the working face is a prerequisite for ensuring the straightness of the scraper conveyor, ultimately enabling the coal mining machine on it to achieve good coal cutting results.

[0004] With the development of the mining industry, new requirements have been placed on automated and intelligent mining, necessitating that coal mining machines, hydraulic supports, and scraper conveyors can work and move automatically and collaboratively. However, due to the complex ground conditions and significant vibrations in the working environment, the advancing faces of hydraulic supports are not on the same plane, or the advancing faces have a certain angle (not 90 degrees perpendicular) relative to the ground. In existing technologies, workers at the coal mining site usually determine whether the hydraulic supports on the working face are on the same plane. If they are not determined to be on the same plane, workers manually adjust the hydraulic supports, resulting in low efficiency in adjusting the hydraulic supports.

[0005] Therefore, how to quickly and conveniently obtain the real-time status of multiple advancing faces, and achieve precise control over the tilt angle of each advancing face and the integrated working mode guaranteed by each face as a whole, is essential for efficient and continuous automated operation of coal mining, and is also an urgent problem to be solved in the coal mining process. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art by providing a method for controlling the coal mining face, thereby solving the technical problems in related technologies where manual adjustment of the face and inaccurate visual observation seriously hinder the efficiency improvement of the coal mining propulsion system throughout the entire coal mining process.

[0007] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0008] This invention provides a semiconductor laser emitter, characterized in that it comprises:

[0009] Multiple driven coal mining faces are connected by multiple drive units, wherein N coal mining faces form a propulsion group (N is an integer greater than 1), and the propulsion group includes a millimeter-wave radar and / or a lidar. The multiple coal mining faces form M propulsion groups (M is an integer greater than or equal to 2). All adjacent propulsion groups of the M propulsion groups include at least one identical coal mining face. The millimeter-wave radar and / or lidar in each propulsion group generates control signals to control each propulsion face in the propulsion group.

[0010] Optionally, the drive unit can linearly adjust the position of the coal mining face and also adjust the inclination angle of the coal mining face.

[0011] Optionally, the millimeter-wave radar and / or lidar within the propulsion group are configured with distance measurement accuracy based on the first distance deviation.

[0012] Optionally, the first distance deviation is a threshold value of the maximum distance deviation among the plurality of coal mining faces.

[0013] Optionally, the millimeter-wave radar and / or lidar in the propulsion group shall, at least in one of the following ways, adjust the distance deviation between two of the plurality of coal mining faces to not exceed the threshold of the distance deviation, such as power-on calibration, fixed time, fixed function relationship determination time, or adaptive adjustment, etc.

[0014] Optionally, the millimeter-wave radar and / or lidar within the propulsion group includes k ranging waves (k being an integer greater than or equal to 2) fed to the same propulsion surface, and the k ranging waves obtain the tilt angle of the propulsion surface through k sets of distances.

[0015] Optionally, each pair of adjacent ranging waves emitted from the k ranging waves has the same included angle.

[0016] Optionally, the parameters for determining the included angle of the ranging wave include at least the ranging accuracy of the millimeter-wave radar and / or lidar within the propulsion group.

[0017] Optionally, the inclination angle of the propulsion surface does not exceed the included angle threshold.

[0018] Optionally, the millimeter-wave radar and / or lidar in the propulsion group shall, at least in one of the following ways, adjust the tilt angle of each of the plurality of coal mining faces to not exceed the included angle threshold, such as power-on calibration, fixed time, fixed function relationship determination time, or adaptive adjustment, etc.

[0019] The beneficial effects of this invention are as follows: A method for controlling a coal mining advance face, characterized in that it comprises multiple driven coal mining advance faces connected by multiple drive units, wherein N coal mining advance faces form an advance group (N is an integer greater than 1), the advance group includes a millimeter-wave radar and / or a lidar, the multiple coal mining advance faces form M advance groups (M is an integer greater than or equal to 2), all adjacent advance groups of the M advance groups include at least one identical coal mining advance face, the millimeter-wave radar and / or lidar in each advance group generates control signals to control each advance face in the advance group, thus, by forming multiple advance faces into advance face groups with overlapping advance faces, multiple groups can be integrated into a whole, and it saves costs and avoids the technical problem of incoordination when multiple radars are working, without each advance face corresponding to a radar control module. At the same time, it also allows for individual adjustment of a single advance face, ensuring the high efficiency of the entire system. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of a propulsion system provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of a two-propulsion group radar layout provided in an embodiment of the present invention;

[0023] Figure 3 This invention provides a schematic diagram of a propulsion group in which the propulsion surfaces are symmetrically arranged along both sides of the radar.

[0024] Figure 4 This is a schematic diagram of the deviation between two propulsion surfaces provided in an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of a propulsion plate before a propulsion system advances a certain distance, provided in an embodiment of the present invention.

[0026] Figure 6 This is a schematic diagram of a propulsion plate after a propulsion system has advanced a certain distance, provided as an embodiment of the present invention.

[0027] Figure 7 This is a schematic diagram illustrating the distance deviation of the same propulsion plate before and after advancing a certain distance, provided by an embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram of a propulsion surface tilt angle structure provided in an embodiment of the present invention;

[0029] Figure 9 A schematic diagram of the tilt angle of the propulsion surface under different states is provided for an embodiment of the present invention;

[0030] Figure 10 This is a schematic diagram of different inclination angles of the propulsion surface in a propulsion group, provided as an embodiment of the present invention;

[0031] Figure 11 This is a schematic diagram of the measurement results of the inclination angle of the propulsion surface of a propulsion group provided in an embodiment of the present invention;

[0032] Figure 12 This is a schematic diagram of the transmitted and returned waves when the radar is a millimeter-wave radar, as provided in an embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0034] Figure 1 This is a schematic diagram of a propulsion system provided in an embodiment of the present invention. A radar 101 is provided every few propulsion rods 102, that is, a radar 101 for ranging is provided on the propulsion rod 102 of the hydraulic support, such as a lidar and / or millimeter-wave radar. At the same time, a corner reflector 103 is provided on the side of each propulsion plate facing the radar. In order to avoid the influence of vibration, the radar 102 can be mounted on an independent vibration-damping platform. Furthermore, the radar 102 should operate in a low frequency range as much as possible. Preferably, the radar frequency is 15 GHz, so as to prevent the influence of high humidity and high dust underground on the lidar ranging.

[0035] Furthermore, there are overlapping propulsion surfaces between the two radars 101, i.e., propulsion surfaces that repeatedly measure distances, so that the position of the two radars is measured through the same propulsion surface. In actual use, multiple coal mining propulsion surfaces may not be on the same plane, and the entire propulsion surface of the propulsion group or a certain propulsion surface has a certain angle relative to the ground. As a result, the coal mining machine, hydraulic support scraper conveyor, etc., cannot achieve coordinated propulsion, thus affecting the progress of coal mining work and making it difficult to continue the entire coal mining operation. In order to solve this problem, the multiple propulsion surfaces of the present invention establish a correspondence with the radar 101 in a certain way, so that the multiple propulsion surfaces form a whole, thereby ensuring that all propulsion surfaces as a whole can achieve efficient coal mining effect through automatic or manual adjustment.

[0036] Figure 2 This is a schematic diagram of a two-propulsion radar layout provided in an embodiment of the present invention. Figure 2 The number of propulsion surfaces N in each propulsion group is 6. Of course, in actual use, it is not limited to 6 propulsion surfaces; it can also be 5, 7, 8, etc. Figure 2 The diagram illustrates the layout of two propulsion groups and two radars. In this embodiment, propulsion group 1 corresponds to radar 1 and includes 1-6 (6 propulsion surfaces in total), and propulsion group 2 corresponds to radar 2 and includes 6-11 (6 propulsion surfaces in total). By setting at least one common propulsion surface 6 in the two propulsion groups, the connection between propulsion group 1 and propulsion group 2 is established. This also solves the problem that it is not possible to use only one radar to cover all propulsion surfaces in a short range. The technical effect of linking multiple propulsion groups of the entire system into a whole can be achieved by using low-cost radars. Of course, the number of common propulsion surfaces can be more than one, which is not limited here. Each propulsion group can also be composed of different numbers of propulsion surfaces to adapt to different working conditions. In this embodiment, the six propulsion surfaces of one propulsion group are symmetrically distributed along both sides of the radar.

[0037] Figure 3 This is a schematic diagram of a propulsion group in which the propulsion surfaces are symmetrically arranged on both sides of the radar, provided by an embodiment of the present invention. Of course, in actual use, the propulsion surfaces distributed on both sides of the radar can also be asymmetrically distributed. In the figure, the total width of the six propulsion surfaces of a propulsion group is L, and the vertical distance from the radar to the propulsion group is d. The angle between the line connecting the symmetrically distributed propulsion surfaces 1 and 6 to the radar and the propulsion plane is equal. The following will take two symmetrically distributed propulsion surfaces as an example to illustrate the method of obtaining the deviation between the two propulsion surfaces.

[0038] Figure 4 This is a schematic diagram of the deviation between two propulsion surfaces provided in an embodiment of the present invention. The distance deviation between the two propulsion surfaces is Δd. In order to meet the set threshold deviation, that is, at least the maximum distance deviation between the two propulsion surfaces in each propulsion group needs to not exceed the set deviation threshold, for example, the deviation threshold can be required to be 2cm. At this time, the accuracy of the radar can be determined in the following way, thereby associating the accuracy of the radar with the deviation requirement of the propulsion, and ensuring the accuracy of the control method. The relationship between distance deviation and radar ranging accuracy can be established from the diagram: d1 = D1sinθ1; d2 = D2sinθ2; where D1 is the distance between one of the two symmetrically placed propulsion surfaces obtained by the radar and the other of the two symmetrically placed propulsion surfaces obtained by radar 1, and θ1 and θ2 are the angles between the line connecting the propulsion surface and the radar and the propulsion surface, respectively. Therefore, Δd = D1sinθ1 - D2sinθ2. For two propulsion surfaces placed symmetrically on both sides of the radar, then θ1 = θ2. Thus, the above formula simplifies to Δd = sinθ1(D1 - D2) = sinθ1ΔD, where ΔD is the radar ranging accuracy. Figure 3 To further illustrate, we can obtain the following from the symmetrically distributed propagation surfaces 1 and 6: Therefore, we can obtain Where L and d are related to the system equipment, for example, the width of each propulsion surface is 1.75m, so the width L of each propulsion group is 1.75m * 6 = 10.5m. Generally, the value of d is in the range of 0.5-2.0m. Here, we take d as 2m as an example. At this time, we can obtain α≈70°, so θ=90°-70°=20°. From this, we can obtain the radar ranging accuracy ΔD related to the range deviation threshold. The above calculation is only an illustrative example, and the specific values ​​are not limited. The main purpose is to set a correlation between the radar's ranging accuracy and the distance deviation threshold.

[0039] Figure 5 This is a schematic diagram of a propulsion plate before a propulsion system advances a certain distance, provided in an embodiment of the present invention. It can also be a schematic diagram of the initial state or the state after installation. In this embodiment, four radars and corresponding propulsion groups are included. Propulsion groups 1 and 2 are arranged with at least one common propulsion surface, and propulsion groups 3 and 4 are arranged in a similar manner. However, propulsion groups 2 and 3 do not share a common propulsion group. In actual use, this is not limited to this method; every two adjacent propulsion groups can share a common propulsion surface, and the total number of propulsion groups is not limited to four. The distance deviation between any two propulsion groups within each propulsion group can be calculated using the previously described method and manually or automatically controlled to meet the distance deviation threshold. This ensures that each propulsion group has a planar state in the initial conditions of all propulsion groups in the initial state. Thus, the initial distances d1, d2, d3, and d4 between the radars and the propulsion surface in different propulsion groups are obtained. After the propulsion group advances a certain distance, the distance between each radar and the propulsion surface is obtained as follows: Figure 6 As shown, d1', d2', d3', and d4', etc., can be obtained by comparing the distances between the radar and the propulsion surface of different propulsion groups before and after advancing a certain distance. Figure 7 The distance deviation results shown are achieved by controlling the distance difference between two consecutive times within a certain threshold range to control the distance deviation during the propulsion process. Of course, the above is a scheme that uses multiple propulsion groups to form a unified whole and then controls the distance deviation after the propulsion surface has been working for a certain period of time. It can be set to check the deviation threshold after a fixed time (i.e., propulsion a fixed distance, etc.), or the deviation check and correction time can be determined according to a predetermined function relationship or table relationship, etc. It can also adaptively arrange the distance deviation check and correction time during the operation. It is not limited here, nor is it limited to using the method illustrated above to obtain the distance deviation. The deviation between every two panels can be obtained through a single panel distance deviation as described above. It is not limited here either.

[0040] During the advancement process, due to the complex ground conditions and significant vibrations in the working environment, the advancement surfaces of the hydraulic support are not on the same plane, or the advancement surfaces are at a certain angle relative to the ground. Figure 8 and Figure 9 A schematic diagram showing the inclined state of the propulsion surface, combined with... Figure 8 To illustrate the present invention's method for obtaining the propulsion surface tilt angle, the millimeter-wave radar and / or lidar within the propulsion group contains k ranging waves (k being an integer greater than or equal to 2) sent to the same propulsion surface. These are described here as threads; for example, this embodiment uses a 4-thread radar. This four-thread radar can simultaneously send ranging waves to four different points on the same propulsion plate. The angle of each ranging wave is fixed. After obtaining the distances between the radar and the four points on the propulsion plate, it then measures the distances to adjacent propulsion plates, thereby obtaining the distance between the radar and the propulsion plate. The angle between any two adjacent ranging waves is α. Therefore, from... Figure 8 We can obtain: The resolution of the ranging radar is ΔD, which can be represented as the maximum value of the radar coverage area in the diagram; therefore, its value is D. 最长测距波 -D 最短测距波 It can be approximated as Figure 8 Since d is the seed, ΔD = Htanβ. Using the two equations, we can obtain: This invention links the angle of the ranging wave with the ranging accuracy of the radar. Specifically, the parameter for determining the angle of the ranging wave includes at least the ranging accuracy of the millimeter-wave radar and / or lidar within the propulsion group. This clarifies the design of the ranging radar and also allows for the determination of the tilt angle of the propulsion surface. Of course, in practical applications, there are requirements for the tilt angle of the propulsion surface, such as not exceeding 5°. However, this is not the only possible value; further settings can be made in practical applications. Specifically, the tilt angle of the propulsion surface needs to meet a certain threshold requirement. When this value is exceeded, the propulsion surface can be manually or automatically adjusted to ensure that the tilt angle parameter is qualified. This method allows for the determination of the tilt angle of each propulsion surface to ensure that the tilt angle of each propulsion surface meets the set threshold. Another tilt angle verification scheme will be introduced below.

[0041] Similar to the previously described propulsion surface distance deviation detection scheme, such as Figure 10 As shown, the propulsion surfaces within each propulsion group tilt in the same direction. Therefore, it is assumed that the propulsion surfaces of one of the multiple propulsion groups are affected equally during operation, and thus the entire propulsion surface has the same tilt angle. Figure 10 In the system, if there are multiple propulsion surface groups corresponding to multiple radars, the tilt angle of each propulsion surface group can be obtained, such as γ1 and γ2. Figure 11The figure shows the statistical results of the inclination angle of the propulsion surface after a certain distance. A threshold for the inclination angle of the propulsion surface of the propulsion group can be set. This allows for automatic or manual adjustment of the propulsion surface to ensure that the inclination angle of the entire propulsion surface system is within an acceptable range, thereby achieving the integration of the propulsion system and ensuring that the entire working surface does not shift. Of course, the aforementioned method can also be used to check each propulsion surface individually to ensure that the inclination angle of each propulsion surface is within the threshold range. This is not limited here. Similarly, this invention can check the inclination angle by measuring the inclination angle at fixed times or by using fixed functions or tabular relationships to generate the inclination angle measurement verification time. Inclination angle measurement verification can also be adaptively inserted during the use process. The specific implementation method is not limited here.

[0042] The radar used in this invention can be a laser ranging radar, which has the advantage of obtaining both the distance and the angle between the propulsion surface, the radar line, and the entire propulsion plane. This allows it to adapt to various deployment scenarios and is not limited to the symmetrical arrangement assumption in the calculations above. To achieve similar functionality, when using millimeter-wave radar, this invention also needs to confirm the angle. However, millimeter-wave radar transmits waves spherically. The confirmation scheme is described in detail below: the radar transmits a modulated wave and mixes it with the echo reflected from the target. The Doppler effect caused by the path difference and velocity difference between the target and the radar system means that the intermediate frequency signal after mixing contains the range and velocity Dopplers of the target. By decoupling these components, the radial range and radial velocity components of the target can be obtained.

[0043] This radar system employs a linear frequency modulated (LFM) millimeter-wave radar, meaning the radar carrier frequency is in the millimeter-wave band, and the transmitted wave is frequency-modulated using a LFM mode. The frequency-modulated waveform used is as follows: Figure 12 As shown, its basic principle is: assuming the radar transmission waveform is...

[0044]

[0045] Its instantaneous phase Defined as

[0046]

[0047] The received waveform is

[0048]

[0049] The received waveform is the instantaneous phase. Defined as

[0050]

[0051] Assuming the target's radial distance is R, its radial velocity is V, and its time delay is τ, then

[0052]

[0053] The intermediate frequency signal S received by the radar system IF for

[0054]

[0055]

[0056] so,

[0057]

[0058] exist Figure 12 The sawtooth waveform can be obtained.

[0059]

[0060] For the Kth sawtooth wave T chirp ,

[0061] t K =t-KT chirp t K ∈[0,T chirp (10),

[0062] Substituting 9 and 10 into 2 further yields the following result:

[0063]

[0064] Substituting 4 and 10 into 7 yields the result.

[0065]

[0066] because Therefore, the last term in 12 can be omitted. Substituting 5 into 11, we get...

[0067]

[0068] so,

[0069]

[0070] From this, we can obtain

[0071]

[0072]

[0073] For intermediate frequency signal S IF The Fourier transform has

[0074]

[0075] Through Fourier transform, we can obtain the Doppler range of the target. However, the actual range is affected by the target's velocity. To obtain a precise range value, velocity correction is needed. Through step 17, we can obtain a function of K—the spectrum X. (ω,K) Its phase It varies with K. Therefore, we treat it as a discrete function and perform a Fourier transform on it:

[0076]

[0077] This allows us to obtain its velocity Doppler. We call this 2D-FFT.

[0078] To obtain the target's azimuth information (the angle between the line connecting the propulsion surface and the radar and the propulsion surface of the propulsion group), we use multiple receiving antennas for measurement. Because the spatial positions of the different receiving antennas are different, the path difference (phase) of the target echo varies. By calculating this difference, the target's azimuth can be measured.

[0079] After calculating the range and velocity of the target, its phase information can be obtained. The relationship between the phase difference Δφ between channels and the radar's angle of arrival θ is shown in the formula. In the formula, λ is the radar wavelength, and d is the antenna spacing. The inter-channel ratio was obtained through two different channels, channel 23 and channel 13.

[0080]

[0081]

[0082] In the formula, Δφ' 13 To calculate the phase difference of the 13 channels, Δφ 23 For the measured phase difference of the 23 channels, d 13 The antenna spacing is 13, d 23 The antenna spacing is 23.

[0083] In practical processing, since the phase is flipped in units of 2π, Δφ can be determined based on the antenna spacing between channels 23 and 13. 23 and Δφ 13 The winding range is thus used to obtain the measured Δφ that satisfies the phase range. 13 and the calculated Δφ' 13 Possible solutions. When Δφ 13 With Δφ' 13 If the phase difference is within a certain error range, the angle of arrival is considered correct, and the angle of arrival is calculated based on the phase difference of the 13 channels.

[0084] The basic calculation formula is:

[0085]

[0086] Equation 21 above can be used to determine the angle between the propulsion surface detected by the millimeter-wave radar and the radar line and the propulsion surface of the entire propulsion group, thereby achieving a detection result similar to that of lidar. Therefore, the solution of this invention can use existing millimeter-wave and / or lidar to achieve ranging and angle determination, which has stronger adaptability for the system.

[0087] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0088] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need further definition and explanation in subsequent figures. The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for controlling a coal mining face, characterized in that, It includes multiple driven coal mining faces connected by multiple drive units, wherein N coal mining faces form a propulsion group, where N is an integer greater than 1, and a propulsion group includes a millimeter-wave radar and / or a lidar, and multiple coal mining faces form M propulsion groups, where M is an integer greater than or equal to 2, and all adjacent propulsion groups of the M propulsion groups include at least one identical coal mining face, and the millimeter-wave radar and / or lidar in each propulsion group generates control signals to control each propulsion face in the propulsion group; Based on the relationship between the ranging accuracy of the millimeter-wave radar and / or lidar and the distance deviation between the two propulsion surfaces, a setting is obtained that associates the ranging accuracy of the millimeter-wave radar and / or lidar with the distance deviation threshold. Distance deviation during propulsion can be controlled by measuring the distance difference between two propulsion attempts before and after the same propulsion point within a threshold range; The millimeter-wave radar and / or lidar within the propulsion group contain k ranging waves input to the same propulsion surface, where k is an integer greater than or equal to 2. The k ranging waves obtain the tilt angle of the propulsion surface through k distances. Each pair of adjacent ranging waves emitted from k ranging waves has the same included angle; The parameters for determining the angle of the ranging wave include at least the ranging accuracy of the millimeter-wave radar and / or lidar within the propulsion group.

2. The coal mining face control method according to claim 1, characterized in that, The drive unit can linearly adjust the position of the coal mining face and also adjust the inclination angle of the coal mining face.

3. The coal mining face control method according to claim 1, characterized in that, The millimeter-wave radar and / or lidar within the propulsion group are configured with ranging accuracy based on a first distance deviation.

4. The coal mining face control method according to claim 3, characterized in that, The first distance deviation is the threshold of the maximum distance deviation among the plurality of coal mining faces.

5. The coal mining face control method according to claim 1, characterized in that, The inclination angle of the propulsion surface does not exceed the included angle threshold.

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