A high-precision alignment positioning control method for hydraulic support moving

Abstract

A kind of hydraulic support high-precision moving frame alignment positioning control method, (1) the adjacent two hydraulic supports are contacted each other, and the position of the hydraulic support is always constrained by its adjacent frame during moving frame;(2) displacement sensor is arranged in the base of hydraulic support;(3) first, the relative displacement between hydraulic supports is used as the basis to calculate the position information of each hydraulic support compared with the first frame, and the actual arrangement trajectory of hydraulic support is obtained;Then, the ideal trajectory of next moving frame and the moving distance of each hydraulic support needed to compensate straightness are calculated with the position of the most lagged hydraulic support as reference, finally, the moving distance of each hydraulic support should be calculated and moving frame action is completed in combination with the moving frame step distance set in advance, and the dynamic alignment of hydraulic support is realized during moving frame process.The present application makes the adjacent two supports keep direct contact, and controls the alignment and positioning of hydraulic support, avoids the problem of inconsistent moving frame direction angle caused by independent hydraulic supports.

Description

Technical Field

[0001] This invention relates to a control method for aligning and positioning hydraulic supports in a fully mechanized mining face, so as to keep the hydraulic supports in a neat arrangement, and belongs to the field of hydraulic support alignment control technology. Background Technology

[0002] Coal mining machines, hydraulic supports, and scraper conveyors are the core equipment of fully mechanized longwall mining faces (coal mine longwall mining faces equipped with fully mechanized equipment underground are called fully mechanized longwall mining faces), collectively known as the "three machines." These three machines cooperate and constrain each other during operation. As the main support equipment in fully mechanized longwall mining faces, achieving rapid follow-up of hydraulic supports is a key technology for realizing the "unmanned" and "intelligent" operation of fully mechanized longwall mining faces. Fully mechanized longwall mining faces require "three straight lines and one level line," namely, straight coal face, straight scraper conveyor, and straight hydraulic supports. This necessitates that the hydraulic supports be neatly arranged and maintain good straightness during operation.

[0003] The longwall mining face has a number of hydraulic supports, all of which are connected to the scraper conveyor. However, there is no direct positional constraint between adjacent hydraulic supports, and they are independent of each other, which makes it difficult to keep the hydraulic supports in a neat arrangement.

[0004] During the operation of a fully mechanized longwall mining face, the hydraulic support pushes the scraper conveyor via a pushing mechanism, advancing the conveyor towards the unmined coal face. Then, the hydraulic support is moved using the scraper conveyor as a base. The distance between the moving and pushing actions is generally determined by the stroke sensor data in the pushing cylinder. However, due to the large clearance between the connecting pin and the control pin of the pushing cylinder, and the fact that the pushing lug of the scraper conveyor's intermediate trough is typically a slotted hole, the actual pushing and moving distances of the hydraulic support deviate significantly from the stroke sensor values. This is especially problematic when the roof and floor conditions of the longwall mining face change, leading to difficulties in controlling the hydraulic support's posture and ensuring the support is properly positioned.

[0005] Currently, there are two main methods for controlling the straightness of hydraulic supports:

[0006] One approach involves using coal mining machine positioning technology to obtain the coal mining machine's trajectory. This is then used to infer the scraper conveyor's trajectory based on the positional constraints between the coal mining machine and the scraper conveyor. Combined with displacement sensors and straightening algorithms in the hydraulic support pushing jacks, the straightness of the scraper conveyor is corrected during the "pushing" process. Finally, the hydraulic support is aligned by "moving" the support with the zero displacement in the pushing cylinder as the target. This method uses the scraper conveyor's trajectory as the absolute reference direction, theoretically enabling high-precision alignment control of the hydraulic support. However, this approach requires high positioning accuracy for the coal mining machine, resulting in high costs. Furthermore, the stroke sensors in the hydraulic support pushing jacks cannot accurately reflect the displacement of the hydraulic support, making it difficult to achieve the desired alignment effect through the "moving" process.

[0007] Another method uses hydraulic supports as a reference, employing sensors such as displacement sensors, laser arrays, inertial sensors, and vision sensors installed on the hydraulic supports to obtain the relative position and attitude information between adjacent supports. During the "support alignment" process, adjacent supports are aligned, thereby controlling the straightness of the hydraulic support group. However, due to the large number of sensors, the cumulative measurement error of the hydraulic support movement distance makes it difficult to achieve high-precision hydraulic support alignment control. Furthermore, each hydraulic support operates relatively independently, lacking an absolute reference direction, which leads to significant deviations in the orientation angles of each hydraulic support, and the straightening direction of the hydraulic supports is not orthogonal to the mining roadway.

[0008] CN115822664A (2022115730001) discloses a fully digital electro-hydraulic control system for a hydraulic support, including a fully digital electro-hydraulic controller and interconnected with it a fully digital driver, a fully digital pressure sensor, a fully digital stroke sensor, a fully digital infrared receiver, and a fully digital attitude sensor. The fully digital electro-hydraulic controller is responsible for sending commands to the entire system and analyzing and processing the data collected by the sensors, sending action commands to the hydraulic support, receiving signals through the fully digital driver, and controlling the opening and closing of the corresponding electromagnetic pilot valves to realize the corresponding actions of the hydraulic support. This invention is used for digital control of hydraulic supports, but it cannot solve the problem of difficulty in positioning the support during the "moving" process.

[0009] CN111489391A (202010137452X) discloses a laser point cloud-based positioning system and method for advanced hydraulic supports, which can comprehensively monitor the position of the advanced hydraulic support in the advanced roadway of the working face and its positional relationship with the coal walls and equipment on both sides of the roadway. It includes: a traveling advanced hydraulic support, a 3D laser scanner, an infrared camera, and an advanced positioning controller. The 3D laser scanner and the infrared camera are communicatively connected to the advanced positioning controller. The advanced positioning controller is installed on the end hydraulic support and is used to receive point cloud data acquired by the 3D laser scanner and real-scene image information acquired by the infrared camera. Based on the real-scene image information, the point cloud data is filtered, and the current position of the advanced hydraulic support is determined according to the filtered point cloud data. This invention only monitors the working status of key equipment in the advanced roadway of the fully mechanized mining face and cannot solve the problem of difficulty in positioning the support during the "support relocation" process.

[0010] CN105000328A (2015103790251) discloses an automatic straightening device and method for the body of a scraper conveyor in a fully mechanized mining face. The device includes an elastic rod and a relative posture measuring device. The elastic rod is positioned between any two adjacent hydraulic supports, and an angle sensor is installed between the elastic rod and the hydraulic support. The relative posture measuring device includes an elastic connector positioned between any two adjacent central troughs, and the elastic connector is equipped with a strain sensor with temperature compensation. The angle sensor and strain sensor are connected to a signal processing system via a communication line. The signal processing system communicates with an electro-hydraulic control system via a data transmission module. The electro-hydraulic control system is connected to the hydraulic supports. This method uses the voltage signal received by the electro-hydraulic control system as a judgment basis and performs corresponding actions on the hydraulic supports and the scraper conveyor according to the actual working conditions, realizing the positioning of the hydraulic supports and the straightening control of the central trough of the scraper conveyor. This invention only automatically straightens the scraper conveyor body. Although an angle sensor is installed between the elastic rod and the hydraulic support, it cannot solve the problem of difficulty in positioning during the "support shifting" process. Summary of the Invention

[0011] To address the limitations of existing hydraulic support alignment and positioning technologies, this invention proposes a high-precision hydraulic support shifting alignment and positioning control method. This method ensures absolute positional constraints between adjacent supports, avoiding inconsistencies in shifting direction angles caused by the independent operation of hydraulic supports.

[0012] The high-precision hydraulic support shifting alignment and positioning control method of the present invention adopts the following scheme:

[0013] (1) Two adjacent hydraulic supports are brought into contact with each other. During the movement of the supports, the hydraulic supports are always constrained by the position of their adjacent supports, thereby ensuring that the direction angle of each hydraulic support is consistent with that of the first hydraulic support during the movement, and limiting the lateral displacement of the hydraulic supports.

[0014] (2) A displacement sensor is installed in the base of the hydraulic support to measure the relative displacement with the adjacent hydraulic support during the moving process;

[0015] (3) When moving the support, first calculate the position information of each hydraulic support relative to the first support (first hydraulic support) based on the relative displacement between the hydraulic supports, and obtain the actual arrangement trajectory of the hydraulic supports; then use the position of the most lagging hydraulic support as the reference to calculate the ideal trajectory of the next movement and the pushing distance of each hydraulic support to compensate for the straightness; finally, combine the pre-set movement step distance to calculate the pushing distance of each hydraulic support and complete the movement action, so as to realize the dynamic alignment of the hydraulic supports during the movement process.

[0016] The two adjacent hydraulic supports are in contact with each other by having a rack installed on one side of the hydraulic support base and a gear installed on the other side. During the movement of the supports, the gear or rack on one hydraulic support (this support) meshes with the rack or gear on its adjacent hydraulic support (the neighboring support), which can reduce the wear on the hydraulic support base during the movement.

[0017] The displacement sensor is a shaft encoder, installed in the gear of the hydraulic support base. It measures the angular velocity of the gear rotation during the movement of the support, and calculates the relative displacement with adjacent supports during the movement based on the circumference of the gear pitch. Because the gear is directly mounted on the hydraulic support base, the shaft encoder provides a more accurate measurement of the hydraulic support's travel distance.

[0018] The displacement of the hydraulic support calculated by the shaft encoder is:

[0019]

[0020] In the formula, s is the moving distance of the hydraulic support, ω is the gear speed output by the shaft encoder, a is the pitch circle length when the gear and rack mesh, and t0 is the moving time of the hydraulic support.

[0021] This invention improves the hydraulic support base, ensuring direct contact between adjacent supports and avoiding inconsistent movement angles caused by the independent operation of the hydraulic supports. Furthermore, it enhances the alignment and positioning control of the hydraulic supports. Compared to existing technologies, this invention has the following characteristics:

[0022] 1. By improving the base of the hydraulic support, each hydraulic support can only move parallel to the adjacent support and maintain the same direction angle during the support relocation process. Therefore, it is only necessary to determine that the moving direction of the first hydraulic support is perpendicular to the longwall face, thus avoiding the problem of inconsistent relocation directions of the hydraulic supports in the existing scheme.

[0023] 2. The solution proposed in this invention eliminates the spacing between hydraulic supports, constrains the lateral displacement of the hydraulic supports, and avoids the problem of difficult control of the spacing between supports in the original solution.

[0024] 3. The contact parts of each hydraulic support base use gears and racks meshing, and the gears have built-in shaft encoders, which can accurately measure the relative displacement between adjacent hydraulic supports. This replaces the stroke sensor in the push cylinder as the basis for determining whether the support has been moved, thus enabling high-precision measurement of the relative displacement of the hydraulic supports.

[0025] 4. Based on the relative displacement between hydraulic supports, a new hydraulic support straightness control scheme is proposed, that is, the straightness error of the arrangement is pre-calculated and compensated during each support movement process, thereby realizing the alignment control of the hydraulic support arrangement. Attached Figure Description

[0026] Figure 1 This is a top view of the base of the hydraulic support in this invention.

[0027] Figure 2 This is a left view of the base of the hydraulic support in this invention.

[0028] Figure 3 This is a right view of the base of the hydraulic support in this invention.

[0029] Figure 4 This is a schematic diagram of the hydraulic support relocation process in this invention.

[0030] Figure 5 This is a schematic diagram of the dynamic alignment of the hydraulic support in this invention.

[0031] Figure 6 This is a flowchart of the dynamic alignment control of the hydraulic support in this invention.

[0032] In the diagram: 1. Scraper conveyor trough, 2. Push cylinder, 3. Hydraulic support base, 4. Rack, 5. Push jack, 6. Gear, 7. Gear groove. Detailed Implementation

[0033] The high-precision hydraulic support alignment and positioning control method of the present invention aims to ensure absolute positional constraints between adjacent supports, thereby avoiding inconsistencies in the movement direction angles caused by the independent operation of hydraulic supports. The technical solution proposed in this invention includes the following aspects.

[0034] First aspect: Propose improvements to the hydraulic support base.

[0035] To keep the hydraulic supports neatly arranged, this invention places two adjacent hydraulic supports in contact with each other. During the movement of the supports, the hydraulic supports are always constrained by the position of the adjacent supports, thereby ensuring that the direction angle of each hydraulic support is consistent with that of the first hydraulic support during the movement, and effectively limiting the lateral displacement of the hydraulic supports.

[0036] Because the improved hydraulic support base is in direct contact with adjacent supports, wear will occur during the support relocation process. To avoid this problem, this invention employs a rack and pinion drive system, with a rack installed on one side of the hydraulic support base and a gear installed on the opposite side. During the support relocation process, the gear (rack) on one hydraulic support (this support) meshes with the rack (gear) of its adjacent hydraulic support (the next support), thereby reducing wear on the hydraulic support base during the relocation process.

[0037] The second aspect: Proposing a hydraulic support stroke measurement scheme.

[0038] This invention improves the hydraulic support base, ensuring consistent directional angles during the hydraulic support's movement. However, the stroke sensor in the hydraulic support's pushing cylinder cannot accurately reflect the movement distance, making accurate alignment and positioning difficult. To solve this problem, this invention integrates a shaft encoder into the gear on the improved hydraulic support base. This encoder measures the angular velocity of the gear's rotation during movement, and combined with the gear pitch circumference, the relative displacement with adjacent supports can be calculated. Since the gear is directly mounted on the hydraulic support base, the shaft encoder provides more accurate measurements of the hydraulic support's movement stroke.

[0039] Thirdly: Propose a hydraulic support alignment control scheme.

[0040] To reduce the impact of accumulated errors from sensors (shaft encoders built into gears) on the positioning and straightness of hydraulic supports, this invention proposes a novel hydraulic support alignment control scheme. First, based on the relative displacement between hydraulic supports, the position information of each hydraulic support relative to the first support is calculated, and the actual arrangement trajectory of the hydraulic supports is obtained. Then, using the position of the most lagging hydraulic support as a reference, the ideal trajectory for the next support movement and the pushing distance required to compensate for the straightness of each hydraulic support are calculated. Finally, combined with the pre-set movement step distance, the pushing distance that each hydraulic support should move is calculated, and the movement action is completed, achieving dynamic alignment of the hydraulic supports during the movement process.

[0041] The technical solutions disclosed in this invention will now be described more clearly and comprehensively with reference to the accompanying drawings and embodiments. It should be noted that the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments described in this invention without creative effort are also protected by this invention.

[0042] like Figure 1 As shown, in order to allow the bases 3 of two adjacent hydraulic supports to contact each other, gears 6 and racks 4 are respectively provided on both sides of the hydraulic support base 3. The gear 6 on one hydraulic support base 3 meshes with the rack 4 on its adjacent hydraulic support base. The rack 4 is installed (welded) on the left side of the hydraulic support base 3, see [reference]. Figure 2 And it is parallel to the lower plane of the hydraulic support base 3. See also Figure 3 Four gear slots 7 are cut out on the right side of the hydraulic support base 3. The four gear slots 7 are arranged in parallel, and a gear 6 is installed in each gear slot. The height of the gear 6 is the same as the height of the rack 4.

[0043] The hydraulic support base designed in this invention is arranged on the working surface and its working process is as follows: Figure 4 As shown, the center distance of the hydraulic supports is set to 1.7m, and the step distance for moving the supports is set to 0.6m. During installation, the orientation angle of the first hydraulic support must first be calibrated, that is, to ensure that the moving direction of the first hydraulic support is orthogonal to the mining roadway. The other hydraulic supports are then sequentially meshed with each other through racks and gears, and the moving orientation angle is consistent with that of the first hydraulic support.

[0044] When moving the frame, use the middle trough 1 of the scraper conveyor (see...) Figure 1 Based on this, the piston rod of the push cylinder 2 on a hydraulic support (this support) retracts, guiding the hydraulic support to move towards the coal wall. At this time, the rack on this support meshes with the gear on the adjacent hydraulic support on its left, and the gear on this support meshes with the rack on the adjacent hydraulic support on its right. Due to the positional constraints of the adjacent supports on the left and right, the direction angle remains stable during the support movement, and there will be no deviation in the support movement direction. Furthermore, at least three gears are kept in mesh with the rack on the adjacent supports during the support movement, ensuring the stability of operation.

[0045] During the movement of the hydraulic support, the rolling speed and distance of gear 6 accurately reflect the movement speed and displacement. Since the two gears closest to and farthest from the middle trough 1 of the scraper conveyor may be suspended during the movement, shaft encoders are only installed in the two middle gears to measure the relative displacement of adjacent hydraulic supports. The movement displacement of the hydraulic support calculated using the shaft encoders is:

[0046]

[0047] In the formula, s is the moving distance of the hydraulic support, ω is the gear speed output by the shaft encoder, a is the pitch circle length when the gear and rack mesh, and t0 is the moving time of the hydraulic support.

[0048] from Figure 4 As can be seen, the coal mining machine cuts coal from bottom to top. After the coal mining machine cuts the coal, hydraulic support No. 37 is completing its shifting action. Because the hydraulic support is constantly constrained by hydraulic supports No. 36 and No. 38 during the shifting process, this support (hydraulic support No. 37) remains parallel to the adjacent supports during the movement. Furthermore, the shifting stroke of hydraulic support No. 37 is measured in real time by the shaft encoder in the gear, and the shifting stops after reaching the preset shifting step distance. After hydraulic support No. 37 completes its shifting, hydraulic supports No. 1 through No. 36 all complete their shifting actions according to this process. Due to the direct positional constraints between the hydraulic supports in the working face, the shifting direction remains orthogonal to the mining roadway even after multiple actions. Moreover, because the shaft encoder in the gear can more accurately measure the displacement of the hydraulic supports, the cumulative error during the shifting process is significantly reduced.

[0049] When the straightness error of the hydraulic support is large, dynamic alignment of the hydraulic support is required. A schematic diagram of dynamic alignment of the hydraulic support in a fully mechanized mining face under the northeast coordinate system is shown below. Figure 5 As shown. After completing the (n-1)th coal cutting and frame shifting, the relative displacement of each hydraulic support is measured by the shaft encoder in gear 6. Then, the position information of each hydraulic support relative to the first hydraulic support and the arrangement trajectory L of the hydraulic supports are calculated. n-1 In trajectory L n-1 Select the point that lags behind the working face in the direction of movement, and draw a reference line m perpendicular to the direction of working face movement through this point. n-1 By shifting the straight line a distance H in the direction of the working face, the ideal trajectory G of the hydraulic support after the nth coal cutting and support shift can be obtained. n By calculating the relative displacement between the hydraulic supports, the trajectory L can be obtained. n-1 The reference straight line m is the distance from each hydraulic support moving point. n-1 vertical distance d i,n-1 Where i represents the i-th hydraulic support transfer point, and d i,n-1 This refers to the straightness error that needs to be compensated for during the frame-shifting process. Compare this to the ideal trajectory G. n and trajectory L n-1 , will (Hd i,n-1 The distance L represents the movement of the i-th moving point during the n-th moving process. This movement is completed under the influence of sensor measurement errors and moving errors, thus forming the actual arrangement trajectory L of the hydraulic support for the next movement. n .

[0050] In the arrangement trajectory Ln Find the point of greatest lag in the middle, and draw a straight line m perpendicular to the working face advance direction through that point. n Using this as a reference line, the line is then translated in the direction of the working face advance to obtain the ideal arrangement trajectory G for the (n+1)th frame movement. n+1 The measurement and calculation process is repeated during the nth frame relocation to complete the (n+1)th frame relocation. By cyclically following this process, the straightness error of the hydraulic support arrangement can be continuously corrected, thereby achieving dynamic alignment of the hydraulic supports and controlling the cumulative error of the sensors within a small range. The dynamic alignment process is as follows: Figure 6 As shown.

Claims

1. A high-precision hydraulic support shifting, alignment, and positioning control method, characterized in that: (1) Two adjacent hydraulic supports are brought into contact with each other. During the movement of the supports, the hydraulic supports are always constrained by the position of their adjacent supports, thereby ensuring that the direction angle of each hydraulic support is consistent with that of the first hydraulic support during the movement, and limiting the lateral displacement of the hydraulic supports. (2) A displacement sensor is installed in the base of the hydraulic support to measure the relative displacement with the adjacent hydraulic support during the moving process; (3) When moving the frame, first calculate the position information of each hydraulic support relative to the first frame based on the relative displacement between the hydraulic supports, and obtain the actual arrangement trajectory of the hydraulic supports; then use the position of the most lagging hydraulic support as the reference to calculate the ideal trajectory of the next frame movement and the pushing distance of each hydraulic support to compensate for the straightness; finally, combine the pre-set frame movement step distance to calculate the pushing distance of each hydraulic support and complete the frame movement action, and realize the dynamic alignment of the hydraulic supports during the frame movement process; The two adjacent hydraulic supports are in contact with each other by having a rack installed on one side of the hydraulic support base and a gear installed on the other side. During the movement of the supports, the gear or rack on one hydraulic support meshes with the rack or gear on its adjacent hydraulic support. The displacement sensor is a shaft encoder, which is installed in the gear of the hydraulic support base to measure the angular velocity of the gear rotation during the frame movement process. Based on the circumference of the gear pitch, the relative displacement with the adjacent support during the frame movement process is calculated.

2. The high-precision hydraulic support shifting alignment and positioning control method according to claim 1, characterized in that: The displacement of the hydraulic support calculated by the shaft encoder is: In the formula, This represents the moving distance of the hydraulic support. The gear speed output by the shaft encoder. The pitch circle circumference when the gear and rack mesh. This refers to the time required to move the hydraulic support.

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