Intelligent integrated automatic pollution discharge, spray and dust suppression system for coal mine tunnel

Abstract

The invention discloses an intelligent integrated automatic pollution discharge, spray and dust suppression system for a coal mine tunnel, and relates to the technical field of automation. The system comprises a double-channel sensing assembly, a central controller, a mine communication link and an integrated pollution discharge spraying terminal group, the central controller obtains a dust image and a ground height image at the same time in combination with the double-channel sensing assembly, generates a roadway working condition grid map, completes dust level marking and ground height marking, extracts a dust cluster and a transition zone on the basis, and loads a pollution discharge component list. Constructing a descending chain from the outer edge of the dust cluster, selecting a ridge chain backbone, finally generating a cooperative control instruction set, issuing the cooperative control instruction set to the integrated pollution discharge spraying terminal group, and carrying out snapshot acceptance check by using a dual-channel sensing assembly after execution. According to the invention, accurate dust control, smooth sewage discharge and high resource utilization rate can be ensured, and the stability and long-term effectiveness of system operation can be maintained in a complex environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automation technology, in particular to an intelligent integrated automatic pollution discharge and spray dust-settling system for coal mine tunnels. BACKGROUND

[0002] Dust and sewage problems during the operation of coal mine tunnels have always been the core problems of mine safety and environmental management. In order to suppress dust concentration and protect the breathing environment of miners, while avoiding secondary dusting and equipment corrosion caused by sewage accumulation, the existing technology has proposed a variety of solutions. A common solution is to use a spray device to spray dust-settling in the tunnel at regular intervals or at fixed points, and to use a drainage ditch, a water collection pit and a pump pit to discharge water and sediments. This technology can reduce dust concentration to some extent and keep the ground in the tunnel basically clean, but there are still many limitations.

[0003] In terms of spray dust-settling, traditional spray systems mostly use fixed nozzles or manually mobile spray equipment. These systems usually spray at time intervals rather than according to the real-time distribution of dust in the tunnel. Due to the lack of intelligent sensing, the spray position often does not match the high concentration area, resulting in insufficient spraying in high concentration areas and excessive spraying in low concentration areas. The unevenness of the spray effect not only increases the amount of water used, but also may cause local water accumulation in the tunnel. In addition, the water vapor and dust mixture produced by spraying will settle along the low-lying areas, but the existing technology lacks a process design to push the dust into the pollution discharge member, so that the settled dust cannot be efficiently discharged and is prone to accumulate in low-lying areas of the tunnel. In terms of sewage discharge, the existing technology mainly relies on fixed drainage ditches, water collection pits and pump pits. These facilities are usually located at the construction stage, and lack dynamic adaptation capability. When the flow direction of the liquid-solid mixture after spraying does not match the existing drainage member, the discharge efficiency is significantly reduced. In actual operation, water accumulation and dust deposition often occur in areas without pollution discharge members, causing local blockage and even secondary disasters. Although some studies have proposed the use of portable water pumps or temporary hoses to enhance drainage, these measures rely on manual deployment, are inefficient and lack automation features. SUMMARY

[0004] In view of this, the present application provides an intelligent integrated automatic pollution discharge and spray dust-settling system for coal mine tunnels, which realizes synchronous sensing of dust and terrain, coordinated control of spraying and pollution discharge, and automatic verification of effect, and can form a continuous dust-settling and pollution discharge process in the coal mine tunnel, thereby ensuring accurate dust control, smooth sewage discharge, high resource utilization rate, and maintaining the stability and long-term effectiveness of system operation in complex environments.

[0005] The technical solution adopted by the present application is as follows:

[0006] The system comprises a double-channel sensing component, a central controller, a mine communication link and an integrated pollution discharge and spray terminal group. The central controller is used to: acquire dust images and ground height images at the same time through the double-channel sensing component; generate a roadway working condition grid map, complete dust level labeling and ground height labeling, extract dust clusters and transition zones, and load a pollution discharge component list; based on the roadway working condition grid map and the pollution discharge component list, construct a descending chain from the outer edge of the dust cluster according to the eight-direction adjacency rule, select the ridge chain backbone according to the number of passes, and implement the minimum bypass for single grid gaps caused by blockage; along the ridge chain, the end is traced back to the front to preferentially lock the sink adjacent to or in the same position as the pollution discharge component list, and determine the standby sink at the relatively low position and the grid unit where multiple chains intersect; a spray induction zone is laid out along the outer edge of the dust cluster, and a turning spray position and an end spray position are set; corresponding pollution discharge extraction nodes are determined; the spray induction zone and the pollution discharge extraction nodes form a phase-locked zone with spray first and pollution second, and are executed according to priority; a cooperative control instruction set is generated and issued to the integrated pollution discharge and spray terminal group through the mine communication link for execution; and after the execution of the cooperative control instruction set, the double-channel sensing component acquires a snapshot of the same working condition for acceptance.

[0007] Further, the double-channel sensing component comprises a dust imaging channel and a ground depth channel, which acquire a single snapshot at the same time; the dust imaging channel is a dust camera installed on the roof or sidewall of the roadway, and its output is a single frame of dust image; the central controller calls its built-in thresholding grading function to divide the dust image into three categories: high, medium and low, to obtain a dust level labeling map; the ground depth channel is a depth scanner facing the floor of the roadway, and its output is a single frame of ground height image; the central controller performs built-in plane correction and attitude compensation to align the ground height image to a unified coordinate, generating a ground height labeling map, in which each position is labeled as relatively high, relatively medium or relatively low.

[0008] Further, the pollution discharge component list is preloaded in the static engineering table of the central controller during equipment installation and debugging, including the fixed positions of drainage outlets, sump pits, pump pits and diversion groove valves; the central controller takes the roadway reference line as the longitudinal reference, divides the equidistant grid according to the effective coverage width of a single spray head, and generates a roadway working condition grid map; project the dust level labeling map and the ground height labeling map onto the roadway working condition grid map, so that each grid unit has dust level labeling, ground height labeling and obstacle state labeling; if the ground depth channel identifies a protruding obstacle, the obstacle state labeling of the grid unit is blocked, otherwise it is passable.

[0009] Further, the central controller defines a dust cluster on the roadway working condition grid map as a set of grid cells adjacent to each other and marked as high dust level, and defines a transition zone as a set of grid cells adjacent to the dust cluster and marked as medium dust level. The central controller defines a falling candidate set of a passable grid cell as a set of falling adjacent grid cells of the passable grid cell. The central controller defines a local low grid cell as a passable grid cell without falling adjacent grid cell.

[0010] Further, the central controller generates a falling chain from each dust cluster, including: selecting all high dust level grid cells on the outer edge of the dust cluster as a set of falling chain start points; starting from each falling chain start point, extending the falling chain in the following order: if there is a relatively low grid cell in the falling candidate set, entering the one closest to the direction of the start point; if there is only a relatively medium grid cell, entering any one of the grid cells with the smallest change in the current direction of travel; if a block is encountered, terminating the branch at the block; when a grid cell has two or more falling adjacent grid cells, generating parallel branches to continue growing; when a local low grid cell is entered and none of its adjacent grid cells has a lower mark, terminating the branch.

[0011] Further, the central controller generates a falling chain from each dust cluster, including: selecting all high dust level grid cells on the outer edge of the dust cluster as a set of falling chain start points; starting from each falling chain start point, extending the falling chain in the following order: if there is a relatively low grid cell in the falling candidate set, entering the one closest to the direction of the start point; if there is only a relatively medium grid cell, entering any one of the grid cells with the smallest change in the current direction of travel; if a block is encountered, terminating the branch at the block; when a grid cell has two or more falling adjacent grid cells, generating parallel branches to continue growing; when a local low grid cell is entered and none of its adjacent grid cells has a lower mark, terminating the branch.

[0012] Further, the central controller generates a falling chain from each dust cluster, including: selecting all high dust level grid cells on the outer edge of the dust cluster as a set of falling chain start points; starting from each falling chain start point, extending the falling chain in the following order: if there is a relatively low grid cell in the falling candidate set, entering the one closest to the direction of the start point; if there is only a relatively medium grid cell, entering any one of the grid cells with the smallest change in the current direction of travel; if a block is encountered, terminating the branch at the block; when a grid cell has two or more falling adjacent grid cells, generating parallel branches to continue growing; when a local low grid cell is entered and none of its adjacent grid cells has a lower mark, terminating the branch.

[0013] Further, if the sink corresponds to the fixed facility in the list of pollution discharge components, the facility position is designated as a pollution extraction node; if a backup sink is used, a mobile pollution discharge port is set in the adjacent grid direction of the position, and it is designated as a pollution extraction node, and its connection relationship is completed through the standard interface of the terminal group.

[0014] Further, the central controller binds the spray induction zone with the pollution extraction node in pairs to form a phase-locked zone with spray first and pollution following; the advancing direction is from the dust cluster to the sink along the ridge chain; when two or more phase-locked zones of the dust cluster need to occupy the same spray nozzle or the same valve group in the same time window, the number of high-zone grid units of the dust cluster is used as the priority basis, and the high one goes first and the low one is delayed; the delay result is written into the staggered sequence of the cooperative control instruction set; if there are passable grid units on the outer edge of the dust cluster that are not covered by any spray induction position, a compensation spray position is automatically set between the grid unit and the ridge chain and is incorporated into the current phase-locked zone; the central controller writes the advancing sequence of the ridge chain, the sink, the spray induction zone, the pollution extraction node, and the phase-locked zone corresponding to each dust cluster into the cooperative control instruction set and issues it to the integrated pollution spray terminal group through the mine communication link for execution, so that the dust is continuously pushed to the sink along the ridge chain and is synchronously extracted to complete dust suppression and pollution discharge.

[0015] By using the above technical solutions, the present application has the following beneficial effects: through the extraction of the dust cluster and the transition zone, the central controller can clearly define the boundary of the treatment object, thereby reducing over-reaction and improving resource utilization during spray coverage. After loading the list of pollution discharge components, the algorithm can accurately connect the extraction path with the existing facilities to avoid the accumulation of liquid-solid mixture in areas without discharge capacity. Further, the sink is preferentially locked along the ridge backbone from the end to the front, and if it is not hit, a relatively low and multi-chain intersection position is selected as a backup sink, thereby ensuring that the liquid-solid mixture is guided to a reliable pollution discharge node in the shortest path. The laying of the spray induction zone and the setting of the turning spray position and the end spray position make the advancing surface geometrically continuous and complete, effectively preventing the spread of dust at the corners or the end section. By forming a phase-locked zone with spray first and pollution following from the spray induction zone and the pollution extraction node, the central controller can realize phased and rhythmic treatment, ensure the coupled execution of spray and extraction actions, and improve the overall dust suppression and pollution discharge efficiency. The priority and staggered execution strategy further avoids resource conflicts between spray nozzles and extraction equipment, enabling the system to remain stable in complex environments. The generation and issuance of the cooperative control instruction set enable all actions to be executed automatically in an orderly manner, reducing manual intervention and improving response speed. Finally, after execution, a snapshot of the same working condition is taken again for acceptance, realizing self-checking and one-time correction of the treatment effect, thereby maintaining the continuous effectiveness of dust suppression and pollution discharge in the dynamically complex coal mine roadway environment. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a system structure schematic diagram of an intelligent integrated automatic pollution discharge spraying dust reduction system for a coal mine roadway in an embodiment of the present application;

[0017] Figure 2 is a roadway working condition grid diagram and dust cluster ridge chain construction analysis schematic diagram in an embodiment of the present application;

[0018] Figure 3 is an integrated pollution discharge spraying terminal group collaborative execution timing and peak-shaving control schematic diagram in an embodiment of the present application. DETAILED DESCRIPTION

[0019] All features disclosed in this specification, and / or all steps of any methods or processes disclosed in this specification, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0020] Any of the features disclosed in this specification, unless explicitly stated otherwise, may be replaced by alternative features functioning to accomplish broadly similar purposes. That is, unless expressly stated otherwise, each feature is one of a number of equivalent or similar features.

[0021] REFERENCE Figure 1 An intelligent integrated automatic pollution discharge spraying dust reduction system for a coal mine roadway, the system comprising: a dual-channel sensing assembly, a central controller, a mine communication link, and an integrated pollution discharge spraying terminal group.

[0022] The central controller records the installation position, orientation, and relative distance of the dust imaging channel and the ground depth channel in the dual-channel sensing assembly during the installation and debugging stage, and establishes a unified coordinate system. The unified coordinate system takes the roadway reference line as the longitudinal reference and the equipment installation surface as the transverse reference. To ensure consistent geometric mapping of the two channels during operation, the central controller arranges fixed reference marks on the roadway floor and records the positional relationship of the reference marks in the field of view of the two channels as long-term calibration anchor points. The advantage of this is that when the equipment produces a small pose offset due to vibration, the position change of the reference mark can be used for quick compensation, avoiding pixel misalignment in subsequent fusion and ensuring that the dust image and the ground height image can be one-to-one corresponding in the unified coordinate system.

[0023] The central controller sends a collection trigger signal to the dust imaging channel and the ground depth channel at the same time through the synchronization line, requiring both channels to start exposure or ranging at the same trigger edge. To avoid time deviation caused by internal processing delay of both channels, the central controller reads the hardware time stamp of both channels after triggering and sets a time consistency threshold, for example, no more than 5 milliseconds. Collection results exceeding the threshold are discarded and immediately retriggered. In this way, consistency at the same time can still be maintained in a scene where coal dust disturbance changes rapidly, ensuring that the dust distribution reflected by the dust image and the terrain state reflected by the ground height image strictly correspond in time.

[0024] The dust imaging channel faces the roadway space, and the central controller receives a single frame of raw image after triggering. To suppress the point-like false light caused by strong reflective particles in the roadway, the central controller first performs small-scale spatial filtering, which only weakens isolated bright spots without affecting continuous dust strips. Then dynamic range compression is performed to narrow the large difference between light and dark areas to a uniform gradable gray scale interval, facilitating subsequent grading. In order to make the dust image focus more on suspended dust rather than the texture of fixed components, the central controller performs top hat enhancement on the low-frequency background to highlight the cloud-like texture formed by fine particles. Then the thresholding grading function is called to divide the pixels into three categories: high, medium and low. The reason for using a grading function instead of a single threshold is that the roadway lighting is spatially non-uniform, and multi-threshold grading can adaptively consider both bright and dark areas in the same frame, reducing the voids or adhesions caused by false segmentation. After processing, the dust image is formed, along with the time stamp and unified coordinate index of the frame.

[0025] The ground depth channel faces the roadway floor, and the central controller receives a single frame of ranging result after triggering. Due to the presence of water film and slippery surface in the roadway, the depth return may contain multiple echoes. The central controller counts the energy distribution of each ranging unit and selects the main energy peak near the sensor side as the valid echo, discarding the weak peak far away. This can effectively exclude false long-distance values caused by water surface specular reflection or distant wall, ensuring that the real distance directly contacted with the ground is taken. Subsequently, the central controller uses the attitude information recorded during the installation and debugging stage to perform plane correction and attitude compensation, eliminating the systematic deviation caused by inclined installation, so that the ground appears as an approximately horizontal distribution in the unified coordinate system. In order to obtain a more stable ground height image, the central controller performs connectivity check within the neighborhood, only retaining the depth area connected to the large area of ground and eliminating the isolated depth segments of suspended objects or hanging cables. Finally, the central controller divides the relative height into three grades: relative high, relative medium and relative low, generating the ground height image. The reason for using three-grade division is that the relative slope and convergence relationship are concerned in the spray induction and pollution path arrangement, and too fine continuous values not only have no additional benefit to control decisions, but also amplify the influence of sensor noise.

[0026] The dual-channel perception component adopts a coaxial integration scheme to align the optical centers of the dust imaging channel and the ground depth channel as much as possible, and the central controller controls the simultaneous acquisition of the two channels through the same trigger interface. In this way, the edge misalignment caused by parallax can be fundamentally reduced, and the dependence on complex geometric compensation can be reduced. The dust imaging channel uses short pulse narrowband illumination, and the ground depth channel uses ranging pulses at the same time. The central controller interleaves the two pulses in time with an interval of less than 1 millisecond, which maintains the consistency of "the same time" and avoids mutual interference between the two light sources. The advantage of interleaving is that the short pulse of the dust imaging can freeze the high-speed drifting fine particles, reduce the smear, and minimize the scattered light leakage in the depth channel echo acquisition. The ground depth channel is prone to multiple reflections on a wet and slippery floor. The central controller forms an energy distribution for each ranging unit and selects the main energy peak near the sensor side as the effective echo. This selection can preferentially obtain the shortest path return from the actual contact surface and avoid false long distances caused by secondary reflections, so that the ground height image can still be stably obtained in the presence of water and oil.

[0027] On the black coal surface and the wet mud surface, the natural texture of the ground depth channel is insufficient. The central controller controls the depth channel to project a known texture at the same time of ranging. The known texture produces stable light and dark undulations on the ground, providing the ranging algorithm with sufficient matching features. This can improve the effective ranging rate in low reflection conditions and avoid large-area holes in the ground height image. In order to avoid the crosstalk of the active texture to the dust image, the central controller selects a different spectral range from the dust imaging channel for projection, and cooperates with the bandpass filter during dust imaging acquisition. The bandpass filter can maximize the suppression of non-target spectra, improve the contrast of the particle cloud in the dust image, and reduce the misclassification caused by background texture.

[0028] The central controller sets a consistency tolerance for the timestamps of the two channels, for example, no more than 5 milliseconds. When there is strong convection in the roadway or the spray has just started, the dust distribution changes faster, and the central controller automatically tightens the tolerance, for example, no more than 2 milliseconds. Through adaptive tolerance, strictness at the same time is ensured, and excessive frame loss under stable working conditions is avoided. If small-area holes appear in the ground height image, the central controller searches for continuous and reliable depth areas in the longitudinal and transverse directions of the roadway in the unified coordinate system, and fills the small-area gaps by using adjacent interpolation. The reason for choosing the adjacent direction is that the roadway floor usually slowly undulates along the longitudinal direction and slightly tilts in the transverse direction in engineering construction, and adjacent interpolation can maintain the continuity of the terrain without introducing terrain features from a distance. When there is water accumulation on the ground to form a mirror surface, strong reflection points will appear in the dust imaging channel. The central controller marks these overlapping pixels as water surface reflections and reduces their weight in dust classification based on the overlapping relationship between continuous low areas in the ground height image and isolated strong bright spots in the dust image. This can avoid misjudging the high brightness of the water surface as high dust, thereby maintaining the sensitivity of the dust image to the real particle cloud.

[0029] The central controller divides the working area into equidistant square grids with the reference line of the roadway as the longitudinal reference, and the side length is the effective coverage width of a single spray nozzle, ensuring that each subsequent spray instruction can correspond to several grid units one by one. The advantage of square grids is that they naturally support eight-way adjacency, which facilitates subsequent expression of diagonal slope paths without increasing computational complexity. The dust image and the ground height image obtained at the same time are mapped to the grid coordinates according to the external parameter relationship during installation and debugging, so that each grid unit has a pixel set of the dust image and a ranging set of the ground height image. Aligning to the same grid coordinates avoids repeated coordinate conversion during path construction, reduces cumulative errors, and ensures that dust information and terrain information at the same position can be directly combined for judgment.

[0030] The central controller classifies the pixel brightness distribution of the dust image in the grid cell as high, medium or low. The reason for using classification instead of a single threshold is that the lighting in the tunnel is uneven, and classification can adapt to both bright and shadow areas in the same frame, avoiding misjudgment of dust of the same concentration as different levels in different light, so as to get a more coherent dust level label in space. The ranging set in the grid cell is robustly valued, and the ranging value corresponding to the main energy peak near the sensor side is preferentially used, and the weak peak on the far side is discarded. The main energy peak near the sensor side is more likely to come from the real reflection of the ground, while the weak peak on the far side is often caused by the mirror reflection of the water surface or the structure far away. Retaining the main energy peak can improve the representativeness of the ground height image to the real terrain. Then, the relative height is divided into relative high, relative medium and relative low, so that the ground height label directly reflects the slope trend, but does not overemphasize the sensor noise. On the tunnel working condition grid map, the high grid cell is aggregated in connectivity by eight-way adjacency, and a plurality of connected sets are obtained, each connected set defining a dust cluster; the medium grid cell adjacent to the outer edge of the dust cluster is bound as a transition zone. Using eight-way adjacency instead of four-way adjacency can include the oblique continuous high area in the same connected set, which is consistent with the actual situation of the oblique strip distribution of coal dust under the action of air flow and spraying. The purpose of binding the medium area as a transition zone is to reserve a buffer edge for subsequent spray induction, avoiding edge rebound and re-diffusion caused by only acting on the high area.

[0031] The central controller maps the drainage ditch, sump, pump pit and diversion channel valve position in the pollution control component list to the corresponding grid index in the roadway working condition grid map, and checks whether the positions around are marked as blocked. This step does not directly change the shape of the dust cluster and the transition zone, but provides engineering anchor points for subsequent construction of the descending chain from the outer edge of the dust cluster and subsequent path landing constraints, avoiding the final pointing of the path to the area without emission capacity. All high area grid cells adjacent to non-high area grid cells in the dust cluster are defined as the outer edge, which is used as the starting edge of the descending chain. This selection can make the path start from a position with a larger dust concentration gradient, making it easier to produce a stable convergence towards the low position. For any passable grid cell, if any of its eight adjacent grid cells has a lower ground level than the cell, the adjacent grid cell is recorded as the descending neighbor of the cell. Taking "lower" as the priority direction of advancement, the path can naturally move in the direction of slope descent, reducing the back-and-forth exploration in flat areas. After selecting the starting point from the outer edge, the central controller extends the path in the following order: if there is a relatively low position in the descending neighbor, it is preferred to enter the grid closest to the direction of the starting point, so that the path can maintain a straight line as much as possible and reduce the turning back; if there is only a relatively medium position, enter the grid with the smallest direction change to ensure continuous advancement when there is no obvious slope; if the front is blocked, terminate the branch at the block to avoid large-scale deviation caused by detouring. When a grid cell has two or more descending neighbors, parallel branches are simultaneously derived to continue growing, fully preserving the multiple downward channels that may exist in the terrain as a basis for subsequent statistics. After the above process, each dust cluster obtains several descending chains with clear start and end points.

[0032] The central controller maps the drainage ditch, sump, pump pit and diversion channel valve position in the pollution control component list to the corresponding grid index in the roadway working condition grid map, and checks whether the positions around are marked as blocked. This step does not directly change the shape of the dust cluster and the transition zone, but provides engineering anchor points for subsequent construction of the descending chain from the outer edge of the dust cluster and subsequent path landing constraints, avoiding the final pointing of the path to the area without emission capacity. All high area grid cells adjacent to non-high area grid cells in the dust cluster are defined as the outer edge, which is used as the starting edge of the descending chain. This selection can make the path start from a position with a larger dust concentration gradient, making it easier to produce a stable convergence towards the low position. For any passable grid cell, if any of its eight adjacent grid cells has a lower ground level than the cell, the adjacent grid cell is recorded as the descending neighbor of the cell. Taking "lower" as the priority direction of advancement, the path can naturally move in the direction of slope descent, reducing the back-and-forth exploration in flat areas. After selecting the starting point from the outer edge, the central controller extends the path in the following order: if there is a relatively low position in the descending neighbor, it is preferred to enter the grid closest to the direction of the starting point, so that the path can maintain a straight line as much as possible and reduce the turning back; if there is only a relatively medium position, enter the grid with the smallest direction change to ensure continuous advancement when there is no obvious slope; if the front is blocked, terminate the branch at the block to avoid large-scale deviation caused by detouring. When a grid cell has two or more descending neighbors, parallel branches are simultaneously derived to continue growing, fully preserving the multiple downward channels that may exist in the terrain as a basis for subsequent statistics. After the above process, each dust cluster obtains several descending chains with clear start and end points.

[0033] In the scene where the effective coverage width of the spray nozzle varies greatly, the central controller can set two levels of grid lengths in the longitudinal and transverse directions respectively, so that the longitudinal length aligns with the spray coverage length, and the transverse length aligns with the spray coverage width. In this way, one spray instruction can cover as many grid units as possible, reducing repeated or missed execution at the boundary. When an individual grid unit is marked as a high area due to a bright isolated peak, but the surrounding areas are all low areas, the central controller performs consistency correction in a small local neighborhood, and corrects the isolated high area to a medium area. In this way, the false aggregation caused by random high-brightness particles can be suppressed, and unnecessary small dust clusters can be avoided, so that the outer edge of the dust cluster is smoother, which is beneficial for the descending chain to start from the continuous boundary. When there is only a small difference in relative height between two adjacent grids and the sawtooth appears continuously along the longitudinal direction of the roadway, the central controller uniformly marks the middle section as a relative median, so that the slope expression changes from a fine step to a continuous gentle slope, which helps the descending chain to maintain stable progress on the slightly undulating ground without direction shaking.

[0034] For high area grid units located on the outer edge of multiple dust clusters at the same time, the central controller preferentially starts the descending chain from the position of the outer edge of the dust cluster with a larger area. Larger dust clusters usually correspond to more significant source intensity, and preferential processing can make subsequent spray and exhaust resource allocation more consistent with the management priority. When two descending neighbors have the same relative low degree and the same deviation from the direction of the starting point, the central controller preferentially selects the one that is more parallel to the reference line of the roadway. In this way, the backbone of the ridge chain can be more easily continuously covered by the spray fan, reducing frequent turning of the spray position. When there are two parallel candidate ridge chain backbones with the same length and equivalent passing frequency, the central controller preferentially selects the one that is adjacent to more pollution component cleaning positions at the end. The end is closer to the existing facilities, and the subsequent locking of the sink and the setting of the pollution extraction node are more direct, which can reduce the construction and temporary connection cost.

[0035] The central controller reads the ridge backbone and the list of exhaust components on the tunnel working condition grid map. The end of the ridge backbone is the position where the descending chain naturally stops at a relatively low position, usually closest to the direction of gravity convergence. Starting from the end, the facility alignment can be completed on the shortest end segment by backtracking one grid at a time, reducing subsequent path modification and temporary connection length. At each backtracking step, check the relationship between the current ridge grid cell and the position in the list of exhaust components: if there is an eight-way adjacent or co-located component position, confirm the position as a sink and stop backtracking. The reason for choosing "adjacent or co-located" is that when the drainage outlet, sump, pump pit and diversion channel valve maintain the shortest connection with the ridge end segment at the grid scale, the final convergence path of liquid and dust is the shortest, the pumping efficiency is higher, and the spray backflow and slurry accumulation in the end area are reduced. If backtracking along the entire ridge backbone does not neighbor or co-locate with any component position, the central controller searches for a grid cell within the ridge end and its neighborhood that meets two conditions: one is that the ground level is marked as a relatively low position, and two is that at least two descending chains converge at this cell. The first cell that meets the conditions is determined as the backup sink and is recorded as a temporary extraction point. Choosing a relatively low position allows the liquid-solid mixture after spray suppression to naturally stay in the lowest potential area, avoiding reverse slope backflow; choosing multiple chain convergence can concentrate the dust flow from multiple starting points, allowing extraction to be completed at one point, reducing equipment concurrency pressure. When multiple candidate sinks or multiple candidate backup sinks appear, the central controller prioritizes the one with a smaller Manhattan distance from the ridge end, and if they are still parallel, the one with a surrounding obstacle status marked as passable is chosen, and if they are still parallel, the one with more adjacent exhaust component positions is chosen. In this way, the requirements of minimizing end segment modification, higher construction accessibility, and subsequent connection flexibility can be met simultaneously.

[0036] The central controller selects one side of the outer edge of the dust cluster facing the backbone of the ridge chain as the laying reference of the spray induction zone. The specific method is: for each outer edge grid unit, calculate whether the shortest grid path to the backbone of the ridge chain is uninterrupted and the path direction is generally consistent, if it is satisfied, the outer edge unit is included in the spray induction zone. The benefit of selecting the side facing the ridge chain is that the momentum of the spray effect and the evaporation condensation effect are guided to the ridge chain, and the dust is pressed to the downward channel in the shortest transverse distance, reducing the probability of rebounding to the non-target side. The spray induction zone arranges the spray induction positions continuously along the outer edge, and the spacing follows the factory execution template of the integrated pollution discharge spray terminal group, so that adjacent spray fans have overlap at the grid level. The overlap can form a continuous pushing surface to avoid dust leakage at the gap. The central controller checks whether there is an obstacle between each spray induction position and the ridge chain during laying. If there is, mark the unit as blocked, if there is, move the spray induction position forward and backward by several grids without changing the outer edge selection side, until the shortest connected path without interruption is formed. When the spray induction zone changes direction along the outer edge, such as from longitudinal to oblique or transverse, the central controller sets an additional turning spray position at the outer edge grid unit where the turning occurs. In this way, the lateral gap of the fan coverage at the direction switching place can be compensated, and the inertial overflow of the dust outside the corner can be suppressed. The additional holding at the turning place can make the pushing surface continuous at the geometric discontinuity, reducing the "comb-like" residues caused by the fan edge effect. Near the end section of the ridge chain of the convergence or standby convergence, the central controller sets an end spray position, so that the spray fan points to the convergence or standby convergence. The role of the end spray position is to strengthen the directional suppression of the end section, form a complete pressure ladder from the outer edge of the dust cluster to the convergence, and promote the flow of liquid-solid mixture into the lowest potential point where the convergence is located, instead of forming accumulation in the end section area. End enhancement can also shorten the pre-pumping time and improve the instantaneous efficiency after pumping starts.

[0037] When the sink is adjacent to or co-located with a drain, sump, pump pit, or flume valve in the list of pollution components, the central controller directly designates the list of pollution components as the pollution extraction node. This way, the stable capacity of existing facilities and existing pipelines can be utilized, reducing the risk of new connections and temporary discharges, while facilitating maintenance and auditing. When a backup sink is used, the central controller sets a mobile pollution port in the adjacent grid direction of the backup sink and designates it as the pollution extraction node. The setting position must meet two conditions: first, there are no obstacles on the adjacent path marked as blocked units, which facilitates the entry of equipment and the layout of hoses; second, the Manhattan distance from the end of the ridge chain is as small as possible to shorten the extraction path and reduce the accumulation along the way. The mobile pollution port is connected to the extraction equipment through the standard interface of the integrated pollution spray terminal group, ensuring that the start and stop sequence can be directly dispatched by the coordinated control instruction set. When there are multiple pollution component list locations adjacent to each other, the central controller selects the one with a smaller Manhattan distance from the end of the ridge chain; if they are still parallel, the one with a larger peripheral passable area in the tunnel working condition grid map is selected to facilitate equipment layout and safety evacuation; if they are still parallel, the one with higher reliability in the historical maintenance record is selected. Through this path, the selection of the extraction node can take into account distance, accessibility, and operational stability without changing the algorithm structure.

[0038] Within the range of 5 to 10 grids in front of the end of the ridge chain, the sink search is prioritized, and if a hit is found, the sink is directly determined, and no further search is performed for more distant locations. This approach can speed up matching and make the most of existing facilities in the end near area, reducing the length of the modified end section. When the backup sink intersects with three or more descending chains, the central controller can set an additional end spray position on each of the two adjacent sides of the backup sink, forming a "clamping propulsion." Clamping propulsion can improve the suppression capacity of the end section in scenarios with a high proportion of large particle dust, preventing reverse diffusion upstream of the backup sink. When the outer edge length of the dust cluster exceeds 50 grids, the central controller divides the spray induction zone into several continuous segments and binds them in sequence with the phase-locked zone of the pollution extraction node. Segmenting can reduce the number of simultaneous spray starts, alleviate water supply and extraction concurrency pressure, while maintaining the continuity of the propulsion surface. Within a range of 2 to 3 grids around the sink or backup sink, the central controller prohibits the setting of new spray induction positions, only retaining the end spray position. This can avoid forming turbulent back eddies at the sink rim, ensuring that the liquid-solid mixture enters the drain, sump, or pump pit smoothly without accumulating at the rim.

[0039] The central controller pairs each spray induction position on the spray induction zone with a corresponding pollution extraction node on the ridge backbone direction on the roadway working grid map to form a plurality of phase-locked pairs. Each phase-locked pair adopts a fixed sequential interval of spray first and pollution second, and the sequential interval is derived from the factory execution template of the integrated pollution spray terminal group. Spray first can establish a continuous advancing surface between the spray induction zone and the ridge backbone, and first press the dust and the water vapor carried thereby to the low position along the slope direction; pollution second can be extracted synchronously after the dust is pressed to the low position to avoid backflow accumulation in the low position area. The phase-locked pairs are sequentially arranged in the direction from the dust cluster to the sink along the ridge backbone to obtain the advancing order of the phase-locked zone. The advancing order follows the strategy of nearest synthesis and short path priority: for two adjacent spray induction positions, if the corresponding pollution extraction nodes point to the same sink or are passable on the shortest connected path between adjacent sinks, then the two are synthesized into the same continuous step of the phase-locked zone. Nearest synthesis can reduce the water supply and extraction pulsation caused by repeated start and stop, and make the advancing surface more smooth in space and time. When two or more phase-locked zones need to occupy the same spray head, the same pollution pump or the same valve group in the same time window, the central controller determines the priority according to the number of high zone grid units of the dust cluster, the higher one goes first, and the lower one is delayed; if the number is the same, the one with shorter Manhattan distance from the end of the ridge to the pollution component is selected; if it is still the same, the phase-locked zone with a larger passable area is selected. Peak shifting execution avoids pressure drop or valve group misoperation caused by resource contention by delaying the start time of low priority, and ensures that high load areas are treated first, shortening the overall convergence time.

[0040] The central controller reviews the already scheduled phase-locked zone: if there is a passable grid unit on the outer edge of a dust cluster that is not covered by any spray induction position, a compensation spray induction position is added between the position and the ridge backbone, and a new phase-locked pair is formed with the nearest pollution extraction node and inserted into the phase-locked zone; if the compensation causes resource conflict with the existing advancing order, the peak shifting is re-performed according to the priority rules above.

[0041] The central controller generates a set of cooperative control instructions, which at least include a phase-locked band propulsion sequence, a spray nozzle start-stop sequence, a spray fan switching sequence, a blowdown pump start-stop sequence, a valve group switching sequence, and a staggered peak sequence. Each instruction is bound to a unique device address and a unique grid index, and records the identity information of the corresponding spray induction position or blowdown extraction node, ensuring that the execution object and the spatial position are one-to-one. For each phase-locked pair, the central controller encodes the interval between the spray first and the blowdown second as a relative time relationship, and concatenates it in the form of a step chain in the propulsion sequence. By using the relative time relationship, the order within the pair can be maintained when staggered peak adjustment occurs in different phase-locked bands, reducing the disturbance to the global timing. To avoid instruction loss or repeated execution, the set of cooperative control instructions sets a unique sequence number and a one-time execution identifier for each group of spray and extraction actions. The integrated blowdown and spray terminal group reports the post-execution state, and the central controller only enters the next step when it receives a receipt consistent with the current sequence number and indicating that the one-time execution identifier has been completed. This strategy can resist communication noise and repeated issuance, ensuring that the spray and extraction actions are not triggered multiple times. The central controller transmits the set of cooperative control instructions to the integrated blowdown and spray terminal group via the mine communication link, using a reliable transmission and acknowledgement retransmission mechanism. The purpose of the acknowledgement retransmission is that the short-time packet loss caused by the common multipath and occlusion in the roadway can be retransmitted according to the original sequence number within a limited number of times if no acknowledgement is received, ensuring the continuity of execution without introducing new concurrent conflicts. The set of cooperative control instructions is strictly executed according to the propulsion sequence and the staggered peak sequence at the integrated blowdown and spray terminal group side. When the valve group is not in place or the blowdown pump does not reach the stable speed state report, the central controller suspends the subsequent steps involving the same device address, and executes the unaffected phase-locked band first, thereby maintaining the continuity of the overall propulsion surface and avoiding backflow in the low area.

[0042] When the last step of the cooperative control instruction set receives a completion reply, the central controller immediately controls the dual-channel sensing assembly to collect a snapshot of the same working condition. Immediate collection can maximize the preservation of the true state after spraying and pumping, reducing secondary disturbances caused by wind flow changes. The central controller performs three checks on the snapshot of the same working condition: first, whether the high area of the dust cluster is suppressed to a medium or low area; second, whether a new relatively low outside expansion appears near the end of the ridge backbone; third, whether a continuous un-pumped retention zone appears around the outlet or backup outlet. The reason for selecting these three is that they correspond to whether the advance is effective, whether the slope path is stable, and whether the end pumping is smooth, which can directly reflect whether the phase coordination of spraying first and pumping later meets the expectations. If all three checks are met, the central controller will archive this phase lock zone and the advance sequence as a reusable template on site; if any one is not met, the central controller will recalculate the local adjustment of the phase lock zone based on the same working condition snapshot, with the adjustment range limited to adding or deleting individual spray induction positions, fine-tuning the advance sequence, or replacing the nearest pumping extraction node, and immediately issue a set of cooperative control instructions containing only the modified steps for execution once. Limiting the adjustment range can avoid new disturbances to the converged area and shorten the execution time.

[0043] For a spray induction zone longer than 50 grids, the central controller divides it into several segments, each segment independently forms a phase lock zone with the pumping extraction node, and staggered by segment on a global level. The segmentation method can control the number of simultaneous spraying and simultaneous pumping, reduce the instantaneous peak of water supply and pumping, while maintaining the continuity of the advance. In the last segment near the outlet or backup outlet, the central controller sets a fixed time window for the end spray position and the corresponding pumping extraction node, and prohibits other phase lock zones from entering the last segment area within the time window. The time window makes the liquid-solid mixture flow at the end of the low position more single, reducing backflow and resuspension. When the snapshot of the same working condition shows that a certain dust cluster has significantly shrunk, the central controller lowers the priority of the corresponding phase lock zone in the subsequent steps, allowing resources to be allocated to larger dust clusters. Dynamic updating can accelerate overall convergence and avoid continued investment in areas that have already approached completion.

[0044] As shown in Figure 2 The dust cluster analysis schematic diagram of the roadway working condition grid map of the present application details the grid working condition map generated by fusing the dust image and the ground height image obtained based on the dual-channel sensing assembly. The map takes the roadway reference line as the longitudinal reference, divides equidistant grids according to the effective coverage width of a single spray nozzle, forms a 15x12 grid matrix, and each grid unit has three attributes of dust level annotation, ground height annotation, and obstacle state annotation. In terms of dust level annotation, the central controller calls the built-in thresholding grading function to divide the dust image into high, medium, and low areas (dark gray, >150 mg / m 3), middle zone (medium gray, 50-150 mg / m 3 ), low zone (light gray, 10-50 mg / m 3 ), and clean zone (white, <10 mg / m 3 ). Two major dust clusters are identified in the figure: dust cluster A is located in the area of grid (4, 1)-(6, 2) and contains 18 high-zone grid cells; dust cluster B is located in the area of grid (11, 1)-(13, 2) and contains 12 high-zone grid cells. Based on the octant adjacency rule, the system collects all the descending adjacencies from the passable grid cells on the outer edge of each dust cluster, forming a descending candidate set. By the strategy of prioritizing the relatively low grid cells and secondarily the relatively middle grid cells, multiple descending chains with clear start and end are constructed. Three descending chains for dust cluster A and three descending chains for dust cluster B are shown in the figure, in which the most frequently-passed connected path is selected as the backbone of the ridge chain, with the length of 260 mm and 220 mm, respectively. The system implements the minimum-span bypass strategy at the single-grid gap on the backbone of the ridge chain caused by the blockage (obstacle represented by black grid). The path is corrected by the adjacent relatively middle grid cells. Tracing back along the ridge chain from the end, the sink is preferentially locked, which is adjacent to or in the same position as the list of pollution removal components. The sink of dust cluster A is the drainage ditch, and the sink of dust cluster B is the water collection pit. The spray induction belt is laid on the side of the outer edge of the dust cluster facing the ridge chain, and the spray induction positions (white circle markers) are sequentially specified according to the execution template interval set by the terminal group. The phase-locked belt boundary (dashed line box) indicates the control area of the spray first and the pollution removal second, which embodies the system's cooperative control strategy.

[0045] As Figure 3As shown, the integrated terminal group of the present application cooperatively performs the timing chart to show the cooperative control process of the system based on priority sorting and staggered execution strategy. The timing chart covers the complete execution cycle of the dust cluster A, B, C three phase-locked zones, with a time span of 75 seconds, embodying the priority scheduling mechanism of "the higher first, the lower delayed". Dust cluster A, as the highest priority unit with the most number of high zone grids (18), starts execution at 0 seconds. Its spray induction stage contains 6 serialized spray positions (A1-A6), which are started in turn according to a 2-second phase difference, with each spray position lasting for 4 seconds. The staggered start mode of the spray induction position ensures the continuous pushing effect of the dust along the ridge chain. At the 20th second, the pollution extraction A is started, embodying the phase-locked mechanism of 5-second delay, and lasts for 10 seconds to complete the pollution removal work in this area. Dust cluster B has 12 high zone grids, with priority lower than dust cluster A. The system remains in a waiting state during 0-30 seconds to avoid resource conflicts with dust cluster A. Execution starts at the 30th second, embodying the 30-second staggered interval scheduling strategy. Its spray induction stage contains 4 serialized positions (B1-B4), which are also started in turn according to a 2-second phase difference. The pollution extraction B is started at the 40th second and lasts for 8 seconds to complete the work. Dust cluster C has the least number of high zone grids (8) and the lowest priority. The system remains in a waiting state during 0-45 seconds to ensure that the first two dust clusters are completely executed before starting. Its spray induction stage contains 3 positions (C1-C3), and the pollution extraction C is started at the 53rd second and lasts for 6 seconds. The abnormal recovery area (60-75 seconds) shows the fault tolerance mechanism of the system. When an execution anomaly is detected, the system automatically enables the backup sink and executes the minimum bypass strategy to ensure the high reliability of the system. The whole timing chart embodies the system's realization of optimal resource allocation and maximum execution efficiency while ensuring dust reduction effect.

[0046] The present application is not limited to the foregoing specific embodiments. The present application extends to any novel one, or any novel combination, of the characteristics disclosed in this specification, as well as to any novel method or process disclosed.

Claims

1. An intelligent integrated automatic pollution discharge and spray dust reduction system for a coal mine tunnel, characterized in that, The system comprises a double-channel sensing component, a central controller, a mine communication link and an integrated pollution discharge spray terminal group; the central controller is configured to: acquire dust images and ground height images at the same time through the double-channel sensing component; generate a roadway working condition grid map, complete dust level labeling and ground height labeling, extract dust clusters and transition zones, and load a pollution discharge component list; based on the roadway working condition grid map and the pollution discharge component list, construct a descending chain from the outer edge of the dust cluster according to the eight-neighbor rule, select the ridge chain backbone according to the number of passes, and implement the minimum bypass for single grid gaps caused by blockage; lock the sink adjacent to or in the same position as the pollution discharge component list from the end to the front along the ridge chain, and determine a standby sink at a relatively low position and a grid unit where multiple chains intersect; lay a spray induction zone outside the dust cluster, set a turning spray position and an end spray position; determine corresponding pollution discharge extraction nodes; form a phase-locked zone with spray first and pollution second, and execute in priority according to the priority; generate a cooperative control instruction set and issue it to the integrated pollution discharge spray terminal group through the mine communication link for execution; and after the execution of the cooperative control instruction set, control the double-channel sensing component to acquire a snapshot of the same working condition for acceptance.

2. The intelligent integrated automatic pollution-removing and spraying dust-settling system for coal mine tunnels according to claim 1, characterized in that, The double-channel sensing component comprises a dust imaging channel and a ground depth channel, which acquire a single snapshot at the same time; the dust imaging channel is a dust camera installed on the roadway roof or sidewall, and its output is a single frame of dust image; the central controller calls its built-in thresholding grading function to divide the dust image into three categories: high, medium and low, and obtains a dust level labeling map; the ground depth channel is a depth scanner facing the roadway floor, and its output is a single frame of ground height image; the central controller performs built-in plane correction and attitude compensation to align the ground height image to a unified coordinate, and generates a ground height labeling map, in which each position is labeled as relatively high, relatively medium or relatively low.

3. The intelligent integrated automatic pollution-removing and spraying dust-settling system for coal mine tunnels according to claim 2, characterized in that, The pollution discharge component list is preloaded in the static engineering table of the central controller during equipment installation and debugging, including the fixed positions of drainage outlets, sump pits, pump pits and diversion groove valves; the central controller takes the roadway reference line as the longitudinal reference, divides equidistant grids according to the effective coverage width of a single spray nozzle, and generates a roadway working condition grid map; project the dust level labeling map and the ground height labeling map onto the roadway working condition grid map, so that each grid unit has dust level labeling, ground height labeling and obstacle state labeling; if the ground depth channel identifies a protruding obstacle, the obstacle state labeling of the grid unit is blocked, otherwise it is passable.

4. The intelligent integrated automatic pollution-removing and spraying dust-settling system for coal mine tunnels according to claim 3, characterized in that, The central controller defines a dust cluster on the roadway working condition grid map as a set of grid cells adjacent to each other and marked as high dust level, and binds the adjacent medium dust level grid cells to the dust cluster. For any passable grid cell, if any adjacent grid cell has a lower ground level mark, the adjacent grid cell is marked as a descending neighbor of the passable grid cell. The adjacent relationship is an eight-directional neighbor centered on the grid cell. For each passable grid cell on the outer edge of the dust cluster, collect all the descending neighbors to form a descending candidate set of the grid cell. If there is no descending neighbor, the grid cell is marked as a local low-level grid cell.

5. The intelligent integrated automatic pollution-removing and spraying dust-settling system for coal mine tunnels according to claim 4, characterized in that, The process of obtaining a plurality of start and end explicit descending chains from each dust cluster by the central controller includes: selecting all high dust level grid cells on the outer edge of each dust cluster as a set of descending chain starting points; starting from any descending chain starting point, extending by grid in the following order: if there is a relatively low-level grid cell in the descending candidate set, preferentially enter the one closest to the direction of the starting point; if there are only relatively medium-level grid cells, enter any one with the smallest change in the current forward direction; if a block is encountered in front, terminate the branch at the block; when a grid cell has two or more descending neighbors, generate parallel branches to continue growing respectively; when entering a local low-level grid cell and none of its adjacent grid cells have a lower mark, terminate the branch.

6. The intelligent integrated automatic pollution-removing and spraying dust-settling system for coal mine tunnels according to claim 5, characterized in that, The central controller counts the number of passes of each grid cell by all descending chains in the same dust cluster, and defines the path with the highest number of passes as the backbone of the ridge chain of the dust cluster. If there are multiple parallel paths, the one with the shorter total length is selected as the backbone of the ridge chain. For individual grid gaps on the backbone of the ridge chain caused by blocks, a minimum span bypass is allowed through the relatively medium-level grid cells adjacent to the gap, and the bypass grid cells are integrated into the ridge chain. From the end of the ridge chain, trace back to find a grid cell adjacent to or co-located with any position in the list of pollution removal components. The first hit position is defined as the sink of the dust cluster. If there are multiple candidates, the one with the smaller Manhattan distance from the end of the ridge chain is selected. If none of the candidates are hit, select a relatively low-level grid cell that intersects with two or more descending chains in the neighborhood of the end of the ridge chain as a backup sink, and record the grid cell as a temporary extraction point.

7. The intelligent integrated automatic pollution-removing and spraying dust-settling system for coal mine tunnels according to claim 6, characterized in that, The side of the dust cluster outer edge facing the ridge chain is used as the reference for laying the spray induction belt. On the spray induction belt, a plurality of spray induction positions are specified in the interval order of the execution template set by the terminal group. The fan of each spray induction position faces the ridge chain, and an additional turning spray position is set at the turning grid cell to suppress lateral overflow. At the end segment of the ridge chain near the sink, an end spray position is set to direct the dust along the ridge chain to the sink.

8. The intelligent integrated automatic pollution-removing spraying dust-settling system for coal mine tunnels according to claim 7, characterized in that, If the sink corresponds to a fixed facility in the list of pollution removal components, the facility position is specified as a pollution extraction node. If a backup sink is used, a mobile pollution port is set in the adjacent grid direction of the position, and it is specified as a pollution extraction node. The connection relationship is completed through the standard interface of the terminal group.

9. The intelligent integrated automatic pollution-removing spraying dust-settling system for coal mine tunnels according to claim 8, characterized in that, The central controller binds the spray induction zone and the exhaust extraction node in pairs to form a phase-locked zone with the spray leading and the exhaust following; the advancing direction is along the ridge chain from the dust cluster to the sink; when two or more dust clusters need to occupy the same spray nozzle or the same valve group in the same time window, the number of high-zone grid units of the dust cluster is used as the priority basis, with the higher one leading and the lower one following; the following result is written into the staggered sequence of the cooperative control instruction set; if there are passable grid units on the outer edge of the dust cluster that are not covered by any spray induction position, a compensation spray position is automatically set between the grid unit and the ridge chain and incorporated into the current phase-locked zone; the central controller writes the advancing sequence of the ridge chain, sink, spray induction zone, exhaust extraction node, and phase-locked zone corresponding to each dust cluster into the cooperative control instruction set and issues it to the integrated exhaust spray terminal group through the mine communication link for execution, so that the dust is continuously pushed along the ridge chain to the sink and is synchronously extracted to complete dust reduction and exhaust.

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