Control system for coal transportation equipment on top coal working face

Abstract

The invention belongs to the technical field of coal transportation control, and particularly discloses a top coal working face coal transportation equipment control system which comprises a coal flow distribution scanning module, a directional migration control module, a cooperative regulation and control module and an anti-rebound maintaining module which are sequentially coupled and connected. A complete control link from coal flow state sensing to migration regulation and control execution to dynamic stability maintenance is formed, and local accumulation upheaval areas and sunken areas formed in the scraper conveying process are identified based on coal flow section three-dimensional point cloud data obtained on a scraper conveyor in real time. In combination with a piezoelectric ceramic actuator array arranged at the bottom of the conveyor, directional stress traveling waves pointing to a concave area from a raised area are excited in a target area through phase difference control, local active migration regulation and control of coal particles are achieved, the method can accurately act on areas with uneven coal flow, interference to other areas is reduced, and the coal conveying efficiency is improved. And aggravation of imbalance of coal flow distribution is effectively inhibited.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal transportation control, and specifically discloses a control system for coal transportation equipment on a top coal working face. Background Art

[0002] As energy demand continues to grow, coal, as a key fossil fuel, plays an indispensable role in modern industry. Against this backdrop, top-coal face mining has become the mainstream method in coal mining, offering advantages over traditional layered mining, such as reduced tunneling, lower engineering investment, and reduced maintenance costs.

[0003] After being mined underground, coal must be transported to surface processing plants or loading points via a continuous transportation system consisting of scraper conveyors, transfer machines, and belt conveyors. The scraper conveyor, a key piece of equipment that directly receives the mined coal at the working face, is typically located at the bottom of the working face, transporting the coal cut by the shearer along the working face to the transfer machine.

[0004] During actual operation, coal particles formed by shearer cutting are influenced by a variety of factors, including the physical properties of the coal, cutting speed, and cutting depth. These particles tend to stick together, forming lumps or agglomerates, leading to uneven coal flow on the scraper conveyor. This uneven flow can cause load fluctuations on the scraper chain, leading to periodic overloads. This not only accelerates wear on transmission components but can also cause fatigue damage to key structural components, increasing failure rates and maintenance frequency, thus impacting overall production efficiency and system stability.

[0005] To alleviate the above problems, the industry often uses two typical means of intervention: 1. Configure a crushing device: Install a crusher behind the coal mining machine to perform preliminary crushing of large pieces of coal to improve the fluidity of the coal flow.

[0006] However, this method can only effectively process larger-sized coal blocks. It is difficult to dissociate small particles of coal that have already adhered, and it cannot fundamentally solve the problem of uneven coal flow distribution.

[0007] 2. Adjust the inclination angle of the scraper conveyor: By moderately raising one end of the scraper conveyor, the flow performance of the coal can be enhanced by using gravity.

[0008] While this method can increase the material's descent speed to a certain extent, the frictional resistance of coal of varying particle size, moisture content, and form on the inclined surface varies. This causes dry, fine coal to slide quickly while wet, sticky coal accumulates, further exacerbating the uneven distribution of coal flow. Furthermore, the mechanical structure and installation conditions of the scraper conveyor limit its tilt adjustment range. Excessive tilt can lead to unstable equipment operation and unbalanced support structure forces, creating new safety hazards and increasing maintenance burdens.

[0009] In summary, the above-mentioned traditional control methods have a certain auxiliary role in dealing with the problem of uneven coal flow, but cannot achieve effective control of the uneven state of coal flow. Summary of the Invention

[0010] In view of this, the present invention aims to propose a control system for coal transportation equipment at the top coal working face, which embeds piezoelectric ceramic actuators in key areas at the bottom of the scraper conveyor to provide directional pulse vibration excitation for areas with uneven coal flow, thereby destroying the adhesion between coal particles and achieving effective control of the uneven state of coal flow.

[0011] The purpose of the present invention can be achieved through the following technical solutions: A coal transportation equipment control system for a top coal working face, comprising: a coal flow distribution scanning module: using an infrared laser grid scanner to capture the three-dimensional point cloud data of the coal flow cross section on the scraper conveyor in real time, identifying the coordinates of the accumulation depression area and the uplift area based on the spatial density distribution of the point cloud, and generating a vector map of the uneven area with spatial coordinates.

[0012] Directional migration control module: piezoelectric ceramic array actuators are arranged in partitions at the bottom of the scraper trough, and the actuator groups in the stacking uplift area and the adjacent transition area are activated according to the vector map coordinates. Through phase difference control, a directional stress traveling wave is formed on the surface of the trough from the uplift area to the depression area.

[0013] Collaborative control module: The coal particle migration direction is captured in real time by a high-speed camera, and the coal feeding speed at the front end of the scraper is monitored simultaneously by a laser rangefinder. The scraper chain speed adjustment instructions are collaboratively output according to the coal particle migration direction and the coal feeding speed at the front end of the scraper.

[0014] Anti-rebound maintenance module: After the directional stress traveling wave action ends, micro-pulse vibration with decreasing voltage steps is started in the accumulation uplift area, and the vibration data of coal particles in the accumulation depression area is collected in real time through the vibration sensor, and the micro-pulse output state is dynamically adjusted according to the vibration changes.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention identifies the local accumulation ridges and depressions formed during scraper conveying based on the real-time acquired three-dimensional point cloud data of the coal flow cross section, and combines it with the piezoelectric ceramic actuator array arranged at the bottom of the conveyor to excite directional stress traveling waves from the ridges to the depressions in the target area through phase difference control, thereby realizing local active migration control of coal particles, accurately acting on areas with uneven coal flow, reducing interference with other areas, and effectively suppressing the aggravation of coal flow distribution imbalance. It has the technical advantages of fast response, strong adaptability, and high control accuracy.

[0016] 2. During the implementation of local coal particle migration control, the present invention synchronously monitors the coal particle migration direction and the coal feed speed at the front end of the scraper, and coordinately adjusts the scraper chain speed accordingly to ensure that the migration process matches the conveying rhythm. It can improve the accuracy of coal particle migration control without disturbing the front-end coal flow accumulation state, effectively avoid the aggravation of coal flow accumulation or conveying interruption caused by chain speed mismatch, and enhance the continuity and stability of system operation.

[0017] 3. After completing the local active migration of coal particles, the present invention further starts micro-pulse vibration excitation with a step-by-step decreasing voltage in the accumulation uplift area, suppressing the rebound tendency of coal particles due to inertia or gravity through gradually weakening disturbance, effectively maintaining the stable state of coal flow after migration, preventing local secondary accumulation, and improving the continuity and distribution uniformity of the scraper conveying process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 Schematic diagram of the system composition of the present invention.

[0020] Figure 2 This is an implementation flow chart of the collaborative output of scraper chain speed adjustment instructions in the present invention.

[0021] Figure 3 This is a flowchart for implementing the method of dynamically adjusting the micro-pulse output state according to vibration changes in the present invention. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] See also Figure 1 As shown, the present invention proposes a control system for coal transportation equipment in a top coal working face, comprising a coal flow distribution scanning module, a directional migration control module, a coordinated control module and an anti-rebound maintenance module coupled in sequence, forming a complete control link from coal flow state perception to migration control execution to dynamic stability maintenance.

[0024] The coal flow distribution scanning module uses an infrared laser grid scanner to capture the three-dimensional point cloud data of the coal flow cross section on the scraper conveyor in real time, identifies the coordinates of the accumulation depression area and the uplift area based on the spatial density distribution of the point cloud, and generates a vector map of the uneven area with spatial coordinates.

[0025] Preferably, the specific implementation process of the above module is as follows: an infrared laser emitter array is evenly arranged at a set interval on the longitudinal axis of the scraper conveyor, and a high-resolution optical imaging device is configured on the opposite side of the scraper conveyor.

[0026] An infrared laser emitter array is used to emit parallel laser beams to penetrate the coal flow layer, and the scattered light spot image generated by the laser beam on the surface of the coal particles is captured by optical imaging equipment, thereby constructing the three-dimensional spatial point cloud data of the coal flow cross section.

[0027] It's important to understand that the roughness and non-uniformity of coal particle surfaces produce diffuse reflection and localized strong scattering when irradiated by infrared laser beams. High-resolution optical imaging equipment captures these scattered light spot images and extracts their position information. Based on the known laser emission angle, camera position, and the coordinates of the light spot in the image, triangulation is used to calculate the spatial height information of each point on the coal particle surface, thereby generating three-dimensional point cloud data of the coal flow cross section.

[0028] The above three-dimensional spatial point cloud data accurately reflects the three-dimensional morphological characteristics of the coal flow cross section, providing key basic data support for the subsequent identification of accumulation uplift areas and depression areas.

[0029] In particular, the method of using infrared laser technology to construct three-dimensional spatial point cloud data of coal flow cross-sections has significant advantages. On the one hand, it uses non-contact measurement methods to ensure accurate data collection without interfering with the normal operation of the coal flow. On the other hand, infrared laser has strong penetrating ability, and its wavelength range determines that it is less affected by ambient light interference. Therefore, it can maintain stable performance even under complex lighting conditions.

[0030] The obtained three-dimensional spatial coordinate point cloud data is statistically analyzed using a sliding window to calculate the distribution density of the point cloud data within a unit area, and a spatial density distribution map of the coal flow cross section is constructed.

[0031] According to the preset density upper limit threshold and density lower limit threshold, the uplift area where the coal flow distribution density is higher than the density upper limit threshold and the depression area where the density is lower than the density lower limit threshold are identified respectively, and their corresponding spatial coordinate ranges are marked.

[0032] It should be noted that the correlation between coal flow distribution density and accumulation morphology is based on the fact that the distribution density of point cloud data per unit area can effectively reflect the internal structure of the coal flow and the density of the particle accumulation. When the coal flow density in a certain area exceeds the preset upper density threshold, it indicates that the coal accumulation in that area is too dense and there is local uplift, which is determined to be an uplifted area. Conversely, when the coal flow density in a certain area is lower than the preset lower density threshold, it indicates that the coal distribution in that area is sparse, which is determined to be an accumulation depression. This method achieves quantitative identification of the coal flow distribution state through density characteristics, providing accurate data support for subsequent control strategies.

[0033] It should be added that the upper and lower density thresholds set above are used to define the normal accumulation state range of coal flow during transportation, and are the key criteria for identifying whether the coal flow distribution is uniform. However, setting only a single density threshold to judge the coal flow state can usually only distinguish between normal and abnormal states. For example, a fixed density threshold is set, and a value above this threshold is considered to be excessive accumulation, and a value below this threshold is considered to be insufficient distribution. However, the state changes of coal flow in actual working conditions are often more complex, and a single threshold is difficult to fully reflect these changes. The use of a dual threshold mechanism can more accurately distinguish between local excessive accumulation and insufficient distribution of coal flow, thereby improving the recognition accuracy and the pertinence of the control strategy.

[0034] Specifically, the upper and lower thresholds can be set based on statistical analysis of historical operating data, using the average value and standard deviation of the coal flow density under stable system conditions as a reference. For example, the average density value plus one standard deviation can be used as the upper density threshold, while the average density value minus one standard deviation can be used as the lower density threshold.

[0035] The coordinate information of the accumulation uplift area and the accumulation depression area is converted into a vector map of the uneven area with spatial coordinates, and is refreshed and updated at a preset time period.

[0036] The directional migration control module arranges piezoelectric ceramic array actuators in partitions at the bottom of the scraper trough, activates the actuator groups in the stacking ridge area and the adjacent transition area according to the vector map coordinates, and forms a directional stress traveling wave on the trough surface from the ridge area to the depression area through phase difference control.

[0037] In a manner that can be implemented by the above solution, piezoelectric ceramic array actuators are arranged in partitions at the bottom of the scraper trough. Refer to the following process: obtain the geometric dimensions of the scraper conveyor trough body, and divide the bottom surface of the scraper trough into partitions based on the effective action area of a single piezoelectric ceramic actuator.

[0038] Piezoelectric ceramic actuators are embedded in the bottom surface of the groove corresponding to each partition. Each actuator is independently connected to a drive circuit with voltage regulation and phase control functions. This ensures that each actuator can effectively excite directional stress waves within its set area and act on the coal flow layer.

[0039] In a further achievable manner of the above-mentioned scheme, the actuator groups of the stacking ridge area and the adjacent transition area are activated according to the coordinates of the vector map, and a directional stress traveling wave pointing from the ridge area to the depression area is formed on the surface of the trough body through phase difference control. The specific contents are as follows: According to the stacking ridge area and depression area marked in the vector map of the uneven area, the two are paired based on the principle of spatial proximity to determine the stacking depression area paired with each stacking ridge area.

[0040] It should be understood that the above-mentioned pairing of uplift areas and depression areas based on the principle of spatial proximity, that is, matching each uplift area with the depression area closest to it in spatial position as the target area for coal migration, can achieve directional regulation within a local range, avoid redundant energy consumption and control logic conflicts caused by excitation across too many regions, thereby improving the system response efficiency and energy utilization rate, and ensuring the orderliness of the regulation process and the accuracy of the actuator action.

[0041] Based on the spatial position relationship between the raised area and the depressed area, the path direction between the two is extracted, and the area passing from the stacked raised area to the depressed area is defined as the adjacent transition area, thereby activating the piezoelectric ceramic actuator group embedded under the stacked raised area and the adjacent transition area.

[0042] A sinusoidal excitation voltage signal with consistent frequency and adjustable amplitude is applied to the actuator group corresponding to the ridge area, while a cosine wave excitation voltage signal with the same frequency but a phase lag of π / 2 is applied to the actuator group corresponding to the adjacent transition area.

[0043] The phase difference between the sine wave and the cosine wave is superimposed to generate a surface wave that propagates in one direction from the raised area to the depressed area.

[0044] It needs to be explained that the principle of implementing directional migration of coal flow by arranging piezoelectric ceramic actuators in partitions at the bottom of the scraper conveyor trough is that the piezoelectric ceramic material will undergo periodic deformation when an AC voltage is applied, thereby exciting elastic vibration waves on the surface of the trough. The elastic vibration waves are used to drive the ceramic pieces to produce high-frequency micro-vibrations. On the one hand, it can break up the coal blocks adhered together in the uneven area. On the other hand, when multiple piezoelectric ceramic actuators are arranged in a certain spatial order and excitation signals with a fixed phase difference are applied to each other, a unidirectional elastic traveling wave can be synthesized on the surface of the structure. The coal particles are subjected to a periodic driving force under the action of the directional traveling wave. When the driving force exceeds the friction and adhesion force between the particles, the particles will jump along the propagation direction of the traveling wave. This migration method can achieve active regulation of the coal flow distribution without the need for a mechanical disturbance device, prompting the directional migration of coal particles from the stacked raised area to the depressed area, thereby improving the problem of uneven coal flow distribution.

[0045] It's worth noting that simply exciting the heave zone alone makes it difficult to establish a continuous, stable wave propagation path. Therefore, introducing adjacent transition zones as cooperative excitation units essentially acts as a waveform relay. By setting a phase difference, the spatial continuity and propagation directionality of the vibration wave are enhanced, significantly improving the controllability and efficiency of coal particle migration.

[0046] The distance between the stacking ridge and depression areas is obtained based on their locations, and the excitation voltage amplitude of the stacking ridge area is determined in combination with the preset unit distance excitation voltage amplitude. At the same time, an excitation voltage is configured for the actuator in the adjacent transition area, and its value is set to be attenuated relative to the excitation voltage of the ridge area according to a preset ratio.

[0047] The key point to understand when applying this approach is that, in achieving directional coal particle transport, relying solely on phase difference control between piezoelectric ceramic actuators is insufficient to ensure effective coal transport. An appropriate excitation voltage is also required, providing sufficient vibration energy to drive the coal particles to overcome frictional resistance and complete the transport process.

[0048] Because elastic waves propagate through structures with energy attenuation, their intensity gradually decreases with increasing propagation distance. Therefore, the excitation voltage for the piezoelectric ceramic actuator corresponding to the underlying ridge should be set based on the geometric distance between the ridge and the depression, rather than the distance between the ridge and the transition zone. This is because, although the coal initially migrates from the ridge to the adjacent transition zone, the ultimate goal of the entire migration process is to achieve complete material transfer from the ridge to the depression. Therefore, the overall migration path length is used as the basis for voltage regulation to ensure sufficient vibration energy is maintained throughout the migration path, allowing the coal particles to stably migrate to the final target area.

[0049] As a specific embodiment of the above scheme, the preset unit distance excitation voltage amplitude can be determined by an experimental calibration method, which specifically includes the following steps: first, based on the current structural parameters and operating status of the scraper conveyor, a standardized test platform is constructed in the laboratory or under simulated working conditions.

[0050] Multiple standard migration distances such as 0.5m, 1.0m, 1.5m, etc. are set on the platform to cover the typical coal flow migration path range.

[0051] Subsequently, under the same coal quality conditions, the excitation voltage applied to the piezoelectric ceramic actuator was gradually increased, and the response state of the coal particles was monitored simultaneously.

[0052] The critical excitation voltage value at which coal particles begin to migrate in a directional manner is recorded at different migration distances.

[0053] Finally, based on the collected voltage-distance data, the least squares method or other fitting algorithms are used to establish a functional relationship curve between the excitation voltage and the migration distance, thereby extracting the excitation voltage value required per unit distance, providing a quantitative basis for the voltage allocation strategy in the subsequent actual control process.

[0054] Furthermore, the excitation voltage applied by the piezoelectric ceramic actuators deployed in adjacent transition zones is set to attenuate by a preset ratio relative to the excitation voltage in the accumulation and uplift zones, thereby achieving hierarchical control of the excitation energy. In this strategy, the accumulation and uplift zones are configured with a higher excitation voltage to provide sufficient initial driving force, prompting coal particles to break free from their stationary state and acquire kinetic energy for migration. The primary function of the transition zone is to receive the coal flow transferred from the uplift zone and smoothly guide it to the final target depression zone, thus requiring relatively low excitation energy. The excitation voltage applied in the transition zone is typically set to a certain proportion of the excitation voltage in the accumulation and uplift zones. This proportion can be determined simultaneously during the experimental calibration process based on the excitation voltage amplitude per unit distance, and is exemplarily set at 40% to maintain the continuity of the vibration waveform while avoiding excessive disturbance of the coal flow in this area. Applying an excessively high excitation voltage in the transition zone can lead to abnormal acceleration of localized coal particles, disrupting the consistency of the migration direction, and even inducing reverse migration or localized hollowing, affecting the overall control effect.

[0055] The collaborative control module uses a high-speed camera to capture the coal particle migration direction in real time, and simultaneously uses a laser rangefinder to monitor the coal feeding speed at the front end of the scraper, and collaboratively outputs scraper chain speed adjustment instructions based on the coal particle migration direction and the coal feeding speed at the front end of the scraper.

[0056] Preferably, the migration direction of coal particles is captured in real time by a high-speed camera as follows: the dynamic movement state of coal particles in the accumulation uplift area is continuously captured by a high-speed camera installed above the scraper trough, and a high frame rate image sequence of the coal flow under the excitation of the piezoelectric ceramic actuator is obtained.

[0057] The spatial position information of coal particles in each frame of the collected continuous frame images is identified in turn, and the motion vector of the coal particles is obtained based on the displacement relationship between adjacent frames. Therefore, the coal particle migration path in the accumulation uplift area is established by temporal analysis of the coal particle position changes in multiple frame images, and then the coal particle migration direction is extracted.

[0058] It should be noted that the technical basis for using high-speed cameras to capture the migration direction of coal particles is that under the excitation of piezoelectric ceramics, coal particles may undergo jumping migration behavior with transient characteristics. In order to accurately identify the motion trajectory and direction characteristics in this process, dynamic observation is required with the help of visual acquisition methods with high time resolution; and due to its non-contact measurement characteristics, high-speed cameras can achieve high-precision recording and analysis of particle-level migration behavior without interfering with the natural movement state of the coal flow.

[0059] Further preferably, the implementation of using a laser rangefinder to monitor the coal feed speed at the front end of the scraper conveyor is as follows: during the operation of the scraper conveyor, a laser rangefinder deployed above the scraper trough is used to make its light beam vertically cover the coal flow accumulation area at the feed end of the scraper conveyor.

[0060] A laser rangefinder is used to continuously emit laser pulses at a set frequency and receive the echo signal reflected from the coal surface at the feed end. The distance between the top of the coal seam at the feed end of the scraper and the sensor installation reference surface is calculated by the flight time.

[0061] It should be pointed out that the flight time mentioned above is the time difference between the emission and reception of the laser pulse. The distance between the top of the coal seam at the feed end of the scraper conveyor and the sensor installation reference plane is obtained by dividing the flight time by 2 and multiplying it by the speed of light.

[0062] The actual coal accumulation height is calculated based on the calculated distance value and the scraper trough height.

[0063] Because the laser rangefinder is mounted above the scraper conveyor trough, the distance it measures is the vertical distance between the sensor's emitting surface and the top of the coal seam at the scraper conveyor's feed end. This measurement path includes the height structural dimensions of the scraper trough itself, representing the fixed distance between the sensor's reference surface and the bottom of the trough. Therefore, the actual coal accumulation height must be calculated using geometric relationships: subtracting the known trough structural height from the total distance measured by the laser rangefinder. The resulting difference is the actual coal accumulation height within the trough.

[0064] The coal feeding rate is obtained by calculating the change in coal pile height at adjacent monitoring moments.

[0065] It should be understood that the principle of obtaining the coal feed rate by calculating the change in coal pile height at adjacent monitoring moments is based on the material accumulation rate in continuous time intervals. The production of coal at the front end of the scraper conveyor is continuous, which means that in any given time period, the coal flow will continue to enter the scraper conveyor and form a certain pile height at the feed end. In a short period of time, the feed rate of the coal flow can be considered to be constant. Therefore, between two adjacent time points, the height of the coal seam will change. The coal feed rate can be defined as the rate of change of the coal pile height per unit time.

[0066] To further quantify the material conveying speed during the coal feeding process, the measured change in coal pile height can be converted into a change in volume. Specifically, if the load-bearing length and width of the scraper conveyor feed end are known, the height change can be converted into a volume change, and combined with the time interval to more comprehensively describe the coal feeding speed.

[0067] It should be noted that the advantages of determining coal feed rate based on coal seam height are: coal seam height is easy to measure and has a clear physical meaning. It does not rely on the specific physical parameters of coal particles, and the feed trend can be reflected solely through changes in height, which has good versatility and adaptability to working conditions. Furthermore, combined with laser ranging technology with a set frequency, it can achieve continuous, real-time monitoring of coal seam height, thereby quickly responding to coal flow fluctuations, and has high measurement efficiency and dynamic response capabilities.

[0068] Further, see Figure 2 As shown, the scraper chain speed adjustment instruction is output in coordination with the coal particle migration direction and the coal feeding speed at the front end of the scraper as follows: the path direction extracted based on the spatial position relationship between the raised area and the depressed area is used as the required migration direction.

[0069] The coal particle migration direction is compared with the required migration direction to obtain the migration direction deviation angle, and then compared with the set allowable deviation threshold.

[0070] For example, the allowable deviation threshold can be calibrated by conducting a coal flow migration characteristic test on the aforementioned standard test platform.

[0071] a) If the migration direction deviation angle meets the allowable deviation threshold, the pre-established mapping relationship between the coal feed speed and the ideal scraper chain speed is called, and the real-time monitored coal feed speed is substituted into the mapping relationship as an input parameter to calculate the corresponding scraper chain speed target value, and then the scraper chain operating speed is adjusted accordingly.

[0072] Applicable to the above operation, when the migration direction deviation angle meets the allowable deviation threshold, it indicates that the migration effect driven by the directional stress traveling wave is good and the coal flow migration direction is consistent with the set path. At this time, to avoid coal accumulation or conveying lag at the scraper conveyor feed end, it is necessary to maintain a dynamic balance between coal flow input and output. Based on this requirement, it is necessary to adjust the scraper chain speed based on the coal feed rate.

[0073] In particular, the mapping relationship between coal feed rate and ideal scraper chain speed can be established through experimental calibration methods. Specifically, a coal flow simulation is conducted on the aforementioned standard test platform. Coal is controlled to enter the scraper conveyor at a set feed rate. The scraper chain speed is gradually increased while the feed rate is monitored in real time. During this process, the changes in the accumulation thickness of the coal seam at the scraper conveyor feed end are simultaneously monitored. When the coal seam accumulation thickness tends to be stable, that is, there is no obvious accumulation, the corresponding scraper chain speed is determined as the ideal chain speed value for that feed rate.

[0074] By repeating the above experimental process, multiple sets of paired data of different coal feed rates and corresponding ideal scraper chain speeds were obtained, and a mathematical mapping relationship between the two was constructed using a fitting algorithm.

[0075] b) If the migration direction deviation angle is greater than the allowable deviation threshold, the deviation angle between the migration direction deviation angle and the allowable deviation threshold is introduced as a compensation factor to correct the original mapping relationship between the coal feed speed and the ideal scraper chain speed to generate a new chain speed adjustment. At the same time, the piezoelectric ceramic actuator group embedded below the front end area of the scraper is activated for vibration excitation. During the execution of the above-mentioned adjustment and excitation operations, the coal particle migration status is continuously monitored. Once it is detected that the migration direction deviation angle meets the allowable deviation threshold requirement again, the original mapping relationship is called again according to the current coal feed speed to restore to the standard chain speed adjustment mode.

[0076] Applicable to the above operation description is that when the migration direction deviation angle is greater than the allowable deviation threshold, it indicates that the coal particle migration path has significantly deviated. The main reasons for this phenomenon may include: the scraper chain runs too fast, causing the coal particles to drift inertia during migration, thereby deviating from the expected trajectory; or due to insufficient excitation energy, poor coal flow fluidity and other factors, the coal particles do not respond sufficiently to the directional stress traveling wave.

[0077] To address the above problems, dynamic adjustment is performed by reducing the scraper chain speed. Its mechanism of action is reflected in two aspects: on the one hand, it can effectively reduce the inertia effect of coal particles during migration and reduce the probability of path drift; on the other hand, it prolongs the residence time of coal particles in the excitation area, so that they can more fully respond to the elastic traveling waves excited by the piezoelectric ceramic actuator, thereby enhancing the consistency and controllability of the migration direction, and improving the overall migration effect and control accuracy.

[0078] In the above, the deviation angle between the migration direction deviation angle and the allowable deviation threshold is introduced as a compensation factor to correct the mapping relationship between the original coal feed speed and the ideal scraper chain speed. The core principle is that the larger the migration direction deviation angle, the less sufficient the stimulated response of the coal flow or the more significant the inertial drift, and the higher the control intensity required to improve the migration effect.

[0079] Specifically, the corresponding scraper chain speed correction amount is calculated according to the deviation angle, and the correction amount is subtracted from the ideal scraper chain speed output by the original mapping relationship to obtain the corrected target chain speed value.

[0080] In particular, the calculation of the scraper chain speed correction amount based on the deviation angle can establish a quantitative functional relationship between the migration direction deviation angle and the scraper chain speed correction amount through a standard test platform.

[0081] Based on the above examples, the corrected target chain speed expression is: , where represents the ideal scraper chain speed obtained from the original mapping relationship, Indicates the deviation angle between the migration direction deviation angle and the allowable deviation threshold. Indicates the chain speed correction required for unit deviation angle.

[0082] Specifically, on a standardized experimental platform, coal is controlled to enter the scraper conveyor at a set feed speed, and the deviation angle between the actual migration direction of coal particles and the target direction is simultaneously collected.

[0083] On this basis, the scraper chain running speed is gradually adjusted, and the improvement effect of the migration path is observed. The corresponding migration direction deviation angle and the ideal chain speed correction value required to achieve path correction in each set of experiments are recorded, thereby constructing an experimental data set between the two.

[0084] By fitting the data set, the functional relationship between the migration direction deviation angle and the scraper chain speed correction was extracted.

[0085] Furthermore, while reducing the scraper chain speed, the piezoelectric ceramic actuator group embedded under the front end area of the scraper is activated for vibration excitation. Its purpose is to cope with the dynamic changes in coal flow caused by the reduction in chain speed. Specifically, when the scraper chain speed decreases, the amount of coal carried on the trough body per unit time increases relatively under the premise that the coal feed speed remains unchanged, resulting in a longer residence time of the front coal seam, an increase in the coal seam height, an increase in the local accumulation effect, and a risk of forming a new accumulation uplift area. In this case, by enhancing the local vibration energy, the friction and adhesion between the coal particles are destroyed, the fluidity of the coal flow is improved, and the accumulation and solidification of the front coal seam caused by the reduction in chain speed is prevented, which helps to inhibit the formation of new accumulation uplift areas.

[0086] The anti-rebound maintenance module starts micro-pulse vibration with a voltage step-down in the accumulation bulge area after the directional stress traveling wave action ends, and collects vibration data of the accumulation depression area in real time through a vibration sensor, and then dynamically adjusts the micro-pulse output state according to the vibration change.

[0087] It's important to understand that the aforementioned termination of the directional stress traveling wave refers to the completion of coal migration from the uplifted area to the depressed area, with the coal flow distribution approaching dynamic equilibrium. Specifically, the migration status can be determined by real-time monitoring of changes in coal flow density in the uplifted area during the migration process. When the coal flow density in this area drops to between the preset upper and lower density limits, it indicates that the coal in that area has essentially completed its outward migration, effectively decongesting the original uplifted area. At this point, the directional stress traveling wave excitation can be determined to have concluded.

[0088] The above scheme can be optionally implemented to start the micro-pulse vibration with voltage step reduction after the directional stress traveling wave action ends as follows: for the piezoelectric ceramic actuator group corresponding to the stacking ridge area, the excitation voltage is gradually reduced according to the preset attenuation step and time interval to form multiple voltage steps. Each voltage step lasts for a set period of time and then enters the next lower voltage level until the excitation voltage drops to zero.

[0089] The above-mentioned attenuation step refers to the amplitude of each voltage drop, which is usually set to a certain proportion of the initial excitation voltage, such as 20%. The time interval refers to the time delay between adjacent voltage steps, which is generally set according to the vibration response time of the coal particles. In particular, this time interval is initially set and will be adjusted later based on the vibration data of the accumulation depression area.

[0090] The small-amplitude, gradually weakening vibration energy generated by the above operation can effectively suppress the rebound behavior of coal particles.

[0091] The above scheme can be further optionally implemented to collect vibration data of the accumulation depression area in real time through a vibration sensor. Please refer to the following implementation: during the continuous excitation period of each voltage step, the vibration data of the coal particles are collected according to the set time resolution through a vibration sensor arranged below the accumulation depression area, where the coal particle vibration data can be vibration acceleration, reflecting the impact and friction between the coal particles and the trough surface or other particles. A higher acceleration value usually indicates a stronger collision or friction force, indicating that there is a large kinetic energy exchange inside the coal flow.

[0092] In the above scheme, further optional implementation is made, see Figure 3As shown, the micro-pulse output state is dynamically adjusted according to the vibration change as follows: the coal particle vibration data collected at the current moment is compared with the previous moment. If the coal particle vibration at the current moment is higher than that at the previous moment, the relative position of the current moment in the current voltage step excitation cycle is identified. If it is at the end of the current voltage step excitation period, the excitation duration of the current voltage step is extended until the coal particle vibration attenuates. If it is before the end of the current voltage step excitation period, the original voltage excitation is maintained.

[0093] It should be understood that in the process of implementing voltage step micro-pulse excitation on the accumulation uplift area, when the voltage step starts to take effect within the excitation cycle of each voltage step, the accumulation depression area will be affected, which will cause a vibration response of the trough body and the coal particles on it, thereby causing the coal particles to break away from the static state due to disturbance, the friction between the particles is overcome, the vibration acceleration rises rapidly, and reaches a peak value in a short time; then, as the coal flow gradually migrates to the depression area and tends to be evenly distributed, the local accumulation energy is released, and the vibration acceleration shows a trend of slow decay.

[0094] This vibration response characteristic indicates that the effective excitation process of each voltage step should be marked by the transition of vibration acceleration from high to low. Therefore, when implementing a dynamic control strategy based on vibration data, it is only necessary to pay attention to the situation where the vibration acceleration increases - this usually means that the current excitation has not yet completed the expected migration task, or there is a risk of local disturbance.

[0095] Specifically: During each voltage step excitation, the system continuously collects the coal particle vibration acceleration signal and compares it with the previous moment.

[0096] If it is detected that the vibration acceleration at the current moment is higher than that at the previous moment, it indicates that the coal flow is still in an active migration state or the local disturbance is intensified. At this time, the relative position of the current time point in the current voltage step excitation cycle is further identified. If the current time point is at the end of the excitation cycle, but the vibration acceleration still does not show an obvious attenuation trend, it means that the excitation effect of the current voltage step has not met expectations. Terminating the excitation as originally planned may cause coal particles to rebound or re-accumulate. At this time, the excitation duration of the current voltage step should be extended until the vibration signal shows obvious attenuation to ensure that the coal flow has enough time to complete the structural adjustment on the migration path. If the current time point is still before the end of the excitation cycle, the original voltage excitation is maintained unchanged and the established incentive plan is continued.

[0097] In particular, in order to accurately identify the position of the end point in each voltage step excitation cycle, the following calibration process can be carried out on the standardized experimental platform: during the action of each voltage step, the curve of the change of coal particle vibration acceleration over time is recorded, and the time point when the vibration acceleration starts to drop from a high value and enters attenuation is identified from the change curve, and the end point position in the average sense is extracted by statistically analyzing multiple groups of experimental results.

[0098] The above embodiments may be implemented in whole or in part through software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments may be implemented in whole or in part in the form of a computer program product.

[0099] Those skilled in the art will appreciate that the modules and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0100] In addition, each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0101] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0102] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A coal transportation equipment control system for a top coal working face, characterized in that: include: Coal flow distribution scanning module: This module uses an infrared laser grid scanner to capture the three-dimensional point cloud data of the coal flow cross section on the scraper conveyor in real time. Based on the spatial density distribution of the point cloud, it identifies the coordinates of the accumulation depression and uplift areas, and generates a vector map of the uneven area with spatial coordinates. Directional migration control module: Piezoelectric ceramic array actuators are arranged in zones at the bottom of the scraper trough. The actuator groups in the stacking ridge area and the adjacent transition area are activated according to the vector map coordinates. Through phase difference control, a directional stress traveling wave is formed on the trough surface from the ridge area to the depression area. Collaborative control module: A high-speed camera is used to capture the coal particle migration direction in real time, while a laser rangefinder is used to monitor the coal feed speed at the front end of the scraper. Based on the coal particle migration direction and the coal feed speed at the front end of the scraper, the module collaboratively outputs scraper chain speed adjustment instructions. Anti-rebound maintenance module: After the directional stress traveling wave action ends, micro-pulse vibration with decreasing voltage steps is started in the accumulation uplift area, and the vibration data of coal particles in the accumulation depression area is collected in real time through the vibration sensor, and the micro-pulse output state is dynamically adjusted according to the vibration changes.

2. A top coal working face coal transportation equipment control system according to claim 1, characterized in that: The coal flow distribution scanning module is implemented as follows: An infrared laser emitter array is evenly arranged at set intervals on the longitudinal axis of the scraper conveyor, and an optical imaging device is configured on the opposite side of the scraper conveyor; An infrared laser emitter array is used to emit parallel laser beams to penetrate the coal flow layer. An optical imaging device is used to capture the scattered light spot image produced by the laser beam on the surface of the coal particles, thereby constructing the three-dimensional spatial point cloud data of the coal flow cross section. The obtained three-dimensional spatial coordinate point cloud data is statistically analyzed using a sliding window to calculate the distribution density of the point cloud data within a unit area to construct a spatial density distribution map of the coal flow section. According to the preset density upper threshold and density lower threshold, the bulge area where the coal flow distribution density is higher than the density upper threshold and the depression area where the density is lower than the density lower threshold are identified respectively, and their corresponding spatial coordinate ranges are marked; The coordinate information of the accumulation uplift area and the accumulation depression area is converted into a vector map of the uneven area with spatial coordinates, and is refreshed and updated at a preset time period.

3. The coal transportation equipment control system for a top coal working face according to claim 1, characterized in that: The process of arranging the piezoelectric ceramic array actuators in the bottom of the scraper groove in different zones is as follows: Obtain the geometric dimensions of the scraper conveyor trough and divide the scraper trough bottom surface into zones based on the effective action area of a single piezoelectric ceramic actuator; A piezoelectric ceramic actuator is embedded in the bottom surface of the groove corresponding to each partition, and each actuator is independently connected to a driving circuit.

4. A coal transportation equipment control system for a top coal working face according to claim 1, characterized in that: The specific contents of activating the actuator groups in the stacking uplift area and the adjacent transition area according to the vector map coordinates and forming a directional stress traveling wave from the uplift area to the depression area on the surface of the tank body through phase difference control are as follows: According to the accumulation uplift area and depression area marked in the uneven area vector map, the two are paired based on the principle of spatial proximity to determine the accumulation depression area paired with each accumulation uplift area; The path direction between the raised and recessed areas is extracted based on their spatial relationship, and the area from the stacked raised area to the recessed area is defined as the adjacent transition zone. This activates the piezoelectric ceramic actuator group embedded below the stacked raised area and the adjacent transition zone. A sinusoidal excitation voltage signal with the same frequency and adjustable amplitude is applied to the actuator group corresponding to the ridge area, while a cosine excitation voltage signal with the same frequency but a phase lag of π / 2 is applied to the actuator group corresponding to the adjacent transition area. The phase difference between the sine wave and the cosine wave is superimposed to generate a surface wave that propagates in one direction from the raised area to the depressed area. The distance between the stacking ridge and depression areas is obtained based on their locations, and the excitation voltage amplitude of the stacking ridge area is determined in combination with the preset unit distance excitation voltage amplitude. At the same time, an excitation voltage is configured for the actuator in the adjacent transition area, and its value is set to be attenuated relative to the excitation voltage of the ridge area according to a preset ratio.

5. The coal transportation equipment control system for a top coal working face according to claim 1, characterized in that: The operation of capturing the coal particle migration direction in real time by a high-speed camera is as follows: A high-speed camera installed above the scraper trough continuously captures images of the accumulation ridge area to obtain a sequence of coal flow images under the excitation of the piezoelectric ceramic actuator. The spatial position information of coal particles in each frame of the collected continuous frame images is identified in turn, and the motion vector of the coal particles is obtained based on the displacement relationship between adjacent frames. Therefore, the coal particle migration path in the accumulation uplift area is established by temporal analysis of the coal particle position changes in multiple frame images, and then the coal particle migration direction is extracted.

6. A top coal working face coal transportation equipment control system according to claim 1, characterized in that: The implementation of using a laser rangefinder to monitor the coal feeding speed at the front end of the scraper is as follows: During the operation of the scraper conveyor, a laser rangefinder is deployed above the scraper trough so that its beam vertically covers the coal flow accumulation area at the feed end of the scraper conveyor; The laser rangefinder continuously emits laser pulses at a set frequency and receives the echo signal reflected by the coal surface at the feed end. The distance between the top of the coal seam at the feed end of the scraper conveyor and the sensor installation reference surface is calculated based on the flight time. The actual coal accumulation height is calculated based on the calculated distance value and the scraper trough height; The coal feeding rate is obtained by calculating the change in coal pile height at adjacent monitoring moments.

7. A control system for coal transportation equipment at a top coal working face according to claim 4, characterized in that: The coordinated output scraper chain speed adjustment instruction is implemented as follows: The path direction extracted based on the spatial position relationship between the uplift area and the depression area is used as the demand migration direction; The coal particle migration direction is compared with the required migration direction to obtain the migration direction deviation angle, and compared with the set allowable deviation threshold; a) If the deviation angle of the migration direction meets the allowable deviation threshold, the pre-established mapping relationship between the coal feed speed and the ideal scraper chain speed is called, and the real-time monitored coal feed speed is substituted into the mapping relationship as an input parameter to calculate the corresponding scraper chain speed target value, and then the scraper chain operating speed is adjusted accordingly; b) If the migration direction deviation angle is greater than the allowable deviation threshold, the deviation angle between the migration direction deviation angle and the allowable deviation threshold is introduced as a compensation factor to correct the original mapping relationship between the coal feed speed and the ideal scraper chain speed to generate a new chain speed adjustment. At the same time, the piezoelectric ceramic actuator group embedded below the front end area of the scraper is activated for vibration excitation. During the execution of the above-mentioned adjustment and excitation operations, the coal particle migration status is continuously monitored. Once it is detected that the migration direction deviation angle meets the allowable deviation threshold requirement again, the original mapping relationship is called again according to the current coal feed speed to restore to the standard chain speed adjustment mode.

8. A top coal working face coal transportation equipment control system according to claim 4, characterized in that: The micro-pulse vibration with step-by-step voltage reduction is implemented as follows: After the directional stress traveling wave action ends, the excitation voltage of the piezoelectric ceramic actuator group corresponding to the accumulation uplift area will be gradually reduced according to the preset attenuation step and time interval to form multiple voltage steps. Each voltage step will enter the next lower voltage level after the set length of time until the excitation voltage drops to zero.

9. A control system for coal transportation equipment at a top coal working face according to claim 8, characterized in that: The real-time collection of coal particle vibration data in the accumulation depression area by the vibration sensor is described in the following implementation: During the continuous excitation period of each voltage step, the vibration data of the coal particles are collected according to the set time resolution through the vibration sensor arranged below the accumulation depression area.

10. A control system for coal transportation equipment at a top coal working face according to claim 8, characterized in that: The dynamic adjustment of the micro-pulse output state according to the vibration change is as follows: Compare the coal particle vibration data collected at the current moment with that at the previous moment. If the coal particle vibration at the current moment is higher than that at the previous moment, identify the relative position of the current moment in the current voltage step excitation cycle. If it is at the end of the current voltage step excitation period, extend the excitation duration of the current voltage step until the coal particle vibration attenuates. If it is before the end of the current voltage step excitation period, maintain the original voltage excitation.

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