An intelligent control method for goaf air leakage under the interference of multiple fans' joint operation

Abstract

The present invention discloses an intelligent control method for goaf air leakage under the interference of the joint operation of multiple fans. The method is based on the control box receiving the air volume and gas concentration data monitored in real time by the sensor and feeding it back to the host computer. The host computer calculates the actual air leakage of the working surface facing the goaf in real time, and the PLC with a variable domain fuzzy PID system in the control box makes a corresponding servo motor signal. The servo motor controls the wind window area to adjust the air volume, and the host computer makes further instructions based on the regulated air leakage until the set air leakage requirement is reached. This method can intelligently control the air leakage of the working surface facing the goaf according to demand, and ultimately effectively treat the air leakage problem in the goaf caused by the interference of the joint operation of multiple fans, eliminate the hidden dangers caused by air leakage, and ensure safe production in the mine.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining, and in particular to an intelligent control method for air leakage in a goaf under interference from the combined operation of multiple fans. Background Art

[0002] Due to illegal and irregular mining practices during the original mining process, the goafs of the mines after resource integration became interconnected. When adjacent working faces of adjacent mines were mining the same coal seam, a large goaf had already formed due to the mining of the nearby overlying coal seam. As the working faces of this layer mined and the roof collapsed behind them, the existing goaf became connected to the goaf of the overlying coal seam. Simultaneously, the combined negative pressure of multiple fans caused a pressure difference between the goafs of adjacent mines. This pressure difference easily caused airflow from the working face to flow into the goaf, resulting in air leakage in the goaf. This led to unstable ventilation systems, insufficient airflow from the working face, spontaneous combustion of coal in the goaf, and the accumulation of gas in return air corners, posing a threat to mine safety.

[0003] At present, the commonly used methods for controlling air leakage in goafs are as follows: ① Grouting: Slurry is injected or directly sprayed into the goaf. The slurry can penetrate into the gaps between coal and gangue, reducing the reaction surface between coal and oxygen, reducing the porosity in the goaf, enhancing the cementation of crushed coal and gangue, and providing airtightness in the area, thereby reducing air leakage in the goaf. ② Polymer material filling: Polymer material is injected into the goaf leakage channel in the return air corner or the newly formed goaf leakage channel behind the hydraulic support of the working face, so that it is tightly combined with the coal rock mass with cracks, thereby achieving the effect of reducing air leakage. ③ Windbreak wall technology: Walls are built at the corners of the inlet and return air, and sand is filled in the middle. Some use non-combustible materials such as river sand and loess to be filled into woven bags to build a windbreak wall. Try to seal the two corners tightly to reduce air leakage into the goaf.

[0004] The above methods have some effect on reducing air leakage from the working face into the goaf, but they require timely construction as the working face advances, consume a lot of manpower and material resources, have a low level of intelligence, and are not effective in controlling air leakage in large goafs. In addition, the negative pressure in the mine is greatly affected by changes in climatic conditions, which can cause different amounts of air leakage in the goaf at different time periods. The goaf leakage situation is further complicated by the interference of multiple fans operating in combination, increasing the difficulty of goaf leakage control. Therefore, it is necessary to provide an intelligent control method for goaf leakage under the interference of multiple fans operating in combination. Summary of the Invention

[0005] When adjacent working faces of the same coal seam are mined in adjacent mines, a large area of ​​goaf has been formed due to the mining of the overlying nearby coal seam. With the mining of the working face of this layer and the collapse of the rear roof, the existing goaf is connected with the goaf of the overlying coal seam. At the same time, due to the combined interference of the negative pressure of multiple fans, air leakage occurs between the goafs of adjacent mines. To solve this problem, the present invention proposes an intelligent control method for goaf leakage under the interference of the combined operation of multiple fans, and a method for reducing air leakage in the goaf.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] An intelligent control method for goaf air leakage under the interference of multiple fans operating in conjunction uses sensors to monitor air volume and gas concentration in real time. A control box receives the monitoring data from the sensors and feeds it back to a host computer. The host computer calculates the actual air leakage from the working surface to the goaf in real time. The servo motor in the control box controls the air window area to adjust the air volume. The host computer issues further instructions based on the adjusted air leakage until the set air leakage requirement is achieved. The specific steps are as follows:

[0008] Step 1. Install ultrasonic wind speed sensors in the air intake and return air lanes on both sides of the working face in the goaf's air leakage area, install smart dampers and windows in the air intake lanes, and install supporting control boxes near the smart dampers and windows;

[0009] Step 2. The host computer calculates the actual air leakage Q in real time based on the air volume of the air inlet and return air channels on both sides of the working face 实 , set the working surface air leakage Q in the host computer according to the working conditions 设 , the host computer calculates the actual air leakage Q in real time 实 and the set working surface air leakage Q 设 The difference e, and the rate of change of the difference e c , and the difference e and the rate of change of the difference e c Transmit to the control box;

[0010] Step 3. The actual air leakage Q calculated by the host computer 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c As input variables, it is transmitted to the variable universe fuzzy PID control system in the control box; the expansion factor is obtained through the variable universe module, and the expansion factor regulates the initial proportional factor and the initial quantization factor; the three parameters K of PID are obtained through the fuzzy adjustment module I , K P , K D ; The air leakage difference e and the difference change rate e c , K I , K P , K DAs the input variable of the PID controller module, the PID controller module outputs the control signal of the servo motor;

[0011] Step 4. The servo motor adjusts the air door-window wind area according to the received control signal, changes the air intake, and balances the pressure difference between the monitored goaf and the surrounding goaf until the actual air leakage volume Q 实 Lower than or equal to the set air leakage Q 设 If the upper computer calculates that the air leakage volume does not reach the set value, it will re-enter step 3 and start the calculation until the actual air leakage volume is lower than or equal to the set air leakage volume.

[0012] Furthermore, the control box is a KXJ127 mining explosion-proof and intrinsically safe PLC control box. A variable domain fuzzy PID control system is set in the PLC control box. The signal receiving end of the control box is connected to the ultrasonic wind speed sensor for detecting the air volume, the methane sensor T0 at the return air corner of the coal mining working face, and the methane sensors in the return air lanes of the two coal mining working faces; the signal output end of the control box is connected to the control end of the servo motor; the control box and the host computer and the servo motor signals are transmitted bidirectionally.

[0013] Furthermore, the variable universe fuzzy PID control system of the control box includes a variable universe module, a fuzzy adjustment module and a PID controller module.

[0014] Furthermore, ultrasonic wind speed sensors are set in the air inlet and return air lanes of the leaking working face in the goaf. Starting from 60m away from the working face cut, a group of ultrasonic wind speed sensors for monitoring the air volume in the air inlet and return air lanes of the leaking working face are installed at equal intervals in the direction of the goaf, and the number of ultrasonic wind speed sensors on both sides of the air inlet and return air lanes is no less than 3 groups.

[0015] Furthermore, in step 2, the host computer calculates the actual air leakage Q in real time 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c , the calculation method is as follows:

[0016] Step 2.1 Assume that the air volume monitored by the ultrasonic wind speed sensor in the air inlet channel is Q 进i , represents the air volume monitored by the i-th sensor. Similarly, the air volume monitored by the ultrasonic sensor in the return air channel is Q 回i , the air volume of the air inlet channel is Where n represents the number of sensors, and the calculation is similar. Actual air leakage of working surface Q 实 =Q 进 -Q 回 ;

[0017] Step 2.2 The difference between the actual air leakage and the set air leakage is e=Q 实 -Q设 , the rate of change of difference

[0018] Furthermore, the upper computer sets the minimum required air volume of the working surface, and the return air volume is regarded as the working surface air volume. If the working surface air volume is lower than the minimum required air volume of the working surface, the air leakage volume Q needs to be reset. 设 .

[0019] Furthermore, the variable universe fuzzy PID control system specifically includes the following contents:

[0020] S1, let the input variable difference e and the difference change rate e c The initial domains are [-e0, e0], [-e c0 , e c0 ], output variable ΔK P , ΔK I , ΔK D The initial domains are [-K p0 , K p0 ]、[-K i0 , K i0 ]、[-K d0 , K d0 ], and set the input variable difference e and the difference change rate e c And the output variable ΔK P , ΔK I , ΔK D The fuzzy domain of is [-M, M];

[0021] S2, the actual air leakage Q 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c As the input variable of the variable universe module, the scaling factor α of the input variable difference e is obtained using the scaling factor function model e , difference change rate e c The expansion factor α ec and three output variables ΔK P , ΔK I , ΔK D The expansion factor β P , β I , β D ; The scaling factor function model is as follows:

[0022] Enter the scaling factor:

[0023] Output scaling factor:

[0024]

[0025] Where λ∈(0,1), k>0; KI is the proportional factor; P i is the input weight coefficient; e i (τ) is the input variable error; β(0) is the initial value of the output universe scaling factor;

[0026] S3, according to the initial domain and fuzzy domain set in S1, the initial quantization factor K is obtained e0 , K ec0 and the initial scale factor L P0 、L I0 、L D0 ,Right now The scaling factor α obtained in S2 e , α ec For the initial quantization factor K e0 , K ec0 Adjust to get the quantization factor K e With K ec , that is, K e =α e ·K e0 , K ec =α ec ·K ec0 ; Difference e and rate of change of difference e c As the input variable of the fuzzy adjustment module, the fuzzy quantity e is obtained by fuzzification processing through the action of quantization factors. * With e c * , that is, e * =K e ·e, e c * =K ec ·e c ; Set fuzzy sets and fuzzy rules with reference to expert domain knowledge and use the center of gravity method to calculate the fuzzy quantity e * With e c * Perform fuzzy processing to obtain the output value ΔK P * , ΔK I * , ΔK D * ; Using the scaling factor β of the output variable P , β I , β D Adjust the initial scale factor to obtain the scale factor L P 、L I 、L D , that is, L P =β P ·L P0 、L I =β I·L I0 , L D =β D ·L D0 ; Output value ΔK P * , ΔK I *, ΔK D * Proportional adjustment is performed on the three proportional factors to obtain the parameter adjustment value ΔK P , ΔK I , ΔK D , that is, ΔK P =ΔK P * ·L P , ΔK I =ΔK I * ·L I , ΔK D =ΔK D * ·L D ;

[0027] S4, the initial value K is obtained by the PID controller parameter tuning method P0 , K I0 , K D0 , according to the adjustment amount ΔK obtained above P , ΔK I , ΔK D Adjust the initial value to obtain the three parameters K of PID control P =K P0 +ΔK P , K I =K I0 +ΔK I , K D =K D0 +ΔK D ; The difference e and the rate of change of the difference e c And 3 parameters K P , K I , K D As the input variable of the PID controller module, the PID controller module outputs a control signal that is transmitted to the servo motor; the discretization formula of the PID control algorithm is:

[0028]

[0029] Where u n is the output result after adjusting n times, e n The actual air leakage volume Q for the nth time 实 and set air leakage Q 设 Difference, T s To control the time, KP is the proportional constant, T I Integration time constant, T D Differentiation time constant.

[0030] Furthermore, the upper computer sets the minimum required air volume for the working surface. If the air volume on the working surface after adjustment is lower than the minimum required air volume, the air leakage volume Q is reset. 设 The host computer simultaneously monitors the gas concentration data of the return air corner T0 and the return air channel in real time. When the gas concentration data exceeds the limit, the host computer turns on the gas concentration warning, sends a warning instruction to the control box for voice warning, and the control box outputs a control signal to the servo motor to control the intelligent damper-window opening to return to the maximum state. After the gas concentration returns to normal, the leakage volume Q is reset according to the real-time monitored air volume. 设 And ensure that the gas concentration no longer exceeds the limit and continue to adjust.

[0031] In summary, the invention has the following beneficial effects:

[0032] The present invention can mainly effectively balance the pressure-energy difference between the goaf of the working face and the goaf of the surrounding working faces, reduce the impact of air leakage in the goaf on the ventilation system, and at the same time monitor the air volume conditions of the air intake and return air channels on both sides of the working face and the air leakage conditions in the goaf at any time, and can automatically adjust the air volume of the air intake channel, effectively control the air leakage of the working face, and use the variable domain fuzzy PID control method to realize the optimal control of the wind window, realizing the advantages of short adjustment time, high steady-state accuracy, small steady-state error, small overshoot, etc., and realizing real-time intelligent regulation of air leakage in the goaf. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is an example diagram illustrating this method

[0034] Figure 2 Schematic diagram of the structure of this method

[0035] Figure 3 Variable universe fuzzy PID relationship diagram

[0036] In the figure: 1-intelligent damper-window; 2-control box; 3-ultrasonic wind speed sensor; 4-A coal industry air intake lane; 5-A coal industry return air lane; 6-A coal industry goaf; 7-overlying goaf; 8-B coal industry goaf; 9-servo motor.

[0037] Specific implementation cases

[0038] The present invention is described clearly and completely below with reference to the accompanying drawings and embodiments. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0039] like Figures 1 to 3 As shown, the present invention discloses an intelligent control method for goaf air leakage under the interference of multiple fans in joint operation, which is characterized by using sensors to monitor air volume and gas concentration in real time, a control box receiving the monitoring data of the sensors and feeding it back to a host computer, the host computer calculating the actual air leakage of the working surface toward the goaf in real time, a servo motor in the control box controlling the wind window area to control the air volume, and the host computer issuing further instructions based on the regulated air leakage until the set air leakage requirement is reached. The specific steps are as follows:

[0040] Step 1: Install ultrasonic wind speed sensors in the intake and return airways on both sides of the working face in the area of ​​goaf leakage. Install intelligent dampers and windows in the intake airways, and install a matching control box near the intelligent dampers and windows. These sensors monitor the air volume in the intake and return airways on both sides of the working face in real time. The control box is connected to the host computer and the ultrasonic wind speed sensors, respectively. The return air corner methane sensor T0 and the return airway methane sensors T1 and T2 are also connected to the control box.

[0041] Step 2: The host computer calculates the actual air leakage Q in real time based on the air volume of the air inlet and return air channels on both sides of the working face. 实 , set the working surface air leakage Q in the host computer according to the working conditions 设 , the host computer calculates the actual air leakage Q in real time 实 and the set working surface air leakage Q 设 The difference e, and the rate of change of the difference e c and transmit the data to the control box.

[0042] Step 3: The actual air leakage Q calculated by the host computer 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c As input variables, it is transmitted to the variable universe fuzzy PID control system in the control box; the expansion factor is obtained through the variable universe module, and the expansion factor regulates the initial proportional factor and the initial quantization factor; the three parameters K of PID are obtained through the fuzzy adjustment module I , K P , K D ; The air leakage difference e and the difference change rate e c , K I , K P , K D As the input variable of the PID controller module, the PID controller module outputs the control signal of the servo motor.

[0043] Step 4: The servo motor intelligently adjusts the air door and window area according to the signal, changes the air intake, and balances the pressure difference between the goaf and the surrounding goaf until the actual air leakage volume Q 实 Lower than or equal to the set air leakage Q 设 The upper computer sets the minimum required air volume for the working surface, and the return air volume is regarded as the working surface air volume. If the working surface air volume is lower than the minimum required air volume, the air leakage volume Q needs to be reset. 设 .

[0044] In step 1, the intelligent air door-window is installed in the air inlet tunnel, and the prerequisite is that the goaf of this working face leaks air to the surrounding goafs.

[0045] In step 1, the intelligent damper-window is equipped with a servo motor to control the size of the window opening, wherein the servo motor is connected to the control box and receives the adjustment signal from the control box; the control box and the host computer and the servo motor can transmit signals in both directions. The control box receives the data monitored by the sensor and feeds it back to the host computer, and receives instructions and data transmitted by the host computer. The ultrasonic wind speed sensor is arranged in the air intake and return air lanes of the air leakage working face in the goaf. A group of ultrasonic sensors is installed at equal intervals starting from 60m from the working face cut toward the goaf, and the number of ultrasonic wind speed sensors on both sides is not less than 3 groups. In this embodiment, the number of sensors is 3 groups, which are used to monitor the air volume in the air intake and return air lanes of the air leakage working face.

[0046] In step 2, the host computer monitors the data of the ultrasonic wind speed sensors of the air inlet and return air channels in real time and calculates the air volume of the air inlet and return air channels in real time, taking the average value as the actual air volume Q 实 , calculate the actual air leakage Q based on the air volume of the air inlet and return air channels 实 , the calculation method is as follows:

[0047] Step 2.1 Assume that the air volume monitored by the three ultrasonic wind speed sensors in the air inlet tunnel is Q 进i , represents the air volume monitored by the i-th sensor. Similarly, the air volume monitored by the ultrasonic sensor in the return air channel is Q 回i , in this embodiment, they are Q 进1 , Q 进2 , Q 进3 Similarly, the air volume monitored by the three groups of ultrasonic sensors in the return air channel is Q 回1 , Q 回2 , Q 回3 ,Right now:

[0048] The air volume of the air inlet channel is The same calculation Actual air leakage of working surface Q 实 =Q 进 -Q 回 .

[0049] Step 2.2 The difference between the actual air leakage and the set air leakage is e=Q 实 -Q 设 , the rate of change of difference

[0050] The control box is a KXJ127 explosion-proof and intrinsically safe PLC control box for mining. The PLC is equipped with a variable universe fuzzy PID control system. The variable universe fuzzy PID control system includes a variable universe module, a fuzzy adjustment module, and a PID controller module. The variable universe fuzzy PID control system specifically includes the following:

[0051] S1, let the input variable difference e and the difference change rate e c The initial domains are [-e0, e0], [-e c0 , e c0 ], output variable ΔK P , ΔK I , ΔK D The initial domains are [-K p0 , K p0 ]、[-K i0 , K i0 ]、[-K d0 , K d0 ], and set the input variable difference e and the difference change rate e c And the output variable ΔK P , ΔK I , ΔK D The fuzzy domain of is [-M, M].

[0052] S2, the actual air leakage Q 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c As the input variable of the variable domain module, the input variable difference e and the difference change rate e are obtained through adjustment of the scaling factor function model in the variable domain module. c The expansion factor α e , α ec and output variable ΔK P , ΔK I , ΔK D The expansion factor β P , β I , β D The scaling factor function model is as follows:

[0053] Input scaling factor: α(x) = 1-λe -kx2

[0054] Output scaling factor:

[0055]

[0056] Where λ∈(0,1), k>0; K I is the proportional factor; P i is the input weight coefficient; e i (τ) is the input variable error; β(0) is the initial value of the output universe scaling factor.

[0057] S3, according to the initial domain and fuzzy domain set in S1, the initial quantization factor K is obtained e0 , K ec0 and the initial scale factor L P0 , L I0 , L D0 ,Right now The obtained input variable difference e and the difference change rate e c The expansion factor α e , α ec For the initial quantization factor K e0 , K ec0 Adjust to get the quantization factor K e With K ec , that is, K e =α e ·K e0 , K ec =α ec ·K ec0 ; Difference e and rate of change of difference e c As the input variable of the fuzzy adjustment module, the fuzzy quantity e is obtained by fuzzification processing through the action of quantization factors. * With e c * , that is, e * =K e ·e, e c * =K ec ·e c ; Set fuzzy sets and fuzzy rules with reference to expert domain knowledge and use the center of gravity method to calculate the fuzzy quantity e * With e c * Perform fuzzy processing to obtain the output value ΔK P * , ΔK I * , ΔK D * ; Using the scaling factor β of the output variable P , β I , β D Adjust the initial scale factor to obtain the scale factor L P , L I , L D , that is, LP =β P ·L P0 、L I =β I ·L I0 、L D =β D ·L D0 ; Output value ΔK P * , ΔK I *, ΔK D * Proportional adjustment is performed to obtain the parameter adjustment value ΔK P , ΔK I , ΔK D , that is, ΔK P =ΔK P * ·L P , ΔK I =ΔK I * ·L I , ΔK D =ΔK D * ·L D .

[0058] S4, the initial value K is obtained by the PID controller parameter tuning method P0 , K I0 , K D0 , according to the adjustment amount ΔK obtained above P , ΔK I , ΔK D Adjust the initial value to obtain the three parameters K of PID P =K P0 +ΔK P , K I =K I0 +ΔK I , K D =K D0 +ΔK D The difference e and the rate of change of the difference e c And 3 parameters K P , K I , K D As the input variable of the PID controller module, the PID controller module outputs the control signal. The discretization formula of the PID control algorithm is:

[0059]

[0060] Where u n is the output result after adjusting n times, e n The actual air leakage volume Q for the nth time 实and set air leakage Q 设 Difference, T s To control the time, K P is the proportional constant, T I Integration time constant, T D Differentiation time constant.

[0061] In step 4, the servo motor receives the adjustment signal from the control box to adjust the opening of the intelligent damper-window to balance the pressure difference between the current goaf and the surrounding goaf, so as to achieve the purpose of controlling the air leakage. If the upper computer calculates that the air leakage does not reach the set value, it will re-enter step 2 to start the calculation until the actual air leakage is lower than or equal to the set air leakage. The upper computer sets the minimum required air volume of the working face. If the air volume of the working face after adjustment is lower than the minimum required air volume, the air leakage volume Q will need to be reset. 设 In this embodiment, taking the detection of methane concentration as an example, the host computer simultaneously monitors the methane concentration data of the return air corner T0 and the return air channels T1 and T2 in real time. When the uploaded methane concentration data exceeds the limit, the host computer will automatically warn and send a command to the control box to restore the opening of the intelligent damper-window to its original state. After the gas concentration returns to normal, the leakage volume Q is reset. 设 , continue to adjust.

[0062] Example 1: Arrangement of related devices

[0063] Ultrasonic wind speed sensors are arranged in the air intake and return air lanes on both sides of the working face in the area where the goaf is leaking. In this embodiment, a group of ultrasonic sensors is arranged every 10 meters from the working face cut hole 60 meters away from the goaf, and 3 groups are arranged on each side to monitor the air volume in the air intake and return air lanes of the leaking working face. Intelligent air doors and windows are installed in the air intake lanes. The intelligent air doors and windows are equipped with servo motors to control the opening size of the windows. A matching control box is installed near the intelligent air doors and windows, in which the servo motor is connected to the control box and receives the adjustment signal from the control box. The control box is connected to the host computer and the ultrasonic wind speed sensor respectively, and the methane sensor T0 at the return air corner of the coal mining working face and the methane sensors T1 and T2 in the return air lane of the coal mining working face are connected to the control box. The control box receives the data monitored by the sensors and feeds it back to the host computer, and receives instructions and data transmitted by the host computer.

[0064] Step 2: Set the air leakage rate Q of the working surface 设 , calculate the input variables of the variable universe fuzzy PID control system

[0065] The host computer monitors the data of ultrasonic wind speed sensors in the air intake and return air lanes in real time and calculates the air volume of the air intake and return air lanes in real time, taking the average value as the actual air volume, and infers the actual air leakage volume Q based on the air volume of the air intake and return air lanes. 实 ; Set the working surface air leakage Q in the host computer according to requirements设 , the host computer calculates the actual air leakage Q in real time 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c , and transmit the data to the control box. The calculation method is as follows:

[0066] ① The air volume monitored by ultrasonic wind speed sensors in the air inlet tunnel is Q 进1 , Q 进2 , Q 进3 Similarly, the air volume monitored by the ultrasonic sensor in the return air channel is Q 回1 , Q 回2 , Q 回3 .

[0067] ②The air volume of the air inlet tunnel is The same calculation Actual air leakage of working surface Q 实 =Q 进 -Q 回 .

[0068] ③The difference between the actual air leakage and the set air leakage is e=Q 实 -Q 设 , the rate of change of difference

[0069] Step 3: Output control signal of variable universe fuzzy PID system

[0070] The actual air leakage Q 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c As input variables, it is transmitted to the variable universe fuzzy PID control system in the control box. The expansion factor is obtained through the variable universe module, and the expansion factor regulates the initial proportional factor and the initial quantization factor; the three parameters K of PID are obtained through the fuzzy adjustment module. I , K P , K D The air leakage difference e and the difference change rate e c , K I , K P , K D As the input variable of the PID controller module, the PID controller module outputs the control signal of the servo motor.

[0071] Step 4: Adjust the window area to make the actual air leakage Q 实 Reach the set air leakage Q 设

[0072] The control box receives the control signal and transmits it to the servo motor. The servo motor adjusts the size of the intelligent damper-window opening according to the signal. By adjusting the size of the window area, the air intake volume is changed to a certain extent to balance the pressure difference between the goaf and the surrounding goaf. The upper computer monitors the actual air leakage volume Q in real time. 实 , if the host computer obtains the actual air leakage Q 实 The set air leakage volume Q is not reached 设 , will re-enter step 2 and start calculation until the actual air leakage reaches the set air leakage. The upper computer sets the minimum required air volume of the working surface. If the air volume of the working surface after adjustment is lower than the minimum required air volume, the air leakage volume Q will need to be reset. 设 The host computer monitors the methane concentration data of the return air corner T0 and the return air lanes T1 and T2 in real time. When the uploaded methane concentration data exceeds the limit, the host computer will automatically warn and send a command to the control box to restore the opening of the intelligent damper-window to its original state. When the gas concentration returns to normal, the leakage volume Q will be reset. 设 , continue to adjust.

[0073] Example 2: A and B Coal Mining are both adjacent mines integrating resources. The No. 2 coal seam in the area where A and B Coal Mining are located has been mined and a large area of ​​connected goaf has been formed. The No. 3 coal seam is now being mined, and the average distance between the No. 2 coal seam and the No. 3 coal seam is 7m. Among them, the 3304 working face of A Coal Mining and the 30303 working face of B Coal Mining were affected by the collapse of the roof when mining the No. 3 coal seam at the same time, resulting in the goaf being connected to the overlying old goaf at a close distance, forming an air leakage channel. After on-site investigation and testing, the 3304 working face of A Coal Mining leaked air toward the direction of B Coal Mining (goaf), resulting in insufficient air volume for the 3304 working face of A Coal Mining, and easily causing spontaneous combustion in the goaf, posing a serious safety hazard.

[0074] In order to control the air leakage in the 3304 working face of A Coal Industry, an intelligent control method for goaf air leakage under the interference of multi-fan joint operation is proposed. The specific steps are as follows:

[0075] Step 1: Arrange relevant equipment

[0076] Ultrasonic wind speed sensors 3 were installed every 10 meters in the 3304 air intake tunnel 4 and 3304 return air tunnel 5 on both sides of the 3304 working face of Coal Industry, starting 60 meters from the working face cut. These sensors monitor the air volume in both the air intake and return air tunnels in real time. Methane sensors T0 at the return air corner of the 3304 working face of Coal Industry and methane sensors T1 and T2 in the 3304 return air tunnel 5 were connected to a control box 2. After a field survey revealed air leakage in the goaf of the 3304 working face of Coal Industry, intelligent dampers and windows 1 were installed in the 3304 air intake tunnel 4 to control this leakage. A control box 2 was installed near the intelligent damper and window 1. This control box 2 is connected to the servo motor 9 that controls the window opening, the ultrasonic wind speed sensors 3, and the host computer. The control box 2 transmits the air volume and gas data monitored by the sensors to the host computer.

[0077] Step 2: Set the air leakage rate Q of the working surface 设 , calculate the input variables of the variable universe fuzzy PID control system.

[0078] The host computer calculates the actual air leakage Q in real time based on the data of the ultrasonic wind speed sensor 3 arranged in the 3304 air inlet tunnel 4 and the 3304 return air tunnel 5 实 The air volume of 3304 air inlet lane 4 was monitored to be 1408.37m 3 / min, the air volume of 3304 return air channel 5 is 890.7m 3 / min, that is, the actual air leakage volume Q of the 3304 working face of A Coal Industry 实 517.67m 3 / min. The host computer monitors the gas concentration T0, T1, and T2 to prevent safety accidents caused by excessive gas concentration. According to the actual needs of A Coal Industry, the air leakage rate is set to 200m 3 / min meets the requirements, that is, it is set as the working surface leakage volume Q in the host computer. 设 , the host computer calculates the actual air leakage Q 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c As the input variable of the variable universe fuzzy PID control system.

[0079] Step 3: Output control signal of variable universe fuzzy PID system

[0080] The variable universe fuzzy PID control system input variables calculated by the host computer in step 2 are transmitted to the control box 2. The expansion factor is obtained through the variable universe module, and the expansion factor is used to adjust the initial proportional factor and the initial quantization factor. The three parameters K of PID are obtained through the fuzzy adjustment module. I , K P , K D , the air leakage difference e and the difference change rate e c , KI , K P , K D As the input of the PID controller module, the PID controller module outputs a control signal of the servo motor. The control box 2 receives the control signal and transmits it to the servo motor 9.

[0081] Step 4: Adjust the window area to make the actual air leakage Q 实 Reach the set air leakage Q 设 .

[0082] The servo motor 9 adjusts the size of the air window opening according to the signal transmitted by the control box 2, reducing the air window area, balancing the pressure difference between the goaf 8 of the 30303 working face of B Coal Industry and the goaf 6 of the 3304 working face of A Coal Industry, and reducing the air volume of the 3304 air inlet tunnel 4 to a certain extent. After multiple calculations and adjustments, the air volume of the 3304 air inlet tunnel 4 of A Coal Industry was finally reduced to 890.21m 3 / min, the air volume of 3304 return air channel 5 is 767.32m 3 / min, the air leakage of the 3304 working face of A Coal Industry is reduced to 122.9m 3 / min, and the required air volume of the working face is higher than the minimum required air volume and the gas concentrations T0, T1 and T2 are within the limit, thus achieving the purpose of controlling the air leakage.

[0083] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. An intelligent control method for goaf air leakage under the interference of multiple fans operating in conjunction, characterized by: Sensors are used to monitor air volume and gas concentration in real time. The control box receives the monitoring data from the sensors and feeds it back to the host computer. The host computer calculates the actual air leakage from the working surface to the goaf in real time. The servo motor in the control box controls the window area to adjust the air volume. The host computer makes further instructions based on the adjusted air leakage until the set air leakage requirement is met. The specific steps are as follows: Step 1. Install ultrasonic wind speed sensors in the air intake and return air lanes on both sides of the working face in the goaf's air leakage area. Install smart dampers and windows in the air intake lanes, and install a matching control box near the smart dampers and windows. Step 2. The host computer calculates the actual air leakage Q in real time based on the air volume of the air inlet and return air channels on both sides of the working face. 实 , set the working surface air leakage Q in the host computer according to the working conditions 设 , the host computer calculates the actual air leakage Q in real time 实 and the set working surface air leakage Q 设 The difference e, and the rate of change of the difference e c , and the difference e and the rate of change of the difference e c Transmit to the control box; Step 3. The actual air leakage Q calculated by the host computer 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c Transmitted as input variables to the variable universe fuzzy PID control system in the control box; The scaling factor is obtained through the variable domain module, and the scaling factor adjusts the initial scale factor and the initial quantization factor; The three parameters K of PID are obtained through the fuzzy adjustment module I , K P , K D ; The air leakage difference e and the difference change rate e c , K I , K P , K D As the input variable of the PID controller module, the PID controller module outputs the control signal of the servo motor; Step 4. The servo motor adjusts the airflow area of ​​the damper and window according to the received control signal, changes the air intake, and balances the pressure difference between the monitored goaf and the surrounding goaf until the actual air leakage volume Q 实 Lower than or equal to the set air leakage Q 设 If the upper computer calculates that the air leakage volume does not reach the set value, it will re-enter step 3 and start the calculation until the actual air leakage volume is lower than or equal to the set air leakage volume; The variable universe fuzzy PID control system specifically includes the following contents: S1, let the input variable difference e and the difference change rate e c The initial domains are [-e0, e0], [-e c0 , e c0 ], output variable ΔK P , ΔK I , ΔK D The initial domains are [-K p0 , K p0 ]、[-K i0 , K i0 ]、[-K d0 , K d0 ], and set the input variable difference e and the difference change rate e c And the output variable ΔK P , ΔK I , ΔK D The fuzzy domain of is [-M, M]; S2, the actual air leakage Q 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c As the input variable of the variable universe module, the scaling factor α of the input variable difference e is obtained using the scaling factor function model e , difference change rate e c The expansion factor α ec and three output variables ΔK P , ΔK I , ΔK D The expansion factor β P , β I , β D ; The scaling factor function model is as follows: Enter the scaling factor: Output scaling factor: Where λ∈(0,1),k 0;K I is the proportional factor; P i is the input weight coefficient; is the input variable error; is the initial value of the output universe scaling factor; S3, according to the initial domain and fuzzy domain set in S1, the initial quantization factor K is obtained e0 , K ec0 and the initial scale factor L P0 、L I0 、L D0 ,Right now 、 、 、 、 , the scaling factor α obtained in S2 e , α ec For the initial quantization factor K e0 , K ec0 Adjust to get the quantization factor K e With K ec ,Right now 、 ; Difference e and rate of change of difference e c As the input variable of the fuzzy adjustment module, the fuzzy quantity e is obtained by fuzzification processing through the action of quantization factors. * With e c * ,Right now 、 ; Set fuzzy sets and fuzzy rules with reference to expert domain knowledge and use the center of gravity method to calculate the fuzzy quantity e * With e c * Perform fuzzy processing to obtain the output value ΔK P * , ΔK I * , ΔK D * ; Using the scaling factor β of the output variable P , β I , β D Adjust the initial scale factor to obtain the scale factor L P , L I , L D ,Right now 、 、 ; Output value ΔK P * , ΔK I *, ΔK D * Proportional adjustment is performed on the three proportional factors to obtain the parameter adjustment value ΔK P , ΔK I , ΔK D ,Right now 、 、 ; S4, the initial value K is obtained by the PID controller parameter tuning method P0 , K I0 , K D0 , according to the adjustment amount ΔK obtained above P , ΔK I , ΔK D Adjust the initial value to obtain the three parameters of PID control 、 、 ; The difference e and the rate of change of the difference e c And 3 parameters K P , K I , K D As the input variable of the PID controller module, the PID controller module outputs a control signal that is transmitted to the servo motor; the discretization formula of the PID control algorithm is: Where u n is the output result after adjusting n times, e n The actual air leakage volume Q for the nth time 实 and set air leakage Q 设 Difference, T s To control the time, K P is the proportional constant, T I Integration time constant, T D Differentiation time constant.

2. The intelligent control method for goaf air leakage under the interference of multiple fans in joint operation according to claim 1 is characterized by: The control box is a KXJ127 explosion-proof and intrinsically safe PLC control box for mining. A variable domain fuzzy PID control system is set in the PLC control box. The signal receiving end of the control box is connected to an ultrasonic wind speed sensor for detecting air volume, a methane sensor T0 at the return air corner of the coal mining working face, and two methane sensors in the return air lane of the coal mining working face; the signal output end of the control box is connected to the control end of the servo motor; and the control box and the host computer and the servo motor transmit signals in a two-way manner.

3. The intelligent control method for goaf air leakage under the interference of multiple fans in joint operation according to claim 2 is characterized by: The variable universe fuzzy PID control system of the control box includes a variable universe module, a fuzzy adjustment module and a PID controller module.

4. The intelligent control method for goaf air leakage under the interference of multiple fans in joint operation according to claim 1 or 2 is characterized by: The ultrasonic wind speed sensors are set in the air inlet and return air lanes of the air leakage working face in the goaf. Starting from 60m away from the working face cut eye, a group of ultrasonic wind speed sensors for monitoring the air volume in the air inlet and return air lanes of the air leakage working face are installed at equal intervals in the direction of the goaf, and the number of ultrasonic wind speed sensors on both sides of the air inlet and return air lanes is no less than 3 groups.

5. The intelligent control method for goaf air leakage under the interference of multiple fans in joint operation according to claim 1 is characterized by: In step 2, the host computer calculates the actual air leakage Q in real time. 实 and the set working surface air leakage Q 设 The difference e and the rate of change of the difference e c , the calculation method is as follows: Step 2.1 Assume that the air volume monitored by the ultrasonic wind speed sensor in the air inlet channel is Q 进i , represents the air volume monitored by the i-th sensor. Similarly, the air volume monitored by the ultrasonic sensor in the return air channel is Q 回i , the air volume of the air inlet channel is , where n represents the number of sensors, and the calculation is similar , actual air leakage of the working surface ; Step 2.2 Difference between actual air leakage and set air leakage , the rate of change of difference .

6. The intelligent control method for goaf air leakage under the interference of multiple fans in joint operation according to claim 1 is characterized by: The upper computer sets the minimum required air volume of the working surface, and the return air volume is regarded as the working surface air volume. If the working surface air volume is lower than the minimum required air volume of the working surface, the air leakage volume Q needs to be reset. 设 .

7. The intelligent control method for goaf air leakage under the interference of multiple fans in joint operation according to claim 1 is characterized by: The upper computer sets the minimum required air volume for the working surface. If the air volume on the working surface is lower than the minimum required air volume after adjustment, the air leakage volume Q is reset. 设 The host computer simultaneously monitors the gas concentration data of the return air corner T0 and the return air channel in real time. When the gas concentration data exceeds the limit, the host computer turns on the gas concentration warning, sends a warning instruction to the control box for voice warning, and the control box outputs a control signal to the servo motor to control the intelligent damper-window opening to return to the maximum state. After the gas concentration returns to normal, the leakage volume Q is reset according to the real-time monitored air volume. 设 And ensure that the gas concentration no longer exceeds the limit and continue to adjust.

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