A method for detecting the closing degree of air distributor of a ventilator

Abstract

The present invention relates to a method for detecting the closure degree of an air divider of a ventilator. The method analyzes the characteristics of different baffle layouts through the structural design and layout of the air divider, installs a closure degree adjustment device inside the air divider, adjusts the closure degree of the air divider through the device, detects the number of rotations of a shaft through a rotary encoder, calculates the closure degree of the air divider through a "displacement-closure degree" mathematical model, controls a single brushless DC motor through a cascade PID, and realizes position synchronization between dual motors through a cross-coupling control algorithm, so that the closure degree of the air divider is within a required error range, and realizes automatic detection and control of the closure degree of the air divider through the closure degree adjustment device.

Description

Technical Field

[0001] The invention relates to the field of ventilation of underground mine ventilators, and in particular to a method for detecting the closure degree of an air distributor of a ventilator. Background Art

[0002] Gas is an inevitable harmful gas in the coal mine production process. In addition, coal dust and dust in mines also affect the safety of mine production. Conventional ventilation management systems generally rely on manual operation and control by relevant personnel, which can easily cause safety management loopholes and production safety accidents. Therefore, the intelligence and visualization of the ventilation management system can greatly improve the reliability of the ventilation safety management system, and can minimize the probability of production safety accidents and the consumption of safety management costs. The automatic switching of the local fan air distributor, the on-demand air supply and flexible adjustment lay the foundation for the realization of intelligent ventilation fans. Summary of the invention

[0003] In view of the above problems, the present invention provides a method for detecting the closure degree of a ventilator air distributor, which realizes automatic switching of the local ventilator air distributor, air supply on demand and flexible adjustment of air volume, and realizes the intelligence of the ventilator.

[0004] The present invention provides a method for detecting the closure of an air divider of a ventilator. The method comprises the following steps: by analyzing the characteristics of different layouts of baffles of the air divider through the layout of the baffles, installing a closure adjustment device inside the air divider, and adjusting the closure of the air divider through the device; using a rotary encoder to detect the number of rotations of the shaft, and calculating the closure of the air divider through a displacement-closure mathematical model under ideal conditions; calculating the closure of the air divider through a deflection-closure mathematical model under actual conditions; in the closure adjustment device, a cascade PID algorithm is used to control a single brushless DC motor, and a cross-coupling control algorithm is used to achieve position synchronization between dual motors, so that the closure of the air divider is within the required error range, and automatic detection and control of the closure of the air divider is achieved through the closure adjustment device, thereby achieving precise control of the closure of the air divider of the ventilator. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 It is the overall framework diagram of the system.

[0006] Figure 2 It is a structural schematic diagram of the closure adjustment device.

[0007] Figure 3 It is a cascade PID algorithm.

[0008] Figure 4 It is a position-closure mathematical model diagram.

[0009] Figure 5 It is a deflection-closure mathematical model.

[0010] Figure 6 It is the speed PID control diagram.

[0011] Figure 7 It is the position PID control diagram. DETAILED DESCRIPTION

[0012] The present invention is described in detail below with reference to the accompanying drawings.

[0013] 1. System overall framework

[0014] like Figure 1 As shown, a ventilator air distributor closure degree detection system is provided, and the system comprises: a monitoring layer, a control layer, an execution layer, and a detection layer.

[0015] The detection layer includes a gas sensor, a carbon dioxide sensor, an air volume sensor, a wind speed sensor, an infrared camera and a rotary encoder, which collects the gas content, carbon dioxide content, air volume and wind speed of the excavation working face in real time, identifies personnel, detects the telescopic distance of the telescopic rod in the closure adjustment device, and transmits relevant information to the PLC controller of the control layer, so as to realize online monitoring of the gas content, carbon dioxide content, air volume, wind speed, explosive consumption and number of personnel.

[0016] The control layer includes multiple types of PLC controllers, which receive the sensor data detected by the detection layer and feed them back to the monitoring layer; at the same time, they receive the command signal issued by the monitoring layer, control the closing degree adjustment device through the position PID controller, speed PID controller, and current PID controller, and send control signals to the execution layer.

[0017] The execution layer includes a closure adjustment device, which receives a control signal from the control layer, completes the adjustment of the closure adjustment device, and finally makes the air distributor meet the closure requirement, thereby adjusting the air volume of the working surface.

[0018] The monitoring layer includes a tunneling working face working condition parameter monitoring module and a database interface module; the tunneling working face working condition parameter monitoring module is used to receive the sensor data transmitted by the control layer; the database interface module is used for tunneling working face staff to upload explosive consumption data.

[0019] The monitoring layer calculates the required air volume according to the sensor data transmitted by the control layer in accordance with the requirements of the excavation working face; calculates the required closure degree according to the relationship between the local fan air volume and closure degree; and sends a command signal to the control layer.

[0020] like Figure 2As shown, the closing degree adjustment device is composed of a gear 1, a rack 2, a telescopic rod 3, a sleeve 4, and two brushless DC motors. The rack 2 is fixed on the inner side of the sleeve 4, the gear 1 is meshed with the rack 2 and the telescopic rod 3, the telescopic rod 3 is fixed in the sleeve 4, and the two brushless DC motors drive the gear 1 to rotate. The movement of the telescopic rod 3 is achieved through the meshing action between the gear 1 and the rack 2 fixed on the sleeve 4 and the gear 1 and the telescopic rod 3.

[0021] 2. Layout of baffles

[0022] There are two ways to install the baffle in the air divider: installing the baffle at the two air duct openings and installing the baffle in the main air duct. The air divider controls the opening and closing degree of the baffle to achieve the size of the air divider closure.

[0023] 1. Install baffles at the two air duct openings

[0024] Baffles are installed at the two air duct openings of the air distributor respectively, and the two baffles can be controlled independently, which can effectively adjust the air volume, reduce the loss of air volume and improve the ventilation efficiency.

[0025] 2. Install a baffle on the main air duct of the air distributor

[0026] The baffle is installed in the main air duct of the air distributor. The ventilation volume is adjusted by controlling the opening and closing degree of a baffle. This layout can effectively adjust the air volume, but the wind pressure on the baffle is relatively large, the air volume will deviate, and there will also be air leakage.

[0027] 3. A method for detecting the closure of a fan air divider, by analyzing the layout of the air divider baffles and the characteristics of different baffle layouts, a closure adjustment device is installed inside the air divider, and the closure of the air divider is adjusted by the device; a rotary encoder is used to detect the number of rotations of the shaft, and the closure of the air divider is calculated by the "displacement-closure" mathematical model under ideal conditions; in actual conditions, the closure of the air divider is calculated by the "deflection-closure" mathematical model. In the closure adjustment device, a cascade PID algorithm is used to control a single brushless DC motor, and a cross-coupling control algorithm is used to achieve position synchronization between the dual motors, so that the closure of the air divider is within the required error range. The closure adjustment device realizes automatic detection and control of the closure of the air divider, and realizes precise control of the closure of the fan air divider.

[0028] 4. Cascade PID algorithm, such as Figure 3 As shown, the following steps are included:

[0029] Step 1: The deviation signal Δθ between the desired closing degree and the actual closing degree of the air divider is input as an input signal;

[0030] Step 2: Use Δθ as the input of the position PID controller, and the output is the desired angular velocity ω of the motor;

[0031] Step 3: The deviation signal Δω between the desired angular velocity and the actual angular velocity of the motor is used as the input of the speed PID controller, and the output is the desired current control signal of the motor driver;

[0032] Step 4: Using the deviation signal ΔI between the desired current control signal of the motor driver and the actual current control signal as the input of the current PID controller, the output is the current control signal of the motor driver;

[0033] Step 5: Input the current control signal of the motor driver to the motor driver, and the motor driver drives the motor to operate;

[0034] Step 6: The operation of the motor drives the gear of the closing degree adjustment device to rotate, changing the extension amount of the telescopic rod and feeding back the current signal at the same time;

[0035] Step 7: The rotary encoder detects the number of revolutions of the motor, and calculates and feeds back the angular velocity of the motor and the displacement of the telescopic rod;

[0036] Step 8: The current signal I fed back from step 6 t The current error signal is obtained by comparing the feedback current signal I t After calculating the angular velocity, the actual angular velocity signal ω is obtained. t , the actual angular velocity signal ω t The feedback is compared with the expected angular velocity signal to obtain an angular velocity error signal; the feedback current signal I t Solve the displacement-closure mathematical model to obtain the actual closure signal θ t , the actual closure signal θ t Comparing with the expected closure signal to obtain a closure error signal;

[0037] Step 9: Subtract the motor positions obtained by the two rotary encoders to obtain the error of the two motor positions. The compensation coefficient is calculated by the cross-coupling controller and then transmitted to the position PID controller to ensure the synchronization of the dual motors.

[0038] Step 10: Repeat steps 3 to 9 until the current error signal, the angular velocity error signal and the closing error signal are 0, and then end the process.

[0039] 5. Build a "-closure" mathematical model:

[0040] (1) Mathematical model 1: Modeling idea: Different lengths of the closing adjustment device correspond to different angles, so as to realize the size of the closing degree of the air divider.

[0041] Assuming that the closure adjustment device is in an ideal state, the "displacement-closure" mathematical model is constructed as follows:

[0042] S=N×L (1)

[0043]

[0044] In the formula, S is the telescopic amount of the telescopic rod; N is the number of rotations of the rotary encoder; L is the circumference of the gear indexing circle; a is the distance from the rotating shaft on the damper mechanism to the telescopic rod; b is the distance from the rotating shaft on the baffle to the telescopic rod; l is the minimum length of the telescopic rod.

[0045] (2) Mathematical model 2: Modeling idea: According to the wind pressure of the fan, calculate the force on one end of the closing adjustment device, and analyze F through the graphical method. 风 The relationship between F′, β, l, W and θ can be used to determine the degree of closure of the air distributor.

[0046] Assuming that the closure adjustment device is under stress, the "deflection-closure" mathematical model is constructed as follows:

[0047] F 风 =PS=242.08N (3)

[0048] Among them, P is the wind pressure, which is 762Pa; S is the cross-sectional area of ​​the wind duct.

[0049] F′=F 风 ×sinβ (4)

[0050]

[0051] Among them, F' is the longitudinal component of wind force, β is the angle between wind force and horizontal direction, and l is the length of the closure adjustment device.

[0052]

[0053] Wherein, W is the deflection of the closure adjustment device; E is the elastic modulus of steel; and I is the section moment of inertia of steel.

[0054] The deflection-closure mathematical model obtained from equations (3), (4), (5), and (6) is as follows:

[0055]

[0056] 6. Simulation Experiment

[0057] The simulation software MATLAB2018 / Simulink is used to simulate the air distributor closure detection system, build a simulation experimental platform and set relevant parameters. The experimental platform mainly includes: input signal, position PID control, speed PID control, current PID control, SVPWM module, stepper motor, encoder, oscilloscope. Through the dynamic adjustment of current, speed and position, the experimental platform reaches a stable state and completes the control and detection of the air distributor closure.

[0058] from Figure 6 , Figure 7 It can be concluded that when using cascade PID to control the stepper motor, its acceleration and deceleration process is relatively stable, and the position curve changes smoothly; compared with manual adjustment, the overshoot of cascade PID is smaller, and the speed curve is in an ideal state; at the same time, the cascade PID position control effect is significant and very close to the ideal state.

Claims

1. A method for detecting the closure degree of a fan air distributor, Its characteristics are By analyzing the layout of the air divider baffles and the characteristics of different baffle layouts, a closure adjustment device is installed inside the air divider, and the closure of the air divider is adjusted through the closure adjustment device; a rotary encoder is used to detect the number of rotations of the shaft; under ideal conditions, the closure of the air divider is calculated through a displacement-closure mathematical model; under actual conditions, the closure of the air divider is calculated through a deflection-closure mathematical model; in the closure adjustment device, a cascade PID algorithm is used to control a single brushless DC motor, and a cross-coupling control algorithm is used to achieve position synchronization between two brushless DC motors, so that the closure of the air divider is within the required error range, and the closure adjustment device realizes automatic detection and control of the closure of the air divider, and realizes precise control of the closure of the fan air divider; Under ideal conditions, the process of building a displacement-closure mathematical model is as follows: S=N×L (1) In the formula, S is the telescopic amount of the telescopic rod; N is the number of rotations of the rotary encoder; L is the circumference of the gear indexing circle; a is the distance from the rotating shaft on the damper mechanism to the telescopic rod; b is the distance from the rotating shaft on the baffle to the telescopic rod; l is the minimum length of the telescopic rod; Assuming that the closure adjustment device is under stress, the process of building the deflection-closure mathematical model is as follows: F 风 =PS=242.08N (3) Among them, P is the wind pressure, which is 762Pa, and S is the cross-sectional area of ​​the wind tube. F′=F 风 ×sinβ (4) Among them, F' is the longitudinal component of wind force, β is the angle between wind force and horizontal direction, l is the length of the closing adjustment device, Wherein, W is the deflection of the closing adjustment device, E is the elastic modulus of steel, I is the section moment of inertia of steel, The deflection-closure mathematical model obtained from equations (3), (4), (5), and (6) is as follows:

2. A method for detecting the closure degree of a fan air distributor according to claim 1, Its characteristics are: The cascade PID algorithm comprises the following steps: Step 1: The deviation signal Δθ between the desired closing degree and the actual closing degree of the air divider is input as an input signal; Step 2: Use Δθ as the input of the position PID controller, and the output is the desired angular velocity ω of the motor; Step 3: The deviation signal Δω between the desired angular velocity and the actual angular velocity of the motor is used as the input of the speed PID controller, and the output is the desired current control signal of the motor driver; Step 4: Using the deviation signal ΔI between the desired current control signal of the motor driver and the actual current control signal as the input of the current PID controller, the output is the current control signal of the motor driver; Step 5: Input the current control signal of the motor driver to the motor driver, and the motor driver drives the motor to operate; Step 6: The operation of the motor drives the gear of the closing degree adjustment device to rotate, changing the extension amount of the telescopic rod and feeding back the current signal at the same time; Step 7: The rotary encoder detects the number of revolutions of the motor, and calculates and feeds back the angular velocity of the motor and the displacement of the telescopic rod; Step 8: Convert the current signal I fed back from step 6 t The current error signal is obtained by comparing the feedback current signal I t After calculating the angular velocity, the actual angular velocity signal ω is obtained. t , the actual angular velocity signal ω t The feedback is compared with the expected angular velocity signal to obtain an angular velocity error signal; the feedback current signal I t Solve the displacement-closure mathematical model to obtain the actual closure signal θ t , compare the actual closure signal θ with the expected closure signal to obtain a closure error signal; Step 9: Subtract the motor positions obtained by the two rotary encoders to obtain the error of the two motor positions. The compensation coefficient is calculated by the cross-coupling controller and then transmitted to the position PID controller to ensure the synchronization of the dual motors. Step 10: Repeat steps 3 to 9 until the current error signal, the angular velocity error signal and the closing error signal are 0, and then end the process.

Images