Control method of chain tension self-adjusting system for heavy-duty scraper conveyor

Abstract

This invention relates to a chain tension self-adjusting system and control method for heavy-duty scraper conveyors. The system includes a sprocket with cavities evenly arranged radially. The cavities are filled with damping particles, with a filling rate of 50-60%. The sprocket is equipped with a baffle for sealing the cavities. The damping particles, cavities, and baffles constitute a particle resistance structure. Laser displacement sensors for detecting the vibration signals of the sprocket in the horizontal and vertical directions are installed on the telescopic tail of the heavy-duty scraper conveyor, aligned with the center point of the sprocket. This forms a hybrid active and passive damping mode, which can effectively suppress the vibration of the sprocket and adjust the chain tension to keep it within a safe threshold.

Description

Technical Field

[0001] This invention relates to the field of scraper conveyors for mining, and specifically to a control method for a chain tension self-adjusting system of a heavy-duty scraper conveyor. Background Technology

[0002] Scraper conveyors are key equipment in fully mechanized coal mining faces, and their reliable, stable, and efficient operation directly affects the safety and production capacity of modern coal mines. Scraper conveyors operate in harsh environments with numerous uncertainties and significant random vibrations and impacts. The scraper chain is the component that most directly bears the load of falling coal. When subjected to the impact of falling coal, the chain becomes compressed and taut, leading to increased chain tension. This causes strong vibrations in the tail sprocket, resulting in slack or even chain accumulation at the separation point of the drive sprocket, leading to accidents such as chain drop, jamming, and breakage. Suppressing sprocket vibration has become a current research focus. Particle damping vibration reduction technology, since its inception, has been widely used in aviation, aerospace, machinery, and civil engineering. It can still work well in harsh environments, is almost unaffected by temperature, and does not suffer from problems such as material degradation and fatigue effects. Furthermore, it has a wide damping frequency range, low cost, and strong recovery capability. Particle dampers mainly rely on the contact collision and energy dissipation between damping particles and the damper for vibration reduction, resulting in significant vibration reduction effects. Currently, the main method for reducing sprocket vibration in practical applications is active vibration reduction by adjusting chain tension through the telescopic tail. However, most of these methods rely on directly measuring chain tension using tension sensors. In harsh working environments, tension sensors are susceptible to numerous interference factors, leading to large errors and low reliability, thus reducing the adjustment effect. Therefore, it is urgent to solve the problems of how to reduce sprocket vibration using particle damping technology and how to use a reliable information-controlled chain tension adjustment system to optimize the design of vibration reduction devices for scraper conveyors. Summary of the Invention

[0003] This invention proposes a control method for a self-adjusting chain tension system for heavy-duty scraper conveyors.

[0004] A heavy-duty scraper conveyor chain tension self-adjusting system includes a sprocket with cavities evenly arranged radially. These cavities are filled with damping particles, with a particle filling rate of 50-60%. A baffle is installed on the sprocket to seal the cavities. The damping particles, cavities, and baffle constitute a particle resistance device structure. Laser displacement sensors for detecting the vibration signals of the sprocket in the horizontal and vertical directions are installed on the tail of the heavy-duty scraper conveyor, aligned with the center point of the sprocket.

[0005] Preferably, the sprocket has six cavities evenly arranged radially.

[0006] Preferably, the damping particles are steel ball particles and rubber particles, and the ratio of steel ball particles to rubber particles is 1:1.

[0007] Preferably, the vibration signal includes the vibration displacement, vibration velocity, and vibration acceleration of the sprocket.

[0008] Preferably, the heavy-duty scraper conveyor is equipped with two laser displacement sensors at its tail, which are used to detect the vibration information of the sprocket in the horizontal and vertical directions, respectively.

[0009] This invention also provides a control method for the above system, specifically including:

[0010] (1) The resistance generated by the particle resistance structure on the sprocket is divided into horizontal resistance and vertical resistance, denoted as F. x (δ) represents the horizontal contact force between the damping particles and the inner wall of the sprocket cavity, i.e., the horizontal resistance. y (δ) represents the contact force between the damping particles and the inner wall of the sprocket cavity in the vertical direction, i.e., the vertical resistance. The horizontal resistance F... x (δ) and vertical resistance F y Substituting (δ) into the vibration control equation of the chain drive system, the following equation is obtained to verify the rationality of the particle resistance device structural design:

[0011]

[0012] Where: c1 is the damping coefficient of the sprocket and bearing in the horizontal direction, c2 is the damping coefficient of the sprocket and bearing in the vertical direction, k1 is the stiffness coefficient of the sprocket and bearing in the horizontal direction, k2 is the stiffness coefficient of the sprocket and bearing in the vertical direction, is the vibration excitation of the sprocket in the horizontal direction, x, These represent the horizontal vibration displacement, vibration velocity, and vibration acceleration of the sprocket, respectively. These represent the vertical vibration displacement, vibration velocity, and vibration acceleration of the sprocket, respectively; m is the mass of the sprocket.

[0013] (2) After verification, before the chain tension self-adjustment system of the heavy scraper conveyor is put into operation, the horizontal vibration threshold X and vertical vibration threshold Y of the sprocket are set according to the no-load and full-load conditions of the scraper conveyor.

[0014] (3) Determine whether the horizontal and vertical vibration signals of the sprocket collected by the laser displacement sensor are within the set vibration safety threshold X and vertical vibration threshold Y ranges. The specific determination method is as follows:

[0015] (31) The collected vibration signal value is less than the set vibration threshold, indicating that the vibration is small. The industrial control computer of the heavy-duty scraper conveyor outputs an unexceeded signal, and the chain tension self-regulation control system is silent, that is, the chain tension is not adjusted. Specifically, it includes: using a laser displacement sensor to collect the vibration signals of the sprocket wheel in the horizontal and vertical directions, including vibration displacement, vibration velocity and vibration acceleration. The collected vibration signals are preprocessed, and the processed vibration signal values are compared with the pre-set horizontal vibration threshold X and vertical vibration threshold Y. If the collected vibration signal value is less than the set vibration threshold, it is considered that the vibration is within the safe range, and the chain tension is not adjusted. The specific judgment formula is: V x <X and V y <Y, where: V x is the vibration signal value in the horizontal direction, V y is the vibration signal value in the vertical direction, X is the horizontal vibration threshold, and Y is the vertical vibration threshold;

[0016] (32) The collected vibration signal is greater than the set vibration threshold, indicating that the vibration of the sprocket wheel is too large. The industrial control computer of the heavy-duty scraper conveyor will output a judgment signal that the vibration of the sprocket wheel of the scraper conveyor is too large. The specific judgment formula is: V x >X or V y >Y, where: Vx is the vibration signal value in the horizontal direction, Vy is the vibration signal value in the vertical direction, X is the horizontal vibration threshold, and Y is the vertical vibration threshold;

[0017] (4) The upper computer of the heavy-duty scraper conveyor receives the judgment signal that the vibration of the sprocket wheel sent by the industrial control computer of the heavy-duty scraper conveyor, and obtains the real-time chain tension information through the following formula:

[0018]

[0019] In the formula: F x is the lateral meshing force of the meshing part of the wheel chain link; F y is the longitudinal meshing force of the meshing part of the wheel chain link; F t is the meshing resultant force; force; T O1 is the chain tension of the first flat link; T O2 is the chain tension of the second flat link; T O3 is the chain tension of the third flat link; α is the meshing angle of the second flat link; θ is the meshing angle of the third flat link; β is the meshing angle of the fourth flat link;

[0020] (5) According to the magnitude of the meshing resultant force, control the servo valve of the heavy-duty scraper conveyor to work to loosen or tighten the chain, thereby reducing the vibration of the sprocket wheel; specifically, it includes: presetting the meshing resultant force safety threshold F safe , if F t <F safeThe system will increase the pressure of the hydraulic cylinder through the servo valve to tension the chain; if F t >F safe The system will reduce the pressure in the hydraulic cylinder through a servo valve, causing the chain to loosen.

[0021] Preferably, the host computer of the heavy-duty scraper conveyor communicates with the industrial control computer of the heavy-duty scraper conveyor via Ethernet, using the TCP / IP protocol for bidirectional data transmission. The industrial control computer of the heavy-duty scraper conveyor is equipped with two PCI-1716 analog signal acquisition cards, one PCI-1784 digital signal acquisition card, one PCI-6208 driver card, a network card, and an xPC real-time kernel. The PCI-1716 analog signal acquisition card, PCI-1784 digital signal acquisition card, PCI-6208 driver card, network card, and xPC real-time kernel are connected to the PCI slots of the industrial control computer and are powered by the industrial control computer's power supply. The signal conditioning box contains four analog signal conditioning cards. The system includes a current-driven conditioning board and a sensor power supply module. The analog conditioning board converts the 4-20mA current signals from the laser displacement sensor, hydraulic sensor, displacement sensor, and tension / compression sensor of the heavy-duty scraper conveyor into a -10V-10V voltage signal that can be acquired by the PCI-1716 A / D board. The PCI-6208 driver board converts the digital signal calculated by the fuzzy self-tuning PID controller into a -10V-10V voltage signal, which is then converted into a -40mA-40mA current signal by the signal conditioning system to drive the servo valve. The signal is then output to the tensioning hydraulic cylinder of the heavy-duty scraper conveyor to adjust the chain tension and achieve vibration reduction.

[0022] Preferably, the calculation formula for the fuzzy self-tuning PID controller of the industrial control computer is as follows:

[0023]

[0024] ΔF=F t -F safe ;

[0025] In the formula: Ft is the meshing force; F safe K represents the safe threshold for meshing force. P '、K I 'and K D 'They are K' P ,K I ,K D Initial parameters; G P G I G D ΔK is the correction value, and ΔK is a constant. P ΔK I ΔK D They are K PK I K D The values ​​obtained through fuzzy reasoning; the changing pressure value required for ΔF elongation; K P ,K I ,K D These are the proportional, integral, and derivative gains, respectively, and U is the controller output.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. This invention reduces the vibration experienced by the sprocket of the scraper conveyor during operation by placing particle damping through an open cavity in the sprocket. The damping particles absorb the energy of the sprocket vibration, thereby passively reducing the vibration and increasing the stability of the sprocket.

[0028] 2. This invention proposes to obtain vibration information of the sprocket using a laser displacement sensor to determine whether the chain tension needs to be adjusted, and to determine the tightness of the chain by the magnitude of the meshing force between the sprocket and the chain link, which can improve the accuracy and stability of chain tension control.

[0029] 3. This invention uses a telescopic tail section to change the center distance between the head and tail sections to adjust the chain tension through a chain tension self-control system. This forms a hybrid active and passive damping mode, which can effectively suppress the vibration of the sprocket caused by abnormal chain tension and adjust the chain tension to keep it within a safe threshold. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the heavy-duty scraper conveyor of the present invention.

[0031] Figure 2 This is a schematic diagram of the sprocket structure of the present invention.

[0032] Figure 3 This is a hardware flowchart of the chain tension self-control system of the present invention.

[0033] Figure 4 This is a flowchart of the control strategy for the chain tension self-control system of the present invention.

[0034] Figure 5 This is a diagram showing the meshing vibration analysis of the chain drive system of the present invention.

[0035] Figure 6 This is a diagram illustrating the sprocket and chain meshing process of the present invention.

[0036] In the diagram: 1-Sprocket, 1-1. Steel ball, 1-2. Rubber ball, 1-3. Baffle, 1-4. Screw hole, 1-5. Deep groove ball bearing, 2. Laser displacement sensor one, 3. Laser displacement sensor two, 4. Telescopic tail, 5. Tension / compression sensor, 6. Servo valve, 7. Displacement sensor, 8. Hydraulic pressure sensor, 9. Servo hydraulic cylinder, 10. Coal mining machine, 11. Random coal drop, 12. Host computer, 13. Industrial computer, 14. Signal conditioning box, 15. Reaction seat. Specific implementation methods

[0037] To make the objectives, technical solutions, and optimizations of this embodiment clearer and more explicit, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0038] like Figure 1-6 As shown in the figure, this embodiment provides a control method for a chain tension self-adjusting system of a heavy-duty scraper conveyor.

[0039] A heavy-duty scraper conveyor chain tension self-adjusting system includes a sprocket with cavities evenly arranged radially. These cavities are filled with damping particles, with a particle filling rate of 50-60%. A baffle is installed on the sprocket to seal the cavities. The damping particles, cavities, and baffle constitute a particle resistance device structure. Laser displacement sensors for detecting the vibration signals of the sprocket in the horizontal and vertical directions are installed on the tail of the heavy-duty scraper conveyor, aligned with the center point of the sprocket.

[0040] Preferably, the sprocket has six cavities evenly arranged radially.

[0041] Preferably, the damping particles are steel ball particles and rubber particles, and the ratio of steel ball particles to rubber particles is 1:1.

[0042] Preferably, the vibration signal includes the vibration displacement, vibration velocity, and vibration acceleration of the sprocket.

[0043] Preferably, the heavy-duty scraper conveyor is equipped with two laser displacement sensors at its tail, which are used to detect the vibration information of the sprocket in the horizontal and vertical directions, respectively.

[0044] This invention also provides a control method for the above system, specifically including:

[0045] (1) The resistance generated by the particle resistance structure on the sprocket is divided into horizontal resistance and vertical resistance, denoted as F. x (δ) represents the horizontal contact force between the damping particles and the inner wall of the sprocket cavity, i.e., the horizontal resistance. y (δ) represents the contact force between the damping particles and the inner wall of the sprocket cavity in the vertical direction, i.e., the vertical resistance. The horizontal resistance F... x(δ) and vertical resistance F y Substituting (δ) into the vibration control equation of the chain drive system, the following equation is obtained to verify the rationality of the particle resistance device structural design:

[0046]

[0047] Where: c1 is the damping coefficient of the sprocket and bearing in the horizontal direction, c2 is the damping coefficient of the sprocket and bearing in the vertical direction, k1 is the stiffness coefficient of the sprocket and bearing in the horizontal direction, k2 is the stiffness coefficient of the sprocket and bearing in the vertical direction, is the vibration excitation of the sprocket in the horizontal direction, x, These represent the horizontal vibration displacement, vibration velocity, and vibration acceleration of the sprocket, respectively. These represent the vertical vibration displacement, vibration velocity, and vibration acceleration of the sprocket, respectively; m is the mass of the sprocket.

[0048] (2) After verification, before the heavy-duty scraper conveyor chain tension self-adjustment system is put into operation, the horizontal vibration threshold X and vertical vibration threshold Y of the sprocket are set according to the no-load and full-load conditions of the scraper conveyor. Before setting the thresholds, the sprocket vibration data of the heavy-duty scraper conveyor under no-load and full-load conditions are collected. Data including vibration displacement, vibration velocity and vibration acceleration are collected by two laser displacement sensors (laser displacement sensor 12 and laser displacement sensor 23) installed on the sprocket. The collected data are statistically analyzed to determine the distribution characteristics of sprocket vibration under no-load and full-load conditions, including the mean, standard deviation, maximum and minimum values. The set thresholds X and Y are based on the data analysis results, taking into account the balance between safety and efficiency. The thresholds are set to be more than 95% of the vibration data under full load conditions to ensure that the sprocket is in most cases. The vibration will not exceed this value. When setting the actual threshold, a safety factor of 1.1-1.3 is introduced. The actual threshold is 10% to 30% higher than the value obtained from data analysis to provide a certain safety margin. In this embodiment, the safety factor is 1.2. In this embodiment, the average vertical vibration acceleration of the sprocket under full load is 0.5g, the standard deviation is 0.2g, and the maximum value is 1.2g; the average horizontal vibration acceleration is 0.5g, the standard deviation is 0.2g, and the maximum value is 1.0g. The threshold is set as follows: Vertical vibration threshold Y: take the maximum value of 1.2g multiplied by the safety factor 1.2 to get the vertical vibration threshold Y = 1.2g * 1.2 = 1.44g. Horizontal vibration threshold X: the maximum value of horizontal vibration is 1.0g, multiplied by the safety factor 1.2 to get the horizontal vibration threshold X = 1.0g * 1.2 = 1.2g.

[0049] (3) Determine whether the horizontal and vertical vibration signals of the sprocket collected by the laser displacement sensor are within the set vibration safety threshold X and vertical vibration threshold Y ranges. The specific determination method is as follows:

[0050] (31) The collected vibration signal value is less than the set vibration threshold, indicating that the vibration is small. The industrial control computer of the heavy-duty scraper conveyor outputs an over-limit signal, and the chain tension self-regulation control system is silent, that is, the chain tension is not adjusted. Specifically, it includes: using a laser displacement sensor to collect the vibration signals of the sprocket wheel in the horizontal and vertical directions, including vibration displacement, vibration velocity, and vibration acceleration. The collected vibration signals are preprocessed, and the processed vibration signal values are compared with the pre-set horizontal vibration threshold X and vertical vibration threshold Y. If the collected vibration signal value is less than the set vibration threshold, it is considered that the vibration is within the safe range, and the chain tension is not adjusted. The specific judgment formula is: Vx < X and Vy < Y, where: Vx is the vibration signal value in the horizontal direction, Vy is the vibration signal value in the vertical direction, X is the horizontal vibration threshold, and Y is the vertical vibration threshold;

[0051] (32) The collected vibration signal is greater than the set vibration threshold, indicating that the vibration of the sprocket wheel is too large. The industrial control computer of the heavy-duty scraper conveyor will output a judgment signal that the vibration of the sprocket wheel of the scraper conveyor is too large. The specific judgment formula is: Vx > X or Vy > Y, where: Vx is the vibration signal value in the horizontal direction, Vy is the vibration signal value in the vertical direction, X is the horizontal vibration threshold, and Y is the vertical vibration threshold;

[0052] (4) The upper computer of the heavy-duty scraper conveyor receives the judgment signal that the vibration of the sprocket wheel sent by the industrial control computer of the heavy-duty scraper conveyor; during the meshing transmission of the sprocket wheel and the chain, due to the existence of dynamic loads, impact loads during meshing and the influence of the polygon effect, the force condition and force characteristics in the meshing area are relatively complex, which causes the vibration of the tail device of the scraper conveyor. To analyze the meshing vibration of the sprocket wheel and the chain, it is necessary to analyze the meshing force of the sprocket wheel and the chain; the analysis of the meshing and disengaging points of the chain and the tail sprocket wheel is as shown in the appendix Figure 5 as shown;

[0053] During the meshing transmission of the sprocket wheel and the chain, due to the existence of dynamic loads, impact loads during meshing and the influence of the polygon effect, the force condition and force characteristics in the meshing area are relatively complex, which causes the vibration of the tail device of the scraper conveyor; taking a five-tooth sprocket wheel rotating clockwise as an example, during the movement process, mainly three flat rings contact with the sprocket wheel, and the chain tension of the flat ring is approximately equal to the meshing force generated by contacting the sprocket wheel. To analyze the meshing vibration of the sprocket wheel and the chain, it is necessary to analyze the meshing force of the sprocket wheel and the chain; the analysis of the meshing and disengaging points of the chain and the tail sprocket wheel is as shown in the appendix Figure 5 as shown;

[0054] Considering the meshing process of chain drive, the scraper chain loops around the sprocket in a polygonal pattern. When the tail drive operates at a constant angular velocity, the scraper chain's speed and load fluctuate due to the polygonal effect. To describe this fluctuation, based on the NMC model (NMC refers to the Neural Marching Cubes model well-known to those skilled in the art, which uses deep learning to predict the boundaries of each cube using a neural network and generates continuous surfaces using an efficient octree structure; this is a deep learning-based 3D reconstruction technique), the height distance between the engagement and disengagement points of the sprocket chain is expressed as follows:

[0055]

[0056] In the formula: R0 is the pitch circle radius of the tail sprocket, α0 and β are the engagement and disengagement angles of the sprocket and chain links; h O1 and h OC These are the vertical distances from the engagement point and the geometric center of the sprocket to the bottom plate of the central groove, respectively; h B and h OD These are the vertical distances from the engagement point and the geometric center of the sprocket to the middle plate of the central groove, respectively; in this embodiment, the central groove is the vertical groove of the sprocket.

[0057] The unloaded side chain is suspended under the support of the central trough bottom plate, according to... Figure 5 From the information, the suspension tension at point C can be obtained as follows:

[0058] T C =8λgh 3 O1 / 9(S2-L) 2

[0059] In the formula: λ is the mass per unit length of the chain; g is the acceleration due to gravity; S2 is the length of the unloaded side of the chain; L is the center distance between the head sprocket and the tail sprocket.

[0060] The motor drives the sprocket to rotate clockwise at a certain angular velocity, and the meshing force drives the chain links to move, realizing the meshing process of the chain drive system. According to the meshing contact of the sprocket and chain, the meshing process is divided into three stages: engagement, disengagement, and engagement. This embodiment uses a clockwise rotating five-tooth sprocket as an example; the meshing process is shown in the attached figure. Figure 6As shown; during the meshing stage, when the arc segment O1 of the second flat ring initially contacts the sprocket tooth surface, the corresponding meshing angle is α0. The sprocket continues to rotate, and the vertical ring and sprocket enter the meshing stage. When the arc segment O1 of the second flat ring coincides with the center of the chain groove, the second flat ring completes the meshing process with the sprocket. As the vertical ring enters the vertical groove of the sprocket, and the arc segment of the zero flat ring aligns with the meshing center of the chain groove on the back of the sprocket tooth, the vertical ring meshes with the sprocket. Subsequently, the sprocket continues to rotate clockwise, and the zero flat ring is pulled towards the chain by the traction force of the vertical ring. The movement is in the direction of the sprocket; when the arc segment O0 of the flat ring zero contacts the tooth surface of the sprocket, it marks the end of a complete meshing cycle; the meshing process of flat ring three, flat ring four and the corresponding vertical ring is the same as that of flat ring two; the range of meshing angle variation between the arc segment O1 of flat ring two and the arc segment O2 of flat ring three is 2π / z, z=5, flat ring four is on the loaded side, and it is approximately in a straight line state due to the tension force, the meshing angle of flat ring four is approximately the meshing angle β of the disengagement point; it can be obtained that the meshing angle of the corresponding meshing point in the above meshing process is:

[0061]

[0062] In the formula: S1 is the length of the loaded side chain; α is the meshing angle of the second flat ring; θ is the meshing angle of the third flat ring; w S ω is the angular velocity of the sprocket rotation; T is the meshing period; L is the center distance between the head sprocket and the tail sprocket; n represents a natural number; and t is the sprocket rotation time.

[0063] When the sprocket rotates, T B T represents the chain tension when the chain separates from the sprocket at the tail end of the machine, approximately equal to the chain pretension; O1 T1 is the chain tension at the tail end when the chain and sprocket just engage; T2 is the chain tension at the head end when the chain and sprocket separate; and T3 is the chain tension at the head end when the chain and sprocket just engage. Ignoring the effects of time-varying meshing friction and centrifugal force between the sprocket and chain links, and based on the principle of point-by-point tension calculation, the stress between each chain link has a linear relationship, and the following expression can be used to calculate T. O1 :

[0064]

[0065] In the formula: W U The running resistance of the loaded side of the central tank; W D The running resistance of the unloaded side of the central tank; k f k is the resistance coefficient for material movement in the chute. u Let k be the coefficient of resistance to movement between the loaded chain and the central groove. u =0.3; k d Let k be the coefficient of resistance to movement between the unloaded side chain and the central groove. d=0.5; q is the resistance coefficient of the coal moving in the chute; λ is the mass per unit length of the chain; L is the center distance between the head sprocket and the tail sprocket; g is the acceleration due to gravity. Similarly, T O2 and T O3 The calculation principle and T O1 The same applies; based on the data obtained from the above formula, and combined with the changes in the meshing angle at each meshing point during the sprocket rotation, the lateral meshing force F of the meshing transmission system is calculated. x Longitudinal meshing force F y Meshing force F t With meshing force F t Safety threshold F of meshing force safe The chain tension is determined by comparison using the following formula:

[0066] The real-time chain tension information can be obtained using the following formula:

[0067]

[0068] In the formula: F x F is the lateral meshing force of the chain link engagement section; y F is the longitudinal meshing force of the chain ring meshing part; t For meshing force; T O1 The chain tension of the flat ring; T O2 T is the chain tension of the flat ring II; O3 α is the chain tension of the third flat ring; α is the meshing angle of the second flat ring; θ is the meshing angle of the third flat ring; β is the meshing angle of the fourth flat ring.

[0069] Based on the magnitude of the meshing force, the servo valve of the heavy-duty scraper conveyor is controlled to loosen or tighten the chain, thereby reducing sprocket vibration; specifically, this includes: setting a preset meshing force safety threshold F. safe If F t <F safe The system will increase the pressure of the hydraulic cylinder through the servo valve to tension the chain; if F t >F safe The system will reduce the pressure in the hydraulic cylinder through a servo valve, causing the chain to loosen.

[0070] This embodiment uses a preset meshing force safety threshold F. safe At the same time, data on meshing force changes under different conditions are collected to adjust and verify the safety threshold; the specific meshing force safety threshold F safe The determination includes determining the following parameters: minimum safe meshing force F min Maximum safe meshing force F max Operating meshing force, i.e., the currently measured meshing force F. opSafety factor S, where S is greater than 1; meshing force safety threshold F. safe The range can be determined by the following formula: F min =F op *SF max =F op *S; where F op It is the operating engagement force that a person skilled in the art can obtain through experimentation or calculation under specific load and speed conditions, and S is the safety factor that a person skilled in the art can determine based on experience and safety requirements.

[0071] Preferably, the host computer of the heavy-duty scraper conveyor communicates with the industrial control computer of the heavy-duty scraper conveyor via Ethernet, using the TCP / IP protocol for bidirectional data transmission. The industrial control computer of the heavy-duty scraper conveyor is equipped with two PCI-1716 analog signal acquisition cards, one PCI-1784 digital signal acquisition card, one PCI-6208 driver card, a network card, and an xPC real-time kernel. The PCI-1716 analog signal acquisition card, PCI-1784 digital signal acquisition card, PCI-6208 driver card, network card, and xPC real-time kernel are connected to the PCI slots of the industrial control computer and are powered by the industrial control computer's power supply. The signal conditioning box contains four analog signal conditioning cards. The system includes a current-driven conditioning board and a sensor power supply module. The analog conditioning board converts the 4-20mA current signals from the laser displacement sensor, hydraulic sensor, displacement sensor, and tension / compression sensor of the heavy-duty scraper conveyor into a -10V-10V voltage signal that can be acquired by the PCI-1716 A / D board. The PCI-6208 driver board converts the digital signal calculated by the fuzzy self-tuning PID controller into a -10V-10V voltage signal, which is then converted into a -40mA-40mA current signal by the signal conditioning system to drive the servo valve. The signal is then output to the tensioning hydraulic cylinder of the heavy-duty scraper conveyor to adjust the chain tension and achieve vibration reduction.

[0072] In this embodiment, the host computer, fuzzy self-tuning PID controller, industrial computer, PCI-1716 analog acquisition board, PCI-1784 digital acquisition board, PCI-6208 driver board, network card, and xPC real-time kernel all adopt existing products or structures well known to those skilled in the art, and their interconnection, communication, or control methods also adopt existing communication or control methods well known to those skilled in the art.

[0073] By comparing the meshing force with the meshing force safety threshold, the tension and compression signals collected by the tension and compression sensors are transmitted to the PCI-1716 board via a conditioning module and converted into digital signals. The fuzzy self-tuning PID controller calculates the extension length l of the servo hydraulic cylinder piston rod according to presets known to those skilled in the art. In this embodiment, the presets refer to a series of reference values ​​and control parameters set before the system starts operating, based on the design parameters, operating conditions, and safety requirements of the heavy-duty scraper conveyor. These preset values ​​include: the meshing force safety threshold; control strategy parameters, including the parameters of the fuzzy self-tuning PID controller, namely proportional, integral, and derivative, used to adjust the action of the servo hydraulic cylinder; and the piston rod extension length E via the servo valve flow constant K. vpl The area A of the working end of the hydraulic cylinder pe To calculate the required change in pressure for elongation. The required change in pressure for elongation is ΔF = F. t -F safe F t For the meshing force, F safe The engagement force safety threshold is F when it is too tight. safe =F max When F is too loose safe =F min K vpl It is the servo valve flow constant, A pe It is the working end area of ​​the hydraulic cylinder. D is the effective piston diameter of the hydraulic cylinder. After simplification, we can obtain... This digital signal, i.e., the length signal, is converted into an analog signal by the PCI-6208 board. The conditioning module controls the action of the servo valve connected to the servo hydraulic cylinder. The aforementioned length signal is transmitted to the hydraulic cylinder position tracking controller. At the same time, it combines the displacement signal from the displacement sensor, the tension / compression signal from the tension / compression sensor, and the oil pressure signal from the oil pressure sensor of the servo-driven hydraulic cylinder of the heavy-duty scraper conveyor to control the servo valve control current of the servo hydraulic cylinder and transmit it to the servo valve. This controls the magnitude of the driving force of the servo-driven hydraulic cylinder to adjust the chain tension. The servo hydraulic cylinder is fixed on the tail of the telescopic machine.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications and equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A control method for a self-adjusting chain tension system of a heavy-duty scraper conveyor, characterized in that, The heavy-duty scraper conveyor chain tension self-adjusting system includes a sprocket with cavities evenly arranged radially. The cavities are filled with damping particles, and the damping particle filling rate in the cavities is 50-60%. The sprocket is equipped with a baffle for sealing the cavities. The damping particles, cavities, and baffles constitute a particle resistance device structure. Laser displacement sensors for detecting the vibration signals of the sprocket in the horizontal and vertical directions are installed on the tail of the heavy-duty scraper conveyor, which is aligned with the center point of the sprocket. The control method specifically includes: (1) The resistance generated by the particle resistance structure on the sprocket is divided into horizontal resistance and vertical resistance, denoted as F. x (δ) represents the horizontal contact force between the damping particles and the inner wall of the sprocket cavity, i.e., the horizontal resistance. y (δ) represents the contact force between the damping particles and the inner wall of the sprocket cavity in the vertical direction, i.e., the vertical resistance. The horizontal resistance F... x (δ) and vertical resistance F y Substituting (δ) into the vibration control equation of the chain drive system, the following equation is obtained to verify the rationality of the particle resistance device structural design: Where: c1 is the damping coefficient of the sprocket and bearing in the horizontal direction, c2 is the damping coefficient of the sprocket and bearing in the vertical direction, k1 is the stiffness coefficient of the sprocket and bearing in the horizontal direction, k2 is the stiffness coefficient of the sprocket and bearing in the vertical direction, is the vibration excitation of the sprocket in the horizontal direction, x, These represent the horizontal vibration displacement, vibration velocity, and vibration acceleration of the sprocket, respectively. These represent the vertical vibration displacement, vibration velocity, and vibration acceleration of the sprocket, respectively; m is the mass of the sprocket. (2) After verification, before the chain tension self-adjustment system of the heavy scraper conveyor is put into operation, the horizontal vibration threshold X and vertical vibration threshold Y of the sprocket are set according to the no-load and full-load conditions of the scraper conveyor. (3) Determine whether the horizontal and vertical vibration signals of the sprocket collected by the laser displacement sensor are within the set vibration safety threshold X and vertical vibration threshold Y ranges. The specific determination method is as follows: The collected vibration signal value is less than the set vibration threshold, indicating that the vibration is small. The industrial control computer of the heavy-duty scraper conveyor outputs an un-overlimit signal, and the chain tension self-adjustment control system is silent, that is, the chain tension is not adjusted. Specifically, it includes: using a laser displacement sensor to collect the vibration signals of the sprocket in the horizontal and vertical directions in real time, including vibration displacement, vibration velocity and vibration acceleration. The collected vibration signals are preprocessed, and the processed vibration signal values are compared with the preset horizontal vibration threshold X and vertical vibration threshold Y. If the collected vibration signal value is less than the set vibration threshold, it is considered that the vibration is within the safe range and the chain tension is not adjusted. The specific judgment formula is: V x < X and V y < Y, where: V x is the vibration signal value in the horizontal direction, V y is the vibration signal value in the vertical direction, X is the horizontal vibration threshold, and Y is the vertical vibration threshold; If the collected vibration signal exceeds the set vibration threshold, it indicates excessive vibration of the sprocket. The industrial control computer of the heavy-duty scraper conveyor will output a judgment signal indicating excessive sprocket vibration. The specific judgment formula is: V x >X or V y >Y, where: Vx is the vibration signal value in the horizontal direction, Vy is the vibration signal value in the vertical direction, X is the horizontal vibration threshold, and Y is the vertical vibration threshold; (4) The host computer of the heavy-duty scraper conveyor receives the sprocket vibration too large judgment signal sent by the industrial control computer of the heavy-duty scraper conveyor, and obtains the real-time chain tension information through the following formula: In the formula: F x F is the lateral meshing force of the chain link engagement section; y F is the longitudinal meshing force of the chain ring meshing part; t For meshing force; T O1 The chain tension of the flat ring; T O2 T is the chain tension of the flat ring II; O3 α is the chain tension of the third flat ring; α is the meshing angle of the second flat ring; θ is the meshing angle of the third flat ring; β is the meshing angle of the fourth flat ring. (5) Based on the magnitude of the meshing force, control the operation of the servo valve of the heavy-duty scraper conveyor to loosen or tighten the chain, thereby reducing the vibration of the sprocket; specifically including: preset the meshing force safety threshold F safe If F t <F safe The system will increase the pressure of the hydraulic cylinder through the servo valve to tension the chain; if F t >F safe The system will reduce the pressure in the hydraulic cylinder through a servo valve, causing the chain to loosen.

2. The control method for a heavy-duty scraper conveyor chain tension self-adjusting system according to claim 1, characterized in that, The sprocket has six cavities evenly arranged radially.

3. The control method for a heavy-duty scraper conveyor chain tension self-adjusting system according to claim 1, characterized in that, The damping particles are steel ball particles and rubber particles, with a ratio of 1:

1.

4. The control method for a heavy-duty scraper conveyor chain tension self-adjusting system as described in claim 1, characterized in that: The vibration signals include the vibration displacement, vibration velocity, and vibration acceleration of the sprocket.

5. The control method for a heavy-duty scraper conveyor chain tension self-adjusting system according to claim 1, characterized in that, The heavy-duty scraper conveyor is equipped with two laser displacement sensors at its tail, which are used to detect the vibration information of the sprocket in the horizontal and vertical directions, respectively.

6. The control method for a heavy-duty scraper conveyor chain tension self-adjusting system according to claim 1, characterized in that, The host computer of the heavy-duty scraper conveyor communicates with the industrial control computer of the heavy-duty scraper conveyor via Ethernet, using the TCP / IP protocol for bidirectional data transmission. The industrial control computer of the heavy-duty scraper conveyor is equipped with two PCI-1716 analog signal acquisition cards, one PCI-1784 digital signal acquisition card, one PCI-6208 driver card, a network card, and an xPC real-time kernel. The PCI-1716 analog signal acquisition card, PCI-1784 digital signal acquisition card, PCI-6208 driver card, network card, and xPC real-time kernel are connected to the PCI slots of the industrial control computer and are powered by the industrial control computer's power supply. The signal conditioning box contains four analog signal conditioning cards and one power supply. The system includes a flow-driven conditioning board and a sensor power supply module. The analog conditioning board converts the 4-20mA current signals from the laser displacement sensor, hydraulic sensor, displacement sensor, and tension / compression sensor of the heavy-duty scraper conveyor into a -10V-10V voltage signal that can be acquired by the PCI-1716 A / D board. The PCI-6208 driver board converts the digital signal calculated by the fuzzy self-tuning PID controller into a -10V-10V voltage signal, which is then converted into a -40mA-40mA current signal by the signal conditioning system to drive the servo valve. The signal is then output to the servo hydraulic cylinder of the heavy-duty scraper conveyor to adjust the chain tension and achieve vibration reduction.

7. The control method for a heavy-duty scraper conveyor chain tension self-adjusting system according to claim 6, characterized in that, The calculation formula for the fuzzy self-tuning PID controller is as follows: ΔF=F t -F safe ; In the formula: Ft is the meshing force; F safe K represents the safe threshold for meshing force. P '、K I 'and K D 'They are K' P ,K I ,K D Initial parameters; G P G I G D ΔK is the correction value, and ΔK is a constant. P ΔK I ΔK D They are K P K I K D The value obtained through fuzzy reasoning; △F is the changing pressure value required for elongation; K P ,K I ,K D These are the proportional, integral, and derivative gains, respectively, and U is the controller output.

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