Heavy scraper conveyor chain tension self-adjusting system and control method

Abstract

The invention relates to a heavy scraper conveyor chain tension self-adjusting system and a control method, the system comprises a chain wheel, the chain wheel is uniformly provided with a cavity along the radial direction, the cavity is filled with damping particles, the filling rate of the damping particles in the cavity is 50-60%, the chain wheel is provided with a baffle plate for sealing the cavity, and the baffle plate is provided with a baffle plate for sealing the cavity. The damping particles, the cavity and the baffle form a particle damper structure, laser displacement sensors used for detecting vibration signals of the chain wheel in the horizontal direction and the vertical direction are installed on the telescopic tail of the heavy scraper conveyor in the horizontal direction and the vertical direction and aligned with the center point of the chain wheel, and an active and passive mixed damping mode is formed. Vibration of the chain wheel can be efficiently restrained, and the chain tension is adjusted to be within a safety threshold value.

Description

Technical Field

[0001] The invention relates to the field of mining scraper conveyors, and in particular to a heavy-duty scraper conveyor chain tension self-adjusting system and a control method. Background Art

[0002] The scraper conveyor for mining is one of the key equipments in the comprehensive mechanized coal mining face. Whether it can operate reliably, stably and efficiently directly affects the safety and production capacity of modern coal mines. The working environment of the scraper conveyor for mining is harsh, with many uncertain factors, obvious random vibration and impact. Among them, the scraper chain is the component that directly bears the load of falling coal. When it bears the impact of falling coal, the chain will be compressed and tightened, resulting in greater chain tension, which will cause the tail sprocket to vibrate strongly, so that the scraper chain will be loosened or even piled up at the separation point of the driving sprocket, resulting in chain drop, chain jam and chain breakage. How to suppress the vibration of the sprocket has become the current research focus. Since the particle damping vibration reduction technology was proposed, it has been widely used in aviation, aerospace, machinery, civil engineering and other fields. It can still work well in harsh environments, is almost not limited by temperature, and has no problems such as material degradation and fatigue effect. In addition, its vibration reduction frequency is wide, the cost is low, and the recovery ability is strong. The particle damper mainly relies on the contact collision and energy dissipation between the damping particles and the damper to reduce vibration, and the vibration reduction effect is obvious. At present, the method of reducing sprocket vibration in practical application is mainly to adjust the chain tension by telescopic tail, but most of them are methods of directly measuring chain tension by tension sensor. In harsh working environment, the tension sensor is subject to many interference factors, which easily leads to large errors and low reliability, thus reducing the adjustment effect. Therefore, how to reduce the vibration of sprocket by particle damping technology and how to use reliable information to control the chain tension adjustment system to optimize the design of the vibration reduction device of scraper conveyor are urgently needed. Summary of the invention

[0003] The invention provides a heavy-duty scraper conveyor chain tension self-adjusting system and a control method.

[0004] A heavy-duty scraper conveyor chain tension self-adjusting system comprises a sprocket, wherein the sprocket has cavities evenly arranged in the radial direction, the cavities are filled with damping particles, the filling rate of the damping particles in the cavities is 50-60%, the sprocket is equipped with a baffle for sealing the cavity, the damping particles, the cavity and the baffle constitute a particle resistance structure, and a laser displacement sensor for detecting the vibration signal of the sprocket in the horizontal and vertical directions is installed on the tail of the heavy-duty scraper conveyor aligned with the center point of the sprocket in the horizontal and vertical directions.

[0005] Preferably, the sprocket has 6 cavities evenly arranged in the radial direction.

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

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

[0008] Preferably, two laser displacement sensors are installed on the tail of the heavy-duty scraper conveyor, which are used to detect the vibration information of the sprocket in the horizontal direction and the vertical direction respectively.

[0009] The present invention also provides a control method for the above system, which specifically includes:

[0010] (1) The resistance generated by the particle drag structure on the sprocket is divided into horizontal resistance and vertical resistance, expressed as F x (δ) is the contact force between the damping particles and the inner wall of the sprocket cavity in the horizontal direction, i.e., the horizontal resistance, F y (δ) is 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 drag structure design:

[0011]

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

[0013] (2) After the verification is completed, before the chain tension self-adjusting system of the heavy-duty scraper conveyor works, the horizontal vibration threshold value X and the vertical vibration threshold value Y of the sprocket are set according to the conditions of no load and full load 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. 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 remains silent, that is, no chain tension adjustment is performed. Specifically, it includes: using a laser displacement sensor to collect the vibration signals of the sprocket 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 no chain tension adjustment is performed. 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 is too large. The industrial control computer of the heavy-duty scraper conveyor will output a determination signal that the vibration of the scraper conveyor sprocket 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 determination signal that the vibration of the sprocket of the heavy-duty scraper conveyor 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 flat link one; T O2 is the chain tension of flat link two; T O3 is the chain tension of flat link three; α is the meshing angle of flat link two; θ is the meshing angle of flat link three; β is the meshing angle of flat link four;

[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; specifically, it includes: presetting the meshing resultant 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 tighten the chain; if F t >F safe , the system will reduce the pressure of the hydraulic cylinder through the servo valve to relax the chain.

[0021] Preferably, the host computer of the heavy-duty scraper conveyor communicates with the industrial computer of the heavy-duty scraper conveyor through Ethernet, and uses the TCP / IP protocol for two-way data transmission; the industrial computer of the heavy-duty scraper conveyor is installed with 2 PCI-1716 analog quantity acquisition boards, 1 PCI-1784 digital quantity acquisition board, 1 PCI-6208 driver board, network card and xPC real-time kernel, the PCI-1716 analog quantity acquisition board, PCI-1784 digital quantity acquisition board, PCI-6208 driver board, network card and xPC real-time kernel are connected to the PCI slot of the industrial computer and are powered by the power supply of the industrial computer, and 4 analog quantity conditioning boards are installed in the signal conditioning box, 1 The analog conditioning board converts the 4--20mA current signal output by the laser displacement sensor, oil pressure sensor, displacement sensor and tension pressure sensor of the heavy-duty scraper conveyor into a -10V--10V voltage signal that can be collected by the A / D board PCI-1716; the PCI-6208 driver board converts the digital signal calculated by the fuzzy self-tuning PID controller into a -10V--10V voltage signal, and converts it into a -40mA--40mA current signal to drive the servo valve through the signal conditioning system, and then controls the output to the tensioning hydraulic cylinder of the heavy-duty scraper conveyor to adjust the chain tension to achieve vibration reduction effect.

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

[0023]

[0024] ΔF=F t -F safe ;

[0025] Where: Ft is meshing force; F safe K is the meshing force safety threshold; P ', K I ' and K D 'K P ,K I ,K D The initial parameters of G P , G I , G D is the correction amount, is a constant; ΔK P , ΔK I , ΔK D They are K P, K I , K D The value after fuzzy reasoning; the change in pressure required for △F elongation; K P ,K I ,K D are the gains of the proportional, integral and differential terms respectively, and U is the output of the controller.

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

[0027] 1. The present invention opens a cavity in the sprocket and places particle damping. The damping particles absorb the energy of the sprocket vibration, which can reduce the vibration of the sprocket of the scraper conveyor during operation in a passive vibration reduction manner and increase the stability of the sprocket.

[0028] 2. The present invention proposes to obtain the vibration information of the sprocket through a laser displacement sensor to determine whether it is necessary to adjust the chain tension, and to determine the tightness of the chain through the size of the sprocket chain ring meshing force, which can improve the accuracy and stability of chain tension control.

[0029] 3. The present invention uses a telescopic tail to change the center distance between the nose and tail of the machine to adjust the chain tension through a chain tension self-control system, forming an active and passive hybrid shock absorption mode, which can effectively suppress the vibration of the sprocket caused by abnormal chain tension and adjust the chain tension to be within a safe threshold. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0032] Figure 3 It is the hardware flow chart of the chain tension automatic control system of the present invention.

[0033] Figure 4 It is a control strategy flow chart of the chain tension self-control system of the present invention.

[0034] Figure 5 This is the meshing vibration analysis diagram of the chain transmission system of the present invention

[0035] Figure 6 The sprocket chain meshing process diagram of the present invention

[0036] In the figure: 1-sprocket, 1-1, steel ball particles, 1-2, rubber particles, 1-3, baffle, 1-4, screw hole, 1-5, deep groove ball bearing, 2, laser displacement sensor 1, 3, laser displacement sensor 2, 4, telescopic machine tail, 5, tension pressure sensor, 6, servo valve, 7, displacement sensor, 8, oil pressure sensor, 9, servo hydraulic cylinder, 10, coal mining machine, 11, random coal falling, 12, host computer, 13, industrial computer, 14, signal conditioning box, 15, reaction seat. Specific implementation methods

[0037] In order to make the purpose, technical solution and optimization points of this embodiment clearer and more specific, 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, this embodiment provides a heavy-duty scraper conveyor chain tension self-adjusting system and control method.

[0039] A heavy-duty scraper conveyor chain tension self-adjusting system comprises a sprocket, wherein the sprocket has cavities evenly arranged in the radial direction, the cavities are filled with damping particles, the filling rate of the damping particles in the cavities is 50-60%, the sprocket is equipped with a baffle for sealing the cavity, the damping particles, the cavity and the baffle constitute a particle resistance structure, and a laser displacement sensor for detecting the vibration signal of the sprocket in the horizontal and vertical directions is installed on the tail of the heavy-duty scraper conveyor aligned with the center point of the sprocket in the horizontal and vertical directions.

[0040] Preferably, the sprocket has 6 cavities evenly arranged in the radial direction.

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

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

[0043] Preferably, two laser displacement sensors are installed on the tail of the heavy-duty scraper conveyor, which are used to detect the vibration information of the sprocket in the horizontal direction and the vertical direction respectively.

[0044] The present invention also provides a control method for the above system, which specifically includes:

[0045] (1) The resistance generated by the particle drag structure on the sprocket is divided into horizontal resistance and vertical resistance, expressed as F x (δ) is the contact force between the damping particles and the inner wall of the sprocket cavity in the horizontal direction, i.e., the horizontal resistance, F y (δ) is 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 drag structure design:

[0046]

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

[0048] (2) After the verification is completed, before the chain tension self-adjusting system of the heavy-duty scraper conveyor works, the horizontal vibration threshold value X and the vertical vibration threshold value Y of the sprocket are set according to the no-load and full-load conditions of the scraper conveyor; before setting the threshold value, the vibration data of the sprocket of the heavy-duty scraper conveyor under no-load and full-load conditions are collected; two laser displacement sensors (laser displacement sensor 12 and laser displacement sensor 23) installed on the sprocket are used to collect data including parameters such as vibration displacement, vibration velocity and vibration acceleration, and the collected data are statistically analyzed to determine the distribution characteristics of the sprocket vibration under no-load and full-load conditions, including the mean value, standard deviation, maximum value and minimum value; the threshold values ​​X and Y are set based on the data analysis results, taking into account the balance between safety and efficiency; the threshold value is set to more than 95% of the vibration data under full load to ensure that the sprocket is in most cases The vibration will not exceed this value. When setting the threshold value in practice, a safety factor of 1.1-1.3 is introduced. The actual threshold value is 10% to 30% higher than the value obtained by data analysis to provide a certain safety margin. The safety factor of this embodiment is 1.2. In this embodiment, the average value of the vertical vibration acceleration of the sprocket is 0.5g, the standard deviation is 0.2g, and the maximum value is 1.2g under full load; the average value of the horizontal vibration acceleration is 0.5g, the standard deviation is 0.2g, and the maximum value is 1.0g. The threshold is set; vertical vibration threshold Y: take the maximum value 1.2g multiplied by the safety factor 1.2, and the vertical vibration threshold Y=1.2g*1.2=1.44g, horizontal vibration threshold X: the maximum value of the horizontal vibration is 1.0g, multiplied by the safety factor 1.2, and 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. 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 un-overlimit 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 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 is too large. The industrial control computer of the heavy-duty scraper conveyor will output a signal for determining that the vibration of the scraper conveyor sprocket 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 signal for determining that the vibration of the scraper conveyor sprocket is too large sent by the industrial control computer of the heavy-duty scraper conveyor; during the meshing transmission of the sprocket 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 and the chain, it is necessary to analyze the meshing force of the sprocket and the chain; the analysis of the meshing and disengaging points of the chain and the tail sprocket is as shown in the appendix Figure 5 as shown;

[0053] During the meshing transmission of the sprocket 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 rotating clockwise as an example, during the movement process, mainly three flat rings are in contact with the sprocket, and the chain tension of the flat ring is approximately equal to the meshing force generated by the contact with the sprocket. To analyze the meshing vibration of the sprocket and the chain, it is necessary to analyze the meshing force of the sprocket and the chain; the analysis of the meshing and disengaging points of the chain and the tail sprocket is as shown in the appendix Figure 5 as shown;

[0054] Considering the meshing process of the chain drive, the scraper chain is surrounded by the sprocket in a polygonal shape; when the tail drive runs at a constant angular velocity, the speed and load of the scraper chain will fluctuate due to the polygonal effect; in order to describe this fluctuation, based on the NMC model (the NMC model refers to the Neural Marching Cubes model well known to those skilled in the art. Through the upgrade of deep learning, a neural network is used to predict the boundary of each cube, and a continuous surface is generated using an efficient octree structure. This is a 3D reconstruction technology based on deep learning), the height distance between the meshing point and the meshing point of the sprocket chain is expressed as follows:

[0055]

[0056] Where: R0 is the pitch radius of the tail sprocket, α0 and β are the meshing angles of the sprocket ring at the meshing point and the meshing point; h O1 and h OC h are the vertical distances from the meshing point and the sprocket geometric center to the bottom plate of the middle groove respectively; B and h OD They are respectively the vertical distances from the meshing point and the geometric center of the sprocket to the middle plate of the middle groove; the middle groove in this embodiment is the vertical groove of the sprocket.

[0057] The unloaded side chain is in a suspended state supported by the middle trough bottom plate. Figure 5 The information can be used to obtain the drape tension at point C:

[0058] T C =8λgh 3 O1 / 9(S2-L) 2

[0059] Where: λ is the mass per unit length of the chain; g is the acceleration of gravity; S2 is the length of the chain on the unloaded side; 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 relies on the meshing force to drive the chain ring to move, thus realizing the meshing process of the chain transmission system. According to the meshing contact of the sprocket and chain, the meshing process is divided into three stages: meshing in, meshing, and meshing out. This embodiment takes a five-tooth sprocket rotating clockwise as an example. The meshing process is shown in the figure below. Figure 6As shown; in the meshing stage, when the arc segment O1 of the flat ring 2 first contacts the sprocket tooth surface, the corresponding meshing angle is α0, the sprocket continues to rotate, and the vertical ring and the sprocket enter the meshing stage. When the arc segment O1 of the flat ring 2 coincides with the center of the chain socket, the flat ring 2 completes the meshing process with the sprocket; as the vertical ring enters the vertical groove of the sprocket, and the arc segment of the flat ring zero is aligned with the meshing center of the chain socket on the back of the sprocket tooth, the vertical ring is meshed with the sprocket; then, the sprocket continues to rotate clockwise, and the flat ring zero is pulled toward the chain by the traction force of the vertical ring. When the arc segment O0 of 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 meshing angle variation domain of 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, and the meshing angle of flat ring four is approximately the meshing angle β of the meshing point; the meshing angle of the corresponding meshing point in the above meshing process is obtained as:

[0061]

[0062] Where: S1 is the length of the chain on the loaded side; α is the meshing angle of the second flat ring; θ is the meshing angle of the third flat ring; w S is the angular velocity of the sprocket rotation; T is the meshing period; L has the same definition, n represents a natural number, and t is the sprocket rotation time.

[0063] When the sprocket rotates, T B is the chain tension when the chain separates from the sprocket at the tail, which is approximately the pre-tension of the chain; T O1 is the chain tension at the tail of the machine when the chain and sprocket just meet; T1 is the chain tension at the head of the machine when the chain and sprocket separate; T2 is the chain tension at the head of the machine when the chain and sprocket just meet. Ignoring the influence of factors such as the time-varying meshing friction between the sprocket and the chain link, the centrifugal force of rotation, and the principle of the tension point-by-point calculation method, the stress between each link has a linear relationship, and the following expression can be obtained to calculate T O1 :

[0064]

[0065] Where: W U W is the running resistance of the loaded side of the middle tank; D k is the running resistance of the unloaded side of the middle tank; f k is the resistance coefficient of the material moving in the chute; u k is the moving resistance coefficient of the loaded side chain and the middle groove, and k is u =0.3; k d k is the moving resistance coefficient of the unloaded side chain and the middle groove, and k is d=0.5; q is the resistance coefficient of the coal falling in the chute; λ is the unit length mass of the chain; L is the center distance from the head sprocket to the tail sprocket; g is the acceleration of gravity. Similarly, T O2 and T O3 The calculation principle and T O1 Same; According to the data obtained by the above formula, the lateral meshing force F of the meshing transmission system is calculated in combination with the meshing angle change of each meshing point during the rotation of the sprocket. x , longitudinal meshing force F y , meshing force F t , with meshing force F t and meshing force safety threshold F safe To compare and judge the tightness of the chain, the calculation formula is as follows:

[0066] The real-time chain tension information is obtained through the following formula:

[0067]

[0068] Where: F x F is the lateral meshing force of the wheel chain ring meshing part; y F is the longitudinal meshing force of the wheel chain ring meshing part; t is the meshing force; T O1 is the chain tension of flat ring 1; T O2 is the chain tension of flat ring 2; T O3 is the chain tension of flat ring three; α is the meshing angle of flat ring two; θ is the meshing angle of flat ring three; β is the meshing angle of flat ring four;

[0069] According to the size of the meshing force, the servo valve of the heavy-duty scraper conveyor is controlled to loosen or tighten the chain, thereby reducing the vibration of the sprocket; specifically, it includes: presetting 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 tighten the chain; if F t >F safe , the system will reduce the pressure of the hydraulic cylinder through the servo valve to relax the chain.

[0070] In this embodiment, the meshing force safety threshold F is preset. safe When the meshing force changes under different conditions, the data are collected to adjust and verify the safety threshold; the specific meshing force safety threshold F safe The determination includes the following parameters: minimum safe meshing force F min , Maximum safe meshing force F max , the operating meshing force is the currently measured meshing force F op, safety factor S, safety factor S is greater than 1; meshing force safety threshold F safe The range of F can be determined by the following formula: min =F op *SF max =F op *S; where F op It is the operating meshing force that can be obtained by experiments or calculations by technicians in this field under specific load and speed conditions, and S is the safety factor that can be determined by technicians in this field based on experience and safety requirements.

[0071] Preferably, the host computer of the heavy-duty scraper conveyor communicates with the industrial computer of the heavy-duty scraper conveyor through Ethernet, and uses the TCP / IP protocol for two-way data transmission; the industrial computer of the heavy-duty scraper conveyor is installed with 2 PCI-1716 analog quantity acquisition boards, 1 PCI-1784 digital quantity acquisition board, 1 PCI-6208 driver board, network card and xPC real-time kernel, the PCI-1716 analog quantity acquisition board, PCI-1784 digital quantity acquisition board, PCI-6208 driver board, network card and xPC real-time kernel are connected to the PCI slot of the industrial computer and are powered by the power supply of the industrial computer, and 4 analog quantity conditioning boards are installed in the signal conditioning box, 1 The analog conditioning board converts the 4--20mA current signal output by the laser displacement sensor, oil pressure sensor, displacement sensor and tension pressure sensor of the heavy-duty scraper conveyor into a -10V--10V voltage signal that can be collected by the A / D board PCI-1716; the PCI-6208 driver board converts the digital signal calculated by the fuzzy self-tuning PID controller into a -10V--10V voltage signal, and converts it into a -40mA--40mA current signal to drive the servo valve through the signal conditioning system, and then controls the output to the tensioning hydraulic cylinder of the heavy-duty scraper conveyor to adjust the chain tension to achieve vibration reduction effect.

[0072] 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 of this embodiment all adopt existing products or structures well known to those skilled in the art, and their mutual connection methods, communication or control methods also adopt existing communication methods 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 pressure signal collected by the tension and pressure sensor is transmitted to the PCI-1716 board through the conditioning module and converted into a digital signal. The fuzzy self-tuning PID controller calculates the rod length l of the servo hydraulic cylinder piston rod according to the preset known to those skilled in the art; the preset of this embodiment refers to a series of reference values ​​and control parameters set before the system starts running, based on the design parameters, operating conditions and safety requirements of the heavy-duty scraper conveyor; these preset values ​​include: meshing force safety threshold, control strategy parameters: including the parameters of the fuzzy self-tuning PID controller, namely, proportion, integration, and differentiation, which are used to adjust the action of the servo hydraulic cylinder; the rod length E of the piston rod is calculated by the servo valve flow constant K vpl and the area A of the working end of the hydraulic cylinder pe To calculate the change in pressure required for elongation The change in pressure required for elongation ΔF = F t -F safe , F t is the meshing force, F safe is the safety threshold of meshing force. When it is too tight, F safe =F max , when too loose F safe =F min， K vpl is the servo valve flow constant, A pe is the working end area of ​​the hydraulic cylinder, D is the effective piston diameter of the hydraulic cylinder, and after simplification, we can get This digital signal, namely the length signal, is converted into an analog quantity by the PCI-6208 board, and is controlled by the conditioning module to operate the servo valve connected to the servo hydraulic cylinder. The length signal is transmitted to the hydraulic cylinder position tracking controller. At the same time, the displacement signal of the displacement sensor of the servo drive hydraulic cylinder of the heavy scraper conveyor, the tension signal of the tension sensor and the oil pressure signal of the oil pressure sensor are combined to control the servo valve control current of the servo hydraulic cylinder and transmit it to the servo valve to control the driving force of the servo drive hydraulic cylinder to adjust the chain tension. The servo hydraulic cylinder is fixed on the tail of the telescopic machine.

[0074] The above contents are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. 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. Heavy-duty scraper conveyor chain tension self-adjusting system, characterized by: The invention comprises a sprocket, wherein cavities are evenly arranged in the radial direction, wherein the cavities are filled with damping particles, wherein the filling rate of the damping particles in the cavities is 50-60%, wherein the sprocket is provided with a baffle plate for sealing the cavity, wherein the damping particles, the cavity and the baffle plate constitute a particle resistance device structure, and a laser displacement sensor for detecting the vibration signal of the sprocket in the horizontal and vertical directions is installed on the tail of a heavy-duty scraper conveyor aligned with the center point of the sprocket in the horizontal and vertical directions.

2. The heavy-duty scraper conveyor chain tension self-adjusting system according to claim 1 is characterized in that: The sprocket is evenly arranged with 6 cavities along the radial direction.

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

1.

4. The heavy-duty scraper conveyor chain tension self-adjusting system according to claim 1, characterized in that: The vibration signal includes the vibration displacement, vibration velocity and vibration acceleration of the sprocket.

5. The heavy-duty scraper conveyor chain tension self-adjusting system according to claim 1, characterized in that: Two laser displacement sensors are installed on the tail of the heavy-duty scraper conveyor to detect the vibration information of the sprocket in the horizontal direction and the vertical direction respectively.

6. The control method of the chain tension self-adjusting system of a heavy-duty scraper conveyor according to claim 1 is characterized in that: Specifically include: (1) The resistance generated by the particle drag structure on the sprocket is divided into horizontal resistance and vertical resistance, expressed as F x (δ) is the contact force between the damping particles and the inner wall of the sprocket cavity in the horizontal direction, i.e., the horizontal resistance, F y (δ) is 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 drag structure design: Where: c1 is the damping coefficient of the sprocket and the bearing in the horizontal direction, c2 is the damping coefficient of the sprocket and the bearing in the vertical direction, k1 is the stiffness coefficient of the sprocket and the bearing in the horizontal direction, k2 is the stiffness coefficient of the sprocket and the bearing in the vertical direction, is the vibration excitation of the sprocket in the horizontal direction, x, Respectively represent the vibration displacement, vibration velocity, and vibration acceleration of the sprocket in the horizontal direction, y, They represent the vibration displacement, vibration velocity and vibration acceleration of the sprocket in the vertical direction respectively; m is the mass of the sprocket; (2) After the verification is completed, before the chain tension self-adjusting system of the heavy-duty scraper conveyor works, the horizontal vibration threshold value X and the vertical vibration threshold value Y of the sprocket are set according to the conditions of no load and full load 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. The specific determination method is as follows: (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 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 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; (32) The collected vibration signal is greater than the set vibration threshold, which means that the vibration of the sprocket is too large. The industrial computer of the heavy-duty scraper conveyor will output a judgment signal that the sprocket vibration 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; (4) The host computer of the heavy-duty scraper conveyor receives the sprocket vibration excessive judgment signal sent by the industrial computer of the heavy-duty scraper conveyor, and obtains the real-time chain tension information through the following formula: Where: F x F is the lateral meshing force of the wheel chain ring meshing part; y F is the longitudinal meshing force of the wheel chain ring meshing part; t is the meshing force; T O1 is the chain tension of flat ring 1; T O2 is the chain tension of flat ring 2; T O3 is the chain tension of flat ring three; α is the meshing angle of flat ring two; θ is the meshing angle of flat ring three; β is the meshing angle of flat ring four; (5) According to the size of the meshing force, the servo valve of the heavy-duty scraper conveyor is controlled to loosen or tighten the chain, thereby reducing the vibration of the sprocket; specifically, the meshing force safety threshold F is preset safe , if F t <F safe , the system will increase the pressure of the hydraulic cylinder through the servo valve to tighten the chain; if F t >F safe , the system will reduce the pressure of the hydraulic cylinder through the servo valve to relax the chain.

7. The control method of the chain tension self-adjusting system of a heavy-duty scraper conveyor according to claim 6 is characterized in that: The host computer of the heavy-duty scraper conveyor communicates with the industrial computer of the heavy-duty scraper conveyor through Ethernet, and uses the TCP / IP protocol for two-way data transmission; the industrial computer of the heavy-duty scraper conveyor is equipped with 2 PCI-1716 analog quantity acquisition boards, 1 PCI-1784 digital quantity acquisition board, 1 PCI-6208 driver board, network card and xPC real-time kernel, the PCI-1716 analog quantity acquisition board, PCI-1784 digital quantity acquisition board, PCI-6208 driver board, network card and xPC real-time kernel are connected to the PCI slot of the industrial computer and are powered by the power supply of the industrial computer, and the signal conditioning box is equipped with 4 analog quantity conditioning boards, 1 power The analog conditioning board converts the 4--20mA current signal output by the laser displacement sensor, oil pressure sensor, displacement sensor and tension pressure sensor of the heavy-duty scraper conveyor into a -10V--10V voltage signal that can be collected by the A / D board PCI-1716; the PCI-6208 driver board converts the digital signal calculated by the fuzzy self-tuning PID controller into a -10V--10V voltage signal, and converts it into a -40mA--40mA current signal to drive the servo valve through the signal conditioning system, and then controls the output to the servo hydraulic cylinder of the heavy-duty scraper conveyor to adjust the chain tension to achieve vibration reduction effect.

8. The control method of the chain tension self-adjusting system of a heavy-duty scraper conveyor according to claim 7 is characterized in that: The calculation formula of the fuzzy self-tuning PID controller is: ΔF=F t -F safe ; Where: Ft is meshing force; F safe K is the meshing force safety threshold; P ', K I ' and K D 'K P ,K I ,K D The initial parameters of G P , G I , G D is the correction amount, is a constant; ΔK P , ΔK I , ΔK D They are K P , K I , K D The value after fuzzy reasoning; △F is the change in pressure required for elongation; K P ,K I ,K D are the gains of the proportional, integral and differential terms respectively, and U is the output of the controller.

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