Method and device for monitoring chain elongation of scraper conveyor

Abstract

The invention relates to the technical field of scraper conveyors, in particular to a monitoring method and device for the chain elongation of a scraper conveyor, and the device comprises a permanent magnet, a Hall sensor, an encoder, an acceleration sensor and a control device. Permanent magnets are fixed to axes at the two ends of the scraper, Hall sensors are fixed to the ledge of the shovel plate side and the ledge of the baffle side of the middle trough body, and the Hall sensors are used for collecting magnetic field intensity signals of the scraper passing through the Hall sensors when the chain runs. The encoder and the acceleration sensor are arranged on the motor, the encoder is used for collecting the rotating speed of the motor, and the acceleration sensor is used for collecting the acceleration of the motor; the control device is connected with the Hall sensor, the encoder and the acceleration sensor and used for calculating the chain elongation of the scraper conveyor according to the magnetic field intensity signal, the acceleration and the rotating speed. Therefore, the detection efficiency of the chain elongation of the scraper conveyor and the accuracy and reliability of the detection result are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of scraper conveyors, and in particular to a method and device for monitoring the chain elongation of a scraper conveyor. Background Art

[0002] In the production process of fully mechanized coal mining faces, scraper conveyors serve as the core coal transportation equipment. Their operational stability and reliability directly impact coal mining efficiency and safe production. The chain, a key component for transmitting traction in scraper conveyors, faces several challenges during continuous operation. On the one hand, due to the dynamic changes in coal transport volume, the load borne by the chain is extremely uneven. When external pressure exceeds its elastic limit, plastic deformation occurs, causing the chain to permanently elongate. On the other hand, long-term friction and wear between the chain links causes the chain pitch to continuously increase, further exacerbating the chain elongation problem. Chain elongation disrupts the normal meshing relationship between the chain and the sprocket shaft assembly, easily leading to serious faults such as chain breakage and chain jamming. This not only significantly reduces coal mining efficiency, but can also damage equipment and even threaten the lives of underground workers.

[0003] In some scenarios, chain elongation measurement for scraper conveyors still relies primarily on traditional manual judgment, relying on experienced workers to assess chain condition through visual and auditory inspection. However, this method has drawbacks: the continuous transport of coal by scraper conveyors creates a buildup of coal, requiring tedious cleaning before workers can inspect the chain. Furthermore, the underground working environment is extremely noisy, making audible judgments about chain condition unreliable. Furthermore, manual inspections lack quantitative standards, hindering the accuracy and real-time nature of chain monitoring. Other inspection technologies also have limitations. Manual caliper measurement requires downtime, severely impacting production continuity, and measurement results are susceptible to subjective interference. Machine vision inspections often suffer from image recognition failures due to the pervasive dust and complex, variable lighting conditions underground. Therefore, the efficiency, accuracy, and reliability of scraper conveyor chain elongation measurements using these methods are low. Summary of the Invention

[0004] In order to solve the technical problem of low detection efficiency, accuracy and reliability of the chain elongation of a scraper conveyor, the present invention aims to provide a method and device for monitoring the chain elongation of a scraper conveyor. The technical solution adopted is as follows:

[0005] In the first aspect, an embodiment of the present invention discloses a device for monitoring the chain elongation of a scraper conveyor, wherein the scraper conveyor includes a middle trough body, a motor, a scraper and a chain, the middle trough body includes a shovel side and a baffle side, and the device for monitoring the chain elongation of the scraper conveyor includes: a permanent magnet, a Hall sensor, an encoder, an acceleration sensor and a control device; permanent magnets are fixed on the axes at both ends of the scraper, and the permanent magnets are used to generate a magnetic field at the scraper, and the trough sides on the shovel side and the baffle side of the middle trough body are fixed with Hall sensors, and the Hall sensor is used to collect the magnetic field strength signal of the scraper passing through the Hall sensor when the chain is running; the encoder and the acceleration sensor are both arranged on the motor, the encoder is used to collect the motor speed, and the acceleration sensor is used to collect the motor acceleration; the control device is respectively connected to the Hall sensor, the encoder and the acceleration sensor, and is used to calculate the chain elongation of the scraper conveyor based on the magnetic field strength signal, acceleration and speed.

[0006] Optionally, the monitoring device for the chain elongation of the scraper conveyor also includes: an automatic chain tensioning valve group, which is respectively connected to the tail of the scraper conveyor and the control device; when the chain elongation exceeds a first threshold value, the control device controls the extension cylinder of the automatic chain tensioning valve group to drive the tail of the scraper conveyor to extend through the piston rod of the automatic chain tensioning valve group to tension the chain, and the length of the extension of the tail of the scraper conveyor is half of the chain elongation.

[0007] Optionally, grooves are provided on the axe surfaces at both ends of the scraper, and screw holes are provided in the grooves; fastening bolts pass through the permanent magnets and the screw holes to fix the permanent magnets in the grooves.

[0008] Optionally, the permanent magnet has two magnetic poles, an N pole and an S pole, and the polarities of the magnetic poles on two opposite sides of the permanent magnets on adjacent scrapers are opposite.

[0009] In a second aspect, an embodiment of the present invention discloses a method for monitoring the chain elongation of a scraper conveyor, comprising: when the chain of the scraper conveyor is running, obtaining the magnetic induction intensity signal of the scraper passing through the Hall sensor, the speed and acceleration of the motor of the scraper conveyor; predicting the predicted chain length at the current sampling moment based on the first theoretical chain length of the chain passing through the Hall sensor at the previous sampling moment of the scraper conveyor, the speed and acceleration of the motor; determining the observed chain length at the current sampling moment based on the second theoretical chain length of the chain passing through the Hall sensor at the current sampling moment, the speed and acceleration of the motor, wherein the theoretical chain length is determined at the moment corresponding to the magnetic induction intensity signal generated by the Hall sensor triggered by the permanent magnet of the scraper passing through the Hall sensor; determining the actual chain length of the scraper conveyor based on the predicted chain length and the observed chain length of the scraper conveyor, and determining the difference between the actual chain length and the initial chain length of the scraper conveyor as the chain elongation of the scraper conveyor.

[0010] Optionally, when the chain of the scraper conveyor is running, after obtaining the magnetic induction intensity signal of the scraper passing through the Hall sensor, the speed and acceleration of the motor of the scraper conveyor, the method also includes: when the speed of the motor is a constant, using the speed, the speed ratio of the reducer of the scraper conveyor, the number of sprocket teeth of the scraper conveyor and the chain pitch, calculating the chain speed of the scraper conveyor; calculating the first moment and the second moment when the permanent magnet of each adjacent scraper triggers the magnetic induction intensity signal generated by the Hall sensor; determining the theoretical length of the chain when the scraper conveyor moves at a uniform speed based on each first moment, the second moment and the chain speed; when the speed of the motor changes at a uniform speed, obtaining the initial chain speed of the chain when the speed of the motor begins to change; determining the theoretical length of the chain when the scraper conveyor moves at a uniform speed based on each first moment, the second moment, the acceleration of the motor of the scraper conveyor between the first moment and the second moment and the initial chain speed; determining the chain elongation of the scraper conveyor according to the theoretical length of the chain, the initial length of the distance between the center points of adjacent chain links corresponding to adjacent scrapers and the number of scrapers passing the Hall sensor.

[0011] Optionally, the chain speed of the scraper conveyor is calculated using the following formula:

[0012]

[0013] Among them, v represents the chain speed of the scraper conveyor, n represents the speed of the motor of the scraper conveyor, i represents the speed ratio of the reducer of the scraper conveyor, Z represents the number of sprocket teeth of the scraper conveyor, and P represents the chain pitch.

[0014] Optionally, the chain elongation of the scraper conveyor is calculated using the following formula:

[0015]

[0016] Among them, δ represents the chain elongation of the scraper conveyor, L t represents the theoretical length of the chain, N represents the number of scrapers passing through the Hall sensor, and L0 represents the initial length of the distance between the center points of adjacent chain links corresponding to adjacent scrapers.

[0017] Optionally, predicting the predicted chain length at the current sampling moment based on the first chain theoretical length of the chain passing through the Hall sensor at the previous sampling moment of the scraper conveyor, the speed of the motor and the acceleration includes: determining the chain speed of the scraper conveyor at the previous sampling moment based on the speed of the motor; substituting the chain speed, the first chain theoretical length, the acceleration and the interval between adjacent sampling moments of the scraper conveyor at the previous sampling moment into the state equation; using the state equation to predict the predicted chain length at the current sampling moment; determining the observed chain length at the current sampling moment based on the second chain theoretical length of the chain passing through the Hall sensor at the current sampling moment, the speed of the motor and the acceleration includes: determining the chain speed of the scraper conveyor at the current sampling moment based on the speed of the motor; substituting the chain speed, the second chain theoretical length, the acceleration at the current sampling moment and the interval between adjacent sampling moments of the scraper conveyor at the current sampling moment into the observation equation; and using the observation equation to determine the observed chain length of the scraper conveyor at the current sampling moment.

[0018] Optionally, the actual length of the chain of the scraper conveyor is calculated using the following formula:

[0019]

[0020] in, Indicates the actual length of the scraper conveyor chain. Indicates the predicted chain length, Z K represents the length of the observation chain, H represents the observation transfer matrix, K k represents the Kalman gain coefficient; k L Indicates the calibration spacing factor when the chain is not worn, k v Indicates the nominal distance factor when the chain is not worn.

[0021] Thus, an embodiment of the present invention discloses a device for monitoring the chain elongation of a scraper conveyor, wherein the scraper conveyor includes a middle trough body, a motor, a scraper and a chain, the middle trough body includes a shovel side and a baffle side, and the device for monitoring the chain elongation of the scraper conveyor includes: a permanent magnet, a Hall sensor, an encoder, an acceleration sensor and a control device; permanent magnets are fixed on the axes at both ends of the scraper, and the permanent magnets are used to generate a magnetic field at the scraper, and the trough sides on the shovel side and the baffle side of the middle trough body are fixed with Hall sensors, and the Hall sensor is used to collect the magnetic field strength signal of the scraper passing through the Hall sensor when the chain is running; the encoder and the acceleration sensor are both arranged on the motor, the encoder is used to collect the motor speed, and the acceleration sensor is used to collect the motor acceleration; the control device is respectively connected to the Hall sensor, the encoder and the acceleration sensor, and is used to calculate the chain elongation of the scraper conveyor according to the magnetic field strength signal, acceleration and speed.

[0022] Through the technical solution disclosed in the embodiment of the present invention, the combination of permanent magnets and Hall sensors can monitor chain deformation online in real time through non-contact magnetic induction technology. The magnetic field strength signal of the scraper passing by can be continuously captured during the operation of the chain. In combination with the rotation speed collected by the encoder at the motor and the acceleration data obtained by the acceleration sensor, the control device can quickly and accurately calculate the chain elongation, realizing real-time dynamic monitoring of the chain state. Compared with traditional manual detection or other monitoring methods, there is no need to stop the machine for maintenance and the anti-interference performance is strong, which greatly improves the timeliness, accuracy, reliability and detection efficiency of chain elongation monitoring. In addition, the use of multi-dimensional data such as magnetic field strength, motor speed, acceleration for comprehensive calculation can effectively eliminate misjudgments caused by factors such as environmental interference and equipment vibration compared to single parameter monitoring, significantly enhancing the reliability of the monitoring results of chain elongation. Further, the continuous monitoring and calculation of the chain elongation provided by the embodiment of the present invention reduces the frequency and intensity of manual inspections and reduces labor costs. Furthermore, permanent magnets are installed at the axes at both ends of the scraper, and the Hall sensors are fixed on the shovel side and the baffle side of the middle trough body. The Hall sensors have no physical contact with the moving parts, which can avoid mechanical friction or installation offset risks. They have strong impact resistance and can maintain stable detection even in extreme environments such as water splashing, high humidity, and strong vibration in the mine, significantly improving the system's environmental adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a partial structural diagram of a device for monitoring the chain elongation of a scraper conveyor disclosed in an embodiment of the present invention.

[0024] Figure 2 This is a partial structural diagram of another device for monitoring chain elongation of a scraper conveyor disclosed in an embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram of an output signal of a Hall sensor disclosed in an embodiment of the present invention.

[0026] Figure 4 A schematic flow chart of a method for monitoring chain elongation of a scraper conveyor provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] To further illustrate the technical means and effectiveness of the present invention in achieving its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail a method and device for monitoring chain elongation of a scraper conveyor according to the present invention, including its specific implementation, structure, features, and effectiveness. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0028] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0029] The following describes in detail a method and device for monitoring the chain elongation of a scraper conveyor provided by the present invention with reference to the accompanying drawings.

[0030] The embodiment of the present invention discloses a scraper conveyor, which includes a middle trough body, a motor, a scraper and a chain. It is worth noting that the specific structure of the scraper conveyor can refer to the known technology, and the embodiment of the present invention will not be repeated here. Figure 1 and Figure 2 As shown, Figure 1 This is a partial structural diagram of a device for monitoring chain elongation of a scraper conveyor disclosed in an embodiment of the present invention. Figure 2 This is a partial structural diagram of another device for monitoring chain elongation of a scraper conveyor disclosed in an embodiment of the present invention.

[0031] like Figure 1 and Figure 2 As shown, the monitoring device for the chain elongation of the scraper conveyor includes: a permanent magnet 101, a Hall sensor 102, an encoder (not shown in the figure), an acceleration sensor (not shown in the figure) and a control device 103; permanent magnets 101 are fixed on the axes at both ends of the scraper 201, and the permanent magnets 101 are used to generate a magnetic field at the scraper 201. The groove sides on the shovel side and the baffle side of the middle groove body 202 are fixed with Hall sensors. The Hall sensor 102 is used to collect the magnetic field strength signal of the scraper 201 passing through the Hall sensor 102 when the chain 203 is running; the encoder and the acceleration sensor are both provided in the motor, the encoder is used to collect the motor speed, and the acceleration sensor is used to collect the motor acceleration; the control device 103 is connected to the Hall sensor 102, the encoder and the acceleration sensor respectively, and is used to calculate the chain elongation of the scraper conveyor according to the magnetic field strength signal, acceleration and speed.

[0032] Specifically, the scraper 201 conveyor in the embodiment of the present invention includes a central trough body 202, with permanent magnets 101 mounted on the axe heads at each end of the scraper 201. Grooves are formed on the surfaces of the axe heads at both ends of the scraper 201, each of which has a screw hole. Fastening bolts penetrate the permanent magnets 101 and the screw hole to secure the permanent magnets 101 to the grooves. In the embodiment of the present invention, an insulating and shock-absorbing layer is provided at the bottom of the groove. This layer is made of a composite material of nitrile rubber and epoxy resin, with a thickness of 2-3 mm. This layer not only prevents electrochemical corrosion caused by direct contact between the permanent magnets 101 and the metal groove, but also cushions vibrations during operation. The permanent magnets 101 are secured within the grooves by fastening bolts made of 30CrMnSiA alloy steel with a tensile strength of ≥1100 MPa. These bolts, combined with anti-loosening washers and thread lockers, ensure stability under high-frequency vibrations and complex operating conditions. The permanent magnet 101 can be made of NdFeB rare earth permanent magnet material with a remanence strength of ≥1.2T and a coercive force of ≥900kA / m. The surface is treated with epoxy resin coating with a thickness of 50-80μm. It has excellent corrosion resistance and aging resistance and can stably generate a uniform magnetic field.

[0033] Furthermore, the Hall sensor 102 is embedded in the groove of the trough side of the middle trough body 202 and is fastened by fastening bolts. The fastening bolts are flush with the surface of the trough side to avoid interference with the chain operation of the scraper 201 conveyor. Among them, the distance between the shovel side and the baffle side of the middle trough body 202 and the outer sides of the two ends of the scraper 201 is relatively small, generally 7mm-10mm. When the chain is running, the Hall sensor 102 monitors the change in magnetic field strength at the scraper 201 passing through the Hall sensor 102. For example, Figure 3 As shown, Figure 3 A schematic diagram of an output signal of a Hall sensor 102 provided in an embodiment of the present invention, Figure 3 The signal includes both the original signal and the square wave signal. The Hall sensor 102 performs bandpass filtering on the original signal to eliminate the effects of low-frequency vibration and electromagnetic interference. The signal is then reshaped into a square wave signal using a Schmitt trigger. The square wave signal contains time and voltage. The square wave signal is then transmitted to the control device 103 for processing. The control device 103 calculates the time difference Δt between the peak-to-peak values of the adjacent voltages of the square wave. Based on the actual operating speed and acceleration of the chain, the control device 103 calculates the spacing between adjacent scrapers 201 and the displacement of the chain passing through the Hall sensor 102, thereby calculating the chain elongation. It is worth noting that the square wave signal output by the Hall sensor 102 is the magnetic induction intensity signal in this embodiment of the present invention. The peak voltages of the square wave are related to the magnetic induction intensity.

[0034] Furthermore, the embodiment of the present invention determines the monitoring period of the scraper 201 conveyor chain by the number of scrapers 201 of the scraper 201 conveyor. The scraper 201 chain of the scraper 201 conveyor maintains the factory chain length (no chain cutting operation is performed), and the total number of scrapers 201 is equal to the preset value A. A Hall sensor 102 is installed at a specified position of the middle trough body 202 of the scraper 201 conveyor, and the position where the Hall sensor 102 is installed in the middle trough body 202 is used as the reference monitoring point for the operation of the scraper 201 of the scraper 201 conveyor. After the scraper 201 conveyor is powered on, the first scraper 201 that passes the reference monitoring point is marked as the reference scraper 201 (numbered 0), and its position serves as the initial reference point for the chain operation. The physical coordinates of the reference scraper 201 are synchronously recorded with the timestamp in the system database. The system continuously monitors the number of scrapers 201 that pass the reference monitoring point, and a count is triggered every time a scraper 201 is detected (the cumulative value is recorded as N). When the cumulative count satisfies N = A, the chain of the scraper 201 conveyor is determined to have completed a full closed-loop operation cycle, and a cycle completion signal is generated. Since the axe heads at both ends of the scraper 201 are mounted with permanent magnets 101, each time the scraper 201 passes through the Hall sensor 102, it triggers the Hall sensor 102 to output a magnetic induction intensity signal. The output time of the magnetic induction intensity signal is the sampling moment when the scraper 201 passes the Hall sensor 102, which corresponds to one count.

[0035] Furthermore, as the chain drives the scraper 201 through its circulation within the central trough 202, the permanent magnet 101 affixed to the scraper 201 moves accordingly, and the Hall effect sensor 102 continuously collects magnetic field intensity signals passing through the scraper 201. Chain elongation causes the spacing between the scrapers 201 to change, which in turn changes the time interval between adjacent permanent magnets 101 passing through the Hall effect sensor 102, and the periodic characteristics of the magnetic field intensity signal also change accordingly. Therefore, in this embodiment of the present invention, chain elongation is determined based on the time interval between adjacent scrapers 201 and the corresponding periodic characteristics of the magnetic induction intensity signal.

[0036] Furthermore, the Hall sensor 102 converts the collected analog signal into a digital signal, and transmits the digital signal to the control device 103 via an industrial communication protocol, which may be an RS485 bus.

[0037] Furthermore, the encoder installed inside the motor collects the motor's speed data in real time through photoelectric induction or magnetoelectric induction. In the embodiment of the present invention, the encoder can use an incremental rotary encoder. The acceleration sensor can accurately measure the acceleration changes during the operation of the motor, and the built-in low-pass filter can eliminate high-frequency noise interference. The data collected by both the encoder and the acceleration sensor can be transmitted to the control device 103 via the CAN bus. The control device 103 has a built-in high-precision data processing module and algorithm program, which first performs Kalman filtering on the magnetic field strength signal transmitted by the Hall sensor 102 to eliminate environmental electromagnetic interference. The filter bandwidth is 0.1-50Hz. The chain elongation is then calculated by combining the motor speed data provided by the encoder with the acceleration data obtained by the acceleration sensor.

[0038] Further, such as Figure 2 As shown, the monitoring device for the chain elongation of the scraper conveyor also includes: an automatic chain tensioning valve group 104, which is respectively connected to the tail of the scraper conveyor and the control device 103; when the chain elongation exceeds a first threshold value, the control device 103 controls the extension cylinder of the automatic chain tensioning valve group 104 to drive the tail of the scraper conveyor to extend through the piston rod of the automatic chain tensioning valve group 104 to tension the chain 203, and the length of the extended tail of the scraper conveyor is half of the chain elongation.

[0039] Specifically, in the embodiment of the present invention, the initial reference value of the displacement sensor of the automatic chain tensioning valve assembly 104 is S0, corresponding to the standard factory chain length L0. When the load of the scraper conveyor increases, the chain elastically deforms, resulting in a chain extension of ΔL (ΔL = upper chain extension + lower chain extension). At this time, the control device 103 detects that the chain extension ΔL exceeds a first threshold value, and determines that the chain is loose. The control device 103 controls the automatic chain tensioning valve assembly 104 to extend the cylinder, thereby driving the tail of the scraper conveyor to extend through the piston rod of the automatic chain tensioning valve assembly 104 to tension the chain. The displacement sensor of the oil cylinder of the automatic chain tensioning valve assembly 104 can control the piston rod to extend a compensation stroke of ΔL / 2, that is, the length of the scraper conveyor tail extension is ΔL / 2. In this way, when the chain elongation exceeds a first threshold, control device 103 immediately triggers the automatic chain tensioning valve assembly, pushing the tailpiece out via a piston rod to compensate for chain slack in real time. This eliminates the lag associated with manual intervention, ensures the chain maintains proper tension, and effectively reduces the probability of faults such as chain skipping and chain breakage. The tailpiece extension is designed to be half the chain elongation. This "half-compensation" approach eliminates chain slack while preventing increased chain fatigue caused by overtension. By precisely regulating chain tension, the force applied to each part of the chain is more evenly distributed, significantly extending chain life and reducing equipment maintenance costs.

[0040] Furthermore, when the load on the scraper conveyor is released, the chain's elastic deformation recovers, reducing the total elongation to ΔL' (ΔL' < ΔL). After the control device 103 determines that the chain is over-tensioned, it controls the automatic chain tensioning valve assembly 104 to retract its piston rod, causing the scraper conveyor's tail section to retract and loosen the chain. The control cylinder then precisely retracts according to a pre-set algorithm. This entire control process is linked to a pre-set tension model through real-time feedback from the displacement sensor to dynamically maintain optimal chain tension.

[0041] Furthermore, as an optional embodiment of the present invention, the permanent magnet has two poles, an N pole and an S pole, and the polarity of the poles on the two opposite sides of the permanent magnets on adjacent scrapers is opposite. That is, if one side of the permanent magnet of one of the adjacent scrapers is an N pole, the magnetic pole on the opposite side of the permanent magnet of the other adjacent scraper is an S pole; if one side of the permanent magnet of one of the adjacent scrapers is an S pole, the magnetic pole on the opposite side of the permanent magnet of the other adjacent scraper is an N pole. In this way, the embodiment of the present invention adopts a method of alternating the polarity of the permanent magnets to form a stable magnetic field interaction between adjacent scrapers, avoid crosstalk between adjacent magnetic signals, improve the resolution of the Hall sensor, ensure the regularity and functionality of the magnetic force distribution when the chain is running, improve the stability and accuracy of the magnetic field intensity signal collected by the Hall sensor, and thus improve the monitoring accuracy of the chain elongation. In addition, a permanent magnet marker group with alternating N / S poles is embedded at specific pitches of the chain. An independent magnetic code element structure is constructed through the discrete design of the magnetic pole polarity direction and spacing. Combined with differential signal processing technology, electromagnetic noise interference is suppressed, so that the spatial resolution of the magnetic marker reaches ±2mm, and tiny deformations of adjacent chain links are accurately identified, avoiding the crosstalk problem that is prone to occur with traditional unipolar magnetic markers from the signal source.

[0042] It is worth noting that in the embodiment of the present invention, Hall sensors are installed on the side groove of the baffle and the measuring groove of the shovel plate, which can monitor not only a single chain but also a double chain. By fusing the Hall sensor data on both sides and using the Kalman filter algorithm, the measurement error caused by the lateral swing of the chain can be eliminated.

[0043] Through the technical solution disclosed in the embodiment of the present invention, the combination of permanent magnets and Hall sensors can monitor chain deformation online in real time through non-contact magnetic induction technology. The magnetic field strength signal of the scraper passing by can be continuously captured during the operation of the chain. In combination with the rotation speed collected by the encoder at the motor and the acceleration data obtained by the acceleration sensor, the control device can quickly and accurately calculate the chain elongation, realizing real-time dynamic monitoring of the chain state. Compared with traditional manual detection or other monitoring methods, there is no need to stop the machine for maintenance and the anti-interference performance is strong, which greatly improves the timeliness, accuracy, reliability and detection efficiency of chain elongation monitoring. In addition, the use of multi-dimensional data such as magnetic field strength, motor speed, acceleration for comprehensive calculation can effectively eliminate misjudgments caused by factors such as environmental interference and equipment vibration compared to single parameter monitoring, significantly enhancing the reliability of the monitoring results of chain elongation. Further, the continuous monitoring and calculation of the chain elongation provided by the embodiment of the present invention reduces the frequency and intensity of manual inspections and reduces labor costs. Furthermore, permanent magnets are installed at the axes at both ends of the scraper, and the Hall sensors are fixed on the shovel side and the baffle side of the middle trough body. The Hall sensors have no physical contact with the moving parts, which can avoid mechanical friction or installation offset risks. They have strong impact resistance and can maintain stable detection even in extreme environments such as water splashing, high humidity, and strong vibration in the mine, significantly improving the system's environmental adaptability.

[0044] Based on the same inventive concept, an embodiment of the present invention further provides a method for monitoring the chain elongation of a scraper conveyor, which is based on the monitoring device for the chain elongation of the scraper conveyor in the above embodiment, such as Figure 4 As shown, Figure 4 A flow chart of a method for monitoring chain elongation of a scraper conveyor provided in an embodiment of the present invention includes the following steps:

[0045] Step S401 : When the chain of the scraper conveyor is running, a magnetic induction intensity signal of the scraper passing through the Hall sensor, and a rotation speed and acceleration of a motor of the scraper conveyor are obtained.

[0046] Specifically, as in the above-described embodiment, each scraper of the scraper conveyor is mounted with a permanent magnet. A stable magnetic field is formed between the oppositely polarized permanent magnets on the opposing sides of adjacent scrapers. When a scraper passes a Hall sensor, the Hall sensor triggers the output of a magnetic induction intensity signal. The time interval between adjacent scrapers can be the difference in the time instants when the Hall sensor outputs the magnetic induction intensity signal. The speed of the scraper conveyor's motor can be monitored in real time by the encoder of the device in the above-described embodiment, and the acceleration of the motor can be measured by the acceleration sensor of the device in the above-described embodiment.

[0047] Step S402 : predicting the chain length at the current sampling moment based on the theoretical length of the first chain of the scraper conveyor passing the Hall sensor at the previous sampling moment, the rotation speed and the acceleration of the motor.

[0048] Specifically, the first theoretical length of the chain of the scraper conveyor that passes through the Hall sensor at the last sampling moment refers to the theoretical length of the chain calculated from the time corresponding to the scraper passing through the reference monitoring point to the scraper passing at the last sampling moment and the chain speed. There are two cases when calculating the first theoretical length of the chain. First, the motor speed is a constant, that is, the chain rotates at a constant speed. Second, the motor speed changes, that is, the chain rotates at a uniform speed. When the motor speed is a constant, the chain speed of the scraper conveyor is calculated using the speed, the speed ratio of the scraper conveyor's reducer, the number of sprocket teeth of the scraper conveyor, and the chain pitch. The first and second moments when the permanent magnets of each adjacent scraper trigger the magnetic induction intensity signal generated by the Hall sensor are calculated. Based on the first and second moments and the chain speed, the first theoretical length of the scraper conveyor when it moves at a uniform speed is determined. When the motor speed changes uniformly, the initial chain speed of the chain is obtained when the motor speed begins to change. Based on the first moment, the second moment, the acceleration of the scraper conveyor motor between the first and second moments, and the initial chain speed, the theoretical length of the first chain of the scraper conveyor during uniformly variable speed motion is determined. The last second moment is the previous sampling moment.

[0049] Specifically, the chain speed of the scraper conveyor in the embodiment of the present invention is calculated using the following formula:

[0050]

[0051] Among them, v represents the chain speed of the scraper conveyor, n represents the speed of the motor of the scraper conveyor, i represents the speed ratio of the reducer of the scraper conveyor, Z represents the number of sprocket teeth of the scraper conveyor, and P represents the chain pitch.

[0052] Furthermore, when the chain rotates at a constant speed, the theoretical length of the first chain is calculated using the following formula:

[0053] Where Δt = t2 - t1

[0054] In the above formula, L t represents the theoretical length of the first chain. t2 represents the second moment, and t1 represents the first moment. Δt represents the time interval between adjacent scrapers passing the Hall effect sensor. v(t) represents the chain speed at moment t.

[0055] Furthermore, when the chain moves at a uniform speed, the theoretical length of the first chain is calculated using the following formula:

[0056]

[0057] In the above formula, L t represents the theoretical length of the first chain. Δt represents the time interval between adjacent scrapers passing the Hall effect sensor. v0 represents the initial chain speed when the motor speed begins to change. a represents the acceleration of the motor.

[0058] Furthermore, as an optional embodiment of the present invention, predicting the predicted chain length at the current sampling moment based on the theoretical length of the first chain of the chain passing through the Hall sensor at the previous sampling moment of the scraper conveyor, the speed of the motor, and the acceleration includes: determining the chain speed of the scraper conveyor at the previous sampling moment based on the speed of the motor; substituting the chain speed of the scraper conveyor at the previous sampling moment, the theoretical length of the first chain, the acceleration, and the interval between adjacent sampling moments into a state equation; and predicting the predicted chain length at the current sampling moment using the state equation;

[0059] Specifically, the state equation in the embodiment of the present invention is expressed as follows:

[0060]

[0061] In the above formula, X k The predicted chain length and predicted chain speed of the scraper conveyor at the kth moment are represented by the state parameters. Δt represents the time interval between adjacent scrapers passing through the Hall sensor. L k-1 Indicates the theoretical length of the first chain at the previous sampling time k-1 at the kth time. k-1 Indicates the chain speed at the previous sampling moment k-1 before the kth moment. k-1 w represents the acceleration of the motor at the previous sampling moment k-1 before the kth moment. k Indicates the data error caused by vibration and slippage during chain operation. k )~N(0,Q), that is, w k Obeying normal distribution, covariance matrix σ L It represents the standard deviation of the error between the predicted chain length and the actual chain length during the chain's historical operation, σ v It represents the standard deviation of the error between the predicted chain speed and the actual chain speed during the chain's historical operation.

[0062] By bringing the chain speed, theoretical length of the first chain, acceleration and the interval between adjacent sampling moments of the scraper conveyor at the previous sampling moment into the above state equation, the predicted chain length at the current sampling moment k can be predicted.

[0063] Furthermore, the state equation in the embodiment of the present invention can also be rewritten as follows:

[0064]

[0065] in, Indicates the prediction chain length at the current sampling moment. Indicates the theoretical length of the first chain at the last sampling moment. k Indicates the chain speed at the current sampling moment.

[0066] When using the predicted chain length to calculate the actual length of the scraper conveyor chain, you can use X k The state parameter L k As You can also use it directly Predicted

[0067] Step S403 : determining the observed chain length at the current sampling moment according to the theoretical length of the second chain of the chain passing through the Hall sensor at the current sampling moment, the rotation speed and the acceleration of the motor.

[0068] The theoretical length of the chain is determined by the moment when the permanent magnet of the scraper passes through the Hall sensor, triggering the magnetic induction intensity signal generated by the Hall sensor.

[0069] Specifically, the calculation method of the theoretical length of the second chain can refer to the calculation method of the theoretical length of the first chain in the above embodiment, and the embodiment of the present invention will not be repeated here.

[0070] Furthermore, as an optional embodiment of the present invention, determining the observed chain length at the current sampling moment based on the theoretical length of the second chain of the chain passing through the Hall sensor at the current sampling moment, the speed of the motor, and the acceleration includes: determining the chain speed of the scraper conveyor at the current sampling moment based on the speed of the motor; substituting the chain speed of the scraper conveyor at the current sampling moment, the theoretical length of the second chain, the acceleration at the current sampling moment, and the interval between adjacent sampling moments into the observation equation; and using the observation equation to determine the observed chain length of the scraper conveyor at the current sampling moment.

[0071] Specifically, the observation equation in the embodiment of the present invention can be expressed as follows:

[0072]

[0073] In the above formula, Z k Represents the observed chain length L of the scraper conveyor at the current sampling time k L,k and observed chain speed v L,k The state parameter. k Indicates the acceleration of the motor at the current sampling time k. kRepresents the observation noise, that is, the observation error of the Hall sensor. Among them, p(n k )~N(0,R), indicating that the observation error of the Hall sensor conforms to the normal distribution, R represents the observation noise, σ L,obs represents the standard deviation of the error between the observed chain length and the actual chain length, σ v,obs It represents the standard deviation of the error between the observed chain speed and the actual chain speed. Δt represents the time interval between the adjacent sampling moments when the scrapers pass through the Hall sensor. Indicates the theoretical length of the second chain. Indicates the chain speed at the current sampling moment, which can be calculated using the above chain speed calculation formula.

[0074] Through the above observation equation, the observed chain length L of the scraper conveyor at the current sampling time can be obtained: L,k .

[0075] Step S404: determining the actual chain length of the scraper conveyor based on the predicted chain length and the observed chain length of the scraper conveyor, and determining the difference between the actual chain length and the initial chain length of the scraper conveyor as the chain elongation of the scraper conveyor.

[0076] Specifically, the embodiment of the present invention uses the predicted chain length and the observed chain length to calculate the actual chain length. As an optional embodiment of the present invention, the actual chain length of the scraper conveyor is calculated using the following formula:

[0077]

[0078] in, Indicates the actual length of the scraper conveyor chain. Indicates the predicted chain length, Z K Indicates the length of the observation chain (it is worth noting that Z is used in the embodiment of the present invention K L in L,k ), H represents the observation transfer matrix, K k represents the Kalman gain coefficient; k L Indicates the calibration spacing factor when the chain is not worn, k v The calibration distance coefficient represents the calibration distance coefficient when the chain is not worn. The calibration spacing coefficient and the calibration distance coefficient can be determined according to actual conditions and are not limited in this embodiment of the present invention.

[0079] Furthermore, K in the embodiment of the present invention k It can be dynamically determined based on the predicted covariance of the state equation and the observation noise R. The predicted covariance in the embodiment of the present invention is expressed as follows through the above state equation:

[0080] P k =AP K-1 A T +Q

[0081] In the above formula, P k P represents the prediction covariance at the current sampling time k. K-1 represents the predicted covariance at the previous sampling time k-1. Q represents the covariance matrix in the above embodiment. A T represents the transpose of A.

[0082] Furthermore, K k Specifically, it can be calculated using the following formula:

[0083] K k =P k H T (HP k H T +R) -1

[0084] In the above formula, K k Represents the Kalman gain coefficient. P k represents the predicted covariance at the current sampling time k. represents the observation noise. H represents the observation transfer matrix, H T represents the transpose of H.

[0085] Through the technical solution disclosed in the embodiment of the present invention, the combination of a permanent magnet and a Hall sensor can continuously capture the magnetic field strength signal when the scraper passes by during the operation of the chain. In conjunction with the rotation speed collected by the encoder at the motor and the acceleration data obtained by the acceleration sensor, the control device can quickly and accurately calculate the chain elongation, realizing real-time dynamic monitoring of the chain state. Compared with traditional manual detection or other monitoring methods, there is no need to stop the machine for maintenance and the degree of environmental influence is small, which greatly improves the timeliness, accuracy, reliability and detection efficiency of the chain elongation monitoring. In addition, the use of multi-dimensional data such as magnetic field strength, motor speed, acceleration for comprehensive calculation can effectively eliminate misjudgments caused by factors such as environmental interference and equipment vibration compared to single parameter monitoring, significantly enhancing the reliability of the monitoring results of the chain elongation. Further, the continuous monitoring and calculation of the chain elongation provided by the automated embodiment of the present invention reduces the frequency and intensity of manual inspections and reduces labor costs.

[0086] Furthermore, in order to improve the accuracy of the status monitoring of the scraper conveyor chain, the embodiment of the present invention also calculates the chain elongation of the scraper conveyor chain. As an optional embodiment of the present invention, when the scraper conveyor chain is running, after obtaining the magnetic induction intensity signal of the scraper passing through the Hall sensor, the speed and acceleration of the scraper conveyor motor, the method further includes:

[0087] When the motor speed is a constant, the chain speed of the scraper conveyor is calculated using the speed, the speed ratio of the scraper conveyor's reducer, the number of sprocket teeth of the scraper conveyor, and the chain pitch; the first and second moments when the permanent magnets of adjacent scrapers trigger the magnetic induction intensity signals generated by the Hall sensor are calculated; the theoretical length of the chain when the scraper conveyor moves at a constant speed is determined based on the first and second moments and the chain speed; when the motor speed changes at a constant speed, the initial chain speed of the chain when the motor speed starts to change is obtained; the theoretical length of the chain when the scraper conveyor moves at a uniform speed is determined based on the first and second moments, the acceleration of the scraper conveyor's motor between the first and second moments, and the initial chain speed; the chain elongation of the scraper conveyor is determined based on the theoretical length of the chain, the initial length of the distance between the center points of adjacent chain links corresponding to adjacent scrapers, and the number of scrapers passing through the Hall sensor.

[0088] Specifically, the chain speed of the scraper conveyor in the embodiment of the present invention is calculated using the following formula:

[0089]

[0090] Among them, v represents the chain speed of the scraper conveyor, n represents the speed of the motor of the scraper conveyor, i represents the speed ratio of the reducer of the scraper conveyor, Z represents the number of sprocket teeth of the scraper conveyor, and P represents the chain pitch.

[0091] Furthermore, when the chain rotates at a constant speed, the theoretical length of the chain is calculated using the following formula:

[0092] Where Δt = t2 - t1

[0093] In the above formula, L t represents the theoretical length of the chain. t2 represents the second moment, and t1 represents the first moment. Δt represents the time interval between adjacent scrapers passing the Hall effect sensor. v(t) represents the chain speed at moment t.

[0094] Furthermore, when the chain moves at a uniform speed, the theoretical length of the chain is calculated using the following formula:

[0095]

[0096] In the above formula, L trepresents the theoretical length of the first chain. Δt represents the time interval between adjacent scrapers passing the Hall effect sensor. v0 represents the initial chain speed when the motor speed begins to change. a represents the acceleration of the motor.

[0097] Furthermore, as an optional embodiment of the present invention, the chain elongation of the scraper conveyor is calculated using the following formula:

[0098]

[0099] Among them, δ represents the chain elongation of the scraper conveyor, L t represents the theoretical length of the chain, N represents the number of scrapers passing through the Hall sensor, and L0 represents the initial length of the distance between the center points of adjacent chain links corresponding to adjacent scrapers.

[0100] Furthermore, after calculating the chain elongation, when the chain elongation exceeds the second threshold, the control device controls the chain automatic tensioning valve group to extend the cylinder to drive the tail of the scraper conveyor to extend through the piston rod of the chain automatic tensioning valve group to tension the chain. The length of the extended tail of the scraper conveyor is half of the chain elongation.

[0101] It should be noted that the method for monitoring the chain elongation of a scraper conveyor provided in an embodiment of the present invention and the device for monitoring the chain elongation of a scraper conveyor in the above-mentioned embodiment are based on the same application concept. The same or similar specific implementations of the two embodiments can be referenced to each other, and have the same or similar beneficial effects, and the repeated parts will not be repeated.

[0102] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0103] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A monitoring device for the chain elongation of a scraper conveyor, wherein the scraper conveyor comprises a middle trough body, a motor, a scraper and a chain, wherein the middle trough body comprises a shovel plate side and a baffle plate side, and wherein: The monitoring device for the chain elongation of the scraper conveyor includes: a permanent magnet, a Hall sensor, an encoder, an acceleration sensor and a control device; The axe heads at both ends of the scraper are fixed with the permanent magnets, and the permanent magnets are used to generate a magnetic field at the scraper. The groove sides on the shovel plate side and the groove sides on the baffle side of the middle groove body are fixed with the Hall sensors, and the Hall sensors are used to collect the magnetic field strength signal of the scraper passing through the Hall sensors when the chain is running; The encoder and the acceleration sensor are both provided on the motor, the encoder is used to collect the rotation speed of the motor, and the acceleration sensor is used to collect the acceleration of the motor; The control device is connected to the Hall sensor, the encoder and the acceleration sensor respectively, and is used to calculate the chain elongation of the scraper conveyor according to the magnetic field strength signal, the acceleration and the rotation speed.

2. The monitoring device for chain elongation of a scraper conveyor according to claim 1, characterized in that: The monitoring device for the chain elongation of the scraper conveyor further comprises: an automatic chain tensioning valve group, the automatic chain tensioning valve group being connected to the tail of the scraper conveyor and the control device respectively; When the chain elongation exceeds a first threshold value, the control device controls the extension cylinder of the chain automatic tensioning valve group to drive the tail of the scraper conveyor to extend through the piston rod of the chain automatic tensioning valve group to tension the chain. The length of the extended tail of the scraper conveyor is half of the chain elongation.

3. The monitoring device for chain elongation of a scraper conveyor according to claim 1, characterized in that: Grooves are formed on the axe surfaces at both ends of the scraper, and screw holes are formed in the grooves; A fastening bolt passes through the permanent magnet and the screw hole to fix the permanent magnet to the groove.

4. The monitoring device for chain elongation of a scraper conveyor according to claim 1, characterized in that: The permanent magnet has two magnetic poles, an N pole and an S pole. The polarities of the magnetic poles on two opposite sides of the permanent magnets on adjacent scrapers are opposite.

5. A method for monitoring the chain elongation of a scraper conveyor, characterized in that: The device for monitoring the chain elongation of a scraper conveyor according to any one of claims 1 to 4 comprises: When the chain of the scraper conveyor is running, obtaining the magnetic induction intensity signal of the scraper passing through the Hall sensor, the speed and acceleration of the motor of the scraper conveyor; Predicting the predicted chain length at the current sampling moment based on the theoretical length of the first chain of the scraper conveyor passing through the Hall sensor at the previous sampling moment, the speed and acceleration of the motor; Determining the observed chain length at the current sampling moment based on the theoretical length of the second chain of the chain passing through the Hall sensor at the current sampling moment, the rotational speed of the motor, and the acceleration, wherein the theoretical chain length is determined by the moment corresponding to the magnetic induction intensity signal generated by the Hall sensor when the permanent magnet of the scraper passes through the Hall sensor; The actual chain length of the scraper conveyor is determined based on the predicted chain length of the scraper conveyor and the observed chain length, and the difference between the actual chain length and the initial chain length of the scraper conveyor is determined as the chain elongation of the scraper conveyor.

6. The method for monitoring the chain elongation of a scraper conveyor according to claim 5, characterized in that: When the chain of the scraper conveyor is running, after obtaining the magnetic induction intensity signal of the scraper passing through the Hall sensor, the speed and acceleration of the motor of the scraper conveyor, the method further includes: When the rotation speed of the motor is a constant value, the chain speed of the scraper conveyor is calculated using the rotation speed, the speed ratio of the reducer of the scraper conveyor, the number of sprocket teeth of the scraper conveyor, and the chain pitch; Calculating the first moment and the second moment when the permanent magnets of the adjacent scrapers trigger the magnetic induction intensity signal generated by the Hall sensor; Determining a theoretical chain length of the scraper conveyor when the scraper conveyor moves at a uniform speed based on each of the first moment, the second moment, and the chain speed; When the rotation speed of the motor changes at a constant speed, obtaining the initial chain speed of the chain when the rotation speed of the motor starts to change; Determining a theoretical chain length of the scraper conveyor during uniformly variable speed motion based on the first moment, the second moment, the acceleration of the motor of the scraper conveyor between the first moment and the second moment, and the initial chain speed; The chain elongation of the scraper conveyor is determined according to the theoretical length of the chain, the initial length of the distance between the center points of adjacent chain links corresponding to the adjacent scrapers, and the number of scrapers passing through the Hall sensor.

7. The method for monitoring the chain elongation of a scraper conveyor according to claim 6, characterized in that: The chain speed of the scraper conveyor is calculated using the following formula: Among them, v represents the chain speed of the scraper conveyor, n represents the speed of the motor of the scraper conveyor, i represents the speed ratio of the reducer of the scraper conveyor, Z represents the number of sprocket teeth of the scraper conveyor, and P represents the chain pitch.

8. The method for monitoring the chain elongation of a scraper conveyor according to claim 6, characterized in that: The chain elongation of the scraper conveyor is calculated using the following formula: Among them, δ represents the chain elongation of the scraper conveyor, L t represents the theoretical length of the chain, N represents the number of scrapers passing through the Hall sensor, and L0 represents the initial length of the distance between the center points of adjacent chain links corresponding to adjacent scrapers.

9. The method for monitoring the chain elongation of a scraper conveyor according to claim 5, characterized in that: The predicting of the chain length at the current sampling moment according to the theoretical length of the first chain of the scraper conveyor passing through the Hall sensor at the previous sampling moment, the rotation speed and the acceleration of the motor includes: Determining the chain speed of the scraper conveyor at the last sampling moment according to the rotation speed of the motor; Substitute the chain speed of the scraper conveyor at the last sampling moment, the theoretical length of the first chain, the acceleration, and the interval between adjacent sampling moments into the state equation; Predicting the predicted chain length at the current sampling moment using the state equation; Determining the observed chain length at the current sampling moment according to the second chain theoretical length of the chain passing through the Hall sensor at the current sampling moment, the speed and acceleration of the motor includes: Determining the chain speed of the scraper conveyor at a current sampling moment according to the rotational speed of the motor; Substitute the chain speed of the scraper conveyor at the current sampling moment, the theoretical length of the second chain, the acceleration at the current sampling moment, and the interval between adjacent sampling moments into the observation equation; The observation equation is used to determine the observation chain length of the scraper conveyor at the current sampling moment.

10. The method for monitoring chain elongation of a scraper conveyor according to claim 5, characterized in that: The actual length of the chain of the scraper conveyor is calculated using the following formula: in, Indicates the actual length of the scraper conveyor chain. Indicates the predicted chain length, Z K represents the length of the observation chain, H represents the observation transfer matrix, K k represents the Kalman gain coefficient; k L Indicates the calibration spacing factor when the chain is not worn, k v Indicates the nominal distance factor when the chain is not worn.

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