A control system for improving the accuracy of belt scales under harsh working conditions and its control method

Abstract

The present invention provides a control system for improving the accuracy of belt scales under harsh working conditions. The belt scale at the tunneling point is installed on the tunneling conveyor belt at the tunneling point, and transmits the signal and the corresponding speed signal to the central controller together; the main belt scale is installed on the main conveyor belt following the tunneling conveyor belt, and transmits the flow signal and the corresponding speed signal to the central controller together; the central controller collects the weight, flow and speed signals sent by the belt scale at the tunneling point and the main belt scale, obtains the corrected flow signal of the belt scale at the tunneling point, and sends it to the upper-level control computer to realize the output of the accurate flow value of the belt scale at the tunneling point immediately. In the present invention, the belt scale at the tunneling point in front adopts a single-point suspended weighing unit in the array belt scale, and the subsequent main belt scale adopts an array belt scale. According to the function of learning and correcting the "voltage-flow" curve of the system, the measurement accuracy of the simple belt scale in front can reach that the weighing accuracy is less than 0.5%.

Description

Technical Field

[0001] The present invention relates to a belt scale control device, specifically a control system for improving the accuracy of belt scales under harsh working conditions, belonging to the technical field of belt scale calibration equipment. Background Art

[0002] During the conveying process of bulk materials, it is often necessary to measure the conveyed materials. In some application scenarios, due to limited on-site process conditions, the working conditions are often harsh, the equipment space is narrow, large-scale measuring devices cannot be installed, and stable usage conditions for measuring devices are not available.

[0003] In order to save energy, modern coal mines often use frequency conversion control for the main coal conveying belt underground to control the belt running speed according to the amount of coal conveyed. Since the driving motor capacity of this belt conveyor is large, often reaching several thousand KW, reducing the high-speed operation of the belt during empty belt or small coal volume has great economic significance for energy conservation and reducing belt conveyor wear. The key requirement of this technology is to predict in advance the amount of coal coming from each coal mining and tunneling point, so as to timely adjust the belt speed, ensure that all the incoming coal is sent away in time, prevent accidents such as the belt conveyor being buried due to too late speed adjustment, and operate at a reasonable speed to achieve the energy-saving goal.

[0004] At each mining and excavation point, the roadheader is constantly moving, and the following conveyor belt adopts a simple structure, has no fixed foundation, and the working face site is narrow. Limited by on-site conditions, the currently more feasible method is to install a belt scale on this belt conveyor for measurement. However, due to the narrow site, only a simple belt scale can be installed. Under such harsh working conditions, this belt scale cannot be used normally, let alone guarantee the detection accuracy. Therefore, the coal conveying volume at this point can never be measured, resulting in the main coal belt conveyor of the coal mine having to operate at the highest speed to adapt to the maximum incoming coal transportation, leading to huge waste.

[0005] There are many other scenarios of bulk material conveying similar to the above situation, where accurate measurement is required, but installation of measuring equipment is restricted by conditions. The common feature of these scenarios is that it is necessary to obtain measurement data nearby, but installation of measuring equipment is restricted by conditions.

[0006] The current status of detection technology is that the common methods for detecting the weight during the continuous operation of bulk materials are as follows:

[0007] ⑴ Nuclear scale: Install a radiation source and a receiver at the place where the belt material passes, and calculate the mass of the passing material by detecting the attenuation rate of the radiation dose caused by the absorption of the material. This device requires the use of a radiation source, and its detection accuracy is related to the material composition of the material. It needs to be frequently calibrated and verified, which is very troublesome. Therefore, it is very unsafe and inconvenient to use in these scenarios, and the accuracy is not high. There is no application report in this regard either.

[0008] ⑵ Impact scale: A hopper is set up, and by detecting the impact force generated when the material enters the hopper, the amount of the material is deduced. This method requires that the physical properties of the measured material must be stable, such as the particle size and speed must be consistent, and the device needs to be precisely installed and calibrated. Otherwise, the accuracy cannot be guaranteed, and no reported cases of actual application are available.

[0009] ⑶ Belt scale: A belt scale is installed on the belt conveyor near the incoming material point to measure the material passing through the belt scale. This solution is relatively practical and has been used by users. However, the belt scale has high requirements for the use environment, especially requiring the belt conveyor itself to be in good working condition; affected by the harsh use environment, the belt scale needs to be maintained and calibrated frequently to ensure normal use; due to the harsh on-site conditions, this requirement is difficult to guarantee, restricting the use of the belt scale under such conditions.

[0010] In summary, there are great difficulties in the material transportation measurement near the coal mine heading point. Technically, it is most likely to use a belt scale, and there are many implementation cases. However, the key problem is how to maintain the measurement accuracy under such harsh working conditions. Summary of the Invention

[0011] In view of the above-mentioned technical problems, the present invention provides a control system for improving the accuracy of a belt scale under harsh working conditions. It adopts a dual-scale and self-learning mode to form a new belt scale weighing system, which can effectively solve the problem of accurate weighing of the belt scale under harsh working conditions.

[0012] The technical solution of the present invention to solve the above technical problems is: to provide a control system for improving the accuracy of a belt scale under harsh working conditions, including a heading point belt scale, a main belt scale, and a central controller;

[0013] The heading point belt scale is installed on the heading conveyor belt at the heading point, and nearby collects the weight signal of the conveyed material, and transmits the signal and the corresponding speed signal to the central controller together;

[0014] The main belt scale is installed on the main conveyor belt following the heading conveyor belt, accurately collects the weight of the conveyed material, and transmits the accurate flow signal and the corresponding speed signal to the central controller together;

[0015] The central controller is an independent computer or its function is integrated into the instrument of the belt scale. It collects the weight, flow, and speed signals sent by the heading point belt scale and the main belt scale, and calculates according to the learning model in the central controller to obtain the corrected flow signal of the heading point belt scale, and sends it to the upper-level control computer to realize the output of the accurate flow value of the heading point belt scale in real time.

[0016] A further limited technical solution of the present invention is that in the control system for improving the accuracy of belt scales under harsh working conditions, the belt scale at the tunneling point adopts a single-point suspended weighing unit in an array belt scale; the main belt scale adopts an array belt scale.

[0017] The belt scale at the tunneling point adopts a single-point suspended weighing unit in an array belt scale, and relatively stable signals can be obtained. These signals have relative stability within a short period of time, and the variations are within the allowable range. Usually, the lag time for materials to reach the main belt scale from the tunneling point is from dozens of seconds to several minutes. Through this learning process of delay, the "voltage - flow" curve originally stored in the belt scale at the tunneling point can be corrected in a timely manner, so that the weighing accuracy of the belt scale at the tunneling point continuously approaches and follows the accuracy of the main belt scale, thus achieving the effect of high-precision weighing for a simple belt scale under harsh environments.

[0018] The working environment of the belt scale at the tunneling point restricts it from having the basic working conditions of a belt scale, such as it being impossible to calibrate the tare weight of the belt scale and the floating of the belt conveyor foundation, etc.; at this time, the belt scale at the tunneling point becomes a weight signal detector, which only responsible for finding the corresponding flow value according to the weight signal voltage value and outputting it to the central control computer. And the accuracy of the weight depends on the accurate measurement of the main belt scale and the learning of the curve. That is, the working mode of the belt scale at the tunneling point has undergone a fundamental change, and a brand-new intelligent weighing system including the belt scale at the tunneling point, the main belt scale, and the entire closed-loop learning system is formed with the goal of improving the weighing accuracy of belt scales under harsh environments.

[0019] A control method for a control system for improving the accuracy of belt scales under harsh working conditions includes the following steps:

[0020] (1) Install a belt scale at the tunneling point on the belt at the tunneling point, and the belt scale at the tunneling point detects the weight signal voltage at the moment when the material passes through;

[0021] (2) Preset a "voltage - flow" curve in the belt scale at the tunneling point. According to the weight signal voltage detected by the belt scale at the tunneling point, the corresponding flow value can be obtained directly by looking up the curve match, and the matched flow value is sent to the central controller for frequency conversion control of the main belt;

[0022] (3) The weight signal voltage at the moment when the belt scale at the tunneling point detects the material passing through is pushed into the system stack of the central controller at the same time;

[0023] (4) The material at the aforementioned moment passes through the conveyor belt and enters the main belt scale after a period of delay, and the accurate weight and corresponding flow value at this moment can be obtained. At this time, find out the weight signal voltage value corresponding to the moment detected by the belt scale at the tunneling point from the system stack for comparison, and the correct "voltage - flow" ratio curve at the moment can be obtained;

[0024] (5) Modify the preset "voltage - flow" curve existing in the belt scale at the tunneling point, and re - inject the modified "voltage - flow" curve into the belt scale at the tunneling point;

[0025] (6) By detecting and modifying different points, the preset "voltage - flow" curve in the belt scale at the tunneling point can be continuously modified, thus realizing the learning cycle of the system.

[0026] For the control method of the control system for improving the accuracy of the belt scale under harsh working conditions described above, when initially establishing the "voltage - flow" curve with only one instantaneous point, the other points on the curve can all use the same value as the initial value. When the same (or approximate) value as a certain point appears again during the system operation, it can be updated, and the gap between two points can be connected by a straight line or a smooth transition algorithm to form a complete curve. Since the weighing slope of the belt scale is approximately linear within a certain range, the error caused by this method is relatively small.

[0027] Furthermore, for the control method of the control system for improving the accuracy of the belt scale under harsh working conditions described above, when first using the "voltage - flow" curve, the initial output maximum flow signal is taken for the output result to make the main belt enter the high - speed mode. Then, through subsequent learning cycles, the correct output result can be quickly found, and the correct value is output to make the main belt enter the correct control process.

[0028] The beneficial effects of the present invention are as follows: The front - end belt scale at the tunneling point of the present invention adopts a single - point suspended weighing unit in an array belt scale, and the subsequent main belt scale adopts an array belt scale. Then, according to the learning and calibration function of the "voltage - flow" curve of this system, the measurement accuracy of the front - end simple belt scale can reach a weighing accuracy of less than 0.5%; Using this set of solutions can effectively fill the gap in the accurate measurement problem in this type of occasion; It can effectively solve the problem of accurate weighing of the belt scale under harsh working conditions, subverting the traditional mode that the belt scale only relies on a single machine to complete weighing for a long time, achieving a new breakthrough in the intelligent weighing of the belt scale, and this principle can be applied to more similar occasions to improve the overall weighing technology level of the belt scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the system of the present invention.

[0030] Figure 2 It is a block diagram of the working principle of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Example 1

[0032] This example provides a control system for improving the accuracy of the belt scale under harsh working conditions, and the structure is asFigure 1 and Figure 2 As shown in Figure 2 , it includes a heading point belt scale J, an intermediate conveying belt 2, a main belt scale Z, and a central controller; the heading point belt scale adopts a single-point suspended weighing unit in an array belt scale, and the main belt scale adopts an array belt scale; the heading conveying belt 1 is connected to the main conveying belt 3 through the intermediate conveying belt 2; the heading point belt scale is installed on the heading conveying belt 1 at the heading point, and nearby collects the weight signal of the conveyed material, and transmits the signal and the corresponding speed signal to the central controller together; the main belt scale is installed on the main conveying belt 3 following the heading conveying belt, accurately collects the weight of the conveyed material, and transmits the accurate flow signal and the corresponding speed signal to the central controller together; the central controller is an independent computer, which collects the weight, flow, and speed signals sent by the heading point belt scale and the main belt scale, and calculates according to the learning model in the central controller to obtain the corrected flow signal of the heading point belt scale, and sends it to the upper-level control computer to achieve the output of the accurate flow value of the heading point belt scale immediately.

[0033] The control method of the control system for improving the accuracy of the belt scale under harsh working conditions in this embodiment includes the following steps:

[0034] ⑴ Install a heading point belt scale on the belt at the heading point, and the heading point belt scale detects the weight signal voltage at the moment when the material passes through.

[0035] ⑵ A "voltage - flow" curve is preset in the heading point belt scale. According to the weight signal voltage detected by the heading point belt scale, the corresponding flow value can be directly obtained by searching and matching the curve, and the matched flow value is sent to the central controller for frequency conversion control of the main belt.

[0036] ⑶ The weight signal voltage at the moment when the material passes through detected by the heading point belt scale is simultaneously pushed into the system stack of the central controller.

[0037] ⑷ The material at the aforementioned moment passes through the conveying belt and enters the main belt scale after a period of delay, and the accurate weight and the corresponding flow value at this moment can be obtained. At this time, find out the weight signal voltage value corresponding to the moment detected by the heading point belt scale from the system stack for comparison, and the correct "voltage - flow" ratio curve at the moment can be obtained.

[0038] ⑸ Correct the preset "voltage - flow" curve existing in the heading point belt scale, and re-inject the corrected "voltage - flow" curve into the heading point belt scale.

[0039] ⑹ Through the detection and correction at different points, the preset "voltage - flow" curve in the heading point belt scale can be continuously corrected, thereby realizing the learning cycle of the system.

[0040] When the "voltage - flow" curve in this embodiment is initially established and there is only one instantaneous point on the curve, the other points on the curve can all use the same value as the initial value; when the "voltage - flow" curve is used for the first time, the initial output is the maximum flow signal for the output result, so that the main belt enters the high - speed mode, and then through subsequent learning cycles, the correct output result can be quickly found, and then the correct value is output to make the main belt enter the correct control process.

[0041] When this embodiment is in use, a tunneling - point belt scale J is installed on the belt conveyor near the coal - mining tunneling point to obtain the weight signal of the tunneling coal in a timely manner. The main conveyor belt is installed at the rear of the tunneling conveyor belt and the middle - transport belt process at the tunneling point. At a suitable position on the main conveyor belt, a high - precision main belt scale Z is installed; since the main conveyor belt is a large - scale belt with good structure and good working conditions, high - accuracy metering of the belt scale can be achieved.

[0042] A "voltage - flow" curve is preset in the tunneling - point belt scale J, that is, according to the weight - signal voltage detected by the belt scale, the corresponding flow value can be directly obtained by looking up the curve. When the coal at point A (the section of coal on the tunneling - point belt scale J at a certain moment) that we are studying passes through the tunneling - point belt scale J, the tunneling - point belt scale J detects the weight - signal voltage and looks up the stored "voltage - flow" curve to obtain the flow value at this time, and sends this flow value to the underground central control computer for frequency - conversion control of the main belt. At the same time, the weight - signal voltage value of point A is pushed into the system stack. Since the tunneling - point belt scale J is a simple belt scale with poor working conditions and low metering accuracy, the flow data of point A may not be accurate.

[0043] When the material at point A passes through the conveyor belt and enters the main belt scale Z after a period of delay, the accurate weight and corresponding flow value of point A can be obtained. At this time, the corresponding weight - signal voltage value of point A is taken out of the stack for comparison, and the correct "voltage - flow" ratio of point A can be obtained, that is, a point on the "voltage - flow" curve, which is called the "slope" in the weighing model. After obtaining the "slope" of this point, the value of this point is used to correct the "voltage - flow" curve stored in the tunneling - point belt scale J to form a new curve. The above process is expressed by the following formula:

[0044] Zaq / Jav = Ja (slope) Formula 1

[0045] Where: Zaq—the flow value corresponding to point A of the main belt scale, t / h,

[0046] Jav—the weight - signal voltage value corresponding to point A of the tunneling - point belt scale, V,

[0047] Ja — weighing slope t / hv corresponding to the weight signal voltage value at point A.

[0048] In the belt scale J at the tunneling point, when it is detected that there is material passing through, the material flow value Jxq at this time is calculated using the following formula and sent to the central computer for main belt speed control.

[0049] Jxv × Jx = Jxq Formula 2

[0050] Where: Jxv — weight signal voltage value at point x detected by the belt scale,

[0051] Jx — slope value corresponding to point x in the "voltage - flow" curve,

[0052] Jxq — flow value at point x on the belt scale.

[0053] The above content describes the comparison and correction process between the front - end detection (tunneling point belt scale measurement) and the back - end detection (main belt scale measurement) at point A (x), as well as the process of calculating the flow rate when the tunneling point belt scale J is working normally. By detecting and correcting different points, the curve originally stored in the tunneling point belt scale J can be continuously corrected, thus realizing the learning cycle of the system.

[0054] In addition to the above - mentioned embodiments, the present invention may also have other implementation manners. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. Control method of a control system for improving the accuracy of belt scales under harsh working conditions, characterized in that it includes the following steps: ⑴ Install a heading point belt scale on the belt at the heading point, and the heading point belt scale detects the weight signal voltage at the moment when the material passes through; ⑵ A "voltage - flow" curve is preset in the heading point belt scale. According to the weight signal voltage detected by the heading point belt scale, the corresponding flow value can be directly obtained by looking up the curve match, and the matched flow value is sent to the central controller for frequency conversion control of the main belt; ⑶ The weight signal voltage detected by the heading point belt scale at the moment when the material passes through is simultaneously pushed into the system stack of the central controller; ⑷ The material at the aforementioned moment passes through the conveyor belt and enters the main belt scale after a period of delay, and the accurate weight and corresponding flow value at this moment can be obtained. At this time, the weight signal voltage value corresponding to the detected moment at the heading point belt scale is found from the system stack for comparison, and the correct "voltage - flow" ratio curve at the moment can be obtained; ⑸ Correct the preset "voltage - flow" curve existing in the heading point belt scale, and re - inject the corrected "voltage - flow" curve into the heading point belt scale; ⑹ Through detection and correction at different points, the preset "voltage - flow" curve in the heading point belt scale can be continuously corrected, thus realizing the learning cycle of the system; The control system for the accuracy of the belt scale includes a heading point belt scale, a main belt scale, and a central controller; The heading point belt scale is installed on the heading conveyor belt at the heading point, proximally collects the weight signal of the conveyed material, and transmits this signal and the corresponding speed signal to the central controller together; The main belt scale is installed on the main conveyor belt following the heading conveyor belt, accurately collects the weight of the conveyed material, and transmits the accurate flow signal and the corresponding speed signal to the central controller together; The central controller is an independent computer or its function is integrated into the instrument of the belt scale, collects the weight, flow, and speed signals sent by the heading point belt scale and the main belt scale, and calculates according to the learning model in the central controller to obtain the corrected flow signal of the heading point belt scale, and sends it to the superior control computer to realize the output of the accurate flow value of the heading point belt scale in real - time.

2. The control method of the control system for improving the accuracy of belt scales under harsh working conditions as described in claim 1, characterized in that: The heading point belt scale adopts a single - point suspended weighing unit in an array belt scale.

3. The control method of the control system for improving the accuracy of belt scales under harsh working conditions as described in claim 1, characterized in that: The main belt scale adopts an array belt scale.

4. The control method of the control system for improving the accuracy of belt scales under harsh working conditions as described in claim 1, characterized in that: When initially establishing the "voltage - flow" curve and there is only one moment point on the curve, the other points on the curve can all adopt the same value as the initial value.

5. The control method of the control system for improving the accuracy of belt scales under harsh working conditions as described in claim 4, characterized in that: When the "voltage - flow" curve is used for the first time, the initial output result is to output the maximum flow signal, so that the main belt enters the high - speed mode. Then, through subsequent learning cycles, the correct output result can be quickly found, and the correct value is output to make the main belt enter the correct control process.

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