Intelligent control method and system for screening machine

Abstract

The invention relates to the field of intelligent control, in particular to an intelligent control method and system for a screening machine, and the method comprises the steps: respectively collecting the current and voltage of a motor in a set work period, and the oscillation frequency and oscillation amplitude of the screening machine in the set work period; calculating the blocking degree of a screen in the screening machine; wherein the first anomaly in the blocking degree is directly proportional to the current and the voltage, and the second anomaly is inversely proportional to the oscillation frequency and is directly proportional to the oscillation amplitude; obtaining an error signal; the error signal is input into a PID controller, and a control signal is output; the working state of the screening machine is adjusted through the control signal. By comprehensively considering the blocking degree of the screen, the PID controller can output more appropriate control signals, unnecessary motor starting and stopping and large-amplitude adjustment of oscillation frequency and amplitude are avoided, and therefore the screening efficiency and quality of the screening machine are improved.

Description

Technical Field

[0001] The present invention relates to the field of intelligent control and to an intelligent control method and system for a screening machine. Background Art

[0002] Vacuum melting inert gas protection atomization system is often used to produce various alloy powder materials. Among them, small metal droplets will be generated after atomization, and these small droplets will quickly cool in the inert gas to form alloy powder. After that, these alloy powders are passed through a screening machine to screen and grade the alloy powders. The screening machine is usually composed of multiple screens, each with a different aperture, so that alloy powders of different particle sizes can be separated.

[0003] At present, a patent application document with publication number CN117284799A discloses a method for guiding the optimization of coal blending for an automatic coal blending machine for a silo, including: determining the initial feeding uniformity of the feeder by determining the adjustment range of the frequency converter; adjusting the screening speed of the screening machine to determine the initial screening efficiency of the screening machine; if the initial screening efficiency is lower than a preset threshold, increasing the feeding speed by adjusting the motor operating frequency of the feeder frequency converter to improve the screening efficiency; determining the first screening efficiency according to the new feeding speed; if the first screening efficiency is still lower than the preset threshold, adjusting the initial feeding uniformity according to the performance level of the feeder to obtain the first feeding uniformity; determining the second screening efficiency according to the adjusted feeding uniformity; when the second screening efficiency reaches the preset threshold, operating the unit and performing screening and blending.

[0004] The above method solves the problem of poor coal blending accuracy during the automatic coal blending process of the automatic coal blending machine due to the difficulty in controlling and adjusting the source and proportion of the coal types. However, in the process of adjusting the feeding speed to improve the screening efficiency, there may be risks such as screen clogging. The screening machine needs a certain amount of time to return to normal working condition, which reduces the screening efficiency and quality. Summary of the invention

[0005] In order to solve the technical problem that the above-mentioned screening machine operates abnormally and reduces the screening efficiency and quality, the present invention provides solutions in the following aspects.

[0006] In a first aspect, a screening machine intelligent control method comprises: The current and voltage within the set working cycle of the motor, and the oscillation frequency and oscillation amplitude within the set working cycle of the screening machine are collected respectively; Calculate the degree of blockage of the screen in the screening machine; the degree of blockage is: ; In the formula, is the degree of blockage, is the first abnormality degree, is the second abnormality, Indicates normalization processing; the first abnormality is proportional to both the current and the voltage, and the second abnormality is inversely proportional to the oscillation frequency and proportional to the oscillation amplitude respectively; Get error signal, error signal for: ; In the formula, is the degree of blockage, is the ideal oscillation frequency, To set the average oscillation frequency within the working cycle, is the ideal oscillation amplitude, is the average oscillation amplitude within the set working cycle; The error signal is input into the PID controller, and the control signal is output; the control signal is used to adjust the working state of the screening machine.

[0007] The present invention analyzes the collected data, calculates the blockage degree of a screen, and introduces the blockage degree into the error signal, so that the error signal can more accurately reflect the actual working state of the screening machine, so as to avoid over-adjustment of the PID controller caused by fluctuations in the error signal, so that the PID controller can output a more appropriate control signal, and unnecessary motor start and stop and large-scale adjustment of the oscillation frequency and amplitude can be avoided, which not only improves the response speed of the control system, but also improves the control accuracy, thereby improving the screening efficiency and quality of the screening machine.

[0008] Preferably, the output control signal further includes: Gradually increase the initial proportional gain of the PID controller. When the output of the PID controller shows periodic fluctuations, record the proportional gain value at this time as the critical gain. Set the parameters and multiply the parameters by the critical gain as the proportional gain of the PID controller.

[0009] By gradually increasing the proportional gain until the system begins to oscillate continuously, the maximum gain that the system can withstand, that is, the critical gain, can be accurately found. This ensures that the largest possible gain is used while maintaining system stability, thereby improving the system's response speed and control accuracy.

[0010] Preferably, the control signal is: ; In the formula, is the control signal, is the error signal, is the proportional gain, is the integral gain, is the differential gain.

[0011] Preferably, the process of obtaining the first abnormality degree includes: Taking any moment as the center point, intercept the current and voltage values ​​corresponding to a set number of moments before and after the center point, sort the current and voltage values ​​in the order of the moments to obtain a data point sequence, and construct a target sequence; calculate the average value of the sum of the first difference and the second difference of all target moments, and use the average value as the first abnormality; The first difference is the sum of the absolute value of the first difference and the absolute value of the second difference; the absolute value of the first difference is the absolute value of the difference between the current at the target moment and the average current, and the absolute value of the second difference is the absolute value of the difference between the voltage at the target moment and the average voltage; the second difference is the sum of the first distance average value and the second distance average value; the first distance average value is the average value of the Euclidean distance between the current of the target sequence and the ideal current, and the second distance average value is the average value of the Euclidean distance between the voltage of the target sequence and the ideal voltage.

[0012] By selecting data near the target moment as the target sequence, the time-varying characteristics of current and voltage can be taken into account, thereby more accurately reflecting the real-time status of the system. By calculating the average value of the sum of the first difference and the second difference, it is possible to respond to small changes in current and voltage in a timely manner, thereby improving the response speed and sensitivity of abnormality detection.

[0013] Preferably, the process of obtaining the second abnormality degree includes: Calculate the sum of the third difference and the fourth difference of all target moments, and take the third quartile of the sum of all the third differences and the fourth differences as the second abnormality; wherein the ratio of the oscillation amplitude at the target time to the maximum oscillation amplitude is calculated, the reciprocal of the difference between the oscillation frequency at the target time and the minimum oscillation frequency is calculated, and the product of the ratio and the reciprocal is taken as the third difference; The absolute value of the difference between the oscillation frequency at the target time and the ideal oscillation frequency, and the absolute value of the difference between the oscillation amplitude and the ideal oscillation amplitude are calculated respectively, and the two absolute values ​​of the difference are taken as the fourth difference.

[0014] By comprehensively considering multiple parameters such as oscillation amplitude, oscillation frequency, current and voltage, the calculation method of the second abnormality can more comprehensively reflect the operating status of the screening machine; the third quartile is located in the upper half of the data set and has a higher sensitivity to larger outliers.

[0015] Preferably, the process of obtaining the first abnormality degree includes: ; In the formula, is the first abnormality degree, , are the current and voltage weight coefficients respectively, For the The current at the moment, For the The voltage at the moment, is the average current at all times, is the average voltage at all times, is the total number of all moments.

[0016] Preferably, the process of obtaining the second abnormality degree includes: ; In the formula, is the second abnormality, , are the weight coefficients of oscillation amplitude and oscillation frequency respectively, For the The oscillation amplitude at time, For the The oscillation frequency at the moment, is the ideal oscillation amplitude, is the ideal oscillation frequency, is the total number of all moments.

[0017] By introducing weight coefficients of current, voltage, oscillation amplitude and oscillation frequency, the relative importance of current, voltage, oscillation amplitude and oscillation frequency in the calculation of abnormality can be adjusted according to the actual application scenario.

[0018] In a second aspect, an intelligent control system for a screening machine includes: a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the above-mentioned intelligent control method for the screening machine is implemented.

[0019] Beneficial effects: The present invention calculates the blockage degree of the screen by analyzing the current, voltage, oscillation frequency and oscillation amplitude, and introduces the blockage degree into the error signal. The blockage condition of the drying net can be monitored in real time, and the PID controller is used to automatically adjust the working state of the screening machine according to the error signal, which not only improves the response speed of the control system, but also improves the control accuracy, thereby improving the screening efficiency and quality of the screening machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein: Figure 1 It is a method flow chart of steps S1 to S4 in an intelligent control method for a screening machine according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0022] The embodiment of the present invention discloses an intelligent control method for a screening machine, referring to Figure 1 , including steps S1 to S4, which are specifically as follows: S1: respectively collect the current and voltage of the motor within the set working cycle, and the oscillation frequency and oscillation amplitude of the screening machine within the set working cycle.

[0023] The blockage of the screen has a significant impact on the current and voltage of the motor in the screening machine. When the screen is blocked, the screening machine needs more energy to maintain vibration, which will increase the load of the motor, so it is necessary to obtain the current and voltage data of the motor. In addition, the blockage of the screen will increase the resistance of the material passing through the screen hole. At this time, additional energy is required to overcome the blockage, which will lead to a decrease in the vibration frequency of the screening machine and an increase in the vibration amplitude. Therefore, it is necessary to obtain the vibration frequency and vibration amplitude of the screening machine.

[0024] Specifically, current and voltage sensors are installed in the power supply line of the motor to collect the current and voltage in the working cycle (in the embodiment of the present invention, the working cycle is set to T = 30 minutes, and in other embodiments, the working cycle can be set according to historical data or experience), and a vibration sensor is installed at the bottom of the screen of the screening machine to collect the vibration frequency and vibration amplitude in the same working cycle. Use filtering technology (such as low-pass, high-pass, band-pass or band-stop filter) to remove the noise components in the above-obtained data, use the average interpolation method to supplement the blank data in the data, and use the maximum and minimum normalization algorithm to normalize the data, and standardize the current and voltage to between 0 and 1.

[0025] The ideal current and ideal voltage of the motor are obtained according to the factory nameplate of the motor, and the ideal oscillation frequency and ideal oscillation amplitude of the screening machine are obtained according to the manufacturer of the screening machine.

[0026] Among them, filtering technology, average interpolation method, and maximum and minimum normalization algorithm are all existing algorithms and will not be described in detail here.

[0027] S2: Calculate the degree of blockage of the screen in the screening machine.

[0028] First, taking any moment as the center point, intercept the current and voltage values ​​corresponding to a set number of moments before and after the center point, sort the current and voltage values ​​in order of the moments to obtain a data point sequence, and construct a target sequence; calculate the average value of the sum of the first difference and the second difference of all target moments, and use the average value as the first abnormality; the first difference is the sum of the absolute value of the first difference and the absolute value of the second difference; the absolute value of the first difference is the absolute value of the difference between the current at the target moment and the average current, and the absolute value of the second difference is the absolute value of the difference between the voltage at the target moment and the average voltage; the second difference is the sum of the first distance average value and the second distance average value; the first distance average value is the average value of the Euclidean distance between the current of the target sequence and the ideal current, and the second distance average value is the average value of the Euclidean distance between the voltage of the target sequence and the ideal voltage.

[0029] Then the target sequence is expressed as: {( , , ), , , ), ( , , )}.

[0030] For example, The time is the target time for analysis and the calculation of the The absolute value of the difference between the current at the moment and the average current at all moments is taken as the first absolute value of the difference; similarly, the second The absolute value of the difference between the voltage at the moment and the average voltage at all moments is taken as the second absolute value of the difference. The sum of the first absolute value of the difference and the second absolute value of the difference is taken as the first difference.

[0031] The above The first difference of the moments satisfies the relationship:

[0032] In the formula, For the The first difference of moment, For the The current at the moment, For the The voltage at the moment, is the average current at all times, is the average voltage at all times.

[0033] Take a moment to the left and right and mark them as Time, time, then Time, Time, The time constitutes a target sequence. The Euclidean distance between the current corresponding to each moment in the target sequence and the ideal current is calculated, and the average value is taken as the first distance average value. Similarly, the Euclidean distance between the voltage corresponding to each moment in the target sequence and the ideal voltage is obtained, and the average value is taken as the second distance average value.

[0034] The above The second difference of the moments satisfies the relationship:

[0035] In the formula, For the The second difference of moments, , The target sequence is The current and voltage corresponding to each moment.

[0036] Similarly, the first difference and second difference at all moments can be obtained.

[0037] Then the above first abnormality degree satisfies the relationship:

[0038] In the formula, is the first abnormality degree.

[0039] In other embodiments, the first abnormality degree further satisfies the following relationship:

[0040] In the formula, is the first abnormality degree, , are the current and voltage weight coefficients respectively, For the The current at the moment, For the The voltage at the moment, is the average current at all times, is the average voltage at all times, is the total number of all moments.

[0041] Secondly, the sum of the third difference and the fourth difference of all target moments is calculated, and the third quartile of the sum of all the third differences and the fourth differences is used as the second abnormality. Among them, the ratio of the oscillation amplitude at the target moment to the maximum oscillation amplitude is calculated, and the inverse of the difference between the oscillation frequency at the target moment and the minimum oscillation frequency is calculated, and the product of the ratio and the inverse is used as the third difference; the absolute value of the difference between the oscillation frequency at the target moment and the ideal oscillation frequency, and the absolute value of the difference between the oscillation amplitude and the ideal oscillation amplitude are calculated respectively, and the two absolute values ​​of the difference are used as the fourth difference.

[0042] Exemplarily, the third difference satisfies the relationship:

[0043] In the formula, For the The third difference of moments, For the The oscillation amplitude at time, For the The oscillation frequency at the moment, is the maximum oscillation amplitude, is the minimum oscillation frequency. If the oscillation amplitude decreases, it may indicate that the screen is clogged, because the clogging will reduce the vibration capacity of the screening machine. The oscillation frequency at the moment deviates significantly from the minimum oscillation frequency, which also affects the vibration effect of the screen and further affects the degree of blockage.

[0044] The fourth difference satisfies the relationship:

[0045] In the formula, For the The fourth difference of moments, For the The oscillation amplitude at time, For the The oscillation frequency at the moment, is the ideal oscillation amplitude, is the ideal oscillation frequency.

[0046] Similarly, the third and fourth differences of all moments can be obtained. The third quartile of the sum of all third and fourth differences is taken as the second abnormality and marked as Using the third quartile reduces the impact of outliers and provides a more robust measure to assess the degree of congestion.

[0047] It should be noted that after the sum of the first difference and the second difference is calculated, a normalization process may be performed, and the same operation may be performed on the third difference and the fourth difference.

[0048] In other embodiments, the second abnormality degree also satisfies the relationship:

[0049] In the formula, is the second abnormality, , are the weight coefficients of oscillation amplitude and oscillation frequency respectively, For the The oscillation amplitude at time, For the The oscillation frequency at the moment, is the ideal oscillation amplitude, is the ideal oscillation frequency, is the total number of all moments. , Can be set based on experience.

[0050] After the first abnormality and the second abnormality are obtained through the above operation, the blockage degree of the screen can be calculated. The blockage degree satisfies the following relationship:

[0051] In the formula, is the degree of blockage, is the first abnormality degree, is the second abnormality, Indicates normalization processing.

[0052] S3: Obtain error signal.

[0053] The error signal is the difference between the actual value and the target value. In the embodiment of the present invention, the working cycle is set by calculating The average oscillation frequency and the average oscillation amplitude in the screen are calculated, and then the difference between the average vibration frequency and the ideal vibration frequency, and the difference between the average vibration amplitude and the ideal vibration amplitude are calculated, and the total error signal is obtained according to the blockage degree of the screen calculated in the above step S2. The error signal satisfies the relationship:

[0054] In the formula, is the degree of blockage, is the ideal oscillation frequency, To set the average oscillation frequency within the working cycle, is the ideal oscillation amplitude, is the average oscillation amplitude within the set working cycle.

[0055] Among them, as the blockage degree increases, the error signal also increases, and vice versa.

[0056] S4: Input the error signal into the PID controller and output the control signal; use the control signal to adjust the working state of the screening machine.

[0057] The obtained error signal is input into the PID controller, and the PID controller calculates a control signal according to the error signal, and uses the control signal to adjust the vibration frequency and / or vibration amplitude of the screening machine to reduce the error and restore the screening machine to an ideal working state.

[0058] Among them, the control signal satisfies the relationship:

[0059] In the formula, is the control signal, is the error signal, is the proportional gain, is the integral gain, is the differential gain.

[0060] It should be noted that after obtaining the control signal, the PID controller parameters can also be adjusted and optimized to improve the control progress and response speed.

[0061] Exemplarily, the initial proportional gain of the PID controller is gradually increased, and when the output of the PID controller shows periodic fluctuations, the proportional gain value at this time is recorded as the critical gain; the parameter is set, and the product of the parameter and the critical gain is used as the proportional gain of the PID controller. The exemplary setting parameter is 0.65.

[0062] The present invention analyzes the collected data, calculates the blockage degree of a screen, and introduces the blockage degree into the error signal, so that the error signal can more accurately reflect the actual working state of the screening machine, so as to avoid over-adjustment of the PID controller caused by fluctuations in the error signal, so that the PID controller can output a more appropriate control signal, and unnecessary motor start and stop and large-scale adjustment of the oscillation frequency and amplitude can be avoided, which not only improves the response speed of the control system, but also improves the control accuracy.

[0063] The embodiment of the present invention further discloses an intelligent control system for a screening machine, including a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the intelligent control method for the screening machine according to the present invention is implemented.

[0064] The system also includes other components familiar to those skilled in the art, such as a communication bus and a communication interface. The configuration and functions of these components are known in the art and will not be described in detail here.

[0065] In the present invention, the aforementioned memory may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, apparatus or device. For example, a computer-readable storage medium may be any appropriate magnetic storage medium or magneto-optical storage medium, such as a resistive random access memory RRAM (Resistive Random Access Memory), a dynamic random access memory DRAM (Dynamic Random Access Memory), a static random access memory SRAM (Static Random-Access Memory), an enhanced dynamic random access memory EDRAM (Enhanced Dynamic Random Access Memory), a high-bandwidth memory HBM (High-Bandwidth Memory), a hybrid memory cube HMC (Hybrid Memory Cube), etc., or any other medium that can be used to store the required information and can be accessed by an application, a module or both. Any such computer storage medium may be part of a device or accessible or connectable to a device.

[0066] In the description of this specification, "plurality" or "several" means at least two, such as two, three or more, etc., unless otherwise clearly and specifically defined.

[0067] Although this specification has shown and described a number of embodiments of the present invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art will conceive of many modifications, changes and alternatives without departing from the ideas and spirit of the present invention. It should be understood that in the practice of the present invention, various alternatives to the embodiments of the present invention described herein may be employed.

Claims

1. An intelligent control method for a screening machine, characterized in that: include: The current and voltage within the set working cycle of the motor, and the oscillation frequency and oscillation amplitude within the set working cycle of the screening machine are collected respectively; Calculate the degree of blockage of the screen in the screening machine; the degree of blockage is: ; In the formula, is the degree of blockage, is the first abnormality degree, is the second abnormality, Indicates normalization processing; the first abnormality is proportional to both the current and the voltage, and the second abnormality is inversely proportional to the oscillation frequency and proportional to the oscillation amplitude respectively; Get error signal, error signal for: ; In the formula, is the degree of blockage, is the ideal oscillation frequency, To set the average oscillation frequency within the working cycle, is the ideal oscillation amplitude, is the average oscillation amplitude within the set working cycle; The error signal is input into the PID controller, and the control signal is output; the control signal is used to adjust the working state of the screening machine.

2. The intelligent control method for a screening machine according to claim 1, characterized in that: The output control signal also includes: Gradually increase the initial proportional gain of the PID controller. When the output of the PID controller shows periodic fluctuations, record the proportional gain value at this time as the critical gain. Set the parameters and multiply the parameters by the critical gain as the proportional gain of the PID controller.

3. The intelligent control method of a screening machine according to claim 2, characterized in that: The control signal is: ; In the formula, is the control signal, is the error signal, is the proportional gain, is the integral gain, is the differential gain.

4. The intelligent control method for a screening machine according to claim 3, characterized in that: The process of obtaining the first abnormality degree includes: Taking any moment as the center point, intercept the current and voltage values ​​corresponding to a set number of moments before and after the center point, sort the current and voltage values ​​in order of the moments to obtain a data point sequence, and construct a target sequence; calculate the average value of the sum of the first difference and the second difference of all target moments, and use the average value as the first abnormality; the first difference is the sum of the absolute value of the first difference and the absolute value of the second difference; the absolute value of the first difference is the absolute value of the difference between the current at the target moment and the average current, and the absolute value of the second difference is the absolute value of the difference between the voltage at the target moment and the average voltage; the second difference is the sum of the first distance average value and the second distance average value; the first distance average value is the average value of the Euclidean distance between the current of the target sequence and the ideal current, and the second distance average value is the average value of the Euclidean distance between the voltage of the target sequence and the ideal voltage.

5. The intelligent control method for a screening machine according to claim 4, characterized in that: The process of obtaining the second abnormality degree includes: Calculate the sum of the third difference and the fourth difference of all target moments, and take the third quartile of the sum of all the third differences and the fourth differences as the second abnormality; wherein the ratio of the oscillation amplitude at the target time to the maximum oscillation amplitude is calculated, the reciprocal of the difference between the oscillation frequency at the target time and the minimum oscillation frequency is calculated, and the product of the ratio and the reciprocal is taken as the third difference; The absolute value of the difference between the oscillation frequency at the target time and the ideal oscillation frequency, and the absolute value of the difference between the oscillation amplitude and the ideal oscillation amplitude are calculated respectively, and the two absolute values ​​of the difference are taken as the fourth difference.

6. The intelligent control method for a screening machine according to claim 3, characterized in that: The process of obtaining the first abnormality degree includes: ; In the formula, is the first abnormality degree, , are the current and voltage weight coefficients respectively, For the The current at the moment, For the The voltage at the moment, is the average current at all times, is the average voltage at all times, is the total number of all moments.

7. The intelligent control method for a screening machine according to claim 6, characterized in that: The process of obtaining the second abnormality degree includes: ; In the formula, is the second abnormality, , are the weight coefficients of oscillation amplitude and oscillation frequency respectively, For the The oscillation amplitude at time, For the The oscillation frequency at the moment, is the ideal oscillation amplitude, is the ideal oscillation frequency, is the total number of all moments.

8. An intelligent control system for a screening machine, characterized in that: include: A processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the intelligent control method for the screening machine according to any one of claims 1 to 7 is implemented.

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