CN-122018418-A - PLC control method and system for mineral separation ore pulp stabilization

Abstract

The invention discloses a PLC control method and system for stably controlling flow of mineral separation pulp, and relates to the technical field of gravity mineral separation. The control system mainly comprises an upper computer DCS, a PLC controller, a touch screen, a flowmeter, a concentration meter and an execution assembly. The control method mainly comprises the steps of obtaining ore pulp flow data of each pipeline through a detection element, carrying out filtering treatment on the ore pulp flow data by adopting a dynamic median-arithmetic average filtering fusion method, wherein a dynamic weight coefficient alpha is calculated according to a formula alpha=sigma/(sigma+|Deltax|+epsilon) so as to eliminate the influence of pulse flow noise on collected data during ore feeding, inputting the filtered flow data as a feedback signal into a pulse suppression PID controller, and automatically adjusting the opening of an execution assembly by adopting a control strategy of combining incomplete differentiation, differential advance and integral separation. The invention obviously improves the anti-interference capability of the PLC control system to noise, and has the advantages of high precision, quick response, strong stability and the like for controlling the flow of ore pulp such as ore feeding of gravity ore dressing such as spiral ore dressing.

Inventors

• LIU HUIZHONG
• HU KAI
• FENG ZHIWEN
• Zou Qihua
• HUANG JIAYING
• Li Zichaoxi
• HUANG LIXIN
• ZHAO YUXUAN
• Zuo Yifeng
• ZHAO KEJIA
• HUANG JIAXIN

Assignees

• 江西理工大学

Dates

Publication Date

20260512

Application Date

20251230

Claims (10)

1. 1. The PLC control method for stabilizing mineral separation pulp is characterized by comprising the following steps of: S1, acquiring pulp flow data of each pipeline through a detection element; S2, filtering the pulp flow data by adopting a dynamic median-arithmetic average filtering fusion method to reduce the influence of pulse ore feeding and random noise, wherein the dynamic median-arithmetic average filtering can be described as: Wherein alpha represents a dynamic weight coefficient and is used for controlling the mixing proportion of median filtering and mean filtering, and alpha is E [0,1]; x n represents the analog input value at the nth sampling time; Median (x n ) represents the Median of the analog input values; N represents N sample values; x n-i represents the historical time sample value; The dynamic weight coefficient alpha dynamic adjustment can be described as: Wherein sigma is expressed as standard deviation; The delta x represents the last two samples difference; epsilon is a constant that prevents the denominator from being zero; S3, inputting the filtered flow data as a feedback signal into a pulse suppression PID controller, wherein the pulse suppression PID controller adopts a control strategy of combining incomplete differentiation, differential advance and integral separation, and outputs a control signal to adjust the opening of an execution assembly.
2. 2. The PLC control method for mineral separation pulp stabilization according to claim 1, wherein the pulse suppression PID controller employs incomplete differentiation, introduces a low pass filter in a differentiation term to reduce the influence of high frequency noise, employs differential advance to differentiate only a measured value, avoids the set value mutation from causing oscillation of the differentiation term, employs integral separation, stops integration when an error is excessive, prevents integral saturation, and the pulse suppression PID expression can be described as: wherein K p ,K i ,K d represents proportional, integral and differential gains; e k denotes the error of the kth sample; T s denotes a sampling period; PV k represents the kth measurement; t f denotes the filter time constant of the incomplete differentiation.
3. 3. The PLC control method for mineral separation pulp stabilization according to claim 2, wherein the sampling error and integral separation logic expression can be described as: sampling error: e k ＝r k -PV k Integral separation logic: wherein r k represents a set value and ε represents an integral separation threshold.
4. 4. The PLC control method for mineral separation pulp stabilization according to claim 2, wherein the derivative term is used to implement first order low pass filtering based only on the measured rate of change PV k -PV k-1 ,T f +T s , suppressing noise.
5. 5. The PLC control method for stabilizing mineral separation pulp according to claim 1, further comprising a manual control mode, wherein in the manual control mode, a control quantity corresponding to a 4-20 mA current signal is input through a touch screen or an upper computer DCS, and the opening degree of an execution assembly is directly controlled.
6. 6. The PLC control method of mineral separation pulp stabilization according to claim 1, wherein the detection element comprises a pulp electromagnetic flowmeter and a pulp concentration meter, and the actuator assembly comprises a linear motion cylinder, a positioner, a valve stem, and a valve cartridge.
7. 7. The method for controlling the ore dressing pulp to be stabilized according to claim 1, wherein the PLC controller and the upper computer DCS are communicated by adopting a Modbus RTU protocol, and the PLC controller and the touch screen are communicated by adopting an Ethernet/IP protocol.
8. 8. The PLC control method for mineral separation pulp stabilization according to claim 1, wherein the constant epsilon is 0.001.
9. 9. A PLC control system for mineral separation pulp stabilization, characterized in that the system is adapted to implement a mineral separation pulp stabilization control method according to any one of claims 1-8, comprising: The device comprises an upper computer, a PLC controller, a detection element, a man-machine interaction interface and an execution assembly, wherein the detection element is connected with the input end of the PLC controller, the execution assembly is connected with the output end of the PLC controller, and the PLC controller is in bidirectional communication connection with the upper computer.
10. 10. The PLC control system for mineral separation pulp stabilization according to claim 9, wherein the detection element comprises a pulp electromagnetic flowmeter for detecting pulp flow of each pipeline in real time, the detection element further comprises a pulp concentration meter for detecting pulp concentration in the mineral separation tank in real time, and the execution assembly comprises a valve composed of a linear motion cylinder, a positioner, a valve rod and a valve core.

Description

PLC control method and system for mineral separation ore pulp stabilization Technical Field The invention relates to the field of gravity mineral separation, in particular to a PLC control method and a system for stably controlling flow of gravity mineral separation ore pulp. Background In the gravity mineral separation field, no matter the spiral mineral separation machine is used for mineral separation or the shaking table mineral separation, the control requirement on the flow of ore pulp for mineral feeding is higher, and the unstable ore feeding, the overlarge flow or the overlarge flow have great influence on the mineral separation effect. In actual mineral separation production, the primary mineral separation system usually corresponds to a multi-path secondary mineral separation system, the mineral inflow of the primary mineral separation system is not constant, part of secondary mineral separation branches are selectively opened or closed according to the mineral inflow of the primary mineral separation system and the optimal treatment capacity of the separation equipment, and the pipe inflow of the secondary mineral separation system needs to be adjusted to achieve the optimal separation effect. Therefore, how to make the primary ore separation system feed ore stably and dynamically distribute the flow of ore pulp to the secondary ore separation system is a problem to be solved in the gravity ore separation field. The existing PLC control system has the following technical problems that on one hand, pulse flow noise is generated due to pulse ore feeding, the influence of the pulse noise on flow detection signals is difficult to effectively eliminate by a traditional filtering method, and on the other hand, problems of integral saturation, differential term oscillation and the like are easy to generate when the traditional PID controller is in interference with the pulse noise, so that control accuracy is reduced, and system response is slow. Disclosure of Invention The invention aims to provide a PLC control method and a system for stably controlling the flow of mineral separation pulp, so as to ensure that a primary mineral separation system in gravity mineral separation is stable in mineral feeding and dynamic distribution of mineral feeding flow of a secondary mineral separation system. In a first aspect, the invention provides a PLC control method for stably controlling the flow of mineral separation pulp, which adopts the following technical scheme: the PLC control method for stabilizing mineral separation pulp is characterized by comprising the following steps of: S1, acquiring pulp flow data of each pipeline through a detection element; S2, filtering the pulp flow data by adopting a dynamic median-arithmetic average filtering fusion method to reduce the influence of pulse ore feeding and random noise, wherein the dynamic median-arithmetic average filtering can be described as: Wherein alpha represents a dynamic weight coefficient and is used for controlling the mixing proportion of median filtering and mean filtering, and alpha is E [0,1]; x n represents the analog input value at the nth sampling time; Median (x n) represents the Median of the analog input values; N represents N sample values; x n-i represents the historical time sample value; The dynamic weight coefficient alpha dynamic adjustment can be described as: Wherein sigma is expressed as standard deviation; The delta x represents the last two samples difference; epsilon is a constant that prevents the denominator from being zero; S3, inputting the filtered flow data as a feedback signal into a pulse suppression PID controller, wherein the pulse suppression PID controller adopts a control strategy of combining incomplete differentiation, differential advance and integral separation, and outputs a control signal to adjust the opening of an execution assembly. Further, the pulse suppression PID controller adopts incomplete differentiation, introduces a low-pass filter in a differentiation term to reduce the influence of high-frequency noise, adopts differential advance to differentiate only measured values to avoid oscillation of the differentiation term caused by abrupt change of a set value, adopts integral separation to stop integration when the error is overlarge to prevent integral saturation, and can be described as: wherein K p,Ki,Kd represents proportional, integral and differential gains; e k denotes the error of the kth sample; T s denotes a sampling period; PV k represents the kth measurement; t f denotes the filter time constant of the incomplete differentiation. Further, the sampling error, integral separation logic expressions can be described as: sampling error: ek＝rk-PVk Integral separation logic: wherein r k represents a set value and ε represents an integral separation threshold. Further, the derivative term is used to implement first order low pass filtering based only on the measured rate of change PV k-PVk-1,Tf+