Time Delay Identification in Rare Earth Extraction Control
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Solution Overview
Problem
The rare earth extraction and separation process is plagued by significant time delays due to differences in stirring rates and times across extraction tanks, leading to inefficient control and increased waste, as existing models fail to accurately account for these delays, resulting in suboptimal product quality and resource utilization.
Innovation Solution
A method and system for identifying time delays by generating reference and comparison sequences based on rare earth element contents and process variables, preprocessing data, determining grey correlations, constructing time-correlation matrices, and using H∞ norms to quantify multi-time delays, allowing for precise control adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional extraction and separation process control is used without considering multi-time delay, then the control system is simple, but the regulation effect cannot act on the production process in real time, leading to large output overshoot and long regulation time
Solution Approach 1:
The patent applies preliminary action by identifying and compensating for time delays before they affect the control outcome. The method calculates time delay parameters for each extraction tank group and uses these pre-determined parameters to predict future states, allowing the control system to take advance corrective actions rather than reacting to delays after they occur.
Solution Approach 2:
The patent implements dynamics by transitioning from static control parameters to dynamic time-delay-compensated parameters. The control algorithm continuously updates predictions based on current process states and identified time delay characteristics, allowing the system to adapt its control actions in real-time to counteract the varying delays in different extraction tank groups.
2Ease of manufacture
If existing models substitute time delay as a constant, then the model is simple, but there is a certain gap between the established model and the actual rare earth extraction industry
Solution Approach 1:
The patent applies segmentation by dividing the extraction system into multiple independent tank groups, each with its own time delay characteristics. Instead of treating the entire system as a single unit with one constant delay, the method identifies and models the time delay for each segment separately, allowing for more accurate representation of the actual process while maintaining manageable model complexity.
Solution Approach 2:
The patent implements parameter changes by transforming the control approach from using fixed constant delay parameters to using dynamically identified time delay parameters. The method employs grey correlation analysis and H-infinity norm optimization to continuously determine accurate time delay parameters for each tank group, significantly improving model accuracy compared to constant substitution while maintaining reasonable computational complexity.
3Productivity
If multi-time delay is not compensated, then the control algorithm is simple, but the system output cannot reflect the changes of the system input set value and control signal in time, reducing productivity
Solution Approach 1:
The patent implements feedback by using the identified time delay parameters to create a predictive control loop. The system continuously monitors process outputs, compares them with predicted values based on time-delay-compensated models, and adjusts control inputs accordingly. This feedback mechanism allows the system to compensate for delays in real-time, significantly improving response speed and regulation performance.
Solution Approach 2:
The patent applies preliminary action by calculating and storing time delay parameters for each extraction tank group in advance, before actual control operations. This pre-characterization of delay parameters allows the control algorithm to quickly compensate for delays during operation without complex real-time calculations, improving both response speed and computational efficiency.
Data Source
AI summary
A method and system for identifying a time delay in an extraction and separation process of rare earth: a reference sequence and comparison sequences are generated based on component contents of multiple rare earth elements and multiple process variables, and then preprocessed to determine a grey correlation. A comparison sequence with a highest correlation with the reference sequence is determined. An original data matrix is formed by taking the comparison sequence as a process variable. A time-correlation data matrix is constructed based on the obtained time delay sequence, time base sequence, and original data matrix to generate a time-correlation analysis matrix. A matrix H∞ norm is used to quantitatively describe the characteristics of the time-correlation analysis matrix, so as to determine a time delay sequence corresponding to a maximum H∞ norm as a to-be-solved multi-time delay.