Process Control Linearization via Automatic Correction Values
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Solution Overview
Problem
Existing closed-loop control systems in process engineering often suffer from reduced control accuracy due to nonlinear operating characteristics, which are inadequately addressed by conventional linearization methods, and can be further compromised by incorrectly dimensioned process valves.
Innovation Solution
A method and device for closed-loop or open-loop process control that automatically determines and applies correction characteristics to linearize the process by generating corrected position set values using a tuning stage, position sensor, and process sensor, thereby compensating for nonlinearities directly on the process controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a linear PID-process controller is used, then the control device is simple and easy to operate, but control accuracy deteriorates due to nonlinear operating characteristics
Solution Approach 1:
The patent transforms the control approach by changing from direct linear control to a two-stage process: first determining actual characteristic values through measurement, then calculating corrected set values that compensate for nonlinearities. This parameter transformation enables accurate control of nonlinear processes while maintaining operational simplicity through automated correction.
2Device complexity
If predetermined correction characteristics are used, then the linearization process is simplified, but control accuracy deteriorates due to approximate linearization
Solution Approach 1:
The system performs self-characterization by automatically determining its own actual characteristic values through measurement and evaluation. The control device independently identifies its nonlinearities and generates appropriate correction characteristics without requiring external manual input or predetermined forms, achieving both simplicity and accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where actual process values are continuously measured, compared with set values, and used to determine correction characteristics. This closed-loop feedback enables the system to adapt to actual nonlinearities and maintain high control accuracy while automating the linearization process.
3Adaptability or versatility
If manual determination of correction characteristics is performed, then flexibility is improved, but device complexity and time consumption increase
Solution Approach 1:
The control device automatically determines correction characteristics through self-characterization, eliminating the need for manual intervention. The system independently performs measurement, evaluation, and calculation of corrected set values, achieving both flexibility in adapting to actual nonlinearities and efficiency in reducing time consumption.
4Measurement precision
If a wrongly dimensioned process valve is used, then the control loop appears optimized during linearization, but optimal control results cannot be achieved
Solution Approach 1:
The system continuously measures actual process values and compares them with corrected set values, using this feedback to identify deviations caused by improper valve dimensioning. The automated evaluation process can detect when linearization corrections are insufficient, indicating potential valve sizing issues that require attention.
Data Source
AI summary
A method and a device for open-loop or closed-loop control of a process uses an actuator, a position sensor, a process valve, a process sensor, and a tuning stage. n positions of the process valve are approached, and the associated actual position values are detected. The respective actual process values are detected for each corresponding actual position value to thus obtain value pairs of actual position values and actual process values. Correction values are calculated based on the identified value pairs, and position set values corrected with the correction values are determined to compensate for nonlinearities of the process, such that a linear overall behavior is achieved.