Automatic Relay-Based Controller Tuning
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Solution Overview
Problem
Conventional methods for tuning PID controller parameters in industrial control systems are cumbersome, time-consuming, and require human intervention, often necessitating prior knowledge of relay parameters.
Innovation Solution
A method and arrangement for automatically estimating relay parameters by acquiring controller and system output data during steady-state conditions, determining a safe relay amplitude, and using it to perform relay-based controller tuning without user intervention, ensuring safety and efficiency in determining controller parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If manual tuning or conventional Ziegler-Nichols method is applied, then controller parameters can be determined, but operator intervention and prior knowledge of relay parameters are required making the process cumbersome and time-consuming
Solution Approach 1:
The system performs self-tuning by automatically detecting steady-state conditions, calculating appropriate relay parameters, and executing the tuning process without operator intervention. The controller monitors its own output and system response to determine when steady-state has been reached and calculates the relay amplitude needed for tuning.
Solution Approach 2:
The system performs preliminary detection of steady-state conditions and pre-calculates the relay parameters before executing the tuning test. This preparation phase ensures that when the relay test is initiated, all necessary parameters are already determined, enabling immediate automated tuning without requiring operator input.
2Reliability
If relay-based tuning is performed without automated parameter determination, then tuning can be completed, but human intervention increases the risk of human error and system damage
Solution Approach 1:
The system automatically monitors controller output and system response to detect steady-state conditions, eliminating the need for operator judgment. The controller itself determines when it is safe to proceed with relay testing based on predefined criteria, reducing human error while maintaining safety.
Solution Approach 2:
The system continuously monitors the controller output and system response during the tuning process, using this feedback to determine when steady-state has been achieved and to adjust the relay parameters accordingly. This closed-loop feedback ensures safe operation while maintaining full automation.
3Ease of manufacture
If conventional tuning methods are used, then controller parameters can be determined, but the process requires a priori knowledge of relay parameters increasing complexity
Solution Approach 1:
The controller automatically determines the relay parameters needed for tuning by analyzing its own output characteristics and system response. No external knowledge or manual configuration of relay parameters is required - the system calculates everything needed based on its operational data.
Solution Approach 2:
The system pre-calculates all necessary relay parameters including amplitude and hysteresis by monitoring steady-state conditions before the tuning test begins. This preliminary determination of parameters simplifies the overall process by eliminating the need for operators to have specialized knowledge of relay configuration.
Data Source
AI summary
A method is described for acquiring data for relay-based controller tuning of a controller controlling a system. The method includes determining, based on controller output constraint, a relay amplitude representing an amplitude of a relay signal to be added to steady state controller output to obtain a sum signal to be fed to the system as system input during the acquiring data for relay-based controller tuning; and starting acquiring controller output data and system output data when detecting a steady state of system output while controller output is fed to the system as system input.