Web Tension Control via Dynamic PI PID Parameters
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Solution Overview
Problem
Existing web tension control methods require frequent adaptation when switching materials, leading to unstable control loops and increased production downtime due to the material's modulus of elasticity and speed dependencies, resulting in suboptimal processing quality.
Innovation Solution
Implementing a PI or PID controller with control loop parameters determined by a hyperbolic characteristic curve based on the master axis speed and using a virtual master axis for drive control, allowing for adaptive tension regulation without mechanical coupling, and utilizing the modulus of elasticity to adjust parameters dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the control loop parameters are optimized for a specific material, then the processing quality for that material is improved, but the control loop becomes unstable when the material is changed
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting control loop parameters (Kp, Ki, Kd) based on the modulus of elasticity of the material being processed. The system determines material-specific parameters and uses them to calculate optimal controller settings, allowing the same control system to adapt to different materials while maintaining stable and high-quality processing.
2Adaptability or versatility
If the control loop parameters are optimized for a larger group of materials, then the adaptability to material changes is improved, but the control loop dynamics are not utilized and the setting time is increased
Solution Approach 1:
The patent implements dynamics by making the control loop parameters dynamic rather than static. The system continuously determines the modulus of elasticity of the current material and automatically adjusts the controller parameters in real-time, enabling fast adaptation to material changes without requiring manual re-optimization or lengthy setting periods.
3Productivity
If the machine speed is increased, then the productivity is improved, but the web tension control becomes more difficult and processing quality decreases
Solution Approach 1:
The patent applies parameter changes by adjusting control loop parameters based on machine speed. The system determines optimal parameters for different speed ranges and dynamically adapts the controller settings, enabling stable web tension control across a wide speed range from very low to very high speeds while maintaining processing quality.
Data Source
Figure 1~2
Figure 3
AI summary
Method involves determination of the control loop parameters of the web tension controller (3) according to a characteristic curve predetermined as function and predetermined at several sampling points. The web tension controller makes a PI-control or a PID-control.