Web Winder Tension Control via Speed Feedback Damping
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Solution Overview
Problem
Existing tension control methods for continuous material webs suffer from low damping and vibration issues, particularly in systems with large inertia, limiting their dynamic performance and introducing noise in high-performance applications.
Innovation Solution
A control system that integrates a speed feedback loop into a torque regulated closed-loop tension control mode, operating the main drive unit in velocity mode and the secondary drive unit in a modified torque regulated mode, to enhance system damping and achieve faster tension responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If torque regulated tension control is used, then the control structure is simple, but the system damping is low and vibration occurs
Solution Approach 1:
The patent introduces a speed feedback loop that feeds back the actual speed of the winder to the torque regulator. This feedback mechanism allows the system to dynamically adjust the torque based on actual speed deviations, thereby increasing system damping and reducing vibration without significantly complicating the control structure. The feedback loop transforms the open-loop torque regulation into a closed-loop control system.
Solution Approach 2:
The patent implements dynamic torque regulation by continuously adjusting the torque command based on real-time speed feedback. The torque regulator dynamically modifies the torque output according to the speed error signal, enabling the system to adapt to changing operating conditions and maintain optimal damping characteristics across different operating points.
2Speed
If speed regulated tension control is used, then the dynamic performance is improved, but the crossover frequency is limited by low speed loop bandwidth
Solution Approach 1:
The patent separates the control functions into distinct modules: a torque regulator and a speed feedback loop. The torque regulator handles the primary tension control with high bandwidth, while the speed feedback loop provides damping enhancement. This segmentation allows each module to operate at its optimal bandwidth without being constrained by the limitations of a cascaded speed loop architecture.
Solution Approach 2:
The patent introduces an intermediate speed feedback signal that acts as a mediator between the torque regulator and the plant. This intermediate feedback path provides the necessary damping information to the torque regulator without requiring a full cascaded speed loop structure, thereby maintaining high crossover frequency while improving dynamic performance.
3Speed
If PI controller gains are increased to achieve fast tension response, then the response speed improves, but the system becomes more sensitive to noise and vibration
Solution Approach 1:
The speed feedback loop provides additional damping that counteracts the oscillatory tendencies introduced by high PI controller gains. The feedback mechanism detects speed deviations and generates corrective torque signals that suppress vibrations and reduce noise sensitivity, allowing the use of higher PI gains for faster response without amplifying harmful effects.
Solution Approach 2:
The patent changes the control parameter from pure torque regulation to speed-feedback-enhanced torque regulation. By introducing speed feedback as an additional control parameter, the system achieves faster tension response through optimized PI gains while the speed feedback component simultaneously suppresses noise and vibration sensitivity through active damping.
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
A control system (42) for controlling operation of main and secondary drive units (22, 34) in a web winder system (10) to provide tension control of a continuous material web (12) is disclosed. The control system (42) causes the main drive unit (34) to operate in a velocity mode to set a linear velocity of the continuous material web (12). The control system (42) receives inputs from tension and speed detectors (44) in the web winder system (10) that detect a tension and speed of the continuous material web (12) and causes the secondary drive unit (22) to operate in a modified torque regulated closed-loop tension control mode so as to control a tension in the web material (12), with the control system (42) causing the secondary drive unit (22) to operate according to a torque regulated closed-loop tension control mode and integrate a speed feedback loop into the torque regulated closed-loop tension control mode so as to introduce active damping into the tension control.