| Discontinuous unwinding tension control, which is characterized by strong coupling andinterference, is an extremely important link in the film roll-to-roll conveyance system andfrequent stop-start and acceleration-deceleration increase the complexity of the control system.This thesis begins with unwinding tension control system modeling, relevant to various tensioncontrol mechanism and components， followed by simulation analysis and experimentalresearch, thus verifying the feasibility of the system. The main contributions of this thesis canbe summarized as follows:1. Establish discontinuous unwinding tension model and deduce the linear relationshipbetween tension fluctuation and the acceleration in the discontinuous deceleration phase.Investigate the influence of unwinding speed, roll diameter, roundness, eccentricity onunwinding steady tension.2. Present closed-loop unwinding tension control technique based on the pendulum anglefeedback through analysis of the pendulum roller mechanism and the linear relationshipbetween tension fluctuation and pendulum angle. Floating roller mechanism with low frictioncylinder has the advantage of real-time, high precise of adjustment, bidirectional according tothe comparison on floating roller mechanism with different tension control component.3. Unwinding tension curve obtained based on adaptive PID control algorithm is fast inresponse, high instability, small in overshoots, and tension fluctuation is with a remarkableperiodicity, which increases with the decrease of the roll diameter in the same accelerationcondition and presents a linear relationship with acceleration in the same roll diametercondition. While the tension curve obtained based on the model with pendulum angle asfeedback has longer response time, but smaller fluctuations and higher stability, which showsthat pendulum roller mechanism can effectively suppress the unwinding tension fluctuation.4. Develop the unwinding tension experiment with slip shaft, the magnetic powder brake,and AC servo motor based on the flexibility film roll-to-roll conveyance platform, which showsthat unwinding tension control with AC servo motor is better, the steady tension is higher inconsistency, and the relationship between tension fluctuation amplitude of magnetic powderbrake and acceleration is almost linear. Adding pendulum roller mechanism or floating rollermechanism to the feeding end can suppress unwinding tension fluctuation, verifying the validity of the unwinding tension model and the simulation.In short, various tension control schemes are proposed according to the modeling, analysisand experimental comparison, revealing that the steady tension control of scheme with ACservo motor and floating roller mechanism is preferred in the discontinuous film transportation,which has been applied practically in RFID tag manufacturing system equipment. |
