MODELING OF WEB-ROLLER INTERACTIONS AND LATERAL WEB DYNAMICS

Three distributed parameter models for the lateral dynamic behavior of a moving web in an n-roller system are investigated. A span of web, moving longitudinally and under tension, was modeled as either a string, a Bernoulli-Euler beam, or a Timoshenko beam. A quasi-static simplification based upon spectral separation is made to simplify the model. Boundary conditions at the web-roller interface are determined from the kinematics of web-roller interaction. Actuator dynamics are introduced through the formulation of the boundary conditions. Closed-loop simulations, using a state space version of the simplified model, are in agreement with experimental results only when the web is modeled as a Timoshenko beam.