Theoretical Analysis of a Servo-Controlled Film-Tension System

Since 1945 there has been a tremendous advance in the theory of servo-mechanisms; in the motion-picture industry there have been a number of advances in the design of film take-up and tension devices, but most of these designs appear to have been rather empirical. A set of solutions and dimensionless graphs is presented which may be employed in solving some of these problems. A general analysis of a simple servo system such as might be used for a film take-up, film feed or a constant tension device shows how the initial differential equations are derived and then solved via Laplace transforms. The solutions are given in the time domain. The results are graphs in generalized coordinates from which tension overshoot, time of maximum overshoot and steady-state error may be predicted. Included in the analysis are tachometer and network compensation. Also included are the proper selection of motors, gear ratios and tension arms.

Print ISSN

0361-4573

Published

1971-10

Content type

Original Research

DOI

10.5594/J05731