US 6,314,333 B1Granted

Method and apparatus for controlling web tension by actively controlling velocity and acceleration of a dancer roll

AssigneeKimberly-Clark Worldwide, Inc.

InventorsGregory John Rajala, Robert Donald Lorenz

Life of this patent

Estimating the term…

Loading patent…

Abstract

This invention pertains to processing continuous webs such as paper, film, composites, and the like, in dynamic continuous processing operations. More particularly, it relates to controlling tension in such continuous webs during the processing operation. Tension is controlled in a dancer control system by connecting a corresponding dancer roll to an actuator apparatus or the like, sensing variables such as position, tension, velocity, and acceleration parameters related to the web and the dancer roll, and providing active force commands, in response to the sensed variables, to cause translational movement, generally including a target acceleration, in the dancer roll to control tension disturbances in the web. In some applications of the invention, the dancer control system is used to attenuate tension disturbances. In other applications of the invention, the dancer control system is used to create tension disturbances.

Claims85

Dependent claims

Processing apparatus for advancing a continuous web of material through a processing step along a given section of the web, the processing apparatus comprising:

(a) a dancer roll operative for controlling tension on the respective section of web;
(b) actuator apparatus for applying a first static force component, to said dancer roll, having a first value and direction, and balancing said dancer roll against static forces and the average dynamic tension in the respective section of the web;
(c) a controller connected to said actuator apparatus, said controller outputting a second variable force component, through said actuator apparatus, effective to control the net actuating force imparted to said dancer roll by said actuator apparatus, and to periodically adjust the value and direction of the second variable force component, each such value and direction of the second variable force component replacing the previous such value and direction of the second variable force component, and acting in combination with the first static force component to impart a target net translational acceleration to said dancer roll, the second variable force component having a second value and direction, modifying the first static force component, such that the net translational acceleration of said dancer roll is controlled by the net actuating force enabling said dancer roll to control the web tension;
and
(d) apparatus for computing acceleration (Ap) of said dancer roll, said controller comprising a computer controller providing control commands to said actuator apparatus based on the computed acceleration of said dancer roll.

2 more elements

Processing apparatus for advancing a continuous web of material through a processing step along a given section of the web, the processing apparatus comprising:

(a) a dancer roll operative for controlling tension on the respective section of web;
(b) actuator apparatus connected to said dancer roll and thereby providing an actuating force to said dancer roll;
(c) first apparatus for measuring a first velocity of the web after said dancer roll;
(d) second apparatus for measuring a second velocity of the web at said dancer roll;
(e) third apparatus for measuring motor current of said actuator apparatus;
(f) fourth apparatus for measuring web tension before said dancer roll;
(g) fifth apparatus for measuring web tension after said dancer roll;
(h) sixth apparatus for measuring acceleration of said dancer roll;
and
(i) a controller for providing force control commands to said actuator apparatus based on the above measured values, including computed acceleration A*p of said dancer roll, said controller thereby controlling the actuating force imparted to said dancer roll by said actuator apparatus to control the web tension.

7 more elements

In a processing operation wherein a continuous web of material is advanced through a processing step, a method of controlling the tension in the respective section of the web, comprising:

(a) providing a dancer roll operative for controlling tension on the respective section of web;
(b) providing actuator apparatus to apply an actuating force to the dancer roll;
(c) measuring a first velocity of the web after the dancer roll;
(d) measuring a second velocity of the web at the dancer roll;
(e) measuring motor current of the actuator apparatus;
(f) measuring web tension before the dancer roll;
(g) measuring web tension after the dancer roll;
and
(h) providing force control commands to the actuator apparatus based on the above measured values, including computed acceleration A*p of the dancer roll, to thereby control the actuating force imparted to the dancer roll by the actuator apparatus to control the web tension.

6 more elements

Dependencies are inferred from the claim text.