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US 2003/0156344 A1Published application
Eccentricity compensation in a web handling system
AssigneeInternational Business Machines Corporation
InventorsAlex Chliwnyj, David Michael Davis, David Lee Swanson
Life of this patent
Estimating the term…
Abstract
A control system compensates for web tension variation caused by a first spool, (A) determines rotational frequency of the first spool; (B) determines variation in rotational velocity at the second spool which occurs at the (A) first spool frequency; (C) determines the rotational position at the first spool corresponding to the (B) variation in rotational velocity at the second spool; (D) calculates a drive motor profile for the first spool which tends to cancel the (B) variation in rotational velocity at the second spool; and (E) superimposes the (D) drive motor profile on a first spool drive motor at the (C) determined rotational position of the first spool.
Claims36
In a web handling system comprising, respectively, a first spool, a first drive motor for rotating said first spool, and a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- and a second spool, a second drive motor for rotating said second spool, and a second tachometer;
- said web handling system for respectively winding and unwinding a web with respect to said spools to transport said web between said spools under tension;
- a method for compensating for web tension variation caused by said first spool, comprising the steps of:
- (A) determining, from said first tachometer, the rotational frequency of said first spool;
- (B) determining, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said step (A) determined rotational frequency of said first spool;
- (C) determining, from said first tachometer index indication, the rotational position at said first spool corresponding to said step (B) determined variation in rotational velocity at said second spool;
- (D) calculating a drive motor profile for operating said first drive motor which tends to cancel said step (B) determined variation in rotational velocity at said second spool;
- and
- (E) superimposing said step (D) drive motor profile on said first drive motor at said step (C) determined rotational position of said first spool.
6 more elements
In a web handling system comprising, respectively, a first spool, a first drive motor for rotating said first spool, and a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- and a second spool, a second drive motor for rotating said second spool, and a second tachometer;
- said web handling system for respectively winding and unwinding a web with respect to said spools to transport said web between said spools under tension;
- a method for compensating for web tension variation caused by said first spool, comprising the steps of:
- (0) initializing operation of said drive motors for rotating said spools upon said web having substantially different diameters at each of said spools, such that said spools are rotated at substantially different rotational frequencies;
- (A) determining, from said first tachometer, the rotational frequency of said first spool;
- (B) determining, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said step (A) determined rotational frequency of said first spool;
- (C) determining, from said first tachometer index indication, the rotational position at said first spool corresponding to said step (B) determined variation in rotational velocity at said second spool;
- (D) calculating a drive motor profile for operating said first drive motor which tends to cancel said step (B) determined variation in rotational velocity at said second spool;
- and
- (E) superimposing said step (D) drive motor profile on said first drive motor at said step (C) determined rotational position of said first spool.
7 more elements
In a web handling system comprising, respectively, a first spool, a first drive motor for rotating said first spool, and a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- and a second spool, a second drive motor for rotating said second spool, and a second tachometer, said second tachometer having an index indication;
- said web handling system for respectively winding and unwinding a web with respect to said spools to transport said web between said spools under tension;
- a method for compensating for web tension variation caused by said spools, comprising the steps of:
- (1A) determining, from said first tachometer, the rotational frequency of said first spool;
- (1B) determining, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said step (1A) determined rotational frequency of said first spool;
- (1C) determining, from said first tachometer index indication, the rotational position at said first spool corresponding to said step (1B) determined variation in rotational velocity at said second spool;
- (1D) calculating a first drive motor profile for operating said first drive motor which tends to cancel said step (1B) determined variation in rotational velocity at said second spool;
- (1E) superimposing said step (1D) drive motor profile on said first drive motor at said step (1C) determined rotational position of said first spool;
- (2A) determining, from said second tachometer, the rotational frequency of said second spool;
- (2B) determining, from said first tachometer, variation in rotational velocity at said first spool which occurs at the frequency of said step (2A) determined rotational frequency of said second spool;
- (2C) determining, from said second tachometer index indication, the rotational position at said second spool corresponding to said step (2B) determined variation in rotational velocity at said first spool;
- (2D) calculating a second drive motor profile for operating said second drive motor which tends to cancel said step (2B) determined variation in rotational velocity at said first spool;
- and
- (2E) superimposing said step (2D) drive motor profile on said second drive motor at said step (2C) determined rotational position of said second spool.
11 more elements
In a web handling system comprising, respectively, a first spool, a first drive motor for rotating said first spool, and a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- and a second spool, a second drive motor for rotating said second spool, and a second tachometer, said second tachometer having an index indication;
- said web handling system for respectively winding and unwinding a web with respect to said spools to transport said web between said spools under tension;
- a method for compensating for web tension variation caused by said spools, comprising the steps of:
- (0) initializing operation of said drive motors for rotating said spools upon said web having substantially different diameters at each of said spools, such that said spools are rotated at substantially different rotational frequencies;
- (1A) determining, from said first tachometer, the rotational frequency of said first spool;
- (1B) determining, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said step (1A) determined rotational frequency of said first spool;
- (1C) determining, from said first tachometer index indication, the rotational position at said first spool corresponding to said step (1B) determined variation in rotational velocity at said second spool;
- (1D) calculating a first drive motor profile for operating said first drive motor which tends to cancel said step (1B) determined variation in rotational velocity at said second spool;
- (1E) superimposing said step (1D) drive motor profile on said first drive motor at said step (1C) determined rotational position of said first spool;
- (2A) determining, from said second tachometer, the rotational frequency of said second spool;
- (2B) determining, from said first tachometer, variation in rotational velocity at said first spool which occurs at the frequency of said step (2A) determined rotational frequency of said second spool;
- (2C) determining, from said second tachometer index indication, the rotational position at said second spool corresponding to said step (2B) determined variation in rotational velocity at said first spool;
- (2D) calculating a second drive motor profile for operating said second drive motor which tends to cancel said step (2B) determined variation in rotational velocity at said first spool;
- and
- (2E) superimposing said step (2D) drive motor profile on said second drive motor at said step (2C) determined rotational position of said second spool.
12 more elements
A web handling system comprising:
- a first spool;
- a first drive motor for rotating said first spool;
- a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- a second spool;
- a second drive motor for rotating said second spool;
- a second tachometer;
- and
- a control system coupled to said first drive motor, said first tachometer, said second drive motor and said second tachometer, said control system operating said first and said second drive motors for respectively winding and unwinding a web with respect to said spools to transport said web between said spools under tension;
- said control system compensating for web tension variation caused by said first spool, said control system:
- (A) determines, from said first tachometer, the rotational frequency of said first spool;
- (B) determines, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said (A) determined rotational frequency of said first spool;
- (C) determines, from said first tachometer index indication, the rotational position at said first spool corresponding to said (B) determined variation in rotational velocity at the frequency of said second spool;
- (D) calculates a drive motor profile for operating said first drive motor which tends to cancel said (B) determined variation in rotational velocity at said second spool;
- and
- (E) superimposes said (D) drive motor profile on said first drive motor at said (C) determined rotational position of said first spool.
12 more elements
A web handling system comprising:
- a first spool;
- a first drive motor for rotating said first spool;
- a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- a second spool;
- a second drive motor for rotating said second spool;
- a second tachometer;
- and
- a control system coupled to said first drive motor, said first tachometer, said second drive motor and said second tachometer, said control system operating said first and said second drive motors for respectively winding and unwinding a web with respect to said spools to transport said web between said spools under tension;
- said control system compensating for web tension variation caused by said first spool, said control system:
- (0) initializes operation of said drive motors to rotate said spools upon said web having substantially different diameters at each of said spools, such that said spools are rotated at substantially different rotational frequencies;
- (A) determines, from said first tachometer, the rotational frequency of said first spool;
- (B) determines, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said (A) determined rotational frequency of said first spool;
- (C) determines, from said first tachometer index indication, the rotational position at said first spool corresponding to said (B) determined variation in rotational velocity at said second spool;
- (D) calculates a drive motor profile for operating said first drive motor which tends to cancel said (B) determined variation in rotational velocity at said second spool;
- and
- (E) superimposes said (D) drive motor profile on said first drive motor at said (C) determined rotational position of said first spool.
13 more elements
A web handling system comprising:
- a first spool;
- a first drive motor for rotating said first spool;
- a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- a second spool;
- a second drive motor for rotating said second spool;
- a second tachometer, said second tachometer having an index indication;
- and
- a control system coupled to said first drive motor, said first tachometer, said second drive motor and said second tachometer;
- said control system operating said first and said second drive motors for respectively winding and unwinding a web with respect to said spools to transport said web between said spools under tension;
- said control system compensating for web tension variation caused by said spools, said control system:
- (1A) determines, from said first tachometer, the rotational frequency of said first spool;
- (1B) determines, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said (1A) determined rotational frequency of said first spool;
- (1C) determines, from said first tachometer index indication, the rotational position at said first spool corresponding to said (1B) determined variation in rotational velocity at said second spool;
- (1D) calculates a first drive motor profile for operating said first drive motor which tends to cancel said (1B) determined variation in rotational velocity at said second spool;
- (1E) superimposes said (1D) drive motor profile on said first drive motor at said (1C) determined rotational position of said first spool;
- (2A) determines, from said second tachometer, the rotational frequency of said second spool;
- (2B) determines, from said first tachometer, variation in rotational velocity at said first spool which occurs at the frequency of said (2A) determined rotational frequency of said second spool;
- (2C) determines, from said second tachometer index indication, the rotational position at said second spool corresponding to said (2B) determined variation in rotational velocity at said first spool;
- (2D) calculates a second drive motor profile for operating said second drive motor which tends to cancel said (2B) determined variation in rotational velocity at said first spool;
- and
- (2E) superimposes said (2D) drive motor profile on said second drive motor at said (2C) determined rotational position of said second spool.
18 more elements
A web handling system comprising:
- a first spool;
- a first drive motor for rotating said first spool;
- a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- a second spool;
- a second drive motor for rotating said second spool;
- a second tachometer, said second tachometer having an index indication;
- and
- a control system coupled to said first drive motor, said first tachometer, said second drive motor and said second tachometer;
- said control system operating said first and said second drive motors for respectively winding and unwinding a web with respect to said spools to transport said web between said spools under tension;
- said control system compensating for web tension variation caused by said spools, said control system:
- (0) initializes operation of said drive motors to rotate said spools upon said web having substantially different diameters at each of said spools, such that said spools are rotated at substantially different rotational frequencies;
- (1A) determines, from said first tachometer, the rotational frequency of said first spool;
- (1B) determines, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said (1A) determined rotational frequency of said first spool;
- (1C) determines, from said first tachometer index indication, the rotational position at said first spool corresponding to said (1B) determined variation in rotational velocity at said second spool;
- (1D) calculates a first drive motor profile for operating said first drive motor which tends to cancel said (1B) determined variation in rotational velocity at said second spool;
- (1E) superimposes said (1D) drive motor profile on said first drive motor at said (1C) determined rotational position of said first spool;
- (2A) determines, from said second tachometer, the rotational frequency of said second spool;
- (2B) determines, from said first tachometer, variation in rotational velocity at said first spool which occurs at the frequency of said (2A) determined rotational frequency of said second spool;
- (2C) determines, from said second tachometer index indication, the rotational position at said second spool corresponding to said (2B) determined variation in rotational velocity at said first spool;
- (2D) calculates a second drive motor profile for operating said second drive motor which tends to cancel said (2B) determined variation in rotational velocity at said first spool;
- and
- (2E) superimposes said (2D) drive motor profile on said second drive motor at said (2C) determined rotational position of said second spool.
19 more elements
A magnetic tape drive for reading and/or writing data on a magnetic tape, comprising:
- a first drive motor for rotating a first spool for winding and unwinding a magnetic tape;
- a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- a second drive motor for rotating a second spool for winding and unwinding a magnetic tape;
- a second tachometer;
- at least one read and/or write head positioned so as to be intermediate said first and said second spools along a tape path, for reading and/or writing data to a magnetic tape as it is transported along said tape path between said first and said second spools when being respectively wound and unwound with respect to said first and said second spools;
- and
- a control system coupled to said first drive motor, said first tachometer, said second drive motor and said second tachometer, said control system operating said first and said second drive motors for respectively winding and unwinding a magnetic tape with respect to said spools to transport said magnetic tape between said spools under tension;
- said control system compensating for magnetic tape tension variation caused by said first spool, said control system:
- (A) determines, from said first tachometer, the rotational frequency of said first spool;
- (B) determines, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said (A) determined rotational frequency of said first spool;
- (C) determines, from said first tachometer index indication, the rotational position at said first spool corresponding to said (B) determined variation in rotational velocity at said second spool;
- (D) calculates a drive motor profile for operating said first drive motor which tends to cancel said (B) determined variation in rotational velocity at said second spool;
- and
- (E) superimposes said (D) drive motor profile on said first drive motor at said (C) determined rotational position of said first spool.
11 more elements
A magnetic tape drive for reading and/or writing data on a magnetic tape, comprising:
- a first drive motor for rotating a first spool for winding and unwinding a magnetic tape;
- a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- a second drive motor for rotating a second spool for winding and unwinding a magnetic tape;
- a second tachometer;
- at least one read and/or write head positioned so as to be intermediate said first and said second spools along a tape path, for reading and/or writing data to a magnetic tape as it is transported along said tape path between said first and said second spools when being respectively wound and unwound with respect to said first and said second spools;
- and
- a control system coupled to said first drive motor, said first tachometer, said second drive motor and said second tachometer, said control system operating said first and said second drive motors for respectively winding and unwinding a magnetic tape with respect to said spools to transport said magnetic tape between said spools under tension;
- said control system compensating for magnetic tape tension variation caused by said first spool, said control system:
- (0) initializes operation of said drive motors to rotate said spools upon said magnetic tape having substantially different diameters at each of said spools, such that said spools are rotated at substantially different rotational frequencies;
- (A) determines, from said first tachometer, the rotational frequency of said first spool;
- (B) determines, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said (A) determined rotational frequency of said first spool;
- (C) determines, from said first tachometer index indication, the rotational position at said first spool corresponding to said (B) determined variation in rotational velocity at said second spool;
- (D) calculates a drive motor profile for operating said first drive motor which tends to cancel said (B) determined variation in rotational velocity at said second spool;
- and
- (E) superimposes said (D) drive motor profile on said first drive motor at said (C) determined rotational position of said first spool.
12 more elements
A magnetic tape drive for reading and/or writing data on a magnetic tape, comprising:
- a first drive motor for rotating a first spool for winding and unwinding a magnetic tape;
- a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- a second drive motor for rotating a second spool for winding and unwinding a magnetic tape;
- a second tachometer, said second tachometer having an index indication;
- at least one read and/or write head positioned so as to be intermediate said first and said second spools along a tape path, for reading and/or writing data to a magnetic tape as it is transported along said tape path between said first and said second spools when being respectively wound and unwound with respect to said first and said second spools;
- and
- a control system coupled to said first drive motor, said first tachometer, said second drive motor and said second tachometer;
- said control system operating said first and said second drive motors for respectively winding and unwinding a magnetic tape with respect to said spools to transport said magnetic tape between said spools under tension;
- said control system compensating for magnetic tape tension variation caused by said spools, said control system:
- (1A) determines, from said first tachometer, the rotational frequency of said first spool;
- (1B) determines, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said (1A) determined rotational frequency of said first spool;
- (1C) determines, from said first tachometer index indication, the rotational position at said first spool corresponding to said (1B) determined variation in rotational velocity at said second spool;
- (1D) calculates a first drive motor profile for operating said first drive motor which tends to cancel said (1B) determined variation in rotational velocity at said second spool;
- (1E) superimposes said (1D) drive motor profile on said first drive motor at said (1C) determined rotational position of said first spool;
- (2A) determines, from said second tachometer, the rotational frequency of said second spool;
- (2B) determines, from said first tachometer, variation in rotational velocity at said first spool which occurs at the frequency of said (2A) determined rotational frequency of said second spool;
- (2C) determines, from said second tachometer index indication, the rotational position at said second spool corresponding to said (2B) determined variation in rotational velocity at said first spool;
- (2D) calculates a second drive motor profile for operating said second drive motor which tends to cancel said (2B) determined variation in rotational velocity at said first spool;
- and
- (2E) superimposes said (2D) drive motor profile on said second drive motor at said (2C) determined rotational position of said second spool.
17 more elements
A magnetic tape drive for reading and/or writing data on a magnetic tape, comprising:
- a first drive motor for rotating a first spool for winding and unwinding a magnetic tape;
- a first tachometer for indicating the rotary position of said first spool, said first tachometer having an index indication;
- a second drive motor for rotating a second spool for winding and unwinding a magnetic tape;
- a second tachometer, said second tachometer having an index indication;
- at least one read and/or write head positioned so as to be intermediate said first and said second spools along a tape path, for reading and/or writing data to a magnetic tape as it is transported along said tape path between said first and said second spools when being respectively wound and unwound with respect to said first and said second spools;
- and
- a control system coupled to said first drive motor, said first tachometer, said second drive motor and said second tachometer;
- said control system operating said first and said second drive motors for respectively winding and unwinding a magnetic tape with respect to said spools to transport said magnetic tape between said spools under tension;
- said control system compensating for magnetic tape tension variation caused by said spools, said control system:
- (0) initializes operation of said drive motors to rotate said spools upon said magnetic tape having substantially different diameters at each of said spools, such that said spools are rotated at substantially different rotational frequencies;
- (1A) determines, from said first tachometer, the rotational frequency of said first spool;
- (1B) determines, from said second tachometer, variation in rotational velocity at said second spool which occurs at the frequency of said (1A) determined rotational frequency of said first spool;
- (1C) determines, from said first tachometer index indication, the rotational position at said first spool corresponding to said (1B) determined variation in rotational velocity at said second spool;
- (1D) calculates a first drive motor profile for operating said first drive motor which tends to cancel said (1B) determined variation in rotational velocity at said second spool;
- (1E) superimposes said (1D) drive motor profile on said first drive motor at said (1C) determined rotational position of said first spool;
- (2A) determines, from said second tachometer, the rotational frequency of said second spool;
- (2B) determines, from said first tachometer, variation in rotational velocity at said first spool which occurs at the frequency of said (2A) determined rotational frequency of said second spool;
- (2C) determines, from said second tachometer index indication, the rotational position at said second spool corresponding to said (2B) determined variation in rotational velocity at said first spool;
- (2D) calculates a second drive motor profile for operating said second drive motor which tends to cancel said (2B) determined variation in rotational velocity at said first spool;
- and
- (2E) superimposes said (2D) drive motor profile on said second drive motor at said (2C) determined rotational position of said second spool.
18 more elements
Dependencies are inferred from the claim text.