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US 2002/0177919 A1Published application
Method and apparatus for identifying mapping of paper machine actuator
AssigneeMetso Paper Automation Oy
InventorsTapio Metsala, John Shakespeare
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Abstract
A method and an apparatus for identifying mapping of a paper machine by means of a mapping test. The invention comprises forming a mapping model which takes the linear and non-linear shrinkage of a paper web into account. The mapping test result is analyzed to form a non-linear shrinkage profile and a linear mapping error from it. The linear error and the non-linear shrinkage profile thus obtained are used in the mapping model.
Claims13
A method of identifying mapping of a paper machine actuator in a paper making process, the method comprising
- a) performing a mapping test to obtain a mapping test result,
- b) forming a non-linear shrinkage profile of the paper web,
- c) eliminating the effect of the non-linear shrinkage profile from the mapping test result,
- d) forming a straight line from the result obtained in step c),
- e) forming a first mapping model which does not include the effect of the non-linear shrinkage profile
- f) comparing the straight line formed in step d) with the mapping model formed in step e) to produce a first linear mapping error,
- g) forming a second mapping model utilizing the non-linear shrinkage profile,
- h) comparing the mapping model formed in step g) with the result of the mapping test to produce a second linear mapping error,
- i) forming the total error of linear errors from the difference between the first linear mapping error and the second linear mapping error,
- j) determining the magnitude allowed for the total error of linear errors, and
- k) comparing the magnitude of the total error of linear errors produced with the allowed magnitude of the total error of linear errors, and if the total error of linear errors is sufficiently small, concluding that the linear errors indicate a linear error in the mapping model, and that the currently used non-linear shrinkage profile indicates the non-linear shrinkage profile to be used in the mapping model with sufficient accuracy, in which case the linear error and non-linear shrinkage profile thus determined are used in the mapping model, and if the total error of linear errors is too great, forming a new non-linear shrinkage profile and repeating method steps c) to k).
8 more elements
An apparatus for identifying mapping of a paper machine actuator, the apparatus comprising means for performing a mapping test to obtain a mapping test result,
- means for forming a non-linear shrinkage profile of the paper web,
- means for eliminating the influence of the non-linear shrinkage profile from the mapping test result and means for forming a straight line from the result,
- means for forming a first mapping model without the effect of the non-linear shrinkage profile,
- means for comparing the straight line formed with the mapping model without the effect of the non-linear shrinkage profile, the means being arranged to produce a first linear mapping error,
- means for forming a second mapping model utilizing the non-linear shrinkage profile,
- means for comparing the mapping model that utilizes the non-linear shrinkage profile with the mapping test result, the means being arranged to produce a second linear mapping error,
- means for comparing the first linear mapping error with the second linear mapping error to produce the total error of linear errors,
- means for determining the magnitude allowed for the total error of linear errors, and
- means for comparing the magnitude of the total error of linear errors with the allowed magnitude, and, if the magnitude is sufficiently small, the linear mapping errors are arranged to form the linear error to be used in the mapping model and the currently used non-linear shrinkage profile is arranged to be used as the non-linear shrinkage profile in the mapping model with sufficient accuracy, and, if the total error of linear errors is too great, the apparatus is arranged to form a new non-linear shrinkage profile of the paper web and to determine a new total error of linear errors.
6 more elements
Dependencies are inferred from the claim text.