Luigi del Re, Huang-Wen Huang-Wen Mei,
"A Sensitivity Study of State Variable Estimators for a Pneumatical Regulated Cylinder"
, in Tagungsband XII World Congress on Scientific Computation, Paris, 1988, Seite(n) 133-136, 1988

Original Titel:

A Sensitivity Study of State Variable Estimators for a Pneumatical Regulated Cylinder

Sprache des Titels:

Englisch

Original Kurzfassung:

Regulatet pneumatical cylinders represent very promising drives for handling machines, provided that a simple control mechanism is found and a rather good precision is achieved. Recently, some models have been introduced to the market.
In order to reduce computation time, a simplified state veriable estimator is normally beeing employed, in the essence a single and double derivator of the position, measured through a very exact optical rule. As the optical rule is quite expensive, it would be interesting to use a less demanding measurement system. However, derivative estimators use to be sensitive to noise.
From a theoretical point of view, better results could be expected from an observer, as more information on the structure of the system would be used. This represents an important increase in computation times, so that the model should be linear and its order kept as small as possible. A pneumatical cylinder obeys to quite non linear laws, and therefore each such observer is surely based upon a poor approximation of the process. In other words, from a practical point of view it is not clear wehether the observer based on an inexact model will prove better than the derivative estimator based on no model at all. Furthermore, the incertitude or slow time dependance of certain parameters worsens the situation.
This paper relates a case stude, in which the influence of measurement noise and parameter variations for the three cases (exact measurement, derivative estimation and observer) was examined.

Sprache der Kurzfassung:

Englisch

Englische Kurzfassung:

Regulatet pneumatical cylinders represent very promising drives for handling machines, provided that a simple control mechanism is found and a rather good precision is achieved. Recently, some models have been introduced to the market.
In order to reduce computation time, a simplified state veriable estimator is normally beeing employed, in the essence a single and double derivator of the position, measured through a very exact optical rule. As the optical rule is quite expensive, it would be interesting to use a less demanding measurement system. However, derivative estimators use to be sensitive to noise.
From a theoretical point of view, better results could be expected from an observer, as more information on the structure of the system would be used. This represents an important increase in computation times, so that the model should be linear and its order kept as small as possible. A pneumatical cylinder obeys to quite non linear laws, and therefore each such observer is surely based upon a poor approximation of the process. In other words, from a practical point of view it is not clear wehether the observer based on an inexact model will prove better than the derivative estimator based on no model at all. Furthermore, the incertitude or slow time dependance of certain parameters worsens the situation.
This paper relates a case stude, in which the influence of measurement noise and parameter variations for the three cases (exact measurement, derivative estimation and observer) was examined.

Journal:

Tagungsband XII World Congress on Scientific Computation, Paris, 1988