Open-Loop System Identification of MIMO Integrator Model

Several techniques have recently been proposed to identify open-loop system models from input-output data obtained while the plant is operating under closed-loop control. So called multi-stage identification techniques are particularly useful in industrial applications where obtaining input-output information in the absence of closed-loop control is often difficult. These open-loop system models can then be employed in the design of more sophisticated closed-loop controllers. This paper introduces a methodology to identify linear open-loop models of gas turbine engines using a multi-stage identification procedure. The procedure utilizes closed-loop data to identify a closed-loop sensitivity function in the first stage and extracts the open-loop plant model in the second stage. The closed-loop data can be obtained by any sufficiently informative experiment from a plant in operation or simulation. We present simulation results here. This is the logical process to follow since using experimentation is often prohibitively expensive and unpractical. Both identification stages use standard open-loop identification techniques. We then propose a series of techniques to validate the accuracy of the identified models against first principles simulations in both the time and frequency domains. Finally, the potential to use these models for control design is discussed.

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Fretting Behavior of Coated and Treated Titanium Alloy Using an Open-Loop System

World Tribology Congress III, Volume 2 ◽

10.1115/wtc2005-63531 ◽

2005 ◽

Author(s):

G. R. Yantio Njankeu ◽

J.-Y. Paris ◽

J. Denape ◽

L. Pichon ◽

J.-P. Rivie`re

Keyword(s):

Titanium Alloy ◽

Relative Motion ◽

High Frequency ◽

Open Loop ◽

Loop System ◽

Test Apparatus ◽

Open Loop System ◽

Wear Rates ◽

Low Wear

Titanium alloys are well known to present poor sliding behaviour and high wear values. Various coatings and treatments have been tested to prevent such an occurrence under fretting conditions at high frequency of displacement (100 Hz). An original test apparatus, using an open-loop system instead of a classical imposed displacement simulator, has been performed to directly display the phenomenon of seizure, defined as the stopping of the relative motion between the contacting elements. A classification of the tested coatings has been proposed on the basis of their capacity to maintain full or partial sliding conditions, to present low wear rates and to prevent seizure.

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Synthesis of Multivariable Controller With Plant Test Data

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2899225 ◽

1994 ◽

Vol 116 (2) ◽

pp. 309-313 ◽

Cited By ~ 1

Author(s):

Jenq-Tzong H. Chan

Keyword(s):

Control System ◽

Test Data ◽

Open Loop ◽

Loop System ◽

Controller Synthesis ◽

System Model ◽

Multivariable Control ◽

Open Loop System ◽

Plant Test ◽

Multivariable Controller

A method to synthesize decoupled multivariable control system from a batch of plant test data is introduced. The method is applicable when the system has more inputs than outputs and is open-loop stable. An advantage of this method is that explicit identification of an open-loop system model is not required for controller synthesis.

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Pseudo-random binary sequence closed-loop system identification error with integration control

Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering ◽

10.1243/09596518jsce794 ◽

2009 ◽

Vol 223 (6) ◽

pp. 877-884 ◽

Cited By ~ 5

Author(s):

Z Ren ◽

G G Zhu

Keyword(s):

System Identification ◽

Closed Loop ◽

Binary Sequence ◽

Open Loop ◽

Loop System ◽

Loop Model ◽

Closed Loop System ◽

Identification Error ◽

Closed Loop Identification ◽

Integral Controller

This paper studies the closed-loop system identification (ID) error when a dynamic integral controller is used. Pseudo-random binary sequence (PRBS) q-Markov covariance equivalent realization (Cover) is used to identify the closed-loop model, and the open-loop model is obtained based upon the identified closed-loop model. Accurate open-loop models were obtained using PRBS q-Markov Cover system ID directly. For closed-loop system ID, accurate open-loop identified models were obtained with a proportional controller, but when a dynamic controller was used, low-frequency system ID error was found. This study suggests that extra caution is required when a dynamic integral controller is used for closed-loop system identification. The closed-loop identification framework also has significant effects on closed-loop identification error. Both first- and second-order examples are provided in this paper.

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