scholarly journals A New Method for Making a Reduced-Order Model of Flexible Structures using Unobservability and Uncontrollability and Its Application in Vibration Control

1994 ◽  
Vol 37 (3) ◽  
pp. 444-449 ◽  
Author(s):  
Kazuto Seto ◽  
Shinji Mitsuta
Keyword(s):  
Vibration Control ◽  
Flexible Structures ◽  
Reduced Order Model ◽  
New Method ◽  
Order Model ◽  
Reduced Order

Experimental Study on Arrangements of Setting Points of an Actuator and Sensor for the Vibration Control of Flexible Structures

1994 ◽  
Vol 6 (4) ◽  
pp. 292-297
Author(s):  
Kazuto Seto ◽  
◽  
Katsuhiko Ezure ◽  
Keyword(s):  
Experimental Study ◽  
Vibration Control ◽  
Vibration Mode ◽  
Controller Design ◽  
Flexible Structures ◽  
Reduced Order Model ◽  
Displacement Sensor ◽  
Order Model ◽  
Reduced Order ◽  
Dynamic Absorber

This paper proposes an experimental study on the arrangements between the setting points of an actuator and sensor for the vibration control of a flexible structure, when a vibration controller is mounted at an arbitrary position on the structure. The important vibration mode of the structure to be controlled is its first mode, because it is excited most sensitively by strong winds. It is therefore necessary to make a reduced-order model represented by a one-degree-of-freedom system at an arbitrary location, in consideration of preventing spillover instability. In this paper, non-observability is used for making the reduced-order model, and the LQ control theory is used for controller design. For controlling vibration, a reduced-order model is constructed at the setting point of a hybrid dynamic absorber, and a displacement sensor is set at the vibration node of the second vibration mode. Then, the setting point of the sensor is changed to compare control effects by means of this model. It is demonstrated experimentally that a hybrid dynamic absorber, designed by this method, is capable of controlling vibration well without causing spillover instability. In addition, it is considered that the setting point of the sensor influences the robustness of the control system.

Mistuning Identification of Bladed Disks Using a Fundamental Mistuning Model—Part I: Theory

2004 ◽  
Vol 126 (1) ◽  
pp. 150-158 ◽  
Author(s):  
D. M. Feiner ◽  
J. H. Griffin
Keyword(s):  
Experimental Data ◽  
System Identification ◽  
Prior Knowledge ◽  
Reduced Order Model ◽  
New Method ◽  
Order Model ◽  
Bladed Disks ◽  
Reduced Order ◽  
Vibratory Response ◽  
Basic Version

This paper is the first in a two-part study of identifying mistuning in bladed disks. It develops a new method of mistuning identification based on measurements of the vibratory response of the system as a whole. As a system-based method, this approach is particularly suited to integrally bladed rotors, whose blades cannot be removed for individual measurements. The method is based on a recently developed reduced order model of mistuning called the fundamental mistuning model (FMM) and is applicable to isolated families of modes. Two versions of FMM system identification are presented: a basic version that requires some prior knowledge of the system’s properties, and a somewhat more complex version that determines the mistuning completely from experimental data.

Vibration Control Method and Adaptability for Flexible Structures With Distributed Parameters Using a Hybrid Dynamic Absorber

1995 ◽  
Author(s):  
Kazuto Seto ◽  
Susumu Kondo ◽  
Katsuhiko Ezure
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Controller Design ◽  
Flexible Structures ◽  
Vibration Modes ◽  
Order Model ◽  
Reduced Order ◽  
Distributed Parameters ◽  
Dynamic Absorber ◽  
Lq Control

Abstract This paper examines the vibration control of a flexible structure using a hybrid dynamic absorber. A new method for modeling flexible structures with distributed parameters using a reduced-order model with lumped parameters is specified. Both prevention of spillover and physical correspondence at the modeling points are taken into consideration. Due to restrictions of controller design it is necessary to employ reduced-order models of flexible structures when using LQ control theory to control vibration. By ignoring higher mode orders model reduction may invite vibration instability called spillover. In order to prevent spillover nodes of higher-order vibration modes are selected as modeling points. The effectiveness of this method is demonstrated by applying vibration control to a flexible tower-like structure. In addition the robustness of the control system is tested by placing the sensors and absorbers at points different from those selected by the model.

Mistuning Identification of Bladed Disks Using a Fundamental Mistuning Model: Part 1 — Theory

2003 ◽  
Author(s):  
D. M. Feiner ◽  
J. H. Griffin
Keyword(s):  
Experimental Data ◽  
System Identification ◽  
Prior Knowledge ◽  
Reduced Order Model ◽  
New Method ◽  
Order Model ◽  
Bladed Disks ◽  
Reduced Order ◽  
Vibratory Response ◽  
Basic Version

This paper is the first in a two-part study of identifying mistuning in bladed disks. It develops a new method of mistuning identification based on measurements of the vibratory response of the system as a whole. As a system-based method, this approach is particularly suited to integrally bladed rotors, whose blades cannot be removed for individual measurements. The method is based on a recently developed reduced order model of mistuning called the Fundamental Mistuning Model, FMM, and is applicable to isolated families of modes. Two versions of FMM system identification are presented: a basic version that requires some prior knowledge of the system’s properties, and a somewhat more complex version that determines the mistuning completely from experimental data.

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