Vibration and Control of a Flexible Rotor in Magnetic Bearings Using Hybrid Method and H∞ Control Theory

1997 ◽  
Vol 119 (1) ◽  
pp. 178-185 ◽  
Author(s):  
T. N. Shiau ◽  
G. J. Sheu ◽  
C. D. Yang
Keyword(s):  
Control Theory ◽  
Hybrid Method ◽  
Control Design ◽  
Expansion Method ◽  
Rotor System ◽  
Magnetic Bearings ◽  
Experimental Simulation ◽  
Model Parameters ◽  
Flexible Rotor ◽  
H2 Control

The vibration and active control of a flexible rotor system with magnetic bearings are investigated using Hybrid Method (HM) and H∞ control theory with consideration of gyroscopic effect. The hybrid method, which combines the merits of the finite element method (FEM) and generalized polynomial expansion method (GPEM) is employed to model the flexible rotor system with small order of plant. The mixed sensitivity problem of H∞ control theory is applied to design the control of system vibration with spillover phenomena for the reduced order plant. The H2 control design is also employed for comparison with the H∞ design. The experimental simulation is used to illustrate the effects of control design. It is shown that the H∞ controller design can be very effective to suppress spillover phenomena. In addition, the H∞ control design has robustness to the variation of the model parameters. The application of the hybrid method (HM) together with H∞ control design is highly recommended for vibration control of flexible rotor systems with magnetic bearings.

scholarly journals Vibration and Control of a Flexible Rotor in Magnetic Bearings Using Hybrid Method and H∞ Control Theory

1994 ◽  
Author(s):  
Ting Nung Shiau ◽  
Geeng Jen Sheu ◽  
Clann Dong Yang
Keyword(s):  
Control Theory ◽  
Hybrid Method ◽  
Controller Design ◽  
Control Design ◽  
Expansion Method ◽  
Rotor System ◽  
Magnetic Bearings ◽  
Experimental Simulation ◽  
Flexible Rotor ◽  
H2 Control

The vibration and active control of a flexible rotor system with magnetic bearings is investigated using Hybrid Method (HM) and H∞ control theory with consideration of gyroscopic effect. The hybrid method which combines the merits of finite element method (FEM) and generalized ploynomial expansion method (GPEM) is employed to model the flexible rotor system with small order of plant. The mixed sensitivity problem of H∞ control theory is applied to design the control of system vibration with spillover phenomena for the reduced order plant. The H2 control design is also employed for the comparison to the H∞ design. The experimental simulation is used to illustrate the effects of control design. It is shown that the H∞ controller design can be very effective to suppress spillover phenomena. In addition, HM control design has robustness to the variation of the parameters of the model. The application of hybrid method (HM) together with H∞ control design is highly recommended for the vibration control of flexible rotor system with magnetic bearings.

Robust Control of the Elastodynamic Vibrations of a Flexible Rotor System With Discontinuous Friction

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Mansour Karkoub
Keyword(s):  
Dynamic Model ◽  
Design Process ◽  
Nonlinear Models ◽  
Control Design ◽  
Rotor System ◽  
Control Technique ◽  
Flexible Rotor ◽  
Highly Nonlinear ◽  
Modeling Errors ◽  
The Difference

The work presented here deals with the control of a flexible rotor system using the μ-synthesis control technique. This technique allows for the inclusion of modeling errors in the control design process in terms of uncertainty weights. The dynamic model of the rotor system, which includes discontinuous friction, is highly nonlinear and has to be linearized around an operating point in order to use μ-synthesis. The difference between the linear and nonlinear models is characterized in terms of uncertainty weights and included in the control design process. The designed controller is robust to uncertainty in the dynamic model, spillover, actuator uncertainty, and noise. The theoretical findings of the μ-synthesis control design are validated through simulations and the results are presented and discussed here.

Estimation of Active Magnetic Bearings (AMB) Dynamic Parameters and Residual Mass Imbalance Using FEM With PID Controller and Identification Algorithm of a Flexible Rotor System Fully Levitated on AMB

2019 ◽  
Author(s):  
Bala Murugan S. ◽  
R. K. Behera
Keyword(s):  
Pid Controller ◽  
Rotor System ◽  
Magnetic Bearings ◽  
Identification Algorithm ◽  
Dynamic Parameters ◽  
Active Magnetic Bearings ◽  
Flexible Rotor ◽  
Residual Mass ◽  
Mass Imbalance ◽  
Least Squares Fit

Abstract The dynamic analyses of rotating systems are always a testing task to obtain the definite results. This paper carries the dynamic modelling, analysis and identification of coupled flexible rotor system supported by an auxiliary Active Magnetic Bearings (AMBs). An identification algorithm is used to estimate the dynamic parameters of AMB, and rotor residual mass imbalance. The proposed algorithm is a right method for the analysis of fully levitated rotor on AMBs. Finite element method is used to model the dynamic flexible rotor system with PID controller. A conventional dynamic condensation technique is implemented in the development of identification algorithm to overcome the difficulty in numerical simulation. The least-squares fit technique is deployed to estimate the dynamic parameters in frequency domain. Then the algorithm is extended to find the misalignment forces and moments at the coupling point. Numerical study is carried to check the correctness of the algorithm. The proposed algorithm is yet to be tested to experimental results from a fully levitated rotor test rig supported with AMBs.

Multi-objective Optimization of a Flexible Rotor in Magnetic Bearings With Critical Speeds and Control Current Constraints

1997 ◽  
Vol 119 (1) ◽  
pp. 186-195 ◽  
Author(s):  
Ting Nung Shiau ◽  
Chun Pao Kuo ◽  
Jiunn Rong Hwang
Keyword(s):  
Expansion Method ◽  
Magnetic Bearings ◽  
Multi Objective Optimization ◽  
Flexible Rotor ◽  
Weighting Method ◽  
Cross Sectional ◽  
Critical Speeds ◽  
Multi Objective ◽  
Design Variables ◽  
Single Objective

This paper presents the single objective optimization and the multi-objective optimization for a flexible rotor system with magnetic bearings. The weight of rotor shaft and the transmitted forces at the magnetic bearings are minimized either individually or simultaneously under the constraints on the critical speeds and the control currents of magnetic bearings. The design variables are the cross-sectional area of the shaft, the bias currents of magnetic bearings, and the positions of the disk and the magnetic bearings. The dynamic characteristics are analyzed using the generalized polynomial expansion method and the sensitivity analysis is also studied. For single objective optimization, the method of feasible directions (MFD) is applied. For multi-objective optimization, the weighting method (WM), the goal programming method (GPM), and the fuzzy method (FM) are employed. It is found that the system design can be significantly affected by the choices of the bias currents of magnetic bearings, the position of the disk with unbalance, and the magnetic bearings. The results also show that a better compromised design can always be obtained for multi-objective optimization.

Effect of Thrust Magnetic Bearing on Stability and Bifurcation of a Flexible Rotor Active Magnetic Bearing System

2003 ◽  
Vol 125 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Y. S. Ho ◽  
H. Liu ◽  
L. Yu
Keyword(s):  
Periodic Motion ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Flexible Rotor ◽  
Periodic Motions ◽  
Stability And Bifurcation ◽  
Mass Eccentricity ◽  
The Stability

This paper is concerned with the effect of a thrust active magnetic bearing (TAMB) on the stability and bifurcation of an active magnetic bearing rotor system (AMBRS). The shaft is flexible and modeled by using the finite element method that can take the effects of inertia and shear into consideration. The model is reduced by a component mode synthesis method, which can conveniently account for nonlinear magnetic forces and moments of the bearing. Then the system equations are obtained by combining the equations of the reduced mechanical system and the equations of the decentralized PID controllers. This study focuses on the influence of nonlinearities on the stability and bifurcation of T periodic motion of the AMBRS subjected to the influences of both journal and thrust active magnetic bearings and mass eccentricity simultaneously. In the stability analysis, only periodic motion is investigated. The periodic motions and their stability margins are obtained by using shooting method and path-following technique. The local stability and bifurcation behaviors of periodic motions are obtained by using Floquet theory. The results indicate that the TAMB and mass eccentricity have great influence on nonlinear stability and bifurcation of the T periodic motion of system, cause the spillover of system nonlinear dynamics and degradation of stability and bifurcation of T periodic motion. Therefore, sufficient attention should be paid to these factors in the analysis and design of a flexible rotor system equipped with both journal and thrust magnetic bearings in order to ensure system reliability.

scholarly journals Multiobjective Optimization of a Flexible Rotor in Magnetic Bearings With Critical Speeds and Control Current Constraints

1994 ◽  
Author(s):  
Ting Nung Shiau ◽  
Chun Pao Kuo ◽  
Jiunn Rong Hwang
Keyword(s):  
Expansion Method ◽  
Magnetic Bearings ◽  
Multi Objective Optimization ◽  
Flexible Rotor ◽  
Weighting Method ◽  
Cross Sectional ◽  
Critical Speeds ◽  
Multi Objective ◽  
Design Variables ◽  
Single Objective

This paper presents the single objective optimization and the multi-objective optimization for a flexible rotor system with magnetic bearings. The weight of rotor shaft and the transmitted forces at the magnetic bearings are minimized either individually or simultaneously under the constraints on the critical speeds and the control currents of magnetic bearings. The design variables are the cross-sectional area of the shaft, the bias currents of magnetic bearings, and the positions of the disk and the magnetic bearings. The dynamic characteristics are analyzed using the generalized polynomial expansion method and the sensitivity analysis is also studied. For single objective optimization, the method of feasible directions (MFD) is applied. For multi-objective optimization, the methods including the weighting method (WM), goal programming method (GPM), and the fuzzy method (FM) are employed. It is found that the system design can be significantly affected by the choices of the bias currents of magnetic bearings, the position of the disk with unbalance and the magnetic bearings. The results also show that a better compromized design can always be obtained for multi-objective optimization.

Sign in / Sign up

Export Citation Format

Share Document