Closed-Loop Vibration Control of Flexible Rotors—An Experimental Study

1993 ◽  
Vol 207 (1) ◽  
pp. 1-17 ◽  
Author(s):  
C R Burrows ◽  
P S Keogh ◽  
R Tasaltin
Keyword(s):  
Experimental Study ◽  
Vibration Control ◽  
State Feedback ◽  
Closed Loop ◽  
Dominant Mode ◽  
Pole Placement ◽  
Magnetic Actuator ◽  
Flexible Rotors ◽  
Measured Displacement ◽  
Control Forces

An experimental study has been made for the synchronous vibration control of a rotor-bearing system using a magnetic actuator to supply the control forces. Both open- and closed-loop strategies were implemented using measured displacement signals from various transducer configurations. Model reduction based on dominant mode methods was used to aid the design of the closed-loop strategies. These were based on pole placement techniques. It was shown that state feedback, without co-location of sensors and actuator, can be used to suppress critical speed responses without encountering spillover problems. The robustness of the strategies was also assessed by deleting selected feedback paths.

Optimized Design of Vibration Controllers for Steady and Transient Excitation of Flexible Rotors

1995 ◽  
Vol 209 (3) ◽  
pp. 155-168 ◽  
Author(s):  
P S Keogh ◽  
C Mu ◽  
C R Burrows
Keyword(s):  
Measurement Error ◽  
Controller Design ◽  
Optimized Design ◽  
Rotor Vibration ◽  
Transient Vibration ◽  
Flexible Rotors ◽  
Vibration Attenuation ◽  
Measured Displacement ◽  
Control Forces ◽  
Shaft Surface

Controller designs for the attenuation of rotor vibration are investigated. Disturbance inputs leading to vibration are classified and related to control forces and defined control states. Optimization based on the H∞ norm is then used to minimize the influence of forcing disturbances, modelling error and measurement error. The practicalities of applying the method to an experimental rotor-bearing system, with hardware constraints on controller order, are stated. The controller was implemented experimentally to conduct steady state and mass loss tests. Steady synchronous, non-synchronous and transient vibration attenuation was demonstrated. It was also shown that measurement error, caused by shaft surface roughness, can be incorporated into the controller design without the need to remove the roughness component from the measured displacement signals. If the roughness influence is not included in the design and the uncontrolled vibration is small, unnecessary control forces may result, causing an increase in vibration.

scholarly journals Performance of an Electromagnetic Bearing for the Vibration Control of a Supercritical Shaft

1987 ◽  
Vol 201 (3) ◽  
pp. 201-212 ◽  
Author(s):  
C D Bradfield ◽  
J B Roberts ◽  
R Karunendiran
Keyword(s):  
Vibration Control ◽  
Control Algorithm ◽  
Control Strategies ◽  
Single Point ◽  
Test Rig ◽  
Rotating Shaft ◽  
Linear Spring ◽  
Measured Displacement ◽  
Control Forces ◽  
Electromagnetic Bearing

The flexural vibrations of a rotating shaft, running through one or more critical speeds, can be reduced to an acceptably low level by applying suitable control forces at an intermediate span position. If electromagnets are used to produce the control forces then it is possible to implement a wide variety of control strategies. A test rig is described which includes a microprocessor-based controller, in which such strategies can be realized in terms of software-based algorithms. The electromagnet configuration and the method of stabilizing the electromagnet force–gap characteristic are discussed. The bounds on the performance of the system are defined. A simple control algorithm is outlined, where the control forces are proportional to the measured displacement and velocity at a single point on the shaft span; in this case the electromagnet behaves in a similar manner to that of a parallel combination of a linear spring and damper. Experimental and predicted performances of the system are compared, for this type of control, where various programmable rates of damping are applied.

Piezoelectric Devices for Vibration Control on Flexible Structures

1991 ◽  
Author(s):  
I. Legrain ◽  
P. Destuynder
Keyword(s):  
Experimental Study ◽  
Vibration Control ◽  
Closed Loop ◽  
Flexible Structures ◽  
Vibration Modes ◽  
Piezoelectric Devices

Abstract A coupled numerical and experimental study, concerning the vibration control, on flexible structures by piezoelectric devices, is presented in this paper. More precisely we studied two cases of structure, a beam and a plate, in several configurations of excitation. The implemented controls, which are closed loop controls, concern always the first vibration modes.

A New Method of Calculating the State Feedback Gain Vector of Vibration Control System

2012 ◽  
Vol 229-231 ◽  
pp. 424-427
Author(s):  
Ming Yang ◽  
De Chen Zhang ◽  
Xin Xiang Zhou
Keyword(s):  
Vibration Control ◽  
Uncertain Systems ◽  
State Feedback ◽  
Closed Loop ◽  
Random Perturbation ◽  
Feedback Gain ◽  
Uncertain Parameters ◽  
Vibration System ◽  
Deterministic Systems ◽  
Closed Loop Systems

Using the random model, the vibration control problem of structures with uncertain parameters is discussed, which is approximated by a deterministic one. The feedback gain matrix is determined based on the deterministic systems, and then it is applied to the actual uncertain systems. A method to calculate the standard deviations for responses of the closed-loop systems with the uncertain parameters is presented by using the random perturbation. This method is applied to a vibration system to illustrate the application. The numerical results show that the present method is effective.

Pole Placement Techniques for Active Vibration Control of Smart Structures: A Feasibility Study

2007 ◽  
Vol 129 (5) ◽  
pp. 601-615 ◽  
Author(s):  
Rajiv Kumar ◽  
Moinuddin Khan
Keyword(s):  
Vibration Control ◽  
Closed Loop ◽  
Smart Structures ◽  
Active Vibration Control ◽  
Control Design ◽  
Pole Placement ◽  
Parametric Uncertainties ◽  
Robust Performance ◽  
System Parameters ◽  
Active Vibration

It is well known that there is degradation in the performance of a fixed parameter controller when the system parameters are subjected to a change. Conventional controllers can become even unstable, with these parametric uncertainties. This problem can be avoided by using robust and adaptive control design techniques. However, to obtain robust performance, it is desirable that the closed-loop poles of the perturbed structural system remain at prespecified locations for a range of system parameters. With the aim to obtain robust performance by manipulating the closed loop poles of the perturbed system, feasibility of the pole placement based controller design techniques is checked for active vibration control applications. The controllers based on the adaptive and robust pole placement method are implemented on smart structures. It was observed that the adaptive pole placement controllers are noise tolerant, but require high actuator voltages to maintain stability. However, robust pole placement controllers require comparatively small amplitude of control voltage to maintain stability, but are noise sensitive. It was realized that by using these techniques, robust stability and performance can be obtained for a moderate range of parametric uncertainties. However, the position of closed-loop poles should be judiciously chosen for both the control design strategies to maintain stability.

A Programmable Electromagnetic Bearing for Vibration Control of a Flexible Shaft

1991 ◽  
Vol 113 (2) ◽  
pp. 160-166 ◽  
Author(s):  
C. D. Bradfield ◽  
J. B. Roberts ◽  
S. Karunendiran
Keyword(s):  
Vibration Control ◽  
Control Strategy ◽  
Stiffness Coefficient ◽  
Test Rig ◽  
Microprocessor Control ◽  
Transverse Vibrations ◽  
Flexible Rotors ◽  
Theoretical Predictions ◽  
Control Forces ◽  
Electromagnetic Bearing

The transverse vibrations of flexible rotors can be reduced to safe levels by radial control forces at an intermediate span position, applied by a suitable actuator. One versatile control strategy applies forces proportional to displacement and velocity, with coefficients dependent on the rotational speed. This control can be realized with an electromagnetic bearing under microprocessor control. Suitable microprocessor software is described, to implement the required real-time computation of the control forces. Experimental results obtained from a test rig are compared with theoretical predictions. There are advantages in allowing the stiffness coefficient to become negative, provided that positive damping is simultaneously applied.

A simulation apparatus for the experimental study of batch reactor control methods

1986 ◽  
Vol 51 (6) ◽  
pp. 1259-1267
Author(s):  
Josef Horák ◽  
Petr Beránek
Keyword(s):  
Experimental Study ◽  
Closed Loop ◽  
Dynamic Properties ◽  
Batch Reactor ◽  
Exothermic Reaction ◽  
Electric Heating ◽  
Batch Reactors ◽  
Exchange Area ◽  
The Stability ◽  
Methods Of Control

A simulation apparatus for the experimental study of the methods of control of batch reactors is devised. In this apparatus, the production of heat by an exothermic reaction is replaced by electric heating controlled by a computer in a closed loop; the reactor is cooled with an external cooler whose dynamic properties can be varied while keeping the heat exchange area constant. The effect of the cooler geometry on its dynamic properties is investigated and the effect of the cooler inertia on the stability and safety of the on-off temperature control in the unstable pseudostationary state is examined.

scholarly journals Experimental study on seismic vibration control of stockers in wafer and LCD panel fabs

Structures ◽  
2021 ◽  
Vol 31 ◽  
pp. 1185-1198
Author(s):  
Yung-Tsang Chen ◽  
Chien-Liang Lee ◽  
Miao-Chi Wang ◽  
Yen-Po Wang
Keyword(s):  
Experimental Study ◽  
Vibration Control ◽  
Seismic Vibration
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