Active Vibration Control of Distributed Systems Using Delayed Resonator With Acceleration Feedback

1997 ◽  
Vol 119 (3) ◽  
pp. 380-389 ◽  
Author(s):  
Nejat Olgac ◽  
Hakan Elmali ◽  
Martin Hosek ◽  
Mark Renzulli
Keyword(s):  
Primary Structure ◽  
Active Vibration Control ◽  
Experimental Tests ◽  
Dual Frequency ◽  
Vibration Absorption ◽  
Resonance Frequencies ◽  
Primary Body ◽  
Acceleration Feedback ◽  
Combined Structure ◽  
Active Vibration

The Delayed Resonator (DR) and Dual Frequency Fixed Delayed Resonator (DFFDR) are newly introduced control techniques for active vibration absorption. Both methods propose a delayed position feedback within the absorber section of the structure to impart ideal resonance features to the absorber. When installed on an oscillating primary body, they form “notch filters” at their resonance frequencies attenuating the response of the primary structure. The DR absorber is shown to be real-time tunable to time varying disturbance frequencies. In this article, a number of new issues are considered. First, the basic theory is modified for acceleration feedback instead of position, which was originally proposed for the DR methodology. Second, the new absorption methods are implemented on distributed parameter structures which are under high frequency excitation (around 1 KHz). Stability of the combined structure is studied on a reduced order multi-degree-of-freedom primary structure together with the DR absorber. Experimental tests are conducted on a steel beam to verify the analytical findings. Piezoelectric actuators are used both to generate harmonic disturbances and to implement the control. The correspondence observed between the theoretical and experimental results is encouraging. The efficiency of the DR and DFFDR absorption techniques is demonstrated.

Active Vibration Absorption Using Delayed Resonator With Relative Position Measurement

1995 ◽  
Author(s):  
Nejat Olgac ◽  
Martin Hosek
Keyword(s):  
Relative Position ◽  
Primary Structure ◽  
Vibration Suppression ◽  
Control Force ◽  
Range Analysis ◽  
Position Measurement ◽  
Harmonic Force ◽  
Stability Range ◽  
Vibration Absorption ◽  
Active Vibration

Abstract A novel active vibration absorption technique, the Delayed Resonator, has been introduced recently as a unique way of suppressing undesired oscillations. It suggests a control force on a mass-spring-damper absorber in the form of a proportional position feedback with a time delay. Its strengths consist of extremely simple implementation of the control algorithm, total vibration suppression of the primary structure against a harmonic force excitation and full effectiveness of the absorber in a semi-infinite range of disturbance frequency, achieved by real-time tuning. All this development work was done using the absolute displacements of the absorber in the feedback. These displacement measurements may be difficult to obtain and for some applications impossible. This paper deals with a substitute and easier measurement: the relative motion of the absorber with respect to the primary structure. Theoretical foundations for the Delayed Resonator (DR) are briefly recapitulated and its implementation on a single-degree-of-freedom primary structure disturbed by a harmonic force is introduced utilizing both absolute and relative position measurement of absorber mass. Methods for stability range analysis and transient behavior are presented. Properties acquired for the same system with these two different feedback are compared. Relative position measurement case is found to be more advantageous in most applications of the Delayed Resonator method.

Measurement of Critical Velocities for Fluidelastic Instability Using Vibration Control

2000 ◽  
Vol 122 (4) ◽  
pp. 341-345 ◽  
Author(s):  
S. Caillaud ◽  
E. de Langre ◽  
P. Piteau
Keyword(s):  
Vibration Control ◽  
Critical Velocity ◽  
Active Vibration Control ◽  
Cross Flow ◽  
Piezoelectric Actuators ◽  
Experimental Tests ◽  
Classical Stability ◽  
Fluidelastic Instability ◽  
Active Vibration ◽  
Critical Velocities

Fluidelastic effects may be responsible for instabilities of heat exchanger tubes when the fluid flow reaches the critical velocity. The fluidelastic phenomenon is usually studied on experimental mock-ups, which may display only one critical velocity. In this paper, a method based on active vibration control is proposed in order to derive several critical velocities for fluidelastic instability corresponding to several different values of damping, which is artificially varied on the same mock-up. Experimental tests are performed on a flexible tube equipped with piezoelectric actuators in a rigid array under air-water cross-flow. It is shown that the reduced critical velocities thus obtained fit well in a classical stability map. [S0739-3717(00)01603-2]

Active vibration control of rotor-bearing system by virtual dynamic absorber

2019 ◽  
Vol 86 (3) ◽  
pp. 30901
Author(s):  
Behnam Monjezi ◽  
Hamidreza Heidari
Keyword(s):  
Transient Response ◽  
Control Method ◽  
Active Vibration Control ◽  
Resonance State ◽  
Rotor System ◽  
Manufacturing Defects ◽  
Resonance Frequencies ◽  
Active Vibration ◽  
Dynamic Absorber ◽  
Rotor Dynamic

The main sources of the vibration in rotor dynamic systems are unbalanced masses and manufacturing defects of bearings used in the rotor system. In this study, magnetic absorber as a new method brings the rotor system out of resonance state by applying a dynamic absorber system force and creating two new natural frequencies. This study virtually reconstructed magnetic absorber controller software as a combined active and passive dynamic absorber to reduce vibration amplitude, efficiently. In this approach, combined routes are defined for the rotor frequency response, so that the optimal values of the parameters of dynamic absorber system are calculated using H∞ method and maximum damping for frequencies lower and higher than resonance frequencies, respectively. The results confirm that transient response overshoot is less, and transient response attenuation is more in maximum damping method. Hence, the controller system easily recognizes initial overshoots and determines the parameters of the dynamic absorber system in accordance with maximum damping state if it is struck at any rotor frequency and any rotation angle. It is also observed that for all rotor rotation frequencies, the system overshoot reduces in comparison with H∞ method by using this control method.

Model Based Simulation of the Active Damping of a Cantilever Plate and Redistribution of Stresses

2000 ◽  
Author(s):  
Sathya V. Hanagud ◽  
Patrick J. Roberts
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Closed Loop ◽  
Active Vibration Control ◽  
High Stress ◽  
Element Simulation ◽  
Control Scheme ◽  
Acceleration Feedback ◽  
Order Of Magnitude ◽  
Active Vibration

Abstract In most structures, fatigue critical areas are associated with regions of high stresses. Sometimes, passive stiffening of structures can displace these high stress regions. Thus, for most applications, active vibration control is preferred. However, the question of whether an active vibration control scheme involving a set of actuators will reduce stresses in the whole structure or create high stress areas in the vicinity of the actuators arises. In previous works, this question has been addressed for cantilever beams which showed that the stresses are reduced by approximately the same order of magnitude as the reduction in vibrations. However, many aerospace structures are constructed of thin walled components whose response to vibration reduction can be very different than that of beams. In this paper, the stresses induced by an active vibration control system, based on the use of an offset piezoceramic stack actuator with acceleration feedback control, are investigated in a plate structure. A 3-D finite element simulation of the closed loop active vibration control system is developed and both the closed loop stresses and vibration amplitude reductions are studied.

Low Frequency Micro-Vibration Active Isolation Control System Design and Experimental Research

2013 ◽  
Vol 482 ◽  
pp. 195-199 ◽  
Author(s):  
Shu Qing Li ◽  
Liang Liang Wang ◽  
Zhi Fei Tao
Keyword(s):  
Control System ◽  
Vibration Isolation ◽  
Active Vibration Control ◽  
Low Frequency ◽  
Experimental Tests ◽  
Seismic Exploration ◽  
Single Chip ◽  
Precision Equipment ◽  
Active Vibration ◽  
Micro Vibration

Whether in the aerospace, or seismic exploration, as well as high precision operation of all trades and professions, low-frequency interference directly influences the instrument monitoring and detection precision, resulting in insufficient accuracy of the implementing agencies. The passive vibration isolation method was used by most high accuracy equipment at present, the efficiency of isolation can only achieve 60%-70%, that will have influence to the extremely precision equipment certainly. In this paper an active vibration control system was realized by using single-chip microcomputer and the PID control algorithm. System simulation model was built and experimental tests had been conducted. The interference eliminated more than 80% for 3Hz and below,can effectively improve the precision equipment to work under the low frequency interference.The system provided an effective method to suppress the low frequency interference.

scholarly journals Experimental implementation of an artificial neural network-based active vibration control

2021 ◽  
Author(s):  
Yong Xia
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Vibration Control ◽  
Control Strategies ◽  
Active Vibration Control ◽  
Experimental System ◽  
Experimental Tests ◽  
Development Environment ◽  
Active Vibration ◽  
Artificial Neural

Vibration control strategies strive to reduce the effect of harmful vibrations on machinery and people. In general, these strategies are classified as passive or active. While passive vibration control techniques are generally less complex, there is a limit to their effectiveness. Active vibration control strategies, on the other hand, require more complex algorithms but can be very effective. In this current work, a novel active vibration control experimental system, including the hardware setup and software development environment, has been successfully implemented. A static artificial neural network-based active vibration control system has been designed and tested based on the experimental system. The artificial neural network is trained to model the plant using a backpropagation algorithm. After training, the network model is used as part of a feedforward controller. the efficiency of this controller is shown through experimental tests.

Active Damping by Acceleration Feedback Control and Redistribution of Stresses in the Structure

1999 ◽  
Author(s):  
Maxime P. Bayon de Noyer ◽  
Patrick J. Roberts ◽  
Sathya V. Hanagud
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Vibration Control ◽  
Closed Loop ◽  
Driving Forces ◽  
Active Vibration Control ◽  
High Stress ◽  
Low Frequency ◽  
Acceleration Feedback ◽  
Active Vibration

Abstract In most structures, fatigue critical areas are associated with regions of high stresses. Passive stiffening of structures usually displaces these high stress regions. Thus, for most applications, active vibration control is preferred. However, the question of whether an active vibration control scheme involving a set of actuators will reduce stresses in the whole structure or create high stress areas in the vicinity of the actuators arises. In this paper, the stresses induced by an active vibration control system based on the use of an offset piezoceramic stack actuator with acceleration feedback control are investigated. Using a modal analysis of the actuator acting on a cantilever beam, a low frequency approximation of the actuator is developed in the form of a spring and two driving forces. Based on this approximation, a 3-D finite element simulation of the closed loop active vibration control system is developed and the closed loop stresses are studied.

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