Active vibration control

About: Active vibration control is a research topic. Over the lifetime, 6770 publications have been published within this topic receiving 76599 citations. The topic is also known as: active vibration damping.

Vibration absorber for reduction of the in-plane vibration in an optical disk drive

Abstract: A new type of vibration absorber is developed to reduce the in-plane vibration of the feeding deck system in an optical disk drive. In order to derive the equations of motion for the feeding deck system with the absorbers, a vibration model is established. After the frequency response function is obtained from the equations, the effects of absorber mass, stiffness and damping are analyzed. The material properties and shape of the vibration absorber are determined from the analysis results. For the purpose of verification, the performance of the absorber is investigated through experiments. The test results show that the proposed absorber is able to considerably reduce vibration in a wide range of spindle motor speeds.

Finite element analysis of actively controlled smart plate with patched actuators and sensors

Abstract: The active vibration control of smart plate equipped with patched piezoelectric sensors and actuators is presented in this study. An equivalent single layer third order shear deformation theory is employed to model the kinematics of the plate and to obtain the shear strains. The governing equations of motion are derived using extended Hamilton's principle. Linear variation of electric potential across the piezoelectric layers in thickness direction is considered. The electrical variable is discretized by Lagrange interpolation function considering two-noded line element. Undamped natural frequencies and the corresponding mode shapes are obtained by solving the eigen value problem with and without electromechanical coupling. The finite element model in nodal variables are transformed into modal model and then recast into state space. The dynamic model is reduced for further analysis using Hankel norm for designing the controller. The optimal control technique is used to control the vibration of the plate.

Active Vibration Control of a Flexible Rotor on Flexibly-Mounted Journal Bearings

Abstract: Some recent experimental studies have been concerned with the stabilization of rotating machinery through control action applied at critical points on the rotor. These studies have tended to ignore fundamental constraints on the positioning of active control inputs and measurement transducers. Such constraints must be considered to ensure both a cost effective design and system integrity in the event of component failure. This paper presents the first stage of a theoretical examination of active control by investigating a mathematical model of a three-mass flexible rotor symmetrically supported on flexibly mounted journal bearings. Three questions are posed: how many control sources are required, what measurement transducers are required and what information about the system dynamics is required in order to implement active control? The multivariable nature of the model and uncertainty about the oil-film dynamics makes general solutions to these problems difficult. However some solutions are proposed based upon the structural properties of the model. It is shown that the general requirements for system identification and control are conflicting. The practical implications of this conflict are discussed.

Active vibration suppression apparatus, control method therefor, and exposure apparatus having active vibration suppression apparatus

Abstract: In precision equipment such as a semiconductor exposure apparatus, an inertial load is driven by using an actuator, and an actuator fixed to a structure such as a vibration isolation base, an apparatus mounted on the base, and a control force is applied to the structure by using a drive reaction force generated upon driving of the inertial load, thereby stably and quickly suppressing produced vibrations.