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 type motor device

Abstract: A vibration type motor device excites a vibration member by applying frequency signals to piezoelectric elements so as to obtain a driving force. A vibration state detection piezoelectric element is arranged on the vibration member, and when a vibration state is determined by detecting the phase difference between the output from the detection piezoelectric element and a driving frequency signal, a predetermined signal is superposed on the output from the detection piezoelectric element, thus allowing accurate detection of the vibration state even when the output from the piezoelectric element includes noise.

Active vibration control synthesis for the control of flexible structures mast flight system

Abstract: Pole-zero modeling and active vibration control synthesis for the Control of Flexible Structures Mast Flight System (COFS-I) are discussed. An analytical transfer function from the tip-mounted actuator force to the beam deflection at various sensor locations is derived for control synthesis. A new concept of generalized structural filtering for flexible-mode stabilization is applied to the COFS-I. The simplicity and practicality of the classical transfer-function approach to active structural vibration control are demonstrated for the COFS-I. In particular, nonminimum-phase structural filtering is proposed for the noncolocated control experiment of the COFS-I. The effects of proof-mass actuator dynamics and control-loop time delay on the phase/gain stabilization of the flexible modes are also discussed.

Method and apparatus for sensing and damping vibration

Abstract: A shape memory alloy used for both sensing and damping vibration of a structure. In one embodiment, a flat bar (12) is mounted from one end on its edge so that its other end vibrates from side-to-side at its natural resonant frequency. A vibration damping wire (30) extending longitudinally along one surface of the bar is mounted under tension between spaced apart standoffs (32); a sense wire (42) is similarly mounted along the opposite surface of the bar. The vibration damping wire and sense wire comprise a nickel-titanium (Nitinol) alloy, having a relatively high specific damping coefficient. Absorption of kinetic energy by the vibration damping wire when it is stretched by deflection of the bar greatly reduces the time required to passively damp vibration of the bar, compared to its undamped resonant time. the vibration damping wire is heated above a transition temperature by an electrical current pulse while relaxed to restore it to its unstretched length. The sense wire changes resistance in proportion to stress applied to the wire so that a voltage drop across the sense wire corresponds to the vibrational displacement of the bar. The voltage drop signal is used to control application of the current pulse in synchronization with the vibratory motion of the bar. To actively damp vibration of the bar, the pulse of electrical current is applied to heat the Nitinol alloy above its transition temperature so that it resumes a foreshortened memory shape as the bar's vibratory deflection tries to stretch the vibration damping wire. The vibration damping wire thus applies a force to the bar in opposition to its vibration. Other embodiments include a cylinder (52) and a vibration damped strut assembly (80). In these latter two embodiments, vibration damping wires and sense wires are disposed internally within the structure. A digital control (110) or analog vibration damping control (200) controls the application of current pulses to heat a selected vibration damping wire above the transition temperature in phase with the signal produced by the sensor wire.

Design of a Lightweight, Electrodynamic, Inertial Actuator with Integrated Velocity Sensor for Active Vibration Control of a Thin Lightly-Damped Panel

Abstract: This paper presents the design study of a lightweight inertial actuator, with integrated velocity sensor, for the implementation of velocity feedback control, i.e. active damping, in lightly-damped panels. The arrangement provides a collocated force actuator and velocity sensor device so that, in principle, an unconditionally stable direct velocity feedback loop could be implemented. However, this property is limited by the fundamental resonance due to the vibration of the inertial mass on the supporting spring. The main design issues are discussed starting from the characterization of the electromagnetic device which has been optimised using a Finite Element Analysis (FEA) to produce the maximum design force of 3N for a given weight of the inertial mass of 20g and input power constraints. The actuator suspension is designed so that important resonance frequencies lie outside the desired control bandwidth of 70Hz to 1kHz. Finally the design predictions are compared to measurements at a built up prototype actuator.