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.

Analysis on nonlinear stiffness and vibration isolation performance of scissor-like structure with full types

Abstract: Due to its simple structure and good deployable characteristics, scissor-like structure (SLS) is widely used in many fields, such as mechanical engineering, structure engineering, and aerospace engineering. Because of its inherent structural characteristics, a SLS can possess superior nonlinearities both in equivalent stiffness and damping only with linear component. It also has high loading capacity and excellent equilibrium stability. Thus, it is promising as a vibration isolator. Based on recent findings, a theoretical study is herein executed to build up a universal stiffness model of full types of SLS (including 6 assembly types), considering mass of scissor arm, Coulomb and viscous friction forces in joint parts. Plus more, perturbation method (PM) and average method (AM) are applied to investigate vibration isolation performances of SLS with different assembly types and installation parameters and to compare them with known quasi-zero-stiffness vibration isolators in the literature. Finally, a simulation is done to testify the presented findings and to compare them with former studies. It is shown that: without changing its overall structure and outside dimensions, a SLS vibration isolator can have significantly different nonlinear stiffness for specific nonlinear characteristics only through adjusting assembly type, installation parameters, and initial deformation of its linear component. Since allowable workspace of a vibration isolator is always limited by isolation object and its surrounding structure, this finding indicates a new way to design and modify vibration isolation performance of a system. It will greatly expand application of SLS in vibration isolation.

Active vibration control of structures undergoing bending vibrations

Abstract: An active vibration control subassembly for a structure (such as a jet engine duct or a washing machine panel) undergoing bending vibrations caused by a source (such as the clothes agitator of the washing machine) independent of the subassembly. A piezoceramic actuator plate is vibratable by an applied electric AC signal. The plate is connected to the structure such that vibrations in the plate induced by the AC signal cause canceling bending vibrations in the structure and such that the plate is compressively pre-stressed along the structure when the structure is free of any bending vibrations. The compressive prestressing increases the amplitude of the canceling bending vibrations before the critical tensile stress level of the plate is reached. Preferably, a positive electric DC bias is also applied to the plate in its poling direction.

Modeling and Control of Vibration in Mechanical Systems

Abstract: Many chapters have introductions, conclusions, and references Symbols and Acronyms 1 Mechanical Systems and Vibration Magnetic recording system Stewart platform Vibration sources and descriptions Types of vibration Random vibration Vibration analysis 2 Modeling of Disk Drive System and Its Vibration Introduction System description System modeling Vibration modeling Modeling of Stewart Platform System description and governing equations Modeling using adaptive filtering approach Classical Vibration Control Passive control Self-adapting systems Active vibration control Introduction to Optimal and Robust Control H2 and H norms H2 optimal control H control Robust control Controller parametrization Performance limitation Mixed H2/H Control Design for Vibration Rejection Mixed H2/H control problem Method 1: slack variable approach Method 2: an improved slack variable approach Application in servo loop design for hard disk drives Low-Hump Sensitivity Control Design for Hard Disk Drive Systems Problem statement Design in continuous-time domain Design in discrete-time domain Generalized KYP Lemma-Based Loop Shaping Control Design Problem description Generalized KYP lemma-based control design method Peak filter Application in high frequency vibration rejection Application in mid-frequency vibration rejection Combined H2 and KYP Lemma-Based Control Design Problem formulation Controller design for specific disturbance rejection and overall error minimization Simulation and implementation results Blending Control forMulti-Frequency Disturbance Rejection Control blending Control blending application in multi-frequency disturbance rejection Simulation and experimental results H -Based Design for Disturbance Observer Conventional disturbance observer A general form of disturbance observer Application results Two-DimensionalH2 Control for Error Minimization 2-D stabilization control 2-D H2 control SSTW process and modeling Feedforward compensation method 2-D control formulation for SSTW 2-D stabilization control for error propagation containment 2-D H2 control for error minimization Nonlinearity Compensation and Nonlinear Control Nonlinearity compensation Nonlinear control Quantization Effect on Vibration Rejection and Its Compensation Description of control system with quantizer Quantization effect on error rejection Compensation of quantization effect on error rejectioAdaptive Filtering Algorithms for Active Vibration Control Adaptive feedforward algorithm Adaptive feedback algorithm Comparison between feedforward and feedback controls Application in Stewart platform

High Bandwidth Tunability in a Smart Vibration Absorber

Abstract: An electrically tunable vibration absorber based on the strong ΔE effect of Terfenol-D has been developed. A general description of tuned vibration absorbers is presented along with a description of the magnetostrictive effects that make an electrically tunable Terfenol-D vibration aborber function. It is emphasized that the large modulus changes achievable with the proposed magnetostrictive vibration absorber arise as a consequence of the stiffening of the crystal lattice as the magnetic field is increased from the demagnetized state to magnetic saturation. This is in contrast to the small modulus changes often reported in the literature which are achieved by operating smart materials between their open- and short-circuit states. Experimental results are presented that show agreement with prior art and demonstrate control of a magnetostrictive actuator resonant frequency between 1375 Hz and 2010 Hz by electrically varying the elastic modulus of a magnetostrictive material. This operating principle is then implemented to obtain high bandwidth tunability in a Terfenol-D vibration absorber.