Active Vibration Suppression System Research Articles

An active piezoelectric damping vibration control system for the sting used in wind tunnel

In wind tunnel tests, the cantilever sting supporting system often suffers from low-frequency and large-amplitude resonance due to its inherent low structural damping characteristic, resulting in the degradation of data quality and structural safety. To improve wind tunnel testing safety and data accuracy, this paper is dedicated to establish an active vibration control system using piezoelectric stack actuators. A novel methodology of vibration monitoring based on modal transformation, which uses measured strain and a Strain-to-Displacement Transformation (SDT) matrix to reconstruct dynamic displacement field, is proposed herein. Meanwhile, strain sensor positions are optimized by an improved Particle Swarm Optimization (PSO) algorithm to reduce systematic estimation errors of this method. Furthermore, a Back-Propagated Neutral Network (BPNN) is established to implement a self-adaptive control strategy. A series of verification tests are performed to demonstrate the validity of the proposed system. Experimental results indicate that the relative Root Mean Square Error (RMSE) between estimated vibration displacement and measured vibration displacement is less than 3%, and a vibration attenuation of over 14 dB/Hz is achieved in ground tests, proving the superiority of this intelligent active vibration suppression system.

Characterization of piezoelectric patch material with hysteresis, saturation, creep, and vibration nonlinearity effects and its application to the active vibration suppression for cantilever beam

This research work aims to investigate the presence of four nonlinear characteristics (i.e., hysteresis, saturation, creep, and uncertainty vibration) when a piezoelectric patch material acts as an actuator and sensor for the active vibration suppression of a cantilever beam. The parameters such as different operating frequencies and voltages are taken into account for the piezoelectric patch material characterization and the vibration before and after activation of a proportional–derivative–integral controller in an active vibration suppression system are measured. The effect of different proportional–derivative–integral controller tuning methods, frequency independent, and frequency dependency excitations are the three main contributions to evaluate the performance of active vibration suppression system. From the results, the piezoelectric actuator posed all the four nonlinearity effects while only three are observed in the sensor characteristics, and these effects increased significantly with the increase of operating frequencies and voltages. For the frequency-independent excitation of the active vibration suppression system, the vibration attenuation of the beam shows an improvement from low to higher excitation frequency, except at 500 Hz because of the saturation effect. In terms of controller performances, the proportional gain step-up method shows the best performance by scoring 3/5 of highest vibration attenuation percentages compared with manual and Ziegler–Nichols methods. For the frequency-dependent excitation, the effective frequency range for the active vibration suppression system is determined between 75 and 245 Hz with the highest vibration attenuation of 79.60% occurred at the second natural frequency of the beam.

Линии тока и вектор плотности потока энергии при возбуждении колебаний пьезоэлектрическим преобразователем в слоистом фононном кристалле

The use of periodic composite structures has a great potential for improving sensors/actuators and self-adjusting optics, as well as for active vibration suppression and energy storage systems. At the same time, the employment of dielectric elastomers offers even greater possibilities since they provide tools for the active control of wave energy fluxes. The mathematical formulation of the problem considers more general state equations for piezoelectric bodies. Namely, the absence of symmetry in elastic and piezoelectric tensors is taken into account. The present study investigates the features of elastic wave excitation by a surface piezoelectric transducer (generally made of dielectric elastomer) in multi-layered periodic composites or so-called phononic crystals. A hybrid approach is used to solve the boundary value problem, which involves application of the spectral element method and the boundary integral equation method. Employing the energy streamlines and the power density vector, wave phenomena associated with the interaction of a piezoelectric transducer with a layered phononic crystal at frequencies belonging to four frequency ranges (band gaps, pass bands and the frequency ranges, in which only a quasi-transverse or quasi-longitudinal waves propagate without attenuation) are analyzed.

An active control strategy to suppress nonlinear vibrations of large space membranes

Large space membranes have been widely used in many space projects to develop extremely large and lightweight SAR antennas, solar arrays and solar sails, and the nonlinear structural vibrations induced by on-orbit disturbances should be suppressed to satisfy the mission requirements. In this paper, the nonlinear dynamic behaviors of a typical large space membrane, which can not be accurately described by natural frequencies and mode shapes, are investigated by the trustworthy iterative membrane property modeling approach. Based on the discussions of the controller design challenges from such nonlinearity, this paper proposes a distributed control strategy to actively suppress the nonlinear membrane vibration, and comparatively evaluates three different actuating and sensing placements to obtain superior vibration suppression performance. Very promising results numerically demonstrate that the proposed control strategy is theoretically feasible and has great potential to be used in the design of active vibration suppression systems for large space membrane applications.

Embedded explicit model predictive vibration control

This article presents an embedded active vibration suppression system featuring real-time explicit model predictive control (EMPC) that is implemented on a microcontroller unit (MCU). The EMPC controller minimizes the tip deflection of an aluminum cantilever beam driven by piezoceramic actuators, gaining its feedback from direct position measurements. The output and input performance of the EMPC method is compared to an analogously tuned positive position feedback (PPF) controller. An extensive analysis is provided on the cycle timing and memory needs of the explicit predictive vibration control scheme. The results demonstrate that the EMPC controller may achieve the same vibration suppression results compared to PPF with less input effort, while inherently respecting process constraints. Furthermore, we show that EMPC task execution timing is comparable in the random access memory (RAM) and read only memory (ROM) alternatives, suggesting that numerous current microcontrollers are suitable for EMPC-based active vibration control, in case the prediction model is kept simple.

A review of active vibration and noise suppression of plate-like structures with piezoelectric transducers

Structural vibrations are the major causes of noise problems, passenger discomforts, and mechanical failures in aerospace, automotive, and marine systems, which are mainly composed of lightweight and flexible plate-like structures. In order to reduce structural vibrations and noise radiations of lightweight structures, passive and active treatments have been used and investigated over the last three decades. Our aim of this article is to review current state-of-the-art of active vibration and noise suppression systems for plate and plate-like structures with various kinds of boundary conditions. The reviewed articles use numerical methods and experimental tools to study different aspects of controller architectures. In particular, the focus is placed on the active vibration and noise control systems utilizing piezoelectric patches as sensors and actuators since their popularity in vibration-based applications has increased significantly during the last two decades. We first classify the controllers according to their architectures, then compare their performance in vibration and noise attenuation, and finally provide suggestions for further progress. The categorization of the information regarding the controller strategies and sensor/actuator configurations for different host structures can be used by the controller designers as a starting point for their specific configuration.

Adaptive regulation—Rejection of unknown multiple narrow band disturbances (a review on algorithms and applications)

The paper addresses the problem of attenuation (rejection) of unknown and time varying multiple narrow band disturbances without measuring them. In this context the disturbance model is unknown and time varying while the model of the plant is known (obtained by system identification) and almost invariant. This requires to use an adaptive feedback approach. The term “adaptive regulation” has been coined to characterize this control paradigm. Application domains include: mechanical and mechatronics systems, active vibration and noise suppression systems, some types of bio-chemical reactors. The paper reviews the various techniques proposed for solving this problem. It will focus on the presentation of the direct and indirect adaptive regulation strategies using the internal model principle and the Youla–Kucera parametrization which have been extensively used in applications. The paper also reviews a number of applications including: active suspension systems, active vibration control systems, active noise control, bio-chemical reactors, distributed flexible mechanical structures and Blu-ray disc drives. Real time results obtained on various applications will illustrate the methodology.

Use of Lightweight Piezo-composite Actuators to Suppress the Free Vibration of an Aluminum Beam

A lightweight piezo-composite actuator (LIPCA) is used to suppress the vibration of an aluminum beam. Composed of a piezoelectric layer, a carbon-epoxy layer, and glass-epoxy layers, the LIPCA has better performance and durability than bare piezoelectric ceramics (PZT). This study estimates the actuation performances of a LIPCA in an active vibration control as well as a static actuation test. Experiments are performed on an aluminum beam in a cantilever configuration. The LIPCA, a bare PZT, and a 3GE+PZT actuator are attached to the aluminum beam with adhesive in order to investigate their performance. A comparison of the equivalent actuation moment and the tip deflection of the beam between the LIPCA, the bare PZT, and the 3GE + PZT actuator shows that the LIPCA has a better actuation performance than the bare PZT and the 3GE + PZT actuator. In addition, a digital PID control algorithm is applied to the active vibration control system to show how the LIPCA performs as an actuator in an active vibration suppression system. The results show that the LIPCA can effectively suppress free vibration of the aluminum beam, compared to the bare PZT and the 3GE + PZT actuator. The experiment confirms that the LIPCA can be used as an actuator to suppress vibration of dynamic structures.

Vibration control of beams using multiobjective state-feedback control

An active vibration suppression system is designed using a multiobjective state-feedbackcontroller. The governing equation of motion for a piezo/beam system is derived usingHamilton’s principle. The control gains of the resulting system are selected using the theoryof robust controls. In this regard, a robust controller is designed using a feedback control law that satisfies additional constraints on the closed-loop pole locationin the face of model uncertainties, which are derived for a general class of convexregions of the complex plane. These constraints are expressed in terms of thelinear matrix inequalities approach for multiobjective synthesis. The validity andapplicability of this approach for vibration suppression for the piezo/beam systemby damping out the multiple vibrational modes of the piezo/beam system arediscussed.

Active Vibration Suppression of Sandwich Beams using Piezoelectric Shear Actuators: Experiments and Numerical Simulations

This article deals with the experimental and numerical assessment of the vibration suppression of smart structures using piezoelectric shear actuators. Experimental results are presented for an adaptive sandwich cantilever beam that consists of aluminum facings and a core composed of two piezoelectric shear actuators and foam. The electric field is applied perpendicular to the poling direction of the piezoelectric actuators to cause transverse shear deformation of the sandwich beam. Active vibration suppression is achieved using either positive position feedback or strain rate feedback. The control system is implemented in real-time using Matlab/Simulink and a dSPACE digital controller. First, the frequency response of the adaptive beam is investigated by using one shear actuator to excite the beam and the other to control its vibration. Parametric studies are conducted to assess the influence of controller parameters on the frequency response of the system. The experimental frequency response function compares well with numerical simulations using the finite element method. Next, the effectiveness of the active vibration suppression system in the time domain is analyzed using a proof-mass actuator that is attached to the tip of the cantilever beam to provide a repeatable vibration input. Experiments and numerical simulations show that the shear actuators can provide significant reduction in tip acceleration and settling time.

Global control of a vibrating plate using a feedback-controlled inertial actuator

Strategies for the suppression of plate vibration are investigated by considering approximations to the equivalent impedance of power-minimizing vibration controllers. The total power transmitted to a plate by both a primary and a secondary point force is minimized and the equivalent impedance presented by the secondary source to the plate is considered. A novel device for active vibration control, based on an inertial actuator with displacement sensor and local PID controller and an outer velocity feedback control loop, is used to control the vibrating flexible plate. The impedance presented to the plate by this actuator is compared with the equivalent impedance of the optimal active control system. A frequency-domain formulation is used to analyse the stability and performance of an active vibration suppression system using this modified inertial actuator. The results of an experimental study of active vibration suppression on a flexible plate using the modified inertial actuator are then described. Theory and experiments agree well, demonstrating the effectiveness of the modified inertial actuator.

Vibration Suppression System Design for Multidegree of Freedom System using Closed Loop System Redesign.

This paper aims at proposing a new design method of active/ passive hybrid type of vibration suppression system for reducing the dynamic response of multi-story structures due to earthquake or other dynamic loads. Proposed new design method of hybrid vibration suppression system is based on closed loop system redesign which was proposed by the authors. Optimum design problem is formulated for the multi-story structure equipped with an active mass damper and oil dampers. The objective function is a linear combination of the evaluation of control power requirement of the active mass damper and the vibration suppression performance index of oil dampers. Availability of the proposed design method is numerically and experimentally demonstrated. Hybrid vibration suppression system for two-story structure is successfully designed by using proposed design method. Both numerical and experimental results indicate that hybrid vibration suppression system is effective comparing with full active vibration suppression system from the viewpoint of the active control power requirement under the equal vibration suppression performance codition.

Application of Internal Model Based Controller to Active Vibration Suppression System

More and more attention has been attracted to active vibration control with intelligent materials such as piezoelectric materials, etc. This paper deals with the problem of active vibration control of mechanisms. An internal model based controller is suited for regulation problems with periodic disturbance or tracking problems with periodic input. It has the ability to reject periodic disturbances, at the same time it is robust to parameter perturbation. In this paper an internal model principle is introduced, and simulations are carried out to show its features. In addition, the control strategy is implemented for active vibration suppression of a flexible four bar linkage bonded with piezoelectric materials as sensors and actuators. When the mechanism rotates, periodic inertial forces serve as a disturbance to induce vibration along the flexible coupler. The purpose of the experiment is to suppress this vibration using a piezoelectric actuator. The experimental system is built up with computer, A/D and D/A converter, piezoelectric sensor and actuator, low-pass filter, voltage amplifier and charge amplifier. Encouraging results are gained when the strategy is implemented in the experiments.

Active Vibration Control Using NiTiNOL and Piezoelectric Ceramics

The results of a study recently completed by Boeing Aerospace & Elec tronics to investigate the use of NiTiNOL Shape Memory Metals as the sensor and actua tor components of active vibration suppression systems are presented. Two different test set-ups consisting of aluminum cantilever beams with NiTiNOL wires fastened along both sides were developed. The test article for the first set-up was a very flexible, low frequency beam which utilized NiTiNOL wires for both sensing and actuation. The test article for the second set-up was a much stiffer, high frequency beam which utilized NiTiNOL wires for sensing and piezoelectric ceramics for actuation. The settling times of both beams were significantly reduced through the use of the NiTiNOL wire sensors and actuators. Analytical simulations were developed which correlated well with the experimental results. The results of the study demonstrated the feasibility of using NiTiNOL sensors and actuators for active vibration control of structural members.