Multi-modal Vibration Control Research Articles

Distributed control of a plate platform by NES-cells

Nonlinear energy sink (NES) has become a good passive vibration control technique with great potential. For a huge structure, it is unpractical to control the vibration by just one NES, let alone the structure has multi-modes. In this work, a technique who uses distributed nonlinear energy sink cells (NES-cells) to control the multi-modal resonance of the floating raft is proposed. The floating raft is simplified as a corner-point supported plate. Natural modes of it guide the distribution of NES-cells to make NESs locate on the position with strong vibration, which enhances the coupling ship between the plate platform and NES-cells. An example of installing NES-cells guiding by the first-two modes of the corner-point supported plate is presented in this paper. It is compared with the vibration reduction effect by a single NES. To make a fair comparison, total mass of NES-cells is the same with that of the single NES. The results show that NES-cells can deal with multi-modal vibration reduction better. The experimental results also fully illustrate this view. At the same time, the reaction of each NES-cell to the plate is effectively dispersed while comparing with the single NES, which decreases the stress at the attachment points and is more suitable for engineering applications. The number of NES-cells also has an effect on the vibration reduction efficiency. When the design parameters are fixed, there exists an optimal number to make the vibration reduction efficiency tend toward saturation. The multimodal vibration control of the plate platform is effectively solved by the proposed NES-cells technique. It also provides guidance for other practical engineering problems.

Multi-modal vibration control for all-clamped plate subjected to periodic disturbances by ESO-based frequency-shaped LQR

Model uncertainties, external excitations and complex boundary conditions, etc. present in the control system lead to poor robustness of the controller. Therefore, an extended state observer (ESO) is utilized to compensate for these disturbances. However, a conventional ESO is not sufficiently capable to deal with rapid periodic disturbances. A frequency-shaped linear quadratic regulator (FSLQR) is, hence, developed by employing a frequency independent cost function according to the disturbance spectrum. In addition, knowing that periodic disturbances may have unknown or varying frequencies, a frequency-adaptive mechanism is introduced to address such issues, which enables the proposed method to mitigate the influences of frequency deviations. This is the first attempt to introduce frequency shaping technology into the control framework based on extended state observer. The control scheme of the introduced approach is general, but is conveyed here using solely an all-clamped plate structure with an inertial actuator, which is considered a typically benchmark for vibration phenomenon. The effectiveness and advantage of the proposed strategy are validated with comparative experimental studies on a hardware-in-the-loop laboratory testbed and a theoretical analysis based on Lyapunov theorem. Compared with the classical method based on ESO, the vibration experimental results demonstrate that the control performance of the first mode and the second mode are improved, both having upgraded approximately 6 dB.

Multimode vibration control of stay cables using pseudo negative stiffness MR damping system

At present the vibration control of stay cable suffers from low damping effectiveness in single mode vibration caused by the limitation of damper installation position as well as the poor modal compatibility, that is, a rapid degradation performance when the actual mode deviates from the designed optimal mode. In this paper, one practical semi-active magnetorheological (MR) damper based control solution is proposed to address the problems faced in multi-modal vibration control of stay cables. The semi-active pseudo negative stiffness (PNS) control strategy takes full account of the MR damper’s mechanical characteristics and the demands of the stay cable vibration control. Compared with the linear equivalent model, the proposed time-varying model exhibits more details of the damping force and the nonlinear response of the damped stay cable, which shows its essential role in the optimal design of MR-PNS scheme. Then the optimal design method of MR-PNS multi-modal vibration control for stay cable is summarized by taking the first three modes vibration control of the J20 cable in Nanjing Baguazhou Yangtze River Bridge as simulation examples. The simulations of cross-modal, multi-modal and wind-induced vibration cases are conducted respectively, while the results show that the optimal designed multi-modal MR-PNS scheme can simultaneously exceed the passive maximum modal damping ratio within first three modes. The advantages of the proposed MR-PNS method in high damping efficiency and modal compatibility could be verified by comparing with the passive multi-modal damping solution.

Multimodal vibration control with piezoelectric patches connected to self-tuning RLC shunts

This paper presents experimental results on the control of stochastic flexural vibrations in a plate equipped with five piezoelectric patches connected to self-tuning multi-resonant shunts composed by N-parallel resistive-inductive-capacitive (RLC) branches. The study contrasts the tuning of the branches based on the minimization of the time-averaged total flexural kinetic energy and the maximization of the time-averaged electric power absorbed by each RLC branch relative to the resonant responses of the target modes. Next, it investigates the online tuning of the branches RL components with an extremum seeking algorithm set to maximize the time-averaged electric power absorbed by each RLC branch.

Design of cylindrical metashells with piezoelectric materials and digital circuits for multi-modal vibration control

Thin-walled cylindrical shells are widely used in industries, such as the main parts of aircrafts, rockets, and submarines. Except for meeting the load-bearing capacities, such structures must also have good vibration and acoustic performances. However, it is still a challenge to control the multi-modal vibration of cylindrical shells at low frequencies. This study explores the cutting-edge local resonant piezoelectric metamaterials to control the low-frequency vibration of cylindrical shells. A novel cylindrical meta-shell with piezoelectric materials and digital circuits was proposed, and a multi-resonance transfer function is implemented in each digital circuit. A method to optimizing the parameters in the transfer function for the purpose of vibration reduction is developed. The vibrational characteristics of the meta-shell are numerically analyzed using the finite element method. Numerical results clearly demonstrate that by delicately designing the parameters in the transfer function, the meta-shell can reduce the peak amplitudes of the first five modes by 30 dB or more. Therefore, the proposed piezoelectric cylindrical meta-shell may open new opportunities in vibration mitigation of transport vehicles and underwater equipment.

A semi-active shunted piezoelectric tuned-mass-damper for multi-modal vibration control of large flexible structures

A semi-active electromechanical Tuned Mass Damper (SATMD), which consists of a combined spring-piezoelectric device connected to an external resistive-inductive electric circuit is presented, aiming to provide robust multi-modal vibration suppression capabilities in large flexible structures. The combined spring-piezoelectric device provides the stiffness for the resonant mass, and also electromechanical energy conversion and coupling. A reduced-ordered mode superposition structural dynamics model coupled with the SATMD device and the RL shunt electric circuit is formulated, to simulate the response of the integrated structural system. The broadband vibration reduction capabilities of the proposed SATMD are numerically and experimentally evaluated and quantified on a down-scaled simplified airframe model. Very good correlation between numerical and measured results is obtained. The results illustrate that a SATMD configuration with an auxiliary mass equal to 1% of the structural mass and combined resistive-inductive impedance, yields substantial simultaneous vibration suppression over the range of 3 low-frequency structural modes, and can be easily retuned to accommodate in-flight changes in structural and loading parameters.

Experimental modal identification of smart composite structure applied to active vibration control

This paper proposes an experimental modal identification method for vibration control of multi-actuators and multi-sensors complex smart structures. The general formulation avoids the difficulty of the coupling coefficients identification in electromechanical systems through a modal reduced-order model and uses first-order polynomials as phase correctors for the numerators of the identified transfer functions. Then, a frequency-shaped linear quadratic controller is designed to control multiple modes on a smart composite structure with integrated transducers. The experimental results obtained in terms of multi-modal vibration control were promising with attenuations up to 20 dB on the target modes, confirming the efficiency of the proposed identification and control method for future applications with more extended and complex composite smart structures.

Formula omitted] optimization of multiple tuned mass dampers for multimodal vibration control

In this paper, a new computational method for the purpose of multimodal vibration mitigation using multiple tuned mass dampers is proposed. Classically, the minimization of the maximum amplitude is carried out using direct H∞ optimization. However, as shall be shown in the paper, this approach is prone to being trapped in local minima, in view of the nonsmooth character of the problem at hand. This is why this paper presents an original alternative to this approach through norm-homotopy optimization. This approach, combined with an efficient technique to compute the structural response, is shown to outperform direct H∞ optimization in terms of speed and performance. Essentially, the outcome of the algorithm leads to the concept of all-equal-peak design for which all the controlled peaks are equal in amplitude. This unique design is new with respect to the existing body of knowledge.

Multi-modal Vibration Control of Truss Structures based on the Optimal Placement of a Sensor and an Actuator

Multi-modal Vibration Control of Truss Structures based on the Optimal Placement of a Sensor and an Actuator

A Controllability-Based TO Approach for the Piezoelectric Actuator Design Considering Multimodal Vibration Control

This paper addresses the design problem of piezoelectric actuators for multimodal active vibration control. The design process is carried out by a topology optimization procedure which aims at maximizing a control performance index written in terms of the controllability Gramian, which is a measure that describes the ability of the actuator to move the structure from an initial condition to a desired final state in a finite time interval. The main work contribution is that independent sets of design variables are associated with each modal controllability index, then the multi-objective problem can be split into independent single-objective problems. Thus, no weighting factors are required to be tuned to give each vibration mode a suitable relevance in the optimization problem. A material interpolation scheme based on the Solid Isotropic Material with Penalization (SIMP) and the Piezoelectric Material with Penalization (PEMAP) models is employed to consider the different sets of design variables and the sensitivity analysis is carried out analytically. Numerical examples are presented by considering the design and vibration control for a cantilever beam and a beam fixed at both ends to show the efficacy of the proposed formulation. The control performance of the optimized actuators is analyzed using a Linear-Quadratic Regulator (LQR) simulation.

Multi-mode optimal fuzzy active vibration control of composite beams laminated with photostrictive actuators

Firstly, a multi-field coupling finite element formulation of composited beam laminated with the photostrictive actuators is developed in this paper. Moreover, an optimal fuzzy active control algorithm is also proposed on the basis of the combination of optimal control and fuzzy one. This method opens a new avenue to resolve the contradiction between the linear system control method and nonlinear actuating characteristics of photostrictive actuators. The desired control for suppressing multi-modal vibration of photoelectric laminated beam is firstly obtained through optimal control and then the fuzzy control is used to approach the desired mechanical strain induced by photostrictive actuators. Thus, the multi-mode vibration control of beam is realized. In the design process of optimal fuzzy controller, the design of fuzzy control is independent of optimal control. The simulation results demonstrate that the proposed control method can effectively realize multi-modal vibration control of photoelectric laminated beams, and the control effect of optimal fuzzy control is better than that of optimal state feedback control.

Multi-modal Vibration Control of Laminated Plates based on the Optimal Placement of a Sensor/Actuator

Multi-modal Vibration Control of Laminated Plates based on the Optimal Placement of a Sensor/Actuator

Multimodal Vibration Control of Elastic Vibration of Railway Vehicle Carbody Using Active Mass Dampers

Multimodal Vibration Control of Elastic Vibration of Railway Vehicle Carbody Using Active Mass Dampers

Multi-Modal Active Vibration Control of a Lightweight Stress-Ribbon Footbridge Based on Subspace Identification

Abstract Experimental identification of the modal state-space model for Active Vibration Control (AVC) is proposed based on Subspace Identification Method (SIM). A stress-ribbon bridge built at the Technische Universitat Berlin was taken as research object. A real-time control system with pneumatic muscle actuators and inertial sensors was set up for AVC of the bridge. For the purpose of AVC, the feedback control design requires a modal state-space model, which describes the multi-modal characteristics of resonance modes of the bridge and the input/output relationship of the controlled system. Analytically, a state-space model of the bridge can be derived from Euler-Lagrange mechanism. However this is computationally expensive and the determination of damping ratios is also inconvenient. Comparably, SIM offers an attractive alternative due to simple and general parametrisation for Multiple-Input Multiple-Output (MIMO) systems. The identified state-space model from SIM can easily be transformed into a reduced modal state-space model for the AVC controller design. The goodness of the identified state-space model and the truncated modal state-space model was investigated in the stabilization diagram of SIM and with model fit indexes. The identified modal parameters of the footbridge from SIM were compared with that of previous free-vibration tests and the analytical model. Implementation of a Delayed Modal Velocity Feedback Control (DMVFC) based on the obtained modal state-space model was carried out for the full-scale lightweight bridge. The effectiveness of the proposed experimental identification method was shown in case of vertical resonance modes in vibration control experiments.

多モード制振を目的としたセンサ・アクチュエータ最適配置におけるトレードオフ分析

多モード制振を目的としたセンサ・アクチュエータ最適配置におけるトレードオフ分析

Modal Sensor Design based on Satisficing Trade-off Method and Its Application to Multi-modal Vibration Control

Modal Sensor Design based on Satisficing Trade-off Method and Its Application to Multi-modal Vibration Control

Accelerometer-based estimation and modal velocity feedback vibration control of a stress-ribbon bridge with pneumatic muscles

Lightweight footbridges are very elegant but also prone to vibration. By employing active vibration control, smart footbridges could accomplish not only the architectural concept but also the required serviceability and comfort. Inertial sensors such as accelerometers allow the estimation of nodal velocities and displacements. A Kalman filter together with a band-limited multiple Fourier linear combiner (BMFLC) is applied to enable a drift-free estimation of these signals for the quasi-periodic motion under pedestrian excitation without extra information from other kinds of auxiliary sensors. The modal velocities of the structure are determined by using a second Kalman filter with the known applied actuator forces as inputs and the estimated nodal displacement and velocities as measurements. The obtained multi-modal velocities are then used for feedback control. An ultra-lightweight stress-ribbon footbridge built in the Peter-Behrens- Halle at the Technische Universitat Berlin served as the research object. Using two inertial sensors in optimal points we can estimate the dominant modal characteristics of this bridge. Real-time implementation and evaluation results of the proposed estimator will be presented in comparison to signals derived from classical displacement encoders. The real-time estimated modal velocities were applied in a multi-modal velocity feedback vibration control scheme with lightweight pneumatic muscle actuators. Experimental results demonstrate the feasibility of using inertial sensors for active vibration control of lightweight footbridges.

Multi-modal vibration control of truss bridges with tuned mass dampers under general loading

Applications of tuned mass damper (TMD) systems for bridge structures are observed for mitigation of problem related to excessive vibration induced by either wind loading or vehicle loading, where dominant modes usually in one direction (commonly vertical) are taken into account. Considering modes dominant in one direction may not be considered as a robust practice while any bridge structure is having dominant modes along both the transverse and vertical directions and the same bridge structure is subjected to loading along both the directions. In the present study, an approach for simultaneous control of major horizontal, vertical and torsional modes is presented targeting robust vibration control under general loading condition. A strategy using modal frequency response function (FRF) is proposed based on the traditional mode-wise control approach. The proposed modal FRF based approach is applied to an existing important large truss bridge (Saraighat Bridge) to carry out an analytical design of TMD system considering general loading conditions. The designed TMD system is found to demonstrate good performance under various white-noise based general loading conditions.

Multimodal Vibration Control of Photo-Electric Laminated Thin Cylindrical Shells Via Self-Organizing Fuzzy Sliding Mode Control

In this paper, a novel multipiece actuator configuration is first proposed. This configuration exhibits several advantages over the existing ones, such as: (1) the ability to overcome the deficiency of one-way actuation of PbLaZrTi (PLZT) actuators and (2) all of the actuators in this configuration being placed on the inner surfaces of a thin cylindrical shell and the removal of extra electrical wires between the end surfaces of the actuators. A new index of modal control factors is defined, and an optimization method for allocating actuator is proposed. By using the proposed method, the PLZT actuators can be located in an optimum position. Moreover, in view of the nonlinear and time-variant characteristics of photostrictive actuators, a self-organizing fuzzy sliding mode control (SOFSMC) method is established to attenuate multimodal vibration of photo-electric laminated thin cylindrical shells. A multilevel sliding mode surface is defined as fuzzy input and the SOFSMC method is used to infer the applied light intensity. Its control rule bank can be developed and adjusted continuously via online learning. In addition, using fuzzy sliding mode, the chatter inherent in conventional sliding mode control is therefore managed effectively while ensuring sliding mode behavior. Case studies demonstrate that the proposed approach can efficiently suppress multimodal vibration of photo-electric laminated thin cylindrical shells. It is also founded that SOFSMC can achieve better control effect than fuzzy neural network control (FNNC).

Enhanced electromechanical coupling of piezoelectric system for multimodal vibration

An approach of enhancing the multimodal electromechanical coupling effect is proposed to improve the multimodal vibration control of piezoelectric systems. Theoretical research shows that when the electrode on the piezoelectric patch bonded on a vibrating structure is separated into several pieces, voltage response (including amplitude and phase) of each piece is different from each other. If each electrode is appropriately connected to the shunted circuit by certain design, the electromechanical coupling factor of the whole system can be increased effectively. In addition, the ‘current flowing circuit’ is introduced in the system to realize the multimodal vibration control. Experimental investigation has been carried out to validate the principle.