Semi-active Vibration Suppression Research Articles

Magnetostrictive Vibration Suppression via Integration of Current Amplification Negative Capacitor and Current Inversion Semi-Active Control Circuit

When attempting to suppress structural vibrations employing a magnetostrictive transducer, owing to the control force is generated from current, a larger amplification of the current entails superior control performance. The semi-active control theory uses the synchronized switching damping (SSD) technique for structural vibration suppression while requiring a minimal energy supply. However, the absence of external energy input limits the current amplification performance. To address this limitation, this study proposes a novel method that combines semi-active vibration suppression method with negative capacitance to improve the current amplification performance. The proposed circuit switches the circuit status between shunt, inductor-capacitor (LC) electrical oscillation, and negative capacitance circuits. A mathematical model was employed to analyze the current operation, suppression performance, and robustness of the proposed circuit. Further, machine learning and kernel regression model were employed to predict the optimal control force gain. Validation experiments conducted on a 10-bay truss structure identical to the simulation model show that the experimental results align with the simulation predictions. The vibration suppression rates of the proposed method under single-mode and multiple-mode vibrations reached 85.8% and 78.3%, respectively, which are 2.64 and 1.89 times higher than those achieved by conventional methods.

Magnetostrictive-based induced current inversion and amplification: Semi-active vibration suppression for multiple-degree-of-freedom flexible structures

Vibration suppression technology is indispensable in the operation of multiple-degree-of-freedom (MDOF) structures. Properties such as a light weight and reliability are essential for an MDOF structure. However, truss structures tend to be flexible and susceptible to vibration from external influences. Hence, vibration suppression for MDOF flexible structures is necessary. This paper proposes a new semi-active vibration suppression method with a magnetostrictive transducer that can be applied to vibration suppression of an MDOF flexible structure. The proposed method is achieved through an electrical control circuit consisting a magnetostrictive transducer, an inversion capacitor, an electronic switch, and diodes. The control input of the proposed method is considered the induced current. With strategic selection of the circuit statuses, the amplitude of the induced current can be inversed and amplified. Our proposed control strategy is to control the circuit statuses so that the vibration suppression performance can be as effective as possible. The control strategy is determined based on the vibration displacement and velocity of the structure. Numerical simulations were performed to predict the vibration suppression performance. Subsequently, validation experiments were performed using a vibrating cantilevered truss structure, which was considered an MDOF structure composed of many aluminum bar members and iron joints. Under various experimental conditions, the proposed method achieved suppression rates of 12.1–26.7%. The results validated that the proposed method is more effective than a conventional passive method for the vibration suppression of an MDOF flexible structure. The proposed method may aid in ensuring the safe operation of MDOF flexible structures, such as trusses, under extreme conditions.

Tunable energy harvesting vibration absorber with liquid-metal filled elastic chamber

This paper presents a novel tunable energy harvesting vibration absorber with liquid-metal filled elastic chamber (TEHVA-LMEC) for simultaneously achieving tuned energy harvesting and semi-active vibration suppression. This device consists of a rigid chamber covered with two rubber membranes, two parallel magnets, copper bar electrodes, and liquid metal filled inside the chamber. Liquid metal functions both as the core component for electromagnetic energy harvest, i.e. cutting the magnetic induction lines and producing electricity, and in the meantime provides inertia as liquid mass for vibration suppression. Therefore, TEHVA-LMEC inherits the advantages of both liquid-mass tuned vibration absorbers (TVAs) and electromagnetic energy harvesters, including weight efficiency, simpler tuning procedure, and larger power output with lower internal impedance. More importantly, the natural frequency and the optimal energy harvesting frequency of TEHVA-LMEC are adjusted synchronously, which is beneficial in engineering applications where external excitation and the primary structure’s dynamic characteristics are not constant. A single-degree-of-freedom (SDOF) analytical model of TEHVA-LMEC is proposed for the discussions of its output voltage and natural frequency. A parameter investigation reveals that the rated output voltage can be designed by adjusting two design parameters. A prototype based on the analytical model is tested on an electrodynamic shaker. Experiments evaluated the electromagnetic energy harvesting function and its characteristic with different vibrating frequencies. Both tuned energy harvesting and vibration absorption functions of TEHVA-LMEC are verified.

A simple and novel control strategy for semi-active vibration suppression by a magnetorheological damper

Conventional skyhook-based ON–OFF control switches the damping force on a vibration suppression target according to the sign of the product of the target and relative velocities (which is called the condition function). Here, we propose a control strategy that uses a novel condition function for improved performance. The proposed strategy is formulated based on the theory of forced vibration with base excitation. Its effect upon semi-active vibration performance is investigated via numerical simulations and experimental tests of the vibration suppression of a small structure equipped with a magnetorheological (MR) damper. In the simulations, the proposed control strategy can offer high-performance semi-active vibration suppression, even in the presence of force delays in the damper. The experiments show that the displacement response with the proposed control is lower than that with the conventional skyhook-based control over the entire frequency range; furthermore, the desired performance can be achieved when the proposed condition function is used with velocity-proportional control. The simplicity and high performance demonstrated by the proposed control strategy make it applicable to semi-active vibration suppression of practical systems, even in the presence of unavoidable force delays in controllable dampers.

Comprehensive predictive control for vibration suppression based on piecewise constant input formulation

We propose a novel semi-active vibration suppression method based on model predictive control (MPC). Semi-active vibration suppression provides excellent damping performance, energy consumption, and stability during control. As the semi-active control input is often discontinuous, it may be difficult to predict. Hence, we combine semi-active vibration suppression and MPC to determine the control input trajectory arbitrarily. The proposed method, called predictive switching based on piecewise constant input (PSPCI), assumes that the piezoelectric charge remains constant when the control circuit is in the open state. Under this assumption, the future system state can be predicted for semi-active vibration suppression while reducing the computational load. The PSPCI method predicts the future work done by the transducer and effectively suppresses vibrations. Its effectiveness and robustness are demonstrated through simulations and experiments. The proposed PSPCI method enables the prediction of the semi-active control input and diversifies the control input determination for effective semi-active vibration suppression.

High dynamic range and high dispersion stability of a magnetorheological grease damper for semi-active vibration suppression

In this study, the dynamic range and dispersion stability of a shear-type magnetorheological (MR) grease damper were experimentally investigated as important characteristics affecting the performance of semi-active vibration suppression. Furthermore, the damper was applied to the semi-active vibration suppression of a small single-degree-of-freedom model structure subjected to seismic excitation. The performance test results of the damper indicated that it has a dynamic range of 157 times, which is much higher than that of conventional MR dampers. Also, because of the high dispersion stability of MR grease, the results showed that its performance can be kept for 9 days longer in comparison with a similar damper using MR fluid. Moreover, the structural vibration suppression test results demonstrated that the damper can suppress vibration response over a wide frequency range by applying skyhook-based control, which can take full advantage of the damper’s high dynamic range.

Semi-active Vibration Suppression by a Shear-Type MR Grease Damper with the High Dynamic Range

Semi-active Vibration Suppression by a Shear-Type MR Grease Damper with the High Dynamic Range

Recent developments in semi-active control of magnetorheological materials-based sandwich structures: A review

Magnetorheological (MR) materials are kinds of smart materials whose rheological characteristics are controllable with the application of external magnetic fields. In the last few decades, MR materials are well established as one of the leading smart materials for use in adaptive sandwich structures and systems for salient vibration control. This article reviews the semi-active vibration suppression of flexible structures with smart materials of MR fluids (MRFs) and MR elastomers (MREs). Stiffness and damping characteristics of beams, plates, panels, and shells integrating the core layer of MRFs and MREs are discussed in terms of field-dependent controllability. To keep the integrity of the knowledge, this review includes a study on free and forced vibration characteristics of sandwich structures with fully and various configurations of partial MR treatments, stability analysis of MR sandwich structures under rotating conditions and developments in identifying the optimal locations of MR sandwich structures for better vibration control are also discussed. Further, this article focuses on the role of carbon nanotubes in enhancing the field-dependent stiffness and damping properties of MR materials. A few of the most relevant research articles are reviewed and presented here briefly.

Semi-active vibration suppression using skyhook-based control by a shear-type MR grease damper

Semi-active vibration suppression using skyhook-based control by a shear-type MR grease damper

Semi-active Vibration Suppression of a Structure by a Shear-type MR Grease Damper

Semi-active Vibration Suppression of a Structure by a Shear-type MR Grease Damper

Semi-Active Vortex Induced Vibration Control of an Elastic Elliptical Cylinder with Energy Regeneration Capability

The concept of energy-regenerative damping is adopted in semi-active vortex-induced vibration (VIV) suppression of an elastically supported inclined impenetrable elliptical cylinder modeled as a two degree-of-freedom (DOF) system in laminar cross-flow at low Reynolds numbers (Re = 210). It is based on the intelligent (model free) adaptive fuzzy sliding mode control (AFSMC) strategy in conjunction with switch-based energy regenerating circuit of a tunable electromagnetic (EM) damper. The semi-active damper is linked to the plant model in a multi-field co-simulation framework via MATLAB/Simulink coupled with a user defined function in a CFD package. The AFSM controller initially calculates the desired transverse control force for suppression of the cylinder VIV. Consequently, by smart adjustment of the variable circuit load resistance, the current flow through EM damper circuit is adaptively modulated in such a way that the damping force continually tracks its active counterpart in a semi-active manner. Furthermore, when the damper is operating in the regeneration mode, the mechanical vibration energy that is traditionally dissipated as heat in conventional viscous dampers will be stored as electric charge in a capacitor. Numerical simulations demonstrate that the regenerative semi-active EM-based VIV control system can effectively suppress the cylinder motion while recovering a certain portion of mechanical vibration energy through the cooperative action of two distinct operation modes of the EM damper. Unlike conventional active control systems, the proposed system does not require a large external power supply, and at least part of the required power may be provided by the recovered energy.

Dynamic characteristics and control of magnetorheological/electrorheological sandwich structures: A state-of-the-art review

During past four decades, applications of magnetorheological and electrorheological fluids in adaptive sandwich structures have been widely studied, primarily for the purpose of vibration control. The rapid response time of controllable magnetorheological/electrorheological fluids to an applied magnetic/electric field and reversible variations in their stiffness and damping properties have been the key motivations for adaptive structures applications. This article presents a comprehensive review of the reported studies on applications of magnetorheological/electrorheological fluids for realizing active and semi-active vibration suppression in sandwich structures. The review focuses on methods of characterizing the magnetorheological/electrorheological fluids in the pre-yield region, magnetic/electric field-dependent phenomenological models describing the storage and loss moduli of fluids, experimental and analytical methods developed for vibration analysis of sandwich structures with magnetorheological/electrorheological fluid treatments, analysis of structures with partial magnetorheological/electrorheological fluid treatments and optimal treatment locations, and developments in control strategies for vibration suppression of magnetorheological/electrorheological sandwich structures. The studies on dynamic responses of fully and partially treated magnetorheological/electrorheological-based sandwich beams, plates, shells, and panels are also discussed, including the mathematical modeling methods and associated assumptions, methods of solutions, and experimental methods.

Semi-active vibration suppression for smart structures with sliding-mode control

A semi-active vibration suppression system is developed for flexible structures. The vibration suppression system comprises bimorph piezoelectric ceramic tiles shunted by a resistor–inductor electrical circuit with a switching component. The vibration suppression control is designed by tuning the optimal resistance and inductance parameters of the shunted resistor–inductor network. In this article, we propose a semi-active vibration control technique to improve the damping effect while maintaining the stability of the passive control system. The proposed control law is similar to a sliding-mode control that accelerates the convergence of the system using switching functions. This study shows that the resonant circuit functions as a type of dynamic damper for mechanical systems and that the sliding-mode control is very effective for damping the multi-mode responses. The results of the numerical simulations of a cantilevered beam show that a semi-active vibration control system is more effective in damping vibrations than a passive control system. A hardware demonstration based on a laboratory model has also been carried out. The preliminary results of the experiment show that the system is sensitive to the noise, and improved implementation of the switching circuit is needed for practical application.

Adaptive multimodal vibration suppression using fuzzy-based control with limited structural data

We propose a novel fuzzy-based method of adaptive multimodal vibration suppression with limited structural data. The adaptive control consists of fuzzy inference and a semi-active switching approach. We demonstrate it to be applicable to multimodal vibration suppression for vibrating structures, where a single piezoelectric actuator suppresses two modal vibrations simultaneously. Our fuzzy-based semi-active control requires only the structural information of natural frequencies for real-time adaptive feedback, whereas common adaptive controls require highly precise structural models or complete equations of motion. We conduct experiments in semi-active vibration suppression using the proposed fuzzy-based control, and compare the suppression performance of our fuzzy-based approach with conventional controls. The experiments indicate that the proposed fuzzy-based control demonstrates good adaptability when experiencing sudden changes in disturbance excitation, and also demonstrates high suppression performance. The fuzzy-based control can adapt to a wide range of disturbance conditions, both within and outside the range of vibration excitations assumed when the controller is designed.

Power-constrained intermittent control

In this article, input power, as opposed to the usual input amplitude, constraints are introduced in the context of intermittent control. They are shown to result in a combination of quadratic optimisation and quadratic constraints. The main motivation for considering input power constraints is its similarity with semi-active control. Such methods are commonly used to provide damping in mechanical systems and structures. It is shown that semi-active control can be re-expressed and generalised as control with power constraints and can thus be implemented as power-constrained intermittent control. The method is illustrated using simulations of resonant mechanical systems and the constrained nature of the power flow is represented using power-phase-plane plots. We believe the approach we present will be useful for the control design of both semi-active and low-power vibration suppression systems.

A COMPARATIVE STUDY OF PHENOMENOLOGICAL MODELS OF MR BRAKE BASED ON NEURAL NETWORKS APPROACH

In this paper a full-scale commercially available magnetorheological (MR) brake installed in a semi-active suspension (SAS) system is modeled and simulated. Two well-known phenomenological hysteresis models are explored: Bouc–Wen and Dahl ones. In particular, influence of their parameters on the response is evaluated and assessed. The next step is to introduce the artificial neural networks and discuss their application in the field of systems identification. Subsequently, two feedforward neural networks are created and trained to estimate parameters characterizing each of the MR damper models described. The semi-active suspension (SAS) system equipped with a MR brake is described and the detailed procedure for acquisition of the reference data used in the models validation stage is elaborated. The models outputs obtained by simulating them with the values of coefficients as identified by the networks are compared to each other as well as to the reference experimental data. Thanks to that, the comparative analysis between the suggested vibration suppression models and the full-scale MR brake is done and it is concluded which of the discussed models has a better performance. The usability of neural networks in the field of parameters estimation of the mathematical models of the real world phenomena is described as well. The novelty of the presented methodology is the application of artificial intelligence methods to estimate model parameters of a MR brake utilized in a SAS system. The results of this approach have a strong potential to be successfully implemented in the area of model-based control of semi-active vibration suppression systems.

Semi-active vibration suppression by a novel synchronized switch circuit with negative capacitance

This paper presents a new synchronized switch circuit for piezoelectric semi-active vibration control. Recently, Synchronized Switching Damping (SSD) controllers have been used to switch piezoelectric materials in order to damp vibration. In contrary to standard active and passive piezoelectric damping, these switching shunt circuits allow a small implementation and require only little power and, moreover, they offer the advantage of self-adaptation with environmental variations and their broadband frequency efficiency. However, the control performance of previous SSD approaches relies on the electrical quality factor of the switch circuit. This paper presents a novel form of the SSD with a negative capacitance, which is to maintain the environmental adaptation and bypass the influence of the quality factor to the damping system. The expression of the vibration attenuation at the resonance frequency is derived, and the effectiveness of this new circuit design is demonstrated by comparing with SSDI and negative capacitance shunt passive control of a resonant cantilever composite beam with embedded piezoelectric patch. Theoretical predictions and experimental results show a remarkable attenuation on the vibration of cantilever beam, which excels the other two techniques.

Assessment of Electrical Influence of Multiple Piezoelectric Transducers' Connection on Actual Satellite Vibration Suppression

We conduct comprehensive investigation of a semiactive vibration suppression method using piezoelectric transducers attached to structures. In our system, piezoelectric transducers are connected to an electric circuit composed of the diodes, an inductance, and a selective switch. Our method (SSDI) makes better use of counterelectromotive force to suppress the vibration, instead of simple dissipation of vibration energy. We use an actual artificial satellite to verify their high performance compared to conventional semi-active methods. As a consequence, we demonstrate that our semi-active switching method can suppress the vibration of the real artificial satellite to as much as 50% amplitude reduction. In our experiment, we reveal that the suppression performance depends on how multiple piezoelectric transducers are connected, namely, their series or parallel connection. We draw two major conclusions from theoretical analysis and experiment, for constructing effective semi-active controller using piezoelectric transducers. This paper clearly proves that the performance of the method is the connection (series or parallel) of multiple piezoelectric transducers and the their resistances dependent on frequency.

Semi-Active Vibration Control of Smart Structures with Sliding Mode Control

In this study, a semi-active vibration suppression system comprising piezoelectric elements is developed for flexible structures. The vibration suppression system comprises a cantilevered beam with bimorph piezoelectric ceramic tiles shunted by an RL electrical circuit with a switch. A general design method for vibration suppression of the beam is theoretically analyzed using mode analysis, wherein it is assumed that the piezoelectric elements are sufficiently thin and do not change the mode shape of the beam. With this assumption, the vibration suppression system for the beam is designed by tuning the optimal resistance and inductance parameters of the shunted RL network. In this paper, we propose a semi-active vibration control law to improve the damping effect while maintaining the stability of the passive control system. The proposed control law is similar to a sliding-mode control that accelerates the convergence of the system by using switching functions. As an example, numerical simulations have been performed for a cantilevered beam. This study shows that the resonant circuit functions as a type of a dynamic damper for mechanical systems and that sliding-mode control is very effective in damping the multi-mode responses. The results of the numerical simulations show that the semi-active vibration control system is practically more effective in damping vibrations than the passive control system.

The Application of Piezoelectric Materials in Smart Structures in China

Piezoelectric materials have become the most attractive functional materials for sensors and actuators in smart structures because they can directly convert mechanical energy to electrical energy and vise versa. They have excellent electromechanical coupling characteristics and excellent frequency response. In this article, the research activities and achievements on the applications of piezoelectric materials in smart structures in China, including vibration control, noise control, energy harvesting, structural health monitoring, and hysteresis control, are introduced. Special attention is given to the introduction of semi-active vibration suppression based on a synchronized switching technique and piezoelectric fibers with metal cores for health monitoring. Such mechanisms are relatively new and possess great potential for future applications in aerospace engineering.