Active Dynamic Vibration Absorber Research Articles

Basic study of structural health monitoring for layered structures subjected to vibration from a semi-active dynamic vibration absorbers

Vibration suppression of structures and structural health monitoring (SHM) are important technologies for realizing a sustainable society, and as stated in SDGs No. 11 "Sustainable cities and communities,"their importance is widely known. Semi-active dynamic vibration absorbers (SADVA) are used in vibration suppression technology, in addition to passive and active dynamic vibration absorbers. Basically, the physical properties of SADVA, which are passive elements such as the spring constant and viscous damping coefficient, can be changed externally. These dynamic vibration absorbers generally operate only when an earthquake occurs. Here, to achieve SDG No. 12 "Responsible consumption, production," we verify whether it is possible to use some of the SADVA mentioned above for SHM. The vibration data of structures is sometimes used in SHM technology. Specifically, an abnormality is diagnosed by measuring the frequency response with a sensor installed in a structure and focusing on the change in the frequency response between normal and abnormal conditions. In this study, we propose a method to identify the location and level of abnormalities in layered structures using a part of SADVA as a shaker.

A high-static-low-dynamic-stiffness delayed resonator vibration absorber

Delayed resonator (DR), which enables complete vibration suppression through loop delay tuning, has been extensively investigated as a linear active dynamic vibration absorber since its invention. Besides, the nonlinear high-static-low-dynamic stiffness (HSLDS) has been widely used in vibration isolators for broadband (yet incomplete) vibration reduction. This work combines the benefits of DR and the nonlinear HSLDS characteristics, thus creating a nonlinear DR (NDR). Three unexplored topics are considered: (1). To address the nonlinear dynamics that are made complicated by the introduction of delay and the nonlinearity coupled between the NDR and the primary structure; (2). To tune the control parameters to seek possible complete vibration suppression in the nonlinear case, and accordingly, to determine the operable frequency band; (3). To evaluate how the HSLDS characteristics can enhance the performance of the linear DR (LDR) and how to design an NDR to maximize its benefits. Without loss of generality, a classic nonlinear HSLDS structure with three springs and two links is considered, and mathematical tools and computational algorithms are introduced or proposed to efficiently address theoretical analysis. Using the parameters of an experimental setup, we show that a properly tuned NDR suppresses the vibrations on the primary structure to a sufficiently low level. Besides, the HSLDS characteristics extend the operable frequency band compared with the LDR, while strong nonlinearity limits such extension. The proposed analysis procedures for delay-coupled nonlinear dynamics, alongside the control parameter tuning, determination of operable frequency bands, and structural design rules, establish a basic theoretical framework for the NDR design.

H∞ Control-Based Optimization Design for Active and Passive Dynamic Vibration Absorber

H∞ Control-Based Optimization Design for Active and Passive Dynamic Vibration Absorber

Passivity‐based control of nonlinear active dynamic vibration absorber

AbstractIn this article, a nonlinear active dynamic vibration absorber based on passivity‐based energy shaping control is proposed. Using the proposed method, the vibrations that are excited by force and velocity disturbances simultaneously can be controlled. The control law only uses the relative displacement and velocity of the vibration system, which can be easily measured by sensors. The numerical solutions to the partial differential equations are not required in our proposed method. The main idea of the controller's parameters design is to convert a plant system with a nonlinear dynamic vibration absorber into a desired system with multiple virtual skyhook dampers. We also derive the parameters' selection guidelines for the proposed controller. The global asymptotical stability is guaranteed through passivity‐based control theory, although the parameter design is based on linearization. We verify the effectiveness of the proposed controller by some simulations on a cart‐pendulum system.

Modeling and Control Design for Flutter Suppression Using Active Dynamic Vibration Absorber

Modeling and Control Design for Flutter Suppression Using Active Dynamic Vibration Absorber

Active Vibration Absorber for Superharmonic Resonance Condition

The present paper, analyses vibration suppression of a nonlinear single degree of freedom (SDOF) spring-mass-damper system under hard harmonic excitation by attaching a piezoelectric based active dynamic vibration absorber (ADVA). The host structure consists of spring with cubic nonlinear stiffness and negligible damping. The acceleration feedback is used to provide the actuating force through ADVA on the vibrating host structure. The hard harmonic excitation on the host structure induces superharmonic resonance condition i.e. when excitation frequency nearly matches one-third of the natural frequency of the host structure. The optimal tuning ratio and damping ratio of the vibration absorber are considered to depend upon the actuating force so that one can actively tune the operating frequency of the ADVA. The method of multiple scales (MMS) is used to obtain the reduced equations to study the frequency response of the system. The analysis is carried out by studying the effect of active force and cubic nonlinear stiffness on the responses of the host structure. The results obtained by MMS are compared numerically showing good agreement.

Robust fault‐tolerant H ∞ output feedback control of active suspension and dynamic vibration absorber with finite‐frequency constraint

Currently, majorities of the robust H∞ control methods are designed for active suspensions, and seldom take the active control of the in-wheel-motor (IWM) into consideration for IWM driven electric vehicles (EVs). In this study, a robust fault-tolerant H∞ output feedback control strategy with finite-frequency constraint is proposed to synchronously control the active suspension and dynamic vibration absorber (DVA) for IWM driven EVs. Firstly, a DVA-based electric wheel model is developed, in which the IWM is designed as DVA. Furthermore, the spring-damper parameters of the DVA are matched by using particle swarm optimisation (PSO). Then, the robust fault-tolerant H∞ output feedback control strategy is developed based on linear matrix inequality, in which the finite-frequency constraint is designed in the resonance frequency range of sprung mass. Finally, simulation results validate that the PSO can effectively optimise the spring-damper parameters of the DVA. The robust fault-tolerant H∞ output feedback control with finite-frequency constraint can effectively improve the ride comfort and suppress the vertical vibration caused by IWM compared with entire frequency constraint. Meanwhile, the fault-tolerant effectiveness of the proposed method is demonstrated under the actuator faults concerning the actuator force noises and losses.

Active dynamic vibration absorber for flutter suppression

A novel flutter suppression technique is proposed using an active dynamic vibration absorber (ADVA). The ADVA is introduced by adding an active element to a classical mass-spring-damper system. This active element drives the mass by a controlling force using feedback signal from the response of the aeroelastic system. An aeroelastic mathematical model of a 2 degrees of freedom (DOFs) airfoil equipped with the proposed ADVA is established based on unsteady aerodynamics theory. The proposed ADVA is experimentally realized by a cantilever beam with a bonded Macro-fiber Composite (MFC) and a lumped mass. MFC nonlinearities are compensated by applying Prandtl-Ishlinskii approach to design a proportional integral (PI)-based hysteresis compensator controller. A test rig is designed, fabricated and the parameters of the physical airfoil model and the connected ADVA are identified. The feasibility of the ADVA for flutter suppression is assessed via a wind tunnel testing. The experimental results show that applying the closed-loop ADVA increases the airfoil flutter speed by 42.9%. Whereas the open-loop ADVA results in 26.6% improvement in the flutter speed. Moreover, if the airfoil experiences a high amplitude limit cycle oscillation (LCO), the ADVA efficiently suppresses up to 93.3% of its amplitude when turned to the closed-loop control.

Novel approach for active vibration control of a flexible missile

This paper investigates the feasibility of using an active dynamic vibration absorber (ADVA) for active vibration control of a flexible missile system through simulation. Based on the principles of a dynamic vibration absorber (DVA), a ring-type ADVA is first designed to attenuate the elastic vibration of the flexible missile, and the design of the active controller adopts the proportional-integral-derivative (PID) control algorithm. The motion equations of a flexible missile with an ADVA, which is subjected to follower thrust at its aft end, are derived using the Lagrangian approach. Taking the minimum of the root mean square (RMS) of the lateral displacement response of the center of mass as the objective function, a genetic algorithm (GA) is used to optimize the parameter of the DVA and PID controller. The numerical calculations show that the ADVA and DVA are effective in suppressing the vibration and provide approximately 41.2% and 17.6% improvement, respectively, compared with the case of no DVA. The ADVA has better performance than the DVA. When the missile is subjected to follower thrust, the effect of vibration reduction is more effective than the case without follower thrust. It is feasible to reduce vibration and improve the stability of flexible missiles by means of the ADVA.

Vibration analysis of skidding tractor with an operator during raising–lowering a tree

The aim of this article is to develop mathematical models that help at the design stage of design documentation for a skidder to determine the upcoming dynamic loads on the machine, the vibration effect on the machine and the operator, and scientifically based parameters to ensure their reduction. Vibration analysis and prediction of the skidding tractor with an operator allows predicting adverse events, prevent accidents, avoid costly and dangerous experiments, as well as optimize the design and operating modes. A particularly important degree of vibration loads affects the performance and health of the operator. The constant long-term effect of vibrations leads to increased operator fatigue and an increase in the number of errors in control. As a result, operator productivity significantly reduced. Baseline data that used in this article is related to the skidding trailer tractor TB-1M. So the results of this research may use as the foundation of future works for omitting vibration influence on the operator by designing active and smart dynamic vibration absorber for a different type of tractors. In addition, the effect of sitting stiffness and loading on the operator-tractor system have been investigated.

Suppression of Vibration Induced by Reciprocal Motion of Displacer in Cryopump with an Active Dynamic Vibration Absorber

An active dynamic vibration absorber is introduced to a cyropump system achieving ultra-high vacuum and extremely low temperature environments for fine observation and high-accuracy measurement. In a cryopump, a so-called displacer moves reciprocally for alternative adiabatic expansion and exhaust of helium gas. Such a motion induces vibration in the vacuum chamber on which the pump is fixed. It may negatively affect observation and measurement performed in the chamber. To remove this vibration effectively, an active dynamic vibration absorber is designed, fabricated and installed in the system. Both empirical and model-based approaches are applied in reducing vibration at multiple specified frequencies. Finally, the vibration is almost eliminated at five specified frequencies.

Vibration control of cryopump with an active dynamic vibration absorber

Vibration control of cryopump with an active dynamic vibration absorber

Design and control of active vibration isolation system with an active dynamic vibration absorber operating as accelerometer

This paper exhibits the development of a vibration isolation system using an active dynamic vibration absorber (ADVA) as an accelerometer in a low-frequency range; whereas, it operates as a vibration control device in a high-frequency range. The control signal of the ADVA gives an information of the low-frequency acceleration. At the same time, in the active vibration isolation system, an air spring is employed as a low-frequency control device and an inexpensive MEMS-type accelerometer is used to measure the acceleration of the vibration in a high-frequency range. The sensor fusion technique is applied to integrate the output of the MEMS-type accelerometer and the acceleration estimated from the ADVA. The motions of the vibration isolation table and the absorber mass of the ADVA are controlled by PID control. The integrated acceleration by the sensor fusion is transmitted through a low-pass filter to the air spring and through a high-pass filter into the ADVA to attain additional acceleration and velocity feedback to the PID controls. Several experimentations and observations are conducted to measure the transmissibility and compliance. The experimental and simulation results demonstrate that the performance and operative precision of the developed active vibration isolation system are improved by the additional absolute acceleration and velocity feedbacks in terms of compliance as well as transmissibility characteristics.

Transient vibration control using nonlinear convergence active vibration absorber for impulse excitation

Abstract This paper presents a nonlinear convergence algorithm for active dynamic vibration absorber (ADVA) to control the transient vibration caused by the impulse excitation. The proposed nonlinear ADVA is made up of equivalent dynamic modeling equations and frequency estimator. The ADVA is mathematically imitated by a mass body and a voice coil motor (VCM). The VCM plays two roles in this study. On one hand, the algorithm-controlled Lorentz force of the VCM is actively utilized to suppress the transient response of primary system. On the other hand, the VCM also acts as a magnetic damper, which helps attenuate the transient vibration passively. The nonlinear convergence estimator is applied to simultaneously satisfy the requirements of fast convergence rate and small steady state frequency error, which are incompatible for the linear convergence estimator. The experiments demonstrate that the nonlinear ADVA can shorten 70% of the convergence time than the linear ADVA. The nonlinear ADVA and VCM magnetic damper work together and help eliminate 95% of the uncontrolled transient vibration at 1.5 s.

Energy efficient active vibration control strategies using electromagnetic linear actuators

Energy efficient current control methods in electromagnetic linear actuators are required to minimize the electrical power requirements imposed by active vibration control strategies. In this paper an efficient bidirectional buck-boost converter is discussed in two scenarios: an active vibration isolation system and an active dynamic vibration absorber ( ADVA ) using a voice coil motor (VCM) actuator. An electrical analogous circuit of an experimental test platform is used as part of the simulation model. This test platform is based on a vibration shaker that provides the based excitation required for the single Degree of-Freedom (1DoF) vibration model under study. The proposed bidirectional non-isolated buck-boost converter can recover the energy when the VCM acts as a generator and store it for future use. Simulation results prove that this type of topology is far more efficient than linear amplifiers typically used in active vibration control. Within the context of slender structures, this efficient current control method improves the viability of using active vibration control in flexible structures such as beams.

Vibration Zeroing at Specified Frequencies in a Cryopump with an Active Dynamic Vibration Absorber

Vibration Zeroing at Specified Frequencies in a Cryopump with an Active Dynamic Vibration Absorber

Nonlinear convergence active vibration absorber for single and multiple frequency vibration control

This paper presents a nonlinear convergence algorithm for active dynamic undamped vibration absorber (ADUVA). The damping of absorber is ignored in this algorithm to strengthen the vibration suppressing effect and simplify the algorithm at the same time. The simulation and experimental results indicate that this nonlinear convergence ADUVA can help significantly suppress vibration caused by excitation of both single and multiple frequency. The proposed nonlinear algorithm is composed of equivalent dynamic modeling equations and frequency estimator. Both the single and multiple frequency ADUVA are mathematically imitated by the same mechanical structure with a mass body and a voice coil motor (VCM). The nonlinear convergence estimator is applied to simultaneously satisfy the requirements of fast convergence rate and small steady state frequency error, which are incompatible for linear convergence estimator. The convergence of the nonlinear algorithm is mathematically proofed, and its non-divergent characteristic is theoretically guaranteed. The vibration suppressing experiments demonstrate that the nonlinear ADUVA can accelerate the convergence rate of vibration suppressing and achieve more decrement of oscillation attenuation than the linear ADUVA.

Compact and Efficient Active Vibro-acoustic Control of a Smart Plate Structure

An effective wide band active control law through one kind of the Dynamic Vibration Absorber (DVA) is proposed and studied in this paper. With the help of mechanical impedance method, active DVA control law is formulated based on the passive mechanical model. The electrical DVA can generate multi-mode active damping to the structure. The host structure is an aluminum plate and acceleration signal is feedback through the controller to a collocated piezoelectric actuator. Experimental systems are setup and the open loop analysis shows that the control system has better roll-off property than the Direct Velocity Feedback (DVF) controller does. Furthermore, real time control results demonstrate that the multiple vibration modes can be suppressed simultaneously. Meanwhile, the measured sound isolation performance below 1 kHz can be up to 6 dB. The proposed method is simple and effective, which is applicable to other types of structures.

Active vibration control using mechanical and electrical analogies

Mechanical-electrical analogous circuit models are widely used in electromechanical system design as they represent the function of a coupled electrical and mechanical system using an equivalent electrical system. This research uses electrical circuits to establish a discussion of simple active vibration control principles using two scenarios: an active vibration isolation system and an active dynamic vibration absorber (DVA) using a voice coil motor (VCM) actuator. Active control laws such as gain scheduling are intuitively explained using circuit analysis techniques. Active vibration control approaches are typically constraint by electrical power requirements. The electrical analogous is a fast approach for specifying power requirements on the experimental test platform which is based on a vibration shaker that provides the based excitation required for the single Degree- of-Freedom (1DoF) vibration model under study.

能動形動吸振器を利用したアクティブ除振装置の開発

能動形動吸振器を利用したアクティブ除振装置の開発