Electromagnetic Vibration Absorber Research Articles

A nonlinear analysis of a Duffing oscillator with a nonlinear electromagnetic vibration absorber–inerter for concurrent vibration mitigation and energy harvesting

Several investigators have taken advantage of electromagnetic shunt-tuned mass dampers to achieve concurrent vibration mitigation and energy harvesting. For nonlinear structures such as the Duffing oscillator, it has been shown that the novel nonlinear electromagnetic resonant shunt-tuned mass damper inerter (NERS-TMDI) can mitigate vibration and extract energy for a wider range of frequencies and forcing amplitudes when compared to competing technologies. However, nonlinear systems such as the NERS-TMDI are known to exhibit complex stability behavior, which can strongly influence their performance in simultaneous vibration control and energy harvesting. To address this problem, this paper conducts a global stability analysis of the novel NERS-TMDI using three approaches: the multi-parametric recursive continuationWe emphasize that these assume method, Floquet theory, and Lyapunov exponents. A comprehensive parametric analysis is also performed to evaluate the impact of key design parameters on the global stability of the system. The outcome indicates the existence of complex nonlinear behavior, such as detached resonance curves, and the transition of periodic stable solutions to chaotic solutions. Additionally, a parametric study demonstrates that the nonlinear stiffness has a minimal impact on the linear stability of the system but can significantly impact the nonlinear stability performance, while the transducer coefficient has an impact on the linear and nonlinear stability NERS-TMDI. Finally, the global sensitivity analysis is performed relative to system parameters to quantify the impact of uncertainty in system parameters on the dynamics. Overall, our findings show that simultaneous vibration control and energy harvesting come with a considerable instability trade-off that limits the range of operation of the NERS-TMDI.

Analysis of the Electromagnetic Vibration Absorber (EMVA) Mechanism Placement in the MDoF System towards Vibration Reduction and Generated Electrical Energy

This research was conducted to determine the effect of the position of Electromagnetic Vibration Absorber (EMVA) to reduce the vibration of main system and to generate the energy. This article reports the results of a simulation and experimental study on the main system, which was excited by external force and the resulting vibration was reduced with an EMVA. The design of EMVA is in laboratory scale. The main system consists of a flat plate as a main mass and four springs, which are subjected to an excitation force that comes from the DC motor. The results show that both the simulation approach and experiment correspond well. The reduction of main system’s vibration is found to be affected by the position of EMVA. The maximum reduction in translation, rolling, and pitching direction occur at different position, which are at point 7 for translation and at point 1 for rolling and pitching. Meanwhile, the highest power generation occurs when the EMVA is at point 1.

New Method to Coordinate Vibration Energy Regeneration and Dynamic Performance of In-Wheel Motor Electrical Vehicles

A new method including suspension and wheel vibration energy regeneration is proposed in this study to coordinate the contradiction between vibration energy regeneration and dynamic performance of in-wheel motor electric vehicles (IWM-EVs). The influence mechanism of unsprung mass on the dynamic characteristics of IWM-EVs is investigated from the perspective of energy flow, and potential of energy regeneration of IWM-EVs is explored on this basis. A parameter sensitivity analysis of the proposed new method is conducted, and the optimal parameters are determined for a comparative simulation analysis among focus-driven electric vehicles, IWM-EVs, and IWM-EVs with linear electromagnetic dynamic vibration absorber (LEM-DVA). Results show that the proposed new method effectively improves the dynamic performance and achieves coordination between energy regeneration and dynamic performance despite its reduction of the vibration energy regeneration potential of IWM-EVs. A new structure, which integrates a linear electromagnetic damper (LEMD) and a LEM-DVA, is then proposed to implement the coordination method. The equivalent prototype and control system are designed for a hardware-in-the-loop test. The test results show good agreement with that of simulation despite some errors. This finding proves the effectiveness of the new structure in coordinating the vibration energy regeneration and dynamic performance of IWM-EVs.

Dynamic analysis of an electromagnetic vibration absorber in a non-ideal system

Dynamic analysis of an electromagnetic vibration absorber in a non-ideal system

Electromagnetic Vibration Absorber with Tunable Negative Stiffness for Variable Frequency Vibration Control

Vibration absorber usually aims to control the vibration in engineering, but few efforts focus on suppressing the low and variable frequency vibration by tuning the natural frequency. To obtain the optimal tooth layer parameters of the electromagnetic vibration absorber in this paper, the working bandwidth and corresponding linearity are reasonably optimized by establishing a nonlinear multiobjective programming function, and the results indicate that the working performances are significantly improved. The simulations illustrate that the optimized vibration absorber is within the effective stroke of the negative stiffness characteristic, and the reduction of its natural frequency can realize an apparent control effect in a wide low-frequency band for variable frequency vibration by adjusting the coil current. The experimental results demonstrate that the natural frequency of the vibration absorber is tuned to a reasonable value by adjusting the current, and a notable vibration suppression effect is achieved under the variable frequency. As the current increases from 0 to 550[Formula: see text]mA, the natural frequency of the vibration absorber can be tuned from 9[Formula: see text]Hz further to 7.2[Formula: see text]Hz for vibration control, and the vibration suppression effect can reach 62.1%.

Adaptive Electromagnetic Vibration Absorber for a Multimode Structure

All structures experience vibrations due to external dynamic force excitations, such as earthquakes and wind loadings. At resonance, the impact of this natural dynamic force on structures may lead to structural failures. Hence, an absorber is mounted to absorb vibrations from the primary system. Unfortunately, passive tuned mass absorbers can only target a single frequency. Since structural buildings possess multiple modes, an adaptive or tune-able vibration absorber is needed to attenuate the vibration in a multi-degree of freedom (MDOF) system. In this work, an adaptive electromagnetic vibration absorber (AEMVA) is proposed to eliminate the effects of vibrations and is dynamically tuned using electromagnets. By varying the current supplied to the coil, the stiffness of the AEMVA can be adjusted, resulting in a varying absorber frequency. A mathematical description of the AEMVA on a three-story prototype model building is also presented. The three-story benchmark model was used to demonstrate the effectiveness of AEMVA in absorbing multiple vibration modes, both analytically and experimentally. It is shown that 68.81 %, 50.49 %, and 33.45 % of vibration amplitude reductions were achieved at the first, second, and third modes, respectively.

Design of a tunable electromagnetic vibration absorber for transient vibration suppression under impulse

Vibration absorbers usually aim to control the steady-state vibration of harmonic excitation based on the traditional fixed point theory, but few efforts focus on suppressing the transient vibration caused by impulse excitation. In this paper, the excitation is regarded as impulse in modeling, and it can be used for impulse excitation. Thus, the transient vibration absorber is designed to control the transient vibration, and the stiffness of the absorber is a key factor to control the response of the primary system. This paper presents a tunable electromagnetic transient vibration absorber to avoid direct mechanical contact for the absorber. The analytical results of the transient response indicate that the vibration can be attenuated by adjusting the stiffness of the absorber. In order to establish the model of the electromagnetic stiffness, the absorber is divided into three equivalent virtual springs. The circular current loop is equivalent to the rectangular current loop to show the spatial distribution of the magnetic flux density in the air gap. The experimental tests demonstrate that the transient vibration of the primary system can be attenuated by 13% when the current of the coil is 6 A.

Design, analysis, control simulation, and experiment of novel electromagnetic hybrid vibration absorber

This paper presents a novel type of electromagnetic hybrid vibration absorber (EHVA) with a double-ring series permanent magnetic circuit applied to improve the two-stage vibration isolation system of marine power machinery. The EHVA comprises a mover with several groups of coils having a series connection, as well as a stator with internal permanent magnets and external permanent magnets, which form a novel magnetic circuit structure based on an improved Halbach array. In this magnet circuit, two adjacent groups of magnetic induction lines overlap at the coil position, thereby strengthening the magnetic field intensity. When the mover moves axially, the coil cuts the magnetic induction line to produce Lorentz force and magnetic damping force. First, the dynamic parameters of the EHVA were calculated based on multi-rigid-body dynamic theory and fixed-point theory. Second, the mechanical and electromagnetic structures of the EHVA were designed. Finally, a test stand was constructed, the system control channel was identified, and the simulation as well as experiment for vibration control using an [Formula: see text] controller were performed. Results indicated that the hybrid vibration reduction system under control reduced the acceleration amplitude by 12.3 dB at 30.6 Hz and achieved better vibration absorption effects between 27 and 33 Hz compared with the uncontrolled system.

Tuning of a shunted electromagnetic vibration absorber based on the maximisation of the electrical power dissipated

This paper investigates a local tuning approach for a shunted electromagnetic vibration absorber, which is based on the maximisation of the electrical power dissipated by the coil and shunt components. The study considers a simplified problem with a single-degree-of-freedom mechanical hosting system, which is excited by a white noise stochastic force. The hosting system is equipped with a coil-magnet seismic transducer, which is connected to a resistive-inductive shunt. The study examines the effectiveness of the shunted electromagnetic vibration absorber with respect to the following cost functions. Firstly, the reference cost function, which is based on the minimisation of the time-averaged kinetic energy of the hosting system. Secondly, the local cost functions, which are based on: the maximisation of the time-averaged vibration power absorbed by the shunted electromagnetic vibration absorber; the maximisation of the time-averaged mechanical power dissipated by the electromagnetic transducer and the maximisation of the time-averaged electrical power dissipated by the coil and the shunt. The study shows that, provided the transducer is lightly damped, the local cost function based on the maximisation of the electrical power dissipated by the coil and the shunt gives the same optimal tuning parameters than the reference cost function. Therefore, provided the electromagnetic transducer is properly designed, the shunt can be suitably tuned by maximising the time-averaged electrical power dissipated by the coil and shunt. This is a rather appealing practical solution since it can be implemented locally without the need of measuring the response of the hosting system and also it can be implemented in the shunt circuit without the need of extra sensors.

Design and experimental verification of self-powered electromagnetic vibration suppression and absorption system for in-wheel motor electric vehicles

A self-powered electromagnetic vibration suppression and absorption system integrated with a magnetorheological damper and a linear motor is designed to attenuate the negative effect of vertical vibration caused by the increased unsprung mass for in-wheel motor electric vehicles in this article. The magnetorheological damper is used as a suspension damper to suppress body vibration, and linear motor is used as a dynamic vibration absorber, namely, linear electromagnetic dynamic vibration absorber, to absorb tire vibration, and regenerates the vibration power to drive the magnetorheological damper, realizing self-power. Based on power flow theory, the power transfer mechanism of the vertical vibration for in-wheel motor electric vehicles and the regeneration potential are analyzed. The negative effect on the dynamic performance of in-wheel motor electric vehicles is analyzed through the root mean square of dynamic responses. Moreover, the specific structure scheme of the self-powered electromagnetic vibration suppression and absorption system is provided. The influence of system mass, stiffness, and damping of the linear electromagnetic dynamic vibration absorber on the dynamic performance is analyzed, and these parameters are optimized by particle swarm optimization. Simulation results show that in comparison with a passive damper, the self-powered electromagnetic vibration suppression and absorption system can reduce the body acceleration by 17.05%, which is better than the magnetorheological damper (10.08%). The self-powered electromagnetic vibration suppression and absorption system increases the tire dynamic load by 5.62%, but it is 8.68% less than the magnetorheological damper. Additionally, the regenerated power can offset the consumed power adequately to realize self-power. Finally, a bench test is conducted to verify the effectiveness and feasibility of the self-powered electromagnetic vibration suppression and absorption system.

Bandgap analysis of a tunable elastic-metamaterial-based vibration absorber with electromagnetic stiffness

Vibration is a mechanical phenomenon and exists throughout society. The vibrations in daily life would cause emotional discomfort as well as physical fatigue. Vibration even can give a life threat depending on its magnitude. Vibration is one of the significantly important factors to consider for the safety of the overall society, and therefore study of vibration reduction is indispensable. This paper presents a novel tunable electromagnetic vibration absorber based on an elastic metamaterial. The electromagnetic vibration absorber is a lattice structure dynamic model comprising elastic metamaterial unit cells having negative refractive index property and interconnected by springs. To verify the tunability of the elastic-metamaterial-based vibration absorber, the electromagnetic stiffness change in a finite element (FE) model of the electromagnet was analyzed through a parametric study of the air gap size, internal composition of the electromagnet, and amount of current. The conditions under which the electromagnet generates the highest electromagnetic stiffness were also explored. Each different value of electromagnetic stiffness obtained from the parametric studies was used for FE analysis of the dynamic model to investigate the influence on bandgap variations. The results reveal that the variation of electromagnetic stiffness has an effect on the location and bandwidth of bandgap. Moreover, vibration reduction was achieved due to the structural aspects of the dynamic model and the negative refractive index property of the elastic metamaterial. It is demonstrated that the elastic metamaterial vibration absorber is tunable in real time with the change of electromagnetic stiffness and has vibration reduction effect in various frequency ranges.

Electromagnetic vibration absorber for torsional vibration in high speed rotational machine

In this article, the vibration absorbing characteristics of electromagnetic (EM) vibration absorber in the rotational machine are studied. The stiffness characteristic and the damping characteristic of an EM vibration absorber are analyzed. The EM vibration absorber realizes its active controllability by tuning its stiffness coefficient and damping coefficient, and then generates the force and torque through controlling the radial tilting. The dynamic equations of rotational machine and EM vibration absorber are established, and their dynamic responses are analyzed. Theoretical analysis results show that the vibration response of rotational machine and its load rotor can be regulated by tuning the stiffness coefficient and the damping coefficient of torque generated by the EM vibration absorber. Experiments are conducted to verify the theoretical analysis result by measuring the displacement deflections of rotational machine at different rotational speeds with different damping coefficients and stiffness coefficients. Therefore, the vibration absorbing ability for torsional vibration of rotational machine is tunable by regulating the stiffness coefficient and the damping coefficient, and the control range for vibration can cover the whole working frequency of rotational machine. This method is promising to suppress the vibration of the rotational machine with high rotational speed.

Optimal Design of an Inerter-Based Dynamic Vibration Absorber Connected to Ground

Abstract This paper addresses the optimal design of a novel nontraditional inerter-based dynamic vibration absorber (NTIDVA) installed on an undamped primary system of single degree-of-freedom under harmonic and transient excitations. Our NTIDVA is based on the traditional dynamic vibration absorber (TDVA) with the damper replaced by a grounded inerter-based mechanical network. Closed-form expressions of optimal parameters of NTIDVA are derived according to an extended version of fixed point theory developed in the literature and the stability maximization criterion. The transient response of the primary system is optimized when the coupled system becomes defective, namely having three pairs of coalesced conjugate poles, the proof of which is also spelt out in this paper. Moreover, the analogous relationship between NTIDVA and electromagnetic dynamic vibration absorber is highlighted, facilitating the practical implementation of the proposed absorber. Finally, numerical studies suggest that compared with TDVA, NTIDVA can decrease the peak vibration amplitude of the primary system and enlarge the frequency bandwidth of vibration suppression when optimized by the extended fixed point technique, while the stability maximization criterion shows an improved transient response in terms of larger modal damping ratio and accelerated attenuation rate.

Design of a hybrid proportional electromagnetic dynamic vibration absorber for control of idling engine vibration

A hybrid proportional electromagnetic dynamic vibration absorber consisting of an electromagnetic actuator and an elastic element is proposed for control of engine vibration during idling. The design of the proportional electromagnetic actuator is realized considering the geometric parameters of the core to achieve nearly constant magnetic force over a broad range of its dynamic displacement but proportional to square of the current. The dynamic characteristics of the electromagnetic dynamic vibration absorber are analyzed analytically and experimentally. The effects of various geometric parameters of the actuator such as the slopes and width/height, and the air gaps on the resulting magnetic force characteristics are evaluated using a finite element model and verified experimentally. A methodology is proposed to achieve magnetic force proportional to current and consistent with the disturbance frequency. The hybrid proportional electromagnetic dynamic vibration absorber is subsequently applied to a single-degree-of-freedom primary system with an acceleration feedback control algorithm for attenuation of primary system vibration in a frequency band around the typical idling vibration frequencies. The effectiveness of the hybrid proportional electromagnetic dynamic vibration absorber is evaluated through simulations and laboratory experiments under harmonic excitations in the 20–30 Hz frequency range. Both the simulation and measurements show that the hybrid proportional electromagnetic dynamic vibration absorber can yield effective attenuation of periodic idling vibration in the frequency range considered.

Research of multi-point adaptive control strategy based on electromagnetic active vibration absorber

In order to improve the signal natural frequency of dynamic vibration absorber and eliminate the influence of nonlinear output force to the adaptive vibration absorption system. A new type of electromagnetic active vibration absorber is designed in this article. The internal magnetic circuit structure is changed through the electromagnet placed on the upper and lower, produce the electromagnetic force in two directions. Reaction force of upper mass is used to eliminate the target vibration. The effective frequency range of the vibration absorption increases, output force is basically linear. Aimed at multiple-point adaptive control strategy, a distributed multi-channel adaptive control algorithm is proposed, in which coupling between channels can be compensated on each control loop. Influence of secondary path on active control is analyzed, put forward the improved least mean square algorithm to identify the secondary. Active vibration control experiment platform is structured to verify the output force of absorber, and engineering application of the distributed multi-channel adaptive control algorithm. The results show that the distributed multi-channel adaptive control algorithm system has about 15 dB noise reduction, effect is obvious; new type of electromagnetic active vibration absorber is not limited to the natural frequency, output force can adaptive keep pace with the excitation frequency.

Application of COMSOL Multiphysics in Thermal Effect Analysis of Electromagnetic Active Vibration Absorber

At present, there are some researches in the thermal analysis of electromagnetic absorbers. The heating principle of electromagnetic absorber magnetic circuit is analysed, and the finite element method is used to numerically solve the temperature field in the working process of electromagnetic vibration absorber. The magnetic circuit simulation model of electromagnetic vibration absorber is established in Comsol Multiphysics finite element analysis software. And the grid Division, simulation analysis of the vibration absorber magnetic circuit structure of the internal temperature distribution, you can get the vibration absorber magnetic circuit in the working process of the temperature field of two-dimensional distribution graphics and magnetic circuit structure of different parts of the temperature rise contrast chart. The conclusion provides some theoretical reference for the design and research of electromagnetic active vibration absorber.

Sweeping shunted electro-magnetic tuneable vibration absorber: Design and implementation

This paper presents a study on the design and implementation of a time–varying shunted electro–magnetic Tuneable Vibration Absorber for broad–band vibration control of thin structures. A time–varying RL–shunt is used to harmonically vary the stiffness and damping properties of the Tuneable Vibration Absorber so that its mechanical fundamental natural frequency is continuously swept in a given broad frequency band whereas its mechanical damping is continuously adapted to maximize the vibration absorption from the hosting structure where it is mounted. The paper first recalls the tuning and positioning criteria for the case where a classical Tuneable Vibration Absorber is installed on a thin walled cylindrical structure to reduce the response of a resonating flexural mode. It then discusses the design of the time–varying shunt circuit to produce the desired stiffness and damping variations in the electro-magnetic Tuneable Vibration Absorber. Finally, it presents a numerical study on the flexural vibration and interior sound control effects produced when an array of these shunted electro–magnetic Tuneable Vibration Absorbers are mounted on a thin walled cylinder subject to a rain–on–the–roof stochastic excitation. The study shows that the array of proposed systems effectively controls the cylinder flexural response and interior noise over a broad frequency band without need of tuning and thus system identification of the structure. Therefore, the systems can be successfully used also on structures whose physical properties vary in time because of temperature changes or tensioning effects for example.

An electromagnetic vibration absorber with harvesting and tuning capabilities

This paper describes the development of an electromagnetic vibration absorber (EVA) with energy recovery and frequency tuning control capabilities. The essential component of the EVA is an electromagnetic transducer, interfacing between electrical and mechanical domains, connected to an external electrical circuit. So far, the use of electromagnetic devices in vibration-control applications has been driven by energy-harvesting applications. In these works, the electromagnetic transducer acts as a damper in the mechanical domain by connecting a resistance across the terminals of the device. By emulating the resistive components, some of the power that would have been dissipated in the resistor can be converted into usable power. The use of electromagnetic devices also opens the door (i) to the synthesis of more complex networks in the electrical domain, most of them impractical or too complicated to be synthesized mechanically and (ii) to the development of frequency tuning networks. We consider the possibility of using an EVA along with a resistance emulator to give a self-powered adaptive EVA. We explore the switching in of different elements across the terminals of the electromagnetic transducer in order to be able to derive new low-powered control schemes for better vibration absorption. With the underlying goal to develop high performance, energy-efficient vibration-control devices, a small scale EVA device was tested, coupled with a virtual host structure. The results presented here demonstrate the potential for self-tuning of such a device. Copyright © 2015 John Wiley & Sons, Ltd.

A self-tuning electromagnetic vibration absorber with adaptive shunt electronics

Tuned vibration absorbers (TVAs) are effective devices for vibration control in the presence of tonal excitation, but when the properties of the host structure change or the excitation frequency varies they become detuned and their performance can degrade to an unacceptable level. It is therefore desirable that the properties of the TVA can adapt to maintain optimal tuning. In this paper an electromagnetic device with an adaptive synthetic shunt impedance which provides a controllable effective mechanical stiffness and damping is proposed. The shunt impedance, comprising resistance and capacitance, is implemented digitally and can be altered in real-time to allow the system to adapt. A model-based feedforward controller is designed and implemented to adapt both the shunt resistance and capacitance to ensure the tuned frequency of the vibration absorber tracks the excitation frequency. This ensures that the system has optimal performance throughout a large range of excitation frequencies. Simulations and experimental results show that the adaptive controller can successfully adapt the system to track a variable excitation frequency and hence demonstrates better performance than the equivalent non-adaptive undamped system, as well as an optimally tuned damped system.

Development of a Semi-Active Electromagnetic Vibration Absorber and Its Experimental Study

In this work, a semiactive electromagnetic vibration absorber has been developed based on a proposed electromagnetic stiffness adjustable spring model, which presents a new solution for adjusting stiffness in the field of vibration absorber devices. Simulation study on the electromagnetic spring has been performed to determine the structural parameter of the semiactive vibration absorber. An experimental rig is also built up to investigate its practical vibration control effectiveness. Firstly, the finite element model of the test bench is used to analyze its vibration characteristics. Then, the vibration reduction effect is predicted through the simulation analysis, from which the optimal control positions are found. Finally, the experimental studies are also conducted, and the results show that this semiactive electromagnetic vibration absorber has a frequency adjustment range from 21 Hz to 25 Hz, in which considerable vibration reduction from 5 dB to 10 dB can be achieved.