Vibration Suppression Technique Research Articles

Vibration Analysis and Suppression Methods of the Wing of an Underwater Glider

Vibration analysis and suppression methods are widely studied in mechanical systems. In this study, rubber damping materials were employed to enhance the vibration suppression performance of the wing of an underwater glider. A finite element model was established to analyze the vibration characteristics of the wing. The excitation characteristics of the actuator were determined by experimental methods. The wet mode shapes and corresponding frequencies of the wing of the underwater glider were investigated. The vibration suppression performance of rubber damping materials with different thickness and hardness was discussed. The optimal parameters of the rubber pads on various positions were provided to minimize the excitations from the actuator. This paper provides valuable insights for developing vibration suppression techniques for the wings of an underwater glider.

Passive vibration suppression method based on frequency domain analysis in white light vertical scanning interferometer

Vibration in manufacturing environment can significantly affects the accuracy of surface measurements, especially for the white light vertical scanning interferometry (VSI), which requires mechanical scanning for full-field measurements. This paper proposes a passive vibration suppression technique that integrates a second common-path interferometer and uses frequency domain analysis to measure vibration and reconstruct surface topography. The method is feasible for suppressing vibrations with different frequencies and amplitudes, as verified by simulation and signal recovery analysis. An in-house developed interferometer with a common optical path is used to demonstrate the measurement performance experimentally. The mathematical formula relating the vibration amplitude, the vibration frequency, the frame rate of the camera and the scanning interval is presented. The experimental results show that the precision of plane measurement decreases with increasing vibration amplitude and frequency. Moreover, the step sample signals under a maximum vibration condition of 400 nm/5 Hz are recovered, with a standard deviation of 26.07 nm for the step height measurement. As the scanning interval increases, the system can suppress higher-amplitude vibrations.

A Self-Evolving Neural Network-Based Finite-Time Control Technique for Tracking and Vibration Suppression of a Carbon Nanotube

The control of micro- and nanoscale systems is a vital yet challenging endeavor because of their small size and high sensitivity, which make them susceptible to environmental factors such as temperature and humidity. Despite promising methods proposed for these systems in literature, the chattering in the controller, convergence time, and robustness against a wide range of disturbances still require further attention. To tackle this issue, we present an intelligent observer, which accounts for uncertainties and disturbances, along with a chatter-free controller. First, the dynamics of a carbon nanotube (CNT) are examined, and its governing equations are outlined. Then, the design of the proposed controller is described. The proposed approach incorporates a self-evolving neural network-based methodology and the super-twisting sliding mode technique to eliminate the uncertainties’ destructive effects. Also, the proposed technique ensures finite-time convergence of the system. The controller is then implemented on the CNT and its effectiveness in different conditions is investigated. The numerical simulations demonstrate the proposed method’s outstanding performance in both stabilization and tracking control, even in the presence of uncertain parameters of the system and complicated disturbances.

Actuation Performance of Macro Fibre Composite (MFC) as Actuator in Vibration Reduction of Cantilever Beams

This study proposes a vibration suppression technique that uses piezoelectric material to restrict the dynamic amplitudes of a cantilever beam. The finite element analysis (FEA) model of the cantilever is created and incorporated with Macro Fiber Composite (MFC8507-P2) in the ANSYS framework. A comparative study has been performed using three different types of materials i.e., Polylactic acid (PLA), PLA with Short Carbon Fibers (PLA-SCF Composite), and PLA with Continuous Carbon Fibers (PLA-CCF Composite), for the beam. An external disturbance causes the beam to vibrate, and the MFC8507-P2 patch provides a counter-force to the structure to reduce vibrations. The MFC8507-P2 patch is placed at an appropriate location on each beam to suppress vibration induced by the initial fundamental modes. Modal analysis has been performed to find the natural frequencies and the contribution of each mode to the overall response under dynamic loading conditions. Transient structural analysis is performed to observe the influence of the MFC8507-P2 patch on vibration amplitude with time. Furthermore, frequency response analysis has been performed to determine the impact of the MFC8507-P2 patch on the vibration amplitude of the natural modes. The vibration response has been measured at the tip of the beam and the simulation results validate that the vibration amplitude decreases as the applied voltage increases.

Design and analysis of unsymmetrical SSD based negative capacitance technique for vibration suppression

Synchronized switch damping on negative capacitance (SSDNC), as one of the nonlinear synchronized switch damping (SSD) techniques, has been received much attention in recent years. The damping effect depends on the effective voltage on the piezoelectric actuator in SSDNC control. The applicable bipolar voltage of a piezoelectric element is unsymmetrical. However, the voltage on the piezoelectric actuator is applied symmetrically in SSDNC, which greatly wastes the driving capability. An unsymmetrical SSDNC (un-SSDNC) is proposed in this paper to further boost the voltage on the PZT actuator and make full use of the driving ability to improve the control performance. A bypass capacitor, two diodes and switches are attached to the SSDNC circuit to realize unsymmetrical bipolar voltage. The control logic of the switches is introduced and the switched voltage is derived as well as the control performance. Experiments and simulations were carried out to verify the designed circuit and the theoretical results of the switched voltage. The influence of the bypass capacitor on the switched voltage and the stability of the un-SSDNC system were investigated. The voltage ratio and control performance increase with increasing bypass capacitor, but too large of bypass capacitor will cause the problem of system stability.

Spectrum-based stability analysis for fractional-order delayed resonator with order scheduling

We consider the stability analysis and controller design for a novel active vibration suppression technique, what we call the fractional-order delayed resonator (FODR), to suppress the oscillations from a single-degree-of-freedom mechanical structure. The parameterized control formulas for the associated gain and delay are firstly proposed. Then, an analytical procedure is presented to perform the complete stability analysis for the FODR alone and the coupled system. For practical implementation, the fractional feedback controller is realized by an integer-order approximate transfer function. Then, we introduce a novel control strategy named “order scheduling”, which treats the order as a tunable parameter, to enhance the control flexibility. The results show that this powerful technique can widen the feasible frequency band, improve the vibration control speed, and enhance the stability robustness of the system. Finally, three numerical cases show the viability of the proposed scheme.

Weighted evenly peak reduction method for multimodal NC-piezoelectric shunt-damping

Piezoelectric NC-shunt damping is a technique for vibration suppression by connecting an external circuit called the NC-shunt circuit (Negative capacitor shunt circuit) to a piezoelectric element attached to a mechanical structure. In this paper, we develop the multimodal NC-piezoelectric shunt-damping by proposing a new cost function, which enables to evaluate the decreases in multiple resonance peaks equally. The proposed method takes the difference between the gain peak when uncontrolled and the gain peak when the selected NC-shunt circuit is used. It then selects the smallest of the multiple vibration modes and optimizes it to be larger. Numerical examples are demonstrated to evaluate the effectiveness of the proposed cost function. In addition, we investigate the gain diagrams of the open-loop transfer functions to clarify the key issues in the broad-band vibration control performance of the NC-shunt circuit. It is shown that the vibration control is effective if the anti-resonance and resonance frequencies of the open-loop transfer function are located between the bending points of the admittance.

Designing a tuned-shunt electrodynamic metamaterial in the presence of uncertainties

Resonant structural vibrations are a common source of disruptive noise, and suppressing these vibrations is often the most direct way to reduce the noise levels. Elastic metamaterials (EMMs) consist of distributed resonant substructures, at a scale which is small compared to the wavelength of vibration. This allows these materials to be used in applications where space is limited, and more traditional vibration suppression techniques would be impractical. Tuned resonators can be designed through selection of geometry or material properties, but an alternative approach, which requires significantly less prototyping, is through the use of shunted electrodynamic inertial actuators. In this paper, a novel electrodynamic metamaterial (EDMM) is proposed consisting of an array of mass-produced inertial actuators, each connected to a tuned shunt impedance. It is considered impractical to measure the dynamic and electrical parameters of a large number of actuators, and so the effect of uncertainties in the actuators is investigated on both the performance and the stability of the EDMM.

Vibration suppression of structures using tuned mass damper technology: A state-of-the-art review

To date, considerable attention has been paid to the development of structural vibration suppression techniques. Among all vibration suppression devices and techniques, the tuned mass damper is one of the most promising technologies due to its mechanical simplicity, cost-effectiveness, and reliable operation. In this article, a critical review of the structural vibration suppression using tuned mass damper technology will be presented mainly focused on the following four categories: (1) tuned mass damper technology and its modifications, (2) tuned mass damper technology in discrete and continuous structures (mathematical modeling), (3) optimization procedure to obtain the optimally designed tuned mass damper system, and (4) active tuned mass damper and semi-active tuned mass damper with the practical realization of the tuned mass damper technologies.

Advanced Control of Switched Reluctance Motors (SRMs): A Review on Current Regulation, Torque Control and Vibration Suppression

With the increasing environmental concerns, a paradigm shift towards electric and hybrid electric vehicles is expected. Switched Reluctance Motors (SRMs) have emerged as a viable competitor to other established electrical machines. SRMs are known for their simple construction, robustness, inherent fault tolerant structure and low production and maintenance costs. Moreover, the machine has gained interest due to the absence of permanent magnets or windings in the rotor structure, which significantly reduces production costs when compared to other electric motors. The SRM, however, present some known drawbacks, such as increased torque ripple and acoustic noise production, as well as a highly nonlinear behavior. Through the use of adequate control strategies, however, the main challenges of the machine can be overcome. Thus, this paper presents a state-of-the-art review of the advanced control of SRMs, encompassing current regulation strategies, torque control strategies and vibration suppression techniques. First, two categories of current controllers are reviewed: model-independent and model-based. Next, indirect and direct torque control methods are explored. Then, three approaches to vibration suppression are discussed, namely active cancellation, current profiling and direct instantaneous force control. Lastly, a summary of each topic is presented and suggestions of future research topics are listed.

Experimental validation of vibration control in membrane structures using dielectric elastomer actuators in a vacuum environment

A vibration suppression technique for lightweight and flexible membrane structures is proposed using smart structure technology with a dielectric elastomer actuator (DEA). DEA, which is a lightweight flexible polynomial material with a large deformation and high response time, can easily be applied to membrane structures for vibration suppression over a wide frequency range. Herein, active vibration control for membrane structures with DEA is examined. A non-contact excitation system with a high-power Nd:YAG pulsed laser precisely measures the vibration responses of membrane structures. A laminated DEA is fabricated and attached to the membrane surface, generating a highly reproducible ideal impulse excitation. Then a digital control system is constructed with the laser excitation system. To demonstrate the effectiveness of the proposed method, vibration control experiments are conducted using a controller designed by H∞ control theory with the identified membrane model in both atmospheric and vacuum environments.

Metamaterial beam with graded local resonators for broadband vibration suppression

This paper investigates a technique for broadband vibration suppression using a graded metamaterial beam. A series of local resonators with the same mass but different natural frequencies are attached to the beam. The difference between the natural frequencies of neighboring local resonators is defined as the frequency spacing. The spectral element method (SEM) is used to model the graded metamaterial beam, and is verified by the corresponding finite element model (FEM). Three figures of merit are defined to quantitatively evaluate the vibration suppression performance of the proposed metamaterial beam, in terms of the attenuation bandwidth and attenuation strength. Subsequently, a design strategy is proposed, and used to tune the frequency spacing to get a wide attenuation region. A parametric study is conducted to reveal the effects of the frequency spacing and damping ratio on the vibration suppression performance of the graded metamaterial beam: with increasing frequency spacing, the attenuation region first becomes wider, then multiple discrete attenuation regions appear; and with increasing damping ratio, the transmittance response becomes flatter. A piezoelectric metamaterial beam is used to implement the proposed design strategy. Using a synthetic shunt circuit, the ‘stiffness’ of the local resonator can be tuned using a piezoelectric transducer. The FEM simulation results agree well with the developed theory for the graded metamaterial beam: with tuning of the capacitance spacing (2.4 nF), the attenuation bandwidth can be increased by about 172.8% as compared to the conventional one shunted with identical capacitances.

Design and Experimental Analysis of Composite Material with Piezoelectric Layer

The main objective of this work is to analyze the active vibration control using smart sensors and actuators in a laminated E-Glass/epoxy cyanate composite beam. The cantilevered composite beam has piezoelectric ceramic patches as smart sensors and actuators. Hand layup technique for vibration suppression is done on the fabricated E-Glass/Epoxy-cyanate composite laminated beam. Experimental modal testing is performed to achieve vibration suppression on the flexible composite beam bonded with seven circular type piezoelectric actuator elements and seven circular type sensor elements. The complete vibration suppression utilizes a data acquisition system, a real-time control system, and a functional generator, in addition to the composite beam with PZT sensor and actuator. The data acquisition hardware consists of model NI 9233 (4 channel +5 V 24 Bit IEPE Analog input I2VA 1-to earth ground).

Control of Axially Moving Systems: A Review

This paper presents a comprehensive review of significant works on active vibration control of axially moving systems. Owing to their broad applications, vibration suppression techniques for these systems have generated active research over decades. Mathematical equations for five different models (i.e., string, beam, coupled, plate, and approximated model) are outlined. Active vibration control of axially moving systems can be performed based on a finite-dimensional model described by ordinary differential equations (ODEs) or an infinite-dimensional model described by partial differential equations (PDEs). For ODE models, the sliding mode control is most representative. For PDE models, however, there exist various methods, including wave cancellation, Lyapunov method, adaptive control, and hybrid control. Control applications (lifting systems, steel industry, flexible electronics, and roll-to-roll systems) are also illustrated. Finally, several issues for future research in vibration control of axially moving systems are discussed.

Discrete-Time Implementation and Experimental Validation of a Fractional Order PD Controller for Vibration Suppression in Airplane Wings

Vibrations in airplane wings have a negative impact on the quality and safety of a flight. For this reason, active vibration suppression techniques are of extreme importance. In this paper, a smart beam is used as a simulator for the airplane wings and a fractional order PD controller is designed for active vibration mitigation. To implement the ideal fractional order controller on the smart beam unit, its digital approximation is required. In this paper, a new continuous-to-discrete-time operator is used to obtain the discrete-time approximation of the ideal fractional order PD controller. The efficiency and flexibility, as well as some guidelines for using this new operator, are given. The numerical examples show that high accuracy of approximation is obtained and that the proposed method can be considered as a suitable solution for obtaining the digital approximation of fractional order controllers. The experimental results demonstrate that the designed controller can significantly improve the vibration suppression in smart beams.

Vibration Suppression of an Underactuated Dynamic System Using Virtual Actuators

Sloshing is one of the critical problems in aerospace vehicles with liquid containers. Motion of the liquid in resonance situations can degrade the stability and performance of attitude control systems. Two important characteristics of this time varying phenomenon are sensorless and underactuated properties which lead to difficulty of attitude control system design. In this paper, a new technique based on soft sensor and virtual actuator is used to suppress the effects of fuel sloshing in an aerospace launch vehicle (ALV). For this purpose, a nonlinear dynamic model of the vehicle with mechanical model of the fuel sloshing is considered as a multibody dynamic system. The preliminary attitude control system of the vehicle is extended using the new vibration suppression technique and a numerical simulation of the nonlinear model is carried out. Results of the simulation show that the undesired effects of the fuel sloshing are effectively decreased using the proposed vibration suppression technique.

Vibration reduction and firing accuracy improvement by natural frequency optimization of a machine gun system

Structure vibration is known to influence the firing accuracy of a machine gun system. Studying the dynamic characteristics of the machine gun system and reducing its vibration response are crucial. Eigenfrequency optimization based on topology is an emerging vibration suppression technique that reduces structural vibration and stabilizes a machine gun system. This paper presents an effective and efficient method that accomplishes these tasks. The objective function is the frequency of the main vibration mode confirmed by modal and transient dynamic analyses. The frequency is maximized by subjecting topology optimization to mass constraints. Based on topology optimization results, the revised model addresses all structural and manufacturability concerns. Dynamic analysis, exterior ballistics calculation, and experimental test are conducted to verify the effectiveness of the proposed method. Results show that muzzle vibration and structure deformation are reduced and firing accuracy is remarkably improved.

Reliable and Evolvable Vibration Suppression by Self-Powered Digital Vibration Control

A reliable and evolvable vibration suppression technique using a digital processor powered by energy harvested from a piezoelectric element was developed and investigated. This technique, called a self-powered digital vibration control, benefits from both the sophisticated control logic of the digital processor and a reliable self-powered semiactive element. A system embodying this technique consists of a circuit outline, CPU, and DC/DC converter. Two experiments emulating the synchronized switch damping on inductor (SSDI) technique demonstrated its effectiveness for steady inputs as well as transient ones.

Modal Analysis of the Hydraulic Retarder Shell

The 3D model of THB40 hydraulic retarder shell was established which was based on the Pro/E modeling software. The model was simplified and was introduced to ANSYS Workbench as FEA model by ANSYS-Pro/E data interface. The constraints were imposed on the FEA model for the preceding six modal analysis. The former 6 order natural frequencies and the biggest resonance deformation is obtained to determine whether there are some vibration forms which have unfavorable effects on the vehicle and to avoid resonance phenomenon to appear. At the same time, it provides the reference for the further research of the vibration mechanism of the structure and the vibration suppression technique for practical application.

Hybrid Swarm Algorithms for Parameter Identification of an Actuator Model in an Electrical Machine

Efficient identification and control algorithms are needed, when active vibration suppression techniques are developed for industrial machines. In the paper a new actuator for reducing rotor vibrations in electrical machines is investigated. Model‐based control is needed in designing the algorithm for voltage input, and therefore proper models for the actuator must be available. In addition to the traditional prediction error method a new knowledge‐based Artificial Fish‐Swarm optimization algorithm (AFA) with crossover, CAFAC, is proposed to identify the parameters in the new model. Then, in order to obtain a fast convergence of the algorithm in the case of a 30 kW two‐pole squirrel cage induction motor, we combine the CAFAC and Particle Swarm Optimization (PSO) to identify parameters of the machine to construct a linear time‐invariant(LTI) state‐space model. Besides that, the prediction error method (PEM) is also employed to identify the induction motor to produce a black box model with correspondence to input‐output measurements.