Vibration Control Strategy Research Articles

Research on the variable mechanical properties and application in vibration control of soft magnetic entangled metallic wire material

A novel soft magnetic entangled metallic wire material (SM-EMWM) is investigated in this article, which is manufactured using the magnetoelectric-sensitive soft magnetic wires. The mechanical properties (tangent modulus, loss factor) of SM-EMWM can be tunable in the magnetic field rapidly and reversibly, and thus can be applied to vibration control systems. The quasi-static and dynamic tests in different magnetic fields were carried out, and the results show that the tangent modulus of SM-EMWM samples in a magnetic field of 500 mT can increase 2–7 times on average compared with no magnetic field condition, while the loss factor can be improved above 50%. Therefore, with the enhancement of the intensity of the magnetic field, the resonant frequency of the system with SM-EMWM increases, the peak value of response curves decreases dramatically as well. Based on the results of dynamic tests, one suitable adaptive vibration control strategy was developed and used in the tests to avoid the resonant frequency of the system, by controlling the magnetic field condition appropriately. The results show that the peak vibration transmissibility of the controlled SM-EMWM system decreases over 50%, which reveals the excellent application prospect of the SM-EMWM for the active or semi-active control vibration control in mechanical structures.

Three-dimensional vibration suppression for an Euler–Bernoulli beam with asymmetric output constraint

A vibration control strategy is addressed for the three-dimensional vibration suppression of an Euler-Bernoulli beam (EBB) subject to asymmetric output constraints in this paper. A special piecewise barrier Lyapunov function candidate is provided to prevent the asymmetric output constraint violation, and a model-based boundary control (MBC) is developed subsequently to ensure the coupled vibration reduction. Moreover, considering the parameter uncertainties, an adaptive law is designed to estimate the uncertain parameter and to update the vibration controller. The main challenge of this work is to consider the asymmetric output constraint in a nonlinear and coupled infinite-dimensional system. Finally, numerical simulations are made to present the system performance under the proposed vibration controllers which maintain the output being restrained in the predefined scope.

Vibration isolation characteristics and control strategy of parallel air spring system for transportation under abnormal road and eccentric load conditions

The precision equipment bears the vibration excited by the road roughness during transportation, and faces the risk of damage arising from the vibration. The parallel air spring vibration isolation system (PAVS) has an excellent vibration isolation performance, so has a good application prospect in the precision equipment transportation. But under the conditions of abnormal road and eccentric load, PAVS bears great vibration excitation, and the resulting large deformation of air spring makes the air spring stiffness nonlinear, so to obtain an excellent vibration isolation performance faces a great challenge. Aiming at this problem, based on the measured parameters, the nonlinear dynamics model of PAVS is proposed. Then, the influence of air spring under large deformation on the vibration isolation characteristics is discussed. Finally, under the condition of eccentricity of precision equipment, the vibration isolation characteristics of PAVS with equal height control strategy is investigated. The results show that PAVS with the equal height control strategy has good vibration isolation characteristics. So for the transportation of large precision equipment, PAVS is a potentially useful method.

Flutter Control of Long Span Suspension Bridges in Time Domain Using Optimized TMD

Suspension bridges due to their long span are susceptible against dynamic events, like air flow which can cause considerable problems for them. Flutter, as an aerodynamic phenomenon, makes bridges vibrate, whereas their amplitude gradually diverges, needed the vibration control strategies. Tuned mass damper or in brief TMD, as the simplest passive device, can be used for this purpose. The performance of it can be enhanced when it’s parameters are adjusted to their optimum values. In this paper, the TMD was optimized by meta-heuristic optimization algorithms to control the flutter of long span suspension bridges. In this regard, the Golden Gate suspension bridge and Car tracking algorithm were selected for case study and optimization process, respectively. Firstly, the flutter analysis of bridge was done by multi-mode method in the time domain, and at second part, the TMD’s parameters were simultaneously optimized for maximum increase of flutter velocity of all the vulnerable modes. The results indicated that TMD was perfectly suitable device to control the flutter of long span bridges.

Active vibration control of slewing drives with gear backlash

Geared transmissions with high reduction ratios are widely utilized in drive technology. Common to these drives is the occurrence of considerable gear backlash. If operating scenarios with repeated reversals of the rotational direction or changing load directions occur, the backlash will be traversed. To overcome the gear play, rotation angles of several hundred degrees can be required at the motor. As a result, unwanted vibrations can occur and high dynamic loads may arise. It is shown that an active vibration control strategy based on full state feedback (LQG) allows to reduce both the dynamic overload and the time for reversing the drive. The model-based design approach relies on two angular measurements only. Multibody system simulations of an exemplary drivetrain are used to verify the possible improvements.

Closed-loop online harmonic vibration estimation in DC electric motor systems

In this article, an active vibration control technique for direct-current electric motors subjected to harmonic mechanical load torque is introduced. Formulae to compute uncertain parameters of amplitude, frequency and phase angle of harmonic torque disturbances for angular velocity reference trajectory tracking are proposed. Vibrating torque disturbances are actively suppressed by the control voltage input. Mathematical modelling based on vibrating systems is adopted for purposes of online parameter estimation of oscillating signals. In this fashion, accurate estimation can be performed using measurements of the output signal only. Online parameter estimation is extended for a class of controllable dynamical engineering systems subjected to harmonic disturbances. Formulae for closed-loop online parameter estimation of harmonic vibrations on differentially flat linear dynamical systems of n degrees of freedom for efficient tracking of desired time-varying motion reference profiles are then presented. Analytical and numerical results prove that proposed formulae can be used to accurately determine the parameters of unknown harmonic vibrations, which is an excellent feature for high-efficiency active vibration control strategies.

A hybrid seismic isolation system toward more resilient structures: Shaking table experiment and fragility analysis

The effectiveness of various vibration control strategies has always been a debate among structural engineers. Seismic base isolation systems and passive dampers are recognized as two of the most economical devices which have passive mechanisms in reducing the structural vibration and responses. To this end, comprehensive biaxial shake table testings have been carried out on a building frame with and without a proposed base isolation system. The proposed device has a novel combined isolation mechanism at the structure's base. By different methods of testing, natural frequencies and viscous damping for the frame model with and without the proposed system were identified. Both structures were intensively tested under various earthquake motions, and various structural responses were recorded. The experimental results indicated that the newly proposed system is very effective in controlling the vibration of building structures and can be used to increase the seismic resilience metrics. As a complementary investigation, the incremental dynamic analysis (IDA) was conducted to develop the seismic fragility curves under both near-field and far-field strong ground motions (SGMs). The fragility estimations indicated that the proposed system has a higher collapse margin ratio (CMR) compared to conventional fixed-base frames.

Active control of high frequency chatter with machine tool feed drives in turning

This paper presents a new active vibration control strategy to mitigate high frequency regenerative chatter vibrations using machine tool feed drives. Rather than modal damping, proposed approach aims to control regenerative process dynamics to shape the Stability Lobe diagram (SLD) and attain higher material removal rates. The controller is designed as a feedback filter whose parameters are optimized to compensate regeneration. The proposed strategy is applied to actively control orthogonal (plunge) turning dynamics where >2.5 [kHz] chatter vibrations are suppressed by a fast tool servo (FTS) drive system. Stability lobes are shaped locally to reach up to 4x higher material removal rates.

A suspension system with quasi-zero stiffness characteristics and inerter nonlinear energy sink

In this article, a novel vibration control scheme of suspension systems is proposed. It combines the advantages of quasi-zero stiffness isolator, nonlinear energy sink absorber, and inerter. This proposed scheme can achieve low transmissibility, low amplitude, and low additional weight and resolve the conflict between riding comfort and handling stability. Strong nonlinear vibration equations of a quarter-vehicle suspension system are established. It also presents the detailed process of high-order harmonic approximation to obtain steady-state responses. Moreover, approximate solutions are validated by a numerical method. Furthermore, based on riding comfort and handling stability, the following four suspension systems are evaluated and compared, namely, 2-degree-of-freedom quarter-vehicle model, 2-degree-of-freedom quarter-vehicle with quasi-zero stiffness isolator, 2-degree-of-freedom quarter-vehicle with inerter-nonlinear energy sink absorber, and 2-degree-of-freedom quarter-vehicle integrated control scheme with quasi-zero stiffness and inerter-nonlinear energy sink. It is found that the integrated control scheme with quasi-zero stiffness and inerter-nonlinear energy sink can significantly improve the riding comfort and handling stability at the same time. In addition, the effects of system parameters are studied carefully. The results show that based on the reasonable design of the control system parameters, better riding comfort and handling stability can be obtained. In short, this article provides a theoretical basis for integrating quasi-zero stiffness isolators and inerter-nonlinear energy sink absorbers to improve the riding comfort and handling stability.

A coupled efficient layerwise finite element model for free vibration analysis of smart piezo-bonded laminated shells featuring delaminations and transducer debonding

This paper presents a computationally efficient multifield finite element (FE) model for accurate analysis of smart composite and sandwich shells equipped with piezoelectric patch actuators and sensors, featuring multiple delaminations and transducer debonding. It employs a facet shell element with four physical nodes and one electric node, based on the third order zigzag theory approximations for displacements and a piecewise quadratic through-thickness variation for the electric potential. A hybrid point-least squares method recently proposed by the authors is extended to impose the condition of continuity of the nonlinear displacement field at the delamination, debonding, and patch fronts. The methodology is generic for multiple patch transducers, delaminations, and debonding, occurring at any arbitrary interface and in-plane locations. The model shows excellent accuracy in comparison with the coupled full-field 3D FE solutions, for the natural frequencies and complex global, local and hybrid mode shapes of delaminated smart composite shells and soft-core sandwich plates, with partially debonded actuators and sensors. The developed model will be of immense use for the design of active vibration control and structural health monitoring strategies for smart laminated shell-type structures featuring such damages.

Distributed vibration control for large-scale flexible space structure improved by fuzzy logic system

To deal with the problem of vibration control for large-scale flexible space structure, an detailed distributed vibration control scheme with the switch control method and PD control method improved by fuzzy logic system is proposed in this paper. Firstly, the dynamic model, the actuator model and the multi-subsystem model of a large-scale flexible space structure are established. Then, a distributed control scheme is designed, which installs multiple groups of piezoelectric actuators on the support truss. The traditional methods and the improved method based on fuzzy logic system are discussed. Through ADAMS-MATLAB co-simulation platform, the effectiveness of the distributed control to suppress the vibration of large-scale flexible space structure in both Y and Z directions is verified. The simulation results show that the control precision by the improved method based on fuzzy logic system is better than traditional methods, and the control spillover is not easy to be caused.

Vibration Suppression Through Variable Stiffness and Damping Structural Joints

This paper introduces a new semi-active strategy for vibration control of truss and frame structures equipped with variable stiffness and damping joints which consist of a shape memory polymer (SMP) core reinforced by an SMP-aramid composite skin. When the joints are actuated to the transition temperature through thermal actuation, the SMP core transitions from a glassy to a rubbery state through a viscoelastic region, which causes a stiffness reduction and an increase of damping. The mechanic behavior of the joint can be thought of as transitioning from a moment to a pin connection. This way, it is possible to cause a shift of the structure natural frequencies and to increase damping, which is employed to obtain a significant reduction of the dynamic response. This paper comprises two parts: (1) characterization of a variable stiffness and damping material model through experimental testing; (2) numerical simulations of a truss bridge and a four-story frame, which are equipped with variable stiffness and damping joints. The truss bridge (case A) is subjected to a resonance and a moving load while the four-story frame (case B) is subjected to El Centro earthquake loading. For case A under resonance loading, the dynamic response can be reduced exclusively through a frequency shift and ignoring viscoelastic effects. For case A under moving load and case B under earthquake loading, vibration suppression is mostly caused by the increase of damping due to viscoelastic effects. Control time delays due to joint heating have been included in the analysis. When the joints are actuated to the transition range 55°C–65°C, which is specific to the SMP adopted in this study, the acceleration peak amplitude reduces by up to 95% and 87%, for case A and case B, respectively. For both cases, damping increases by up to 2.2% from undamped conditions (25°C). This work has shown that the adoption of variable stiffness and damping structural joints has great potential to enable a new and effective semi-active control strategy to significantly reduce the structure response under a wide range of dynamic loading conditions.

Spectral Element Approach for Flexural Waves Control in Smart Material Beam With Single and Multiple Resonant Impedance Shunt Circuit

Abstract The accurate prediction of the dynamic characteristics of a structure is key to successful vibration control strategies. A typical vibration and wave propagation control is performed through periodic and shunted piezoelectric patches, also known as a smart material. Therefore, the smart metamaterial considers periodic arrangement of shunted piezoelectric patches providing a beam with attenuation properties which depend on the resonant behavior of the shunts. The vibration attenuation occurs due to an elastic-electrical system characterized by an internal resonance of the shunt circuit. The spectral element approach provides very accurate solutions for the structural dynamic response. In this paper, a beam-piezoelectric structure is introduced to focus on the control of flexural waves in beams with piezolayers connected to single and multiresonant shunt approaches. The smart structure is modeled using the spectral element method. It is shown that the effective wavenumber presents the locally resonant behavior at the same frequencies of the vibration attenuation for both single and multishunt approached, indicating that each shunt circuit is independently associated with a attenuation frequency. The spectral element approach presented in this paper shows to be an accurate and simple approach for the design smart metamaterial beams.

Tunable vibration control in a microelectromechanical resonator array by means of parametric coupling between mechanical and electrical modes

Vibration control in flexible structures at both the micro and macro scale has been a subject of considerable research interest over the last few decades. Various active, semi-active and passive vibration control schemes have been proposed for applications ranging from attenuating unwanted vibrations in structural components to controlling the ring down time in high-Q mechanical oscillators. Here, we present a simple, yet highly effective method to passively attenuate large amplitude resonant vibrations in an array of membrane-based microelectromechanical (MEM) resonators. By capacitively coupling the MEM array to a resonant electrical circuit tuned to half the mechanical resonance frequency, the vibrational energy in the array can be converted to electrical energy via parametric mode coupling between the mechanical and electrical resonator. Simulation and experimental studies indicate that both the rate of vibration attenuation and the degree of suppression can be effectively controlled by tuning electrical parameters such as the resistance and the initial voltage in the circuit. The extension of the control scheme to multi-mode vibrations by making use of multiple shunted electrical resonators will also be briefly discussed.

Study on the Vibration Active Control of Three-Support Shafting with Smart Spring While Accelerating over the Critical Speed

Smart Spring is a kind of active vibration control device based on piezoelectric material, which can effectively suppress the vibration of the shaft system in an over-critical state, and the selection of control strategy has great influence on the vibration reduction effect of the Smart Spring. In this paper, the authors investigate the control of the over-critical vibration of the transmission shaft system with Smart Spring, based on the ADAMS and MATLAB joint simulation method. Firstly, the joint simulation model of three-support shafting with Smart Spring is established, and the over-critical speed simulation analysis of the three-support shafting under the fixed control force of the Smart Spring is carried out. The simulation results show that the maximum vibration reduction rate is 71.6%. The accuracy of the joint simulation model is verified by the experiment of the three-support shafting subcritical vibration control. On this basis, a function control force vibration control strategy with time-varying control force is proposed. By analyzing the axis orbit of the shafting, the optimal fixed control force at different speeds is obtained, the control force function is determined by polynomial fitting, and the shafting critical crossing simulation under the function control force is carried out. The simulation results show that the displacement response of the shafting under the function control force is less than that under the fixed control force in the whole speed range.

Vibration Control and Smart Integrated Transportation Strategy of Crane Systems

This paper presents number of vibration control schemes and smart integrated transportation strategies for crane systems. First, robust control problem of payload’s skew rotation in crane systems is discussed. A robust integral sliding mode controller is proposed to realize skew transportation without residual vibration. Robust stability conditions with respect to parametric uncertainties of the closed-loop system are imposed on control gains. Second, transportation of bulk material using an overhead crane system is considered, in which the transferred material can be dropped/discharged while in the air. This paper introduces a new concept, named tossing control methodology, to enhance transportation productivity. A specific type of tossing controller is established, which relies on the phenomenon of linear resonance. It will be shown that the resonance-based tossing control is able to break the time limitation of the minimum-time vibration suppression control. Simulation and experimental results are provided to verify the effectiveness of the proposed control systems. Finally, a diffusion-based obstacle-avoidance path planning method for crane systems is outlined to realize a fully autonomous crane in future.

Research on bifurcation and control of electromechanical coupling torsional vibration for wheel-side direct-driven transmission system

Aiming to the torsional vibration destabilization phenomenon of the wheel-side transmission system direct-driven by the high-power motor, the system torsional vibration bifurcation characteristics and control strategy are analyzed. Through defining the system electromechanical coupling relationship between the electrical link and the mechanical link, the dynamic model of the wheel-side direct-driven transmission system is constructed. Then, based on the Routh–Hurwitz stability criterion, the system Hopf bifurcation characteristics caused by the change of the wheel-ground friction during driving are revealed. Furthermore, with the nonlinear feedback controller and the Washout filter combined, the system torsional vibration stabilization controller is constructed by introducing the system torsional vibration signals into the motor control voltage. The results show that the linear part of the torsional vibration stabilization controller can effectively change the system stability region, as well as the cubic nonlinear part of the torsional vibration stabilization controller can control the stability of the system bifurcation points and suppress the limit cycle amplitude. The research results can provide theoretical basis and technical support for the performance improvement and integrated application of the wheel-side direct-driven transmission system in the electric bus.

Multiple-TMD-Based Structural Vibration Control for Pumped Storage Power Plants

The high-frequency resonance in the superstructure of a pumped storage power station (PSPP) due to the generation unit can shorten the service life of the power station structure and even endanger its safety. Although tuned mass dampers (TMDs) have been proved to be effective in controlling structural vibration, their application in PSPPs is rare, as high-frequency vibration control of PSPPs has not been studied. In this paper, a TMD control method is proposed based on PSPP high-frequency vibration and various TMD control strategies, and a set of high-frequency TMD equipment is designed. Results of a series of vibration reduction tests and numerical analyses show that the new TMD device can effectively control the high-order mode of the structure, and the bandwidth of the suppression frequency is extended, which shows the robustness and control efficiency of the device.

Acoustic Radiation Suppression of a Truss Core Sandwich Panel Using Decentralized Resonant Shunt Damping

The aim of the present work was to suppress the free space acoustic radiation of a truss-cored sandwich panel through the use of the decentralized resonant shunt method. First, the finite element model of the structure was established and its sound radiation characteristics were studied using the elemental radiators decomposition method. Then the decentralized modal piezoelectric shunt vibration control strategy of the Kagome sandwich panel was described in detail. In this approach, a small number of rods in the bottom truss of the sandwich panel were replaced by a piezoelectric stack transducer; each transducer was connected to a single resonant shunt which was tuned to suppress the vibration of a specific mode. The biggest advantage of the independent modal resonant shunt method is that the circuits of each mode are independent of each other; thus the large-scale parameter optimization can be decomposed into small-scale optimization problems. The results of the numerical simulation have shown that the approach that has been proposed in this paper is very effective in controlling the sound radiation of the examined structure at its resonant frequency. The results of this study can be useful in the study of the sound radiation suppression of a sandwich panel.

Vibration Analysis of Offshore Oil and Gas Platform Mechanical Equipment

Ding, N., 2020. Vibration analysis of offshore oil and gas platform mechanical equipment. In: Gong, D.; Zhang, M., and Liu, R. (eds.), Advances in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 106, pp. 633–637. Coconut Creek (Florida), ISSN 0749-0208.Based on the case of a shallow-water drilling platform, this article focuses on the vibration principle and vibration-control strategy for oil and gas platforms. Through the analysis of ANSYS and field-measured data, this research obtained several causes for violent vibrations of platforms and puts forward countermeasures to prevent platform accidents from vibration. Drilling platforms belong to offshore operation, which have great theoretical risks. In the work of substations, railways, and mines on land, the design of the operation sheet and dispatching instruction are strictly evaluated, and there should be similar attention to dispatching work of drilling platform.