Active Vibration Damping Research Articles

Combined repetitive control system for active damping of forced vibrations

Combined repetitive control system for active damping of forced vibrations

Active damping of torsional vibrations in the drive train of a DFIG wind turbine

Torsional vibrations in the drive train of the doubly-fed induction generator (DFIG) based wind turbine can cause large mechanical stress and reduce the life cycle of the components. They can be easily induced by sudden changes from the turbine rotor side or grid side. In this paper, a model-based active damper of the torsional vibration designed with the linear quadratic-Gaussian (LQG) algorithm is proposed. The modelling of the drive train takes the flexibility of the rotor blades into account and utilizes a three-mass model. A combination of different simulation packages, namely FAST (Fatigue, Aerodynamics, Structure, Turbulence) and Matlab/Simulink describing important dynamics of both the mechanical and electrical side, is applied to analyse the vibrations in the drive train and test the algorithm. Simulation results show that the proposed active damping can suppress the torsional vibrations in the drive train effectively even if a gird fault occurs.

Construction and implementation of a mathematical model for damping vibrations of high-rise buildings and structures using reactive dampers

The problem of developing a computational model of an active vibration damping system of a high-rise building during an earthquake using a simple and suitable calculation scheme for high-rise buildings is considered. An approximate finite element model is presented that adequately describes the dynamic characteristics of a high-rise building. A mathematical model of a steel lattice tower is considered as an example. The ratio equations and displacement difference equations describing the behavior of reactive dampers installed in the tower are presented. An approach to optimizing the parameters of relative motion is presented. The calculation of vibration damping of a tower with reactive dampers installed on one and two levels is shown. The classification of forces with different physical properties and affecting the movement of mechanical systems is presented.

Investigation on gas-coupled vibration damping modules in free-piston Stirling generator

The free-piston Stirling generator (FPSG) is efficient and environmentally friendly. However, the inherent vibration limits FPSG’s application and shortens its life. This paper presents two novel vibration damping modules, which are placed inside the FPSG with the vibration damping piston (VDP) driven by the pressure fluctuation in the back space. One is a passive vibration damping module (PVDM), and the other is an active vibration damping module (AVDM). By adjusting the movement of VDP, the sum of the momentums of the moving parts can be zero, thus eliminating the shell’s vibration. For PVDM, the movement of VDP is adjusted by changing the opening of a needle valve. For AVDM, it is adjusted by changing the electric power of the linear alternator. The performances of these two modules are investigated based on SAGE software. Both PVDM and AVDM enable FPSG’s shell to work without vibration under the design condition with minimal reduction of thermal-acoustic-electric conversion efficiency. When the damping coefficient of vibration damping piston, external load, and heating block temperature deviate from the design value, PVDM can reduce the vibration to a certain extent. AVDM can eliminate the vibration completely under any operating conditions. For this module, the acoustic power in the back space and the input electric power are its two main energy sources, and the input electric power is relatively small. The efficiency of the whole system is reduced by no more than 1% to eliminate the vibration. Adopting these two vibration damping modules can facilitate the application of the free-piston Stirling generator.

Experimental verification of active damping of powertrain vibrations with simple fuzzy logic compensation for time-varying control period

To ensure comfortability and lifetime of components, transient vibrations in a vehicle powertrain must be suppressed. This study proposes a novel active vibration control strategy with straightforward fuzzy inference compensation for time-fluctuations of control periods of engines used as actuators. First, a model prediction algorithm including a sampled-data controller (SDC) is applied for addressing the maximal phase lag of the control input caused by the fluctuated control period. Fluctuated renewal timings of the control input that are deviated from those of the periodical operated SDC are defined by fuzzy sets. These fuzzy sets are expressed as “Nearly past timing” and “Nearly future timing.” Using a human-intuition-like fuzzy compensation with only four inference rules, unknown control inputs at fluctuated update timings are reasonably determined from such fuzzy sets and periodical control signals given by the SDC. Experiments using an actual test device are performed to investigate the damping performance of the proposed control scheme. The experimental tests demonstrate that the novel active damping strategy significantly reduces transient vibrations despite the fluctuated control period. Moreover, several different test conditions newly reveal the robustness of the fuzzy compensation against fluctuations of variable regions in the control periods.

A precision-drive hysteresis model with an equal-density weight function for GMA feedforward compensation

Giant magnetostrictive actuators (GMAs) are a widely used type of micro-nano actuator, and they are greatly significant in the field of precision engineering. The accuracy of a GMA often depends on its hysteresis model. However, existing models have some limitations, including the difficulty of identifying their parameters and the tradeoff between the quantity of modeling data required and the level of precision achieved. To solve these problems, in this paper, we propose a Preisach inverse model based on equal-density segmentation of the weight function (E-Preisach). The weight function used to calculate the displacement is first discretized. Then, to obtain a finer weight distribution, the discretized geometric units are uniformly divided by area. This can further minimize the output displacement span, and it produces a higher-precision hysteresis model. The process of parameter identification is made easier by this approach, which also resolves the difficulty of obtaining high precision using a small amount of modeling data. The Preisach and the E-Preisach inverse models were investigated and compared using experiments. At frequencies of 1 and 5 Hz, it was found that the E-Preisach inverse model decreases the maximum error of the feedforward compensation open-loop control to within 1 µm and decreases the root-mean-square error in displacement to within 0.5 µm without the need to increase the number of measured hysteresis loops. As a result, the E-Preisach inverse model streamlines the structure of the model and requires fewer parameters for modeling. This provides a high-precision modeling method using a small amount of modeling data; it will have applications in precision engineering fields such as active vibration damping and ultra-precision machining.

Axisymmetric Resonant Vibrations and Vibration Heating of an Inelastic Cylindrical Shell Compliant to Shear with Piezoelectric Actuators and Rigidly Fixed End Faces

We consider the problem of axisymmetric resonance vibrations of an inelastic cylindrical shell compliant to shear with piezoelectric actuators under the action of electromechanical monoharmonic loading. We take into account transverse shear strains, rotation inertia of a normal element, and temperature dependence of complex modules of piezopassive and piezoactive materials. The nonlinear problem is solved by using the iterative approach with respect to time within the framework of which the system of ordinary differential equations for vibrations is reduced to the integration of nonstationary heat-conduction equation by the finite-difference method. By using piezoelectric actuators, we analyze the influence of shear strains and the temperature of vibration heating on the amplitude and temperature-frequency characteristics and active damping of the resonance vibrations of the shell.

Problem of the Active Damping of Cylindrical Shell Vibrations by Discrete Forces

Problem of the Active Damping of Cylindrical Shell Vibrations by Discrete Forces

An actuator with tuneable resonant frequency for active vibration damping

This paper explores implementing active resonance frequency tuning of adaptive tuned vibration absorbers (ATVA) by coupling a vibration absorber comprising a voice coil actuator (VCA) and a sprung inertial mass to a solenoid actuator (SA). In this device, the DC current flowing through the SA generates negative magnetic stiffness and varies the equilibrium position of the nonlinear spring of the VCA, thus changing the effective stiffness of the system and its resonant frequency. The paper details the analytical design steps and the parametric sizing process of designing the SA to maximize its force density within defined magnetic, dimensions and thermal constraints. The design of the SA was verified using finite element analysis (FEA), manufactured and coupled to a VCA to make the complete ATVA system. The experimental results demonstrate the tunability of the resonance frequency of the ATVA by controlling the SA’s DC current. It is shown that the system’s resonance frequency can be shifted by up to 23% of the fundamental resonance frequency, which improves the effectiveness of the ATVA at damping a broader range of excitation frequencies.

Experimental validation of a new hybrid self-supplied crankshaft torsional vibrations damper

The increasing requirement levels for vibration mitigation in combustion engines contributes to a promotion of semi-active and active vibration dampers. Such devices are performant, but may be hindered by stability problems, and require a constant supply in energy. Recently, a rotative hybrid self-supplied damper has been introduced, designed specifically to tackle these limitations and boasting promising damping capabilities. However, the presented system was limited only to numerical investigations. The present paper constitutes an experimental validation of this damper concept. A specific test bench, able to reproduce at a smaller scale the particular non-stationary rotation of a crankshaft, is presented as well as a demonstrator for the hybrid damper. The experiments run on the bench reveal very good damping capabilities, as a complete cancellation of the torsional vibrations is reachable. Some limits revealed by the experiments, introduced by the test rig or inherent to the concept, are then discussed.

Study on the LQR Control of High-speed Elevator Car Horizontal Vibration Based on the Jumping Inertia Weight Particle Swarm Optimization

To reduce the horizontal vibration of a high-speed elevator car caused by the excitation of a guide rail more effectively, a differential magnetic suspension active guide shoe based on the principle of the differential magnetic suspension actuator is designed. Then the dynamic model of the active vibration damping system of the elevator car is established and an LQR controller is designed to reduce the horizontal vibration of the car. To search the weighting coefficient matrix of the LQR controller more efficiently, an algorithm named Jumping inertia Weight Particle Swarm Optimization (JWPSO) algorithm is proposed, and the frequently used fitness function verifies the optimization effect of the JWPSO algorithm. The weighting coefficient matrix of the LQR controller is optimized using the JWPSO algorithm. Finally, the impact of the JWPSO algorithm-optimized LQR controller is verified by MATLAB. The simulation result shows that the designed active vibration controller can effectively attenuate the horizontal vibration of the elevator car, and the control effect is significantly better than the LQR controller optimized by the GA algorithm and the H-inf controller optimized by LMI. This paper provided a new method for horizontal vibration reduction of the high-speed elevator car.

Adaptive Model-Free Gain Tuning for Active Damping of Machine Tool Vibrations

Adaptive Model-Free Gain Tuning for Active Damping of Machine Tool Vibrations

Active Vibration Control Technology in China

In the field of engineering, vibration usually leads to structural wear, fatigue, loosening and fracture, which has always been a head-scratching problem to engineers. Researchers introduced a series of solutions to attenuate vibration, such as a physical isolator, damper, or absorber, which later has been named passive vibration control (PVC) technology. The basic idea of PVC is to transfer the vibration energy of the main structure to local/additional structures and finally convert it to heat dissipation. Actually, PVC technology has been widely applied in all fields of engineering. However, with the development of industrialization, the disadvantages of PVC, like poor flexibility, large mass and volume, and limited vibration reduction effect, restrict its application in extreme environments. Under such circumstances, an alternative technology called active vibration control (AVC) has gradually attracted extensive attention. AVC introduces the sensors, actuators and control theory into the vibration control system and reduces or eliminates the unwelcome vibration by adjusting the inherent parameters such as stiffness or damping of the structures dynamically, or directly adding secondary vibration sources to suppress the vibration by superposition principle. Compared with PVC, AVC has the advantages of high flexibility, strong environmental adaptability and good low-frequency control capacity. The prototype of AVC can be traced back to the patent for active noise elimination proposed by German physicist Lueg in the 1930s. In the 1950s, Chinese scientist Hsue-shen Tsien published Engineering Cybernetics [1], a monograph that extended the automatic control theory into practical engineering, which laid the theoretical foundation for AVC. Subsequently, various AVC technologies, e.g., active vibration isolation, active vibration damping, and active vibration absorption, have been widely investigated. Nowadays, AVC has been developed into a multi-disciplinary technology including dynamics, cybernetics, system theory, information theory, and other disciplines.

Electrodynamic long-stroke drive as an inertial compensator of low-frequency vibroactive forces

The article discusses various possibilities of using an electrodynamic drive with an increased displacement of a movable permanent magnet as a low-frequency inertial compensator of vibroactive forces.The main attention is paid to the analysis of an active dynamic vibration damper (ADVD) when installing an electrodynamic compensator (EDC) on the base near vibration supports and when connecting the EDC moving mass with a vibroactive mass using a spring. It is shown that the considered ADVD is effective as a vibration isolator in the low-frequency range.

Design of Quasipolynomial-Based Controllers with Dynamical Parameters - Application to Active Vibration Damping

In order to achieve a partial pole placement for linear time-invariant systems including time-delays in their models’ representation, a method for the design of quasipolynomial-based controllers has been proposed in recent works. The ensuing controllers correspond to some output feedback control laws with constant parameters. It appears that such a controller has a limited number of degrees of freedom limiting the potential performances in closed-loop. To overcome this issue, we propose to modify the previous quasipolynomial-based controller by using dynamical parameters in their design. It turns out that the use of dynamical parameters corresponds to linear filtered terms in the control law of the original one. Such a controller is applied to the active vibration damping problem for a piezo-actuated flexible structure.

Effect of porosity on active vibration control of smart structure using porous functionally graded piezoelectric material

The present work investigates the active vibration control of host structure bonded with functionally graded piezoelectric material (FGPM) as sensor and actuator layer. The effect of porosity volume fraction (ψ) and volume fraction index (λ) on active vibration attenuation is investigated and compared with the dense FGPM sensor and actuator layer. For more real life applications of FGPMs, two piezoelectric materials (PZT-5H and PZT-4) are modelled smoothly in a particular direction. The mechanical and piezoelectric properties of FGPMs vary across the thickness and calculated using power – law expressions. In addition to dense FGPM, two different distributions of the porosities are investigated. Shear deformation theory of first order is used to simulate the vibration response of the host composite plate based on Hamilton’s principle. A well-established negative velocity feedback controller is deployed to obtain active vibration control of the composite structure. The numerical results reveal that the volume fraction index (λ) plays vital role in the active damping of structural vibration. The FGPM-◊ demonstrates 5.7% and 6.32% improved active vibration damping performance compared to FGPM-UD at ψ = 0.1 and ψ = 0.2 respectively. The present investigation can be utilized for further studies on active vibration control of host structures integrated with FGPMs.

Spatial Active Damping of Vibrations, Vibration Forces, and Pressure Fluctuations Transferred via Expansion Joints in Liquid-Filled Pipelines

Spatial Active Damping of Vibrations, Vibration Forces, and Pressure Fluctuations Transferred via Expansion Joints in Liquid-Filled Pipelines

Development and control of an active torsional vibration damper for vehicle powertrains

Due to environmental pollution concerns, emission regulations on internal combustion engines (ICEs) have been tightening and the importance of fuel efficiency has become pronounced. Thereupon, downsizing, downspeeding, turbo supercharging, and cylinder deactivation techniques have been implemented in designing modern ICEs. Despite their considerable benefits, these methods result in boosted torsional oscillations necessitating new vibration isolation technologies due to the limited performance of passive torsional vibration dampers. In addition, trade-offs are indispensable in the passive damper system designs since different engine operating points demand different values of oscillation attenuation parameters. Thus, this study was initiated to develop a novel active torsional vibration damper (ATVD) to attenuate the torsional vibrations of all engine operating points without making any trade-off and to open up a new comfort zone for the development of modern ICEs. Proposed ATVD is essentially a parametrically excited system that adjusts the stiffness rate, damping rate, and moment of inertia in accordance with a fuzzy logic control (FLC) law to maximize engine-borne torsional vibration attenuation capability. The ATVD performance is evaluated in a co-simulation environment by using a driving cycle with six engine operating points and its advantages over conventional passive dampers are demonstrated.

Development of a model predictive controller for an active torsional vibration damper to suppress torsional vibrations in vehicle powertrains

The pressure of exhaust emission regulations on automotive manufacturers to reduce environmental pollution and fuel consumption of internal combustion engines (ICEs) have stimulated the works on the downsizing, downspeeding, and turbo supercharging concepts which result in boosted engine torsional vibrations. Despite significant momentum in the implementation of those concepts in modern ICEs in recent decades, similar progress has not taken place in parallel at torsional vibration isolation systems. To this end, this article centers on the development and implementation of a model predictive controller (MPC) on a novel active torsional vibration damper (ATVD) in which inertia, stiffness rate, and damping rate parameters can be varied to minimize torsional vibration transmission to the vehicle powertrain. Dynamic response of the ATVD is examined using an MPC inside a closed-loop control architecture with predicted variables. The MPC structure, state-space plant model, and physical constraint definitions are composed to be utilized in prediction models at various engine operating points. The MPC performance is evaluated in a co-simulation environment using Simcenter Amesim, NX Motion, and Matlab Simulink software, and are compared with that of the fuzzy logic controller (FLC). The simulation results clearly indicate that the MPC applied to the ATVD system has certain advantages over the FLC and is able to provide satisfactory isolation of the powertrain from engine-borne torsional vibrations while satisfying the physical constraints.

Активный динамический гаситель колебаний при нестационарном режиме работы виброактивного агрегата

The paper considers a vibration isolation system, in which a force is applied to the moving mass of the active dynamic vibration damper by an actuator in proportion to the measured value of the base response. The amplitude-frequency and impulse characteristics are plotted depending on the parameters of the system, assuming the actuator without distortion generates the force proportional to the base response. It is shown that the considered vibration isolation system is quite effective in the low-frequency region, including in the resonance region of the passive system, both in stationary and nonstationary modes of vibroactive forces