Active Vibration Suppression Research Articles

A novel solution for dynamic behaviors of multi-span bridge plates

The present paper draws a comprehensive analysis of the free vibration characteristics and discusses modal localization phenomena of multi-span bridge plate structures through an analytical method, numerical simulations, and experimental measurements. A novel analytical solution using the generalized superposition segment method (GSSM) is first proposed to investigate the transverse vibration of a multi-span bridge, which offers complete flexibility in describing arbitrarily classical boundary conditions. Furthermore, a new experimental setup achieves precisely simply supported boundary conditions, and scaled physical models of two- and three-span bridge plates are employed to validate the analytical solution. The effect of span length mismatch is studied by analyzing the resonant frequencies and mode shapes of a multi-span bridge plate with varying span lengths. The good consistency of results by theoretical analysis, numerical simulation, and experimental measurements indicate that the proposed analytical solution can solve the vibration problem of the multi-span bridge plate efficiently and reflect the real-world boundary condition. Finally, the two modal localization behaviors are observed in theoretical analysis and experimental measurement. Through analytical solutions, numerical simulations, and experimental measurements, this study enhances the understanding of the dynamic behavior of multi-span bridges. It provides a new theoretical benchmark for predicting vibrations of multi-span bridge systems and useful insights into the transient behavior of multi-span bridge plates, suggesting several fruitful avenues for future research, including exploring passive and active control systems and vibration suppression techniques.

An isogeometric approach to dynamic structures for integrating topology optimization and optimal control at macro and micro scales

In the context of active vibration suppression, an integrated topology optimization framework is proposed for the optimal control of dynamic structures. This article formulates a new composite objective function by considering the external harmonic excitations with different excitation frequencies and the complex-valued displacement field. Within the proposed optimal control performance function, the symmetric weighting matrix, the magnitudes of which are related to the importance of the control forces, is integrated into dynamic compliance to serve the state displacement. Utilizing the non-uniform rational B-splines (NURBS) basis functions, the material interpolation model defined at control points is described by the NURBS surface, which is incorporated into the optimization formulation for optimal structural and vibration control design. The sensitivity results are deduced in terms of the pseudo-densities and the corresponding weights at control points from both macro and micro perspectives of structural dynamics. To demonstrate the effectiveness of the integrated topology optimization of dynamic structures at macro and micro scales, several numerical examples, including the topology optimization of solid beams in plane stress and Mindlin plates with 3D microstructures, are provided and discussed in terms of structural shape and topology, frequency response curve, and modal displacement.

Virtual Dynamic Vibration Absorber Trap Fusion Active Vibration Suppression Algorithm Based on Inertial Actuators for Large Flexible Space Trusses

This paper presents a virtual dynamic vibration absorber (DVA) trap fusion active vibration suppression algorithm based on inertial actuators as a solution to the harmonic vibration control problem of large flexible space trusses. Firstly, the mechanism of the inertial actuator is analyzed, and the relationship between the bandwidth of the algorithm and the intrinsic frequency of the inertial actuator is derived. Secondly, a dynamic model of the space truss is constructed. Subsequently, an analysis is conducted to determine the manner in which the virtual DVA exerts influence on the system’s dynamic characteristics. Based on this analysis, a virtual DVA trap fusion active vibration suppression algorithm is designed. Finally, the efficacy of the proposed algorithm in suppressing vibration is demonstrated through experimentation. The algorithm was demonstrated to be effective in suppressing both single-frequency harmonic vibration and multi-frequency harmonic vibration under the working conditions of single-degree-of-freedom and multi-degree-of-freedom of a flexible truss. The vibration suppression efficiency was found to be greater than 60%. It is therefore evident that the proposed algorithm has the potential to be applied to the vibration suppression of telescopes assembled in orbit in the future.

High-speed magnetically levitated centrifugal hydrogen recirculation pump in proton exchange membrane fuel cells

This paper presents a novel magnetically levitated centrifugal hydrogen recirculation pump (MLCHRP) designed for proton exchange membrane fuel cells (PEMFCs). Compared to traditional hydrogen recirculation pump, the MLCHRP offers significant advantages, including no lubrication, no mechanical friction, and active vibration suppression. However, the compact design of the pump imposes constraints on the load capacity of the active magnetic bearings (AMBs). As a result, the rotor is more susceptible to instability when subjected to unbalanced disturbance forces. This paper details the structure of the MLCHRP and provides an analysis of the basic model for unbalanced disturbance forces. A method for suppressing these unbalanced disturbances is proposed, utilizing a Linear Extended State Observer (LESO) combined with Parallel Peak Filters (PPF). The impact of this approach on system stability is thoroughly examined, and the effectiveness of the proposed method for unbalanced disturbance suppression is experimentally validated. The experimental results show that the peak-to-peak displacement of the rotor decreased by 80%. Additionally, the synchronous component in the rotor's displacement FFT was reduced by 6 dB (from -19.2 dB), and the second harmonic component decreased by 23.8 dB (from -23.7 dB). Finally, aerodynamic performance tests confirm that the MLCHRP meets the application requirements of actual PEMFCs system.

An active-passive integrated actuator based on macro fiber composite for on-orbit micro-vibration isolation

Micro-vibration suppression is crucial for satellites to ensure high imaging performance of optical loads. Herein, an active-passive integrated actuator based on macro fiber composite for micro-vibration isolation is proposed and investigated. Integrated passive and active vibration suppression is achieved by arraying a composite laminated beam consisting of the stiffness layer, damping layer and macro fiber composite layer. A dominant-frequency-correction hysteresis modeling strategy is devised to describe the asymmetric and rate-dependent voltage-force hysteresis of the proposed actuator. By treating the correction as a disturbance, the voltage-force hysteresis is compensated in combination with an extended state observer. In order to achieve resonance suppression, a full-estimation-feedback controller featuring merely displacement response feedback is developed exploiting the estimation of the extended state observer as feedback. Simulation results verify that the full-estimation-feedback controller is capable of suppressing the resonance peak with weak adverse effects on the transmissibility in the isolation band. Finally, experiments are performed to identify the voltage-force hysteresis model and evaluate the vibration isolation performance. Periodic and sweep excitation test results demonstrate that in passive mode, the actuator has a small resonance frequency of 2.3 Hz and a wide isolation band starting from 3.5 Hz. With the full-estimation-feedback controller, the resonance peak is effectively suppressed using a single signal feedback, while maintaining excellent vibration attenuation within the isolation band. The proposed actuator provides a paradigm for the design of active-passive integration vibration isolators for broadband micro-vibration suppression, which holds significant promise in enhancing the effectiveness of current observation missions.

Active disturbance rejection control for piezoelectric cantilever beam with time delay

This Letter presents an active control method for the vibration of piezoelectric structures. First, a controller based on nonlinear extended state observer is designed to improve the disturbance rejection capability of the vibration structure. Additionally, an improved nonlinear active disturbance rejection control (IMNADRC) method is combined with Smith predictor for time delay compensation, resulting in Smith predictor-based IMNADRC. Finally, numerical simulations and experiments are carried out for active vibration suppression of piezoelectric beam under fixed harmonic excitation and variable harmonic excitation, respectively. The results show that the proposed method has good control effect on structural vibration suppression and is highly adaptable to various external excitations.

Piezoelectric adaptive active vibration suppression for wind-tunnel model support sting

Due to flow separation and turbulence, the slender cantilever aircraft model support system is prone to low-frequency and large-amplitude resonance in the wind tunnel tests, resulting in a decrease in test data quality, a limited test envelope, and even threatening the safe operation of the wind tunnel. A piezoelectric active damping system based on the filtered-x least mean square algorithm is proposed to effectively suppress the vibration of the wind-tunnel model support sting. Firstly, a modified variable step least mean square algorithm is proposed to address the issue that the fixed-step algorithms limit each other in terms of convergence speed and steady-state error. Following that, a variable step filtered-x least mean square algorithm based on reference signal reconstruction is developed, and the corresponding feedback controller is designed to perform the ground tests of the piezoelectric active damping system for the wind-tunnel model support sting. The experimental results show that the proposed algorithm has a faster convergence speed and lower steady-state error than the traditional algorithms, as well as strong anti-noise and adaptive control abilities that significantly improve the active vibration suppression effect of the wind-tunnel model support sting.

Active torsional vibration suppression for integrated electric drive system considering nonlinear factors

Active torsional vibration suppression for integrated electric drive system considering nonlinear factors

Appointed time control for flexible satellite with active vibration suppression

This work addresses the problem of achieving precise appointed time attitude control and rapid active vibration suppression in flexible satellites. Firstly, an appointed time piecewise sliding mode controller is developed to ensure the convergence of attitude error to the vicinity of the origin at the appointed time. The convergence time can be predetermined using a parameter. Secondly, a modal observer is introduced to estimate the vibrations in the flexible elastic modal, and a predefined-time active vibration suppression controller is designed to mitigate the elastic vibrations in flexible solar panels. The stability of both controllers is proven using the Lyapunov theory. Finally, simulations are conducted to validate the proposed control strategy. Through comparison with two predefined time controllers, it is evident that the proposed controller achieves more precise convergence time, smoother attitude variations, and minimal magnitude of control inputs.

Individual Blade Control Approach for Active Vibration Suppression of a Lift-Offset Coaxial Rotorcraft

This study explores the best vibration reduction using an individual blade control (IBC) actuation scheme for a lift-offset coaxial helicopter in high-speed flight. The rotorcraft dynamics analysis model consists of coaxial, three-bladed counter-rotating rotors and a finite element fuselage stick model constructed based on the measured data of the XH-59A helicopter. The XH-59A helicopter is well-known for its severe vibration level encountered during the flight (over 0.5g), leading to the cancellation of the development program. A special focus is given to assessing the accuracy and efficiency of the integrated rotor–body vibration predictions evaluated between the one-way and two-way coupling methods in reference to the flight data of the vehicle. The two-way rotor–body coupled results show excellent correlations with the test data for rotor blade loads and airframe vibrations. The best actuation scenarios are then sought for the minimum vibration at the rotor hub and the pilot seat. The IBC pitch actuation effectively reduces the vibrations at both locations of the rotorcraft. Specifically, a multiple-harmonic IBC actuation enables to suppress the pilot seat vibration by 93% compared to the uncontrolled case, achieving a significantly reduced vibration level (below 0.05g).

Linear active disturbance rejection control algorithm for active vibration control of piezo-actuated beams: Theoretical and experimental studies

The active vibration control (AVC) of lightweight thin-walled structures on spacecraft has been a proven solution for vibration suppression. In this study, a linear active disturbance rejection control (LADRC) algorithm is presented for vibration suppression of piezo-actuated beams. Firstly, the governing equation of a piezo-actuated beam is obtained by using the Euler–Bernoulli beam theory and the Lagrange equation. The LADRC algorithm is designed for the piezo-actuated beam based on the governing equation. Then, the accuracy of the piezo-actuated beam model is confirmed by comparison with ANSYS and experiments. Finally, numerical simulations and experiments are carried out on the active vibration suppression of the piezo-actuated beam under the fixed harmonic excitation, variable harmonic excitation, and fixed harmonic excitation with measuring noise, respectively. The results show that the LADRC algorithm has an excellent control effect on structural vibration suppression, strong adaptability to various external excitations, and anti-noise ability.

A Modified Iterative Learning Control Approach for the Active Suppression of Rotor Vibration Induced by Coupled Unbalance and Misalignment

This paper proposes a modified iterative learning control (MILC) periodical feedback-feedforward algorithm to reduce the vibration of a rotor caused by coupled unbalance and parallel misalignment. The control of the vibration of the rotor is provided by an active magnetic actuator (AMA). The iterative gain of the MILC algorithm here presented has a self-adjustment based on the magnitude of the vibration. Notch filters are adopted to extract the synchronous (1 × Ω) and twice rotational frequency (2 × Ω) components of the rotor vibration. Both the notch frequency of the filter and the size of feedforward storage used during the experiment have a real-time adaptation to the rotational speed. The method proposed in this work can provide effective suppression of the vibration of the rotor in case of sudden changes or fluctuations of the rotor speed. Simulations and experiments using the MILC algorithm proposed here are carried out and give evidence to the feasibility and robustness of the technique proposed.

Auto-adaptive metastructure for active tunable ultra-low frequency vibration suppression

Metastructures provide a new way to solve the problem of low-frequency vibration suppression because of their unique low-frequency bandgap characteristics. Traditional metastructures usually suffer from the problem of narrow bandgap at low frequencies, which cannot tolerant to uncertainties in manufacturing process of metastructures and cannot adapt to changing working conditions. One way to overcome the shortcomings is to design metastructures with tunable bandgaps. However, it is still a challenge to realize an auto-adaptive metastructure with a highly efficient tunability. In this work, we propose an active metaplate consisting of a host plate and a periodic array of local resonators that can be collectively and actively tuned using stepping motor. We demonstrate numerically and experimentally that the proposed active metaplate can realize continuous tunable ultra-low frequency bandgap. By introducing an auto-adaptive control strategy, it can realize auto-adaptive vibration attenuation at ultra-low frequencies. The proposed active metaplate has promising application prospects since it can achieve real-time active vibration suppression by using only a few active components.

Proportional-retarded control of a quasi-zero-stiffness vibration isolator

This paper explores the control design and performance analysis of an active quasi-zero-stiffness vibration isolator utilizing the proportional-retarded (PR) control architecture. The PR architecture replaces the conventional “derivative” term in the proportional-derivative (or displacement-velocity) controller with the novel “retarded (time-delayed)” term, which is a new and effective way of active vibration suppression. Comprehensive gain-delay conjoint regulation strategies are developed for the strengthened isolation performance. For impact excitations, a complete stability analysis is conducted near the equilibrium position. Furthermore, a parameterized dominant pole placement algorithm is proposed to optimize the transient response of the PR-actuated isolator. Focusing on the rectangular pulse and long-duration step impacts, the algorithm adjusts the dominant poles to optimize the transient performance metrics, including the maximum displacement overshoot, steady-state displacement overshoot, and settling time. Regarding harmonic excitations, the delay-coupled effect is scrutinized for better low-frequency isolation performance, including the resonance frequency, nonlinear steady-state amplitude, multiple steady-state bands and nonlinearity elimination, equivalent active damping and stiffness, and absolute displacement transmissibility. In the case of random excitations, we demonstrate the superiority of the PR structure over the passive system.

A novel active and passive integrated vibration isolator based on piezoelectric stack: Characteristic analysis and experimental investigation

Passive vibration isolation has the advantages of simple structure, high reliability, and strong ability to absorb high-frequency vibration. Active vibration isolation has wide application range, strong controllability, and good vibration suppression effect for specific frequency band. Active and passive integrated vibration isolation technology combines the characteristics of both and has obvious advantages in dealing with the complex vibration environment in modern engineering practice. In this work, piezoelectric stack actuator is selected as the active control output source and vulcanized butyl rubber is used as the passive vibration absorber. The dynamic model of the novel active and passive integrated isolator is established, then the effects of different parameters on its vibration transmission performance are studied. Furthermore, a typical two-degree-of-freedom vibration isolation system model is established. By comparing the change of vibration transmissibility under different feedback forms, the design of the feedforward–feedback composite controller is applied. Finally, a double-layer vibration isolation test platform is built to verify the vibration reduction capability of the active and passive integrated isolator. The experimental results show that both the passive vibration absorption and active vibration suppression functions of this novel vibration isolator are particularly effective.

Vision based control strategy to suppress residual vibration of flexible beams for robotic assembly using wrist motion

Automated assembly tasks require industrial robots to improve the efficiency of the manufacturing process. Most rigid or flexible objects handled by robots vibrate due to motion and transient disturbance. This work proposes an active vision-based vibration suppression strategy for flexible beams by providing motion to the wrist of a robot during robotic assembly process, which reduces the time to suppress vibration. The proposed method uses a cheap monocular camera to identify objects through a virtual marker and measure their dimensions. Subsequently, finite element method based mathematical model of a flexible beam predicts the maximum error. The proposed second stage controller determines the controller input in terms of wrist motion based on the predicted maximum error. The performance of the controller is assessed through simulations and experiments on metallic beams with different material characteristics and dimensions. The controller suppresses vibration amplitude within a safe limit so that object is inserted into the slot. It was observed from experiments that the controller can reduce vibration amplitude by ~96% in less than 2 s and decrease suppression time up to ~97%. These improvements were achieved without disturbing the internal robot controller.

Active torsional vibration suppression of hybrid electric vehicle drive system based on optimal harmonic current instruction calculation method

Torsional vibrations in the drive system of a hybrid electric vehicle powered by an engine are generated by cyclic torque fluctuations. These fluctuations stem from the combustion torque and the reciprocating inertial torque of the cylinder in the reciprocating piston engine. To address this issue, a real-time engine transient torque model that considers the thermodynamic characteristics of each component is established. A method was designed to identify the torsional vibration of a powertrain based on the engine torque, electric motor torque, and powertrain model. Building on this foundation, a method was proposed to calculate the optimal harmonic current instruction of the electric motor to mitigate torsional vibration in the Hybrid electric vehicles (HEV) powertrain. Furthermore, a proportional integral-resonance (PIR) controller was designed for the injection of an electric motor reference harmonic current. Finally, a method was proposed for suppressing the torsional vibration in HEV drive systems that incorporate active harmonic current injection. The simulation and test results indicate that the proposed method can effectively diminish the amplitudes of the drive system's 2nd, 4th, 6th, and 8th harmonic torque, ensuring stable operation of the powertrain.

Singular perturbation decomposition-based ride quality control of elastic aircraft

Considering the reduction of ride comfort under wind disturbance, the ride quality control method based on singular perturbation decomposition is proposed. For the dynamic model of elastic aircraft, the singular perturbation theory is used to decouple the model into the rigid-slow subsystem and the flexible-fast subsystem. Considering the additional time-varying disturbance and aerodynamic uncertainty of the rigid subsystem, the disturbance observer is designed to estimate disturbance effect and the neural network is used to deal with model uncertainty. The adaptive robust control is constructed using the composite estimation information as feedforward compensation and the tracking error of pitch rate and normal overload as feedback design. For the flexible subsystem, a nonsingular terminal sliding mode controller is designed to achieve active vibration suppression. The ride quality control law of elastic aircraft is obtained by combining the control inputs of the rigid and flexible subsystems, and the additional normal overload and elastic mode can be quickly restrained and converged. Based on Lyapunov stability analysis, the uniformly ultimate boundedness of the system is proved. The simulation results show that the proposed method can reduce the additional normal overload at the key positions of the aircraft under discrete gust and atmospheric turbulence, and the riding quality of elastic aircraft is effectively improved.

Active vertical vibration suppression of high-speed railway vehicles by controlling internal pressure of the air spring using μ-synthesis control

In recent years, railway vehicles have become lighter since it corresponds not only to the improvement of the running speed but also to the reduction of running cost and environmental noise. On the other hand, this causes an increase in the vertical elastic vibration of the car body and the riding comfort has deteriorated. Therefore, various strategies to reduce vertical vibration have been studied. In this study, vertical vibration reduction, by controlling the internal pressure of the air spring using µ-synthesis control, is proposed. The merit of µ-synthesis control is that it can guarantee robust performance. A controller by µ-synthesis was designed for vibration reduction of a 1/6 scale railway model and compared nominal performance and robust performance with H∞ control theory. Moreover, a feasibility study of this strategy was investigated for full-scale railway vehicles through simulation.

An active piezoelectric damping vibration control system for the sting used in wind tunnel

In wind tunnel tests, the cantilever sting supporting system often suffers from low-frequency and large-amplitude resonance due to its inherent low structural damping characteristic, resulting in the degradation of data quality and structural safety. To improve wind tunnel testing safety and data accuracy, this paper is dedicated to establish an active vibration control system using piezoelectric stack actuators. A novel methodology of vibration monitoring based on modal transformation, which uses measured strain and a Strain-to-Displacement Transformation (SDT) matrix to reconstruct dynamic displacement field, is proposed herein. Meanwhile, strain sensor positions are optimized by an improved Particle Swarm Optimization (PSO) algorithm to reduce systematic estimation errors of this method. Furthermore, a Back-Propagated Neutral Network (BPNN) is established to implement a self-adaptive control strategy. A series of verification tests are performed to demonstrate the validity of the proposed system. Experimental results indicate that the relative Root Mean Square Error (RMSE) between estimated vibration displacement and measured vibration displacement is less than 3%, and a vibration attenuation of over 14 dB/Hz is achieved in ground tests, proving the superiority of this intelligent active vibration suppression system.