Vibration Suppression Scheme Research Articles

Microvibration transfer and suppression of satellite under multi-source coupling disturbances based on energy flow analysis

The accuracy of satellites is extremely dependent on the control of the micro-vibration while the transmission paths among multiple vibration sources are complex. To reduce the impact of micro-vibration on the payloads of satellites effectively, the transmission characteristics of micro-vibrations under multi-source disturbances were analyzed, and a specific vibration suppression scheme was proposed. Based on the theoretical derivation and energy flow analysis method, the coupling transmission characteristics of micro-vibrations in the satellite under single- and multi-source disturbances were compared. The transmission characteristics of the vibration in the satellite under multi-source disturbance were obtained to determine the main transfer path. The contributions of different waveforms for elastic waves generated by vibration, namely bending wave, longitudinal wave and shear wave, to the target point were obtained by calculating the net transfer ratio to find out the dominant transfer waveform of the vibration. The vibration along the main transmission path was blocked by means of stiffened plates and an optimal vibration isolation scheme was determined by comparing the fluctuations in the vibrational energy of the payload under various stiffened ways. The results showed that the vibration energy under multi-source disturbances could not be obtained by the superposition of that under the single source. The longitudinal wave was the dominant transfer waveform of vibration with the energy to the payload accounting for 92.26%. The optimal vibration isolation treatment on the main transmission path can reduce the vibration by 79.25% on average, up to one order of magnitude.

Combining CFD and artificial neural network techniques to predict vortex-induced vibration mechanism for wind turbine tower hoisting

In this study, we consider a vortex-induced vibration suppression scheme for wind turbine tower hoisting process based on computational fluid dynamics. We propose a triangular cross-section spiral flow-disturbing device designed to suppress vibration, and we performed a three-dimensional numerical analysis on the steady-state and transient vibration responses of a simulated wind turbine tower. Considering the large amount of calculations and considerable time consumption of CFD simulation, we propose a hybrid meta-model to predict the results of a CFD simulation. The prediction results show that the accuracy of the prediction model met structural engineering design requirements, and the calculation time was effectively reduced. Thus, we establish a set of digital prediction methods for tower hoisting operation and maintenance.

Parallel Load-Bearing and Damping System Design and Test for Satellite Vibration Suppression

The traditional series-type satellite vibration suppression scheme significantly decreases satellite frequency, which leads to difficulty in controlling the amplitude. In the present work, a new parallel viscous damping scheme is adopted on the Payload Adaptor Fitting (PAF), which aims to integrate a load-bearing design and vibration reduction. The vibration amplitude and weight are the most important design requirements of the damping system. The Finite Element (FE) model of PAF was established. Through a series of analyses, the appropriate number and coefficient of dampers were determined. The damping force was calculated according to the damping coefficient and the relative velocity between the two ends of the damper. Based on the damping force and the installation dimensions, the damping rod was designed. The force–velocity test was carried out on the damping rod prototype, which showed its performance satisfies the requirements. With the topology optimization and sizing optimization technology, the light-weight supports were designed and manufactured. One damping rod and two supports were assembled as one set of dampers. Eight sets of dampers were installed on the PAF. Vibration tests were conducted on the damping state PAF. The results showed that the proposed system is effective at suppressing vibration and maintaining stiffness simultaneously.

Correction to: Vibration Suppression and Defect Detection Schemes in 1D Linear Spring-Mass Systems

This contains corrections to typographical errors in the paper “Vibration Suppression and Defect Detection Schemes in 1D Linear Spring-Mass Systems”.

Vibration Suppression and Defect Detection Schemes in 1D Linear Spring-Mass Systems

In this paper, we present strategies for active vibration suppression and defect detection in a one-dimensional network of an arbitrary number of coupled spring–mass units connected in series. The choice of a spring–mass system is not arbitrary, as the latter is found in many applications throughout a wide range of fields, for instance in defense detection/shielding studies, biomedical engineering, structures engineering, computer graphics and acoustics among others. The system of differential equations that model the spring–mass systems was analyzed and solved using the Laplace transform and other analytic tools. The data used in the numerical simulations were obtained by solving the associated forward problems analytically or numerically. Some of the simulations required numerical integration and minimization routines. A scheme for active vibration suppression is given via explicit formulas for the required control forces. The detect defection strategy is given in terms of an explicit formula whenever only the location or mass of a lone defect is unknown and in terms of a minimization procedure whenever more than one information about the defect(s) are unknown. Several numerical simulations were done to validate these results. As we show in the paper, the success of the vibration suppression scheme we developed depends on the speed and accuracy of the intervening active controls. Meanwhile, the defect detection algorithm only requires measurements in a sufficiently large time interval of the longitudinal vibrations in the first mass.

Study on aeolian vibration suppression schemes for large crossing span of ultra-high-voltage eight-bundle conductors

Ultra-high-voltage transmission line is prone to severely aeolian vibration, especially for the large crossing span. However, few studies were conducted previously, as a result of high nonlinearity...

Robust H∞ controller design for attitude stabilization of flexible spacecraft with input constraints

This paper addresses the attitude stabilization and vibration suppression problem for flexible spacecraft subject to model parameter uncertainty, controller perturbations, external disturbances and input constraints. The attitude model of flexible spacecraft is described and converted into a state space form in terms of passive and active vibration suppression schemes. A novel state feedback controller is proposed based on the exactly available expectation of a new variable, which is introduced to model a randomly occurring controller gain perturbation. Based on Lyapunov stability theory, sufficient conditions for the existence of the nonfragile H∞ controller considering input constraints are given based on linear matrix inequalities (LMIs) in terms of additive perturbation and multiplicative perturbation. Then, the developed controller subject to required constraints can be obtained, where the nonfragile property is fully considered to improve the tolerance to uncertainties in the controller. Numerical simulations are performed to demonstrate the effectiveness and superiority of the proposed control strategy in attitude stabilization and vibration suppression, where it should be noted that the passive vibration suppression scheme is superior for high natural frequencies while the active vibration suppression scheme is superior for low natural frequencies. Moreover, the low natural frequencies have more influence on the performance of attitude stabilization and vibration suppression.

Adaptive Control of a Flexible String System With Input Hysteresis

In this brief, a vibration suppression scheme is investigated for a flexible string system with input hysteresis. The input hysteresis is formulated as a linear desired input and a “disturbance-like” term, whose unknown bound is then estimated by an adaptive law. Without constructing a hysteresis inverse, adaptive boundary control is designed to suppress the vibrations of the flexible string, cope with the uncertainties of system parameters, and tackle the hysteresis nonlinearities. Based on the extended LaSalle’s invariance principle, asymptotic stability of the closed-loop system is also manifested. Simulations are also provided to show the effectiveness of the designed control.

Anti-disturbance rapid vibration suppression of the flexible aerial refueling hose

Abstract As an extremely dangerous phenomenon in autonomous aerial refueling (AAR), the flexible refueling hose vibration caused by the receiver aircraft’s excessive closure speed should be suppressed once it appears. This paper proposed a permanent magnet synchronous motor (PMSM) based refueling hose servo take-up system for the vibration suppression of the flexible refueling hose. A rapid back-stepping based anti-disturbance nonsingular fast terminal sliding mode (NFTSM) control scheme with a specially established finite-time convergence NFTSM observer is proposed for the PMSM based hose servo take-up system under uncertainties and disturbances. The unmeasured load torque and other disturbances in the PMSM system are reconstituted by the NFTSM observer and to be compensated during the controller design. Then, with the back-stepping technique, a rapid anti-disturbance NFTSM controller is proposed for the PMSM angular tracking to improve the tracking error convergence speed and tracking precision. The proposed vibration suppression scheme is then applied to PMSM based hose servo take-up system for the refueling hose vibration suppression in AAR. Simulation results show the proposed scheme can suppress the hose vibration rapidly and accurately even the system is exposed to strong uncertainties and probe position disturbances, it is more competitive in tracking accuracy, tracking error convergence speed and robustness.

Vibration suppression for truss core sandwich beam based on principle of nonlinear targeted energy transfer

In this work, the dynamics of a truss core sandwich beam with NES (nonlinear energy sink) device are investigated. Based on the principle of nonlinear TET (targeted energy transfer), an NES device is placed in the interior of a sandwich beam to suppress vibration of the beam. The governing equation of motion for the sandwich beam with NES device attached is derived. The vibration responses of the system are analyzed under impulse and harmonic loads. Feasibility of the vibration suppression scheme is demonstrated by investigating the relation between the mass of the NES device and suppressing effect as well as the relative motion between the sandwich beam and the NES device. In addition, the influences of the NES parameters on the suppressing effect are studied. It is worth noting that the vibration suppression is enhanced with increasing the damping of NES when the system is excited by harmonic loads and with decreasing the damping when the system is excited by impulse loads. The influence of the nonlinear characteristic of spring on the vibration suppression depends on the selection of the other parameters of the NES.

Robust adaptive horizontal vibration isolation of towed seismic streamers

The horizontal vibration of towed seismic streamers is a main reason for efficiency reduction of the seismic survey and tail tangling. A vibration suppression scheme of towed seismic streamers is investigated in this paper. The towed seismic streamer is divided into two spans, a controlled span, i.e., the low tension span, and an uncontrolled span, i.e., the high tension span, by a bird. The system model includes a hyperbolic partial differential equation with variable coefficient describing the towed seismic streamers, and an ordinary differential equation describing the dynamic of bird. Robust based-model knowledge and adaptive controllers, based on the Lyapunov method, are designed to isolate the vibration of towed seismic streamers caused by the course deviations of towing vessel, the variations of towing vessel velocity and the variations of towed seismic streamer density. The robust based-model knowledge and adaptive controllers exponentially and asymptotically drive the span-towed seismic streamer displacement to zero, respectively. A finite difference scheme is used to validate the efficiency of the control law. The proposed controller can isolate effectively the disturbance originated from the towed vessel, and can provide the improved damping but not sacrifice the isolation performance. The adaptive scheme can tolerate the lack of knowledge of some uncertain parameters and can directly execute the online adjustment of the parameters. Meanwhile, the proposed control law is robust and can resist the model uncertainty due to parameter incertitude, model error and unknown disturbance and so on. The control law only includes velocity and slope, while it does not need the displacement which is difficult to measure in the practical operations. Thus it is easy to implement.

Finite Element Charts and Active Vibration Suppression Schemes for Smart Structures Design

This article employs a finite element method to introduce Displacement-Load-Sensor voltage-Actuator voltage (DLSA) Design Charts and associated vibration suppression schemes; namely, Constant Voltage (CV), Optimum Voltage (OV), Corresponding Voltage (COV), and Truncated Corresponding Voltage (TCOV), to develop actuator control voltages with amplitude and phase information for the design of smart structures with piezoelectric sensors and actuators for active vibration suppression. These techniques can be used to (a) design the location, size, and number of actuators without resorting to complex control strategies or formal optimization techniques, (b) investigate the actuation effectiveness of surface-mounted versus embedded piezoelectric patches in similar composite structures, and (c) determine actuator control voltages analogous to a feedforward open-loop control technique. Guidelines are presented for the development of DLSA Design Charts. In addition, closed form analytical equations that can replace DLSA Design Charts, are developed and presented due to their ease of use. An Active Composite Panel (ACP) with a surface-mounted piezoelectric patch actuator for lateral vibration suppression and an Active Composite Strut (ACS) with a piezoelectric stack actuator for axial vibration suppression are considered. The ACP and ACS are employed to demonstrate the applications of the introduced DLSA Design Charts and the vibration suppression schemes for vibration suppression and actuator placement optimization. The vibration suppression of both ACP and ACS is significant over a frequency range encompassing several resonances, and is indicated by the Suppressed Vibration Energy (SVE) index. This investigation shows that the optimum location of the actuator depends on the structural mode shape, based on the criteria of maximum SVE and minimum actuator power. In general, the actuator should be placed on the panel on a sub-area, where the sum of normal strains is maximum. However, a preferred location can be determined over a range of frequencies that encompass more than one natural frequency.

Transfer Matrix Modelling of Hydraulically Actuated Flexible Robots

AbstractAccurate models of hydraulic motors and their interaction with flexible structures are needed to design motion control and vibration suppression schemes for hydraulically actuated flexible robots. The modeller of such a system faces significant challenges including capturing the dynamics of the actuator, integrating the actuator model into the system model, incorporating distributed parameter elements into the system model, determining any unknown model parameters, and creating a model that is useful for control design. This paper presents a model that overcomes all of these challenges. A transfer matrix model of a hydraulic actuator interacting with a flexible robot is developed. This model is integrated into a system model for a flexible robot. The model captures the interaction between the actuator and the structure and has been experimentally validated.

Performance of an Active Composite Strut for an Intelligent Composite Modified Stewart Platform for Thrust Vector Control

Adaptive or intelligent structures which have the capability for sensing and responding to their environment promise a novel approach to satisfying the stringent performance requirements of future space missions. This research effort focuses on the development and performance evaluation of an active composite strut (ACS) with precision positioning and active vibration suppression capabilities for use in space structures. Such ACS has potentials to be used as active strut members in Stewart platforms, modified Stewart platforms (MSPs), space truss structures, etc. The developed ACS utilizes piezoelectric actuators/sensors providing precision positioning and vibration suppression capabilities that would enhance mission performance of space structures by fine position-tuning, and potentially eliminating the nonoperational period of a satellite while minimizing the fuel consumption utilized for its position correction in a thrust vector control (TVC) application. Precision positioning of the ACS is achieved by extending or contracting its internal piezoelectric actuator. To magnify the positioning capabilities of a stack piezoelectric actuator, a miniature inchworm mechanism is designed and incorporated within the ACS. A precision positioning experimental setup is developed and employed to demonstrate the precision positioning capabilities of the developed ACS. The axial vibration suppression capability of the ACS can also be provided by its internal piezoelectric stack actuator, and is demonstrated employing a developed vibration suppression experimental setup. Analytical and finite element analysis numerical verification, simulation, and modeling of the vibration suppression capabilities of the ACS are presented. Active vibration suppression schemes, using finite element analyses, are employed to numerically demonstrate the vibration suppression capabilities of the developed ACS. The ACS housing is a composite tubing. The numerical and experimental results show that the proposed ACS offers a promising method for achieving fine tuning of positioning tolerances as well as minimizing the effects of disturbances generated during a thruster firing of a satellite for the TVC application using a MSP.

Boundary Control of an Axially Moving Steel Strip under a Spatiotemporally Varying Tension

In this paper, a vibration suppression scheme of an axially moving steel strip in the zinc galvanizing line is investigated. The moving steel strip is modeled as a moving beam, in which the tension applied to the strip is a spatiotemporally varying function. The transverse vibration of the strip is controlled by a hydraulic touch-roll actuator at the right boundary. The mathematical model of the system, which consists of a hyperbolic partial differential equation describing the dynamics of the moving beam and an ordinary differential equation describing the actuator dynamics, is derived by using the Hamilton's principle for the systems of changing mass. The Lyapunov method is employed to design a boundary control law for ensuring the vibration reduction of the system in the presence of a spatiotemporally varying tension. The exponential stability of the closed loop system under the boundary control is proved through the use of invariance principle and semigroup theory. Simulation results verify the effectiveness of the boundary control law proposed.

Robust adaptive boundary control of an axially moving string under a spatiotemporally varying tension

In this paper, a vibration suppression scheme for an axially moving string under a spatiotemporally varying tension and an unknown boundary disturbance is investigated. The lower bound of the tension variation is assumed to be sufficiently larger than the derivatives of the tension. The axially moving string system is divided into two spans, i.e., a controlled span and an uncontrolled span, by a hydraulic touch-roll actuator which is located in the middle section of the string. The transverse vibration of the controlled span part of the string is controlled by the hydraulic touch-roll actuator, and the position of the actuator is considered as the right boundary of the controlled span part. The mathematical model of the system, which consists of a hyperbolic partial differential equation describing the dynamics of the moving string and an ordinary differential equation describing the actuator dynamics, is derived by using the Hamilton's principle. The Lyapunov method is employed to design a robust boundary control law and adaptation laws for ensuring the vibration reduction of the controlled span part. The asymptotic stability of the closed loop system under the robust adaptive boundary control scheme is proved through the use of semigroup theory. Simulation results verify the effectiveness of the robust adaptive boundary controller proposed.

116 Active Composite Beam With Three Piezoelectric Patches as a New Model For the Verification of the Four Introduced Direct Vibration Suppression Schemes

116 Active Composite Beam With Three Piezoelectric Patches as a New Model For the Verification of the Four Introduced Direct Vibration Suppression Schemes

Incorporation of sliding mode control into a vibration and noise suppression scheme for a rigid rotor

This paper presents a sliding mode control algorithm to suppress the vibration of a rigid rotor supported by magnetic bearings. It is assumed that unbalance exists in the shaft and that the two planes of the shaft motion are coupled by gyroscopic forces. It is assumed that the angular rotation is small in both the normal and transverse directions and that the force and current are related linearly. The sliding mode control law is designed to be robust to rotor unbalance and transient disturbances. A boundary layer is introduced around each sliding hyperplane to eliminate the chattering phenomenon. The results from numerical simulations are presented, which not only corroborate the validity of the proposed controller, but also show the effects of various control parameters as a function of the angular speed of the rotor. Special attention is addressed to the orbital plots of the ends of the rotor. Experimental results are compared to those obtained analytically and demonstrate how the current required by the bearings is affected by the angular velocity of the rotor. [Work sponsored by ONR.]

Vibration Control of Rotationally Periodic Structures Using Passive Piezoelectric Shunt Networks and Active Compensation

This paper proposes a multi-mode vibration suppression scheme for rotationally periodic structures. Identical active-passive hybrid piezoelectric networks are applied on each of the substructures, where active charge and current feedback is used together with passive piezoelectric shunts to optimize the network performance. By exploiting the rotational periodicity, a new algorithm is synthesized to analytically determine the control parameters. It is shown that this hybrid approach can suppress all the spatial harmonics, which cannot be achieved by purely passive piezoelectric shunts. It is also observed that such a configuration requires much less control effort (voltage and power) when compared to a purely active approach.