Showing papers in "Journal of Vibration and Control in 2006"
TL;DR: In this paper, the authors presented a locomotion control implementation of a robotic system mimicking the undulating fins of fish, using a ribbon fin type actuation device with a series of connecting linkages attached to the robotic fish.
Abstract: This paper presents a locomotion control implementation of a robotic system mimicking the undulating fins of fish. To mimic the actual flexible fin of a real fish, we created a ribbon fin type actuation device with a series of connecting linkages and attached it to the robotic fish. By virtue of a specially designed strip withaslider, eachlinkisabletoturnandslidewithrespect to the adjacent link. The driving linkages are used to form a mechanical fin consisting of several fin segments, which are able to produce undulations, similar to those produced by actual fins. By virtue of the modular and reconfigurable fin mechanisms, two robotic fish with different fin layouts have been designed and constructed: The first prototype is a robotic stingray, swimming by undulations of a pair of lateral fins-the second is a robotic knifefish, swimming by undulations of a long anal fin. The locomotion scheme and mechatronics implementation of the robotic stingray are presented and discussed with a parametric study of the ...
141 citations
TL;DR: In this paper, a broken rotor bar fault and a combination of bearing faults (inner race, outer race, and rolling element faults) were induced into variable speed three-phase induction motors.
Abstract: In this paper we present the comparison results of induction motor fault detection using stator current, vibration, and acoustic methods. A broken rotor bar fault and a combination of bearing faults (inner race, outer race, and rolling element faults) were induced into variable speed three-phase induction motors. Both healthy and faulty signatures were acquired under different speed and load conditions. To address the detection capabilities of the above methods, comparisons are made in both the time and joint time-frequency domains. In the frequency domain, spectral differences are compared and characterized under constant speed conditions. To evaluate the detection sensitivities under non-stationary conditions (e.g. startup), a joint time-frequency method called the smoothed pseudo Wigner-Ville distribution (SPWVD) is employed to analyze non-stationary signatures. The SPWVD is a powerful technique for revealing non-stationary characteristics of motor signatures. Experimental results show that the stator ...
118 citations
TL;DR: In this paper, three semi-active control methods are investigated for use in a suspension system using a commer- cial magnetorheological damper, including the limited relative displacement method, the modified skyhook method, and the modified Rakheja-Sankar method.
Abstract: Three semi-active control methods are investigated for use in a suspension system using a commer- cial magnetorheological damper. The three control methods are the limited relative displacement method, the modified skyhook method, and the modified Rakheja-Sankar method. The method of averaging has been adopted to provide an analytical platform for analyzing the performance of the different control methods. The analytical results are verified using numerical simulation, and further are used to assess the efficiency of dif- ferent control methods. An experimental test bed has been developed to examine the three control methods under sinusoidal and random excitations. Both analytical and experimental results confirm that the Rakheja- Sankar control and modified skyhook control methods significantly reduce the root-mean-square response of both the acceleration and relative displacement of the sprung mass, while the limited relative displacement controller can only control the relative displacement of the suspension system.
116 citations
TL;DR: In this paper, a model for a nonlinear one-degree of freedom passive vibration isolator system, known as a smart engine mount, was explored and nonlinearities were employed to analyze and possibly improve the behavior of the optimal linear mount.
Abstract: This paper explores a model for a nonlinear one-degree of freedom passive vibration isolator system, known as a smart engine mount. Nonlinearities are employed to analyze and possibly improve the behavior of the optimal linear mount. Nonlinear damping and stiffness rates of the isolator have interacting effects on the dynamic behavior of the mount. The frequency response of the system is obtained using the averaging perturbation method, and a parametric analysis shows that the effect of nonlinear stiffness rate on frequency response is opposite to that of the nonlinear damping rate. Stability of the steady state periodic response has also been analyzed. Jump avoidance criteria are introduced, and the conditions for jump avoidance are studied. Closed form solutions for the absolute acceleration and relative displacement frequency responses are derived, since they are essential to use of the RMS optimization method.
70 citations
TL;DR: In this paper, a wearable lower extremity exoskeleton (LEE) was designed to augment the ability of a human to walk while carrying payloads, and a special foot unit was used to measure the zero moment points (ZMPs) of the human and the exo-body simultaneously.
Abstract: This article presents a wearable lower extremity exoskeleton (LEE) designed to augment the ability of a human to walk while carrying payloads. The ultimate goal of the current research is to design and control a wearable power-assisted system that integrates a human’s intellect as the control command. The system in this work consists of an inner exoskeleton and an outer exoskeleton. The inner system measures the movements of the human and controls the outer system, which follows the human movements and supports the payload. A special foot-unit was designed to measure the zero moment points (ZMPs) of the human and the exoskeleton simultaneously. Using the measured human ZMP as the reference, the exoskeleton’s ZMP is controlled by trunk compensation to achieve stable walking. A COTS program, xPC Target, together with toolboxes from MATLAB, were used as a real-time operating system and integrated development environment, and real-time locomotion control of the exoskeleton was successfully implemented in this...
59 citations
TL;DR: In this article, the authors present an assessment of the mechanisms of stabilization via multiplicative noise and noise-enhanced stability, and introduce the concept of noise-induced transition (NIT) in one-dimensional nonlinear systems and ship roll motion.
Abstract: Dynamical systems may experience undesirable behavior or instability, which can be eliminated using feedback control means. However, in the absence of feedback control, the stability of some systems may be increased by imposing parametric excitation. In other cases, the exit time of the system response from the stable to the unstable domain may be prolonged by imposing external noise, a phenomenon termed noise-enhanced stability (NES). This article presents an assessment of the mechanisms of stabilization via multiplicative noise and noise-enhanced stability. The first part deals with stabilization via deterministic parametric excitation of gravity-defying systems such as the inverted simple and spherical pendulums, aeroelastic structures, human walking, and quantum nonlinear couplers. The second part introduces the concept of noise-induced transition (NIT) in one-dimensional nonlinear systems and ship roll motion. Stabilization of originally unstable systems via multiplicative noise is treated in the thi...
57 citations
TL;DR: In this paper, a fractional order proportional and derivative controller for a hexapod robot, having legs with three DoF and joint actuators with saturation, when walking over ground with varyi...
Abstract: This paper studies a fractional order proportional and derivative controller for a hexapod robot, having legs with three DoF and joint actuators with saturation, when walking over ground with varyi...
57 citations
TL;DR: An impact damper is a freely moving mass, constrained by stops, located on the structural system to be controlled as mentioned in this paper, where the system is excited dynamically, the impact mass moves relative to the struct...
Abstract: An impact damper is a freely moving mass, constrained by stops, located on the structural system to be controlled. As the system is excited dynamically, the impact mass moves relative to the struct...
53 citations
TL;DR: A hybrid seismic control system for building structures, which combines a class of passive nonlinear base isolator with an active control system, and a comparison between the two strategies is presented by means of numerical simulations.
Abstract: The paper considers a hybrid seismic control system for building structures, which combines a class of passive nonlinear base isolator with an active control system. The objective of the active com...
52 citations
TL;DR: In this article, a 7.16 m long stay cable with a prototype-to-model scale factor of 8 was tested with a magnetorheological (MR) damper.
Abstract: As primary members of cable-stayed bridges, cables are susceptible to vibrations because of their low intrinsic damping. Mechanical dampers have been used to improve cable damping. Magnetorheological (MR) dampers have been proven efficient for seismic applications because of their large output damping forces, stable performance, low power requirement, and quick response from bot hl aboratory research and field practice. In this paper, experimental work was carried out to demonstrate that MR dampers are also suitable for cable vibration control. First, a MR damper was tested with various test parameters to obtain the performance curves of the MR damper under different loading conditions, including different electric currents, loading frequencies, loading wave types, and working temperatures. The MR damper was then installed on a cable to reduce the cable vibration. A 7.16 m long stay cable with a prototype-to-model scale factor of 8 was established for this study. The frequencies of the stay cable under different tension forces were measured and compared with those obtained through theoretical calculations. Then, a free vibration control test was carried out with the MR damper being installed at the 1/4 point of the cable. In the forced vibration test, a shaker was installed at 0.18 m from the lower end of the cable. The measured data show that the damper is efficient for cable vibration control within its working current range (zero to maximum) although there is a saturation effect. It was also observed that the damper could reduce cable vibration under a variety of excitation frequencies, especially for resonant vibrations.
52 citations
TL;DR: In this article, a new method of structural damage detection called Local Damage Factor (LDF) is presented, which is capable of determining the presence, severity, and location of structural damages at the same time.
Abstract: Damage in a structure alters its dynamic characteristics. Significant research has been conducted in damage detection and structural health monitoring using dynamics-based techniques. But simultaneously determining the presence, severity, and location of damage using the existing damage detection methods can still prove challenging. In this study, a new practical method of structural damage detection called Local Damage Factor (LDF) is presented, which is capable of determining the presence, severity, and location of structural damage at the same time. By including the dynamic characteristics of the intact local structure in the LDF method, the influence of structural nonlinearity, imperfections, and system noise is considered, so that the accuracy of damage detection is improved. Furthermore, a modified LDF (MLDF) method is proposed, which can detect damage without requiring benchmark data for the intact local structure. As a demonstration, the proposed LDF and MLDF methods are applied to damage detectio...
TL;DR: In this article, an extended state observer (ESO) was proposed to estimate unknown states and the load torque disturbance in a two-mass main drive system of a rolling mill.
Abstract: In the main drive system of a rolling mill, shaft torsional vibration is often generated when a motor and a roll are connected with a flexible shaft. State feedback control can effectively suppress the torsional vibration of the main drive system of a rolling mill. Because of the difficulty of measuring the load speed and the shaft torque, and moreover the sensitivity of the Luenberger observer to the model uncertainties and the noise include in the detected signal, in this paper, we propose an extended state observer (ESO), a new observer, to estimate the unknown states and the load torque disturbance. We propose an ESO and linear quadratic (LQ) based speed controller with an integrator and load torque feedforward compensation for torsional vibration suppression in a two-mass main drive system of a rolling mill. The simulation results show the controller effectively improves the performances of command following, torsional vibration suppression, and robustness to parameter variation. This is the first ti...
TL;DR: In this paper, a comparison study of blind source separation (BSS) and blind equalization (BE) algorithms has been conducted to evaluate their performance in the separation of mechanical vibrations in industrial machines.
Abstract: Many advanced techniques have been developed for diagnosis of machine faults caused by vibra- tion. They are effective if the inspected vibration is well isolated from interference caused by vibrations from adjacent components. However, the components of manufacturing machines are numerous, small, and packed closely together. Thus the signal collected by a sensor is the aggregate of vibrations from all nearby components. This, coupled with noise, makes it nearly impossible to detect the anomalous vibration gener- ated by a particular component, especially those generated by small defective components. Recently, new signal processing methods, such as blind source separation (BSS) and blind equalization (BE), have been proposed to separate or recover the aggregated vibrations so that each source of vibration can be correctly identified. In this paper, a comparison study is presented. Some widely used BSS and BE algorithms have been compared to evaluate their performance in the separation of mechanical vibrations. Both simulated sig- nals and real vibrations generated by industrial machines were used to verify the effectiveness of BSS and BE. Their deficiencies have also been identified and improvements are proposed in the paper, so that they could be effectively applied in the fault diagnosis of complex manufacturing machines.
TL;DR: In this article, a linear theory for the free and forced vibration problems of a slightly sagging planar inclined cable with a Tuned mass damper (TMD) installed is proposed using an analytical approach.
Abstract: A linear theory for the free and forced vibration problems of a slightly sagging planar inclined cable with a Tuned mass damper (TMD) installed is proposed using an analytical approach in this paper. Parameters of the cable such as cable geometry-elasticity parameter, cable internal damping, and cable inclination, parameters of the damper such as damper position and damper damping ratio, and parameters of the cable-damper proportion such as the mass ratio and the stiffness ratio, are taken into consideration in the derived equations. Special cases are discussed and some simpler models can be obtained. Complex solutions of the derived equations and their physical meaning are discussed. This paper serves as a theoretical base for the companion paper on the applications of TMDs to stay cables through a parametric approach.
TL;DR: In this article, the authors proposed a design for a precision positioning miniature walking robot using piezoelectric unimorph actuators, which achieved speeds of 586 cm/sec in forward and backward motion, respectively.
Abstract: This paper proposes a design for a precision positioning miniature walking robot using piezoelectric unimorph actuators The theoretical working equations of a uniform piezoelectric unimorph beam are derived based on the linear piezoelectric relations, Hamilton’s principle, and Euler-Bernoulli beam equation Themodal superposition method is used to determine the response of the forced transverse vibration of the beam under the effect of electrical signal inputs to the patterned piezoelectric element Two standing waves corresponding to the third and fourth bending vibration modes are utilized to achieve the bi-directional walking mechanism for a miniature positioning robot Design strategies and the fabrication method for the proposed walking robot are introduced Preliminary performance tests of the robot prototype are carried out successfully, and the robot achieves speeds of 586 cm/sec and 337 cm/sec in forward and backward motion, respectively
TL;DR: In this paper, the authors proposed a robust control algorithm for stabilization of a three-axis stabilized flexible spacecraft in the presence of model uncertainty, external disturbances and control input nonlinearities.
Abstract: This paper proposes a robust control algorithm for stabilization of a three-axis stabilized flexible spacecraft in the presence of model uncertainty, external disturbances and control input nonlinearities This control algorithm is based on a variable structure output feedback control design technique, and explicitly accounts for the control input nonlinearities in the stability analysis The proposed variable structure output feedback controller ensures the global reaching condition of the sliding mode of the spacecraft dynamics system Moreover, in the sliding mode, the investigated dynamic system still retains the robustness with respect to the uncertainties and disturbances it possesses for a system with linear input An attractive additional feature of the control method is that the structure of the controller is independent of the elastic mode dynamics of the spacecraft, since in practice the measurement of flexible modes is typically difficult or impractical It is also shown that an adaptive versi
TL;DR: In this article, an optimal Tuned Mass Damper (TMD) system is used to suppress the undesirable vibration in beams subjected to random excitations with peaked Power Spectral Densities (PSDs).
Abstract: Vibration suppression in beams subjected to random excitations with peaked Power Spectral Densities (PSDs) is studied in this paper. An optimal Tuned Mass Damper (TMD) system is used to suppress the undesirable vibration. The Timoshenko beam theory is applied to the beam model and the governing equations of motion are solved using the Galerkin method. Using the Sequential Quadratic Programming (SQP) method, the problem is solved to obtain the optimum values of the design variables (i.e. frequency ratio and the damping ratio) of the TMD system. Subsequently, a parametric study is carried out and the effects of the input parameters, such as the mass ratio, structural damping ratio, and the peak frequency of the random excitation on the design variables were investigated. The robustness of the optimal control system is also studied. Based on the PSD of the random excitation and using a Monte Carlo simulation algorithm, a set of numerical data for the excitation force is generated in the time domain and the e...
TL;DR: In this article, a parametric study is carried out to investigate the influence on the solutions, and thus the system modal damping and frequency, of the cable geometry-elasticity parameter, cable inclination, damper position, mass ratio, frequency ratio, and damper damping ratio.
Abstract: Based on the theoretical derivations of the free vibration problem for a cable-TMD system in the companion paper, a parametric study is carried out in the present paper to investigate the influence on the solutions, and thus the system modal damping and frequency, of the cable geometry-elasticity parameter, cable inclination, damper position, mass ratio, frequency ratio, damper damping ratio, and tuning mode. Emphasis is put on the system modal damping, as this is an important index of the performance of the TMD. The features and mechanisms of energy transfer and damping redistribution from the TMD to each mode of the cable-TMD system are also investigated and discussed.
TL;DR: In this paper, a neural-network controller is proposed for system identification and vibration suppression in a building structure with an active mass-damper, which is shown both numerically and experimentally that the controller can reliably identify system dynamics and effectively suppress vibration.
Abstract: PID and LQR/LQG controllers have are known to be ineffective for systems suffering from parameter variations and broadband excitations. This paper presents a neural-network design for system identification and vibration suppression in a building structure with an active mass-damper. It is shown both numerically and experimentally that the neural-network controller can reliably identify system dynamics and effectively suppress vibration. For the experimental model, which has a fundamental frequency of about 0.96 Hz, the steady-state vibration amplitude under resonance and random excitation are reduced by 80% and 70%, respectively. In addition, the peak-to-peak displacement under the 7.1 Richer scale Ji-Ji earthquake, Taiwan (Sep. 21, 1999) is effectively reduced by 80%. The controller is also shown to be robust to variations in system parameters.
TL;DR: In this paper, the authors studied energy pumping in two-and three-degrees-of-freedom systems of coupled linear and nonlinear oscillators and proposed a methodology for analyzing the transient response via time evolution of modulating functions.
Abstract: In this paper we study energy pumping phenomena in two- and three-degrees-of-freedom systems of coupled linear and nonlinear oscillators. Energy pumping is a passive, almost irreversible transfer of mechanical energy from the main substructure of the system to the light auxiliary attachment. The mechanism of energy pumping in the systems under consideration is resonance capture. Different designs of systems allowing energy pumping are examined both analytically and numerically. We propose a novel methodology for analyzing the transient response via time evolution of modulating functions. The analytical description of the process in terms of complex variables turns out to be in good agreement with the results of numerical simulations. We show that necessary conditions for applications of energy pumping can actually be provided. We show that it is possible to design a type of gear box (i.e. a system of various attachments connected with the main substructure in turn) providing more efficient energy transfer...
TL;DR: Time delay inevitably exists in active control systems and it may cause unsynchronized control forces that can not only degrade the performance of the control systems, but also induce instability of t...
Abstract: Time delay inevitably exists in active control systems. It may cause unsynchronized control forces that can not only degrade the performance of the control systems, but also induce instability of t...
TL;DR: In this article, the effects of substrate motions on the performance of microgyroscopes modeled as ring structures were discussed using the Extended Hamiltonian Principle (EHP) and the equations of motion of a ring m...
Abstract: This paper discusses the effects of substrate motions on the performance of microgyroscopes modeled as ring structures. Using the Extended Hamiltonian Principle, the equations of motion of a ring m...
TL;DR: In this paper, a rigid rotor supported on journal bearings using two-phase lubricants is studied and it is shown that discontinuity in the support forces arising out of contact with solid phase particles is observed.
Abstract: Solid phase particles in two-phase lubricants used in journal bearings undergo deformation in the bearing clearance space during large amplitude journal whirl. The orbital energy causing instability of the rotor shaft is drawn from the drive and it is proportional to the orbital area whereas energy dissipation offered by the fluid film is a path function. The balance of these two energies decides the stability of rotor-bearing system. In the first part of this paper, equivalent snubber springs have been used to represent contact with solid phase particles and purely elastic collision is modeled. It is analytically shown that any perturbation of a circular orbit increases dissipative work, which may entrain the response of an otherwise unstable system (i.e., without perturbation) to a stable orbit. In the second part of this paper, a rigid rotor supported on journal bearings using two-phase lubricants is studied and it is shown that discontinuity in the support forces arising out of contact with solid-phas...
TL;DR: In this article, an energy-based approach to analysis of the impact problem in three dimensional multi-legged robot locomotion is presented, which combines rigid and deformable body approaches, which come together naturally in a work-energy framework.
Abstract: An energy-based approach to analysis of the impact problem in three dimensional multi-legged robot locomotion is hereby presented. The goal is to combine rigid and deformable body approaches, which come together naturally in a work-energy framework. The rigid body approach is used to calculate the energy restituted after a foot impacts on the ground, and the ground and the foot are considered rigid bodies throughout the analysis. Then the flexible body approach is used to store the energy restituted to the system through the system’s compliance. The proposed hybrid approach can predict both rebound and non-rebound conditions for an energetic coefficient of restitution greater than zero. Zero tangential velocity (i.e., zero slip) in the impacting end effectors can be also predicted, a condition known as sticking. The article presents a method for determining whether the level of compliance in the system at a given configuration is adequate to insure a no-slip, no-rebound impact, with a focus on leg design.
TL;DR: In this paper, the dynamics and control of spinning tethers in elliptical orbits for payload rendezvous were studied and the required rendezvous conditions for the tether tip were derived for the case where the tether system center of mass and payload are in coplanar elliptic orbits.
Abstract: The dynamics and control of spinning tethers in elliptical orbits for payload rendezvous is studied. The required rendezvous conditions for the tether tip are derived for the case where the tether system center of mass and payload are in coplanar elliptic orbits. It is proposed that rendezvous control can be achieved by tracking the unique tip trajectory generated by propagating the rendezvous conditions backwards in time. The range of suitable combinations of tether system orbit eccentricity, tether length, and payload orbit eccentricity are studied numerically. It is shown that certain combinations of parameters lead to non-spinning capture requirements and slack tethers. Control of the tether motion through tether reeling is examined using a nonlinear model predictive control strategy. Numerical results illustrating the effectiveness of the controller are presented.
TL;DR: In this paper, the authors presented a 2 degree of freedom hardware in the loop simulator for the study of regenerative chatter in milling, where active damping was proposed as a strategy for control of chatter.
Abstract: This paper presents a 2 degree of freedom “Hardware in the Loop” mechatronic simulator for the study of regenerative chatter in milling. The main motivation behind the construction of the simulator is to propose active damping as a strategy for control of chatter in milling. A good comprehension of regenerative chatter in milling is essential for that purpose. Characterization of chatter in a real machining environment may be difficult, and the mechatronic simulator provides an alternative way to conduct investigations on chatter in milling in a laboratory environment, without conducting actual cutting tests. The simulator is found to realistically reproduce various kinds of bifurcation phenomena normally expected in milling operations. Active damping is then implemented on the system to investigate its effect on stability. It is shown experimentally that stability lobes are enhanced by the application of active damping, which fulfils the original objective of proposing active damping as a chatter stabili...
TL;DR: In this article, an integrated design of a controller and structure for the head positioning system was developed to solve the problem of negative effects of the primary resonant mode on the servo bandwidth.
Abstract: In head-positioning systems of hard disk drives, the negative effects of a primary resonant mode are serious problems for positioning accuracy. In order to improve positioning accuracy, the primary resonant frequency should be increased because the effects of the primary resonant mode limit the servo bandwidth. An integrated design of a controller and structure for the head positioning system was developed to solve this problem. We showed that the servo bandwidth is limited not only by the peak frequency of the primary resonance but are also its residue. The proposed method decreases the negative impact of the primary resonant mode through a newly designed modal shape, and increases the servo bandwidth without the addition of any sensors or actuators. The effectiveness of this method was verified by designing an actual servo control system and experimentally measuring its bandwidth, demonstrating that the method increases the servo bandwidth without increasing the production cost.
TL;DR: In this paper, the significance of spectral subtraction for the improvement of the sensitivity of scalar indicators (crest factor, kurtosis) within the application of conditional maintenance by vibratory analysis on ball bearings.
Abstract: In this paper we aim to show the significance of spectral subtraction for the improvement of the sensitivity of scalar indicators (crest factor, kurtosis) within the application of conditional maintenance by vibratory analysis on ball bearings. If we consider the case of a bearing in good condition of use, the distribution of the amplitudes in the signal is Gaussian. When the bearing is damaged, the appearance of spallings disturbs this signal, modifying this distribution. This modification goes through the presence of periodical impulses produced each time a rolling element meets a discontinuity on its way. Nevertheless, the presence of background noise induced by random impulse excitations can have an influence on the values of these temporal indicators. The de-noising of these signals by spectral subtraction in different frequency bands allows us to improve the sensitivity of these indicators and to increase the reliability of the diagnosis.
TL;DR: In this paper, the authors presented the mathematical modeling of micro-resonator dynamics and developed effective equations to study the electrically actuated micro-beam resonators, and the response of the system at steady-state conditions was developed by employing the averaging perturbation method on the nondimensionalized form of the equations.
Abstract: The thermal dependency of material characteristics is an important phenomenon affecting the motion of microresonator systems. Thermal phenomena introduce two main effects: damping due to internal friction, and softening due to the Young's modulus-temperature relationship. Based on reported theoretical and experimental results, we qualitatively model the thermal phenomenon utilizing a Lorentzian function to describe its effect on restoring and damping forces. We present the mathematical modeling of microresonator dynamics and develop effective equations to study the electrically actuated microbeam resonators. In order to study the thermal effects, a linearized model of the microelectromechanical system is adapted. The response of the system at steady-state conditions is developed by employing the averaging perturbation method on the non-dimensionalized form of the equations. Frequency response, resonant frequency and peak amplitude are examined for variation of the dynamic parameters involved.
TL;DR: In this article, the authors investigated the effect of a passive or semi-active tuned mass damper control mechanism on the performance of a suspension bridge over a normal bridge when subjected to wind loading.
Abstract: In this article, the along-wind and across-wind response of the suspended cables and the bridge deck response of a suspension bridge subjected to wind loading are studied. The mean wind direction is assumed to be perpendicular to the planes of the suspended cables. It is shown that the suspended cable, if constructed alone, will gallop in the across-wind direction when the mean wind speed exceeds a certain critical wind speed. Similarly the bridge deck, if constructed alone, will gallop when a critical wind speed is exceeded. The construction of a suspension bridge, through coupling the bridge deck with the suspended cables via vertical hangers, increases the critical wind speed at which galloping occurs. However, the increase in the critical wind speed of a suspension bridge over a normal bridge is not sufficient to prevent galloping at moderate wind speeds. This article investigates the use of a passive or semi-active tuned mass damper control mechanism to increase critical wind speed for a flexible sus...