scholarly journals Dynamical Performances of a Vibration Absorber for Continuous Structure considering Time-Delay Coupling

2016 ◽  
Vol 2016 ◽  
pp. 1-15
Author(s):  
Xiuting Sun ◽  
Youshuo Song
Keyword(s):  
Time Delay ◽  
Vibration Suppression ◽  
Vibration Absorber ◽  
Engineering Practice ◽  
Vibration Absorbers ◽  
Low Frequencies ◽  
Coupling System ◽  
Coupling Time ◽  
The Stability ◽  
And Control

The nonlinear effect incurred by time delay in vibration control is investigated in this study via a vibration absorber coupled with a continuous beam structure. The stability of the vibration absorber coupled structure system with time-delay coupling is firstly studied, which provides a general guideline for the potential time delay to be introduced to the system. Then it is shown that there is a specific region for the time delay which can bring bifurcation modes to the dynamic response of the coupling system, and the vibration energy at low frequencies can be transferred or absorbed due to the bifurcation mode and the vibration in the corresponding frequency range is thus suppressed. The nonlinear mechanism of this vibration suppression incurred by the coupling time delay is discussed in detail, which provides a novel and alternative approach to the analysis, design, and control of vibration absorbers in engineering practice.

Design and control of adaptive vibration absorber for multimode structure

2019 ◽  
Vol 30 (7) ◽  
pp. 1043-1052 ◽  
Author(s):  
Jin-Siang Shaw ◽  
Cheng-An Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Fuzzy Logic Controller ◽  
Vibration Suppression ◽  
Experimental Testing ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Vibration Absorption ◽  
Resonant Modes ◽  
And Control

In this study, we used two tunable vibration absorbers composed of shape memory alloy to reduce vibration of a platform structure. The natural frequency of the shape memory alloy absorber can be tuned online using a fuzzy logic controller to change the axial force of the shape memory alloy wires through phase transformation. In addition, we employed the finite element method to analyze the dynamic characteristics of the multimode platform structure and to evaluate the effectiveness of the shape memory alloy vibration absorber in terms of platform vibration attenuation. Experimental testing of the platform structure was conducted to verify its modal characteristics. By setting the two shape memory alloy tunable vibration absorbers on two adjacent sides of the platform at 90 degrees to each other and offset from the platform’s center axes, it is shown that all six modes can be covered for vibration absorption. The experiments show that the vibration due to all six mode modal excitations can be attenuated by more than 7.49 dB using the shape memory alloy tunable vibration absorber. Specifically, at the fourth, fifth, and sixth resonant modes, an average of 16.68 dB vibration suppression is observed. Overall, an average of 12.69 dB vibration suppression is achieved for resonant excitation of the entire platform structure when using the designed shape memory alloy tunable vibration absorber.

Design of a turning cutting tool with large length–diameter ratio based on three-element type vibration absorber

2020 ◽  
Vol 234 (6-7) ◽  
pp. 1032-1043
Author(s):  
Yiqing Yang ◽  
Haoyang Gao ◽  
Wenshuo Ma ◽  
Qiang Liu
Keyword(s):  
Frequency Response ◽  
Cutting Tool ◽  
Vibration Suppression ◽  
Diameter Ratio ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Target Mode ◽  
Large Length ◽  
Element Type ◽  
Structural Parts

The vibration absorber has been effective in vibration control. From the demand of manufacturing structural parts with a deep hole, the design of a turning cutting tool with large length–diameter ratio is presented. An analytical approach of acquiring frequency response of primary structure equipped with typical single-degree-of-freedom vibration absorbers is formulated, and background modes are incorporated with the purpose of achieving an accurate tuning of vibration absorber. Specifically, the three-element type is investigated as the damping element of the vibration absorber embedded in the cutting tool contributes to the stiffness, although it demonstrates medium performance of vibration suppression according to non-dimensional analysis. The experimentally tuned frequency response function of the turning cutting tool with three-element vibration absorber achieves 87.1% reduction on the amplitude of the target mode. Finally, several configurations of internal turning operations are carried out to validate the design of the vibration absorber.

scholarly journals Full Characterization of Act-and-wait Control for First-order Unstable Lag Processes

2010 ◽  
Vol 16 (7-8) ◽  
pp. 1209-1233 ◽  
Author(s):  
T. Insperger ◽  
P. Wahi ◽  
A. Colombo ◽  
G. Stépán ◽  
M. Di Bernardo ◽  
...  
Keyword(s):  
Time Delay ◽  
Feedback Systems ◽  
Periodic Control ◽  
First Order ◽  
Full Characterization ◽  
The Stability ◽  
And Control ◽  
Time Periodic ◽  
Special Case

Act-and-wait control is a special case of time-periodic control for systems with feedback delay, where the control gains are periodically switched on and off in order to stabilize otherwise unstable systems. The stability of feedback systems in the presence of time delay is a challenging problem. In this paper, we show that the act-and-wait type time-periodic control can always provide deadbeat control for first-order unstable lag processes with any (large but) fixed value of the time delay in the feedback loop. A full characterization of this act-and-wait controller with respect to the system and control parameters is given based on performance and robustness against disturbances.

scholarly journals Digital control of cable vibration with time delay

2020 ◽  
Author(s):  
László E. Kollár
Keyword(s):  
Time Delay ◽  
Active Control ◽  
Digital Control ◽  
Vibration Amplitude ◽  
Excitation Frequency ◽  
Vibration Absorber ◽  
Wind Effect ◽  
Cable Vibration ◽  
The Stability ◽  
Short Time

Abstract A simplified model for active control of vibration of a suspended cable is proposed. The model is constructed so that it considers the dynamic characteristics of the cable at the location where a vibration absorber is attached together with the absorber itself. The control is applicable for attenuating high-frequency, low-amplitude cable vibration due to periodic excitation that may model the wind effect. The methodology to choose control parameters is based on the dynamics of the vibration absorber and the stability analysis of the controlled system. The model takes into account the time delay that is always present in digital control due to sampling. Results reveal that the application of active control reduces vibration amplitude significantly provided that samples are taken in short time intervals. Increasing time delay reduces the effects of control and above a critical value, the vibration amplitude becomes even greater than without control. The importance of time delay grows with increasing excitation frequency, which means a limitation of the application of the control methodology developed. This limitation concerns the highest excitation frequencies.

Active Vibration Suppression With Time Delayed Feedback

2003 ◽  
Vol 125 (3) ◽  
pp. 384-388 ◽  
Author(s):  
Rifat Sipahi ◽  
Nejat Olgac
Keyword(s):  
Stability Analysis ◽  
Time Delay ◽  
Vibration Suppression ◽  
Linear Time ◽  
Direct Method ◽  
System Stability ◽  
Delayed Systems ◽  
Active Vibration Suppression ◽  
Active Vibration ◽  
The Stability

Various active vibration suppression techniques, which use feedback control, are implemented on the structures. In real application, time delay can not be avoided especially in the feedback line of the actively controlled systems. The effects of the delay have to be thoroughly understood from the perspective of system stability and the performance of the controlled system. Often used control laws are developed without taking the delay into account. They fulfill the design requirements when free of delay. As unavoidable delay appears, however, the performance of the control changes. This work addresses the stability analysis of such dynamics as the control law remains unchanged but carries the effect of feedback time-delay, which can be varied. For this stability analysis along the delay axis, we follow up a recent methodology of the authors, the Direct Method (DM), which offers a unique and unprecedented treatment of a general class of linear time invariant time delayed systems (LTI-TDS). We discuss the underlying features and the highlights of the method briefly. Over an example vibration suppression setting we declare the stability intervals of the dynamics in time delay space using the DM. Having assessed the stability, we then look at the frequency response characteristics of the system as performance indications.

scholarly journals ANALYZE THE EFFECT OF TIME DELAY ON THE STABILITY OF HYBRID ACTIVE POWER FILTER

2022 ◽  
Vol 36 (06) ◽  
Author(s):  
CHAU MINH THUYEN
Keyword(s):  
Time Delay ◽  
Active Power Filter ◽  
Active Power ◽  
Practical Significance ◽  
Stable Domain ◽  
Power Filter ◽  
Hybrid Active Power Filter ◽  
The Stability ◽  
And Control ◽  
The Mathematical Model

Hybrid Active Power Filter (HAPF) has highly effective in improving the power quality of power system. In this paper, a stable analysis of HAPF considering the time delay was made. The mathematical model of HAPF with time delay has been established. Based on that, the stable domain of the HAPF parameters was determined based on the Routh’s stability standard. Simulation results based on Matlab software have shown that: time delay has a marked impact on the stability of the HAPF system. This research has practical significance in the design and control of HAPF in real system.

Sequential design of two orthogonal dynamic vibration absorbers in a pendulum based on stability maximization

2012 ◽  
Vol 226 (11) ◽  
pp. 2645-2655 ◽  
Author(s):  
LD Viet
Keyword(s):  
Tangential Direction ◽  
Normal Direction ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Dynamic Vibration Absorber ◽  
Linear Dynamic ◽  
Dynamic Vibration ◽  
Dynamic Vibration Absorbers ◽  
Small Benefit ◽  
The Stability

A dynamic vibration absorber moving in the tangential or in the normal direction of a pendulum’s orbit can reduce the free vibration of the pendulum. This article discusses the problem of a pendulum structure attached with two dynamic vibration absorbers moving orthogonally at the same time. The analytical optimization is proposed to be done in two steps, in which the parameters of the linear dynamic vibration absorber moving in tangential direction and the non-linear dynamic vibration absorber moving in normal direction are chosen sequentially based on the stability maximization criterion. The analytical analysis shows that the two-dynamic vibration absorber scheme has small benefit in comparison with the single-dynamic vibration absorber scheme. The analytical conclusions are verified by numerical calculations. Although the conclusion of the article is unexpected, it is important in practice because the two-dynamic vibration absorber arrangement can be excluded in the design.

scholarly journals Vibration Suppression and Energy Harvesting with a Non-traditional Vibration Absorber: Transient Responses

Vibration ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 105-122
Author(s):  
Miao Yuan ◽  
Kefu Liu
Keyword(s):  
Computer Simulation ◽  
Energy Harvesting ◽  
Vibration Suppression ◽  
Frequency Tuning ◽  
Damping Ratio ◽  
Load Resistance ◽  
Vibration Absorber ◽  
Transient Responses ◽  
Tuning Ratio ◽  
The Stability

This paper focuses on vibration suppression and energy harvesting using a non-traditional vibration absorber referred to as model B. Unlike the traditional vibration absorber, model B has its damper connected between the absorber mass and ground. The apparatus used in the study consists of a cantilever beam attached by a mass at its free end and an electromagnetic energy harvester. The frequency tuning is achieved by varying the beam length while the damping tuning is realized by varying the harvester load resistance. The question addressed is how to achieve the best performance under transient responses. The optimum tuning condition for vibration suppression is based on the Stability Maximization Criterion (SMC). The performance of energy harvesting is measured by the percentage of the harvested energy to the input energy. A computer simulation is conducted. The results validate the optimum parameters derived by the SMC. There is a trade-off between vibration suppression and energy harvesting within the realistic ranges of the frequency tuning ratio and damping ratio. A multi-objective optimization is conducted. The results provide a guideline for obtaining a balanced performance. An experimental study is carried out. The results verify the main findings from the computer simulation. This study shows that the developed apparatus is capable of achieving simultaneous vibration suppression and energy harvesting under transient responses.

scholarly journals Friction-Induced Vibration Suppression via the Tuned Mass Damper: Optimal Tuning Strategy

Lubricants ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 100
Author(s):  
Jia Lin Hu ◽  
Giuseppe Habib
Keyword(s):  
Vibration Suppression ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Dynamic Vibration Absorber ◽  
Restoring Force ◽  
Stick Slip ◽  
Optimal Tuning ◽  
Dynamic Vibration ◽  
Tuning Strategy ◽  
Friction Induced Vibration

Friction-induced vibrations are a significant problem in various engineering applications, while dynamic vibration absorbers are an economical and effective tool for suppressing various kinds of vibrations. In this study, the archetypal mass-on-moving-belt model with an attached dynamic vibration absorber was considered. By adopting an analytical procedure, the optimal tuning of the absorber’s parameters was defined. Furthermore, the bifurcations occurring at the loss of stability were analytically investigated; this analysis illustrated that a properly chosen nonlinearity in the absorber’s stiffness permits controlling the supercritical or subcritical character of the bifurcation. However, a numerical analysis of the system’s dynamics, despite confirming the analytical results, also illustrated that the system’s global behavior is only slightly affected by the bifurcation character. Indeed, a dynamic vibration absorber possessing a perfectly linear restoring force function seems to provide the optimal performance; namely, it minimizes the velocity range for which stick–slip oscillations exists.

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