Relative Stability Analysis for Vibration Absorbers With Multiple Delayed Feedback

2000 ◽  
Author(s):  
Chang Huang ◽  
Nejat Olgac
Keyword(s):  
Relative Stability ◽  
Time Delays ◽  
A Priori ◽  
System Stability ◽  
Vibration Absorbers ◽  
Vibration Absorption ◽  
Stability Chart ◽  
On Line ◽  
Active Vibration ◽  
Operating Points

Abstract A novel tuning methodology for active vibration absorption is discussed. The underlying proposition is to use partial state feedback with multiple unrelated time delays. The objective of this tuning is to combat excitation forces with multiple frequencies, which are time varying. It is shown that the required control parameters can be evaluated on-line rather rapidly. The system stability aspect however, needs to be resolved a priori to the control actuation. This is the challenge facing this procedure due to the presence of multiple (and mostly “unrelated”) time delays. A new stability assessment methodology, the Directional Stability Chart method, is presented. The outcome of this procedure is used to determine the local stability levels and preferred operating zones in the domain of the multiple excitation frequencies. The method is also expanded to assess the relative stability level of the tuned absorber. Example case is taken from a PZT actuated active absorber. Desirability of the operating points are compared based on the relative stability levels, and the observations are verified by simulations.

scholarly journals On-Line Modal Parameter Identification Applied to Linear and Nonlinear Vibration Absorbers

Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 119
Author(s):  
Luis Gerardo Trujillo-Franco ◽  
Gerardo Silva-Navarro ◽  
Francisco Beltran-Carbajal ◽  
Eduardo Campos-Mercado ◽  
Hugo Francisco Abundis-Fong
Keyword(s):  
Nonlinear Dynamic ◽  
Degrees Of Freedom ◽  
Flexible Structure ◽  
Primary System ◽  
Vibration Absorbers ◽  
Modal Parameter ◽  
Vibration Absorption ◽  
Dynamic Vibration ◽  
On Line ◽  
Linear And Nonlinear

A solution of the vibration attention problem on a flexible structure from a dynamic vibration absorption perspective is experimentally and numerically studied in this article. Linear and nonlinear dynamic vibration absorbers are properly implemented on a primary structure of n degrees of freedom through a modal decomposition analysis and using the tuning condition when the primary system has one single degree of freedom. A time-domain algebraic identification scheme for on-line modal parameter estimation of flexible structures is presented. A fast frequency estimation of harmonic excitation force is also obtained. A Hilbert transform analysis of the frequency response function for the case of nonlinear dynamic vibration absorption is introduced. In this way, influence of this particular passive nonlinear control device on system dynamic response can be determined. The proposed approach is validated on an harmonically perturbed building-like structure, which is discretized in a finite number of degrees of freedom. The flexible structure is subjected to resonant operational conditions, and coupled to a pendulum vibration absorber configured as a tuned mass damper as well as an autoparametric system.

scholarly journals Design of Active Vibration Absorbers Using On-Line Estimation of Parameters and Signals

10.5772/24993 ◽  
2011 ◽  
Author(s):  
Francisco Beltran-Carbajal ◽  
Gerardo Silva-Navarro ◽  
Benjamin Vazquez-Gonzalez ◽  
Esteban Chavez-Conde
Keyword(s):  
Vibration Absorbers ◽  
Estimation Of Parameters ◽  
On Line ◽  
Active Vibration

Experimental Comparison of Delayed Resonator and PD Controlled Vibration Absorbers Using Electromagnetic Actuators

1998 ◽  
Vol 122 (3) ◽  
pp. 514-520 ◽  
Author(s):  
Hakan Elmali ◽  
Mark Renzulli ◽  
Nejat Olgac
Keyword(s):  
Sliding Mode ◽  
Experimental Comparison ◽  
Vibration Absorbers ◽  
Electromagnetic Actuators ◽  
Single Degree Of Freedom ◽  
Actuator Dynamics ◽  
Vibration Absorption ◽  
Feedback Structure ◽  
Active Vibration ◽  
Absorption Technique

The Delayed Resonator (DR) is a recent active vibration absorption technique which uses time delayed position feedback generating ideal resonance feature in a passive vibration absorber. This objective can also be achieved using proportional and derivative (PD) control as well as other more sophisticated routines such as LQR, sliding mode control. In this paper, DR technique is compared with PD, a widely adopted control strategy. Actuator dynamics is taken into account in analyzing the system. An analytical comparison is presented which is followed by an experimental validation of the findings using a single-degree-of-freedom primary structure and an absorber with electromagnetic actuator. Both analytical and experimental results show that the DR and PD implementations can be equally effective in suppressing undesired oscillations. The latter, however, requires a velocity observer, which is an additional complexity beyond the DR feedback structure. [S0022-0434(00)02203-6]

Active Vibration Absorption Using Delayed Resonator With Relative Position Measurement

1997 ◽  
Vol 119 (1) ◽  
pp. 131-136 ◽  
Author(s):  
N. Olgac ◽  
M. Hosek
Keyword(s):  
Relative Position ◽  
Primary Structure ◽  
System Stability ◽  
Trivial Extension ◽  
Control Force ◽  
Position Measurement ◽  
Harmonic Force ◽  
Stability Range ◽  
Vibration Absorption ◽  
Active Vibration

A novel active vibration absorption technique, the Delayed Resonator, has been introduced recently as a unique way of suppressing undesired oscillations. It suggests a control force on a mass-spring-damper absorber in the form of a proportional position feedback with a time delay. Its strengths consist of extremely simple implementation of the control algorithm, total vibration suppression of the primary structure against a harmonic force excitation and full effectiveness of the absorber in a semi-infinite range of disturbance frequency, achieved by real-time tuning. All this development work was done using the absolute displacements of the absorber in the feedback. These measurements, however, may be difficult to obtain and for some applications impossible. This paper deals with the operating and design repercussions caused by the substituting of an easier measurement: the relative motion of the absorber with respect to the primary structure. Although the proposition sounds like a trivial extension to the prior work it gives rise to important concerns such as system stability. Theoretical foundations for the Delayed Resonator (DR) are briefly recapitulated and its implementation on a single-degree-of-freedom primary structure disturbed by a harmonic force is discussed utilizing both absolute and relative position measurement of absorber mass. Methods for stability range analysis and transient behavior are presented as design tools. Properties observed for the same system with these two different feedbacks are compared. Another important advantage of the relative position feature is is to decouple the operation of the absorber from the primary structure entirely.

Further results on output-feedback stabilization of stochastic upper-triangular systems with state and input time-delays

2017 ◽  
Vol 40 (7) ◽  
pp. 2408-2415 ◽  
Author(s):  
Liang Liu ◽  
Shengyuan Xu ◽  
Xuejun Xie ◽  
Bing Xiao
Keyword(s):  
Output Feedback ◽  
Time Delays ◽  
Delay System ◽  
Feedback Stabilization ◽  
System Stability ◽  
Output Feedback Stabilization ◽  
Triangular Systems ◽  
Reduced Order Observer ◽  
Input Time ◽  
Stochastic Time

Based on stochastic time-delay system stability criterion and a homogeneous domination approach, the output-feedback stabilization problem for a class of more general stochastic upper-triangular systems with state and input time-delays has been solved in this paper. Firstly, the initial system is changed into an equivalent one with a designed scalar by introducing a set of coordinate transformations. After that, by designing an implementable homogeneous reduced-order observer, and tactfully selecting a suitable Lyapunov–Krasoviskii functional and a low gain scale, a delay-independent output-feedback controller is explicitly constructed. Finally, the globally asymptotically stability in probability of the closed-loop system is ensured by rigorous proof. The simulation results demonstrate the efficiency of the proposed design scheme.

Active Vibration Absorption Using Delayed Resonator With Relative Position Measurement

1995 ◽  
Author(s):  
Nejat Olgac ◽  
Martin Hosek
Keyword(s):  
Relative Position ◽  
Primary Structure ◽  
Vibration Suppression ◽  
Control Force ◽  
Range Analysis ◽  
Position Measurement ◽  
Harmonic Force ◽  
Stability Range ◽  
Vibration Absorption ◽  
Active Vibration

Abstract A novel active vibration absorption technique, the Delayed Resonator, has been introduced recently as a unique way of suppressing undesired oscillations. It suggests a control force on a mass-spring-damper absorber in the form of a proportional position feedback with a time delay. Its strengths consist of extremely simple implementation of the control algorithm, total vibration suppression of the primary structure against a harmonic force excitation and full effectiveness of the absorber in a semi-infinite range of disturbance frequency, achieved by real-time tuning. All this development work was done using the absolute displacements of the absorber in the feedback. These displacement measurements may be difficult to obtain and for some applications impossible. This paper deals with a substitute and easier measurement: the relative motion of the absorber with respect to the primary structure. Theoretical foundations for the Delayed Resonator (DR) are briefly recapitulated and its implementation on a single-degree-of-freedom primary structure disturbed by a harmonic force is introduced utilizing both absolute and relative position measurement of absorber mass. Methods for stability range analysis and transient behavior are presented. Properties acquired for the same system with these two different feedback are compared. Relative position measurement case is found to be more advantageous in most applications of the Delayed Resonator method.

Payload noise suppression using distributed active vibration absorbers

2002 ◽  
Author(s):  
Stephen D. O'Regan ◽  
Bart Burkewitz ◽  
Christopher Fuller ◽  
Steven A. Lane ◽  
Marty Johnson
Keyword(s):  
Noise Suppression ◽  
Vibration Absorbers ◽  
Active Vibration

scholarly journals Investigation On The Optimal Tunable Bi-Stable Clustered Energy Conversion Inspired Dynamic Vibration Absorbers: A Theoretical Study

2021 ◽  
Author(s):  
Xingbao Huang ◽  
Xiao Zhang ◽  
Bintang Yang
Keyword(s):  
Energy Conversion ◽  
Vibration Control ◽  
Conversion Efficiency ◽  
Energy Conversion Efficiency ◽  
Vibration Absorbers ◽  
Input Energy ◽  
Mass Ratio ◽  
Vibration Absorption ◽  
Dynamic Vibration Absorbers ◽  
Conversion Performance

Abstract This paper introduces an energy conversion inspired vibration control methodology and presents a representative prototype of tunable bi-stable energy converters. This work is concerned on improving the vibration absorption and energy conversion performance of tunable bi-stable clustered energy conversion inspired dynamic vibration absorbers (EC-DVAs). The deterministic parametric analysis of the energy transfer performance of clustered EC-DVAs is conducted. Firstly, nonlinear vibration behaviors including transient energy transfer and snap-through motions are studied, and then effects of EC-DVA number on vibration control is investigated. Furthermore, the optimal computation based on adjusting the length ratio (namely bi-stable potential barrier height) is developed to obtain the maximum energy conversion efficiency of clustered EC-DVAs and the minimum residual kinetic energy of the primary system considering different number of clustered EC-DVAs. Moreover, the optimal calculation based on optimal EC-DVA number is also developed to achieve the most excellent vibration absorption and energy conversion performance. Finally, the optimal calculation based on optimal mass ratio is conducted. Numerical simulations show that when the total mass ratio is constant the snap-through motions of each EC-DVA depend remarkably on EC-DVA number; the energy conversion efficiency and residual kinetic energy after dynamic length ratio optimization is independent on ambient input energy and EC-DVA number; The energy conversion efficiency and vibration absorption performance based on optimal EC-DVA number maintain high efficiency and stable when the ambient input energy or the potential energy of clustered EC-DVAs varies. The optimal mass ratio is large when the system’s potential barrier is too large and the ambient input energy is small. Therefore, the presented tunable bi-stable system of clustered EC-DVAs with appropriate bi-stable potential function and proposed optimization strategies is a potential alternative for vibration control of mechanical components exposed to varying impulses.

Do Common User Interface Design Patterns Improve Navigation?

2002 ◽  
Vol 46 (14) ◽  
pp. 1315-1319 ◽  
Author(s):  
Carlos A. Maldonado ◽  
Marc L. Jlesnick
Keyword(s):  
Web Sites ◽  
Interface Design ◽  
Design Patterns ◽  
Performance Metrics ◽  
Statistical Significance ◽  
A Priori ◽  
Improve Performance ◽  
Subjective Preference ◽  
On Line ◽  
Quantitative Performance

The Internet has become a growing channel for consumer purchases. Half of all U.S. consumers made at least one purchase on-line in 2001. However, many consumers report frustration with the lack of support for navigation within many Internet retailers' web sites. Several design patterns have been suggested to overcome these limitations, such as expanded hierarchies and breadcrumbs. This study investigated the effects of these design patterns on users' quantitative performance and subjective preference for ecommerce web sites. Expanded hierarchies, a design pattern that is commonly used by many retail web sites, degraded all of the performance metrics assessed in the study. Users required more time, made more errors, used more clicks, and had lower satisfaction scores for sites designed with expanded hierarchies. The results for breadcrumbs suggest that they may improve performance. The inclusion of breadcrumbs reduced the number of clicks required by users to complete the tasks, but other performance metrics did not reach statistical significance. The results indicate that design patterns that are believed to improve performance a priori may not yield the results expected.

Two-Step Process Identification With Correlation Analysis and Least-Squares Parameter Estimation

1974 ◽  
Vol 96 (4) ◽  
pp. 426-432 ◽  
Author(s):  
R. Isermann ◽  
U. Bauer
Keyword(s):  
Correlation Analysis ◽  
Process Model ◽  
A Priori ◽  
Industrial Process ◽  
Computation Time ◽  
Small Computer ◽  
Nonparametric Model ◽  
Identification Method ◽  
On Line ◽  
Process Computer

An identification method is described which first identifies a linear nonparametric model (crosscorrelation function, impulse response) by correlation analysis and then estimates the parameters of a parametric model (discrete transfer function) and also includes a method for the detection of the model order and the time delay. The performance, the computational expense and the overall reliability of this method is compared with five other identification methods. This two-step identification method, which can be applied off-line or on-line, is especially suited to identification by process computers, since it has the properties: Little a priori knowledge about the structure of the process model; very short computation time; small computer storage; no initial values of matrices and parameters are necessary and no divergence is possible for the on-line version. Results of an on-line identification of an industrial process with a process computer are shown.

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