Design of Vibration Absorbers for Step Motions and Step Disturbances

2005 ◽  
Vol 127 (1) ◽  
pp. 160-163 ◽  
Author(s):  
Joel Fortgang ◽  
William Singhose
Keyword(s):  
Time Constant ◽  
Mechanical Systems ◽  
Settling Time ◽  
Experimental Results ◽  
Performance Criteria ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Design Strategies ◽  
External Disturbances ◽  
Robotic Applications

Mechanical systems with flexible dynamics often suffer from vibration induced by changes in the reference command or from external disturbances. The technique of adding a vibration absorber has proven useful at eliminating vibrations from external disturbances and rotational imbalances. Traditionally, vibration absorbers have been designed for systems subject to sinusoidal or random excitations. Here the applicability of vibration absorbers to systems with steplike changes in the reference command or similar disturbances is studied. This type of motion is more common in robotic applications. Here absorbers are designed using two methods; the first technique uses a weighting on peak overshoot and settling time to allow tradeoffs between the two performance criteria. The second simpler method utilizes an eigenvalue technique to predict the time constant. Both of these techniques provide the possibility of significant improvement in settling time. The performance of this absorber design strategies is compared with previously proposed vibration absorbers and experimental results verify its utility.

Design of Vibration Absorbers for Step Motions and Step Disturbances

2001 ◽  
Author(s):  
Joel Fortgang ◽  
William Singhose
Keyword(s):  
Mechanical Systems ◽  
Oscillatory System ◽  
Settling Time ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
External Disturbances

Abstract Mechanical systems with flexible dynamics often suffer from vibration induced by changes in the reference command or from external disturbances. The technique of adding a secondary oscillatory system, called a vibration absorber, has proven useful at eliminating vibrations from external disturbances and rotational imbalances. Traditionally, vibration absorbers have been designed for systems subject to sinusoidal or random excitations. Here the applicability of vibration absorbers to systems with step changes in the reference command or similar disturbances is studied. The absorber can be designed with a weighting on peak overshoot and settling time, with the possibility of a nearly 90% improvement in settling time. The performance of this new absorber is compared with previously proposed vibration absorbers.

Concurrent Design of Vibration Absorbers and Input Shapers

2004 ◽  
Vol 127 (3) ◽  
pp. 329-335 ◽  
Author(s):  
Joel Fortgang ◽  
William Singhose
Keyword(s):  
Feedback Control ◽  
Computer Simulations ◽  
Performance Feedback ◽  
High Performance ◽  
Experimental Results ◽  
Input Shaping ◽  
Concurrent Design ◽  
Vibration Absorbers ◽  
External Disturbances

Systems with flexible dynamics often vibrate due to external disturbances, as well as from changes in the reference command. Feedback control is an obvious choice to deal with these vibrations, but in many cases, it is insufficient or difficult to implement. A technique that does not rely on high performance feedback control is presented here. It utilizes a combination of vibration absorbers and input shapers. Vibration absorbers have been used extensively to reduce vibration from sinusoidal disturbances, but they can also be implemented to reduce the response from transient functions. Input shaping has proven beneficial for reducing vibration that is caused by changes in the reference command. However, input shaping does not deal with vibration excited by external disturbances. In this paper, vibration absorbers and input shapers are designed sequentially and concurrently to reduce vibration from both the reference command and from external disturbances. The usefulness of this approach is demonstrated through computer simulations and experimental results.

Vibration Absorber and Harvester for Energy Efficient Structures

2013 ◽  
Author(s):  
A. Gonzalez-Buelga ◽  
L. Clare ◽  
S. A. Neild ◽  
A. Cammarano ◽  
D. J. Wagg ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Vibration Suppression ◽  
Experimental Results ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Tuned Mass Dampers ◽  
Sufficient Energy ◽  
Self Tuning ◽  
Self Powered

Most work has been conducted on vibration absorbers, such as tuned mass dampers, where significant energy is extracted from a structure. We investigate the concept of recovering some of this energy electrically. We present experimental results from a vibration absorber/harvester. Our results suggest that sufficient energy might be harvested such the device can be self tuning and self powered to optimize vibration suppression.

Dynamic Vibration Absorber Optimal Design With Emphasis on Complete Machine Dynamics Modelling

2008 ◽  
Author(s):  
Bohdan M. Diveyev ◽  
Zinovij A. Stotsko
Keyword(s):  
Optimal Design ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Rotating Machines ◽  
Dynamic Vibration Absorber ◽  
New Methods ◽  
Dynamic Vibration ◽  
Methods Development ◽  
Dynamic Vibration Absorbers ◽  
Dynamics Modelling

The main aim of this paper is improved dynamic vibration absorbers design with taking into account complex rotating machines dynamic The is considered for the complex vibroexitated constructions. Methods of decomposition and the numerical schemes synthesis are considered on the basis of new methods of modal methods. Development of of complicated machines and buildings in view of their interaction with system of dynamic vibration absorbers is under discussion.

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.

An Algorithm for Modeling the Covalent Triazine-Based Frameworks

2019 ◽  
Vol 956 ◽  
pp. 212-217
Author(s):  
Ce Song ◽  
Zhao Liang Meng ◽  
Jin Yan Wang ◽  
Fang Yuan Hu ◽  
Xi Gao Jian
Keyword(s):  
Theoretical Model ◽  
Pore Size ◽  
Structural Properties ◽  
Experimental Results ◽  
Size Distributions ◽  
Design Strategies ◽  
Surface Areas ◽  
Pore Size Distributions ◽  
Amorphous Structures ◽  
Acceptable Consistency

An algorithm for generating the representative structures of covalent triazine-based frameworks (CTFs) is proposed, and examined by being applied to the framework synthesized by the trimerization of dicyanobenzene. The algorithm is validated by the comparison between the calculated and experimental results of the structural properties such as surface areas and pore size distributions, which shows acceptable consistency. Moreover, the presented modeling approach can be expected for more extensive use for other CTFs. Thus the simulated atomistic strucutures produced from the modeling method can improve the understanding for amorphous structures of the CTFs which have already been developed, as well as predict the theoretical model of new CTFs, and provide useful design strategies for the future experimental efforts.

Design and Analysis of Micro Plastic Heat Exchanger

2012 ◽  
Vol 562-564 ◽  
pp. 1776-1779
Author(s):  
Yue Han ◽  
Heng Zhi Cai ◽  
Ya Jun Zhang ◽  
Da Ming Wu ◽  
Xin Liang Wang
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Chemical Engineering ◽  
Mechanical Systems ◽  
Experimental Results ◽  
Micro Electro Mechanical Systems ◽  
Micro Heat Exchanger ◽  
Simulation And Experiment ◽  
Energy Engineering

The heat exchanger is widely used in energy engineering, chemical engineering etc. And with development of the MEMS (Micro Electro Mechanical Systems), many researchers are interested in the micro heat exchanger. In this paper, the micro plastic heat exchangers are manufactured by modified PPS. A heat exchanger with polypropylene (PP) is also made for comparison. Simulation and experiment are carried out to determine the thermal performance of the micro plastic heat exchangers. The experimental results are compared with that of simulation. The results show the performance of the micro plastic heat exchanger is very close to that of metal heat exchanger with the same dimension.

Using a Vibration Absorber to Suppress Chatter Vibration in Turning Process With a Worn Tool

2009 ◽  
Author(s):  
Hamed Moradi ◽  
Firooz Bakhtiari-Nejad ◽  
Mohammad R. Movahhedi
Keyword(s):  
Transmission Lines ◽  
Gas Turbines ◽  
Block Diagram ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Turning Process ◽  
Electrical Transmission ◽  
Chatter Suppression ◽  
Orthogonal Turning ◽  
Dynamic Vibration Absorbers

Dynamic vibration absorbers are used as semi-active controllers to reduce the undesirable vibrations in many applications such as electrical transmission lines, helicopters, gas turbines, engines, bridges and etc. One type of these absorbers is tunable vibration absorber (TVA). In this paper, regenerative chatter in an orthogonal turning process is suppressed using a (TVA). It is shown that TVA can modify the frequency response function of the cutting tool so as to improve cutting stability in turning process. In addition, tool wear is an important factor which works as a positive damping and helps the chatter suppression beside exertion of the TVA. Finally, using the SIMULINK Toolbox of MATLAB, the analog simulated block diagram of the problem is developed. The advantage of this simulation is that, one can analyze the effect of other types of excitations such as step, ramp, etc on the absorbed system.

Controllable, High Force Amplification Using Elastic Cable Capstans

2012 ◽  
Author(s):  
Gray C. Thomas ◽  
Clayton C. Gimenez ◽  
Erica D. Chin ◽  
Andrew P. Carmedelle ◽  
Aaron M. Hoover
Keyword(s):  
Dynamic Performance ◽  
Experimental Results ◽  
Rotating Drum ◽  
Experimental Characterization ◽  
Experimental Apparatus ◽  
Linear Force ◽  
Low Torque ◽  
Robotic Applications

This paper presents the design and experimental characterization of a continuously variable linear force amplifier based on the theory of capstans. In contrast to traditional capstan amplifiers, the design presented here uses an elastic cable, enabling a control actuator to not only continuously clutch output to a rotating drum but also passively declutch by releasing tension. Our experimental results demonstrate successful declutching at all force amplification ratios up to the limit of our experimental apparatus, 21 — significantly higher than previously published values. A system of distributed capstan amplifiers driven by a central torque source with cable engagement switched by lightweight, low torque actuators has potential to reduce the mass of distal actuators and enable more dynamic performance in robotic applications.

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