Methods of determining the characteristics of vibration damping in elastic elements of systems with many degrees of freedom

1981 ◽  
Vol 13 (4) ◽  
pp. 500-507 ◽  
Author(s):  
V. V. Matveev ◽  
A. P. Zin'kovskii
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Damping ◽  
Elastic Elements

scholarly journals Computer model of electric drive of 1L100K conveying unit

2019 ◽  
Vol 134 ◽  
pp. 01012
Author(s):  
Denis Zolkin ◽  
Vadim Petrov
Keyword(s):  
Control System ◽  
Electric Drive ◽  
Ring System ◽  
Vibration Damping ◽  
Electromechanical System ◽  
Dynamic Loads ◽  
Belt Conveyor ◽  
Electric Drives ◽  
Belt Conveyors ◽  
Elastic Elements

The paper deals with the problems of vibration damping and limiting dynamic loads in the electromechanical system of a belt conveyor by means of an adjustable electric drive. A conveying unit is represented as a three-mass ring system, which corresponds to a conveying unit with cinematically closed tape. The development of the structure of the control system for electric drives of belt conveyors with limited dynamic loads in elastic elements will reduce the dynamic loads on the belt and therefore the wear of the belts. Conditions of damping of oscillations in electromechanical system of belt conveyors are defined.

scholarly journals Kane’s Formalism Used to the Vibration Analysis of a Wind Water Pump

Symmetry ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1030
Author(s):  
Gabriel Leonard Mitu ◽  
Eliza Chircan ◽  
Maria Luminita Scutaru ◽  
Sorin Vlase
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Element ◽  
Vibration Analysis ◽  
Degrees Of Freedom ◽  
Transmission Mechanism ◽  
Water Pump ◽  
The Finite Element Method ◽  
Lagrange’S Equation ◽  
Elastic Elements

The paper uses Kane’s formalism to study two degrees of freedom (DOF) mechanisms with elastic elements = employed in a wind water pump. This formalism represents an alternative, in our opinion, that is simpler and more economical to Lagrange’s equation, used mainly by researchers in this type of application. In the problems where the finite element method (FEM) is applied, Kane’s equations were not used at all. The automated computation causes it to be reconsidered in the case of mechanical systems with a high DOF. Analyzing the planar transmission mechanism, these equations were applied for the study of an elastic element. An analysis was then made of the results obtained for this type of water pump. The matrices coefficients of the obtained equations were symmetric or skew-symmetric.

Inertial Vibration Damping Control for a Flexible Base Manipulator

2002 ◽  
Author(s):  
Lynnane E. George ◽  
Wayne J. Book
Keyword(s):  
Performance Index ◽  
Degrees Of Freedom ◽  
Position Control ◽  
Joint Space ◽  
Vibration Damping ◽  
Degree Of Freedom ◽  
Inertia Effects ◽  
Inertial Interaction ◽  
Flexible Base ◽  
Three Degree Of Freedom

A rigid (micro) robot mounted serially to the tip of a long, flexible (macro) manipulator is often used to increase reach capability, but flexibility in the macromanipulator can interfere with positioning accuracy. A rigid manipulator attached to a flexible but unactuated base was used to study a scheme to achieve positioning of the micromanipulator combined with enhanced vibration damping of the base. Inertial interaction forces and torques acting between the robot and its base were modeled and studied to determine how to use them to damp the vibration. One issue is that there are locations in the workspace where the rigid robot loses its ability to create interactions in one or more degrees of freedom. These “inertial singularities” are functions of the rigid robot’s joint variables. A performance index was developed to predict the ability of the rigid robot to damp vibration and will help ensure the robot is operating in joint space configurations favorable for inertial damping. When the performance index is used along with the appropriate choice of feedback gains, the inertia effects, or those directly due to accelerating the robot’s links, have the greatest influence on the interactions. By commanding the robot link’s accelerations out of phase with the base velocity, vibration energy will be removed from the system. This signal is then added to the rigid robot’s position control signal. Simulations of a rigid three degree of freedom anthropomorphic robot mounted on a flexible base were developed and show the effectiveness of the control scheme. In addition, experimental results demonstrating two degree of freedom vibration damping are included.

scholarly journals Modal Control for Active Vibration Damping of Cable-Driven Parallel Robots

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Loïc Cuvillon ◽  
Xavier Weber ◽  
Jacques Gangloff
Keyword(s):  
Degrees Of Freedom ◽  
Transfer Functions ◽  
Parallel Robot ◽  
Vibration Damping ◽  
Parallel Robots ◽  
Robot Dynamics ◽  
End Effector ◽  
Active Vibration Damping ◽  
Active Vibration ◽  
High Dynamics

Abstract Cable-driven parallel robots are well suited for applications that require a very large workspace. Thanks to their lightweight moving parts, they can achieve high dynamics while remaining pretty safe for nearby human workers. Furthermore, their size depends only on the length of the cables; thus, their scale is almost totally decoupled from their cost. However, due to the cables, the stiffness is very low with respect to rigid link robots, inducing slowly damped oscillations of the end effector. Previous works have shown that those vibrations can be effectively damped by the winch actuators thanks to active vibration damping techniques. In this paper, a gain scheduling approach is proposed based on a linearized model of the robot dynamics. This model is projected in the modal space yielding six decoupled transfer functions for six degrees-of-freedom (DoFs) of a cable-driven parallel robot using thin cables. The stability of the proposed control law is analyzed for a static and a moving end effector. The proposed control algorithm is validated experimentally on an eight-cable suspended robot prototype.

scholarly journals SOME POSSIBILITIES OF DYNAMICAL VIBRATION DAMPING IN SYSTEMS WITH SEVERAL DEGREES OF FREEDOM

2017 ◽  
Vol 2017 (1) ◽  
pp. 290-301 ◽  
Author(s):  
Андрей Николаев ◽  
Andrey Nikolaev ◽  
Владимир Кашуба ◽  
Vladimir Kashuba ◽  
Сергей Елисеев ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Transfer Functions ◽  
Dynamic Properties ◽  
Vibration Damping ◽  
Structural Scheme ◽  
Oscillatory Systems ◽  
Dynamic Vibration ◽  
Dynamic Relation ◽  
Dynamic Blocking ◽  
The Mathematical Model

A method of dynamic vibration damping in mechanical oscillatory systems with several degrees of freedom is offered. The mathematical model of the system is represented in the form of structural scheme the equivalent in a dynamic relation to the automatic control system. The system contains device for con-verting the motion in the form of lever mechanisms containing focused additional masses. The possibilities of changing the dynamic properties of the system by using lever mechanisms and the additional ties in the form of gear connections of the elements system are shown. A method of constructing mathematical models and technology analysis of dynamic properties at kinematic excitation of system is proposed. The system of evaluation of the dynamic properties of the system in regimes of dynamic vibration damping simultaneously on two coordinates based on the use of transfer functions and analysis of structural scheme is offered. The results of computational modeling are given, confirming the manifestation the effects of dynamic blocking of external influences.

scholarly journals PIPELINE ROBOTS WITH ELASTIC ELEMENTS

Transport ◽  
2002 ◽  
Vol 17 (5) ◽  
pp. 177-181 ◽  
Author(s):  
Arvydas Matuliauskas ◽  
Bronislovas Spruogis
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Degrees Of Freedom ◽  
Vibration Exciter ◽  
Motion Equations ◽  
Two Degrees Of Freedom ◽  
One Dimensional ◽  
The Mathematical Model ◽  
Original Construction ◽  
Elastic Elements

In the article constructions of the pipeline robots with elastic elements are reviewed and the scheme of new original construction is presented. The mathematical models of a robot with one-dimensional vibration exciter with two degrees of freedom were developed and the equations of movement were formed and written. The mathematical model of the pipeline robot with circular elements is formed and its motion equations are presented.

A Global Simulation Model for Hermetic Reciprocating Compressors

1991 ◽  
Vol 113 (3) ◽  
pp. 395-400 ◽  
Author(s):  
M. A. de los Santos ◽  
S. Cardona ◽  
J. Sa´nchez-Reyes
Keyword(s):  
Theoretical Model ◽  
Simulation Model ◽  
Modal Analysis ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Discrete Element Model ◽  
Lagrange Equations ◽  
The Impact ◽  
Three Degrees Of Freedom ◽  
Elastic Elements

This article presents a simulation model for reciprocating hermetic compressors. The acoustical behavior of both admission and discharge circuits is analyzed by invoking the discrete element model. Cavities are considered as elastic elements and ducts as rigid elements with inertia according to this model. Reed valves are modeled as systems of three degrees of freedom, and are studied by using modal analysis. The percussive version of Lagrange equations is used to describe the impact between valves and stops or seats. Results from the theoretical model are checked with those experimentally obtained for a real compressor.

scholarly journals Vibration Damping Performances of Buildings with Moving Façades Under Harmonic Excitation

2020 ◽  
Author(s):  
Giulia Di Giovanni ◽  
Davide Bernardini
Keyword(s):  
Degrees Of Freedom ◽  
High Efficiency ◽  
External Surface ◽  
Harmonic Excitation ◽  
Vibration Damping ◽  
Vibration Absorbers ◽  
Tuned Mass Dampers ◽  
Mass Damper ◽  
Potential Applications ◽  
Potential Applicability

Abstract Background Façade technologies are in continuous evolution and the idea to realize buildings equipped with cladding systems capable to undergo significant displacements relatively to the main structure has been considered by many authors as an opportunity to improve their vibration performances. Method From a structural dynamics viewpoint, a building with a monolithic Moving Façade is essentially the same thing as a building with a Tuned Mass Damper. However, in the presence of excitations directly acting on the external surface of the building, there may be significant diferences of behavior. In this work, a first step towards a systematic comparison between the performances of buildings with Moving Façades and Tuned Mass Dampers is carried out in the simplest setting of 2 degrees of freedom modeling and harmonic excitation. Results Despite the deceptive simplicity of the setting, some of the aspects related to the potential applicability of moving façades to vibration damping and the correlated limitations are discussed and critically analyzed. The analyses show that, depending on the tuning of the system, monolithic Moving Façades could effectively act as vibration absorbers with a potentially high efficiency. However, it turns out that good performances could be realized at the price of extremely large displacements of the façade. The possibility to pursue potential applications of this type of systems seems therefore to be subordinated to the search of solutions to limit such displacements within functionally acceptable ranges.

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