scholarly journals INERTIAL COUPLING IMPACT UPON OSCILLATION AMPLITUDE DISTRIBUTION OF WORK APPARATUS OF TECHNOLOGICAL VIBRATING MACHINE

2018 ◽  
Vol 2018 (7) ◽  
pp. 44-55
Author(s):  
Куанг Выонг ◽  
Kuang Vyong
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Oscillation Amplitude ◽  
Amplitude Distribution ◽  
Simultaneous Action ◽  
Dynamic Effects ◽  
Surface Source ◽  
Two Factors ◽  
Reac Tions ◽  
Characteristic Points

The paper reports the consideration of technolo-gical vibrating machine dynamic properties on the ba-sis of the model as a mechanical oscillating system with two degrees of freedom having in its structure a device for motion conversion (DMC) forming addi-tional inertial couplings at the simultaneous action of two external harmonic factors. The purpose of investi-gations consists in the development of the method for the formation of simulators ensuring possibilities for dynamic states assessments at the use of such parame-ters of a state as a relation of ties dynamic reactions between a supporting surface (source of kinematic dis-turbance) and a work apparatus. For investigations there is used a method of structural mathematical modeling within the limits of which the mechanical oscillating system is compared with a structural circuit equivalent dynamically a sys-tem of automatic control. There is offered a technology of starting simulators transformation ensuring a defini-tion of tie dynamic reactions in characteristic points of element contact connection of the system at the simul-taneous action of two factors. It is shown that the joint action of two external disturbances does not change frequencies of characteristic oscillations in the system, but affects considerably its dynamic properties. There are shown diagrams of the dependences of motion points and values of tie dynamic reactions in characteristic points upon a frequency of external im-pact. The manifestations of new dynamic effects in the interactions of system elements between each other as a formation of additional modes of oscillation dynamic damping and amplitude-frequency characteristics (AFC) of a certain type are shown. Dynamic effects predetermine potentialities of a purposeful tuning of vibration fields. It is shown that the value of the shown DMC mass of affect substantially dynamic properties of the system that can be used both for motion parame-ter control, and for the assessment of tie dynamic reac-tions arising at that in the system.

scholarly journals DIRECTIONS OF IMPROVING THE EFFICIENCY OF VIBRATION TECHNOLOGICAL MACHINES

2020 ◽  
pp. 49-58
Author(s):  
Oleg Omelyanov ◽  
Mykhailo Zamriі
Keyword(s):  
Mathematical Modeling ◽  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
New Technology ◽  
Oscillatory System ◽  
Simultaneous Action ◽  
Oscillatory Systems ◽  
Technical Developments ◽  
Vibration Field ◽  
Working Bodies

The article considers the directions of increasing the efficiency of vibrating technological machines. The processing of information on the development of vibration technologies is quite diverse and is represented by numerous scientific and technical developments related to improving the efficiency of vibration machines and ensuring the reliability of their work. The analytical basis for previous research in the creation of new technology are mathematical models that reflect the properties of mechanical oscillatory systems with several degrees of freedom, which perform small oscillations under the action of a system of periodic external perturbations that create vibration fields of one configuration. The dynamic properties of the working bodies of machines in a detailed form are revealed as the distribution of the amplitudes of oscillations of the points of the working bodies. In many cases, this distribution is linear, which is due to the manifestations of the properties of the simplest movements of the working bodies. Approaches are proposed in which the possible structural mathematical modeling is realized on the idea that a linear mechanical oscillatory system with concentrated parameters and several degrees of freedom can be compared with the structural scheme of the automatic control system. Particular attention is paid to the study and evaluation of the possibility of new dynamic effects associated with the simultaneous action of several working bodies of machines, as well as - modes of dynamic damping of oscillations. An important role in ensuring such developments is played by areas of research focused on the development of methods of mathematical modeling. Based on the research it is shown that the vibration field of the vibrating technological machine is formed under the influence of several factors, which are determined by the simultaneous action of several force perturbations, asymmetry of inertial and elastic properties of the mechanical system, the presence of additional connections. The introduction of additional links in the structure of the mechanical oscillating system of the vibrating machine, can significantly affect the structure of the vibration field, providing the choice of conditions for rational organization of the technological process of vibration processing, such as vibration hardening, crushing, transportation, screening.

scholarly journals Design, Fabrication, and Testing of a Novel 3D 3-Fingered Electrothermal Microgripper with Multiple Degrees of Freedom

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 444
Author(s):  
Guoning Si ◽  
Liangying Sun ◽  
Zhuo Zhang ◽  
Xuping Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Polyimide Film ◽  
Zebrafish Embryos ◽  
Multiple Degrees Of Freedom ◽  
Electrothermal Actuator ◽  
3D Space ◽  
Pick And Place

This paper presents the design, fabrication, and testing of a novel three-dimensional (3D) three-fingered electrothermal microgripper with multiple degrees of freedom (multi DOFs). Each finger of the microgripper is composed of a V-shaped electrothermal actuator providing one DOF, and a 3D U-shaped electrothermal actuator offering two DOFs in the plane perpendicular to the movement of the V-shaped actuator. As a result, each finger possesses 3D mobilities with three DOFs. Each beam of the actuators is heated externally with the polyimide film. The durability of the polyimide film is tested under different voltages. The static and dynamic properties of the finger are also tested. Experiments show that not only can the microgripper pick and place microobjects, such as micro balls and even highly deformable zebrafish embryos, but can also rotate them in 3D space.

scholarly journals Designing of Drive Systems in the Aspect of the Desired Spectrum of Operation

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2562
Author(s):  
Tomasz Dzitkowski ◽  
Andrzej Dymarek ◽  
Jerzy Margielewicz ◽  
Damian Gąska ◽  
Lukasz Orzech ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Dynamic Parameters ◽  
Synthesis Algorithm ◽  
Moments Of Inertia ◽  
Driving System ◽  
Six Degrees Of Freedom ◽  
Resonance Frequencies ◽  
Drive Systems ◽  
Power Component

A method for selecting dynamic parameters and structures of drive systems using the synthesis algorithm is presented. The dynamic parameters of the system with six degrees of freedom, consisting of a power component (motor) and a two-speed gearbox, were determined, based on a formalized methodology. The required gearbox is to work in specific resonance zones, i.e., meet the required dynamic properties such as the required resonance frequencies. In the result of the tests, a series of parameters of the drive system, defining the required dynamic properties such as the resonance and anti-resonance frequencies were recorded. Mass moments of inertia of the wheels and elastic components, contained in the required structure of the driving system, were determined for the selected parameters obtained during the synthesis.

scholarly journals Exact mapping between a laser network loss rate and the classical XY Hamiltonian by laser loss control

Nanophotonics ◽  
2020 ◽  
Vol 9 (13) ◽  
pp. 4117-4126 ◽  
Author(s):  
Igor Gershenzon ◽  
Geva Arwas ◽  
Sagie Gadasi ◽  
Chene Tradonsky ◽  
Asher Friesem ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Loss Rate ◽  
Oscillation Amplitude ◽  
Xy Model ◽  
Spin Hamiltonian ◽  
Laser Oscillator ◽  
Physical Systems ◽  
Network State ◽  
Spin Hamiltonians ◽  
Loss Control

AbstractRecently, there has been growing interest in the utilization of physical systems as heuristic optimizers for classical spin Hamiltonians. A prominent approach employs gain-dissipative optical oscillator networks for this purpose. Unfortunately, these systems inherently suffer from an inexact mapping between the oscillator network loss rate and the spin Hamiltonian due to additional degrees of freedom present in the system such as oscillation amplitude. In this work, we theoretically analyze and experimentally demonstrate a scheme for the alleviation of this difficulty. The scheme involves control over the laser oscillator amplitude through modification of individual laser oscillator loss. We demonstrate this approach in a laser network classical XY model simulator based on a digital degenerate cavity laser. We prove that for each XY model energy minimum there corresponds a unique set of laser loss values that leads to a network state with identical oscillation amplitudes and to phase values that coincide with the XY model minimum. We experimentally demonstrate an eight fold improvement in the deviation from the minimal XY energy by employing our proposed solution scheme.

Dither in a rolling airframe flight vehicle with a two-position actuator: An amplitude distribution approach

2016 ◽  
Vol 39 (8) ◽  
pp. 1205-1215 ◽  
Author(s):  
Bahram Mohammadi ◽  
Mohammad Reza Arvan ◽  
Yousof Koohmaskan
Keyword(s):  
High Frequency ◽  
Degrees Of Freedom ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Amplitude Distribution ◽  
Feedback System ◽  
Flight Vehicle ◽  
Frequency Signal ◽  
High Frequency Signal ◽  
Minimal Error

Rolling airframe manoeuvring is a type of manoeuvre in which the missile provides continuous roll during flight. Cross-coupling between the angle of attack and sideslip in rolling airframe missiles (RAMs) yields a coning motion around the flight path. As the pitch and yaw cross-coupling effect decreases, the radius of this coning motion decreases and the accuracy of the control system increases. Two-position (on–off) actuators are used in most RAMs. The presence of a two-position actuator in a feedback system makes its characteristics non-linear. A high-frequency signal so-called dither is applied to compensate for the non-linearity effect of the actuator characteristic in the feedback system and to stabilize the coning motion. The amplitude distribution function (ADF) method in dither analysis shows that the smoothed non-linearity characteristic can be computed as the convolution of the original non-linearity and the ADF of the dither signal. According to the four-degrees-of-freedom (4-DOF) equations of RAMs in a non-rolling frame and regarding various dither signals through the ADF approach on a two-position actuator, an analytical condition for dither amplitude in coning motion stability of RAMs is derived. It was shown that the triangular signal with specified amplitude and high enough frequency led to a smoother response of two-position actuators. Finally, by applying beam-riding guidance to a RAM, the performance of dithers for decreasing the distance of the missile from the centre of the beam is validated through simulations. It is illustrated that applying the triangular dither resulted in minimal error.

Experimental and Analytical Investigations of a Low Pressure Model Turbine During Forced Response Excitation

2010 ◽  
Author(s):  
Christoph Heinz ◽  
Markus Schatz ◽  
Michael V. Casey ◽  
Heinrich Stu¨er
Keyword(s):  
Degrees Of Freedom ◽  
Timing Analysis ◽  
Dynamic Performance ◽  
Amplitude Distribution ◽  
Low Pressure ◽  
Forced Response ◽  
Operating Conditions ◽  
Linear Regression Method ◽  
Rotor Shaft ◽  
Aerodynamic Damping

To guarantee a faultless operation of a turbine it is necessary to know the dynamic performance of the machine especially during start-up and shut-down. In this paper the vibration behaviour of a low pressure model steam turbine which has been intentionally mistuned is investigated at the resonance point of an eigenfrequency crossing an engine order. Strain gauge measurements as well as tip timing analysis have been used, whereby a very good agreement is found between the methods. To enhance the interpretation of the data measured, an analytical mass-spring-model, which incorporates degrees of freedom for the blades as well as for the rotor shaft, is presented. The vibration amplitude varies strongly from blade to blade. This is caused by the mistuning parameters and the coupling through the rotor shaft. This circumferential blade amplitude distribution is investigated at different operating conditions. The results show an increasing aerodynamic coupling with increasing fluid density, which becomes visible in a changing circumferential blade amplitude distribution. Furthermore the blade amplitudes rise non-linearly with increasing flow velocity, while the amplitude distribution is almost independent. Additionally, the mechanical and aerodynamic damping parameters are calculated by means of a non-linear regression method. Based on measurements at different density conditions, it is possible to extrapolate the damping parameters down to vacuum conditions, where aerodynamic damping is absent. Hence the material damping parameter can be determined.

Modal Simulation and Testing of a Micro-Manipulator

2004 ◽  
Vol 127 (3) ◽  
pp. 515-519 ◽  
Author(s):  
Yongjun Lai ◽  
Marek Kujath ◽  
Ted Hubbard
Keyword(s):  
Numerical Simulations ◽  
Degrees Of Freedom ◽  
Compliant Mechanism ◽  
Dynamic Properties ◽  
Experimental Results ◽  
Mass Model ◽  
Thermal Actuators ◽  
Micro Manipulator ◽  
Six Dof

A micro-machined manipulator with three kinematic degrees-of-freedom (DOF): x, y, and φ is presented. The manipulator is driven by three thermal actuators. A six DOF discrete spring-mass model of the compliant mechanism is developed which manifests the dynamic properties of the device. Numerical simulations are compared with experimental results.

scholarly journals Low-amplitude dynamic tests of fine gravel in a resonant column

2019 ◽  
Vol 97 ◽  
pp. 04024
Author(s):  
Zaven Ter-Martirosyan ◽  
Evgeny Sobolev ◽  
George Anzhelo
Keyword(s):  
Mechanical Properties ◽  
Dynamic Properties ◽  
Sample Volume ◽  
Coarse Grained ◽  
Software Systems ◽  
Resonant Column ◽  
Dynamic Effects ◽  
Laboratory Equipment ◽  
Aggregate Fractions ◽  
Sample Assembly

Construction of industrial and civil buildings, taking into account the dynamic effects on the foundations, requires special experiments on the mechanical properties of soils. This article presents the results of studying the dynamic properties of coarse gravelly soils using the resonant column method. These studies are relevant, since the determination of the dynamic properties of coarse-grained soils under laboratory conditions is associated with a restriction on the size of the fractions in the sample volume. This circumstance leads to the fact that at the moment most of the laboratory tests of the dynamic properties of coarse-grained soils are performed on smaller aggregate fractions, which, in general, significantly reduces the resulting mechanical properties of soils. It does not reflect the real operation of the foundation of buildings during dynamic effects. This paper presents a description of the available laboratory equipment, the sequence of preparation of samples of coarse grained crushed stone soil and sample assembly in the working chamber of the installation. The article contains the main graphs characterizing the change in shear modulus and damping coefficient depending on shear deformations. It is noted that the results obtained are particularly relevant for modeling the dynamic effects of natural and man-made character on the foundations of industrial and civil buildings, the bases of which are composed of coarse-grained soils. Dynamic parameters considered in this paper, can and must be used in numerical calculations by finite element method with the use of modern groundwater models in geotechnical software systems.

Methodological and Technical Aspects of a Two-Degrees-of-Freedom Hardware-In-the-Loop Setup for Wind Tunnel Tests of Floating Systems

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Simone Ambrosini ◽  
Ilmas Bayati ◽  
Alan Facchinetti ◽  
Marco Belloli
Keyword(s):  
Wind Tunnel ◽  
Degrees Of Freedom ◽  
Scale Model ◽  
Simultaneous Action ◽  
Offshore Wind Turbine ◽  
Hardware In The Loop ◽  
Technical Aspects ◽  
Two Degrees Of Freedom ◽  
Floating System ◽  
Floating Systems

Abstract This paper presents the methodological and technical aspects of the implementation of a hardware-in-the-loop experimental setup, suitable to simulate the dynamics of a floating system in wind tunnel experiments. The presented work is based on the specific application of a floating offshore wind turbine scale model, even if the approach holds also for floating systems in general, being subjected to the simultaneous action of wind and waves. The setup is based on a two degrees-of-freedom system, providing the motion of the floating system along surge and pitch. With reference to the implementation of the HIL test methodology the following topics are thoroughly analyzed: scaling issues, numerical issues, mechanical system characterization, force corrections, measurement, and signal processing. For each of these topics the methodological approach is presented, and the technical issues are described. A subset of results is then reported to show the effectiveness of such experimental apparatus, for different sea states: still water, regular, and irregular waves.

Analysis of Varying Natural Frequencies and Damping Ratios of a Sample Parallel Manipulator Throughout its Workspace Using Linearized Equations of Motion

2001 ◽  
Author(s):  
Kris Kozak ◽  
Imme Ebert-Uphoff ◽  
William Singhose
Keyword(s):  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Equations Of Motion ◽  
Parallel Architecture ◽  
Robotic Manipulators ◽  
Parallel Manipulators ◽  
Dynamic Equations ◽  
Extreme Variation

Abstract This article investigates the dynamic properties of robotic manipulators of parallel architecture. In particular, the dependency of the dynamic equations on the manipulator’s configuration within the workspace is analyzed. The proposed approach is to linearize the dynamic equations locally throughout the workspace and to plot the corresponding natural frequencies and damping ratios. While the results are only applicable for small velocities of the manipulator, they present a first step towards the classification of the nonlinear dynamics of parallel manipulators. The method is applied to a sample manipulator with two degrees-of-freedom. The corresponding numerical results demonstrate the extreme variation of its natural frequencies and damping ratios throughout the workspace.

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