Dynamics of a Ring-Type Macro Gyroscope Under Electromagnetic External Actuation Forces

2018 ◽  
Author(s):  
Ibrahim F. Gebrel ◽  
Ligang Wang ◽  
Samuel F. Asokanthan
Keyword(s):  
Electromagnetic Force ◽  
Dynamic Behaviour ◽  
Essential Element ◽  
Ring Structure ◽  
Ring System ◽  
Response Behavior ◽  
External Excitation ◽  
Actuator Dynamics ◽  
Vibratory Gyroscopes ◽  
Galerkin's Procedure

This paper investigates the dynamic behaviour of a rotating ring that forms an essential element in ring-based vibratory gyroscopes that utilize oscillatory electromagnetic forces. Understanding the effects of nonlinear actuator dynamics is considered important for characterizing the dynamic behavior of such devices. A suitable theoretical model to generate nonlinear electromagnetic force that acts on the ring structure is formulated. In order to predict the dynamic behaviour of a ring system subjected to external excitation and body rotation, discretized equations obtained via Galerkin’s procedure is employed to investigate the time as well as frequency response behavior. Dynamic response in the driving and the sensing directions are examined via time responses, phase diagram, Poincare’ map and bifurcation plots when the input angular motion and the nonlinear electromagnetic force are considered simultaneously. The analysis is envisaged to aid ongoing experimental research as well as for providing design improvements in Ring-based Gyroscopes.

Dynamics of MEMS-Based Angular Rate Sensors Excited via External Electrostatic Forces

2020 ◽  
Author(s):  
Ibrahim F. Gebrel ◽  
Ligang Wang ◽  
Samuel F. Asokanthan
Keyword(s):  
Dynamic Behavior ◽  
Electrostatic Force ◽  
Angular Rate ◽  
Equations Of Motion ◽  
Ring Structure ◽  
Dynamic Responses ◽  
Actuator Dynamics ◽  
Vibratory Gyroscopes ◽  
Thin Ring ◽  
The Mathematical Model

Abstract This paper investigates the dynamic behavior of rotating MEMS-based vibratory gyroscopes which employs a thin ring as the vibrating flexible element. The mathematical model for the MEMS ring structure as well as a model for the nonlinear electrostatic excitation forces are formulated. Galerkin’s procedure is employed to reduce the equations of motion to a set of ordinary differential equations. Understanding the effects of nonlinear actuator dynamics is considered important for characterizing the dynamic behavior of such devices. A suitable theoretical model to generate nonlinear electrostatic force that acts on the MEMS ring structure is formulated. Dynamic responses in the driving and the sensing directions are examined via time responses, phase diagram, and Poincare’ map plots when the input angular motion and the nonlinear electrostatic force are considered simultaneously. The analysis is envisaged to aid fabrication of this class of devices as well as for providing design improvements in MEMS Ring-based Gyroscopes.

scholarly journals Influence of System and Actuator Nonlinearities on the Dynamics of Ring-Type MEMS Gyroscopes

Vibration ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 805-821
Author(s):  
Ibrahim F. Gebrel ◽  
Samuel F. Asokanthan
Keyword(s):  
Differential Equations ◽  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
Electrostatic Force ◽  
Essential Element ◽  
Ring Structure ◽  
Dynamic Responses ◽  
Ongoing Research ◽  
Actuator Dynamics ◽  
External Forces

This study investigates the nonlinear dynamic response behavior of a rotating ring that forms an essential element of MEMS (Micro Electro Mechanical Systems) ring-based vibratory gyroscopes that utilize oscillatory nonlinear electrostatic forces. For this purpose, the dynamic behavior due to nonlinear system characteristics and nonlinear external forces was studied in detail. The partial differential equations that represent the ring dynamics are reduced to coupled nonlinear ordinary differential equations by suitable addition of nonlinear mode functions and application of Galerkin’s procedure. Understanding the effects of nonlinear actuator dynamics is essential for characterizing the dynamic behavior of such devices. For this purpose, a suitable theoretical model to generate a nonlinear electrostatic force acting on the MEMS ring structure is formulated. Nonlinear dynamic responses in the driving and sensing directions are examined via time response, phase diagram, and Poincare’s map when the input angular motion and nonlinear electrostatic force are considered simultaneously. The analysis is envisaged to aid ongoing research associated with the fabrication of this type of device and provide design improvements in MEMS ring-based gyroscopes.

The Dynamic Behaviour of Passively Compensated, Hydrostatic Journal Bearings with Various Numbers of Recesses

1976 ◽  
Vol 18 (6) ◽  
pp. 292-302 ◽  
Author(s):  
P. B. Davies
Keyword(s):  
Dynamic Behaviour ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Steady State Solution ◽  
Flow Equation ◽  
External Excitation ◽  
Signal Flow Graphs ◽  
Flow Compensation ◽  
Circular Functions ◽  
Flow Graphs

A previously established small-perturbation analysis is developed to express the unsteady-state continuity-of-flow equation for an isolated recess in a passively compensated, multirecess, hydrostatic journal bearing in terms of generalized co-ordinates. The concise form of this equation enables motion of the shaft about the concentric position to be described by equations which are derived in closed form for bearings with orifice, capillary or constant flow compensation and any number of recesses. These equations of motion, and hence the expressions for the receptances which describe the response of a bearing to external excitation, are shown to be of exactly the same form for all bearings of the type considered. Furthermore, the damping ratio and natural frequency in any particular case are determined by a single dynamic constant which is shown to be equal to a linear combination of circular functions and a limited number of coefficients which may be found explicitly by routine use of signal flow graphs. The results of the analysis, which is exact within the stated assumptions, are compared with those of other workers and the steady-state solution of the equations of motion is shown to give an expression for static stiffness which is useful for design purposes. Numerical values of the dynamic constant for bearings with between 3 and 20 recesses are given graphically.

On the Dynamic Behaviour of Offshore Foundation Footings in a Moving Ocean Bed

2006 ◽  
Author(s):  
Vincent O. S. Olunloyo ◽  
Charles A. Osheku
Keyword(s):  
Dynamic Behaviour ◽  
Integral Transform ◽  
Three Dimensional ◽  
Dynamic Interaction ◽  
External Excitation ◽  
Foundation Soil ◽  
Hydrodynamic Loading ◽  
Response Profiles ◽  
And Performance ◽  
Soil Dynamic

The reliability of partly submerged production storage platforms deployed for the exploitation of geo-resources in deep and ultra-deep offshore locations is strongly influenced by the dynamic stability and performance of their foundation footings under hydrodynamic loading and external excitation. This paper presents an integral transform approach for investigating the effects of the three-dimensional motion of the gripping ocean bed subsoil layer under pressurized external excitation. For this, the fluid-foundation-soil dynamic interaction boundary value problem is modeled as an elastic plate on an elastic foundation. In particular, closed form expressions for the dynamic response profiles and the natural frequency of vibration as modulated by the ocean bed poro-mechanics are analysed and presented.

Das dynamische Verhalten des 1-Methyl-1-benzothiepinium-Ringsystems/The Dynamic Behaviour of the 1-Methyl-1-benzothiepinium Ring System

1981 ◽  
Vol 36 (8) ◽  
pp. 974-977 ◽  
Author(s):  
Hans Hofmann ◽  
Franz Dickert
Keyword(s):  
Nmr Spectroscopy ◽  
Room Temperature ◽  
Dynamic Behaviour ◽  
Ring System ◽  
Membered Ring ◽  
Ring Inversion ◽  
Methyl Group ◽  
H Nmr ◽  
Pyramidal Inversion ◽  
Mutual Conversion

Abstract By 1H NMR spectroscopy the stereochemistry of the 1-methyl-1-benzothiepinium ring system was investigated both in thermodynamic and kinetic respects. It was shown that in solution a rapid mutual conversion of the boat shaped seven membered ring system with exo-respectively endo-S-methyl group occurs via a ring inversion and not by a pyramidal inversion at the sulfonium ion. At room temperature predominantly the conformation with the exo-S-methyl group is present.

scholarly journals ALMA and NACO observations towards the young exoring transit system J1407 (V1400 Cen)

2020 ◽  
Vol 633 ◽  
pp. A115 ◽  
Author(s):  
M. A. Kenworthy ◽  
P. D. Klaassen ◽  
M. Min ◽  
N. van der Marel ◽  
A. J. Bohn ◽  
...  
Keyword(s):  
Point Source ◽  
Thermal Emission ◽  
Angular Separation ◽  
Ring Structure ◽  
Ring System ◽  
Point Sources ◽  
Transit System ◽  
Orbital Parameters ◽  
Upper Limit ◽  
Infrared Wavelengths

Aims. Our aim was to directly detect the thermal emission of the putative exoring system responsible for the complex deep transits observed in the light curve for the young Sco-Cen star 1SWASP J140747.93-394542.6 (V1400 Cen, hereafter J1407), confirming it as the occulter seen in May 2007, and to determine its orbital parameters with respect to the star. Methods. We used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the field centred on J1407 in the 340 GHz (Band 7) continuum in order to determine the flux and astrometric location of the ring system relative to the star. We used the VLT/NACO camera to observe the J1407 system in March 2019 and to search for the central planetary mass object at thermal infrared wavelengths. Results. We detect no point source at the expected location of J1407, and derive an upper limit 3σ level of 57.6 μJy. There is a point source detected at an angular separation consistent with the expected location for a free-floating ring system that occulted J1407 in May 2007, with a flux of 89 μJy consistent with optically thin dust surrounding a massive substellar companion. At 3.8 μm with the NACO camera, we detect the star J1407 but no other additional point sources within 1.3 arcsec of the star, with a lower bound on the sensitivity of 6 MJup at the location of the ALMA source, and down to 4 MJup in the sky background limit. Conclusions. The ALMA upper limit at the location of J1407 implies that a hypothesised bound ring system is composed of dust smaller than 1 mm in size, implying a young ring structure. The detected ALMA source has multiple interpretations, including: (i) it is an unbound substellar object surrounded by warm dust in Sco-Cen with an upper mass limit of 6 MJup, or (ii) it is a background galaxy.

Dynamic Analysis of Core Magnetic Circuit of Direct Action Solenoid Valve

2010 ◽  
Author(s):  
Qianfeng Liu ◽  
Hanliang Bo ◽  
Benke Qin
Keyword(s):  
Electromagnetic Force ◽  
Magnetic Force ◽  
Magnetic Circuit ◽  
Direct Action ◽  
Hydraulic Drive ◽  
Ring Structure ◽  
Solenoid Valve ◽  
Seal Ring ◽  
Control Rod ◽  
The One

Control rod hydraulic drive mechanism (CRHDM) is a newly invented patent with Institute of Nuclear and New Energy Technology Tsinghua University which owns CRHDM’s independent intellectual property rights. The combined valve which is made up of three direct action solenoid valves is the key part of this technology, so the performance of the solenoid valve directly affects the function of the integrated valve and the CRHDM. The core magnetic circuit of 8 types of the direct action solenoid valve is analyzed using the ANSYS software with various voltages, the results of which are validated by experiments. It shows that the magnetic force increases and time shortens with the increasing voltage. What’s more, under the same condition, the electromagnetic force of the solenoid valve with cone armatures increases much faster than the one of flat armatures, however, the electromagnetic force of the latter is bigger than the former when the force is steady. Furthermore, different shaped interfaces of the seal ring structure between armatures lead to different results. Especially, the electromagnetic force of the solenoid valve with the flat armatures which has seal ring increases faster than the one which does not have this structure, but the result is opposite when it is the solenoid valve with the cone armatures. At last, the subsection structure of magnetic material accelerates the magnetic force sharply.

scholarly journals Sterol Chemical Structure and Conformation Influence the Thermotropic Phase Behaviour of Dipalmitoylphosphatidylcholine Bilayers

Eureka ◽  
2011 ◽  
Vol 2 (1) ◽  
pp. 11-23
Author(s):  
Matthew G.K. Benesch ◽  
David A. Mannock ◽  
Ronald N. McElhaney
Keyword(s):  
Differential Scanning Calorimetry ◽  
Double Bond ◽  
Chemical Structure ◽  
Ring Structure ◽  
Ring System ◽  
Phase Behaviour ◽  
Biological Molecules ◽  
Scanning Calorimetry ◽  
Bilayer Stability

Studying the nature of interactions between the sterol ring system and neigbouring phospholipid molecules is important for our understanding of the properties of sterols in biological molecules and the role of such interactions in many disease processes. In this project, the thermotropic phase behaviour of binary dipalmitoylphosphatidylcholine (DPPC)/sterol mixtures with different sterol ring configurations (C5,6 double bond, 5α-H and 5β-H orientation and either 3α-OH, 3β-OH, 3-ketone functional groups) was investigated using differential scanning calorimetry (DSC) and was compared to earlier studies of cholesterol/ and epicholesterol/DPPC mixtures. Given the differences in the thermodynamic parameters obtained from these mixtures and their associated changes in bilayer stability and miscibility, it is clear that changing the sterol chemical configuration has a significant effect on bilayer properties. Any sterol molecule whose ring structure deviates from that of cholesterol is unlikely to be fully miscible in mammalian membranes.

Structure and dynamical processes in Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 393-395
Author(s):  
Richard J. Terrile
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Large Scale Structure ◽  
Ring Structure ◽  
Ring System ◽  
Scale Structure ◽  
Dynamical Processes ◽  
Saturn’S Rings ◽  
Saturn's Rings

The Voyager encounters have provided the first high resolution look at the Saturn ring system. Images of the rings reveal several classes of dynamical processes active in creating and maintaining large scale structure. These classes include variable ring features attributable to the influence of external satellite resonances, ring structure induced by the shepherding effects from external and possibly internal satellites, smooth eccentric ringlets contained within clear gaps in the ring and the dynamics of spokes which may represent a transient ring atmosphere.

Synthesis and Nonlinearity of Triene Chromophores Containing the Cyclohexene Ring Structure

1997 ◽  
Vol 488 ◽  
Author(s):  
Susan Ermer ◽  
Steven M. Lovejoy ◽  
Doris S. Leung ◽  
Hope Warren ◽  
Christopher R. Moylan ◽  
...  
Keyword(s):  
Dipole Moments ◽  
Heterocyclic Ring ◽  
Ring Structure ◽  
Ring System ◽  
Donor Group ◽  
Active Components ◽  
Cyclohexene Ring ◽  
Electro Optic ◽  
Donor Acceptor ◽  
Conjugated Polyenes

AbstractA series of conjugated donor-acceptor trienes in which the central double bond is incorporated into an unsaturated isophorone, verbenone or chromone ring has been synthesized. In each case, the donor group consists of an amine and an aromatic or heterocyclic ring system, and the acceptor is the dicyanomethylidene group. The nonlinear optical properties of each of the compounds has been measured and correlated with its structure. The dipole moments and molecular hyperpolarizabilities of these compounds, like those of other conjugated polyenes, are large enough to be used as the active components of electro-optic polymers. Unlike other donor-acceptor polyenes, however, these compounds exhibit the thermal stability required for such applications.

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