scholarly journals Compensation Gyrocompass Based on MEMS

2021 ◽  
Vol 2096 (1) ◽  
pp. 012203
Author(s):  
V Bogolyubov ◽  
L Bakhtieva
Keyword(s):  
Mathematical Model ◽  
Coordinate System ◽  
Longitudinal Axis ◽  
Main Axis ◽  
Effective Algorithm ◽  
Good Resistance ◽  
Micromechanical Gyroscope ◽  
Ground Object ◽  
Zero Offset ◽  
Kinematic Diagram

Abstract The study of an astatic compensating gyrocompass, built on the basis of a modulation micromechanical gyroscope (MMG) of a hybrid type, has been carried out. A kinematic diagram is given and the principle of operation of the device has describing. The device uses the modulation principle based on obtaining information about the angular motion of the rotor and creating control torques in a rotating coordinate system, which makes it possible to exclude such a significant disadvantage of MMG as "zero offset". A feature of the gyrocompass under consideration is the use of two channels for controlling the rotor of the MMG, namely: a channel for the formation of a guiding moment, striving to combine its main axis with the direction of the true meridian and a channel for compensating this guiding moment. A linearized mathematical model has building, on the base of which an effective algorithm for the operation of a compensatory astatic gyrocompass is proposed. The device under consideration can be used to determine the true azimuth of the longitudinal axis of a mobile ground object, it has a higher measurement speed compared to devices built on three-degree "heavy" gyroscopes, and has good resistance to external influences (vibrations, shocks, etc.).

Determination of non!contact deformation of a material under the orbital action of an indenter

2021 ◽  
pp. 81-86
Author(s):  
Keyword(s):  
Mathematical Model ◽  
Elastoplastic Deformation ◽  
Contact Deformation ◽  
Elastoplastic Wave ◽  
Kinematic Diagram ◽  
Wave Size

The influence of kinematic loading schemes on the formation of an elastoplastic wave under the orbital action of an indenter is considered. A mathematical model of hardening is presented, which determines the size and stressstrain state of the wave. The loading parameters influencing the wave size are determined. Keywords: kinematic diagram, orbital loading, deforming element, elastoplastic deformation, non-contact deformation, elastoplastic wave [email protected]

Preparation of On-Axis Cylindrical Trabecular Bone Specimens Using Micro-CT Imaging

2004 ◽  
Vol 126 (1) ◽  
pp. 122-125 ◽  
Author(s):  
Xiang Wang, ◽  
Xiangyi Liu, and ◽  
Glen L. Niebur
Keyword(s):  
Finite Element ◽  
High Resolution ◽  
Coordinate System ◽  
Trabecular Bone ◽  
Cylindrical Specimen ◽  
Longitudinal Axis ◽  
Ct Imaging ◽  
Finite Element Models ◽  
Micro Ct ◽  
Average Deviation

The Orientation of trabecular bone specimens for mechanical testing must be carefully controlled. A method for accurately preparing on-axis cylindrical specimens using high-resolution micro-CT imaging was developed. Sixteen cylindrical specimens were prepared from eight bovine tibiae. High-resolution finite element models were generated from micro-CT images of parallelepipeds and used to determine the principal material coordinate system of each parallelepiped. A cylindrical specimen was then machined with a diamond coring bit. The resulting specimens were scanned again to evaluate the orientation. The average deviation between the principal fabric orientation and the longitudinal axis of the cylindrical specimen was only 4.70±3.11°.

A Musculoskeletal Model of the Equine Forelimb for Determining Surface Stresses and Strains in the Humerus—Part II. Experimental Testing and Model Validation

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Sarah Pollock ◽  
Susan M. Stover ◽  
M. L. Hull ◽  
Larry D. Galuppo
Keyword(s):  
Mathematical Model ◽  
Stress Fracture ◽  
Biceps Brachii ◽  
Experimental Testing ◽  
Longitudinal Axis ◽  
Principal Strain ◽  
Longitudinal Strains ◽  
The Mathematical Model ◽  
Experimental Strains

The first objective of this study was to experimentally determine surface bone strain magnitudes and directions at the donor site for bone grafts, the site predisposed to stress fracture, the medial and cranial aspects of the transverse cross section corresponding to the stress fracture site, and the middle of the diaphysis of the humerus of a simplified in vitro laboratory preparation. The second objective was to determine whether computing strains solely in the direction of the longitudinal axis of the humerus in the mathematical model was inherently limited by comparing the strains measured along the longitudinal axis of the bone to the principal strain magnitudes and directions. The final objective was to determine whether the mathematical model formulated in Part I [Pollock et al., 2008, ASME J. Biomech. Eng., 130, p. 041006] is valid for determining the bone surface strains at the various locations on the humerus where experimentally measured longitudinal strains are comparable to principal strains. Triple rosette strain gauges were applied at four locations circumferentially on each of two cross sections of interest using a simplified in vitro laboratory preparation. The muscles included the biceps brachii muscle in addition to loaded shoulder muscles that were predicted active by the mathematical model. Strains from the middle grid of each rosette, aligned along the longitudinal axis of the humerus, were compared with calculated principal strain magnitudes and directions. The results indicated that calculating strains solely in the direction of the longitudinal axis is appropriate at six of eight locations. At the cranial and medial aspects of the middle of the diaphysis, the average minimum principal strain was not comparable to the average experimental longitudinal strain. Further analysis at the remaining six locations indicated that the mathematical model formulated in Part I predicts strains within ±2 standard deviations of experimental strains at four of these locations and predicts negligible strains at the remaining two locations, which is consistent with experimental strains. Experimentally determined longitudinal strains at the middle of the diaphysis of the humerus indicate that tensile strains occur at the cranial aspect and compressive strains occur at the caudal aspect while the horse is standing, which is useful for fracture fixation.

Numerical Modelling of Shape Evolution of Tubular Preform in Spray Forming Process

2011 ◽  
Vol 189-193 ◽  
pp. 2426-2433 ◽  
Author(s):  
Jin Zong Xiang ◽  
Yin Zhang ◽  
Wen Jun Fan ◽  
You Duo He
Keyword(s):  
Mathematical Model ◽  
Numerical Modelling ◽  
Three Dimensional ◽  
Spray Forming ◽  
Geometrical Shape ◽  
Shape Evolution ◽  
Effective Algorithm ◽  
Forming Process ◽  
Movement Parameters

A three-dimensional mathematical model of growth, integrated with a new and effective algorithm for visibility checking, has been established based on a spray forming equipment with three different fixed atomizers in this paper. The model was used to predict the geometrical shape and the thickness profiles of the tubular deposit under various situations. By investigating and discussing the effects of different mandrel movement parameters and spray heights, the optimal atomizer of the equipment to fabricate a tubular preform was identified numerically.

scholarly journals Laboratory Stand for Simplified Verification of Missile Dynamics for Didactic Purposes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Adam Rowicki ◽  
Grzegorz Kopecki
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Coordinate System ◽  
Second Law ◽  
Matlab Simulink ◽  
Pi Regulator ◽  
System Parameters ◽  
Proportional Integral ◽  
Roll System ◽  
Newton's Second Law

Abstract The purpose of this study was to describe dynamics of missile based on bibliography, simplify the model to the easiest form, and verify it with the use of a designed laboratory stand. Next, a simple control system of the missile was designed. The stand is prepared for didactic purposes. A mathematical model was derived by applying Newton's second law together with the earth's coordinate system and the base coordinate system. Parameters of the actual rocket model were determined using the created laboratory stand. Synthesis of the rocket roll system was designed using Simulink PID Tuner application (MathWorks, Inc. Natick, Massachusetts, USA). A control system was based on a proportional-integral (PI) regulator. The designed control system was subjected to simulated tests in MATLAB Simulink (MathWorks, Inc. Natick, Massachusetts, USA).

scholarly journals PREFERENCES OF USING GEOINFORMATION SYSTEMS FOR FIXATION ON ARCHAEOLOGICAL OBJECTS

2019 ◽  
Vol 30 (1) ◽  
pp. 218-230 ◽  
Author(s):  
O. V. Manihda ◽  
V. A. Hnera
Keyword(s):  
Coordinate System ◽  
Urban Space ◽  
Effective Algorithm ◽  
Geoinformation System ◽  
Geoinformation Systems ◽  
Gis Model ◽  
Archaeological Object ◽  
Different Types ◽  
Types Of Information ◽  
Archaeological Objects

The paper proposes examples of archaeological objects fixing using Geoinformation system (GIS) as an effective computer-supported system used for a digital visualization and analysis of geographic features and events happening on them. The main preference of using these methods is disclosed due to elaborations of specialists worked in Architectural-archaeological expedition of Archaeology Institute of NASU for several years. There is an experience gained in field and urban space. According to this thesis main preferences that is noticed by authors are: 1) an accuracy of fixing in a difficult conditions; 2) multipurpose and flexibility of coordinate system; 3) a unique format of different file types; 4) an opportunity of object reconstruction based on earlier drawing; 5) creation a topography ground (basic plan) for future excavations; 6) combining in one GIS model different types of information that is appropriate to an archaeological object; 7) join the attribute tables of database related to archaeological objects fixed during the excavation in GIS formats. An effective algorithm of object fixing is proposed by using the most basic methods of GIS.

scholarly journals Determination of intersecting curve between two surfaces of revolution with parallel axes by use of auxiliary planes and auxiliary spheres

2002 ◽  
Vol 2 (4) ◽  
pp. 267-272
Author(s):  
Ratko Obradovic
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Coordinate System ◽  
Surfaces Of Revolution ◽  
Surface Of Revolution ◽  
First Case ◽  
Intersecting Curve

In this paper the space intersecting curve between two surfaces of revolution with parallel axes of surfaces have been determined. Two mathematical models for determination of intersecting curve between two surfaces of revolution have been formed: auxiliary planes have been used in the first mathematical model and auxiliary spheres have been used in the second model (Obradovic 2000). In the first case each auxiliary plane intersected with each surface of revolution on circle and two points of intersecting curve are obtained as intersecting points between these two circles. In the second case centres of two locks of auxiliary spheres are put on axes of surfaces of revolution (centre of first lock is on axis of the first surface of revolution and centre of second lock is on axis of the second surface of revolution) on saine z coordinate (when axes of surfaces of revolution are parallel with z axis of coordinate system). First lock sphere intersects the first surface of revolution on w1 parallels and second lock corresponding sphere intersects the second surface of revolution on w2 circles. It is possible to find a relationship that for selected radius of the first lock sphere can determine the radius of second lock sphere and real points of intersecting curve have been determined by use of these two spheres. The points of intersecting curve between two surfaces of revolution are obtained by intersection between w1 circles from the first surface with w2 circles from the second surface (Obradovic 2000).

Vulnerability of different nerves to intrafascicular injection by different needle types and at different approach angles: a mathematical model

2020 ◽  
Vol 45 (4) ◽  
pp. 306-310
Author(s):  
Margarita Sanromán-Junquera ◽  
Andre Boezaart ◽  
Yury Zasimovich ◽  
Olga C Nin ◽  
Xavier Sala-Blanch ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Cross Sections ◽  
Longitudinal Axis ◽  
Needle Insertion ◽  
Nerve Roots ◽  
Nerve Blocks ◽  
Cross Sectional ◽  
Peripheral Nerve Blocks ◽  
Microscopic Images ◽  
Insertion Angle

Background and objectivesWe assume that intrafascicular spread of a solution can only occur if a large enough portion of the distal needle orifice is placed inside the fascicle. Our aim is to present and evaluate a mathematical model that can calculate the theoretical vulnerability of fascicles, analyzing the degree of occupancy of the needle orifice in fascicular tissue by performing simulations of multiple positions that a needle orifice can take inside a cross-sectional nerve area.MethodsWe superimposed microscopic images of two routinely used nerve block needles (22-gauge, 15° needle and 22-gauge, 30° needle) over the microscopic images of cross-sections of four nerve types photographed at the same magnification. Fascicular tissue that was overlapped between 80% and 100% by a needle orifice was considered at risk to possible intrafascicular injection. The effect of three angular approaches was evaluated.ResultsThere were statistical differences between the vulnerability of fascicular tissue depending on nerve type, the bevel angle of the needle and the angle approach. Fascicular vulnerability was greater in nerve roots of the brachial plexus after using a 22-gauge 30° needle, as was choosing a 45° angle approach to the longitudinal axis of the nerve.ConclusionsOur results suggest that clinicians may want to consider needle insertion angle and bevel type as they perform peripheral nerve blocks. Furthermore, researchers may want to consider this mathematical model when estimating vulnerabilities of various nerves, needle types and angles of approach of needles to nerves.

Modeling and Calibration of Grid Structured Light Based 3-D Vision Inspection

1999 ◽  
Vol 122 (4) ◽  
pp. 734-738 ◽  
Author(s):  
Guangjun Zhang ◽  
Liqun Ma
Keyword(s):  
Mathematical Model ◽  
Coordinate System ◽  
Structured Light ◽  
Calibration Method ◽  
Experimental Results ◽  
Image Feature ◽  
Feature Analysis ◽  
Calibration Process ◽  
Vision Inspection ◽  
The Mathematical Model

The principle of structured light 3-D vision is introduced, and using projective and perspective transformations, the mathematical model of grid structured light based 3-D vision inspection is established in homogeneous coordinate system in this paper. Based on the image feature analysis of grid structured light, a calibration method of grid structured light based 3-D vision inspection is proposed, and experimental results are also presented. This method is easy, efficient and fast to carry out. It simplifies the calibration process while guaranteeing its accuracy. [S1087-1357(00)00703-6]

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