System of metrological assurance of traceability of measurements of mass geometry characteristics

2020 ◽  
pp. 28-34
Author(s):  
O. V. Dovydenko ◽  
A. I. Samoylenko ◽  
V. V. Petronevich
Keyword(s):  
Center Of Mass ◽  
Mass Center ◽  
Moments Of Inertia ◽  
Technical Requirements ◽  
Type Approval ◽  
Direct Measurements ◽  
Verification Methods ◽  
Reference Measure ◽  
Primary Standards ◽  
The Mathematical Model

A system of metrological support is proposed that allows testing for type approval, verification and calibration of stands for measuring mass, coordinates of mass center and moments of inertia. The mathematical model of a special standard has been developed. It is based on the analytical principles for the determination of the mass center coordinates and inertia moments of homogeneous bodies with a regular geometric shape. The standard consists of a set of modules and fasteners of a special shape. Each module is a reference measure of both mass, center of mass coordinates, and moments of inertia, and can be used either separately or in a set with other modules. A scheme for transferring units of values from state primary standards of mass and length to stands using special standards has been developed. A method for calibration of special standards has been developed. It includes indirect measurements of the coordinates of the center of mass and moments of inertia based on the results of direct measurements of the mass and geometric dimensions of the standard modules’ elements, as well as measurements of the form deviations and deviations of position of the standard modules’ surfaces and static balancing of the standard. Technical requirements for special standards have been developed to minimize methodological measurement uncertainties when reproducing units of values by the standard. A line of special standards was created, their certification and approval in Rosstandart was carried out. Stand verification methods using special standards have been developed and approved. The type approval of two stands was carried out using special standards. The decision to grant a patent for the invention “Method for determining the error of the stand for measuring the characteristics of the mass geometry of products and a device for its implementation” was received.

Detection of Vehicle Tripped and Untripped Rollovers by a Novel Index With Mass-Center-Position Estimations

2017 ◽  
Author(s):  
Fengchen Wang ◽  
Yan Chen
Keyword(s):  
Load Transfer ◽  
Center Of Mass ◽  
Roll Motion ◽  
Mass Center ◽  
Motion Models ◽  
Center Position ◽  
Before And After ◽  
Vehicle Rollover ◽  
Lift Off ◽  
Rollover Index

This paper presents a novel mass-center-position (MCP) metric for vehicle rollover propensity detection. MCP is first determined by estimating the positions of the center of mass of one sprung mass and two unsprung masses with two switchable roll motion models, before and after tire lift-off. The roll motion information without saturation can then be provided through MCP continuously. Moreover, to detect completed rollover statues for both tripped and untripped rollovers, the criteria are derived from d’Alembert principle and moment balance conditions based on MCP. In addition to tire lift-off, three new rollover statues, rollover threshold, rollover occurrence, and vehicle jumping into air can be all identified by the proposed criteria. Compared with an existing rollover index, lateral load transfer ratio, the fishhook maneuver simulation results in CarSim® for an E-class SUV show that MCP metric can successfully predict the vehicle impending rollover without saturation for untripped rollovers. Tripped rollovers caused by a triangle road bump are also successfully detected in the simulation. Thus, MCP metric can be successfully applied for rollover propensity prediction.

scholarly journals SYNTHESIS OF PROGRAM AND FINITE LAWS OF MOTION IN ANALYTICAL MODELS OF CONTROL OF THE FINAL STATE OF BIOMECHANICAL SYSTEMS

2019 ◽  
Vol 19 (1) ◽  
pp. 93-99
Author(s):  
V Zagrevskiy ◽  
O Zagrevskiy
Keyword(s):  
Mathematical Model ◽  
Computer Program ◽  
Center Of Mass ◽  
Material Point ◽  
Object Motion ◽  
Reference Points ◽  
Analytical Models ◽  
Final State ◽  
Finite Control ◽  
The Mathematical Model

Aim. The article deals with developing a computer program to simulate the movement of the object with a given initial and final speed and fixed travel time. Materials and methods. The analysis, as a method of biomechanics, allows us to assess the biomechanical state of the athlete in real sports exercises. The function of motion synthesis is the ability to predict the trajectory and behavior of the biomechanical system at specified reference points of the phase structure of the simulated motion. The article deals with one of the methods of biomechanical synthesis of movements: synthesis of control of the final state of biomechanical systems, based on the reduction of finite control to a given program control after attenuation of the transient component of acceleration. The mathematical description of the object motion is based on the known law of finite control with feedback. Integration of the mathematical model constructed in the form of the differential equation of the second order was carried out by one of the numerical methods of integration: Runge–Kutta method of the fourth order of accuracy. Consideration of the method is based on a mathematical apparatus describing the motion of a material point, which can be represented by a common center of mass of a biomechanical system, a joint, a center of mass of a segment, etc. Results. The mathematical model of the motion of a material point with the given kinematic parameters of motion at the initial and final moments is implemented in a computer program in the Visual Basic 2010 language environment based on the integrated development environment Visual Studio Express 2013. The output provides numerical and visual support for simulation results. Conclusion. It is shown that the developed computer model of the method always implements the goal of motion: to transfer an object from a given initial state by speed to a given final state for a fixed time of movement.

scholarly journals MODELING OF THE SPINE COMPENSATORY RESPONSE TO DEFORMITY

2018 ◽  
Vol 15 (3) ◽  
pp. 85-91
Author(s):  
A. V. Krutko ◽  
A. V. Gladkov ◽  
V. V. Komissarov ◽  
N. V. Komissarova
Keyword(s):  
Mathematical Model ◽  
Center Of Mass ◽  
Kinematic Model ◽  
Sagittal Imbalance ◽  
Spine Deformity ◽  
Compensatory Mechanism ◽  
Spinal Deformities ◽  
Compensatory Response ◽  
The Mathematical Model ◽  
Pathological Situation

Objective. To analyze mathematical model of the efficiency of the compensatory mechanism of the deformed spine. Material and Methods. The developed basic kinematic model of the spine was used. The restoration of the position of the projection of the general center of mass (GCM) was mathematically modeled, and mechanogenesis of the spinal deformity and possibility of its compensation were evaluated. To assess the reliability of the mathematical model, spinal skiagrams taken from patients with clinically confirmed pathology and sagittal imbalance were used. Results. On the basis of quantitative characteristics of the primary spine deformity of a certain clinical case and using the developed algorithm, it is possible to create a model of both a primary deformity and a compensatory response from intact segments of the spine taking into account the influencing factors. This makes it possible to use the proposed kinematic model in scientific research on predicting the course of various types of spinal deformities. Conclusion. The proposed algorithms simulating the development of spinal deformities based on the restoration of the position of the GCM projection reflect their mechanogenesis and can be used to model various pathological conditions of the spine. A complete correction of the deformity does not mean a complete cure, since the required spinal fusion creates a new, prognostically less significant, but pathological situation.

CHAOS IN THE REORIENTATION PROCESS OF A DUAL-SPIN SPACECRAFT WITH TIME-DEPENDENT MOMENTS OF INERTIA

2000 ◽  
Vol 10 (05) ◽  
pp. 997-1018 ◽  
Author(s):  
M. IÑARREA ◽  
V. LANCHARES
Keyword(s):  
Chaotic Behavior ◽  
Initial Conditions ◽  
Center Of Mass ◽  
Melnikov Method ◽  
Moments Of Inertia ◽  
Suitable Parameter ◽  
Nutation Angle ◽  
Principal Axes ◽  
Reorientation Process ◽  
Subharmonic Resonances

We study the spin-up dynamics of a dual-spin spacecraft containing one axisymmetric rotor which is parallel to one of the principal axes of the spacecraft. It will be supposed that one of the moments of inertia of the platform is a periodic function of time and that the center of mass of the spacecraft is not modified. Under these assumptions, it is shown that in the absence of external torques and spinning rotors the system possesses chaotic behavior in the sense that it exhibits Smale's horseshoes. We prove this statement by means of the Melnikov method. The presence of chaotic behavior results in a random spin-up operation. This randomness is visualized by means of maps of the initial conditions with final nutation angle close to zero. This phenomenon is well described by a suitable parameter that measures the amount of randomness of the process. Finally, we relate this parameter with the Melnikov function in the absence of the spinning rotor and with the presence of subharmonic resonances.

Vibration Isolation in a Microgravity Environment

1993 ◽  
Vol 115 (4) ◽  
pp. 477-483
Author(s):  
R. M. Alexander ◽  
C. H. Gerhold ◽  
C. B. Atwood ◽  
J. F. Cordera
Keyword(s):  
Vibration Isolation ◽  
Center Of Mass ◽  
Space Station ◽  
Microgravity Environment ◽  
Isolation System ◽  
Air Jet ◽  
Surrounding Structure ◽  
Jet Control ◽  
Oscillatory Response ◽  
The Mathematical Model

Many in-space research experiments require the microgravity environment attainable near the center of mass of the proposed space station. Since dynamic disturbances to the surrounding structure may undermine an experiment’s validity, isolation of these experiments is imperative. This paper summarizes analytical and experimental work accomplished to develop an isolation system which allows the pay load to float freely within a prescribed boundary while being kept centered with forces generated by small jets of air. An experimental setup was designed and constructed to simulate the microgravity environment In the horizontal plane. Results demonstrate the air jet control system to be effective in managing payload oscillatory response. An analytical model was developed and verified by comparing predicted and measured payload response. The mathematical model is then used to investigate payload response to disturbances likely to be present in the space station.

Spin Rotor Stabilization of a Dual-Spin Spacecraft with Time Dependent Moments of Inertia

1998 ◽  
Vol 08 (03) ◽  
pp. 609-617 ◽  
Author(s):  
V. Lanchares ◽  
M. Iñarrea ◽  
J. P. Salas
Keyword(s):  
Periodic Function ◽  
Center Of Mass ◽  
The Body ◽  
Body Motion ◽  
Time Dependent ◽  
Moments Of Inertia ◽  
Melnikov's Method ◽  
Melnikov’S Method ◽  
Principal Axes

We consider a dual-spin deformable spacecraft, in the sense that one of the moments of inertia is a periodic function of time such that the center of mass is not altered. In the absence of external torques and spin rotors, by means of the Melnikov's method we prove that the body motion is chaotic. Stabilization is obtained by means of a spinning rotor about one of the principal axes of inertia.

scholarly journals Predicting Verification Methods from Natural Language Requirements

2020 ◽  
Author(s):  
Michael Prendergast
Keyword(s):  
Natural Language Processing ◽  
Natural Language ◽  
Language Processing ◽  
Semantic Analysis ◽  
Nearest Neighbor ◽  
Large Set ◽  
Technical Requirements ◽  
Verification Methods ◽  
Natural Language Requirements ◽  
Processing Algorithms

Abstract – A Verification Cross-Reference Matrix (VCRM) is a table that depicts the verification methods for requirements in a specification. Usually requirement labels are rows, available test methods are columns, and an “X” in a cell indicates usage of a verification method for that requirement. Verification methods include Demonstration, Inspection, Analysis and Test, and sometimes Certification, Similarity and/or Analogy. VCRMs enable acquirers and stakeholders to quickly understand how a product’s requirements will be tested.Maintaining consistency of very large VCRMs can be challenging, and inconsistent verification methods can result in a large set of uncoordinated “spaghetti tests”. Natural language processing algorithms that can identify similarities between requirements offer promise in addressing this challenge.This paper applies and compares compares four natural language processing algorithms to the problem of automatically populating VCRMs from natural language requirements: Naïve Bayesian inference, (b) Nearest Neighbor by weighted Dice similarity, (c) Nearest Neighbor with Latent Semantic Analysis similarity, and (d) an ensemble method combining the first three approaches. The VCRMs used for this study are for slot machine technical requirements derived from gaming regulations from the countries of Australia and New Zealand, the province of Nova Scotia (Canada), the state of Michigan (United States) and recommendations from the International Association of Gaming Regulators (IAGR).

Simulation of Nanofibers Movement for Near-Field Electrospinning

2009 ◽  
Vol 60-61 ◽  
pp. 456-460 ◽  
Author(s):  
Hong Lian Wang ◽  
Gao Feng Zheng ◽  
Dao Heng Sun
Keyword(s):  
Narrow Range ◽  
Near Field ◽  
Center Of Mass ◽  
Resistance Force ◽  
Mass Center ◽  
Air Resistance ◽  
Movement Distance ◽  
Initial Spacing ◽  
Electric Field Force ◽  
Final Spacing

NFES is a new and simple way to realize precision-positioning of nanofiber. A model on NFES nanofiber movement is built to analyze the effects of the existed nanofibers which have been collected on the substrate, on the nanofiber’s dropping movement. During electrospinning nanofiber is affected by the electric field force, Coulomb repulsive force, air resistance force gravity and so on. The influence of parameters on the deposition behavior of as-spun nanofiber is discussed. The simulation results show that (i) with charge density increasing, the final spacing between mass center of nanofibers A and B (FSAB) increases and the movement distance of center-of-mass of nanofiber B (MDB) decreases first and then increases; (ii) FSAB increases with applied voltage, but decreased in narrow range with concentration of PEO increasing; (iii) FSAB decreased with the initial spacing between mass center of nanofibers A and B (ISAB) increasing, and then it increases after reaching the minimum. So does ISAB to DMB. This simulation model would improve the controlling of nanofiber in NFES.

Mass Center of Planar Mechanisms Using Auxiliary Parallelograms

1999 ◽  
Vol 121 (1) ◽  
pp. 166-168 ◽  
Author(s):  
A. Gokce ◽  
S. K. Agrawal
Keyword(s):  
Degrees Of Freedom ◽  
Center Of Mass ◽  
Mass Center ◽  
Planar Mechanisms ◽  
Physical Point ◽  
Planar Mechanism ◽  
Test Beds

Center of mass is an important property of a mechanism. In biomechanics, in many studies, one monitors the motion of this point. The center of mass has importance in development of gravity compensated exercise machines and test beds on earth that mimic the behavior of systems in space. In this paper, a method is described where auxiliary parallelograms are added to a planar mechanism to identify the location of the center of mass of the original mechanism. In this procedure, the original and the augmented mechanisms have the same number of degrees-of-freedom. During motion, the center of mass is a physical point which can be monitored or used for purposes motivated from the application.

Inertia Parameters Identification of Motor Assembly for Electric Vehicles Based on Modal Test Method

2013 ◽  
Vol 470 ◽  
pp. 534-538 ◽  
Author(s):  
Li Zhao He ◽  
Peng Yu ◽  
Tong Zhang ◽  
Rong Guo
Keyword(s):  
Error Analysis ◽  
Electric Vehicles ◽  
Center Of Mass ◽  
Moment Of Inertia ◽  
Test Method ◽  
Mass Center ◽  
Test Error ◽  
Modal Test ◽  
Drive Motor ◽  
Inertia Parameters

Inertia parameters are essential for motor assembly mounting design, which mainly includes the mass, center of mass (CM) coordinates, moment of inertia and product of inertia. This paper explains the principle and methods of modal test method. One vehicle drive motor assembly is taken as the research object, its inertia parameters are identified using this modal test method. Finally test error analysis is also performed.

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