Derivation and Experimental Validation of the Equations of Motion of Magnetic Pendulums

2021 ◽  
pp. 1-7
Author(s):  
Razieh Saeidi Hosseini ◽  
Glenn R. Heppler ◽  
Eihab Abdel-Rahman
Keyword(s):  
Social Networks ◽  
Experimental Validation ◽  
Equilibrium Points ◽  
Equations Of Motion ◽  
Experimental Results ◽  
Quantum Communications

Abstract A series of coaxial magnetic pendulums is studied as a simple physical surrogate for more general nonlinearly-coupled almost-identical resonators that arise in quantum communications and the dynamics of social networks. The equations of motion for a series of coaxial magnetic pendulums are derived and the solution is compared to experimental results. The equilibrium points and their stability are also determined.

Experimental Validation of a Walking Model for Planar Bipeds With Curved Feet

2011 ◽  
Author(s):  
Anne E. Martin ◽  
James P. Schmiedeler
Keyword(s):  
Mathematical Model ◽  
Humanoid Robot ◽  
Experimental Validation ◽  
Equations Of Motion ◽  
Experimental Results ◽  
Bipedal Walking ◽  
Human Gait ◽  
Bipedal Robots ◽  
Simplifying Assumptions ◽  
The Mathematical Model

Bipeds with curved feet typically require less energy for walking than do point- or flat-footed bipeds, and they tend to mimic human gait more closely. Thus, understanding the effects of curved feet on bipedal walking gaits has the potential to improve both humanoid robot efficiency and human rehabilitation. This paper derives the equations of motion for planar bipeds with curved feet under the assumption, among others, of instantaneous transfer of support between the legs. The paper then verifies the mathematical model by comparing the results of simulation to previous experimental results for two very different bipedal robots — McGeer’s two-link, passive dynamic walker traversing a decline and the five-link, actuated biped ERNIE walking on a treadmill with a supporting boom. In both cases, the results from simulation match the experimental results very well despite the simplifying assumptions, indicating that the mathematical model captures the dominate dynamics of bipedal robots with curved feet.

Conical SNA using fuzzy k-medoids based on user experience

2021 ◽  
pp. 002072092098849
Author(s):  
Poonam Rani ◽  
MPS Bhatia ◽  
Devendra K Tayal
Keyword(s):  
Social Networks ◽  
Social Network ◽  
User Experience ◽  
Three Dimensional ◽  
Experimental Results ◽  
Dynamic Parameters ◽  
Clustering Method ◽  
Cone Model ◽  
Intelligent Approach ◽  
Conical Model

The paper presents an intelligent approach for the comparison of social networks through a cone model by using the fuzzy k-medoids clustering method. It makes use of a geometrical three-dimensional conical model, which astutely represents the user experience views. It uses both the static as well as the dynamic parameters of social networks. In this, we propose an algorithm that investigates which social network is more fruitful. For the experimental results, the proposed work is employed on the data collected from students from different universities through the Google forms, where students are required to rate their experience of using different social networks on different scales.

On Robe’s restricted problem with a modified Newtonian potential

2020 ◽  
Vol 18 (01) ◽  
pp. 2150005 ◽  
Author(s):  
Elbaz I. Abouelmagd ◽  
Abdullah A. Ansari ◽  
M. H. Shehata
Keyword(s):  
Equilibrium Points ◽  
Equations Of Motion ◽  
Underwater Vehicles ◽  
Newtonian Potential ◽  
Second Primary ◽  
The Moon ◽  
Primary Body ◽  
Out Of Plane ◽  
Robe’S Restricted Problem ◽  
Dust Grain

We analyze the existence of equilibrium points for a particle or dust grain in the framework of unperturbed and perturbed Robe’s motion. This particle is moving in a spherical nebula consisting of a homogeneous incompressible fluid, which is considered as the primary body. The second primary body creates the modified Newtonian potential. The perturbed mean motion and equations of motion are found. The equilibrium points (i.e. collinear, noncollinear and out–of–plane points), along with the required conditions of their existence are also analyzed. We emphasize that this analysis can be used to study the oscillations of the Earth’s core under the attraction of the Moon and it is also applicable to study the motion of underwater vehicles.

scholarly journals Recognition of Compromised Accounts on Twitter

2015 ◽  
Author(s):  
Rodrigo Igawa ◽  
Alex Almeida ◽  
Bruno Zarpelão ◽  
Sylvio Jr
Keyword(s):  
Social Networks ◽  
Online Social Networks ◽  
Experimental Results ◽  
Writing Style ◽  
Authorship Verification

In this work, we propose an approach for recognition of compromised Twitter accounts based on Authorship Verification. Our solution can detect accounts that became compromised by analysing their user writing styles. This way, when an account content does not match its user writing style, we affirm that the account has been compromised, similar to Authorship Verification. Our approach follows the profile-based paradigm and uses N-grams as its kernel. Then, a threshold is found to represent the boundary of an account writing style. Experiments were performed using a subsampled dataset from Twitter. Experimental results showed that the developed model is very suitable for compromised recognition of Online Social Networks accounts due to the capability of recognize user styles over 95% accuracy.

scholarly journals On the Stability of Collinear Points of the RTBP with Triaxial and Oblate Primaries and Relativistic Effects

2021 ◽  
pp. 56-73
Author(s):  
S. E. Abd El-Bar
Keyword(s):  
Characteristic Equation ◽  
Body Problem ◽  
Equilibrium Points ◽  
Equations Of Motion ◽  
Relativistic Effects ◽  
Three Body Problem ◽  
Total Potential ◽  
The Mean ◽  
The Stability ◽  
Three Body

Under the influence of some different perturbations, we study the stability of collinear equilibrium points of the Restricted Three Body Problem. More precisely, the perturbations due to the triaxiality of the bigger primary and the oblateness of the smaller primary, in addition to the relativistic effects, are considered. Moreover, the total potential and the mean motion of the problem are obtained. The equations of motion are derived and linearized around the collinear points. For studying the stability of these points, the characteristic equation and its partial derivatives are derived. Two real and two imaginary roots of the characteristic equation are deduced from the plotted figures throughout the manuscript. In addition, the instability of the collinear points is stressed. Finally, we compute some selected roots corresponding to the eigenvalues which are based on some selected values of the perturbing parameters in the Tables 1, 2.

Determination of Stability Derivatives by Impulse-Response Techniques

1977 ◽  
Vol 14 (02) ◽  
pp. 265-275
Author(s):  
Carl A. Scragg
Keyword(s):  
Memory Effect ◽  
Impulse Response ◽  
Traditional Method ◽  
Equations Of Motion ◽  
Experimental Results ◽  
Regular Motion ◽  
Stability Derivatives ◽  
The Stability ◽  
Derivatives Of

This paper presents a new method of experimentally determining the stability derivatives of a ship. Using a linearized set of the equations of motion which allows for the presence of a memory effect, the response of the ship to impulsive motions is examined. This new technique is compared with the traditional method of regular-motion tests and experimental results are presented for both methods.

scholarly journals Design and Experimental Validation of a 3-DOF Force Feedback System Featuring Spherical Manipulator and Magnetorheological Actuators

Actuators ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 19 ◽  
Author(s):  
Bao Tri Diep ◽  
Ngoc Diep Nguyen ◽  
Thanh T. Tran ◽  
Quoc Hung Nguyen
Keyword(s):  
Control System ◽  
Shoulder Joint ◽  
Experimental Validation ◽  
Force Feedback ◽  
Feedback System ◽  
Radial Force ◽  
Experimental Results ◽  
The Other ◽  
Sliding Joint ◽  
End Effectors

This research focuses on the development of a new 3-DOF (Degree of Freedom) force feedback system featuring a spherical arm mechanism and three magnetorheological (MR) brakes, namely two rotary MR brakes and one linear MR brake. The first rotary MR brake is integrated in the waist joint to reflect the horizontal tangent force, the other rotary MR brake is integrated in the shoulder joint to reflect the elevation tangent force, while the linear MR brake is integrated in the sliding joint of the arm to reflect the radial force (approach force). The proposed configuration can reflect a desired force to the operator at the end-effectors of the arm independently in 3 DOFs by controlling the current applied to the coils of the MR brakes. After the introduction, the configuration of the proposed force feedback system is presented. Afterward, the design and conducted simulation of the MR brakes for the systems are provided. The prototype of the force feedback system, which was manufactured for the experiment, is then presented as well as some of the obtained experimental results. Finally, the proposed control system is presented and its implementation to provide a desired feedback force to the operator is provided.

Thermal Behavior Evaluation During Mechanical Design: Validation of Thermal Numerical Gearbox Models

2000 ◽  
Author(s):  
Lionel Manin ◽  
Daniel Play
Keyword(s):  
Steady State ◽  
Experimental Validation ◽  
Mechanical Design ◽  
Numerical Models ◽  
Side Wall ◽  
Experimental Results ◽  
Transient Temperature ◽  
Transmitted Power ◽  
Thermal Models ◽  
Thermal Network Method

Abstract In todays mechanical design, static and dynamic numerical models are widely used, and thermal models are needed to make robust design. Thermal models, based on the thermal network method, are now available. Several hypotheses are made as physical phenomena are complex and experimental validation is necessary. A thermal model of gearbox has been already presented and compared to few experimental results that had allowed global validation of the model. Now, the experimental validation is concerned with thermal transient and steady state behavior of gearbox versus transmitted power and lubrication conditions in order to finely validate the model. The test gearbox is compound of 3 spur gears supported by 6 spherical roller bearings, a housing and a lubrication circuit cooled by an oil-air exchanger. The maximum transmitted power is 500 kW. Gears, bearings, housing, shafts, and the lubrication circuit have been equipped with thermocouples, flux-meters and flow-meters. Heat flux were measured on the internal and external side walls of the housing. Oil flowing on a side wall has been measured. Experiments were run under several transmitted powers and oil flows at meshing. Thermal map at steady state and transient temperature rises of technological elements are obtained for each test. Finally, transient temperature rises and steady state from numerical and experimental results are compared. The comparison shows a good agreement, and the importance of taking into account oil flowing on the inside walls of the housing is brought to the fore. The difficulty of evaluating the oil flowing on the internal walls of a housing is discussed and illustrated with numerical results.

Experimental Validation of Towed Underwater Cable Model

2019 ◽  
Author(s):  
Jan Vidar Grindheim ◽  
Antonio Carlos Fernandes ◽  
Joel Sena Sales Junior ◽  
Inge Revhaug
Keyword(s):  
Steady State ◽  
Experimental Validation ◽  
Experimental Results ◽  
Experimental Setup ◽  
Two Dimensional ◽  
Cable Model ◽  
Governing Equations ◽  
Current Channel ◽  
Steady State Condition ◽  
Wet Weight

Abstract Towed underwater cable models have been validated using experimental results performed in the current channel at Laboratório de Ondas e Correntes (LOC) at COPPE/UFRJ, Rio de Janeiro. The numerical simulators utilize a Finite Difference Method to solve the Partial Differential Equations describing the dynamics of a towed underwater cable under tension. A non-dimensional analysis of the system dynamics for the two-dimensional case has been performed, with non-dimensional governing equations being presented. The experimental setup consists of two cable sections of ∼1.5 m length each, the first having 3 mm diameter and slightly positive wet weight while the second section has 2.5 mm diameter and slight negative wet weight. With the cable in steady-state condition, the towpoint is moved 0.50 m sideways and the time for the cable to return to straight tow is measured. Further, the cable depths at midpoint and tail are measured in steady-state. Experiments are performed at currents ranging from 0.17 to 0.47 m/s. The presented experimental results are compared to the numerical results. Reasonable agreements are obtained.

Development and Validation of the Kinematic Analysis of a Low Low-Cost 4-Link Robot

2015 ◽  
Vol 789-790 ◽  
pp. 626-635
Author(s):  
O. Olatunbosun Ajayi ◽  
E. Okafor Onyemaechi ◽  
Onwudiwe Obumneme
Keyword(s):  
Kinematic Analysis ◽  
Robot Control ◽  
Third World ◽  
Experimental Validation ◽  
System Development ◽  
Low Cost ◽  
Experimental Results ◽  
Computer Interface ◽  
Robot System ◽  
Development And Validation

In this paper, we describe the development and validation of the kinematic analysis of a low low-cost 4-link robot the first of its kind in Nigeria. This study comprises the following key tasks which describe the methodology for the robot development: design and kinematic analysis of the robot mechanism, construction/fabrication and assembly of the robot, system development (computer interface with the robot) and experimental validation of the robot control. The goal of this robot is to pick an object and drop the object in a specified position. The algorithm to control the robot on the computer was coded in Java and simulated in MATLAB/Simulink platform. The robot was experimentally verified and the results are presented in this paper. The experimental results show that robot development is feasible in Nigeria. The contribution of this study will enhance and promote robot control and development in Nigeria and developing third world countries.

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