Experimental validation of an isoflux Earth coverage with a bimode ARMA antenna on a nanosatellite

2019 ◽  
Vol 12 (1) ◽  
pp. 66-74
Author(s):  
E. Arnaud ◽  
A. Siblini ◽  
A. Bellion ◽  
B. Jecko
Keyword(s):  
Circular Polarization ◽  
Experimental Validation ◽  
Experimental Results ◽  
The Earth ◽  
Manufacturing Problems ◽  
Available Volume

AbstractSpatial telemetry links on nanosatellites require more and more reconfigurable beam antennas to improve the Earth coverage. The bi-mode Agile Radiating Matrix Antenna (8.0–8.4 GHz) was successfully designed to solve such kind of problems by using an isoflux mode associated with a switchable directive one. However, such an antenna introduces some manufacturing problems for the isoflux mode, mainly due to the small available volume on the nanosatellite platform. This paper describes a solution to this problem thanks to the ARMA concept. A comparison between theoretical and experimental results for the isoflux mode in circular polarization is presented to validate the results.

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.

scholarly journals Circularly Polarized Omnidirectional Antenna with Dipole Core and Diagonally Adjoined Parasitic Braces for ISM Band Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Piyapong Dangkham ◽  
Sitthichai Dentri ◽  
Chuwong Phongcharoenpanich ◽  
Prayoot Akkaraekthalin
Keyword(s):  
Circular Polarization ◽  
Dipole Antenna ◽  
Experimental Results ◽  
Antenna Gain ◽  
Circularly Polarized ◽  
Ism Band ◽  
Omnidirectional Antenna ◽  
Quarter Wave ◽  
Radio Band ◽  
Good Agreement

This research proposes a circularly polarized (CP) single-fed omnidirectional dipole antenna operable in 2.45 GHz frequency for the industrial, scientific, and medical (ISM) radio band applications. The proposed antenna consisted of bisectional dipole core, a pair of quarter-wave baluns, and four diagonally adjoined parasitic braces. The bisectional dipole core was utilized to improve the antenna gain and realize omnidirectional radiation pattern, and the quarter-wave baluns were to symmetrize the current on the bisectional core. The four parasitic braces collectively generated circular polarization. In the study, simulations were conducted using CST Microwave Studio and a prototype antenna fabricated. To validate, experiments were carried out, and simulation and experimental results compared. The finding revealed good agreement between the simulation and experimental results. Essentially, in addition to achieving an antenna gain of 2.07 dBic, the proposed CP single-fed omnidirectional antenna is suited to ISM frequency band applications.

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.

A Comparative, Experimental Study of Model Suitability to Describe Vehicle Rollover Dynamics for Control Design

2005 ◽  
Author(s):  
John T. Cameron ◽  
Sean Brennan
Keyword(s):  
Experimental Validation ◽  
Controller Design ◽  
Experimental Testing ◽  
Control Strategies ◽  
Control Design ◽  
Experimental Results ◽  
Dynamics And Control ◽  
Vehicle Rollover ◽  
And Control ◽  
Future Work

This work presents results of an initial investigation into models and control strategies suitable to prevent vehicle rollover due to untripped driving maneuvers. Outside of industry, the study of vehicle rollover inclusive of both experimental validation and practical controller design is limited. The researcher interested in initiating study on rollover dynamics and control is left with the challenging task of identifying suitable vehicle models from the literature, comparing these models with experimental results, and determining suitable parameters for the models. This work addresses these issues via experimental testing of published models. Parameter estimation data based on model fits is presented, with commentary given on the validity of different methods. Experimental results are then presented and compared to the output predicted by the various models in both the time and frequency domain in order to provide a foundation for future work.

Synthesis and characterization of NaAlSi2O6 jadeite under high pressure and high temperature

2014 ◽  
Vol 28 (22) ◽  
pp. 1450175 ◽  
Author(s):  
Fang Biao Wang ◽  
Yong Li ◽  
Ning Chen ◽  
Xiao Peng Jia ◽  
Hong An Ma
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Raw Materials ◽  
Deep Understanding ◽  
Experimental Results ◽  
Synthesis And Characterization ◽  
New Approach ◽  
The Earth ◽  
Amorphous Glass

With Al 2( SiO 3)3 and Na 2 SiO 3 ⋅ 9 H 2 O as raw materials, the NaAlSi 2 O 6 jadeite was synthesized in the temperature range of 1000–1600°C under 5.0 GPa conditions. Amorphous glass materials are entirely converted to crystalline NaAlSi 2 O 6 jadeite at 5.0 GPa and 1450°C. All the experimental results reveal that the properties of synthetic NaAlSi 2 O 6 resemble the natural jadeite very much. The research indicates that we provide a new approach to synthesize NaAlSi 2 O 6 and offer an essential guideline for jewelry, which will be helpful for deep understanding on the origin of natural jadeite and the metamorphism of magma within the Earth.

scholarly journals Geo-neutrinos

2012 ◽  
Vol 2 (2) ◽  
pp. 539-561
Author(s):  
L. Ludhova
Keyword(s):  
Experimental Results ◽  
Radioactive Isotopes ◽  
Future Perspectives ◽  
Short Overview ◽  
Naturally Occurring ◽  
The Earth ◽  
Disciplinary Field

Abstract. Geo-neutrinos, electron anti-neutrinos produced in β-decays of naturally occurring radioactive isotopes in the Earth, are a unique direct probe of our planet's interior. After a brief introduction about the Earth (mostly for physicists) and the very basics about the neutrinos and anti-neutrinos (mostly for geologists), I describe the geo-neutrinos' properties and the main aims of their study. An overview of the latest experimental results obtained by KamLand and Borexino experiments is provided. A short overview of future perspectives of this new inter-disciplinary field is given.

Design and Experimental Validation of Two Cam-Based Force Regulation Mechanisms

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Ming Li ◽  
Wei Cheng ◽  
Ruili Xie
Keyword(s):  
Experimental Validation ◽  
Design Principle ◽  
High Accuracy ◽  
Experimental Results ◽  
Negative Stiffness ◽  
Future Research ◽  
Test Accuracy ◽  
Mechanical Parts ◽  
Regulation Mechanisms ◽  
Noise Phenomenon

Abstract This paper presents the design and experimental validation of two force regulation mechanisms (FRMs) containing a translational cam and a rotational cam, respectively. With the friction-considered profile identification method (FCPIM) to define the cam and through the squeezing between the cam and the spring-supported slider, the FRMs can passively output the desired force over the designed displacement. Under the premise of that the friction coefficient can be accurately obtained, the friction-considered design principle will be significant for the realization of FRMs in actual applications since it is no longer necessary to achieve high accuracy by pursuing the frictionless condition. Hence, the conventional materials and mechanical parts can be directly used to assemble the FRMs without sacrificing the force regulating accuracy. We are highly interested in the actual experimental behavior of the proposed FRMs under the friction-considered condition. Then, prototypes of the two FRMs capable of outputting multiple types of forces including in zero-stiffness, positive and negative stiffness are specially designed, fabricated, and tested quasi-statically. The experimental results verify the correctness of FCPIM since they agree with the design objective well. Meanwhile, the effectiveness of the FCPIM is proved as the errors of the experimental results considering friction is much lower than those ignoring friction. The experiments also show that the noise phenomenon in the testing curves that may affect the judgment of test accuracy can be highly degraded by using more stable and controllable loading tools, which is helpful for future research.

Sign in / Sign up

Export Citation Format

Share Document