The Sandiford 2.1-m Cassegrain echelle spectrograph for McDonald Observatory - Optical and mechanical design and performance

1993 ◽  
Vol 105 ◽  
pp. 881 ◽  
Author(s):  
James K. McCarthy ◽  
Brendan A. Sandiford ◽  
David Boyd ◽  
John Booth
Keyword(s):  
Mechanical Design ◽  
Echelle Spectrograph ◽  
And Performance

scholarly journals A 4-DOF Upper Limb Exoskeleton for Physical Assistance: Design, Modeling, Control and Performance Evaluation

2021 ◽  
Vol 11 (13) ◽  
pp. 5865
Author(s):  
Muhammad Ahsan Gull ◽  
Mikkel Thoegersen ◽  
Stefan Hein Bengtson ◽  
Mostafa Mohammadi ◽  
Lotte N. S. Andreasen Struijk ◽  
...  
Keyword(s):  
Upper Limb ◽  
Tracking Control ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Mechanical Design ◽  
Trajectory Tracking Control ◽  
Upper Limb Exoskeleton ◽  
And Performance ◽  
Physically Disabled People ◽  
Human Upper Limb

Wheelchair mounted upper limb exoskeletons offer an alternative way to support disabled individuals in their activities of daily living (ADL). Key challenges in exoskeleton technology include innovative mechanical design and implementation of a control method that can assure a safe and comfortable interaction between the human upper limb and exoskeleton. In this article, we present a mechanical design of a four degrees of freedom (DOF) wheelchair mounted upper limb exoskeleton. The design takes advantage of non-backdrivable mechanism that can hold the output position without energy consumption and provide assistance to the completely paralyzed users. Moreover, a PD-based trajectory tracking control is implemented to enhance the performance of human exoskeleton system for two different tasks. Preliminary results are provided to show the effectiveness and reliability of using the proposed design for physically disabled people.

scholarly journals A High Resolution Spectrograph at Weihai Observatory

2012 ◽  
Vol 8 (S293) ◽  
pp. 400-402
Author(s):  
Dongyang Gao ◽  
Dayong Ren
Keyword(s):  
High Resolution ◽  
Echelle Spectrograph ◽  
Metal Abundance ◽  
And Performance

AbstractWeihai Echelle Spectrograph (WES) is the first the fiber-fed echelle spectrograph in China. WES can provide data for the studies of metal abundance of stars, exoplanets researches and asteroseismology, etc. A brief description of its design and performance is given.

Mechanical Design, Additive Manufacturing, and Performance of Equal Volume Metamaterials

2021 ◽  
Author(s):  
Richárd Horváth ◽  
Vendel Barth ◽  
Viktor Gonda ◽  
Mihály Réger ◽  
Imre Felde
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Absorption ◽  
Mechanical Design ◽  
Area Under The Curve ◽  
Cell Number ◽  
Element Analysis ◽  
Cross Sectional ◽  
Unit Cells ◽  
And Performance

Abstract In this paper, we study the energy absorption of metamaterials composed of unit cells whose special geometry makes the cross-sectional area and the volume of the bodies generated from them constant (for the same enclosing box dimensions). After a parametric description of such special geometries, we analyzed by finite element analysis the deformation of the metamaterials we have designed during compression. We 3D printed the designed metamaterials from plastic to subject them to real compression. The results of the finite element analysis were compared with the real compaction results. Then, for each test specimen, we plotted its compaction curve. By fitting a polynomial to the compaction curves and integrating it (area under the curve), the energy absorption of the samples can be obtained. As a result of these investigations, we drew a conclusion about the relationship between energy absorption and cell number.

A Robotic Arm for Electric Scooters

2011 ◽  
pp. 94-109
Author(s):  
Samuel N. Cubero
Keyword(s):  
Frail Elderly ◽  
Mechanical Design ◽  
People With Disabilities ◽  
Robotic Arm ◽  
Robot Arm ◽  
Self Sufficiency ◽  
Electric Scooter ◽  
Manipulator Arm ◽  
And Performance ◽  
Three Degree Of Freedom

This chapter describes the mechanical design, manufacture and performance of a three-degree-of-freedom manipulator arm and gripper that can be attached to a mobile vehicle or electric scooter. Known by the acronym “ESRA”, or “Electric Scooter Robot Arm”, this device can be remotely or automatically controlled to pick up and retrieve heavy objects, such as books or grocery products, from high shelves or difficult-to-reach locations. Such tasks are often considered to be arduous or even impossible for the frail elderly and people with disabilities. This chapter describes one example of how the combination of mechanical and electronic engineering technology can be used to perform physically strenuous tasks and enable the frail elderly and people with disabilities to enjoy a greater degree of self-sufficiency, independence and physical productivity. It includes the design process for robotic arm manipulators and actuators. It also provides a brief overview of existing “state of the art” robotic and machine vision technologies, and how these can be used to perform many everyday domestic or household chores.

Structural Integrity and Mechanical Design of a Probe of High Pressure and High Temperature for Oil Wells Applying Finite Elements Tools

2014 ◽  
Author(s):  
Erik Rosado Tamariz ◽  
Rito Mijarez Castro ◽  
Agustín Javier Antúnez Estrada ◽  
Alfonso Campos Amezcua ◽  
David Pascacio Maldonado ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Structural Integrity ◽  
Mechanical Design ◽  
Pressure Vessels ◽  
Oil Wells ◽  
Principal Stresses ◽  
Commercial Code ◽  
And Performance ◽  
Mechanical Elements

Measurement of high pressure and high temperature (HPHT) tools is regularly carried out in the hydrocarbons sector to determine not only the characteristics and performance of fluids inside the well, but also to evaluate the mechanical condition of the pipes and the automation of production. The mechanical features of these tools are significantly influenced by the mechanical design of the structure, which eventually affects their performance and integrity. This paper describes the design process and the analysis of the structural integrity of a HPHT measuring tool for oil wells in its sensors section. The classical theories of mechanical design and specifications of the ASME boilers and pressure vessels code were used. The study is performed for several operation variables in a numerical model using a commercial code of finite element method to determinate the maximum principal stresses, total displacements and safety factor in the mechanical elements that form the device. The numerical results were compared with the experimental data source from the laboratory tests.

Hanle echelle spectrograph: design and performance

2018 ◽  
Author(s):  
Amit S. Kumar ◽  
Sriram Padmanaban Nadar ◽  
Arun Surya ◽  
Sivarani Thirupathi ◽  
Sunetra Giridhar ◽  
...  
Keyword(s):  
Echelle Spectrograph ◽  
And Performance

scholarly journals Simulation and Experimental Investigation of a Two-Stage Magnetic Precession Gear

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1838
Author(s):  
Lukasz Macyszyn ◽  
Cezary Jedryczka ◽  
Adam Myszkowski
Keyword(s):  
Mechanical Design ◽  
Maximum Load ◽  
Mechanical Efficiency ◽  
Gear Ratio ◽  
Maximum Efficiency ◽  
The Finite Element Method ◽  
Two Stage ◽  
Fem Model ◽  
And Performance ◽  
Main Components

Gears are common and important components of many types of propulsion systems applied in mechanical engineering. The aim of this paper is to present the mechanical design and performance analysis of a novel two-stage magnetic precession gear (MPG). The main advantage of the proposed design is the ability to obtain higher transmission ratios than other currently known magnetic gear types. A detailed analysis of the performance of the MPG was carried out employing a developed numerical model of the magnetic field in the proposed gear. The MPG model is based on the finite element method (FEM) and allows determining the relations between the torque acting on the main components of the gear, load angles, and air-gap lengths. To validate the developed FEM model, the prototype of an MPG with a 1/144 gear ratio was built and tested. The experiments were also focused on determining the mechanical efficiency as well as the influence of rotational speed and lengths of air gaps on the maximum load torque. The tests indicated that the maximum efficiency of the studied MPG is about 30%, which is comparable to the efficiency of mechanical two-stage precession gears with face meshing.

Mechanical design and performance of 74-cm aperture third harmonic crystal arrays

1984 ◽  
Author(s):  
Burt C. Johnson ◽  
J. D. Williams ◽  
M. A. Summers ◽  
David Milam ◽  
R. C. Murray
Keyword(s):  
Mechanical Design ◽  
Third Harmonic ◽  
Harmonic Crystal ◽  
And Performance
Sign in / Sign up

Export Citation Format

Share Document