Nonlinear backstepping control of an electrohydraulic material testing system

2002 ◽  
Author(s):  
S.J. Lee ◽  
Tsu-Chin Tsao
Keyword(s):  
Material Testing ◽  
Backstepping Control ◽  
Testing System ◽  
Nonlinear Backstepping Control

NONLINEAR BACKSTEPPING CONTROL FOR THE FUEL DIFFUSION LAG IN FUSION REACTORS

2002 ◽  
Vol 35 (1) ◽  
pp. 113-118 ◽  
Author(s):  
Eugenio Schuster ◽  
Miroslav Krstić ◽  
George Tynan
Keyword(s):  
Backstepping Control ◽  
Fusion Reactors ◽  
Nonlinear Backstepping Control

scholarly journals Nonlinear Backstepping Control of Permanent Magnet Synchronous Motor with Rotor Speed and Position Estimation

2018 ◽  
Vol 3 (3) ◽  
pp. 133-142
Author(s):  
Abderrahmen KIRAD ◽  
Said Grouni ◽  
Omar MECHALI
Keyword(s):  
Permanent Magnet ◽  
High Performance ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Backstepping Control ◽  
Position Estimation ◽  
Nonlinear Feedback ◽  
Precise Knowledge ◽  
The Stability ◽  
Nonlinear Backstepping Control

This paper presents a nonlinear backstepping control strategy used to ensure good dynamic behavior, high performance and the stability of the permanent magnet synchronous motor (PMSM). However, this control requires the precise knowledge of certain variables (speed, torque and position) that are difficult to access or sensors require additional mounting space, reduce reliability, increase the cost of the engine, and make maintenance difficult. Thus, an Extended Kalman Filter (EKF) approach is proposed for the estimation of speed and rotor position in the PMSM. The interesting simulation results obtained which are subjected to the load perturbation show very well the efficiency and the good performance of the nonlinear feedback control proposed and simulated in Matlab-Simulink.

Biomechanics of the wrist after proximal row carpectomy in cadavers

2009 ◽  
Vol 35 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Y.-L. Zhu ◽  
Y.-Q. Xu ◽  
J. Ding ◽  
J. Li ◽  
B. Chen ◽  
...  
Keyword(s):  
Sharp Decrease ◽  
Material Testing ◽  
Testing System ◽  
Average Pressure ◽  
Proximal Row Carpectomy ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Fresh Frozen ◽  
Pressure Sensitive Film ◽  
Lunate Fossa

We investigated the biomechanics of the radiocapitate joint after a proximal row carpectomy in six fresh-frozen cadaver wrists using super-low-pressure-sensitive film on a material testing system. The average pressure within the lunate fossa increased significantly from 23.2 to 136.4 N/cm2 with a sharp decrease in the contact area from 2.08 to 0.30 cm2 after a proximal row carpectomy. The cartilage of the proximal capitate had four sub-facets and therefore was not as smooth as the normal proximal lunate. We found that the wrist was overloaded after a proximal row carpectomy and the main cause was the anatomical mismatch of the radiocapitate articulation.

In-Situ Electron Microscopy Testing of 1-D Nanostructures

2008 ◽  
Author(s):  
Horacio D. Espinosa
Keyword(s):  
Tensile Testing ◽  
Material Testing ◽  
Testing System ◽  
Device Performance ◽  
Nanoscale Material ◽  
The Past ◽  
In Situ Electron Microscopy ◽  
Experimental Approaches ◽  
Walled Cnts

Over the past decade, there has been a substantial thrust to reduce the size of electronic and electromechanical systems to the nano scale by fabricating devices out of thin films, carbon nanotubes (CNTs) and nanowires (NWs). In these applications, a thorough understanding of material mechanical, electrical and thermal properties as well as device performance and reliability requires the development of novel experimental approaches. In this presentation the design, microfabrication and operation of a MEMS based nanoscale material testing system (n-MTS, see Fig. 1) will be presented. Results obtained from in-situ SEM and TEM tensile testing of NWs and CNTs will be discussed. We will show that TEM imaging is required to properly assess the modulus and strength of multi-walled CNTs (MWCNTs) and demonstrate that the assumption of outer shell failure is not accurate in most cases. We will also discuss a change in failure mode as a function of electron and ion radiation.

THE MECHANICAL BEHAVIOUR OF COBALT SUPERALLOYS WITH TI ELEMENT ADDITION

2013 ◽  
Vol 37 (3) ◽  
pp. 365-373
Author(s):  
Tao-Hsing Chen
Keyword(s):  
Strain Rate ◽  
Mechanical Response ◽  
Rate Sensitivity ◽  
Material Testing ◽  
Testing System ◽  
Strain Rates ◽  
Strengthening Effect ◽  
Microstructural Characteristics ◽  
Element Addition ◽  
Increasing Temperature

The influence of titanium element, strain rate and tested temperatures on the mechanical properties and microstructural characteristics will be investigated in this paper. These cobalt-based superalloys are tested using material testing system (MTS) at strain rates of 10−3, 10−2 and 10−1 s−1 and at temperatures of 700, 500 and 25° C, respectively. It is found that the flow stress increases with increasing strain rate and Ti, but decreases with increasing temperature. Furthermore, the strain rate sensitivity increases with increasing strain rate, but decreases with increasing temperature. The microstructural observations confirm that the mechanical response of the cobalt superalloy specimens is directly related to the effects of the titanium contents, strain rate and temperature on the evolution of the microstructure. It can be observed that the strengthening effect in cobalt-based superalloys is a result primarily of dislocation multiplication. The dislocation density increases with increasing strain rate, but decreases with increasing temperature.

Comparison of Two Fixation Methods of Oblique Lesser Metatarsal Osteotomies: A Biomechanical Study

1995 ◽  
Vol 16 (7) ◽  
pp. 437-439 ◽  
Author(s):  
Mark P. Slovenkai ◽  
Daniel Linehan ◽  
Linda McGrady ◽  
Tae-Hong Lim ◽  
Gerald F. Harris ◽  
...  
Keyword(s):  
Internal Fixation ◽  
Screw Fixation ◽  
Material Testing ◽  
Biomechanical Study ◽  
Testing System ◽  
Human Cadaver ◽  
Kirschner Wires ◽  
Fixation Methods ◽  
Single Screw ◽  
Fresh Frozen

Two methods of internal fixation of oblique lesser metatarsal osteotomies were compared biomechanically using fresh-frozen human cadaver bones. Osteotomies were made obliquely through the metatarsal shafts and fixed with either crossed Kirschner wires or a single AO screw using the lag technique. The specimens were then fixed at their proximal end and loaded to failure using an axial torsion material testing system (MTS, Minneapolis, MN). Load displacement curves were obtained and the stiffness of the constructs was determined. Single-screw fixation was found to be significantly stiffer than the crossed wire configuration ( P < .01). Single-screw fixation resulted in a stiffness of 211.2 ± 111.7 N/cm (mean ± SD), while stiffness of the crossed wire configuration averaged 56.9 ± 25.1 N/cm.

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