Optimisation of Ni–Ti shape memory alloy response time by transient heat transfer analysis

2012 ◽  
Vol 35 ◽  
pp. 655-663 ◽  
Author(s):  
S. Huang ◽  
M. Leary ◽  
T. Ataalla ◽  
K. Probst ◽  
A. Subic
Keyword(s):  
Heat Transfer ◽  
Shape Memory Alloy ◽  
Response Time ◽  
Shape Memory ◽  
Heat Transfer Analysis ◽  
Transient Heat Transfer

Transient heat-transfer analysis for sub-scale noz...

2005 ◽  
Author(s):  
Dr. Jae-Seok Yoo ◽  
Mr. Byung-Hun Kim ◽  
Dr. Young-Soon Jang ◽  
Dr. Yeong-Moo Yi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Analysis ◽  
Transient Heat Transfer

Backstepping Control of a Shape Memory Alloy Actuated Robotic Arm

2005 ◽  
Vol 11 (3) ◽  
pp. 407-429 ◽  
Author(s):  
M. Elahinia ◽  
J. Koo ◽  
M. Ahmadian ◽  
C. Woolsey
Keyword(s):  
Heat Transfer ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Sliding Mode ◽  
Angular Position ◽  
Robotic Arm ◽  
Transfer Model ◽  
Nonlinear Controller ◽  
Model Based ◽  
The Wire

This paper investigates a nonlinear controller designed to stabilize a single-degree-of-freedom rotary shape memory alloy (SMA) actuated robotic arm. To this end, a bias-type robotic arm was built using 150 pm Flexinol SMA wire. This robot is designed to lift and position lightweight objects. Upon complete phase transformation, the SMA wire actuates the robot to rotate up to 1350. A linear spring is used to extend the wire to its original length because the SMA wire can only apply force in one direction. To measure the angular position of the robotic arm, an optical rotary encoder was used. To stabilize the robot, a model-based controller was developed. The controller incorporates the SMA actuated robot model with nonlinear control techniques. The model consists of three parts: the dynamics/kinematics of the arm, the thermoruechanical behavior of SMA wire, and the heat transfer model of the wire. The model-based backstepping controller determines the applied voltage to the SMA wire for positioning the arm at the desired angle by first calculating the wire's stress to stabilize the arm. The voltage to the SMA wire is then calculated based on the desired stress and the SMA's thermomechanical and heat transfer models. A series of simulations were performed to investigate stabilizing performance of the controller. Moreover, other issues such as robustness of the control design was evaluated. The results show that the control algorithms is able to globally and asymptotically stabilize the robot. The results further indicate that the sliding mode control has better robustness properties.

Transient Heat Transfer Analysis of Freeze Plate Structures Cooled by Nanofluids

2006 ◽  
Author(s):  
Rong-Yuan Jou
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Nano Particles ◽  
Heat Transfer Analysis ◽  
Transient Heat Transfer ◽  
Innovative Technology ◽  
Transfer Enhancement ◽  
Left Hand ◽  
Smooth Channel ◽  
Transport Problems

Heat transfer enhancement by nanofluids is an emerging and innovative technology for traditional heat transfer problems. However, researches of nanofluids for refrigeration applications are rare either theoretically or experimentally. In this paper, the physical model of a freezing chucker is considered as a two-dimensional domain which is consist of the top and bottom copper plates, and a channel for flowing of copper nanofluids. Inlet flow passes through the left hand side and exhausts to the outlet at right hand side. Three kinds of transverse rib structures, e/Dh = 0.1, 0.2, 0.3, are attached on the internal top wall of the channel for heat transfer enhancement of the coolant flows. To investigate this problem, the transient heat transfer of this channel flow is analyzed and transport problems are solved numerically for the ethylene-glycol (EG) based nanofluids mixture of copper nano-particles with volume fractions of 0%, 0.5%, 1%, 5%, respectively. The smooth channel problem is analyzed and compared to the ribbed channel problem. Analyses of the highest decay rate, the lowest temperature, and temperature distributions of the top-plate surface of a freezing chucker are shown.

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