The Performance Evaluation of SMA Spring as Actuator for Gripping Manipulation
ABSTRACT: This paper is to
present the evaluation of a TiNi Shape Memory Alloy (SMA) spring as actuator
for the gripping manipulation. The SMA spring employed was a TiNi tensile
spring which has a diameter of 50 mm wire and 350 gram hanging mass. The
gripper fabricated consists of two fingers and each finger is actuated by the
SMA spring. The total angular displacement of the gripper is 300. The power
consumptions, the movements and force generations experimentations have been
conducted. The DC signal and PWM signal with 12, 12Hz, 25Hz, 125Hz, 250Hz and
the 1150Hz have been employed for driving the SMA. The experimental results
indicated that the 125Hz of PWM signal was likely to be had a better performance
than the other signals. The 125Hz PWM signal generated faster movement, lower
power consumption, and constant rate of force. In this study, closed-loop
control for gripping manipulation was
also conducted. The close loop controller used is PID controller. The
Ziegler-Nichols method has been used to predict the optimal gain of the
controller, but the best performance was determined by experimentally tuning of
the gains. The experimental results indicated that the PID controller is likely
to be reliable controller for gripping manipulation of the SMA spring. To
obtain the better performance, it is important to consider the SMA cooling
responses and the long time of retain in certain position of the gripper.
Author: Made Andik Setiawan
Journal Code: jptlisetrogg070001
