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 30 0 . 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.

Micro Electromechanical Systems (MEMS) Based Microfluidic Devices for Biomedical Applications

“…The hysteresis width ΔT of 9 °C was observed. Setiawan [ 76 ] reported the performance assessment of SMA spring as actuator for gripping manipulation. The SMA actuator was a TiNi tensile spring with diameter of 50 mm wire and 350 gram hanging mass.…”

Numerical Approaches for Recovering the Deformable Membrane Profile of Electrostatic Microdevices for Biomedical Applications

“…Concerning the design of a micropump, the actuator is one of the most important devices since it converts the applied external energy (electrical, thermal, …) into movement of the deformable element (usually, a membrane). The mechanical micropumps (piezoelectric [ 12 ], electrostatic [ 13 ], thermopneumatic [ 14 ], electromagnetic [ 15 ], bimetallic [ 16 ], ion conductive [ 17 ], phase change [ 18 ], shape memory alloy polymer films [ 19 ]) require an actuator for pumping; usually, they consist of a pumping chamber separated by a deformable diaphragm so the fluid flows by means of oscillations which generate pressures depending on the volume of the stroke inside the chamber produced by the actuator. Of course, performance is severely limited by the mechanical components.…”