The Investigation of PID Controller for MEMS Gripper

Abstract

This paper is to present the characterization of MEMS material gripper actuated by PID controller. The MEMS material actuator employed was a TiNi Shape Memory Alloy (SMA) tensile spring which has a diameter of 50 mm wire and 350 gram hanging mass. The gripper fabricated consists of two fingers and the total angular displacement of the gripper is 300. Several experiments of the gripper performance have been conducted. The pulse-width modulation (PWM) with a 125Hz of frequency has been employed to drive the spring. The optimal gain range parameter was predicted by using Ziegler-Nichol method calculated from open loop control responses. The experimentally tuning responses of those parameters have been recorded and then evaluated by employing LabView program. By analyzing the responses, it can be stated that the optimal gain parameter combination are varies from 6 to 10 for P gain, 0.5 up to 1 for I gain and 0.5 up to 10 for D gain controller. By introducing the PID controller, the better performance actuation of MEMS gripper can be reached. PID controller is likely to be reliable controller for positioning control in MEMS applications.