Simultaneous parametric optimization of IPMC actuator for compliant gripper

Abstract

Ionic Polymer Metal Composite (IPMC) exhibits artificial muscle behavior while subjected to change in voltage, frequency and doping solutions. Here, an attempt has been made to actuate a miniscule compliant gripper by a pair of IPMC strips. To obtain substantial displacement and force to actuate the compliant gripper, a full factorial experimental layout was laid by considering three levels of voltage (1.5 V-3 V-4.5 V), frequencies (0.1 Hz-0.01 Hz-0.001 Hz) and doping solutions (KCl, NaCl and Distilled Water). Grey Relational Analysis was adopted to turn multi-objectives (force and displacement) into a single objective and the best parametric combination was found as ds-1-f+1-v+1 [KCl 1.5 (N)-0.001 Hz-4.5 V]. Response Surface Modeling (RSM) and ANOVA was adopted to correlate the force and displacement in terms of the process parameters (Voltage and Frequency). At the optimized parametric condition, IPMC strips provided actuating force and displacement of 4.8 mN and 3.24 mm respectively. A small compliant two-jaw gripper was modeled in CATIA V5-R20 and through ANSYS 14.0, it was observed that, at 1.5 mm gripper thickness, each jaw-tip flexed by 1.56 mm. Afterwards, the gripper was fabricated with PDMS material and IMPCs were able to flex each jaw by 0.87 mm. The gripper was observed to grip objects with maximum of 1.247 gms of weight.