Actuation characteristics and experimental identification of IPMC actuator for underwater biomimetic robotic application

Abstract

Traditionally underwater robotic devices are driven with the help of hydraulic systems or motors. However, with the current advancement in technology and inclination towards smart structures and miniature designs, various new actuators are being utilized. Ionic polymer-metal composites (IPMC) are the smart materials that come under the category of Ionic Electro-active polymers are considered as the best suitable soft actuator material for robotic devices in the field of military, aerospace and medical applications. The soft actuator’s actuation characteristics are explored in an underwater environment using data acquisition from LabView and laser vibrometer for providing the input voltage to the IPMC and to measure the tip deflection of IPMC actuator respectively. Proportional, Integral and Derivative (PID) closed-loop response using Ziegler Nichols tuning method for getting controller gains is presented through MATLAB/Simulink simulation for better actuation based on desired output response of the actuated IPMC. An evolutionary optimization technique, Particle swarm optimization (PSO) technique has been used to tune the PID controller gains to get a snappier response. The results suggested that the IPMC actuator achieved the desired actuation response of 4 mm under the applied sinusoidal voltage. Also, it is concluded that the proposed experimental model can help researchers in getting proper actuation response from different RC characteristics of IPMC under electric potential in an underwater environment that can be used for application in the underwater biomimetic robotic devices.