Modeling and open-loop control of IPMC actuators under changing ambient temperature

Abstract

Because of the cost and complexity associated with sensory feedback, open-loop control of ionic polymer-metal composite (IPMC) actuators is of interest in many biomedical and robotic applications. However, the performance of an open-loop controller is sensitive to the change in IPMC dynamics, which is influenced heavily by ambient environmental conditions including the temperature. In this paper we propose a novel approach to the modeling and open-loop control of temperature-dependent IPMC actuation dynamics. An IPMC actuator is modeled empirically with a transfer function, the zeros and poles of which are functions of the temperature. With auxiliary temperature measurement, open-loop control is realized by inverting the model at the current ambient temperature. We use a stable but noncausal algorithm to deal with non-minimum-phase zeros in the system that would prevent directly inverting the dynamics. Experimental results are presented to show the effectiveness of the proposed approach in open-loop tracking control of IPMC actuators.

Optimization of Ionic Polymer Metal Composite Fabrication via Chemical Electroless Plating Method; Actuation Application Study

“…Therefore, the IPMC actuator possesses both actuation figures of merit together; large deflection and low extinction voltage [6]. IPMCs have been used as actuators in different fields such as biomechanical and biomedical applications (artificial muscles and drug delivery systems) [7][8][9], robotics and MEMS (transducers and sensors) [10][11][12][13][14][15], as well as the aerospace and vehicles industry [16][17]. Using nafion-based IPMC in biomedical field is of concern due to biocompatibility of both nafion and IPMC [18][19][20][21].…”

Influence of temperature on the impedance of ionic polymer metal composites

“…While several studies have investigated the role of temperature on IPMCs [11][12][13][14][15][16], a systematic analysis of the effect of temperature on the impedance is currently lacking. For example, IPMC actuation at temperatures below zero degree celsius for cryogenic applications is demonstrated in [11].…”

“…Variations in the blocking force are further elucidated in [12]. In [13,14], the effect of temperature on IPMC sensing is studied, and a similar analysis on IPMC actuation is presented in [15]. To the best of our knowledge, the effect of temperature on IPMC impedance has only been considered in [16], where a resistor-capacitor model is utilized for interpreting experimental findings.…”

Force control of ionic polymer-metal composite actuators with carbon-based electrodes

“…Commonly, laser distance gauges [6,7] or force sensors [5] are employed. Alternatively, image processing has been used to capture the change in shape of an IPMC [8,9].…”