Mechanical Work and Electromechanical Coupling in Ionic Polymer Bender Actuators
Abstract This paper presents a coupled, electromechanical model of a Nafion-based ionic polymer transducer used in the cantilevered bender configuration. A comparison of simulated and experimental responses for a 0.2mm × 5.0mm × 17mm actuator validates both the form of the model and the empirically determined model parameters. In one of the experiments used for parameter identification, the short circuit current is found to be proportional to the induced actuator velocity, with the constant of proportionality equal to 7.5E−04 A m / s . This model differs from those presented by other researchers in that it is simple, dynamic, and is able to represent the transducer as either a sensor or as an actuator. Also presented is an assessment of the polymer actuators’ ability to perform mechanical work. The results of a series of force versus deflection experiments are outlined, and energy densities are calculated to facilitate comparison with other actuator technologies. The maximum blocked force with a 1.25V step input was 1.6mN (with a 17mm actuator), and the maximum free deflection with a 1.25V step input was 1.8mm (with a 22mm actuator). The energy densities ranged from 1.1 to 12.8 mJ/kg and 3.4E−06 to 4.0E−05 mJ/mm3 with an input range of 0.75V to 1.25V.