Modified Nernst-Plank-Poisson Model for IPMC With Back-Relaxation Effects

Abstract

The ionic polymer–metal composite (IPMC) is a new practical engineering material that, it has a wide range of capabilities in both dry and liquid environments. IPMC is a new candidate for diaphragms in micropump devices, micro and Nano robotic applications. IPMCs are regarded as a capable actuator for transportable applications, however, the unique combination of electrochemical and mechanical properties that they possess, such as back-relaxation, restraint their use in real-life applications. There have a lot of attempts to understand and model the IPMCs properties and build a whole prototype that can be used, with certainty, in different robotic, control, and medical applications, yet, till now, it seems that the dehydration and back-relaxation are still not modeled properly. The Nernst-Plank-Poisson was chosen to be the base model for the IPMC behavior, we were able to create a new model that truly represent the back-relaxation effects that occur in IPMCs, we’ve called the new model as modified NPP model. The modification used captured data from our experimental work Our modified analytical NPP (Nernst-Plank-Poisson) model was the verified using MATLAB & Simulink, which showed that the model, and the controller design for it was able to first compensate the loss of position of the IPMC due to back-relaxation, and then track the desired position input signals with great accuracy. The model and designed controller can be utilized in verity of robotic applications.

Nafion-Pt IPMC electroactive behavior changes in response to environmental nonequilibrium conditions

“…This lead us to contemplate the immediacy and distance the IPMC back-relaxes away from this maximum while voltage is still applied (region iii). After δ max is reached, the solvent-controlled forces begin to dominate producing V on back relaxation [41,43,51,52]. The V on relaxation displacement witnessed was as follows: δ relax, 70% RH < δ relax, 85% RH < δ relax, DI liq < δ relax, 96% RH with the correlating values are 0.002, 0.041, 0.058, and 0.069 mm, respectively.…”

“…Secondly, this model does not specify the state of the water contained in the IPMC, and will be modeled using a 'hydration parameter' which, when adapted in this work, is representative of the amount and form of water. Lastly, Al-Allaq et al did not report the dimensions of their IPMC and ionic polymer core [43].…”

“…All work conducted in this publication was replicated for statistical certainty and quantitative deviation reporting. Lastly, experimental results were validated via fitting against an IPMC actuation model derived from literature, which included back-relaxation, electrical, mechanical, and hydration quality factors [43].…”

“…Maximum actuation displacement and bending actuation fitting derived by Al-Allaq et al are used to compare against the experimental findings of this work. This analytical model was selected based on its use of measurable and geometric parameters, with the inclusion of an IPMC's hydration properties, which make it so that experimental data can be directly implemented and compared [43]. The model fitting results are summarized in tables 3 and table 4.…”

PI Controller for IPMC Actuators Based on Nafion®/PT Using Machine Vision for Feedback Response at Different Relative Humidities

“…As shown previously, several papers have effectively controlled IPMCs using input/output controllers [42][43][44][45][46] . Many researchers have chosen a PI controller for its simplicity 55,[73][74][75] . Aw et al 76 designed a PI controller to monitor a robotic surgical instrument with one skeleton-joint mechanism actuated by IPMC.…”