IPMC Actuator for Swimming Microrobots

IPMC Actuator for Swimming Microrobots

Boerefijn, Leroy (TU Delft Mechanical, Maritime and Materials Engineering)

Hossein Nia Kani, Hassan (mentor)

Delft University of Technology

2017-08-21

Autonomous microrobots ‘swimming’ through bodily fluids promise a major breakthrough in the fields of medicine and surgery. Targeted drug delivery, ablations, stents, implants, and remote sensing applications are among the envisioned applications. One of the biggest challenges in the design of these devices is the propulsion actuator. Within this thesis, Ionic Polymer Metal Composite (IPMC) is proposed for the design of a distributed actuator. This smart material consists of a polymer backbone that is permeable to cations, whilst being impermeable to anions. When an electric potential is applied over the thin platinum electrodes, the cations migrate towards the negative electrode, while the anions remain fixed. This results in an expansion near the negative electrode, due to the higher concentration. Simultaneously, the material contracts at the positive electrode. On the macro level, this results in a large bending deformation of
the IPMC strip. Using an improved video processing algorithm, the curvature of a strip of IPMC is investigated. By analyzing the dynamic response in fluids of varying viscosity, it is shown that IPMC behaves well in low-Reynolds environments. Thereby, IPMC is shown to be a feasible actuator at microscale, where viscous forces dominate inertial forces. Next, a novel swelling based model in Comsol is proposed. Since it accurately shows the deformation shape, is easily adaptable, and has fast computation times, it is highly suitable for engineering purposes. Finally, a methodology is proposed for designing IPMC based bending tail actuators. Segmented IPMC is kinematically modeled with a constant curvature assumption. Using a nested optimization algorithm, the segmentation is designed for optimally attaining a desired wave shape. The traveling wave behavior is confirmed through the Comsol model. Hopefully, this work provides a basis for future work to build on, thereby giving new direction to the development of microrobots for medical purposes.

IPMC
curvature
camera
viscosity
Comsol
hygroscopic swelling
segmented IPMC
beating tail
swimming microrobots
kinematic modeling

http://resolver.tudelft.nl/uuid:c46870ea-b4dd-4488-bb5d-6d6819f1c543

Student theses

master thesis

© 2017 Leroy Boerefijn