Gold/Polypyrrole (Au/PPy) Bimorph Actuator for Underwater Robotic Motion

Recent developments in smart materials gained attention for developing underwater micro robots for various applications like scanning, surveillance and defense. Polypyrrole, ionic electro-active polymer (EAP) actuators has shown its effectiveness in miniaturized bio-inspired robots because of its incompetent characteristics like light weight, flexibility, large strain and bending deformation with low input voltage, high work density and natural muscle like behavior and performances. However, low operational life and bending displacement limits its underwater application, in this paper, we have fabricated a low cost PPy bimorph actuator and demonstrated its underwater performances and application by developing a PPy actuator based tadpole robot. The actuator is fabricated by using multi-layer electrochemical polymerization and performance evaluation by underwater bending experiment followed by the prototype development and operations. The actuator tip displacement, force and generated thrust are evaluated from the bending of actuator in quiescent water. It has been seen that the actuator can bend upto 5.4mm with 4.2mN of tip force upon applying a low voltage of nearly 1.3V. Further the response of the actuator is significantly fast and can continuously work upto 12 hrs without reporting any significant failure. Then the prototype is developed similar to natural tadpole by considering its morphological parameters and conduct further experiment for its swimming capabilities in terms of thrust, speed and efficiency. The performance parameters of the current robot are compared with the natural tadpole and existing models for validation of the present model. It can be believes that the present actuator can be used for real time underwater robotics applications like scanning and surveillance.