Abstract
In recent years, dielectric elastomer actuators (DEAs) have attracted lots of attention for providing multiple degree-of-freedom motions, such as axial extensions, torsion, bending, and their combinations. The wide applications include soft robots, artificial muscles, and biomimetic animals. In general, DEAs are composed of stretchable elastomers sandwiched by two compliant electrodes and actuated by applying external electric stimuli. Since most DEAs are limited by the breakdown thresholds and low strain-to-volume ratios, dielectric fluid transducers (DFTs) have been developed by substituting dielectric elastomers with dielectric fluids for high breakdown threshold voltages. In addition, DFTs have large rate of lateral extensions, due to their fluid contents, and are beneficial for soft actuators and pumping applications. In this research, we exploited DFTs to develop a soft spiral proboscis actuator inspired by the proboscises of butterflies for achieving uncoiling and coiling motions under external voltages. The bio-inspired spiral proboscis actuator (BSPA) was composed of a coil-shaped tube, a DFT-based pouch, and a spiral spring for mimicking the tubular part, a mechanism to uncoil the tube, and a mechanism to coil the tube, respectively. When applying external voltages to the pouch, the high dielectric fluid was injected into the empty coiled tube for uncoiling where the tube elongated from a compact volume to a stiff and flexible shape. When removing the exciting voltages, the tube retracted to its original coiled shape via the elastic spring. A prototype was designed, fabricated, and examined with high stimulating voltages. It was demonstrated that the proboscis actuator could achieve uncoiling and coiling motions consistently for several cycles. Compared to convection DEA-based pumps with fixed shapes, the proposed actuator is soft and beneficial for portable applications and coiling/uncoiling motions.
Highlights
With retrospect to evolution through billions of years, nature tends to develop soft and versatile actuators which give creatures more capability to survive and adapt to the dynamic and tough environment
We present the working principle of bio-inspired spiral proboscis actuator (BSPA) based on dielectric fluid transducers (DFTs) and applied external voltages
Based on empirical experiments and trial-and-error tests, we discovered that the breakdown voltage of our setup was approximately 14.5 kV
Summary
With retrospect to evolution through billions of years, nature tends to develop soft and versatile actuators which give creatures more capability to survive and adapt to the dynamic and tough environment. Compared to rotor-based machinery and hard metal components, soft actuators tend to be more tolerant and versatile. In these actuators, numerous motions are achieved according to osmotic pressure, including cnidocytes in cnidarians, capture motions done by carnivorous plants, and guard cells in plants [1]. Soft actuators possess many unique advantages that common mechanical actuators are not able to achieve These features are extensible, shock-absorbing, lightweight, inexpensive, and highly compliant to the environment. The soft actuator normally performs three kinds of actuating motions, uniaxial stretching [2], bending [3,4], and torsion [5,6,7].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
