Triboelectric-Based Film-Type Soft Robot Driven via Low-Frequency Mechanical Stimuli

Triboelectric nanogenerators (TENGs) have received considerable attention owing to their ability to harvest energy from the environment. They can be effectively used as a self-generating power source to drive low-power devices. Compared with other energy harvesting technologies, the energy conversion efficiency is much higher, but the current output is low—only enough to drive an existing rotor-type motor. In this study, we designed a film-type soft robot that can produce high-voltage, low-power, triboelectric output without using a motor. Polyvinylidene fluoride (PVDF) film was used as the actuator for the soft robot. We designed a resonance structure to increase the movement of the soft robot driven by low-frequency triboelectric output. A driving test was performed by simulating the shape of butterfly wings and an inch-worm. When the butterfly-shaped PVDF film robot simulated the flapping motion of wings using the resonance structure parameter design, it was able to generate 2.5 times greater movement than the model without the resonance structure. In addition, the artificial inch-worm soft robot optimized for the TENG input was fabricated by applying the parameter design method to the PVDF film. We developed and tested a self-powered, intelligent soft robot that can be driven by low-frequency mechanical stimuli. This study can help extend the application of triboelectric generators.