High-Force Electroadhesion Based on Unique Liquid-Solid Dielectrics for UAV Perching

Electroadhesion (EA), as an electrostatically driven, controllable adhesion technology, has unique attributes such as low noise, robust adaptability, and energy efficiency. However, its adhesion pressure is still low (0.1~10kPa) which may significantly limit its applications. This paper presents an innovative electroadhesion pad embedded with liquid and solid dielectrics. The experiments demonstrate that this liquid-solid electroadhesion pad (LSEAP) is capable of much larger adhesion pressure, compared to the traditional solid electroadhesion pad (SEAP). On one hand, the LSEAP can increase the dielectric contact with the substrate. On the other hand, the actuator can increase its dielectric strength. We also explore the application of this actuator to perching of a commercial Unmanned Aerial Vehicle (UAV), in order to promote the UAV's sustainable flight. Notably, the untethered LSEAP system, with an adhesion area as small as 4 cm² and a self-weight as light as 8.7 g, can support an UAV of 249.7 g for stable adhesion on various surfaces. The adhesion pressure generated by our LSEAD can be 32.2kPa, significantly larger than those reported in the literature. The weight ratio of the UAV to the LSEAP system is 14.6, more than double those in previous studies. The integration of this EA system markedly prolongs the operational duration of UAVs, rendering them suitable for sustainable surveillance and reconnaissance missions. This LSEAP also marks a pivotal advancement towards adhesion-based applications such as grippers and wall-climbing robots.