Electroadhesion (EA) provides electrically switchable adhesion and is a promising mechanism for perching micro aerial robots on smooth surfaces. However, practical implementations of soft and stretchable EA pads for aerial perching remain limited. This work presents (i) an efficient workflow for fabricating soft, stretchable electroadhesive pads with sinusoidal wave and concentric-circle electrodes in multiple sizes, (ii) a controlled experimental comparison of normal and shear adhesion under inactive (0 kV) and active (4.8 kV) conditions using an Instron-based setup, and (iii) a perching demonstration using a Crazyflie quadrotor equipped with electroadhesive feet on flat and curved substrates. Experimental results show that shear adhesion dominates, reaching forces on the order of 3 N with partial pad contact, while normal adhesion is comparatively small and strongly dependent on substrate properties. The Crazyflie prototype demonstrates repeatable attachment on smooth plastic surfaces, including curved geometries, as well as rapid detachment when the voltage is removed. These results highlight the potential of soft electroadhesive feet for lightweight and reliable perching in micro aerial vehicles (MAVs).
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Fig. 1: Crazyflie quadrotor equipped with soft electroadhesive pads demonstrating conformal attachment to a curved plastic surface.
Fig. 3: Working principle of the electroadhesive (EA) pad: (a) top view of the electrode layout and (b) cross-sectional view. The applied high voltage generates fringe electric fields that induce charge polarization on the substrate surface, resulting in electroadhesive forces.
Fig. 4: Fabrication process of the soft electroadhesive pad: (a) laser cutting of the conductive silicone electrode pattern; (b) casting of the laminated structure by placing the patterned electrode on the bottom Ecoflex layer, attaching the lead, and encapsulating it with a top Ecoflex layer.
Fig. 5: Six fabricated soft electroadhesive (EA) pads used for pad-level characterisation, including three wave-pattern designs (Wave 1–Wave 3) and three concentric-circular designs (Circle 1–Circle 3) with different electrode geometries and sizes.
Fig. 6: Experimental setups for pad-level characterisation: normal-force test and shear-force test using the Instron platform.
Fig. 7: Comparison of the average (a) normal force and (b) shear force generated by the six fabricated EA pads under 0 kV and 4.8 kV, respectively. Error bars indicate the standard deviation from repeated tests.
Fig. 8: System-level validation of the Crazyflie equipped with four soft electroadhesive feet based on the Circle 1 design. (a) Attachment on a flat plastic surface as the substrate was rotated from the horizontal to the vertical and fully inverted configurations. (b) Detachment sequence after the applied voltage was removed. (c) Attachment test on a flat wooden surface, showing weaker support and eventual detachment. (d) Attachment on a rolled plastic surface, including side views and a close-up showing conformal contact between the soft pads and the curved substrate. (e) Attachment test on a cylindrical PVC bottle, where vertical attachment was achieved but stable support in more demanding orientations was not maintained.
Aerial robotics studies the design, perception, control, and coordination of flying robots for navigation, inspection, transport, and physical interaction.
This paper investigates multi-material 3D printing as a method to fabricate non-planar structures with 3D-printed electrode patterns for electroadhesion. We printed flat electroadhesion pads as a planar benchmark and cylindrical pads as a non-planar demonstration, with conductive interdigitated electrodes 3D printed as part of the structure. Normal-force measurements showed voltage-controlled modulation in both geometries. At 3 kV, the flat pads generated approximately 0.11-0.13 N, while the cylindrical pads reached approximately 0.16 N at 5 N preload. These results demonstrate a step toward printed parts with built-in, electrically controlled adhesion and friction, beyond conventional planar electroadhesion pads.
Mostafa A. Atalla, Carol R. Derla, Pep Canyelles Pericàs +1
Robotics and Mechatronics Group, Faculty of EEMCS, University of Twente, 7522 Enschede, The Netherlands
To enable reliable climbing locomotion of quadruped robots on ferromagnetic surfaces, this paper presents a high-load-density electro-permanent magnetic foot with controllable adhesion, featuring force-feedback circular Halbach-net electro-permanent magnet (CHN-EPM) adhesion units and a magnetization control system. Due to its three-dimensional magnetic circuit structure and flux-concentration effect, the CHN-EPM enables a distributed parallel magnetic flux path with enhanced flux utilization, resulting in reduced sensitivity to air-gap variations and allowing effective adhesion to be maintained even under partial contact conditions. The proposed CHN-EPM generates a maximum adhesion force exceeding 1000 N with a load-to-weight ratio over 200:1. A magnetization driver and a two-stage pulse current control strategy are developed to regulate the excitation current amplitude and duration, enabling accurate and reliable magnetization. By incorporating a flexible pressure sensor for contact force feedback, the system can effectively monitor attachment and detachment states, ensuring robust adhesion switching under uncertain contact conditions. The proposed system is integrated into a commercial quadruped robot (Unitree GO2), demonstrating high-load adhesion on ceiling and vertical-wall surfaces and stable locomotion on painted, perforated, and curved ferromagnetic surfaces.
An Li, Bo Tao, I-Ming Chen +1
School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore · School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan430074, China
Electroaerodynamic propulsion is compelling for use in micro air vehicles due to its silent and solid-state nature, but its limited efficiency has thus far precluded a path towards power-autonomous flight. Recent work has shown that thrust density and efficiency for small-scale atmospheric ion thrusters can be vastly increased when operating close to a ground plane. Here, we explore the design space of centimeter-scale hovercraft, which can leverage this ground effect for low-altitude flight. We first perform an empirical investigation, characterizing the performance benefits and trade-offs for different geometries and configurations of passive hovercraft skirts, then use the results to fabricate a viable point design. We demonstrate a palm-sized hovercraft that, while tethered to an external power source, can fly for extended periods, withstand dozens of takeoff and landing cycles, passively stabilize to reject significant mechanical disturbances, and generate practically zero audible noise signature. The measured thrust efficiency of 16 mN/W and additional payload capacity of almost 1.5 grams above the vehicle's self mass of about 1.6 grams exceeds any similarly sized electroaerodynamically propelled robot by an order of magnitude. This is the first time an ion-propelled micro hovercraft has been shown in the open literature, and our work points the way towards an entirely new class of robot.
C. Luke Nelson, Grant Nations, Mrinmoy Modak +1
C. Luke Nelson1, Grant Nations1, Mrinmoy Modak2, and Daniel S. Drew2