This paper presents analysis and results for a small and agile wall climbing robot's ability to regain lost adhesion due to degradation of dry fibrillar adhesives. To regain the lost adhesion, two feet are set to the surface and the robot performs a rocking motion on the side where the adhesion has dropped below a safety threshold. The rocking motion applies normal forces to preload the front and rear feet without letting the other foot detach from the surface by alternating the direction of the motor and only allowing small rotation of the leg. Experimental results show that the rocking motion is successful in regaining lost adhesion while using dry fibrillar adhesives on a smooth, vertical acrylic surface. The performance of the fibers over time limits the adhesion that can possibly be mechanically regained and as a result the fibers are over-designed, which gives rise to the need for a power efficient peeling mechanism. The peeling mechanism uses a conditionally locked ankle, implemented with magnets, and a slot to allow the axle to change a pulling force normal to the surface to be a pulling force perpendicular to the surface, which peels the fibers using the uneven loading. Experimental results illustrate that a passive peeling mechanism is successful in reducing the required power to peel. The presented advancements can be applied to other climbing robots using adhesives to allow for safer, more efficient climbing.

This video presents a palm-size climbing robot which uses synthetic fibrillar dry adhesives inspired by geckos. With fibrillar footpads, the robot is shown to climb smooth surfaces such as glass and acrylic, and surfaces with micron-scale roughness such as wood. In particular, the agility of the robot is highlighted by demonstrations of climbing, steering, and plane-to-plane transitions.

This paper presents the fabrication, characterization and testing of bio-inspired synthetic dry adhesive fiber arrays. Fibers were fabricated via micromolding followed by spatula tip formation via dipping. Arrays of fibers with diameters between 28 mum and 57 mum and a height of 114 mum were fabricated with high uniformity on 6.25 cm2areas with up to 95% yield. Adaptation to uneven surfaces was observed with fiber elongations over 6 times the original height of the fiber. The unstructured sample exhibited 1.6 times as much adhesion as the fiber array sample for the flat punch indenter. However, fibrillar samples demonstrated up to 5.3 times as much adhesion as the unstructured sample for the hemispherical indenter. The fibrillar adhesive sample was implemented on a wall climbing robot which was able to carry itself and climb a distance on a painted wall and wood door.

This paper proposes a small-scale agile wall climbing robot able to navigate on smooth surfaces of any orientation, including vertical and inverted surfaces, which uses adhesive elastomer materials for attachment. Using two actuated legs with rotary motion and two passive revolute joints at each foot the robot can climb and steer in any orientation. Due to its compact design, a high degree of miniaturization is possible. It has onboard power, sensing, computing, and wireless communication which allow for semi-autonomous operation. Various aspects of a functioning prototype design and performance are discussed in detail, including leg and feet design and gait control. The current prototype can climb 90deg slopes at a speed of 6 cm/s and steer to any angle. This robot is intended for inspection and surveillance applications and, ultimately, space missions