Hybrid soft-rigid foot with dry adhesive material designed for a gecko-inspired climbing robot

Mini Review: Comparison of Bio-Inspired Adhesive Feet of Climbing Robots on Smooth Vertical Surfaces

“…They require only shear force to attach to surfaces [ Hawkes et al (2015) ]. By contrast, mushroom-shaped feet require a slight initial normal force to attach to surfaces [ Kim et al (2008) ; Shao et al (2020) ]. The detachment mechanism of the spatula-shaped microstructure is also straightforward.…”

“…These surfaces determine the adhesion technologies for the feet, such as magnetic adhesion on ferromagnetic surfaces, mechanical gripping on trees/pipes, and suction/dry adhesion on glass [ Chattopadhyay and Ghoshal (2018) ]. Spatula-shaped and mushroom-shaped feet are most commonly used in climbing robots, e.g., StickyBot [ Santos et al (2008) ], StickyBot I; [ Kim et al (2008) ], StickyBot III [ Hawkes et al (2011) ], Geckobot [ Unver et al (2005) ], Gecko-Inspired Soft Robot [ Schiller et al (2019) ], Abigaille I [ Menon et al (2008) ], Abigaille II [ Li et al (2012) ], Tailless Gecko Robot [ Srisuchinnawong et al (2019) ], 9 g climber [ Hawkes et al (2015) ], Mini-WhegsTM7 [ Daltorio et al (2006) ], Waalbot II [ Murphy et al (2011) ], Wall and Ceiling Climbing Quadruped Robot [ Ko et al (2017) ], and Gecko-Inspired Climbing Robot [ Shao et al (2020) ]. Thus, this review mainly focuses on bio-inspired adhesive feet for smooth vertical surfaces such as glass.…”

“…The adhesive covers almost half of the contact area of the material [ Gorb S. et al (2007) ; Figure 2B ]. The MSAMS makes contact with the preload along the normal force axis and can be detached by the peeling technique at some angles [ Shao et al (2020) ]. The adhesion of MSAMS has approximately twice the pull-off force of surface without MSAMS (flat surface) made from the same material, while both were independent of the preload.…”

Bioinspired Smart Materials With Externally-Stimulated Switchable Adhesion

“…However, using a fully soft material is unable to apply sufficient pressure to the whole foot. In order to enhance payload capacity and achieve effective climbing behaviors, Shao et al (2020) combined hard aluminum alloy, soft polydimethylsiloxane (PDMS) and biologically inspired dry adhesive materials to propose a gecko-inspired foot design with a hybrid sandwich structure. Owing to the novel structure with an approximate area of 12.56 cm 2 , two feet can carry a weight of 3.2 kg.…”

Editorial: Biology-Inspired Engineering and Engineering-Inspired Biology

“…The term biology-inspired engineering refers to the fact that biology has been an important inspiration for developments in all aspects of engineering, for example the design of robots. Bio-inspired computation (Manoonpong and Tetzlaff, 2018;Manoonpong et al, 2020), sensors (Steffen et al), actuators (Vanderborght et al, 2013;Dicker et al, 2017;Lee and Oh, 2019;Lund et al, 2019), structures (Tramsen et al, 2018;Tan et al, 2019;Shao et al, 2020), and materials (Rafsanjani et al, 2018;Wang et al, 2020) have enabled robots to produce robust and comparable behaviors to their biological counterparts. Owing to the biologically comparable behaviors, interdisciplinary biologists tend to flip the approach, i.e., engineering-inspired biology, whereby engineering systems and principles are utilized to initiate and test new hypotheses in biological research.…”