Screenbot: Walking inverted using distributed inward gripping

Abstract

Insights from biology have helped reduce the weight and increase the climbing ability of mobile robots. This paper presents Screenbot, see Fig. 1, a new 126 gram biologically-inspired robot that scales wire mesh substrates using spines. Like insects, it walks with an alternating tripod gait and maintains tension in opposing legs to keep the feet attached to the substrate. A single motor drives all six legs. Mechanisms were designed and tested to move the spines into and out of contact with the screen. After the spine engages the substrate, springs along the leg are compressed. The opposing lateral spring forces constitute a distributed inward grip that is similar to forces measured on climbing insects and geckos. The distributed inward gripping (DIG) holds the robot on the screen, allowing it to climb vertically, walk inverted on a screen ceiling and cling passively in these orientations.