Caterpillar-Inspired Insect-Scale Climbing Robot Using Dry Adhesives

Surface-to-surface transitions, vertical and inverted locomotion, and high payload capacity are important requirements for a climbing robot. Despite many previous approaches, the miniaturization of climbing robots that satisfy these requirements is still a big challenge. In this letter, we present an insect-scale wheeled climbing robot that employs a low-cost dry adhesive technology. The design, inspired by caterpillars, consists of 2 main links that are connected by a pivot joint. The prototype robot measures a length of 40 mm and a width of 10 mm, and it weighs 1.7 g. On a horizontal surface, the robot moves with a speed of 12.3 mm/s and can drag a load weight of 10 g (six times its weight) at a speed of 4 mm/s. The high torque-to-weight ratio achieved by two micro-geared ultrasonic motors permits vertical and inverted locomotion while carrying a high payload capacity (120% of the robot’s weight). The locomotion strategy for surface-to-surface transitions, i.e., movements at right angle corners, is substantiated by the functionality of the pivot joint. To satisfy the design requirements, many dry adhesive tapes are evaluated, and the climbing robot with an appropriate adhesion force is demonstrated.