Here is a microrobot that can climb vertical, inverted, and curved surfaces. HAMR-E was developed by researchers at the Wyss Institute & Harvard SEAS. It measures 4.5cm long, weighing 1.48g. Its electroadhesive pads, origami ankles, and tripedal crawl gait enable the robot to climb conductive surfaces of any orientation.
HAMR-E can be used to explore spaces too small for humans. It could one day be used to inspect jet engines.