Monolithic Piezoelectric Insect With Resonance Walking

This paper describes the design, manufacture, and performance of an untethered hexapod robot titled MinRAR V2. This robot utilizes a monolithic piezoelectric element machined to allow for individual activation of bending actuators. The legs were designed so that the first two resonance modes overlap and therefore produce a walking motion at resonance. The monolithic construction significantly improves the matching of resonance modes between legs when compared with previous designs. Miniature control and high-voltage driving electronics were designed to drive 24 separate piezoelectric elements powered from a single 3.7 V lithium polymer battery. The robot was driven both tethered and untethered, and was able to achieve a maximum forward velocity of 98 mm/s when driven at 190 Hz and 6 mm/s at 5 Hz untethered. The robot is capable of a wide range of movements including banking, on the spot turning, and reverse motion.