  Aerial robots the size of a honeybee (~100 mg) have advantages over larger
robots because of their small size, low mass and low materials cost. Previous
iterations have demonstrated controlled flight but were difficult to fabricate
because they consisted of many separate parts assembled together. They also
were unable to perform locomotion modes besides flight. This paper presents a
new design of a 74 mg flapping-wing robot that dramatically reduces the number
of parts and simplifies fabrication. It also has a lower center of mass, which
allows the robot to additionally land without the need for long legs, even in
case of unstable flight. Furthermore, we show that the new design allows for
wing-driven ground and air-water interfacial locomotion, improving the
versatility of the robot. Forward thrust is generated by increasing the speed
of downstroke relative to the upstroke of the flapping wings. This also allows
for steering. The ability to land and subsequently move along the ground allows
the robot to negotiate extremely confined spaces, underneath obstacles, and to
precise locations. We describe the new design in detail and present results
demonstrating these capabilities, as well as hovering flight and controlled
landing.
