  Multimodal locomotion capability is an emerging topic in robotics field, and
various novel mobile robots have been developed to enable the maneuvering in
both terrestrial and aerial domains. Among these hybrid robots, several
state-of-the-art bipedal \robots enable the complex walking motion which is
interlaced with flying. These robots are also desired to have the manipulation
ability; however, it is difficult for the current forms to keep stability with
the joint motion in midair due to the central\ized rotor arrangement.
Therefore, in this work, we develop a novel air-ground amphibious quadruped
robot called SPIDAR which is assisted by spherically vectorable rotors
distributed in each link to enable both walking motion and transformable
flight. F\irst, we present a unique mechanical design for quadruped robot that
enables terrestrial and aerial locomotion. We then reveal the modeling method
for this hybrid robot platform, and further develop an integrated control
strategy for both walking and fl\ying with joint motion. Finally, we
demonstrate the feasibility of the proposed hybrid quadruped robot by
performing a seamless motion that involves static walking and subsequent
flight. To the best of our knowledge, this work is the first to achieve a
\quadruped robot with multimodal locomotion capability, which also shows the
potential of manipulation in multiple domains.
