LEONARDO Robot Has Legs And Thrusters, Can Skateboard, Slackline
Caltech's LEONARDO robot (that's LEgs ONboARD drOne, if you're keeping track of complex acronyms) is a multi-modal, bipedal robot using both legs and torso-mounted thrusters.
This allows some very fancy movements.
Creatures that have more than two locomotion modes must learn and master how to properly switch between them. Birds, for instance, undergo a complex yet intriguing behavior at the transitional interface of their two locomotion modes of flying and walking.
Similarly, the Leonardo robot uses synchronized control of distributed propeller-based thrusters and leg joints to realize smooth transitions between its flying and walking modes. In particular, the LEO robot follows a smooth flying trajectory up to the landing point prior to landing. The forward landing velocity is then matched to the chosen walking speed, and the walking phase is triggered when one foot touches the ground.
After the touchdown, the robot continues to walk by tracking its walking trajectory. A state machine is run on-board LEO to allow for these smooth transitions, which are detected using contact sensors embedded in the foot.
I'm pretty sure that Thomas Edison had something similar in mind when he worked with George Parsons Lathrop on In the Deep of Time, published in 1897. He describes a "walking balloon":
...they were in Wisconsin, and stepped off into a "walking balloon", which proceeded with long strides of its aluminum legs over a slant of steep upland.
This vehicle is a shallow car with small hollow sails of silk above it, containing just enough gas to keep it about thirty feet above ground, assisted
by a small electric engine in the centre. From the bottom of the car two long
rods or mechanical legs, made of aluminum—the lightest metal known—
extended down to the ground, where they are reciprocated at regular
intervals by an electrometer, which enables them to imitate the motion of
walking, and carry the balloon along at the rate of some fifteen miles an
hour. They are not meant for high speed, and can travel only, of course, on
prepared routes, but are very convenient in certain places.