Two-legged drone: the tightrope walker among robots

For “Leonardo” there doesn't seem to be any obstacles, however high or low they may be.

The robot overcomes stairs or walls with ease by simply swinging itself into the air.

He can easily manage uneven terrain on foot.

The machine being around 75 centimeters tall and 2.5 kilograms can also dance on the rope without falling, and even on a skateboard it can master a slalom course without falling.

Leonardo, known as Leo for short, does not seem to be able to upset the balance.

Even if it is kicked by a stick or a strong wind blows from the side, it will maintain its direction of travel.

Manfred Lindinger

Editor in the “Nature and Science” section.

• Follow I follow

Leo is the first two-legged robot that can also fly. This makes it extremely flexible and can do things that other robots are not allowed to do. The machine, whose name is an acronym for “LEgs ONboARD DrOne”, was developed by scientists led by Soon-Jo Chung from the California Institute of Technology (Caltech) in Pasadena. As the researchers

write

in the current issue of

, Leo closes the gap between bipedal and flying modes of locomotion - two types of movement that are not yet linked in the robots available on the market. This makes Leo a drone and walking robot at the same time.

Four movable propellers are located on Leo's shoulders.

Two each face forwards and backwards.

The rotors give buoyancy and protect the robot from a dangerous tilt and fall when it is on foot in difficult terrain.

If the thrust is big enough, Leonardo takes off and flies over the obstacle.

When designing the robot, the researchers used birds as a model.

The animals, which are both hopping and flying, keep their balance by flapping their wings, for example when they land on a power line or a thin branch.

Leonardo can move around autonomously with the help of the on-board computer and various sensors.

A navigation system helps him find his way around.

He captures the surroundings with a camera.

Lightweight construction

So that Leonardo can take off into the air as easily as possible, the robot pushes itself off with its feet when it starts.

Sensors are also located there.

These also register as soon as the robot has secure ground under its feet again.

The system then switches to a two-legged gait and adapts the rotor output accordingly to the new condition.

While Leonardo can move elegantly through the air, his running style seems rather lanky.

With a speed of 20 centimeters per second, it is not one of the fastest walking robots.

Each leg is moved by three servo motors - one motor sits on the pelvis, two motors are on Leonardo's hip.

When running, only the tips of your feet touch the ground.

They are covered with non-slip rubber.

In peace, Leonardo also stands on his heels.

The four propellers are constantly in operation. If one were to optimize the gait and make the feet and legs, which are made of carbon fibers, more stable, the rotors could largely be dispensed with, according to the researchers. But Leonardo's ongoing locomotion is of minor importance anyway. Chung and his colleagues see the areas of application of Leonardo wherever it is dangerous for people and the terrain is unsuitable for ordinary walking robots - it would be ideal for inspecting high-voltage lines, for example. Leo could land on the lines and possibly make repairs there as well.

In the next step, the researchers working with Chung Leonardo want to equip them with artificial intelligence.

This should give the robot a certain sense of the body and be able to independently decide how much the propellers need to support it when walking.