Androids badly stand on the feet because of big weight. And from fall the massive machine can fail.
Robots of the Boston Dynamics company differ in stability, but they have four mechanical legs.
BALLU consists of two legs attached to a balloon. In mechanical foot placed all electronics and the accumulator. The collected design is a little heavier than air and at the expense of it is balanced. The robot remotely is operated.
The ball with legs moves in any party, jumps and climbs steps. BALLU can even go on water and fall from height. But ease of a design doesn’t allow to manage the robot in case of wind.