Let's tell the quad to come back here and let the pole drop, and I will next demonstrate the importance of understanding physical models and the workings of the physical world.

Take this quad, for example.

Quads have been around for a long time.

Quads are extremely agile, but this agility comes at a cost.

We then next calculate how the quad should hit the ball so that it flies to where it was thrown from.

For example, that's how we can make the quad hover.

We will demonstrate the concept of machine athleticism and the research to achieve it with the help of these flying machines called quadrocopters, or quads, for short.

Here, the quad is behaving as if it were in a viscous fluid.

Once we have a model of the combined quad pole system, we can use control theory to create algorithms for controlling it.

The air assets fleet consists of 1 fixed wing and 13 rotary wing aircraft for the period 1 July to 31 December 2005 and of 1 fixed wing and 2 rotary wing aircraft for the period 1 January to 30 June 2006, compared to 1 fixed wing and 28 rotary wing aircraft for the full 12 month period in 2004 05.

These three quads are cooperatively carrying a sky net.

We added the mathematical model of the pole to that of the quad.

It naturally doesn't spill, no matter what the quad does.

I did not include the mathematical model of the glass in the system.

The estimates for air transportation included operating costs, liability insurance and fuel for a fleet of 12 fixed wing and 11 rotary wing aircraft for the first period and, under the revised deployment schedule, of 18 fixed wing and 37 rotary wing aircraft for the second.

Let me introduce you to the wizards behind the green curtain.

This is auto gyro jousting in Malibu in the 30s.

Like before, I could use the pointer to tell the quad where I want it to be in space.

We now have a natural way of interacting with the raw athleticism of these quads with my gestures.

The spare parts included helicopter rotors, tail sections, engines, cockpits and other sundry parts for four Kanov 26 helicopters.

Suppose that we want this quad to not only hover but to also balance this pole.

You can notice that this quad is making fine adjustments to keep the pole balanced.

We can also augment the model to include where we want the quad to be in space.

Notice how the quad lost altitude when I put this glass of water on it.

Third, a trajectory is planned that carries the quad from its current state to the impact point with the ball.

We can use mathematical models to estimate the force that I'm applying to the quad.

Twenty milliseconds later, the whole process is repeated until the quad strikes the ball.

Notice that, at full extension, these quads are vertical.

For what you will see next, these quads will initially behave as if they were on Pluto.

Others think that it has more of a social role, that it's used to bind the group.

Once we know this force, we can also change the laws of physics, as far as the quad is concerned, of course.

I can point to where I want the quad to be in space a fixed distance away from me.

We then manipulate these equations with the help of control theory to create algorithms that stabilize the quad.

Suppose we want this quad here to perform a triple flip and finish off at the exact same spot that it started.

The algorithms to do this are very similar to what the single quad used to hit the ball back to me.

In this instance, carrying a glass of water is easy.

As a youngster, I was very interested in model airplanes, ornithopters, autogyros, helicopters, gliders, power planes, indoor models, outdoor models, everything, which I just thought was a lot of fun, and wondered why most other people didn't share my same enthusiasm with them.

So we can physically interact with these quads and we can change the laws of physics.

This quad has a racket strapped onto its head with a sweet spot roughly the size of an apple, so not too large.

I will use this new capability to position this camera carrying quad to the appropriate location for filming the remainder of this demonstration.

The auto gyro couldn't wait for the invention of the helicopter, but it should have it wasn't a big success.

We then use a branch of mathematics called control theory to analyze these models and also to synthesize algorithms for controlling them.

With a little bit of practice, it's pretty straightforward for a human being to do this, although we do have the advantage of having two feet on the ground and the use of our very versatile hands.

You put these two things together, the net result is that all side forces on the glass are small and are mainly dominated by aerodynamic effects, which at these speeds are negligible.

You're all thinking now, these guys are having way too much fun, and you're probably also asking yourself, why exactly are they building machine athletes?