assembling and self-reconfiguring

robot systems. These are modular

robots with the ability of

changing their geometry according

to a task. And this is exciting

because a robot designed for a

single task has a fixed

architecture and that robot will

perform the single task well but

it will perform poorly on a

different task in a different

environment. If we do not know

ahead of time what the robot

will have to do and when it will

have to to it, it is better to

consider making modular robots

that can attain whatever shape

that is needed for the manip-

ulation, navigation or sensing

needs of the task. Up until now

most other modular robotic

systems use servos and motors

in order to have arms that and

attachments that move modules to

different places. However we

wanted a simpler approach that

uses fewer actuators, fewer

moving parts and was easier to

implement on a lot of different

robots. So the approach we chose

to use is angular momentum.

And essentially what that means

is there is a spinning mass that

spins inside the robot. If we

want that robot to move it stops

that spinning mass which takes

that motion from the mass and

applies it to the robot. And the

part of this that is unique is

that the spinning mass is

completely inside the robot and

so the robot doesn't have to be

in a certain position in order

for the force to be acted upon

the robot so this allows for

a lot more types of motion with

only one actuator.

So there were a couple challenges

when we came to design the

m-blocks, one, was fitting

everything inside. So we have a

relative small volume and we

needed to fit a brushless motor

controller, a flywheel, a

breaking mechanism, electronics

a radio and a battery.

Additionally we faced the

challenge of trying to simplify

and try and make the design as

robust as possible. So we didn't

want any external moving parts.

We didn't want latches, we

didn't want the cubes to change

their shape. We just wanted

simple blocks that were able to

move on their own. The magnet

system in the cubes is one of

its key features. We have face

magnets. There's eight face

magnets that provide some course

alignment and then there are

these edge magnets which are

free to rotate. And the key is

that when a cube starts rotating

the edge magnets actually get

close to one another. So if we

start from this configuration and

we break the face magnets free

and start rotating the edge

magnets actually get a little

bit closer due the fact that the

edge is slightly cut back and as

a result you form a very strong

bond between cubes which allows

them to stay attached as one is

rotating into a new position. It

continues rotating, the face

magnets provide alignment and

it snaps into place.

One other benefit of having an

internal actuator is that the

cubes are able to jump

and this is a capability that

very few robots have. Especially

very few modular robots because

in order to jump there's a

requirement for a very high

amount of energy in a very short

amount of time and most robots

are optimized for control,

stability and precise motion.

In our robot we found it kind of

as an accident that they are

able to jump, we weren't

intending to do that but it ends

up that we need enough momentum

inside each cube in order to

move on a lattice structure,

which is what we intended, that

we can also, when we apply as

much energy as possible, it can

jump through the air which is

pretty exciting because it also

allows robots to jump on top

of each other and go places that

they couldn't go if they were

only moving directly on the

structure. Currently we're

sending commands to the modules

with a radio. So we type commands

on our computer, those are

transferred over a wireless link

like your wifi system in your

house, and then the cube responds

to that. In the future we

envision putting the algorithms

on the modules themselves so

they can completely, autonomously

in a distributive fashion decide

how, when and where to move. So

we want to be able to take a

large group of cubes and tell

them form this shape, and give

those instructions at a very high

level and then have the cubes

decide, on their own, how to go

about accomplishing that task.