Building a biped: Another year, another robot

With the experience of the first robot I knew that the
most important thing was to make the robot light and strong
enough to allow it to stand on one leg.

The first robot (model 1) had six degrees of freedom in each
leg. I decided that I could do with four.

The new model used power functions motors combined with
RCX rotation sensors. The robot was controlled with three
NXT bricks which was not enough to control all functions
but it did allow me to experiment with the legs.

The primary goal, building a robot which could stand on
one leg was achieved.

Unfortunately by solving one problem I ran into another
problem. When you control a motor you have to know the
exact angle of the axis. To do this you have to put
the robot in a starting position of which all angles
are known. From there you can move the axis relative to
the start position.



Next time: Fixing the reset and control issues...

Here´s something fantastic...
Stuff like this used to be science fiction:

Trying to build a biped robot

Last week Chris invited me to contribute to Tinkernology,
and here it is... your reading my first post.

Every year I build one large LEGO model. My last model
which wasn't a robot was a Startrek model. (if you're
interested you can find it here)

About four years ago I started looking for a new building
challenge. It had to be something technical, with lots
of electric components.

What could be considered almost impossible to build?
I decided to build a biped robot...

The first goal was to just try and see how far
I would come. After studying videos and images of Hondas
Asimo robot I started building.

I used the old 9v motors combined with the RCX
rotation sensors. After working on the robot for about six
months it was finished, it had 22 degrees of freedom.

When the robot was finished it was clear that my construction
would not be able to walk. The legs could move but the robot
was too heavy to stand on one leg.

Another problem was the complexity of controlling the robot.
Because of the large number of motors and sensors I needed
eight RCX bricks to control it. It was just not practical.



So... the robot was finished, was looking pretty good but
could not walk. What should I do now, look for something
else to build? Or would it be possible to improve my design?

Next time: Another year, another robot...

The masters showing how it's done: