Raffaello D'Andrea received the B.A.Sc. degree in engineering science from the University of Toronto in 1991, and the M.S. and Ph.D. degrees in electrical engineering from the California Institute of Technology in 1992 and 1997. Since then, he has been with the Department of Mechanical and Aerospace Engineering at Cornell University, where he is an Associate Professor.

His research interests include the development and application of algorithms for controlling complex systems, such as autonomous and semi-autonomous vehicle systems, and systems with thousands of actuators and sensors. More details may be found at www.mae.cornell.edu/raff

Dr. D'Andrea has been the recipient of a Natural Sciences and Engineering Research Council of Canada Centennial Graduate Fellowship (1991-1996), the American Control Council O. Hugo Schuck Best Paper award (1994), the IEEE Conference on Decision and Control Best Student Paper award (1996), a National Science Foundation Career Award (2000), a Presidential Early Career Award for Scientists and Engineers (2002), and several departmental and college wide teaching awards at Cornell University.

He is also the system architect and faculty advisor for the two-time world champion Cornell RoboCup team.

Tom asks:
How could I start building robots and what kind of education do I need to start doing it?

D'Andrea's response:
You can actually start building robots right away. If you have absolutely no previous experience, the best place to start is with "out of the box, ready to go" kits such as Lego Mindstorms. These kits will allow you to get an appreciation for simple automation and locomotion, and basic programming. Another way to go is with "build your own" robot kits; an excellent link is http://www.robotbooks.com/.

If you want to REALLY build your own robots, there are three basic skills required: electronics, mechanical design, and computer programming. Let's start with the last skill, because it is probably the one that is most easily obtained. Most robots need some type of intelligence; this is typically implemented via a computer program implemented on a micro-controller (a close cousin of the microprocessor, such as the Pentium family of microprocessors). In order to program a micro-controller, you will need to know how to write programs in languages such as C or C++; in fact, any programming language should suffice as a starting point -- for me it was the BASIC programming language, followed by assembly language on the Z80 micro-processor when I was eleven. If you have a home computer, you can learn how to write programs!

Skill in mechanical design can best be obtained by beginners through hands-on experience. If you know someone with machining skills, ask them if you can help them with their next project, and very quickly you will be able to build your own creations! Make sure that you augment this hands-on experience with reading material; for example, a quick search on the web under "gear design" yielded http://www.howstuffworks.com/gear.htm.

Electronics skills are probably the most difficult to acquire. What really got me started was an incredible learning kit when I was eleven: the Radio Shack 150 - 1 kit (yes, I learned many things when I was eleven, including: you cannot jump from the roof of your house with a patio umbrella, and that you cannot jump to the bottom of a ten foot swimming pool with a hose in your mouth if your objective is to breathe air. Parents beware: eleven is a dangerous age!)

These kits have changed over the years, but the basics are still the same: check out the Radio Shack Electronic Kits, and in particular, their Science Fair product line.

Curious asks:
I always enjoy the robotic (artificial intelligence) episodes of FRONTIERS I noticed during the Cornell (the team with robots that could move in any direction without turning? They could also reverse spin the ball toward them.) match, the robots playing set plays.

After one particular penalty, one robot positioned itself near the opponent goal, and another robot positioned itself near the other side of the goal. The first robot passed the ball to the other robot, which caught the ball, then turned and shot the ball toward the goal. Before the ball could reach the goal the opposition swarmed into place to block the shot.

I wonder why the first robot did not bounce the ball off the other robot and into the goal to eliminate the catch-turn-shoot delay. Is there a rule against caroming the ball off other robots?

As I type this, I seem to recall a past tournament where robots were doing this exact thing, a sort of billiards style of soccer.

D'Andrea's response:
Very good question! Caroming the ball off of other robots is certainly allowed. In fact, we scored many of our goals by doing exactly what you described: combination plays, or very quick one-two plays. We actually did more than carom the ball off opponents or our own players; we passed the ball in such a way that a team-mate could intercept the ball and quickly shoot it on net. We have quite a bit of footage on our web site: http://www.mae.cornell.edu/raff/media/media.htm.

You bring up a very good point, however. At the competition in Seattle, our team was too surgical: a robot would only shoot or pass the ball if there was good chance of completing the play. In other words, we were very much playing for possession and control. Unfortunately, the rules in 2001 and the small size of the field were not conducive to a very controlled game. The analogy here is of soccer vs. hockey: good soccer teams play a controlled style of play, and move the ball around amongst team-mates constantly. Hockey, on the other hand, is not as controlled a game: you often see teams dump the puck into the opponent's end, and chase after it. In 2001 we tried to play soccer, when we really should have played hockey! The situation will be substantially different in Japan this year: the field and the goal width are fifty percent larger, which will favor more controlled game play.

Hannah asks:
What are some of the more clever innovations you've seen in the last few years of RoboCup competitions? Where do you think inspiration comes from?

D'Andrea's response:
I think that the two most important innovations in our league have been omni-directional drive mechanisms and dribbling mechanisms. The reasons that these two electro-mechanical designs have been innovative, however, are not the ones that readily comes to mind to most people.

Consider the omni-directional drive mechanism. This innovation (which incidentally has a long history, so it is not really an innovation per se) allows a robot to instantaneously and independently control its rotational and translational degrees of freedom. One would thus think that the main contribution of this mechanism is improved maneuverability. In fact, this is not true: look at the videos from the 1999 competition (http://www.mae.cornell.edu/raff/media/media.htm), and compare them with the footage from 2000 and 2001; the two wheeled robots are just as maneuverable, and are in fact much quicker and faster.

The main contribution of the omni-directional drive is that it is conducive to extremely efficient path planning and control algorithms that are nearly optimal (check out http://www.mae.cornell.edu/raff/Papers/nagJRR02/
nagJRR02.htm ). As a result, we can allocate a very small amount of computing resources to trajectory generation and path planning, and use the bulk of our computational resources for high level strategy and decision making.

As an analogy, think how difficult it would be for a human being to play a sport if they had to consciously control the individual muscles in their arms and legs. In fact, our conscious control is much more high level than that: we just think about kicking the ball to a certain location, and it just happens (it takes a long time to learn this skill, but that is a topic for another day!).

The second innovation is the so-called dribbling mechanism which we introduced in Australia in 2000. This mechanism simply allows a robot to control the ball without violating the holding rules. Most people erroneously think that the main purpose of this device is to prevent other teams from getting to the ball. In fact, it is extremely easy for a robot to strip the ball from a dribbling mechanism (just like real soccer! ) The main reason why this innovation has changed the game is that it finally allows teams to pass the ball. Before this device, it was impossible to purposefully pass the ball to an opponent -- prior to the 2000 competition, all passes were either "emergent" (the ball was directed into a general direction with the hope that one of your own robots would get to it first), of from set plays such as free kicks. Dribbling has greatly opened up the possible strategies that a team may develop, and rewards intelligent and sophisticated play.

On their own, the omni-directional drive and the dribbling mechanism are simply good designs; when considered from a systems perspective, they have greatly changed the game. Inspiration for these designs comes directly from real soccer and sports: for the omni-directional drive, the motivation was to simplify the low to mid-level control issues that human beings take for granted, allowing more time for high level reasoning; for the dribbling mechanism, the motivation was to duplicate passing in human soccer.