We began our design phase by brainstorming various ways to build our robot.  We identified six areas that we had to evaluate to determine which alternative best met our criteria.  These decisions dealt with whether or not to use a kicker, whether or not to use rotating flaps to control the ball, how we should arrange our wheels, whether or not we needed extra batteries, what shape we should give our robot, and finally what materials we should use to build it.

The main decision over the kicker what whether or not it was useful enough to use.  The arguments for a kicker were that it may be harder to defend against and that it could be used on defense to clear the ball from around the goal.  The arguments against it were that it added mechanical and programming complexity, it added weight, and the added components would raise the cost of the robot.  In the end we decided to go without the kicker, but to leave open the possibility of adding one later.

The control flaps were to be extensions that would push the ball towards the center of the front end of the robot.  These could be used to give us better control of the ball, give us better accuracy in shooting the ball when used with a kicker, and it also helps simplify the movement of the robot since it reduces the need of precise positioning.  Still, just like for the kicker it adds mechanical and programming complications, added weight, and more components.  So, just like for the kicker, we decided to go without them.

The decisions over wheel arrangement dealt with whether to use a differential drive or synco drive.  Differential drive is where the two drive motor can work independently of each other.  this allows for good maneuvering, but if the motors don't turn in the correct relationship to the other, it might not go in the right direction.  In synco drive, all the drive wheels always turn in the same direction at the same time.  This gives you the advantage of keeping your robot pointed in the same direction regardless of which direction it moves.  This keeps you from having to keep track of its heading, but it adds mechanical complexity.  Because of the mechanical complexity of the synco drive, we decided to go with differential drive.  We hoped to be able to make up for its shortcomings with programing.

The question over whether or not we needed more batteries dealt with the concern of whether or not the Handy Board batteries would be sufficient to power the robot.  After looking at the capacity of these batteries and power requirements or the robot, we determined that they would be sufficient.  Still, as a precaution we decided to leave room in our design for in case our calculations turned out wrong.

Concerning the robot's overall shape, we discussed using a circle, square, or triangle.  We decided to use a triangle since it required less material than the other two and would make the ball deflect off its side at odd angles when on defense.  IN addition to this overall shape, we also decided to make the front end concave.  We expected that this would help give us better control over the ball when on offense.

Finally, we had to decide what to build it out of.  Our main alternatives were metal, plastic, wood, and Foamcore.  We finally settled on using metal, particularly aluminum, for the main support since it was sturdy, readily available in the stock room, and was fairly easy to work with.  One disadvantage is that it would cause the ball to ricochet more that we wanted.  To remedy this, we decided to use Foamcore on the edge of the base.  The hope was that this would give us better ball control.

Now that we had decided what we would use to build our robot, we just had to figure out how to put everything together into a tentative design.  From all this, D.A.R.T. was born.

Requirements and Specifications
Design Criteria
Body-Of-Knowledge
Evaluating Alternatives
Selected Design
Schedule
Building and Programming
The Competition
Conclusion
Meet the Team
Images
Links