DEWBOT IX Caterpillar Drive

Climb at SCH

Achieving a 30 point climb was a key aspect of 1640's game strategy for Ultimate Ascent^SM, with a strong bias towards climbing on the pyramid outside (thereby enabling other alliance robots to also score 30 points).

A number of concepts were considered and evaluated. The Caterpillar Drive approach was selected because it was perceived that:

1. The climb time could be relatively short, allowing significant scoring with Frisbees;
2. the climbing mechanisms would not interfere with a shooter; and
3. the concept was consistent with a low center-of-mass robot.

The Concept

The concept of caterpillar drive was to "simply" drive up the pyramid's corner pole: a slick, powder-coated 1½" steel tube at a 60° incline from grade, interrupted by two horizontal corners extending 2½" from the corner pole's surface. So this becomes a drive-train problem.

In order to cross the two horizontal corners, three (3) drive wheels oriented along the robot's drive axis will engage the corner pole. Each of these three drive wheels may be independently disengaged and lifted away to allow a portion of the robot to cross over a horizontal corner; only one drive wheel will ever be disengaged at any given time while climbing. Each wheel has a "claw" to hold it to the pole and to also provide the wheel with the normal force needed for traction. The claws terminate with bearings so as not to impede the climb with friction.

Skids on either side of the drive axis will rest against at least one pyramid horizontal at all times to prevent the robot from rotating around the pole. Since the robot chassis is shorter (27.75") than the distance between horizontal pyramid members (34.5"), the skids need to extend during climbing to insure that at least one pyramid horizontal is in contact with the skids.

---