Page 30 -

243_Legomaster_01.qxd 4/18/03 6:50 PM Page 2

2 Masterpeice 1 • Stair-Climber

Bill of Materials

These are the parts you will need to build the Stair-Climber as shown.

Introduction

Stair-Climber is the latest in a series of models based on the tri-star wheel concept.The
tri-star wheel is a triangular star-wheel arrangement in which the wheels can be driven
in a normal fashion for rolling over flat terrain (Figure 1.1), traversing a terrain gap
(Figure 1.2) or climbing over obstacles, as the whole assembly can be rotates (Figure 1.3).
One extreme obstacle for many robotic vehicles—but for which the tri-star configuration
really excels—is climbing stairs. When was the last time you saw something with wheels
actually climb a set of stairs?