The Emu Mini 2 is a small (less than 30x30cm footprint) low cost (less than $500 USD), 4 wheeled robot that is intended as a basic platform for the RoboCupRescue Confined Space Challenge competition. It is a starting point for students from high school (Year 9) upwards to experiment with solving real challenges in this domain.
Here are some notes from a build session recently held at Scotch College in Perth, Western Australia, where three of these robots were constructed with Design and Technology teachers from Christchurch Grammar School and Scotch College, and undergraduate students from Curtin University.