Here is a video of a potential climber. It is a single purpose robot that climbs the corner of the pyramid and dump 4 discs into the basket on top to make a consistent 50 points. the key to getting the robot to climb over the crossbar joints is the use of a freewheeling star-wheel. The rotating/lifting arms provide 2 points of contact and the third point with the star-wheel should provide stability while climbing. What is not shown are the 2 retracting "V" blocks at the bottom of the robot that rest on the crossbars between climbing phases. Also a clamp to the corner upright bar would be required between climbing phases. The disc dumper could be spring loaded with a solenoid trigger release and dump the discs when the robot reaches the third level. Of course the devil is in the details...its one thing to make a little wooden model and quite another thing to make a 100+ LB robot to climb consistently in competition. I hope these ideas are helpful to some of the teams struggling with this concept. See the you-tube below.
http://www.youtube.com/watch?v=O9ouR...=youtube_gdata