[artdutra04]

Originally Posted by ManicMechanic

Any ideas are welcome, but I'm especially interested in some things we've unsuccessfully tried to reverse engineer:

1. A spring-loaded launcher - Vexlabs's ping-pong launcher looks like it uses a rubber band, but we can't figure out how to make the hinge that activates the spring. The view is blocked by plates.

Today's your lucky day.





All this uses are three of the rubber links, available from VexLABS. The rubber links provide for the 'hinge', and the extra elastic band adds more 'oomph' to the launcher, as well as give the launcher a better default launch angle than the previous picture. More information and drawings from this project will be coming shortly. ;-)

Originally Posted by ManicMechanic

2. A conveyer belt mechanism - The video from Team 40 is shows this, but we've not been able to get sufficient friction using tank treads and plates.

The first thing you should do is to have the Vex tank tread moderately taught - there should not be able 'slop' in the tank tread. This will ensure that the tank tread keeps a contact force on the balls, as otherwise you'll have great friction near the wheels and bogies, but in the spans between them the tank tread will flex and the ball will stop moving.

Also try attaching a ton of the Vex zip ties onto the Vex tank treads. These work great for helping push the softballs along tank tread elevators. ;-)

If you want some great pictures of Team 40 and all the other robots that were competing at the Connecticut Vex Championship, just look on the gallery page of the ConnVex website.

http://connvex.org/?page=gallery

Originally Posted by ManicMechanic

3. Holonomic drive - We can visualize a static model of this, but don't understand dynamically how it moves and how to drive it.

Originally Posted by Dylan Gramlich

Talk to artdutra04 about this. he built a very succesful and impressive Holomonic drive.

Thanks Dylan. To learn about the basics of the holonomic drive system, I'd suggest that you read this white paper:

http://www.chiefdelphi.com/media/papers/1836

In addition to that, you can see this picture and accompanying thread for more details as well as the EasyC code to create of the Vex holonomic robot that I built last fall/winter.


http://www.chiefdelphi.com/media/photos/22353