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Build Day 29: Tweaking everything

We were working through the list of improvements that we saw from last night’s testing. We moved the polycord guides and that seemed to fix the jamming problem. We also riveted the guide rails and that made the shooter more accurate. We mounted the bridge device motor but not the device it self, that will come this week. The shooter hood needs to be refined to allow for more consistent shooting, we are planning to spring the hood forward so that the slack of the mount is taken up by the surgical tubing or other spring system.

We think the overheating issue with the Fisher Price motors is due to the CIM-sim blocking the air intake of the motors. We have  a couple solutions in mind and we’ll make those changes when we make a few other shooter improvements on Monday.

We mounted the camera to the front of the robot to mostly just to make sure the mount will be sturdy enough with all the vibrations and impacts.

We also mounted more our sensors today. The potentiometers form Digi-Key came in last night so we made the mount for that so it can measure the angle of the shooter compression bar. We also mounted our IR range finders in the elevator these will let us know where the ball is on the elevator. We are using them similar to line break sensors but they provide a bit more feedback because you can actually detect the curvature of the ball.

We also tested our robot on carpet for the first time. It drives better than it does on the gym floor but it’s still not very good, we have to adjust our center of gravity to make our pivoting much smoother. We also did barrier testing for the first time on carpet and with the shooter on. The robot climbs the barrier with out issue. It was a little scary the first few times but the robot really doesn’t want to tip. In fact if we go at a little higher speed the front wheels hit and the robot ends up driving on its back wheels until they hit the barrier. Completely skipping the middle wheels, that was the design but it seems to work.
We also tested ball collection and driving over balls. Collection seems to work well but we have a problem driving over balls. We haven’t tested with bumpers but we may change our bumper to design to take advantage of this handy rule clarification by the GDC (http://www.chiefdelphi.com/forums/showthread.php?t=100575). Bumpers at varied heights could help with several aspects of the competition.
Here is a quick preview of the robot in action, more to follow.

FRC#3847: Bank Shot + Barrier from Spectrum 3847 on Vimeo.


– Allen Gregory

“I don’t know if I practiced more than anybody, but I sure practiced enough. I still wonder if somebody — somewhere — was practicing more than me.” – Bird, Larry