PDA

View Full Version : tri track mod



farmBot
11-08-2008, 09:12 AM
I wanted more room on my tri track and I didn't like how the back end stuck past the tracks. This is what I came up with.

This is the old top view.
http://i374.photobucket.com/albums/oo182/farmBot/1226156233.jpg

This is the new top view.
http://i374.photobucket.com/albums/oo182/farmBot/1226156330.jpg

I took the middle and turned it around, I also had to cut off the tabs the stick in the side of the track assemblies. I ordered the 6.375 inch aluminum bars from lynxmotion and added some holes and cut 1 inch off. I can clean up my drawing for the modifications to the bars if anybody wants to try this configuration.

darkback2
11-08-2008, 11:57 AM
Great solution. I too have noticed/taken some mild issue with the back end of a tribot. You should post detailed pics of your mod when you have the time.

DB

Adrenalynn
11-08-2008, 12:05 PM
I considered turning mine around, but couldn't with my arm configuration.

I am curious, though, it's a little hard to tell from those pictures - but did you extend the deck out? Doesn't look like it. Without extending the deck, how do you get "more room"? The number of square inches don't change. If you're putting stuff on it that is taller than the deck spacer height, I can see that, but putting anything with any weight there will severely impact balance and traction.

My solution was to extend mine vertically and then horizontally. I'm torn about saying much more until after the competition I'm designing for, but if you want more space with good balance, I suggest thinking vertically and making use of that space inbetween the motors...

farmBot
11-08-2008, 01:42 PM
I didn't make it physically bigger, I made it a more usable space for me. In the original configuration the motors divide the upper deck in two. My mod locates the motors near the edge to make a larger continuous space. My solution isn't the best for everybody, especially when using the lynxmotion turntable. I just wanted plenty of room for prototyping since this is only my second bot. My mod also cramps the area around the servo mounting hole, but I think I can rebuild my pan and tilt so that it still fits.

Original with room for one protoboard.
http://i374.photobucket.com/albums/oo182/farmBot/original_1_protoBoard.jpg

Modded with room for two protoboards.
http://i374.photobucket.com/albums/oo182/farmBot/modded_2_protoBoards.jpg

Comparison of old and new brackets.
http://i374.photobucket.com/albums/oo182/farmBot/bracketComparison.jpg

New bracket dimensions. The numbers at the bottom of the drawing are the ones I added to the Lynxmotion bar.
http://i374.photobucket.com/albums/oo182/farmBot/barDimensions.jpg

I'm not sure I understand what you're saying Adrenalynn. How would going higher make it more balanced? I don't want to put lots of stuff in the lower deck because I'm not building this for a specific purpose, I want things out in the open to change quickly.

Adrenalynn
11-08-2008, 02:03 PM
Putting a lot of weight out over the front of the tracks makes it front heavy pretty quick (in my playing with it), and it likes to stand-up on its nose over obstacles. Keeping the heavy part (batteries) down in the lower deck keeps the CG down and building upwards over the center keeps it forward/backward/left/right balanced.

Here's kinda what I was talking about:

4mem8
11-08-2008, 02:36 PM
Nice pics Adrenalynn, looking interesting.

4mem8
11-08-2008, 02:38 PM
Farmbot: Thanks for posting pics of your bot, please can you reduce them as they are pushing the forum out to the right. Thanks