It’s later this week, so here it is!
OSIZR: Open Source In the Zone Robot by ALBA
Much like last year, the goal was to build a simple robot ideal for new teams and the early season. In order to keep the robot simple and cheap, a reverse double four bar was specifically avoided. The only other major goal for the robot was that it carry the mobile goal around and stack while carrying it. Many other decisions (such as the parts to use and how things were built) were guided by the goal to keep the robot minimalistic, easy to build, and cheap.
BOM
spreadsheet
It’s very similar to last year. I initially imagined it would use less metal, but the mobile goal lift ended up taking up a decent amount.
Total cost came out to a little under $1300.
I’d say this represents a good list of standard parts to buy and also represents (approximately) the minimum price tag of a competitive robot.
Code
The code is on github
It was programmed using PROS (of course :D).
It demonstrates basic operator control programming and includes a simple proportional position controller and slew rate control for the lift. Oh, and there’s a struct. People seem to be using those more lately, so maybe a good thing to try out if you haven’t yet.
Discussion
While I’m not trying to argue that RD4Bs aren’t the best type of lift this season, I do think teams should keep in mind that the speed with which they can stack is as important as the height. If you are able to score all of the cones at your first tournament, then you are doing pretty well, but if not (most early matches won’t get close), then you should build a robot with matching height and speed capabilities.
Also, RD4Bs are a pain. Yes there are a lot that seem to work perfectly on youtube from skyrise worlds, but those are from top-tier teams who spent a whole season on them. If you’ve never built and competed with an n-bar linkage before, then I wouldn’t go straight to the RD4B.
You’re welcome to argue/discuss below
The starting bar: The 3.25" wheels don’t seem to have a problem with the starting bar, but the gears on the drive do, especially when holding a mobile goal, so if you were to build this, you probably should use chain (which I didn’t have enough of) or pillow blocks (and maybe 4" wheels). Also, the arm towers would need the bottoms cut off (which I didn’t want to do because now I need to build a 24" robot and I’ll want 18" c-channels).
This is getting too long. There’s more I could say, but I’ll save it for questions. I’m guessing tl;dr set in about two lines after the video anyway.
I didn’t take a bunch of pictures this year or finish a CAD model (partly because I’m guessing no ones cares too much), but if anyone wants more details, then I probably can provide pictures or at least explain. Let me know what you think, criticism is welcome!