Quote:
Originally Posted by Jon Stratis
And that right there is what most teams have problems with. Building a "working mock up" that is similar enough to actually let you do what really needs to be done isn't always easy. What works with small, weak motors when supported off the ground doesn't always translate directly to strong, fast motors hauling around 150lbs. Getting the PID controllers set up correctly can be horribly time consuming.
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Fair enough, the difficulty of some systems comes from their scale. A servo motor waving a toothpick isn't the best way to test code for the arm of a 2011 robot.
I can say from experience however that the code for a swerve drive does in fact scale rather well. It took me possibly 3 days to port the code over to java, 20 minutes to tune the PID, and another 3 days to make it look pretty so we could debug things, (and likely 4 to deal with the nasty issue of analog counters in the wpilib).
The rest of the issues the system had stemmed from the unbelievable complexity of designing and building the darn thing (of which, to the credit of those who worked on designing and building it that year, there were very few.)
Quote:
Originally Posted by Jon Stratis
If you can build a working mockup that is sufficiently complex in one day for your programmers to use, why does it take 6 weeks to build the real thing?
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I do have to take offense at what seems to be deliberate misreading of my post.
It took 3 days to build the mockup. It did not take 6 weeks to build the whole drive. The base was working by the end of week 4 that season. The first I directly stated, and I believe you should have noticed, the second is rather easy to infer, which I assume you also did.
3 days does seem a bit short though. I would expect a team with fewer vex related components on hand to take more time due to the process of procurement.
Quote:
Originally Posted by Chris is me
Every team is run differently and is composed of totally different people of different skill sets. Some teams have barely 1 student who can write all of the robot code, some teams have a few students but no mentors, some teams have a mentor or two but no students, and others have entire software teams at their disposal. Exposure to control theory and advanced embedded control is similarly mixed.
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A rather good point. I was a bit more experienced at that time than what I imagine the mean would be.
I would argue that a team with the means to build an effective swerve drive is almost guaranteed to have at least one programmer with the experience and talent to figure it out rather quickly,
but such an argument would be based entirely in conjecture since I have experience only with two teams. It would stand to reason that I had not considered teams with a greater imbalance of resources between the programming and mechanical teams.
Quote:
Originally Posted by Chris is me
Even your own example is of a swerve drive that, in your words, had a configuration that did not work.
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Right, seems a component of my post is missing. I was sure I had typed it but voila, as I was going back to look for it it was gone. There was a bug in the wpilibraries. It caused the configuration to not work. What I had failed to mention (but which it would reason isn't too difficult to infer) is that the bug was indeed fixed (good god would I have had a rant to put up here if it wasn't.) in, if memory serves me well, approximately a snappy four days. The configuration itself was fine, and worked, again, if memory serves me well, flawlessly.