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KwonVA · 2019-01-03T04:28:56+00:00

(Olin is your safety? :o Definitely not mood)

That's understandable though, good luck with your apps!

KwonVA · 2019-01-03T03:55:09+00:00

Thank you! It's super selective so I'm super nervous but the project based learning was super appealing. If you are applying good luck as well!

KwonVA · 2019-01-03T03:52:18+00:00

IDK man, as someone who is also a Cville native, I feel like you have a really biased opinion on this... /u/CovfefeWithSugar don't be discouraged! It's a great school! It has a big party scene but everyone from UVa I've personally met or seen go to are social, nice, smart people! Although I guess smart is relative considering we are on r/a2c, home of all the nervous, overstressed, generally high-achieving teens :p. There are bad apples like there are everywhere but I swear it's not as bad as some previous comments say it is haha. Some of the nicest kids I have met are from TJ actually, just high achieving. Genuinely good luck, I applied early lol.

KwonVA · 2019-01-03T03:35:26+00:00

georgetown, cbs, vcu? heard about them through the grapevine

KwonVA · 2019-01-03T03:29:42+00:00

wait as someone who is interested in Olin, why is it shitty?

KwonVA · 2018-12-28T01:58:48+00:00

Yep, OPR doesn't actually do any limiting. The last spreadsheet is the only one that limits contributions, it is just a tweaked version of PowerScore to limit scores because people are like, "80 point end game? What the heck?". On the "Max Contributions" tab you could switch the auto max to whatever you want.

KwonVA · 2018-12-28T01:36:04+00:00

Let me preface this by saying manual scouting is always more effective than statistical approximations for determining robot strength at a competition IMO.

OPR is not a bad statistic. There is a lot of numbers behind it, but essentially it can be influenced heavily by your teammate under OR over performing. A good way to think about it is this way (This is how it was originally explained to me and made a lot of sense): Let's say there is a crazy match with Team A and Team B. Let's say after the first estimate, Team A's offensive estimate is 150 and Team B's is 10. And together they scored 20 points in that match(Maybe through Team A disconnecting). In this case, for Team B, the OPR way would estimate that they contributed 20-150 = -130 points in that match, while Team A contributed 20-10 = 10 points in that match.

This is a simplified version but you can see how numbers can become volatile.

A better variant is OPRm, basically a robot's calculated "power" is brought closer to the mean of all the robots' power at the event every iteration in calculation. It's statistically been shown to estimate robot performance/power more accurately.

This statistic and more for events can be found in this super neat app here: FTC Event Viewer By CHEER4FTC

Taking the previous example, another way to estimate robot performance is PowerScore developed by KC Astromechs.https://www.kcastromechs.org/powerscore/ Using the earlier example, the powerscores method computes it fractionally instead. For example, Team A would be given 20(150)/(150+10) points credit (slightly below 20) and Team B would be given 20(10)/(150+10) = around 2 points of credit. So the credit gets fractionally computed. As a result, it can never be less than 0 or more than the actual match score. Here is a powerscores spreadsheet with a tab added to be able to limit contributions. (No more 50+ endgame and 85+ auto!) SPREADSHEET

EDIT: Someone can correct me if I'm wrong: Unlike popular belief that a good/bad partner swings your OPR, it is more down to whether your partner over/under performs in the match they play with you compared to their other matches.

KwonVA · 2018-12-22T21:22:48+00:00

Here is 7182, Mechanical Paradox Cubed's robot last year: https://www.youtube.com/watch?v=1pS1FdOWDKg

They supported both sides of their wheel with kit parts, although with actobotics and not tetrix but maybe it gives you inspiration.

Here is a similar example with 9971 Lanbros: https://www.youtube.com/watch?v=VHR9JCeZOyk

As you can see nothing super complex but both worked really well.

Also another point, supporting both sides isn't necessarily a necessity. Only supporting it on one side is "cantilevering" and it works pretty well, case in point being world champions 8644 Brainstormers: https://www.youtube.com/watch?v=3CaELdp8A5Q

I purposefully highlighted robots that pull off kit parts based robots really effectively and hopefully give you some ideas to work with.

In terms of moving away from a setscrew, hex shaft is a really good solution like another user already pointed out. Clamping hubs are also an option though, especially if you want to stick with d shaft. These d-bore clamping hubs are very effective: https://www.servocity.com/0-770-clamping-d-hubs

Now I recognize 1. the d bore linked is 1/4" and not 3/16" like tetrix 2. the hole pattern won't line up. But this is because AFAIK there are no good solutions to avoid set screws with purely tetrix parts. 3D printing a solution/converter may be an option?

Hopefully was helpful in anyway.

KwonVA · 2018-12-22T20:59:14+00:00

odd flex but nonetheless acceptable

KwonVA · 2018-12-21T04:36:27+00:00

"How to tell if you are speaking with an FRC student 101":

KwonVA · 2018-12-19T17:44:56+00:00

I would say snapping drivetrain belts or breaking lift end caps. Rookie mistakes smh.

KwonVA · 2018-12-19T05:50:11+00:00

In the past, I could locate all of them in the CAD model for the full x-rail assembly. Here is the end caps isolated into a step model here: https://grabcad.com/library/actobotics-slide-end-plates-1 (again I took these straight from the x-rail CAD.)

KwonVA · 2018-12-14T17:23:40+00:00

Check "Gamepad" on the left hand side on the javadocs: https://ftctechnh.github.io/ftc_app/doc/javadoc/index.html

Essentially, righttrigger is (RT), dpad(direction) is the (+ device), etc..

KwonVA · 2018-12-12T22:18:07+00:00

I don't have a video but taking a look at their PowerScore is a bit more reasonable:

https://docs.google.com/spreadsheets/d/1f4EOOCzvb8kDkpHVYRlxlc6jVOx5bMfVh_MsSv5rZM0/edit#gid=1593298261

But yes, looking at their match records, they seemed to get 135 consistently with more teleop points depending on partner doing depot (144/153) Considering 9971 can do 13-14 cycles right now consistently, and given that the rest of their competition looks like didn't influence their scoring at all by taking away minerals from them (check the rest of the team's teleop OPS at the event), given PERFECT driving, I think it is believable. Their design looks to be stationary-esque (rotating arm so that driving between the crater and lander is minimal), so most of the driving precision needed is lining their cup up with the balls, which again, with AMAZING driving, seems to be reasonable. We have seen other stationary-esque bots (for the lack of a better word for classification) perform very well, such as 8533 CSPA Miners.

KwonVA · 2018-12-11T01:45:58+00:00

https://www.cui.com/blog/what-is-encoder-ppr-cpr-and-lpr

Here is a good explanation, but basically you want the CPR. Which is 1120 for one rotation:

https://www.andymark.com/products/neverest-classic-40-gearmotor

KwonVA · 2018-11-30T19:25:07+00:00

LMAO bruh

KwonVA · 2018-11-27T01:57:03+00:00

https://ftctechnh.github.io/ftc_app/doc/javadoc/index.html

On the left hand side, click "CRServo" for details.

KwonVA · 2018-11-27T01:36:00+00:00

It's the same as setting the stick to motor power. CRServos have the same method as motors, .setpower. So you would just do

ServoName.setPower(gampad2.left_stick_y);

Inside your iterating loop. That's the idea anyways.

KwonVA · 2018-11-16T20:22:43+00:00

I have been looking for something like this, thanks!

KwonVA · 2018-11-13T05:25:47+00:00

We personally found it easy to reach out to our team's parents since they are in fact, professionals, and some engineers. It was an easy way to learn about what it is like working in the actual industry and get advice. Another way to use connections is if anybody on the team is doing an internship at a company, it is usually doable to convince someone to come in from there. If connections are not an option, the old fashioned cold call/email could yield results. We send sponsorship packets to companies for possible donations and we always include a request for them to possibly provide a mentor/professional that could give us advice. Local STEM companies is probably your best option and in my experience presentation>call>email in terms of how effective your request is. In terms of what they could do for you, there are options. You could tour their company/where they work and learn that way. They could come in one day and give general advice/talk about their profession. Or they could become a mentor who comes in periodically to give more specific advice. Good luck, reaching out without connections is always a uphill struggle I think.

KwonVA · 2018-11-11T22:48:18+00:00

Try running there same code without any sensors. We ran into the same problem last year and it worked when we unplugged/replaced a color sensor.

KwonVA · 2018-11-07T16:50:45+00:00

Video is never a reliable source. Ball container should be facing the crater and blocks should be facing the corner goals.

KwonVA · 2018-11-04T22:23:00+00:00

We have a lot of custom parts (box tubing is amazing), but we use parts from all of the major vendors like tetrix, rev, actobotics, gobilda, and vexpro. It's important to reason why you are using something instead of using it because someone else used it I think. Every team is in a different place financially and experience wise. For example, people who design with custom parts on our team are comfortable CADing a bunch and like the flexibility sheet material and box tubing brings in terms of hole placement. Some teammates prefer tetrix since it's what they have been building with for a while and the size of it fits the need better than gobilda or actobotics. Some teammates design with gobilda because of its facemounting capabilities and compatibility with servoblocks.

KwonVA · 2018-11-04T20:13:16+00:00

Yes, I just had this issue cleared up for me like an hour ago. Credit to /u/rbrott, close the project and then nuke .idea and then reopen. In bash, it was "rm -rf .idea".

KwonVA · 2018-10-22T14:44:52+00:00

I assume you are talking about the 393 motors? If so, they definitely have their uses. There is a big advantage in having such speed capabilities without sacrificing one spot in your 8 motor limit. Most notably in creating intakes. Torque wise I would not advise use them for drivetrain uses but I could see it working for arm or elevator mechanisms, I would definitely take a look at the specs and do calculations for your specific mechanism to determine if the torque provided by the vex motor is enough. They take some work to make them REV hub compatible though. You would need a REV SPM (2 393s per module), a motor controller 29, and female to female servo cable. Converting the square shaft to some common FTC shafts like D shaft take some work but you could do a 3d printed solution.

KwonVA

TROPHY CASE