Rookie Anxiety

At our last meeting our robot whizzed around, there were no major problems, and there was rejoicing all around (myself excluded). We have welded our aluminium chassis, made our grabbing arm, and we have mounted some of the pneumatics components. Our robot weighs 70 pounds, with batteries and all. My teammates our quite happy, and feel we are doing fantastically for a rookie team. I am extremely tense, as we have not even begun to work on autonomus mode and we have only begun practicing our driving. We still haven’t worked out our motor response curve compensation functions, so the steering is primitive at best. Everyone tells me my fears are unjustified? Are they?

Yes and No. As these last couple weeks come things are going to get more tense. You will have to get more done in a shorter time and of course you need practice. Programming is a concern but less of one because you can keep all your robot controls. Tweaking is really important in these last couple weeks. Any way you can improve your robot, with how it is controlled to labeling all your wire and organizing to make repairs during competition easier. It is easy to be anxious because tweaking and improvement is never finished. By what you’ve said it seem that you are in a good spot but just keep making improvements and you’ll be in a good spot for regionals.

You’re MUCH better off than the vast majority of rookie teams - and even some veterans. If you have a couple of good people the autonomous programming is not difficult and driving will improve with practice. Just keep chugging along and you guys will be fine.

Having everything built and working is a big accomplishment. Last year my team barely had a working robot, and it was our 3rd year. With two weeks left you should have no trouble figuring the rest out, as long as someone knows how to program and fix the motors. I am always tense also, but seeing how you guys are farther then us, you should feel pretty good. My hats off to you guys for building everything so quickly, good luck on the rest of your FIRST season.

Wow! Sounds great! You’ve got 20 days to go and you already have a robot moving around, that’s awesome.

One thing I’d worry about, as funny as it sounds, is that 70 pound robot. That’s awful light; is there time to design and add on a subsystem? Even if you just add ballast and even out your robot’s center of mass, it’s usually good to be around 130 for pushing and shoving purposes! Of course, if it’s 70 pounds to get off the ground easier and hang on the bar, you may not want to mess with it.

You’re doing a good job there.

Dude, it moves!

There a quite a few teams that don’t get that done until just before (day of) they ship.

The practice driving time will be invaluable. Being able to reliably and quickly get from place to place, with a changeing field is a valuable skill.

You now have three weeks in which to program your autonomus code with the working robot, then x weeks to continue work on it before the regional.

I think you are doing very well, for any team, let alone a rookie. We are just now welding our frame together.

Wetzel

We are all tense and exicted for what is to come. You guys are doing awsome we havent even finished our frame yet, you still have 20 days in which to twek you robot. Theres noting to be worried about. Remember even if things turn sour your in this to have fun so do just that.

You are well on your way to having a great bot. Our team has just started to put the frame together on Sunday. As of now one of our drill motors broke, and we are having to order another one. But even if we had both drill motors working, our power distrbution block has not yet arrived. We could not power the drill motors if we wanted to. We are stuck with a 130lb block with flashing lights. And, oh yeah, this is our 5th year.

I am sure that you will put up a good fight at the regionals. After all, you have 20 more days to practice. And with the bot moving, you should not be anxous, just as long as it is not tripping any breakers.

are you serious?? you still have like 20 days. We don’t even have a drive train, no programming, no sensors, no nothing, if we were in your shoes we’d be estatic

i think you are doing fine! Our team just got the robot moving two days ago, the arm is in construction, and so it the plow… we havent evey touched autonomous

no worries mate, things will work out

WOW!

Even without auto you are off to a great start. practice. practice. practice.
A fair robot with a good driver is better than a great robot with a fair driver.

We had a moving bot for 5 minutes last sunday. Then everything went back to machining for weight loss. We just needed to make sure it coud get up the 6 inches.

Great to hear about a Rookie doing well.

Keep having fun

I think that weight is one of the toughest obstcles that my eam will face this year, we have everythign built, but its heavy… We are weighing her in tomorrow and I would bet that our robot weighs 140-150lb’s.

any tips for removing weight, we used mostly angle aluminum for our chassis and structure, where is it ok to take away metal without severely reducing the structural integrity?

The trick is to keep in mind where you expect loads. There’s many engineerng courses on this topic… so I’ll give easier methods and some general guidlines that I have used in years past. They’re not perfect, but some ideas to look into.

In general, covering your robot with tiny holes won’t reduce much weight… especially in aluminum…

For example:

If you drill a 1/2 inch hole in 1/4" plate… it would take roughly 200 holes to get 1 pound of reduction. Try to get big bad square cut outs if you can, just be careful that you avoid removing too much material in areas where bearing and shafts run, and make sure that you think about worst-case sitautions. (What if my robot falls off the bar? If a robot on the bar falls off on me?! What if the corner of a robot drives into this particular point?)

Keep in mind that aluminum weighs about 35-40% the weight of steel… so you’re better off looking where you can reduce weight in heavy steel components such as gears and sprockets. If you have access to a lathe, reduce the hub diamter and width. If you don’t have a lathe, cheese-hole the steel where you can. Avoid getting too close to the teeth on sprockets and gears.

In general… if you really need to reduce signicant amounts of weight, reducing the thickness of parts by actually replacing them may be best. For many typical components (NOT ALL), 1/8" thick structural shapes are sufficient to function over typical light to moderate loads. 1/4" plate and other thick structural shapes should be reserved for where significant loads will occur.

Anywhere you see a square or rectangular plate, ask yourself if you could trim the corners off.

For light loads, do you REALLY need steel gears? Would brass, aluminum or nylon work? How about nylon chain in light applications?

If your frame has any box shapes that are greater than 1"… that might be over doing it a bit. If you’re using that 4" x 2" rectangular stuff… there’s PLEANTY that can be removed from that.

In general, assuming that you have a beam that’s supporting a load (such as an arm) you want to make sure that you keep the cheese holes bigger and more frequent near the end where the load is. Putting big cheese holes near the base where the greatest stress concentrations exist could lead into trouble.

Have you considered aluminum fasteners for certain applications? How about aluminum sprockets?

Just a few thoughts, good luck everyone!

Matt