things to keep in mind while in the pits..

Technical Technical Discussion
1

Hmm things to watch out for, look for, plan for:
(Some of these have been said, im just going through everything that I can think of that I’ve encountered)

  1. Set screws (make sure they are tightened)

  2. electro-mechanical feedback devices are properly calibrated (pots)
    I’ve some bad things happen when you forget to tighten a set screw that attached a pot to the shaft; also, if it isn’t calibrated right, I just blame the programmer. (sorry Eric V/Adam B/Mini Taz - and all else I’ve badgered in the past)

  3. Plastic shavings/metal shavings - they can get into places they aren’t supposed to…like the exhaust valves for solenoids, causing the valve to stick, or get stuck in a position that is undesirable. Metal shavings and motor controllers, or any other electrical device = bad.

  4. Broken pneumatics connectors, cuts in the line, improperly seated line. try to build systems that use pneumatics that don’t come into contact, or close to coming into contact with the connectors (like our plow for 2002) or you might repeatedly break connectors. Latex tubing and some re-shaping was the fix, but try to prepare, and design for that, while the metal part wont break, the plastic parts are not designed to be used as a bump stop.

5)Plastic chain that is “as” strong as steel chain - we had some weight issues, so we tried to use the plastic chain…not only is this chain very expensive…its also “NOT” as strong…we broke the chain in less than ten seconds. Back to the trusty steel chain. Might be good for some applications, but it couldn’t handle the load of our DT. A more brittle material, constant bumping, or other sharp impacts could cause the chain to fail.

  1. (Brass) bushing that might not be a perfect fit. Bushings are there for a reason, even with c-clips, if a bushing is aloud to wiggle free, it could cause a lot of damage to the systems it was designed to protect, put a lot of stress on a drive mechanism, or other bad things that could jeopardize the lifespan of a system. Sometimes, it only takes one “event” to kill a system, even if it continues to function, because as time, and the parts wear on. Eventually the system could fail, only takes one initial even to cause a snowball effect.

  2. Ok, this is for “Master” miller (those of you, who know me, know what im about to say). Yes, brass is a fine material, easy to machine. Now, I would say that I machined about 15 brass shafts, even though I argued for steel…ok, to the point, don’t be afraid to opt for the stronger material even though it might weigh more…just because the time spent repairing said part might out weigh the added weight.

8)Make sure you have assorted hammers/mallets/50 pound sledge…sometimes, in this field, it is necessary for something called percussive maintenance, don’t be afraid to give something a few whacks with the hammer to get it working.you’de be surprised at how fast you can get something done with a hammer, and it is stress relieving.

9)if you have to machine something at competition, and there is a long line, don’t be afraid to strike up a conversation with the lone machinist in the shop trailer…quickly earn his trust…and use the machines…because that’s what I did, and I was out of there before everyone else. if you can machine (been doing it for more than 3 years) and your not afraid to take some initiative, then see if the guy (or gal) will let you, you’ll be done and outta there in no time, and you can make the part the way you want it, without having to draw it out or try to explain what you want.

  1. tighten tighten tighten - always go over the entire robot, and double check, or re-check and make sure everything that is supposed to be tight, is, so that you don’t have a major system just fall off your robot during a match, or even if the part/system doesn’t fall of the robot, the fact that it isn’t properly constrained can lead to other problems. Damaged the drive mechanism and the such.

  2. dead batteries, always make sure you have at least 1 batteries fully charged. Also, you should have a millimeter, or you can build a tester designed to just plug into the batteries with the same style connector to quickly check what voltage they are at, which is what we did, works great, and hasn’t let us down yet.

12)think about using Velcro to fasten the batteries to the robot, a 1 inch wide strip on the bottom (or more) a few inched long will hold that batteries upside down. I used a 2 inch wide 6-7 inch long strip on the 2002 robot, had to be Hercules to get the batteries out.

  1. Make sure all the electrical connections are solid, any loose connections can spell disaster, having a hot wire flopping around with all of your electrics can mean some major work later on. Should always use heat-shrink tubing on the connections so that there is less exposed connections.

  2. should test the systems in the pit as much as you can, perfecting them, or insuring that they are functioning, don’t be afraid to use white lithium grease (or just wd-40, or whatever you use for lubricating parts) with the drive train, keep the chains lubed, and other rotating parts that might be tight, or stick.

Obviously there are a lot more things, in the past three years I’ve encountered many different challenges, that really run the spectrum, but I’ll save them for another post. (Note: written on only one cup of coffee…so im sorry for any spellin

2

Addendum:

No matter how hard you try to block the aisle for saftey when testing something on your robot, (arm, fixed drivetrain, autonomous) a spectator always walks right into your test and a near miss results, if your lucky.

3

yea, what else am I forgetting, say its early morning, and your eating breakfast (in my case, and Boston cream dessert) stand far enough away from your robot, so that in case someone decides to test the arm, it doesn’t rip the donut out of your hand, and flings it across the pits. (needless to say, I was not a happy camper.) I’m sure there is a lot of things thats missing here, so, what else is there to plan for, watch out for, remember while in the pits to keep your robot in working order, and the pit crew happy.

4

For that matter… As long as we’re mentioning stuff in the pits, always remember your safety gear as long as you’re in your pit. Or doing anything with a power tool. Also, if your robot has a huge arm that moves around above head height, you should probably seriously consider a few bump caps/hard hats in addition to the standard safety glasses, gloves, etc.

Other thoughts:

Roll pins suck. Atleast they do for power transmission. Either the pin is too small and will shear, or the pin will be too big for your shaft, and your shaft will be weakened enough that it will yield. This happened when I let a machinist change the first run design of our tranny last year. After I spent several days machining properly keyed shafts as originally designed, things worked much better.

Also, for securing our battery last year, we used a 2 inch wide velcro strap. It was a long strip of female velcro with a short strip of male on one end and a plastic loop on the other. you wrap it around the battery and some piece of structure in your battery holder area, thread the male end through the loop and tighten it down and stick it to itself. Very strong, very quick and easy to remove.

Try to standardize on one or two bolt sizes and then buy a lot of wrenches and sockets for those sizes. Cause otherwise you’ll never be able to find the right wrench/socket/nut/tap/washer when you need it.

Secure your electrical wiring to keep it out of the way of moving parts. One year we had an arm that folded against our chassis near the battery. Predictably, in one round, the battery cable was hooked by the arm as it was unfolding, and our robot rapidly stopped working.

If you have time, make spares of critical parts or parts that are exposed to “vigorous interaction” with other robots. Unless you have made these parts very strong, there’s a good chance something will happen and you’ll be left scrambling to repair them. Corollary: make these parts difficult to break. Our robot last year had a long arm to grab the chin-up bar. We chose PVC as a material because, while heavier than similarly strong aluminum pipe, it is extremely elastic and bends a lot before breaking. We were wrapped around the pole several times and came out fine.

5

Be courtious to the teams around you. and keep your teams stuff seperate from other teams gear.

6

A few things not mentioned

A) If you can think of 10 things that can go wrong…the 11th one will :eek:
B) Keep your area clean and organized. How many times have you needed a tool in a hurry and couldn’t find it.
C) Keep the most used tools on your robot cart. Things can go wrong just as you are about compete.
D) If you see a team that seems to be struggling go ask them if you can be of assistance.
E) If you accidentally break another robot during competition be gracious and offer to help them rebuild. Teams will look up to you.

*throws $.02 at kitty, who promptly eats it.

Wayne Doenges
Team 1501

7

Dont forget the safety goggles… as i pointed out before in another thread… only a few days ago… the safety goggles saved my eye… :slight_smile:

8

yea, good mention of Murphy’s Law, this year I’m counting on the robot stealing my donuts in the morning, and planning accordingly. On a more serious note, I’ll have to repeat: Organization in the pits. If you aren’t organized and you can’t find the tools you need, then you can’t perform the tasks at hand. so while last year I was in charge of our pit (title: Pit Master Chief as well as the lead mechanic) it was one of my duties to insure the pit was clean and organized (as far as the tools and supplies directly related to the robot). This year I am a mentor, so I guess I’m supposed to try and teach people what I’ve learned over the last few years. It’s gonna be hard to watch from the sidelines as this years robot gets built. Although I may get props on designing the gearboxes this year. JVN (I’m about to make a shameless reference to highlander) “There can only be one”! just kidding john. I’m looking forward to seeing the goods from Clarkson’s team this year, Hopefully I will be in charge of the transmissions, I have spent many hours designing, and making things interchangeable,(yea thats right, bringing in interchangeability for added flexibility) but the fact is that me designing this years gear boxes is not a sure thing (yet)(but I hope I get to use some of my designs). Time to train a small army of younger kids, and then they could build it. 0000 I like the idea of having a small army… :smiley:

9

These are terrific suggestions. If someone or a group is up to the task, these could easily be abbreviated and listed, like “Hints for in the Pits” along the lines of “18 Hints for Rookie Teams” that NEMO put together for a one-page handout (see the white papers for copies.) It would be great to be able to hand out things like this at kickoffs, etc. as there is a lot of practical information here.

I would be willing to help but don’t want to take this one solely.

10

I would be willing to help, I could come up with an abbreviated version of all the ideas on here, or at the very least help to produce something to hand out like you’ve suggested.

11

Take a look at the NEMO hints format and then just start listing the ideas (offline). Try for just one sentence or two for each. They can be edited later. Keep adding ideas as they get posted and keep track of the post-er and team.

I think this will be much appreciated by all, especially the rookie teams.

12

I’m surprised this hasn’t came up.
When at all possible try to keep isles clear. The isles are not the place for lawn chairs and picnics. Sure you many stop and have a conversation but I’m talking having robot carts, robots, and other large things just sitting in isle.

Also arrange to have a pit crew if you have a large team (a normal amount would be 4-5). That way only the pit crew is in your pit and you don’t hang out into the isle and it will be a lot easier to fix the robot or get things organized

13

thats what we have, we have a “pit crew” as well. it is around 4-5 people like yours, I was, as I said earlier, the “pit boss” or pit chief. (and as a halo fan, it was turned into “Pit Master Chief”). Having a lot of people around is nice, but the pits are small, and having too many people can cause a serious problem. I’ve had it so crowded in the pits that I was seriously stepping and hopping over people while they leaned down so I get to a tool, or the robot. Thats when you know there are too many people in the pits. Last year we where very strict to as who could be in the pits. and it worked out good. I don’t think we ever really ran into a problem of over crowding (at the regionals). We where less strict down at nationals, and again I was jumping and climbing over people to get to tools and other important things, because why everyone talked, me, Bryan (bryno tho rhino - sorry buddy, had to),my brother, and a few others where trying to fix and maintain the robot.

So, I’m gonna take a look at that NEMO thing, and get a general format down from it, then I’ll begin. I’ll keep you guys posted on how it comes out. I’ll make sure to include who suggested what, and what team they are from. Keep the great ideas coming.

14

Here is the list I came up with.

PIT TIPS FOR FIRST TEAMS

  1. Wear safety glasses. Make sure to bring enough for your whole team and visitors to wear while in the pit area.

  2. Keep pit area neat and organized. This will make it much easier to find tools when last minute fixes are required and judges love to see it.

  3. Develop a pre and post match robot checklist. This list should include all high maintenance items on the robot as well as a basic list of things to check before and after matches to ensure the robot is in it’s best working condition. Include:
    i. Wiring connections
    ii. Structural integrity
    iii. Pneumatic pressure/line integrity
    iv. Battery power
    v. Tightness of bolts, connectors, etc
    vi. Working condition of mechanical systems
    vii. Program run through (include test with control system)

  4. Limit number of people in pit. Pits are small so keep only essential personnel. You can even have a pit rotation schedule to get more people time in the pit.

  5. Label all tools with team number. Tools get borrowed or misplaced at competitions all the time. Having the label will make it easier for others to return your tools. The same applies for batteries as well.

  6. Don’t be afraid to ask for help. If you don’t have the tool you need, the part you need, and/or don’t know how to solve a problem, ask around. There is a lot of expertise at FIRST competitions and always people willing to help out.

  7. Keep aisles clear. Robots on carts, people, judges, and inspectors all need to be able to move through the aisles. Keeping everything out of the aisle makes things easier on everyone.

  8. Charge extra batteries. Make sure to always have charged batteries including power tool batteries.

  9. Use available resources. Most competitions have professional machinists and a machine shop available to teams. Make use of them and their expertise. Many competitions also have a practice field available for teams which is a great way to work out programming and mechanical issues as well as provide extra driver practice.

  10. Be careful when testing your robot. Many robots have large moving parts. When testing those in the pit, make sure to keep the area clear and to warn those around you.

  11. Use the tether. Never use the radio modem in the pits, always use the tether.

  12. Know where your field crew is. Always keep tabs on the field crew so that they are aware of robot issues before matches and make sure they are available for pre-match strategy.

  13. Don’t lose field buttons. Collect the buttons at the end of the day and put them in a safe place that everyone knows to make sure they aren’t forgotten at the hotel the next morning.

  14. Keep essential tools on cart. Tools that may be needed for last minute repairs on the field should be kept on the cart.

  15. Use time wisely. For instance, when the robot leaves for match queue is a perfect time to clean up the pit area. Use slow times to make extra spare parts. Make a plan for repairs and wanted changes.

  16. Nourishment for pit crew. Have someone make sure that the pit crew gets food and drink throughout the day. It tends to get very hectic in the pit and food/drinks tend to get forgotten.

  17. Have a pre-set plan. Have set responsibilities assigned including pit crew, awards, scouting, field team, etc. Also have a plan for robot repairs and changes to be done. Get all these plans set before going to competition.

15

Alittle off topic but along the same lines:
Also, it is a very good idea that you do a system check once you get to the field during a regional or championship competition. Things can happen from the pits to the field and ruin your match. Also, it is good to have a system preparation battery on the robot in the pits and change to a fully charged battery at the last moment at the field so you don’t have any battery failures.

Wire tires are also a good way to hold a battery in the robot. This year we had 2 strips of Velcro (3/4 inch wide) and failed almost every time during a big wreak. Since then we backed up the Velcro with wire ties and they usually did not fail.

Also, alway have your batteries charging! It is a great idea to assign someone the job in the pits to always monitor your batteries. Batteries can make a big difference.

16

Post your team’s Match times, so you stay on schedule in the pits. A lot of teams use small white boards for this purpose.

Keep an area for programmers to work and plug-in (I keep finding tools and metal shavings on top of my laptop).

Assign a Pit Chief to be responsible for:
[font=Wingdings]vKnowing where all tools and spare parts are stored and keeping them that way.[/font]
[font=Wingdings]vMaintain a list of items to be purchased, supplies to replace, etc. [/font]
[font=Wingdings]vTrack tools and parts borrowed from FIRST and other teams (the Pit Chief can write thank you notes in his or her spare time) and tools loaned to other teams .[/font]

17

I’d like to get this version finalized so it can be put in the white papers and used at the upcoming meetings.

Since Anne did a great job at summarizing, why don’t we take her version and then I need you all to look over your comments and add anything that she forgot from your comments. We are up to #17, so start with #18. You write your comment and I will add it. I have added a “thanks” line at the end with all your team #'s and your first names (coreyjon-what first name do you want to use?) To keep this to one page, back and front, we have room for 3 or 4 more hints. So look it over and let’s finish this by next week.

18

I apologize for not having a final version completed, I agree, Anne did do a great job of summarizing what we have all said. I started working on a one page summary of what others have said, but I have run into problems with a Mat Sci Lab that then seemed to become almost like a black hole, and so that is where most of my time and effort has been going. I agree this information will be more useful before events start occurring, and is good to get to teams ASAP, so that they may start planning, and integrating ideas into there team SOP’s. (standard operating procedures). I look forward to the final copy of this, as I’m sure it will be a great help to rookie, and veteran teams alike.

19

[quote=Anne Bergeron]Here is the list I came up with.

  1. Nourishment for pit crew. Have someone make sure that the pit crew gets food and drink throughout the day. It tends to get very hectic in the pit and food/drinks tend to get forgotten.
20

Ooooo!
I really like that one!

I think 229 owes a few hundred (thousand?) thank-you notes.

Good Idea Mark,
John