Modding FRC: Robot [Pics Update: Feb. 1)

Hi ya all,

So first, yes I realize this is not exactly a "PC mod" however I think some of you guys/gals here would find this interesting and could possibly give me and my team some advice, hence why I posted here. I posted in this section because it is one of the popular sections.

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Overview:

Me and my team is participating the FIRST Robotics 2010 competition. My team has been doing this for only four years (including this year), so we are not veteran (compared to some teams) and not rookies. So anyways, the basic game for this year is: A huge game of Soccer .
You can see the basic idea about this years game here:


If vid above doesn't work: http://www.youtube.com/watch?v=qbA33dX127E

For more information about FIRST Robotics, rules (there's a TON of rules),etc: http://www.usfirst.org/roboticsprograms/frc/default.aspx?=966

Our team is from Chantilly, VA, USA (Westfield High School FCPS) and currently contains about 20 active members, so we aren't a really big team (some teams have like 90 people).
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As of 1/23/2010:


This is the front view of the bot. This is our prototype using the 80-20 10 series (~1x1x1") bars, connectors,etc using last years material. The final chassis will be made out of the same material but will be 2" shorter on length and width. The 20 lbs weights are at the front so we don't flip over the bump in the middle of the field.


The electrical board. Everything is hooked up to a National Instrument's cRIO controller(very top item). Jagwire (the brown things) are used to control the speed of the motor via PWM.


Gear boxes are behind the 120mm fan. The fan was put there because these motors (called CIM motors) get REALLY hot in ~1:30 (each round of the competition is 2:15). That fan moves ~200 CFM and is quite loud lol.


Testing out the scoring mech . This will be a pivoting item with the pushing done by pneumatics instead of hands.

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So folks,

Any ideas? Tips? Interested?

Not sure if I am allowed to post this:
My team needs to get some gears built (4-6) to increase our torque/speed. We have looked a bit locally (CNC) and the prices they ask are ridiculous imo (~$900 in one case). So if any of you can help out with this please post here or PM me.

 

Can you do the torque conversion via mountain bike gears? That would be cheaper.
V-belts and pulleys would also be an option. Anyone with a lathe could make them.

 

Never thought of that. We will look around. Thanks!

 

can you tell some more detail about the push mechanism? it sounds cool, but i don't really understand it.

 

Here you go:

We decided NOT to use just the pneumatics as we will be limited to 60 psi and will not have enough "kick" to hit the ball well.
We started to build the actual drive train today! Yay!

 

ooh i see. is it very accurate? and congrats on the drive train! and how will you do the whole hanging of the tower thing?

 

As for the tower, we are probably not going to do it. However, there is a current discussion about turning our self in to a ramp to allow an alliance robot to go to the platform.

 

Quick update of current status:

We ordered some Plaction (Rough top) wheels from Andy Mark:
http://andymark.biz/plactionwheel.html
This would give us quite a lot more grip when going over the bump. The smooth rubber wheels we are using now slips pretty badly on the carpet that will be used.

Finished most of the final drive train. Tomorrow (and Monday) is a Teacher work day so we don't have school so most of the team will be working from 9-6 tomorrow. Expect more pics tomorrow!

Current ideas:
Due to weight and the limitation of the number of CIM motors (total of 4 on the bot) we may be going with pure pneumatics for the scoring. Currently we are looking at new pistons here: http://www.bimba.com/Products/OriginalLineCylinders/NonRotatingAirCylinders/
Product cat (PDF Warning): http://www.bimba.com/pdf/catalogs/FL_OriginalLine.pdf#page=88

Can any one recommend the bore size we should use? We are thinking a minimum of 2". Also can some one explain advantage/disadvantage of the different piston types (ie Reverse Single Acting, Double acting,etc). Also what is the deal with the bore size and stroke length? How will they affect performance? (ie is shorter stroke with big bore better or the other way around?)

 

If you need any help with the compact RIO, just shout in my direction!

 

^ Thank you. Btw, we are using Java, and the code will be posted up online soon.

 

Worked on new scoring mech today (pics tomorrow!). Works much better than old method. Any one here knows about pneumatics? For example, what's the relation between bore size, stroke length, force, and speed.

 

Final frame is done!

The battery will be mounted in the under side of the bot.

New wheels!

Much better traction!

New prototype for kicking mech!

The old pneumatics method was too slow.

We also have the chain installed but I don't have pic for it. We are also continuing to work on the ramp mechanism.

 

the robots progress

Today after shadow left we completed the drive train and are now able to drive over the ramp on the final design of the robot. We will be starting the ramp mechanism tomorrow and finishing hopefully be next Saturday. I will upload a video tomorrow or Wednesday.

 

school was canceled due to snow today so we will not have pics till next week because school will be closed this weekend 12-20 inches expected

 

^ Can you grab some pics of the work today @ Scott's?

 

i would try a robot that "sucks"a ball in at its back and launches it via spinning wheels out of its front, by adjusting angle of the launch rail and speed of the spinning wheels u can do accurate shots over the whole field, plus by sucking in tha ball at the back u can just steal them from the other robots.

 

^ According to the rules, you can't "suck" in a ball. The ball must always be touching the ground when the robot is controlling/handling the ball.

Good idea though.

 

sorry did not get any pics today but will have some as soon as i can get back over there this weekend. 24-30 inches of snow will suck this weekend :'''(

 

u could accelerate the ball while its still running on the floor and just use an angled plate at the end of the launch rail to give it air.

 

^True.

In any case, the weather in VA really $ucks. We've lost a lot of time and we have only about 3 weeks left. They are predicting 10-20" of snow on Wednesday.