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-   -   [DFTF] Budgeting for a Competitive Robot... (http://www.chiefdelphi.com/forums/showthread.php?t=98775)

Nemo 12-12-2011 18:05

Re: [DFTF] Budgeting for a Competitive Robot...
 
Here is a shot at some of the costs you are asking about. Here are my assumptions:
  • Use kit transmission, whatever it ends up being
  • Use 12T (or whatever) sprockets from kit
  • Not using 22T (or whatever) wheel sprockets from kit; likely will need to purchase new ones that give the desired gear ratio
  • Upgrade kit wheels to plaction wheels
  • Use 4 Jaguars for controlling manipulators
  • Buy 4 Victors to control 4 CIMs in drive
  • Use Kit frame with dead axles
  • Use 1 Fisher-Price motor + gearbox from KoP
  • Use 1 Denso motor from KoP
  • Buy 2 RS-550 manipulator motors using Banebot planetary gearboxes
  • 1 pneumatic manipulator: use Festo solenoid from KoP if provided, use Bimba free cylinder order if provided

$156: 6x 4" plaction wheel (6" FIRST wheels can be had for $7 each)
$60: 12x 3/8" ID 1.125" OD bearing
$96: 8x Sprocket
$50: 2x CIM motor
$360: 4x Victor controller
$28: 4x 40 Amp fuse for PD board
$15: 6' of 3/8" sch 80 pipe for axle spacers (is what AndyMark uses)
$129: 2x Banebot P60 64:1 gearbox
$15: 2x RS-550 motor
$24: 2x pool noodle set
$20: 3/4" x 24" x 48" Plywood for bumpers
$54: 4 yards of bumper fabric from Seattle Fabrics

That adds up to not quite $1000. Shipping for that would be something like $50-100 if you ship ground and combine orders. (ground shipping is fast with AndyMark) If you want a spare Jaguar, spare Banebot planetary gearbox, and a couple of spare motors, that is another $175-200.

I'm not brave enough to speculate on the cost of other assorted mechanical materials for actuators, but those costs seem to add up quickly for our team.

I think $1500 is just about as low as you can go for 4 CIM 6WD with any sort solid manipulator.

theprgramerdude 12-12-2011 18:26

Re: [DFTF] Budgeting for a Competitive Robot...
 
We rarely spend more than $1000 a year on the robot. The main reasons being, A. we can salvage a lot of extra electronics and drivetrain items off of past robots or old KoPs that we never used, and, a big one,
B. We get a ton of items donated. Usually, each year we get around $500 + worth of Polycarbonate and aluminum donated from a local manufacturing company. This is mainly what we used to then build the rest of chassis on top of the KoP chassis, as our coach preferred to save money wherever possible.

If you don't think starting off with the KoP chassis is the best idea (I didn't my senior year, but we didn't have the means to not use it), but do have the means (manufacturing technology) to not use it, then I'd certainly try to go out and get a bunch of raw material donated like we did, and use that to make your robot with, rather than purchasing much more expensive COTS items like the pre-made KoP chassis.

Billfred 12-12-2011 19:30

Re: [DFTF] Budgeting for a Competitive Robot...
 
I don't have the breakdown, but I recall 2815 spending around $1,000 on last year's robot. (Despite our success on the field, the robot was average at best; you being you, you would be able to take chicken soup and make it fine dining.)

If you've got a few materials already, you'll be okay. While more is always better, these days a team can have a good season from the kit, the Lowe's hardware aisle, and a couple things from AndyMark or McMaster-Carr.

Joe Johnson 13-12-2011 12:20

Re: [DFTF] Budgeting for a Competitive Robot...
 
I am surprised at how low the numbers are really.

If you think about it, every actuator (whether pneumatic or motor) is going to run close to $200 by the time add in all the associated costs.

I suppose that teams have 5-10 actuators all in (not counting wheels as actuators) that $1K-$2K right there.

How are folks doing full up robots for so little?

Joe J.

Mk.32 13-12-2011 13:01

Re: [DFTF] Budgeting for a Competitive Robot...
 
We were under $1000 this year as a rookie team.
Using just about everything we could from the KOP. We used the kit frame and our lift was just alum sliders and wood. With Brackets for the pneumatic ram (free from bimba) were made out of REM alum we got from the local metal shop, about $2.
It doesn't take much to make a mount for a cylinder or a bracket for a motor.

Though our robot wasn't really that great, it had a good run in off season.
The real cost comes in from prototyping and breaking stuff....

Alan Anderson 13-12-2011 13:43

Re: [DFTF] Budgeting for a Competitive Robot...
 
Quote:

Originally Posted by Joe Johnson (Post 1090840)
I suppose that teams have 5-10 actuators all in (not counting wheels as actuators) that $1K-$2K right there.

How are folks doing full up robots for so little?

Motors are in the Kit of Parts. Pneumatic cylinders have been donated by Bimba in recent years. I think the biggest cost to many teams is likely to be speed controllers.

Mk.32 13-12-2011 13:46

Re: [DFTF] Budgeting for a Competitive Robot...
 
And gearboxes...
Last year rookie kit you got 4 jaqs + 1 victor. So you only need to add another victor or two.

IKE 13-12-2011 13:58

Re: [DFTF] Budgeting for a Competitive Robot...
 
Quote:

Originally Posted by Joe Johnson (Post 1090484)
Budgeting for a Competitive Robot...

Can you define competitive? This can vary the costs considerably.

theprgramerdude 13-12-2011 14:01

Re: [DFTF] Budgeting for a Competitive Robot...
 
Quote:

Originally Posted by Alan Anderson (Post 1090862)
Motors are in the Kit of Parts. Pneumatic cylinders have been donated by Bimba in recent years. I think the biggest cost to many teams is likely to be speed controllers.

Plus, most of us have the ability to re-use last years components, so that usually means a few hundred-$1000 in savings per year.

Kimmeh 13-12-2011 14:04

Re: [DFTF] Budgeting for a Competitive Robot...
 
Quote:

Originally Posted by Joe Johnson (Post 1090840)
How are folks doing full up robots for so little?

Magic. And donations. But the largest reason is because that's their only option.

I can't give you specific numbers (because I don't remember them) but my team frequently builds a robot well under the perceived "average cost". While we may not have the most competitive robot, that's nothing that a few iterations more wouldn't cure, not more money.

Billfred 13-12-2011 21:09

Re: [DFTF] Budgeting for a Competitive Robot...
 
Quote:

Originally Posted by Alan Anderson (Post 1090862)
Motors are in the Kit of Parts. Pneumatic cylinders have been donated by Bimba in recent years. I think the biggest cost to many teams is likely to be speed controllers.

...which we always yank off an older robot we've mothballed because it lacked a control system.

ayeckley 13-12-2011 21:47

Re: [DFTF] Budgeting for a Competitive Robot...
 
Quote:

Originally Posted by Joe Johnson (Post 1090840)
If you think about it, every actuator (whether pneumatic or motor) is going to run close to $200 by the time add in all the associated costs.

From a pneumatics perspective, I think that estimate is a bit on the high side. I'm sure you *could* spend that much, but with a modest amount of pre-season planning that number can be brought down dramatically. As a re-rookie some of this won't apply to your situation, but within a year or two your team should be able to reduce your costs by using some of our tactics:

1. Always take Bimba up on the max donation each year, even if you have no plans to use all (or any) of the items. Obviously the strategy is to get the broadest possible range of items to ensure that a *nearly optimum* selection of cylinders is "in stock" for your team down the road.

2. eBay. In the offseason I periodically scrounge parts for bargain-basement prices, and we don't shy away from used items when appropriate. We've bought used cylinders, solenoid valves, etc. and new fittings, etc. for less than 50% of the retail price. Obviously the BOM accounting has to be at full new price, but there's nothing wrong with the robot actually costing less than it does on paper. The loosening of the pneumatics rules in the last couple of years makes this a viable option, and we are careful to purchase items with a long product lifecycle to ensure that we aren't designing-in obsolete products. In our case, we've got dozens of FRC-legal SMC solenoid valves (of all varieties) which will last us for many years and we spent less than $200 acquiring the whole selection.

3. Strategic use of First Choice. For example, IIRC one of the options last year was a pneumatic fitting assortment. There were enough fittings in there to last us for several years.

4. Inventory management. If someone takes charge of the unused KOP items, excess purchased parts, etc. in the offseason to prevent loss then this is a huge cost savings. It almost sounds like some of the posters on this thread are starting with zero parts left over from previous years. Where did all of the extra parts go?

5. Damage prevention. I explain to our students that this stuff is expensive. It's totally OK if it breaks during the heat of competition, but let's not waste our hardware (and our sponsors funding) unnecessarily by horsing around, etc.

Chris is me 13-12-2011 22:14

Re: [DFTF] Budgeting for a Competitive Robot...
 
Quote:

Originally Posted by ayeckley (Post 1091005)
It almost sounds like some of the posters on this thread are starting with zero parts left over from previous years. Where did all of the extra parts go?

Considering the OP is starting a rookie team, I think assuming that they have nothing is probably a good idea.

ayeckley 14-12-2011 07:42

Re: [DFTF] Budgeting for a Competitive Robot...
 
Quote:

Originally Posted by Chris is me (Post 1091016)
Considering the OP is starting a rookie team, I think assuming that they have nothing is probably a good idea.

I understand Joe's situation; I'm referring to the veterans that describe spending more to build their robot each year than is intuitive to me. Perhaps I'm expecting everyone to be as thrifty as we are (out of necessity).

Joe Johnson 14-12-2011 09:09

Re: [DFTF] Budgeting for a Competitive Robot...
 
Quote:

Originally Posted by IKE (Post 1090864)
Can you define competitive? This can vary the costs considerably.

This is pretty straightforward for me.

A competitive robot is one that is virtually always playing in the elims and, moreover, is drafted in the first round in more often than not*.


Caveats:
  • FIRST isn't about building robots. I know. But I also know that Inspiration comes in a lot of flavors and I, for one, believe it is a lot easier to inspire my kids when we set "playing after lunch on Saturday" as a worthy team goal.
  • There is more to making a competitive team than building a competitive robot, but there is a minimum level of robot performance that will meet the above standard.
  • Of course there are competitive robots that fall through the cracks. But I am talking about a statistical idea, a sort of thought experiment: imagine that the same regional were run 100 times in 100 parallel universes, a competitive robot would be drafted or drafting 95+% of the time and, if not a drafting team, drafted in the top 8 50+% of the time.
Joe J.

*assuming the associated team is not full of jerks, the drivers are reasonably competent, ... It is easier than you'd think to get yourself crossed off a draft list. I advise my teams, "Be the team you'd want to partner with."


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