[MCC] Minimum Competitive Concept 2012
 

Each year I am amazed by what teams come up with to compete in FRC. Teams have a ton of wonderful ideas and some even see good execution of those ideas.
I would like this thread to focus on the "Minimum Competitive Concept" for a robot for 2012. It is often easy to identify all the possible tasks you could have a robot do. Prioritizing those tasks, and realizing it in the form of a competitive robot is in my opinion much more impressive.

If you haven't read the Simbotics Strategy Presentation, please do before responding to this thread. Especially review the "Golden Rules 1&2".

Assumptions are that one of the priamry goals of the MCC is to play in elims (not necessarily win on Einstein), and you team has mid-pack to lower fabrication resources.
Please list your assumptions, strategy to seed high, estimate of a winning score, and what robot design elements would achieve this score.

I will throw my $0.02 in later.

Re: [MCC] Minimum Competitive Concept 2012
 

My match strategy priorities would be sorted by highest (estimated) points-per-second value, in that each discreet objective takes X time and nets N points. It doesn't take repetition within a single match into account, but does assume consistency between matches.

I'll also add that every team should lay out ALL stretch objectives, how to meet ALL objectives and then decide how much they can accomplish in a given season. Teams often grossly underestimate how much time it takes to build something, which is the root cause of why their robots do not work properly on the field.

Strategy to seed high: Autonomous points + Coopertition points. If at least 8 points can be achieved consistently in autonomous and Coopertition points achieved in most matches, then the rules of the ranking system put the achieving team higher than those who do only one or the other (given the same win/loss/tie record).

Minimum Objectives to meed the High-Seed Strategy

• Minimum objectives to net autonomous points: 2 balls go into a basket.
• Minimum objectives to net coopertition points: Bot gets onto the coopertition bridge via driving.
• Robot can also minimize opponents' teleop points by blocking the inbounder lane as best as possible (realized at first competition)

If achieved each match, average contributing score is 8-12 points + 2 coopertition points. In hindsight, that wasn't enough for a win in an average match (depending on which week is played) yet that WAS enough for a seed higher than 8 at most Regionals, given an equal win/loss ratio. These are particularly true of Regionals in which there were relatively few teams (30-50) in the first few weeks.

Stretch Objectives for higher effectiveness, in order of highest to lowest priority:

1. Robot lowers the coopertition bridge
2. Robot drives onto coopertition bridge after it is lowered
3. Robot gets 2 balls in autonomous into at least the middle basket. Driving straight may be required, depending on the mechanism.
4. Robot is able to collect balls and deliver them to the mechanisms that scored the 2 autonomous points, in order to potentially score some teleop points
5. Given #1 and #4 in this list, traversal of the field and active delivery of balls also becomes a realized strategy
6. Given #4 in this list, the robot may also reverse the intake to feed another robot in autonomous also becomes a realized strategy

Assumptions
From here we will assume that the robot will perform stretch objectives 1-3, given only a drill press, band saw, hand tools, the KOP, no automated machining support and a ~$1000 budget. We'll assume moderate quality with the hand tools (i.e. the students actually do measure twice/cut once). We'll also assume no CAD on the robot :ahh: .

There may be some extra cost/time associated with individual mechanisms for each team, yet I reduce that down to each team's knowledge about materials and their own capabilities. This is how I would estimate it given the assumptions above, what I personally know about materials, and what I know about time for 3-4 students on my team to prototype & build the mechanisms.

Drive Train
2-CIMs through CIMple Box transmissions, default gear ratio. Configuration is a 4WD wide-drive with default KOP wheels. Victors/Jags are in 'brake' mode.
Satisfies: Stretch Objective #2.
Cost: $0.00
Time to Build: 6 hours. Could be done by the end of Day 2 depending on how much strategy happens, and it's only done so early so that there is something to mount other things to right away.

Bridge Lowering Mechanism
2 arms that are linked together in the middle via a cross bar. At the ends, the arms have a passive angled inverse-ramp. Powered by 2 KOP window motors via 2 Spikes. Mounted via the Igus rods/bearings. The leverage on the rotating provides the majority of the downward force in most situations,
Satisfies: Stretch Objective #1
Cost: ~$150 for 2 spikes, some 3/4" plywood, some sandpaper, a small 1/16" Teflon sheet, some glue, 2 #35 48T sprockets, 2 12T #35 sprockets. There should also be some left over for 2-4 limit switches.
Time to Build: 24 hours (1-2 weeks depending on how often a team is allowed to meet)

Autonomous Scoring Mechanism
A single-sided shooter wheel utilizing the remaining KOP wheels, 1 CIM motor, and a $15 AM CIM hub. Wheel is positioned relative to the front of the robot such that it allows room for the bridge lowering device, and is positioned at roughly the maximum allowed height. If its gravity fed, the wheels are on the top, putting a forward spin on the ball. If the feeding mechanism is used, the wheel is on the bottom putting a backspin on the ball. For manufacturing, the wheels are spun on a drill, and using a chisel the nubs of the tread are cut off such that the wheel becomes ~5.5" diameter and has a smooth tread finish. Assume a 45-degree fixed launch angle. Using the $30 Banebots voucher, 1 RS-550 is affixed to the rotating shaft such that its back EMF current can be utilized as a speed sensor on an analog port. The max amount of Banebot RS-550's is purchased on the vouchers since they might also be used in future years.
Satisfies: Stretch Objective #3 & #5.
Cost: ~$350 for wiring, Jags/Victors, 1 CIM motor, framing, mounting structure, nuts/bolts, shaft & adapter for the BB550. May be offset via FIRST Choice.
Time to Build: 20-30 hours (1-3 weeks, depending on how often the team meets)

Ball Gathering Mechanism
Premise: A single conveyor feeds directly from the ground to the spinning wheel. The conveyor is single-sided and has guide rails, with ~1" compression.
Materials: Hollow round Urethane belts from McMaster, some 1.5-2" PVC pipe, strips of rubber (keeps the belts inline), glue (keeps the rubber on), steel axles from Lowes (or wherever), 1 CIM motor, 2 AM hubs as shaft adapters (from CIM to the steel axles), some 1" Aluminum tubing and some plywood for framing & structure (also from Lowes... or wherever), 1 Victor/Jag, some wiring, 4 pillow blocks that allow for misaligment
Satisfies: Stretch Objective #4, #5, & #6.
Cost: ~$350 -- may be offset somewhat via FIRST Choice
Time to Build: ~20 hours (1-2 weeks, depending on how often the team meets)

Programming:
The programmers would need diligence and a methodical approach to calibrating autonomous. We were able to sit on a corner of the key and get >90% accuracy after calibration at championships, so it's definitely possible. They'd also need to calibrate the conveyor speed.

Re: [MCC] Minimum Competitive Concept 2012
 

While reading the OP, I immediately thought of team 2781 (we played with and against them at Midwest). They weren't able to do much, but what they could do, they did really well.

Here is what they would do pretty much every match:
1) During autonomous, they drive forward to the fender and drop both of their balls into the bottom basket. 8 points guaranteed every match.
2) Play defense. They weren't able to pick up basketballs from the ground, but that didn't stop them from helping out their alliance during tele-op. They played solid defense.
3) Bridge balance. This, again, is something they could do very well. They co-op balanced in 8 of their 11 matches.

They ended up 6-5 with a qualification score of 28. This was enough to put them in the 7 spot, guaranteeing them a spot in eliminations. After all was said and done, they ended up as the 4th alliance captain, and picked us and 2709.

We ended up winning in the quarterfinals, 45-15, and 36-14. Though, we ended up losing to 16, 148, and 2022 in the semifinals (gave them a couple of good matches).

Long story short, you don't have to do everything to be competitive in FRC. As long as you can do 1 or 2 things very well, you can be fairly competitive.

Re: [MCC] Minimum Competitive Concept 2012
 

I think the following is the simplest way to seed in the top 8 (not necessarily in the top 4). If it wants to do well in eliminations or be picked by another alliance, it will have to add at least one more capability.

Capabilities:

Bridge balancing
• Tip the bridge down for yourself
• Tip the bridge down to let another robot onto a bridge from the same side
• Tip the bridge up to let another robot onto the bridge from the opposite side, or to dislodge balls under a bridge.
• Push another robot with a weak drive up the bridge
Use PG71 Gearmotor, some AndyMark parts, and an arm to push the bridge. Gear motor with 4:1 reduction pushes the bridge down easily. Our first arm was simple to make and worked well.

In addition to the 2 CP these abilities can net you, they also make it possible to assist alliance partners onto the bridge for 10 or 20 balancing points. This was an underutilized strategy, in my opinion. Lots of robots lacked a good bridge manipulator but had a good enough drive to climb and balance.

Barrier traversal
Use the simplest drive that can get over the barrier. I’m thinking long 8WD using 8” wheels and angled skids on the front end.
This capability significantly improves the odds of bridge success. It provides Plan B in case balls get stuck under bridges or a robot tips on one side of a bridge. It also allows you to pop over the barrier and help the opponent onto the Co-op bridge if their bridge manipulator is failing to get the job done. Also, it allows the robot to cross to the other side to sit underneath a bridge to stabilize it while a robot or two balances to speed up the process.

Gathering
None.

Scoring
• Dump 2 balls into low goal in hybrid mode.
Device consists of a space to preload two balls plus an actuator to let them roll out into the low goal.
In Hybrid, the robot would need to drive forward, stop, and dump. Ideally the programmers would have also write a more complex autonomous mode where the robot lines up in the corner of the key.

Autonomous scoring: 8 pts

Match Strategy
1) Score 8 points in Hybrid.
2) Help allies double balance by any means necessary.
3) Balance on co-op bridge.
Strategy changes if an ally has a weak drive that is unable to climb, and the other ally can’t push them up. One possibility: let the better of the allies do co-op bridge and push the weak ally onto alliance bridge to balance (possibly having other ally under bridge for stabilizing). If an ally is a good scorer, the strategy might also change away from double balancing, but that’s okay if it results in a higher expected score.

The goal is to get 28 points as often as possible from Hybrid + balancing. That wins quite a bit of the time, especially at average to weak events. Combined with consistent coopertition balancing, that will result in good seeding if pulled off consistently.

Overall
Everything on this robot is setup for balancing. The lack of a tall shooter makes it easier to keep the center of gravity low, even if 8” wheels make it harder. The drive would be geared quite slow. Maybe 6 FPS. Example: use 12.76:1 Toughboxes with a 26:12 reduction. It is important to have nice fine control for balancing, and it is important to have torque for climbing and pushing while climbing. Speed is not important for this robot.

Upgrades
If a team built this robot and finished early, looking into a collector that can grab basketballs (even one at a time) and dump them over the barrier could make it an attractive second pick. Adding a brake for 1 CP on unbalanced co-op bridge is also a good upgrade.

This might be on the edge of MCC, and that was my goal. Removing gathering and shooting takes out a LOT of complexity, and the bridge is more important than shooting in qualifier matches at an average Rebound Rumble competition.

Re: [MCC] Minimum Competitive Concept 2012
 

IMO, The design of the MCC should focus more on being a viable second or even first round pick than seeding high. I think seeding high relies on too many variables. Therefore, i think it should have:
A wide frame to make yourself a more favorable second pick. I noticed that there was a huge demand for wide bots as second picks at the events I attended.
A one point dump auto because 8 pts per match guaranteed looks good and helps seeding.
A bridge manipulator on the back because the bots with coop autons were in even higher demand than the wide bots. Even if the auto was 'Feed and drive back to bridge', you would almost be insured a slot playing Saturday afternoon.

I think this design would be a very valuable second (or even first) pick at most events.
If possible, I would add:
Collector to feed the shooters on your alliance
Bump crossing to get to the side you will be defending faster
2 point dump capibilities because 12 pts per match is better than 8.
Brakes for easier balancing and 1 cp almost guaranteed
In that order.

Strategy would be to get your auto points however possible, play defense either at the fender or the spot where the inbounder is bouncing balls across the bump, and then head to the bridge (preferably coop).

Re: [MCC] Minimum Competitive Concept 2012
 

I have a question for all of you "low goal dump in auto" guys. Which is simpler to build & program for autonomous: a robot that sits in place and launches 2 balls at the basket via a single control loop, or a robot that moves towards the basket (presumably in a straight line ... oh wait) and then dumps?

Now the same question, without knowing about the ball inconsistencies?

Now the same question, with a team who will do what it takes to tweak, hone-in, and otherwise calibrate to mitigate the ball inconsistencies?

Re: [MCC] Minimum Competitive Concept 2012
 

I agree with you that it is easier to program a bot to just sit there and shoot than to drive up to the fender and shoot. However, it takes a much more powerful shooter as well as a more precise shot. IMO, it is easier overall to drive up and shoot.

Re: [MCC] Minimum Competitive Concept 2012
 

In my opinion, the following were this year's essential tasks:

• Floor pickup / reverse
• Cross bridges by self (i.e. can lower bridge and drive on)
• Score in a goal at the fender. (2 point goal?)

1 point or 2 point - In my opinion / observation, it is not that much harder to score in the 2 point goal than it is to score in the 1 point goal. So while I am not sure if it is essential, I would suggest a team go for it as I don't think there is much of any opportunity cost. The autonomous gain of shooting for the higher goal isn't that much (25% more points) but in teleop it's twice as many points per ball which is too big of a margin to ignore unless it is significantly harder to achieve. Which I don't think it is.

Then again, a 20 point contribution to the match alone (low goal in auto + 2 balls on bridge + single balance) is probably significant enough to be competitive at many events this year. Maybe the 2 point goal isn't so important...

In auton, a drive forward and shoot routine is pretty doable. Driving 12 feet straight(ish) is not unfathomable, and the fender itself helps the drive base square up. The 10 points here are somewhat easy to get, if you design for it in particular rather than a more general shooter.

I don't think crossing the bump is mandatory, and I think the other criteria cover most of the other roles the robot could play at higher roles. Having floor pickup and reversal allows for feeding a higher power auton, playing ball starvation defensive strategies, etc. in a match where the robot is the least good scorer. Being able to lower the bridge is important for those easy 10 points and also allows the robot full field mobility.

Scoring 20+ points a match and being able to co-op bridge is probably plenty to seed high at many events. I haven't run the numbers though.

I didn't include anything about orientation, but I think building a robot longer than 28 inches with such simple goals would only limit the robot rather than help it.

In my mind, 4334 is the epitome of the minimum competitive concept. I don't know how reliable their auton is, but they did an awesome job doing the mandatory parts of the game well, and proved themselves as an Einstein worthy asset to an alliance.

Re: [MCC] Minimum Competitive Concept 2012
 

I'm not sure how effectively they did it in competition, but at champs i saw 4334 running a low goal auto on the practice field very consistently.

Re: [MCC] Minimum Competitive Concept 2012
 

Team 61 comes to mind this year when it comes to an extremely basic yet effective robot. Pretty much it was a tank drive robot with a low goal dumper and a good bridge mechanism. While I don't have the scouting data for each match we did play with them once at GSR and then again this past weekend at Battlecry. In auton they would drive forward and dump their two into the low goal (8pts). They actually preferred not to score in teleop because they viewed their 1points shots better served doing defense/feeding over the bump then focusing on a double balance or co-op. Overall they were extremely successful and in our match with them at GSR between our two autonomous modes we pretty much had the match won once they hopped up onto the bridge in the first few seconds (51pts when the round ended!). They finished GSR with a record of 7-3!

My minimum competitive concept is very similar. It would essentially be a basic 4wd wide robot with a dumper, basic off the floor pickup, human fed (elevator from the pickup goes straight up to a roller that can also be loaded from a slanted hopper), and a bridge mechanism.

Basic strategy would be to drive to the fender and dump the two balls in auto (8pts) or A-bomb to another robot, knock the balls of the co-op & alliance bridge once teleop begins, cross the bridge, play defense, pickup balls from the floor to return over the bump, load balls from inbounder and return over the bump, and then balance on the co-op or double balance with an alliance member (20pts).

Overall you are only scoring 8pts-20pts a match but you offer so much to an alliance in eliminations between a triple balance, feeding, and autonomous.

EDIT: As to dumping vs shooting in auto they are both challenging. Shooting from the key would require a shooter of some sort which would need to take into account ball in consistency as well as accuracy. Dumping on the other hand entails a smaller mechanical challenge with a programming challenge. Assuming your robot drives relatively straight it wouldn't be too hard to make a program that drives straight to the fender before dumping the two balls. Or you utilize the kinect and let your human player practice lining it up.

Re: [MCC] Minimum Competitive Concept 2012
 

This is great discussion, and I really appreciate folks calling out specific examples of teams that executed a solid plan and had strong performance to back it up.

My MCC for 2012 was more simple than most here. In fact it is simple enough I can CAD it right here:
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O O

This little robot is a wide 4WD with large enough wheels and high enough bumpers to plow over the barrier and would likely use about 8" pneumatic tires. The sides are plywood, and the first half of the side profile is flat and att approximately 10" height. The second half is at 45 degrees incline. On the flat section would be a couple of small depressions to set 2 balls during hybrid just to get them off the bridge.

While initially this appears to just be a BOW (box on wheels), it is a very tactical box on wheels. Assuming 0 offensive capability in the alliance, the MCC would cross the barrier and tilt the alliance bridge towards its home side to clear the balls and prep it for the 2 partners to climb the bridge. Once they are on, you back up until just the flat will engage the bridge and have your partners drive forward until it catches them. At 10" you get it very nearly level, close enough for your teammates to make minor tweaks, and the support keeps the robots from Charlie-Browning. 20 pts. 20 pts. was higher than the average score at most events (only a couple of teh 50+ regionals averaged higher than 20 pts./alliance). The average (this includes winning scores as well), thus you would be able to win a majority (though not all) matches this way.
The MCC would then prep the CoOp bridge and hopefully Co-Op almost every match.
How do I know this would work? Not only does the math look good, but at Kettering there was a software issue with the speed control on our shooter which rendered it all but useless for most matches. And we executed this exact strategy. While our robot was far from an MCC, it had the same features built into it, and those were the features we used with a great deal of success in qualifying at that event.

Initially I wasn't thrilled with this concept as I believed it required a partner to do the bridge. Later I learned by watching very similar robots to this concept that you could tilt the bridge and catch it on the rebound if you timed it just right.

This is not a design that would likely win Einstein, but it is one that had a lot of potential to do well at District and regional events. Because it isn't trying to do too much, it would get very good at what it does.

Other roles that it can play when there is good offense on its alliance:
Inbounder alley blocking (between bridges)
Fender Defense
Opponent scavenger blocking (between bridges)
Middle bot for the 40 pt. triple balance in elims.

Re: [MCC] Minimum Competitive Concept 2012
 

I agree with much of this. If I was going for the most attractive 2nd pick, I'd simplify a bit. Brakes are unnecessary since you aren't trying to seed well. Autonomous shooting and dumping are unnecessary since you aren't trying to seed well. Those functions are unnecessary for success in eliminations as a defender / gatherer robot / balancing robot. In fact, it is to your disadvantage to seed too high and become an alliance captain if you are trying to be the ideal second pick. Instead of shooting ability, simply make sure the gatherer can reverse and feed two balls to a shooting robot during Hybrid.

As has been stated, 4334 was smart enough to pull this off, and the proof is in the pudding. Kudos to that team for a really smart strategy for the year.

I think it's fascinating to try to figure out how to be the elusive 2nd pick of the #1 or #2 alliance. It's tricky and requires some luck, but I think this was a better year to try it than most.

Re: [MCC] Minimum Competitive Concept 2012
 

I won't use the word "mandatory," but crossing the barrier is a low cost / high benefit capability for a robot that is banking on bridge success as the cornerstone of its strategy. I think deleting that capability would reduce the percentage success rate of alliance and co-op bridge balancing below the threshold of "competitive."

Re: [MCC] Minimum Competitive Concept 2012
 

Ike, how would this robot seed high? It would be (at best) middle-of-the-pack when it came to autonomous score, thus not be near the top of the rank of robots with identical coopertition/win points. There are several instances where teams had 'lucky' schedules this year, yet when making design decisions in Build Week 1 a team doesn't know that schedule. So I think that this robot would compete and be luckily competitive rather than competitive no matter what.

Re: [MCC] Minimum Competitive Concept 2012
 

I can show you several with this basic strategy that seeded quite high. Focusing effort on a low effort high return scoring element like balancing tended to have higher average scoring capability than running around picking up balls and randomly throwing them at the back board. This gets you above average wins which will/should get you well into the top 20 of a 40 team event. Teams that put extra focus on the Co-Op this year were more successful with the Co-Op plain and simple. Many teams early in the season waited until the last 20 seconds to Co-Op and failed. Many good teams in Michigan gave it a full 60 to 45 seconds, and had a dramatically higher success ratio. This was true of later events elsewhere. By not having the distraction of doing anything with the balls, it this concept will get very good at the things it does well.
Yes, you will have a lower than average HP score which is the second criteria, but you will have above average Wins, and well above average Co-Op points.

The key to this strategy is the assumption that others will not follow Simbots Golden Rule #2. That one says basically it is better to be really good at 3 things than it is to be mediocre or worse at 5 or 6 things.
The other key to this strategy is that allow you will "finish" early, you will use the extra time to develop your drivers. Most teams give their drivers less than an hour or two of drive time before their first competition. Many have never driven the robot as it is still being put together and code being added. If your drivers have an extra week of driving and concentrated practice, they will be better than half the field.

In theory if a high enough percentage of teams listen to this advice, then it would no longer become good advice and teams would need to add features. It has been my experience that many teams will appluad the concept of MCC. Give it as advice to others, and then do the opposite (my own team included on most occasions). Some will do better with a more complicated concept. Most will not.