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.