Re: Poll: Turrets for Rebound Rumble
 

Why not both? we were thinking of making a program so our camera sees how far off we are, and makes large changes via drivetrain moving and smaller, precision changes via turret.

Re: Poll: Turrets for Rebound Rumble
 

We're trying to develop a system-un turret, so we could just hit a button for which hoop to aim at, and let the 'bot do the rest. Plus, we think it'd be cool to have TARGET LOCK flash up on the driver's station.:p

Re: Poll: Turrets for Rebound Rumble
 

I think it would be neat to have some lights on the robot that indicate things like "acquiring target" and "target lock"

Just to give the fans something fun to watch.

Re: Poll: Turrets for Rebound Rumble
 

We say "there will be no defense this year" every year. Then there will be the 1729's and the 3467's that will squash your chances of scoring every match.

Re: Poll: Turrets for Rebound Rumble
 

On the other hand, you only have to be touching the key, so the safe zone for a 37" robot with a 14" appendage is approx 8 to 20 feet. Yes, I expect to see at least a few rotating hands and shooters at the end of the appendage. If you think a standard turret is complex, then stay away from this option but kudos to those who try.

Re: Poll: Turrets for Rebound Rumble
 

Well, we have red and blue LED assemblies.
BTW, I'd still like to borrow your o'scope to demonstrate its power to the students.

Re: Poll: Turrets for Rebound Rumble
 

We decided to go with a turret precisely because of the precision required. Without careful design, we've found that most drive trains just have too much lash to be used for precision aiming. When you take the mass of the robot and the floor scrubbing inherent to turning in place into account, you end up having to apply fairly high forces over very small distances. This is not easy with gearmotors and likely to lead to oscillation without careful mechanical and algorithm design.

Its certainly not impossible, but its much easier to use a small, precise gearmotor to turn a lighter turret than it is to try and adjust the whole robot. In general, through Aim High and Lunacy, we found that turrets really aren't all that complicated with a little cleverness. Certainly easier than trying to engineer lash out of a drive train or oscillation out of a PID loop with four independent outputs and inputs.

Re: Poll: Turrets for Rebound Rumble
 

I'd like to hear of any team that did Aim High in '06, making a shooter, tell me that a turret is not necessary.

If teams are going to rely on the driver to aim the robot, I think they'll be in for a rude awakening.

Re: Poll: Turrets for Rebound Rumble
 

We had a static shooter in '06.

We're building a turret this year!

Re: Poll: Turrets for Rebound Rumble
 

My thought is that aiming with the drive base can work, but I think the big advantage of turrets comes into play when you're being actively harassed by a defender. If you can push your way to the key, you're good to go, but if not, or if you want to shoot close-range, a turret will be invaluable against aggressive defense.

Re: Poll: Turrets for Rebound Rumble
 

In Aim High there wasn't a big spot in the middle of the floor that gave you 3 points any time somebody so much as touched you :)

Re: Poll: Turrets for Rebound Rumble
 

Our team started in 2007 so i wasn't around for aim high, but for 2009 we went with a turret because we had moving targets, and so we thought that we needed that ability to be able to track and score on enemy trailers. we soon realised that long-range shooting = very innaccurate and it was easy to simply drive up to the trailers turret facing forward, and score (even with the constant collisions).

This year, we have stationary targets and protected areas on the field. I think turret teams will soon find that the variablity in ball size, shape, mass, density... variability in shooter speed, compression, feed orientation, feed position... will still be difficult to overcome and compensate for even with a slow moving turret.

that is not to say that a turret couldn't help the accuracy of a robot. I simply don't think the benifit is worth the complexity in control, design and programming or the allocation of weight and resources. a turret might add 5% more accuracy to a robot shooting from the key (probably less from closer, more from farther), but in a game where a robot shoots 6 balls a match, going from 65% to 70% accuracy... you still make 4 out of 6 balls.

(this all having been said my team is building a turret, despite my objections.:rolleyes: )

Re: Poll: Turrets for Rebound Rumble
 

I hope you don't think turrets and manual aim are mutually exclusive. We plan on being able to rotate about the center of the robot and use vision tracking to acquire targets. Sure, you can add on a turret system to aid in auto-aim, but you can also build a turret for a manual shooter.

Re: Poll: Turrets for Rebound Rumble
 

Has anyone devoted any thought to having a limited-traverse mechanism capable of aiming maybe 20 or 30 degrees or so to get precise aim, instead of a fixed shooter or a fully rotating turret? You could still make accurate shots but it would be a simpler design.

We had a turret in 06 and decided that it was better to do a fixed shooter this year.

Re: Poll: Turrets for Rebound Rumble
 

Ours is designed for about 45 degrees rotation, as we figured that's about all it needs.