Team 73 Defensive Bot (Almost There)
 

Here's a pic of our 2012 bot. It is almost done, we just have to install chain on one of the wheels, add a kill switch, and a curtain to the front of the bot to help us retain balls.

Our team builds two different bots every year one offensive, one defensive to see which one is better. We haven't decided which one we are going to use.

This bot is a blocker bot so it means we will be trying to stay in front of teams that will be shooting from low to the ground and attempting to catch their balls. We can also catch rebounds as we have an open top. We have an on-board shooter so it means we will be able to catch balls and shoot them across the field for our alliance members to pic up and shoot.

We started working on this bot about 10 days ago. Tell me what you think?

Re: Team 73 Defensive Bot (Almost There)
 

Personally, I don't like mecanums.

But besides that...my god is this a good idea for a robot. Without even seeing your other bot, I'd say go with this one. There are gonna be a lot of shooter bots that are only accurate from the key that need to be fed, and you gotta feed em!

If you don't seed first with this robot, there is a good chance you will be pick #1.

Re: Team 73 Defensive Bot (Almost There)
 

Mecanums on defense? It does not seem ideal to me. Other than that, it is a very nice defensive design. I like it very much.

Re: Team 73 Defensive Bot (Almost There)
 

Our strategy is not push people around but to stay in front of them or just get on the opposing team's nerves. So the mechanums will give us manueverability to do that.

Re: Team 73 Defensive Bot (Almost There)
 

I agree with 73 in the fact that mechanums are actually a good idea for this defensive robot. As we've seen in the past, typical brute force FIRST defense doesn't always work out too well with safe zones. There will be a time and (very few) places for the brute strength to be brought out. I think for this "goaltending" robot, you'll want as much, if not more, maneuverability than the offense.

Great robot design. It can obviously be countered by a higher positioned shooter or shooting from the fender, but I think you're gonna get on a lot of teams nerves. Just make sure your drivers get a LOT of practice driving with this robot close to the fender.

Re: Team 73 Defensive Bot (Almost There)
 

I see this robot as sitting in front of the fender strafing back and forth trying to distract teams and hopefully get some rebounds off of missed shots, and then firing them back to the other side of the field. With them up against the fender they will limit teams who can only score while touching the fender...

Re: Team 73 Defensive Bot (Almost There)
 

I would recommend making a slot in the back so the human players can feed your hopper so you can clear balls.

To be able to play defense you need to first cross over to the other side of the field... Can this robot do that?

Re: Team 73 Defensive Bot (Almost There)
 

It's always fun to see robots who take "alternate" game approaches.

One suggestion I would make is to add some sort of a gate at the bottom of your catching hopper so that the balls dont necessarily start firing as soon as one drops in. That way your not collecting a blocked shot only to bury it right back into the other team.

Good luck.

-Brando

Re: Team 73 Defensive Bot (Almost There)
 

IMO you have a significant flaw in this design. The blocker should be as far over to the side of robots that you are blocking as possible and sloping down away from that to feed your return mechanism. The way you have it the shooters can gain height across your entire robot before hitting the barrier on your robot. This will allow a large number of robots to shoot right over you.

Good offensive robots will be designed so that the ball leaves the robot's frame/bumper perimeter at a height over 60" so that this strategy won't work against them, but from the posted designs so far this will have some success.

Also is it possible that alliances can shoot more than 3 balls in your robot before you clear them? You make an easier target than the baskets. Yes I know this not in the spirit of the rules but technically you can concievably rack up penalties and it will appear to be your fault depending on the referees/circumstances.

Re: Team 73 Defensive Bot (Almost There)
 

Thanks for the input. I think adding a slot is a good idea.

We can crossover the bump, but we need teamwork (or coopertition) to get onto the bridge as we have no way of manipulating it.

Re: Team 73 Defensive Bot (Almost There)
 

Thanks Brando! We were considering methods to reduce the likelihood of 'face smacking' opponents with balls. Due to time we may just have to stop the shooter or run it in reverse until we are ready to fire. If we had more time a gate would be the way to go!

Re: Team 73 Defensive Bot (Almost There)
 

It's an interesting concept, but I'm not sure the dynamics of the game will work out the way you think it will. If I'm on the key and you're in front of me, I'll simply back up and dare you to follow.

Re: Team 73 Defensive Bot (Almost There)
 

If you run a bar across the top front of your hopper and place a net on top you can prevent robots from shooting through you by forcing them to shoot into a ceiling. If the netting is loose enough, angled down and back, and has an opening in the back section of it, it won't prevent you from getting rebounds either. Balls could still be rebounded when they hit the top of you. The loose netting would cut back on their bounce as well as give you a larger collection area up top (with no top, the balls could go through you on the rebound just as they could on the original shot). Just make sure you don't cause a ball jam up there.

Re: Team 73 Defensive Bot (Almost There)
 

We have accounted for this. We are going to run a bar across the top portion and hang a clear plastic shower curtain from it. The idea is that the ball will get trapped in the shower curtain and fall into our hopper. We want to keep the top open for catching rebounds. The curtain will also stop rebounds from bouncing out of our bot. I will post more pics tomorrow after we have installed the curtain.

Re: Team 73 Defensive Bot (Almost There)
 

My thought as well, and to build on that...while sitting in the key, most tall shooters are arching the ball well over the 60" height of a defensive robot.

Would be curious to see this up against a low/mod scorer and or fender bots.

Re: Team 73 Defensive Bot (Almost There)
 

I agree. Being baited into the will be tough for our drivers. But how will you deal with your alliance members clogging up the key with us in front of them.

Re: Team 73 Defensive Bot (Almost There)
 

I think this thread needs a reminder that there's no h in mecanum. ;)

Re: Team 73 Defensive Bot (Almost There)
 

If anything, you should try to contain balls and starve opponents because, as other teams have pointed out, we are going to stay in the key for most of the game, and the rest of the game is grabbing balls. Focus on the latter, and ensuring that the opposing team has a minute amount of balls to use.

Re: Team 73 Defensive Bot (Almost There)
 

HEY THREAD, REMEMBER THAT THERE'S NO 'H' IN MECANUM!

Good enough?

Re: Team 73 Defensive Bot (Almost There)
 

That's a better solution than I was thinking of.

Re: Team 73 Defensive Bot (Almost There)
 

There are reasons to go mecanum for this strategy, but I don't think you will be more maneuverable with them than a traction drive. Mecanums give up both agility and pushing resistance over the standard rough top. But it's too late to change it anyway.

I like the concept a lot. I think it will need constant tweaking to keep up with the meta game. If your team is prepared to study offensive robots every week and ready to make on the fly changes to adapt and iterate, I'd go for it. Otherwise, it's too much of a gamble.

Re: Team 73 Defensive Bot (Almost There)
 

Okay, okay, okay. The only thing I have to add to this thread is that Mecanum wheels are not as underpowered as most people make them out to be. While our robot wasn't the best last year, we did make it to nationals with a broken robot playing defense with mecanums. Yes, the wheels have some give, but not if you're applying power to them. You obviously wouldn't beat a purpose-built high-traction bot, but you will be pretty close to evenly matched with everyone else (unless you did something... not right).

Given this, and all other things being equal, I would always choose mecanum wheels due to the maneuverability which is a plus while defending. The only problem this year is that our team is rather short on funding, and our design called for two of the CIMs to be shooting (I still think this is a bad idea).

Re: Team 73 Defensive Bot (Almost There)
 

I would make only one change. Tie a string across the front of the top frame, and hang a "deadening cloth" or something of that nature. That way you could "block" shooters that dont make it over 60" when it gets to your robot.

As it stands I don't really see you "blocking" anyone, as even the lowest of shooters need to get above 60" over a 30+" bot if the want a nice arc for shooting.

Nice bot however!

Re: Team 73 Defensive Bot (Almost There)
 

The orientation of the wheels seems to be incorrect, unless I'm missing something.

Re: Team 73 Defensive Bot (Almost There)
 

I was about to mention that. The wheels should form an X when viewed from the top and an "O" when viewed from the bottom.

Re: Team 73 Defensive Bot (Almost There)
 

Thanks for that catch. We will swap the wheels when the pits open at the finger lakes regional.