New Off-season Defenses

[Karibou]

Originally Posted by DareDad

In exactly the same way. A 12 foot loop of chain can be raised well above 4' 6", it isn't as simple, but should still be quite possible.

Many tall (and short) robots relied on the motion of the portcullis to get through it. One push (or ramming into it a few times, in some cases) would send it flying high, and they could quickly get through it before it came crashing down.

[Doug Frisk]

Originally Posted by Karibou

Many tall (and short) robots relied on the motion of the portcullis to get through it. One push (or ramming into it a few times, in some cases) would send it flying high, and they could quickly get through it before it came crashing down.

The Portcullis is gone. I offered up a manipulation defense that it functionally similar to the portcullis. What do you suggest? What are you willing to build in your garage to bring to off season events?

[CalTran]

Originally Posted by DareDad

The Portcullis is gone. I offered up a manipulation defense that it functionally similar to the portcullis. What do you suggest? What are you willing to build in your garage to bring to off season events?

Let's tone it back a little.

While I do like your chain idea and think it would have made an interesting defense, the reason people are a little skeptical is because while similar, the chain would act vstly different than the Port. Most Port manipulators were also built with the bottom of the "door" being a solid bar. Ideally, any replacement defenses are actuated similarly to existing defenses so as to not require a completely new mechanism be built in the off season.

[carpedav000]

4-bar linkage portcullis? Seems like you could counterbalance it to where it spring assists up and then gently glides back down

[Karibou]

Originally Posted by DareDad

The Portcullis is gone. I offered up a manipulation defense that it functionally similar to the portcullis.

I would argue that your suggested defense is not functionally the same as the portcullis, because of the reason I stated in my post. Some robots might be able to use the exact same mechanism on your defense, or a very similar one, but not all of them.

I'm not saying the chain is a bad idea. I actually think that, if we are considering all ideas for portcullis replacements (similar or not), it would be a good challenge. I'm just saying that it is not functionally the exact same, and if we are looking for an exact (but safer) replacement that would not require any existing portcullis-capable robots to change their design, that's not it.

Originally Posted by DareDad

What do you suggest? What are you willing to build in your garage to bring to off season events?

Honestly, I don't have a suggestion right now. I'm glad that nobody else will end up being hurt by a portcullis, and for that reason I will be accepting of whatever replaces it.

I think that some of the ideas presented in this thread are good (I particularly like the "rolling log" ones). If I had a garage and the equipment to do so, I would very gladly take the time to build any one of these ideas.

[ctt956]

Originally Posted by DareDad

I emailed Mark Lawrence yesterday a suggestion that the new defense be a 12 foot length of heavy chain encased in a vinyl tube suspended across the platform with the center of the loop 5 inches above the bottom platform.

It provides a challenge that is similar to the portcullis in that you have to lift the chain up and over the robot, but is easier in that it swings out of the way and harder in that the chain can catch on the robot as it passes under.

The vinyl/plastic cover is of course to prevent the chain from completing a circuit as it drags over your robot.

To me, this sounds like the original low bar, just...higher. If so, it could be functionally similar to both the low bar and the portcullis, allowing robots to pass through just by pushing the tube, like the tubes on the old low bar. Maybe then even bots too tall for the low bar could get through this.

[wlaroche]

What about putting the flat base for the portcullis in the slot and allow teams to cross whenever they like. The difference being that the crossings will not count till the last 20 seconds. So you can make the deicsision on doing crossings or climbing.

[adciv]

Originally Posted by Alan Anderson

Many drivers would like to see the Drawbridge and Sally Port gone (or changed) because they are large and impossible to see through.

Is it bad I see the visibility issue as a feature?

I like a number of items which have been brought up, let me through in a wild card.

Allow teams to bring in their own defenses of whatever design they choose (within a few rules)
1) Can't fod the field
2) Must be possible to cross
3) If their robot cannot cross, the other alliance has higher priority for choosing to use it against them.

[dirtbikerxz]

Originally Posted by Alan Anderson

Many drivers would like to see the Drawbridge and Sally Port gone (or changed) because they are large and impossible to see through.

I personally hated the visibility issues (im the driver) since we have a low bot. But then again, I would not want them gone, because it was just another challenge of the game. It's like tall bots saying they don't like the low bar, so it should be gone.

Plus I also like the visibility constrains, because it separates the good drivers from the not so good. For example (not bragging here), after the first few matches at our first regional, i was getting used to the field and our bot. So even when I didn't have direct line of sight, our performance wouldn't degrade (unless there was defense being played), because I could still estimate exactly where the bot was based off of instinct, even making knocking out the sally port easy.

[EricH]

How about using a Portcullis-like setup...

But instead of springs, use a counterweight system, to keep the door at roughly 5 lbf up-force? (Maybe use a return spring to start it on the downward motion, though.)

[dirtbikerxz]

I personally am a fan of the following ideas:

1. Cheval De Frise stuck in the down position, it provides the challenge of not going so fast or slow that might cause your bot to tip over, (plus the airtime photos are going to be great )

2. Or a custom made variant of the cheval de frise ramp idea, so that teams can go over it from both sides, and not just one.

3. Somehow stick boulders in the defense base/holder, so a bot would have to drive over the boulders. Challenge is to not get stuck.

I really don't like the idea of having an empty defense with no points. Because once the other 4 defenses are knocked out, than shooter bots will just traverse the outer works using the empty defense, making it way too easy.... plus 3 ball auto anyone?. And also, that completely negates the effect of the secret passage.. (okay not completely, but still).

[Cothron Theiss]

I really like the idea of having a rolling log or logs as a defense, but I feel like it might be very hard to build consistently or reliably. Another idea would be to take the frame of the Portcullis we already have and mount double doors that open in the middle to the sides of the Portcullis that are already there. However, the difficulty of this defense is that one of the doors, say the left door, will only open towards the Courtyard and the right door will only open towards the Neutral Zone. I think this could be moderately easy to build, and a fun defense for teams to tackle.

[Jonny_Jee]

the bumps from breakaway would make for a neat obstacle.

[maxnz]

Let me ask this: Where exactly was the problem on the portcullis? I know what the problem is but I just want to know what part of the portcullis caused the problem. Then we could try to think of a new portcullis that removes this problem.

[Doug Frisk]

Originally Posted by maxnz

Let me ask this: Where exactly was the problem on the portcullis? I know what the problem is but I just want to know what part of the portcullis caused the problem. Then we could try to think of a new portcullis that removes this problem.

The problem is, the springs on each side are 40 pound constant tension springs which means the actual door within the portcullis is 85 pounds total. With the springs attached, the door can be easily raised to about 10 feet at which point the assembly becomes very top heavy and tippy. Without the springs attached, the door can be lifted even higher and I understand that may have caused an incident or two. The springs themselves are metal ribbons with, while not a sharp edge, and edge that can cut ungloved fingers as the door moves up and down. Think of someone running 4 feet of the edge of a tape measure across your fingers. The wheels at the bottom of the door present a crush hazard as they roll up and down as well.

The assembly when finished is very easy to tip and has no hand holds or way to lock the door in place.

So, an improved portcullis is:

• lighter.
• has no exposed counterweight components.
• has fewer sharp edges.
• has a door that can be locked in place during transport.
• has handholds for the field reset folks.

I'm sure there's more.