Questions abt anti tips

Should the things at the end of the antitips be inwards our outwards (I have two antiptips, one on the left and right. Both are in the back)? Are anti tips locked in place or rotating? Pretty sure they are locked in place but I just wanted to verify before I screw something up.

What do you mean inwards vs outwards? Sliding/flipping in? Whatever works for your robot. Mostly they’re rotating out because of size limit, with a joint and a lock being released to flip them.

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@Doctortictac is correct when he says that you should use whatever works for your robot.

I think it would help us a lot if you clarified what you meant by ‘the things at the end of the antitips’, and if you specified the style of anti-tips that you were using. Pictures would definitely help us all.

With that in mind, there are a few generalizations that we can make regarding anti-tips. They need to be strong enough to support the weight of a robot leaning on them, and they need to be durable enough to remain functional throughout the duration of a match (that is - not be hit and fall off, get pushed back in, or rendered useless).

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image

@Doctortictac The red is the back of the chassis, should I have the antitips where the blue or green circles are? It’s not to scale, the anti tips will be farther away from the chassis. @ranOOm ATM the “things” are 60t gears covered in mesh, but that isn’t finalized and might change in the future

I would use omnis with green inserts instead of a gear.

You would want them at the green because that is easier to make and it supports it well if they’re out enough. 1961Z has greens and they work extremely well in matches, if you watch them.

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Ok - a few things.

Where you place your anti-tips, whether the green circle or the blue circle, is entirely up to you. To help you with your decision, farther apart anti-tips help with stability of your robot when you’re on the anti-tips (less chances of tipping side to side), but an anti-tip closer to the center of your robot will make your robot less wide at the back, and may make it easier to drive around (if your driver will notice the difference).

You should try to make your anti tips something that can slip sideways - omnis are going to be a better option, use a screw-joint on the wheels and you should be ok.

Another common end piece if you don’t have room for omni’s is a spool from the winch and pulley kit with surgical tubing stretching around the circumference, and spacers on the surgical tubing loop. Basically creating “custom” omnis that are much more space efficient

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I would not recommend this.

Try to use 2.75" or 3.25" omnis.

@ranOOm have you had bad experiences using this method? I’ve seen a lot of robots use them without issue.

I believe that if we outline the functionality that anti-tips should provide, their job is to prevent the robot from tipping, and to otherwise not hinder the movement of the robot. Their job is to do this, continually, throughout a match, without fail.

The more complicated something gets, the more parts there are that can fail. When you wrap surgical tubing around a pulley, and then put spacers on top of that; there’s two significant drawbacks.

  1. the ease at which these can be damaged. It’s easy for surgical tubing to wear out, for spacers to be pushed off under heavy defense, or for the pulleys to snap. ALL of these could compromise the use of your robot if you’re dependent on the anti-tips.
  2. The fact that these don’t roll sideways all that well. This means that there’s more friction when your robot is trying to turn on field than if you had omnis; which doesn’t seem significant, but in vex every little bit does matter.

That, and the fact that it’s not significantly harder to use omnis, I don’t see a good reason for using spacers pulled around a pulley.

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I have tried the custom omni wheels before, they don’t really work any better than using a gear or a plain pulley tbh. I’d recommend 2.75" omnis.

side flip out antitips aren’t your only option either. I’ve seen omni wheels on slides that linearly extend out of the rear of the bot work quite well. I’ve also seen antitips that flip out top down. imo the top down is the best because its a lot easier to make it rigid and strong. the difficult part about top down flipping antitips is locking them down once they deploy, but there are a few ways to do this.

I was planning on using wheels before but the problem is the their too wide and would be up against a motor powering my back wheels. I don’t have much room until I’m out of size constraints so I used a gear. I don’t have the equipment required to cut wheels in half nor any places nearby that can cut them for me. I can order pulleys and use those but from the looks of it pulleys aren’t a good idea

you don’t have access to a hacksaw? you can cut 2.75" omnis in half with a hacksaw pretty easily.

I did not know that. I’ll have to try that out and hope I don’t ruin my wheels XD

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don’t do in unless you have to. if you post a picture of the back of your bot we can help you come up with another option.

K I’ll be back home in 20-30 min so I’ll do it then

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ok so you have a lot of room back there. you could easily make top down folding antitips, or linear extending antitips. I wouldn’t cut omni wheels just to have flip out antitips tbh.