Bot Building Questions!

[bot_bandit]

So after reading about the difficulties had with Ti I went for 1mm aluminium which cut more easily than polycarbonate did! I just used a regular pair of scissors.

Anyway, I'm back with more questions! I'd like to build a vertical grabber robot next. I was wondering what servo is recommended here? As well as this, whether it is more effective to attach the claw directly to the servo arm or whether to use a four-bar method (like a reverse flipper)?

[Shakey]

Just be aware the easier it is for you to work the easier it is for a spinner to destroy!

A direct attachment is less robust but normally you lose some power in the 4 bar methods so it's really a trade off you have to decide between.

[bot_bandit]

I'd barely hit send and you've already replied Alex! Thanks again for the advice.
The thin armour shouldn't be too much of an issue as it's on top of 1.5mm polycarb giving 2.5mm armour total. It was more to add weight and to make the bot look cool than any serious protection (although it will help).
It's a hard choice to make between the two!
I was also thinking of covering the front wedge of the grabbing robot in some kind of rubber to make it grippy and help trap the other bot. Would this be against the rules in any way? I don't think I've seen it done before

[Occashokka]

I don't see why a grippy pad would be banned, in fact Pete put one on a flipper so I don't see why not, the only issue with a vertical grabber is that if you bring the top claw down they still have wheels on the ground and you need to be able to out push them and if you lift both or the bottom claw then you need to balance it so you don't fall forwards under the 150g temporarily at the very front. But that doesn't mean to say you can't build a good grabber and not many people have them do don't let me dissuade you

[AntRoboteer]

The only issue I foresee with a grippy pad is that the opposing robot would have to get dragged all the way up the pad in order to get stuck on it. If the grippy pad is grippy enough to hold the robot, the robot will probably not even make it's way up the pad at all or at least enough to be effective. That's the reason why I've always stayed away from this in my grabbers.

[bot_bandit]

The plan was to have a long and slightly angled wedge at the front.. just enough to get under the bot and get their wheels off the ground (hopefully), with the battery, wheels servo etc all being at the back. However this would involve some good driving to get them from either the side or the back. A lifter grabber could be quite effective, one won battlebots last year. However being just my second bot I don't know how confident I would be with tackling something like that. Wouldn't be sure how to wire extra servos/program them correctly. I'd probably need a more clever transmitter too an those are expensive :/

As for the pad being too grippy, could driving at the other bot fast enough or ramming them into a wall solve this issue? Perhaps just have the grippy pad a little further up? I do agree that this would be an issue

[Fenrir]

If the Titanium's still an option for you, Id recommend a pair of Stanley Fatmax aviation snips for just over £10 including delivery. They cut 1mm nicely, and in conjunction with a clamp or vice, work effectively as it tends to bend the titanium when cut so with a clamp you can bend it back afterwards. I've just cut out a second claw for Roc, my vertical grabber robot. It gets quite a nice grip with the claw it already has, although the servo tends to lift up the top panel when it grips things tightly, partly because the top panel is only screwed on in three corners; and it's attached directly to a servo horn in two places so it doesn't dislodge easily.

[Occashokka]

1. I refuse to admit bite force was a grabber and lifter lol more like 'scoop occasionally featuring prong things'

2. I would probably put the grip on the claw not the wedge as then you only have to release the grip with the servo to let them go

[bot_bandit]

Titanium is definitely still an option. I could do with some better scissors anyhow as I don't want to keep blunting all the ones in the kitchen.. I'll have to get myself a pair!
One concern I had was that when grabbing onto a robot the servo could try to tear itself out, which is which I was wondering which ones you guys went for?
Haha that is true about bite force!
Having grip on just the claw may be the way to go, I guess that avoids entanglement too. Thanks for the suggestions guys!

[Shakey]

Grip on the claw is a decent option, I had plans for a grabber where I could just put a tyre on the end of it as a slightly squishy grippy bit