RogueTwo Robots

[PJ-27]

Re: RogueTwo Robots

Out of interest, what would you use on the shaft if you didn't have the collets?

I need something similar, that'll stop something moving along a shaft that also doesn't inhibit it spinning too much.

[RogueTwoRobots]

Re: RogueTwo Robots

Umm, probably just bearings. I would have used bearings for the back end of the motor shaft but I wanted to weld it on and I didn't know how well bearings would hold their integrity when subjected to extreme heat.

The collets don't really inhibit spinning much. There's marginally more friction because the shaft is spinning in something that's not moving or has rollers or ball bearings, but it's not particularly noticeable and I'd be surprised if you saw a significant reduction in rpm as a result of using a collet. I was planning on using these 8mm collets as a form of bearing for Paws' spinning disc (although I'll have to buy some more now!)

The only issue I can think of is that to limit movement along the shaft, these collets need to be fixed in place with the supplied grub screw, which then obviously prevents the shaft from rotating in the collet. This can be avoided depending on the application though, so it would depend on how you plan on using them (or mounting them) really.

[PJ-27]

Re: RogueTwo Robots

Hhmm something to think about. Way I see it your trying to reduce friction between the motor and the back mount, while staying fixed to the shaft to act as a spacer.
You need a bearing that has two independently moving faces while being able to spin freely on the shaft, but fixed in place also. :shock:

There must be such a thing. I'm thinking about my own robot design and just noticed your situation was similar.

[RogueTwoRobots]

Re: RogueTwo Robots

The back mount of my motor doesn't actually need the additional collet fixed to the shaft to act as a spacer. The shaft is fixed to the can and a combination of the magnetic attraction and a circlip at the front holds the motor together. I could run the motor with just the front mounting plate holding it on; the back mount is just to add support to try and reduce motor movement during impacts. So there's no lateral movement that needs to be restricted. I just added the second collet to the shaft because there was space for it, and to make it look better :P

[typhoon_driver]

Re: RogueTwo Robots

up at the higher end of the rpm range it could cause enough friction to cause damage to the motor. I'd coat the whole thing in grease to reduce this

[RogueTwoRobots]

Re: RogueTwo Robots

Update

Ditched the rear brushless support for now. Something wasn't lined up/welded properly and it was hindering the motor rotation slightly as a result; could probably bore out the collet hole a little more but will just stick with the front plate for now and see what happens.

Done a few wee bits and pieces on Drumroll over the weekend and tonight, but not a lot has changed visually so not much in the way of pictures. I've re-jigged the internals a little; the lipo has been moved from underneath the Scorpion XL at the back to the front next to the brushless motor:



Wasn't 100% happy with its original placement, plus the brushless ESC fits in better at the back than it does at the front. I've also fitted a foam-lined 3mm aluminium plate on top of it to hold it down, as opposed to the 1mm plastic piece I used previously. A decision somewhat triggered by the current discussions in the Lipo thread.

I can now also remove the lipo more easily by undoing the two socket screws that hold the ali plate down, whereas before I needed to faff about with wing nuts and four smaller socket screws to be able to take it out of the robot.
I've also got one of these:
http://www.giantcod.co.uk/power-battery ... 06643.html

that I'm planning on mounting in the robot so I can keep an eye on the total voltage and individual cell values. It's got a low-voltage alarm so should help with monitoring the state of the battery.

And finally, I've got the brushless ESC set up so the robot's now driving and spinning (just the motor). Still need to get a suitable belt to connect the drum as well as an inline fuse, but once I've got them then Drumroll will be ready to test. Then I can concentrate on re-fabricating the side armour and rear wedge (weight permitting) and paint it. Shouldn't be long now before it's finally finished again

[Anttazz]

Re: RogueTwo Robots

Amazing you manage to fit it all in that kind of 3-storey-towerblock-of-parts assembly you've got going there. Keeps it all compact I suppose.

Next job is to get Carcinus and your flipper going then go to Barnsley with us

[PJ-27]

Re: RogueTwo Robots

How do you still have spare space in there!

I've thought about getting a Li-Po alarm for Bitza, since we're using Electronize ESC's we don't have any of the built in Li-Po features of Sabertooth or Scorpion. Just don't know if I'll hear the alarm during a fight should our voltage drop that low.

[typhoon_driver]

Re: RogueTwo Robots

You won't hear a thing in the arena. The best way to get around the issue is to oversize the lipo. I ran boner for three fights last comp before recharging because of a lack of time to get parts repaired between fights. This was possible because my lipo pack was oversized for safety sake. I do not recommend running a robot for several fights without charging though!!!!

[RogueTwoRobots]

Re: RogueTwo Robots

The alarm on my monitor is pretty loud but, as Gary says, it won't be particularly audible in the arena. It'll be handy more when you've just come out of a battle to see what voltage you're sitting at.

I still have reservations about how long my battery pack will last. I'm limited by dimensions so will be hitting up teh intarwebz tonight to see if an increase in battery capacity greatly increases the physical pack size. If I can find something similar to what I've currently got, I'll probably upgrade before the champs just to make sure I won't be running low or cutting out in the middle of a battle. Hopefully testing will give me a better idea of how long the battery will last too.

No flipper chassis yet Tony, so little chance of getting it running before Barnsley. Not that I was planning on going anyway :P
Got those tank connectors unscrewed yet?

[Max]

Re: RogueTwo Robots

I bought that lipo alarm thing mainly for testing- I know the battery pack won't run out in a 3 minute battle but I would rather be ableto have as longer testing time as possible rather than having to stop and recharge the battery every 3 minutes.

[typhoon_driver]

Re: RogueTwo Robots

What is the capacity?

[RogueTwoRobots]

Re: RogueTwo Robots

2200mAh. Never used to pay attention to how much I used with the old setup in a fight, mainly because I didn't have a charger that told me how much had been put back in, plus the old batts were 3700mAh and the setup was less current-hungry, so a little top-up between battles was all that was needed. Will wait until testing to see what's what.

[Anttazz]

Re: RogueTwo Robots

Tank connectors are still standing their ground, I have been trying too, strained a muscle in my hip the other day there trying to get them off and i'm still feeling it Now my workshop has been temporarily dismantled and a car has taken its place so can't really do anything for a few weeks.

Thats a shame, if you wanted a ride with us I would try to convince my old man to give me a loan of his car, just got insured on it today, so you wouldn't be subjected to the Chevy again

With Carcinus and Eric Jr we can send um hameward tay think again an aww that

[typhoon_driver]

Re: RogueTwo Robots

You should be fine. Remember we used to run feathers on 1.2Ah SLAs

The brushless whilst being more powerful draws nothing (a couple amps) when it's up to speed. So you get a huge current draw at the start which quickly tails off. Make sure that the drum spins as freely as possible. Make sure you put some 3 in 1 or WD40 in the bearings.