Team Eventorizon: Build Diary

[Mouldy]

Re: Team Eventorizon: Build Diary

Had nothing but trouble with dimention engineering products, try with a rx battery if it still doesnt work..

Also, i thought you were using tz85's? They have a bec built in...

[Eventorizon]

Re: Team Eventorizon: Build Diary

So, if I unplug the BEC then it should still work?
You guys have given me loads of things to try, so its just a matter of me working my way through them to see what works.

[grant_ploughbot]

Re: Team Eventorizon: Build Diary

If your running 2 ESC's with a BEC and a seperate BEC you could have damaged something. Your probably OK but your best to get rid of your external BEC and cut the red wire to one of your ESC rx cables.

[Eventorizon]

Re: Team Eventorizon: Build Diary

How do people slow there discs down. Binky's disc takes 2 minutes to stop from half speed cos of all the bearings. I don't want top remove the bearings as it will wear away at the supports. But I don't think driving into the wall is a legitimate breaking method?

[Merkabah_PT]

Re: Team Eventorizon: Build Diary

I think i read about something like an electric brake on the riobotz tutorial. You might want to check it.

[Max]

Re: Team Eventorizon: Build Diary

You could use a magnet to slow it down a bit- if you have a spinning piece of metal with a magnetic field going across it then it will slow down and be harder to spin. If you connect a magnet to a servo arm then you could engage this brake at the end of the fight.

[plargen]

Re: Team Eventorizon: Build Diary

you could use a bicycle brake pad on a solenoid or servo just to push against the side if its smooth to generate some friction to slow it faster

[daliad100]

Re: Team Eventorizon: Build Diary

Or turn off disc throttle and just short the motor out. Same principle, just simpler.
Might want some load though to reduce current at the expense of increased slow down time.

[Eventorizon]

Re: Team Eventorizon: Build Diary

The system is fitted with a one way clutch so that we can turn the motor off and the disc will still spin freely, but shorting the brushless sounds like a really bad idea.

It will probably boil down to a servo/solenoid and a brake pad as there is a nice flat ring running all the way round.

[Mouldy]

Re: Team Eventorizon: Build Diary

Kind of a pointless rule IMO, ring Grant / James and see what they think of the 60 second rule... i wouldnt fail a robot on tech check for it, and if there happy to run it at the event i dont see an issue.

[typhoon_driver]

Re: Team Eventorizon: Build Diary

If you rotate the bot quickly on the spot it will reduce the energy in it as well from gyro forces and I haven't ever seen anyone standing with a stop watch at the side of the arena

[grant_ploughbot]

Re: Team Eventorizon: Build Diary

We've had robot's with this in the past, particularly in featherweights a very free gearbox/bearings is essential so we won't be banning anything that can't spin down fast enough.

However, there are a few provision's that we take with robot's that do take longer to spin down and these will be discussed during tech check (Mouldy will be made aware of these, but it's nothing major).

[Eventorizon]

Re: Team Eventorizon: Build Diary

Two points/question today...

1:Can we know the provisions in advance for the spin down?

2: With Aluminium grading I know approximately the relative costs and better over all properties of each grade but when it comes down to it which would people choose?

1060 is far to weak to be used as armour in internal supports; it just bends.
I have heard of 2014 and 5052 being used in robots.
6061 and 6082 seem very similar but are both better than the first 3 as far as I know.
7075 is the 'best' as far as I know but is it worth cost increase from say 6082?

[grant_ploughbot]

Re: Team Eventorizon: Build Diary

For bulkheads and axe arms etc then 2014/7075 are about the best. For welding go with the 6082. 5000 series is abit soft and cheap.

With regards to the provision's, its nothing to do with how you build your robot, just a few pointer's for during the event.

[Liftoff]

Re: Team Eventorizon: Build Diary

Make sure you know what temper of aluminium you're purchasing as that largely effects the strength of the material.
If your're getting 2024 type, temper T0 its rated approx 200Mpa in tensile strength, while in T3 temper its rated approx 300Mpa. Same with 7075, T0 is 300Mpa while T6 is 600Mpa.

7075, and 2024 are aircraft grade aluminium so I think they might be slightly expensive or hard to find.
I've used 6082T6 which is half way between 2024T3 and 7075T6 and its widely available.

Something worth noting is that these alloys are not easy to bend and form and have a tendency to crack in tight angles.