Liftoff (FW) build diary

[Liftoff]

Alright, so back from the drawing board with another design, hopefully should be functional now! The basic shape is still there, but materials will change from HDPE to aluminium... just hope I'll still be able to keep within the weight limits!!

Tracks will be mounted onto an aluminium cased, bolt on module complete with drive motors. The baseplate I'll change from 5mm HDPE to 3mm aluminium, trying to source some strong alloy though, was thinking 6061 or 2024... anyone knows where I can get hold of a 500x500x3mm piece? Preferably from within the EU, all I found on ebay were from the states - shipping costs are astronomical !

A couple of pics of the new simpler system.

track drive1.jpg

Tensioner is not included in the pic, but I'll use a roller on the top side of the belt for tensioning.
Will be adjustable by an eccentric shaft.

track drive2.jpg

[Dan-27]

Might be worth sending this guy a message and see if he'll post out to you.

http://www.ebay.co.uk/itm/aluminium-...5f5031ccb#shId

Also I came across this article last year, it's not exactly what your doing but it might be some help. I was wondering if you could do something similar by running 2 bike gears on either end of the roller, 2 chains between the rollers and secure the belt onto the chains somehow. It would be loads heavier but wouldn't move sideways.

http://woodgears.ca/tracked_vehicle/

www.woodgears.ca is a great website to trawl through, his gear generator is particularly useful.

[Liftoff]

I'll check him out, don't know what type of alloy he has though, its listed as grade EN485, but that's not a grade I ever heard of...
Chains and sprocket is a good idea, as you mentioned weight will be an issue, but its an other option.

Bumped into this website by chance, dont know if anyone ever bought something from them, it looks interesting, they even have a complete track drive system, and its not expensive at all...my only concern is its plastic!
http://www.vexrobotics.com/vex/produ.../276-2168.html

[Liftoff]

Small update:
Got the armour cut and it's now back from the shop.
The large plate is the flipper arm, the other plates are the front and side armour. I opted for the front and side armour to be cut in small parts mainly for two reasons...
firstly, the material came for free but in the form of small pieces from which I could cut just one item....
second reason is that if a part is damaged I could easily replace it.

Also received some various thickness of hdpe to which the armour will be bolted.
I think 4mm titanium and 20mm hdpe should protect well against spinners...at least I hope so!

Have ordered some aluminium plate and box section for the chassis...still waiting for their delivery...and then back again to the waterjet shop to cut everything to size.

I've had to scrap the previous machine and build a completely new one from scratch as the old chassis was simply too flexible to work with. The shape will still remain the same though, only the name will change. Might start a new thread later on when I start to work on it...

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[Eventorizon]

Are you going to be bringing the weight down so that you can come and play with us at the Champs :-) That would be awesome!

The main thing that stands out for me is using lots of small pieces to construct your armour. There will be more things that could potentially break and if something does go mid fight then you are going to be very vulnerable as more can be ripped off from the resultant hole left in the armour. (This is assuming they are not welded into one single piece.)

Have you successfully resolved your track issues as well?

[Liftoff]

Sure, now that I'm starting afresh it should be easier...and yes I'm hoping I'll be able to enter it in next year's Champs. This November I'm coming over to the Gloucester event, that will get me a bit familiar and hopefully meet some of you as well.

Regarding the armour, I really had no option as the material I had was not a full sheet. Thought about geting it welded, and in fact I might as well go on with it, the thickness might be a problem though but I'll ask around... btw its being mounted on 20mm hdpe, so even if a piece had to come off, it'll still have some protection.

The tracks should not be an issue now, the system is a simplified version of the previous one, now it will be totally encased making it impossible for the track to come off. Have a look at 6th post from top.

My main problem now is the lathe, have lots of parts that have to be machined and not having acces to one I'm seriously considering buying one...but that might take some time to happen!

[Liftoff]

Update:

So I just found out the local robot wars event will be held on the 10th November...perfect timing, the same day I booked for the Gloucester event! Tough luck! Will have to give the local event a miss...

Still, I have a robot to build and that will have to be built almost from scratch in 3 weeks! Looks like a mission impossible to me, but worth a try. My brother will take it to the fight if we manage to finish on time.

The tracks issue will hopefully be resolved with the latest (and final!) redesign. Machined again a set of wheels and rollers, and this time every thing will run on ball-bearings at both ends for better rigidity.
Yesterday had a new set of tracks custom ordered, I picked them up this morning...so far all is looking promising. This weekend will fit all parts together in the track holder and...fingers crossed!

Will post some photos later

Edit: Photos added

Drive is through the red wheel, will have to grind the motor shaft to 1/4"square. The middle roller is an eccentric tensioner. The other roller is the fwd idler.

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[Liftoff]

Good progress over these couple of days, built the first track module (sorry no photos yet) and most of the previous problems look like they're solved. To test it I coupled it to an electric drill as I still need to modify and mount the Gimson motor. It turns ok with minimal friction and the track stays put, one less problem to worry about.
Now I have to copy and paste to build the other module, and then the rest of the build...

[Liftoff]

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The assembled module less the drive motor.

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A view of the internals and a short vid clip in action.

[SamO]

"This video is unavailable"

[Liftoff]

Should be ok, now...took some time to process the youtube upload! The video shows how the interals look like, but in reality the belt and rollers will be mounted internally as shown in the first two pics.

[Liftoff]

The build is going on overdrive at the moment! Only have till Tuesday to finish it off and I really doubt I'll make it

So I got most of the structure finished, drive as well (still untested), Hdpe under armour almost ready, now I'll trim the base plate to size and screw everthing together. Next will be securing the pneumatics and then installing tbe flipper arm....still a mountain of work to do!

Progress so far:

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[harry hills]

Looks pretty solid. Very nice work

[Liftoff]

Thanks Harry... it looks solid enough, but that will only be confirmed in combat!

More work in progress, today sorted out the pneumatics and their attachments. I'm happy by the result, everything fits in to the millimetre. Also continued the hdpe under armour, tough work with the plane to match and allign the pieces, but so far so good. Still doubting I manage to finish by Tuesday but I'll try!

Some pics of the progress so far and a comparison of the old vs new shell.

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[Liftoff]

Feeling exhausted after a whole day at the workshop working on the machine...tomorrow is the last day I can work on it as on Wednesday will be off to the UK. Then its up to my brother to finish it off and make it work for Sunday's event!

We're almost there, track drive installed, tested individually but not as a whole unit, so so far its untested!
Flipper hinge and allignment in progress, but there's still loads to do! Most probably it will have to do without the titanium armour for now.

Some photos of the robot so far.

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Playing with fire!!

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Overall view of the robot, its looking more complete by the day, hope it will function as it should in thd end!

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