Team Death - New Heavyweight

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For me, the most important thing in robotic combat is a trick I learnt in some games, especially EVE Online. Which is basically "Never carry or fly something more expensive than you can afford to replace". I personally would apply the same to this sport, and make sure we can always afford to replace whatever can die before going into a combat situation with the bot. You never know how many pieces it'll come out of the battle in, and how quickly you'll need to replace and repair before another battle, if despite the damage you still go through to the next rounds.

In more light news, I'd completely forgot we still had the trolley to do.

[team death]

Access All Areas and Practice What You Preach......
It's the weekend again and a double shift on the Robot done.
This Saturday morning was dedicated to fabrication once again
and my attention was drawn to the rear end of the Robot.
There was quite a large space to be filled and I had discussed
with Adam various options in the past but probably not the one
I chose in a surge of inspiration.
Practice What You Preach.....
Earlier in the year I had tried to sell a mains powered 9"" angle grinder
with a view to someone converting it into a dc powered weapon.
No takers so by means of demonstration and to fill a space on the Robot
I thought I would show how it can be done.
The Grinder which is faulty by the way was stripped to it's component
parts-armature/stator/geabox and casing and a suitable doner dc motor
was found in the workshop.
This was not a straight forward fit, the brass lugs that hold the brushes in
place had to be cut off and the stator had to be sliced in two just before
the gearbox and a universal joint was fitted between the dc motor and
what remained of the stator, the dc motor stuck out of the original grinder
casing too much so I found an old tyre off something I cant remember what
that was a snug fit and screwed it in place using the casing holes and screws.

Access all Areas......
Sunday -Adam and Niall were due a noon so I thought I would have a bit of a
tidy round, It's been a very cold day and I thought none of us will be wanting
to stand outside so I will make a little space in the anex next to the workshop
for Niall to do his soldering ect, I put in a little work bench and a lamp and made
it cosy.
Unfortunatley due to transport delays Adam and Niall couldn't make it today but
the new electrical prep area came in handy for me to test the grinder.
So the question was-will the grinder shake itself to bits due to badly aligned
motor/stator joint-no-it was perfect-no vibration, just a gentle grinding noise
from the grinder gearbox-probably needs some grease.
I turned my thinking to how to mount it on the Robot and once again the
advantages of keeping bits came up trumps.
Adam and myself had gone halves to a trolley jack early in the build but
had to discard the idea, now though the jacks body was perfect for brackets
to hold the grinder in place and by next Saturday I hope to weld it in place
and the fabrication will be 99% complete
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Ginder in bits/ motor to stator connection/ prep for cutting stator / new electrical prep area /grinder in bracket

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Yes, unfortunately myself and Niall got caught up waiting for buses that never turned up this morning. I don't mind too much, as unbeknownst to myself, York had arranged a large parade and events for Remembrance Sunday which is of course a very noble cause. So I'm not too irritated with the delays.
I'm glad to hear the building went on without us, and I don't think these weekends with myself & Niall not being around is causing any major delays to the construction of the robot quite yet, thankfully.
All been well, no expected hold ups for next sunday, and we'll be back at it with lots more progress and images for everyone.

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Another Sunday has passed, and more progress to report.
This weekend myself and Colin got together and worked on the bot.
We started out trying to get some life out of the ESC, which according to a friend of Colins was in functioning order. However we failed to get that going once again, and this time around didn't make the mistake of spending a lot of time on it as last time we wasted around 1hr15 on it.
So we moved on to the bot, and some more fabrication. The bot now has a polycarb base to it. The PC was cut in half, and double layered. Offering around 11-13mm minimum of protection, held together by some bolts. Colin got the big tools out after a while of me manually sawing through it, and we ended up breezing through the cut with a circular saw, and then giving it a go over with the buffer to get rid of the crusty edges and remove and defects that might cause it to weaken where it was cut.
The original plan was to use some half cylinders (think small fire extinguishers) to cover it up, but after doing the cutting, we thought it didn't look as good as it could be, when we remembered we still had the polycarb left from the bus graveyard several month ago that is yet to be used.
There is also the rear extra weapon Colin added last week, we'll probably turn this into a small flail to discourage people trying to sneak up behind the potential weakspot that is the rear. Also added by Colin since the last visit, is the back plate at the end of the tail. It'll hopefully help us be a little harder to flip, and right things quickly after they happen.
There has also been some minor additions to the side of the front neck, adding extra protection from side swipes and buckling to those regions.

The bot has also been weighed again, and we're up to the 100kg mark now, so not too much left to go.


Images!
1) No smoking in the Arena, even those e-cigarettes!
2) The new home for the polycarb, on the base of the bot.
3) The original plan for the base was to cut this roll up and use it, however we were unhappy with the untidy look it gave it.
4) The overhead view of it all, note the circular part on the back, this is where a flail will likely go on the end product
5) Current weight



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[team death]

Another cold Sunday but Robots don't build themselves although when
it's this cold I wish they would.
Adam was visiting Sheffield this week so I set too on my own
where we had left off last week.
First job was to fabricate a pillar to support the polycarbonate sheet
we cut to size last week-I found a suitable square box section with a
handy T section on top and welded it in place, a small piece of angle iron was
also welded to the snakemaster bar and the polycarbonate was bolted on top.
A while back I had cut a hole either side of the wheel covers to give better
access to the wheel bearing bolts so I added some hinges to the cut away piece
and revited them into position-secured by a bolt.
I had come aware of how close we were to the weight limit for heavyweights
-last week we weighed the Robot and I thought there is between 5 or 8 kg to play
with.
I worked on the front section with this in mind, drilling large holes in the fabrication
metal to keep the weight down-this has advantages for inserting a captive bolt or
nut if needed.
I welded on these box sections with thier captive bolts as added battery protection,
there was some polycarbonate left over and this was just enough to cover either
side at the front of the Bot like cladding and this was also bolted in place.
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[Samy]

Very nice Build Thread and cool Project!

[team death]

Christmas- its time to hang up your stocking and disharge your Lipo's.
It's advised that Lipo and some other batteries are discharged if not in
use for a while. so with the winter holiday period approaching I chatted
to Adam about doing this.
I suggested we could run our batteries flat on one of our motors so we
tried this method-the battery easily run the unloaded motor for 8 minutes
and there was only a 0.3 drop in voltage after this so we connected the
turnigy charger and set it to discharge-this method was very slow but it
let us free to do other tasks.
We worked on the castor suspension first by cutting two angle brackets
to support the castor hinge at a higher level, I estimate 70% of the weight
of our Robot is at the front and the castors should make the front more
balanced and responsive to steering.
After welding the castors to thier base plates we looked to the scoop.
Originaly the return springs were set inside the scoop jaws but proved
unreliable and kept breaking so now the springs will be external and run along
the back -this will make them more vunerable to axes but it will be real bad luck
if we manged to lose all return capability.
Each modification comes with a consequence it seems, so the external springs
will lift the jaws off the Arena floor so we have made a beefy spike at the front
of the jaws as first inpact zone-to lift the enemy bot into the scoop-In Theory.
We are hoping to sand down the bodywork in our next session and give it
a lovely two tone paint job.
Here's some pitures
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[cosmin]

Careful there, for storage you're supposed to discharge LiPos down to around 40% capacity, not fully. Most chargers have a storage mode which gets the batteries to around 3.8V per cell for that.

[team death]

Thank's for the heads up Cosmin-our intention was not to fully discharge the
batteries and Adam mentioned a similar % rate as yourself but for Lipo battery
novices like myself that storage mode is usefull info-I have only ever used gell
type batteries in the past which were heavy and quite short lived in a battle,
while comparing the two I was Amazed at the power of Lipos compared to Gells.

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I was always taught to bring them down to around 25%, and definitely not over 60% when expected to be unused for more than 1-3 weeks.
I've never experienced LiPos degrading (capacity/ max voltage wise) when brought down to 25% for storage, but perhaps 40% also offers the same sort of protection, and a little quicker to bring them back to life too if they don't need to charge so much when brought back into use.

When I joined to help, I was quite eager to introduce Colin to the LiPos, as he has been out of the robot combat scene for most of the LiPo introduction and rise phase, I managed to impress even myself with the weight difference, as i'd never really used or even held the old style batteries before, so didn't realise how large and heavy they were in person.

[team death]

Last update before Christmas and the new year...........
This week was designated as a painting weekend but I got slightly side
tracked and Adam was attending a Christmas do so I thought I would
tweak the mechanics of the jaws instead.
It had been bothering me that the winch jaw puller did not have a
clear path to the chains it pulled upon-namely its own drive motor
got in the way so despite it being a working system there's allways
room for improvement.
The original system was driven via a two sprocket chain to cut down
on the length of the single chain as detailed previousley and the winch
was set well back in the robot to pull the full length of chain.
I decided that if the winch was placed where the two sprocket roller
was I could negate the need for that roller sprocket and keep the chain
nice and short.
The covering polycarbonate lid didnt fit so I had to modify it and added
a curved plate to the front as a finishing touch.
Although the springs pull back the jaws after each bite, there is need of
a physical stop on the winch to stop it unwinding itself because it is also
powered return via the motor and has been troublesome.
At the moment I have put two short springs on top of the jaws-these need
rather too much energy to close the jaws so I think one much longer chest
expander spring at the side will work much better as in the previous jaws video
but not accross the front of the jaws.
I have added a long tooth to the middle of the jaws-made from 10mm steel
which sits on top of the spike and should help the enemy into the jaws.
Heres some pictures
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Merry Christmas

[team death]

Holiday break over and we returned this Sunday to progress
with our heavyweight Robot-which Adam will detail shortly.

Over the Christmas break I was tempted to tweak a few outstanding
bits on the Robot and I had previousley described moving the winch
around for optimum operation.
My attempt at modifiying the position turned out to be a failure,-the
torque was much less and it still interfered with the drive motor, so it
was returned to the original position and a longer pull chain was fitted
which goes right round the drive motor and the end result is near perfect.

This Sunday was set aside for painting and electrical work so in preperation
I sanded down the Robot a little and used primer on any bare metal areas

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and now for my input on the day!
As noted above, the majority of the day was spent purchasing and applying the first layer of paint, with some electrical work later on.
We started off by buying the paint, whilst possibly not the cheapest option, we decided to go to B&Q as they have a wide range of colours, and an on-site mixing suite for anything not in a tin already. We decided on a color, waited on it mixing, then set off back. As soon as we got back, we wasted no time and started applying the first coat. It's now pretty much a solid red everywhere, an image of which is below, later on we'll get some black for the chassis pieces, to add some contrast. It didn't take us very long to get a coat on the bot, although we expect we'll need to go over it again and touch up areas covering up brighter colors, or just missed spots. We also may need to do some extra work to cover up a few logos and text on the components we used, as certain hosts may not approve of a 'Calor Gas' logo visible behind the paint, so that might need grinding off or more layers coating over.

Afterwards, we got on with the electric work. We're still having very little luck with the speed controller, so as a work around, we've put together a simple relay system that'll allow us to get the bot moving, and test what we need to with it. It isn't the ideal solution, but it gets us to where we want to be with the progress of the bot, and will get the bot as a whole into a working order, and certainly allow us to do some needed human related tests to figure out who is going to be the driver of the bot, and may also be fine for competitive use should we not resolve aforementioned issues with the speed controller.

Colin & I would much appreciate any input on getting a speed controller working, or repaired, or even anyone local to pop by one day and offer advice or even repair in person.


Some images for today,
1) Some colour comparing at the local B&Q
2) The first layer of paint is on!

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[team death]

Sunday update-After last weeks painting session I thought I would
take a few pictures while the Robot was on it's wheels and I'm very pleased
with the look considering it's very much an undercoat and the final coat will
be applied a week before our first event to allow time to dry.
Adam was unavailable this week so I set to on my own.
I picked up a seedling planter from a rubbish pile and thought it may be quite
effective set into the air intake vents/wheel gaurds on either side of the Robot-
so I cut it to shape with the grinder and inserted a piece at one side, I may
run with the idea, but the other side would have to be a half section due to
removable link being located at that side.
I told Adam I would check out the temporary relay system to see how it coped
with with driving the motors at 24 volts via 2 gell batteries (static test).
This worked really well and even when the wheel was suddenly reversed there
was no arc on the relay and the chain did not break-so we may be able to have a
run around with this set up if we conciousley be kind to the circuit and don't suddenly
reverse the Robot like in the static test.
We are still unsure what to do about a permament speed controller after getting
our fingers burnt with the last one and it may be the batteries we have may not
suit all speed controller types-it would be a shame to spoil all the good work by
not having a control system as least as good as the competition has.
After testing the relay I worked on the external return spring for the jaws
and although this meant grinding off a little paint to weld, it was interesting to
see how well it scrubbed back and I was pleased that it was almost like grinding
on old bodywork.
Lastly I painted over any bare metal with a primer.
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We have stuck with the agricultural/industrial paint scheme and overhall look and
I think the Robot woulden't look out of place in a country agriculture showroom
even if it leaves you perplexed about it's application

[team death]

Wintery weather Today but the build must go on- unfortunatley due
to the bad weather Adam was unavailable this week.
I had planned to use most of today on the electrical side of things
but due to me working on my own I thought I would do outstanding
fabrication first.
Early last week I ordered a couple of things of e bay and they arrived
in time for this weekends build.
I bought 2 cheap speed controllers at £8 each -they are rated at 7-16 volts
and 300 amps and I bought 2 weightlifting bars to complete the fabrication
of the jaws.
Fitting of the weights bar to the front of the jaws was quite straight
forward, it just needed slight shaping and welding in place.
I then needed to cut a false tooth out of a car disc brake which I had used
on previous occassions for various things and I welded that to the bar.
Now I turned my attention to the never ending saga of the electrics
and namely the speed controller-I could be green with envy at other roboteers
who say " controller arrived and five minutes later it was running around "-
this hasn't been my experience-the Ragebridge blew with a massive spark
as soon as it was plugged in, so before we commit to another I'm doing some
experiments.
So my thoughts were-how would a £8 speed controller designed for small RC
cope with driving a heavyweight ?.
Bearing in mind my motors are 24 volt and the max current of the speed controller
is 16 volt I wasn't expecting great performance.
I tried running it at 12 volts on a gell battery to begin with and it worked well
(wheels off ground ) and then I tried our 14.5 volt lipo battery and it was slightly
better going forward and backwards no problem.
Whether or not the ESC will blow when the Robot is on the ground remains
to be seen-I have heard that the ampage rating is not the true rating ?-
What I do know is that I can wire them up and why the Ragebridge blew
is still a mystery (possible overvolts) but Adam thinks not.
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