Electric Axe featherweight - first build of FW

[Roboteernat]

Wow it's been a month since my last update.
What's happened? Well quite a bit.

Sourcing some hardox 3.2 mm is difficult, and my supplier can only get 6mm so that's out of e question.
Found some nice plate that will do for now tho, so just need to add braces to mount these on.
The chassis is now bolted together using some wood screw inserts.
New motor mounts made for the drive motors.
Wiring has been 50% completed and still not made the ax or motor mount for he axe.
What I did do tho is find my linear actuator which just so happens fits in the slot for the axe mech, so I could in theory have a lifter...

Pics to come

[maddox10]

Sourcing 3.2mm Hardox ain't difficult. Any commercial end user of SSAB steel can order a sheet.
Problem, a sheet is 6x2.5m

[Roboteernat]

Thats the reason why i have to stick with this stuff i found and not Hardox at this stage, 6x2.5 is alot for me, and the cost of getting it lasercut by Kcut was too much just for what it was.

Once i have had my first proper FW battle, then i can invest in more materials,

Attached is my pneumatic rams i have for reference to a sale.

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[Roboteernat]

Some updates
With great big thanks to Katch and his old Hard-Ox bodies, i now have some Hardox which i will cut and shape to suit the armour for the feather. This was the only thing stopping me from progressing with the build, oh and the base plate!
I intend to use some of the metal to shape some side panels so that there is armour on the side and not just relying on the 12mm HDPE.

I have reworked my motor mounts as the same as i suplied to a roboteer from 15mm HDPE, however this does mean my 4 mounting holes on the back panel are now over too much by 2 mm, so may have to modify something for this, perhaps a plate to support it and enlarge the holes sideways. Too much and the motors will not fit nicely and could bind on the side wall if there is too much of a bend made from impact. Hopefully the Hardox side panels will stop this.

I may also use the hardox to reinforce the base as i could end p using Polycarbonate 6mm as my material for the base plate, i dont want it to flex too much, so the supports will be made to reach across the whole width of the bot.

My axe motor mount needs to be machined but i have the 15mm HDPE for this and will make a mounting plate from 3mm aluminium.

The hardox is a godsend and will get things back on track. Am wanting to compete in Portsmouth (home town) and perhaps meet with the Chris in Southampton

Progress shots to come!

[Roboteernat]

So i borrowed my uncles angle grinder (Alan Grinder) and bought some new disks for it and cut up some panels from one of the Hard-Ox shells. From this panel I have cut out the 2 parts that form the sides of the bot, 4 pieces in total. Unfortunately the edge strips were curved and have somehow remained curved, probably due to the heat applied when they were welded together to make the shell of Hard-ox.
This means i have mirrored the pattern and cut out the reverse side to allow the curve to shape the other side. this doesnt read well. bit of an annoying day at work today.

Anyways, i nopw have 4 roughly cut out side panels to weld together.

[Roboteernat]

i really cannot leave it a month without updating this build however the lack of funds has caused no progress, except for this week, well today...

Last week my collegue gave me an arc welder, one of 3 he had lying about, so that was greatfully received, and after some needed TLC, the welder is a wonderful machine.
I was also able to borrow an angle grinder from my Uncle, and after purchasing some disks from ScrewFix i was on my way to rescuing some panels of Hardox from the donor chasis of Hard-Ox.
Today, i was able to shape some of the side pieces, and giving them a facceted look to the curves by cutting almost all the way through and folding along these lines.

Sadly however, my auto darkening welding mask that i already had for some years ran out of battery power so i couldnt actually weld anything.

Tomorrow i will grab some batteries and will commence.

[Roboteernat]

So now i have signed up for Portsmouth and Cheltenham, i need to make some progress. - Brief update as i cant really type for a long time!

I have been grinding the Hardox and welding, machining the brackets to hold on the plates.
Wiring has started, but im after 2 more TZ85A looking at alternative hobbyking turnigy ESC, otherwise its the Feather 2 from Alex.

I have aquired an electric actuator from a mobility scooter that just tilted the seat, it fits inbetween the gap where the Axe mech sits, and im thinking i could use it for a small lifter if the axe doesn t pan out. Testing on a 4S battery is good speed so with some level advantages i should be able to lift something before it drives away from me!

The one question i do have is the base...

Im thinkinng i may go for 6mm Polycarbonate as i have a large sheet available for me, but maybe HDPE? aluminium?
What do you guys use?

[Roboteernat]

I have gone off the idea of a base made from 6mm Polycarbonate, although i have a huge sheet from the tip - someone threw it away, was a shower screen! i feel like i need the strength, and should i be upside down on the receiving end of an axe, it can shatter.
So perhaps i need a trip to my local-to-work scrap yard and see if they have sheet titanium going. i have managed to get some bits from them before, so why not!
Anyway, this weekend being a snow day weekend, i thought i would get on with some robots stuff. Sadly today was a plan to grind the panels for the front out of the Hardox sheet but alas, it rained! So no outdoor stuff to be done.
i did make a start on my cabling and soldered on some motor connectors and plugged it in to my Electronise esc, although im really wanting to get the TZ85A. Sadly the stocks accross the country are none.
Luckily, i headed to my local fav auction website and randomly checked for TZ 85A esc, and wow, one appeared. So i grabbed it!
Now i have 2 TZ85A esc for my drive controllers instead of the electronize ones (i have 4 of them now)

The axe mech, im starting to think about using chain drive instead of single pulley as this is the way most rooters go. plus simply bearings, or bearing boys have an offer on.

I also wanted to print out some sample motor mounts for use on my bot - i sold 4 sets of them to someone after them for an R2D2, i wonder how he got on with them? Sadly i needed solid works to work on my laptop, but i couldn't access the activation portal so couldn't transfer my license from my work machine to my work-at-home machine. Therefore, i never did make these. Will just have to make them Monday at work on my CNC Mill.

Oh well.

So the next plan is to at work, use solidworks to correctly check what model of motor mount im using.
2. modify the motor mount to fit the new rear chasis shape and mounting options.
3. check that 18mm HDPE is good enough on the motor mounts.
4. machine up brackets to hold on the rear
5. go to scrap yard and find a suitable material for the base. Design has limited it to 6mm max.
6. grind out the front panels.
7 re-weld the other side panel that i did badly.
8. program and test the ESC tz85a
9. rewire everything including the lights.
10. oh yeah... the axe mechanism

the list can continue...

[Roboteernat]

Well, i deceided to take apart the linear actuator gearbox, as it was a solid lump of aluminium, with the aim of machining the block for less weight. Sadly in the process i knackerd my motor - the magnets snapped and i cannot remove the motor to reinsert the brushes, so i think it was a gon excercise in not doing that again!

So onto the next bits. My motor mounts for the drive are being machined as we speak.

As i continue to develop the chasis, im thinking now the base will be 10mm HDPE, i need to strengthern the backbone through it, so this is being upgraded to 20mm HDPE instead of 12mm.

I have therefore ordered more materials, including sheet of 10, 12, 15 and 20mm HDPE in black.

The axe mech has been continued, and have sourced appropriate metals for the spindle and motor mount. I have glued the magnets in the motor for the axe, but feel i should also continue to develop the lifter should the motor die.

Anyways, pics to come.

Thanks

My material stock has lessense

[Shooty]

This reads like an exciting build diary, though I have to ask. Are there any pictures?

[Roboteernat]

Ahhhh pictyres that would show off the weaknesses! Hehe no seriously, most of the updates are written during my tea break when I don't actually have it to hand to take the pics, will do however, as pictures are good.
Will add pics in he next post to follow all the work done before

[Maxamuslead]

look forward to the photos,


Side question have you looked at Team Run Amock hammer calc ? http://runamok.tech/AskAaron/tools.html

not sure how accurate it is as a brushless set i punched into it (practicing my CAD fu) and got a energy out of over 400 joules, where my current on is only 15 ish.

[Roboteernat]

So some developments.
As its been the Easter break i thought i would do a bit of construction to the robot. noting time is getting on, and im hoping to compete at Portsmouth.
Firstly, i had a rethink on the chassis, and although im happy with the majority of it, im thinking the main rib which stretches along the back, effectively strengthening the 2 halves together, is currently 12mm HDPE. i have decided to make this 20mm which will give a great big lump of support. The rest of the chassis im happy with as it wil be clad in 3mm Hardox, so i think this is ok.
This means i had to set up my other larger bed mill to machine the new plate. 1 more ebay shed in the garden later, and i now have it set up. sadly as the night was drawing in, i couldnt really start buzzing up and making it. so it was on with the electronics.

Great, i thought, now i can program both my ESC. Plug in my USBasp or my USBTiny into the PC and AVRDUDE, well well well, something is not going well... turns out i cannot get the devices to configure with this software properly.
Having said that, i do feel that i did actually get it to work, but by using the software from the brushed launchpad site, it failed to control the motors.

Anyway, i tried using Atmel studio 4/5/6 but as these devices are not configured to work with this program, and the stk5000 or whatever it was failed to work for me, i asked around to see if anyone had a programmer, the nice AVRISP blue device MK2? as this worked. sadly no one was available, Thank you Chris for offering to borrow yours!!
in the end, my impatience got the best of me, and as i had prime on amazon, i decided to spend some more money and grab one for myself. Luckily it arrived on Saturday and the amazon delivery person left it on my doorstep.

I then spent the next 10 minutes making the correct cable to connect my Hobbyking Atmel chip programming tool to the 6 pin cable from the device, and e viola (??) plugged it in, got the hex file and BOOM! programmed!
plugged it into motor and RX and nothing...

After testing, i decided to get the Spectrum hex file from the programming thread and BOOM downloaded (love having the correct tool for the job!) Connected it all up and Whhirrrrrrrrrr YES!!! we have movement and speed control!

After an ebay purchase week before last, i am now the owner of a 24v HIWIN electric actuator, the 100mm stroke at 25mm/s one. Love it, it is 40mm wide so fits nicely between my 2 halves of my robot, and the idea is that i can use this for a lifter if i feel the need to do so if the axe doesnt work out. I still have to build the plates for the axe, and am looking to get some chain sprockets for this as apposed to gears and timing belt. Im hoping that the gear ratio im thinking about is still possible within the frame i have. It was designed to be ok, so hoping.

I was also thinking, that i could easily have the axe, flipper as replacement bitsv - heaviest setup will be the axe. But, i could swap them out if i needed. Then i thought, if i have a motor there onto gears, could i have a small spinning disk? hey why not. So first thing first...v get the axe sorted.
what i will do, is add on an extra 5 mm to the width of the gap in between, so luckily i do have to machine a new rib from 20mm anyway.

The hardox armour has been made for the back, not looking great but i can tidy this up. it was a bit of a faff as using slightly curved hardox taken from Hard-Ox shell, but i have been able to work with it.
The side armour one needs a trim back, and i did weld the other side, but as i didnt CAD (Cardboard Aided Design) it, i have got the sizes a bit wrong, so will have to angle grind the welds off again and rebend/shape/weld with the aid of cardboard templates.
the front wedge plates need to be cut and welded in place to the sides, and mounting points worked out drilled and sorted.

Then the base...
I been trying to get to our scrappy to see what titanium plate they have, but each time i go they dont have anything or its all been taken away. so have decided to go for 10mm HDPE as this seems to be a popular choice - any recommendations greatly received.
I cannot machine this on my current router, so im hoping to be able to modify it and make it bigger, or get it cut outside using a work contact. As this is 10mm and not the originally designed 6mm material, i will have to modify all the finger joints on the existing parts to get it to fit.

Wow... so quite a lot to do then.... Now i must sleep, and plan tomorrows lunchtime activities!

pictures:
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[Roboteernat]

Some more developments,

I finally decided on the axe mech transmission.
Originally looking at timing belt and gears in a 2 stage gear reduction. As I needed to order some bits for work I was able to add on some bits, my additional cost mind.
I decided due to the strength and how much these will be bashed, to go for chain and sprocket, hurrah! I decided to go for 8mm pitch and again the space requirements dictate a 2 stage gear reduction. 1:1.25 then 1:3.66 or something. Due to the location of he gears I have to do it this way meaning first stage is 8 tooth to 10 tooth just to get the space to enable the 2nd stage to get the centre of axe rotation in correct place.
Hoping that once the Portsmouth event is done, I can upgrade to brushless axe drive so my space can be managed better.

So finally I now have some sprockets on their way from BelringOnline and chain from simply bearings. Was the cheaper options then buying from single store, and simply didn't sell the correct pitch sized sprockets.

Will see about using my electronic esc or am Rc switch relay for driving the axe, shall see when it's here next week.

[Roboteernat]

My drill motor mounts

Sadly i missed the postie over the weekend, but in the end my parts didnt come then.
So today, UK mail tried to deliver the gears to my home address as i was out at woirk, will have to get them resent.

These parts being... my pulleys for the 2 stage gearing for the axe. I did hoiwever receive my chain to my work address so i have 5m of 8mm 'scooter' chain as it is commonly reffered to in these parts.

Im looking forward to getting the gears then i can progress with the axe mech.