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Rob Team Rotwang
Joined: 19 Jun 2004
Posts: 294
Location: Victoria
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Hydra~Rotwang Robotics~VIC
Hydra
Specifications
13.6kg Sportsman
12v 100w scooter motors
6 A123’s
18v Drill motor for drum
12v Condenser fan motor for saw
IBC for drive prototype A
320 amp speed controller for drum
Scooter wheels with belts
Tool steel drum teeth
V belt driven saw
10” saw
Stainless steel drum
Colson wheel friction drum drive
Welded steel tube frame
Aluminium, Polycarb, Stainless steel armor
DX6 spectrum radio
Spectrum BR6000 Bot receiver
What started out as a simple freshen up of old Minimower turned into a last minute total new robot to go to the 2015 Ipswich Nationals
Bit of back history, Minimower build thread
http://robowars.org/teams/rotwang/minimower/minimower.html
Some robots go on fighting until they're scrap metal, but Minimower earnt a bit of fame in his part in regurgitator video clip so really he should be retired alongside the likes of cake taker, powderpuff and kill bot while still recognizable.
https://www.youtube.com/watch?v=tTQ2Y5oC3q8
Original minimower was built to the old 12kg weight limit and ran on lead acid batteries
So obviously there was more we could do with lithium batteries and a 13.6 weight limit.
Looking back at minimower there's virtually no armor and we didnt expect to need much armor in this sportsman class.
Either way the wedge will be deleted for sportsman. So with the weight to spare, another active weapon can be packaged in there.
24th September 2015
Pile of parts
Matthews BMX bike pegs, just some of the natural resources used. Dad can almost build a robot from his work bench by grabbing from the massive piles of clutter.
Pile of parts a little more
First weigh in just a very tube frame
25th September 2015
Drums on. Stainless steel pipe with plastic end caps and tube inner axel, very 'Minimower'. now to work out where to hinge the drill motor to friction drive the drum.
Drum motor mounted now wheels lined up and set in place with temporary threaded rod to get it all straight. Using standardiesd Rotwang height blocks speeds up this process.
We’re safeway the fresh food people… Parts all weighed to give rough idea and we will have a couple of kg for armor.
Wheels on so drive motor can be set in place and now contemplating saw
26th September 2015
Another weigh in just as a drum bot would make a good drum bot just as it is.
Weapon motor mounted decided all access will happen from the bottom so captive nuts are added for future service.
Working back from the mounted weapon saw is attached with a bit of thought into deflecting the saw when it bends, some warning before cutting our own belt.
27th September 2015
Flipped it up side down realized it’s like a 3rd weapon or at least offers a whole extra attack strategy being much higher than the under cutter.
We wonder which side people will consider “the front”
Cut top armor to size. Aluminium is not something we use in the main featherweight competition but seems ideal here.
Looking at what to use for armor. Theres some shiny Aluminium checker plate we wouldnt use on a feather anymore but can support itself for top armor in this class. Some verious bits of stainless there. Decide to use the aluminium on the top (550gram) with pop rivets and weld some stainless on the side to give some strength and screw clear polycarb (450gram) on the bottom. That should cover us for most scenarios and is within the weight budget.
Weighs about 2.8 here before welding and a few little tabs to hold the armor.
Welding all the joins properly now with the mig
28th September 2015
All welded now weighing 3kg and decide on stainless for sides and polycarb for bottom tabs for polycarb to screw to are attached with captive nuts that is frame complete.
Found a place to hang frame to spray some silver gal undercoat
few coats of golden yellow gloss, something that will stand out well on camera.Now hang out to dry for tomorrow and armor will be welded to the sides.
29th September 2015
Stainless welded on the side
touching up the paint
shell complete!
30th September 2015
the red wheels arrived for the drum and got machined up
top view. riveted the top armor on, should be good and sturdy, they hold planes together well enough.
grinder didnt like cutting the tool steel. divided the drum into thirds and welded 9 teeth on, nice and sharp.
looking at electronics now, 'series A' IBC with Minimower scratched into the heatsink. Just borrowing it minimower.
1st October 2015
installed the 'on' light, somewhere its least likely get a direct hit with a hammer or saw.
found the packaging for the electronics isnt going to be quite so easy, thought it was roomier. trying a couple of combinations. ibc or scorpion and different battery packaging.
ibc is heavier and bulker but it lets the drives run at full power where the scorpion will limit it a little. thinking it could be set up to run both with the same connections so we have a backup.
2nd October 2015
Took a few trys to get this picture with the weight, kept forgetting to throw something in the basket haha. Weighed in at 13 530g and that's without the on switch thrown in and not counting wire and a few small things. so far nothing has been modified for weight. Thinking a bit can be taken off the length of the bolt/shaft on the saw weapon aswell as remaking the crush tube and spacer in aluminium. Also could go with the scorpion over the ibc.
Tested the drums speed with the tachometer. as its 100 rpm over we have to consider some options. limiting the voltage, limiting the radio, using a smaller wheel for the drum friction drive, or changing the motor.
3rd October 2015
Wiring and smaller colson driving the drum saved some weight and helped bring the speed down
Weight saving, remade these saw mounting parts in aluminium
Refreshing my memory on receiver options, easy to eliminate a couple the 4 channel ones, need 5 channels for saw, drum, flip, drives and flip function for drives. Either the hobbyking Turborix or Spectrum DX6. Turborix is cheap and has cheap small receivers and needs a software package to program it. The old DX6 is conveniently digital onboard interface but has receivers that aren’t available anymore.
Programing the controller. Playing around with the dual rate function and exponential. Not sure how rusty my driving is so I can maybe slow it down or adjust steering controls exponential to up the sensitivity for box rushing.
Final wiring, Velcro keeps it all in place and adds a bit of shock dampening
Trying various battery cell configurations trying to get the best packaging.
Using something like this, one of benders custom aluminium hardcase to use 2x3 cell lithium polymer.
Final weight! Thought we should put a couple of bump stops on the sides to stop getting stood up by lifters and flippers. Thats the yellow thing balancing ontop there.
Basically complete now, just the bump stops for the sides and a few spares. Still got wiring to do on Minimower and Bender and some mods to Skeletor and tools to prepare and spare parts and getting the car ready for the drive up.
_________________
My combat robot
Robowars on YouTube
RotwangRobotics
Last edited by Rob Team Rotwang on Wed Oct 07, 2015 9:57 pm; edited 17 times in total
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Mon Sep 28, 2015 11:18 pm |
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