Questions:
1.I plan to make the connecting tube of the spinner out of thick aluminum plate (cutting concentric circles)instead of looking for tubes of the right size. Do you think cutting 3cm aluminum plate would be reasonably easy?
2.I plan to keep the dual 2.5kw weapon motors on board, so with the drive motors the bot will have about 5.5kw of power consumption (peak). I'm aware that average power throughout the whole match would be lower than that, but since I have no actual experience I have no idea what fraction of peak power a robot like this usually takes. (I previously thought this fraction would be 0.5, but yesterday a few of my friends said as low as 1/3.) I wonder what fraction you guys tend to get during matches.
Tue Apr 18, 2017 3:44 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
Using a couple of thick plates for the connecting tube is possible but the finish from water jetting or laser may not be that great and cleaning the parts up on the lathe will add to the expense. Also, the bolt holes may not be very accurate in that thickness. A better and probably cheaper way to do it is to start out with a round bar and bore it out to the required diameter; the part will be stronger, have more accurate dimensions and possibly cheaper too.
Its difficult to measure average current consumption but I can say that Mr Mangle uses up 3/4 of a 4.25 AH, 6S Lipo in a full length match. Current peaks are over 150A but the data logger shows they are short, only 5 seconds before the current is down to around 80A and then full speed current is 40 to 50A. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Apr 18, 2017 4:46 pm
MoonSet416
Joined: 25 Sep 2016
Posts: 436
Location: Sydney
OK I see... Thanks for the info.
BTW what data logger are you using? An Arduino?
Tue Apr 18, 2017 6:28 pm
MoonSet416
Joined: 25 Sep 2016
Posts: 436
Location: Sydney
Also I would like to ask how hard is it to machine a timing pulley (by machining it I mean I will buy one online, but then I need to let the machine shop drill some screw holes and maybe make a cut in it)
Tue Apr 18, 2017 7:08 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
That would be very easy to do. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Apr 18, 2017 9:14 pm
MoonSet416
Joined: 25 Sep 2016
Posts: 436
Location: Sydney
Ah I see... Thanks Nick.
Wed Apr 19, 2017 2:04 am
MoonSet416
Joined: 25 Sep 2016
Posts: 436
Location: Sydney
So the latest version looks like this, basically a mix between the last two versions.
Wed Apr 19, 2017 2:05 am
Dylon
Joined: 09 Nov 2006
Posts: 631
Location: Newcastle, NSW
I feel for vertical disk spinners to be successful they need some kind of way to deal with horizontal spinners as they love 90 degree angles which well you kinda need to support a vertical disk.
If you look at demon for example the whole rear armour is a harden steel wedge, perfect for dealing with other spinners.
I mean there aren't very many horizontal spinners in Australia but the off chance you have to fight one you need some way to defend yourself. _________________ Barton Robotics Youtube Channel:
https://www.youtube.com/user/dyl30
Yeah a countermeasure for horizontal spinners is very important (who knows if I will bring this machine to other places, and even in Australia there's decimator).
I think since I already have a steel angled front wedge I could potentially make an alternative vertical bar weapon. However this solution has the problem of needing time before a match to change the weapon blade, how long is the prep time usually?
EDIT: The reason I would try to avoid a steel back wedge is that it would make the top cover and side armor harder to attach (it's probably gonna be 5mm thick, but I wish I can use m6 screws for armor.)
Wed Apr 19, 2017 2:42 pm
maddox
Joined: 21 Dec 2006
Posts: 786
Location: Belgium
I would reconcider the way the cutouts in the ali bulkheads are oriented/shaped.
Now those are parallel and trough the whole sheet.
I would make those more like this
Wed Apr 19, 2017 2:47 pm
MoonSet416
Joined: 25 Sep 2016
Posts: 436
Location: Sydney
Yeah you're right, parallel cutouts will decrease the resistance in certain directions. What do you think of cheese grater patterned holes? (Pockets are a bit hard to do because I would like to keep the overall cost down.)
Wed Apr 19, 2017 3:13 pm
Dylon
Joined: 09 Nov 2006
Posts: 631
Location: Newcastle, NSW
Doesn't necessarily need to be a steel wedge, was just an example.. just think what is the scary part of a horizontal spinner and how do I stop it being scary. _________________ Barton Robotics Youtube Channel:
https://www.youtube.com/user/dyl30
Thx Dylon, that's a good idea. I once thought a wedge was the only way.
Fri Apr 21, 2017 6:15 pm
MoonSet416
Joined: 25 Sep 2016
Posts: 436
Location: Sydney
Progress up until now:
Added top and bottom cover.
Added missing screw holes.
Changed lightening hole pattern.
Feel free to leave your comment!
Sat Apr 22, 2017 1:55 am
MoonSet416
Joined: 25 Sep 2016
Posts: 436
Location: Sydney
Question: How did you guys determine your screw hole depth? Also I wonder if a screw hole with thread through its entire length is made differently from a hole with only partial thread.
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