www.robowars.org

RoboWars Australia Forum Index -> Builders Reports

Zenghiaro - Slightly Evil Robotics - SA
Goto page Previous  1, 2, 3, 4, 5  Next

Post new topic   Reply to topic
  Author    Thread
evil_steve



Joined: 06 Sep 2015
Posts: 301
Location: Adelaide, SA


 Reply with quote  

Success! Plan B for the lifting mechanism (set screw hubs with a flat edge filed onto the shafts) seems to work well. Here it is lifting a 7kg towbar (which was the heaviest object of appropriate size I had readily to hand).

Post Tue May 24, 2016 10:53 pm 
 View user's profile Send private message
evil_steve



Joined: 06 Sep 2015
Posts: 301
Location: Adelaide, SA


 Reply with quote  

Well, apart from replacing an ESC I stupidly wired in backwards, Zenghiaro is done and ready for Vivid.

Robot: Zenghiaro
Class: Featherweight Sportsman
Weapon: Dual motor electric lifter
Weight: 10.6kg





Unfortunately the link mount Nick so nicely printed for me doesn't quite fit either of the spots I was going to put it, so I've gone for a recessed switch for now, hopefully that doesn't come back to bite me. Just another thing for the redesign/rebuild post Vivid I guess!

Post Sat May 28, 2016 2:09 pm 
 View user's profile Send private message
Valen
Experienced Roboteer


Joined: 07 Jul 2004
Posts: 4435
Location: Sydney


 Reply with quote  

that switch will probably get switched when your bot gets hit
_________________
Mechanical engineers build weapons, civil engineers build targets

Post Sun May 29, 2016 10:08 am 
 View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger MSN Messenger ICQ Number
James2



Joined: 07 May 2015
Posts: 115
Location: South Australia


 Reply with quote  

You could print a locking block.

Post Sun May 29, 2016 10:38 am 
 View user's profile Send private message
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


 Reply with quote  

The simplest thing is to put in a screw from the side that blocks the switch from turning off.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Post Sun May 29, 2016 11:13 am 
 View user's profile Send private message
evil_steve



Joined: 06 Sep 2015
Posts: 301
Location: Adelaide, SA


 Reply with quote  

Yeah, I might do something like that for now.

Post Sun May 29, 2016 11:16 am 
 View user's profile Send private message
Ondray



Joined: 06 Jul 2015
Posts: 139
Location: Newcastle


 Reply with quote  

That is awesome and looks solid. The 'eyes' add some nice intimidation.

Post Sun May 29, 2016 7:35 pm 
 View user's profile Send private message
evil_steve



Joined: 06 Sep 2015
Posts: 301
Location: Adelaide, SA


 Reply with quote  

Thanks, I figured if I'm going to name it after an animal (kinda), I should give it eyes. It's funny, while the design has evolved a hell of a lot from what I originally envisioned and there are things I'd do differently if I was to start over again, looking at it completed I'm happy with how it came together. How effective it is ... we'll see.

Under both the "evolved design" and "do differently" categories: I changed wheel size but didn't shift the rear "axle" line far enough backwards for Zenghiaro to self right the way I had hoped. It can however do it with a bit of break-dancing. I didn't mess up the side armour though so it can also drive inverted.

And here's the power switch restraining bolt (thanks for the suggestion Nick, and I promise I'll use the removable link it either a rebuild or my next bot!), which I guess also acts as another safety mechanism outside the box.

Post Sun May 29, 2016 8:44 pm 
 View user's profile Send private message
evil_steve



Joined: 06 Sep 2015
Posts: 301
Location: Adelaide, SA


 Reply with quote  

Alright, some thoughts post Vivid (sorry about the length).

* The chopping-board chassis/armour this (mostly) held together a hell of a lot better than I thought it would. The main failure was on the most unsupported bit of armour (front/top), under relentless battering from Repent. Unfortunately that then exposed my lifting motors to said assault, destroying both of them. However, the duct-taped on replacement piece (which was actually thinner but I think better supported) then held up really well under the same conditions in the rumble, so I think it's got potential. Taking Zenghiaro apart the base plate has broken away around the barrel nuts on one side this must have happened in the rumble as it wasn't there before then (I suspect getting thrown twice by Citizen Flips had something to do with it), although I had actually cracked around one of them slightly during construction anyway. Either way, it was still holding together by the end of the night, I'll just try and be more careful when I make the new base plate.

* The drive-train I have mixed feelings about this. In testing and then the first 10 seconds of my first match it was great, but then I smoked the left hand 85A ESC, with it fusing into full reverse (I thought at the event that the front wheel had slid inwards and jammed against the chassis, but on reviewing video of the fight First Pick actually got a good hit on that wheel which is probably what jammed it). That made the rest of the fight interesting, but more than that it also meant that I had to drop to 2WD for the rest of the event as I only had 30A ESCs as spares. This drove generally ok each fight but lacked any pushing power and was slow to turn as it was fighting the friction of the front wheels. Overall I like the 4WD platform, and the redundancy of two motors a side was nice. Unfortunately I'll have to wait until I can get any more 85A ESCs to get it running 4WD again.

* The wheels these had major issues. Firstly, they would slide inwards along the manifold nuts (which I initially thought was what caused the jam against the chassis in the first fight). Secondly, at least one a fight would crumble around the nut, so I'd end up with minimal drive on that side by the end. Unfortunately the overall design needs wheels that diameter (125mm) to be able to drive inverted and self-right. Seeing what others have done and talking to them I've had some thoughts as to how I could improve them. Other options are trying to make my own wheels (tricky without a lathe), find some other 125mm wheels, or use standard red wheels and hope I don't get inverted (although that might also require a change to the chassis).

* The lifting mechanism had some issues and then got destroyed, but was going to be redesigned anyway. Had enough grunt in the first fight to lift First Pick before it all went haywire (although I need to add outrunners at the front to stop tipping forward), but after that didn't really get a chance to do anything. The plan is to use a single motor/gearbox connected via chain to a live axle driving both lifting arms, I've already got most of the bits, just didn't get the chance to build it before Vivid. Although after seeing the size of other people's lifting motors at Vivid I'm worried that it's not going to be powerful enough. Depending on how it goes in August I might change to a beefier motor for next year

Despite all Zenghiaro's issues Owen and I both had a great time, and I'm also happy that I managed to keep getting it into the box in at least vaguely working order for all 4 rounds and the rumble, and that it didn't get counted out in any of them. I think Vivid was an awesome first event given that it was more of a demo rather than a competition. Everyone was very welcoming and helpful, and Owen's fight using the bot Steve lent him made his night. I'm already looking at accommodation/transport options for Nationals, just need to find time to do all the above fixes (and hopefully make a second bot as well).

Some photos
Zenghiaro ready for it's first fight:


Then after being brutally attacked by Repent


Duct-tape FTW! Zenghiaro's final form:


Owen with the giant-slaying Saw Thing:


Damage from the rumble and/or my poor drilling skills:

Post Thu Jun 09, 2016 8:39 pm 
 View user's profile Send private message
leithal_weapon



Joined: 06 Jun 2016
Posts: 35
Location: Canberra


 Reply with quote  

I wonder there is a way stop over current from stalled motor, frying the ESC. Im surprised ESCs don't include this anyway, overcurrent protection circuit is very simple.

Post Thu Jun 09, 2016 10:24 pm 
 View user's profile Send private message
seanet1310



Joined: 08 Nov 2006
Posts: 1265
Location: Adelaide


 Reply with quote  

Great to hear you had fun. See you with an improved bot in a few months.

quote:
Originally posted by leithal_weapon:
I wonder there is a way stop over current from stalled motor, frying the ESC. Im surprised ESCs don't include this anyway, overcurrent protection circuit is very simple.


In an interstate comp some of use (well at least me) would rather go all out than in the arena than have a protection circuit that keeps kicking in. Of course this is a double edge sward as you may loose the ESC for the rest of the match or possibly the event.

Been done before. Some of the ESC came with various protection, rather annoying (remember the Sabertooths for the people around half a decade ago?) Scorpion XXL was not too bad and I think had some level of current protection.

Not current limiting but didn't the V2 Botbitz with programming box have the option for temp protection?

Leithal, perhaps you could look into designing one for people to use if they wish. I have no doubt there would be a market both in full combat for some and for practice/trials as well as demos or 'fun' events. An external circuit is something else that could go wrong in the forces of combat.


Some of the bushless ESC have some in built sensing for those a little more electronics/programming literate to mod as a stand alone option but would take a bit of time.

May have been the 4WD as TZ85 are reasonably robust in a stalled drill although I have melted all the SMD off one before.
_________________
Remember to trust me, I am an Engineer.

http://www.youtube.com/watch?v=rp8hvyjZWHs

Post Fri Jun 10, 2016 7:20 pm 
 View user's profile Send private message Send e-mail Yahoo Messenger MSN Messenger
marto
Experienced Roboteer


Joined: 08 Jul 2004
Posts: 5459
Location: Brisbane, QLD


 Reply with quote  


quote:
overcurrent protection circuit is very simple.


No but its called a Ragebridge if you want it.

In theory simple in practice not so much particularly with what we do with them. Cheap/Simple/Reliable pick two.
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Post Fri Jun 10, 2016 9:25 pm 
 View user's profile Send private message Send e-mail MSN Messenger
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


 Reply with quote  

Back in the day we all had cheap and reliable current limiting - NiCad batteries! Laughing I 2nd Steve's suggestion; the Ragebridge is a very well built and compact dual ESC and its hard to find anything better for Featherweight and Sportsman bots
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Post Fri Jun 10, 2016 9:44 pm 
 View user's profile Send private message
evil_steve



Joined: 06 Sep 2015
Posts: 301
Location: Adelaide, SA


 Reply with quote  

After Sunday (and also from reading Charles' blog) I'm tempted, if only we had a local distributor Very Happy

I had hoped that the 85A ESCs would be ok running two drill motors each. On the one hand I smoked that one pretty early on in my day (which sucked), but on the other the 30A ones coped fine with one drill each the rest of the event, so I'm not sure if it's likely to be a recurring issue or just dumb luck.

I was planning on getting some more 85A ESCs before August and hoping it doesn't happen again - if it does I'll probably get a Ragebridge! Ideally I'd like to rebuild Zenghiaro with 1 better quality motor a side driving 2 wheels each via chains/timing belts, but that takes more fabrication skills/tools/time than I have. The only other thought I had was splitting the receiver connections to have 2 ESCs in parallel a side, each running 1 motor - but I have no idea whether this is feasible/sane.

Post Fri Jun 10, 2016 10:13 pm 
 View user's profile Send private message
Ondray



Joined: 06 Jul 2015
Posts: 139
Location: Newcastle


 Reply with quote  

I read about the ragebridge before - but didn't realize it can run two motors! This makes me much more interested as I want to 4WD my bot and this would let me run the whole drive off one ragebridge...Even though according to 'ohms law' the TZ85's should do as well.

Maybe a group buy to get MOAR RAGE?

Post Sat Jun 11, 2016 12:06 am 
 View user's profile Send private message
  Display posts from previous:      

Forum Jump:
Jump to:  

Post new topic   Reply to topic
Page 4 of 5

Goto page Previous  1, 2, 3, 4, 5  Next

Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

 

Last Thread | Next Thread  >
Powered by phpBB: © 2001 phpBB Group
millenniumFalcon Template By Vereor.