www.robowars.org

RoboWars Australia Forum Index -> Builders Reports

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

Post new topic   Reply to topic
  Author    Thread
evil_steve



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


 Reply with quote  

Well, I'm now the proud owner of a cheap ebay winch, and it's rather a chunky thing. My current plan is to bodge it onto the current Zenghiaro chassis for Canberra, then redesign something around it properly for Sydney next year with a wider and shorter wheelbase (unless I decide to join the brushless master race)

It kinda fits. I'll probably end up going with just the one lifting arm in this configuration



The current bearing support sidewalls will have to go, and I'll go to the red Bunnings wheels (as invertability is impossible anyway without lowering the chassis (which would mean completely thinking how the motor mounts attach)). Even then I'm a bit worried about how far out the pot will sit on it's mount, hopefully the rejigged side armour can protect it.

Post Thu Jun 23, 2016 12:33 am 
 View user's profile Send private message
Nick
Experienced Roboteer


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


 Reply with quote  

Welcome to the winch club, now you can see why I am going through all the effort to replace the motor - the original one is huge!

How about mounting the other lifter arm on the other side of the drum?
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Post Thu Jun 23, 2016 12:47 am 
 View user's profile Send private message
evil_steve



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


 Reply with quote  

That's a good thought - might see how I'm going with weight but also with time - June-August is the busiest part of my year at work, so I'm not actually sure how much time and energy I'll actually have to work on this. Hence the plan to bodge something together now then work on it leisurely over summer Very Happy

Looking at what you're doing with the winch really makes me wish I had the skills/equipment to do something similar though, I like the way you've adapted the output from the gearbox, although I'm curious how you've attached the shaft - surely it's not just press fit?

Post Thu Jun 23, 2016 9:22 am 
 View user's profile Send private message
Nick
Experienced Roboteer


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


 Reply with quote  

Don't worry about the skilz and gear - my first bot used wooden motor mounts and the best tool I had at the time was a drill press. The big output shaft will, in fact be a press fit in the lifter arm but it doesn't exert any torque on the arm, its just there to keep everything aligned, support loads and take strain off the diecast ring gear. If you look at the lifter arm render, there is a circle of screw holes around the central axle; they will hold the arm to the ring gear and transmit all the lifting torque.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Post Thu Jun 23, 2016 9:43 am 
 View user's profile Send private message
evil_steve



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


 Reply with quote  

Oh, that makes sense, that's clever. If it works well I might try to do something similar down the track Very Happy What diameter is the big output shaft?

I mostly really enjoy finding ways to use the limited tools/materials I have to make stuff, it's just every now and again I come across a problem and/or see a solution on line and wish I had a lathe or whatever. Then I just come up with a shoddy alternative using inappropriate tool use and all's good

Post Thu Jun 23, 2016 2:56 pm 
 View user's profile Send private message
Nick
Experienced Roboteer


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


 Reply with quote  

The support shaft is 3/4" - the first thing I found in the spare parts bin. 12mm or 1/2" would probably be fine for a sportsman.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Post Thu Jun 23, 2016 4:02 pm 
 View user's profile Send private message
evil_steve



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


 Reply with quote  

Well, as I've said in another thread I've decided not to use the winch motor/gearbox in Zenghiaro, partly because of how it would change the whole look/design of the bot. Instead, I'm planning to use a two speed drill in low gear, with an additional 3:1 reduction using chain/sprockets.



This lifting mechanism is starting to take shape. There will be another support for the 8mm shaft on the other side of the large sprocket. Part of the plan this time around is to make it possible to take the whole lifting mechanism out of the bot for repairs without having to take off all the wheels and sides.

Post Thu Jul 21, 2016 10:59 pm 
 View user's profile Send private message
evil_steve



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


 Reply with quote  

Now Rusty is done I'm focusing on the rebuild of Zenghiaro.

The new baseplate with 6.5mm holes drilled for the drive motor mounts. After messing up a few on the initial build I've worked out that countersinking them with a 12mm bit run in reverse works well.



My chain seems a little ... flaccid. I mocked it up using some plastic chain that I ordered with some of the #25 gears, that seemed to fit OK but even with half links I couldn't get the length of the metal chain right.


The mostly finished lifting mechanism.


Complete with ghetto chain tensioner! When I googled "DIY chain tensioner" someone was using garden hose over a plastic clip, I figured a pipe clamp would give it some adjustability.



I've cut and drilled some adapter pieces so I can use the same lifting arms. I'm so glad I got in to Aldi early last weekend and got a cheap drill press, it's making this so much easier.


Tomorrow the plan is to drill all the other mounting holes in the base plate, and replace the front/top armour. If I had time I was going to redo some of the other pieces with non-critical damage, but now I'm figuring on just leaving the battle scars.

Post Sun Aug 14, 2016 9:09 pm 
 View user's profile Send private message
evil_steve



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


 Reply with quote  

Well I finally managed to get Zenghiaro back together so it's ready for the weekend. Haven't properly tested the lifting mechanism yet (I'm sure that won't come back to bite me ...), it goes but I'm not convinced it's geared low enough to be effective. Oh well, gotta keep rebuilding these things better Smile

The new internals. It's a much tighter fit than before with all the excess wiring, but that just saves me having to add foam.


All ready to be loaded into the car for the long trip tomorrow.

Post Tue Aug 16, 2016 11:38 pm 
 View user's profile Send private message
Ondray



Joined: 06 Jul 2015
Posts: 139
Location: Newcastle


 Reply with quote  

Yeah cheap mini drill presses are awesome! This is looking good - hopefully we get to face off this event.

Post Thu Aug 18, 2016 11:44 pm 
 View user's profile Send private message
evil_steve



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


 Reply with quote  

Ok, time for me to do another overly-wordy post-event write-up for Zenghiaro! I've also done one for Rusty in his thread (I know a lot of builders do combined threads but when I started out it was difficult/intimidating to read 500+ page build threads (I'm looking at you Nick Smile ), so in case any future builders are crazy enough to read my threads I've decided to keep them separate). Nationals and Big Boys Toys was a blast, we all had a great time and despite the long drive over and back are keen to do it all again next year.

Overall I was very happy with how Zenghiaro went. It won 4 fights, lost 2 or 3 (honestly, I lost track, I thought it was 3 but only have footage/memory of 6 fights), and held it's own in the rumble despite a non-functional lifting mechanism. The cutting-board chassis once again held up very well, this time with some scratches and nicks (with a large one from Beserker to one of the wheel guards) but no more than superficial damage, and after I more carefully drilled it this time around the baseplate didn't crack from being thrown again by Citizen Flips in the final rumble. When the wheels weren't falling off the 4WD system worked well with plenty of pushing power and it was a blast to drive. The Botbitz ESCs worked flawlessly (although I'm tempted to buy and try out a Ragebridge anyway, probably in a new bot, given the current sale).

Two things need rethinking/redesigning again though:

- The wheels. These were somewhat better (especially after I changed the washers around after the first fight with Warboy) and the wheels were lasting 2-4 fights (rather than 1-2 at Vivid) but they still were a pain. I'm still deciding whether I'll try Ondray's method of attaching them or try a different wheel completely (or, when I'm feeling completely mad, I consider making my own). I'm a bit stuck by wanting to keep it invertible (which was very handy in the rumble when the lifter wasn't working) and thus needing 125-130mm wheels, and by the decision to directly attach to the drill motor shafts with very little clearance (if I'm not careful they rub on some of the cutting board in spots, especially if I put one on backwards like I did towards the end of Sunday. It still drove fine in the rumble though). I did like the new reverse threaded screws I used this time instead of the crappy ones which came with the drills I bought them from here for those I promised to link them to.

- The lifting mechanism. Again, an improvement from Vivid but not great. It had a bit more power (and was able to get a few good lifts in, especially to put Disassembler on it's side for it's first ever win) but still probably needed to be geared lower, and it was too easily disabled. I think the latter was a combination of a few issues the set screw on the weapon shaft sprocket kept slipping back despite copious loctite +/- a second set screw up it's ass, which allowed it to slip off the flat I'd ground on the shaft and the sprocket to rotate freely. On thinking about it post event I wonder if the lack of limit switches contributed with the speed of the lifter it would thwack into the baseplate or drive pods at either end of travel and as the clamping hubs holding the arms to the shaft held tight the set screw on the sprocket was the weak point which gave. The bearings I was using (and the set screw hubs to hold them in) certainly didn't help they kept sliding out of position and just sitting on the now-loose shaft. I'm playing with options for a new mechanism I'm looking to keep the chain and sprocket but either drill a divot into the flat of the shaft (as suggested to me at the event) or try and find a proper d-shaft the right diameter/length. Not sure what motor I'll use, trying out a few and (foolishly) hoping to actually find time to test/adapt whatever I decide to run with. I'll probably ditch the bearings and either use bushings or even just plain holes in the cutting board supports (one of them had an extra support doing this and it was the one spot that didn't have issues). I'll almost certainly put in limit switches this time around (either doing the diode/switch thing or using this ESC ), and tweak a few other things (I should really recut new lifting arms with better geometry for a live shaft, and I plan to thicken the bars between the arms slightly, as the front one especially was too easily bent).

I'm not sure if I'll be able to make the Sportsman's Cup later this year (will depend on dates and work) but the current plan is to bring Zenghiaro and a second sportsman entry to Vivid +/- Nationals next year.

Pictures:

Our pit table (early on, before it got messy) and experienced pit crew.



Zenghiaro ready for it's first fight.


Post the fight with Beserker, the most damage it took all event.




I'm slowly editing the video of the fights I have and putting them up on Youtube, however given the quality of the footage Chris is putting up it's really a token effort Smile

Edit: meant to add a pic of Zenghiaro's lifting mechanism post event, showing the issues with the bearings.

Post Sun Aug 28, 2016 10:12 pm 
 View user's profile Send private message
Ondray



Joined: 06 Jul 2015
Posts: 139
Location: Newcastle


 Reply with quote  

That ESC is pretty cool - I should really look at a limit system for Hellamax. Especially given I'm operating the weapon off the left 'throttle' stick so it doesn't return to middle automatically for me. There was definitely damage as a result of pushing the arm against the frame. The only thing saving me I think is the electric window motors have a safety feature in them reducing that effect - I think they cut out on a solid stall, probably to stop kids from burning them out in a car door!

Also thanks for that link - all that stuff I said about drilling the recess for the washer is unnecessary with a longer reverse threaded screw! Leaving more material in the hub area, which should be a bit stronger.

Post Mon Aug 29, 2016 11:34 pm 
 View user's profile Send private message
evil_steve



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


 Reply with quote  

With Zenghiaro I've been running the lifter both times on the throttle stick but on channel 4 (side to side on that stick) so it's sprung. Worked ok with the slower mechanism but too hard to stop in time at Nationals. I'm planning to keep it on the same channel but use switches - might try the switch/diode thing before I order yet another type of ESC Smile

I've ordered some more of those screws myself - I had the 25mm ones before and was using them mostly with the wheels I'd already cut the hub shorter on anyway. I've ordered some more at that length and some 30mm ones so I can play with different washer thicknesses - I'll try the ones you were using and the big mudguard ones I had together. My plan for now is to keep using the white wheels but try your attachment method - I might change to the new Banebots T81 wheels/hubs down the track though.

Post Tue Aug 30, 2016 11:39 am 
 View user's profile Send private message
  Display posts from previous:      

Forum Jump:
Jump to:  

Post new topic   Reply to topic
Page 5 of 5

Goto page Previous  1, 2, 3, 4, 5

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.