RogueTwo Robots

[RogueTwoRobots]

I'm classing it as a unique device, hereby referred to as a 'smashy smashy'.

On that note, I'm just gonna leave this here

[RogueTwoRobots]

Update

Managed to give a little bit of attention to Scar today for the first time since getting it. First job was to remove the inner box-section 'structure' that was there, presumably for the benefit of the old components that used to reside in it. Since it's getting a complete revamp in terms of its internals, they had to go. They were welded in so I predicted much use of angle grinding and swearing (it's quite tight!), but I quickly realised that the welds weren't that strong and was able to just bash each piece out with a hammer. Easy as pi and much more space now:

scar_build (7).jpg

I then started messing about with possible drive setups. The two motors I have to hand are a 300W scooter motor and a Bosch 400. After some deliberation, it's looking like the Bosch is the more viable option (unless I come across better options). The plan is to run it on a single-stage reduction, very similar to Tanto Jr/Scot-Bots housebot, although I'll maybe gear it for more torque and less speed. Might need to make some wheels from HDPE and cut/screw the go-kart tyres on though as they're currently not best set up to run on a shaft.

scar_build (8).jpg

If you click on the picture to enlarge, you may or may not be able to see the wheel shaft sticking through at the back, just below the welded nut. On each wheel, these are hollow and I'm assuming they just went over the wheelchair motor shaft and got pinned in place. But I'm planning on mounting a solid/fixed shaft on either side of the chassis, with wheels running on bearings. There's no scope within the current wheels to do this hence the possible need to cut and paste.

That's all I managed today, so now I need to source another Bosch 400. Used to have a second one as well - got them when they were going cheap on eBay - but sold it on a few years ago. D'oh!

[RogueTwoRobots]

Update

Kinda forgot about this thread now I've got a FB team page on the go, time to bring it up to speed.

Spent some time over the past few weeks building a robot around the axe module I made pre-champs. Rather than try and get it all in weight when attached to Carcinus, I figured it would work better as its own machine and it means I can tick axe-bot off the list. Back when the Bosch 400 was intended for it, the name I had was Grond (a LOTR reference), but now it's called Onyx. No particular reason other than I think it sounds cool, and no connection to the mineral.

This is how it looked from the back shortly before it appeared at a Scot-Bots talk a couple of weeks ago:



Since then, the Scorpion XL has been transplanted into Carcinus after I blew up one of its ESCs by running it on too high a voltage (Mtroniks, 12V max) and Victors have taken its place. The LED strips have also gone after I forgot that they too only operated up to 12V and proceeded to plug them into a fully-charged 5-cell lipo pack. The receiver, RX battery and link all now reside in the front right-hand section.

Filmed a test of it today which had mixed results. Overall, the robot is very nippy and, although the axe won't cause much damage, it's really fun to play with and self-rights the robot nicely. The Victors don't offer nearly as much precise control as an XL, something which I've never noticed previously, so will look at getting another Scorpion or some TZ-85s somewhere down the line. The axe gearbox also jammed up as a result of the pins coming out. The same thing happened at the Scot-Bots talk and although I repaired it, it wasn't enough. I reckon I can redo the repairs more sufficiently for it to work for sustained periods, but if it's going to be a persistent problem, I might look at making the transmission two-stage, with the first stage being a timing belt and pulleys from the motor, just to try and reduce shocks. Probably won't happen before Edinburgh though, so will see how it gets on then.



Need to grind some bits off the chassis somewhere too as something's fouling on the floor, hindering the drive a bit.

[Bodge Job]

Looks good!

[Gaseraki]

Indeed, is looking nice. Also lookign forward to seeing more of scar

[RogueTwoRobots]

Update & Event Report

So I managed to get Onyx finished up a few days before the Robots Live Edinburgh event, with some last minute spare modified drill shafts made for the axe as I expected a few failures. This is how it looked prior to the event:



The curved scoop is all 5mm steel; took a bit of work and not quite as neat as it could be but it's solid so I'm pretty happy with it. Also shortened the axe arm and curved the head a little as it looked a bit bland beforehand.
All was working well in the run-up to Edinburgh but when moving the arm after arming-up in the first fight (and even before the fight started) the axe jammed. As I suspected, the pins had failed again so I just ran it without the axe in the first fight.

The drive is incredibly fast but I struggled with controlling it a little (too used to the precise nature of the XL) and ended up smoking a motor by the end. Swapped that out during the break but ran out of time to repair the axe, so went into the second fight, again weaponless, and got flipped pretty early on. Had more drive issues but it was just with reverse-threaded screws coming loose so I sorted that out with a bit of Loctite. Finally got to repair the axe but turned out that the grub screws were looser than I though so, although the axe could fire, the torque limiter was kicking in when the robot was upside down so it still couldn't self-right. Eventually sorted it and got it all working well for the fourth and final fight and got a few full-strength hits in before the axe mysteriously started getting really slow. A quick look inside revealed that the screws holding the motor and its mounting plate on had come loose, so the gears weren't meshed properly and had been slipping.

It's an easy fix which will get done, but I'll be looking at fitting the 300W scooter motor in somehow now. The drill motor just isn't designed for the punishment of an axe weapon and will just be a long-term hassle if I persist with it. Weight will be tight using the scooter motor but it's currently at 12.9kg without any form of weight-saving having taken place, so I'm hopeful that I can manage it somehow. The increased reliability will certainly be worth it.

For once, Carcinus was pretty low-maintenance and only had to have a little one-minute repair made to the actuator between shows. Still ended up in the pit a couple of times but I think that wasn't directly connected to my dad's driving this time!

Once I give both machines the necessary TLC, I'll work out plans for heading forward. Not got any more events down as definites this year, but got a couple I'd like to get to, circumstances permitting. Got a lot of work to do on Scar, want to get a couple of beetles up and running and Drumroll - which has been in pieces since the champs - needs rebuilt once it's had a bit of a redesign. Also got that grabber/lifter waiting to be done on top of any Scot-Bots stuff that'll need doing over the year. Eeeny-meeny-miney-mo!

[Gaseraki]

Cheers for the report. Love how little things can turn into anoying problems. Its looking great and I think a 300 watt motor will do it good. Not for damage but for flair.

[shakesc]

Looking good. Enjoying these axe bots

[RogueTwoRobots]

Update

Started looking at swapping out the axe drill motor for the 300W scooter motor. Finally managed to get the existing sprocket off the motor (turns out I was grabbing the wrong bit) so first step was to see what the damage would be:



Lose 900g at the same time as fitting a chugging great big (and more powerful) motor? Challenge accepted!

Next step was working out how to try and fit it in to the existing interior layout. I thought a lot of stuff would have to be rejigged, including the drives, but simply by cutting one of the bulkheads in half (saving 370g) I was able to bolt it in at the back.



Weight distribution still seems good; the motor weighs 2.2kg and the 5mm steel scoop at the front is probably a similar amount, so the kilos are well spread over the drive wheels. That's all I managed to get done on it today (forgot to take a picture with the motor fitted) but I did have a cheeky little test of it. Here it's running on a 5:1 ratio at 18.5V(ish), so theoretical rpm at the axe shaft should be around 385rpm, not taking losses into account, so almost four times as fast as the old drill motor setup. It's just a short video as I was doing a direct connection to the battery and promptly soiled myself (not literally) when it fired.



I'm particularly loving the air time it gets, which is more noticeable in the slow-mo replay. I think when it's fully under RC again, it'll be crazy when it fires, which will look immense. Not fussed about damage, although I expect it to do more now, but as long as it has epic spasms, I'm happy. Just taking wagers now on what will break next. Already eliminated the first source (drill motor) so I expect either the chain to be a regular snapper or the sprocket on the motor to strip teeth or break its welds (not much boss left on it).

[Gaseraki]

Great improvments so far. Best of luck shaving the 900 grams