Barróg - Featherweight Lifter Build Diary

[Shooty]

So thanks to the Christmas season, I finally have enough time to CAD up my next FW and the second model of Barróg, one I'm dubbing "Barróg Doom" (name pun from "Dearg Doom" by The Horslips). I was debating creating a new build diary for this, but given how the description "Featherweight Lifter" still applies and how I'm quite proud of this build diary itself I'll stick to this one for now.


The cracking song I'm taking the name of the new machine from.

Barróg surprised me in a lot of ways, and after a year's worth of events I had gotten a lot about it tuned in. I had a sturdy, reliable drive, and a body design that seemed to absorb and deflect damage in all the right ways and areas. The one consistent issue with the design however was the weapon; it was slow, bulky, and never really grabbed anyone. This new design is essentially the same as the first iteration, but reworked to allow a Snake KOB-style grab-and-lift mechanism.


The new design, minus the inevitable weight-saving holes.

Design-wise almost everything will be the same. The base and walls are still 10mm HDPE and will still be mounted with barrel nuts. The drive will still be powered by four 12V motors with tapped 100mm plastic wheels, running on a 5S battery. The machine is still shares the same length and width as before, and the overall geometry will remain the same. I'll even be able to re-use the existing anti-horizontal wedge with minimal modifications. To figure out where to place the new height, I just looked at where the gouges from previous verts stopped, then went a cm or two higher, a very scientific method. Weight-wise, it should be looking far healthier than Barróg once the gears and sprockets bought from beltingonline.co.uk are machined, the machine doesn't gain too much extra weight with the new setup compared to the linear actuator, and losing some of the material on the top goes even further with this. The smaller size and weight allows me to also run with rollcages on the sides, so the machine should now finally be able to self-right from any angle.


A look at the insides.

The lifter operates similarly to the FW lifters used by Snake (CHN) and Mantis (UK). Upon power, the lifter gear on the clamping arm comes down. Once it catches, the teeth engage with the main lifter gear, and both the clamping arm and the lifting forks raise up. This allows for Complete Control-style lifts while only requiring one source of locomotion. I'm planning to use some hollowed out 25mm steel pipes for the main axis of lift, and have already reached out to Giles Ruscoe (builder of Mantis) about his methods.




My mockup of what the sprocket mount should look like. Needs to be tight, as given threads are holding it on to the drill motors, any gaps will cause unscrewing and a loss of essentially half the power.

The power for the lifter will be provided by two Argos 14.4V motors opposite to each other on a sprocket, similar to the system of transmission on the FW bot Nessie. They will be held tight in together by a system of tapped hubs and reverse threaded screws. Using the Argos drills gives me a system that's affordable, easily replaceable with the parts ready to buy almost anywhere in the UK and Ireland, and come with a built in torque limiter, which should protect my parts from destroying themselves at the peaks of their output. It goes from a 12T sprocket to 29T, then from a 16T spur gear to a 48T, a reduction of 206.19:1 per drill motor which should provide in theory a total lift of 22.185kgf/m, plenty to lift a standard FW, and a lot quicker than the previous method to boot.


A better look at the systems of sprockets and gears.

I still intend to run the original Barróg from time to time, and will bring it with me to Robodojo later in January (hopefully I can fix the linear actuator in it before then). I am hoping to get this new build finished before Extreme Robots Bolton this July, with the intention of getting any kinks sorted out before Insomnia 65. If anyone has any thoughts on the design then that would be appreciated, I'm keeping most of the complex stuff in the weapon this time round, so the rest of the build should be easy in comparison. Some methods of securing the main lifter gear to the axle pipe would also be very useful. I'm also looking for a way to mount the green HDPE wedge that maintains some of the springiness from the linac version, as I believe that was key in letting it survive the blows the way it did. Suggestions for that are welcome as well.