Robots

Knightrous – Build Part 4

Posted on by Half Done Things

It bucket rain today and flooded most of my outside work space, so I retreated inside and worked on designing some parts to make in the future, like the weapon gearing.

The weapon first stage gearbox needs designed, so a quick bit of cad work produced this, the front bearing block which houses two 22x10x6 bearings and captures the ring gear.

Front side has sunken bolt holes to bolt the whole assembly together.

Putting the Banebots P61 4:1 parts into the front block.

Adding the main bolts

With this done, it’s time to design the rear block for the motor.

Designed this to center the motor with the ring gear, capture the motor screws and align everything together.

Bolting up the motor.

Ready to assemble the two halves.

Screws are oversized, but will order smaller ones once it is all finalised.

Printed out a shaft to work with the hex output for the Banebots.

It fits perfectly.

Next up I printed some HTD5 pulleys, a 16T for the motor gearbox and both a 30T and 32T to play around with what works best for the weapon end.

Running the calculations, the 32T is likely going to be the best one to use as it gives a neat 8:1.

Till next time.

Knightrous – Build Part 3

Posted on by Half Done Things

After tack welding the two half bots together, a few things became apparent.
1. It weighs 9.3kg already….
2. The weapon cannot be serviced as the weapon shaft cannot be removed in this position and there for cannot swap the bars or belts.

So I cut the existing mount and supports out.

There is actually a fair bit of weight in these two support plates, they are made from 5mm Hardox 500.

I’ve replaced the inner support of the chassis with some lightweight 20x20x2mm box section

The new weapon uprights will be made from 50x20x2mm RHS which will have a steel insert welded into them to support the weapon shaft.

These get a 25mm hole drilled into them.

A quick test fit to see what position will keep the weapon forward enough but also allow the shaft to be removed.

Some of the old chassis will be welded to the front like this (but not as much) to add some strength and armor to the front the robot.

Other than the fact that the robot is a little heavy, I noticed that the gas bottle chassis is rather oversized for what has to go inside.

I’m considering that I might cut 80mm off the front of it all to allow the center line of the gas bottle to butt up against the rear of the weapon upright.

This will compact the robot a bit, allow more armor to be added and also assist in self righting via the weapon.

Till next time!

Antweights at Convoy4Kids

Posted on by Half Done Things

The Wollongong crew held an antweight event at the Convoy4Kids charity event on 29th October.
I dug out some spares last minute and tried to put together Little Red Flipper (a prototype OG Botbitz GreenAnt kit).

It turns out I was missing a lot of parts…
The flipper servo.
The servo linkage.
The 2S batteries were dead.
The RX was missing.

First up was to print a linkage as I had the cad for it, however the servo I bought had a different spline. It took 8 goes to get it right for a press fit that worked…

The RX I found that would work in this robot uses micro leads, so I needed to remove the standard JR leads from the servo,

Micro lead attached.

I’ve not got a small iron these days, so doing this smaller soldering results in some burnt fingers and swearing. Need to order a smaller iron for this kind of work.

The BotBitz 10A’s needed the same treatment, getting a pair of micro leads.

Leads done!

And shrink wrapped.

With no 2S batteries, I substituted a 3S battery and prayed nothing exploded.

While trimming up the servo position for the flipper, I broke the flipper mechanism….

It was 10pm by this stage, so I designed to flick a message to a friend and see if he could print one from CF Nylon over night and bring it to the event for me.
I packed up the bot and all my gear, loaded the car and went to bed…

 

I arrived nice and early to find the event organisers setting up the arena.

I setup my gear and my static display of Scarlet’s.

Sitting there, waiting for the spare parts.

Soon other builders arrived and we started getting some bot appearing!

Pumpkin Wumpkin

Subdivide

Midnight Sun

Skelliwedge

Tossboss

Steelstorm 2 and Pokerface

Naughty Corner and Scissor

Spikeywacker

Mr Obvious

Deadline

The replacement flipper arrive and I assembled Little Red Flipper as quick as I could.

However I ran into something odd. The servo was only travelling 50-60% throw, which prevented the robot from lifting all the way up and self righting 🙁
The other issue was, it would not failsafe correctly. Despite being bound to the transmitter with the drives in a neutral position, the motors kept creeping. Not something I (nor safety) could allow.

So I sat down for the day and watched all the fights, before getting a chance to sneak Little Red Flipper into the end of day rumble for the non-destructive class.
Sadly it was flipped and could not self right and then ended up going down the pit :P. Highlight of the day, I was given the change to drive Tossboss in the rumble for the destruction class (Tossboss had just won the main event!) and was one of the last 3 bots standing!

There is a Youtube playlist of fights here: https://www.youtube.com/watch?v=8pwNudQRKW8&list=PLsvGjWpWp4gw241sEkaBS_2TH9emZeUNs

 

Smashing two bots together…. Knightrous 2.0 – Build Part 1

Posted on by Half Done Things

Once again, a new event has been announced and I’m shit out of working robots.
This event is the RoboWars 2024 Nationals, which will be Open Feathersweights!
The first time Opens will have been competing since 2019.

I’ve been kicking an idea around for a while for a new bot, an assymetrical, counter rotating, dual vertical spinner.
But one day, I just happened to spot the remains of The Verdict and Knightrous Wedge sitting on a shelf together and thought, “Hmm, those could almost bolt together…”

And so, we began making a chimera from these two corpses.

Gas bottle vert spinner with a floor shaving wedge…

Let the gutting begin.

Everything removed from The Verdict.

Lol, budget Cobalt…

Time to start cutting up Knightrous Wedge.

First few bits

More and more

Now to cut away more and more to make them join together

Due to weight the plow disc gets cut back to the bar minimum

Close and closer

Now it needs some short term bonds

With it tacked together, I will be able to grind away all the exist wedge and gas bottle till everything matches up nicely.

Till next time…

RoboWars Returns – 14/01/2023 – Day 1

Posted on by Half Done Things

RoboWars Returns – 14/01/2023 – Day 1

In December RoboWars announced a Sportsmen event to be held in Hamilton, Queensland. Below is a collection of photos and diary of the event from my fuzzy memory.

 

Fight 1: PotHead

Other than driving The Verdict for 30 seconds prior to leaving for the event a day before, I was going into this one blind. And it really showed. I’m super rusty with my driving, doing a lot of weaving instead of straight driving, spinning in circles from over shooting when turning (Really should have put some steering rates into the radio) and I noticed one side was a little bound up compared to the other (it pulled to one side when going forward).

There was a lot of dancing around as I tried to pin Pothead to the wall so I could wail on it with the hammer, but it was actually hard to push to the wall without it slipping off the front. Eventually I managed to get a few decent hits, mangling the pot easily.

Pothead’s saw was scratching the paint in the corners when we collided but did nothing more then that which was nice. However by the timer ran out, the judges has decided the winner was Pothead. It went the full three minutes and didn’t fail, so I consider that a good start to the event. Back in the pits, I just tightened all the nuts and bolts to ensure nothing was going to fall apart and then charged the battery, ready for the next match

Result: Loss by Judges Decision.
Watch the fight here: https://www.youtube.com/watch?v=Rsgc7zcOLUM


Fight 2: Raptor
After the Pothead match, I dug into the menus of the radio and dialed in some rate limiting on the steering to try to reduce the twitchiness. Raptor is a full fat featherweight that swapped out their usually vertical discs for a pair of saw blades and wedges…… (I wasn’t expecting these since it was a sportsmen event, but the EO allowed it.)

There was a lot of back and forth, sparks and hammering through out the match, there was a moment where they actually wedged me up and onto the weapon, which missed the internals my a few millimeters. After that, as it was clear the wedgelets were not something I could defeat, I just focused on pushing against their weapon, trying to hammer, stall and push them where possible. For the last ~30 seconds, I just jammed the weapon down on them to clamped on (The APD speed controller did well here, the thermal/current limiting saving it.)

Sadly, the judges gave it to Raptor.
Once again, there was no real damage other then a slice into the tongue on the robot and some more scratched paint.

Result: Loss by Judges Decision.
Watch the video here: https://www.youtube.com/watch?v=cl5Bw53AW8Q

Unfortunately we are now out of the competition, so we can only compete in exhibition matches and melees.

Knightrous Wedge: The Vertical Slice – Part 9

Posted on by Half Done Things

It’s been a bit quiet here as we’ve been busy!

Quickly CNC’d up some motor mounts and supports for the drive

Started machining the weapon hub

Then drilling it out

Then boring it

Then making some bushes

Bushes pressed into the weapon hub, then the assembly pressed into the weapon bar.

A quick dummy fit.

Picked up the weapon belts. HTD 5M-325-15

Machining the weapon timing pulley. A 36T pulley to give the weapon a 2.4:1 reduction.

A quick dummy fit again.

The weapon motor mount… an after thought…

After cutting the upright and tack welding it in.

Motor mounted

Belt fitted.

3D printed jigs are awesome.

Drive mostly ready.

Knightrous Wedge: The Vertical Slice – Part 8

Posted on by Half Done Things

Another update!


Batteries arrived, this will give Knightrous a 12S 2.2Ah capacity.


This decision was something I had been holding off, on doing for a while, but it became inevitable with the requirements for this robot. The drive and wheels must go close to the weapon axis and it needs more space to fit them. So the original chassis and wheel guards had to be removed….


This left it looking very bare, but it did make space!


I’m still undecided on which drive configuration I’m going to decide on.


The spur gears are a very simple setup, uses off the shelf parts and will be easy to repair and service


The planetary gearboxes are more expensive, require some modifications but have a nice and simple form factor that suits the robot.


The new wheel guards tack welded in. More bracing and reinforcement to come!