Unnamed FW crusher build diary

This is so nice! lol

Does your hdpe just screw together? Interested as looking to have a go with hdpe :)

Thanks David, The HDPE doesn't just screw together. The more structural elements such as the base plate are attached to the chassis using bolts that go into threaded box section aluminium bar. The armour panels screw into frame underneath them to give them a bit more strength and support. The only place one panel screws into another is on the top of the oil tank where the armour piece is nice and thick to try and stop axes and is therefore suitable (I hope) for attaching straight into. I had never used HDPE before now, but so far have found it really easy to work with using just basic tools.

I have an image of the left handed bolts i can produce on another page: http://www.fightingrobots.co.uk/thre...883#post467883

To answer the safety questions, I think any kind of sturdy flat object to rest your robot on is fine, as long as it keeps the wheels out of contact with anything. The locking bar should just stop the weapon from moving I believe, though it has to be insertable without touching the weapon. I think Razer had a bar that went through its weapon and then down to the wedge, but maybe I'm thinking of another robot.

Thanks Rory, I can make a piece that jams the jaw open without having to touch the weapon itself, but I'll check with the event organisers before committing to it unless anyone else can chime with something different.

Al_ one idea could be to drill a hole at the base of the jaw, and slide a bar through the lattice through the hole and into the other side.

Drilling a hole through the arms and threading a bar through the chassis was going to be my backup option, but if I don't need to, then I'd rather not start drilling holes and risk weakening it. If I do have to drill it, an I correct in thinking that drilling through the center line of the arms is the place where it would weaken it the least?

In a mini update, the diet started today and I have saved a good chunk of weight off it, Just a couple of hundred more grams to go :oops:

Its been a fair while since the last update, but I thought I ought to tie the loose ends of this build diary together.

First up, through selective removal of material not deemed necessary for function (a.k.a. cutting holes) I'm happy I have the bot down to the required weight now. I have had it on 2 different sets of parcel scales, one puts it at 13.35kg and the other at 13.50kg, so while its close, I should be under the limit. I have also prepared a couple of lighter armour panels I can swap out should the official scales say that its a bit over the limit, but I hope it wont come to that.

Next up, I have taken care of the required safety features for the live event in the form of sharp edge protection and a lock for the jaw. I have also made a cradle out of some spare 2x4's that I had available.

I have got the steel cables for the self righting arms connected up and got them to actuate just over the last couple of centimetres of movement of the ram. This means that in normal operation they don't move, but if I need to self right I can shove the jaw fully open and actuate the arms.

Other than that I have just tidied up a few details like grinding the front wedge down to get it close to the floor, putting more of a point on the crusher tip and making sure everything is tight.

Its off to the Grantham event this weekend, no idea how it will go, but it should be fun finding out. To be fair if it doesn't come back in bits and it is still somewhat functional, I'll call that good. Likewise I'm fully expecting a lot of bugs and a whole list of things to work on or improve for the future. If things go to plan, I might get a chance to have a bit more testing / driving practice tomorrow morning which I definitely need.

No pics this time unfortunately, its been too mush of a rush to get finished in time. However I hope to take lots at the event and I'll post them up here afterwards.

It is the day after a great weekend at Robots Live in Grantham, so here is a quick write up on my, and the robot’s first event.

I had 3 melees over the weekend, the first of which was the second fight of the first day with about 8 other feathers in the arena. It was exactly as chaotic as you would expect and I can’t remember a lot of the details from the fight. Overall I was happy with how the robot drove and I was finding it reasonably controllable despite many driving mistake from me, such as lifting the jaw up when I had someone on the wedge instead of bringing it down – doh! A few of the flippers were having fun turning me over and over. When it landed on its back, it flipped back forwards on to its wedge as designed, so I was happy with that. However when I was flipped on its side and I went to self-right, the axle that the self-righter pivots around popped out of its housing. From then on I was dragging the righting arm around with me and occasionally getting hung up on it. Still it lasted the full 3 minutes and with the exception of the self-righting arm, it was still working at the end so I was well chuffed for a first time out.

Back in the pits I put the self-righter axle back in its housing and secured it in place with screws to stop it popping out again, then I charged the batteries and it was on to melee 2……

There were a few more feathers in this time, probably 11 or so, so even more chaotic than last time. This fight was 3rd on the second day and one thing I hadn’t thought of was the condition of the arena floor with all the chunks the heavies take out of it and the debris from those chunks. My side armour is low to the ground to try and stop flippers getting underneath. Unfortunately the flippers were still getting under it but I was also getting high cantered on the debris or hung up in a divot. Therefore the driving/handling this time was awful and after only half a minute or so explosion saw me struggling near the side and swiftly threw me clean OOTA.
In the pits again I decided to cut off some of the overhang on the side armour to increase ground clearance. I was getting flipped anyway, but I figured at least this way I could drive around better. Then charge the batteries, no damage to fix and off for melee 3….

With the higher ground clearance driving was definitely improved over the second fight and I could at least mix it up a bit. The fight was going pretty well until around half way through when I was flipped onto my side and it again failed to self-right. I knew the axle had stayed in this time but I didn’t know what was wrong. I was stuck on my side any only able to spin around in circles, and the fight went downhill from there. I was flipped across the arena to the house robot who kindly hit me few times with its sledge hammer. Then it put me under the red arena hammer controlled by someone from the audience who gave it some more hits. Still on my side I was able to spin away but the house robot grabbed my again, then did the spin around the in the middle of the arena, release and throw a robot to the side routine. Annoyingly it threw me right into the recess where it sits so it came over, grabbed me again, gave me a few hits from its hammer and put me on the arena floor flipper. The floor flipper had already thrown one feather up to the roof net, and I think it was Hatchet that it threw clean OOTA from the other side of it. I didn’t quite end up OOTA but had a direct hit into the arena wall. Then just for good measure and to collect the full set of hazards I finished the fight with a few smacks from under the blue arena hammer.

Back in the pits and I was amazed to find the drive and weapon were still working despite the damage to the other parts of the robot. A few pictures below show the damage. One wheel took a lot of the hammer hits, its cracked but still in one piece. Likewise I think it was the house robot that was hitting the armour over the oil tank which was bent out of shape, but the tank underneath was fine. The failure of the self-righting this time was down to the cable that pulls the arm snapping. I don’t know why it snapped, it should have the strength to turn the bot back over, but when I went to use it there were other robots around so maybe I was hung up on another robot as well. Either way I’m going to have to replace it with something stronger.

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I have a number of ideas for tweaks and improvements that I’ll detail with some more posts in this thread when I get round to them. However I have to say the biggest one is probably lots more practice driving the robot. It’s amazing just how good some of the other roboteers are at driving their machines.

Finally I have to say that it was great to meet everyone who I spoke to and a big thanks to those that helped me out and answered all my questions. I had a fantastic time, the whole event was great fun and I’m already looking forward to the next one.

Well, that's it well bedded-in anyway! Glad it came back in one piece at least, did you get to crush anyone to a great degree?

While I had a few good opportunities to do so, I didn't manage to thanks to being a crap/nervous/inexperienced driver :oops:

I’m updating this thread to detail a few upgrades on Pressure Point ready for next year. Overall I have been pretty happy with how it has gone at a couple of events, however there are a few areas that need some attention that I’ll go into below. None the less, I think its gone ok for a first attempt at a feather.


The first thing I had to address was to find some things to save a bit of weight on the bot to put into the areas that need attention. The most obvious of these was the crusher arms. Unlike the chassis which has weight saving triangles cut out of it, the arms are solid aluminium pieces. I have re-designed the arms to have the same weight saving cut outs in them and the water jetters turned them around pretty quickly for me. Old arms and new lighter ones are shown below, total weight saving a shade over 200g.

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Next up for attention was the armour panels for the sides and top. Each side and top piece of armour is currently made from 2 panels of HDPE bracketed together to get the required bend in them as the bot tapers from back to front. I decided to replace these with a single panel that is bent to achieve this same thing. This means a better panel fit, weight saved be not having all the bracketry and hopefully a stronger panel too. After watching a few videos, I found the HDPE is easy to bend with just a heat gun. I set a couple of pieces of metal up in a vice with small gap between them, and placed the HDPE behind them so I would only be heating up the strip where I wanted the bend to be. After a couple of minutes the HDPE was soft enough that it could be offered up to the bot and bent into shape. Old armour and new are shown below with about another 200g saved. I also replaced the baseplate and rear armour with identical pieces as these were showing the most wear of the remaining pieces.

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With some weight saved it was time to start fixing some problems and first up are the wheels. Since the wheels are exposed they take a fair beating, particularly from arena hammers or from flippers when landing wheel first. The current wheels are nylon with bike tyres screwed to the outside of them and while they have proven to be fairly strong, they are way to brittle and all my wheels had cracked and one had failed completely.

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I should say thanks to Shakey for the suggestion to make some out of HDPE. It had held up fine on the rest of the bot so I hope it should be fine as wheels, plus it doesn’t seem to have the brittleness of Nylon. This is what I have come up with. It’s the same weight as the Nylon wheel with the same tire on it, but made from 20mm HDPE. Totally untested in battle as of yet, but fingers crossed it will work.

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The biggest issue I have had by far has been the self righters. The first incarnation was too weak, with the arms flexing and when that was refined this then caused the cables that pull the arms to work lose. With the weight saved from the armour and crushing arms, I have designed some stronger self righters shown below. The original V1 is on the left, the intermediate V1.1 is in the middle and the new V2 in on the right.
V2 is beefed up in all directions and 20mm thick and wide instead of 10mm which should remove most of the flexing. It also has a small metal bushing pressed into the bottom hole where the steel cable passes through it to protect it from the cable cutting into it.

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The issue with the steel cable fixing was that it was held under the bolt and washer that secure the end of the ram to the crusher arm. The idea been as the arm moves in and out it pulls on the cable to move the self righting arms. However when the bot needed to self right and the cable was pulling against the bot’s weight it was sliding out from under the washer no matter how hard I tightened the bolt. To address this I have fitted 2 more fixings that go through the washer and into the arm below. This will pinch the cable on both sides and in a total 3 places. Plus I will also add a crimp on the cable as it exits the washer to further prevent it pulling through. You can see blow the black line on the washer which shows where the cable goes below it and the extra fixings for holding it.

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The cables are not fitted or tested yet as they needs an extra pair of hands to fit. There is also going to be a slightly wider front wedge to swap over when it arrives which should aid getting under other robots but otherwise Pressure Point’s upgrades are complete for now. As you can see, they leave the robot looking almost the same as it did before. See you in the arena!

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microwaves be afraid, be VERY afraid XD

Nawww i looks great now if i could get of my ass and finsh my bot it would be good.

I love the look of those wheels. HDPE should be fine for that, Gabriel 2 can attest to that I am sure. ;) Looking forwards to meeting Pressure Point back in the arena.