Team Shakey Build Diary

[Shakey]

Shakey: Your robots are immensely well printed so I would just love to get results like that! I was wondering which filament you used for yours. By the way, your problem with Carbon is probably due to either weight distribution or friction. At the last event, you may have noticed AntWithTopHat running a lot more freely. This is because I added a little springy piece of acetate substitute (yes, another piece of laminate) underneath the front of the robot which actually raised the body of the robot off of the ground and made it drive so much better; give it a try with some acetate and see if it works for Carbon! I would love to see it driving nicely.

Anybody else who could recommend filament would be very much appreciated. I was thinking of using the green 1KG roll of 1.75mm PLA at this link (if the colour really is that bright!) : http://www.ebay.co.uk/itm/3D-Printer-fi ... 4d2465952e . Would that work well or would it just be completely useless?

Thankyou! On the filament front I just use this, http://www.ebay.co.uk/itm/New-3D-Printe ... 51ba2baf93 quality is good enough though the diameter varies a tad (Digital calipers are a lifesaver!). Though it looks like the same stuff in your link, I just buy from here as I normally need faster shipping. Though I haven't really tried many PLA sources so am by no means an expert. On the thought of getting your own printer just be aware that they are far from plug and play, moreso the hobbyist kind like the i3 is and other RepRap/Printrbot etc. Plus not being the cheapest of things just make sure you research your choice as best as you can and get to know exactly what you'll get for your money!

On Carbon it is already held on the acetate at the front and is a fairly well balanced robot, at one point we got it driving right but deteriorated quite quickly, but even when it was driving 'right' it still was no where near as controllable as some of my other bots. I have some silicone on the way to do my own tyres (It worked out cheaper than buying the amount of pololu tyres I need to replace the worlds supply my team managed to get destroyed at Basingstoke!) and I'll see what effect they have.

And finally: Oh dammit, my robots already seem to have trouble coping with yours it's only going to get trickier!

[peterwaller]

Which silicone are you going to use for the tyres and what shore hardness is it.
As you know most of mine (whiteish) are the dragonskin material which is A10 hardness which equates to about 00-55 on the softer scale.
I have been recently been experimenting with Ecoflex both 00-30 and 00-10 which are softer but have more stretch.
I think the 00-10 is best for the nano's but probably the 00-30 is better for ants but thats just an impression and I would be interested to hear what you find when you get started.
Although these materials give much better grip I have found that the improvement in controllability of spinners due to their ability to absorb vibration is equally important and virtually illiminate the skating about often experienced.

[Hogi]

are you going to make a spinner antroboteer?

[Shakey]

Which silicone are you going to use for the tyres and what shore hardness is it.
As you know most of mine (whiteish) are the dragonskin material which is A10 hardness which equates to about 00-55 on the softer scale.
I have been recently been experimenting with Ecoflex both 00-30 and 00-10 which are softer but have more stretch.
I think the 00-10 is best for the nano's but probably the 00-30 is better for ants but thats just an impression and I would be interested to hear what you find when you get started.
Although these materials give much better grip I have found that the improvement in controllability of spinners due to their ability to absorb vibration is equally important and virtually illiminate the skating about often experienced.

It was after our talks about the improvement to your spinners control I decided to go down this route, Hexa-Chopper has some serious issues with control when spinning the disc at any reasonable speed as the tyres are quite hard not damping any vibration. It's some Shore A10 stuff though not the dragon skin, it's a cheaper alternative. I was choosing between that and some Shore A27 stuff but decided the slight extra softness would help as I don't have much room for more tyre in the robot so if I can get the same benefit from something thinner that'll help. Interesting about the even softer tyres, I'll have to see what improvement the A10 brings to my robots. I did also pick up silicone black pigment aswell, I quite like having the dark tyres on white/red robots.

Do you use any release agents when you mould?

[AntRoboteer]

Shakey: Thank you very much for your reply! I will definitely buy that filiment if I am able to get one of these beasts!

Hogi: Maybe! I have my eye on some 60,000 rpm (yes, 60,000!) DC motors which might be good for a spinner (a very small one that is as they are tiny coreless motors) so I shall give that a try as well as trying to make an autonomous cluster partner for one of my robots. Does anybody know if that's allowed? If they did, I would be very grateful!

[Shakey]

I'd wonder if the 60,000 RPM motors are actually up to the job. Speedwise it sounds great but torque wise they may be very weak and wouldn't be able to spin up quick enough to be up to speed when the two robots first hit, they might not even achieve full speed due to lower torque. in addition the faster the blade spins the less bite it gets when it hits an opponent, bite being how far into your blade they are when the tooth hits. Bite really decides how much of the energy is transferred, a tiny bite will probably just make a small gouge damaging the armour while a large bite will dig in transferring more energy but in a throwing kind of way. It's whether you decide you want a cutting or a throwing style of spinner. It's one of the reasons HSOD has trouble with Antivation cluster, it can't bite those robots well enough, it just rips the armour rather than digging in and throwing/removing the whole panel. For reference in HSOD vs. Antivation cluster the blade is normally doing about 10000-12500 RPM. In HSOD vs. Salt n Pepper from the last AWS (http://youtu.be/ra9JjY45TKI?t=2h37m25s Also one thing I'd like to say rewatching that is please refrain from calling stop on a battle you're not in. It doesn't count and confuses roboteers. If the LiPo is exposed it is the roboteers decision if they want to risk fighting on. ) most these hits are done about 15000-17500 RPM with a 12g disc. The motor in HSOD can get 30,000 RPM on 2 cell but I lose control of the robot about 20,000 RPM and there is a huge risk of flinging itself out the arena.

I'm not saying don't try the 60,000 ROM motors if you want, I just think you'll find it slow to spin up and a lot of your top range throttle unusable for being too fast and causing too much vibration.

A standard speed (1500 - 2000 kv ) brushless motor in the 12-25g weight range (About £12 for motor and ESC normally) might be a good start just to give you an understanding of how spinners behave before you try insanely fast discs!

[AntRoboteer]

Very wise words there! I had no idea that these spinners actually spun up that fast but probably because the heavyweights in Robot Wars had discs at around 700rpm! I am now wondering about propeller power with one of those motors which could be quite ineffective but fun anyway! A different type of fan robot would add some variety I think and I thought I could do it as a nano as such a small amount of weight should fly very well!

Also, I agree that people should refrain from shouting stop during other battles like with Yoink where the battery repeatedly falls out, people either gasp, shout stop or other crazy reactions which could interfere with the driver's concentration. As Pete showed at the Open with Anticyclone's battery hanging out, if you are a good driver, you can avoid a huge fire and win the fight at the same time!

[Hogi]

to answer your question on autonomous robots. i think it'd be allowed in provided it could be remotely shut down.

[peterwaller]

Do you use any release agents when you mould?

No the biggest problem is getting the rubber to stick to anything.
Even with special glue I have found I needed rimmed wheels to keep them on but if you are putting them on the pololu wheels the center rim will probably do.

As Pete showed at the Open with Anticyclone's battery hanging out, if you are a good driver, you can avoid a huge fire and win the fight at the same time!

I have never been accused of being a good driver before.

[Shakey]

First test of the silicone tyres underway! This type of silicone takes about 10 hours before it can be demoulded but ideally should be left for a full day. I wasn't sure on the amount of silicone and ended up only filling 3 of 4 moulds. I'll see what difference they make to carbon once they are done.

The mould and wheel:



Silicone poured in:


If these are any decent would people be interested in buying some? If so I can get some coppers back in the antweight fund for ESC experimenting!