T_Y's Build Log

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T_Y
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Location: York

Re: T_Y's Build Log

Post by T_Y »

It's been a while since the last update. I wish I could say I've made loads of progress but not really.

Aside from finishing this design...

Image

Image

Introducing my gripper, tentatively named Problem Exists Between Chock and Chops i.e. PEBCAC (totally didn't search up synonyms for wedge and mouth/jaw!).

The jaw is designed around a 120RPM 12V N20 motor with a threaded shaft (M4, 55mm). The 'teeth' won't be designed to pierce armour, just grip onto the top of the opponent. To be honest, it probably won't be that effective (slow motors, but hopefully good torque for grip), but it's something I haven't seen be done so I wanted to try it out! The chassis is based on HYTTIOAOA, but modified to account for the jaw mechanism. I'm going to need to go through a few iterations to get the system properly working.

The intention is to get PEBCAC ready for AWS58. I also need to repair INABIAF (planning on putting a much better servo in it), and HYTTIOAOA is basically ready, it just needs tire replacements.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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LimaHotel
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Re: T_Y's Build Log

Post by LimaHotel »

Looking good! I'm not sure those Jaws open wide enough though - Kyro struggled to grab Jiggy with Mantis this weekend
A grabber? I CHALLENGE IT WITH JIGGY!
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Kyro
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Re: T_Y's Build Log

Post by Kyro »

yeah... im currently modifying mantis to have a bigger grab... not sure whether it will be an attachment, or whether it will be a permanent modification yet...

either way, mantis shall have its revenge...
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T_Y
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Location: York

Re: T_Y's Build Log

Post by T_Y »

A bigger grab would be nice, something to look ahead to once I get the concept running. A gripper rumble would be cool!

I've spent this week ordering gubbins off ebay and other sites to build/repair my bots. One of the things I picked up was a screw tap, so hopefully that should help my screw holes in the 3D prints from losing grip on the screws too easily.

I've been printing off a wireframe version of the gripper before I start cutting the polycarb armour, to first test the design will fit in the box and secondly to act as guides for my cutting - I've been a little inaccurate on some cuts/drills with my previous bots, and for something like this I wanted to make sure I got the cuts right to ensure good action on the mechanism.

The good news it that it does look like it'll fit inside the 4 inch cube (my cube is a bodged card cube so flexes). I though I'd need to cut the shaft down to get it to fit but I'm fairly confident that it should fit inside the box once fully built- I just need to start each fight with the jaw closed.

I've also renamed the bot to Working As Intended.

(For some reason, copying the BBCode link from Imgur isn't working on the images right now)
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Re: T_Y's Build Log

Post by T_Y »

Update time!

The polycarb for WIA has been cut out and drilled (and re-drilled when I messed up the hole positions). I've screwed the thing together and it looks good, pretty low ground clearance at the front and almost level. The ground clearance should be sorted when I add the forks.

https://imgur.com/etkgfXg

Here is a pic of the gripper mechanism - the threaded block at the back is on a pivot, as well as the motor and the jaw, so it should be able to move around with no issue.

https://imgur.com/aEpf50Z

One thing that I know I need to change already is to add some kind of srimech, at the moment it will get stranded on its back. If I have weight, I'm planning on putting a light servo on it.

Next step is to wire it all up and test it.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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LimaHotel
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Re: T_Y's Build Log

Post by LimaHotel »

It's been over a year man, I'm really looking forwards to catching up!
On the subject of robots though - what's your lineup looking like? Hyttioaoa, inabiaf, and WAI?
A grabber? I CHALLENGE IT WITH JIGGY!
T_Y
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Re: T_Y's Build Log

Post by T_Y »

Aye, it'll be good to catch up. Maybe we'll draw each other in a fight - Jiggy vs WAI? :)

My lineup is going to be HYTTIOAOA, WAI and INABIAF. There's still a few weeks to go, so I might be able to put some fast servos into INABIAF and HYTTIOAOA (I ordered those KingMax servos you tested out).
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Re: T_Y's Build Log

Post by LimaHotel »

I'm good for a whiteboard if you are :P
And nice! I'm thinking of buying one to put in Jammin' Good. The pink gives a good flip but it's nothing next to what the KingMax is doing in my brother's bot!
A grabber? I CHALLENGE IT WITH JIGGY!
T_Y
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Location: York

Re: T_Y's Build Log

Post by T_Y »

I've had a productive Saturday!

First thing is I've bought some wood to build a small test arena for non-spinner designs. It's going to be around 60cm square with 15cm square pits in the corners.

The main thing I've done is finished the wiring for Working as Intended! I still need to add forks to the wedge and armour up the exposed wires.

Image

Image

Here it is in action:

https://youtu.be/4tYPHP8v6pQ

As you can see, the jaw can grip, but things can slip out fairly easily. I need a better gripping system - maybe drive some screws through the jaw to act as the teeth instead of a bit of rubber. It's also very slow - version 2 definitely needs a faster worm gear N20. The drive is supposed to be 300RPM but seems a lot slower than HYTTIOAOA. In any case, I want to upgrade the drive on all my bots to 500RPM...

If you're interested in how the weapon works, I've got a quick explanation video here:

https://youtu.be/BjCmo6a6GGA

Just need to finish off the last bits on WAI, then I need to re-wire INABIAF. In the meantime, my 3D printer is going to start pumping out spare parts!
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Kyro
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Re: T_Y's Build Log

Post by Kyro »

yes these seem a bit slower than 300 rpm...

i use 600rpm n20's for my bots (1200rpm at 12v) and i have more than enough speed with plenty of torque... i personally wouldnt go much higher than this as i don't think its needed...

i use silicone for the grips on the end of mantis's grabber... the little mg90 1.8kg/cm i use for the grab can hold shut an mg92b with 3.5kg of torque... although im upgrading it to another mg92b before aws as I have the weight spare and why not go all out??

silicone seems to work well... although my grabber has 3 prongs for grip... i dont know if it would be as effective on your jaw design as it is for me... maybe experiment with screws inside silicone so the silicone would squash and allow the screws to bite... im thinking it would be like a double whammie for gripping... one is likely to grip your opponent
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Trappist 1(4wd grab 'n' lift)
Ton 618 (4wd expanding bot)
Io(4wd flipper)
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