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Custom 2-3-2
Rats... I was going to offer to make your arm but the shipping would be expensive. I’m good with metal but the coding for the shadow system integration is tough for me!

I’m in the US on the east coast.

Troy
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(05-21-2019, 04:01 AM)cobra troy Wrote: Rats... I was going to offer to make your arm but the shipping would be expensive. I’m good with metal but the coding for the shadow system integration is tough for me!

I’m in the US on the east coast.

Troy

Hi Troy,

For the arm, I suppose that I need to begin with a 12mm x 12mm x 3mm aluminium corner, cut off some parts, where appropriate, bend it (using a blow torch and a guide), and drill the holes. Is there a better way to do this?

Regarding the SHADOW system, I haven't worked on it before and it's a good 6,000+ lines of code but I'm happy to dive into it and make the necessary changes.

What functionality do you need to modify/add? Is it mapping a controller button (or combination of) to the function that triggers the 2-3/3-2 transition? How does Martyman's droid currently work? I'd like to better understand what's the current "state of the art", so that I don't replicate work already completed by  others.

I've just ordered an USB Shield and a couple more components for SHADOW, I think I already have two PS3 Move controllers in my closet, so I can start experimenting fairly soon.

Nikos
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Hi Nikos

You don't need heat to bend the aluminium, or even steel. Just clamp it and use some force. But otherwise, sounds like you are on the right track.

The electronic control of the 2-3-2 system seems to be largely a roll your own situation across the R2 builders at the moment. The 2-3-2 systems are all a bit different and need different methods of control. I think Troy and I are both at the point where we are still triggering our 2-3-2 transitions by touching wires on batteries.

As I mentioned in another thread I have decided to start again with my whole control system. I am going to try and re-implement SHADOW-MD on a more powerful board (M4 Metro Grand Central) and then extend it to both directly control my 2-3-2 and my ODrive based foot drives. The more powerful board is really just insurance against trying to add too much functionality and running out of pins or clock cycles to get it all done. It might even have the power to play back the sounds directly, but that may be pushing its capabilities.

The previous track I was going down was to write arduino code to emulate Sabertooth motor controllers, to then drive the ODrive controllers. I was also emulating an extra Sabertooth that would control the 2-3-2 system. The control triggers for this would then have to be hacked back into the SHADOW-MD code. I got some way through the code that receives the Sabertooth commands, but did not look into the required modifications to SHADOW-MD.

Martin
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Hi Martin,

Ok, let us know if you need help with something. You're well ahead and it will take me some time to catch up but I'm happy to help, if/when needed.

I've just started the process of priming/sanding/.../painting of the body, legs and dome. I'm trying to get this done within 2-3 weeks, if possible, before I put together the 2-3-2 mechanism, for which I've ordered the required parts.
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I was demonstrating my 2-3-2 mechanism this weekend and the primary lift arm split at the point where it fits to the motor shaft. Luckily R2 was in two leg mode at the time or he would have face planted.

I suspect that if you used something stronger than PLA the current lift arm design might be OK, but I will be redesigning it. I think the safest way to go would be to include a hand filed aluminium plate as a reinforcement. Alternatively you could probably create the primary lift arm entirely out of metal, but that is probably overkill.
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(06-23-2019, 11:01 AM)Martyman Wrote: I was demonstrating my 2-3-2 mechanism this weekend and the primary lift arm split at the point where it fits to the motor shaft. Luckily R2 was in two leg mode at the time or he would have face planted.

I suspect that if you used something stronger than PLA the current lift arm design might be OK, but I will be redesigning it. I think the safest way to go would be to include a hand filed aluminium plate as a reinforcement. Alternatively you could probably create the primary lift arm entirely out of metal, but that is probably overkill.

Thanks for sharing. I'll try to hand-file an aluminium as reinforcement.

Any progress with the electronics/software?
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I decided I would try a beefed up 3D printed design and print it in PETG.

[Image: attachment.php?aid=1572]

I can't imagine this piece breaking, especially once I have my endstops wired up and stop driving the lift motor hard against the end of travel.

The STL for this part is in the beta parts folder of my google drive share. I haven't testing it yet for clearance against the motor.

My control system is coming along slowly. Probably still a while off, as I haven't had much time to work on it lately.

Martin


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That looks pretty strong, which PETG filament are you using?
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Hi Martin,

I've just finished with sanding and painting R2-D2's body and legs, which means I can now focus on the 2-3-2 mech.

On step 15, there's a tricky bit. The nuts in the hub to screw in the inner hub fall off from the other side and I needed to remove the outer hub to put them back in. It's necessary to either glue them in or 3D-print plastic inserts (shape of a think nuts), to hold the nut in place. I used glue, as my printer was busy, working on the outer shells of the feet.

A couple of questions, in case you can help:

I can't find the new bracket in the beta folder; has it now replaced the standard one?

Also, I've been wondering if it would be possible to use a hard flexible filament (TPU) for the hubs, to absorb/dumpen vibrations coming from the legs and from the hub motors. In this case, besides the hubs, which other parts would you consider appropriate to print with TPU?

Thanks and regards,
Nikos
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