You should test the weapon directly attached to the motor as a baseline for power usage, then you can calculate how much power you are losing to the drivetrain and bearings.
True. But I'm not sure what it would really tell me, I NEED the setup the way it is, so it might tell me what losses I have, but I really wouldn't be in a position to change/correct it, because I need at least what I've already designed. I am going to try and test the overall efficiency of the ESC (measure power going in and out of the ESC), this is where losses can occur, and I can recover without sacrificing any of the mechanical design.
I tried this, and it was maybe 0.5A total current draw difference, and only at top speed. I had this thought too, and it doesn't really change much. But don't worry, I have some ideas and in future videos I'll show how I reduced it pretty drastically.
Have you tried running the belt inside out? Since you're not using the teeth anyway. Alternatively print teeth on your pulleys and reduce the wrap angle on the drive to allow skipping in case of a hit. Direct drive with no slip, except under major impact. Relying on belt tension with such a non-stretchy belt feels risky.
Not yet. I'm still not 'done' with the pulleys, I always work with 'proof of concept' first, then finalize the parts and make them the best they can be.
You could make the pullies aluminum and just add spokes to hollow it the middle of pullies. Similar to motorcycle sprockets. It makes them super expensive to make timewise since you can't just hit print but it may be worth drawing something up to get a weight estimate.
Saw you on BBots! Think about making your weapon cross section into a symmetrical airfoil shape, and cover those lightening holes with tape etc. This is your best shot at increasing max weapon rpm and reducing amp draw while there.
1) I don't want to increase RPM, this is already way too fast. 2) I tried taping over the holes and it made almost no difference 3) actually tweaking the firmware on the ESC is a great way to reduce the current draw, I've reduced it by around 30%. 4) I'd rather not machine this weapon more than I have to, especially with complex shapes.
Thanks for the reply! I understand if you've gotten current draw down low enough to suit the 3 minute operational design, that over engineering shapes would be a lot of work for very little purpose at this point. I come from an aeronautical background, where every electron is precious so efficiencies (electrical, mechanical, and aerodynamic) have to be refined endlessly. Loved watching Copperhead on BBots; wish you the best of luck from here on out!
Are the pullies going to suffer when the weapon stops rotating during combat and the belt presumably slips? Are you worried about heat generated in that instance?
I don't think so. The acceleration forces are pretty strong, and the surface finish looks flawless still and I've gone through maybe 5 batteries. I think they could hold up, the belt might slip a bit, but that's perfectly fine and desirable.
I'm not sure if it was turned on (it shouldn't have been), but keep in mind the top speed is 10K RPM, with the amount of wind resistance, just backing off the throttle will create some sort of braking effect.
Possibly, but it COULD be at the expense of hitting force. Don't worry, I will show you how I cut down the current draw to significantly less. I have it down to 23A, and I should be able to get it even lower with a quicker spin-up time.
Slightly off topic: All your recent videos look really washed out and green tinted. Did you by any chance switch to a different camera and forget to adjust the color grading in your editing program?
Yeah, I'm trying different grading. I just need to sit down and create a final profile, I'm not all that thrilled with this one, I just need to work on it more, but I'm spending too much time actually making stuff and haven't spent the time to change the grading.
You should test the weapon directly attached to the motor as a baseline for power usage, then you can calculate how much power you are losing to the drivetrain and bearings.
True. But I'm not sure what it would really tell me, I NEED the setup the way it is, so it might tell me what losses I have, but I really wouldn't be in a position to change/correct it, because I need at least what I've already designed. I am going to try and test the overall efficiency of the ESC (measure power going in and out of the ESC), this is where losses can occur, and I can recover without sacrificing any of the mechanical design.
Sounds like the holes in the weapon is causing a lot of air resistance. Can you try putting tape over the holes to see if its any better?.
I tried this, and it was maybe 0.5A total current draw difference, and only at top speed. I had this thought too, and it doesn't really change much. But don't worry, I have some ideas and in future videos I'll show how I reduced it pretty drastically.
Have you tried running the belt inside out? Since you're not using the teeth anyway.
Alternatively print teeth on your pulleys and reduce the wrap angle on the drive to allow skipping in case of a hit. Direct drive with no slip, except under major impact. Relying on belt tension with such a non-stretchy belt feels risky.
Not yet. I'm still not 'done' with the pulleys, I always work with 'proof of concept' first, then finalize the parts and make them the best they can be.
It would be a pipe dream to see this go up against Team Velocity's beetleweight bar Debacle.
I watched all of the fights I could find with Debacle when researching this design. It would be interesting to see the two fight.
You could make the pullies aluminum and just add spokes to hollow it the middle of pullies. Similar to motorcycle sprockets. It makes them super expensive to make timewise since you can't just hit print but it may be worth drawing something up to get a weight estimate.
Yep, I have designs for this, but I would rather stick with plastic if I can, since it's MUCH easier to make and reduces part count.
You can also change your esc for a exuav 70a, they are cheap, lightweight and as far as i heard, very precise.
Stay tuned, I'm testing many other ESCs and have found some that work. This is JUST the pulley video, electronics will be covered in future videos.
Saw you on BBots! Think about making your weapon cross section into a symmetrical airfoil shape, and cover those lightening holes with tape etc. This is your best shot at increasing max weapon rpm and reducing amp draw while there.
1) I don't want to increase RPM, this is already way too fast. 2) I tried taping over the holes and it made almost no difference 3) actually tweaking the firmware on the ESC is a great way to reduce the current draw, I've reduced it by around 30%. 4) I'd rather not machine this weapon more than I have to, especially with complex shapes.
Thanks for the reply! I understand if you've gotten current draw down low enough to suit the 3 minute operational design, that over engineering shapes would be a lot of work for very little purpose at this point. I come from an aeronautical background, where every electron is precious so efficiencies (electrical, mechanical, and aerodynamic) have to be refined endlessly. Loved watching Copperhead on BBots; wish you the best of luck from here on out!
Are the pullies going to suffer when the weapon stops rotating during combat and the belt presumably slips? Are you worried about heat generated in that instance?
I don't think so. The acceleration forces are pretty strong, and the surface finish looks flawless still and I've gone through maybe 5 batteries. I think they could hold up, the belt might slip a bit, but that's perfectly fine and desirable.
I really wanted you to throw something into the wooden weapon when it was spun up... Maybe some lettuce or a banana for scale. Haha
Coming soon :-)
9:25 was your weapon ESC' brake turned on? I noticed that the weapon stopped quite quickly from full speed and braking can cause a lot of heat.
I'm not sure if it was turned on (it shouldn't have been), but keep in mind the top speed is 10K RPM, with the amount of wind resistance, just backing off the throttle will create some sort of braking effect.
Maroon looks good on you ;)
Ha, thanks ;-)
Any value in making the weapon more aerodynamic?
Possibly, but it COULD be at the expense of hitting force. Don't worry, I will show you how I cut down the current draw to significantly less. I have it down to 23A, and I should be able to get it even lower with a quicker spin-up time.
Hmm nice
I would make the blade smaller so it has less chance to hit the motor.
Yeah, that narrow clearance worries me too.
Nice to know someone shares my concern.
I may have missed it but is there an estimated budget for this build? I’m curious how much a bot of this size would cost to build sans sponsors.
It was in the first video, this is a beetle without a budget. I'm just trying to build the meanest horizontal spinner that I can build.
Awesome. Well you’ve got me hooked and I’ll follow this build for sure
Can't you Tormach some Uhmw for the pulley?
UHMW may be too slick to get a good grip on the belt
@@paulb8264 True, then what about High-Strength Glass-Filled Impact-Resistant Polycarbonate
its psychotic. it needs all the madness it can get.
Slightly off topic: All your recent videos look really washed out and green tinted. Did you by any chance switch to a different camera and forget to adjust the color grading in your editing program?
Yeah, I'm trying different grading. I just need to sit down and create a final profile, I'm not all that thrilled with this one, I just need to work on it more, but I'm spending too much time actually making stuff and haven't spent the time to change the grading.
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