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Cyborg Swerve 9.0

samthesnake

By: samthesnake
New: 09-10-2017 07:11 PM
Updated: 09-10-2017 07:11 PM
Views: 1065 times


Cyborg Swerve 9.0

One of our new Cyborg Swerve 9.0 modules. I will try and get the whole assembly done this week. It weighs a little over 4.2 lb, and it uses bevel gears from sdp-si. Steering is on a custom bearing similar to ones used by turrets. Wheel is custom with a diameter of 2.6 inches. We recently acquired a very capable machining sponsor. Goals were to decrease weight and programming complexity.

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09-10-2017 07:33 PM

Chak


Unread Re: pic: Cyborg Swerve 9.0

  • Why belts?
  • Are you sure you have sufficient belt wrap on the pulley between the 775pros, if you're using a single belt for the whole thing?
  • What are you planning for the encoders?
  • Do you plan to 3D print the rotating part? (the one with the wheel inside, I call it the "caster") I'm guessing based on the fillets on the part. If you are, it seems like there are several ways to print it stronger.
  • Why stick with hex shaft for dead axle? Seems like you can save a marginal amount of weight by using circular shaft.
  • Can you post a better picture of the bearing setup?

Thanks for sharing your design!



09-10-2017 10:02 PM

samthesnake


Unread Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by Chak View Post
  • Why belts?
  • Are you sure you have sufficient belt wrap on the pulley between the 775pros, if you're using a single belt for the whole thing?
  • What are you planning for the encoders?
  • Do you plan to 3D print the rotating part? (the one with the wheel inside, I call it the "caster") I'm guessing based on the fillets on the part. If you are, it seems like there are several ways to print it stronger.
  • Why stick with hex shaft for dead axle? Seems like you can save a marginal amount of weight by using circular shaft.
  • Can you post a better picture of the bearing setup?

Thanks for sharing your design!
1. The module was wanted to be longer and not a square in order to potentially fit a larger intake or similar mech. Gears needed would have been overly bulky and awkward
2. Not sure your meaning. There is space between the two pulleys both on top and on bottom, if that is what you mean
3. Versaplanetary integrated encoder on a 1:1 pulley ratio a la Stryke Force. Also a backup hall effect sensor I do not have modeled
4. We may end up making it three pieces bolted together like we did last year. I have not consulted my 3D printing expert yet, nor have we decided what printer we are going to purchase
5. We have a bunch of hex stock and hex bearings, but I guess I could have slimmed the wheel down a bit more and used a smaller shaft, you are right
6. Like this except smaller. It surprisingly worked super well last year for us.

Thanks for the questions. Like I said it will look better once I mount it to a frame and bellypan.



09-10-2017 10:19 PM

Chak


Unread Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by samthesnake View Post
2. Not sure your meaning. There is space between the two pulleys both on top and on bottom, if that is what you mean
I meant for the pulleys that make up the first stage from the 775pros.



09-10-2017 11:30 PM

samthesnake


Unread Re: pic: Cyborg Swerve 9.0

Yes I am sure



09-11-2017 12:37 AM

marcusbernstein


Unread Re: pic: Cyborg Swerve 9.0

Chak is talking specifically about the belt's wrap around the pulleys. To make sure the belt doesn't skip (among other things above my paygrade), it's important to make sure the belt has sufficient wrap around pulleys, especially those as small as 12t like the one you've used. If you want to understand wrap, think about how many pulley teeth the belt is contacting at once. The more teeth the belt is contacting, the better spread the load is and the better engaged the belt is, making the mechanism much less prone to skipping.



09-11-2017 01:17 AM

samthesnake


Unread Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by marcusbernstein View Post
Chak is talking specifically about the belt's wrap around the pulleys. To make sure the belt doesn't skip (among other things above my paygrade), it's important to make sure the belt has sufficient wrap around pulleys, especially those as small as 12t like the one you've used. If you want to understand wrap, think about how many pulley teeth the belt is contacting at once. The more teeth the belt is contacting, the better spread the load is and the better engaged the belt is, making the mechanism much less prone to skipping.
I did think about this. There is a 3/8 hex shaft pressed onto the 775 and an 18 tooth pulley instead of the 12 tooth pinion pulley. The pinion pulley is out of stock constantly, so I went with a larger pulley for that and to get more teeth in contact with the belt.



09-11-2017 02:02 AM

asid61


Unread Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by samthesnake View Post
4. We may end up making it three pieces bolted together like we did last year. I have not consulted my 3D printing expert yet, nor have we decided what printer we are going to purchase
If you have yet to even purchase a printer, don't rely on 3D printed parts coming out correctly unless it's medium-high end like an Ultimaker or Markforged.

What free speed are you geared for? With a single 775 you're looking at more risk.

Lazy susans are liable to blow up spectacularly. The one you linked seems more robust than most though so you may be ok.



09-11-2017 01:11 PM

samthesnake


Unread Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by asid61 View Post
If you have yet to even purchase a printer, don't rely on 3D printed parts coming out correctly unless it's medium-high end like an Ultimaker or Markforged.

What free speed are you geared for? With a single 775 you're looking at more risk.

Lazy susans are liable to blow up spectacularly. The one you linked seems more robust than most though so you may be ok.
We are just deciding between an Ultimaker and a Markforged.

14.5ish free speed - we may end up making this slower but this is about the fastest it will be.

We had no problems with that lazy susan last year. We did have problems with a poorly made McMaster one with a different design.



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