Register To Comment
Page 2 of 2 FirstFirst 12
Results 11 to 20 of 20

Thread: Crumbs! (And Friends) - Team Manuva's Antweight Build Log

  1. #11
    Ocracoke's Avatar
    Team Kaizen

    It is looking mighty neat in there, well done! For posts, couldn't you fill in four corners of the print a little and use something like a M2 self tapper to hold a lid down with? To save weight, might be worth shortening the wiring a bit?
    Team Kaizen - Build Diary for all the robots

    AW: Amai, Ikari, Lafiel, Osu, Ramu
    BW: Shu!, The Honey Badger
    FW: Azriel
    MW: Jibril, Kaizen

  2. #12
    McMullet
    Guest
    Quote Originally Posted by Mr Manuva27 View Post
    Positives


    • Motor mounts fit perfectly


    Negatives

    • Wheel gaps are too tight and exposed
    • Not much extra space
    • Print quality is awful.
    • I absolutely hate it.


    That last point made me chuckle.

    The new Crumbs looks really nice, very impressive. Good plan on using F360 too, I was also a bit incredulous that they let us use it for free!

  3. #13
    Mr Manuva27
    Guest
    Bit late, but Crumbs is done.... kind of. This whole build has given me a new respect for those who have antweights as their "main class", because this has been so awkward and fiddly to build. Probably a large portion of that is due to my design choices, but still.



    Lifter gears have been put in place and the lifter works. The lifting arm itself is just some leftover 1mm stainless steel I have from the toaster on Bread Dead. It doesn't lift much, just kind of waggles. I think the pivot is too far forward to get proper leverage. Looks cute though!

    Had some issues with the gears slipping, but that was solved with a larger lifter axle and printing the servo gear 1mm bigger.

    Printed some top panels, then it was time for a test drive!



    So Crumbs is fully functional. It weighs in at 142g, so may use the final few to redesign the top panels so they print better.

    IMG_20200520_210552.jpgIMG_20200520_204743.jpg

    One final development is that I have managed to get my hands on one of BBB's beta sale of the new Malenki-Nano Rx/ESC, which can drive 3 channels and replace both the Rx and ESC all on one 2.6g board. I'll fit this to Crumbs eventually (key word being eventually. I have a big project to be working on soon. More on that later....), but this will save a lot of weight that could be used for reinforcing the front with more stainless and changing the lifter servo out for an N20 for extra lifting power.


    Link to the Malenki-Nano specs if anyone is interested, they are planning more stock soon.
    https://shop.bristolbotbuilders.com/product/malenki/

  4. #14
    Ocracoke's Avatar
    Team Kaizen

    Looks awesome, well done! I do like the look of the lifter mechanism, even if it isn't the most effective. I guess the only way to test it is to try and lift 150g+. I know Ikari can lift that much with a similar forward pivot, just awkward to get underneath opponents due to the shape.

    This whole build has given me a new respect for those who have antweights as their "main class", because this has been so awkward and fiddly to build. Probably a large portion of that is due to my design choices, but still.
    Indeed, I struggle to build Ants for relatively similar reasons. Takes a few goes with a Dremel and a steady hand to get it right :P
    Team Kaizen - Build Diary for all the robots

    AW: Amai, Ikari, Lafiel, Osu, Ramu
    BW: Shu!, The Honey Badger
    FW: Azriel
    MW: Jibril, Kaizen

  5. #15
    McMullet
    Guest
    The flipper looks great! Agreed on the fiddliness of building ants. I think the layout will get easier after a few goes but I'm also struggling with the tiny solder pads.

    I saw the nano ESCs on the BBB shop, it'll be good to see your test run. For our ants I've come up with a halfway house using one of these taped to the standard dual-channel ESC. Saves the weight of the wires and connectors at least!

  6. #16
    Mr Manuva27
    Guest
    So BotFest was due to happen a few months ago, but was unfortunately cancelled due to lockdown. I had redesigned Crumbs! to improve the lifter as the servo driven one didn't have enough power.

    I always wanted to build a 4-bar lifter but kept it under wraps until the event. When it was cancelled, I lost a lot of motivation to work on it and it sat in my Fusion360 files for a few months, until last weekend!



    The arm is now powered by a 100rpm N20 rather than a servo, plus a 300mAh 2S battery.

    It needs reprinting at a thinner layer thickness before it is truly combat ready, plus superglueing a stainless steel beak (leftover from BDR) to the front arm. Regardless, I'm super happy with it.

    Hopefully events get back to normal sooner rather than later so I can take it for a proper test run!

  7. #17
    Ocracoke's Avatar
    Team Kaizen

    Yeah, I hope I get to see this soon, love the arm action! I've been cleaning out the shed here and found the BotFest arena in there, sitting there ready to go.
    Team Kaizen - Build Diary for all the robots

    AW: Amai, Ikari, Lafiel, Osu, Ramu
    BW: Shu!, The Honey Badger
    FW: Azriel
    MW: Jibril, Kaizen

  8. #18
    McMullet
    Guest
    Looking great Andy, I'm also working on an antweight 4-bar lifter (very much languishing in work-in-progress CAD though).

    Do you have a way to stop the motor when the lifter gets to the end of its travel? I was planning on using a servo to stop it damaging itself, but it doesn't seem like a great power-to-weight ratio whereas that is super fast, looks more like a flipper than a lifter.

  9. #19
    Mr Manuva27
    Guest
    Yeah, I hope I get to see this soon, love the arm action! I've been cleaning out the shed here and found the BotFest arena in there, sitting there ready to go.
    Thanks! Really pleased with how the arm movement came out. I still need to adjust the horns at the back so it can self right, but aside from that it's perfect. Fingers crossed we get the all clear to fight again soon.

    Do you have a way to stop the motor when the lifter gets to the end of its travel?
    I do! It's called the floor . Because my transmitter has both sticks on spring return, just a quick burst of the motor is enough to get full extension. Don't think it's enough to burn the motor out, but proof of the pudding shall be in the eating.

    I was planning on using a servo to stop it damaging itself, but it doesn't seem like a great power-to-weight ratio whereas that is super fast, looks more like a flipper than a lifter.
    Servo should be fine. It's worth noting that a 4-bar arm requires different force depending which end is powered. The "crank" (rear arm) takes less force to lift than the "rocker" arm (front). If you're worrying about a servo not having enough power, you'll be better off linking it to the back arm. It should be sufficient. I'm only using an N20 because I'm using a Malenki Nano ESC, which works better for motors than servos.

    If you're making a 4-bar, I recommend the AskAaron blog and geometry calculator/excel sheet for it. Took lots of trial and error, but was worth it in the end.

    http://runamok.tech/AskAaron/lifter_FAQ.html

  10. #20
    McMullet
    Guest
    I've spent FAR too long playing with the spreadsheet. Happy with that part, just messing around with the infinite design space of 3D printing now...

    Quote Originally Posted by Mr Manuva27 View Post
    I do! It's called the floor . Because my transmitter has both sticks on spring return, just a quick burst of the motor is enough to get full extension. Don't think it's enough to burn the motor out, but proof of the pudding shall be in the eating.
    That's a good point. I was assuming I'd just stupidly hold the stick down with the motor stalled but in reality I'd probably be able to let go after a second or so... N20s look like a better power to weight than a servo.

Register To Comment

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •