Shop Learn
Artie Max by Erco (Braggin' a bit) — Parallax Forums

Artie Max by Erco (Braggin' a bit)

ercoerco Posts: 19,994

This was just a freelance job ( no royalties, dangit) but it was a fun project earlier last year. I love getting paid to build robots! They pretty much kept my original design (tricycle front wheel drive & steering) and all my features (pen changer turret, line following, color sensing, edge detection). And now that the company Educational Insights has announced it, I can share some of my early prototype tests. I hope they can execute in production!

My prototype demos & tests:

Comments

  • Wow! What beautiful engineering and impressive precision! Congrats, Erco! That little beastie is amazing!

    -Phil

  • Take my money! TAKE MY MONEY! :)

    Very well done, Erco.

  • PublisonPublison Posts: 12,060

    Way to go bro!

  • Hi

    That's brilliant!
    Spill the beans- how do you get that degree of precision? Is it dead reckoning or is there something else going on? I just can't see how errors don't start to creep in after drawing a few shapes.

    Dave

  • ercoerco Posts: 19,994
    edited 2021-08-27 16:49

    It's all dead reckoning, no trickery going on. The steering servo's accuracy & repeatability is critical, obviously.

    Here's my first handmade prototype drawing 6-rings in color.

  • ercoerco Posts: 19,994

    The most complex image I coded was this simplified cat above, vs what the client sketched below. I can't find a video of drawing that one right now.

  • This is seriously cool

  • Those skinny tires are the key to accuracy. Ignoring traction, the smaller the contact area with the surface, the better.

    -Phil

  • PublisonPublison Posts: 12,060
    edited 2021-08-28 18:22

    @"Phil Pilgrim (PhiPi)" said:
    Those skinny tires are the key to accuracy. Ignoring traction, the smaller the contact area with the surface, the better.

    -Phil

    Agree. I think the Rubber Band tires are the key.

  • Hi

    I believe it has a steerable front driving wheel "(tricycle front wheel drive & steering)" which we cannot see. So the large wheels at the back just 'follow' the front. So that means the steering must be VERY precise- yet it 'looks' to only be a servo, which I would not have thought would have that degree of accuracy- unless its a digital servo maybe? That must also go for the single driving wheel itself; I would think they both need to be accurate to a degree- or even better? I'm just amazed at the precision- I'll keep guessing.

    Dave

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,052
    edited 2021-08-28 21:25

    I believe it has a steerable front driving wheel "(tricycle front wheel drive & steering)" which we cannot see. So the large wheels at the back just 'follow' the front.

    That doesn't sound right to me. The pen has to be at the center of rotation, which is true if the rear wheels are powered and steer differentially. But Erco might've figured something out that evades me at the moment.

    -Phil

  • ercoerco Posts: 19,994
    edited 2021-08-28 23:00

    Yes, just one steerable driven wheel up front, the rear wheels are unpowered and just follow along. Pen drops exactly midway between the front wheels. Chassis pivots around the pen contact point when steering servo turns exactly 90 degrees left or right of center. Only one encoder to read, you know what a simpleton I am! You can see the drive & steering mechanism (top cover removed) in the NUT video above, 5th video down from the top.

Sign In or Register to comment.