A Simple 3D Printed "Walking" Mechanism.

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Introduction: A Simple 3D Printed "Walking" Mechanism.

About: Our grandkids keep me busy!

I truly enjoy mechanisms, thus when a recent YouTube video appeared in my YouTube suggested video feed of a CAD animation of a simple walking mechanism designed by thang010146 (https://www.youtube.com/watch?v=1ht3nz4YgGY), I just had to try to recreate his mechanism for 3D printing.

thang01014's mechanism was designed to be powered by torsion springs or rubber bands, but I decided to design a motorized version. After a long afternoon of design, 3D printing and assembly, "A Simple 3D Printed "Walking" Mechanism." was the result. And as indicated in his video, the mechanism indeed powers over "rough" terrain with ease. Since originally publishing this model, I modified "Side.stl" to include a "sawtooth" edge for better traction over rough terrain, the new file is "Side, Sawtooth.stl".

My implementation of his design consists of eight unique 3D printed parts (twenty six total 3D printed parts as there are numerous duplicates), a motor, battery and battery connector.

For those such as I who truly enjoy mechanisms, I highly recommend checking out thang010146s website, his work is outstanding!

As usual I probably forgot a file or two or who knows what else, so if you have any questions, please do not hesitate to ask as I do make plenty of mistakes.

Designed using Autodesk Fusion 360, sliced using Cura 4.7.0, and 3D printed in PLA on an Ultimaker 3 Extended and Ultimaker S5s.

Supplies

  • Double sided tape.
  • Thick cyanoacrylate glue (if necessary).
  • Solder and soldering iron.

Step 1: Parts.

I acquired the following parts:

  • One 3.7vdc 100ma Lithium Battery (https://www.adafruit.com/product/1570).
  • One JST PH 2-Pin Cable (https://www.adafruit.com/product/3814).
  • One N20 6VDC 100RPM gear motor (on line).

I 3D printed the following parts at .15mm layer height, 20% infill:

  • Six "Arm.stl".
  • Six "Axle, Side.stl".
  • Three "Axle.stl".
  • One "Base.stl".
  • Six "Bolt, Axle.stl".
  • One "Gear, Axle.stl".
  • One "Gear, Motor.stl".
  • Two "Side.stl" OR Two "Side, Sawtooth.stl".

Prior to assembly, I test fit and trimmed, filed, drilled, sanded, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on you printer, your printer settings and the colors you chose, more or less trimming, filing, drilling and/or sanding may be required. Carefully file all edges that contacted the build plate to make absolutely certain that all build plate "ooze" is removed and that all edges are smooth. I used small jewelers files and plenty of patience to perform this step.

The mechanism also uses threaded assembly, so I used a tap and die set (6mm by 1) for thread cleaning.

Step 2: Assembly.

To assemble the mechanism, I performed the following steps:

      • Positioned "Gear, Motor.stl" into "Base.stl", then pressed the motor into the base and gear.
      • Soldered the JST connector to the motor.
      • Pressed "Gear, Axle.stl" onto one of "Axle.stl".
      • Positioned the axle assembly in the base assembly, then secured in place with two "Arm.stl" and two "Bolt, Axle.stl".
      • Positioned the second axle in the base assembly then secured in place with two "Arm.stl" and two "Bolt.stl".
      • Positioned the third axle in the base assembly then secured in place with two "Arm.stl" and two "Bolt.stl".
      • Attached one "Side.stl" or "Side, Sawtooth.stl" to the base assembly arms on one side using three "Axle, Side.stl".
      • Attached the remaining side (or sawtooth side) to the base assembly arms on the remaining side using three "Axle, Side.stl".
      • Secured the battery to the base assembly using double sided tape.

      After assembly, I simply plugged the JST connector onto the battery connect, and off it went!

      And that is how I 3D printed and assembled "A Simple 3D Printed "Walking" Mechanism".

      I hope you enjoyed it!

      Make it Move Contest 2020

      Participated in the
      Make it Move Contest 2020

      4 People Made This Project!

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      23 Comments

      0
      carter.boland
      carter.boland

      Question 10 months ago

      If I plan to make this, can you give me a better name and brand of motor? I find tons of them with different sizes and brands.

      0
      gzumwalt
      gzumwalt

      Answer 10 months ago

      Hi carter.boland,

      There are a many manufacturers / suppliers of N20 sized gear motors, Pololu, Greatisan, and uxcell to name a few.

      For this model, I simply searched for n20 6vdc 100rpm gear motor and found them available at a variety of sources.

      Hope this helps!

      Greg

      0
      carter.boland
      carter.boland

      Reply 10 months ago

      Thanks. I have some other plans to do before this one (around 50 that I would like to do), and also school.

      0
      gzumwalt
      gzumwalt

      Reply 9 months ago

      Well keep us posted, I would like to see your results!

      Greg

      0
      LarryG7
      LarryG7

      10 months ago

      This is not an uncommon project. I would be imore impressed if you made the robot stand upright on two three jointed legs and walk as a human does.

      0
      jeanniel1
      jeanniel1

      Reply 10 months ago

      What a snarky comment! What happened with "be nice?" I think it's a worthy 'ible.

      0
      gzumwalt
      gzumwalt

      Reply 10 months ago

      Hi jeanniel1,

      At times I design simpler models for those learning CAD and 3D printing, and this model was one of those.

      While the comment from LarryG7 did not upset me, I receive plenty of "hate" mail for some of my designs, the latest begin my "Rarity" model (https://www.instructables.com/id/Rarity-a-3D-Print... that I designed for and gifted to a local waitress.

      One thing I've learned during my 65 years, you cannot please everyone!

      Greg

      0
      jeanniel1
      jeanniel1

      Reply 10 months ago

      AH, that is certainly for sure, Greg. It's hard enough publishing something - and folks can choose NOT to read it - move onward, etc. Glad you're a reflective and creative sort anyway!

      0
      LarryG7
      LarryG7

      Reply 10 months ago

      You're telling me to be nice? My comment was about as neutral as it can get.

      0
      gzumwalt
      gzumwalt

      Reply 10 months ago

      Hi LarryG7,

      This model is a 3D printed recreation of thang’s CAD model. In his video, there are links to others who have created mechanisms such as this using plastic, cardboard, etc.

      And regarding the three legged robot, so would I!

      Greg

      0
      ChrisR278
      ChrisR278

      10 months ago

      What method do you use to charge the battery? Thanks!

      0
      dan3008
      dan3008

      10 months ago

      To fix the traction issue you could add rubber feet or little "teath" on the bottom

      0
      gzumwalt
      gzumwalt

      Reply 10 months ago

      Hi dan3008!

      I've been on vacation, and upon return, I added a sawtooth pattern to the bottom of both sides. The Instructable has been updated with the new side (Side, Sawtooth.stl) and a new video.

      Many thanks!

      Greg

      0
      TobinHuebner
      TobinHuebner

      Question 10 months ago on Introduction

      What type/ speed of motor? The parts list states it is 150 RPM motor, the video text states it is 100 rpm. Which is it?

      0
      gzumwalt
      gzumwalt

      Answer 10 months ago

      Hi TobinHuebner,

      In the video, I used a 100RPM N20 gear motor but have used gear motors from 75 through 200RPM. All worked fine, it’s just how fast you wish to run the model.

      Greg

      0
      paolo3000
      paolo3000

      Reply 10 months ago

      Did you really feed a 6 V geared motor with a 3.7 V battery?
      Thanks
      Paolo

      0
      gzumwalt
      gzumwalt

      Reply 10 months ago

      Hi paolo3000,

      Yes, it’s perfectly fine. Like an electronic speed controller (ESC), lowering the voltage (or apparent voltage via pulse width modulation) slows the motor.

      Greg

      0
      studleylee
      studleylee

      10 months ago

      I like it!!!!!!!!