After printing the Maker Figure my son and I sat down to design our own robot. During our concept generation session it quickly became apparent that my son, who is four, was asking me to design a robot that looked very similar to one from a video game he had seen. With that drawing as a template we built a few prototypes of the body and legs before settling on the parts that have been uploaded. According to my son, "It's perfect, exactly what I wanted." We hope the maker community enjoys it as well.
- Sonoranguy Modified the feet to remove the rotating claws. The rotating claws can be flimsy which this would fix.
- Guardian Leg Segment Check out this improved version of the guardian leg. It no long snaps in, but looks much closer to the original.
- Geirskogul Do not use carbon or transparent ABS for the leg segments. Transparent ABS has acrylic in it and it too brittle.
- Hackable - This remix provides a bunch of space and hooks for electronics such as LEDs and servos.
- Details Separate - This separates the details and the robot body to allow for dual extrusion printing.
The PCB Workstation with Articulating Arms provided the inspiration for the robot arms.
My goal was to print the robot in as few parts as possible while ensuring that all of the joints printed cleanly.
I kept kept the hip joints as part of the body, even though the resulting hips were looser then desired, because I liked the integrated design and the challenge of printing everything in a single shot. The head rotates in the same manner as the Maker Faire bot. To improve print time and material usage, I hollowed out the model being careful to minimize overhangs. Most of the model has wall thicknesses of 2-3 mm where possible.
The arms took a few tries to get right. I ended up printing the arm segments separately so that the sections could be snapped in for a tighter fit than would be possible if they were printed in a single shot. Finding appropriate dimensions for the engagement required trial and error to find segments that did not fall apart easily and still rotated smoothly. Variables to consider here were the wall thickness, engagement depth, and ball diameter. The claws use simple cone hinges providing smooth motion.
Print 1 Body, 6 Claws, and 90 Segments.
I used a raft and no support to build these parts. The Segment is printed with the ball rotated to be on top and the Claw is rotated to be printed with the claw on the bottom. Print the body with the head rotated to be on top.
Once printed, the head and hip joints rotated smoothly with minimal sticking.
I've uploaded body_120dia_botwg which should allow the Guardian to be printed on a bed with dimensions of 120 x 120 x 120. This was modified by cutting a small portion off the OD of the original.
Reducing the size may cause the parts to freeze or prove brittle. I used a minimal gap to allow the parts to rotate and a minimal wall thickness to conserve material.
As with any project, there is always more to do an improve upon. Here is a my current list.
- Complete I left the arms hollow for the potential to add a string or elastic band.
- Complete Increase the claw size (almost double).
- Complete Create a model with snap in hip joints to provide more friction. [I built this and it worked... however the model required significant tweaking from standard print settings. In order to keep this easy to print, I removed this feature. You can freeze the hips in place with a dab of super glue.]
- Complete Add an access hatch to the head and or base for electronics (LEDs) See this remix.
- I need to redesign the claws to be more robust. The current hinge fails to easily.