Dyne's LD-F1 (D-O concept) build

[Dyne]

T-Minus 8 weeks

As I write this, I now have exactly eight weeks remaining to get this build to a functional state (with a week of wiggle room/recuperation afterward before it's time to pack up for Dragon Con).  Things are starting to come together on the design (assuming I can stop breaking the timeline).  My checkpoint for "finishing" the design is this coming Thursday.  

It doesn't really have to be totally finished, because I can wrap up any remaining bits while I'm waiting on the printer.  For example, I calculated that my original rollers would take just a bit under 10 hours each, and there are six of them, so that'll be nearly 1.5 workweeks of printer time alone.  (I've made them shorter now, but still.  Once I get the axle/bearing setup finalized, I'll probably start printing those.  My friend has offered to help with his printer as well so it won't really be a problem for the schedule.)


I have done a lot of work on the upper portion, with the front, left, and top of the head and the antenna almost completely modeled.  (I get to make up the rest of the exterior because it isn't seen in the art.)

One idea I briefly toyed with was giving the lens a holoprojector-like mechanism, but I decided that was a bridge too far.  I am, however, still planning on having the antenna raise/lower via servo, possibly have an LED on the tip, and I'm strongly leaning toward making the panel on the top of the droid's head open.




I've also got what I hope is the final design for the head animatronics (assuming that they don't require further revision after testing).  I made them more vertically compact, which will help get the axes for the head rotations closer to the center of mass.  (Speaking of mass, when I weighed one of my earlier prototypes, it came in at roughly 327 grams.  That bit of it is probably slightly lighter now, but there are also now a few more parts.




In Fusion, it looks like the mechanism is clear to get roughly 58 degrees of rotation to either side before the parts might collide with each other, for a total of 116.  I'd love to get 360 or even 180, but that would require a complete redesign so that the rotation servo is either fully above or below the rest of the mechanism, and there's not a lot of room in here.  On the pitch (raise/lower) axis, I can probably get around 25 degrees from horizontal in either direction (a little more when pitching down), and I believe it's capable of tilting the head to either side by 15 degrees.  

These limits may need to be adjusted once I see whether anything is interfering (e.g. whether the head itself hits the mechanism or the stalk; or when the servo horns are rotated down too far , they may hit the rotation platform or screws if the head rotates).  After I print the latest version of the blue tilt arm for the animatronic assembly, that will hopefully be ready for a real test.


I am not neglecting the body of the droid ... the chassis CAD is a bit behind schedule, but I've done the placement for the motors and so forth, worked out some of the mechanics for the lift system, and rebuilt some of the aesthetic work from my draft model.  I also started feeling like 5 inches for each track was too wide to match the proportions of the artwork, so I reduced it to 4.5 (shortening the rollers in the process, as mentioned above).  Here's a comparison of the old and new proportions...








Side view with placement of lower lift arms.  Looks like I'm not getting away with a full body axle on the middle wheel.




Most importantly, however, I have already begun printing and testing, which I wasn't scheduled to begin until next month.  I've already made a rig to mock up the drivetrain (at least motor and pulleys, controlled via PS3 Nav controllers by Penumbra on one of my ESP32s), and printed the associated belts, which work fine after cleaning off some of the stringing-induced blobs.  I'll need to reprint them to change the diameter, but I'm confident they'll work.





I have also printed the first major externally visible part (the stalk section from my previous post) part and performed a dry fit, complete with the threaded rods and the head servos.   It's a pretty beefy part once the rods are installed, with 5 perimeters.  Once I cut my threaded rods down to the correct lengths, I can begin the real assembly and preparation of the part (it will be a pain to sand smooth).  



I was going a bit too fast on that print on the upper end, I think.  I've slowed it down since then.


In terms of the upcoming schedule, I tend to write my "checkpoints" for Fridays so I can triage the preceding tasks on my days off if I need to pick up the pace.  This is what it currently looks like:

• 2022-07-01 - Checkpoint: Begin printing (I'm slightly ahead of schedule on this)
  
• 2022-07-08 - Checkpoint: Print the treads! (They'll take a long time and I have to get the size and tooth profile correct.  Which reminds me, I need to get on ordering additional Grey TPU.  Micro Center is still out, but I have an alternate in mind.)
  
• 2022-07-15 - Checkpoint: Begin assembly and wiring (technically I've already started this)
  
• 2022-07-22 - Checkpoint: Finish printing (at least the big stuff)
  
• 2022-07-29 - Checkpoint: Begin testing
  
• 2022-08-05 - Checkpoint: Begin painting
  
• 2022-08-19 - Goal: Fully painted, tested, and assembled
  
• 2022-08-23 - The final week before con begins.  You should be done by this point so you can rest.
  
• 2022-08-26 - Last weekend before con.  Get anything big done NOW!
  
• 2022-08-29 - Absolute last day for droid building
  

Busy Busy