Just to say hello

Community General Discussions
1

Hi everyone,
I am new to this forum, and I think it is appropriate to indroduce myself.
I am a 43y/o German, working in the IT-dept. of a large insurance company (yeah, yeah, I know…). That means I don’t have to watch my spelling all that much… just kidding.
I have a wife and 2 kids (almost 10 and 12), and besides all that I like to build things, preferably something mechanical.

Robots have always fascinated me, and I still have one of the original Fischertechnik robot arms from way back in the 1980ies, and an old Omnibot2000 (who is actually looking for a nice family who would adopt him).
As for mobile robots, I have built a number, with changeing success. Those where all wheeled/tracked chassis based. I also built a few bugbots, like photovores etc.

A few years ago I got into building multicopters. I have a small, old and battered CNC mill (Step4-400), so I am in the lucky position to be able to make some of the parts myself (like the frame in my avatar-picture). One of the goals here is to have a stable platform to loft a camera and take aerial images. That’s what I did during my time in the military, so I guess it came naturally.

Unfortunately, my programming skills are quite limited. I do understand most of the code when I read it, but designig my own beyond the structural graph is something different.

I do think that I am not all that bad when it comes to mechanical engineering.

I have been following the various developments of leged vehicles on and of. I tried my own project (a bucket full of servos, some hours on the CAD, ond then letting the mill scream away…), but I decided that I would be better off reusing an existing electronics package rather than re-inventing the wheel.

So, I will do some reading-up on what’s keeping you folks up all night, and probably come out of that with more questions than I have now.

2

Welcome to the forums. I have a small mill also but I patiently await for the money to buy the CNC components to make it do what I really want it to. I play around with the manual operations, but anything beyond straight lines is more than I can handle. :laughing:

I look forward to seeing some of your stuff.

3

Mike,
thanks for the friendly welcome.

If you like, I can point you to a guy who made a CNC mill from 1by2s and drawer rails, and you can also see what incredible stuff falls off that!

What I made so far is basically shown here:
qc-copter.de/forum/viewtopic.php?f=10&t=4
I have to put that on a nice homepage. Sometime. When I am done with the other 354 hobbies…
What you see is airplane-grade plywood, 1.5mm carbon-fiber-compound, F54 alloy aluminum (not nice to work with), and glass-fiber-compound (PCB-base without the copper layers).
I have yet to build some kind of mill dust removal. What I do now is follow the mill head around with a vacuum cleaner.

I am drawing with SolidWorks 9, exporting to DXF, turning that into G-code using CamBam, then run the mill from an old PC running a special Ubuntu (with realtime-extensions) with EMC².
That comes as a ready-made distribution. It took about 2hrs to set up the mill, and I am quite satisfied with that. I never had a motor missing a step so far.

4

Welcome. Your heli work is really impressive. Have any videos on youtube?

5

I love the design work that you have done. Very nice work. There were many different designs you had on the web page and they all look really good.

6

Thanks!

Actually there are some videos on both youtube and rc-movie.com
[secret]
I am in the office and those video platforms are blocked, so I can’t give you the links right now
[/secret]

So, just search for “Bogoframe” (which is the pseudo-brand-name I use for the frames) o these platforms.

BTW: this is my latest design, laser-cut from F54 alu:

I’ll make you a deal:
You’ll help me get my hexapod “up and running” (yes, pun intended), and I’ll help you get a multicopter in the air.
Those things do autonomous stuff - like keeping level by gyros and acceleration sensors (3 axis each), keep height (pressure sensor fused with “up”-ACC-value), plus GPS position.
You get telemetry, on a nice airplane-dashboard-like GUI, and also in your video googles on an OSD (interlaced into a camera signal from the bird).

All software is free, part of it is even Open Source (not as much as we used to have, due to strong bootleg activities in a land with a big rice consumption).

Like I said earlier - I am not a good programmer. I’d rather team up with people who are, and let them do that, and they let me do the airframes.
Also, I’d rather design my own stuff and get some ROI on my mill, than buy parts that I can easily cut myself.
Before we hit any missunderstandings - I am not in the business of designing and making a business out of the parts. I don’t even have the time to make more parts than for my own use, much less run a shop, with book-keeping, IRS and whatnot. That time spent would be more productive driving a forklift at a wallmart warehouse!

7

A laser cutter? Those are expensive! The picture of the aluminum air frame is my favorite of all the other designs. It looks awesome! I’m with you about the programming. I can write IF-THEN-ELSE code but that’s about it. When it comes to algorithms or nested loops, I’m lost. I’m like you where I enjoy the design work more than the code development. :smiley:

8

Cool parts! The assembly looks to be made from pretty thick material. It seems as if it could be made from thinner material and still be strong enough for the purpose. Do you think it could be made with thinner material and still be strong enough?

9

I can cut that on my mill, but the aluminum is a problem. It needs a lot of fine tuning for feed speed and rpm, or the stuff “smears” into the mill bit.
The alu stuff was a “contract” construction job from a guy who is selling them. He has a contractor who does the laser cutting (they cut 2" of steel. This alu stuff is peanuts for them). The cost is gross material plus time on the laser, which is mostly coolant consumption for the laser tube.

The material is 1.5mm always. It’s because I sometimes use alu, and sometimes fiber compund (I don’t have to redraw everything or parametrize the CAD-files like crazy). Also, it is an issue of availability.

It is OK for the compund materials, and actually a bit thin for alu. You are absolutely right that weight is the most important consideration, because the thing is supposed to fly. However, torsion stiffness is also quite important, or you will get yaw motion in power climbs. To give you an idea: on an average motor/prop combination (one on each arm) using a 10" prop that is 1" above the motor mounting plate, a hard shift in prop torque will create something like 2½lbs/in of torque (converting from metrics here…).
Keep in mind that in order to hold the copter level (or at a give angle), you have 30-60W shifts in power constatly on any given arm. That’s the IMU doing, and it is worse the heavier the propeller is, or the more load is on the props.

The quad in alu is about 230g, the 3-axis 170g (7½oz and 5½oz). In fiberglass about half of that.