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View Full Version : [Project] Andy - just another hexapod (newbie)



ActiveHouse
03-12-2008, 04:46 PM
Hi folks,

First of all, let me shortly introduce myself. My name is Kris, I'm a 34-years old business analyst (formerly a software-developer) from Belgium.
About a year and half ago, I started growing interest in electronics. Last year my wife bought me a small CNC machine as a christmas present. (the colinbus profiler from elektor)
The main goal of this machine, was to mill PCB's, but I allready had some other ideas in mind.
(I allways had an affinity with robotics, I own several lego mindstorms sets (about 6 RCX bricks and one NXT set, with lots of extra sensors)
Because I start to feel the need to "automate" some things in life, with not only electronics, but also partly mechanics, I discovered this forum.

As a first "tryout", I ordered 20 Hitec servo's from TrossenRobotics, and I started drawing in Autocad, greatly inspired by "Phoenix" ;-)
The result is an hexapod, consisting of 18 servo's, and only self-made parts, (out of plexi) and lots and lots of screws, bolts and nuts ;-)

There is no electronics yet (I'm also planning on building this myself),
but the mechanical part is mainly done.
Have a look at the following pictures:
http://cid-59e7d8d59f47de4c.skydrive.live.com/browse.aspx/Robotics/Andy%20-%20Hexapod/Pictures

- overview_1.JPG is a general overview, with the body in the highest position.
- overview_2.JPG is a general overview, with the body in the lowest position.
- the little spider and spiderweb that you see in top_detail.JPG, are taken from the windowsfont
"webdings" (characters "3" and "8")
- on leg_back.JPG and leg_bottom.JPG, you can see the backside of the servo's.
I did take out the 4 screws of the servo, and "sandwiched" my backpanels between those
screws and the backpanel of the servo.
I did make the servo-brackets "modular", so I can use them in future projects. That is why
you see 2 bolts (I hope this is the correct word ? I mean the 6-sided piece of iron)
on the backside. No matter which direction you place the servo in the bracket, it will always
have a bolt on the opposite site of the actual servo-shaft.
On the side of the bracket are 4 holes, evenly separated horizontally and vertically, so you
can attach another brackt in any direction.

People interested in the autocad files, can have a look at:
http://cid-59e7d8d59f47de4c.skydrive.live.com/browse.aspx/Robotics/Andy%20-%20Hexapod/Autocad%20files

And people who own a colinbus profiler CNC machine, can download the "ready to mill" files from:
http://cid-59e7d8d59f47de4c.skydrive.live.com/browse.aspx/Robotics/Andy%20-%20Hexapod/Colinbus%20Profiler%20files

Any comment is welcome, and since this is an ongoing project, I will surely post more info and pictures in the future.

P.S. Sorry for my bad English, Dutch is my native language.


Best regards,
Kris

Zenta
03-12-2008, 05:18 PM
Hi!

Nice work! It seems like your work also has some Lynxmotion BH3-R inspiration (body design). Very clever done with you custom brackets. Overall very good work!

Q: What kind of servos are you gonna use, it seems like you are using 322 for the coxa (HipH) part, but what about the femur (HipV) and tibia (knee)? 645 or 475?

Keep up the good work!

DresnerRobotics
03-12-2008, 05:51 PM
Excellent custom built hex!

I like the clear plastic used, is that lexan? Would make a cool platform to mount LEDs into to make the frame glow :D

What sort of servo controller/brain did you have in mind? You said you were going to build custom, but I'm curious as to what IC you were planning on using. The Atmega chips are a great platform all around.

Very cool of you to post all your CAD work and whatnot, thanks!

PS: Your english is great! I wouldn't have known it wasnt your native language had you not mentioned it ;)

ActiveHouse
03-13-2008, 03:25 AM
Thanks for the nice replies ;-)

- I only have HS322HD servo's for the moment, for testing purpose.
(I put Andy on a box, with his legs in the "air" to program him)
I will see how those servo's work out, and will replace them in the near future with 475 probably.
- The round design was "a request" from my wife, I like the Phoenix-look better, but I can
allways change the body afterwards ;-)
- I think the clear plastic is lexan, they call it "plexi" at our local DIY-shop.
(I'm surely planning some RGB LEDs, lol, I'm a LED-addict)
- I started using microchip PIC's about a year ago, so I think I will stick with that.
an 18F4680 will do, because is does have lots and lots of memory ;-)

I'm thinking of adding 3 ultrasonic sensors to the front and to the back of Andy,
a compass-sensor, a CMUCAM3, an accelerometer sensor, some RGB-LEDs,
3 LDR's at the front and 3 LDR's at the back, 4 MIC's (for direction sensing of sound)
and, a small LED matrix for his face, and a "text to speech" interface ;-)
The idea if to have Andy running in 2 modes:
- Standalone mode:
Depending on light, sound and "environment", Andy will change his "mood".
He will crawl independantly trough the house, attack guest who sneek up behind him,
avoid obstacles, follow objects or people etc ... Also,
when his battery is allmost empty, he will look for his loading station.
- Human-driven:
I will have a control box, with an LCD, which shows the images of the CMUCAM3,
overlayed with parameters (direction, battery level etc) and menu's (select some pre-defined
movements, select some sentences that Andy can say) if needed. (OSD)
a couple of joysticks, a small 16-keys keypad and a microphone will be the finishing touch.
(all this will be put in a very small flightcase, 30x20x10 cm
So Andy can fully be controlled by a human ;-)
All of this offcourse wireless (I'm still in doubt which "system" to choose, WIFI or bluetooth)

So, lot's of ideas, but due to my regular visit to the hospital for my HHC (some sort of cancer),
it will probably take more then a year to complete Andy ;-)


best regards,
Kris

Alex
04-21-2008, 10:33 AM
First of all, let me shortly introduce myself. My name is Kris, I'm a 34-years old business analyst (formerly a software-developer) from Belgium.

Welcome to the TRC Chris!


Last year my wife bought me a small CNC machine as a christmas present.

You are one lucky man!


Because I start to feel the need to "automate" some things in life, with not only electronics, but also partly mechanics, I discovered this forum.

Very cool. I hope you can share your experiences with all of us:D

Adrenalynn
04-21-2008, 03:06 PM
Very cool custom project!

Just for your own knowledge, "plexi" is "plexiglass" - which is another way of saying acrylic, which is a synthetic polymer of methyl methacrylate. It's a "soft plastic"

LEXAN (a registered trademark of G.E.) is a "hard plastic", a polycarbonate resin thermoplastic. It's hugely tougher than "plexi", and is used to make bullet-proof "glass", CD's, DVD's, aircraft canopies, ...

It's also tremendously more expensive.

I've worked quite a bit commercially (and as a hobbiest) with both. If you need tremendous strength, go for LEXAN, otherwise, Plexi is probably just fine.

4mem8
04-23-2008, 06:39 AM
Activehouse: That's one neat design, very unusual looking at clear acrylic for a hexapod. Good work.