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Autonomous quadrocopter---setup and some questions

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rp181

Thu Mar 18 2010, 01:42AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

I am working on an autonomous UAV, and would like to make sure everything will work before buying.
For the UAV setup, I am doing a quadrocopter with the following parts, and a custom ABS or Nylon frame:
Motors: 4x

Props: 2x

ESC: 4x

Batteries:

Does this setup look good? Will it fly while being able to carry the payload listed below?

As for electronics,
I am thinking a beagleboard (plan on adding 3D image processing), with a sparkfun IMU (

Are these compatible?
I would also like to use a cellular module for remote control:

Questions:
1)Will it fly with that weight?
2)How do I send [serial] data to the cellular module? Do I have to use 2 cellular modules?
3)Anything I am missing?

cjk2

Thu Mar 18 2010, 03:19AM

Registered Member #51 Joined: Thu Feb 09 2006, 04:17AM
Location:
Posts: 263

Does this setup look good?

I will comment on what I can:
Those motors are a great deal if they work well. Most motors in that range are $40 and up.
The ESC's should be fine, once again, that is a really low price.
The battery rating of 20C is normal for this size range and is good.

Make sure you are choosing a motor with the correct RPM/Volts for your props.

Questions:
1. I imagine that will be hard to predict. I would suggest buying one motor, one ESC and one prop, powering it up, and seeing how much thrust it produces at about 12v or so. I doubt there is any way anyone can really give you an answer, just build a simple mock up and see if you will end up with enough force.
2. I take it that the modules connect over the cell phone network like a call or text message, you feed serial data into one module and it comes out the other. If I am correct, you will need two modules.
3. Power supply for the cell module? Battery charger? Cell balancer? You probably thought of that though.

rp181

Thu Mar 18 2010, 03:24AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

That website is one of those Hong-Kong ones that take brand designs and make their own. They are cheap, but their are rarely any disputes with quality, most common complaint is a bad Kv rating thats off by some. Most all of the quadrocopters I have seen use motors from here.

I think I am going to avoid cellular for now due to cost, but may look into it for the future. Something Ive struggled with:
With a application of this type, what kind of range will 60mW 2.4ghz (XBEE) give me?

Bjørn

Thu Mar 18 2010, 04:11AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Search for motor propeller calculator and you will find websites and programs that can calculate the thrust with good accuracy. Join some forums like

where you will find all the information you will never need.

rp181

Thu Mar 18 2010, 09:41PM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

Thanks.
Can you guys look over this too?
--------------------------------------------- QUADROCOPTER-------------------------------------- ----------------------------
4x http:// www.hobbycity.com/hobbycity/store/uh_viewItem.asp? idProduct=4700&Product_Name=hacker_Style_Brushless _Outrunner_20-22L ($14.72)
2x http://www.quadroufo.com/product_info.php? cPath=2_22&products_id=63&osCsid=0ff103e72d7078ca0 6d4af25a19d059a ($8.50)
4x http://www.hobbycity.com/hobbycity/store/ uh_viewItem.asp?idProduct=4312 ($11.90)
1x http://www.hobbycity.com/hobbycity/store/ uh_viewItem.asp?idProduct=2169 ($6.95)
1x http://www.hobbycity.com/hobbycity/store/ uh_viewItem.asp?idProduct=68 ($3.49)
2x http://www.hobbycity.com/hobbycity/store/ uh_viewItem.asp? idProduct=7634&Product_Name=ZIPPY_Flightmax_4000mA h_3S1P_20C_ ($19.99)

TOTAL: $173.9
------------------------------------------- ------------ELECTRONICS--------------------------- ------------------------------

($124.95)-IMU

Is this needed? ($13.95)-programming

($122.95)-main CPU

($71.95)-programming
2x

($37.96)-Xbee

($24.95)-PC receive end

($9.95)-interface MCU

TOTAL: $ 444.61
------------------------------------------- -------------------------------------------------- -------------------------------

EXPENSIVE!

Is their anything Im missing for a complete setup?

Ken M.

Fri Apr 02 2010, 07:34AM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

Nice RP.

I to am working on a Quadcopter albeit mine is going to be RC to begin with but as time progress I'll start adding autonomous operations, now to answer your questions.

Will the motors work YES, I have 20-20L with 9x5 3 blade props and it takes a far bit of strength to keep the motor test assembly in my hand from flying off at full throttle, and from what I have gathered the 10x4.x props are the most popular and produce a good mix of speed and static thrust.

The esc's SHOULD be good enough considering my 20-20L peaks at 13A @ 11.1v full throttle using my 3 blade props, so in theory 18A should work but if you need to go to a bigger motor your limited on how big, kinda why I went WAY over board on my escs and bought the turnigy 40A 50A burst ones Lots of head room with expandability options.

As for if it will fly to help you get some ball park figures

gives some decent thrust calculations, considering your initial concern would be CAN it get off the ground with its fully equipped weight, the calc says 970grams of thrust static at ~7300 RPM so I'd say your looking at a Thrust to weight ratio of about 2:1 it should lift off speed no idea.

As for the compatibility of the IMU and the beagleboard no idea what the board even is (ill look into it) and the link for the IMU doesn't work all the way, I'm using the 6DOF main board

for mine to provide 4axis of stabilization, 1 rotational and an xyz via an accelerometer all being ran threw STmicros Discovery board

as for celluar modules not sure, I was planning on using zigbee or xbee modules due to the "claimed" range they get any where from 1000ft to 40miles.

Maybe as a thought you could try carbon fiber frame (that's what I'm gonna use), also if you want more info on quadcopters to help you if you haven't already hit up rcgroups forum, they have a section dedicated to quadcopters that rivals the size of this forums tesla coil section, and in that quad copter forum they have every bit of info ever accumulated from frame material break limit testing, IMU and stabilization boards, motor and prop combos tests thrust calculations and graphs, heck the most of the topics have about 50+ pages of posts.

Hope this helps, and I'll be paying attention to this thread to see how its coming for ya, and try to help with what limited knowledge I have, and good luck.

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