Ardupilot and beyond

So, it's time to start my personal UAV project, and contribute back to this community. First, I've bought an Ardupilot system as specified on the homepage. I'm using the EM406 for now, although I expect to upgrade when budget permits. To keep things simple at first, I'm using a stock EasyStar.Once I have the basic system working, my next step is to add code and/or hardware to enable waypoint changes in flight, or lower-level path control from a separate (ground or onboard) computer, and a camera subsystem. A move to a larger aircraft and test series to tune the autopilot to that aircraft will also be needed.The ultimate goal is to improve the system to meet the specification for the AUVSI Student UAS competition. I've competed in that competition using Micropilot and Piccolo autopilots, as part of the Embry-Riddle SOAR team, so I have a good idea of what's needed.Next post, I'll talk about details of my system build, and the decisions I've made within the Ardupilot manual instructions.

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Mike Bakula November 2, 2009 at 11:57am

My platform is a modified Multiplex EasyStar.

The wing is stock, but I've increased the size of the rudder for 4 sq. in. to 8 sq. in. The new rudder is MonoKote over balsa. I started with a piece of 1/4 in. sheet, then sanded a taper in to 1/8 in. at the trailing edge. The hinges and control horn are DuBro hardware.

On the right side, you can see the sensors and XBee module. I decided to place the X-Y sensor on the same plane as the wing, to minimize blockage. For now, the pitot is attached with velcro, but I'll mount it more securely once I have an orientation I'm happy with. The motor is an E-flite 6-series 2700 Kv motor. It fits the space provided for the included brushed motor, but I had to route the wires carefully to avoid blocking the air inlet. The propeller is an APC 6x3 glow engine prop. (I had to ream the hub to allow it to fit the prop adapter.)

The left side shows the u-blox GPS (I upgraded from the EM-406), and the Thunderbird-54 motor controller, along with the wiring to the brushless motor. I mounted the controller outside the fuselage for proper cooling.

I modified the canopy to use magnets to secure it. Inside, the Ardupilot, AR6200 receiver, and a ThunderPower ProLite V2 (2100 mAh, 3s, 20C) LiPo battery provides power for the entire system. The entire vehicle weight is 26 oz, and the CG is 69mm from the leading edge, about 9 mm ahead of the nominal CG from the book.

First flight was last week, under R/C control -- trims look good, and the plane is capable of ROG off of grass, and vertical launches. Now to load up firmware 2.4 and find time to get to the test area...
Mike Bakula October 8, 2009 at 5:37pm

Thanks for the tip!

Here you can see the left side -- the Spektrum AR6200 receiver is forward, and the and the Xbee on its Adafruit adapter is aft. (I had to invert the regulator and filter cap to get the XbeePro to fit.)

The right side shows the motor controller and battery, as well as the Z-sensor. Everything is low-temp hot glued for now, so it'll be easy to remove the parts later when I install them in the plane.

The top shows the X-Y sensor, the GPS, the Ardupilot and shield (no pitot tube for now), and the undersides of the two servos. I set the servos to match their orientation on the Easystar.
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Chris Anderson October 8, 2009 at 3:34pm

Looks good, Mike. Just a FYI: if you click the little camera icon the pictures will be embedded, not attached, which make it a lot easier for readers.
Mike Bakula October 8, 2009 at 3:24pm

Instead of boring text, I'll start with some photos of my build so far. I have my system assembled on a ground-test rig. so I can get comfortable with how things work, and show the hardware to the folks at school. (The team is considering an Ardupilot derivative for the AUVSI Student UAS competition.) The structure is just black foamcore, and the control links are out of my junkbox.

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Ardupilot and beyond

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