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May 08 2012

Arducopter Back in Flight

After a steep learning curve for Arducopter, we have it flying.  Garret left us the Arducopter after graduating, I had never so much as worked with Arducopter before.  Of course I had never worked with Mikrokopters either, but Jonathan was here to teach me everything I need to know about them.  I didn't have that luxury for Arducopter, so progress was a bit slower.

The first thing I did when Istarted working with the ardu was to load new firmware and update to the new mission planner.  Since this was all new software, the Arducopter had to be calibrated from scratch.  After crashes during motor tuning, we had multiple delays while waiting for new parts to come in.

But the Arducopter is flying now, and not a moment too soon.  With summer rapidly approaching and all the orders in, I'm going to start building the Octocopter very soon.  It gives me some assurance that I was able to get the quad Arducopter flying, since the Octocopter also uses Ardupilot.

Apr 26 2012

Arducopter Progresses, Octocopter Components Still Arriving

It’s been slow going with the Arducopter, working with it this semester has often seemed like two steps forward and one step back.  However after several stumbling blocks like the Ardupilot board being of the older model now, and  ailing Electronic Speed Controllers:  things are starting to look up!

I was able to update the Arducopter to four brand new ESCs, since one of our big orders just came in (will get to that in a bit).   Earlier we’d had trouble calibrating the Arducopter for flight, it kept wobbling and flipping over.  I feel rather foolish now; the problem was that the ESCs were mismatched!  One had been replaced because it was suspected to be burned out.  I only yesterday realized that of course it would need four identical speed controllers to fly stabile.  Since our Octokopter order of ESCs came in, there were enough spares to outfit the Arducopter for testing.

So a new order did come in!  Our large order from DIYDrones is now in the lab: it included ESCs, propellers, power distribution boards, and Ardupilot boards.  Combined with our previous order from Aeroquad (Mikrokopter OctoXL Frame), we now have most of the components to build an Octokopter, and enough spare parts to build a second one (minus what we’re still waiting on.)  The jDrones order went out yesterday; it was mostly parts that have been out of stock until now.  This order includes the last set of components we’ll need to make a working Octo, the motors.

Things are looking good for the next gen of Ecosynth aircraft; at this point I think that Octokopter work will start as soon as summer research starts, when aircraft moves into the bigger lab.

Mar 16 2012

Updates: Hexakopters, Quad Arducopter and Octocopter.

Now that the hexakopters are basically complete (one has a programming error that we are currently working on), Stephen and I decided to work with our other projects: quad arducopter and octocopter.

The quad arducopter (4 blades) is working.  We spent a few days familiarizing ourselves with the parts of the copter using the arducopter wiki (http://code.google.com/p/arducopter/wiki/ArduCopter).  The electronic speed controller (ECS) still needs to be calibrated, but it the copter is connecting to the computer and seems to be in working order.  We have started the parts list so that we can move forward.

The octocopter (8 blades) is still in the supply obtaining phase.  We have already placed our order for the necessary parts to construct the copter.  Within a few weeks we shall have those supplies and can commence the construction!  The objective of the octocopter is to run the trials the hexakopters are currently doing, but more efficiently.  It is also hoped that we can use the octocopters to expand the scanning area. 

Jul 27 2011

ArduPilot/ArduCopter Update

As many of you know our attempt at photographing Elbow Ridge Farm via two EasyStars this past weekend was anything but successful. Although the primary issue of Auto mode being inactive was eventually resolved at the field by trimming the endpoints on the mode toggle switch, we were still unable to fly our missions due to the system failing to obtain a GPS lock. Even after that weekend when the GPS was relocated to a more familiar region it was unable to obtain a GPS signal. Out of frustration I had decided to clear the GPS settings and delete the current firmware. Starting from scratch I reloaded both the firmware for the GPS as well as a script which enables it to communicate with the ArduPilot. In doing this I had also updated the GPS to a more recent firmware version. Just as it had in the past the ArduPilot was able to get a GPS lock within 5 minutes of being powered up (as indicated by the solid blue LED on IMU shown in the above picture). I’m planning on flying a short mission with the EasyStar tomorrow afternoon to make sure everything is working as it should be. Hopefully this will better prepare us for our next trip to Elbow Ridge Farm.

This week Jonathan had given me the camera mount and landing gear from one of the old Gaui quads so I could attach it to the new ArduCopter system. I just figured I’d post a picture of the new setup. The landing gear had to be extended by 2 in to provide enough clearance for the camera so I drew up a CAD model and laser cut a set of extensions out of 1/8’’ thick plastic sheet (triangular support structure on bottom). I had also added a servo to the camera mount and attached it to one of the output ports on the ArduPilot Mega to provide automatic camera stabilization. So far it seems to work great but we’ll need to upgrade the stabilizing servo if we plan to fly missions with camera stabilization activated.       

Jul 09 2011

ArduCopter Build and Flight Testing

Over the past week I’ve been spending some time building and setting up our new ArduCopter Quad. Although our ultimate goal is to develop a fully autonomous hexacopter we decided to use the quadcopter  frame to familiarize ourselves with the ArduCopter code and hardware. To simplify the building process a mikrokopter hexakopter frame was used and assembled in a quad formation. Plates were custom made from HDPE sheets to mount the electronics on. The power system consists of 4 880 kV motors, 30 Amp jDrones ESCs and 12 x 4.5 props. XBees are being used to provide wireless telemetry.

After building the copter and setting up/loading the code I was able to start adjusting the PID gain values. To help with this process, which often involves a good amount of crashing I had decided to build a testing rig out of two eye hooks, 20lb test fishing line, a lead fishing sinker and a metal coat hanger. The hanger was mounted to the quad’s frame so that the fishing line could be tied to it and support the quad near its CG. The fishing line was threaded through the two eye hooks which were mounted to the ceiling. The sinker was tied to the end of the string after the second eye hook such that at its lowest point it was 2 feet off the ground. As the quad took off the sinker pulled the line taught to get rid of any extra slack in the line. If anything were to happen to the quad in flight I could simply cut the power and let the line catch it.  This setup allowed the quad to fly freely without running the risk of hitting the ground or getting the fishing line caught in a prop.

Once the copter had begun to stabilize itself I decided to cut the support line and do some test flights, all of which went without any problems. Because it was dark outside and the grass was wet I had decided to just fly in stabilization mode under my carport. I was able to get the quad to the point where all you had to do was throttle up and it would fly itself (picture of it flying on the left, no strings attached I swear : ). I was so confident in the quads performance that I let my dad try it out and he was able to fly it (he had never flown an airplane or helicopter on his own before). Tomorrow I’ll take it out back to start playing with the loiter and altitude lock modes. I was able to get GPS lock tonight but haven’t started up the XBees. As we’ve found in the past XBees know no limits when it comes to being stubborn.

I’ve also been looking into waypoint navigation with the ArduCopter system and it seems that ArduPirates has successfully developed a roundabout way for flying waypoints. This involves editing the ArduCopter’s GPS lock code with predefined waypoints and inserting loop counters for each waypoint to indicate the amount of time spent at a given location. So essentially your still in GPS lock but switching up the home location throughout the flight.  

I have a video as well but I can’t seem to get it to copy to my computer. Once I figure it out I’ll upload that was well. I’ll update the blog as I continue to make progress.