Drones and ROVs and Arduinos

A journey building drones and ROVs and other open hardware and Arduino based stuff

Arducopter ready to fly (with bonus indoor flight crashing)

Over the last 2 weeks I completed the assembly of the Arducopter, which is now just waiting to be taken out and tested with a bit of space around.

Arducopter ready for first flight

This was a pic of the final result, but let’s go through the other steps of the building process.

Arducopter Frame

After the soldering of the power distribution board and assembling the motor’s arms, the next step has been assembling the frame.

The process was pretty easy, but a bit longer than I expected expecially because of all those little screws that kept falling off. Also I had a bit of problems trying to fix both the APM and the received to the frame. At the end I just fixed the receiver with a zip tie, but not the APM.

Bare frame assembled

Here the timelapse of the frame assembling part:

Routing cables and mounting APM

One week later, I went with the assembling: I routed all input and output wires, and mounted the APM on the frame.

I decided to fix the APM to the middle plate, by taping with a double-sided foam tape the APM2 case (and making sure it doesn’t fall off by using some zip-ties). I had a bit of problem fitting the APM in its case because the pins used to keep the daughterboard were too high and were interfering with the top of the case, so I had to cut them off.

I attached the receiver on one side of the top plate, so that it doesn’t cover the GPS.

Here the time-lapse of that part, too.

Assembling and balancing props

Before going to the firmware upload process, I wanted to get all the hardware parts ready, and the last bit missing was propellers balancing and assembling.  I found out that in one of the bags I had 2 CW propellers instead of one per type: I’m glad I had ordered 4 bags of props instead of just 2. I tested for balance in props using a paper clip and some normal tape.

As usual, the raw unedited timelapse of that part:

Uploading the firmware and bench tests

And then it came the time to upload the firmware, to do the calibration of radio signals, ESCs, to verify the right direction of motors and checking the chart of sensors were moving in the right direction.

The bench power supply I did turned out to be very useful for testing and calibration.

Nothing strange to report during this phase: also the ESC calibration, which usually is pretty complicate and is causing us a lot of pains in OpenROV, was completed successfully at the first attempt.

Attaching propellers and marking the front of the drone

The last steps included mounting the props and sticking a hi-reflective orange sticker to make the front arm.

Bonus video: First test flight

After everything was assembled, I tried taking off indoor (was already pretty late and dark, and didn’t have battery for the radio transmitter).

At the beginning you can see the copter tilting always on the same side, the back arm: that was caused by the motor turning in the wrong direction: I switched the motor wires and immediately the quad started to hover just a bit.

The yaw was working perfectly, but when I tried raising the throttle and actually taking off, the quad was drifting a bit on the side. This could be caused by a few reasons:

  • One motor or arm is a bit tilted, so is “pulling” slightly diagonally and not precisely on the vertical
  • The APM is not flat and tilt not correctly statically compensated
  • The copter is getting trapped in its own turbulence given the (small) size of the room

Some in-flight auto trim is needed, but first I’ll have to check for tilted or bent arms, and try to re-calibrate the accellerometer on a flat surface.

Here is a video of my first flight:

Videos

What you have seen here were just some raw unedited cuts of the assembly time-lapse. When the copter flies I’ll make a nicer (and shorter) video with all the steps.

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This entry was posted on December 17, 2012 by in Arducopter and tagged , , , , .
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