Recently, I was asked to shoot some stills and footage of a sportfishing yacht for a client. We went out on a beautiful morning with no wind and an almost perfectly calm ocean. If you wanted optimal conditions, its wasn't going to get much better than that morning.
I connected the battery to my custom built quadcopter running APM 2.6. It would not arm. We were sitting about 4 miles off shore, not moving, gently rocking on an ocean about as calm as I've seen it. I was trying to launch from the middle of the lowest platform of the boat, at the stern. I had good GPS. Everything else checked out. It would not arm.
As soon as I got back to dry land, I tried it again. It armed without hesitation. Apparently Arducopter needs to be on solid ground to initialize. So what next?
Arducopter 3.3
In doing my research, I found this thread:
http://diydrones.com/forum/topics/launch-and-recovery-from-boat
Chris Anderson says, "Starting with 3.3, calibration on a moving surface will be easier. As far as the gimbal goes, it depends on the make. The 3DR Solo gimbal will calibrate on a boat, but not all will"
I have two points here. First, the gimbal is not an issue for me. Simple BGC lets you turn off the startup accelerometer calibration. It still works fine if you don't let it calibrate every time. Second, I'm using APM 2.6 so I'll have to upgrade to Pixhawk if I want to use Arducopter 3.3.
Arm on Shore first
Next, I found this thread:
http://diydrones.com/forum/topics/launching-from-a-moving-boat-can-it-be-done
The first person to comment boots his quad on shore, then takes it powered up, in his kayak. I see where that could work but that only gives me the use of one battery.
Bring a Laptop?
Considering the idea of calibrating on shore, what if I brought my laptop on the boat with me? I could power up on shore then launch from the boat and fly the first battery. After I return to the boat, I could connect APM to the laptop with USB, then disconnect and swap the flight battery for a fresh one. Would this work? I will do some experiments and post the results on this thread.
Dynamic RTL is a Separate Issue
I've already posted the desire for Dynamic RTL, where the copter returns to YOU instead of the original launch location. Obviously this is desirable for any mission launched from a boat. It seems like a much easier feature to add. The Tower app already knows your GPS location in order to do "follow me" mode. The DJI Inspire already has this feature. My thread is here:
http://diydrones.com/group/arducopterusergroup/forum/topics/dynamic-rtl-can-apm-or-pixhawk-do-it-can-tower-do-it-dji-inspire
I will post more information as I find it. Hopefully this thread will be a resource for those wanting this feature.
Replies
getting the gimbal to have enough power and adequate motors to handle the load would seem to be the challenge.
Boy that's a lot of work I'm almost positive that 'boat mode' will be out in 3.4 you might want to just wait?? Good luck.
Thanks Richard for your comment. I agree.
The motors I priced to do this job were enough to put me off the idea.
I have plenty of other things to build anyway. :-)
I had actually thought about doing the same thing. I was going to use foamcore or styrofoam insulation for the platform. A gyro stabilized platform could work as well and I was thinking about building one using a wheel that you could spin up with a handheld motor. Cameramen that shoot from from helicopters frequently attach their cameras to portable gyros but they are expensive.
But, I don't think any of these complicated solutions are necessary. I found a very simple temporary solution that should work until they come out with 3.4. I made a little video about it and I'll be posting it in a few minutes...
We have spent a lot of time evaluating this problem as engineers. We have a test rig that allows us to measure how stable for how long before arming. It seems to us the worst controller is Pixhawk-APM, the Pixhawk-PX4 is much less sensitive. Many others are even less sensitive. IMHO all that is necessary is to relax the limit set for the gyro/compass moment before allowing arming.
Randy has been involved in this discussion for some time and think perhaps a change is in the works.
Hey there! What did you think of the video I just posted? Could there be an easy way to arm the controller on land and then have it remember those settings while you go out in your boat and fly several batteries?
Wouldn't that be far easier than changing limits?
Do you know if it would be safe to connect a portable USB battery to the controller?
Thanks!!
This small lipo to usb charger seems to work fine so would be a handy thing to use with your idea. It connects to the balance port on the lipo and then provide 5v via usb
Thanks Richard, that looks pretty cool!!
For anyone else reading this, here's the link.
The specs say:
USB Output: 5V/1000mAh
Input Voltage: DC 7.5~25.2V
Cell Checking: 1~6S Lipoly
Input Cut-Off Voltage: 3V per cell
My Macbook Pro USB output is 900mA
You should get in touch with the SnotBot people: https://www.kickstarter.com/projects/snotbot/snotbot-pushing-the-fr...
Thanks Randy!
We don't really make it easy to arm from a boat in Copter-3.2.1 or even Copter-3.3 because of the gyro calibration step that's required. Surely for Copter-3.4 it'll be easy.
It's amazing how many people ask for this. I guess it's important!
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