For those interested in using their multicopters to carry heavy objects you might be interested in the test that I performed today with Assistant Professor Nagatani-san of Tohoku university in Japan and Izu-san of EnRoute (a company that specialises mostly in Radio Controlled vehicles here in Japan and China).

The goal for later this year is to carry a rover to the top of Mt Asama (a volcano that errupts from time to time) and drop it in mostly as a proof of concept that it can be done.

Today was our first attempt at dropping one of the university's semi-autonomous rovers (2.5kg) from an ArduCopter equipped Zion Pro hexacopter (4.0kg not including the rover).

During the first try the copter was under manual control (stabilize mode) and the servo to drop the rover was activated by the tx/rx's channel 8 switch.  I was the pilot and although we were all fully expecting the copter to climb I was still surprised by the speed of the leap into the air and I couldn't keep the throttle low enough without cutting the engines completely.  You can see the disasterous result 44 seconds in.

After lunch and fixing the hexa the 2nd (1:02) and 3rd tests (1:11) went much better with lower weights (300g and 1kg) and this time using Alt-Hold.

The final test (1:24) was back again with the rover but this time using alt-hold and you can see how much better the new 2.9.1 Alt-Hold is than a human pilot (or at least this human pilot!) with the copter only climbing about 10cm or so.

So the moral of the story is sometimes it's best to trust the autopilot.

Views: 2095

Tags: 2.9.1, Alt-Hold, ArduCopter, EnRoute, Rover, Tohoku, University

Comment by Dany Thivierge on February 11, 2013 at 9:08am

wow, thanks for including the manual mode crash, it really show how the auto pilot react to that big weight / thrust change.  again good job on the code guys! 

Comment by Rob_Lefebvre on February 11, 2013 at 9:32am

Nice test Randy!  This is something I have been interested in doing.  That is surprising how quickly it shot up.  Wouldn't be a problem if not for the ceiling! And it is a great demonstration of how good Alt_Hold is!

Do you have any plan to retrieve the rover after?

If you hadn't heard of it yet, check out the OpenGrab project.  It's a magnetic system, would make for a simple release, and may allow you to retrieve too.

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Comment by Chris Anderson on February 11, 2013 at 10:11am

Love it. Third time's the charm!

3D Robotics
Comment by Alan Sanchez on February 11, 2013 at 11:31am

Awesome Randy! Sam and I have been meaning to do something similar for a while now but can never get to it. Keep it up!

Comment by Peter Meister on February 11, 2013 at 12:59pm

Awesome Randy, thanks for sharing this. It's neat to see the difference in manual vs. stabilize with the drop!

Comment by Jiro Hattori on February 11, 2013 at 3:14pm

You did it! 

Congratulations for great Alt_Hold software, as usual.

Want to see actual testing very soon.

BTW, your testing took place indoor.

Is it relies upon ultra sound sonar to detecting altitude (distance really)? 

Comment by Jack Crossfire on February 11, 2013 at 5:53pm

It needs to be lowered on cables & you need a mohawk.

Comment by Randy on February 11, 2013 at 5:53pm


     No hard plans yet to try and get the rover back although it's been discussed.  I'll point those guys at the open grab project.


     no sonar on that rig.  Just using the regular 2.9.1 alt-hold which is inertial nav + baro.

Comment by Randy on February 11, 2013 at 5:59pm


      Yes, a cable would be ideal.  then the release could be done manually (or it would become even easier for the autopilot).  Sadly my hair options have become extremely limited. :-).

Comment by Richard Boyhan on February 12, 2013 at 8:53am
Very cool. It's said that most crashes are caused by pilot error. I can honestly say that all mine have been my fault. Thanks for sharing.


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