Pixhawk/Ardupilot VTOL---> Forward Flight


I was told some time ago that if you want to just fly a VTOL aircraft ardupilot is great but if you want to add capabilities (extra sensors and servo's), you should couple it with a pixhawk. I have been browsing forums to find out if this is true and haven't found supporting information. Is this true?

More specifically for a class, we are building a demonstration model of a fire suppression aircraft that needs to transition between VTOL and forward flight, as well as operate at least one servo to control water deployment, possibly a gimble and a couple camera's as well.

I am looking into the controllers to use for this. We likely will be creating a non-conventional model and possible have swarm capabilities to attach more than one aircraft together. Has anyone conquered any of these tasks that would be willing to give me a 101 on controller setups? 

Someone here at school recommended a KK2 but I really think we would not be able to control all of our moving parts. Another person recommended a DJI lite but i am fairly certain DJI is so streamline that it would be difficult to use unique hardware setups.

Thanks for any advice/learning resources can give.

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  • Jordan,

    This thread may give you some ideas if you decide to use a Pixhawk with the APM stack.

    APM: QuadPlane, Tiltrotor, and Tiltwing

  • 3D Robotics

    The VTOL vertical-to-horizontal flight part is easy and is natively supported on Pixhawk today with both the PX4 and APM firmware. In the case of PX4 that's just a button that you click in the QGroundControl ground station to select VTOL. Works right out of the box. 

    But the other things you want to do, such as carrying water, are hard. 

  • What you plan to do is monumental.

    Swarm - No, not possible now with pixhawk due to GCS software limitations.  Universities and military can do it, but with a $400,000 computer and a dedicated lab.

    Multiple bodies for an aircraft - way beyond what even experienced builders with funding can do.  There might be one or two examples of that ability IN THE WORLD.  To give you an example, there are about 1400 known working UAV's on the market in the world today with about 300 being developed, none of them can do this particular ability, YET.

    KK Flight controller - don't waste your time, it is meant to only keep a drone in the air and that drone can only accept inputs from the pilot.

    I've been where you are and I've seen University projects too.  Here is my advice:  Get the Pixhawk 2 with the standard circuit board expansion.  Start on page one of either the multi rotor OR plane wiki for the Pixhawk 1 as they are the same when it comes to the firmware that you will load on it.  Read ALL OF IT, every bit!  No text book will teach you how to use an autopilot system as good as those wikis will, and no text book will ever cover a specific autopilot as it is not the job of your teacher or a text book to do so.  Autopilots are very specific and very general at the same time. 

    Read one wiki but not the other (plane or multi) because if you read both you stand a good chance of either getting bogged down or confused.  Later on, after you have one working drone under your belt then decide if you want to venture on with a different aircraft or another of the same kind.

    It's a long LONG road to get proficient with these machines but the payoff is as close to having a super power as you can get.

    As for VTOL with fire suppression.  I think that's a great project for college but in the real world we would not pursue the combination of VTOL with heavy payload.  It is a matter of power available to keep the aircraft in the air, it won't fly long at all as the capacity of batteries as they are now are useful but only with light payloads.  VTOL also has a price of being power hungry compared to a non VTOL aircraft due to the extra weight of having more motors and less efficient aerodynamics due to the same motors having to be carried without contributing all the time to flight itself.

    VTOL alone is a great goal for a college project, but I'm afraid fire suppression being added will result in bad things happening.  Make a blog for us on it because I'd love to follow your project!

    Good luck bud, and if it ain't fun you are doing it right!

  • I might add time constraint is more of a barrier than money. We have University funding so if Pixhawk works better, can control several inputs, and can be learned quickly with APM experience I will probably go with it. We have the academic year to complete it, however I know it takes some time to get used to and troubleshoot controllers. I would prefer to order our controller right away.

  • I am most familiar with APM, do you think it would be good to stick with APM? Is there a way to couple APM and Pixhawk? (It looks like APM has more input ports than Pixhawk).

    Was my friend right in saying processing power is greater in Pixhawk? Is it even a noteworthy difference?

    Based on our hardware configuration we may have to modify some libraries that control stability. Do you know of any good resources for generating these configurations? I have a Flight Dynamics Book and fear I may just have to muscle through the book and make it from the ground up, but if there is a shortcut I would love to know about it.

  • Moderator

    The PX4 and Pixhawk is a generational increment from the APM,

    -the KK2 is a flight controller,

    -DJI is closed source plug'n play system with limited access for DIY tinkering.

    The APM is still a good DIY solution.

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