Accuracy of XPlane HIL Simulation?

Hi all,

I am in the middle of implementing APM into my X8 wing platform. As a final checkout, I would like to do HIL simulation with XPlane. My purpose of using APM is to eventually modify the code, and HIL simulation in this context is important.

My question is this: How accurate is XPlane when used with MissionPlanner? I know XPlane is a realistic full-scale sim. But, this does not necessarily mean that any old full scale aircraft models my flying wing. If XPlane runs the simulation environment, then using an airframe congruent with my physical plane is important. Indeed, if there is a significant difference between the aerodynamics of the XPlane platform and my RC plane, then HIL testing may be misleading my masking issues or creating problems that do not exist. (In technical terms, if my plant model is incorrect, tuning my feedback system is useless.)

Are there numerous RC sized XPlane models? I do not see how using some high-wing full-sized aircraft in XPlane would accurately model a 2-meter flying wing. Am I missing something?

Thanks!

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Replies

  • Thanks all, for the great replies. I think I will definitely go the XPlane route. Does anyone have opinions on XPlane 9 vs 10? I really have no interest in using XPlane outside of APM. XPlane 9 would save me some money and probably run better on my older system.

    @Sid and Eli: Yes. My first thought is to have HIL check for sign errors or stupid mistakes on my part. I'll look at the RC models out there.

    @Jean-Louis: I am a fan of your work. Seeing your posts is what prompted me to think about using XPlane in the first place. I would love to see one of your gliders fly around the Chamonix area...

    @Richard: Wow. Thanks for the wing model. I'll take a look at it once I get XPlane. You saw you can get the XPlane model close to being realistic, but that you will need some PID tuning on the real airframe. Does this mean that you can do some rough PID tuning in XPlane? Thanks for the heads-up on the elevon mixing. I definitely would have tried to use elevon mixing in APM. Is it possible to use CAD STL drawings to make an XPlane model? Would this be overboard: (http://diydrones.com/profiles/blogs/x8-3d-scanning)?

  • Developer

    Have you seen what I done with the HIL simulation with X-Plane v9.70 and the real RC model at:

    http://diydrones.com/profiles/blogs/a-calmato-an-electric-powered-a...

    calmato_hil_mode1.jpg?width=640

    and at:

    http://diydrones.com/profiles/blogs/low-altitude-autonomous-mission...

    MaxiSwiftXplane3.jpg?width=640

    SIncerely,

    Jean-Louis

  • I wouldn't use Xplane for anything other than making sure you know how to operate the system without risking your airframe.

    if you can fly the X8 by hand, you can get it flying with APM. people also share their gains for platforms like that, since so many are in use. 

    ive used xplane to validate things like failsafe behavior and changes to code that I make. mostly to make sure that all my sign errors disappear!

    there are a bunch of rc scale models out there, and its short work to make your own, but they won't really tell you much more about the real world behavior of your model than a high wing trainer model. some features, like trying out clamshell drag rudders can be done in xplane and you can learn about the qualitative behavior of your model, but not much quantitatively. 

    once you get some flying and real data, youll be better able to analyze the accuracy of any xplane model you simulate, anyway

  • You can build your own aircraft models.  X-Plane has an excellent physics engine and if you take the time and build the model correctly you will get a pretty accurate simulation. 

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