Glider with PX4 and Pixhawk 4

Hi all,

I am working on a new project with fellow students/engineers with a hope to implement PX4 on a unpowered vehicle.

The vehicle is in a design phase. The idea is to have it dropped at certain altitude and then track back to the original location of launch. We know that it may not necessarily reach that location since it is just gliding, the goal is to track back to that location and when at certain altitude deploy a parachute.

So my questions are as following…

  1. Would such thing be possible with Px4? The way we see it is that it’s just using ailerons and elevators to maintain certain attitude thus maintaining certain glide speed, and tracking to the home position. However since we had no previous contact with Pixhawk and Px4 we don’t know how realistic this is?

  2. Would it be possible to further develop Px4 software to navigate by internal sensors instead of gps? So to have something like inertial navigation system. Px4 using accelerometers and gyros to create to calculate it’s position independently of GPS?

Thanks
Dusan

Hi DusanP,

  1. Yes, it’s possible. The PX4 has all required sensors. Some of them even doubled.
    IHMO, to make a glider you need just accelerometer and compas (OK, baro is nice to have). Even gyro is not required because the glider will fly by them-self.
  2. No. It’s not possible with accepted errors. If you don’t know speed of the wind, you will not be able to identify the position, and accelerometer error is to big for double integration.
    But…
    If you will know the gliding quality, it’s possible to calculate wind speed and current position. But for that you need to make very big EKF with very good model of your glider. I think in this case it will be possible to calculate current position with ~5-30 % error for distance. Additionally you will need additional air speed sensor (OK, my be two or three air speed sensors).

Regards,
Dmitry