Issues with Arming and RC Input - Fixed Wing

PX4 Autopilot
1

Hi,

I am using a Pixhawk 6C, PX4, and QGC to build an unmanned surface vessel (USV). I am also using a Taranis QX7 transmitter and X8R receiver both on ACCST protocol. I am super close to putting the USV in the water but have to work out one last bug with the manual control after arming it. I am using the fixed wing airframe and controlling the stability and movement using a custom built XY stage that modulates the center of mass to control roll and pitch. In essence, and for simplicity, these rails are defined in QGC as an elevator and rudder, as that is essentially what they are doing, with the forward and backwards motion on one rail controlling the pitch like an elevator, and the side to side motion on the other controlling the roll like a rudder. I got this set up so that in the actuators tab I can move everything perfectly with the sliders, and it’s tuned so that the full length of each rail is used. I have also connected, minded, and calibrated the RC input through QGC and mapped the channels to the sticks and switches I want them to be on.

However, when I arm the USV to “fly” the rails no longer work the way I want them to on RC control. In stabilized mode, I am able to tilt the Pixhawk and the “elevator” corresponds to this movement to counteract and stabilize pitch. This does not work when I tilt the pixhawk in roll at all. And RC input in either direction is not working in stabilized mode. I also tried this in manual mode to get direct RC input and again got no movement when using the transmitter.

I am new to using a Pixhawk so I am not really sure if this is a common issue or I am making a simple mistake somewhere. I don’t really know where to start, where to go, and what to do to debug this so any help would be greatly appreciated. Also happy to add clarifying details if needed.

Thanks,
Adam

2

Hi, could you upload a log to http://logs.px4.io and share the link here? If possible, clearly do a sequence of pitch motion, roll motion, RC pitch input, RC roll input, so we can see which part is not working properly.

3

Thanks for your response. Here’s the link to the test that I did. Hopefully it shows what you’re looking for but if not I can repeat. I first manually tilted the Pixhawk in pitch then roll. The physical response to pitch tilting was good, but no response to roll tilting. Then I moved the sticks on the RC for pitch then roll. There was a slight response to pitch manual control but no response to roll manual control. Any help or further insight is greatly appreciated.

Thanks,

Adam